# Vulkan® 1.2.135 - A Specification (with all published extensions)

The Khronos® Vulkan Working Group
version 1.2.135, 2020-03-21 11:52:58Z
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Copyright 2014-2020 The Khronos Group Inc.

This Specification is protected by copyright laws and contains material proprietary to Khronos. Except as described by these terms, it or any components may not be reproduced, republished, distributed, transmitted, displayed, broadcast or otherwise exploited in any manner without the express prior written permission of Khronos. Khronos grants a conditional copyright license to use and reproduce the unmodified Specification for any purpose, without fee or royalty, EXCEPT no licenses to any patent, trademark or other intellectual property rights are granted under these terms.

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This Specification has been created under the Khronos Intellectual Property Rights Policy, which is Attachment A of the Khronos Group Membership Agreement available at https://www.khronos.org/files/member_agreement.pdf, and which defines the terms 'Scope', 'Compliant Portion', and 'Necessary Patent Claims'. Parties desiring to implement the Specification and make use of Khronos trademarks in relation to that implementation, and receive reciprocal patent license protection under the Khronos Intellectual Property Rights Policy must become Adopters and confirm the implementation as conformant under the process defined by Khronos for this Specification; see https://www.khronos.org/adopters.

This Specification contains substantially unmodified functionality from, and is a successor to, Khronos specifications including OpenGL, OpenGL ES and OpenCL.

Some parts of this Specification are purely informative and so are EXCLUDED from the Scope of this Specification. The Document Conventions section of the Introduction defines how these parts of the Specification are identified.

Where this Specification uses technical terminology, defined in the Glossary or otherwise, that refer to enabling technologies that are not expressly set forth in this Specification, those enabling technologies are EXCLUDED from the Scope of this Specification. For clarity, enabling technologies not disclosed with particularity in this Specification (e.g. semiconductor manufacturing technology, hardware architecture, processor architecture or microarchitecture, memory architecture, compiler technology, object oriented technology, basic operating system technology, compression technology, algorithms, and so on) are NOT to be considered expressly set forth; only those application program interfaces and data structures disclosed with particularity are included in the Scope of this Specification.

For purposes of the Khronos Intellectual Property Rights Policy as it relates to the definition of Necessary Patent Claims, all recommended or optional features, behaviors and functionality set forth in this Specification, if implemented, are considered to be included as Compliant Portions.

Where this Specification includes normative references to external documents, only the specifically identified sections of those external documents are INCLUDED in the Scope of this Specification. If not created by Khronos, those external documents may contain contributions from non-members of Khronos not covered by the Khronos Intellectual Property Rights Policy.

This document contains extensions which are not ratified by Khronos, and as such is not a ratified Specification, though it contains text from (and is a superset of) the ratified Vulkan Specification. The ratified versions of the Vulkan Specification can be found at https://www.khronos.org/registry/vulkan/specs/1.2/html/vkspec.html (core only) and https://www.khronos.org/registry/vulkan/specs/1.2-khr-extensions/html/vkspec.html (core with KHR extensions).

Vulkan and Khronos are registered trademarks of The Khronos Group Inc. ASTC is a trademark of ARM Holdings PLC; OpenCL is a trademark of Apple Inc.; and OpenGL and OpenGL ES are registered trademarks of Hewlett Packard Enterprise, all used under license by Khronos. All other product names, trademarks, and/or company names are used solely for identification and belong to their respective owners.

## 1. Introduction

This document, referred to as the “Vulkan Specification” or just the “Specification” hereafter, describes the Vulkan Application Programming Interface (API). Vulkan is a C99 API designed for explicit control of low-level graphics and compute functionality.

The canonical version of the Specification is available in the official Vulkan Registry (https://www.khronos.org/registry/vulkan/). The source files used to generate the Vulkan specification are stored in the Vulkan Documentation Repository (https://github.com/KhronosGroup/Vulkan-Docs). The source repository additionally has a public issue tracker and allows the submission of pull requests that improve the specification.

### 1.1. Document Conventions

The Vulkan specification is intended for use by both implementors of the API and application developers seeking to make use of the API, forming a contract between these parties. Specification text may address either party; typically the intended audience can be inferred from context, though some sections are defined to address only one of these parties. (For example, Valid Usage sections only address application developers). Any requirements, prohibitions, recommendations or options defined by normative terminology are imposed only on the audience of that text.

| Note Structure and enumerated types defined in extensions that were promoted to core in Vulkan 1.1 are now defined in terms of the equivalent Vulkan 1.1 interfaces. This affects the Vulkan Specification, the Vulkan header files, and the corresponding XML Registry.

#### 1.1.1. Normative Terminology

Within this specification, the key words must, required, should, recommended, may, and optional are to be interpreted as described in RFC 2119 - Key words for use in RFCs to Indicate Requirement Levels (https://www.ietf.org/rfc/rfc2119.txt). These key words are highlighted in the specification for clarity. In text addressing application developers, their use expresses requirements that apply to application behavior. In text addressing implementors, their use expresses requirements that apply to implementations.

In text addressing application developers, the additional key words can and cannot are to be interpreted as describing the capabilities of an application, as follows:

can

  This word means that the application is able to perform the action described.

cannot

  This word means that the API and/or the execution environment provide no mechanism through which the application can express or accomplish the action described.

These key words are never used in text addressing implementors.

| Note There is an important distinction between cannot and must not, as used in this Specification. Cannot means something the application literally is unable to express or accomplish through the API, while must not means something that the application is capable of expressing through the API, but that the consequences of doing so are undefined and potentially unrecoverable for the implementation (see Errors).

Unless otherwise noted in the section heading, all sections and appendices in this document are normative.

#### 1.1.2. Technical Terminology

The Vulkan Specification makes use of common engineering and graphics terms such as Pipeline, Shader, and Host to identify and describe Vulkan API constructs and their attributes, states, and behaviors. The Glossary defines the basic meanings of these terms in the context of the Specification. The Specification text provides fuller definitions of the terms and may elaborate, extend, or clarify the Glossary definitions. When a term defined in the Glossary is used in normative language within the Specification, the definitions within the Specification govern and supersede any meanings the terms may have in other technical contexts (i.e. outside the Specification).

#### 1.1.3. Normative References

References to external documents are considered normative references if the Specification uses any of the normative terms defined in Normative Terminology to refer to them or their requirements, either as a whole or in part.

The following documents are referenced by normative sections of the specification:

IEEE. August, 2008. IEEE Standard for Floating-Point Arithmetic. IEEE Std 754-2008. https://dx.doi.org/10.1109/IEEESTD.2008.4610935 .

Andrew Garrard. Khronos Data Format Specification, version 1.3. https://www.khronos.org/registry/DataFormat/specs/1.3/dataformat.1.3.html .

John Kessenich. SPIR-V Extended Instructions for GLSL, Version 1.00 (February 10, 2016). https://www.khronos.org/registry/spir-v/ .

John Kessenich, Boaz Ouriel, and Raun Krisch. SPIR-V Specification, Version 1.4, Revision 1, Unified (December 14, 2018). https://www.khronos.org/registry/spir-v/ .

Jon Leech and Tobias Hector. Vulkan Documentation and Extensions: Procedures and Conventions (July 20, 2019). https://www.khronos.org/registry/vulkan/specs/1.1/styleguide.html .

Vulkan Loader Specification and Architecture Overview (August, 2016). https://github.com/KhronosGroup/Vulkan-Loader/blob/master/loader/LoaderAndLayerInterface.md .

## 2. Fundamentals

This chapter introduces fundamental concepts including the Vulkan architecture and execution model, API syntax, queues, pipeline configurations, numeric representation, state and state queries, and the different types of objects and shaders. It provides a framework for interpreting more specific descriptions of commands and behavior in the remainder of the Specification.

### 2.1. Host and Device Environment

The Vulkan Specification assumes and requires: the following properties of the host environment with respect to Vulkan implementations:

- The host must have runtime support for 8, 16, 32 and 64-bit signed and unsigned twos-complement integers, all addressable at the granularity of their size in bytes.

- The host must have runtime support for 32- and 64-bit floating-point types satisfying the range and precision constraints in the Floating Point Computation section.

- The representation and endianness of these types on the host must match the representation and endianness of the same types on every physical device supported.

| Note Since a variety of data types and structures in Vulkan may be accessible by both host and physical device operations, the implementation should be able to access such data efficiently in both paths in order to facilitate writing portable and performant applications.

### 2.2. Execution Model

This section outlines the execution model of a Vulkan system.

Vulkan exposes one or more devices, each of which exposes one or more queues which may process work asynchronously to one another. The set of queues supported by a device is partitioned into families. Each family supports one or more types of functionality and may contain multiple queues with similar characteristics. Queues within a single family are considered compatible with one another, and work produced for a family of queues can be executed on any queue within that family. This Specification defines four types of functionality that queues may support: graphics, compute, transfer, and sparse memory management.

| Note A single device may report multiple similar queue families rather than, or as well as, reporting multiple members of one or more of those families. This indicates that while members of those families have similar capabilities, they are not directly compatible with one another.

Device memory is explicitly managed by the application. Each device may advertise one or more heaps, representing different areas of memory. Memory heaps are either device local or host local, but are always visible to the device. Further detail about memory heaps is exposed via memory types available on that heap. Examples of memory areas that may be available on an implementation include:

- device local is memory that is physically connected to the device.

- device local, host visible is device local memory that is visible to the host.

- host local, host visible is memory that is local to the host and visible to the device and host.

On other architectures, there may only be a single heap that can be used for any purpose.

A Vulkan application controls a set of devices through the submission of command buffers which have recorded device commands issued via Vulkan library calls. The content of command buffers is specific to the underlying implementation and is opaque to the application. Once constructed, a command buffer can be submitted once or many times to a queue for execution. Multiple command buffers can be built in parallel by employing multiple threads within the application.

Command buffers submitted to different queues may execute in parallel or even out of order with respect to one another. Command buffers submitted to a single queue respect submission order, as described further in synchronization chapter. Command buffer execution by the device is also asynchronous to host execution. Once a command buffer is submitted to a queue, control may return to the application immediately. Synchronization between the device and host, and between different queues is the responsibility of the application.

#### 2.2.1. Queue Operation

Vulkan queues provide an interface to the execution engines of a device. Commands for these execution engines are recorded into command buffers ahead of execution time. These command buffers are then submitted to queues with a queue submission command for execution in a number of batches. Once submitted to a queue, these commands will begin and complete execution without further application intervention, though the order of this execution is dependent on a number of implicit and explicit ordering constraints.

Work is submitted to queues using queue submission commands that typically take the form `vkQueue*` (e.g. vkQueueSubmit, vkQueueBindSparse), and optionally take a list of semaphores upon which to wait before work begins and a list of semaphores to signal once work has completed. The work itself, as well as signaling and waiting on the semaphores are all queue operations.

Queue operations on different queues have no implicit ordering constraints, and may execute in any order. Explicit ordering constraints between queues can be expressed with semaphores and fences.

Command buffer submissions to a single queue respect submission order and other implicit ordering guarantees, but otherwise may overlap or execute out of order. Other types of batches and queue submissions against a single queue (e.g. sparse memory binding) have no implicit ordering constraints with any other queue submission or batch. Additional explicit ordering constraints between queue submissions and individual batches can be expressed with semaphores and fences.

Before a fence or semaphore is signaled, it is guaranteed that any previously submitted queue operations have completed execution, and that memory writes from those queue operations are available to future queue operations. Waiting on a signaled semaphore or fence guarantees that previous writes that are available are also visible to subsequent commands.

Command buffer boundaries, both between primary command buffers of the same or different batches or submissions as well as between primary and secondary command buffers, do not introduce any additional ordering constraints. In other words, submitting the set of command buffers (which can include executing secondary command buffers) between any semaphore or fence operations execute the recorded commands as if they had all been recorded into a single primary command buffer, except that the current state is reset on each boundary. Explicit ordering constraints can be expressed with explicit synchronization primitives.

There are a few implicit ordering guarantees between commands within a command buffer, but only covering a subset of execution. Additional explicit ordering constraints can be expressed with the various explicit synchronization primitives.

| Note Implementations have significant freedom to overlap execution of work submitted to a queue, and this is common due to deep pipelining and parallelism in Vulkan devices.

Commands recorded in command buffers either perform actions (draw, dispatch, clear, copy, query/timestamp operations, begin/end subpass operations), set state (bind pipelines, descriptor sets, and buffers, set dynamic state, push constants, set render pass/subpass state), or perform synchronization (set/wait events, pipeline barrier, render pass/subpass dependencies). Some commands perform more than one of these tasks. State setting commands update the current state of the command buffer. Some commands that perform actions (e.g. draw/dispatch) do so based on the current state set cumulatively since the start of the command buffer. The work involved in performing action commands is often allowed to overlap or to be reordered, but doing so must not alter the state to be used by each action command. In general, action commands are those commands that alter framebuffer attachments, read/write buffer or image memory, or write to query pools.

Synchronization commands introduce explicit execution and memory dependencies between two sets of action commands, where the second set of commands depends on the first set of commands. These dependencies enforce that both the execution of certain pipeline stages in the later set occur after the execution of certain stages in the source set, and that the effects of memory accesses performed by certain pipeline stages occur in order and are visible to each other. When not enforced by an explicit dependency or implicit ordering guarantees, action commands may overlap execution or execute out of order, and may not see the side effects of each other’s memory accesses.

The device executes queue operations asynchronously with respect to the host. Control is returned to an application immediately following command buffer submission to a queue. The application must synchronize work between the host and device as needed.

### 2.3. Object Model

The devices, queues, and other entities in Vulkan are represented by Vulkan objects. At the API level, all objects are referred to by handles. There are two classes of handles, dispatchable and non-dispatchable. Dispatchable handle types are a pointer to an opaque type. This pointer may be used by layers as part of intercepting API commands, and thus each API command takes a dispatchable type as its first parameter. Each object of a dispatchable type must have a unique handle value during its lifetime.

Non-dispatchable handle types are a 64-bit integer type whose meaning is implementation-dependent, and may encode object information directly in the handle rather than acting as a reference to an underlying object. Objects of a non-dispatchable type may not have unique handle values within a type or across types. If handle values are not unique, then destroying one such handle must not cause identical handles of other types to become invalid, and must not cause identical handles of the same type to become invalid if that handle value has been created more times than it has been destroyed.

All objects created or allocated from a `VkDevice` (i.e. with a `VkDevice` as the first parameter) are private to that device, and must not be used on other devices.

#### 2.3.1. Object Lifetime

Objects are created or allocated by `vkCreate*` and `vkAllocate*` commands, respectively. Once an object is created or allocated, its “structure” is considered to be immutable, though the contents of certain object types is still free to change. Objects are destroyed or freed by `vkDestroy*` and `vkFree*` commands, respectively.

Objects that are allocated (rather than created) take resources from an existing pool object or memory heap, and when freed return resources to that pool or heap. While object creation and destruction are generally expected to be low-frequency occurrences during runtime, allocating and freeing objects can occur at high frequency. Pool objects help accommodate improved performance of the allocations and frees.

It is an application’s responsibility to track the lifetime of Vulkan objects, and not to destroy them while they are still in use.

The ownership of application-owned memory is immediately acquired by any Vulkan command it is passed into. Ownership of such memory must be released back to the application at the end of the duration of the command, so that the application can alter or free this memory as soon as all the commands that acquired it have returned.

The following object types are consumed when they are passed into a Vulkan command and not further accessed by the objects they are used to create. They must not be destroyed in the duration of any API command they are passed into:

- `VkShaderModule`

- `VkPipelineCache`

- `VkValidationCacheEXT`

A `VkRenderPass` object passed as a parameter to create another object is not further accessed by that object after the duration of the command it is passed into. A `VkRenderPass` used in a command buffer follows the rules described below.

A `VkPipelineLayout` object must not be destroyed while any command buffer that uses it is in the recording state.

`VkDescriptorSetLayout` objects may be accessed by commands that operate on descriptor sets allocated using that layout, and those descriptor sets must not be updated with vkUpdateDescriptorSets after the descriptor set layout has been destroyed. Otherwise, a `VkDescriptorSetLayout` object passed as a parameter to create another object is not further accessed by that object after the duration of the command it is passed into.

The application must not destroy any other type of Vulkan object until all uses of that object by the device (such as via command buffer execution) have completed.

The following Vulkan objects must not be destroyed while any command buffers using the object are in the pending state:

- `VkEvent`

- `VkQueryPool`

- `VkBuffer`

- `VkBufferView`

- `VkImage`

- `VkImageView`

- `VkPipeline`

- `VkSampler`

- VkSamplerYcbcrConversion

- `VkDescriptorPool`

- `VkFramebuffer`

- `VkRenderPass`

- `VkCommandBuffer`

- `VkCommandPool`

- `VkDeviceMemory`

- `VkDescriptorSet`

- `VkIndirectCommandsLayoutNV`

Destroying these objects will move any command buffers that are in the recording or executable state, and are using those objects, to the invalid state.

The following Vulkan objects must not be destroyed while any queue is executing commands that use the object:

- `VkFence`

- `VkSemaphore`

- `VkCommandBuffer`

- `VkCommandPool`

In general, objects can be destroyed or freed in any order, even if the object being freed is involved in the use of another object (e.g. use of a resource in a view, use of a view in a descriptor set, use of an object in a command buffer, binding of a memory allocation to a resource), as long as any object that uses the freed object is not further used in any way except to be destroyed or to be reset in such a way that it no longer uses the other object (such as resetting a command buffer). If the object has been reset, then it can be used as if it never used the freed object. An exception to this is when there is a parent/child relationship between objects. In this case, the application must not destroy a parent object before its children, except when the parent is explicitly defined to free its children when it is destroyed (e.g. for pool objects, as defined below).

`VkCommandPool` objects are parents of `VkCommandBuffer` objects. `VkDescriptorPool` objects are parents of `VkDescriptorSet` objects. `VkDevice` objects are parents of many object types (all that take a `VkDevice` as a parameter to their creation).

The following Vulkan objects have specific restrictions for when they can be destroyed:

- `VkQueue` objects cannot be explicitly destroyed. Instead, they are implicitly destroyed when the `VkDevice` object they are retrieved from is destroyed.

- Destroying a pool object implicitly frees all objects allocated from that pool. Specifically, destroying `VkCommandPool` frees all `VkCommandBuffer` objects that were allocated from it, and destroying `VkDescriptorPool` frees all `VkDescriptorSet` objects that were allocated from it.

- `VkDevice` objects can be destroyed when all `VkQueue` objects retrieved from them are idle, and all objects created from them have been destroyed. This includes the following objects:

  - `VkFence`

  - `VkSemaphore`

  - `VkEvent`

  - `VkQueryPool`

  - `VkBuffer`

  - `VkBufferView`

  - `VkImage`

  - `VkImageView`

  - `VkShaderModule`

  - `VkPipelineCache`

  - `VkPipeline`

  - `VkPipelineLayout`

  - `VkSampler`

  - VkSamplerYcbcrConversion

  - `VkDescriptorSetLayout`

  - `VkDescriptorPool`

  - `VkFramebuffer`

  - `VkRenderPass`

  - `VkCommandPool`

  - `VkCommandBuffer`

  - `VkDeviceMemory`

  - `VkValidationCacheEXT`

- `VkPhysicalDevice` objects cannot be explicitly destroyed. Instead, they are implicitly destroyed when the `VkInstance` object they are retrieved from is destroyed.

- `VkInstance` objects can be destroyed once all `VkDevice` objects created from any of its `VkPhysicalDevice` objects have been destroyed.

- `VkPipeline` objects, that were created as pipeline library, can be destroyed once all `VkPipeline` objects that link with it have been destroyed.

- `VkPipeline` objects, that were referenced during the creation of graphics shader groups, can be destroyed once all `VkPipeline` objects that reference it have been destroyed.

#### 2.3.2. External Object Handles

As defined above, the scope of object handles created or allocated from a `VkDevice` is limited to that logical device. Objects which are not in scope are said to be external. To bring an external object into scope, an external handle must be exported from the object in the source scope and imported into the destination scope.

| Note The scope of external handles and their associated resources may vary according to their type, but they can generally be shared across process and API boundaries.

### 2.4. Application Binary Interface

The mechanism by which Vulkan is made available to applications is platform- or implementation- defined. On many platforms the C interface described in this Specification is provided by a shared library. Since shared libraries can be changed independently of the applications that use them, they present particular compatibility challenges, and this Specification places some requirements on them.

Shared library implementations must use the default Application Binary Interface (ABI) of the standard C compiler for the platform, or provide customized API headers that cause application code to use the implementation’s non-default ABI. An ABI in this context means the size, alignment, and layout of C data types; the procedure calling convention; and the naming convention for shared library symbols corresponding to C functions. Customizing the calling convention for a platform is usually accomplished by defining calling convention macros appropriately in `vk_platform.h`.

On platforms where Vulkan is provided as a shared library, library symbols beginning with “vk” and followed by a digit or uppercase letter are reserved for use by the implementation. Applications which use Vulkan must not provide definitions of these symbols. This allows the Vulkan shared library to be updated with additional symbols for new API versions or extensions without causing symbol conflicts with existing applications.

Shared library implementations should provide library symbols for commands in the highest version of this Specification they support, and for Window System Integration extensions relevant to the platform. They may also provide library symbols for commands defined by additional extensions.

| Note These requirements and recommendations are intended to allow implementors to take advantage of platform-specific conventions for SDKs, ABIs, library versioning mechanisms, etc. while still minimizing the code changes necessary to port applications or libraries between platforms. Platform vendors, or providers of the de facto standard Vulkan shared library for a platform, are encouraged to document what symbols the shared library provides and how it will be versioned when new symbols are added. Applications should only rely on shared library symbols for commands in the minimum core version required by the application. vkGetInstanceProcAddr and vkGetDeviceProcAddr should be used to obtain function pointers for commands in core versions beyond the application’s minimum required version.

### 2.5. Command Syntax and Duration

The Specification describes Vulkan commands as functions or procedures using C99 syntax. Language bindings for other languages such as C++ and JavaScript may allow for stricter parameter passing, or object-oriented interfaces.

Vulkan uses the standard C types for the base type of scalar parameters (e.g. types from `<stdint.h>`), with exceptions described below, or elsewhere in the text when appropriate:

`VkBool32` represents boolean `True` and `False` values, since C does not have a sufficiently portable built-in boolean type:

    typedef uint32_t VkBool32;

`VK_TRUE` represents a boolean True (integer 1) value, and `VK_FALSE` a boolean False (integer 0) value.

All values returned from a Vulkan implementation in a `VkBool32` will be either `VK_TRUE` or `VK_FALSE`.

Applications must not pass any other values than `VK_TRUE` or `VK_FALSE` into a Vulkan implementation where a `VkBool32` is expected.

`VkDeviceSize` represents device memory size and offset values:

    typedef uint64_t VkDeviceSize;

`VkDeviceAddress` represents device buffer address values:

    typedef uint64_t VkDeviceAddress;

Commands that create Vulkan objects are of the form `vkCreate*` and take `Vk*CreateInfo` structures with the parameters needed to create the object. These Vulkan objects are destroyed with commands of the form `vkDestroy*`.

The last in-parameter to each command that creates or destroys a Vulkan object is `pAllocator`. The `pAllocator` parameter can be set to a non-`NULL` value such that allocations for the given object are delegated to an application provided callback; refer to the Memory Allocation chapter for further details.

Commands that allocate Vulkan objects owned by pool objects are of the form `vkAllocate*`, and take `Vk*AllocateInfo` structures. These Vulkan objects are freed with commands of the form `vkFree*`. These objects do not take allocators; if host memory is needed, they will use the allocator that was specified when their parent pool was created.

Commands are recorded into a command buffer by calling API commands of the form `vkCmd*`. Each such command may have different restrictions on where it can be used: in a primary and/or secondary command buffer, inside and/or outside a render pass, and in one or more of the supported queue types. These restrictions are documented together with the definition of each such command.

The duration of a Vulkan command refers to the interval between calling the command and its return to the caller.

#### 2.5.1. Lifetime of Retrieved Results

Information is retrieved from the implementation with commands of the form `vkGet*` and `vkEnumerate*`.

Unless otherwise specified for an individual command, the results are invariant; that is, they will remain unchanged when retrieved again by calling the same command with the same parameters, so long as those parameters themselves all remain valid.

### 2.6. Threading Behavior

Vulkan is intended to provide scalable performance when used on multiple host threads. All commands support being called concurrently from multiple threads, but certain parameters, or components of parameters are defined to be externally synchronized. This means that the caller must guarantee that no more than one thread is using such a parameter at a given time.

More precisely, Vulkan commands use simple stores to update the state of Vulkan objects. A parameter declared as externally synchronized may have its contents updated at any time during the host execution of the command. If two commands operate on the same object and at least one of the commands declares the object to be externally synchronized, then the caller must guarantee not only that the commands do not execute simultaneously, but also that the two commands are separated by an appropriate memory barrier (if needed).

| Note Memory barriers are particularly relevant for hosts based on the ARM CPU architecture, which is more weakly ordered than many developers are accustomed to from x86/x64 programming. Fortunately, most higher-level synchronization primitives (like the pthread library) perform memory barriers as a part of mutual exclusion, so mutexing Vulkan objects via these primitives will have the desired effect.

Similarly the application must avoid any potential data hazard of application-owned memory that has its ownership temporarily acquired by a Vulkan command. While the ownership of application-owned memory remains acquired by a command the implementation may read the memory at any point, and it may write non-`const` qualified memory at any point. Parameters referring to non-`const` qualified application-owned memory are not marked explicitly as externally synchronized in the Specification.

If an application is using deferred host operations in a command, and that operation is successfully deferred, object parameters and application-owned memory passed to that command may be accessed at any time until the deferred operation is complete.

Many object types are immutable, meaning the objects cannot change once they have been created. These types of objects never need external synchronization, except that they must not be destroyed while they are in use on another thread. In certain special cases mutable object parameters are internally synchronized, making external synchronization unnecessary. Any command parameters that are not labeled as externally synchronized are either not mutated by the command or are internally synchronized. Additionally, certain objects related to a command’s parameters (e.g. command pools and descriptor pools) may be affected by a command, and must also be externally synchronized. These implicit parameters are documented as described below.

Parameters of commands that are externally synchronized are listed below.

Externally Synchronized Parameters

- The `instance` parameter in vkDestroyInstance

- The `device` parameter in vkDestroyDevice

- The `queue` parameter in vkQueueSubmit

- The `fence` parameter in vkQueueSubmit

- The `queue` parameter in vkQueueWaitIdle

- The `memory` parameter in vkFreeMemory

- The `memory` parameter in vkMapMemory

- The `memory` parameter in vkUnmapMemory

- The `buffer` parameter in vkBindBufferMemory

- The `image` parameter in vkBindImageMemory

- The `queue` parameter in vkQueueBindSparse

- The `fence` parameter in vkQueueBindSparse

- The `fence` parameter in vkDestroyFence

- The `semaphore` parameter in vkDestroySemaphore

- The `event` parameter in vkDestroyEvent

- The `event` parameter in vkSetEvent

- The `event` parameter in vkResetEvent

- The `queryPool` parameter in vkDestroyQueryPool

- The `buffer` parameter in vkDestroyBuffer

- The `bufferView` parameter in vkDestroyBufferView

- The `image` parameter in vkDestroyImage

- The `imageView` parameter in vkDestroyImageView

- The `shaderModule` parameter in vkDestroyShaderModule

- The `pipelineCache` parameter in vkDestroyPipelineCache

- The `dstCache` parameter in vkMergePipelineCaches

- The `pipeline` parameter in vkDestroyPipeline

- The `pipelineLayout` parameter in vkDestroyPipelineLayout

- The `sampler` parameter in vkDestroySampler

- The `descriptorSetLayout` parameter in vkDestroyDescriptorSetLayout

- The `descriptorPool` parameter in vkDestroyDescriptorPool

- The `descriptorPool` parameter in vkResetDescriptorPool

- The `descriptorPool` member of the `pAllocateInfo` parameter in vkAllocateDescriptorSets

- The `descriptorPool` parameter in vkFreeDescriptorSets

- The `framebuffer` parameter in vkDestroyFramebuffer

- The `renderPass` parameter in vkDestroyRenderPass

- The `commandPool` parameter in vkDestroyCommandPool

- The `commandPool` parameter in vkResetCommandPool

- The `commandPool` member of the `pAllocateInfo` parameter in vkAllocateCommandBuffers

- The `commandPool` parameter in vkFreeCommandBuffers

- The `commandBuffer` parameter in vkBeginCommandBuffer

- The `commandBuffer` parameter in vkEndCommandBuffer

- The `commandBuffer` parameter in vkResetCommandBuffer

- The `commandBuffer` parameter in vkCmdBindPipeline

- The `commandBuffer` parameter in vkCmdSetViewport

- The `commandBuffer` parameter in vkCmdSetScissor

- The `commandBuffer` parameter in vkCmdSetLineWidth

- The `commandBuffer` parameter in vkCmdSetDepthBias

- The `commandBuffer` parameter in vkCmdSetBlendConstants

- The `commandBuffer` parameter in vkCmdSetDepthBounds

- The `commandBuffer` parameter in vkCmdSetStencilCompareMask

- The `commandBuffer` parameter in vkCmdSetStencilWriteMask

- The `commandBuffer` parameter in vkCmdSetStencilReference

- The `commandBuffer` parameter in vkCmdBindDescriptorSets

- The `commandBuffer` parameter in vkCmdBindIndexBuffer

- The `commandBuffer` parameter in vkCmdBindVertexBuffers

- The `commandBuffer` parameter in vkCmdDraw

- The `commandBuffer` parameter in vkCmdDrawIndexed

- The `commandBuffer` parameter in vkCmdDrawIndirect

- The `commandBuffer` parameter in vkCmdDrawIndexedIndirect

- The `commandBuffer` parameter in vkCmdDispatch

- The `commandBuffer` parameter in vkCmdDispatchIndirect

- The `commandBuffer` parameter in vkCmdCopyBuffer

- The `commandBuffer` parameter in vkCmdCopyImage

- The `commandBuffer` parameter in vkCmdBlitImage

- The `commandBuffer` parameter in vkCmdCopyBufferToImage

- The `commandBuffer` parameter in vkCmdCopyImageToBuffer

- The `commandBuffer` parameter in vkCmdUpdateBuffer

- The `commandBuffer` parameter in vkCmdFillBuffer

- The `commandBuffer` parameter in vkCmdClearColorImage

- The `commandBuffer` parameter in vkCmdClearDepthStencilImage

- The `commandBuffer` parameter in vkCmdClearAttachments

- The `commandBuffer` parameter in vkCmdResolveImage

- The `commandBuffer` parameter in vkCmdSetEvent

- The `commandBuffer` parameter in vkCmdResetEvent

- The `commandBuffer` parameter in vkCmdWaitEvents

- The `commandBuffer` parameter in vkCmdPipelineBarrier

- The `commandBuffer` parameter in vkCmdBeginQuery

- The `commandBuffer` parameter in vkCmdEndQuery

- The `commandBuffer` parameter in vkCmdResetQueryPool

- The `commandBuffer` parameter in vkCmdWriteTimestamp

- The `commandBuffer` parameter in vkCmdCopyQueryPoolResults

- The `commandBuffer` parameter in vkCmdPushConstants

- The `commandBuffer` parameter in vkCmdBeginRenderPass

- The `commandBuffer` parameter in vkCmdNextSubpass

- The `commandBuffer` parameter in vkCmdEndRenderPass

- The `commandBuffer` parameter in vkCmdExecuteCommands

- The `commandBuffer` parameter in vkCmdSetDeviceMask

- The `commandBuffer` parameter in vkCmdDispatchBase

- The `commandPool` parameter in vkTrimCommandPool

- The `ycbcrConversion` parameter in vkDestroySamplerYcbcrConversion

- The `descriptorUpdateTemplate` parameter in vkDestroyDescriptorUpdateTemplate

- The `descriptorSet` parameter in vkUpdateDescriptorSetWithTemplate

- The `commandBuffer` parameter in vkCmdDrawIndirectCount

- The `commandBuffer` parameter in vkCmdDrawIndexedIndirectCount

- The `commandBuffer` parameter in vkCmdBeginRenderPass2

- The `commandBuffer` parameter in vkCmdNextSubpass2

- The `commandBuffer` parameter in vkCmdEndRenderPass2

- The `surface` parameter in vkDestroySurfaceKHR

- The `surface` member of the `pCreateInfo` parameter in vkCreateSwapchainKHR

- The `oldSwapchain` member of the `pCreateInfo` parameter in vkCreateSwapchainKHR

- The `swapchain` parameter in vkDestroySwapchainKHR

- The `swapchain` parameter in vkAcquireNextImageKHR

- The `semaphore` parameter in vkAcquireNextImageKHR

- The `fence` parameter in vkAcquireNextImageKHR

- The `queue` parameter in vkQueuePresentKHR

- The `surface` parameter in vkGetDeviceGroupSurfacePresentModesKHR

- The `surface` parameter in vkGetPhysicalDevicePresentRectanglesKHR

- The `display` parameter in vkCreateDisplayModeKHR

- The `mode` parameter in vkGetDisplayPlaneCapabilitiesKHR

- The `commandBuffer` parameter in vkCmdSetDeviceMaskKHR

- The `commandBuffer` parameter in vkCmdDispatchBaseKHR

- The `commandPool` parameter in vkTrimCommandPoolKHR

- The `commandBuffer` parameter in vkCmdPushDescriptorSetKHR

- The `commandBuffer` parameter in vkCmdPushDescriptorSetWithTemplateKHR

- The `descriptorUpdateTemplate` parameter in vkDestroyDescriptorUpdateTemplateKHR

- The `descriptorSet` parameter in vkUpdateDescriptorSetWithTemplateKHR

- The `commandBuffer` parameter in vkCmdBeginRenderPass2KHR

- The `commandBuffer` parameter in vkCmdNextSubpass2KHR

- The `commandBuffer` parameter in vkCmdEndRenderPass2KHR

- The `swapchain` parameter in vkGetSwapchainStatusKHR

- The `ycbcrConversion` parameter in vkDestroySamplerYcbcrConversionKHR

- The `commandBuffer` parameter in vkCmdDrawIndirectCountKHR

- The `commandBuffer` parameter in vkCmdDrawIndexedIndirectCountKHR

- The `callback` parameter in vkDestroyDebugReportCallbackEXT

- The `object` member of the `pTagInfo` parameter in vkDebugMarkerSetObjectTagEXT

- The `object` member of the `pNameInfo` parameter in vkDebugMarkerSetObjectNameEXT

- The `commandBuffer` parameter in vkCmdBindTransformFeedbackBuffersEXT

- The `commandBuffer` parameter in vkCmdBeginTransformFeedbackEXT

- The `commandBuffer` parameter in vkCmdEndTransformFeedbackEXT

- The `commandBuffer` parameter in vkCmdBeginQueryIndexedEXT

- The `commandBuffer` parameter in vkCmdEndQueryIndexedEXT

- The `commandBuffer` parameter in vkCmdDrawIndirectByteCountEXT

- The `commandBuffer` parameter in vkCmdDrawIndirectCountAMD

- The `commandBuffer` parameter in vkCmdDrawIndexedIndirectCountAMD

- The `commandBuffer` parameter in vkCmdBeginConditionalRenderingEXT

- The `commandBuffer` parameter in vkCmdEndConditionalRenderingEXT

- The `commandBuffer` parameter in vkCmdSetViewportWScalingNV

- The `swapchain` parameter in vkGetRefreshCycleDurationGOOGLE

- The `swapchain` parameter in vkGetPastPresentationTimingGOOGLE

- The `commandBuffer` parameter in vkCmdSetDiscardRectangleEXT

- The `objectHandle` member of the `pNameInfo` parameter in vkSetDebugUtilsObjectNameEXT

- The `objectHandle` member of the `pTagInfo` parameter in vkSetDebugUtilsObjectTagEXT

- The `messenger` parameter in vkDestroyDebugUtilsMessengerEXT

- The `commandBuffer` parameter in vkCmdSetSampleLocationsEXT

- The `validationCache` parameter in vkDestroyValidationCacheEXT

- The `dstCache` parameter in vkMergeValidationCachesEXT

- The `commandBuffer` parameter in vkCmdBindShadingRateImageNV

- The `commandBuffer` parameter in vkCmdSetViewportShadingRatePaletteNV

- The `commandBuffer` parameter in vkCmdSetCoarseSampleOrderNV

- The `commandBuffer` parameter in vkCmdWriteBufferMarkerAMD

- The `commandBuffer` parameter in vkCmdDrawMeshTasksNV

- The `commandBuffer` parameter in vkCmdDrawMeshTasksIndirectNV

- The `commandBuffer` parameter in vkCmdDrawMeshTasksIndirectCountNV

- The `commandBuffer` parameter in vkCmdSetExclusiveScissorNV

- The `commandBuffer` parameter in vkCmdSetLineStippleEXT

- The `commandBuffer` parameter in vkCmdPreprocessGeneratedCommandsNV

- The `commandBuffer` parameter in vkCmdExecuteGeneratedCommandsNV

- The `commandBuffer` parameter in vkCmdBindPipelineShaderGroupNV

For `VkPipelineCache` objects created with `flags` containing VK_PIPELINE_CACHE_CREATE_EXTERNALLY_SYNCHRONIZED_BIT_EXT, the above table is extended with the `pipelineCache` parameter to `vkCreate*Pipelines` being externally synchronized.

There are also a few instances where a command can take in a user allocated list whose contents are externally synchronized parameters. In these cases, the caller must guarantee that at most one thread is using a given element within the list at a given time. These parameters are listed below.

Externally Synchronized Parameter Lists

- The `buffer` member of each element of the `pBufferBinds` member of each element of the `pBindInfo` parameter in vkQueueBindSparse

- The `image` member of each element of the `pImageOpaqueBinds` member of each element of the `pBindInfo` parameter in vkQueueBindSparse

- The `image` member of each element of the `pImageBinds` member of each element of the `pBindInfo` parameter in vkQueueBindSparse

- Each element of the `pFences` parameter in vkResetFences

- Each element of the `pDescriptorSets` parameter in vkFreeDescriptorSets

- The `dstSet` member of each element of the `pDescriptorWrites` parameter in vkUpdateDescriptorSets

- The `dstSet` member of each element of the `pDescriptorCopies` parameter in vkUpdateDescriptorSets

- Each element of the `pCommandBuffers` parameter in vkFreeCommandBuffers

- Each element of the `pWaitSemaphores` member of the `pPresentInfo` parameter in vkQueuePresentKHR

- Each element of the `pSwapchains` member of the `pPresentInfo` parameter in vkQueuePresentKHR

- The `surface` member of each element of the `pCreateInfos` parameter in vkCreateSharedSwapchainsKHR

- The `oldSwapchain` member of each element of the `pCreateInfos` parameter in vkCreateSharedSwapchainsKHR

In addition, there are some implicit parameters that need to be externally synchronized. For example, all `commandBuffer` parameters that need to be externally synchronized imply that the `commandPool` that was passed in when creating that command buffer also needs to be externally synchronized. The implicit parameters and their associated object are listed below.

Implicit Externally Synchronized Parameters

- All `VkQueue` objects created from `device` in vkDeviceWaitIdle

- Any `VkDescriptorSet` objects allocated from `descriptorPool` in vkResetDescriptorPool

- The `VkCommandPool` that `commandBuffer` was allocated from in vkBeginCommandBuffer

- The `VkCommandPool` that `commandBuffer` was allocated from in vkEndCommandBuffer

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdBindPipeline

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdSetViewport

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdSetScissor

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdSetLineWidth

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdSetDepthBias

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdSetBlendConstants

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdSetDepthBounds

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdSetStencilCompareMask

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdSetStencilWriteMask

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdSetStencilReference

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdBindDescriptorSets

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdBindIndexBuffer

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdBindVertexBuffers

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdDraw

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdDrawIndexed

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdDrawIndirect

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdDrawIndexedIndirect

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdDispatch

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdDispatchIndirect

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdCopyBuffer

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdCopyImage

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdBlitImage

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdCopyBufferToImage

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdCopyImageToBuffer

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdUpdateBuffer

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdFillBuffer

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdClearColorImage

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdClearDepthStencilImage

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdClearAttachments

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdResolveImage

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdSetEvent

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdResetEvent

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdWaitEvents

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdPipelineBarrier

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdBeginQuery

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdEndQuery

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdResetQueryPool

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdWriteTimestamp

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdCopyQueryPoolResults

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdPushConstants

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdBeginRenderPass

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdNextSubpass

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdEndRenderPass

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdExecuteCommands

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdSetDeviceMask

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdDispatchBase

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdDrawIndirectCount

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdDrawIndexedIndirectCount

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdBeginRenderPass2

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdNextSubpass2

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdEndRenderPass2

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdSetDeviceMaskKHR

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdDispatchBaseKHR

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdPushDescriptorSetKHR

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdPushDescriptorSetWithTemplateKHR

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdBeginRenderPass2KHR

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdNextSubpass2KHR

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdEndRenderPass2KHR

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdDrawIndirectCountKHR

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdDrawIndexedIndirectCountKHR

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdDebugMarkerBeginEXT

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdDebugMarkerEndEXT

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdDebugMarkerInsertEXT

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdBindTransformFeedbackBuffersEXT

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdBeginTransformFeedbackEXT

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdEndTransformFeedbackEXT

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdBeginQueryIndexedEXT

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdEndQueryIndexedEXT

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdDrawIndirectByteCountEXT

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdDrawIndirectCountAMD

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdDrawIndexedIndirectCountAMD

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdBeginConditionalRenderingEXT

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdEndConditionalRenderingEXT

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdSetViewportWScalingNV

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdSetDiscardRectangleEXT

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdBeginDebugUtilsLabelEXT

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdEndDebugUtilsLabelEXT

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdInsertDebugUtilsLabelEXT

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdSetSampleLocationsEXT

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdBindShadingRateImageNV

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdSetViewportShadingRatePaletteNV

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdSetCoarseSampleOrderNV

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdBuildAccelerationStructureNV

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdCopyAccelerationStructureNV

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdTraceRaysNV

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdWriteAccelerationStructuresPropertiesKHR

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdWriteAccelerationStructuresPropertiesNV

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdWriteBufferMarkerAMD

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdDrawMeshTasksNV

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdDrawMeshTasksIndirectNV

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdDrawMeshTasksIndirectCountNV

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdSetExclusiveScissorNV

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdSetCheckpointNV

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdSetPerformanceMarkerINTEL

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdSetPerformanceStreamMarkerINTEL

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdSetPerformanceOverrideINTEL

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdSetLineStippleEXT

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdPreprocessGeneratedCommandsNV

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdExecuteGeneratedCommandsNV

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdBindPipelineShaderGroupNV

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdBuildAccelerationStructureKHR

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdBuildAccelerationStructureIndirectKHR

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdCopyAccelerationStructureKHR

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdCopyAccelerationStructureToMemoryKHR

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdCopyMemoryToAccelerationStructureKHR

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdTraceRaysKHR

- The `VkCommandPool` that `commandBuffer` was allocated from, in vkCmdTraceRaysIndirectKHR

### 2.7. Errors

Vulkan is a layered API. The lowest layer is the core Vulkan layer, as defined by this Specification. The application can use additional layers above the core for debugging, validation, and other purposes.

One of the core principles of Vulkan is that building and submitting command buffers should be highly efficient. Thus error checking and validation of state in the core layer is minimal, although more rigorous validation can be enabled through the use of layers.

The core layer assumes applications are using the API correctly. Except as documented elsewhere in the Specification, the behavior of the core layer to an application using the API incorrectly is undefined, and may include program termination. However, implementations must ensure that incorrect usage by an application does not affect the integrity of the operating system, the Vulkan implementation, or other Vulkan client applications in the system. In particular, any guarantees made by an operating system about whether memory from one process can be visible to another process or not must not be violated by a Vulkan implementation for any memory allocation. Vulkan implementations are not required to make additional security or integrity guarantees beyond those provided by the OS unless explicitly directed by the application’s use of a particular feature or extension.

| Note For instance, if an operating system guarantees that data in all its memory allocations are set to zero when newly allocated, the Vulkan implementation must make the same guarantees for any allocations it controls (e.g. VkDeviceMemory). Similarly, if an operating system guarantees that use-after-free of host allocations will not result in values written by another process becoming visible, the same guarantees must be made by the Vulkan implementation for device memory.

If the protected memory feature is supported, the implementation provides additional guarantees when invalid usage occurs to prevent values in protected memory from being accessed or inferred outside of protected operations, as described in Protected Memory Access Rules.

Validation of correct API usage is left to validation layers. Applications should be developed with validation layers enabled, to help catch and eliminate errors. Once validated, released applications should not enable validation layers by default.

#### 2.7.1. Valid Usage

Valid usage defines a set of conditions which must be met in order to achieve well-defined run-time behavior in an application. These conditions depend only on Vulkan state, and the parameters or objects whose usage is constrained by the condition.

Some valid usage conditions have dependencies on run-time limits or feature availability. It is possible to validate these conditions against Vulkan’s minimum supported values for these limits and features, or some subset of other known values.

Valid usage conditions do not cover conditions where well-defined behavior (including returning an error code) exists.

Valid usage conditions should apply to the command or structure where complete information about the condition would be known during execution of an application. This is such that a validation layer or linter can be written directly against these statements at the point they are specified.

| Note This does lead to some non-obvious places for valid usage statements. For instance, the valid values for a structure might depend on a separate value in the calling command. In this case, the structure itself will not reference this valid usage as it is impossible to determine validity from the structure that it is invalid - instead this valid usage would be attached to the calling command. Another example is draw state - the state setters are independent, and can cause a legitimately invalid state configuration between draw calls; so the valid usage statements are attached to the place where all state needs to be valid - at the draw command.

Valid usage conditions are described in a block labelled “Valid Usage” following each command or structure they apply to.

#### 2.7.2. Implicit Valid Usage

Some valid usage conditions apply to all commands and structures in the API, unless explicitly denoted otherwise for a specific command or structure. These conditions are considered implicit, and are described in a block labelled “Valid Usage (Implicit)” following each command or structure they apply to. Implicit valid usage conditions are described in detail below.

##### Valid Usage for Object Handles

Any input parameter to a command that is an object handle must be a valid object handle, unless otherwise specified. An object handle is valid if:

- It has been created or allocated by a previous, successful call to the API. Such calls are noted in the Specification.

- It has not been deleted or freed by a previous call to the API. Such calls are noted in the Specification.

- Any objects used by that object, either as part of creation or execution, must also be valid.

The reserved values VK_NULL_HANDLE and `NULL` can be used in place of valid non-dispatchable handles and dispatchable handles, respectively, when explicitly called out in the Specification. Any command that creates an object successfully must not return these values. It is valid to pass these values to `vkDestroy*` or `vkFree*` commands, which will silently ignore these values.

##### Valid Usage for Pointers

Any parameter that is a pointer must be a valid pointer only if it is explicitly called out by a Valid Usage statement.

A pointer is “valid” if it points at memory containing values of the number and type(s) expected by the command, and all fundamental types accessed through the pointer (e.g. as elements of an array or as members of a structure) satisfy the alignment requirements of the host processor.

##### Valid Usage for Strings

Any parameter that is a pointer to `char` must be a finite sequence of values terminated by a null character, or if explicitly called out in the Specification, can be `NULL`.

##### Valid Usage for Enumerated Types

Any parameter of an enumerated type must be a valid enumerant for that type. A enumerant is valid if:

- The enumerant is defined as part of the enumerated type.

- The enumerant is not one of the special values defined for the enumerated type, which are suffixed with `_BEGIN_RANGE`, `_END_RANGE`, `_RANGE_SIZE` or `_MAX_ENUM`1.

  1

    The meaning of these special tokens is not exposed in the Vulkan Specification. They are not part of the API, and they should not be used by applications. Their original intended use was for internal consumption by Vulkan implementations. Even that use will no longer be supported in the future, but they will be retained for backwards compatibility reasons.

Any enumerated type returned from a query command or otherwise output from Vulkan to the application must not have a reserved value. Reserved values are values not defined by any extension for that enumerated type.

| Note This language is intended to accommodate cases such as “hidden” extensions known only to driver internals, or layers enabling extensions without knowledge of the application, without allowing return of values not defined by any extension.

##### Valid Usage for Flags

A collection of flags is represented by a bitmask using the type `VkFlags`:

    typedef uint32_t VkFlags;

Bitmasks are passed to many commands and structures to compactly represent options, but `VkFlags` is not used directly in the API. Instead, a `Vk*Flags` type which is an alias of `VkFlags`, and whose name matches the corresponding `Vk*FlagBits` that are valid for that type, is used.

Any `Vk*Flags` member or parameter used in the API as an input must be a valid combination of bit flags. A valid combination is either zero or the bitwise OR of valid bit flags. A bit flag is valid if:

- The bit flag is defined as part of the `Vk*FlagBits` type, where the bits type is obtained by taking the flag type and replacing the trailing `Flags` with `FlagBits`. For example, a flag value of type VkColorComponentFlags must contain only bit flags defined by VkColorComponentFlagBits.

- The flag is allowed in the context in which it is being used. For example, in some cases, certain bit flags or combinations of bit flags are mutually exclusive.

Any `Vk*Flags` member or parameter returned from a query command or otherwise output from Vulkan to the application may contain bit flags undefined in its corresponding `Vk*FlagBits` type. An application cannot rely on the state of these unspecified bits.

Only the low-order 31 bits (bit positions zero through 30) are available for use as flag bits.

| Note This restriction is due to poorly defined behavior by C compilers given a C enumerant value of `0x80000000`. In some cases adding this enumerant value may increase the size of the underlying `Vk*FlagBits` type, breaking the ABI.

##### Valid Usage for Structure Types

Any parameter that is a structure containing a `sType` member must have a value of `sType` which is a valid VkStructureType value matching the type of the structure.

Structure types supported by the Vulkan API include:

    typedef enum VkStructureType {
        VK_STRUCTURE_TYPE_APPLICATION_INFO = 0,
        VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO = 1,
        VK_STRUCTURE_TYPE_DEVICE_QUEUE_CREATE_INFO = 2,
        VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO = 3,
        VK_STRUCTURE_TYPE_SUBMIT_INFO = 4,
        VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO = 5,
        VK_STRUCTURE_TYPE_MAPPED_MEMORY_RANGE = 6,
        VK_STRUCTURE_TYPE_BIND_SPARSE_INFO = 7,
        VK_STRUCTURE_TYPE_FENCE_CREATE_INFO = 8,
        VK_STRUCTURE_TYPE_SEMAPHORE_CREATE_INFO = 9,
        VK_STRUCTURE_TYPE_EVENT_CREATE_INFO = 10,
        VK_STRUCTURE_TYPE_QUERY_POOL_CREATE_INFO = 11,
        VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO = 12,
        VK_STRUCTURE_TYPE_BUFFER_VIEW_CREATE_INFO = 13,
        VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO = 14,
        VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO = 15,
        VK_STRUCTURE_TYPE_SHADER_MODULE_CREATE_INFO = 16,
        VK_STRUCTURE_TYPE_PIPELINE_CACHE_CREATE_INFO = 17,
        VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO = 18,
        VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_STATE_CREATE_INFO = 19,
        VK_STRUCTURE_TYPE_PIPELINE_INPUT_ASSEMBLY_STATE_CREATE_INFO = 20,
        VK_STRUCTURE_TYPE_PIPELINE_TESSELLATION_STATE_CREATE_INFO = 21,
        VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO = 22,
        VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_CREATE_INFO = 23,
        VK_STRUCTURE_TYPE_PIPELINE_MULTISAMPLE_STATE_CREATE_INFO = 24,
        VK_STRUCTURE_TYPE_PIPELINE_DEPTH_STENCIL_STATE_CREATE_INFO = 25,
        VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_STATE_CREATE_INFO = 26,
        VK_STRUCTURE_TYPE_PIPELINE_DYNAMIC_STATE_CREATE_INFO = 27,
        VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_CREATE_INFO = 28,
        VK_STRUCTURE_TYPE_COMPUTE_PIPELINE_CREATE_INFO = 29,
        VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO = 30,
        VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO = 31,
        VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO = 32,
        VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO = 33,
        VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO = 34,
        VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET = 35,
        VK_STRUCTURE_TYPE_COPY_DESCRIPTOR_SET = 36,
        VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO = 37,
        VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO = 38,
        VK_STRUCTURE_TYPE_COMMAND_POOL_CREATE_INFO = 39,
        VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO = 40,
        VK_STRUCTURE_TYPE_COMMAND_BUFFER_INHERITANCE_INFO = 41,
        VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO = 42,
        VK_STRUCTURE_TYPE_RENDER_PASS_BEGIN_INFO = 43,
        VK_STRUCTURE_TYPE_BUFFER_MEMORY_BARRIER = 44,
        VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER = 45,
        VK_STRUCTURE_TYPE_MEMORY_BARRIER = 46,
        VK_STRUCTURE_TYPE_LOADER_INSTANCE_CREATE_INFO = 47,
        VK_STRUCTURE_TYPE_LOADER_DEVICE_CREATE_INFO = 48,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SUBGROUP_PROPERTIES = 1000094000,
        VK_STRUCTURE_TYPE_BIND_BUFFER_MEMORY_INFO = 1000157000,
        VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_INFO = 1000157001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_16BIT_STORAGE_FEATURES = 1000083000,
        VK_STRUCTURE_TYPE_MEMORY_DEDICATED_REQUIREMENTS = 1000127000,
        VK_STRUCTURE_TYPE_MEMORY_DEDICATED_ALLOCATE_INFO = 1000127001,
        VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_FLAGS_INFO = 1000060000,
        VK_STRUCTURE_TYPE_DEVICE_GROUP_RENDER_PASS_BEGIN_INFO = 1000060003,
        VK_STRUCTURE_TYPE_DEVICE_GROUP_COMMAND_BUFFER_BEGIN_INFO = 1000060004,
        VK_STRUCTURE_TYPE_DEVICE_GROUP_SUBMIT_INFO = 1000060005,
        VK_STRUCTURE_TYPE_DEVICE_GROUP_BIND_SPARSE_INFO = 1000060006,
        VK_STRUCTURE_TYPE_BIND_BUFFER_MEMORY_DEVICE_GROUP_INFO = 1000060013,
        VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_DEVICE_GROUP_INFO = 1000060014,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_GROUP_PROPERTIES = 1000070000,
        VK_STRUCTURE_TYPE_DEVICE_GROUP_DEVICE_CREATE_INFO = 1000070001,
        VK_STRUCTURE_TYPE_BUFFER_MEMORY_REQUIREMENTS_INFO_2 = 1000146000,
        VK_STRUCTURE_TYPE_IMAGE_MEMORY_REQUIREMENTS_INFO_2 = 1000146001,
        VK_STRUCTURE_TYPE_IMAGE_SPARSE_MEMORY_REQUIREMENTS_INFO_2 = 1000146002,
        VK_STRUCTURE_TYPE_MEMORY_REQUIREMENTS_2 = 1000146003,
        VK_STRUCTURE_TYPE_SPARSE_IMAGE_MEMORY_REQUIREMENTS_2 = 1000146004,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FEATURES_2 = 1000059000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROPERTIES_2 = 1000059001,
        VK_STRUCTURE_TYPE_FORMAT_PROPERTIES_2 = 1000059002,
        VK_STRUCTURE_TYPE_IMAGE_FORMAT_PROPERTIES_2 = 1000059003,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGE_FORMAT_INFO_2 = 1000059004,
        VK_STRUCTURE_TYPE_QUEUE_FAMILY_PROPERTIES_2 = 1000059005,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_PROPERTIES_2 = 1000059006,
        VK_STRUCTURE_TYPE_SPARSE_IMAGE_FORMAT_PROPERTIES_2 = 1000059007,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SPARSE_IMAGE_FORMAT_INFO_2 = 1000059008,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_POINT_CLIPPING_PROPERTIES = 1000117000,
        VK_STRUCTURE_TYPE_RENDER_PASS_INPUT_ATTACHMENT_ASPECT_CREATE_INFO = 1000117001,
        VK_STRUCTURE_TYPE_IMAGE_VIEW_USAGE_CREATE_INFO = 1000117002,
        VK_STRUCTURE_TYPE_PIPELINE_TESSELLATION_DOMAIN_ORIGIN_STATE_CREATE_INFO = 1000117003,
        VK_STRUCTURE_TYPE_RENDER_PASS_MULTIVIEW_CREATE_INFO = 1000053000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_FEATURES = 1000053001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_PROPERTIES = 1000053002,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VARIABLE_POINTERS_FEATURES = 1000120000,
        VK_STRUCTURE_TYPE_PROTECTED_SUBMIT_INFO = 1000145000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROTECTED_MEMORY_FEATURES = 1000145001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROTECTED_MEMORY_PROPERTIES = 1000145002,
        VK_STRUCTURE_TYPE_DEVICE_QUEUE_INFO_2 = 1000145003,
        VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_CREATE_INFO = 1000156000,
        VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_INFO = 1000156001,
        VK_STRUCTURE_TYPE_BIND_IMAGE_PLANE_MEMORY_INFO = 1000156002,
        VK_STRUCTURE_TYPE_IMAGE_PLANE_MEMORY_REQUIREMENTS_INFO = 1000156003,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SAMPLER_YCBCR_CONVERSION_FEATURES = 1000156004,
        VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_IMAGE_FORMAT_PROPERTIES = 1000156005,
        VK_STRUCTURE_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_CREATE_INFO = 1000085000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_IMAGE_FORMAT_INFO = 1000071000,
        VK_STRUCTURE_TYPE_EXTERNAL_IMAGE_FORMAT_PROPERTIES = 1000071001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_BUFFER_INFO = 1000071002,
        VK_STRUCTURE_TYPE_EXTERNAL_BUFFER_PROPERTIES = 1000071003,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_ID_PROPERTIES = 1000071004,
        VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_BUFFER_CREATE_INFO = 1000072000,
        VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_IMAGE_CREATE_INFO = 1000072001,
        VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO = 1000072002,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_FENCE_INFO = 1000112000,
        VK_STRUCTURE_TYPE_EXTERNAL_FENCE_PROPERTIES = 1000112001,
        VK_STRUCTURE_TYPE_EXPORT_FENCE_CREATE_INFO = 1000113000,
        VK_STRUCTURE_TYPE_EXPORT_SEMAPHORE_CREATE_INFO = 1000077000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_SEMAPHORE_INFO = 1000076000,
        VK_STRUCTURE_TYPE_EXTERNAL_SEMAPHORE_PROPERTIES = 1000076001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MAINTENANCE_3_PROPERTIES = 1000168000,
        VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_SUPPORT = 1000168001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_DRAW_PARAMETERS_FEATURES = 1000063000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VULKAN_1_1_FEATURES = 49,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VULKAN_1_1_PROPERTIES = 50,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VULKAN_1_2_FEATURES = 51,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VULKAN_1_2_PROPERTIES = 52,
        VK_STRUCTURE_TYPE_IMAGE_FORMAT_LIST_CREATE_INFO = 1000147000,
        VK_STRUCTURE_TYPE_ATTACHMENT_DESCRIPTION_2 = 1000109000,
        VK_STRUCTURE_TYPE_ATTACHMENT_REFERENCE_2 = 1000109001,
        VK_STRUCTURE_TYPE_SUBPASS_DESCRIPTION_2 = 1000109002,
        VK_STRUCTURE_TYPE_SUBPASS_DEPENDENCY_2 = 1000109003,
        VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO_2 = 1000109004,
        VK_STRUCTURE_TYPE_SUBPASS_BEGIN_INFO = 1000109005,
        VK_STRUCTURE_TYPE_SUBPASS_END_INFO = 1000109006,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_8BIT_STORAGE_FEATURES = 1000177000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DRIVER_PROPERTIES = 1000196000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_ATOMIC_INT64_FEATURES = 1000180000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_FLOAT16_INT8_FEATURES = 1000082000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FLOAT_CONTROLS_PROPERTIES = 1000197000,
        VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_BINDING_FLAGS_CREATE_INFO = 1000161000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_FEATURES = 1000161001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_PROPERTIES = 1000161002,
        VK_STRUCTURE_TYPE_DESCRIPTOR_SET_VARIABLE_DESCRIPTOR_COUNT_ALLOCATE_INFO = 1000161003,
        VK_STRUCTURE_TYPE_DESCRIPTOR_SET_VARIABLE_DESCRIPTOR_COUNT_LAYOUT_SUPPORT = 1000161004,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DEPTH_STENCIL_RESOLVE_PROPERTIES = 1000199000,
        VK_STRUCTURE_TYPE_SUBPASS_DESCRIPTION_DEPTH_STENCIL_RESOLVE = 1000199001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SCALAR_BLOCK_LAYOUT_FEATURES = 1000221000,
        VK_STRUCTURE_TYPE_IMAGE_STENCIL_USAGE_CREATE_INFO = 1000246000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SAMPLER_FILTER_MINMAX_PROPERTIES = 1000130000,
        VK_STRUCTURE_TYPE_SAMPLER_REDUCTION_MODE_CREATE_INFO = 1000130001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VULKAN_MEMORY_MODEL_FEATURES = 1000211000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGELESS_FRAMEBUFFER_FEATURES = 1000108000,
        VK_STRUCTURE_TYPE_FRAMEBUFFER_ATTACHMENTS_CREATE_INFO = 1000108001,
        VK_STRUCTURE_TYPE_FRAMEBUFFER_ATTACHMENT_IMAGE_INFO = 1000108002,
        VK_STRUCTURE_TYPE_RENDER_PASS_ATTACHMENT_BEGIN_INFO = 1000108003,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_UNIFORM_BUFFER_STANDARD_LAYOUT_FEATURES = 1000253000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_SUBGROUP_EXTENDED_TYPES_FEATURES = 1000175000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SEPARATE_DEPTH_STENCIL_LAYOUTS_FEATURES = 1000241000,
        VK_STRUCTURE_TYPE_ATTACHMENT_REFERENCE_STENCIL_LAYOUT = 1000241001,
        VK_STRUCTURE_TYPE_ATTACHMENT_DESCRIPTION_STENCIL_LAYOUT = 1000241002,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_HOST_QUERY_RESET_FEATURES = 1000261000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TIMELINE_SEMAPHORE_FEATURES = 1000207000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TIMELINE_SEMAPHORE_PROPERTIES = 1000207001,
        VK_STRUCTURE_TYPE_SEMAPHORE_TYPE_CREATE_INFO = 1000207002,
        VK_STRUCTURE_TYPE_TIMELINE_SEMAPHORE_SUBMIT_INFO = 1000207003,
        VK_STRUCTURE_TYPE_SEMAPHORE_WAIT_INFO = 1000207004,
        VK_STRUCTURE_TYPE_SEMAPHORE_SIGNAL_INFO = 1000207005,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_BUFFER_DEVICE_ADDRESS_FEATURES = 1000257000,
        VK_STRUCTURE_TYPE_BUFFER_DEVICE_ADDRESS_INFO = 1000244001,
        VK_STRUCTURE_TYPE_BUFFER_OPAQUE_CAPTURE_ADDRESS_CREATE_INFO = 1000257002,
        VK_STRUCTURE_TYPE_MEMORY_OPAQUE_CAPTURE_ADDRESS_ALLOCATE_INFO = 1000257003,
        VK_STRUCTURE_TYPE_DEVICE_MEMORY_OPAQUE_CAPTURE_ADDRESS_INFO = 1000257004,
        VK_STRUCTURE_TYPE_SWAPCHAIN_CREATE_INFO_KHR = 1000001000,
        VK_STRUCTURE_TYPE_PRESENT_INFO_KHR = 1000001001,
        VK_STRUCTURE_TYPE_DEVICE_GROUP_PRESENT_CAPABILITIES_KHR = 1000060007,
        VK_STRUCTURE_TYPE_IMAGE_SWAPCHAIN_CREATE_INFO_KHR = 1000060008,
        VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_SWAPCHAIN_INFO_KHR = 1000060009,
        VK_STRUCTURE_TYPE_ACQUIRE_NEXT_IMAGE_INFO_KHR = 1000060010,
        VK_STRUCTURE_TYPE_DEVICE_GROUP_PRESENT_INFO_KHR = 1000060011,
        VK_STRUCTURE_TYPE_DEVICE_GROUP_SWAPCHAIN_CREATE_INFO_KHR = 1000060012,
        VK_STRUCTURE_TYPE_DISPLAY_MODE_CREATE_INFO_KHR = 1000002000,
        VK_STRUCTURE_TYPE_DISPLAY_SURFACE_CREATE_INFO_KHR = 1000002001,
        VK_STRUCTURE_TYPE_DISPLAY_PRESENT_INFO_KHR = 1000003000,
        VK_STRUCTURE_TYPE_XLIB_SURFACE_CREATE_INFO_KHR = 1000004000,
        VK_STRUCTURE_TYPE_XCB_SURFACE_CREATE_INFO_KHR = 1000005000,
        VK_STRUCTURE_TYPE_WAYLAND_SURFACE_CREATE_INFO_KHR = 1000006000,
        VK_STRUCTURE_TYPE_ANDROID_SURFACE_CREATE_INFO_KHR = 1000008000,
        VK_STRUCTURE_TYPE_WIN32_SURFACE_CREATE_INFO_KHR = 1000009000,
        VK_STRUCTURE_TYPE_DEBUG_REPORT_CALLBACK_CREATE_INFO_EXT = 1000011000,
        VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_RASTERIZATION_ORDER_AMD = 1000018000,
        VK_STRUCTURE_TYPE_DEBUG_MARKER_OBJECT_NAME_INFO_EXT = 1000022000,
        VK_STRUCTURE_TYPE_DEBUG_MARKER_OBJECT_TAG_INFO_EXT = 1000022001,
        VK_STRUCTURE_TYPE_DEBUG_MARKER_MARKER_INFO_EXT = 1000022002,
        VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_IMAGE_CREATE_INFO_NV = 1000026000,
        VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_BUFFER_CREATE_INFO_NV = 1000026001,
        VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_MEMORY_ALLOCATE_INFO_NV = 1000026002,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TRANSFORM_FEEDBACK_FEATURES_EXT = 1000028000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TRANSFORM_FEEDBACK_PROPERTIES_EXT = 1000028001,
        VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_STREAM_CREATE_INFO_EXT = 1000028002,
        VK_STRUCTURE_TYPE_IMAGE_VIEW_HANDLE_INFO_NVX = 1000030000,
        VK_STRUCTURE_TYPE_TEXTURE_LOD_GATHER_FORMAT_PROPERTIES_AMD = 1000041000,
        VK_STRUCTURE_TYPE_STREAM_DESCRIPTOR_SURFACE_CREATE_INFO_GGP = 1000049000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_CORNER_SAMPLED_IMAGE_FEATURES_NV = 1000050000,
        VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_IMAGE_CREATE_INFO_NV = 1000056000,
        VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO_NV = 1000056001,
        VK_STRUCTURE_TYPE_IMPORT_MEMORY_WIN32_HANDLE_INFO_NV = 1000057000,
        VK_STRUCTURE_TYPE_EXPORT_MEMORY_WIN32_HANDLE_INFO_NV = 1000057001,
        VK_STRUCTURE_TYPE_WIN32_KEYED_MUTEX_ACQUIRE_RELEASE_INFO_NV = 1000058000,
        VK_STRUCTURE_TYPE_VALIDATION_FLAGS_EXT = 1000061000,
        VK_STRUCTURE_TYPE_VI_SURFACE_CREATE_INFO_NN = 1000062000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TEXTURE_COMPRESSION_ASTC_HDR_FEATURES_EXT = 1000066000,
        VK_STRUCTURE_TYPE_IMAGE_VIEW_ASTC_DECODE_MODE_EXT = 1000067000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_ASTC_DECODE_FEATURES_EXT = 1000067001,
        VK_STRUCTURE_TYPE_IMPORT_MEMORY_WIN32_HANDLE_INFO_KHR = 1000073000,
        VK_STRUCTURE_TYPE_EXPORT_MEMORY_WIN32_HANDLE_INFO_KHR = 1000073001,
        VK_STRUCTURE_TYPE_MEMORY_WIN32_HANDLE_PROPERTIES_KHR = 1000073002,
        VK_STRUCTURE_TYPE_MEMORY_GET_WIN32_HANDLE_INFO_KHR = 1000073003,
        VK_STRUCTURE_TYPE_IMPORT_MEMORY_FD_INFO_KHR = 1000074000,
        VK_STRUCTURE_TYPE_MEMORY_FD_PROPERTIES_KHR = 1000074001,
        VK_STRUCTURE_TYPE_MEMORY_GET_FD_INFO_KHR = 1000074002,
        VK_STRUCTURE_TYPE_WIN32_KEYED_MUTEX_ACQUIRE_RELEASE_INFO_KHR = 1000075000,
        VK_STRUCTURE_TYPE_IMPORT_SEMAPHORE_WIN32_HANDLE_INFO_KHR = 1000078000,
        VK_STRUCTURE_TYPE_EXPORT_SEMAPHORE_WIN32_HANDLE_INFO_KHR = 1000078001,
        VK_STRUCTURE_TYPE_D3D12_FENCE_SUBMIT_INFO_KHR = 1000078002,
        VK_STRUCTURE_TYPE_SEMAPHORE_GET_WIN32_HANDLE_INFO_KHR = 1000078003,
        VK_STRUCTURE_TYPE_IMPORT_SEMAPHORE_FD_INFO_KHR = 1000079000,
        VK_STRUCTURE_TYPE_SEMAPHORE_GET_FD_INFO_KHR = 1000079001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PUSH_DESCRIPTOR_PROPERTIES_KHR = 1000080000,
        VK_STRUCTURE_TYPE_COMMAND_BUFFER_INHERITANCE_CONDITIONAL_RENDERING_INFO_EXT = 1000081000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_CONDITIONAL_RENDERING_FEATURES_EXT = 1000081001,
        VK_STRUCTURE_TYPE_CONDITIONAL_RENDERING_BEGIN_INFO_EXT = 1000081002,
        VK_STRUCTURE_TYPE_PRESENT_REGIONS_KHR = 1000084000,
        VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_W_SCALING_STATE_CREATE_INFO_NV = 1000087000,
        VK_STRUCTURE_TYPE_SURFACE_CAPABILITIES_2_EXT = 1000090000,
        VK_STRUCTURE_TYPE_DISPLAY_POWER_INFO_EXT = 1000091000,
        VK_STRUCTURE_TYPE_DEVICE_EVENT_INFO_EXT = 1000091001,
        VK_STRUCTURE_TYPE_DISPLAY_EVENT_INFO_EXT = 1000091002,
        VK_STRUCTURE_TYPE_SWAPCHAIN_COUNTER_CREATE_INFO_EXT = 1000091003,
        VK_STRUCTURE_TYPE_PRESENT_TIMES_INFO_GOOGLE = 1000092000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_PER_VIEW_ATTRIBUTES_PROPERTIES_NVX = 1000097000,
        VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_SWIZZLE_STATE_CREATE_INFO_NV = 1000098000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DISCARD_RECTANGLE_PROPERTIES_EXT = 1000099000,
        VK_STRUCTURE_TYPE_PIPELINE_DISCARD_RECTANGLE_STATE_CREATE_INFO_EXT = 1000099001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_CONSERVATIVE_RASTERIZATION_PROPERTIES_EXT = 1000101000,
        VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_CONSERVATIVE_STATE_CREATE_INFO_EXT = 1000101001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DEPTH_CLIP_ENABLE_FEATURES_EXT = 1000102000,
        VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_DEPTH_CLIP_STATE_CREATE_INFO_EXT = 1000102001,
        VK_STRUCTURE_TYPE_HDR_METADATA_EXT = 1000105000,
        VK_STRUCTURE_TYPE_SHARED_PRESENT_SURFACE_CAPABILITIES_KHR = 1000111000,
        VK_STRUCTURE_TYPE_IMPORT_FENCE_WIN32_HANDLE_INFO_KHR = 1000114000,
        VK_STRUCTURE_TYPE_EXPORT_FENCE_WIN32_HANDLE_INFO_KHR = 1000114001,
        VK_STRUCTURE_TYPE_FENCE_GET_WIN32_HANDLE_INFO_KHR = 1000114002,
        VK_STRUCTURE_TYPE_IMPORT_FENCE_FD_INFO_KHR = 1000115000,
        VK_STRUCTURE_TYPE_FENCE_GET_FD_INFO_KHR = 1000115001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PERFORMANCE_QUERY_FEATURES_KHR = 1000116000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PERFORMANCE_QUERY_PROPERTIES_KHR = 1000116001,
        VK_STRUCTURE_TYPE_QUERY_POOL_PERFORMANCE_CREATE_INFO_KHR = 1000116002,
        VK_STRUCTURE_TYPE_PERFORMANCE_QUERY_SUBMIT_INFO_KHR = 1000116003,
        VK_STRUCTURE_TYPE_ACQUIRE_PROFILING_LOCK_INFO_KHR = 1000116004,
        VK_STRUCTURE_TYPE_PERFORMANCE_COUNTER_KHR = 1000116005,
        VK_STRUCTURE_TYPE_PERFORMANCE_COUNTER_DESCRIPTION_KHR = 1000116006,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SURFACE_INFO_2_KHR = 1000119000,
        VK_STRUCTURE_TYPE_SURFACE_CAPABILITIES_2_KHR = 1000119001,
        VK_STRUCTURE_TYPE_SURFACE_FORMAT_2_KHR = 1000119002,
        VK_STRUCTURE_TYPE_DISPLAY_PROPERTIES_2_KHR = 1000121000,
        VK_STRUCTURE_TYPE_DISPLAY_PLANE_PROPERTIES_2_KHR = 1000121001,
        VK_STRUCTURE_TYPE_DISPLAY_MODE_PROPERTIES_2_KHR = 1000121002,
        VK_STRUCTURE_TYPE_DISPLAY_PLANE_INFO_2_KHR = 1000121003,
        VK_STRUCTURE_TYPE_DISPLAY_PLANE_CAPABILITIES_2_KHR = 1000121004,
        VK_STRUCTURE_TYPE_IOS_SURFACE_CREATE_INFO_MVK = 1000122000,
        VK_STRUCTURE_TYPE_MACOS_SURFACE_CREATE_INFO_MVK = 1000123000,
        VK_STRUCTURE_TYPE_DEBUG_UTILS_OBJECT_NAME_INFO_EXT = 1000128000,
        VK_STRUCTURE_TYPE_DEBUG_UTILS_OBJECT_TAG_INFO_EXT = 1000128001,
        VK_STRUCTURE_TYPE_DEBUG_UTILS_LABEL_EXT = 1000128002,
        VK_STRUCTURE_TYPE_DEBUG_UTILS_MESSENGER_CALLBACK_DATA_EXT = 1000128003,
        VK_STRUCTURE_TYPE_DEBUG_UTILS_MESSENGER_CREATE_INFO_EXT = 1000128004,
        VK_STRUCTURE_TYPE_ANDROID_HARDWARE_BUFFER_USAGE_ANDROID = 1000129000,
        VK_STRUCTURE_TYPE_ANDROID_HARDWARE_BUFFER_PROPERTIES_ANDROID = 1000129001,
        VK_STRUCTURE_TYPE_ANDROID_HARDWARE_BUFFER_FORMAT_PROPERTIES_ANDROID = 1000129002,
        VK_STRUCTURE_TYPE_IMPORT_ANDROID_HARDWARE_BUFFER_INFO_ANDROID = 1000129003,
        VK_STRUCTURE_TYPE_MEMORY_GET_ANDROID_HARDWARE_BUFFER_INFO_ANDROID = 1000129004,
        VK_STRUCTURE_TYPE_EXTERNAL_FORMAT_ANDROID = 1000129005,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_INLINE_UNIFORM_BLOCK_FEATURES_EXT = 1000138000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_INLINE_UNIFORM_BLOCK_PROPERTIES_EXT = 1000138001,
        VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET_INLINE_UNIFORM_BLOCK_EXT = 1000138002,
        VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_INLINE_UNIFORM_BLOCK_CREATE_INFO_EXT = 1000138003,
        VK_STRUCTURE_TYPE_SAMPLE_LOCATIONS_INFO_EXT = 1000143000,
        VK_STRUCTURE_TYPE_RENDER_PASS_SAMPLE_LOCATIONS_BEGIN_INFO_EXT = 1000143001,
        VK_STRUCTURE_TYPE_PIPELINE_SAMPLE_LOCATIONS_STATE_CREATE_INFO_EXT = 1000143002,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SAMPLE_LOCATIONS_PROPERTIES_EXT = 1000143003,
        VK_STRUCTURE_TYPE_MULTISAMPLE_PROPERTIES_EXT = 1000143004,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_BLEND_OPERATION_ADVANCED_FEATURES_EXT = 1000148000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_BLEND_OPERATION_ADVANCED_PROPERTIES_EXT = 1000148001,
        VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_ADVANCED_STATE_CREATE_INFO_EXT = 1000148002,
        VK_STRUCTURE_TYPE_PIPELINE_COVERAGE_TO_COLOR_STATE_CREATE_INFO_NV = 1000149000,
        VK_STRUCTURE_TYPE_BIND_ACCELERATION_STRUCTURE_MEMORY_INFO_KHR = 1000165006,
        VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET_ACCELERATION_STRUCTURE_KHR = 1000165007,
        VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_BUILD_GEOMETRY_INFO_KHR = 1000150000,
        VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_CREATE_GEOMETRY_TYPE_INFO_KHR = 1000150001,
        VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_DEVICE_ADDRESS_INFO_KHR = 1000150002,
        VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_GEOMETRY_AABBS_DATA_KHR = 1000150003,
        VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_GEOMETRY_INSTANCES_DATA_KHR = 1000150004,
        VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_GEOMETRY_TRIANGLES_DATA_KHR = 1000150005,
        VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_GEOMETRY_KHR = 1000150006,
        VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_INFO_KHR = 1000150007,
        VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_INFO_KHR = 1000150008,
        VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_VERSION_KHR = 1000150009,
        VK_STRUCTURE_TYPE_COPY_ACCELERATION_STRUCTURE_INFO_KHR = 1000150010,
        VK_STRUCTURE_TYPE_COPY_ACCELERATION_STRUCTURE_TO_MEMORY_INFO_KHR = 1000150011,
        VK_STRUCTURE_TYPE_COPY_MEMORY_TO_ACCELERATION_STRUCTURE_INFO_KHR = 1000150012,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_RAY_TRACING_FEATURES_KHR = 1000150013,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_RAY_TRACING_PROPERTIES_KHR = 1000150014,
        VK_STRUCTURE_TYPE_RAY_TRACING_PIPELINE_CREATE_INFO_KHR = 1000150015,
        VK_STRUCTURE_TYPE_RAY_TRACING_SHADER_GROUP_CREATE_INFO_KHR = 1000150016,
        VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_CREATE_INFO_KHR = 1000150017,
        VK_STRUCTURE_TYPE_RAY_TRACING_PIPELINE_INTERFACE_CREATE_INFO_KHR = 1000150018,
        VK_STRUCTURE_TYPE_PIPELINE_COVERAGE_MODULATION_STATE_CREATE_INFO_NV = 1000152000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_SM_BUILTINS_FEATURES_NV = 1000154000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_SM_BUILTINS_PROPERTIES_NV = 1000154001,
        VK_STRUCTURE_TYPE_DRM_FORMAT_MODIFIER_PROPERTIES_LIST_EXT = 1000158000,
        VK_STRUCTURE_TYPE_DRM_FORMAT_MODIFIER_PROPERTIES_EXT = 1000158001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGE_DRM_FORMAT_MODIFIER_INFO_EXT = 1000158002,
        VK_STRUCTURE_TYPE_IMAGE_DRM_FORMAT_MODIFIER_LIST_CREATE_INFO_EXT = 1000158003,
        VK_STRUCTURE_TYPE_IMAGE_DRM_FORMAT_MODIFIER_EXPLICIT_CREATE_INFO_EXT = 1000158004,
        VK_STRUCTURE_TYPE_IMAGE_DRM_FORMAT_MODIFIER_PROPERTIES_EXT = 1000158005,
        VK_STRUCTURE_TYPE_VALIDATION_CACHE_CREATE_INFO_EXT = 1000160000,
        VK_STRUCTURE_TYPE_SHADER_MODULE_VALIDATION_CACHE_CREATE_INFO_EXT = 1000160001,
        VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_SHADING_RATE_IMAGE_STATE_CREATE_INFO_NV = 1000164000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADING_RATE_IMAGE_FEATURES_NV = 1000164001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADING_RATE_IMAGE_PROPERTIES_NV = 1000164002,
        VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_COARSE_SAMPLE_ORDER_STATE_CREATE_INFO_NV = 1000164005,
        VK_STRUCTURE_TYPE_RAY_TRACING_PIPELINE_CREATE_INFO_NV = 1000165000,
        VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_CREATE_INFO_NV = 1000165001,
        VK_STRUCTURE_TYPE_GEOMETRY_NV = 1000165003,
        VK_STRUCTURE_TYPE_GEOMETRY_TRIANGLES_NV = 1000165004,
        VK_STRUCTURE_TYPE_GEOMETRY_AABB_NV = 1000165005,
        VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_INFO_NV = 1000165008,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_RAY_TRACING_PROPERTIES_NV = 1000165009,
        VK_STRUCTURE_TYPE_RAY_TRACING_SHADER_GROUP_CREATE_INFO_NV = 1000165011,
        VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_INFO_NV = 1000165012,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_REPRESENTATIVE_FRAGMENT_TEST_FEATURES_NV = 1000166000,
        VK_STRUCTURE_TYPE_PIPELINE_REPRESENTATIVE_FRAGMENT_TEST_STATE_CREATE_INFO_NV = 1000166001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGE_VIEW_IMAGE_FORMAT_INFO_EXT = 1000170000,
        VK_STRUCTURE_TYPE_FILTER_CUBIC_IMAGE_VIEW_IMAGE_FORMAT_PROPERTIES_EXT = 1000170001,
        VK_STRUCTURE_TYPE_DEVICE_QUEUE_GLOBAL_PRIORITY_CREATE_INFO_EXT = 1000174000,
        VK_STRUCTURE_TYPE_IMPORT_MEMORY_HOST_POINTER_INFO_EXT = 1000178000,
        VK_STRUCTURE_TYPE_MEMORY_HOST_POINTER_PROPERTIES_EXT = 1000178001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_MEMORY_HOST_PROPERTIES_EXT = 1000178002,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_CLOCK_FEATURES_KHR = 1000181000,
        VK_STRUCTURE_TYPE_PIPELINE_COMPILER_CONTROL_CREATE_INFO_AMD = 1000183000,
        VK_STRUCTURE_TYPE_CALIBRATED_TIMESTAMP_INFO_EXT = 1000184000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_CORE_PROPERTIES_AMD = 1000185000,
        VK_STRUCTURE_TYPE_DEVICE_MEMORY_OVERALLOCATION_CREATE_INFO_AMD = 1000189000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VERTEX_ATTRIBUTE_DIVISOR_PROPERTIES_EXT = 1000190000,
        VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_DIVISOR_STATE_CREATE_INFO_EXT = 1000190001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VERTEX_ATTRIBUTE_DIVISOR_FEATURES_EXT = 1000190002,
        VK_STRUCTURE_TYPE_PRESENT_FRAME_TOKEN_GGP = 1000191000,
        VK_STRUCTURE_TYPE_PIPELINE_CREATION_FEEDBACK_CREATE_INFO_EXT = 1000192000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_COMPUTE_SHADER_DERIVATIVES_FEATURES_NV = 1000201000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MESH_SHADER_FEATURES_NV = 1000202000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MESH_SHADER_PROPERTIES_NV = 1000202001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FRAGMENT_SHADER_BARYCENTRIC_FEATURES_NV = 1000203000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_IMAGE_FOOTPRINT_FEATURES_NV = 1000204000,
        VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_EXCLUSIVE_SCISSOR_STATE_CREATE_INFO_NV = 1000205000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXCLUSIVE_SCISSOR_FEATURES_NV = 1000205002,
        VK_STRUCTURE_TYPE_CHECKPOINT_DATA_NV = 1000206000,
        VK_STRUCTURE_TYPE_QUEUE_FAMILY_CHECKPOINT_PROPERTIES_NV = 1000206001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_INTEGER_FUNCTIONS_2_FEATURES_INTEL = 1000209000,
        VK_STRUCTURE_TYPE_QUERY_POOL_CREATE_INFO_INTEL = 1000210000,
        VK_STRUCTURE_TYPE_INITIALIZE_PERFORMANCE_API_INFO_INTEL = 1000210001,
        VK_STRUCTURE_TYPE_PERFORMANCE_MARKER_INFO_INTEL = 1000210002,
        VK_STRUCTURE_TYPE_PERFORMANCE_STREAM_MARKER_INFO_INTEL = 1000210003,
        VK_STRUCTURE_TYPE_PERFORMANCE_OVERRIDE_INFO_INTEL = 1000210004,
        VK_STRUCTURE_TYPE_PERFORMANCE_CONFIGURATION_ACQUIRE_INFO_INTEL = 1000210005,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PCI_BUS_INFO_PROPERTIES_EXT = 1000212000,
        VK_STRUCTURE_TYPE_DISPLAY_NATIVE_HDR_SURFACE_CAPABILITIES_AMD = 1000213000,
        VK_STRUCTURE_TYPE_SWAPCHAIN_DISPLAY_NATIVE_HDR_CREATE_INFO_AMD = 1000213001,
        VK_STRUCTURE_TYPE_IMAGEPIPE_SURFACE_CREATE_INFO_FUCHSIA = 1000214000,
        VK_STRUCTURE_TYPE_METAL_SURFACE_CREATE_INFO_EXT = 1000217000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FRAGMENT_DENSITY_MAP_FEATURES_EXT = 1000218000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FRAGMENT_DENSITY_MAP_PROPERTIES_EXT = 1000218001,
        VK_STRUCTURE_TYPE_RENDER_PASS_FRAGMENT_DENSITY_MAP_CREATE_INFO_EXT = 1000218002,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SUBGROUP_SIZE_CONTROL_PROPERTIES_EXT = 1000225000,
        VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_REQUIRED_SUBGROUP_SIZE_CREATE_INFO_EXT = 1000225001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SUBGROUP_SIZE_CONTROL_FEATURES_EXT = 1000225002,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_CORE_PROPERTIES_2_AMD = 1000227000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_COHERENT_MEMORY_FEATURES_AMD = 1000229000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_BUDGET_PROPERTIES_EXT = 1000237000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_PRIORITY_FEATURES_EXT = 1000238000,
        VK_STRUCTURE_TYPE_MEMORY_PRIORITY_ALLOCATE_INFO_EXT = 1000238001,
        VK_STRUCTURE_TYPE_SURFACE_PROTECTED_CAPABILITIES_KHR = 1000239000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DEDICATED_ALLOCATION_IMAGE_ALIASING_FEATURES_NV = 1000240000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_BUFFER_DEVICE_ADDRESS_FEATURES_EXT = 1000244000,
        VK_STRUCTURE_TYPE_BUFFER_DEVICE_ADDRESS_CREATE_INFO_EXT = 1000244002,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TOOL_PROPERTIES_EXT = 1000245000,
        VK_STRUCTURE_TYPE_VALIDATION_FEATURES_EXT = 1000247000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_COOPERATIVE_MATRIX_FEATURES_NV = 1000249000,
        VK_STRUCTURE_TYPE_COOPERATIVE_MATRIX_PROPERTIES_NV = 1000249001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_COOPERATIVE_MATRIX_PROPERTIES_NV = 1000249002,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_COVERAGE_REDUCTION_MODE_FEATURES_NV = 1000250000,
        VK_STRUCTURE_TYPE_PIPELINE_COVERAGE_REDUCTION_STATE_CREATE_INFO_NV = 1000250001,
        VK_STRUCTURE_TYPE_FRAMEBUFFER_MIXED_SAMPLES_COMBINATION_NV = 1000250002,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FRAGMENT_SHADER_INTERLOCK_FEATURES_EXT = 1000251000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_YCBCR_IMAGE_ARRAYS_FEATURES_EXT = 1000252000,
        VK_STRUCTURE_TYPE_SURFACE_FULL_SCREEN_EXCLUSIVE_INFO_EXT = 1000255000,
        VK_STRUCTURE_TYPE_SURFACE_CAPABILITIES_FULL_SCREEN_EXCLUSIVE_EXT = 1000255002,
        VK_STRUCTURE_TYPE_SURFACE_FULL_SCREEN_EXCLUSIVE_WIN32_INFO_EXT = 1000255001,
        VK_STRUCTURE_TYPE_HEADLESS_SURFACE_CREATE_INFO_EXT = 1000256000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_LINE_RASTERIZATION_FEATURES_EXT = 1000259000,
        VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_LINE_STATE_CREATE_INFO_EXT = 1000259001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_LINE_RASTERIZATION_PROPERTIES_EXT = 1000259002,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_INDEX_TYPE_UINT8_FEATURES_EXT = 1000265000,
        VK_STRUCTURE_TYPE_DEFERRED_OPERATION_INFO_KHR = 1000268000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PIPELINE_EXECUTABLE_PROPERTIES_FEATURES_KHR = 1000269000,
        VK_STRUCTURE_TYPE_PIPELINE_INFO_KHR = 1000269001,
        VK_STRUCTURE_TYPE_PIPELINE_EXECUTABLE_PROPERTIES_KHR = 1000269002,
        VK_STRUCTURE_TYPE_PIPELINE_EXECUTABLE_INFO_KHR = 1000269003,
        VK_STRUCTURE_TYPE_PIPELINE_EXECUTABLE_STATISTIC_KHR = 1000269004,
        VK_STRUCTURE_TYPE_PIPELINE_EXECUTABLE_INTERNAL_REPRESENTATION_KHR = 1000269005,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_DEMOTE_TO_HELPER_INVOCATION_FEATURES_EXT = 1000276000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DEVICE_GENERATED_COMMANDS_PROPERTIES_NV = 1000277000,
        VK_STRUCTURE_TYPE_GRAPHICS_SHADER_GROUP_CREATE_INFO_NV = 1000277001,
        VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_SHADER_GROUPS_CREATE_INFO_NV = 1000277002,
        VK_STRUCTURE_TYPE_INDIRECT_COMMANDS_LAYOUT_TOKEN_NV = 1000277003,
        VK_STRUCTURE_TYPE_INDIRECT_COMMANDS_LAYOUT_CREATE_INFO_NV = 1000277004,
        VK_STRUCTURE_TYPE_GENERATED_COMMANDS_INFO_NV = 1000277005,
        VK_STRUCTURE_TYPE_GENERATED_COMMANDS_MEMORY_REQUIREMENTS_INFO_NV = 1000277006,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DEVICE_GENERATED_COMMANDS_FEATURES_NV = 1000277007,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TEXEL_BUFFER_ALIGNMENT_FEATURES_EXT = 1000281000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TEXEL_BUFFER_ALIGNMENT_PROPERTIES_EXT = 1000281001,
        VK_STRUCTURE_TYPE_COMMAND_BUFFER_INHERITANCE_RENDER_PASS_TRANSFORM_INFO_QCOM = 1000282000,
        VK_STRUCTURE_TYPE_RENDER_PASS_TRANSFORM_BEGIN_INFO_QCOM = 1000282001,
        VK_STRUCTURE_TYPE_PIPELINE_LIBRARY_CREATE_INFO_KHR = 1000290000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PIPELINE_CREATION_CACHE_CONTROL_FEATURES_EXT = 1000297000,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DIAGNOSTICS_CONFIG_FEATURES_NV = 1000300000,
        VK_STRUCTURE_TYPE_DEVICE_DIAGNOSTICS_CONFIG_CREATE_INFO_NV = 1000300001,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VARIABLE_POINTER_FEATURES = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VARIABLE_POINTERS_FEATURES,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_DRAW_PARAMETER_FEATURES = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_DRAW_PARAMETERS_FEATURES,
        VK_STRUCTURE_TYPE_DEBUG_REPORT_CREATE_INFO_EXT = VK_STRUCTURE_TYPE_DEBUG_REPORT_CALLBACK_CREATE_INFO_EXT,
        VK_STRUCTURE_TYPE_RENDER_PASS_MULTIVIEW_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_RENDER_PASS_MULTIVIEW_CREATE_INFO,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_FEATURES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_FEATURES,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_PROPERTIES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_PROPERTIES,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FEATURES_2_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FEATURES_2,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROPERTIES_2_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROPERTIES_2,
        VK_STRUCTURE_TYPE_FORMAT_PROPERTIES_2_KHR = VK_STRUCTURE_TYPE_FORMAT_PROPERTIES_2,
        VK_STRUCTURE_TYPE_IMAGE_FORMAT_PROPERTIES_2_KHR = VK_STRUCTURE_TYPE_IMAGE_FORMAT_PROPERTIES_2,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGE_FORMAT_INFO_2_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGE_FORMAT_INFO_2,
        VK_STRUCTURE_TYPE_QUEUE_FAMILY_PROPERTIES_2_KHR = VK_STRUCTURE_TYPE_QUEUE_FAMILY_PROPERTIES_2,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_PROPERTIES_2_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_PROPERTIES_2,
        VK_STRUCTURE_TYPE_SPARSE_IMAGE_FORMAT_PROPERTIES_2_KHR = VK_STRUCTURE_TYPE_SPARSE_IMAGE_FORMAT_PROPERTIES_2,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SPARSE_IMAGE_FORMAT_INFO_2_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SPARSE_IMAGE_FORMAT_INFO_2,
        VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_FLAGS_INFO_KHR = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_FLAGS_INFO,
        VK_STRUCTURE_TYPE_DEVICE_GROUP_RENDER_PASS_BEGIN_INFO_KHR = VK_STRUCTURE_TYPE_DEVICE_GROUP_RENDER_PASS_BEGIN_INFO,
        VK_STRUCTURE_TYPE_DEVICE_GROUP_COMMAND_BUFFER_BEGIN_INFO_KHR = VK_STRUCTURE_TYPE_DEVICE_GROUP_COMMAND_BUFFER_BEGIN_INFO,
        VK_STRUCTURE_TYPE_DEVICE_GROUP_SUBMIT_INFO_KHR = VK_STRUCTURE_TYPE_DEVICE_GROUP_SUBMIT_INFO,
        VK_STRUCTURE_TYPE_DEVICE_GROUP_BIND_SPARSE_INFO_KHR = VK_STRUCTURE_TYPE_DEVICE_GROUP_BIND_SPARSE_INFO,
        VK_STRUCTURE_TYPE_BIND_BUFFER_MEMORY_DEVICE_GROUP_INFO_KHR = VK_STRUCTURE_TYPE_BIND_BUFFER_MEMORY_DEVICE_GROUP_INFO,
        VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_DEVICE_GROUP_INFO_KHR = VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_DEVICE_GROUP_INFO,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_GROUP_PROPERTIES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_GROUP_PROPERTIES,
        VK_STRUCTURE_TYPE_DEVICE_GROUP_DEVICE_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_DEVICE_GROUP_DEVICE_CREATE_INFO,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_IMAGE_FORMAT_INFO_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_IMAGE_FORMAT_INFO,
        VK_STRUCTURE_TYPE_EXTERNAL_IMAGE_FORMAT_PROPERTIES_KHR = VK_STRUCTURE_TYPE_EXTERNAL_IMAGE_FORMAT_PROPERTIES,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_BUFFER_INFO_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_BUFFER_INFO,
        VK_STRUCTURE_TYPE_EXTERNAL_BUFFER_PROPERTIES_KHR = VK_STRUCTURE_TYPE_EXTERNAL_BUFFER_PROPERTIES,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_ID_PROPERTIES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_ID_PROPERTIES,
        VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_BUFFER_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_BUFFER_CREATE_INFO,
        VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_IMAGE_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_IMAGE_CREATE_INFO,
        VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO_KHR = VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_SEMAPHORE_INFO_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_SEMAPHORE_INFO,
        VK_STRUCTURE_TYPE_EXTERNAL_SEMAPHORE_PROPERTIES_KHR = VK_STRUCTURE_TYPE_EXTERNAL_SEMAPHORE_PROPERTIES,
        VK_STRUCTURE_TYPE_EXPORT_SEMAPHORE_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_EXPORT_SEMAPHORE_CREATE_INFO,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_FLOAT16_INT8_FEATURES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_FLOAT16_INT8_FEATURES,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FLOAT16_INT8_FEATURES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_FLOAT16_INT8_FEATURES,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_16BIT_STORAGE_FEATURES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_16BIT_STORAGE_FEATURES,
        VK_STRUCTURE_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_CREATE_INFO,
        VK_STRUCTURE_TYPE_SURFACE_CAPABILITIES2_EXT = VK_STRUCTURE_TYPE_SURFACE_CAPABILITIES_2_EXT,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGELESS_FRAMEBUFFER_FEATURES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGELESS_FRAMEBUFFER_FEATURES,
        VK_STRUCTURE_TYPE_FRAMEBUFFER_ATTACHMENTS_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_FRAMEBUFFER_ATTACHMENTS_CREATE_INFO,
        VK_STRUCTURE_TYPE_FRAMEBUFFER_ATTACHMENT_IMAGE_INFO_KHR = VK_STRUCTURE_TYPE_FRAMEBUFFER_ATTACHMENT_IMAGE_INFO,
        VK_STRUCTURE_TYPE_RENDER_PASS_ATTACHMENT_BEGIN_INFO_KHR = VK_STRUCTURE_TYPE_RENDER_PASS_ATTACHMENT_BEGIN_INFO,
        VK_STRUCTURE_TYPE_ATTACHMENT_DESCRIPTION_2_KHR = VK_STRUCTURE_TYPE_ATTACHMENT_DESCRIPTION_2,
        VK_STRUCTURE_TYPE_ATTACHMENT_REFERENCE_2_KHR = VK_STRUCTURE_TYPE_ATTACHMENT_REFERENCE_2,
        VK_STRUCTURE_TYPE_SUBPASS_DESCRIPTION_2_KHR = VK_STRUCTURE_TYPE_SUBPASS_DESCRIPTION_2,
        VK_STRUCTURE_TYPE_SUBPASS_DEPENDENCY_2_KHR = VK_STRUCTURE_TYPE_SUBPASS_DEPENDENCY_2,
        VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO_2_KHR = VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO_2,
        VK_STRUCTURE_TYPE_SUBPASS_BEGIN_INFO_KHR = VK_STRUCTURE_TYPE_SUBPASS_BEGIN_INFO,
        VK_STRUCTURE_TYPE_SUBPASS_END_INFO_KHR = VK_STRUCTURE_TYPE_SUBPASS_END_INFO,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_FENCE_INFO_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_FENCE_INFO,
        VK_STRUCTURE_TYPE_EXTERNAL_FENCE_PROPERTIES_KHR = VK_STRUCTURE_TYPE_EXTERNAL_FENCE_PROPERTIES,
        VK_STRUCTURE_TYPE_EXPORT_FENCE_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_EXPORT_FENCE_CREATE_INFO,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_POINT_CLIPPING_PROPERTIES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_POINT_CLIPPING_PROPERTIES,
        VK_STRUCTURE_TYPE_RENDER_PASS_INPUT_ATTACHMENT_ASPECT_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_RENDER_PASS_INPUT_ATTACHMENT_ASPECT_CREATE_INFO,
        VK_STRUCTURE_TYPE_IMAGE_VIEW_USAGE_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_IMAGE_VIEW_USAGE_CREATE_INFO,
        VK_STRUCTURE_TYPE_PIPELINE_TESSELLATION_DOMAIN_ORIGIN_STATE_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_PIPELINE_TESSELLATION_DOMAIN_ORIGIN_STATE_CREATE_INFO,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VARIABLE_POINTER_FEATURES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VARIABLE_POINTER_FEATURES,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VARIABLE_POINTERS_FEATURES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VARIABLE_POINTER_FEATURES,
        VK_STRUCTURE_TYPE_MEMORY_DEDICATED_REQUIREMENTS_KHR = VK_STRUCTURE_TYPE_MEMORY_DEDICATED_REQUIREMENTS,
        VK_STRUCTURE_TYPE_MEMORY_DEDICATED_ALLOCATE_INFO_KHR = VK_STRUCTURE_TYPE_MEMORY_DEDICATED_ALLOCATE_INFO,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SAMPLER_FILTER_MINMAX_PROPERTIES_EXT = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SAMPLER_FILTER_MINMAX_PROPERTIES,
        VK_STRUCTURE_TYPE_SAMPLER_REDUCTION_MODE_CREATE_INFO_EXT = VK_STRUCTURE_TYPE_SAMPLER_REDUCTION_MODE_CREATE_INFO,
        VK_STRUCTURE_TYPE_BUFFER_MEMORY_REQUIREMENTS_INFO_2_KHR = VK_STRUCTURE_TYPE_BUFFER_MEMORY_REQUIREMENTS_INFO_2,
        VK_STRUCTURE_TYPE_IMAGE_MEMORY_REQUIREMENTS_INFO_2_KHR = VK_STRUCTURE_TYPE_IMAGE_MEMORY_REQUIREMENTS_INFO_2,
        VK_STRUCTURE_TYPE_IMAGE_SPARSE_MEMORY_REQUIREMENTS_INFO_2_KHR = VK_STRUCTURE_TYPE_IMAGE_SPARSE_MEMORY_REQUIREMENTS_INFO_2,
        VK_STRUCTURE_TYPE_MEMORY_REQUIREMENTS_2_KHR = VK_STRUCTURE_TYPE_MEMORY_REQUIREMENTS_2,
        VK_STRUCTURE_TYPE_SPARSE_IMAGE_MEMORY_REQUIREMENTS_2_KHR = VK_STRUCTURE_TYPE_SPARSE_IMAGE_MEMORY_REQUIREMENTS_2,
        VK_STRUCTURE_TYPE_IMAGE_FORMAT_LIST_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_IMAGE_FORMAT_LIST_CREATE_INFO,
        VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_CREATE_INFO,
        VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_INFO_KHR = VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_INFO,
        VK_STRUCTURE_TYPE_BIND_IMAGE_PLANE_MEMORY_INFO_KHR = VK_STRUCTURE_TYPE_BIND_IMAGE_PLANE_MEMORY_INFO,
        VK_STRUCTURE_TYPE_IMAGE_PLANE_MEMORY_REQUIREMENTS_INFO_KHR = VK_STRUCTURE_TYPE_IMAGE_PLANE_MEMORY_REQUIREMENTS_INFO,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SAMPLER_YCBCR_CONVERSION_FEATURES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SAMPLER_YCBCR_CONVERSION_FEATURES,
        VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_IMAGE_FORMAT_PROPERTIES_KHR = VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_IMAGE_FORMAT_PROPERTIES,
        VK_STRUCTURE_TYPE_BIND_BUFFER_MEMORY_INFO_KHR = VK_STRUCTURE_TYPE_BIND_BUFFER_MEMORY_INFO,
        VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_INFO_KHR = VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_INFO,
        VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_BINDING_FLAGS_CREATE_INFO_EXT = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_BINDING_FLAGS_CREATE_INFO,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_FEATURES_EXT = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_FEATURES,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_PROPERTIES_EXT = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_PROPERTIES,
        VK_STRUCTURE_TYPE_DESCRIPTOR_SET_VARIABLE_DESCRIPTOR_COUNT_ALLOCATE_INFO_EXT = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_VARIABLE_DESCRIPTOR_COUNT_ALLOCATE_INFO,
        VK_STRUCTURE_TYPE_DESCRIPTOR_SET_VARIABLE_DESCRIPTOR_COUNT_LAYOUT_SUPPORT_EXT = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_VARIABLE_DESCRIPTOR_COUNT_LAYOUT_SUPPORT,
        VK_STRUCTURE_TYPE_BIND_ACCELERATION_STRUCTURE_MEMORY_INFO_NV = VK_STRUCTURE_TYPE_BIND_ACCELERATION_STRUCTURE_MEMORY_INFO_KHR,
        VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET_ACCELERATION_STRUCTURE_NV = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET_ACCELERATION_STRUCTURE_KHR,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MAINTENANCE_3_PROPERTIES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MAINTENANCE_3_PROPERTIES,
        VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_SUPPORT_KHR = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_SUPPORT,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_SUBGROUP_EXTENDED_TYPES_FEATURES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_SUBGROUP_EXTENDED_TYPES_FEATURES,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_8BIT_STORAGE_FEATURES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_8BIT_STORAGE_FEATURES,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_ATOMIC_INT64_FEATURES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_ATOMIC_INT64_FEATURES,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DRIVER_PROPERTIES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DRIVER_PROPERTIES,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FLOAT_CONTROLS_PROPERTIES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FLOAT_CONTROLS_PROPERTIES,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DEPTH_STENCIL_RESOLVE_PROPERTIES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DEPTH_STENCIL_RESOLVE_PROPERTIES,
        VK_STRUCTURE_TYPE_SUBPASS_DESCRIPTION_DEPTH_STENCIL_RESOLVE_KHR = VK_STRUCTURE_TYPE_SUBPASS_DESCRIPTION_DEPTH_STENCIL_RESOLVE,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TIMELINE_SEMAPHORE_FEATURES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TIMELINE_SEMAPHORE_FEATURES,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TIMELINE_SEMAPHORE_PROPERTIES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TIMELINE_SEMAPHORE_PROPERTIES,
        VK_STRUCTURE_TYPE_SEMAPHORE_TYPE_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_SEMAPHORE_TYPE_CREATE_INFO,
        VK_STRUCTURE_TYPE_TIMELINE_SEMAPHORE_SUBMIT_INFO_KHR = VK_STRUCTURE_TYPE_TIMELINE_SEMAPHORE_SUBMIT_INFO,
        VK_STRUCTURE_TYPE_SEMAPHORE_WAIT_INFO_KHR = VK_STRUCTURE_TYPE_SEMAPHORE_WAIT_INFO,
        VK_STRUCTURE_TYPE_SEMAPHORE_SIGNAL_INFO_KHR = VK_STRUCTURE_TYPE_SEMAPHORE_SIGNAL_INFO,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VULKAN_MEMORY_MODEL_FEATURES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VULKAN_MEMORY_MODEL_FEATURES,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SCALAR_BLOCK_LAYOUT_FEATURES_EXT = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SCALAR_BLOCK_LAYOUT_FEATURES,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SEPARATE_DEPTH_STENCIL_LAYOUTS_FEATURES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SEPARATE_DEPTH_STENCIL_LAYOUTS_FEATURES,
        VK_STRUCTURE_TYPE_ATTACHMENT_REFERENCE_STENCIL_LAYOUT_KHR = VK_STRUCTURE_TYPE_ATTACHMENT_REFERENCE_STENCIL_LAYOUT,
        VK_STRUCTURE_TYPE_ATTACHMENT_DESCRIPTION_STENCIL_LAYOUT_KHR = VK_STRUCTURE_TYPE_ATTACHMENT_DESCRIPTION_STENCIL_LAYOUT,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_BUFFER_ADDRESS_FEATURES_EXT = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_BUFFER_DEVICE_ADDRESS_FEATURES_EXT,
        VK_STRUCTURE_TYPE_BUFFER_DEVICE_ADDRESS_INFO_EXT = VK_STRUCTURE_TYPE_BUFFER_DEVICE_ADDRESS_INFO,
        VK_STRUCTURE_TYPE_IMAGE_STENCIL_USAGE_CREATE_INFO_EXT = VK_STRUCTURE_TYPE_IMAGE_STENCIL_USAGE_CREATE_INFO,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_UNIFORM_BUFFER_STANDARD_LAYOUT_FEATURES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_UNIFORM_BUFFER_STANDARD_LAYOUT_FEATURES,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_BUFFER_DEVICE_ADDRESS_FEATURES_KHR = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_BUFFER_DEVICE_ADDRESS_FEATURES,
        VK_STRUCTURE_TYPE_BUFFER_DEVICE_ADDRESS_INFO_KHR = VK_STRUCTURE_TYPE_BUFFER_DEVICE_ADDRESS_INFO,
        VK_STRUCTURE_TYPE_BUFFER_OPAQUE_CAPTURE_ADDRESS_CREATE_INFO_KHR = VK_STRUCTURE_TYPE_BUFFER_OPAQUE_CAPTURE_ADDRESS_CREATE_INFO,
        VK_STRUCTURE_TYPE_MEMORY_OPAQUE_CAPTURE_ADDRESS_ALLOCATE_INFO_KHR = VK_STRUCTURE_TYPE_MEMORY_OPAQUE_CAPTURE_ADDRESS_ALLOCATE_INFO,
        VK_STRUCTURE_TYPE_DEVICE_MEMORY_OPAQUE_CAPTURE_ADDRESS_INFO_KHR = VK_STRUCTURE_TYPE_DEVICE_MEMORY_OPAQUE_CAPTURE_ADDRESS_INFO,
        VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_HOST_QUERY_RESET_FEATURES_EXT = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_HOST_QUERY_RESET_FEATURES,
        VK_STRUCTURE_TYPE_MAX_ENUM = 0x7FFFFFFF
    } VkStructureType;

Each value corresponds to a particular structure with a `sType` member with a matching name. As a general rule, the name of each VkStructureType value is obtained by taking the name of the structure, stripping the leading `Vk`, prefixing each capital letter with `_`, converting the entire resulting string to upper case, and prefixing it with `VK_STRUCTURE_TYPE_`. For example, structures of type `VkImageCreateInfo` correspond to a VkStructureType of `VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO`, and thus its `sType` member must equal that when it is passed to the API.

The values `VK_STRUCTURE_TYPE_LOADER_INSTANCE_CREATE_INFO` and `VK_STRUCTURE_TYPE_LOADER_DEVICE_CREATE_INFO` are reserved for internal use by the loader, and do not have corresponding Vulkan structures in this Specification.

##### Valid Usage for Structure Pointer Chains

Any parameter that is a structure containing a `void*` `pNext` member must have a value of `pNext` that is either `NULL`, or is a pointer to a valid structure defined by an extension, containing `sType` and `pNext` members as described in the Vulkan Documentation and Extensions document in the section “Extension Interactions”. The set of structures connected by `pNext` pointers is referred to as a `pNext` chain. If that extension is supported by the implementation, then it must be enabled.

Each type of valid structure must not appear more than once in a `pNext` chain, including any aliases.

Any component of the implementation (the loader, any enabled layers, and drivers) must skip over, without processing (other than reading the `sType` and `pNext` members) any structures in the chain with `sType` values not defined by extensions supported by that component.

Extension structures are not described in the base Vulkan Specification, but either in layered Specifications incorporating those extensions, or in separate vendor-provided documents.

As a convenience to implementations and layers needing to iterate through a structure pointer chain, the Vulkan API provides two base structures. These structures allow for some type safety, and can be used by Vulkan API functions that operate on generic inputs and outputs.

The `VkBaseInStructure` structure is defined as:

    typedef struct VkBaseInStructure {
        VkStructureType                    sType;
        const struct VkBaseInStructure*    pNext;
    } VkBaseInStructure;

- `sType` is the structure type of the structure being iterated through.

- `pNext` is `NULL` or a pointer to the next structure in a structure chain.

`VkBaseInStructure` can be used to facilitate iterating through a read-only structure pointer chain.

The `VkBaseOutStructure` structure is defined as:

    typedef struct VkBaseOutStructure {
        VkStructureType               sType;
        struct VkBaseOutStructure*    pNext;
    } VkBaseOutStructure;

- `sType` is the structure type of the structure being iterated through.

- `pNext` is `NULL` or a pointer to the next structure in a structure chain.

`VkBaseOutStructure` can be used to facilitate iterating through a structure pointer chain that returns data back to the application.

##### Valid Usage for Nested Structures

The above conditions also apply recursively to members of structures provided as input to a command, either as a direct argument to the command, or themselves a member of another structure.

Specifics on valid usage of each command are covered in their individual sections.

##### Valid Usage for Extensions

Instance-level functionality or behavior added by an instance extension to the API must not be used unless that extension is supported by the instance as determined by vkEnumerateInstanceExtensionProperties, and that extension is enabled in VkInstanceCreateInfo.

Physical-device-level functionality or behavior added by an instance extension to the API must not be used unless that extension is supported by the instance as determined by vkEnumerateInstanceExtensionProperties, and that extension is enabled in VkInstanceCreateInfo.

Physical-device-level functionality or behavior added by a device extension to the API must not be used unless the conditions described in Extending Physical Device Core Functionality are met.

Device functionality or behavior added by a device extension to the API must not be used unless that extension is supported by the device as determined by vkEnumerateDeviceExtensionProperties, and that extension is enabled in VkDeviceCreateInfo.

##### Valid Usage for Newer Core Versions

Instance-level functionality or behavior added by a new core version of the API must not be used unless it is supported by the instance as determined by vkEnumerateInstanceVersion and the specified version of VkApplicationInfo::`apiVersion`.

Physical-device-level functionality or behavior added by a new core version of the API must not be used unless it is supported by the physical device as determined by VkPhysicalDeviceProperties::`apiVersion` and the specified version of VkApplicationInfo::`apiVersion`.

Device-level functionality or behavior added by a new core version of the API must not be used unless it is supported by the device as determined by VkPhysicalDeviceProperties::`apiVersion` and the specified version of VkApplicationInfo::`apiVersion`.

#### 2.7.3. Return Codes

While the core Vulkan API is not designed to capture incorrect usage, some circumstances still require return codes. Commands in Vulkan return their status via return codes that are in one of two categories:

- Successful completion codes are returned when a command needs to communicate success or status information. All successful completion codes are non-negative values.

- Run time error codes are returned when a command needs to communicate a failure that could only be detected at run time. All run time error codes are negative values.

All return codes in Vulkan are reported via VkResult return values. The possible codes are:

    typedef enum VkResult {
        VK_SUCCESS = 0,
        VK_NOT_READY = 1,
        VK_TIMEOUT = 2,
        VK_EVENT_SET = 3,
        VK_EVENT_RESET = 4,
        VK_INCOMPLETE = 5,
        VK_ERROR_OUT_OF_HOST_MEMORY = -1,
        VK_ERROR_OUT_OF_DEVICE_MEMORY = -2,
        VK_ERROR_INITIALIZATION_FAILED = -3,
        VK_ERROR_DEVICE_LOST = -4,
        VK_ERROR_MEMORY_MAP_FAILED = -5,
        VK_ERROR_LAYER_NOT_PRESENT = -6,
        VK_ERROR_EXTENSION_NOT_PRESENT = -7,
        VK_ERROR_FEATURE_NOT_PRESENT = -8,
        VK_ERROR_INCOMPATIBLE_DRIVER = -9,
        VK_ERROR_TOO_MANY_OBJECTS = -10,
        VK_ERROR_FORMAT_NOT_SUPPORTED = -11,
        VK_ERROR_FRAGMENTED_POOL = -12,
        VK_ERROR_UNKNOWN = -13,
        VK_ERROR_OUT_OF_POOL_MEMORY = -1000069000,
        VK_ERROR_INVALID_EXTERNAL_HANDLE = -1000072003,
        VK_ERROR_FRAGMENTATION = -1000161000,
        VK_ERROR_INVALID_OPAQUE_CAPTURE_ADDRESS = -1000257000,
        VK_ERROR_SURFACE_LOST_KHR = -1000000000,
        VK_ERROR_NATIVE_WINDOW_IN_USE_KHR = -1000000001,
        VK_SUBOPTIMAL_KHR = 1000001003,
        VK_ERROR_OUT_OF_DATE_KHR = -1000001004,
        VK_ERROR_INCOMPATIBLE_DISPLAY_KHR = -1000003001,
        VK_ERROR_VALIDATION_FAILED_EXT = -1000011001,
        VK_ERROR_INVALID_SHADER_NV = -1000012000,
        VK_ERROR_INCOMPATIBLE_VERSION_KHR = -1000150000,
        VK_ERROR_INVALID_DRM_FORMAT_MODIFIER_PLANE_LAYOUT_EXT = -1000158000,
        VK_ERROR_NOT_PERMITTED_EXT = -1000174001,
        VK_ERROR_FULL_SCREEN_EXCLUSIVE_MODE_LOST_EXT = -1000255000,
        VK_THREAD_IDLE_KHR = 1000268000,
        VK_THREAD_DONE_KHR = 1000268001,
        VK_OPERATION_DEFERRED_KHR = 1000268002,
        VK_OPERATION_NOT_DEFERRED_KHR = 1000268003,
        VK_ERROR_PIPELINE_COMPILE_REQUIRED_EXT = 1000297000,
        VK_ERROR_OUT_OF_POOL_MEMORY_KHR = VK_ERROR_OUT_OF_POOL_MEMORY,
        VK_ERROR_INVALID_EXTERNAL_HANDLE_KHR = VK_ERROR_INVALID_EXTERNAL_HANDLE,
        VK_ERROR_FRAGMENTATION_EXT = VK_ERROR_FRAGMENTATION,
        VK_ERROR_INVALID_DEVICE_ADDRESS_EXT = VK_ERROR_INVALID_OPAQUE_CAPTURE_ADDRESS,
        VK_ERROR_INVALID_OPAQUE_CAPTURE_ADDRESS_KHR = VK_ERROR_INVALID_OPAQUE_CAPTURE_ADDRESS,
        VK_RESULT_MAX_ENUM = 0x7FFFFFFF
    } VkResult;

Success Codes

- `VK_SUCCESS` Command successfully completed

- `VK_NOT_READY` A fence or query has not yet completed

- `VK_TIMEOUT` A wait operation has not completed in the specified time

- `VK_EVENT_SET` An event is signaled

- `VK_EVENT_RESET` An event is unsignaled

- `VK_INCOMPLETE` A return array was too small for the result

- `VK_SUBOPTIMAL_KHR` A swapchain no longer matches the surface properties exactly, but can still be used to present to the surface successfully.

- `VK_THREAD_IDLE_KHR` A deferred operation is not complete but there is currently no work for this thread to do at the time of this call.

- `VK_THREAD_DONE_KHR` A deferred operation is not complete but there is no work remaining to assign to additional threads.

- `VK_OPERATION_DEFERRED_KHR` A deferred operation was requested and at least some of the work was deferred.

- `VK_OPERATION_NOT_DEFERRED_KHR` A deferred operation was requested and no operations were deferred.

Error codes

- `VK_ERROR_OUT_OF_HOST_MEMORY` A host memory allocation has failed.

- `VK_ERROR_OUT_OF_DEVICE_MEMORY` A device memory allocation has failed.

- `VK_ERROR_INITIALIZATION_FAILED` Initialization of an object could not be completed for implementation-specific reasons.

- `VK_ERROR_DEVICE_LOST` The logical or physical device has been lost. See Lost Device

- `VK_ERROR_MEMORY_MAP_FAILED` Mapping of a memory object has failed.

- `VK_ERROR_LAYER_NOT_PRESENT` A requested layer is not present or could not be loaded.

- `VK_ERROR_EXTENSION_NOT_PRESENT` A requested extension is not supported.

- `VK_ERROR_FEATURE_NOT_PRESENT` A requested feature is not supported.

- `VK_ERROR_INCOMPATIBLE_DRIVER` The requested version of Vulkan is not supported by the driver or is otherwise incompatible for implementation-specific reasons.

- `VK_ERROR_TOO_MANY_OBJECTS` Too many objects of the type have already been created.

- `VK_ERROR_FORMAT_NOT_SUPPORTED` A requested format is not supported on this device.

- `VK_ERROR_FRAGMENTED_POOL` A pool allocation has failed due to fragmentation of the pool’s memory. This must only be returned if no attempt to allocate host or device memory was made to accommodate the new allocation. This should be returned in preference to `VK_ERROR_OUT_OF_POOL_MEMORY`, but only if the implementation is certain that the pool allocation failure was due to fragmentation.

- `VK_ERROR_SURFACE_LOST_KHR` A surface is no longer available.

- `VK_ERROR_NATIVE_WINDOW_IN_USE_KHR` The requested window is already in use by Vulkan or another API in a manner which prevents it from being used again.

- `VK_ERROR_OUT_OF_DATE_KHR` A surface has changed in such a way that it is no longer compatible with the swapchain, and further presentation requests using the swapchain will fail. Applications must query the new surface properties and recreate their swapchain if they wish to continue presenting to the surface.

- `VK_ERROR_INCOMPATIBLE_DISPLAY_KHR` The display used by a swapchain does not use the same presentable image layout, or is incompatible in a way that prevents sharing an image.

- `VK_ERROR_INVALID_SHADER_NV` One or more shaders failed to compile or link. More details are reported back to the application via `VK_EXT_debug_report` if enabled.

- `VK_ERROR_OUT_OF_POOL_MEMORY` A pool memory allocation has failed. This must only be returned if no attempt to allocate host or device memory was made to accommodate the new allocation. If the failure was definitely due to fragmentation of the pool, `VK_ERROR_FRAGMENTED_POOL` should be returned instead.

- `VK_ERROR_INVALID_EXTERNAL_HANDLE` An external handle is not a valid handle of the specified type.

- `VK_ERROR_FRAGMENTATION` A descriptor pool creation has failed due to fragmentation.

- `VK_ERROR_INVALID_DEVICE_ADDRESS_EXT` A buffer creation failed because the requested address is not available.

- `VK_ERROR_INVALID_OPAQUE_CAPTURE_ADDRESS` A buffer creation or memory allocation failed because the requested address is not available. A shader group handle assignment failed because the requested shader group handle information is no longer valid.

- `VK_ERROR_FULL_SCREEN_EXCLUSIVE_MODE_LOST_EXT` An operation on a swapchain created with `VK_FULL_SCREEN_EXCLUSIVE_APPLICATION_CONTROLLED_EXT` failed as it did not have exlusive full-screen access. This may occur due to implementation-dependent reasons, outside of the application’s control.

- `VK_ERROR_UNKNOWN` An unknown error has occurred; either the application has provided invalid input, or an implementation failure has occurred.

- `VK_ERROR_PIPELINE_COMPILE_REQUIRED_EXT` A pipeline creation failed because some or all of the data necessary to create the pipeline was not pre-compiled.

If a command returns a run time error, unless otherwise specified any output parameters will have undefined contents, except that if the output parameter is a structure with `sType` and `pNext` fields, those fields will be unmodified. Any structures chained from `pNext` will also have undefined contents, except that `sType` and `pNext` will be unmodified.

Out of memory errors do not damage any currently existing Vulkan objects. Objects that have already been successfully created can still be used by the application.

`VK_ERROR_UNKNOWN` will be returned by an implementation when an unexpected error occurs that cannot be attributed to valid behavior of the application and implementation.

| Note If `VK_ERROR_UNKNOWN` is received, the application should be checked against the latest validation layers to verify correct behavior as much as possible. If no issues are identified it could be an implementation issue, and the implementor should be contacted for support. This error should not be expected from any command if application behavior is valid, and if the implementation is bug-free, but it can be returned by any error returning command when that is not the case.

Performance-critical commands generally do not have return codes. If a run time error occurs in such commands, the implementation will defer reporting the error until a specified point. For commands that record into command buffers (`vkCmd*`) run time errors are reported by `vkEndCommandBuffer`.

### 2.8. Numeric Representation and Computation

Implementations normally perform computations in floating-point, and must meet the range and precision requirements defined under “Floating-Point Computation” below.

These requirements only apply to computations performed in Vulkan operations outside of shader execution, such as texture image specification and sampling, and per-fragment operations. Range and precision requirements during shader execution differ and are specified by the Precision and Operation of SPIR-V Instructions section.

In some cases, the representation and/or precision of operations is implicitly limited by the specified format of vertex or texel data consumed by Vulkan. Specific floating-point formats are described later in this section.

#### 2.8.1. Floating-Point Computation

Most floating-point computation is performed in SPIR-V shader modules. The properties of computation within shaders are constrained as defined by the Precision and Operation of SPIR-V Instructions section.

Some floating-point computation is performed outside of shaders, such as viewport and depth range calculations. For these computations, we do not specify how floating-point numbers are to be represented, or the details of how operations on them are performed, but only place minimal requirements on representation and precision as described in the remainder of this section.

| editing-note (Jon, Bug 14966) This is a rat’s nest of complexity, both in terms of describing/enumerating places such computation may take place (other than “not shader code”) and in how implementations may do it. We have consciously deferred the resolution of this issue to post-1.0, and in the meantime, the following language inherited from the OpenGL Specification is inserted as a placeholder. Hopefully it can be tightened up considerably.

We require simply that numbers’ floating-point parts contain enough bits and that their exponent fields are large enough so that individual results of floating-point operations are accurate to about 1 part in 105. The maximum representable magnitude for all floating-point values must be at least 232.

  x × 0 = 0 × x = 0 for any non-infinite and non-NaN x.

  1 × x = x × 1 = x.

  x + 0 = 0 + x = x.

  00 = 1.

Occasionally, further requirements will be specified. Most single-precision floating-point formats meet these requirements.

The special values Inf and -Inf encode values with magnitudes too large to be represented; the special value NaN encodes “Not A Number” values resulting from undefined arithmetic operations such as 0 / 0. Implementations may support Inf and NaN in their floating-point computations.

#### 2.8.2. Floating-Point Format Conversions

When a value is converted to a defined floating-point representation, finite values falling between two representable finite values are rounded to one or the other. The rounding mode is not defined. Finite values whose magnitude is larger than that of any representable finite value may be rounded either to the closest representable finite value or to the appropriately signed infinity. For unsigned destination formats any negative values are converted to zero. Positive infinity is converted to positive infinity; negative infinity is converted to negative infinity in signed formats and to zero in unsigned formats; and any NaN is converted to a NaN.

#### 2.8.3. 16-Bit Floating-Point Numbers

16-bit floating point numbers are defined in the “16-bit floating point numbers” section of the Khronos Data Format Specification.

#### 2.8.4. Unsigned 11-Bit Floating-Point Numbers

Unsigned 11-bit floating point numbers are defined in the “Unsigned 11-bit floating point numbers” section of the Khronos Data Format Specification.

#### 2.8.5. Unsigned 10-Bit Floating-Point Numbers

Unsigned 10-bit floating point numbers are defined in the “Unsigned 10-bit floating point numbers” section of the Khronos Data Format Specification.

#### 2.8.6. General Requirements

Any representable floating-point value in the appropriate format is legal as input to a Vulkan command that requires floating-point data. The result of providing a value that is not a floating-point number to such a command is unspecified, but must not lead to Vulkan interruption or termination. For example, providing a negative zero (where applicable) or a denormalized number to a Vulkan command must yield deterministic results, while providing a NaN or Inf yields unspecified results.

Some calculations require division. In such cases (including implied divisions performed by vector normalization), division by zero produces an unspecified result but must not lead to Vulkan interruption or termination.

### 2.9. Fixed-Point Data Conversions

When generic vertex attributes and pixel color or depth components are represented as integers, they are often (but not always) considered to be normalized. Normalized integer values are treated specially when being converted to and from floating-point values, and are usually referred to as normalized fixed-point.

In the remainder of this section, b denotes the bit width of the fixed-point integer representation. When the integer is one of the types defined by the API, b is the bit width of that type. When the integer comes from an image containing color or depth component texels, b is the number of bits allocated to that component in its specified image format.

The signed and unsigned fixed-point representations are assumed to be b-bit binary two’s-complement integers and binary unsigned integers, respectively.

#### 2.9.1. Conversion from Normalized Fixed-Point to Floating-Point

Unsigned normalized fixed-point integers represent numbers in the range [0,1]. The conversion from an unsigned normalized fixed-point value c to the corresponding floating-point value f is defined as

\[f = { c \over { 2^b - 1 } }\]

Signed normalized fixed-point integers represent numbers in the range [-1,1]. The conversion from a signed normalized fixed-point value c to the corresponding floating-point value f is performed using

\[f = \max\left( {c \over {2^{b-1} - 1}}, -1.0 \right)\]

Only the range [-2b-1 + 1, 2b-1 - 1] is used to represent signed fixed-point values in the range [-1,1]. For example, if b = 8, then the integer value -127 corresponds to -1.0 and the value 127 corresponds to 1.0. Note that while zero is exactly expressible in this representation, one value (-128 in the example) is outside the representable range, and must be clamped before use. This equation is used everywhere that signed normalized fixed-point values are converted to floating-point.

#### 2.9.2. Conversion from Floating-Point to Normalized Fixed-Point

The conversion from a floating-point value f to the corresponding unsigned normalized fixed-point value c is defined by first clamping f to the range [0,1], then computing

  c = convertFloatToUint(f × (2b - 1), b)

where convertFloatToUint}(r,b) returns one of the two unsigned binary integer values with exactly b bits which are closest to the floating-point value r. Implementations should round to nearest. If r is equal to an integer, then that integer value must be returned. In particular, if f is equal to 0.0 or 1.0, then c must be assigned 0 or 2b - 1, respectively.

The conversion from a floating-point value f to the corresponding signed normalized fixed-point value c is performed by clamping f to the range [-1,1], then computing

  c = convertFloatToInt(f × (2b-1 - 1), b)

where convertFloatToInt(r,b) returns one of the two signed two’s-complement binary integer values with exactly b bits which are closest to the floating-point value r. Implementations should round to nearest. If r is equal to an integer, then that integer value must be returned. In particular, if f is equal to -1.0, 0.0, or 1.0, then c must be assigned -(2b-1 - 1), 0, or 2b-1 - 1, respectively.

This equation is used everywhere that floating-point values are converted to signed normalized fixed-point.

### 2.10. Common Object Types

Some types of Vulkan objects are used in many different structures and command parameters, and are described here. These types include offsets, extents, and rectangles.

#### 2.10.1. Offsets

Offsets are used to describe a pixel location within an image or framebuffer, as an (x,y) location for two-dimensional images, or an (x,y,z) location for three-dimensional images.

A two-dimensional offsets is defined by the structure:

    typedef struct VkOffset2D {
        int32_t    x;
        int32_t    y;
    } VkOffset2D;

- `x` is the x offset.

- `y` is the y offset.

A three-dimensional offset is defined by the structure:

    typedef struct VkOffset3D {
        int32_t    x;
        int32_t    y;
        int32_t    z;
    } VkOffset3D;

- `x` is the x offset.

- `y` is the y offset.

- `z` is the z offset.

#### 2.10.2. Extents

Extents are used to describe the size of a rectangular region of pixels within an image or framebuffer, as (width,height) for two-dimensional images, or as (width,height,depth) for three-dimensional images.

A two-dimensional extent is defined by the structure:

    typedef struct VkExtent2D {
        uint32_t    width;
        uint32_t    height;
    } VkExtent2D;

- `width` is the width of the extent.

- `height` is the height of the extent.

A three-dimensional extent is defined by the structure:

    typedef struct VkExtent3D {
        uint32_t    width;
        uint32_t    height;
        uint32_t    depth;
    } VkExtent3D;

- `width` is the width of the extent.

- `height` is the height of the extent.

- `depth` is the depth of the extent.

#### 2.10.3. Rectangles

Rectangles are used to describe a specified rectangular region of pixels within an image or framebuffer. Rectangles include both an offset and an extent of the same dimensionality, as described above. Two-dimensional rectangles are defined by the structure

    typedef struct VkRect2D {
        VkOffset2D    offset;
        VkExtent2D    extent;
    } VkRect2D;

- `offset` is a VkOffset2D specifying the rectangle offset.

- `extent` is a VkExtent2D specifying the rectangle extent.

## 3. Initialization

Before using Vulkan, an application must initialize it by loading the Vulkan commands, and creating a `VkInstance` object.

### 3.1. Command Function Pointers

Vulkan commands are not necessarily exposed by static linking on a platform. Commands to query function pointers for Vulkan commands are described below.

| Note When extensions are promoted or otherwise incorporated into another extension or Vulkan core version, command aliases may be included. Whilst the behavior of each command alias is identical, the behavior of retrieving each alias’s function pointer is not. A function pointer for a given alias can only be retrieved if the extension or version that introduced that alias is supported and enabled, irrespective of whether any other alias is available.

Function pointers for all Vulkan commands can be obtained with the command:

    PFN_vkVoidFunction vkGetInstanceProcAddr(
        VkInstance                                  instance,
        const char*                                 pName);

- `instance` is the instance that the function pointer will be compatible with, or `NULL` for commands not dependent on any instance.

- `pName` is the name of the command to obtain.

`vkGetInstanceProcAddr` itself is obtained in a platform- and loader- specific manner. Typically, the loader library will export this command as a function symbol, so applications can link against the loader library, or load it dynamically and look up the symbol using platform-specific APIs.

The table below defines the various use cases for `vkGetInstanceProcAddr` and expected return value (“fp” is “function pointer”) for each case.

The returned function pointer is of type PFN_vkVoidFunction, and must be cast to the type of the command being queried.

Table 1. vkGetInstanceProcAddr behavior
`instance` | `pName` | return value
--- | --- | ---
*1 | `NULL` | undefined
invalid non-`NULL` instance | *1 | undefined
`NULL` | vkEnumerateInstanceVersion | fp
`NULL` | vkEnumerateInstanceExtensionProperties | fp
`NULL` | vkEnumerateInstanceLayerProperties | fp
`NULL` | vkCreateInstance | fp
instance | core Vulkan command | fp2
instance | enabled instance extension commands for `instance` | fp2
instance | available device extension3 commands for `instance` | fp2
any other case, not covered above | `NULL`

1

  "*" means any representable value for the parameter (including valid values, invalid values, and `NULL`).

2

  The returned function pointer must only be called with a dispatchable object (the first parameter) that is `instance` or a child of `instance`, e.g. VkInstance, VkPhysicalDevice, VkDevice, VkQueue, or VkCommandBuffer.

3

  An “available device extension” is a device extension supported by any physical device enumerated by `instance`.

Valid Usage (Implicit)

- If `instance` is not `NULL`, `instance` must be a valid VkInstance handle

- `pName` must be a null-terminated UTF-8 string

In order to support systems with multiple Vulkan implementations, the function pointers returned by `vkGetInstanceProcAddr` may point to dispatch code that calls a different real implementation for different VkDevice objects or their child objects. The overhead of the internal dispatch for VkDevice objects can be avoided by obtaining device-specific function pointers for any commands that use a device or device-child object as their dispatchable object. Such function pointers can be obtained with the command:

    PFN_vkVoidFunction vkGetDeviceProcAddr(
        VkDevice                                    device,
        const char*                                 pName);

The table below defines the various use cases for `vkGetDeviceProcAddr` and expected return value for each case.

The returned function pointer is of type PFN_vkVoidFunction, and must be cast to the type of the command being queried. The function pointer must only be called with a dispatchable object (the first parameter) that is `device` or a child of `device`.

Table 2. vkGetDeviceProcAddr behavior
`device` | `pName` | return value
--- | --- | ---
`NULL` | *1 | undefined
invalid device | *1 | undefined
device | `NULL` | undefined
device | core device-level Vulkan command | fp2
device | enabled extension device-level commands | fp2
any other case, not covered above | `NULL`

1

  "*" means any representable value for the parameter (including valid values, invalid values, and `NULL`).

2

  The returned function pointer must only be called with a dispatchable object (the first parameter) that is `device` or a child of `device` e.g. VkDevice, VkQueue, or VkCommandBuffer.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pName` must be a null-terminated UTF-8 string

The definition of PFN_vkVoidFunction is:

    typedef void (VKAPI_PTR *PFN_vkVoidFunction)(void);

#### 3.1.1. Extending Physical Device Core Functionality

New core physical-device-level functionality can be used when the physical-device version is greater than or equal to the version of Vulkan that added the new functionality. The Vulkan version supported by a physical device can be obtained by calling vkGetPhysicalDeviceProperties.

#### 3.1.2. Extending Physical Device From Device Extensions

When the `VK_KHR_get_physical_device_properties2` extension is enabled, or when both the instance and the physical-device versions are at least 1.1, physical-device-level functionality of a device extension can be used with a physical device if the corresponding extension is enumerated by vkEnumerateDeviceExtensionProperties for that physical device, even before a logical device has been created.

To obtain a function pointer for a physical-device-level command from a device extension, an application can use vkGetInstanceProcAddr. This function pointer may point to dispatch code, which calls a different real implementation for different `VkPhysicalDevice` objects. Applications must not use a VkPhysicalDevice in any command added by an extension or core version that is not supported by that physical device.

Device extensions may define structures that can be added to the `pNext` chain of physical-device-level commands.

### 3.2. Instances

There is no global state in Vulkan and all per-application state is stored in a `VkInstance` object. Creating a `VkInstance` object initializes the Vulkan library and allows the application to pass information about itself to the implementation.

Instances are represented by `VkInstance` handles:

    VK_DEFINE_HANDLE(VkInstance)

To query the version of instance-level functionality supported by the implementation, call:

    VkResult vkEnumerateInstanceVersion(
        uint32_t*                                   pApiVersion);

- `pApiVersion` is a pointer to a `uint32_t`, which is the version of Vulkan supported by instance-level functionality, encoded as described in Version Numbers.

Valid Usage (Implicit)

- `pApiVersion` must be a valid pointer to a `uint32_t` value

Return Codes

Success

  - `VK_SUCCESS`

To create an instance object, call:

    VkResult vkCreateInstance(
        const VkInstanceCreateInfo*                 pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkInstance*                                 pInstance);

- `pCreateInfo` is a pointer to a VkInstanceCreateInfo structure controlling creation of the instance.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pInstance` points a VkInstance handle in which the resulting instance is returned.

`vkCreateInstance` verifies that the requested layers exist. If not, `vkCreateInstance` will return `VK_ERROR_LAYER_NOT_PRESENT`. Next `vkCreateInstance` verifies that the requested extensions are supported (e.g. in the implementation or in any enabled instance layer) and if any requested extension is not supported, `vkCreateInstance` must return `VK_ERROR_EXTENSION_NOT_PRESENT`. After verifying and enabling the instance layers and extensions the `VkInstance` object is created and returned to the application. If a requested extension is only supported by a layer, both the layer and the extension need to be specified at `vkCreateInstance` time for the creation to succeed.

Valid Usage

- All required extensions for each extension in the VkInstanceCreateInfo::`ppEnabledExtensionNames` list must also be present in that list.

Valid Usage (Implicit)

- `pCreateInfo` must be a valid pointer to a valid VkInstanceCreateInfo structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pInstance` must be a valid pointer to a VkInstance handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_INITIALIZATION_FAILED`

  - `VK_ERROR_LAYER_NOT_PRESENT`

  - `VK_ERROR_EXTENSION_NOT_PRESENT`

  - `VK_ERROR_INCOMPATIBLE_DRIVER`

The `VkInstanceCreateInfo` structure is defined as:

    typedef struct VkInstanceCreateInfo {
        VkStructureType             sType;
        const void*                 pNext;
        VkInstanceCreateFlags       flags;
        const VkApplicationInfo*    pApplicationInfo;
        uint32_t                    enabledLayerCount;
        const char* const*          ppEnabledLayerNames;
        uint32_t                    enabledExtensionCount;
        const char* const*          ppEnabledExtensionNames;
    } VkInstanceCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `pApplicationInfo` is `NULL` or a pointer to a `VkApplicationInfo` structure. If not `NULL`, this information helps implementations recognize behavior inherent to classes of applications. VkApplicationInfo is defined in detail below.

- `enabledLayerCount` is the number of global layers to enable.

- `ppEnabledLayerNames` is a pointer to an array of `enabledLayerCount` null-terminated UTF-8 strings containing the names of layers to enable for the created instance. The layers are loaded in the order they are listed in this array, with the first array element being the closest to the application, and the last array element being the closest to the driver. See the Layers section for further details.

- `enabledExtensionCount` is the number of global extensions to enable.

- `ppEnabledExtensionNames` is a pointer to an array of `enabledExtensionCount` null-terminated UTF-8 strings containing the names of extensions to enable.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkDebugReportCallbackCreateInfoEXT, VkDebugUtilsMessengerCreateInfoEXT, VkValidationFeaturesEXT, or VkValidationFlagsEXT

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be `0`

- If `pApplicationInfo` is not `NULL`, `pApplicationInfo` must be a valid pointer to a valid VkApplicationInfo structure

- If `enabledLayerCount` is not `0`, `ppEnabledLayerNames` must be a valid pointer to an array of `enabledLayerCount` null-terminated UTF-8 strings

- If `enabledExtensionCount` is not `0`, `ppEnabledExtensionNames` must be a valid pointer to an array of `enabledExtensionCount` null-terminated UTF-8 strings

    typedef VkFlags VkInstanceCreateFlags;

`VkInstanceCreateFlags` is a bitmask type for setting a mask, but is currently reserved for future use.

When creating a Vulkan instance for which you wish to disable validation checks, add a VkValidationFlagsEXT structure to the `pNext` chain of the VkInstanceCreateInfo structure, specifying the checks to be disabled.

    typedef struct VkValidationFlagsEXT {
        VkStructureType                sType;
        const void*                    pNext;
        uint32_t                       disabledValidationCheckCount;
        const VkValidationCheckEXT*    pDisabledValidationChecks;
    } VkValidationFlagsEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `disabledValidationCheckCount` is the number of checks to disable.

- `pDisabledValidationChecks` is a pointer to an array of VkValidationCheckEXT values specifying the validation checks to be disabled.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_VALIDATION_FLAGS_EXT`

- `pDisabledValidationChecks` must be a valid pointer to an array of `disabledValidationCheckCount` valid VkValidationCheckEXT values

- `disabledValidationCheckCount` must be greater than `0`

Possible values of elements of the VkValidationFlagsEXT::`pDisabledValidationChecks` array, specifying validation checks to be disabled, are:

    typedef enum VkValidationCheckEXT {
        VK_VALIDATION_CHECK_ALL_EXT = 0,
        VK_VALIDATION_CHECK_SHADERS_EXT = 1,
        VK_VALIDATION_CHECK_MAX_ENUM_EXT = 0x7FFFFFFF
    } VkValidationCheckEXT;

- `VK_VALIDATION_CHECK_ALL_EXT` specifies that all validation checks are disabled.

- `VK_VALIDATION_CHECK_SHADERS_EXT` specifies that shader validation is disabled.

When creating a Vulkan instance for which you wish to enable or disable specific validation features, add a VkValidationFeaturesEXT structure to the `pNext` chain of the VkInstanceCreateInfo structure, specifying the features to be enabled or disabled.

    typedef struct VkValidationFeaturesEXT {
        VkStructureType                         sType;
        const void*                             pNext;
        uint32_t                                enabledValidationFeatureCount;
        const VkValidationFeatureEnableEXT*     pEnabledValidationFeatures;
        uint32_t                                disabledValidationFeatureCount;
        const VkValidationFeatureDisableEXT*    pDisabledValidationFeatures;
    } VkValidationFeaturesEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `enabledValidationFeatureCount` is the number of features to enable.

- `pEnabledValidationFeatures` is a pointer to an array of VkValidationFeatureEnableEXT values specifying the validation features to be enabled.

- `disabledValidationFeatureCount` is the number of features to disable.

- `pDisabledValidationFeatures` is a pointer to an array of VkValidationFeatureDisableEXT values specifying the validation features to be disabled.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_VALIDATION_FEATURES_EXT`

- If `enabledValidationFeatureCount` is not `0`, `pEnabledValidationFeatures` must be a valid pointer to an array of `enabledValidationFeatureCount` valid VkValidationFeatureEnableEXT values

- If `disabledValidationFeatureCount` is not `0`, `pDisabledValidationFeatures` must be a valid pointer to an array of `disabledValidationFeatureCount` valid VkValidationFeatureDisableEXT values

Possible values of elements of the VkValidationFeaturesEXT::`pEnabledValidationFeatures` array, specifying validation features to be enabled, are:

    typedef enum VkValidationFeatureEnableEXT {
        VK_VALIDATION_FEATURE_ENABLE_GPU_ASSISTED_EXT = 0,
        VK_VALIDATION_FEATURE_ENABLE_GPU_ASSISTED_RESERVE_BINDING_SLOT_EXT = 1,
        VK_VALIDATION_FEATURE_ENABLE_BEST_PRACTICES_EXT = 2,
        VK_VALIDATION_FEATURE_ENABLE_DEBUG_PRINTF_EXT = 3,
        VK_VALIDATION_FEATURE_ENABLE_MAX_ENUM_EXT = 0x7FFFFFFF
    } VkValidationFeatureEnableEXT;

- `VK_VALIDATION_FEATURE_ENABLE_GPU_ASSISTED_EXT` specifies that GPU-assisted validation is enabled. Activating this feature instruments shader programs to generate additional diagnostic data. This feature is disabled by default.

- `VK_VALIDATION_FEATURE_ENABLE_GPU_ASSISTED_RESERVE_BINDING_SLOT_EXT` specifies that the validation layers reserve a descriptor set binding slot for their own use. The layer reports a value for VkPhysicalDeviceLimits::`maxBoundDescriptorSets` that is one less than the value reported by the device. If the device supports the binding of only one descriptor set, the validation layer does not perform GPU-assisted validation. This feature is disabled by default. The GPU-assisted validation feature must be enabled in order to use this feature.

- `VK_VALIDATION_FEATURE_ENABLE_BEST_PRACTICES_EXT` specifies that Vulkan best-practices validation is enabled. Activating this feature enables the output of warnings related to common misuse of the API, but which are not explicitly prohibited by the specification. This feature is disabled by default.

- `VK_VALIDATION_FEATURE_ENABLE_DEBUG_PRINTF_EXT` specifies that the layers will process `debugPrintfEXT` operations in shaders and send the resulting output to the debug callback. This feature is disabled by default. `VK_VALIDATION_FEATURE_ENABLE_DEBUG_PRINTF_EXT` must never be enabled when `VK_VALIDATION_FEATURE_ENABLE_GPU_ASSISTED_EXT` is enabled.

Possible values of elements of the VkValidationFeaturesEXT::`pDisabledValidationFeatures` array, specifying validation features to be disabled, are:

    typedef enum VkValidationFeatureDisableEXT {
        VK_VALIDATION_FEATURE_DISABLE_ALL_EXT = 0,
        VK_VALIDATION_FEATURE_DISABLE_SHADERS_EXT = 1,
        VK_VALIDATION_FEATURE_DISABLE_THREAD_SAFETY_EXT = 2,
        VK_VALIDATION_FEATURE_DISABLE_API_PARAMETERS_EXT = 3,
        VK_VALIDATION_FEATURE_DISABLE_OBJECT_LIFETIMES_EXT = 4,
        VK_VALIDATION_FEATURE_DISABLE_CORE_CHECKS_EXT = 5,
        VK_VALIDATION_FEATURE_DISABLE_UNIQUE_HANDLES_EXT = 6,
        VK_VALIDATION_FEATURE_DISABLE_MAX_ENUM_EXT = 0x7FFFFFFF
    } VkValidationFeatureDisableEXT;

- `VK_VALIDATION_FEATURE_DISABLE_ALL_EXT` specifies that all validation checks are disabled.

- `VK_VALIDATION_FEATURE_DISABLE_SHADERS_EXT` specifies that shader validation is disabled. This feature is enabled by default.

- `VK_VALIDATION_FEATURE_DISABLE_THREAD_SAFETY_EXT` specifies that thread safety validation is disabled. This feature is enabled by default.

- `VK_VALIDATION_FEATURE_DISABLE_API_PARAMETERS_EXT` specifies that stateless parameter validation is disabled. This feature is enabled by default.

- `VK_VALIDATION_FEATURE_DISABLE_OBJECT_LIFETIMES_EXT` specifies that object lifetime validation is disabled. This feature is enabled by default.

- `VK_VALIDATION_FEATURE_DISABLE_CORE_CHECKS_EXT` specifies that core validation checks are disabled. This feature is enabled by default. If this feature is disabled, the shader validation and GPU-assisted validation features are also disabled.

- `VK_VALIDATION_FEATURE_DISABLE_UNIQUE_HANDLES_EXT` specifies that protection against duplicate non-dispatchable object handles is disabled. This feature is enabled by default.

| Note Disabling checks such as parameter validation and object lifetime validation prevents the reporting of error conditions that can cause other validation checks to behave incorrectly or crash. Some validation checks assume that their inputs are already valid and do not always revalidate them.

| Note The `VK_EXT_validation_features` extension subsumes all the functionality provided in the `VK_EXT_validation_flags` extension.

The `VkApplicationInfo` structure is defined as:

    typedef struct VkApplicationInfo {
        VkStructureType    sType;
        const void*        pNext;
        const char*        pApplicationName;
        uint32_t           applicationVersion;
        const char*        pEngineName;
        uint32_t           engineVersion;
        uint32_t           apiVersion;
    } VkApplicationInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `pApplicationName` is `NULL` or is a pointer to a null-terminated UTF-8 string containing the name of the application.

- `applicationVersion` is an unsigned integer variable containing the developer-supplied version number of the application.

- `pEngineName` is `NULL` or is a pointer to a null-terminated UTF-8 string containing the name of the engine (if any) used to create the application.

- `engineVersion` is an unsigned integer variable containing the developer-supplied version number of the engine used to create the application.

- `apiVersion` must be the highest version of Vulkan that the application is designed to use, encoded as described in Version Numbers. The patch version number specified in `apiVersion` is ignored when creating an instance object. Only the major and minor versions of the instance must match those requested in `apiVersion`.

Vulkan 1.0 implementations were required to return `VK_ERROR_INCOMPATIBLE_DRIVER` if `apiVersion` was larger than 1.0. Implementations that support Vulkan 1.1 or later must not return `VK_ERROR_INCOMPATIBLE_DRIVER` for any value of `apiVersion`.

| Note Because Vulkan 1.0 implementations may fail with `VK_ERROR_INCOMPATIBLE_DRIVER`, applications should determine the version of Vulkan available before calling vkCreateInstance. If the vkGetInstanceProcAddr returns `NULL` for vkEnumerateInstanceVersion, it is a Vulkan 1.0 implementation. Otherwise, the application can call vkEnumerateInstanceVersion to determine the version of Vulkan.

As long as the instance supports at least Vulkan 1.1, an application can use different versions of Vulkan with an instance than it does with a device or physical device.

| Note The Khronos validation layers will treat `apiVersion` as the highest API version the application targets, and will validate API usage against the minimum of that version and the implementation version (instance or device, depending on context). If an application tries to use functionality from a greater version than this, a validation error will be triggered. For example, if the instance supports Vulkan 1.1 and three physical devices support Vulkan 1.0, Vulkan 1.1, and Vulkan 1.2, respectively, and if the application sets `apiVersion` to 1.2, the application can use the following versions of Vulkan: Vulkan 1.0 can be used with the instance and with all physical devices. Vulkan 1.1 can be used with the instance and with the physical devices that support Vulkan 1.1 and Vulkan 1.2. Vulkan 1.2 can be used with the physical device that supports Vulkan 1.2. If we modify the above example so that the application sets `apiVersion` to 1.1, then the application must not use Vulkan 1.2 functionality on the physical device that supports Vulkan 1.2.

Implicit layers must be disabled if they do not support a version at least as high as `apiVersion`. See the Vulkan Loader Specification and Architecture Overview document for additional information.

| Note Providing a `NULL` `VkInstanceCreateInfo`::`pApplicationInfo` or providing an `apiVersion` of 0 is equivalent to providing an `apiVersion` of `VK_MAKE_VERSION(1,0,0)`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_APPLICATION_INFO`

- `pNext` must be `NULL`

- If `pApplicationName` is not `NULL`, `pApplicationName` must be a null-terminated UTF-8 string

- If `pEngineName` is not `NULL`, `pEngineName` must be a null-terminated UTF-8 string

To destroy an instance, call:

    void vkDestroyInstance(
        VkInstance                                  instance,
        const VkAllocationCallbacks*                pAllocator);

- `instance` is the handle of the instance to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage

- All child objects created using `instance` must have been destroyed prior to destroying `instance`

- If `VkAllocationCallbacks` were provided when `instance` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `instance` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- If `instance` is not `NULL`, `instance` must be a valid VkInstance handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

Host Synchronization

- Host access to `instance` must be externally synchronized

## 4. Devices and Queues

Once Vulkan is initialized, devices and queues are the primary objects used to interact with a Vulkan implementation.

Vulkan separates the concept of physical and logical devices. A physical device usually represents a single complete implementation of Vulkan (excluding instance-level functionality) available to the host, of which there are a finite number. A logical device represents an instance of that implementation with its own state and resources independent of other logical devices.

Physical devices are represented by `VkPhysicalDevice` handles:

    VK_DEFINE_HANDLE(VkPhysicalDevice)

### 4.1. Physical Devices

To retrieve a list of physical device objects representing the physical devices installed in the system, call:

    VkResult vkEnumeratePhysicalDevices(
        VkInstance                                  instance,
        uint32_t*                                   pPhysicalDeviceCount,
        VkPhysicalDevice*                           pPhysicalDevices);

- `instance` is a handle to a Vulkan instance previously created with vkCreateInstance.

- `pPhysicalDeviceCount` is a pointer to an integer related to the number of physical devices available or queried, as described below.

- `pPhysicalDevices` is either `NULL` or a pointer to an array of `VkPhysicalDevice` handles.

If `pPhysicalDevices` is `NULL`, then the number of physical devices available is returned in `pPhysicalDeviceCount`. Otherwise, `pPhysicalDeviceCount` must point to a variable set by the user to the number of elements in the `pPhysicalDevices` array, and on return the variable is overwritten with the number of handles actually written to `pPhysicalDevices`. If `pPhysicalDeviceCount` is less than the number of physical devices available, at most `pPhysicalDeviceCount` structures will be written. If `pPhysicalDeviceCount` is smaller than the number of physical devices available, `VK_INCOMPLETE` will be returned instead of `VK_SUCCESS`, to indicate that not all the available physical devices were returned.

Valid Usage (Implicit)

- `instance` must be a valid VkInstance handle

- `pPhysicalDeviceCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pPhysicalDeviceCount` is not `0`, and `pPhysicalDevices` is not `NULL`, `pPhysicalDevices` must be a valid pointer to an array of `pPhysicalDeviceCount` VkPhysicalDevice handles

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_INITIALIZATION_FAILED`

To query general properties of physical devices once enumerated, call:

    void vkGetPhysicalDeviceProperties(
        VkPhysicalDevice                            physicalDevice,
        VkPhysicalDeviceProperties*                 pProperties);

- `physicalDevice` is the handle to the physical device whose properties will be queried.

- `pProperties` is a pointer to a VkPhysicalDeviceProperties structure in which properties are returned.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pProperties` must be a valid pointer to a VkPhysicalDeviceProperties structure

The `VkPhysicalDeviceProperties` structure is defined as:

    typedef struct VkPhysicalDeviceProperties {
        uint32_t                            apiVersion;
        uint32_t                            driverVersion;
        uint32_t                            vendorID;
        uint32_t                            deviceID;
        VkPhysicalDeviceType                deviceType;
        char                                deviceName[VK_MAX_PHYSICAL_DEVICE_NAME_SIZE];
        uint8_t                             pipelineCacheUUID[VK_UUID_SIZE];
        VkPhysicalDeviceLimits              limits;
        VkPhysicalDeviceSparseProperties    sparseProperties;
    } VkPhysicalDeviceProperties;

- `apiVersion` is the version of Vulkan supported by the device, encoded as described in Version Numbers.

- `driverVersion` is the vendor-specified version of the driver.

- `vendorID` is a unique identifier for the vendor (see below) of the physical device.

- `deviceID` is a unique identifier for the physical device among devices available from the vendor.

- `deviceType` is a VkPhysicalDeviceType specifying the type of device.

- `deviceName` is an array of `VK_MAX_PHYSICAL_DEVICE_NAME_SIZE` `char` containing a null-terminated UTF-8 string which is the name of the device.

- `pipelineCacheUUID` is an array of `VK_UUID_SIZE` `uint8_t` values representing a universally unique identifier for the device.

- `limits` is the VkPhysicalDeviceLimits structure specifying device-specific limits of the physical device. See Limits for details.

- `sparseProperties` is the VkPhysicalDeviceSparseProperties structure specifying various sparse related properties of the physical device. See Sparse Properties for details.

| Note The value of `apiVersion` may be different than the version returned by vkEnumerateInstanceVersion; either higher or lower. In such cases, the application must not use functionality that exceeds the version of Vulkan associated with a given object. The `pApiVersion` parameter returned by vkEnumerateInstanceVersion is the version associated with a VkInstance and its children, except for a VkPhysicalDevice and its children. `VkPhysicalDeviceProperties`::`apiVersion` is the version associated with a VkPhysicalDevice and its children.

The `vendorID` and `deviceID` fields are provided to allow applications to adapt to device characteristics that are not adequately exposed by other Vulkan queries.

| Note These may include performance profiles, hardware errata, or other characteristics.

The vendor identified by `vendorID` is the entity responsible for the most salient characteristics of the underlying implementation of the VkPhysicalDevice being queried.

| Note For example, in the case of a discrete GPU implementation, this should be the GPU chipset vendor. In the case of a hardware accelerator integrated into a system-on-chip (SoC), this should be the supplier of the silicon IP used to create the accelerator.

If the vendor has a PCI vendor ID, the low 16 bits of `vendorID` must contain that PCI vendor ID, and the remaining bits must be set to zero. Otherwise, the value returned must be a valid Khronos vendor ID, obtained as described in the Vulkan Documentation and Extensions: Procedures and Conventions document in the section “Registering a Vendor ID with Khronos”. Khronos vendor IDs are allocated starting at 0x10000, to distinguish them from the PCI vendor ID namespace. Khronos vendor IDs are symbolically defined in the VkVendorId type.

The vendor is also responsible for the value returned in `deviceID`. If the implementation is driven primarily by a PCI device with a PCI device ID, the low 16 bits of `deviceID` must contain that PCI device ID, and the remaining bits must be set to zero. Otherwise, the choice of what values to return may be dictated by operating system or platform policies - but should uniquely identify both the device version and any major configuration options (for example, core count in the case of multicore devices).

| Note The same device ID should be used for all physical implementations of that device version and configuration. For example, all uses of a specific silicon IP GPU version and configuration should use the same device ID, even if those uses occur in different SoCs.

Khronos vendor IDs which may be returned in VkPhysicalDeviceProperties::`vendorID` are:

    typedef enum VkVendorId {
        VK_VENDOR_ID_VIV = 0x10001,
        VK_VENDOR_ID_VSI = 0x10002,
        VK_VENDOR_ID_KAZAN = 0x10003,
        VK_VENDOR_ID_CODEPLAY = 0x10004,
        VK_VENDOR_ID_MAX_ENUM = 0x7FFFFFFF
    } VkVendorId;

| Note Khronos vendor IDs may be allocated by vendors at any time. Only the latest canonical versions of this Specification, of the corresponding `vk.xml` API Registry, and of the corresponding `vulkan_core.h` header file must contain all reserved Khronos vendor IDs. Only Khronos vendor IDs are given symbolic names at present. PCI vendor IDs returned by the implementation can be looked up in the PCI-SIG database.

The physical device types which may be returned in VkPhysicalDeviceProperties::`deviceType` are:

    typedef enum VkPhysicalDeviceType {
        VK_PHYSICAL_DEVICE_TYPE_OTHER = 0,
        VK_PHYSICAL_DEVICE_TYPE_INTEGRATED_GPU = 1,
        VK_PHYSICAL_DEVICE_TYPE_DISCRETE_GPU = 2,
        VK_PHYSICAL_DEVICE_TYPE_VIRTUAL_GPU = 3,
        VK_PHYSICAL_DEVICE_TYPE_CPU = 4,
        VK_PHYSICAL_DEVICE_TYPE_MAX_ENUM = 0x7FFFFFFF
    } VkPhysicalDeviceType;

- `VK_PHYSICAL_DEVICE_TYPE_OTHER` - the device does not match any other available types.

- `VK_PHYSICAL_DEVICE_TYPE_INTEGRATED_GPU` - the device is typically one embedded in or tightly coupled with the host.

- `VK_PHYSICAL_DEVICE_TYPE_DISCRETE_GPU` - the device is typically a separate processor connected to the host via an interlink.

- `VK_PHYSICAL_DEVICE_TYPE_VIRTUAL_GPU` - the device is typically a virtual node in a virtualization environment.

- `VK_PHYSICAL_DEVICE_TYPE_CPU` - the device is typically running on the same processors as the host.

The physical device type is advertised for informational purposes only, and does not directly affect the operation of the system. However, the device type may correlate with other advertised properties or capabilities of the system, such as how many memory heaps there are.

To query general properties of physical devices once enumerated, call:

    void vkGetPhysicalDeviceProperties2(
        VkPhysicalDevice                            physicalDevice,
        VkPhysicalDeviceProperties2*                pProperties);

or the equivalent command

    void vkGetPhysicalDeviceProperties2KHR(
        VkPhysicalDevice                            physicalDevice,
        VkPhysicalDeviceProperties2*                pProperties);

- `physicalDevice` is the handle to the physical device whose properties will be queried.

- `pProperties` is a pointer to a VkPhysicalDeviceProperties2 structure in which properties are returned.

Each structure in `pProperties` and its `pNext` chain contain members corresponding to properties or implementation-dependent limits. `vkGetPhysicalDeviceProperties2` writes each member to a value indicating the value of that property or limit.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pProperties` must be a valid pointer to a VkPhysicalDeviceProperties2 structure

The `VkPhysicalDeviceProperties2` structure is defined as:

    typedef struct VkPhysicalDeviceProperties2 {
        VkStructureType               sType;
        void*                         pNext;
        VkPhysicalDeviceProperties    properties;
    } VkPhysicalDeviceProperties2;

or the equivalent

    typedef VkPhysicalDeviceProperties2 VkPhysicalDeviceProperties2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `properties` is a VkPhysicalDeviceProperties structure describing properties of the physical device. This structure is written with the same values as if it were written by vkGetPhysicalDeviceProperties.

The `pNext` chain of this structure is used to extend the structure with properties defined by extensions.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROPERTIES_2`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkPhysicalDeviceBlendOperationAdvancedPropertiesEXT, VkPhysicalDeviceConservativeRasterizationPropertiesEXT, VkPhysicalDeviceCooperativeMatrixPropertiesNV, VkPhysicalDeviceDepthStencilResolveProperties, VkPhysicalDeviceDescriptorIndexingProperties, VkPhysicalDeviceDeviceGeneratedCommandsPropertiesNV, VkPhysicalDeviceDiscardRectanglePropertiesEXT, VkPhysicalDeviceDriverProperties, VkPhysicalDeviceExternalMemoryHostPropertiesEXT, VkPhysicalDeviceFloatControlsProperties, VkPhysicalDeviceFragmentDensityMapPropertiesEXT, VkPhysicalDeviceIDProperties, VkPhysicalDeviceInlineUniformBlockPropertiesEXT, VkPhysicalDeviceLineRasterizationPropertiesEXT, VkPhysicalDeviceMaintenance3Properties, VkPhysicalDeviceMeshShaderPropertiesNV, VkPhysicalDeviceMultiviewPerViewAttributesPropertiesNVX, VkPhysicalDeviceMultiviewProperties, VkPhysicalDevicePCIBusInfoPropertiesEXT, VkPhysicalDevicePerformanceQueryPropertiesKHR, VkPhysicalDevicePointClippingProperties, VkPhysicalDeviceProtectedMemoryProperties, VkPhysicalDevicePushDescriptorPropertiesKHR, VkPhysicalDeviceRayTracingPropertiesKHR, VkPhysicalDeviceRayTracingPropertiesNV, VkPhysicalDeviceSampleLocationsPropertiesEXT, VkPhysicalDeviceSamplerFilterMinmaxProperties, VkPhysicalDeviceShaderCoreProperties2AMD, VkPhysicalDeviceShaderCorePropertiesAMD, VkPhysicalDeviceShaderSMBuiltinsPropertiesNV, VkPhysicalDeviceShadingRateImagePropertiesNV, VkPhysicalDeviceSubgroupProperties, VkPhysicalDeviceSubgroupSizeControlPropertiesEXT, VkPhysicalDeviceTexelBufferAlignmentPropertiesEXT, VkPhysicalDeviceTimelineSemaphoreProperties, VkPhysicalDeviceTransformFeedbackPropertiesEXT, VkPhysicalDeviceVertexAttributeDivisorPropertiesEXT, VkPhysicalDeviceVulkan11Properties, or VkPhysicalDeviceVulkan12Properties

- The `sType` value of each struct in the `pNext` chain must be unique

To query the properties of the driver corresponding to Vulkan 1.1 functionality, add VkPhysicalDeviceVulkan11Properties to the `pNext` chain of the VkPhysicalDeviceProperties2 structure.

The `VkPhysicalDeviceVulkan11Properties` structure is defined as:

    typedef struct VkPhysicalDeviceVulkan11Properties {
        VkStructureType            sType;
        void*                      pNext;
        uint8_t                    deviceUUID[VK_UUID_SIZE];
        uint8_t                    driverUUID[VK_UUID_SIZE];
        uint8_t                    deviceLUID[VK_LUID_SIZE];
        uint32_t                   deviceNodeMask;
        VkBool32                   deviceLUIDValid;
        uint32_t                   subgroupSize;
        VkShaderStageFlags         subgroupSupportedStages;
        VkSubgroupFeatureFlags     subgroupSupportedOperations;
        VkBool32                   subgroupQuadOperationsInAllStages;
        VkPointClippingBehavior    pointClippingBehavior;
        uint32_t                   maxMultiviewViewCount;
        uint32_t                   maxMultiviewInstanceIndex;
        VkBool32                   protectedNoFault;
        uint32_t                   maxPerSetDescriptors;
        VkDeviceSize               maxMemoryAllocationSize;
    } VkPhysicalDeviceVulkan11Properties;

- `deviceUUID` is an array of `VK_UUID_SIZE` `uint8_t` values representing a universally unique identifier for the device.

- `driverUUID` is an array of `VK_UUID_SIZE` `uint8_t` values representing a universally unique identifier for the driver build in use by the device.

- `deviceLUID` is an array of `VK_LUID_SIZE` `uint8_t` values representing a locally unique identifier for the device.

- `deviceNodeMask` is a `uint32_t` bitfield identifying the node within a linked device adapter corresponding to the device.

- `deviceLUIDValid` is a boolean value that will be `VK_TRUE` if `deviceLUID` contains a valid LUID and `deviceNodeMask` contains a valid node mask, and `VK_FALSE` if they do not.

- `subgroupSize` is the default number of invocations in each subgroup. `subgroupSize` is at least 1 if any of the physical device’s queues support `VK_QUEUE_GRAPHICS_BIT` or `VK_QUEUE_COMPUTE_BIT`. `subgroupSize` is a power-of-two.

- `subgroupSupportedStages` is a bitfield of VkShaderStageFlagBits describing the shader stages that subgroup operations are supported in. `subgroupSupportedStages` will have the `VK_SHADER_STAGE_COMPUTE_BIT` bit set if any of the physical device’s queues support `VK_QUEUE_COMPUTE_BIT`.

- `subgroupSupportedOperations` is a bitmask of VkSubgroupFeatureFlagBits specifying the sets of subgroup operations supported on this device. `subgroupSupportedOperations` will have the `VK_SUBGROUP_FEATURE_BASIC_BIT` bit set if any of the physical device’s queues support `VK_QUEUE_GRAPHICS_BIT` or `VK_QUEUE_COMPUTE_BIT`.

- `subgroupQuadOperationsInAllStages` is a boolean specifying whether quad subgroup operations are available in all stages, or are restricted to fragment and compute stages.

- `pointClippingBehavior` is a VkPointClippingBehavior value specifying the point clipping behavior supported by the implementation.

- `maxMultiviewViewCount` is one greater than the maximum view index that can be used in a subpass.

- `maxMultiviewInstanceIndex` is the maximum valid value of instance index allowed to be generated by a drawing command recorded within a subpass of a multiview render pass instance.

- `protectedNoFault` specifies the behavior of the implementation when protected memory access rules are broken. If `protectedNoFault` is `VK_TRUE`, breaking those rules will not result in process termination or device loss.

- `maxPerSetDescriptors` is a maximum number of descriptors (summed over all descriptor types) in a single descriptor set that is guaranteed to satisfy any implementation-dependent constraints on the size of a descriptor set itself. Applications can query whether a descriptor set that goes beyond this limit is supported using vkGetDescriptorSetLayoutSupport.

- `maxMemoryAllocationSize` is the maximum size of a memory allocation that can be created, even if there is more space available in the heap.

The members of `VkPhysicalDeviceVulkan11Properties` must have the same values as the corresponding members of VkPhysicalDeviceIDProperties, VkPhysicalDeviceSubgroupProperties, VkPhysicalDevicePointClippingProperties, VkPhysicalDeviceMultiviewProperties, VkPhysicalDeviceProtectedMemoryProperties, and VkPhysicalDeviceMaintenance3Properties.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VULKAN_1_1_PROPERTIES`

- `pointClippingBehavior` must be a valid VkPointClippingBehavior value

To query the properties of the driver corresponding to Vulkan 1.2 functionality, add VkPhysicalDeviceVulkan12Properties to the `pNext` chain of the VkPhysicalDeviceProperties2 structure.

The `VkPhysicalDeviceVulkan12Properties` structure is defined as:

    typedef struct VkPhysicalDeviceVulkan12Properties {
        VkStructureType                      sType;
        void*                                pNext;
        VkDriverId                           driverID;
        char                                 driverName[VK_MAX_DRIVER_NAME_SIZE];
        char                                 driverInfo[VK_MAX_DRIVER_INFO_SIZE];
        VkConformanceVersion                 conformanceVersion;
        VkShaderFloatControlsIndependence    denormBehaviorIndependence;
        VkShaderFloatControlsIndependence    roundingModeIndependence;
        VkBool32                             shaderSignedZeroInfNanPreserveFloat16;
        VkBool32                             shaderSignedZeroInfNanPreserveFloat32;
        VkBool32                             shaderSignedZeroInfNanPreserveFloat64;
        VkBool32                             shaderDenormPreserveFloat16;
        VkBool32                             shaderDenormPreserveFloat32;
        VkBool32                             shaderDenormPreserveFloat64;
        VkBool32                             shaderDenormFlushToZeroFloat16;
        VkBool32                             shaderDenormFlushToZeroFloat32;
        VkBool32                             shaderDenormFlushToZeroFloat64;
        VkBool32                             shaderRoundingModeRTEFloat16;
        VkBool32                             shaderRoundingModeRTEFloat32;
        VkBool32                             shaderRoundingModeRTEFloat64;
        VkBool32                             shaderRoundingModeRTZFloat16;
        VkBool32                             shaderRoundingModeRTZFloat32;
        VkBool32                             shaderRoundingModeRTZFloat64;
        uint32_t                             maxUpdateAfterBindDescriptorsInAllPools;
        VkBool32                             shaderUniformBufferArrayNonUniformIndexingNative;
        VkBool32                             shaderSampledImageArrayNonUniformIndexingNative;
        VkBool32                             shaderStorageBufferArrayNonUniformIndexingNative;
        VkBool32                             shaderStorageImageArrayNonUniformIndexingNative;
        VkBool32                             shaderInputAttachmentArrayNonUniformIndexingNative;
        VkBool32                             robustBufferAccessUpdateAfterBind;
        VkBool32                             quadDivergentImplicitLod;
        uint32_t                             maxPerStageDescriptorUpdateAfterBindSamplers;
        uint32_t                             maxPerStageDescriptorUpdateAfterBindUniformBuffers;
        uint32_t                             maxPerStageDescriptorUpdateAfterBindStorageBuffers;
        uint32_t                             maxPerStageDescriptorUpdateAfterBindSampledImages;
        uint32_t                             maxPerStageDescriptorUpdateAfterBindStorageImages;
        uint32_t                             maxPerStageDescriptorUpdateAfterBindInputAttachments;
        uint32_t                             maxPerStageUpdateAfterBindResources;
        uint32_t                             maxDescriptorSetUpdateAfterBindSamplers;
        uint32_t                             maxDescriptorSetUpdateAfterBindUniformBuffers;
        uint32_t                             maxDescriptorSetUpdateAfterBindUniformBuffersDynamic;
        uint32_t                             maxDescriptorSetUpdateAfterBindStorageBuffers;
        uint32_t                             maxDescriptorSetUpdateAfterBindStorageBuffersDynamic;
        uint32_t                             maxDescriptorSetUpdateAfterBindSampledImages;
        uint32_t                             maxDescriptorSetUpdateAfterBindStorageImages;
        uint32_t                             maxDescriptorSetUpdateAfterBindInputAttachments;
        VkResolveModeFlags                   supportedDepthResolveModes;
        VkResolveModeFlags                   supportedStencilResolveModes;
        VkBool32                             independentResolveNone;
        VkBool32                             independentResolve;
        VkBool32                             filterMinmaxSingleComponentFormats;
        VkBool32                             filterMinmaxImageComponentMapping;
        uint64_t                             maxTimelineSemaphoreValueDifference;
        VkSampleCountFlags                   framebufferIntegerColorSampleCounts;
    } VkPhysicalDeviceVulkan12Properties;

- `driverID` is a unique identifier for the driver of the physical device.

- `driverName` is an array of `VK_MAX_DRIVER_NAME_SIZE_KHR` `char` containing a null-terminated UTF-8 string which is the name of the driver.

- `driverInfo` is an array of `VK_MAX_DRIVER_INFO_SIZE_KHR` `char` containing a null-terminated UTF-8 string with additional information about the driver.

- `conformanceVersion` is the version of the Vulkan conformance test this driver is conformant against (see VkConformanceVersion).

- `denormBehaviorIndependence` is a VkShaderFloatControlsIndependence value indicating whether, and how, denorm behavior can be set independently for different bit widths.

- `roundingModeIndependence` is a VkShaderFloatControlsIndependence value indicating whether, and how, rounding modes can be set independently for different bit widths.

- `shaderSignedZeroInfNanPreserveFloat16` is a boolean value indicating whether sign of a zero, Nans and \(\pm\infty\) can be preserved in 16-bit floating-point computations. It also indicates whether the `SignedZeroInfNanPreserve` execution mode can be used for 16-bit floating-point types.

- `shaderSignedZeroInfNanPreserveFloat32` is a boolean value indicating whether sign of a zero, Nans and \(\pm\infty\) can be preserved in 32-bit floating-point computations. It also indicates whether the `SignedZeroInfNanPreserve` execution mode can be used for 32-bit floating-point types.

- `shaderSignedZeroInfNanPreserveFloat64` is a boolean value indicating whether sign of a zero, Nans and \(\pm\infty\) can be preserved in 64-bit floating-point computations. It also indicates whether the `SignedZeroInfNanPreserve` execution mode can be used for 64-bit floating-point types.

- `shaderDenormPreserveFloat16` is a boolean value indicating whether denormals can be preserved in 16-bit floating-point computations. It also indicates whether the `DenormPreserve` execution mode can be used for 16-bit floating-point types.

- `shaderDenormPreserveFloat32` is a boolean value indicating whether denormals can be preserved in 32-bit floating-point computations. It also indicates whether the `DenormPreserve` execution mode can be used for 32-bit floating-point types.

- `shaderDenormPreserveFloat64` is a boolean value indicating whether denormals can be preserved in 64-bit floating-point computations. It also indicates whether the `DenormPreserve` execution mode can be used for 64-bit floating-point types.

- `shaderDenormFlushToZeroFloat16` is a boolean value indicating whether denormals can be flushed to zero in 16-bit floating-point computations. It also indicates whether the `DenormFlushToZero` execution mode can be used for 16-bit floating-point types.

- `shaderDenormFlushToZeroFloat32` is a boolean value indicating whether denormals can be flushed to zero in 32-bit floating-point computations. It also indicates whether the `DenormFlushToZero` execution mode can be used for 32-bit floating-point types.

- `shaderDenormFlushToZeroFloat64` is a boolean value indicating whether denormals can be flushed to zero in 64-bit floating-point computations. It also indicates whether the `DenormFlushToZero` execution mode can be used for 64-bit floating-point types.

- `shaderRoundingModeRTEFloat16` is a boolean value indicating whether an implementation supports the round-to-nearest-even rounding mode for 16-bit floating-point arithmetic and conversion instructions. It also indicates whether the `RoundingModeRTE` execution mode can be used for 16-bit floating-point types.

- `shaderRoundingModeRTEFloat32` is a boolean value indicating whether an implementation supports the round-to-nearest-even rounding mode for 32-bit floating-point arithmetic and conversion instructions. It also indicates whether the `RoundingModeRTE` execution mode can be used for 32-bit floating-point types.

- `shaderRoundingModeRTEFloat64` is a boolean value indicating whether an implementation supports the round-to-nearest-even rounding mode for 64-bit floating-point arithmetic and conversion instructions. It also indicates whether the `RoundingModeRTE` execution mode can be used for 64-bit floating-point types.

- `shaderRoundingModeRTZFloat16` is a boolean value indicating whether an implementation supports the round-towards-zero rounding mode for 16-bit floating-point arithmetic and conversion instructions. It also indicates whether the `RoundingModeRTZ` execution mode can be used for 16-bit floating-point types.

- `shaderRoundingModeRTZFloat32` is a boolean value indicating whether an implementation supports the round-towards-zero rounding mode for 32-bit floating-point arithmetic and conversion instructions. It also indicates whether the `RoundingModeRTZ` execution mode can be used for 32-bit floating-point types.

- `shaderRoundingModeRTZFloat64` is a boolean value indicating whether an implementation supports the round-towards-zero rounding mode for 64-bit floating-point arithmetic and conversion instructions. It also indicates whether the `RoundingModeRTZ` execution mode can be used for 64-bit floating-point types.

- `maxUpdateAfterBindDescriptorsInAllPools` is the maximum number of descriptors (summed over all descriptor types) that can be created across all pools that are created with the `VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT` bit set. Pool creation may fail when this limit is exceeded, or when the space this limit represents is unable to satisfy a pool creation due to fragmentation.

- `shaderUniformBufferArrayNonUniformIndexingNative` is a boolean value indicating whether uniform buffer descriptors natively support nonuniform indexing. If this is `VK_FALSE`, then a single dynamic instance of an instruction that nonuniformly indexes an array of uniform buffers may execute multiple times in order to access all the descriptors.

- `shaderSampledImageArrayNonUniformIndexingNative` is a boolean value indicating whether sampler and image descriptors natively support nonuniform indexing. If this is `VK_FALSE`, then a single dynamic instance of an instruction that nonuniformly indexes an array of samplers or images may execute multiple times in order to access all the descriptors.

- `shaderStorageBufferArrayNonUniformIndexingNative` is a boolean value indicating whether storage buffer descriptors natively support nonuniform indexing. If this is `VK_FALSE`, then a single dynamic instance of an instruction that nonuniformly indexes an array of storage buffers may execute multiple times in order to access all the descriptors.

- `shaderStorageImageArrayNonUniformIndexingNative` is a boolean value indicating whether storage image descriptors natively support nonuniform indexing. If this is `VK_FALSE`, then a single dynamic instance of an instruction that nonuniformly indexes an array of storage images may execute multiple times in order to access all the descriptors.

- `shaderInputAttachmentArrayNonUniformIndexingNative` is a boolean value indicating whether input attachment descriptors natively support nonuniform indexing. If this is `VK_FALSE`, then a single dynamic instance of an instruction that nonuniformly indexes an array of input attachments may execute multiple times in order to access all the descriptors.

- `robustBufferAccessUpdateAfterBind` is a boolean value indicating whether `robustBufferAccess` can be enabled in a device simultaneously with `descriptorBindingUniformBufferUpdateAfterBind`, `descriptorBindingStorageBufferUpdateAfterBind`, `descriptorBindingUniformTexelBufferUpdateAfterBind`, and/or `descriptorBindingStorageTexelBufferUpdateAfterBind`. If this is `VK_FALSE`, then either `robustBufferAccess` must be disabled or all of these update-after-bind features must be disabled.

- `quadDivergentImplicitLod` is a boolean value indicating whether implicit level of detail calculations for image operations have well-defined results when the image and/or sampler objects used for the instruction are not uniform within a quad. See Derivative Image Operations.

- `maxPerStageDescriptorUpdateAfterBindSamplers` is similar to `maxPerStageDescriptorSamplers` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxPerStageDescriptorUpdateAfterBindUniformBuffers` is similar to `maxPerStageDescriptorUniformBuffers` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxPerStageDescriptorUpdateAfterBindStorageBuffers` is similar to `maxPerStageDescriptorStorageBuffers` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxPerStageDescriptorUpdateAfterBindSampledImages` is similar to `maxPerStageDescriptorSampledImages` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxPerStageDescriptorUpdateAfterBindStorageImages` is similar to `maxPerStageDescriptorStorageImages` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxPerStageDescriptorUpdateAfterBindInputAttachments` is similar to `maxPerStageDescriptorInputAttachments` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxPerStageUpdateAfterBindResources` is similar to `maxPerStageResources` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxDescriptorSetUpdateAfterBindSamplers` is similar to `maxDescriptorSetSamplers` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxDescriptorSetUpdateAfterBindUniformBuffers` is similar to `maxDescriptorSetUniformBuffers` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxDescriptorSetUpdateAfterBindUniformBuffersDynamic` is similar to `maxDescriptorSetUniformBuffersDynamic` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxDescriptorSetUpdateAfterBindStorageBuffers` is similar to `maxDescriptorSetStorageBuffers` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxDescriptorSetUpdateAfterBindStorageBuffersDynamic` is similar to `maxDescriptorSetStorageBuffersDynamic` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxDescriptorSetUpdateAfterBindSampledImages` is similar to `maxDescriptorSetSampledImages` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxDescriptorSetUpdateAfterBindStorageImages` is similar to `maxDescriptorSetStorageImages` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxDescriptorSetUpdateAfterBindInputAttachments` is similar to `maxDescriptorSetInputAttachments` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `supportedDepthResolveModes` is a bitmask of VkResolveModeFlagBits indicating the set of supported depth resolve modes. `VK_RESOLVE_MODE_SAMPLE_ZERO_BIT` must be included in the set but implementations may support additional modes.

- `supportedStencilResolveModes` is a bitmask of VkResolveModeFlagBits indicating the set of supported stencil resolve modes. `VK_RESOLVE_MODE_SAMPLE_ZERO_BIT` must be included in the set but implementations may support additional modes. `VK_RESOLVE_MODE_AVERAGE_BIT` must not be included in the set.

- `independentResolveNone` is `VK_TRUE` if the implementation supports setting the depth and stencil resolve modes to different values when one of those modes is `VK_RESOLVE_MODE_NONE`. Otherwise the implementation only supports setting both modes to the same value.

- `independentResolve` is `VK_TRUE` if the implementation supports all combinations of the supported depth and stencil resolve modes, including setting either depth or stencil resolve mode to `VK_RESOLVE_MODE_NONE`. An implementation that supports `independentResolve` must also support `independentResolveNone`.

- `filterMinmaxSingleComponentFormats` is a boolean value indicating whether a minimum set of required formats support min/max filtering.

- `filterMinmaxImageComponentMapping` is a boolean value indicating whether the implementation supports non-identity component mapping of the image when doing min/max filtering.

- `maxTimelineSemaphoreValueDifference` indicates the maximum difference allowed by the implementation between the current value of a timeline semaphore and any pending signal or wait operations.

- `framebufferIntegerColorSampleCounts` is a bitmask of VkSampleCountFlagBits indicating the color sample counts that are supported for all framebuffer color attachments with integer formats.

The members of `VkPhysicalDeviceVulkan12Properties` must have the same values as the corresponding members of VkPhysicalDeviceDriverProperties, VkPhysicalDeviceFloatControlsProperties, VkPhysicalDeviceDescriptorIndexingProperties, VkPhysicalDeviceDepthStencilResolveProperties, VkPhysicalDeviceSamplerFilterMinmaxProperties, and VkPhysicalDeviceTimelineSemaphoreProperties.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VULKAN_1_2_PROPERTIES`

- `driverID` must be a valid VkDriverId value

- `driverName` must be a null-terminated UTF-8 string whose length is less than or equal to VK_MAX_DRIVER_NAME_SIZE

- `driverInfo` must be a null-terminated UTF-8 string whose length is less than or equal to VK_MAX_DRIVER_INFO_SIZE

- `denormBehaviorIndependence` must be a valid VkShaderFloatControlsIndependence value

- `roundingModeIndependence` must be a valid VkShaderFloatControlsIndependence value

- `supportedDepthResolveModes` must be a valid combination of VkResolveModeFlagBits values

- `supportedDepthResolveModes` must not be `0`

- `supportedStencilResolveModes` must be a valid combination of VkResolveModeFlagBits values

- `supportedStencilResolveModes` must not be `0`

- `framebufferIntegerColorSampleCounts` must be a valid combination of VkSampleCountFlagBits values

To query the UUID and LUID of a device, add a VkPhysicalDeviceIDProperties structure to the `pNext` chain of the VkPhysicalDeviceProperties2 structure. The `VkPhysicalDeviceIDProperties` structure is defined as:

    typedef struct VkPhysicalDeviceIDProperties {
        VkStructureType    sType;
        void*              pNext;
        uint8_t            deviceUUID[VK_UUID_SIZE];
        uint8_t            driverUUID[VK_UUID_SIZE];
        uint8_t            deviceLUID[VK_LUID_SIZE];
        uint32_t           deviceNodeMask;
        VkBool32           deviceLUIDValid;
    } VkPhysicalDeviceIDProperties;

or the equivalent

    typedef VkPhysicalDeviceIDProperties VkPhysicalDeviceIDPropertiesKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `deviceUUID` is an array of `VK_UUID_SIZE` `uint8_t` values representing a universally unique identifier for the device.

- `driverUUID` is an array of `VK_UUID_SIZE` `uint8_t` values representing a universally unique identifier for the driver build in use by the device.

- `deviceLUID` is an array of `VK_LUID_SIZE` `uint8_t` values representing a locally unique identifier for the device.

- `deviceNodeMask` is a `uint32_t` bitfield identifying the node within a linked device adapter corresponding to the device.

- `deviceLUIDValid` is a boolean value that will be `VK_TRUE` if `deviceLUID` contains a valid LUID and `deviceNodeMask` contains a valid node mask, and `VK_FALSE` if they do not.

`deviceUUID` must be immutable for a given device across instances, processes, driver APIs, driver versions, and system reboots.

Applications can compare the `driverUUID` value across instance and process boundaries, and can make similar queries in external APIs to determine whether they are capable of sharing memory objects and resources using them with the device.

`deviceUUID` and/or `driverUUID` must be used to determine whether a particular external object can be shared between driver components, where such a restriction exists as defined in the compatibility table for the particular object type:

- External memory handle types compatibility

- External semaphore handle types compatibility

- External fence handle types compatibility

If `deviceLUIDValid` is `VK_FALSE`, the values of `deviceLUID` and `deviceNodeMask` are undefined. If `deviceLUIDValid` is `VK_TRUE` and Vulkan is running on the Windows operating system, the contents of `deviceLUID` can be cast to an `LUID` object and must be equal to the locally unique identifier of a `IDXGIAdapter1` object that corresponds to `physicalDevice`. If `deviceLUIDValid` is `VK_TRUE`, `deviceNodeMask` must contain exactly one bit. If Vulkan is running on an operating system that supports the Direct3D 12 API and `physicalDevice` corresponds to an individual device in a linked device adapter, `deviceNodeMask` identifies the Direct3D 12 node corresponding to `physicalDevice`. Otherwise, `deviceNodeMask` must be `1`.

| Note Although they have identical descriptions, VkPhysicalDeviceIDProperties::`deviceUUID` may differ from VkPhysicalDeviceProperties2::`pipelineCacheUUID`. The former is intended to identify and correlate devices across API and driver boundaries, while the latter is used to identify a compatible device and driver combination to use when serializing and de-serializing pipeline state.

| Note While VkPhysicalDeviceIDProperties::`deviceUUID` is specified to remain consistent across driver versions and system reboots, it is not intended to be usable as a serializable persistent identifier for a device. It may change when a device is physically added to, removed from, or moved to a different connector in a system while that system is powered down. Further, there is no reasonable way to verify with conformance testing that a given device retains the same UUID in a given system across all driver versions supported in that system. While implementations should make every effort to report consistent device UUIDs across driver versions, applications should avoid relying on the persistence of this value for uses other than identifying compatible devices for external object sharing purposes.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_ID_PROPERTIES`

To query the properties of the driver corresponding to a physical device, add a VkPhysicalDeviceDriverProperties structure to the `pNext` chain of the VkPhysicalDeviceProperties2 structure. The `VkPhysicalDeviceDriverProperties` structure is defined as:

    typedef struct VkPhysicalDeviceDriverProperties {
        VkStructureType         sType;
        void*                   pNext;
        VkDriverId              driverID;
        char                    driverName[VK_MAX_DRIVER_NAME_SIZE];
        char                    driverInfo[VK_MAX_DRIVER_INFO_SIZE];
        VkConformanceVersion    conformanceVersion;
    } VkPhysicalDeviceDriverProperties;

or the equivalent

    typedef VkPhysicalDeviceDriverProperties VkPhysicalDeviceDriverPropertiesKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension specific structure.

- `driverID` is a unique identifier for the driver of the physical device.

- `driverName` is an array of `VK_MAX_DRIVER_NAME_SIZE_KHR` `char` containing a null-terminated UTF-8 string which is the name of the driver.

- `driverInfo` is an array of `VK_MAX_DRIVER_INFO_SIZE_KHR` `char` containing a null-terminated UTF-8 string with additional information about the driver.

- `conformanceVersion` is the version of the Vulkan conformance test this driver is conformant against (see VkConformanceVersion).

`driverID` must be immutable for a given driver across instances, processes, driver versions, and system reboots.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DRIVER_PROPERTIES`

Khronos driver IDs which may be returned in VkPhysicalDeviceDriverProperties::`driverID` are:

    typedef enum VkDriverId {
        VK_DRIVER_ID_AMD_PROPRIETARY = 1,
        VK_DRIVER_ID_AMD_OPEN_SOURCE = 2,
        VK_DRIVER_ID_MESA_RADV = 3,
        VK_DRIVER_ID_NVIDIA_PROPRIETARY = 4,
        VK_DRIVER_ID_INTEL_PROPRIETARY_WINDOWS = 5,
        VK_DRIVER_ID_INTEL_OPEN_SOURCE_MESA = 6,
        VK_DRIVER_ID_IMAGINATION_PROPRIETARY = 7,
        VK_DRIVER_ID_QUALCOMM_PROPRIETARY = 8,
        VK_DRIVER_ID_ARM_PROPRIETARY = 9,
        VK_DRIVER_ID_GOOGLE_SWIFTSHADER = 10,
        VK_DRIVER_ID_GGP_PROPRIETARY = 11,
        VK_DRIVER_ID_BROADCOM_PROPRIETARY = 12,
        VK_DRIVER_ID_AMD_PROPRIETARY_KHR = VK_DRIVER_ID_AMD_PROPRIETARY,
        VK_DRIVER_ID_AMD_OPEN_SOURCE_KHR = VK_DRIVER_ID_AMD_OPEN_SOURCE,
        VK_DRIVER_ID_MESA_RADV_KHR = VK_DRIVER_ID_MESA_RADV,
        VK_DRIVER_ID_NVIDIA_PROPRIETARY_KHR = VK_DRIVER_ID_NVIDIA_PROPRIETARY,
        VK_DRIVER_ID_INTEL_PROPRIETARY_WINDOWS_KHR = VK_DRIVER_ID_INTEL_PROPRIETARY_WINDOWS,
        VK_DRIVER_ID_INTEL_OPEN_SOURCE_MESA_KHR = VK_DRIVER_ID_INTEL_OPEN_SOURCE_MESA,
        VK_DRIVER_ID_IMAGINATION_PROPRIETARY_KHR = VK_DRIVER_ID_IMAGINATION_PROPRIETARY,
        VK_DRIVER_ID_QUALCOMM_PROPRIETARY_KHR = VK_DRIVER_ID_QUALCOMM_PROPRIETARY,
        VK_DRIVER_ID_ARM_PROPRIETARY_KHR = VK_DRIVER_ID_ARM_PROPRIETARY,
        VK_DRIVER_ID_GOOGLE_SWIFTSHADER_KHR = VK_DRIVER_ID_GOOGLE_SWIFTSHADER,
        VK_DRIVER_ID_GGP_PROPRIETARY_KHR = VK_DRIVER_ID_GGP_PROPRIETARY,
        VK_DRIVER_ID_BROADCOM_PROPRIETARY_KHR = VK_DRIVER_ID_BROADCOM_PROPRIETARY,
        VK_DRIVER_ID_MAX_ENUM = 0x7FFFFFFF
    } VkDriverId;

or the equivalent

    typedef VkDriverId VkDriverIdKHR;

| Note Khronos driver IDs may be allocated by vendors at any time. There may be multiple driver IDs for the same vendor, representing different drivers (for e.g. different platforms, proprietary or open source, etc.). Only the latest canonical versions of this Specification, of the corresponding `vk.xml` API Registry, and of the corresponding `vulkan_core.h` header file must contain all reserved Khronos driver IDs. Only driver IDs registered with Khronos are given symbolic names. There may be unregistered driver IDs returned.

The conformance test suite version an implementation is compliant with is described with the `VkConformanceVersion` structure:

    typedef struct VkConformanceVersion {
        uint8_t    major;
        uint8_t    minor;
        uint8_t    subminor;
        uint8_t    patch;
    } VkConformanceVersion;

or the equivalent

    typedef VkConformanceVersion VkConformanceVersionKHR;

- `major` is the major version number of the conformance test suite.

- `minor` is the minor version number of the conformance test suite.

- `subminor` is the subminor version number of the conformance test suite.

- `patch` is the patch version number of the conformance test suite.

To query the PCI bus information of a physical device, add a VkPhysicalDevicePCIBusInfoPropertiesEXT structure to the `pNext` chain of the VkPhysicalDeviceProperties2 structure. The `VkPhysicalDevicePCIBusInfoPropertiesEXT` structure is defined as:

    typedef struct VkPhysicalDevicePCIBusInfoPropertiesEXT {
        VkStructureType    sType;
        void*              pNext;
        uint32_t           pciDomain;
        uint32_t           pciBus;
        uint32_t           pciDevice;
        uint32_t           pciFunction;
    } VkPhysicalDevicePCIBusInfoPropertiesEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `pciDomain` is the PCI bus domain.

- `pciBus` is the PCI bus identifier.

- `pciDevice` is the PCI device identifier.

- `pciFunction` is the PCI device function identifier.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PCI_BUS_INFO_PROPERTIES_EXT`

To query properties of queues available on a physical device, call:

    void vkGetPhysicalDeviceQueueFamilyProperties(
        VkPhysicalDevice                            physicalDevice,
        uint32_t*                                   pQueueFamilyPropertyCount,
        VkQueueFamilyProperties*                    pQueueFamilyProperties);

- `physicalDevice` is the handle to the physical device whose properties will be queried.

- `pQueueFamilyPropertyCount` is a pointer to an integer related to the number of queue families available or queried, as described below.

- `pQueueFamilyProperties` is either `NULL` or a pointer to an array of VkQueueFamilyProperties structures.

If `pQueueFamilyProperties` is `NULL`, then the number of queue families available is returned in `pQueueFamilyPropertyCount`. Implementations must support at least one queue family. Otherwise, `pQueueFamilyPropertyCount` must point to a variable set by the user to the number of elements in the `pQueueFamilyProperties` array, and on return the variable is overwritten with the number of structures actually written to `pQueueFamilyProperties`. If `pQueueFamilyPropertyCount` is less than the number of queue families available, at most `pQueueFamilyPropertyCount` structures will be written.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pQueueFamilyPropertyCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pQueueFamilyPropertyCount` is not `0`, and `pQueueFamilyProperties` is not `NULL`, `pQueueFamilyProperties` must be a valid pointer to an array of `pQueueFamilyPropertyCount` VkQueueFamilyProperties structures

The `VkQueueFamilyProperties` structure is defined as:

    typedef struct VkQueueFamilyProperties {
        VkQueueFlags    queueFlags;
        uint32_t        queueCount;
        uint32_t        timestampValidBits;
        VkExtent3D      minImageTransferGranularity;
    } VkQueueFamilyProperties;

- `queueFlags` is a bitmask of VkQueueFlagBits indicating capabilities of the queues in this queue family.

- `queueCount` is the unsigned integer count of queues in this queue family. Each queue family must support at least one queue.

- `timestampValidBits` is the unsigned integer count of meaningful bits in the timestamps written via `vkCmdWriteTimestamp`. The valid range for the count is 36..64 bits, or a value of 0, indicating no support for timestamps. Bits outside the valid range are guaranteed to be zeros.

- `minImageTransferGranularity` is the minimum granularity supported for image transfer operations on the queues in this queue family.

The value returned in `minImageTransferGranularity` has a unit of compressed texel blocks for images having a block-compressed format, and a unit of texels otherwise.

Possible values of `minImageTransferGranularity` are:

- (0,0,0) which indicates that only whole mip levels must be transferred using the image transfer operations on the corresponding queues. In this case, the following restrictions apply to all offset and extent parameters of image transfer operations:

  - The `x`, `y`, and `z` members of a VkOffset3D parameter must always be zero.

  - The `width`, `height`, and `depth` members of a VkExtent3D parameter must always match the width, height, and depth of the image subresource corresponding to the parameter, respectively.

- (Ax, Ay, Az) where Ax, Ay, and Az are all integer powers of two. In this case the following restrictions apply to all image transfer operations:

  - `x`, `y`, and `z` of a VkOffset3D parameter must be integer multiples of Ax, Ay, and Az, respectively.

  - `width` of a VkExtent3D parameter must be an integer multiple of Ax, or else `x` + `width` must equal the width of the image subresource corresponding to the parameter.

  - `height` of a VkExtent3D parameter must be an integer multiple of Ay, or else `y` + `height` must equal the height of the image subresource corresponding to the parameter.

  - `depth` of a VkExtent3D parameter must be an integer multiple of Az, or else `z` + `depth` must equal the depth of the image subresource corresponding to the parameter.

  - If the format of the image corresponding to the parameters is one of the block-compressed formats then for the purposes of the above calculations the granularity must be scaled up by the compressed texel block dimensions.

Queues supporting graphics and/or compute operations must report (1,1,1) in `minImageTransferGranularity`, meaning that there are no additional restrictions on the granularity of image transfer operations for these queues. Other queues supporting image transfer operations are only required to support whole mip level transfers, thus `minImageTransferGranularity` for queues belonging to such queue families may be (0,0,0).

The Device Memory section describes memory properties queried from the physical device.

For physical device feature queries see the Features chapter.

Bits which may be set in VkQueueFamilyProperties::`queueFlags` indicating capabilities of queues in a queue family are:

    typedef enum VkQueueFlagBits {
        VK_QUEUE_GRAPHICS_BIT = 0x00000001,
        VK_QUEUE_COMPUTE_BIT = 0x00000002,
        VK_QUEUE_TRANSFER_BIT = 0x00000004,
        VK_QUEUE_SPARSE_BINDING_BIT = 0x00000008,
        VK_QUEUE_PROTECTED_BIT = 0x00000010,
        VK_QUEUE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkQueueFlagBits;

- `VK_QUEUE_GRAPHICS_BIT` specifies that queues in this queue family support graphics operations.

- `VK_QUEUE_COMPUTE_BIT` specifies that queues in this queue family support compute operations.

- `VK_QUEUE_TRANSFER_BIT` specifies that queues in this queue family support transfer operations.

- `VK_QUEUE_SPARSE_BINDING_BIT` specifies that queues in this queue family support sparse memory management operations (see Sparse Resources). If any of the sparse resource features are enabled, then at least one queue family must support this bit.

- if `VK_QUEUE_PROTECTED_BIT` is set, then the queues in this queue family support the `VK_DEVICE_QUEUE_CREATE_PROTECTED_BIT` bit. (see Protected Memory). If the protected memory physical device feature is supported, then at least one queue family of at least one physical device exposed by the implementation must support this bit.

If an implementation exposes any queue family that supports graphics operations, at least one queue family of at least one physical device exposed by the implementation must support both graphics and compute operations.

Furthermore, if the protected memory physical device feature is supported, then at least one queue family of at least one physical device exposed by the implementation must support graphics operations, compute operations, and protected memory operations.

| Note All commands that are allowed on a queue that supports transfer operations are also allowed on a queue that supports either graphics or compute operations. Thus, if the capabilities of a queue family include `VK_QUEUE_GRAPHICS_BIT` or `VK_QUEUE_COMPUTE_BIT`, then reporting the `VK_QUEUE_TRANSFER_BIT` capability separately for that queue family is optional.

For further details see Queues.

    typedef VkFlags VkQueueFlags;

`VkQueueFlags` is a bitmask type for setting a mask of zero or more VkQueueFlagBits.

To query properties of queues available on a physical device, call:

    void vkGetPhysicalDeviceQueueFamilyProperties2(
        VkPhysicalDevice                            physicalDevice,
        uint32_t*                                   pQueueFamilyPropertyCount,
        VkQueueFamilyProperties2*                   pQueueFamilyProperties);

or the equivalent command

    void vkGetPhysicalDeviceQueueFamilyProperties2KHR(
        VkPhysicalDevice                            physicalDevice,
        uint32_t*                                   pQueueFamilyPropertyCount,
        VkQueueFamilyProperties2*                   pQueueFamilyProperties);

- `physicalDevice` is the handle to the physical device whose properties will be queried.

- `pQueueFamilyPropertyCount` is a pointer to an integer related to the number of queue families available or queried, as described in vkGetPhysicalDeviceQueueFamilyProperties.

- `pQueueFamilyProperties` is either `NULL` or a pointer to an array of VkQueueFamilyProperties2 structures.

`vkGetPhysicalDeviceQueueFamilyProperties2` behaves similarly to vkGetPhysicalDeviceQueueFamilyProperties, with the ability to return extended information in a `pNext` chain of output structures.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pQueueFamilyPropertyCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pQueueFamilyPropertyCount` is not `0`, and `pQueueFamilyProperties` is not `NULL`, `pQueueFamilyProperties` must be a valid pointer to an array of `pQueueFamilyPropertyCount` VkQueueFamilyProperties2 structures

The `VkQueueFamilyProperties2` structure is defined as:

    typedef struct VkQueueFamilyProperties2 {
        VkStructureType            sType;
        void*                      pNext;
        VkQueueFamilyProperties    queueFamilyProperties;
    } VkQueueFamilyProperties2;

or the equivalent

    typedef VkQueueFamilyProperties2 VkQueueFamilyProperties2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `queueFamilyProperties` is a VkQueueFamilyProperties structure which is populated with the same values as in vkGetPhysicalDeviceQueueFamilyProperties.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_QUEUE_FAMILY_PROPERTIES_2`

- `pNext` must be `NULL` or a pointer to a valid instance of VkQueueFamilyCheckpointPropertiesNV

- The `sType` value of each struct in the `pNext` chain must be unique

Additional queue family information can be queried by setting VkQueueFamilyProperties2::`pNext` to point to a VkQueueFamilyCheckpointPropertiesNV structure.

The VkQueueFamilyCheckpointPropertiesNV structure is defined as:

    typedef struct VkQueueFamilyCheckpointPropertiesNV {
        VkStructureType         sType;
        void*                   pNext;
        VkPipelineStageFlags    checkpointExecutionStageMask;
    } VkQueueFamilyCheckpointPropertiesNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `checkpointExecutionStageMask` is a mask indicating which pipeline stages the implementation can execute checkpoint markers in.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_QUEUE_FAMILY_CHECKPOINT_PROPERTIES_NV`

To enumerate the performance query counters available on a queue family of a physical device, call:

    VkResult vkEnumeratePhysicalDeviceQueueFamilyPerformanceQueryCountersKHR(
        VkPhysicalDevice                            physicalDevice,
        uint32_t                                    queueFamilyIndex,
        uint32_t*                                   pCounterCount,
        VkPerformanceCounterKHR*                    pCounters,
        VkPerformanceCounterDescriptionKHR*         pCounterDescriptions);

- `physicalDevice` is the handle to the physical device whose queue family performance query counter properties will be queried.

- `queueFamilyIndex` is the index into the queue family of the physical device we want to get properties for.

- `pCounterCount` is a pointer to an integer related to the number of counters available or queried, as described below.

- `pCounters` is either `NULL` or a pointer to an array of VkPerformanceCounterKHR structures.

- `pCounterDescriptions` is either `NULL` or a pointer to an array of VkPerformanceCounterDescriptionKHR structures.

If `pCounters` is `NULL` and `pCounterDescriptions` is `NULL`, then the number of counters available is returned in `pCounterCount`. Otherwise, `pCounterCount` must point to a variable set by the user to the number of elements in the `pCounters`, `pCounterDescriptions`, or both arrays and on return the variable is overwritten with the number of structures actually written out. If `pCounterCount` is less than the number of counters available, at most `pCounterCount` structures will be written and `VK_INCOMPLETE` will be returned instead of `VK_SUCCESS`.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pCounterCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pCounterCount` is not `0`, and `pCounters` is not `NULL`, `pCounters` must be a valid pointer to an array of `pCounterCount` VkPerformanceCounterKHR structures

- If the value referenced by `pCounterCount` is not `0`, and `pCounterDescriptions` is not `NULL`, `pCounterDescriptions` must be a valid pointer to an array of `pCounterCount` VkPerformanceCounterDescriptionKHR structures

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_INITIALIZATION_FAILED`

The `VkPerformanceCounterKHR` structure is defined as:

    typedef struct VkPerformanceCounterKHR {
        VkStructureType                   sType;
        const void*                       pNext;
        VkPerformanceCounterUnitKHR       unit;
        VkPerformanceCounterScopeKHR      scope;
        VkPerformanceCounterStorageKHR    storage;
        uint8_t                           uuid[VK_UUID_SIZE];
    } VkPerformanceCounterKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `unit` is a VkPerformanceCounterUnitKHR specifying the unit that the counter data will record.

- `scope` is a VkPerformanceCounterScopeKHR specifying the scope that the counter belongs to.

- `storage` is a VkPerformanceCounterStorageKHR specifying the storage type that the counter’s data uses.

- `uuid` is an array of size `VK_UUID_SIZE`, containing 8-bit values that represent a universally unique identifier for the counter of the physical device.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PERFORMANCE_COUNTER_KHR`

- `pNext` must be `NULL`

Performance counters have an associated unit. This unit describes how to interpret the performance counter result.

The performance counter unit types which may be returned in VkPerformanceCounterKHR::`unit` are:

    typedef enum VkPerformanceCounterUnitKHR {
        VK_PERFORMANCE_COUNTER_UNIT_GENERIC_KHR = 0,
        VK_PERFORMANCE_COUNTER_UNIT_PERCENTAGE_KHR = 1,
        VK_PERFORMANCE_COUNTER_UNIT_NANOSECONDS_KHR = 2,
        VK_PERFORMANCE_COUNTER_UNIT_BYTES_KHR = 3,
        VK_PERFORMANCE_COUNTER_UNIT_BYTES_PER_SECOND_KHR = 4,
        VK_PERFORMANCE_COUNTER_UNIT_KELVIN_KHR = 5,
        VK_PERFORMANCE_COUNTER_UNIT_WATTS_KHR = 6,
        VK_PERFORMANCE_COUNTER_UNIT_VOLTS_KHR = 7,
        VK_PERFORMANCE_COUNTER_UNIT_AMPS_KHR = 8,
        VK_PERFORMANCE_COUNTER_UNIT_HERTZ_KHR = 9,
        VK_PERFORMANCE_COUNTER_UNIT_CYCLES_KHR = 10,
        VK_PERFORMANCE_COUNTER_UNIT_MAX_ENUM_KHR = 0x7FFFFFFF
    } VkPerformanceCounterUnitKHR;

- `VK_PERFORMANCE_COUNTER_UNIT_GENERIC_KHR` - the performance counter unit is a generic data point.

- `VK_PERFORMANCE_COUNTER_UNIT_PERCENTAGE_KHR` - the performance counter unit is a percentage (%).

- `VK_PERFORMANCE_COUNTER_UNIT_NANOSECONDS_KHR` - the performance counter unit is a value of nanoseconds (ns).

- `VK_PERFORMANCE_COUNTER_UNIT_BYTES_KHR` - the performance counter unit is a value of bytes.

- `VK_PERFORMANCE_COUNTER_UNIT_BYTES_PER_SECOND_KHR` - the performance counter unit is a value of bytes/s.

- `VK_PERFORMANCE_COUNTER_UNIT_KELVIN_KHR` - the performance counter unit is a temperature reported in Kelvin.

- `VK_PERFORMANCE_COUNTER_UNIT_WATTS_KHR` - the performance counter unit is a value of watts (W).

- `VK_PERFORMANCE_COUNTER_UNIT_VOLTS_KHR` - the performance counter unit is a value of volts (V).

- `VK_PERFORMANCE_COUNTER_UNIT_AMPS_KHR` - the performance counter unit is a value of amps (A).

- `VK_PERFORMANCE_COUNTER_UNIT_HERTZ_KHR` - the performance counter unit is a value of hertz (Hz).

- `VK_PERFORMANCE_COUNTER_UNIT_CYCLES_KHR` - the performance counter unit is a value of cycles.

Performance counters have an associated scope. This scope describes the granularity of a performance counter.

The performance counter scope types which may be returned in VkPerformanceCounterKHR::`scope` are:

    typedef enum VkPerformanceCounterScopeKHR {
        VK_PERFORMANCE_COUNTER_SCOPE_COMMAND_BUFFER_KHR = 0,
        VK_PERFORMANCE_COUNTER_SCOPE_RENDER_PASS_KHR = 1,
        VK_PERFORMANCE_COUNTER_SCOPE_COMMAND_KHR = 2,
        VK_QUERY_SCOPE_COMMAND_BUFFER_KHR = VK_PERFORMANCE_COUNTER_SCOPE_COMMAND_BUFFER_KHR,
        VK_QUERY_SCOPE_RENDER_PASS_KHR = VK_PERFORMANCE_COUNTER_SCOPE_RENDER_PASS_KHR,
        VK_QUERY_SCOPE_COMMAND_KHR = VK_PERFORMANCE_COUNTER_SCOPE_COMMAND_KHR,
        VK_PERFORMANCE_COUNTER_SCOPE_MAX_ENUM_KHR = 0x7FFFFFFF
    } VkPerformanceCounterScopeKHR;

- `VK_PERFORMANCE_COUNTER_SCOPE_COMMAND_BUFFER_KHR` - the performance counter scope is a single complete command buffer.

- `VK_PERFORMANCE_COUNTER_SCOPE_RENDER_PASS_KHR` - the performance counter scope is zero or more complete render passes. The performance query containing the performance counter must begin and end outside a render pass instance.

- `VK_PERFORMANCE_COUNTER_SCOPE_COMMAND_KHR` - the performance counter scope is zero or more commands.

Performance counters have an associated storage. This storage describes the payload of a counter result.

The performance counter storage types which may be returned in VkPerformanceCounterKHR::`storage` are:

    typedef enum VkPerformanceCounterStorageKHR {
        VK_PERFORMANCE_COUNTER_STORAGE_INT32_KHR = 0,
        VK_PERFORMANCE_COUNTER_STORAGE_INT64_KHR = 1,
        VK_PERFORMANCE_COUNTER_STORAGE_UINT32_KHR = 2,
        VK_PERFORMANCE_COUNTER_STORAGE_UINT64_KHR = 3,
        VK_PERFORMANCE_COUNTER_STORAGE_FLOAT32_KHR = 4,
        VK_PERFORMANCE_COUNTER_STORAGE_FLOAT64_KHR = 5,
        VK_PERFORMANCE_COUNTER_STORAGE_MAX_ENUM_KHR = 0x7FFFFFFF
    } VkPerformanceCounterStorageKHR;

- `VK_PERFORMANCE_COUNTER_STORAGE_INT32_KHR` - the performance counter storage is a 32-bit signed integer.

- `VK_PERFORMANCE_COUNTER_STORAGE_INT64_KHR` - the performance counter storage is a 64-bit signed integer.

- `VK_PERFORMANCE_COUNTER_STORAGE_UINT32_KHR` - the performance counter storage is a 32-bit unsigned integer.

- `VK_PERFORMANCE_COUNTER_STORAGE_UINT64_KHR` - the performance counter storage is a 64-bit unsigned integer.

- `VK_PERFORMANCE_COUNTER_STORAGE_FLOAT32_KHR` - the performance counter storage is a 32-bit floating-point.

- `VK_PERFORMANCE_COUNTER_STORAGE_FLOAT64_KHR` - the performance counter storage is a 64-bit floating-point.

The `VkPerformanceCounterDescriptionKHR` structure is defined as:

    typedef struct VkPerformanceCounterDescriptionKHR {
        VkStructureType                            sType;
        const void*                                pNext;
        VkPerformanceCounterDescriptionFlagsKHR    flags;
        char                                       name[VK_MAX_DESCRIPTION_SIZE];
        char                                       category[VK_MAX_DESCRIPTION_SIZE];
        char                                       description[VK_MAX_DESCRIPTION_SIZE];
    } VkPerformanceCounterDescriptionKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkPerformanceCounterDescriptionFlagBitsKHR indicating the usage behavior for the counter.

- `name` is an array of size `VK_MAX_DESCRIPTION_SIZE`, containing a null-terminated UTF-8 string specifying the name of the counter.

- `category` is an array of size `VK_MAX_DESCRIPTION_SIZE`, containing a null-terminated UTF-8 string specifying the category of the counter.

- `description` is an array of size `VK_MAX_DESCRIPTION_SIZE`, containing a null-terminated UTF-8 string specifying the description of the counter.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PERFORMANCE_COUNTER_DESCRIPTION_KHR`

- `pNext` must be `NULL`

Bits which can be set in VkPerformanceCounterDescriptionKHR::`flags` to specify usage behavior for a command pool are:

    typedef enum VkPerformanceCounterDescriptionFlagBitsKHR {
        VK_PERFORMANCE_COUNTER_DESCRIPTION_PERFORMANCE_IMPACTING_KHR = 0x00000001,
        VK_PERFORMANCE_COUNTER_DESCRIPTION_CONCURRENTLY_IMPACTED_KHR = 0x00000002,
        VK_PERFORMANCE_COUNTER_DESCRIPTION_FLAG_BITS_MAX_ENUM_KHR = 0x7FFFFFFF
    } VkPerformanceCounterDescriptionFlagBitsKHR;

- `VK_PERFORMANCE_COUNTER_DESCRIPTION_PERFORMANCE_IMPACTING_KHR` specifies that recording the counter may have a noticeable performance impact.

- `VK_PERFORMANCE_COUNTER_DESCRIPTION_CONCURRENTLY_IMPACTED_KHR` specifies that concurrently recording the counter while other submitted command buffers are running may impact the accuracy of the recording.

    typedef VkFlags VkPerformanceCounterDescriptionFlagsKHR;

VkPerformanceCounterDescriptionFlagsKHR is a bitmask type for setting a mask of zero or more VkPerformanceCounterDescriptionFlagBitsKHR.

### 4.2. Devices

Device objects represent logical connections to physical devices. Each device exposes a number of queue families each having one or more queues. All queues in a queue family support the same operations.

As described in Physical Devices, a Vulkan application will first query for all physical devices in a system. Each physical device can then be queried for its capabilities, including its queue and queue family properties. Once an acceptable physical device is identified, an application will create a corresponding logical device. An application must create a separate logical device for each physical device it will use. The created logical device is then the primary interface to the physical device.

How to enumerate the physical devices in a system and query those physical devices for their queue family properties is described in the Physical Device Enumeration section above.

A single logical device can also be created from multiple physical devices, if those physical devices belong to the same device group. A device group is a set of physical devices that support accessing each other’s memory and recording a single command buffer that can be executed on all the physical devices. Device groups are enumerated by calling vkEnumeratePhysicalDeviceGroups, and a logical device is created from a subset of the physical devices in a device group by passing the physical devices through VkDeviceGroupDeviceCreateInfo. For two physical devices to be in the same device group, they must support identical extensions, features, and properties.

| Note Physical devices in the same device group must be so similar because there are no rules for how different features/properties would interact. They must return the same values for nearly every invariant `vkGetPhysicalDevice*` feature, property, capability, etc., but could potentially differ for certain queries based on things like having a different display connected, or different compositor, etc.. The specification does not attempt to enumerate which state is in each category, because such a list would quickly become out of date.

To retrieve a list of the device groups present in the system, call:

    VkResult vkEnumeratePhysicalDeviceGroups(
        VkInstance                                  instance,
        uint32_t*                                   pPhysicalDeviceGroupCount,
        VkPhysicalDeviceGroupProperties*            pPhysicalDeviceGroupProperties);

or the equivalent command

    VkResult vkEnumeratePhysicalDeviceGroupsKHR(
        VkInstance                                  instance,
        uint32_t*                                   pPhysicalDeviceGroupCount,
        VkPhysicalDeviceGroupProperties*            pPhysicalDeviceGroupProperties);

- `instance` is a handle to a Vulkan instance previously created with vkCreateInstance.

- `pPhysicalDeviceGroupCount` is a pointer to an integer related to the number of device groups available or queried, as described below.

- `pPhysicalDeviceGroupProperties` is either `NULL` or a pointer to an array of VkPhysicalDeviceGroupProperties structures.

If `pPhysicalDeviceGroupProperties` is `NULL`, then the number of device groups available is returned in `pPhysicalDeviceGroupCount`. Otherwise, `pPhysicalDeviceGroupCount` must point to a variable set by the user to the number of elements in the `pPhysicalDeviceGroupProperties` array, and on return the variable is overwritten with the number of structures actually written to `pPhysicalDeviceGroupProperties`. If `pPhysicalDeviceGroupCount` is less than the number of device groups available, at most `pPhysicalDeviceGroupCount` structures will be written. If `pPhysicalDeviceGroupCount` is smaller than the number of device groups available, `VK_INCOMPLETE` will be returned instead of `VK_SUCCESS`, to indicate that not all the available device groups were returned.

Every physical device must be in exactly one device group.

Valid Usage (Implicit)

- `instance` must be a valid VkInstance handle

- `pPhysicalDeviceGroupCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pPhysicalDeviceGroupCount` is not `0`, and `pPhysicalDeviceGroupProperties` is not `NULL`, `pPhysicalDeviceGroupProperties` must be a valid pointer to an array of `pPhysicalDeviceGroupCount` VkPhysicalDeviceGroupProperties structures

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_INITIALIZATION_FAILED`

The `VkPhysicalDeviceGroupProperties` structure is defined as:

    typedef struct VkPhysicalDeviceGroupProperties {
        VkStructureType     sType;
        void*               pNext;
        uint32_t            physicalDeviceCount;
        VkPhysicalDevice    physicalDevices[VK_MAX_DEVICE_GROUP_SIZE];
        VkBool32            subsetAllocation;
    } VkPhysicalDeviceGroupProperties;

or the equivalent

    typedef VkPhysicalDeviceGroupProperties VkPhysicalDeviceGroupPropertiesKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `physicalDeviceCount` is the number of physical devices in the group.

- `physicalDevices` is an array of `VK_MAX_DEVICE_GROUP_SIZE` VkPhysicalDevice handles representing all physical devices in the group. The first `physicalDeviceCount` elements of the array will be valid.

- `subsetAllocation` specifies whether logical devices created from the group support allocating device memory on a subset of devices, via the `deviceMask` member of the VkMemoryAllocateFlagsInfo. If this is `VK_FALSE`, then all device memory allocations are made across all physical devices in the group. If `physicalDeviceCount` is `1`, then `subsetAllocation` must be `VK_FALSE`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_GROUP_PROPERTIES`

- `pNext` must be `NULL`

#### 4.2.1. Device Creation

Logical devices are represented by `VkDevice` handles:

    VK_DEFINE_HANDLE(VkDevice)

A logical device is created as a connection to a physical device. To create a logical device, call:

    VkResult vkCreateDevice(
        VkPhysicalDevice                            physicalDevice,
        const VkDeviceCreateInfo*                   pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkDevice*                                   pDevice);

- `physicalDevice` must be one of the device handles returned from a call to `vkEnumeratePhysicalDevices` (see Physical Device Enumeration).

- `pCreateInfo` is a pointer to a VkDeviceCreateInfo structure containing information about how to create the device.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pDevice` is a pointer to a handle in which the created VkDevice is returned.

`vkCreateDevice` verifies that extensions and features requested in the `ppEnabledExtensionNames` and `pEnabledFeatures` members of `pCreateInfo`, respectively, are supported by the implementation. If any requested extension is not supported, `vkCreateDevice` must return `VK_ERROR_EXTENSION_NOT_PRESENT`. If any requested feature is not supported, `vkCreateDevice` must return `VK_ERROR_FEATURE_NOT_PRESENT`. Support for extensions can be checked before creating a device by querying vkEnumerateDeviceExtensionProperties. Support for features can similarly be checked by querying vkGetPhysicalDeviceFeatures.

After verifying and enabling the extensions the `VkDevice` object is created and returned to the application. If a requested extension is only supported by a layer, both the layer and the extension need to be specified at `vkCreateInstance` time for the creation to succeed.

Multiple logical devices can be created from the same physical device. Logical device creation may fail due to lack of device-specific resources (in addition to the other errors). If that occurs, `vkCreateDevice` will return `VK_ERROR_TOO_MANY_OBJECTS`.

Valid Usage

- All required extensions for each extension in the VkDeviceCreateInfo::`ppEnabledExtensionNames` list must also be present in that list.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkDeviceCreateInfo structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pDevice` must be a valid pointer to a VkDevice handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_INITIALIZATION_FAILED`

  - `VK_ERROR_EXTENSION_NOT_PRESENT`

  - `VK_ERROR_FEATURE_NOT_PRESENT`

  - `VK_ERROR_TOO_MANY_OBJECTS`

  - `VK_ERROR_DEVICE_LOST`

The `VkDeviceCreateInfo` structure is defined as:

    typedef struct VkDeviceCreateInfo {
        VkStructureType                    sType;
        const void*                        pNext;
        VkDeviceCreateFlags                flags;
        uint32_t                           queueCreateInfoCount;
        const VkDeviceQueueCreateInfo*     pQueueCreateInfos;
        uint32_t                           enabledLayerCount;
        const char* const*                 ppEnabledLayerNames;
        uint32_t                           enabledExtensionCount;
        const char* const*                 ppEnabledExtensionNames;
        const VkPhysicalDeviceFeatures*    pEnabledFeatures;
    } VkDeviceCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `queueCreateInfoCount` is the unsigned integer size of the `pQueueCreateInfos` array. Refer to the Queue Creation section below for further details.

- `pQueueCreateInfos` is a pointer to an array of VkDeviceQueueCreateInfo structures describing the queues that are requested to be created along with the logical device. Refer to the Queue Creation section below for further details.

- `enabledLayerCount` is deprecated and ignored.

- `ppEnabledLayerNames` is deprecated and ignored. See Device Layer Deprecation.

- `enabledExtensionCount` is the number of device extensions to enable.

- `ppEnabledExtensionNames` is a pointer to an array of `enabledExtensionCount` null-terminated UTF-8 strings containing the names of extensions to enable for the created device. See the Extensions section for further details.

- `pEnabledFeatures` is `NULL` or a pointer to a VkPhysicalDeviceFeatures structure containing boolean indicators of all the features to be enabled. Refer to the Features section for further details.

Valid Usage

- The `queueFamilyIndex` member of each element of `pQueueCreateInfos` must be unique within `pQueueCreateInfos`, except that two members can share the same `queueFamilyIndex` if one is a protected-capable queue and one is not a protected-capable queue

- If the `pNext` chain includes a VkPhysicalDeviceFeatures2 structure, then `pEnabledFeatures` must be `NULL`

- `ppEnabledExtensionNames` must not contain `VK_AMD_negative_viewport_height`

- `ppEnabledExtensionNames` must not contain both `VK_KHR_buffer_device_address` and `VK_EXT_buffer_device_address`

- If the `pNext` chain includes a VkPhysicalDeviceVulkan11Features structure, then it must not include a VkPhysicalDevice16BitStorageFeatures, VkPhysicalDeviceMultiviewFeatures, VkPhysicalDeviceVariablePointersFeatures, VkPhysicalDeviceProtectedMemoryFeatures, VkPhysicalDeviceSamplerYcbcrConversionFeatures, or VkPhysicalDeviceShaderDrawParametersFeatures structure

- If the `pNext` chain includes a VkPhysicalDeviceVulkan12Features structure, then it must not include a VkPhysicalDevice8BitStorageFeatures, VkPhysicalDeviceShaderAtomicInt64Features, VkPhysicalDeviceShaderFloat16Int8Features, VkPhysicalDeviceDescriptorIndexingFeatures, VkPhysicalDeviceScalarBlockLayoutFeatures, VkPhysicalDeviceImagelessFramebufferFeatures, VkPhysicalDeviceUniformBufferStandardLayoutFeatures, VkPhysicalDeviceShaderSubgroupExtendedTypesFeatures, VkPhysicalDeviceSeparateDepthStencilLayoutsFeatures, VkPhysicalDeviceHostQueryResetFeatures, VkPhysicalDeviceTimelineSemaphoreFeatures, VkPhysicalDeviceBufferDeviceAddressFeatures, or VkPhysicalDeviceVulkanMemoryModelFeatures structure

- If `ppEnabledExtensions` contains `"VK_KHR_draw_indirect_count"` and the `pNext` chain includes a VkPhysicalDeviceVulkan12Features structure, then `VkPhysicalDeviceVulkan12Features`::`drawIndirectCount` must be `VK_TRUE`

- If `ppEnabledExtensions` contains `"VK_KHR_sampler_mirror_clamp_to_edge"` and the `pNext` chain includes a VkPhysicalDeviceVulkan12Features structure, then `VkPhysicalDeviceVulkan12Features`::`samplerMirrorClampToEdge` must be `VK_TRUE`

- If `ppEnabledExtensions` contains `"VK_EXT_descriptor_indexing"` and the `pNext` chain includes a VkPhysicalDeviceVulkan12Features structure, then `VkPhysicalDeviceVulkan12Features`::`descriptorIndexing` must be `VK_TRUE`

- If `ppEnabledExtensions` contains `"VK_EXT_sampler_filter_minmax"` and the `pNext` chain includes a VkPhysicalDeviceVulkan12Features structure, then `VkPhysicalDeviceVulkan12Features`::`samplerFilterMinmax` must be `VK_TRUE`

- If `ppEnabledExtensions` contains `"VK_EXT_shader_viewport_index_layer"` and the `pNext` chain includes a VkPhysicalDeviceVulkan12Features structure, then `VkPhysicalDeviceVulkan12Features`::`shaderOutputViewportIndex` and `VkPhysicalDeviceVulkan12Features`::`shaderOutputLayer` must both be `VK_TRUE`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkDeviceDiagnosticsConfigCreateInfoNV, VkDeviceGroupDeviceCreateInfo, VkDeviceMemoryOverallocationCreateInfoAMD, VkPhysicalDevice16BitStorageFeatures, VkPhysicalDevice8BitStorageFeatures, VkPhysicalDeviceASTCDecodeFeaturesEXT, VkPhysicalDeviceBlendOperationAdvancedFeaturesEXT, VkPhysicalDeviceBufferDeviceAddressFeatures, VkPhysicalDeviceBufferDeviceAddressFeaturesEXT, VkPhysicalDeviceCoherentMemoryFeaturesAMD, VkPhysicalDeviceComputeShaderDerivativesFeaturesNV, VkPhysicalDeviceConditionalRenderingFeaturesEXT, VkPhysicalDeviceCooperativeMatrixFeaturesNV, VkPhysicalDeviceCornerSampledImageFeaturesNV, VkPhysicalDeviceCoverageReductionModeFeaturesNV, VkPhysicalDeviceDedicatedAllocationImageAliasingFeaturesNV, VkPhysicalDeviceDepthClipEnableFeaturesEXT, VkPhysicalDeviceDescriptorIndexingFeatures, VkPhysicalDeviceDeviceGeneratedCommandsFeaturesNV, VkPhysicalDeviceDiagnosticsConfigFeaturesNV, VkPhysicalDeviceExclusiveScissorFeaturesNV, VkPhysicalDeviceFeatures2, VkPhysicalDeviceFragmentDensityMapFeaturesEXT, VkPhysicalDeviceFragmentShaderBarycentricFeaturesNV, VkPhysicalDeviceFragmentShaderInterlockFeaturesEXT, VkPhysicalDeviceHostQueryResetFeatures, VkPhysicalDeviceImagelessFramebufferFeatures, VkPhysicalDeviceIndexTypeUint8FeaturesEXT, VkPhysicalDeviceInlineUniformBlockFeaturesEXT, VkPhysicalDeviceLineRasterizationFeaturesEXT, VkPhysicalDeviceMemoryPriorityFeaturesEXT, VkPhysicalDeviceMeshShaderFeaturesNV, VkPhysicalDeviceMultiviewFeatures, VkPhysicalDevicePerformanceQueryFeaturesKHR, VkPhysicalDevicePipelineCreationCacheControlFeaturesEXT, VkPhysicalDevicePipelineExecutablePropertiesFeaturesKHR, VkPhysicalDeviceProtectedMemoryFeatures, VkPhysicalDeviceRayTracingFeaturesKHR, VkPhysicalDeviceRepresentativeFragmentTestFeaturesNV, VkPhysicalDeviceSamplerYcbcrConversionFeatures, VkPhysicalDeviceScalarBlockLayoutFeatures, VkPhysicalDeviceSeparateDepthStencilLayoutsFeatures, VkPhysicalDeviceShaderAtomicInt64Features, VkPhysicalDeviceShaderClockFeaturesKHR, VkPhysicalDeviceShaderDemoteToHelperInvocationFeaturesEXT, VkPhysicalDeviceShaderDrawParametersFeatures, VkPhysicalDeviceShaderFloat16Int8Features, VkPhysicalDeviceShaderImageFootprintFeaturesNV, VkPhysicalDeviceShaderIntegerFunctions2FeaturesINTEL, VkPhysicalDeviceShaderSMBuiltinsFeaturesNV, VkPhysicalDeviceShaderSubgroupExtendedTypesFeatures, VkPhysicalDeviceShadingRateImageFeaturesNV, VkPhysicalDeviceSubgroupSizeControlFeaturesEXT, VkPhysicalDeviceTexelBufferAlignmentFeaturesEXT, VkPhysicalDeviceTextureCompressionASTCHDRFeaturesEXT, VkPhysicalDeviceTimelineSemaphoreFeatures, VkPhysicalDeviceTransformFeedbackFeaturesEXT, VkPhysicalDeviceUniformBufferStandardLayoutFeatures, VkPhysicalDeviceVariablePointersFeatures, VkPhysicalDeviceVertexAttributeDivisorFeaturesEXT, VkPhysicalDeviceVulkan11Features, VkPhysicalDeviceVulkan12Features, VkPhysicalDeviceVulkanMemoryModelFeatures, or VkPhysicalDeviceYcbcrImageArraysFeaturesEXT

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be `0`

- `pQueueCreateInfos` must be a valid pointer to an array of `queueCreateInfoCount` valid VkDeviceQueueCreateInfo structures

- If `enabledLayerCount` is not `0`, `ppEnabledLayerNames` must be a valid pointer to an array of `enabledLayerCount` null-terminated UTF-8 strings

- If `enabledExtensionCount` is not `0`, `ppEnabledExtensionNames` must be a valid pointer to an array of `enabledExtensionCount` null-terminated UTF-8 strings

- If `pEnabledFeatures` is not `NULL`, `pEnabledFeatures` must be a valid pointer to a valid VkPhysicalDeviceFeatures structure

- `queueCreateInfoCount` must be greater than `0`

    typedef VkFlags VkDeviceCreateFlags;

`VkDeviceCreateFlags` is a bitmask type for setting a mask, but is currently reserved for future use.

A logical device can be created that connects to one or more physical devices by adding a `VkDeviceGroupDeviceCreateInfo` structure to the `pNext` chain of VkDeviceCreateInfo. The `VkDeviceGroupDeviceCreateInfo` structure is defined as:

    typedef struct VkDeviceGroupDeviceCreateInfo {
        VkStructureType            sType;
        const void*                pNext;
        uint32_t                   physicalDeviceCount;
        const VkPhysicalDevice*    pPhysicalDevices;
    } VkDeviceGroupDeviceCreateInfo;

or the equivalent

    typedef VkDeviceGroupDeviceCreateInfo VkDeviceGroupDeviceCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `physicalDeviceCount` is the number of elements in the `pPhysicalDevices` array.

- `pPhysicalDevices` is a pointer to an array of physical device handles belonging to the same device group.

The elements of the `pPhysicalDevices` array are an ordered list of the physical devices that the logical device represents. These must be a subset of a single device group, and need not be in the same order as they were enumerated. The order of the physical devices in the `pPhysicalDevices` array determines the device index of each physical device, with element i being assigned a device index of i. Certain commands and structures refer to one or more physical devices by using device indices or device masks formed using device indices.

A logical device created without using `VkDeviceGroupDeviceCreateInfo`, or with `physicalDeviceCount` equal to zero, is equivalent to a `physicalDeviceCount` of one and `pPhysicalDevices` pointing to the `physicalDevice` parameter to vkCreateDevice. In particular, the device index of that physical device is zero.

Valid Usage

- Each element of `pPhysicalDevices` must be unique

- All elements of `pPhysicalDevices` must be in the same device group as enumerated by vkEnumeratePhysicalDeviceGroups

- If `physicalDeviceCount` is not `0`, the `physicalDevice` parameter of vkCreateDevice must be an element of `pPhysicalDevices`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEVICE_GROUP_DEVICE_CREATE_INFO`

- If `physicalDeviceCount` is not `0`, `pPhysicalDevices` must be a valid pointer to an array of `physicalDeviceCount` valid VkPhysicalDevice handles

To specify whether device memory allocation is allowed beyond the size reported by VkPhysicalDeviceMemoryProperties, add a VkDeviceMemoryOverallocationCreateInfoAMD structure to the `pNext` chain of the VkDeviceCreateInfo structure. If this structure is not specified, it is as if the `VK_MEMORY_OVERALLOCATION_BEHAVIOR_DEFAULT_AMD` value is used.

    typedef struct VkDeviceMemoryOverallocationCreateInfoAMD {
        VkStructureType                      sType;
        const void*                          pNext;
        VkMemoryOverallocationBehaviorAMD    overallocationBehavior;
    } VkDeviceMemoryOverallocationCreateInfoAMD;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `overallocationBehavior` is the desired overallocation behavior.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEVICE_MEMORY_OVERALLOCATION_CREATE_INFO_AMD`

- `overallocationBehavior` must be a valid VkMemoryOverallocationBehaviorAMD value

Possible values for VkDeviceMemoryOverallocationCreateInfoAMD::overallocationBehavior include:

    typedef enum VkMemoryOverallocationBehaviorAMD {
        VK_MEMORY_OVERALLOCATION_BEHAVIOR_DEFAULT_AMD = 0,
        VK_MEMORY_OVERALLOCATION_BEHAVIOR_ALLOWED_AMD = 1,
        VK_MEMORY_OVERALLOCATION_BEHAVIOR_DISALLOWED_AMD = 2,
        VK_MEMORY_OVERALLOCATION_BEHAVIOR_MAX_ENUM_AMD = 0x7FFFFFFF
    } VkMemoryOverallocationBehaviorAMD;

- `VK_MEMORY_OVERALLOCATION_BEHAVIOR_DEFAULT_AMD` lets the implementation decide if overallocation should be allowed.

- `VK_MEMORY_OVERALLOCATION_BEHAVIOR_ALLOWED_AMD` specifies overallocation is allowed if platform permits.

- `VK_MEMORY_OVERALLOCATION_BEHAVIOR_DISALLOWED_AMD` specifies the application is not allowed to allocate device memory beyond the heap sizes reported by VkPhysicalDeviceMemoryProperties. Allocations that are not explicitly made by the application within the scope of the Vulkan instance are not accounted for.

When using the Nsight™ Aftermath SDK, to configure how device crash dumps are created, add a VkDeviceDiagnosticsConfigCreateInfoNV structure to the `pNext` chain of the VkDeviceCreateInfo structure.

    typedef struct VkDeviceDiagnosticsConfigCreateInfoNV {
        VkStructureType                     sType;
        const void*                         pNext;
        VkDeviceDiagnosticsConfigFlagsNV    flags;
    } VkDeviceDiagnosticsConfigCreateInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkDeviceDiagnosticsConfigFlagBitsNV specifying addtional parameters for configuring diagnostic tools.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEVICE_DIAGNOSTICS_CONFIG_CREATE_INFO_NV`

- `flags` must be a valid combination of VkDeviceDiagnosticsConfigFlagBitsNV values

Bits which can be set in VkDeviceDiagnosticsConfigCreateInfoNV::flags include:

    typedef enum VkDeviceDiagnosticsConfigFlagBitsNV {
        VK_DEVICE_DIAGNOSTICS_CONFIG_ENABLE_SHADER_DEBUG_INFO_BIT_NV = 0x00000001,
        VK_DEVICE_DIAGNOSTICS_CONFIG_ENABLE_RESOURCE_TRACKING_BIT_NV = 0x00000002,
        VK_DEVICE_DIAGNOSTICS_CONFIG_ENABLE_AUTOMATIC_CHECKPOINTS_BIT_NV = 0x00000004,
        VK_DEVICE_DIAGNOSTICS_CONFIG_FLAG_BITS_MAX_ENUM_NV = 0x7FFFFFFF
    } VkDeviceDiagnosticsConfigFlagBitsNV;

- `VK_DEVICE_DIAGNOSTICS_CONFIG_ENABLE_SHADER_DEBUG_INFO_BIT_NV` enables the generation of debug information for shaders.

- `VK_DEVICE_DIAGNOSTICS_CONFIG_ENABLE_RESOURCE_TRACKING_BIT_NV` enables driver side tracking of resources (images, buffers, etc.) used to augment the device fault information.

- `VK_DEVICE_DIAGNOSTICS_CONFIG_ENABLE_AUTOMATIC_CHECKPOINTS_BIT_NV` enables automatic insertion of diagnostic checkpoints for draw calls, dispatches, trace rays, and copies. The CPU call stack at the time of the command will be associated as the marker data for the automatically inserted checkpoints.

    typedef VkFlags VkDeviceDiagnosticsConfigFlagsNV;

`VkDeviceDiagnosticsConfigFlagsNV` is a bitmask type for setting a mask of zero or more VkDeviceDiagnosticsConfigFlagBitsNV.

#### 4.2.2. Device Use

The following is a high-level list of `VkDevice` uses along with references on where to find more information:

- Creation of queues. See the Queues section below for further details.

- Creation and tracking of various synchronization constructs. See Synchronization and Cache Control for further details.

- Allocating, freeing, and managing memory. See Memory Allocation and Resource Creation for further details.

- Creation and destruction of command buffers and command buffer pools. See Command Buffers for further details.

- Creation, destruction, and management of graphics state. See Pipelines and Resource Descriptors, among others, for further details.

#### 4.2.3. Lost Device

A logical device may become lost for a number of implementation-specific reasons, indicating that pending and future command execution may fail and cause resources and backing memory to become undefined.

| Note Typical reasons for device loss will include things like execution timing out (to prevent denial of service), power management events, platform resource management, implementation errors. Applications not adhering to valid usage may also result in device loss being reported, however this is not guaranteed. Even if device loss is reported, the system may be in an unrecoverable state, and further usage of the API is still considered invalid.

When this happens, certain commands will return `VK_ERROR_DEVICE_LOST` (see Error Codes for a list of such commands). After any such event, the logical device is considered lost. It is not possible to reset the logical device to a non-lost state, however the lost state is specific to a logical device (`VkDevice`), and the corresponding physical device (`VkPhysicalDevice`) may be otherwise unaffected.

In some cases, the physical device may also be lost, and attempting to create a new logical device will fail, returning `VK_ERROR_DEVICE_LOST`. This is usually indicative of a problem with the underlying implementation, or its connection to the host. If the physical device has not been lost, and a new logical device is successfully created from that physical device, it must be in the non-lost state.

| Note Whilst logical device loss may be recoverable, in the case of physical device loss, it is unlikely that an application will be able to recover unless additional, unaffected physical devices exist on the system. The error is largely informational and intended only to inform the user that a platform issue has occurred, and should be investigated further. For example, underlying hardware may have developed a fault or become physically disconnected from the rest of the system. In many cases, physical device loss may cause other more serious issues such as the operating system crashing; in which case it may not be reported via the Vulkan API.

When a device is lost, its child objects are not implicitly destroyed and their handles are still valid. Those objects must still be destroyed before their parents or the device can be destroyed (see the Object Lifetime section). The host address space corresponding to device memory mapped using vkMapMemory is still valid, and host memory accesses to these mapped regions are still valid, but the contents are undefined. It is still legal to call any API command on the device and child objects.

Once a device is lost, command execution may fail, and commands that return a VkResult may return `VK_ERROR_DEVICE_LOST`. Commands that do not allow run-time errors must still operate correctly for valid usage and, if applicable, return valid data.

Commands that wait indefinitely for device execution (namely vkDeviceWaitIdle, vkQueueWaitIdle, vkWaitForFences or vkAcquireNextImageKHR with a maximum `timeout`, and vkGetQueryPoolResults with the `VK_QUERY_RESULT_WAIT_BIT` bit set in `flags`) must return in finite time even in the case of a lost device, and return either `VK_SUCCESS` or `VK_ERROR_DEVICE_LOST`. For any command that may return `VK_ERROR_DEVICE_LOST`, for the purpose of determining whether a command buffer is in the pending state, or whether resources are considered in-use by the device, a return value of `VK_ERROR_DEVICE_LOST` is equivalent to `VK_SUCCESS`.

The content of any external memory objects that have been exported from or imported to a lost device become undefined. Objects on other logical devices or in other APIs which are associated with the same underlying memory resource as the external memory objects on the lost device are unaffected other than their content becoming undefined. The layout of subresources of images on other logical devices that are bound to `VkDeviceMemory` objects associated with the same underlying memory resources as external memory objects on the lost device becomes `VK_IMAGE_LAYOUT_UNDEFINED`.

The state of `VkSemaphore` objects on other logical devices created by importing a semaphore payload with temporary permanence which was exported from the lost device is undefined. The state of `VkSemaphore` objects on other logical devices that permanently share a semaphore payload with a `VkSemaphore` object on the lost device is undefined, and remains undefined following any subsequent signal operations. Implementations must ensure pending and subsequently submitted wait operations on such semaphores behave as defined in Semaphore State Requirements For Wait Operations for external semaphores not in a valid state for a wait operation.

| editing-note TODO (piman) - I do not think we are very clear about what “in-use by the device” means.

#### 4.2.4. Device Destruction

To destroy a device, call:

    void vkDestroyDevice(
        VkDevice                                    device,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

To ensure that no work is active on the device, vkDeviceWaitIdle can be used to gate the destruction of the device. Prior to destroying a device, an application is responsible for destroying/freeing any Vulkan objects that were created using that device as the first parameter of the corresponding `vkCreate*` or `vkAllocate*` command.

| Note The lifetime of each of these objects is bound by the lifetime of the `VkDevice` object. Therefore, to avoid resource leaks, it is critical that an application explicitly free all of these resources prior to calling `vkDestroyDevice`.

Valid Usage

- All child objects created on `device` must have been destroyed prior to destroying `device`

- If `VkAllocationCallbacks` were provided when `device` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `device` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- If `device` is not `NULL`, `device` must be a valid VkDevice handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

Host Synchronization

- Host access to `device` must be externally synchronized

### 4.3. Queues

#### 4.3.1. Queue Family Properties

As discussed in the Physical Device Enumeration section above, the vkGetPhysicalDeviceQueueFamilyProperties command is used to retrieve details about the queue families and queues supported by a device.

Each index in the `pQueueFamilyProperties` array returned by vkGetPhysicalDeviceQueueFamilyProperties describes a unique queue family on that physical device. These indices are used when creating queues, and they correspond directly with the `queueFamilyIndex` that is passed to the vkCreateDevice command via the VkDeviceQueueCreateInfo structure as described in the Queue Creation section below.

Grouping of queue families within a physical device is implementation-dependent.

| Note The general expectation is that a physical device groups all queues of matching capabilities into a single family. However, while implementations should do this, it is possible that a physical device may return two separate queue families with the same capabilities.

Once an application has identified a physical device with the queue(s) that it desires to use, it will create those queues in conjunction with a logical device. This is described in the following section.

#### 4.3.2. Queue Creation

Creating a logical device also creates the queues associated with that device. The queues to create are described by a set of VkDeviceQueueCreateInfo structures that are passed to vkCreateDevice in `pQueueCreateInfos`.

Queues are represented by `VkQueue` handles:

    VK_DEFINE_HANDLE(VkQueue)

The `VkDeviceQueueCreateInfo` structure is defined as:

    typedef struct VkDeviceQueueCreateInfo {
        VkStructureType             sType;
        const void*                 pNext;
        VkDeviceQueueCreateFlags    flags;
        uint32_t                    queueFamilyIndex;
        uint32_t                    queueCount;
        const float*                pQueuePriorities;
    } VkDeviceQueueCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask indicating behavior of the queue.

- `queueFamilyIndex` is an unsigned integer indicating the index of the queue family to create on this device. This index corresponds to the index of an element of the `pQueueFamilyProperties` array that was returned by `vkGetPhysicalDeviceQueueFamilyProperties`.

- `queueCount` is an unsigned integer specifying the number of queues to create in the queue family indicated by `queueFamilyIndex`.

- `pQueuePriorities` is a pointer to an array of `queueCount` normalized floating point values, specifying priorities of work that will be submitted to each created queue. See Queue Priority for more information.

Valid Usage

- `queueFamilyIndex` must be less than `pQueueFamilyPropertyCount` returned by `vkGetPhysicalDeviceQueueFamilyProperties`

- `queueCount` must be less than or equal to the `queueCount` member of the `VkQueueFamilyProperties` structure, as returned by `vkGetPhysicalDeviceQueueFamilyProperties` in the `pQueueFamilyProperties`[queueFamilyIndex]

- Each element of `pQueuePriorities` must be between `0.0` and `1.0` inclusive

- If the protected memory feature is not enabled, the `VK_DEVICE_QUEUE_CREATE_PROTECTED_BIT` bit of `flags` must not be set.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEVICE_QUEUE_CREATE_INFO`

- `pNext` must be `NULL` or a pointer to a valid instance of VkDeviceQueueGlobalPriorityCreateInfoEXT

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be a valid combination of VkDeviceQueueCreateFlagBits values

- `pQueuePriorities` must be a valid pointer to an array of `queueCount` `float` values

- `queueCount` must be greater than `0`

Bits which can be set in VkDeviceQueueCreateInfo::`flags` to specify usage behavior of the queue are:

    typedef enum VkDeviceQueueCreateFlagBits {
        VK_DEVICE_QUEUE_CREATE_PROTECTED_BIT = 0x00000001,
        VK_DEVICE_QUEUE_CREATE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkDeviceQueueCreateFlagBits;

- `VK_DEVICE_QUEUE_CREATE_PROTECTED_BIT` specifies that the device queue is a protected-capable queue.

    typedef VkFlags VkDeviceQueueCreateFlags;

`VkDeviceQueueCreateFlags` is a bitmask type for setting a mask of zero or more VkDeviceQueueCreateFlagBits.

A queue can be created with a system-wide priority by adding a `VkDeviceQueueGlobalPriorityCreateInfoEXT` structure to the `pNext` chain of VkDeviceQueueCreateInfo.

The `VkDeviceQueueGlobalPriorityCreateInfoEXT` structure is defined as:

    typedef struct VkDeviceQueueGlobalPriorityCreateInfoEXT {
        VkStructureType             sType;
        const void*                 pNext;
        VkQueueGlobalPriorityEXT    globalPriority;
    } VkDeviceQueueGlobalPriorityCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `globalPriority` is the system-wide priority associated to this queue as specified by VkQueueGlobalPriorityEXT

A queue created without specifying `VkDeviceQueueGlobalPriorityCreateInfoEXT` will default to `VK_QUEUE_GLOBAL_PRIORITY_MEDIUM_EXT`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEVICE_QUEUE_GLOBAL_PRIORITY_CREATE_INFO_EXT`

- `globalPriority` must be a valid VkQueueGlobalPriorityEXT value

Possible values of VkDeviceQueueGlobalPriorityCreateInfoEXT::`globalPriority`, specifying a system-wide priority level are:

    typedef enum VkQueueGlobalPriorityEXT {
        VK_QUEUE_GLOBAL_PRIORITY_LOW_EXT = 128,
        VK_QUEUE_GLOBAL_PRIORITY_MEDIUM_EXT = 256,
        VK_QUEUE_GLOBAL_PRIORITY_HIGH_EXT = 512,
        VK_QUEUE_GLOBAL_PRIORITY_REALTIME_EXT = 1024,
        VK_QUEUE_GLOBAL_PRIORITY_MAX_ENUM_EXT = 0x7FFFFFFF
    } VkQueueGlobalPriorityEXT;

Priority values are sorted in ascending order. A comparison operation on the enum values can be used to determine the priority order.

- `VK_QUEUE_GLOBAL_PRIORITY_LOW_EXT` is below the system default. Useful for non-interactive tasks.

- `VK_QUEUE_GLOBAL_PRIORITY_MEDIUM_EXT` is the system default priority.

- `VK_QUEUE_GLOBAL_PRIORITY_HIGH_EXT` is above the system default.

- `VK_QUEUE_GLOBAL_PRIORITY_REALTIME_EXT` is the highest priority. Useful for critical tasks.

Queues with higher system priority may be allotted more processing time than queues with lower priority. An implementation may allow a higher-priority queue to starve a lower-priority queue until the higher-priority queue has no further commands to execute.

Priorities imply no ordering or scheduling constraints.

No specific guarantees are made about higher priority queues receiving more processing time or better quality of service than lower priority queues.

The global priority level of a queue takes precedence over the per-process queue priority (`VkDeviceQueueCreateInfo`::`pQueuePriorities`).

Abuse of this feature may result in starving the rest of the system of implementation resources. Therefore, the driver implementation may deny requests to acquire a priority above the default priority (`VK_QUEUE_GLOBAL_PRIORITY_MEDIUM_EXT`) if the caller does not have sufficient privileges. In this scenario `VK_ERROR_NOT_PERMITTED_EXT` is returned.

The driver implementation may fail the queue allocation request if resources required to complete the operation have been exhausted (either by the same process or a different process). In this scenario `VK_ERROR_INITIALIZATION_FAILED` is returned.

To retrieve a handle to a VkQueue object, call:

    void vkGetDeviceQueue(
        VkDevice                                    device,
        uint32_t                                    queueFamilyIndex,
        uint32_t                                    queueIndex,
        VkQueue*                                    pQueue);

- `device` is the logical device that owns the queue.

- `queueFamilyIndex` is the index of the queue family to which the queue belongs.

- `queueIndex` is the index within this queue family of the queue to retrieve.

- `pQueue` is a pointer to a VkQueue object that will be filled with the handle for the requested queue.

`vkGetDeviceQueue` must only be used to get queues that were created with the `flags` parameter of `VkDeviceQueueCreateInfo` set to zero. To get queues that were created with a non-zero `flags` parameter use vkGetDeviceQueue2.

Valid Usage

- `queueFamilyIndex` must be one of the queue family indices specified when `device` was created, via the `VkDeviceQueueCreateInfo` structure

- `queueIndex` must be less than the number of queues created for the specified queue family index when `device` was created, via the `queueCount` member of the `VkDeviceQueueCreateInfo` structure

- VkDeviceQueueCreateInfo::`flags` must have been set to zero when `device` was created

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pQueue` must be a valid pointer to a VkQueue handle

To retrieve a handle to a VkQueue object with specific VkDeviceQueueCreateFlags creation flags, call:

    void vkGetDeviceQueue2(
        VkDevice                                    device,
        const VkDeviceQueueInfo2*                   pQueueInfo,
        VkQueue*                                    pQueue);

- `device` is the logical device that owns the queue.

- `pQueueInfo` is a pointer to a VkDeviceQueueInfo2 structure, describing the parameters used to create the device queue.

- `pQueue` is a pointer to a VkQueue object that will be filled with the handle for the requested queue.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pQueueInfo` must be a valid pointer to a valid VkDeviceQueueInfo2 structure

- `pQueue` must be a valid pointer to a VkQueue handle

The `VkDeviceQueueInfo2` structure is defined as:

    typedef struct VkDeviceQueueInfo2 {
        VkStructureType             sType;
        const void*                 pNext;
        VkDeviceQueueCreateFlags    flags;
        uint32_t                    queueFamilyIndex;
        uint32_t                    queueIndex;
    } VkDeviceQueueInfo2;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure. The `pNext` chain of `VkDeviceQueueInfo2` is used to provide additional image parameters to `vkGetDeviceQueue2`.

- `flags` is a VkDeviceQueueCreateFlags value indicating the flags used to create the device queue.

- `queueFamilyIndex` is the index of the queue family to which the queue belongs.

- `queueIndex` is the index within this queue family of the queue to retrieve.

The queue returned by `vkGetDeviceQueue2` must have the same `flags` value from this structure as that used at device creation time in a `VkDeviceQueueCreateInfo` instance. If no matching `flags` were specified at device creation time then `pQueue` will return VK_NULL_HANDLE.

Valid Usage

- `queueFamilyIndex` must be one of the queue family indices specified when `device` was created, via the `VkDeviceQueueCreateInfo` structure

- `queueIndex` must be less than the number of queues created for the specified queue family index and VkDeviceQueueCreateFlags member `flags` equal to this `flags` value when `device` was created, via the `queueCount` member of the `VkDeviceQueueCreateInfo` structure

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEVICE_QUEUE_INFO_2`

- `pNext` must be `NULL`

- `flags` must be a valid combination of VkDeviceQueueCreateFlagBits values

#### 4.3.3. Queue Family Index

The queue family index is used in multiple places in Vulkan in order to tie operations to a specific family of queues.

When retrieving a handle to the queue via `vkGetDeviceQueue`, the queue family index is used to select which queue family to retrieve the `VkQueue` handle from as described in the previous section.

When creating a `VkCommandPool` object (see Command Pools), a queue family index is specified in the VkCommandPoolCreateInfo structure. Command buffers from this pool can only be submitted on queues corresponding to this queue family.

When creating `VkImage` (see Images) and `VkBuffer` (see Buffers) resources, a set of queue families is included in the VkImageCreateInfo and VkBufferCreateInfo structures to specify the queue families that can access the resource.

When inserting a VkBufferMemoryBarrier or VkImageMemoryBarrier (see Pipeline Barriers), a source and destination queue family index is specified to allow the ownership of a buffer or image to be transferred from one queue family to another. See the Resource Sharing section for details.

#### 4.3.4. Queue Priority

Each queue is assigned a priority, as set in the VkDeviceQueueCreateInfo structures when creating the device. The priority of each queue is a normalized floating point value between 0.0 and 1.0, which is then translated to a discrete priority level by the implementation. Higher values indicate a higher priority, with 0.0 being the lowest priority and 1.0 being the highest.

Within the same device, queues with higher priority may be allotted more processing time than queues with lower priority. The implementation makes no guarantees with regards to ordering or scheduling among queues with the same priority, other than the constraints defined by any explicit synchronization primitives. The implementation make no guarantees with regards to queues across different devices.

An implementation may allow a higher-priority queue to starve a lower-priority queue on the same `VkDevice` until the higher-priority queue has no further commands to execute. The relationship of queue priorities must not cause queues on one `VkDevice` to starve queues on another `VkDevice`.

No specific guarantees are made about higher priority queues receiving more processing time or better quality of service than lower priority queues.

#### 4.3.5. Queue Submission

Work is submitted to a queue via queue submission commands such as vkQueueSubmit. Queue submission commands define a set of queue operations to be executed by the underlying physical device, including synchronization with semaphores and fences.

Submission commands take as parameters a target queue, zero or more batches of work, and an optional fence to signal upon completion. Each batch consists of three distinct parts:

1. Zero or more semaphores to wait on before execution of the rest of the batch.

   - If present, these describe a semaphore wait operation.

2. Zero or more work items to execute.

   - If present, these describe a queue operation matching the work described.

3. Zero or more semaphores to signal upon completion of the work items.

   - If present, these describe a semaphore signal operation.

If a fence is present in a queue submission, it describes a fence signal operation.

All work described by a queue submission command must be submitted to the queue before the command returns.

##### Sparse Memory Binding

In Vulkan it is possible to sparsely bind memory to buffers and images as described in the Sparse Resource chapter. Sparse memory binding is a queue operation. A queue whose flags include the `VK_QUEUE_SPARSE_BINDING_BIT` must be able to support the mapping of a virtual address to a physical address on the device. This causes an update to the page table mappings on the device. This update must be synchronized on a queue to avoid corrupting page table mappings during execution of graphics commands. By binding the sparse memory resources on queues, all commands that are dependent on the updated bindings are synchronized to only execute after the binding is updated. See the Synchronization and Cache Control chapter for how this synchronization is accomplished.

#### 4.3.6. Queue Destruction

Queues are created along with a logical device during `vkCreateDevice`. All queues associated with a logical device are destroyed when `vkDestroyDevice` is called on that device.

## 5. Command Buffers

Command buffers are objects used to record commands which can be subsequently submitted to a device queue for execution. There are two levels of command buffers - primary command buffers, which can execute secondary command buffers, and which are submitted to queues, and secondary command buffers, which can be executed by primary command buffers, and which are not directly submitted to queues.

Command buffers are represented by `VkCommandBuffer` handles:

    VK_DEFINE_HANDLE(VkCommandBuffer)

Recorded commands include commands to bind pipelines and descriptor sets to the command buffer, commands to modify dynamic state, commands to draw (for graphics rendering), commands to dispatch (for compute), commands to execute secondary command buffers (for primary command buffers only), commands to copy buffers and images, and other commands.

Each command buffer manages state independently of other command buffers. There is no inheritance of state across primary and secondary command buffers, or between secondary command buffers. When a command buffer begins recording, all state in that command buffer is undefined. When secondary command buffer(s) are recorded to execute on a primary command buffer, the secondary command buffer inherits no state from the primary command buffer, and all state of the primary command buffer is undefined after an execute secondary command buffer command is recorded. There is one exception to this rule - if the primary command buffer is inside a render pass instance, then the render pass and subpass state is not disturbed by executing secondary command buffers. For state dependent commands (such as draws and dispatches), any state consumed by those commands must not be undefined.

Unless otherwise specified, and without explicit synchronization, the various commands submitted to a queue via command buffers may execute in arbitrary order relative to each other, and/or concurrently. Also, the memory side-effects of those commands may not be directly visible to other commands without explicit memory dependencies. This is true within a command buffer, and across command buffers submitted to a given queue. See the synchronization chapter for information on implicit and explicit synchronization between commands.

### 5.1. Command Buffer Lifecycle

Each command buffer is always in one of the following states:

Initial

  When a command buffer is allocated, it is in the initial state. Some commands are able to reset a command buffer (or a set of command buffers) back to this state from any of the executable, recording or invalid state. Command buffers in the initial state can only be moved to the recording state, or freed.

Recording

  vkBeginCommandBuffer changes the state of a command buffer from the initial state to the recording state. Once a command buffer is in the recording state, `vkCmd*` commands can be used to record to the command buffer.

Executable

  vkEndCommandBuffer ends the recording of a command buffer, and moves it from the recording state to the executable state. Executable command buffers can be submitted, reset, or recorded to another command buffer.

Pending

  Queue submission of a command buffer changes the state of a command buffer from the executable state to the pending state. Whilst in the pending state, applications must not attempt to modify the command buffer in any way - as the device may be processing the commands recorded to it. Once execution of a command buffer completes, the command buffer either reverts back to the executable state, or if it was recorded with `VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT`, it moves to the invalid state. A synchronization command should be used to detect when this occurs.

Invalid

  Some operations, such as modifying or deleting a resource that was used in a command recorded to a command buffer, will transition the state of that command buffer into the invalid state. Command buffers in the invalid state can only be reset or freed.

Figure 1. Lifecycle of a command buffer

Any given command that operates on a command buffer has its own requirements on what state a command buffer must be in, which are detailed in the valid usage constraints for that command.

Resetting a command buffer is an operation that discards any previously recorded commands and puts a command buffer in the initial state. Resetting occurs as a result of vkResetCommandBuffer or vkResetCommandPool, or as part of vkBeginCommandBuffer (which additionally puts the command buffer in the recording state).

Secondary command buffers can be recorded to a primary command buffer via vkCmdExecuteCommands. This partially ties the lifecycle of the two command buffers together - if the primary is submitted to a queue, both the primary and any secondaries recorded to it move to the pending state. Once execution of the primary completes, so it does for any secondary recorded within it. After all executions of each command buffer complete, they each move to their appropriate completion state (either to the execution state or the invalid state, as specified above).

If a secondary moves to the invalid state or the initial state, then all primary buffers it is recorded in move to the invalid state. A primary moving to any other state does not affect the state of a secondary recorded in it.

| Note Resetting or freeing a primary command buffer removes the lifecycle linkage to all secondary command buffers that were recorded into it.

### 5.2. Command Pools

Command pools are opaque objects that command buffer memory is allocated from, and which allow the implementation to amortize the cost of resource creation across multiple command buffers. Command pools are externally synchronized, meaning that a command pool must not be used concurrently in multiple threads. That includes use via recording commands on any command buffers allocated from the pool, as well as operations that allocate, free, and reset command buffers or the pool itself.

Command pools are represented by `VkCommandPool` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkCommandPool)

To create a command pool, call:

    VkResult vkCreateCommandPool(
        VkDevice                                    device,
        const VkCommandPoolCreateInfo*              pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkCommandPool*                              pCommandPool);

- `device` is the logical device that creates the command pool.

- `pCreateInfo` is a pointer to a VkCommandPoolCreateInfo structure specifying the state of the command pool object.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pCommandPool` is a pointer to a VkCommandPool handle in which the created pool is returned.

Valid Usage

- `pCreateInfo->queueFamilyIndex` must be the index of a queue family available in the logical device `device`.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkCommandPoolCreateInfo structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pCommandPool` must be a valid pointer to a VkCommandPool handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkCommandPoolCreateInfo` structure is defined as:

    typedef struct VkCommandPoolCreateInfo {
        VkStructureType             sType;
        const void*                 pNext;
        VkCommandPoolCreateFlags    flags;
        uint32_t                    queueFamilyIndex;
    } VkCommandPoolCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkCommandPoolCreateFlagBits indicating usage behavior for the pool and command buffers allocated from it.

- `queueFamilyIndex` designates a queue family as described in section Queue Family Properties. All command buffers allocated from this command pool must be submitted on queues from the same queue family.

Valid Usage

- If the protected memory feature is not enabled, the `VK_COMMAND_POOL_CREATE_PROTECTED_BIT` bit of `flags` must not be set.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_COMMAND_POOL_CREATE_INFO`

- `pNext` must be `NULL`

- `flags` must be a valid combination of VkCommandPoolCreateFlagBits values

Bits which can be set in VkCommandPoolCreateInfo::`flags` to specify usage behavior for a command pool are:

    typedef enum VkCommandPoolCreateFlagBits {
        VK_COMMAND_POOL_CREATE_TRANSIENT_BIT = 0x00000001,
        VK_COMMAND_POOL_CREATE_RESET_COMMAND_BUFFER_BIT = 0x00000002,
        VK_COMMAND_POOL_CREATE_PROTECTED_BIT = 0x00000004,
        VK_COMMAND_POOL_CREATE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkCommandPoolCreateFlagBits;

- `VK_COMMAND_POOL_CREATE_TRANSIENT_BIT` specifies that command buffers allocated from the pool will be short-lived, meaning that they will be reset or freed in a relatively short timeframe. This flag may be used by the implementation to control memory allocation behavior within the pool.

- `VK_COMMAND_POOL_CREATE_RESET_COMMAND_BUFFER_BIT` allows any command buffer allocated from a pool to be individually reset to the initial state; either by calling vkResetCommandBuffer, or via the implicit reset when calling vkBeginCommandBuffer. If this flag is not set on a pool, then `vkResetCommandBuffer` must not be called for any command buffer allocated from that pool.

- `VK_COMMAND_POOL_CREATE_PROTECTED_BIT` specifies that command buffers allocated from the pool are protected command buffers.

    typedef VkFlags VkCommandPoolCreateFlags;

`VkCommandPoolCreateFlags` is a bitmask type for setting a mask of zero or more VkCommandPoolCreateFlagBits.

To trim a command pool, call:

    void vkTrimCommandPool(
        VkDevice                                    device,
        VkCommandPool                               commandPool,
        VkCommandPoolTrimFlags                      flags);

or the equivalent command

    void vkTrimCommandPoolKHR(
        VkDevice                                    device,
        VkCommandPool                               commandPool,
        VkCommandPoolTrimFlags                      flags);

- `device` is the logical device that owns the command pool.

- `commandPool` is the command pool to trim.

- `flags` is reserved for future use.

Trimming a command pool recycles unused memory from the command pool back to the system. Command buffers allocated from the pool are not affected by the command.

| Note This command provides applications with some control over the internal memory allocations used by command pools. Unused memory normally arises from command buffers that have been recorded and later reset, such that they are no longer using the memory. On reset, a command buffer can return memory to its command pool, but the only way to release memory from a command pool to the system requires calling vkResetCommandPool, which cannot be executed while any command buffers from that pool are still in use. Subsequent recording operations into command buffers will re-use this memory but since total memory requirements fluctuate over time, unused memory can accumulate. In this situation, trimming a command pool may be useful to return unused memory back to the system, returning the total outstanding memory allocated by the pool back to a more “average” value. Implementations utilize many internal allocation strategies that make it impossible to guarantee that all unused memory is released back to the system. For instance, an implementation of a command pool may involve allocating memory in bulk from the system and sub-allocating from that memory. In such an implementation any live command buffer that holds a reference to a bulk allocation would prevent that allocation from being freed, even if only a small proportion of the bulk allocation is in use. In most cases trimming will result in a reduction in allocated but unused memory, but it does not guarantee the “ideal” behavior. Trimming may be an expensive operation, and should not be called frequently. Trimming should be treated as a way to relieve memory pressure after application-known points when there exists enough unused memory that the cost of trimming is “worth” it.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `commandPool` must be a valid VkCommandPool handle

- `flags` must be `0`

- `commandPool` must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `commandPool` must be externally synchronized

    typedef VkFlags VkCommandPoolTrimFlags;

or the equivalent

    typedef VkCommandPoolTrimFlags VkCommandPoolTrimFlagsKHR;

`VkCommandPoolTrimFlags` is a bitmask type for setting a mask, but is currently reserved for future use.

To reset a command pool, call:

    VkResult vkResetCommandPool(
        VkDevice                                    device,
        VkCommandPool                               commandPool,
        VkCommandPoolResetFlags                     flags);

- `device` is the logical device that owns the command pool.

- `commandPool` is the command pool to reset.

- `flags` is a bitmask of VkCommandPoolResetFlagBits controlling the reset operation.

Resetting a command pool recycles all of the resources from all of the command buffers allocated from the command pool back to the command pool. All command buffers that have been allocated from the command pool are put in the initial state.

Any primary command buffer allocated from another VkCommandPool that is in the recording or executable state and has a secondary command buffer allocated from `commandPool` recorded into it, becomes invalid.

Valid Usage

- All `VkCommandBuffer` objects allocated from `commandPool` must not be in the pending state

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `commandPool` must be a valid VkCommandPool handle

- `flags` must be a valid combination of VkCommandPoolResetFlagBits values

- `commandPool` must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `commandPool` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

Bits which can be set in vkResetCommandPool::`flags` to control the reset operation are:

    typedef enum VkCommandPoolResetFlagBits {
        VK_COMMAND_POOL_RESET_RELEASE_RESOURCES_BIT = 0x00000001,
        VK_COMMAND_POOL_RESET_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkCommandPoolResetFlagBits;

- `VK_COMMAND_POOL_RESET_RELEASE_RESOURCES_BIT` specifies that resetting a command pool recycles all of the resources from the command pool back to the system.

    typedef VkFlags VkCommandPoolResetFlags;

`VkCommandPoolResetFlags` is a bitmask type for setting a mask of zero or more VkCommandPoolResetFlagBits.

To destroy a command pool, call:

    void vkDestroyCommandPool(
        VkDevice                                    device,
        VkCommandPool                               commandPool,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that destroys the command pool.

- `commandPool` is the handle of the command pool to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

When a pool is destroyed, all command buffers allocated from the pool are freed.

Any primary command buffer allocated from another VkCommandPool that is in the recording or executable state and has a secondary command buffer allocated from `commandPool` recorded into it, becomes invalid.

Valid Usage

- All `VkCommandBuffer` objects allocated from `commandPool` must not be in the pending state.

- If `VkAllocationCallbacks` were provided when `commandPool` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `commandPool` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `commandPool` is not VK_NULL_HANDLE, `commandPool` must be a valid VkCommandPool handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- If `commandPool` is a valid handle, it must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `commandPool` must be externally synchronized

### 5.3. Command Buffer Allocation and Management

To allocate command buffers, call:

    VkResult vkAllocateCommandBuffers(
        VkDevice                                    device,
        const VkCommandBufferAllocateInfo*          pAllocateInfo,
        VkCommandBuffer*                            pCommandBuffers);

- `device` is the logical device that owns the command pool.

- `pAllocateInfo` is a pointer to a `VkCommandBufferAllocateInfo` structure describing parameters of the allocation.

- `pCommandBuffers` is a pointer to an array of VkCommandBuffer handles in which the resulting command buffer objects are returned. The array must be at least the length specified by the `commandBufferCount` member of `pAllocateInfo`. Each allocated command buffer begins in the initial state.

`vkAllocateCommandBuffers` can be used to create multiple command buffers. If the creation of any of those command buffers fails, the implementation must destroy all successfully created command buffer objects from this command, set all entries of the `pCommandBuffers` array to `NULL` and return the error.

When command buffers are first allocated, they are in the initial state.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pAllocateInfo` must be a valid pointer to a valid VkCommandBufferAllocateInfo structure

- `pCommandBuffers` must be a valid pointer to an array of `pAllocateInfo`::commandBufferCount VkCommandBuffer handles

- The value referenced by `pAllocateInfo`::`commandBufferCount` must be greater than `0`

Host Synchronization

- Host access to `pAllocateInfo`::commandPool must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkCommandBufferAllocateInfo` structure is defined as:

    typedef struct VkCommandBufferAllocateInfo {
        VkStructureType         sType;
        const void*             pNext;
        VkCommandPool           commandPool;
        VkCommandBufferLevel    level;
        uint32_t                commandBufferCount;
    } VkCommandBufferAllocateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `commandPool` is the command pool from which the command buffers are allocated.

- `level` is a VkCommandBufferLevel value specifying the command buffer level.

- `commandBufferCount` is the number of command buffers to allocate from the pool.

Valid Usage

- `commandBufferCount` must be greater than `0`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO`

- `pNext` must be `NULL`

- `commandPool` must be a valid VkCommandPool handle

- `level` must be a valid VkCommandBufferLevel value

Possible values of VkCommandBufferAllocateInfo::`level`, specifying the command buffer level, are:

    typedef enum VkCommandBufferLevel {
        VK_COMMAND_BUFFER_LEVEL_PRIMARY = 0,
        VK_COMMAND_BUFFER_LEVEL_SECONDARY = 1,
        VK_COMMAND_BUFFER_LEVEL_MAX_ENUM = 0x7FFFFFFF
    } VkCommandBufferLevel;

- `VK_COMMAND_BUFFER_LEVEL_PRIMARY` specifies a primary command buffer.

- `VK_COMMAND_BUFFER_LEVEL_SECONDARY` specifies a secondary command buffer.

To reset command buffers, call:

    VkResult vkResetCommandBuffer(
        VkCommandBuffer                             commandBuffer,
        VkCommandBufferResetFlags                   flags);

- `commandBuffer` is the command buffer to reset. The command buffer can be in any state other than pending, and is moved into the initial state.

- `flags` is a bitmask of VkCommandBufferResetFlagBits controlling the reset operation.

Any primary command buffer that is in the recording or executable state and has `commandBuffer` recorded into it, becomes invalid.

Valid Usage

- `commandBuffer` must not be in the pending state

- `commandBuffer` must have been allocated from a pool that was created with the `VK_COMMAND_POOL_CREATE_RESET_COMMAND_BUFFER_BIT`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `flags` must be a valid combination of VkCommandBufferResetFlagBits values

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

Bits which can be set in vkResetCommandBuffer::`flags` to control the reset operation are:

    typedef enum VkCommandBufferResetFlagBits {
        VK_COMMAND_BUFFER_RESET_RELEASE_RESOURCES_BIT = 0x00000001,
        VK_COMMAND_BUFFER_RESET_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkCommandBufferResetFlagBits;

- `VK_COMMAND_BUFFER_RESET_RELEASE_RESOURCES_BIT` specifies that most or all memory resources currently owned by the command buffer should be returned to the parent command pool. If this flag is not set, then the command buffer may hold onto memory resources and reuse them when recording commands. `commandBuffer` is moved to the initial state.

    typedef VkFlags VkCommandBufferResetFlags;

`VkCommandBufferResetFlags` is a bitmask type for setting a mask of zero or more VkCommandBufferResetFlagBits.

To free command buffers, call:

    void vkFreeCommandBuffers(
        VkDevice                                    device,
        VkCommandPool                               commandPool,
        uint32_t                                    commandBufferCount,
        const VkCommandBuffer*                      pCommandBuffers);

- `device` is the logical device that owns the command pool.

- `commandPool` is the command pool from which the command buffers were allocated.

- `commandBufferCount` is the length of the `pCommandBuffers` array.

- `pCommandBuffers` is a pointer to an array of handles of command buffers to free.

Any primary command buffer that is in the recording or executable state and has any element of `pCommandBuffers` recorded into it, becomes invalid.

Valid Usage

- All elements of `pCommandBuffers` must not be in the pending state

- `pCommandBuffers` must be a valid pointer to an array of `commandBufferCount` `VkCommandBuffer` handles, each element of which must either be a valid handle or `NULL`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `commandPool` must be a valid VkCommandPool handle

- `commandBufferCount` must be greater than `0`

- `commandPool` must have been created, allocated, or retrieved from `device`

- Each element of `pCommandBuffers` that is a valid handle must have been created, allocated, or retrieved from `commandPool`

Host Synchronization

- Host access to `commandPool` must be externally synchronized

- Host access to each member of `pCommandBuffers` must be externally synchronized

### 5.4. Command Buffer Recording

To begin recording a command buffer, call:

    VkResult vkBeginCommandBuffer(
        VkCommandBuffer                             commandBuffer,
        const VkCommandBufferBeginInfo*             pBeginInfo);

- `commandBuffer` is the handle of the command buffer which is to be put in the recording state.

- `pBeginInfo` points to a VkCommandBufferBeginInfo structure defining additional information about how the command buffer begins recording.

Valid Usage

- `commandBuffer` must not be in the recording or pending state

- If `commandBuffer` was allocated from a VkCommandPool which did not have the `VK_COMMAND_POOL_CREATE_RESET_COMMAND_BUFFER_BIT` flag set, `commandBuffer` must be in the initial state

- If `commandBuffer` is a secondary command buffer, the `pInheritanceInfo` member of `pBeginInfo` must be a valid `VkCommandBufferInheritanceInfo` structure

- If `commandBuffer` is a secondary command buffer and either the `occlusionQueryEnable` member of the `pInheritanceInfo` member of `pBeginInfo` is `VK_FALSE`, or the precise occlusion queries feature is not enabled, the `queryFlags` member of the `pInheritanceInfo` member `pBeginInfo` must not contain `VK_QUERY_CONTROL_PRECISE_BIT`

- If `commandBuffer` is a primary command buffer, then `pBeginInfo->flags` must not set both the `VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT` and the `VK_COMMAND_BUFFER_USAGE_SIMULTANEOUS_USE_BIT` flags

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pBeginInfo` must be a valid pointer to a valid VkCommandBufferBeginInfo structure

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkCommandBufferBeginInfo` structure is defined as:

    typedef struct VkCommandBufferBeginInfo {
        VkStructureType                          sType;
        const void*                              pNext;
        VkCommandBufferUsageFlags                flags;
        const VkCommandBufferInheritanceInfo*    pInheritanceInfo;
    } VkCommandBufferBeginInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkCommandBufferUsageFlagBits specifying usage behavior for the command buffer.

- `pInheritanceInfo` is a pointer to a `VkCommandBufferInheritanceInfo` structure, used if `commandBuffer` is a secondary command buffer. If this is a primary command buffer, then this value is ignored.

Valid Usage

- If `flags` contains `VK_COMMAND_BUFFER_USAGE_RENDER_PASS_CONTINUE_BIT`, the `renderPass` member of `pInheritanceInfo` must be a valid `VkRenderPass`

- If `flags` contains `VK_COMMAND_BUFFER_USAGE_RENDER_PASS_CONTINUE_BIT`, the `subpass` member of `pInheritanceInfo` must be a valid subpass index within the `renderPass` member of `pInheritanceInfo`

- If `flags` contains `VK_COMMAND_BUFFER_USAGE_RENDER_PASS_CONTINUE_BIT`, the `framebuffer` member of `pInheritanceInfo` must be either VK_NULL_HANDLE, or a valid `VkFramebuffer` that is compatible with the `renderPass` member of `pInheritanceInfo`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO`

- `pNext` must be `NULL` or a pointer to a valid instance of VkDeviceGroupCommandBufferBeginInfo

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be a valid combination of VkCommandBufferUsageFlagBits values

Bits which can be set in VkCommandBufferBeginInfo::`flags` to specify usage behavior for a command buffer are:

    typedef enum VkCommandBufferUsageFlagBits {
        VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT = 0x00000001,
        VK_COMMAND_BUFFER_USAGE_RENDER_PASS_CONTINUE_BIT = 0x00000002,
        VK_COMMAND_BUFFER_USAGE_SIMULTANEOUS_USE_BIT = 0x00000004,
        VK_COMMAND_BUFFER_USAGE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkCommandBufferUsageFlagBits;

- `VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT` specifies that each recording of the command buffer will only be submitted once, and the command buffer will be reset and recorded again between each submission.

- `VK_COMMAND_BUFFER_USAGE_RENDER_PASS_CONTINUE_BIT` specifies that a secondary command buffer is considered to be entirely inside a render pass. If this is a primary command buffer, then this bit is ignored.

- `VK_COMMAND_BUFFER_USAGE_SIMULTANEOUS_USE_BIT` specifies that a command buffer can be resubmitted to a queue while it is in the pending state, and recorded into multiple primary command buffers.

    typedef VkFlags VkCommandBufferUsageFlags;

`VkCommandBufferUsageFlags` is a bitmask type for setting a mask of zero or more VkCommandBufferUsageFlagBits.

If the command buffer is a secondary command buffer, then the `VkCommandBufferInheritanceInfo` structure defines any state that will be inherited from the primary command buffer:

    typedef struct VkCommandBufferInheritanceInfo {
        VkStructureType                  sType;
        const void*                      pNext;
        VkRenderPass                     renderPass;
        uint32_t                         subpass;
        VkFramebuffer                    framebuffer;
        VkBool32                         occlusionQueryEnable;
        VkQueryControlFlags              queryFlags;
        VkQueryPipelineStatisticFlags    pipelineStatistics;
    } VkCommandBufferInheritanceInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `renderPass` is a VkRenderPass object defining which render passes the `VkCommandBuffer` will be compatible with and can be executed within. If the `VkCommandBuffer` will not be executed within a render pass instance, `renderPass` is ignored.

- `subpass` is the index of the subpass within the render pass instance that the `VkCommandBuffer` will be executed within. If the `VkCommandBuffer` will not be executed within a render pass instance, `subpass` is ignored.

- `framebuffer` optionally refers to the VkFramebuffer object that the `VkCommandBuffer` will be rendering to if it is executed within a render pass instance. It can be VK_NULL_HANDLE if the framebuffer is not known, or if the `VkCommandBuffer` will not be executed within a render pass instance.

  | Note Specifying the exact framebuffer that the secondary command buffer will be executed with may result in better performance at command buffer execution time.

- `occlusionQueryEnable` specifies whether the command buffer can be executed while an occlusion query is active in the primary command buffer. If this is `VK_TRUE`, then this command buffer can be executed whether the primary command buffer has an occlusion query active or not. If this is `VK_FALSE`, then the primary command buffer must not have an occlusion query active.

- `queryFlags` specifies the query flags that can be used by an active occlusion query in the primary command buffer when this secondary command buffer is executed. If this value includes the `VK_QUERY_CONTROL_PRECISE_BIT` bit, then the active query can return boolean results or actual sample counts. If this bit is not set, then the active query must not use the `VK_QUERY_CONTROL_PRECISE_BIT` bit.

- `pipelineStatistics` is a bitmask of VkQueryPipelineStatisticFlagBits specifying the set of pipeline statistics that can be counted by an active query in the primary command buffer when this secondary command buffer is executed. If this value includes a given bit, then this command buffer can be executed whether the primary command buffer has a pipeline statistics query active that includes this bit or not. If this value excludes a given bit, then the active pipeline statistics query must not be from a query pool that counts that statistic.

Valid Usage

- If the inherited queries feature is not enabled, `occlusionQueryEnable` must be `VK_FALSE`

- If the inherited queries feature is enabled, `queryFlags` must be a valid combination of VkQueryControlFlagBits values

- If the inherited queries feature is not enabled, `queryFlags` must be `0`

- If the pipeline statistics queries feature is enabled, `pipelineStatistics` must be a valid combination of VkQueryPipelineStatisticFlagBits values

- If the pipeline statistics queries feature is not enabled, `pipelineStatistics` must be `0`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_COMMAND_BUFFER_INHERITANCE_INFO`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkCommandBufferInheritanceConditionalRenderingInfoEXT or VkCommandBufferInheritanceRenderPassTransformInfoQCOM

- The `sType` value of each struct in the `pNext` chain must be unique

- Both of `framebuffer`, and `renderPass` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

| Note On some implementations, not using the `VK_COMMAND_BUFFER_USAGE_SIMULTANEOUS_USE_BIT` bit enables command buffers to be patched in-place if needed, rather than creating a copy of the command buffer.

If a command buffer is in the invalid, or executable state, and the command buffer was allocated from a command pool with the `VK_COMMAND_POOL_CREATE_RESET_COMMAND_BUFFER_BIT` flag set, then `vkBeginCommandBuffer` implicitly resets the command buffer, behaving as if `vkResetCommandBuffer` had been called with `VK_COMMAND_BUFFER_RESET_RELEASE_RESOURCES_BIT` not set. After the implicit reset, `commandBuffer` is moved to the recording state.

If the `pNext` chain of VkCommandBufferInheritanceInfo includes a `VkCommandBufferInheritanceConditionalRenderingInfoEXT` structure, then that structure controls whether a command buffer can be executed while conditional rendering is active in the primary command buffer.

The `VkCommandBufferInheritanceConditionalRenderingInfoEXT` structure is defined as:

    typedef struct VkCommandBufferInheritanceConditionalRenderingInfoEXT {
        VkStructureType    sType;
        const void*        pNext;
        VkBool32           conditionalRenderingEnable;
    } VkCommandBufferInheritanceConditionalRenderingInfoEXT;

- `sType` is the type of this structure

- `pNext` is `NULL` or a pointer to an extension-specific structure

- `conditionalRenderingEnable` specifies whether the command buffer can be executed while conditional rendering is active in the primary command buffer. If this is `VK_TRUE`, then this command buffer can be executed whether the primary command buffer has active conditional rendering or not. If this is `VK_FALSE`, then the primary command buffer must not have conditional rendering active.

If this structure is not present, the behavior is as if `conditionalRenderingEnable` is `VK_FALSE`.

Valid Usage

- If the inherited conditional rendering feature is not enabled, `conditionalRenderingEnable` must be `VK_FALSE`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_COMMAND_BUFFER_INHERITANCE_CONDITIONAL_RENDERING_INFO_EXT`

To begin recording a secondary command buffer compatible with execution inside a render pass using render pass transform, add the VkCommandBufferInheritanceRenderPassTransformInfoQCOM to the `pNext` chain of VkCommandBufferInheritanceInfo structure passed to the vkBeginCommandBuffer command specifying the parameters for transformed rasterization.

The `VkCommandBufferInheritanceRenderPassTransformInfoQCOM` structure is defined as:

    typedef struct VkCommandBufferInheritanceRenderPassTransformInfoQCOM {
        VkStructureType                  sType;
        void*                            pNext;
        VkSurfaceTransformFlagBitsKHR    transform;
        VkRect2D                         renderArea;
    } VkCommandBufferInheritanceRenderPassTransformInfoQCOM;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `transform` is a VkSurfaceTransformFlagBitsKHR value describing the transform to be applied applied to the render pass.

- `renderArea` is the render area that is affected by the command buffer.

When the secondary is recorded to execute within a render pass instance using vkCmdExecuteCommands, the render pass transform parameters of the secondary command buffer must be consistent with the render pass transform parameters specified for the render pass instance. In particular, the `transform` and `renderArea` for command buffer must be identical to the `transform` and `renderArea` of the render pass instance.

Valid Usage

- `transform` must be VK_SURFACE_TRANSFORM_IDENTITY_BIT_KHR, VK_SURFACE_TRANSFORM_ROTATE_90_BIT_KHR, VK_SURFACE_TRANSFORM_ROTATE_180_BIT_KHR, or VK_SURFACE_TRANSFORM_ROTATE_270_BIT_KHR.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_COMMAND_BUFFER_INHERITANCE_RENDER_PASS_TRANSFORM_INFO_QCOM`

Once recording starts, an application records a sequence of commands (`vkCmd*`) to set state in the command buffer, draw, dispatch, and other commands.

Several commands can also be recorded indirectly from `VkBuffer` content, see Device-Generated Commands.

To complete recording of a command buffer, call:

    VkResult vkEndCommandBuffer(
        VkCommandBuffer                             commandBuffer);

- `commandBuffer` is the command buffer to complete recording.

If there was an error during recording, the application will be notified by an unsuccessful return code returned by `vkEndCommandBuffer`. If the application wishes to further use the command buffer, the command buffer must be reset. The command buffer must have been in the recording state, and is moved to the executable state.

Valid Usage

- `commandBuffer` must be in the recording state.

- If `commandBuffer` is a primary command buffer, there must not be an active render pass instance

- All queries made active during the recording of `commandBuffer` must have been made inactive

- Conditional rendering must not be active

- If `commandBuffer` is a secondary command buffer, there must not be an outstanding vkCmdBeginDebugUtilsLabelEXT command recorded to `commandBuffer` that has not previously been ended by a call to vkCmdEndDebugUtilsLabelEXT.

- If `commandBuffer` is a secondary command buffer, there must not be an outstanding vkCmdDebugMarkerBeginEXT command recorded to `commandBuffer` that has not previously been ended by a call to vkCmdDebugMarkerEndEXT.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

When a command buffer is in the executable state, it can be submitted to a queue for execution.

### 5.5. Command Buffer Submission

To submit command buffers to a queue, call:

    VkResult vkQueueSubmit(
        VkQueue                                     queue,
        uint32_t                                    submitCount,
        const VkSubmitInfo*                         pSubmits,
        VkFence                                     fence);

- `queue` is the queue that the command buffers will be submitted to.

- `submitCount` is the number of elements in the `pSubmits` array.

- `pSubmits` is a pointer to an array of VkSubmitInfo structures, each specifying a command buffer submission batch.

- `fence` is an optional handle to a fence to be signaled once all submitted command buffers have completed execution. If `fence` is not VK_NULL_HANDLE, it defines a fence signal operation.

| Note Submission can be a high overhead operation, and applications should attempt to batch work together into as few calls to `vkQueueSubmit` as possible.

`vkQueueSubmit` is a queue submission command, with each batch defined by an element of `pSubmits`. Batches begin execution in the order they appear in `pSubmits`, but may complete out of order.

Fence and semaphore operations submitted with vkQueueSubmit have additional ordering constraints compared to other submission commands, with dependencies involving previous and subsequent queue operations. Information about these additional constraints can be found in the semaphore and fence sections of the synchronization chapter.

Details on the interaction of `pWaitDstStageMask` with synchronization are described in the semaphore wait operation section of the synchronization chapter.

The order that batches appear in `pSubmits` is used to determine submission order, and thus all the implicit ordering guarantees that respect it. Other than these implicit ordering guarantees and any explicit synchronization primitives, these batches may overlap or otherwise execute out of order.

If any command buffer submitted to this queue is in the executable state, it is moved to the pending state. Once execution of all submissions of a command buffer complete, it moves from the pending state, back to the executable state. If a command buffer was recorded with the `VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT` flag, it instead moves to the invalid state.

If `vkQueueSubmit` fails, it may return `VK_ERROR_OUT_OF_HOST_MEMORY` or `VK_ERROR_OUT_OF_DEVICE_MEMORY`. If it does, the implementation must ensure that the state and contents of any resources or synchronization primitives referenced by the submitted command buffers and any semaphores referenced by `pSubmits` is unaffected by the call or its failure. If `vkQueueSubmit` fails in such a way that the implementation is unable to make that guarantee, the implementation must return `VK_ERROR_DEVICE_LOST`. See Lost Device.

Valid Usage

- If `fence` is not VK_NULL_HANDLE, `fence` must be unsignaled

- If `fence` is not VK_NULL_HANDLE, `fence` must not be associated with any other queue command that has not yet completed execution on that queue

- Any calls to vkCmdSetEvent, vkCmdResetEvent or vkCmdWaitEvents that have been recorded into any of the command buffer elements of the `pCommandBuffers` member of any element of `pSubmits`, must not reference any VkEvent that is referenced by any of those commands in a command buffer that has been submitted to another queue and is still in the pending state

- Any stage flag included in any element of the `pWaitDstStageMask` member of any element of `pSubmits` must be a pipeline stage supported by one of the capabilities of `queue`, as specified in the table of supported pipeline stages

- Each element of the `pSignalSemaphores` member of any element of `pSubmits` must be unsignaled when the semaphore signal operation it defines is executed on the device

- When a semaphore wait operation referring to a binary semaphore defined by any element of the `pWaitSemaphores` member of any element of `pSubmits` executes on `queue`, there must be no other queues waiting on the same semaphore

- All elements of the `pWaitSemaphores` member of all elements of `pSubmits` created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_BINARY` must reference a semaphore signal operation that has been submitted for execution and any semaphore signal operations on which it depends (if any) must have also been submitted for execution

- Each element of the `pCommandBuffers` member of each element of `pSubmits` must be in the pending or executable state

- If any element of the `pCommandBuffers` member of any element of `pSubmits` was not recorded with the `VK_COMMAND_BUFFER_USAGE_SIMULTANEOUS_USE_BIT`, it must not be in the pending state

- Any secondary command buffers recorded into any element of the `pCommandBuffers` member of any element of `pSubmits` must be in the pending or executable state

- If any secondary command buffers recorded into any element of the `pCommandBuffers` member of any element of `pSubmits` was not recorded with the `VK_COMMAND_BUFFER_USAGE_SIMULTANEOUS_USE_BIT`, it must not be in the pending state

- Each element of the `pCommandBuffers` member of each element of `pSubmits` must have been allocated from a `VkCommandPool` that was created for the same queue family `queue` belongs to

- If any element of `pSubmits->pCommandBuffers` includes a Queue Family Transfer Acquire Operation, there must exist a previously submitted Queue Family Transfer Release Operation on a queue in the queue family identified by the acquire operation, with parameters matching the acquire operation as defined in the definition of such acquire operations, and which happens-before the acquire operation

- If a command recorded into any element of `pCommandBuffers` was a vkCmdBeginQuery whose `queryPool` was created with a `queryType` of `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR`, the profiling lock must have been held continuously on the `VkDevice` that `queue` was retrieved from, throughout recording of those command buffers

- Any resource created with `VK_SHARING_MODE_EXCLUSIVE` that is read by an operation specified by `pSubmits` must not be owned by any queue family other than the one which `queue` belongs to, at the time it is executed

Valid Usage (Implicit)

- `queue` must be a valid VkQueue handle

- If `submitCount` is not `0`, `pSubmits` must be a valid pointer to an array of `submitCount` valid VkSubmitInfo structures

- If `fence` is not VK_NULL_HANDLE, `fence` must be a valid VkFence handle

- Both of `fence`, and `queue` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `queue` must be externally synchronized

- Host access to `fence` must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
- | - | Any | -

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_DEVICE_LOST`

The `VkSubmitInfo` structure is defined as:

    typedef struct VkSubmitInfo {
        VkStructureType                sType;
        const void*                    pNext;
        uint32_t                       waitSemaphoreCount;
        const VkSemaphore*             pWaitSemaphores;
        const VkPipelineStageFlags*    pWaitDstStageMask;
        uint32_t                       commandBufferCount;
        const VkCommandBuffer*         pCommandBuffers;
        uint32_t                       signalSemaphoreCount;
        const VkSemaphore*             pSignalSemaphores;
    } VkSubmitInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `waitSemaphoreCount` is the number of semaphores upon which to wait before executing the command buffers for the batch.

- `pWaitSemaphores` is a pointer to an array of VkSemaphore handles upon which to wait before the command buffers for this batch begin execution. If semaphores to wait on are provided, they define a semaphore wait operation.

- `pWaitDstStageMask` is a pointer to an array of pipeline stages at which each corresponding semaphore wait will occur.

- `commandBufferCount` is the number of command buffers to execute in the batch.

- `pCommandBuffers` is a pointer to an array of VkCommandBuffer handles to execute in the batch.

- `signalSemaphoreCount` is the number of semaphores to be signaled once the commands specified in `pCommandBuffers` have completed execution.

- `pSignalSemaphores` is a pointer to an array of VkSemaphore handles which will be signaled when the command buffers for this batch have completed execution. If semaphores to be signaled are provided, they define a semaphore signal operation.

The order that command buffers appear in `pCommandBuffers` is used to determine submission order, and thus all the implicit ordering guarantees that respect it. Other than these implicit ordering guarantees and any explicit synchronization primitives, these command buffers may overlap or otherwise execute out of order.

Valid Usage

- Each element of `pCommandBuffers` must not have been allocated with `VK_COMMAND_BUFFER_LEVEL_SECONDARY`

- If the geometry shaders feature is not enabled, each element of `pWaitDstStageMask` must not contain `VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT`

- If the tessellation shaders feature is not enabled, each element of `pWaitDstStageMask` must not contain `VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT` or `VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT`

- Each element of `pWaitDstStageMask` must not include `VK_PIPELINE_STAGE_HOST_BIT`.

- If any element of `pWaitSemaphores` or `pSignalSemaphores` was created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE`, then the `pNext` chain must include a VkTimelineSemaphoreSubmitInfo structure

- If the `pNext` chain of this structure includes a VkTimelineSemaphoreSubmitInfo structure and any element of `pWaitSemaphores` was created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE`, then its `waitSemaphoreValueCount` member must equal `waitSemaphoreCount`

- If the `pNext` chain of this structure includes a VkTimelineSemaphoreSubmitInfo structure and any element of `pSignalSemaphores` was created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE`, then its `signalSemaphoreValueCount` member must equal `signalSemaphoreCount`

- For each element of `pSignalSemaphores` created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE` the corresponding element of VkTimelineSemaphoreSubmitInfo::pSignalSemaphoreValues must have a value greater than the current value of the semaphore when the semaphore signal operation is executed

- For each element of `pWaitSemaphores` created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE` the corresponding element of VkTimelineSemaphoreSubmitInfo::pWaitSemaphoreValues must have a value which does not differ from the current value of the semaphore or the value of any outstanding semaphore wait or signal operation on that semaphore by more than `maxTimelineSemaphoreValueDifference`.

- For each element of `pSignalSemaphores` created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE` the corresponding element of VkTimelineSemaphoreSubmitInfo::pSignalSemaphoreValues must have a value which does not differ from the current value of the semaphore or the value of any outstanding semaphore wait or signal operation on that semaphore by more than `maxTimelineSemaphoreValueDifference`.

- If the mesh shaders feature is not enabled, each element of `pWaitDstStageMask` must not contain `VK_PIPELINE_STAGE_MESH_SHADER_BIT_NV`

- If the task shaders feature is not enabled, each element of `pWaitDstStageMask` must not contain `VK_PIPELINE_STAGE_TASK_SHADER_BIT_NV`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SUBMIT_INFO`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkD3D12FenceSubmitInfoKHR, VkDeviceGroupSubmitInfo, VkPerformanceQuerySubmitInfoKHR, VkProtectedSubmitInfo, VkTimelineSemaphoreSubmitInfo, VkWin32KeyedMutexAcquireReleaseInfoKHR, or VkWin32KeyedMutexAcquireReleaseInfoNV

- The `sType` value of each struct in the `pNext` chain must be unique

- If `waitSemaphoreCount` is not `0`, `pWaitSemaphores` must be a valid pointer to an array of `waitSemaphoreCount` valid VkSemaphore handles

- If `waitSemaphoreCount` is not `0`, `pWaitDstStageMask` must be a valid pointer to an array of `waitSemaphoreCount` valid combinations of VkPipelineStageFlagBits values

- Each element of `pWaitDstStageMask` must not be `0`

- If `commandBufferCount` is not `0`, `pCommandBuffers` must be a valid pointer to an array of `commandBufferCount` valid VkCommandBuffer handles

- If `signalSemaphoreCount` is not `0`, `pSignalSemaphores` must be a valid pointer to an array of `signalSemaphoreCount` valid VkSemaphore handles

- Each of the elements of `pCommandBuffers`, the elements of `pSignalSemaphores`, and the elements of `pWaitSemaphores` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

To specify the values to use when waiting for and signaling semaphores created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE`, add a VkTimelineSemaphoreSubmitInfo structure to the `pNext` chain of the VkSubmitInfo structure when using vkQueueSubmit or the VkBindSparseInfo structure when using vkQueueBindSparse. The `VkTimelineSemaphoreSubmitInfo` structure is defined as:

    typedef struct VkTimelineSemaphoreSubmitInfo {
        VkStructureType    sType;
        const void*        pNext;
        uint32_t           waitSemaphoreValueCount;
        const uint64_t*    pWaitSemaphoreValues;
        uint32_t           signalSemaphoreValueCount;
        const uint64_t*    pSignalSemaphoreValues;
    } VkTimelineSemaphoreSubmitInfo;

or the equivalent

    typedef VkTimelineSemaphoreSubmitInfo VkTimelineSemaphoreSubmitInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `waitSemaphoreValueCount` is the number of semaphore wait values specified in `pWaitSemaphoreValues`.

- `pWaitSemaphoreValues` is an array of length `waitSemaphoreValueCount` containing values for the corresponding semaphores in VkSubmitInfo::`pWaitSemaphores` to wait for.

- `signalSemaphoreValueCount` is the number of semaphore signal values specified in `pSignalSemaphoreValues`.

- `pSignalSemaphoreValues` is an array of length `signalSemaphoreValueCount` containing values for the corresponding semaphores in VkSubmitInfo::`pSignalSemaphores` to set when signaled.

If the semaphore in VkSubmitInfo::`pWaitSemaphores` or VkSubmitInfo::`pSignalSemaphores` corresponding to an entry in `pWaitSemaphoreValues` or `pSignalSemaphoreValues` respectively was not created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE`, the implementation must ignore the value in the `pWaitSemaphoreValues` or `pSignalSemaphoreValues` entry.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_TIMELINE_SEMAPHORE_SUBMIT_INFO`

- If `waitSemaphoreValueCount` is not `0`, and `pWaitSemaphoreValues` is not `NULL`, `pWaitSemaphoreValues` must be a valid pointer to an array of `waitSemaphoreValueCount` `uint64_t` values

- If `signalSemaphoreValueCount` is not `0`, and `pSignalSemaphoreValues` is not `NULL`, `pSignalSemaphoreValues` must be a valid pointer to an array of `signalSemaphoreValueCount` `uint64_t` values

To specify the values to use when waiting for and signaling semaphores whose current payload refers to a Direct3D 12 fence, add a VkD3D12FenceSubmitInfoKHR structure to the `pNext` chain of the VkSubmitInfo structure. The `VkD3D12FenceSubmitInfoKHR` structure is defined as:

    typedef struct VkD3D12FenceSubmitInfoKHR {
        VkStructureType    sType;
        const void*        pNext;
        uint32_t           waitSemaphoreValuesCount;
        const uint64_t*    pWaitSemaphoreValues;
        uint32_t           signalSemaphoreValuesCount;
        const uint64_t*    pSignalSemaphoreValues;
    } VkD3D12FenceSubmitInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `waitSemaphoreValuesCount` is the number of semaphore wait values specified in `pWaitSemaphoreValues`.

- `pWaitSemaphoreValues` is a pointer to an array of `waitSemaphoreValuesCount` values for the corresponding semaphores in VkSubmitInfo::`pWaitSemaphores` to wait for.

- `signalSemaphoreValuesCount` is the number of semaphore signal values specified in `pSignalSemaphoreValues`.

- `pSignalSemaphoreValues` is a pointer to an array of `signalSemaphoreValuesCount` values for the corresponding semaphores in VkSubmitInfo::`pSignalSemaphores` to set when signaled.

If the semaphore in VkSubmitInfo::`pWaitSemaphores` or VkSubmitInfo::`pSignalSemaphores` corresponding to an entry in `pWaitSemaphoreValues` or `pSignalSemaphoreValues` respectively does not currently have a payload referring to a Direct3D 12 fence, the implementation must ignore the value in the `pWaitSemaphoreValues` or `pSignalSemaphoreValues` entry.

| Note As the introduction of the external semaphore handle type `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D12_FENCE_BIT` predates that of timeline semaphores, support for importing semaphore payloads from external handles of that type into semaphores created (implicitly or explicitly) with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_BINARY` is preserved for backwards compatibility. However, applications should prefer importing such handle types into semaphores created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE`, and use the VkTimelineSemaphoreSubmitInfo structure instead of the `VkD3D12FenceSubmitInfoKHR` structure to specify the values to use when waiting for and signaling such semaphores.

Valid Usage

- `waitSemaphoreValuesCount` must be the same value as `VkSubmitInfo`::`waitSemaphoreCount`, where `VkSubmitInfo` is in the `pNext` chain of this `VkD3D12FenceSubmitInfoKHR` structure.

- `signalSemaphoreValuesCount` must be the same value as `VkSubmitInfo`::`signalSemaphoreCount`, where `VkSubmitInfo` is in the `pNext` chain of this `VkD3D12FenceSubmitInfoKHR` structure.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_D3D12_FENCE_SUBMIT_INFO_KHR`

- If `waitSemaphoreValuesCount` is not `0`, and `pWaitSemaphoreValues` is not `NULL`, `pWaitSemaphoreValues` must be a valid pointer to an array of `waitSemaphoreValuesCount` `uint64_t` values

- If `signalSemaphoreValuesCount` is not `0`, and `pSignalSemaphoreValues` is not `NULL`, `pSignalSemaphoreValues` must be a valid pointer to an array of `signalSemaphoreValuesCount` `uint64_t` values

When submitting work that operates on memory imported from a Direct3D 11 resource to a queue, the keyed mutex mechanism may be used in addition to Vulkan semaphores to synchronize the work. Keyed mutexes are a property of a properly created shareable Direct3D 11 resource. They can only be used if the imported resource was created with the `D3D11_RESOURCE_MISC_SHARED_KEYEDMUTEX` flag.

To acquire keyed mutexes before submitted work and/or release them after, add a VkWin32KeyedMutexAcquireReleaseInfoKHR structure to the `pNext` chain of the VkSubmitInfo structure.

The `VkWin32KeyedMutexAcquireReleaseInfoKHR` structure is defined as:

    typedef struct VkWin32KeyedMutexAcquireReleaseInfoKHR {
        VkStructureType          sType;
        const void*              pNext;
        uint32_t                 acquireCount;
        const VkDeviceMemory*    pAcquireSyncs;
        const uint64_t*          pAcquireKeys;
        const uint32_t*          pAcquireTimeouts;
        uint32_t                 releaseCount;
        const VkDeviceMemory*    pReleaseSyncs;
        const uint64_t*          pReleaseKeys;
    } VkWin32KeyedMutexAcquireReleaseInfoKHR;

- `acquireCount` is the number of entries in the `pAcquireSyncs`, `pAcquireKeys`, and `pAcquireTimeoutMilliseconds` arrays.

- `pAcquireSyncs` is a pointer to an array of VkDeviceMemory objects which were imported from Direct3D 11 resources.

- `pAcquireKeys` is a pointer to an array of mutex key values to wait for prior to beginning the submitted work. Entries refer to the keyed mutex associated with the corresponding entries in `pAcquireSyncs`.

- `pAcquireTimeoutMilliseconds` is a pointer to an array of timeout values, in millisecond units, for each acquire specified in `pAcquireKeys`.

- `releaseCount` is the number of entries in the `pReleaseSyncs` and `pReleaseKeys` arrays.

- `pReleaseSyncs` is a pointer to an array of VkDeviceMemory objects which were imported from Direct3D 11 resources.

- `pReleaseKeys` is a pointer to an array of mutex key values to set when the submitted work has completed. Entries refer to the keyed mutex associated with the corresponding entries in `pReleaseSyncs`.

Valid Usage

- Each member of `pAcquireSyncs` and `pReleaseSyncs` must be a device memory object imported by setting VkImportMemoryWin32HandleInfoKHR::`handleType` to `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_BIT` or `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_KMT_BIT`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_WIN32_KEYED_MUTEX_ACQUIRE_RELEASE_INFO_KHR`

- If `acquireCount` is not `0`, `pAcquireSyncs` must be a valid pointer to an array of `acquireCount` valid VkDeviceMemory handles

- If `acquireCount` is not `0`, `pAcquireKeys` must be a valid pointer to an array of `acquireCount` `uint64_t` values

- If `acquireCount` is not `0`, `pAcquireTimeouts` must be a valid pointer to an array of `acquireCount` `uint32_t` values

- If `releaseCount` is not `0`, `pReleaseSyncs` must be a valid pointer to an array of `releaseCount` valid VkDeviceMemory handles

- If `releaseCount` is not `0`, `pReleaseKeys` must be a valid pointer to an array of `releaseCount` `uint64_t` values

- Both of the elements of `pAcquireSyncs`, and the elements of `pReleaseSyncs` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

When submitting work that operates on memory imported from a Direct3D 11 resource to a queue, the keyed mutex mechanism may be used in addition to Vulkan semaphores to synchronize the work. Keyed mutexes are a property of a properly created shareable Direct3D 11 resource. They can only be used if the imported resource was created with the `D3D11_RESOURCE_MISC_SHARED_KEYEDMUTEX` flag.

To acquire keyed mutexes before submitted work and/or release them after, add a VkWin32KeyedMutexAcquireReleaseInfoNV structure to the `pNext` chain of the VkSubmitInfo structure.

The `VkWin32KeyedMutexAcquireReleaseInfoNV` structure is defined as:

    typedef struct VkWin32KeyedMutexAcquireReleaseInfoNV {
        VkStructureType          sType;
        const void*              pNext;
        uint32_t                 acquireCount;
        const VkDeviceMemory*    pAcquireSyncs;
        const uint64_t*          pAcquireKeys;
        const uint32_t*          pAcquireTimeoutMilliseconds;
        uint32_t                 releaseCount;
        const VkDeviceMemory*    pReleaseSyncs;
        const uint64_t*          pReleaseKeys;
    } VkWin32KeyedMutexAcquireReleaseInfoNV;

- `acquireCount` is the number of entries in the `pAcquireSyncs`, `pAcquireKeys`, and `pAcquireTimeoutMilliseconds` arrays.

- `pAcquireSyncs` is a pointer to an array of VkDeviceMemory objects which were imported from Direct3D 11 resources.

- `pAcquireKeys` is a pointer to an array of mutex key values to wait for prior to beginning the submitted work. Entries refer to the keyed mutex associated with the corresponding entries in `pAcquireSyncs`.

- `pAcquireTimeoutMilliseconds` is a pointer to an array of timeout values, in millisecond units, for each acquire specified in `pAcquireKeys`.

- `releaseCount` is the number of entries in the `pReleaseSyncs` and `pReleaseKeys` arrays.

- `pReleaseSyncs` is a pointer to an array of VkDeviceMemory objects which were imported from Direct3D 11 resources.

- `pReleaseKeys` is a pointer to an array of mutex key values to set when the submitted work has completed. Entries refer to the keyed mutex associated with the corresponding entries in `pReleaseSyncs`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_WIN32_KEYED_MUTEX_ACQUIRE_RELEASE_INFO_NV`

- If `acquireCount` is not `0`, `pAcquireSyncs` must be a valid pointer to an array of `acquireCount` valid VkDeviceMemory handles

- If `acquireCount` is not `0`, `pAcquireKeys` must be a valid pointer to an array of `acquireCount` `uint64_t` values

- If `acquireCount` is not `0`, `pAcquireTimeoutMilliseconds` must be a valid pointer to an array of `acquireCount` `uint32_t` values

- If `releaseCount` is not `0`, `pReleaseSyncs` must be a valid pointer to an array of `releaseCount` valid VkDeviceMemory handles

- If `releaseCount` is not `0`, `pReleaseKeys` must be a valid pointer to an array of `releaseCount` `uint64_t` values

- Both of the elements of `pAcquireSyncs`, and the elements of `pReleaseSyncs` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

If the `pNext` chain of VkSubmitInfo includes a `VkProtectedSubmitInfo` structure, then the structure indicates whether the batch is protected. The `VkProtectedSubmitInfo` structure is defined as:

    typedef struct VkProtectedSubmitInfo {
        VkStructureType    sType;
        const void*        pNext;
        VkBool32           protectedSubmit;
    } VkProtectedSubmitInfo;

- `protectedSubmit` specifies whether the batch is protected. If `protectedSubmit` is `VK_TRUE`, the batch is protected. If `protectedSubmit` is `VK_FALSE`, the batch is unprotected. If the `VkSubmitInfo`::`pNext` chain does not include this structure, the batch is unprotected.

Valid Usage

- If the protected memory feature is not enabled, `protectedSubmit` must not be `VK_TRUE`.

- If `protectedSubmit` is `VK_TRUE`, then each element of the `pCommandBuffers` array must be a protected command buffer.

- If `protectedSubmit` is `VK_FALSE`, then each element of the `pCommandBuffers` array must be an unprotected command buffer.

- If the `VkSubmitInfo`::`pNext` chain does not include a `VkProtectedSubmitInfo` structure, then each element of the command buffer of the `pCommandBuffers` array must be an unprotected command buffer.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PROTECTED_SUBMIT_INFO`

If the `pNext` chain of VkSubmitInfo includes a `VkDeviceGroupSubmitInfo` structure, then that structure includes device indices and masks specifying which physical devices execute semaphore operations and command buffers.

The `VkDeviceGroupSubmitInfo` structure is defined as:

    typedef struct VkDeviceGroupSubmitInfo {
        VkStructureType    sType;
        const void*        pNext;
        uint32_t           waitSemaphoreCount;
        const uint32_t*    pWaitSemaphoreDeviceIndices;
        uint32_t           commandBufferCount;
        const uint32_t*    pCommandBufferDeviceMasks;
        uint32_t           signalSemaphoreCount;
        const uint32_t*    pSignalSemaphoreDeviceIndices;
    } VkDeviceGroupSubmitInfo;

or the equivalent

    typedef VkDeviceGroupSubmitInfo VkDeviceGroupSubmitInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `waitSemaphoreCount` is the number of elements in the `pWaitSemaphoreDeviceIndices` array.

- `pWaitSemaphoreDeviceIndices` is a pointer to an array of `waitSemaphoreCount` device indices indicating which physical device executes the semaphore wait operation in the corresponding element of VkSubmitInfo::`pWaitSemaphores`.

- `commandBufferCount` is the number of elements in the `pCommandBufferDeviceMasks` array.

- `pCommandBufferDeviceMasks` is a pointer to an array of `commandBufferCount` device masks indicating which physical devices execute the command buffer in the corresponding element of VkSubmitInfo::`pCommandBuffers`. A physical device executes the command buffer if the corresponding bit is set in the mask.

- `signalSemaphoreCount` is the number of elements in the `pSignalSemaphoreDeviceIndices` array.

- `pSignalSemaphoreDeviceIndices` is a pointer to an array of `signalSemaphoreCount` device indices indicating which physical device executes the semaphore signal operation in the corresponding element of VkSubmitInfo::`pSignalSemaphores`.

If this structure is not present, semaphore operations and command buffers execute on device index zero.

Valid Usage

- `waitSemaphoreCount` must equal VkSubmitInfo::`waitSemaphoreCount`

- `commandBufferCount` must equal VkSubmitInfo::`commandBufferCount`

- `signalSemaphoreCount` must equal VkSubmitInfo::`signalSemaphoreCount`

- All elements of `pWaitSemaphoreDeviceIndices` and `pSignalSemaphoreDeviceIndices` must be valid device indices

- All elements of `pCommandBufferDeviceMasks` must be valid device masks

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEVICE_GROUP_SUBMIT_INFO`

- If `waitSemaphoreCount` is not `0`, `pWaitSemaphoreDeviceIndices` must be a valid pointer to an array of `waitSemaphoreCount` `uint32_t` values

- If `commandBufferCount` is not `0`, `pCommandBufferDeviceMasks` must be a valid pointer to an array of `commandBufferCount` `uint32_t` values

- If `signalSemaphoreCount` is not `0`, `pSignalSemaphoreDeviceIndices` must be a valid pointer to an array of `signalSemaphoreCount` `uint32_t` values

If the `pNext` chain of VkSubmitInfo includes a VkPerformanceQuerySubmitInfoKHR structure, then the structure indicates which counter pass is active for the batch in that submit.

The `VkPerformanceQuerySubmitInfoKHR` structure is defined as:

    typedef struct VkPerformanceQuerySubmitInfoKHR {
        VkStructureType    sType;
        const void*        pNext;
        uint32_t           counterPassIndex;
    } VkPerformanceQuerySubmitInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `counterPassIndex` specifies which counter pass index is active.

If the `VkSubmitInfo`::`pNext` chain does not include this structure, the batch defaults to use counter pass index 0.

Valid Usage

- `counterPassIndex` must be less than the number of counter passes required by any queries within the batch. The required number of counter passes for a performance query is obtained by calling vkGetPhysicalDeviceQueueFamilyPerformanceQueryPassesKHR

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PERFORMANCE_QUERY_SUBMIT_INFO_KHR`

### 5.6. Queue Forward Progress

When using binary semaphores, the application must ensure that command buffer submissions will be able to complete without any subsequent operations by the application on any queue. After any call to `vkQueueSubmit` (or other queue operation), for every queued wait on a semaphore created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_BINARY` there must be a prior signal of that semaphore that will not be consumed by a different wait on the semaphore.

When using timeline semaphores, wait-before-signal behavior is well-defined and applications can submit work via `vkQueueSubmit` which defines a timeline semaphore wait operation before submitting a corresponding semaphore signal operation. For each timeline semaphore wait operation defined by a call to `vkQueueSubmit`, the application must ensure that a corresponding semaphore signal operation is executed before forward progress can be made.

Command buffers in the submission can include vkCmdWaitEvents commands that wait on events that will not be signaled by earlier commands in the queue. Such events must be signaled by the application using vkSetEvent, and the `vkCmdWaitEvents` commands that wait upon them must not be inside a render pass instance. The event must be set before the vkCmdWaitEvents command is executed.

| Note Implementations may have some tolerance for waiting on events to be set, but this is defined outside of the scope of Vulkan.

### 5.7. Secondary Command Buffer Execution

A secondary command buffer must not be directly submitted to a queue. Instead, secondary command buffers are recorded to execute as part of a primary command buffer with the command:

    void vkCmdExecuteCommands(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    commandBufferCount,
        const VkCommandBuffer*                      pCommandBuffers);

- `commandBuffer` is a handle to a primary command buffer that the secondary command buffers are executed in.

- `commandBufferCount` is the length of the `pCommandBuffers` array.

- `pCommandBuffers` is a pointer to an array of `commandBufferCount` secondary command buffer handles, which are recorded to execute in the primary command buffer in the order they are listed in the array.

If any element of `pCommandBuffers` was not recorded with the `VK_COMMAND_BUFFER_USAGE_SIMULTANEOUS_USE_BIT` flag, and it was recorded into any other primary command buffer which is currently in the executable or recording state, that primary command buffer becomes invalid.

Valid Usage

- Each element of `pCommandBuffers` must have been allocated with a `level` of `VK_COMMAND_BUFFER_LEVEL_SECONDARY`

- Each element of `pCommandBuffers` must be in the pending or executable state

- If any element of `pCommandBuffers` was not recorded with the `VK_COMMAND_BUFFER_USAGE_SIMULTANEOUS_USE_BIT` flag, it must not be in the pending state

- If any element of `pCommandBuffers` was not recorded with the `VK_COMMAND_BUFFER_USAGE_SIMULTANEOUS_USE_BIT` flag, it must not have already been recorded to `commandBuffer`

- If any element of `pCommandBuffers` was not recorded with the `VK_COMMAND_BUFFER_USAGE_SIMULTANEOUS_USE_BIT` flag, it must not appear more than once in `pCommandBuffers`

- Each element of `pCommandBuffers` must have been allocated from a `VkCommandPool` that was created for the same queue family as the `VkCommandPool` from which `commandBuffer` was allocated

- If `vkCmdExecuteCommands` is being called within a render pass instance, that render pass instance must have been begun with the `contents` parameter of `vkCmdBeginRenderPass` set to `VK_SUBPASS_CONTENTS_SECONDARY_COMMAND_BUFFERS`

- If `vkCmdExecuteCommands` is being called within a render pass instance, each element of `pCommandBuffers` must have been recorded with the `VK_COMMAND_BUFFER_USAGE_RENDER_PASS_CONTINUE_BIT`

- If `vkCmdExecuteCommands` is being called within a render pass instance, each element of `pCommandBuffers` must have been recorded with `VkCommandBufferInheritanceInfo`::`subpass` set to the index of the subpass which the given command buffer will be executed in

- If `vkCmdExecuteCommands` is being called within a render pass instance, the render passes specified in the `pBeginInfo->pInheritanceInfo->renderPass` members of the vkBeginCommandBuffer commands used to begin recording each element of `pCommandBuffers` must be compatible with the current render pass

- If `vkCmdExecuteCommands` is being called within a render pass instance, and any element of `pCommandBuffers` was recorded with VkCommandBufferInheritanceInfo::`framebuffer` not equal to VK_NULL_HANDLE, that `VkFramebuffer` must match the `VkFramebuffer` used in the current render pass instance

- If `vkCmdExecuteCommands` is being called within a render pass instance that included VkRenderPassTransformBeginInfoQCOM in the `pNext` chain of VkRenderPassBeginInfo, then each element of `pCommandBuffers` must have been recorded with VkCommandBufferInheritanceRenderPassTransformInfoQCOM in the `pNext` chain of VkCommandBufferBeginInfo

- If `vkCmdExecuteCommands` is being called within a render pass instance that included VkRenderPassTransformBeginInfoQCOM in the `pNext` chain of VkRenderPassBeginInfo, then each element of `pCommandBuffers` must have been recorded with VkCommandBufferInheritanceRenderPassTransformInfoQCOM::`transform` identical to VkRenderPassTransformBeginInfoQCOM::`transform`

- If `vkCmdExecuteCommands` is being called within a render pass instance that included VkRenderPassTransformBeginInfoQCOM in the `pNext` chain of VkRenderPassBeginInfo, then each element of `pCommandBuffers` must have been recorded with VkCommandBufferInheritanceRenderPassTransformInfoQCOM::`renderArea` identical to VkRenderPassBeginInfo::`renderArea`

- If `vkCmdExecuteCommands` is not being called within a render pass instance, each element of `pCommandBuffers` must not have been recorded with the `VK_COMMAND_BUFFER_USAGE_RENDER_PASS_CONTINUE_BIT`

- If the inherited queries feature is not enabled, `commandBuffer` must not have any queries active

- If `commandBuffer` has a `VK_QUERY_TYPE_OCCLUSION` query active, then each element of `pCommandBuffers` must have been recorded with `VkCommandBufferInheritanceInfo`::`occlusionQueryEnable` set to `VK_TRUE`

- If `commandBuffer` has a `VK_QUERY_TYPE_OCCLUSION` query active, then each element of `pCommandBuffers` must have been recorded with `VkCommandBufferInheritanceInfo`::`queryFlags` having all bits set that are set for the query

- If `commandBuffer` has a `VK_QUERY_TYPE_PIPELINE_STATISTICS` query active, then each element of `pCommandBuffers` must have been recorded with `VkCommandBufferInheritanceInfo`::`pipelineStatistics` having all bits set that are set in the `VkQueryPool` the query uses

- Each element of `pCommandBuffers` must not begin any query types that are active in `commandBuffer`

- If `commandBuffer` is a protected command buffer, then each element of `pCommandBuffers` must be a protected command buffer

- If `commandBuffer` is an unprotected command buffer, then each element of `pCommandBuffers` must be an unprotected command buffer

- This command must not be recorded when transform feedback is active

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pCommandBuffers` must be a valid pointer to an array of `commandBufferCount` valid VkCommandBuffer handles

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support transfer, graphics, or compute operations

- `commandBuffer` must be a primary `VkCommandBuffer`

- `commandBufferCount` must be greater than `0`

- Both of `commandBuffer`, and the elements of `pCommandBuffers` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary | Both | Transfer Graphics Compute |

### 5.8. Command Buffer Device Mask

Each command buffer has a piece of state storing the current device mask of the command buffer. This mask controls which physical devices within the logical device all subsequent commands will execute on, including state-setting commands, action commands, and synchronization commands.

Scissor, exclusive scissor, and viewport state can be set to different values on each physical device (only when set as dynamic state), and each physical device will render using its local copy of the state. Other state is shared between physical devices, such that all physical devices use the most recently set values for the state. However, when recording an action command that uses a piece of state, the most recent command that set that state must have included all physical devices that execute the action command in its current device mask.

The command buffer’s device mask is orthogonal to the `pCommandBufferDeviceMasks` member of VkDeviceGroupSubmitInfo. Commands only execute on a physical device if the device index is set in both device masks.

If the `pNext` chain of VkCommandBufferBeginInfo includes a `VkDeviceGroupCommandBufferBeginInfo` structure, then that structure includes an initial device mask for the command buffer.

The `VkDeviceGroupCommandBufferBeginInfo` structure is defined as:

    typedef struct VkDeviceGroupCommandBufferBeginInfo {
        VkStructureType    sType;
        const void*        pNext;
        uint32_t           deviceMask;
    } VkDeviceGroupCommandBufferBeginInfo;

or the equivalent

    typedef VkDeviceGroupCommandBufferBeginInfo VkDeviceGroupCommandBufferBeginInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `deviceMask` is the initial value of the command buffer’s device mask.

The initial device mask also acts as an upper bound on the set of devices that can ever be in the device mask in the command buffer.

If this structure is not present, the initial value of a command buffer’s device mask is set to include all physical devices in the logical device when the command buffer begins recording.

Valid Usage

- `deviceMask` must be a valid device mask value

- `deviceMask` must not be zero

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEVICE_GROUP_COMMAND_BUFFER_BEGIN_INFO`

To update the current device mask of a command buffer, call:

    void vkCmdSetDeviceMask(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    deviceMask);

or the equivalent command

    void vkCmdSetDeviceMaskKHR(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    deviceMask);

- `commandBuffer` is command buffer whose current device mask is modified.

- `deviceMask` is the new value of the current device mask.

`deviceMask` is used to filter out subsequent commands from executing on all physical devices whose bit indices are not set in the mask, except commands beginning a render pass instance, commands transitioning to the next subpass in the render pass instance, and commands ending a render pass instance, which always execute on the set of physical devices whose bit indices are included in the `deviceMask` member of the VkDeviceGroupRenderPassBeginInfo structure passed to the command beginning the corresponding render pass instance.

Valid Usage

- `deviceMask` must be a valid device mask value

- `deviceMask` must not be zero

- `deviceMask` must not include any set bits that were not in the VkDeviceGroupCommandBufferBeginInfo::`deviceMask` value when the command buffer began recording.

- If `vkCmdSetDeviceMask` is called inside a render pass instance, `deviceMask` must not include any set bits that were not in the VkDeviceGroupRenderPassBeginInfo::`deviceMask` value when the render pass instance began recording.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, compute, or transfer operations

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute Transfer |

## 6. Synchronization and Cache Control

Synchronization of access to resources is primarily the responsibility of the application in Vulkan. The order of execution of commands with respect to the host and other commands on the device has few implicit guarantees, and needs to be explicitly specified. Memory caches and other optimizations are also explicitly managed, requiring that the flow of data through the system is largely under application control.

Whilst some implicit guarantees exist between commands, five explicit synchronization mechanisms are exposed by Vulkan:

Fences

  Fences can be used to communicate to the host that execution of some task on the device has completed.

Semaphores

  Semaphores can be used to control resource access across multiple queues.

Events

  Events provide a fine-grained synchronization primitive which can be signaled either within a command buffer or by the host, and can be waited upon within a command buffer or queried on the host.

Pipeline Barriers

  Pipeline barriers also provide synchronization control within a command buffer, but at a single point, rather than with separate signal and wait operations.

Render Passes

  Render passes provide a useful synchronization framework for most rendering tasks, built upon the concepts in this chapter. Many cases that would otherwise need an application to use other synchronization primitives can be expressed more efficiently as part of a render pass.

### 6.1. Execution and Memory Dependencies

An operation is an arbitrary amount of work to be executed on the host, a device, or an external entity such as a presentation engine. Synchronization commands introduce explicit execution dependencies, and memory dependencies between two sets of operations defined by the command’s two synchronization scopes.

The synchronization scopes define which other operations a synchronization command is able to create execution dependencies with. Any type of operation that is not in a synchronization command’s synchronization scopes will not be included in the resulting dependency. For example, for many synchronization commands, the synchronization scopes can be limited to just operations executing in specific pipeline stages, which allows other pipeline stages to be excluded from a dependency. Other scoping options are possible, depending on the particular command.

An execution dependency is a guarantee that for two sets of operations, the first set must happen-before the second set. If an operation happens-before another operation, then the first operation must complete before the second operation is initiated. More precisely:

- Let A and B be separate sets of operations.

- Let S be a synchronization command.

- Let AS and BS be the synchronization scopes of S.

- Let A' be the intersection of sets A and AS.

- Let B' be the intersection of sets B and BS.

- Submitting A, S and B for execution, in that order, will result in execution dependency E between A' and B'.

- Execution dependency E guarantees that A' happens-before B'.

An execution dependency chain is a sequence of execution dependencies that form a happens-before relation between the first dependency’s A' and the final dependency’s B'. For each consecutive pair of execution dependencies, a chain exists if the intersection of BS in the first dependency and AS in the second dependency is not an empty set. The formation of a single execution dependency from an execution dependency chain can be described by substituting the following in the description of execution dependencies:

- Let S be a set of synchronization commands that generate an execution dependency chain.

- Let AS be the first synchronization scope of the first command in S.

- Let BS be the second synchronization scope of the last command in S.

Execution dependencies alone are not sufficient to guarantee that values resulting from writes in one set of operations can be read from another set of operations.

Three additional types of operation are used to control memory access. Availability operations cause the values generated by specified memory write accesses to become available to a memory domain for future access. Any available value remains available until a subsequent write to the same memory location occurs (whether it is made available or not) or the memory is freed. Memory domain operations cause writes that are available to a source memory domain to become available to a destination memory domain (an example of this is making writes available to the host domain available to the device domain). Visibility operations cause values available to a memory domain to become visible to specified memory accesses.

Availability, visibility, memory domains, and memory domain operations are formally defined in the Availability and Visibility section of the Memory Model chapter. Which API operations perform each of these operations is defined in Availability, Visibility, and Domain Operations.

A memory dependency is an execution dependency which includes availability and visibility operations such that:

- The first set of operations happens-before the availability operation.

- The availability operation happens-before the visibility operation.

- The visibility operation happens-before the second set of operations.

Once written values are made visible to a particular type of memory access, they can be read or written by that type of memory access. Most synchronization commands in Vulkan define a memory dependency.

The specific memory accesses that are made available and visible are defined by the access scopes of a memory dependency. Any type of access that is in a memory dependency’s first access scope and occurs in A' is made available. Any type of access that is in a memory dependency’s second access scope and occurs in B' has any available writes made visible to it. Any type of operation that is not in a synchronization command’s access scopes will not be included in the resulting dependency.

A memory dependency enforces availability and visibility of memory accesses and execution order between two sets of operations. Adding to the description of execution dependency chains:

- Let a be the set of memory accesses performed by A'.

- Let b be the set of memory accesses performed by B'.

- Let aS be the first access scope of the first command in S.

- Let bS be the second access scope of the last command in S.

- Let a' be the intersection of sets a and aS.

- Let b' be the intersection of sets b and bS.

- Submitting A, S and B for execution, in that order, will result in a memory dependency m between A' and B'.

- Memory dependency m guarantees that:

  - Memory writes in a' are made available.

  - Available memory writes, including those from a', are made visible to b'.

| Note Execution and memory dependencies are used to solve data hazards, i.e. to ensure that read and write operations occur in a well-defined order. Write-after-read hazards can be solved with just an execution dependency, but read-after-write and write-after-write hazards need appropriate memory dependencies to be included between them. If an application does not include dependencies to solve these hazards, the results and execution orders of memory accesses are undefined.

#### 6.1.1. Image Layout Transitions

Image subresources can be transitioned from one layout to another as part of a memory dependency (e.g. by using an image memory barrier). When a layout transition is specified in a memory dependency, it happens-after the availability operations in the memory dependency, and happens-before the visibility operations. Image layout transitions may perform read and write accesses on all memory bound to the image subresource range, so applications must ensure that all memory writes have been made available before a layout transition is executed. Available memory is automatically made visible to a layout transition, and writes performed by a layout transition are automatically made available.

Layout transitions always apply to a particular image subresource range, and specify both an old layout and new layout. If the old layout does not match the new layout, a transition occurs. The old layout must match the current layout of the image subresource range, with one exception. The old layout can always be specified as `VK_IMAGE_LAYOUT_UNDEFINED`, though doing so invalidates the contents of the image subresource range.

| Note Setting the old layout to `VK_IMAGE_LAYOUT_UNDEFINED` implies that the contents of the image subresource need not be preserved. Implementations may use this information to avoid performing expensive data transition operations.

As image layout transitions may perform read and write accesses on the memory bound to the image, if the image subresource affected by the layout transition is bound to peer memory for any device in the current device mask then the memory heap the bound memory comes from must support the `VK_PEER_MEMORY_FEATURE_GENERIC_SRC_BIT` and `VK_PEER_MEMORY_FEATURE_GENERIC_DST_BIT` capabilities as returned by vkGetDeviceGroupPeerMemoryFeatures.

| Note Applications must ensure that layout transitions happen-after all operations accessing the image with the old layout, and happen-before any operations that will access the image with the new layout. Layout transitions are potentially read/write operations, so not defining appropriate memory dependencies to guarantee this will result in a data race.

Image layout transitions interact with memory aliasing.

#### 6.1.2. Pipeline Stages

The work performed by an action or synchronization command consists of multiple operations, which are performed as a sequence of logically independent steps known as pipeline stages. The exact pipeline stages executed depend on the particular command that is used, and current command buffer state when the command was recorded. Drawing commands, dispatching commands, copy commands, clear commands, and synchronization commands all execute in different sets of pipeline stages. Synchronization commands do not execute in a defined pipeline, but do execute `VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT` and `VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT`.

| Note Operations performed by synchronization commands (e.g. availability and visibility operations) are not executed by a defined pipeline stage. However other commands can still synchronize with them via the `VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT` and `VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT` pipeline stages.

Execution of operations across pipeline stages must adhere to implicit ordering guarantees, particularly including pipeline stage order. Otherwise, execution across pipeline stages may overlap or execute out of order with regards to other stages, unless otherwise enforced by an execution dependency.

Several of the synchronization commands include pipeline stage parameters, restricting the synchronization scopes for that command to just those stages. This allows fine grained control over the exact execution dependencies and accesses performed by action commands. Implementations should use these pipeline stages to avoid unnecessary stalls or cache flushing.

Bits which can be set, specifying pipeline stages, are:

    typedef enum VkPipelineStageFlagBits {
        VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT = 0x00000001,
        VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT = 0x00000002,
        VK_PIPELINE_STAGE_VERTEX_INPUT_BIT = 0x00000004,
        VK_PIPELINE_STAGE_VERTEX_SHADER_BIT = 0x00000008,
        VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT = 0x00000010,
        VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT = 0x00000020,
        VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT = 0x00000040,
        VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT = 0x00000080,
        VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT = 0x00000100,
        VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT = 0x00000200,
        VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT = 0x00000400,
        VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT = 0x00000800,
        VK_PIPELINE_STAGE_TRANSFER_BIT = 0x00001000,
        VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT = 0x00002000,
        VK_PIPELINE_STAGE_HOST_BIT = 0x00004000,
        VK_PIPELINE_STAGE_ALL_GRAPHICS_BIT = 0x00008000,
        VK_PIPELINE_STAGE_ALL_COMMANDS_BIT = 0x00010000,
        VK_PIPELINE_STAGE_TRANSFORM_FEEDBACK_BIT_EXT = 0x01000000,
        VK_PIPELINE_STAGE_CONDITIONAL_RENDERING_BIT_EXT = 0x00040000,
        VK_PIPELINE_STAGE_RAY_TRACING_SHADER_BIT_KHR = 0x00200000,
        VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_KHR = 0x02000000,
        VK_PIPELINE_STAGE_SHADING_RATE_IMAGE_BIT_NV = 0x00400000,
        VK_PIPELINE_STAGE_TASK_SHADER_BIT_NV = 0x00080000,
        VK_PIPELINE_STAGE_MESH_SHADER_BIT_NV = 0x00100000,
        VK_PIPELINE_STAGE_FRAGMENT_DENSITY_PROCESS_BIT_EXT = 0x00800000,
        VK_PIPELINE_STAGE_COMMAND_PREPROCESS_BIT_NV = 0x00020000,
        VK_PIPELINE_STAGE_RAY_TRACING_SHADER_BIT_NV = VK_PIPELINE_STAGE_RAY_TRACING_SHADER_BIT_KHR,
        VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_NV = VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_KHR,
        VK_PIPELINE_STAGE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkPipelineStageFlagBits;

- `VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT` specifies the stage of the pipeline where any commands are initially received by the queue.

- `VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT` specifies the stage of the pipeline where Draw/DispatchIndirect data structures are consumed. This stage also includes reading commands written by vkCmdExecuteGeneratedCommandsNV.

- `VK_PIPELINE_STAGE_TASK_SHADER_BIT_NV` specifies the task shader stage.

- `VK_PIPELINE_STAGE_MESH_SHADER_BIT_NV` specifies the mesh shader stage.

- `VK_PIPELINE_STAGE_VERTEX_INPUT_BIT` specifies the stage of the pipeline where vertex and index buffers are consumed.

- `VK_PIPELINE_STAGE_VERTEX_SHADER_BIT` specifies the vertex shader stage.

- `VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT` specifies the tessellation control shader stage.

- `VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT` specifies the tessellation evaluation shader stage.

- `VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT` specifies the geometry shader stage.

- `VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT` specifies the fragment shader stage.

- `VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT` specifies the stage of the pipeline where early fragment tests (depth and stencil tests before fragment shading) are performed. This stage also includes subpass load operations for framebuffer attachments with a depth/stencil format.

- `VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT` specifies the stage of the pipeline where late fragment tests (depth and stencil tests after fragment shading) are performed. This stage also includes subpass store operations for framebuffer attachments with a depth/stencil format.

- `VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT` specifies the stage of the pipeline after blending where the final color values are output from the pipeline. This stage also includes subpass load and store operations and multisample resolve operations for framebuffer attachments with a color or depth/stencil format.

- `VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT` specifies the execution of a compute shader.

- `VK_PIPELINE_STAGE_TRANSFER_BIT` specifies the following commands:

  - All copy commands, including vkCmdCopyQueryPoolResults

  - vkCmdBlitImage

  - vkCmdResolveImage

  - All clear commands, with the exception of vkCmdClearAttachments

- `VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT` specifies the final stage in the pipeline where operations generated by all commands complete execution.

- `VK_PIPELINE_STAGE_HOST_BIT` specifies a pseudo-stage indicating execution on the host of reads/writes of device memory. This stage is not invoked by any commands recorded in a command buffer.

- `VK_PIPELINE_STAGE_RAY_TRACING_SHADER_BIT_KHR` specifies the execution of the ray tracing shader stages.

- `VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_KHR` specifies the execution of vkCmdBuildAccelerationStructureKHR, vkCmdCopyAccelerationStructureKHR, and vkCmdWriteAccelerationStructuresPropertiesKHR.

- `VK_PIPELINE_STAGE_ALL_GRAPHICS_BIT` specifies the execution of all graphics pipeline stages, and is equivalent to the logical OR of:

  - `VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT`

  - `VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT`

  - `VK_PIPELINE_STAGE_TASK_SHADER_BIT_NV`

  - `VK_PIPELINE_STAGE_MESH_SHADER_BIT_NV`

  - `VK_PIPELINE_STAGE_VERTEX_INPUT_BIT`

  - `VK_PIPELINE_STAGE_VERTEX_SHADER_BIT`

  - `VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT`

  - `VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT`

  - `VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT`

  - `VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT`

  - `VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT`

  - `VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT`

  - `VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT`

  - `VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT`

  - `VK_PIPELINE_STAGE_CONDITIONAL_RENDERING_BIT_EXT`

  - `VK_PIPELINE_STAGE_TRANSFORM_FEEDBACK_BIT_EXT`

  - `VK_PIPELINE_STAGE_SHADING_RATE_IMAGE_BIT_NV`

  - `VK_PIPELINE_STAGE_FRAGMENT_DENSITY_PROCESS_BIT_EXT`

- `VK_PIPELINE_STAGE_ALL_COMMANDS_BIT` is equivalent to the logical OR of every other pipeline stage flag that is supported on the queue it is used with.

- `VK_PIPELINE_STAGE_CONDITIONAL_RENDERING_BIT_EXT` specifies the stage of the pipeline where the predicate of conditional rendering is consumed.

- `VK_PIPELINE_STAGE_TRANSFORM_FEEDBACK_BIT_EXT` specifies the stage of the pipeline where vertex attribute output values are written to the transform feedback buffers.

- `VK_PIPELINE_STAGE_COMMAND_PREPROCESS_BIT_NV` specifies the stage of the pipeline where device-side preprocessing for generated commands via vkCmdPreprocessGeneratedCommandsNV is handled.

- `VK_PIPELINE_STAGE_SHADING_RATE_IMAGE_BIT_NV` specifies the stage of the pipeline where the shading rate image is read to determine the shading rate for portions of a rasterized primitive.

- `VK_PIPELINE_STAGE_FRAGMENT_DENSITY_PROCESS_BIT_EXT` specifies the stage of the pipeline where the fragment density map is read to generate the fragment areas.

| Note An execution dependency with only `VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT` in the destination stage mask will only prevent that stage from executing in subsequently submitted commands. As this stage does not perform any actual execution, this is not observable - in effect, it does not delay processing of subsequent commands. Similarly an execution dependency with only `VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT` in the source stage mask will effectively not wait for any prior commands to complete. When defining a memory dependency, using only `VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT` or `VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT` would never make any accesses available and/or visible because these stages do not access memory. `VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT` and `VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT` are useful for accomplishing layout transitions and queue ownership operations when the required execution dependency is satisfied by other means - for example, semaphore operations between queues.

    typedef VkFlags VkPipelineStageFlags;

`VkPipelineStageFlags` is a bitmask type for setting a mask of zero or more VkPipelineStageFlagBits.

If a synchronization command includes a source stage mask, its first synchronization scope only includes execution of the pipeline stages specified in that mask, and its first access scope only includes memory access performed by pipeline stages specified in that mask. If a synchronization command includes a destination stage mask, its second synchronization scope only includes execution of the pipeline stages specified in that mask, and its second access scope only includes memory access performed by pipeline stages specified in that mask.

| Note Including a particular pipeline stage in the first synchronization scope of a command implicitly includes logically earlier pipeline stages in the synchronization scope. Similarly, the second synchronization scope includes logically later pipeline stages. However, note that access scopes are not affected in this way - only the precise stages specified are considered part of each access scope.

Certain pipeline stages are only available on queues that support a particular set of operations. The following table lists, for each pipeline stage flag, which queue capability flag must be supported by the queue. When multiple flags are enumerated in the second column of the table, it means that the pipeline stage is supported on the queue if it supports any of the listed capability flags. For further details on queue capabilities see Physical Device Enumeration and Queues.

Table 3. Supported pipeline stage flags
Pipeline stage flag | Required queue capability flag
--- | ---
`VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT` | None required
`VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT` | `VK_QUEUE_GRAPHICS_BIT` or `VK_QUEUE_COMPUTE_BIT`
`VK_PIPELINE_STAGE_VERTEX_INPUT_BIT` | `VK_QUEUE_GRAPHICS_BIT`
`VK_PIPELINE_STAGE_VERTEX_SHADER_BIT` | `VK_QUEUE_GRAPHICS_BIT`
`VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT` | `VK_QUEUE_GRAPHICS_BIT`
`VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT` | `VK_QUEUE_GRAPHICS_BIT`
`VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT` | `VK_QUEUE_GRAPHICS_BIT`
`VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT` | `VK_QUEUE_GRAPHICS_BIT`
`VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT` | `VK_QUEUE_GRAPHICS_BIT`
`VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT` | `VK_QUEUE_GRAPHICS_BIT`
`VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT` | `VK_QUEUE_GRAPHICS_BIT`
`VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT` | `VK_QUEUE_COMPUTE_BIT`
`VK_PIPELINE_STAGE_TRANSFER_BIT` | `VK_QUEUE_GRAPHICS_BIT`, `VK_QUEUE_COMPUTE_BIT` or `VK_QUEUE_TRANSFER_BIT`
`VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT` | None required
`VK_PIPELINE_STAGE_HOST_BIT` | None required
`VK_PIPELINE_STAGE_ALL_GRAPHICS_BIT` | `VK_QUEUE_GRAPHICS_BIT`
`VK_PIPELINE_STAGE_ALL_COMMANDS_BIT` | None required
`VK_PIPELINE_STAGE_CONDITIONAL_RENDERING_BIT_EXT` | `VK_QUEUE_GRAPHICS_BIT` or `VK_QUEUE_COMPUTE_BIT`
`VK_PIPELINE_STAGE_TRANSFORM_FEEDBACK_BIT_EXT` | `VK_QUEUE_GRAPHICS_BIT`
`VK_PIPELINE_STAGE_COMMAND_PREPROCESS_BIT_NV` | `VK_QUEUE_GRAPHICS_BIT` or `VK_QUEUE_COMPUTE_BIT`
`VK_PIPELINE_STAGE_SHADING_RATE_IMAGE_BIT_NV` | `VK_QUEUE_GRAPHICS_BIT`
`VK_PIPELINE_STAGE_TASK_SHADER_BIT_NV` | `VK_QUEUE_GRAPHICS_BIT`
`VK_PIPELINE_STAGE_MESH_SHADER_BIT_NV` | `VK_QUEUE_GRAPHICS_BIT`
`VK_PIPELINE_STAGE_RAY_TRACING_SHADER_BIT_KHR` | `VK_QUEUE_COMPUTE_BIT`
`VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_KHR` | `VK_QUEUE_COMPUTE_BIT`
`VK_PIPELINE_STAGE_FRAGMENT_DENSITY_PROCESS_BIT_EXT` | `VK_QUEUE_GRAPHICS_BIT`

Pipeline stages that execute as a result of a command logically complete execution in a specific order, such that completion of a logically later pipeline stage must not happen-before completion of a logically earlier stage. This means that including any stage in the source stage mask for a particular synchronization command also implies that any logically earlier stages are included in AS for that command.

Similarly, initiation of a logically earlier pipeline stage must not happen-after initiation of a logically later pipeline stage. Including any given stage in the destination stage mask for a particular synchronization command also implies that any logically later stages are included in BS for that command.

| Note Implementations may not support synchronization at every pipeline stage for every synchronization operation. If a pipeline stage that an implementation does not support synchronization for appears in a source stage mask, it may substitute any logically later stage in its place for the first synchronization scope. If a pipeline stage that an implementation does not support synchronization for appears in a destination stage mask, it may substitute any logically earlier stage in its place for the second synchronization scope. For example, if an implementation is unable to signal an event immediately after vertex shader execution is complete, it may instead signal the event after color attachment output has completed. If an implementation makes such a substitution, it must not affect the semantics of execution or memory dependencies or image and buffer memory barriers.

The order and set of pipeline stages executed by a given command is determined by the command’s pipeline type, as described below:

For the graphics primitive shading pipeline, the following stages occur in this order:

- `VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT`

- `VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT`

- `VK_PIPELINE_STAGE_VERTEX_INPUT_BIT`

- `VK_PIPELINE_STAGE_VERTEX_SHADER_BIT`

- `VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT`

- `VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT`

- `VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT`

- `VK_PIPELINE_STAGE_TRANSFORM_FEEDBACK_BIT_EXT`

- `VK_PIPELINE_STAGE_SHADING_RATE_IMAGE_BIT_NV`

- `VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT`

- `VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT`

- `VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT`

- `VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT`

- `VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT`

For the graphics mesh shading pipeline, the following stages occur in this order:

- `VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT`

- `VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT`

- `VK_PIPELINE_STAGE_TASK_SHADER_BIT_NV`

- `VK_PIPELINE_STAGE_MESH_SHADER_BIT_NV`

- `VK_PIPELINE_STAGE_SHADING_RATE_IMAGE_BIT_NV`

- `VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT`

- `VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT`

- `VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT`

- `VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT`

- `VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT`

For graphics pipeline commands executing in a render pass with a fragment density map attachment, the following pipeline stage where the fragment density map read happens has no particular order relative to the other stages, except that it is logically earlier than `VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT`:

- `VK_PIPELINE_STAGE_FRAGMENT_DENSITY_PROCESS_BIT_EXT`

- `VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT`

For the compute pipeline, the following stages occur in this order:

- `VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT`

- `VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT`

- `VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT`

- `VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT`

The conditional rendering stage is formally part of both the graphics, and the compute pipeline. The pipeline stage where the predicate read happens has unspecified order relative to other stages of these pipelines:

- `VK_PIPELINE_STAGE_CONDITIONAL_RENDERING_BIT_EXT`

For the transfer pipeline, the following stages occur in this order:

- `VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT`

- `VK_PIPELINE_STAGE_TRANSFER_BIT`

- `VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT`

For host operations, only one pipeline stage occurs, so no order is guaranteed:

- `VK_PIPELINE_STAGE_HOST_BIT`

For the command preprocessing pipeline, the following stages occur in this order:

- `VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT`

- `VK_PIPELINE_STAGE_COMMAND_PREPROCESS_BIT_NV`

- `VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT`

For the ray tracing shader pipeline, only one pipeline stage occurs, so no order is guaranteed:

- `VK_PIPELINE_STAGE_RAY_TRACING_SHADER_BIT_KHR`

For ray tracing acceleration structure operations, only one pipeline stage occurs, so no order is guaranteed:

- `VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_KHR`

#### 6.1.3. Access Types

Memory in Vulkan can be accessed from within shader invocations and via some fixed-function stages of the pipeline. The access type is a function of the descriptor type used, or how a fixed-function stage accesses memory. Each access type corresponds to a bit flag in VkAccessFlagBits.

Some synchronization commands take sets of access types as parameters to define the access scopes of a memory dependency. If a synchronization command includes a source access mask, its first access scope only includes accesses via the access types specified in that mask. Similarly, if a synchronization command includes a destination access mask, its second access scope only includes accesses via the access types specified in that mask.

Access types that can be set in an access mask include:

    typedef enum VkAccessFlagBits {
        VK_ACCESS_INDIRECT_COMMAND_READ_BIT = 0x00000001,
        VK_ACCESS_INDEX_READ_BIT = 0x00000002,
        VK_ACCESS_VERTEX_ATTRIBUTE_READ_BIT = 0x00000004,
        VK_ACCESS_UNIFORM_READ_BIT = 0x00000008,
        VK_ACCESS_INPUT_ATTACHMENT_READ_BIT = 0x00000010,
        VK_ACCESS_SHADER_READ_BIT = 0x00000020,
        VK_ACCESS_SHADER_WRITE_BIT = 0x00000040,
        VK_ACCESS_COLOR_ATTACHMENT_READ_BIT = 0x00000080,
        VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT = 0x00000100,
        VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_READ_BIT = 0x00000200,
        VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT = 0x00000400,
        VK_ACCESS_TRANSFER_READ_BIT = 0x00000800,
        VK_ACCESS_TRANSFER_WRITE_BIT = 0x00001000,
        VK_ACCESS_HOST_READ_BIT = 0x00002000,
        VK_ACCESS_HOST_WRITE_BIT = 0x00004000,
        VK_ACCESS_MEMORY_READ_BIT = 0x00008000,
        VK_ACCESS_MEMORY_WRITE_BIT = 0x00010000,
        VK_ACCESS_TRANSFORM_FEEDBACK_WRITE_BIT_EXT = 0x02000000,
        VK_ACCESS_TRANSFORM_FEEDBACK_COUNTER_READ_BIT_EXT = 0x04000000,
        VK_ACCESS_TRANSFORM_FEEDBACK_COUNTER_WRITE_BIT_EXT = 0x08000000,
        VK_ACCESS_CONDITIONAL_RENDERING_READ_BIT_EXT = 0x00100000,
        VK_ACCESS_COLOR_ATTACHMENT_READ_NONCOHERENT_BIT_EXT = 0x00080000,
        VK_ACCESS_ACCELERATION_STRUCTURE_READ_BIT_KHR = 0x00200000,
        VK_ACCESS_ACCELERATION_STRUCTURE_WRITE_BIT_KHR = 0x00400000,
        VK_ACCESS_SHADING_RATE_IMAGE_READ_BIT_NV = 0x00800000,
        VK_ACCESS_FRAGMENT_DENSITY_MAP_READ_BIT_EXT = 0x01000000,
        VK_ACCESS_COMMAND_PREPROCESS_READ_BIT_NV = 0x00020000,
        VK_ACCESS_COMMAND_PREPROCESS_WRITE_BIT_NV = 0x00040000,
        VK_ACCESS_ACCELERATION_STRUCTURE_READ_BIT_NV = VK_ACCESS_ACCELERATION_STRUCTURE_READ_BIT_KHR,
        VK_ACCESS_ACCELERATION_STRUCTURE_WRITE_BIT_NV = VK_ACCESS_ACCELERATION_STRUCTURE_WRITE_BIT_KHR,
        VK_ACCESS_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkAccessFlagBits;

- `VK_ACCESS_INDIRECT_COMMAND_READ_BIT` specifies read access to indirect command data read as part of an indirect drawing or dispatch command.

- `VK_ACCESS_INDEX_READ_BIT` specifies read access to an index buffer as part of an indexed drawing command, bound by vkCmdBindIndexBuffer.

- `VK_ACCESS_VERTEX_ATTRIBUTE_READ_BIT` specifies read access to a vertex buffer as part of a drawing command, bound by vkCmdBindVertexBuffers.

- `VK_ACCESS_UNIFORM_READ_BIT` specifies read access to a uniform buffer.

- `VK_ACCESS_INPUT_ATTACHMENT_READ_BIT` specifies read access to an input attachment within a render pass during fragment shading.

- `VK_ACCESS_SHADER_READ_BIT` specifies read access to a storage buffer, physical storage buffer, uniform texel buffer, storage texel buffer, sampled image, or storage image.

- `VK_ACCESS_SHADER_WRITE_BIT` specifies write access to a storage buffer, physical storage buffer, storage texel buffer, or storage image.

- `VK_ACCESS_COLOR_ATTACHMENT_READ_BIT` specifies read access to a color attachment, such as via blending, logic operations, or via certain subpass load operations. It does not include advanced blend operations.

- `VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT` specifies write access to a color, resolve, or depth/stencil resolve attachment during a render pass or via certain subpass load and store operations.

- `VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_READ_BIT` specifies read access to a depth/stencil attachment, via depth or stencil operations or via certain subpass load operations.

- `VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT` specifies write access to a depth/stencil attachment, via depth or stencil operations or via certain subpass load and store operations.

- `VK_ACCESS_TRANSFER_READ_BIT` specifies read access to an image or buffer in a copy operation.

- `VK_ACCESS_TRANSFER_WRITE_BIT` specifies write access to an image or buffer in a clear or copy operation.

- `VK_ACCESS_HOST_READ_BIT` specifies read access by a host operation. Accesses of this type are not performed through a resource, but directly on memory.

- `VK_ACCESS_HOST_WRITE_BIT` specifies write access by a host operation. Accesses of this type are not performed through a resource, but directly on memory.

- `VK_ACCESS_MEMORY_READ_BIT` specifies all read accesses. It is always valid in any access mask, and is treated as equivalent to setting all `READ` access flags that are valid where it is used.

- `VK_ACCESS_MEMORY_WRITE_BIT` specifies all write accesses. It is always valid in any access mask, and is treated as equivalent to setting all `WRITE` access flags that are valid where it is used.

- `VK_ACCESS_CONDITIONAL_RENDERING_READ_BIT_EXT` specifies read access to a predicate as part of conditional rendering.

- `VK_ACCESS_TRANSFORM_FEEDBACK_WRITE_BIT_EXT` specifies write access to a transform feedback buffer made when transform feedback is active.

- `VK_ACCESS_TRANSFORM_FEEDBACK_COUNTER_READ_BIT_EXT` specifies read access to a transform feedback counter buffer which is read when `vkCmdBeginTransformFeedbackEXT` executes.

- `VK_ACCESS_TRANSFORM_FEEDBACK_COUNTER_WRITE_BIT_EXT` specifies write access to a transform feedback counter buffer which is written when `vkCmdEndTransformFeedbackEXT` executes.

- `VK_ACCESS_COMMAND_PREPROCESS_READ_BIT_NV` specifies reads from `VkBuffer` inputs to vkCmdPreprocessGeneratedCommandsNV.

- `VK_ACCESS_COMMAND_PREPROCESS_WRITE_BIT_NV` specifies writes to the `VkBuffer` preprocess outputs in vkCmdPreprocessGeneratedCommandsNV.

- `VK_ACCESS_COLOR_ATTACHMENT_READ_NONCOHERENT_BIT_EXT` is similar to `VK_ACCESS_COLOR_ATTACHMENT_READ_BIT`, but also includes advanced blend operations.

- `VK_ACCESS_SHADING_RATE_IMAGE_READ_BIT_NV` specifies read access to a shading rate image as part of a drawing command, as bound by vkCmdBindShadingRateImageNV.

- `VK_ACCESS_ACCELERATION_STRUCTURE_READ_BIT_KHR` specifies read access to an acceleration structure as part of a trace or build command.

- `VK_ACCESS_ACCELERATION_STRUCTURE_WRITE_BIT_KHR` specifies write access to an acceleration structure as part of a build command.

- `VK_ACCESS_FRAGMENT_DENSITY_MAP_READ_BIT_EXT` specifies read access to a fragment density map attachment during dynamic fragment density map operations

Certain access types are only performed by a subset of pipeline stages. Any synchronization command that takes both stage masks and access masks uses both to define the access scopes - only the specified access types performed by the specified stages are included in the access scope. An application must not specify an access flag in a synchronization command if it does not include a pipeline stage in the corresponding stage mask that is able to perform accesses of that type. The following table lists, for each access flag, which pipeline stages can perform that type of access.

Table 4. Supported access types
Access flag | Supported pipeline stages
--- | ---
`VK_ACCESS_INDIRECT_COMMAND_READ_BIT` | `VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT`
`VK_ACCESS_INDEX_READ_BIT` | `VK_PIPELINE_STAGE_VERTEX_INPUT_BIT`
`VK_ACCESS_VERTEX_ATTRIBUTE_READ_BIT` | `VK_PIPELINE_STAGE_VERTEX_INPUT_BIT`
`VK_ACCESS_UNIFORM_READ_BIT` | `VK_PIPELINE_STAGE_TASK_SHADER_BIT_NV`, `VK_PIPELINE_STAGE_MESH_SHADER_BIT_NV`, `VK_PIPELINE_STAGE_RAY_TRACING_SHADER_BIT_KHR`, `VK_PIPELINE_STAGE_VERTEX_SHADER_BIT`, `VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT`, `VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT`, `VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT`, `VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT`, or `VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT`
`VK_ACCESS_SHADER_READ_BIT` | `VK_PIPELINE_STAGE_TASK_SHADER_BIT_NV`, `VK_PIPELINE_STAGE_MESH_SHADER_BIT_NV`, `VK_PIPELINE_STAGE_RAY_TRACING_SHADER_BIT_KHR`, `VK_PIPELINE_STAGE_VERTEX_SHADER_BIT`, `VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT`, `VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT`, `VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT`, `VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT`, or `VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT`
`VK_ACCESS_SHADER_WRITE_BIT` | `VK_PIPELINE_STAGE_TASK_SHADER_BIT_NV`, `VK_PIPELINE_STAGE_MESH_SHADER_BIT_NV`, `VK_PIPELINE_STAGE_RAY_TRACING_SHADER_BIT_KHR`, `VK_PIPELINE_STAGE_VERTEX_SHADER_BIT`, `VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT`, `VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT`, `VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT`, `VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT`, or `VK_PIPELINE_STAGE_COMPUTE_SHADER_BIT`
`VK_ACCESS_INPUT_ATTACHMENT_READ_BIT` | `VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT`
`VK_ACCESS_COLOR_ATTACHMENT_READ_BIT` | `VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT`
`VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT` | `VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT`
`VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_READ_BIT` | `VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT`, or `VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT`
`VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT` | `VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT`, or `VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT`
`VK_ACCESS_TRANSFER_READ_BIT` | `VK_PIPELINE_STAGE_TRANSFER_BIT`
`VK_ACCESS_TRANSFER_WRITE_BIT` | `VK_PIPELINE_STAGE_TRANSFER_BIT`
`VK_ACCESS_HOST_READ_BIT` | `VK_PIPELINE_STAGE_HOST_BIT`
`VK_ACCESS_HOST_WRITE_BIT` | `VK_PIPELINE_STAGE_HOST_BIT`
`VK_ACCESS_MEMORY_READ_BIT` | Any
`VK_ACCESS_MEMORY_WRITE_BIT` | Any
`VK_ACCESS_COLOR_ATTACHMENT_READ_NONCOHERENT_BIT_EXT` | `VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT`
`VK_ACCESS_COMMAND_PREPROCESS_READ_BIT_NV` | `VK_PIPELINE_STAGE_COMMAND_PREPROCESS_BIT_NV`
`VK_ACCESS_COMMAND_PREPROCESS_WRITE_BIT_NV` | `VK_PIPELINE_STAGE_COMMAND_PREPROCESS_BIT_NV`
`VK_ACCESS_CONDITIONAL_RENDERING_READ_BIT_EXT` | `VK_PIPELINE_STAGE_CONDITIONAL_RENDERING_BIT_EXT`
`VK_ACCESS_SHADING_RATE_IMAGE_READ_BIT_NV` | `VK_PIPELINE_STAGE_SHADING_RATE_IMAGE_BIT_NV`
`VK_ACCESS_TRANSFORM_FEEDBACK_WRITE_BIT_EXT` | `VK_PIPELINE_STAGE_TRANSFORM_FEEDBACK_BIT_EXT`
`VK_ACCESS_TRANSFORM_FEEDBACK_COUNTER_WRITE_BIT_EXT` | `VK_PIPELINE_STAGE_TRANSFORM_FEEDBACK_BIT_EXT`
`VK_ACCESS_TRANSFORM_FEEDBACK_COUNTER_READ_BIT_EXT` | `VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT`
`VK_ACCESS_ACCELERATION_STRUCTURE_READ_BIT_KHR` | `VK_PIPELINE_STAGE_RAY_TRACING_SHADER_BIT_KHR`, or `VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_KHR`
`VK_ACCESS_ACCELERATION_STRUCTURE_WRITE_BIT_KHR` | `VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_KHR`
`VK_ACCESS_FRAGMENT_DENSITY_MAP_READ_BIT_EXT` | `VK_PIPELINE_STAGE_FRAGMENT_DENSITY_PROCESS_BIT_EXT`

If a memory object does not have the `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT` property, then vkFlushMappedMemoryRanges must be called in order to guarantee that writes to the memory object from the host are made available to the host domain, where they can be further made available to the device domain via a domain operation. Similarly, vkInvalidateMappedMemoryRanges must be called to guarantee that writes which are available to the host domain are made visible to host operations.

If the memory object does have the `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT` property flag, writes to the memory object from the host are automatically made available to the host domain. Similarly, writes made available to the host domain are automatically made visible to the host.

| Note The vkQueueSubmit command automatically performs a domain operation from host to device for all writes performed before the command executes, so in most cases an explicit memory barrier is not needed for this case. In the few circumstances where a submit does not occur between the host write and the device read access, writes can be made available by using an explicit memory barrier.

    typedef VkFlags VkAccessFlags;

`VkAccessFlags` is a bitmask type for setting a mask of zero or more VkAccessFlagBits.

#### 6.1.4. Framebuffer Region Dependencies

Pipeline stages that operate on, or with respect to, the framebuffer are collectively the framebuffer-space pipeline stages. These stages are:

- `VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT`

- `VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT`

- `VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT`

- `VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT`

For these pipeline stages, an execution or memory dependency from the first set of operations to the second set can either be a single framebuffer-global dependency, or split into multiple framebuffer-local dependencies. A dependency with non-framebuffer-space pipeline stages is neither framebuffer-global nor framebuffer-local.

A framebuffer region is a set of sample (x, y, layer, sample) coordinates that is a subset of the entire framebuffer.

Both synchronization scopes of a framebuffer-local dependency include only the operations performed within corresponding framebuffer regions (as defined below). No ordering guarantees are made between different framebuffer regions for a framebuffer-local dependency.

Both synchronization scopes of a framebuffer-global dependency include operations on all framebuffer-regions.

If the first synchronization scope includes operations on pixels/fragments with N samples and the second synchronization scope includes operations on pixels/fragments with M samples, where N does not equal M, then a framebuffer region containing all samples at a given (x, y, layer) coordinate in the first synchronization scope corresponds to a region containing all samples at the same coordinate in the second synchronization scope. In other words, it is a pixel granularity dependency. If N equals M, then a framebuffer region containing a single (x, y, layer, sample) coordinate in the first synchronization scope corresponds to a region containing the same sample at the same coordinate in the second synchronization scope. In other words, it is a sample granularity dependency.

| Note Since fragment invocations are not specified to run in any particular groupings, the size of a framebuffer region is implementation-dependent, not known to the application, and must be assumed to be no larger than specified above.

| Note Practically, the pixel vs sample granularity dependency means that if an input attachment has a different number of samples than the pipeline’s `rasterizationSamples`, then a fragment can access any sample in the input attachment’s pixel even if it only uses framebuffer-local dependencies. If the input attachment has the same number of samples, then the fragment can only access the covered samples in its input `SampleMask` (i.e. the fragment operations happen-after a framebuffer-local dependency for each sample the fragment covers). To access samples that are not covered, a framebuffer-global dependency is required.

If a synchronization command includes a `dependencyFlags` parameter, and specifies the `VK_DEPENDENCY_BY_REGION_BIT` flag, then it defines framebuffer-local dependencies for the framebuffer-space pipeline stages in that synchronization command, for all framebuffer regions. If no `dependencyFlags` parameter is included, or the `VK_DEPENDENCY_BY_REGION_BIT` flag is not specified, then a framebuffer-global dependency is specified for those stages. The `VK_DEPENDENCY_BY_REGION_BIT` flag does not affect the dependencies between non-framebuffer-space pipeline stages, nor does it affect the dependencies between framebuffer-space and non-framebuffer-space pipeline stages.

| Note Framebuffer-local dependencies are more optimal for most architectures; particularly tile-based architectures - which can keep framebuffer-regions entirely in on-chip registers and thus avoid external bandwidth across such a dependency. Including a framebuffer-global dependency in your rendering will usually force all implementations to flush data to memory, or to a higher level cache, breaking any potential locality optimizations.

#### 6.1.5. View-Local Dependencies

In a render pass instance that has multiview enabled, dependencies can be either view-local or view-global.

A view-local dependency only includes operations from a single source view from the source subpass in the first synchronization scope, and only includes operations from a single destination view from the destination subpass in the second synchronization scope. A view-global dependency includes all views in the view mask of the source and destination subpasses in the corresponding synchronization scopes.

If a synchronization command includes a `dependencyFlags` parameter and specifies the `VK_DEPENDENCY_VIEW_LOCAL_BIT` flag, then it defines view-local dependencies for that synchronization command, for all views. If no `dependencyFlags` parameter is included or the `VK_DEPENDENCY_VIEW_LOCAL_BIT` flag is not specified, then a view-global dependency is specified.

#### 6.1.6. Device-Local Dependencies

Dependencies can be either device-local or non-device-local. A device-local dependency acts as multiple separate dependencies, one for each physical device that executes the synchronization command, where each dependency only includes operations from that physical device in both synchronization scopes. A non-device-local dependency is a single dependency where both synchronization scopes include operations from all physical devices that participate in the synchronization command. For subpass dependencies, all physical devices in the VkDeviceGroupRenderPassBeginInfo::`deviceMask` participate in the dependency, and for pipeline barriers all physical devices that are set in the command buffer’s current device mask participate in the dependency.

If a synchronization command includes a `dependencyFlags` parameter and specifies the `VK_DEPENDENCY_DEVICE_GROUP_BIT` flag, then it defines a non-device-local dependency for that synchronization command. If no `dependencyFlags` parameter is included or the `VK_DEPENDENCY_DEVICE_GROUP_BIT` flag is not specified, then it defines device-local dependencies for that synchronization command, for all participating physical devices.

Semaphore and event dependencies are device-local and only execute on the one physical device that performs the dependency.

### 6.2. Implicit Synchronization Guarantees

A small number of implicit ordering guarantees are provided by Vulkan, ensuring that the order in which commands are submitted is meaningful, and avoiding unnecessary complexity in common operations.

Submission order is a fundamental ordering in Vulkan, giving meaning to the order in which action and synchronization commands are recorded and submitted to a single queue. Explicit and implicit ordering guarantees between commands in Vulkan all work on the premise that this ordering is meaningful. This order does not itself define any execution or memory dependencies; synchronization commands and other orderings within the API use this ordering to define their scopes.

Submission order for any given set of commands is based on the order in which they were recorded to command buffers and then submitted. This order is determined as follows:

1. The initial order is determined by the order in which vkQueueSubmit commands are executed on the host, for a single queue, from first to last.

2. The order in which VkSubmitInfo structures are specified in the `pSubmits` parameter of vkQueueSubmit, from lowest index to highest.

3. The order in which command buffers are specified in the `pCommandBuffers` member of VkSubmitInfo, from lowest index to highest.

4. The order in which commands were recorded to a command buffer on the host, from first to last:

   - For commands recorded outside a render pass, this includes all other commands recorded outside a render pass, including vkCmdBeginRenderPass and vkCmdEndRenderPass commands; it does not directly include commands inside a render pass.

   - For commands recorded inside a render pass, this includes all other commands recorded inside the same subpass, including the vkCmdBeginRenderPass and vkCmdEndRenderPass commands that delimit the same render pass instance; it does not include commands recorded to other subpasses.

Action and synchronization commands recorded to a command buffer execute the `VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT` pipeline stage in submission order - forming an implicit execution dependency between this stage in each command.

State commands do not execute any operations on the device, instead they set the state of the command buffer when they execute on the host, in the order that they are recorded. Action commands consume the current state of the command buffer when they are recorded, and will execute state changes on the device as required to match the recorded state.

Query commands, the order of primitives passing through the graphics pipeline and image layout transitions as part of an image memory barrier provide additional guarantees based on submission order.

Execution of pipeline stages within a given command also has a loose ordering, dependent only on a single command.

Signal operation order is a fundamental ordering in Vulkan, giving meaning to the order in which semaphore and fence signal operations occur when submitted to a single queue. The signal operation order for queue operations is determined as follows:

1. The initial order is determined by the order in which vkQueueSubmit commands are executed on the host, for a single queue, from first to last.

2. The order in which VkSubmitInfo structures are specified in the `pSubmits` parameter of vkQueueSubmit, from lowest index to highest.

3. The fence signal operation defined by the `fence` parameter of a vkQueueSubmit or vkQueueBindSparse command is ordered after all semaphore signal operations defined by that command.

Semaphore signal operations defined by a single VkSubmitInfo or VkBindSparseInfo structure are unordered with respect to other semaphore signal operations defined within the same VkSubmitInfo or VkBindSparseInfo structure.

The vkSignalSemaphore command does not execute on a queue but instead performs the signal operation from the host. The semaphore signal operation defined by executing a vkSignalSemaphore command happens-after the vkSignalSemaphore command is invoked and happens-before the command returns.

| Note When signaling timeline semaphores, it is the responsibility of the client to ensure that they are ordered such that the semaphore value is strictly increasing. Because the first synchronization scope for a semaphore signal operation contains all semaphore signal operations which occur earlier in submission order, all semaphore signal operations contained in any given batch are guaranteed to happen-after all semaphore signal operations contained in any previous batches. However, no ordering guarantee is provided between the semaphore signal operations defined within a single batch. This, combined with the requirement that timeline semaphore values strictly increase, means that it is invalid to signal the same timeline semaphore twice within a single batch. If a client wishes to ensure that some semaphore signal operation happens-after some other semaphore signal operation, it can submit a separate batch containing only semaphore signal operations, which will happen-after the semaphore signal operations in any earlier batches. When signaling a semaphore from the host, the only ordering guarantee is that the signal operation happens-after when vkSignalSemaphore is called and happens-before it returns. Therefore, it is invalid to call `vkSignalSemaphore` while there are any outstanding signal operations on that semaphore from any queue submissions unless those queue submissions have some dependency which ensures that they happen-after the host signal operation. One example of this would be if the pending signal operation is, itself, waiting on the same semaphore at a lower value and the call to `vkSignalSemaphore` signals that lower value. Furthermore, if there are two or more processes or threads signaling the same timeline semaphore from the host, the client must ensure that the `vkSignalSemaphore` with the lower semaphore value returns before `vkSignalSemaphore` is called with the higher value.

### 6.3. Fences

Fences are a synchronization primitive that can be used to insert a dependency from a queue to the host. Fences have two states - signaled and unsignaled. A fence can be signaled as part of the execution of a queue submission command. Fences can be unsignaled on the host with vkResetFences. Fences can be waited on by the host with the vkWaitForFences command, and the current state can be queried with vkGetFenceStatus.

As with most objects in Vulkan, fences are an interface to internal data which is typically opaque to applications. This internal data is referred to as a fence’s payload.

However, in order to enable communication with agents outside of the current device, it is necessary to be able to export that payload to a commonly understood format, and subsequently import from that format as well.

The internal data of a fence may include a reference to any resources and pending work associated with signal or unsignal operations performed on that fence object. Mechanisms to import and export that internal data to and from fences are provided below. These mechanisms indirectly enable applications to share fence state between two or more fences and other synchronization primitives across process and API boundaries.

Fences are represented by `VkFence` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkFence)

To create a fence, call:

    VkResult vkCreateFence(
        VkDevice                                    device,
        const VkFenceCreateInfo*                    pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkFence*                                    pFence);

- `device` is the logical device that creates the fence.

- `pCreateInfo` is a pointer to a `VkFenceCreateInfo` structure containing information about how the fence is to be created.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pFence` is a pointer to a handle in which the resulting fence object is returned.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkFenceCreateInfo structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pFence` must be a valid pointer to a VkFence handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkFenceCreateInfo` structure is defined as:

    typedef struct VkFenceCreateInfo {
        VkStructureType       sType;
        const void*           pNext;
        VkFenceCreateFlags    flags;
    } VkFenceCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkFenceCreateFlagBits specifying the initial state and behavior of the fence.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_FENCE_CREATE_INFO`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkExportFenceCreateInfo or VkExportFenceWin32HandleInfoKHR

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be a valid combination of VkFenceCreateFlagBits values

    typedef enum VkFenceCreateFlagBits {
        VK_FENCE_CREATE_SIGNALED_BIT = 0x00000001,
        VK_FENCE_CREATE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkFenceCreateFlagBits;

- `VK_FENCE_CREATE_SIGNALED_BIT` specifies that the fence object is created in the signaled state. Otherwise, it is created in the unsignaled state.

    typedef VkFlags VkFenceCreateFlags;

`VkFenceCreateFlags` is a bitmask type for setting a mask of zero or more VkFenceCreateFlagBits.

To create a fence whose payload can be exported to external handles, add a VkExportFenceCreateInfo structure to the `pNext` chain of the VkFenceCreateInfo structure. The `VkExportFenceCreateInfo` structure is defined as:

    typedef struct VkExportFenceCreateInfo {
        VkStructureType                   sType;
        const void*                       pNext;
        VkExternalFenceHandleTypeFlags    handleTypes;
    } VkExportFenceCreateInfo;

or the equivalent

    typedef VkExportFenceCreateInfo VkExportFenceCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `handleTypes` is a bitmask of VkExternalFenceHandleTypeFlagBits specifying one or more fence handle types the application can export from the resulting fence. The application can request multiple handle types for the same fence.

Valid Usage

- The bits in `handleTypes` must be supported and compatible, as reported by VkExternalFenceProperties.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_EXPORT_FENCE_CREATE_INFO`

- `handleTypes` must be a valid combination of VkExternalFenceHandleTypeFlagBits values

To specify additional attributes of NT handles exported from a fence, add a VkExportFenceWin32HandleInfoKHR structure to the `pNext` chain of the VkFenceCreateInfo structure. The `VkExportFenceWin32HandleInfoKHR` structure is defined as:

    typedef struct VkExportFenceWin32HandleInfoKHR {
        VkStructureType               sType;
        const void*                   pNext;
        const SECURITY_ATTRIBUTES*    pAttributes;
        DWORD                         dwAccess;
        LPCWSTR                       name;
    } VkExportFenceWin32HandleInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `pAttributes` is a pointer to a Windows `SECURITY_ATTRIBUTES` structure specifying security attributes of the handle.

- `dwAccess` is a `DWORD` specifying access rights of the handle.

- `name` is a null-terminated UTF-16 string to associate with the underlying synchronization primitive referenced by NT handles exported from the created fence.

If VkExportFenceCreateInfo is not present in the same `pNext` chain, this structure is ignored.

If VkExportFenceCreateInfo is present in the `pNext` chain of VkFenceCreateInfo with a Windows `handleType`, but either `VkExportFenceWin32HandleInfoKHR` is not present in the `pNext` chain, or if it is but `pAttributes` is set to `NULL`, default security descriptor values will be used, and child processes created by the application will not inherit the handle, as described in the MSDN documentation for “Synchronization Object Security and Access Rights”1. Further, if the structure is not present, the access rights will be

`DXGI_SHARED_RESOURCE_READ` | `DXGI_SHARED_RESOURCE_WRITE`

for handles of the following types:

`VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_BIT`

1

  https://docs.microsoft.com/en-us/windows/win32/sync/synchronization-object-security-and-access-rights

Valid Usage

- If VkExportFenceCreateInfo::`handleTypes` does not include `VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_BIT`, a `VkExportFenceWin32HandleInfoKHR` structure must not be included in the `pNext` chain of VkFenceCreateInfo.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_EXPORT_FENCE_WIN32_HANDLE_INFO_KHR`

- If `pAttributes` is not `NULL`, `pAttributes` must be a valid pointer to a valid `SECURITY_ATTRIBUTES` value

To export a Windows handle representing the state of a fence, call:

    VkResult vkGetFenceWin32HandleKHR(
        VkDevice                                    device,
        const VkFenceGetWin32HandleInfoKHR*         pGetWin32HandleInfo,
        HANDLE*                                     pHandle);

- `device` is the logical device that created the fence being exported.

- `pGetWin32HandleInfo` is a pointer to a VkFenceGetWin32HandleInfoKHR structure containing parameters of the export operation.

- `pHandle` will return the Windows handle representing the fence state.

For handle types defined as NT handles, the handles returned by `vkGetFenceWin32HandleKHR` are owned by the application. To avoid leaking resources, the application must release ownership of them using the `CloseHandle` system call when they are no longer needed.

Exporting a Windows handle from a fence may have side effects depending on the transference of the specified handle type, as described in Importing Fence Payloads.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pGetWin32HandleInfo` must be a valid pointer to a valid VkFenceGetWin32HandleInfoKHR structure

- `pHandle` must be a valid pointer to a `HANDLE` value

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_TOO_MANY_OBJECTS`

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

The `VkFenceGetWin32HandleInfoKHR` structure is defined as:

    typedef struct VkFenceGetWin32HandleInfoKHR {
        VkStructureType                      sType;
        const void*                          pNext;
        VkFence                              fence;
        VkExternalFenceHandleTypeFlagBits    handleType;
    } VkFenceGetWin32HandleInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `fence` is the fence from which state will be exported.

- `handleType` is the type of handle requested.

The properties of the handle returned depend on the value of `handleType`. See VkExternalFenceHandleTypeFlagBits for a description of the properties of the defined external fence handle types.

Valid Usage

- `handleType` must have been included in VkExportFenceCreateInfo::`handleTypes` when the `fence`’s current payload was created.

- If `handleType` is defined as an NT handle, vkGetFenceWin32HandleKHR must be called no more than once for each valid unique combination of `fence` and `handleType`.

- `fence` must not currently have its payload replaced by an imported payload as described below in Importing Fence Payloads unless that imported payload’s handle type was included in VkExternalFenceProperties::`exportFromImportedHandleTypes` for `handleType`.

- If `handleType` refers to a handle type with copy payload transference semantics, `fence` must be signaled, or have an associated fence signal operation pending execution.

- `handleType` must be defined as an NT handle or a global share handle.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_FENCE_GET_WIN32_HANDLE_INFO_KHR`

- `pNext` must be `NULL`

- `fence` must be a valid VkFence handle

- `handleType` must be a valid VkExternalFenceHandleTypeFlagBits value

To export a POSIX file descriptor representing the payload of a fence, call:

    VkResult vkGetFenceFdKHR(
        VkDevice                                    device,
        const VkFenceGetFdInfoKHR*                  pGetFdInfo,
        int*                                        pFd);

- `device` is the logical device that created the fence being exported.

- `pGetFdInfo` is a pointer to a VkFenceGetFdInfoKHR structure containing parameters of the export operation.

- `pFd` will return the file descriptor representing the fence payload.

Each call to `vkGetFenceFdKHR` must create a new file descriptor and transfer ownership of it to the application. To avoid leaking resources, the application must release ownership of the file descriptor when it is no longer needed.

| Note Ownership can be released in many ways. For example, the application can call `close`() on the file descriptor, or transfer ownership back to Vulkan by using the file descriptor to import a fence payload.

If `pGetFdInfo->handleType` is `VK_EXTERNAL_FENCE_HANDLE_TYPE_SYNC_FD_BIT` and the fence is signaled at the time `vkGetFenceFdKHR` is called, `pFd` may return the value `-1` instead of a valid file descriptor.

Where supported by the operating system, the implementation must set the file descriptor to be closed automatically when an `execve` system call is made.

Exporting a file descriptor from a fence may have side effects depending on the transference of the specified handle type, as described in Importing Fence State.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pGetFdInfo` must be a valid pointer to a valid VkFenceGetFdInfoKHR structure

- `pFd` must be a valid pointer to an `int` value

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_TOO_MANY_OBJECTS`

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

The `VkFenceGetFdInfoKHR` structure is defined as:

    typedef struct VkFenceGetFdInfoKHR {
        VkStructureType                      sType;
        const void*                          pNext;
        VkFence                              fence;
        VkExternalFenceHandleTypeFlagBits    handleType;
    } VkFenceGetFdInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `fence` is the fence from which state will be exported.

- `handleType` is the type of handle requested.

The properties of the file descriptor returned depend on the value of `handleType`. See VkExternalFenceHandleTypeFlagBits for a description of the properties of the defined external fence handle types.

Valid Usage

- `handleType` must have been included in VkExportFenceCreateInfo::`handleTypes` when `fence`’s current payload was created.

- If `handleType` refers to a handle type with copy payload transference semantics, `fence` must be signaled, or have an associated fence signal operation pending execution.

- `fence` must not currently have its payload replaced by an imported payload as described below in Importing Fence Payloads unless that imported payload’s handle type was included in VkExternalFenceProperties::`exportFromImportedHandleTypes` for `handleType`.

- `handleType` must be defined as a POSIX file descriptor handle.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_FENCE_GET_FD_INFO_KHR`

- `pNext` must be `NULL`

- `fence` must be a valid VkFence handle

- `handleType` must be a valid VkExternalFenceHandleTypeFlagBits value

To destroy a fence, call:

    void vkDestroyFence(
        VkDevice                                    device,
        VkFence                                     fence,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that destroys the fence.

- `fence` is the handle of the fence to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage

- All queue submission commands that refer to `fence` must have completed execution

- If `VkAllocationCallbacks` were provided when `fence` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `fence` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `fence` is not VK_NULL_HANDLE, `fence` must be a valid VkFence handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- If `fence` is a valid handle, it must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `fence` must be externally synchronized

To query the status of a fence from the host, call:

    VkResult vkGetFenceStatus(
        VkDevice                                    device,
        VkFence                                     fence);

- `device` is the logical device that owns the fence.

- `fence` is the handle of the fence to query.

Upon success, `vkGetFenceStatus` returns the status of the fence object, with the following return codes:

Table 5. Fence Object Status Codes
Status | Meaning
--- | ---
`VK_SUCCESS` | The fence specified by `fence` is signaled.
`VK_NOT_READY` | The fence specified by `fence` is unsignaled.
`VK_ERROR_DEVICE_LOST` | The device has been lost. See Lost Device.

If a queue submission command is pending execution, then the value returned by this command may immediately be out of date.

If the device has been lost (see Lost Device), `vkGetFenceStatus` may return any of the above status codes. If the device has been lost and `vkGetFenceStatus` is called repeatedly, it will eventually return either `VK_SUCCESS` or `VK_ERROR_DEVICE_LOST`.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `fence` must be a valid VkFence handle

- `fence` must have been created, allocated, or retrieved from `device`

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_NOT_READY`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_DEVICE_LOST`

To set the state of fences to unsignaled from the host, call:

    VkResult vkResetFences(
        VkDevice                                    device,
        uint32_t                                    fenceCount,
        const VkFence*                              pFences);

- `device` is the logical device that owns the fences.

- `fenceCount` is the number of fences to reset.

- `pFences` is a pointer to an array of fence handles to reset.

If any member of `pFences` currently has its payload imported with temporary permanence, that fence’s prior permanent payload is first restored. The remaining operations described therefore operate on the restored payload.

When vkResetFences is executed on the host, it defines a fence unsignal operation for each fence, which resets the fence to the unsignaled state.

If any member of `pFences` is already in the unsignaled state when vkResetFences is executed, then vkResetFences has no effect on that fence.

Valid Usage

- Each element of `pFences` must not be currently associated with any queue command that has not yet completed execution on that queue

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pFences` must be a valid pointer to an array of `fenceCount` valid VkFence handles

- `fenceCount` must be greater than `0`

- Each element of `pFences` must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to each member of `pFences` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

When a fence is submitted to a queue as part of a queue submission command, it defines a memory dependency on the batches that were submitted as part of that command, and defines a fence signal operation which sets the fence to the signaled state.

The first synchronization scope includes every batch submitted in the same queue submission command. Fence signal operations that are defined by vkQueueSubmit additionally include in the first synchronization scope all commands that occur earlier in submission order. Fence signal operations that are defined by vkQueueSubmit or vkQueueBindSparse additionally include in the first synchronization scope any semaphore and fence signal operations that occur earlier in signal operation order.

The second synchronization scope only includes the fence signal operation.

The first access scope includes all memory access performed by the device.

The second access scope is empty.

To wait for one or more fences to enter the signaled state on the host, call:

    VkResult vkWaitForFences(
        VkDevice                                    device,
        uint32_t                                    fenceCount,
        const VkFence*                              pFences,
        VkBool32                                    waitAll,
        uint64_t                                    timeout);

- `device` is the logical device that owns the fences.

- `fenceCount` is the number of fences to wait on.

- `pFences` is a pointer to an array of `fenceCount` fence handles.

- `waitAll` is the condition that must be satisfied to successfully unblock the wait. If `waitAll` is `VK_TRUE`, then the condition is that all fences in `pFences` are signaled. Otherwise, the condition is that at least one fence in `pFences` is signaled.

- `timeout` is the timeout period in units of nanoseconds. `timeout` is adjusted to the closest value allowed by the implementation-dependent timeout accuracy, which may be substantially longer than one nanosecond, and may be longer than the requested period.

If the condition is satisfied when `vkWaitForFences` is called, then `vkWaitForFences` returns immediately. If the condition is not satisfied at the time `vkWaitForFences` is called, then `vkWaitForFences` will block and wait up to `timeout` nanoseconds for the condition to become satisfied.

If `timeout` is zero, then `vkWaitForFences` does not wait, but simply returns the current state of the fences. `VK_TIMEOUT` will be returned in this case if the condition is not satisfied, even though no actual wait was performed.

If the specified timeout period expires before the condition is satisfied, `vkWaitForFences` returns `VK_TIMEOUT`. If the condition is satisfied before `timeout` nanoseconds has expired, `vkWaitForFences` returns `VK_SUCCESS`.

If device loss occurs (see Lost Device) before the timeout has expired, `vkWaitForFences` must return in finite time with either `VK_SUCCESS` or `VK_ERROR_DEVICE_LOST`.

| Note While we guarantee that `vkWaitForFences` must return in finite time, no guarantees are made that it returns immediately upon device loss. However, the client can reasonably expect that the delay will be on the order of seconds and that calling `vkWaitForFences` will not result in a permanently (or seemingly permanently) dead process.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pFences` must be a valid pointer to an array of `fenceCount` valid VkFence handles

- `fenceCount` must be greater than `0`

- Each element of `pFences` must have been created, allocated, or retrieved from `device`

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_TIMEOUT`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_DEVICE_LOST`

An execution dependency is defined by waiting for a fence to become signaled, either via vkWaitForFences or by polling on vkGetFenceStatus.

The first synchronization scope includes only the fence signal operation.

The second synchronization scope includes the host operations of vkWaitForFences or vkGetFenceStatus indicating that the fence has become signaled.

| Note Signaling a fence and waiting on the host does not guarantee that the results of memory accesses will be visible to the host, as the access scope of a memory dependency defined by a fence only includes device access. A memory barrier or other memory dependency must be used to guarantee this. See the description of host access types for more information.

#### 6.3.1. Alternate Methods to Signal Fences

Besides submitting a fence to a queue as part of a queue submission command, a fence may also be signaled when a particular event occurs on a device or display.

To create a fence that will be signaled when an event occurs on a device, call:

    VkResult vkRegisterDeviceEventEXT(
        VkDevice                                    device,
        const VkDeviceEventInfoEXT*                 pDeviceEventInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkFence*                                    pFence);

- `device` is a logical device on which the event may occur.

- `pDeviceEventInfo` is a pointer to a VkDeviceEventInfoEXT structure describing the event of interest to the application.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pFence` is a pointer to a handle in which the resulting fence object is returned.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pDeviceEventInfo` must be a valid pointer to a valid VkDeviceEventInfoEXT structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pFence` must be a valid pointer to a VkFence handle

Return Codes

Success

  - `VK_SUCCESS`

The `VkDeviceEventInfoEXT` structure is defined as:

    typedef struct VkDeviceEventInfoEXT {
        VkStructureType         sType;
        const void*             pNext;
        VkDeviceEventTypeEXT    deviceEvent;
    } VkDeviceEventInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `device` is a VkDeviceEventTypeEXT value specifying when the fence will be signaled.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEVICE_EVENT_INFO_EXT`

- `pNext` must be `NULL`

- `deviceEvent` must be a valid VkDeviceEventTypeEXT value

Possible values of VkDeviceEventInfoEXT::`device`, specifying when a fence will be signaled, are:

    typedef enum VkDeviceEventTypeEXT {
        VK_DEVICE_EVENT_TYPE_DISPLAY_HOTPLUG_EXT = 0,
        VK_DEVICE_EVENT_TYPE_MAX_ENUM_EXT = 0x7FFFFFFF
    } VkDeviceEventTypeEXT;

- `VK_DEVICE_EVENT_TYPE_DISPLAY_HOTPLUG_EXT` specifies that the fence is signaled when a display is plugged into or unplugged from the specified device. Applications can use this notification to determine when they need to re-enumerate the available displays on a device.

To create a fence that will be signaled when an event occurs on a VkDisplayKHR object, call:

    VkResult vkRegisterDisplayEventEXT(
        VkDevice                                    device,
        VkDisplayKHR                                display,
        const VkDisplayEventInfoEXT*                pDisplayEventInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkFence*                                    pFence);

- `device` is a logical device associated with `display`

- `display` is the display on which the event may occur.

- `pDisplayEventInfo` is a pointer to a VkDisplayEventInfoEXT structure describing the event of interest to the application.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pFence` is a pointer to a handle in which the resulting fence object is returned.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `display` must be a valid VkDisplayKHR handle

- `pDisplayEventInfo` must be a valid pointer to a valid VkDisplayEventInfoEXT structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pFence` must be a valid pointer to a VkFence handle

- Both of `device`, and `display` must have been created, allocated, or retrieved from the same VkPhysicalDevice

Return Codes

Success

  - `VK_SUCCESS`

The `VkDisplayEventInfoEXT` structure is defined as:

    typedef struct VkDisplayEventInfoEXT {
        VkStructureType          sType;
        const void*              pNext;
        VkDisplayEventTypeEXT    displayEvent;
    } VkDisplayEventInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `displayEvent` is a VkDisplayEventTypeEXT specifying when the fence will be signaled.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DISPLAY_EVENT_INFO_EXT`

- `pNext` must be `NULL`

- `displayEvent` must be a valid VkDisplayEventTypeEXT value

Possible values of VkDisplayEventInfoEXT::`displayEvent`, specifying when a fence will be signaled, are:

    typedef enum VkDisplayEventTypeEXT {
        VK_DISPLAY_EVENT_TYPE_FIRST_PIXEL_OUT_EXT = 0,
        VK_DISPLAY_EVENT_TYPE_MAX_ENUM_EXT = 0x7FFFFFFF
    } VkDisplayEventTypeEXT;

- `VK_DISPLAY_EVENT_TYPE_FIRST_PIXEL_OUT_EXT` specifies that the fence is signaled when the first pixel of the next display refresh cycle leaves the display engine for the display.

#### 6.3.2. Importing Fence Payloads

Applications can import a fence payload into an existing fence using an external fence handle. The effects of the import operation will be either temporary or permanent, as specified by the application. If the import is temporary, the fence will be restored to its permanent state the next time that fence is passed to vkResetFences.

| Note Restoring a fence to its prior permanent payload is a distinct operation from resetting a fence payload. See vkResetFences for more detail.

Performing a subsequent temporary import on a fence before resetting it has no effect on this requirement; the next unsignal of the fence must still restore its last permanent state. A permanent payload import behaves as if the target fence was destroyed, and a new fence was created with the same handle but the imported payload. Because importing a fence payload temporarily or permanently detaches the existing payload from a fence, similar usage restrictions to those applied to `vkDestroyFence` are applied to any command that imports a fence payload. Which of these import types is used is referred to as the import operation’s permanence. Each handle type supports either one or both types of permanence.

The implementation must perform the import operation by either referencing or copying the payload referred to by the specified external fence handle, depending on the handle’s type. The import method used is referred to as the handle type’s transference. When using handle types with reference transference, importing a payload to a fence adds the fence to the set of all fences sharing that payload. This set includes the fence from which the payload was exported. Fence signaling, waiting, and resetting operations performed on any fence in the set must behave as if the set were a single fence. Importing a payload using handle types with copy transference creates a duplicate copy of the payload at the time of import, but makes no further reference to it. Fence signaling, waiting, and resetting operations performed on the target of copy imports must not affect any other fence or payload.

Export operations have the same transference as the specified handle type’s import operations. Additionally, exporting a fence payload to a handle with copy transference has the same side effects on the source fence’s payload as executing a fence reset operation. If the fence was using a temporarily imported payload, the fence’s prior permanent payload will be restored.

| Note The tables Handle Types Supported by VkImportFenceWin32HandleInfoKHR and Handle Types Supported by VkImportFenceFdInfoKHR define the permanence and transference of each handle type.

External synchronization allows implementations to modify an object’s internal state, i.e. payload, without internal synchronization. However, for fences sharing a payload across processes, satisfying the external synchronization requirements of `VkFence` parameters as if all fences in the set were the same object is sometimes infeasible. Satisfying valid usage constraints on the state of a fence would similarly require impractical coordination or levels of trust between processes. Therefore, these constraints only apply to a specific fence handle, not to its payload. For distinct fence objects which share a payload:

- If multiple commands which queue a signal operation, or which unsignal a fence, are called concurrently, behavior will be as if the commands were called in an arbitrary sequential order.

- If a queue submission command is called with a fence that is sharing a payload, and the payload is already associated with another queue command that has not yet completed execution, either one or both of the commands will cause the fence to become signaled when they complete execution.

- If a fence payload is reset while it is associated with a queue command that has not yet completed execution, the payload will become unsignaled, but may become signaled again when the command completes execution.

- In the preceding cases, any of the devices associated with the fences sharing the payload may be lost, or any of the queue submission or fence reset commands may return `VK_ERROR_INITIALIZATION_FAILED`.

Other than these non-deterministic results, behavior is well defined. In particular:

- The implementation must not crash or enter an internally inconsistent state where future valid Vulkan commands might cause undefined results,

- Timeouts on future wait commands on fences sharing the payload must be effective.

| Note These rules allow processes to synchronize access to shared memory without trusting each other. However, such processes must still be cautious not to use the shared fence for more than synchronizing access to the shared memory. For example, a process should not use a fence with shared payload to tell when commands it submitted to a queue have completed and objects used by those commands may be destroyed, since the other process can accidentally or maliciously cause the fence to signal before the commands actually complete.

When a fence is using an imported payload, its VkExportFenceCreateInfo::`handleTypes` value is that specified when creating the fence from which the payload was exported, rather than that specified when creating the fence. Additionally, VkExternalFenceProperties::`exportFromImportedHandleTypes` restricts which handle types can be exported from such a fence based on the specific handle type used to import the current payload. Passing a fence to vkAcquireNextImageKHR is equivalent to temporarily importing a fence payload to that fence.

| Note Because the exportable handle types of an imported fence correspond to its current imported payload, and vkAcquireNextImageKHR behaves the same as a temporary import operation for which the source fence is opaque to the application, applications have no way of determining whether any external handle types can be exported from a fence in this state. Therefore, applications must not attempt to export handles from fences using a temporarily imported payload from vkAcquireNextImageKHR.

When importing a fence payload, it is the responsibility of the application to ensure the external handles meet all valid usage requirements. However, implementations must perform sufficient validation of external handles to ensure that the operation results in a valid fence which will not cause program termination, device loss, queue stalls, host thread stalls, or corruption of other resources when used as allowed according to its import parameters. If the external handle provided does not meet these requirements, the implementation must fail the fence payload import operation with the error code `VK_ERROR_INVALID_EXTERNAL_HANDLE`.

To import a fence payload from a Windows handle, call:

    VkResult vkImportFenceWin32HandleKHR(
        VkDevice                                    device,
        const VkImportFenceWin32HandleInfoKHR*      pImportFenceWin32HandleInfo);

- `device` is the logical device that created the fence.

- `pImportFenceWin32HandleInfo` is a pointer to a VkImportFenceWin32HandleInfoKHR structure specifying the fence and import parameters.

Importing a fence payload from Windows handles does not transfer ownership of the handle to the Vulkan implementation. For handle types defined as NT handles, the application must release ownership using the `CloseHandle` system call when the handle is no longer needed.

Applications can import the same fence payload into multiple instances of Vulkan, into the same instance from which it was exported, and multiple times into a given Vulkan instance.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pImportFenceWin32HandleInfo` must be a valid pointer to a valid VkImportFenceWin32HandleInfoKHR structure

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_INVALID_EXTERNAL_HANDLE`

The `VkImportFenceWin32HandleInfoKHR` structure is defined as:

    typedef struct VkImportFenceWin32HandleInfoKHR {
        VkStructureType                      sType;
        const void*                          pNext;
        VkFence                              fence;
        VkFenceImportFlags                   flags;
        VkExternalFenceHandleTypeFlagBits    handleType;
        HANDLE                               handle;
        LPCWSTR                              name;
    } VkImportFenceWin32HandleInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `fence` is the fence into which the state will be imported.

- `flags` is a bitmask of VkFenceImportFlagBits specifying additional parameters for the fence payload import operation.

- `handleType` specifies the type of `handle`.

- `handle` is the external handle to import, or `NULL`.

- `name` is a null-terminated UTF-16 string naming the underlying synchronization primitive to import, or `NULL`.

The handle types supported by `handleType` are:

Table 6. Handle Types Supported by VkImportFenceWin32HandleInfoKHR
Handle Type | Transference | Permanence Supported
--- | --- | ---
`VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_BIT` | Reference | Temporary,Permanent
`VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT` | Reference | Temporary,Permanent

Valid Usage

- `handleType` must be a value included in the Handle Types Supported by VkImportFenceWin32HandleInfoKHR table.

- If `handleType` is not `VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_BIT`, `name` must be `NULL`.

- If `handleType` is not `0` and `handle` is `NULL`, `name` must name a valid synchronization primitive of the type specified by `handleType`.

- If `handleType` is not `0` and `name` is `NULL`, `handle` must be a valid handle of the type specified by `handleType`.

- If `handle` is not `NULL`, `name` must be `NULL`.

- If `handle` is not `NULL`, it must obey any requirements listed for `handleType` in external fence handle types compatibility.

- If `name` is not `NULL`, it must obey any requirements listed for `handleType` in external fence handle types compatibility.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMPORT_FENCE_WIN32_HANDLE_INFO_KHR`

- `pNext` must be `NULL`

- `fence` must be a valid VkFence handle

- `flags` must be a valid combination of VkFenceImportFlagBits values

- If `handleType` is not `0`, `handleType` must be a valid VkExternalFenceHandleTypeFlagBits value

Host Synchronization

- Host access to `fence` must be externally synchronized

To import a fence payload from a POSIX file descriptor, call:

    VkResult vkImportFenceFdKHR(
        VkDevice                                    device,
        const VkImportFenceFdInfoKHR*               pImportFenceFdInfo);

- `device` is the logical device that created the fence.

- `pImportFenceFdInfo` is a pointer to a VkImportFenceFdInfoKHR structure specifying the fence and import parameters.

Importing a fence payload from a file descriptor transfers ownership of the file descriptor from the application to the Vulkan implementation. The application must not perform any operations on the file descriptor after a successful import.

Applications can import the same fence payload into multiple instances of Vulkan, into the same instance from which it was exported, and multiple times into a given Vulkan instance.

Valid Usage

- `fence` must not be associated with any queue command that has not yet completed execution on that queue

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pImportFenceFdInfo` must be a valid pointer to a valid VkImportFenceFdInfoKHR structure

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_INVALID_EXTERNAL_HANDLE`

The `VkImportFenceFdInfoKHR` structure is defined as:

    typedef struct VkImportFenceFdInfoKHR {
        VkStructureType                      sType;
        const void*                          pNext;
        VkFence                              fence;
        VkFenceImportFlags                   flags;
        VkExternalFenceHandleTypeFlagBits    handleType;
        int                                  fd;
    } VkImportFenceFdInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `fence` is the fence into which the payload will be imported.

- `flags` is a bitmask of VkFenceImportFlagBits specifying additional parameters for the fence payload import operation.

- `handleType` specifies the type of `fd`.

- `fd` is the external handle to import.

The handle types supported by `handleType` are:

Table 7. Handle Types Supported by VkImportFenceFdInfoKHR
Handle Type | Transference | Permanence Supported
--- | --- | ---
`VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_FD_BIT` | Reference | Temporary,Permanent
`VK_EXTERNAL_FENCE_HANDLE_TYPE_SYNC_FD_BIT` | Copy | Temporary

Valid Usage

- `handleType` must be a value included in the Handle Types Supported by VkImportFenceFdInfoKHR table.

- `fd` must obey any requirements listed for `handleType` in external fence handle types compatibility.

If `handleType` is `VK_EXTERNAL_FENCE_HANDLE_TYPE_SYNC_FD_BIT`, the special value `-1` for `fd` is treated like a valid sync file descriptor referring to an object that has already signaled. The import operation will succeed and the `VkFence` will have a temporarily imported payload as if a valid file descriptor had been provided.

| Note This special behavior for importing an invalid sync file descriptor allows easier interoperability with other system APIs which use the convention that an invalid sync file descriptor represents work that has already completed and does not need to be waited for. It is consistent with the option for implementations to return a `-1` file descriptor when exporting a `VK_EXTERNAL_FENCE_HANDLE_TYPE_SYNC_FD_BIT` from a `VkFence` which is signaled.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMPORT_FENCE_FD_INFO_KHR`

- `pNext` must be `NULL`

- `fence` must be a valid VkFence handle

- `flags` must be a valid combination of VkFenceImportFlagBits values

- `handleType` must be a valid VkExternalFenceHandleTypeFlagBits value

Host Synchronization

- Host access to `fence` must be externally synchronized

Bits which can be set in VkImportFenceWin32HandleInfoKHR::`flags` and VkImportFenceFdInfoKHR::`flags` specifying additional parameters of a fence import operation are:

    typedef enum VkFenceImportFlagBits {
        VK_FENCE_IMPORT_TEMPORARY_BIT = 0x00000001,
        VK_FENCE_IMPORT_TEMPORARY_BIT_KHR = VK_FENCE_IMPORT_TEMPORARY_BIT,
        VK_FENCE_IMPORT_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkFenceImportFlagBits;

or the equivalent

    typedef VkFenceImportFlagBits VkFenceImportFlagBitsKHR;

- `VK_FENCE_IMPORT_TEMPORARY_BIT` specifies that the fence payload will be imported only temporarily, as described in Importing Fence Payloads, regardless of the permanence of `handleType`.

    typedef VkFlags VkFenceImportFlags;

or the equivalent

    typedef VkFenceImportFlags VkFenceImportFlagsKHR;

`VkFenceImportFlags` is a bitmask type for setting a mask of zero or more VkFenceImportFlagBits.

### 6.4. Semaphores

Semaphores are a synchronization primitive that can be used to insert a dependency between queue operations or between a queue operation and the host. Binary semaphores have two states - signaled and unsignaled. Timeline semaphores have a monotonically increasing 64-bit unsigned integer payload and are signaled with respect to a particular reference value. A semaphore can be signaled after execution of a queue operation is completed, and a queue operation can wait for a semaphore to become signaled before it begins execution. A timeline semaphore can additionally be signaled from the host with the vkSignalSemaphore command and waited on from the host with the vkWaitSemaphores command.

As with most objects in Vulkan, semaphores are an interface to internal data which is typically opaque to applications. This internal data is referred to as a semaphore’s payload.

However, in order to enable communication with agents outside of the current device, it is necessary to be able to export that payload to a commonly understood format, and subsequently import from that format as well.

The internal data of a semaphore may include a reference to any resources and pending work associated with signal or unsignal operations performed on that semaphore object. Mechanisms to import and export that internal data to and from semaphores are provided below. These mechanisms indirectly enable applications to share semaphore state between two or more semaphores and other synchronization primitives across process and API boundaries.

Semaphores are represented by `VkSemaphore` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkSemaphore)

To create a semaphore, call:

    VkResult vkCreateSemaphore(
        VkDevice                                    device,
        const VkSemaphoreCreateInfo*                pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkSemaphore*                                pSemaphore);

- `device` is the logical device that creates the semaphore.

- `pCreateInfo` is a pointer to a `VkSemaphoreCreateInfo` structure containing information about how the semaphore is to be created.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pSemaphore` is a pointer to a handle in which the resulting semaphore object is returned.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkSemaphoreCreateInfo structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pSemaphore` must be a valid pointer to a VkSemaphore handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkSemaphoreCreateInfo` structure is defined as:

    typedef struct VkSemaphoreCreateInfo {
        VkStructureType           sType;
        const void*               pNext;
        VkSemaphoreCreateFlags    flags;
    } VkSemaphoreCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SEMAPHORE_CREATE_INFO`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkExportSemaphoreCreateInfo, VkExportSemaphoreWin32HandleInfoKHR, or VkSemaphoreTypeCreateInfo

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be `0`

    typedef VkFlags VkSemaphoreCreateFlags;

`VkSemaphoreCreateFlags` is a bitmask type for setting a mask, but is currently reserved for future use.

To create a semaphore of a specific type, add a VkSemaphoreTypeCreateInfo structure to the `pNext` chain of the VkSemaphoreCreateInfo structure. The `VkSemaphoreTypeCreateInfo` structure is defined as:

    typedef struct VkSemaphoreTypeCreateInfo {
        VkStructureType    sType;
        const void*        pNext;
        VkSemaphoreType    semaphoreType;
        uint64_t           initialValue;
    } VkSemaphoreTypeCreateInfo;

or the equivalent

    typedef VkSemaphoreTypeCreateInfo VkSemaphoreTypeCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `semaphoreType` is a VkSemaphoreType value specifying the type of the semaphore.

- `initialValue` is the initial payload value if `semaphoreType` is `VK_SEMAPHORE_TYPE_TIMELINE`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SEMAPHORE_TYPE_CREATE_INFO`

- `semaphoreType` must be a valid VkSemaphoreType value

Valid Usage

- If the `timelineSemaphore` feature is not enabled, `semaphoreType` must not equal `VK_SEMAPHORE_TYPE_TIMELINE`

- If `semaphoreType` is `VK_SEMAPHORE_TYPE_BINARY`, `initialValue` must be zero.

If no `VkSemaphoreTypeCreateInfo` structure is included in the `pNext` chain of VkSemaphoreCreateInfo, then the created semaphore will have a default VkSemaphoreType of `VK_SEMAPHORE_TYPE_BINARY`.

Possible values of VkSemaphoreTypeCreateInfo::`semaphoreType`, specifying the type of a semaphore, are:

    typedef enum VkSemaphoreType {
        VK_SEMAPHORE_TYPE_BINARY = 0,
        VK_SEMAPHORE_TYPE_TIMELINE = 1,
        VK_SEMAPHORE_TYPE_BINARY_KHR = VK_SEMAPHORE_TYPE_BINARY,
        VK_SEMAPHORE_TYPE_TIMELINE_KHR = VK_SEMAPHORE_TYPE_TIMELINE,
        VK_SEMAPHORE_TYPE_MAX_ENUM = 0x7FFFFFFF
    } VkSemaphoreType;

or the equivalent

    typedef VkSemaphoreType VkSemaphoreTypeKHR;

- `VK_SEMAPHORE_TYPE_BINARY` specifies a binary semaphore type that has a boolean payload indicating whether the semaphore is currently signaled or unsignaled. When created, the semaphore is in the unsignaled state.

- `VK_SEMAPHORE_TYPE_TIMELINE` specifies a timeline semaphore type that has a monotonically increasing 64-bit unsigned integer payload indicating whether the semaphore is signaled with respect to a particular reference value. When created, the semaphore payload has the value given by the `initialValue` field of `VkSemaphoreTypeCreateInfo`.

To create a semaphore whose payload can be exported to external handles, add a VkExportSemaphoreCreateInfo structure to the `pNext` chain of the VkSemaphoreCreateInfo structure. The `VkExportSemaphoreCreateInfo` structure is defined as:

    typedef struct VkExportSemaphoreCreateInfo {
        VkStructureType                       sType;
        const void*                           pNext;
        VkExternalSemaphoreHandleTypeFlags    handleTypes;
    } VkExportSemaphoreCreateInfo;

or the equivalent

    typedef VkExportSemaphoreCreateInfo VkExportSemaphoreCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `handleTypes` is a bitmask of VkExternalSemaphoreHandleTypeFlagBits specifying one or more semaphore handle types the application can export from the resulting semaphore. The application can request multiple handle types for the same semaphore.

Valid Usage

- The bits in `handleTypes` must be supported and compatible, as reported by VkExternalSemaphoreProperties.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_EXPORT_SEMAPHORE_CREATE_INFO`

- `handleTypes` must be a valid combination of VkExternalSemaphoreHandleTypeFlagBits values

To specify additional attributes of NT handles exported from a semaphore, add a `VkExportSemaphoreWin32HandleInfoKHR` structure to the `pNext` chain of the VkSemaphoreCreateInfo structure. The `VkExportSemaphoreWin32HandleInfoKHR` structure is defined as:

    typedef struct VkExportSemaphoreWin32HandleInfoKHR {
        VkStructureType               sType;
        const void*                   pNext;
        const SECURITY_ATTRIBUTES*    pAttributes;
        DWORD                         dwAccess;
        LPCWSTR                       name;
    } VkExportSemaphoreWin32HandleInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `pAttributes` is a pointer to a Windows `SECURITY_ATTRIBUTES` structure specifying security attributes of the handle.

- `dwAccess` is a `DWORD` specifying access rights of the handle.

- `name` is a null-terminated UTF-16 string to associate with the underlying synchronization primitive referenced by NT handles exported from the created semaphore.

If VkExportSemaphoreCreateInfo is not present in the same `pNext` chain, this structure is ignored.

If VkExportSemaphoreCreateInfo is present in the `pNext` chain of VkSemaphoreCreateInfo with a Windows `handleType`, but either `VkExportSemaphoreWin32HandleInfoKHR` is not present in the `pNext` chain, or if it is but `pAttributes` is set to `NULL`, default security descriptor values will be used, and child processes created by the application will not inherit the handle, as described in the MSDN documentation for “Synchronization Object Security and Access Rights”1. Further, if the structure is not present, the access rights used depend on the handle type.

For handles of the following types:

`VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_BIT`

The implementation must ensure the access rights allow both signal and wait operations on the semaphore.

For handles of the following types:

`VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D12_FENCE_BIT`

The access rights must be:

`GENERIC_ALL`

1

  https://docs.microsoft.com/en-us/windows/win32/sync/synchronization-object-security-and-access-rights

Valid Usage

- If VkExportSemaphoreCreateInfo::`handleTypes` does not include `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_BIT` or `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D12_FENCE_BIT`, `VkExportSemaphoreWin32HandleInfoKHR` must not be included in the `pNext` chain of VkSemaphoreCreateInfo.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_EXPORT_SEMAPHORE_WIN32_HANDLE_INFO_KHR`

- If `pAttributes` is not `NULL`, `pAttributes` must be a valid pointer to a valid `SECURITY_ATTRIBUTES` value

To export a Windows handle representing the payload of a semaphore, call:

    VkResult vkGetSemaphoreWin32HandleKHR(
        VkDevice                                    device,
        const VkSemaphoreGetWin32HandleInfoKHR*     pGetWin32HandleInfo,
        HANDLE*                                     pHandle);

- `device` is the logical device that created the semaphore being exported.

- `pGetWin32HandleInfo` is a pointer to a VkSemaphoreGetWin32HandleInfoKHR structure containing parameters of the export operation.

- `pHandle` will return the Windows handle representing the semaphore state.

For handle types defined as NT handles, the handles returned by `vkGetSemaphoreWin32HandleKHR` are owned by the application. To avoid leaking resources, the application must release ownership of them using the `CloseHandle` system call when they are no longer needed.

Exporting a Windows handle from a semaphore may have side effects depending on the transference of the specified handle type, as described in Importing Semaphore Payloads.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pGetWin32HandleInfo` must be a valid pointer to a valid VkSemaphoreGetWin32HandleInfoKHR structure

- `pHandle` must be a valid pointer to a `HANDLE` value

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_TOO_MANY_OBJECTS`

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

The `VkSemaphoreGetWin32HandleInfoKHR` structure is defined as:

    typedef struct VkSemaphoreGetWin32HandleInfoKHR {
        VkStructureType                          sType;
        const void*                              pNext;
        VkSemaphore                              semaphore;
        VkExternalSemaphoreHandleTypeFlagBits    handleType;
    } VkSemaphoreGetWin32HandleInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `semaphore` is the semaphore from which state will be exported.

- `handleType` is the type of handle requested.

The properties of the handle returned depend on the value of `handleType`. See VkExternalSemaphoreHandleTypeFlagBits for a description of the properties of the defined external semaphore handle types.

Valid Usage

- `handleType` must have been included in VkExportSemaphoreCreateInfo::`handleTypes` when the `semaphore`’s current payload was created.

- If `handleType` is defined as an NT handle, vkGetSemaphoreWin32HandleKHR must be called no more than once for each valid unique combination of `semaphore` and `handleType`.

- `semaphore` must not currently have its payload replaced by an imported payload as described below in Importing Semaphore Payloads unless that imported payload’s handle type was included in VkExternalSemaphoreProperties::`exportFromImportedHandleTypes` for `handleType`.

- If `handleType` refers to a handle type with copy payload transference semantics, as defined below in Importing Semaphore Payloads, there must be no queue waiting on `semaphore`.

- If `handleType` refers to a handle type with copy payload transference semantics, `semaphore` must be signaled, or have an associated semaphore signal operation pending execution.

- `handleType` must be defined as an NT handle or a global share handle.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SEMAPHORE_GET_WIN32_HANDLE_INFO_KHR`

- `pNext` must be `NULL`

- `semaphore` must be a valid VkSemaphore handle

- `handleType` must be a valid VkExternalSemaphoreHandleTypeFlagBits value

To export a POSIX file descriptor representing the payload of a semaphore, call:

    VkResult vkGetSemaphoreFdKHR(
        VkDevice                                    device,
        const VkSemaphoreGetFdInfoKHR*              pGetFdInfo,
        int*                                        pFd);

- `device` is the logical device that created the semaphore being exported.

- `pGetFdInfo` is a pointer to a VkSemaphoreGetFdInfoKHR structure containing parameters of the export operation.

- `pFd` will return the file descriptor representing the semaphore payload.

Each call to `vkGetSemaphoreFdKHR` must create a new file descriptor and transfer ownership of it to the application. To avoid leaking resources, the application must release ownership of the file descriptor when it is no longer needed.

| Note Ownership can be released in many ways. For example, the application can call `close`() on the file descriptor, or transfer ownership back to Vulkan by using the file descriptor to import a semaphore payload.

Where supported by the operating system, the implementation must set the file descriptor to be closed automatically when an `execve` system call is made.

Exporting a file descriptor from a semaphore may have side effects depending on the transference of the specified handle type, as described in Importing Semaphore State.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pGetFdInfo` must be a valid pointer to a valid VkSemaphoreGetFdInfoKHR structure

- `pFd` must be a valid pointer to an `int` value

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_TOO_MANY_OBJECTS`

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

The `VkSemaphoreGetFdInfoKHR` structure is defined as:

    typedef struct VkSemaphoreGetFdInfoKHR {
        VkStructureType                          sType;
        const void*                              pNext;
        VkSemaphore                              semaphore;
        VkExternalSemaphoreHandleTypeFlagBits    handleType;
    } VkSemaphoreGetFdInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `semaphore` is the semaphore from which state will be exported.

- `handleType` is the type of handle requested.

The properties of the file descriptor returned depend on the value of `handleType`. See VkExternalSemaphoreHandleTypeFlagBits for a description of the properties of the defined external semaphore handle types.

Valid Usage

- `handleType` must have been included in VkExportSemaphoreCreateInfo::`handleTypes` when `semaphore`’s current payload was created.

- `semaphore` must not currently have its payload replaced by an imported payload as described below in Importing Semaphore Payloads unless that imported payload’s handle type was included in VkExternalSemaphoreProperties::`exportFromImportedHandleTypes` for `handleType`.

- If `handleType` refers to a handle type with copy payload transference semantics, as defined below in Importing Semaphore Payloads, there must be no queue waiting on `semaphore`.

- If `handleType` refers to a handle type with copy payload transference semantics, `semaphore` must be signaled, or have an associated semaphore signal operation pending execution.

- `handleType` must be defined as a POSIX file descriptor handle.

- If `handleType` refers to a handle type with copy payload transference semantics, `semaphore` must have been created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_BINARY`.

- If `handleType` refers to a handle type with copy payload transference semantics, `semaphore` must have an associated semaphore signal operation that has been submitted for execution and any semaphore signal operations on which it depends (if any) must have also been submitted for execution.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SEMAPHORE_GET_FD_INFO_KHR`

- `pNext` must be `NULL`

- `semaphore` must be a valid VkSemaphore handle

- `handleType` must be a valid VkExternalSemaphoreHandleTypeFlagBits value

To destroy a semaphore, call:

    void vkDestroySemaphore(
        VkDevice                                    device,
        VkSemaphore                                 semaphore,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that destroys the semaphore.

- `semaphore` is the handle of the semaphore to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage

- All submitted batches that refer to `semaphore` must have completed execution

- If `VkAllocationCallbacks` were provided when `semaphore` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `semaphore` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `semaphore` is not VK_NULL_HANDLE, `semaphore` must be a valid VkSemaphore handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- If `semaphore` is a valid handle, it must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `semaphore` must be externally synchronized

#### 6.4.1. Semaphore Signaling

When a batch is submitted to a queue via a queue submission, and it includes semaphores to be signaled, it defines a memory dependency on the batch, and defines semaphore signal operations which set the semaphores to the signaled state.

In case of semaphores created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE` the semaphore is considered signaled with respect to the counter value set to be signaled as specified in VkTimelineSemaphoreSubmitInfo or VkSemaphoreSignalInfo.

The first synchronization scope includes every command submitted in the same batch. Semaphore signal operations that are defined by vkQueueSubmit additionally include all commands that occur earlier in submission order. Semaphore signal operations that are defined by vkQueueSubmit or vkQueueBindSparse additionally include in the first synchronization scope any semaphore and fence signal operations that occur earlier in signal operation order.

The second synchronization scope includes only the semaphore signal operation.

The first access scope includes all memory access performed by the device.

The second access scope is empty.

#### 6.4.2. Semaphore Waiting

When a batch is submitted to a queue via a queue submission, and it includes semaphores to be waited on, it defines a memory dependency between prior semaphore signal operations and the batch, and defines semaphore wait operations.

Such semaphore wait operations set the semaphores created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_BINARY` to the unsignaled state. In case of semaphores created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE` a prior semaphore signal operation defines a memory dependency with a semaphore wait operation if the value the semaphore is signaled with is greater than or equal to the value the semaphore is waited with, thus the semaphore will continue to be considered signaled with respect to the counter value waited on as specified in VkTimelineSemaphoreSubmitInfo.

The first synchronization scope includes all semaphore signal operations that operate on semaphores waited on in the same batch, and that happen-before the wait completes.

The second synchronization scope includes every command submitted in the same batch. In the case of vkQueueSubmit, the second synchronization scope is limited to operations on the pipeline stages determined by the destination stage mask specified by the corresponding element of `pWaitDstStageMask`. Also, in the case of vkQueueSubmit, the second synchronization scope additionally includes all commands that occur later in submission order.

The first access scope is empty.

The second access scope includes all memory access performed by the device.

The semaphore wait operation happens-after the first set of operations in the execution dependency, and happens-before the second set of operations in the execution dependency.

| Note Unlike timeline semaphores, fences or events, the act of waiting for a binary semaphore also unsignals that semaphore. Applications must ensure that between two such wait operations, the semaphore is signaled again, with execution dependencies used to ensure these occur in order. Binary semaphore waits and signals should thus occur in discrete 1:1 pairs.

| Note A common scenario for using `pWaitDstStageMask` with values other than `VK_PIPELINE_STAGE_ALL_COMMANDS_BIT` is when synchronizing a window system presentation operation against subsequent command buffers which render the next frame. In this case, a presentation image must not be overwritten until the presentation operation completes, but other pipeline stages can execute without waiting. A mask of `VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT` prevents subsequent color attachment writes from executing until the semaphore signals. Some implementations may be able to execute transfer operations and/or vertex processing work before the semaphore is signaled. If an image layout transition needs to be performed on a presentable image before it is used in a framebuffer, that can be performed as the first operation submitted to the queue after acquiring the image, and should not prevent other work from overlapping with the presentation operation. For example, a `VkImageMemoryBarrier` could use: `srcStageMask` = `VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT` `srcAccessMask` = 0 `dstStageMask` = `VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT` `dstAccessMask` = `VK_ACCESS_COLOR_ATTACHMENT_READ_BIT` | `VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT`. `oldLayout` = `VK_IMAGE_LAYOUT_PRESENT_SRC_KHR` `newLayout` = `VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL` Alternatively, `oldLayout` can be `VK_IMAGE_LAYOUT_UNDEFINED`, if the image’s contents need not be preserved. This barrier accomplishes a dependency chain between previous presentation operations and subsequent color attachment output operations, with the layout transition performed in between, and does not introduce a dependency between previous work and any vertex processing stages. More precisely, the semaphore signals after the presentation operation completes, the semaphore wait stalls the `VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT` stage, and there is a dependency from that same stage to itself with the layout transition performed in between.

#### 6.4.3. Semaphore State Requirements For Wait Operations

Before waiting on a semaphore, the application must ensure the semaphore is in a valid state for a wait operation. Specifically, when a semaphore wait operation is submitted to a queue:

- A binary semaphore must be signaled, or have an associated semaphore signal operation that is pending execution.

- Any semaphore signal operations on which the pending binary semaphore signal operation depends must also be completed or pending execution.

- There must be no other queue waiting on the same binary semaphore when the operation executes.

#### 6.4.4. Host Operations on Semaphores

In addition to semaphore signal operations and semaphore wait operations submitted to device queues, timeline semaphores support the following host operations:

- Query the current counter value of the semaphore using the vkGetSemaphoreCounterValue command.

- Wait for a set of semaphores to reach particular counter values using the vkWaitSemaphores command.

- Signal the semaphore with a particular counter value from the host using the vkSignalSemaphore command.

To query the current counter value of a semaphore created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE` from the host, call:

    VkResult vkGetSemaphoreCounterValue(
        VkDevice                                    device,
        VkSemaphore                                 semaphore,
        uint64_t*                                   pValue);

or the equivalent command

    VkResult vkGetSemaphoreCounterValueKHR(
        VkDevice                                    device,
        VkSemaphore                                 semaphore,
        uint64_t*                                   pValue);

- `device` is the logical device that owns the semaphore.

- `semaphore` is the handle of the semaphore to query.

- `pValue` is a pointer to a 64-bit integer value in which the current counter value of the semaphore is returned.

| Note If a queue submission command is pending execution, then the value returned by this command may immediately be out of date.

Valid Usage

- `semaphore` must have been created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `semaphore` must be a valid VkSemaphore handle

- `pValue` must be a valid pointer to a `uint64_t` value

- `semaphore` must have been created, allocated, or retrieved from `device`

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_DEVICE_LOST`

To wait for a set of semaphores created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE` to reach particular counter values on the host, call:

    VkResult vkWaitSemaphores(
        VkDevice                                    device,
        const VkSemaphoreWaitInfo*                  pWaitInfo,
        uint64_t                                    timeout);

or the equivalent command

    VkResult vkWaitSemaphoresKHR(
        VkDevice                                    device,
        const VkSemaphoreWaitInfo*                  pWaitInfo,
        uint64_t                                    timeout);

- `device` is the logical device that owns the semaphore.

- `pWaitInfo` is a pointer to a VkSemaphoreWaitInfo structure containing information about the wait condition.

- `timeout` is the timeout period in units of nanoseconds. `timeout` is adjusted to the closest value allowed by the implementation-dependent timeout accuracy, which may be substantially longer than one nanosecond, and may be longer than the requested period.

If the condition is satisfied when `vkWaitSemaphores` is called, then `vkWaitSemaphores` returns immediately. If the condition is not satisfied at the time `vkWaitSemaphores` is called, then `vkWaitSemaphores` will block and wait up to `timeout` nanoseconds for the condition to become satisfied.

If `timeout` is zero, then `vkWaitSemaphores` does not wait, but simply returns information about the current state of the semaphore. `VK_TIMEOUT` will be returned in this case if the condition is not satisfied, even though no actual wait was performed.

If the specified timeout period expires before the condition is satisfied, `vkWaitSemaphores` returns `VK_TIMEOUT`. If the condition is satisfied before `timeout` nanoseconds has expired, `vkWaitSemaphores` returns `VK_SUCCESS`.

If device loss occurs (see Lost Device) before the timeout has expired, `vkWaitSemaphores` must return in finite time with either `VK_SUCCESS` or `VK_ERROR_DEVICE_LOST`.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pWaitInfo` must be a valid pointer to a valid VkSemaphoreWaitInfo structure

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_TIMEOUT`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_DEVICE_LOST`

The `VkSemaphoreWaitInfo` structure is defined as:

    typedef struct VkSemaphoreWaitInfo {
        VkStructureType         sType;
        const void*             pNext;
        VkSemaphoreWaitFlags    flags;
        uint32_t                semaphoreCount;
        const VkSemaphore*      pSemaphores;
        const uint64_t*         pValues;
    } VkSemaphoreWaitInfo;

or the equivalent

    typedef VkSemaphoreWaitInfo VkSemaphoreWaitInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkSemaphoreWaitFlagBits specifying additional parameters for the semaphore wait operation.

- `semaphoreCount` is the number of semaphores to wait on.

- `pSemaphores` is a pointer to an array of `semaphoreCount` semaphore handles to wait on.

- `pValues` is a pointer to an array of `semaphoreCount` timeline semaphore values.

Valid Usage

- All of the elements of `pSemaphores` must reference a semaphore that was created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SEMAPHORE_WAIT_INFO`

- `pNext` must be `NULL`

- `flags` must be a valid combination of VkSemaphoreWaitFlagBits values

- `pSemaphores` must be a valid pointer to an array of `semaphoreCount` valid VkSemaphore handles

- `pValues` must be a valid pointer to an array of `semaphoreCount` `uint64_t` values

- `semaphoreCount` must be greater than `0`

Bits which can be set in VkSemaphoreWaitInfo::`flags`, specifying additional parameters of a semaphore wait operation, are:

    typedef enum VkSemaphoreWaitFlagBits {
        VK_SEMAPHORE_WAIT_ANY_BIT = 0x00000001,
        VK_SEMAPHORE_WAIT_ANY_BIT_KHR = VK_SEMAPHORE_WAIT_ANY_BIT,
        VK_SEMAPHORE_WAIT_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkSemaphoreWaitFlagBits;

or the equivalent

    typedef VkSemaphoreWaitFlagBits VkSemaphoreWaitFlagBitsKHR;

- `VK_SEMAPHORE_WAIT_ANY_BIT` specifies that the semaphore wait condition is that at least one of the semaphores in `VkSemaphoreWaitInfo`::`pSemaphores` has reached the value specified by the corresponding element of `VkSemaphoreWaitInfo`::`pValues`. If `VK_SEMAPHORE_WAIT_ANY_BIT` is not set, the semaphore wait condition is that all of the semaphores in `VkSemaphoreWaitInfo`::`pSemaphores` have reached the value specified by the corresponding element of `VkSemaphoreWaitInfo`::`pValues`.

    typedef VkFlags VkSemaphoreWaitFlags;

or the equivalent

    typedef VkSemaphoreWaitFlags VkSemaphoreWaitFlagsKHR;

`VkSemaphoreWaitFlags` is a bitmask type for setting a mask of zero or more VkSemaphoreWaitFlagBits.

To signal a semaphore created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE` with a particular counter value, on the host, call:

    VkResult vkSignalSemaphore(
        VkDevice                                    device,
        const VkSemaphoreSignalInfo*                pSignalInfo);

or the equivalent command

    VkResult vkSignalSemaphoreKHR(
        VkDevice                                    device,
        const VkSemaphoreSignalInfo*                pSignalInfo);

- `device` is the logical device that owns the semaphore.

- `pSignalInfo` is a pointer to a VkSemaphoreSignalInfo structure containing information about the signal operation.

When `vkSignalSemaphore` is executed on the host, it defines and immediately executes a semaphore signal operation which sets the timeline semaphore to the given value.

The first synchronization scope is defined by the host execution model, but includes execution of `vkSignalSemaphore` on the host and anything that happened-before it.

The second synchronization scope is empty.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pSignalInfo` must be a valid pointer to a valid VkSemaphoreSignalInfo structure

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkSemaphoreSignalInfo` structure is defined as:

    typedef struct VkSemaphoreSignalInfo {
        VkStructureType    sType;
        const void*        pNext;
        VkSemaphore        semaphore;
        uint64_t           value;
    } VkSemaphoreSignalInfo;

or the equivalent

    typedef VkSemaphoreSignalInfo VkSemaphoreSignalInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `semaphore` is the handle of the semaphore to signal.

- `value` is the value to signal.

Valid Usage

- `semaphore` must have been created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE`

- `value` must have a value greater than the current value of the semaphore

- `value` must be less than the value of any pending semaphore signal operations

- `value` must have a value which does not differ from the current value of the semaphore or the value of any outstanding semaphore wait or signal operation on `semaphore` by more than `maxTimelineSemaphoreValueDifference`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SEMAPHORE_SIGNAL_INFO`

- `pNext` must be `NULL`

- `semaphore` must be a valid VkSemaphore handle

#### 6.4.5. Importing Semaphore Payloads

Applications can import a semaphore payload into an existing semaphore using an external semaphore handle. The effects of the import operation will be either temporary or permanent, as specified by the application. If the import is temporary, the implementation must restore the semaphore to its prior permanent state after submitting the next semaphore wait operation. Performing a subsequent temporary import on a semaphore before performing a semaphore wait has no effect on this requirement; the next wait submitted on the semaphore must still restore its last permanent state. A permanent payload import behaves as if the target semaphore was destroyed, and a new semaphore was created with the same handle but the imported payload. Because importing a semaphore payload temporarily or permanently detaches the existing payload from a semaphore, similar usage restrictions to those applied to `vkDestroySemaphore` are applied to any command that imports a semaphore payload. Which of these import types is used is referred to as the import operation’s permanence. Each handle type supports either one or both types of permanence.

The implementation must perform the import operation by either referencing or copying the payload referred to by the specified external semaphore handle, depending on the handle’s type. The import method used is referred to as the handle type’s transference. When using handle types with reference transference, importing a payload to a semaphore adds the semaphore to the set of all semaphores sharing that payload. This set includes the semaphore from which the payload was exported. Semaphore signaling and waiting operations performed on any semaphore in the set must behave as if the set were a single semaphore. Importing a payload using handle types with copy transference creates a duplicate copy of the payload at the time of import, but makes no further reference to it. Semaphore signaling and waiting operations performed on the target of copy imports must not affect any other semaphore or payload.

Export operations have the same transference as the specified handle type’s import operations. Additionally, exporting a semaphore payload to a handle with copy transference has the same side effects on the source semaphore’s payload as executing a semaphore wait operation. If the semaphore was using a temporarily imported payload, the semaphore’s prior permanent payload will be restored.

| Note The tables Handle Types Supported by VkImportSemaphoreWin32HandleInfoKHR and Handle Types Supported by VkImportSemaphoreFdInfoKHR define the permanence and transference of each handle type.

External synchronization allows implementations to modify an object’s internal state, i.e. payload, without internal synchronization. However, for semaphores sharing a payload across processes, satisfying the external synchronization requirements of `VkSemaphore` parameters as if all semaphores in the set were the same object is sometimes infeasible. Satisfying the wait operation state requirements would similarly require impractical coordination or levels of trust between processes. Therefore, these constraints only apply to a specific semaphore handle, not to its payload. For distinct semaphore objects which share a payload, if the semaphores are passed to separate queue submission commands concurrently, behavior will be as if the commands were called in an arbitrary sequential order. If the wait operation state requirements are violated for the shared payload by a queue submission command, or if a signal operation is queued for a shared payload that is already signaled or has a pending signal operation, effects must be limited to one or more of the following:

- Returning `VK_ERROR_INITIALIZATION_FAILED` from the command which resulted in the violation.

- Losing the logical device on which the violation occurred immediately or at a future time, resulting in a `VK_ERROR_DEVICE_LOST` error from subsequent commands, including the one causing the violation.

- Continuing execution of the violating command or operation as if the semaphore wait completed successfully after an implementation-dependent timeout. In this case, the state of the payload becomes undefined, and future operations on semaphores sharing the payload will be subject to these same rules. The semaphore must be destroyed or have its payload replaced by an import operation to again have a well-defined state.

| Note These rules allow processes to synchronize access to shared memory without trusting each other. However, such processes must still be cautious not to use the shared semaphore for more than synchronizing access to the shared memory. For example, a process should not use a shared semaphore as part of an execution dependency chain that, when complete, leads to objects being destroyed, if it does not trust other processes sharing the semaphore payload.

When a semaphore is using an imported payload, its VkExportSemaphoreCreateInfo::`handleTypes` value is that specified when creating the semaphore from which the payload was exported, rather than that specified when creating the semaphore. Additionally, VkExternalSemaphoreProperties::`exportFromImportedHandleTypes` restricts which handle types can be exported from such a semaphore based on the specific handle type used to import the current payload. Passing a semaphore to vkAcquireNextImageKHR is equivalent to temporarily importing a semaphore payload to that semaphore.

| Note Because the exportable handle types of an imported semaphore correspond to its current imported payload, and vkAcquireNextImageKHR behaves the same as a temporary import operation for which the source semaphore is opaque to the application, applications have no way of determining whether any external handle types can be exported from a semaphore in this state. Therefore, applications must not attempt to export external handles from semaphores using a temporarily imported payload from vkAcquireNextImageKHR.

When importing a semaphore payload, it is the responsibility of the application to ensure the external handles meet all valid usage requirements. However, implementations must perform sufficient validation of external handles to ensure that the operation results in a valid semaphore which will not cause program termination, device loss, queue stalls, or corruption of other resources when used as allowed according to its import parameters, and excepting those side effects allowed for violations of the valid semaphore state for wait operations rules. If the external handle provided does not meet these requirements, the implementation must fail the semaphore payload import operation with the error code `VK_ERROR_INVALID_EXTERNAL_HANDLE`.

In addition, when importing a semaphore payload that is not compatible with the payload type corresponding to the VkSemaphoreType the semaphore was created with, the implementation may fail the semaphore payload import operation with the error code `VK_ERROR_INVALID_EXTERNAL_HANDLE`.

| Note As the introduction of the external semaphore handle type `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D12_FENCE_BIT` predates that of timeline semaphores, support for importing semaphore payloads from external handles of that type into semaphores created (implicitly or explicitly) with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_BINARY` is preserved for backwards compatibility. However, applications should prefer importing such handle types into semaphores created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE`.

To import a semaphore payload from a Windows handle, call:

    VkResult vkImportSemaphoreWin32HandleKHR(
        VkDevice                                    device,
        const VkImportSemaphoreWin32HandleInfoKHR*  pImportSemaphoreWin32HandleInfo);

- `device` is the logical device that created the semaphore.

- `pImportSemaphoreWin32HandleInfo` is a pointer to a VkImportSemaphoreWin32HandleInfoKHR structure specifying the semaphore and import parameters.

Importing a semaphore payload from Windows handles does not transfer ownership of the handle to the Vulkan implementation. For handle types defined as NT handles, the application must release ownership using the `CloseHandle` system call when the handle is no longer needed.

Applications can import the same semaphore payload into multiple instances of Vulkan, into the same instance from which it was exported, and multiple times into a given Vulkan instance.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pImportSemaphoreWin32HandleInfo` must be a valid pointer to a valid VkImportSemaphoreWin32HandleInfoKHR structure

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_INVALID_EXTERNAL_HANDLE`

The `VkImportSemaphoreWin32HandleInfoKHR` structure is defined as:

    typedef struct VkImportSemaphoreWin32HandleInfoKHR {
        VkStructureType                          sType;
        const void*                              pNext;
        VkSemaphore                              semaphore;
        VkSemaphoreImportFlags                   flags;
        VkExternalSemaphoreHandleTypeFlagBits    handleType;
        HANDLE                                   handle;
        LPCWSTR                                  name;
    } VkImportSemaphoreWin32HandleInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `semaphore` is the semaphore into which the payload will be imported.

- `flags` is a bitmask of VkSemaphoreImportFlagBits specifying additional parameters for the semaphore payload import operation.

- `handleType` specifies the type of `handle`.

- `handle` is the external handle to import, or `NULL`.

- `name` is a null-terminated UTF-16 string naming the underlying synchronization primitive to import, or `NULL`.

The handle types supported by `handleType` are:

Table 8. Handle Types Supported by VkImportSemaphoreWin32HandleInfoKHR
Handle Type | Transference | Permanence Supported
--- | --- | ---
`VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_BIT` | Reference | Temporary,Permanent
`VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT` | Reference | Temporary,Permanent
`VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D12_FENCE_BIT` | Reference | Temporary,Permanent

Valid Usage

- `handleType` must be a value included in the Handle Types Supported by VkImportSemaphoreWin32HandleInfoKHR table.

- If `handleType` is not `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_BIT` or `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D12_FENCE_BIT`, `name` must be `NULL`.

- If `handleType` is not `0` and `handle` is `NULL`, `name` must name a valid synchronization primitive of the type specified by `handleType`.

- If `handleType` is not `0` and `name` is `NULL`, `handle` must be a valid handle of the type specified by `handleType`.

- If `handle` is not `NULL`, `name` must be `NULL`.

- If `handle` is not `NULL`, it must obey any requirements listed for `handleType` in external semaphore handle types compatibility.

- If `name` is not `NULL`, it must obey any requirements listed for `handleType` in external semaphore handle types compatibility.

- If `handleType` is `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_BIT` or `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT`, the VkSemaphoreCreateInfo::`flags` field must match that of the semaphore from which `handle` or `name` was exported.

- If `handleType` is `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_BIT` or `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT`, the VkSemaphoreTypeCreateInfo::`semaphoreType` field must match that of the semaphore from which `handle` or `name` was exported.

- If `flags` contains `VK_SEMAPHORE_IMPORT_TEMPORARY_BIT`, the VkSemaphoreTypeCreateInfo::`semaphoreType` field of the semaphore from which `handle` or `name` was exported must not be `VK_SEMAPHORE_TYPE_TIMELINE`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMPORT_SEMAPHORE_WIN32_HANDLE_INFO_KHR`

- `pNext` must be `NULL`

- `semaphore` must be a valid VkSemaphore handle

- `flags` must be a valid combination of VkSemaphoreImportFlagBits values

- If `handleType` is not `0`, `handleType` must be a valid VkExternalSemaphoreHandleTypeFlagBits value

Host Synchronization

- Host access to `semaphore` must be externally synchronized

To import a semaphore payload from a POSIX file descriptor, call:

    VkResult vkImportSemaphoreFdKHR(
        VkDevice                                    device,
        const VkImportSemaphoreFdInfoKHR*           pImportSemaphoreFdInfo);

- `device` is the logical device that created the semaphore.

- `pImportSemaphoreFdInfo` is a pointer to a VkImportSemaphoreFdInfoKHR structure specifying the semaphore and import parameters.

Importing a semaphore payload from a file descriptor transfers ownership of the file descriptor from the application to the Vulkan implementation. The application must not perform any operations on the file descriptor after a successful import.

Applications can import the same semaphore payload into multiple instances of Vulkan, into the same instance from which it was exported, and multiple times into a given Vulkan instance.

Valid Usage

- `semaphore` must not be associated with any queue command that has not yet completed execution on that queue

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pImportSemaphoreFdInfo` must be a valid pointer to a valid VkImportSemaphoreFdInfoKHR structure

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_INVALID_EXTERNAL_HANDLE`

The `VkImportSemaphoreFdInfoKHR` structure is defined as:

    typedef struct VkImportSemaphoreFdInfoKHR {
        VkStructureType                          sType;
        const void*                              pNext;
        VkSemaphore                              semaphore;
        VkSemaphoreImportFlags                   flags;
        VkExternalSemaphoreHandleTypeFlagBits    handleType;
        int                                      fd;
    } VkImportSemaphoreFdInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `semaphore` is the semaphore into which the payload will be imported.

- `flags` is a bitmask of VkSemaphoreImportFlagBits specifying additional parameters for the semaphore payload import operation.

- `handleType` specifies the type of `fd`.

- `fd` is the external handle to import.

The handle types supported by `handleType` are:

Table 9. Handle Types Supported by VkImportSemaphoreFdInfoKHR
Handle Type | Transference | Permanence Supported
--- | --- | ---
`VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_FD_BIT` | Reference | Temporary,Permanent
`VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BIT` | Copy | Temporary

Valid Usage

- `handleType` must be a value included in the Handle Types Supported by VkImportSemaphoreFdInfoKHR table.

- `fd` must obey any requirements listed for `handleType` in external semaphore handle types compatibility.

- If `handleType` is `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_FD_BIT`, the VkSemaphoreCreateInfo::`flags` field must match that of the semaphore from which `fd` was exported.

- If `handleType` is `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_FD_BIT`, the VkSemaphoreTypeCreateInfo::`semaphoreType` field must match that of the semaphore from which `fd` was exported.

- If `flags` contains `VK_SEMAPHORE_IMPORT_TEMPORARY_BIT`, the VkSemaphoreTypeCreateInfo::`semaphoreType` field of the semaphore from which `fd` was exported must not be `VK_SEMAPHORE_TYPE_TIMELINE`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMPORT_SEMAPHORE_FD_INFO_KHR`

- `pNext` must be `NULL`

- `semaphore` must be a valid VkSemaphore handle

- `flags` must be a valid combination of VkSemaphoreImportFlagBits values

- `handleType` must be a valid VkExternalSemaphoreHandleTypeFlagBits value

Host Synchronization

- Host access to `semaphore` must be externally synchronized

Additional parameters of a semaphore import operation are specified by VkImportSemaphoreWin32HandleInfoKHR::`flags` or VkImportSemaphoreFdInfoKHR::`flags` . Bits which can be set include:

    typedef enum VkSemaphoreImportFlagBits {
        VK_SEMAPHORE_IMPORT_TEMPORARY_BIT = 0x00000001,
        VK_SEMAPHORE_IMPORT_TEMPORARY_BIT_KHR = VK_SEMAPHORE_IMPORT_TEMPORARY_BIT,
        VK_SEMAPHORE_IMPORT_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkSemaphoreImportFlagBits;

or the equivalent

    typedef VkSemaphoreImportFlagBits VkSemaphoreImportFlagBitsKHR;

These bits have the following meanings:

- `VK_SEMAPHORE_IMPORT_TEMPORARY_BIT` specifies that the semaphore payload will be imported only temporarily, as described in Importing Semaphore Payloads, regardless of the permanence of `handleType`.

    typedef VkFlags VkSemaphoreImportFlags;

or the equivalent

    typedef VkSemaphoreImportFlags VkSemaphoreImportFlagsKHR;

`VkSemaphoreImportFlags` is a bitmask type for setting a mask of zero or more VkSemaphoreImportFlagBits.

### 6.5. Events

Events are a synchronization primitive that can be used to insert a fine-grained dependency between commands submitted to the same queue, or between the host and a queue. Events must not be used to insert a dependency between commands submitted to different queues. Events have two states - signaled and unsignaled. An application can signal or unsignal an event either on the host or on the device. A device can be made to wait for an event to become signaled before executing further operations. No command exists to wait for an event to become signaled on the host, but the current state of an event can be queried.

Events are represented by `VkEvent` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkEvent)

To create an event, call:

    VkResult vkCreateEvent(
        VkDevice                                    device,
        const VkEventCreateInfo*                    pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkEvent*                                    pEvent);

- `device` is the logical device that creates the event.

- `pCreateInfo` is a pointer to a `VkEventCreateInfo` structure containing information about how the event is to be created.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pEvent` is a pointer to a handle in which the resulting event object is returned.

When created, the event object is in the unsignaled state.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkEventCreateInfo structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pEvent` must be a valid pointer to a VkEvent handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkEventCreateInfo` structure is defined as:

    typedef struct VkEventCreateInfo {
        VkStructureType       sType;
        const void*           pNext;
        VkEventCreateFlags    flags;
    } VkEventCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_EVENT_CREATE_INFO`

- `pNext` must be `NULL`

- `flags` must be `0`

    typedef VkFlags VkEventCreateFlags;

`VkEventCreateFlags` is a bitmask type for setting a mask, but is currently reserved for future use.

To destroy an event, call:

    void vkDestroyEvent(
        VkDevice                                    device,
        VkEvent                                     event,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that destroys the event.

- `event` is the handle of the event to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage

- All submitted commands that refer to `event` must have completed execution

- If `VkAllocationCallbacks` were provided when `event` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `event` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `event` is not VK_NULL_HANDLE, `event` must be a valid VkEvent handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- If `event` is a valid handle, it must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `event` must be externally synchronized

To query the state of an event from the host, call:

    VkResult vkGetEventStatus(
        VkDevice                                    device,
        VkEvent                                     event);

- `device` is the logical device that owns the event.

- `event` is the handle of the event to query.

Upon success, `vkGetEventStatus` returns the state of the event object with the following return codes:

Table 10. Event Object Status Codes
Status | Meaning
--- | ---
`VK_EVENT_SET` | The event specified by `event` is signaled.
`VK_EVENT_RESET` | The event specified by `event` is unsignaled.

If a `vkCmdSetEvent` or `vkCmdResetEvent` command is in a command buffer that is in the pending state, then the value returned by this command may immediately be out of date.

The state of an event can be updated by the host. The state of the event is immediately changed, and subsequent calls to `vkGetEventStatus` will return the new state. If an event is already in the requested state, then updating it to the same state has no effect.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `event` must be a valid VkEvent handle

- `event` must have been created, allocated, or retrieved from `device`

Return Codes

Success

  - `VK_EVENT_SET`

  - `VK_EVENT_RESET`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_DEVICE_LOST`

To set the state of an event to signaled from the host, call:

    VkResult vkSetEvent(
        VkDevice                                    device,
        VkEvent                                     event);

- `device` is the logical device that owns the event.

- `event` is the event to set.

When vkSetEvent is executed on the host, it defines an event signal operation which sets the event to the signaled state.

If `event` is already in the signaled state when vkSetEvent is executed, then vkSetEvent has no effect, and no event signal operation occurs.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `event` must be a valid VkEvent handle

- `event` must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `event` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

To set the state of an event to unsignaled from the host, call:

    VkResult vkResetEvent(
        VkDevice                                    device,
        VkEvent                                     event);

- `device` is the logical device that owns the event.

- `event` is the event to reset.

When vkResetEvent is executed on the host, it defines an event unsignal operation which resets the event to the unsignaled state.

If `event` is already in the unsignaled state when vkResetEvent is executed, then vkResetEvent has no effect, and no event unsignal operation occurs.

Valid Usage

- `event` must not be waited on by a `vkCmdWaitEvents` command that is currently executing

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `event` must be a valid VkEvent handle

- `event` must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `event` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The state of an event can also be updated on the device by commands inserted in command buffers.

To set the state of an event to signaled from a device, call:

    void vkCmdSetEvent(
        VkCommandBuffer                             commandBuffer,
        VkEvent                                     event,
        VkPipelineStageFlags                        stageMask);

- `commandBuffer` is the command buffer into which the command is recorded.

- `event` is the event that will be signaled.

- `stageMask` specifies the source stage mask used to determine when the `event` is signaled.

When vkCmdSetEvent is submitted to a queue, it defines an execution dependency on commands that were submitted before it, and defines an event signal operation which sets the event to the signaled state.

The first synchronization scope includes all commands that occur earlier in submission order. The synchronization scope is limited to operations on the pipeline stages determined by the source stage mask specified by `stageMask`.

The second synchronization scope includes only the event signal operation.

If `event` is already in the signaled state when vkCmdSetEvent is executed on the device, then vkCmdSetEvent has no effect, no event signal operation occurs, and no execution dependency is generated.

Valid Usage

- `stageMask` must not include `VK_PIPELINE_STAGE_HOST_BIT`

- If the geometry shaders feature is not enabled, `stageMask` must not contain `VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT`

- If the tessellation shaders feature is not enabled, `stageMask` must not contain `VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT` or `VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT`

- `commandBuffer`’s current device mask must include exactly one physical device.

- If the mesh shaders feature is not enabled, `stageMask` must not contain `VK_PIPELINE_STAGE_MESH_SHADER_BIT_NV`

- If the task shaders feature is not enabled, `stageMask` must not contain `VK_PIPELINE_STAGE_TASK_SHADER_BIT_NV`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `event` must be a valid VkEvent handle

- `stageMask` must be a valid combination of VkPipelineStageFlagBits values

- `stageMask` must not be `0`

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

- This command must only be called outside of a render pass instance

- Both of `commandBuffer`, and `event` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Graphics Compute |

To set the state of an event to unsignaled from a device, call:

    void vkCmdResetEvent(
        VkCommandBuffer                             commandBuffer,
        VkEvent                                     event,
        VkPipelineStageFlags                        stageMask);

- `commandBuffer` is the command buffer into which the command is recorded.

- `event` is the event that will be unsignaled.

- `stageMask` is a bitmask of VkPipelineStageFlagBits specifying the source stage mask used to determine when the `event` is unsignaled.

When vkCmdResetEvent is submitted to a queue, it defines an execution dependency on commands that were submitted before it, and defines an event unsignal operation which resets the event to the unsignaled state.

The first synchronization scope includes all commands that occur earlier in submission order. The synchronization scope is limited to operations on the pipeline stages determined by the source stage mask specified by `stageMask`.

The second synchronization scope includes only the event unsignal operation.

If `event` is already in the unsignaled state when vkCmdResetEvent is executed on the device, then vkCmdResetEvent has no effect, no event unsignal operation occurs, and no execution dependency is generated.

Valid Usage

- `stageMask` must not include `VK_PIPELINE_STAGE_HOST_BIT`

- If the geometry shaders feature is not enabled, `stageMask` must not contain `VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT`

- If the tessellation shaders feature is not enabled, `stageMask` must not contain `VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT` or `VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT`

- When this command executes, `event` must not be waited on by a `vkCmdWaitEvents` command that is currently executing

- `commandBuffer`’s current device mask must include exactly one physical device.

- If the mesh shaders feature is not enabled, `stageMask` must not contain `VK_PIPELINE_STAGE_MESH_SHADER_BIT_NV`

- If the task shaders feature is not enabled, `stageMask` must not contain `VK_PIPELINE_STAGE_TASK_SHADER_BIT_NV`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `event` must be a valid VkEvent handle

- `stageMask` must be a valid combination of VkPipelineStageFlagBits values

- `stageMask` must not be `0`

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

- This command must only be called outside of a render pass instance

- Both of `commandBuffer`, and `event` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Graphics Compute |

To wait for one or more events to enter the signaled state on a device, call:

    void vkCmdWaitEvents(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    eventCount,
        const VkEvent*                              pEvents,
        VkPipelineStageFlags                        srcStageMask,
        VkPipelineStageFlags                        dstStageMask,
        uint32_t                                    memoryBarrierCount,
        const VkMemoryBarrier*                      pMemoryBarriers,
        uint32_t                                    bufferMemoryBarrierCount,
        const VkBufferMemoryBarrier*                pBufferMemoryBarriers,
        uint32_t                                    imageMemoryBarrierCount,
        const VkImageMemoryBarrier*                 pImageMemoryBarriers);

- `commandBuffer` is the command buffer into which the command is recorded.

- `eventCount` is the length of the `pEvents` array.

- `pEvents` is a pointer to an array of event object handles to wait on.

- `srcStageMask` is a bitmask of VkPipelineStageFlagBits specifying the source stage mask.

- `dstStageMask` is a bitmask of VkPipelineStageFlagBits specifying the destination stage mask.

- `memoryBarrierCount` is the length of the `pMemoryBarriers` array.

- `pMemoryBarriers` is a pointer to an array of VkMemoryBarrier structures.

- `bufferMemoryBarrierCount` is the length of the `pBufferMemoryBarriers` array.

- `pBufferMemoryBarriers` is a pointer to an array of VkBufferMemoryBarrier structures.

- `imageMemoryBarrierCount` is the length of the `pImageMemoryBarriers` array.

- `pImageMemoryBarriers` is a pointer to an array of VkImageMemoryBarrier structures.

When `vkCmdWaitEvents` is submitted to a queue, it defines a memory dependency between prior event signal operations on the same queue or the host, and subsequent commands. `vkCmdWaitEvents` must not be used to wait on event signal operations occurring on other queues.

The first synchronization scope only includes event signal operations that operate on members of `pEvents`, and the operations that happened-before the event signal operations. Event signal operations performed by vkCmdSetEvent that occur earlier in submission order are included in the first synchronization scope, if the logically latest pipeline stage in their `stageMask` parameter is logically earlier than or equal to the logically latest pipeline stage in `srcStageMask`. Event signal operations performed by vkSetEvent are only included in the first synchronization scope if `VK_PIPELINE_STAGE_HOST_BIT` is included in `srcStageMask`.

The second synchronization scope includes all commands that occur later in submission order. The second synchronization scope is limited to operations on the pipeline stages determined by the destination stage mask specified by `dstStageMask`.

The first access scope is limited to access in the pipeline stages determined by the source stage mask specified by `srcStageMask`. Within that, the first access scope only includes the first access scopes defined by elements of the `pMemoryBarriers`, `pBufferMemoryBarriers` and `pImageMemoryBarriers` arrays, which each define a set of memory barriers. If no memory barriers are specified, then the first access scope includes no accesses.

The second access scope is limited to access in the pipeline stages determined by the destination stage mask specified by `dstStageMask`. Within that, the second access scope only includes the second access scopes defined by elements of the `pMemoryBarriers`, `pBufferMemoryBarriers` and `pImageMemoryBarriers` arrays, which each define a set of memory barriers. If no memory barriers are specified, then the second access scope includes no accesses.

| Note vkCmdWaitEvents is used with vkCmdSetEvent to define a memory dependency between two sets of action commands, roughly in the same way as pipeline barriers, but split into two commands such that work between the two may execute unhindered. Unlike vkCmdPipelineBarrier, a queue family ownership transfer cannot be performed using vkCmdWaitEvents.

| Note Applications should be careful to avoid race conditions when using events. There is no direct ordering guarantee between a vkCmdResetEvent command and a vkCmdWaitEvents command submitted after it, so some other execution dependency must be included between these commands (e.g. a semaphore).

Valid Usage

- `srcStageMask` must be the bitwise OR of the `stageMask` parameter used in previous calls to `vkCmdSetEvent` with any of the members of `pEvents` and `VK_PIPELINE_STAGE_HOST_BIT` if any of the members of `pEvents` was set using `vkSetEvent`

- If the geometry shaders feature is not enabled, `srcStageMask` must not contain `VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT`

- If the geometry shaders feature is not enabled, `dstStageMask` must not contain `VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT`

- If the tessellation shaders feature is not enabled, `srcStageMask` must not contain `VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT` or `VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT`

- If the tessellation shaders feature is not enabled, `dstStageMask` must not contain `VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT` or `VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT`

- If `pEvents` includes one or more events that will be signaled by `vkSetEvent` after `commandBuffer` has been submitted to a queue, then `vkCmdWaitEvents` must not be called inside a render pass instance

- Any pipeline stage included in `srcStageMask` or `dstStageMask` must be supported by the capabilities of the queue family specified by the `queueFamilyIndex` member of the VkCommandPoolCreateInfo structure that was used to create the `VkCommandPool` that `commandBuffer` was allocated from, as specified in the table of supported pipeline stages.

- Each element of `pMemoryBarriers`, `pBufferMemoryBarriers` or `pImageMemoryBarriers` must not have any access flag included in its `srcAccessMask` member if that bit is not supported by any of the pipeline stages in `srcStageMask`, as specified in the table of supported access types.

- Each element of `pMemoryBarriers`, `pBufferMemoryBarriers` or `pImageMemoryBarriers` must not have any access flag included in its `dstAccessMask` member if that bit is not supported by any of the pipeline stages in `dstStageMask`, as specified in the table of supported access types.

- The `srcQueueFamilyIndex` and `dstQueueFamilyIndex` members of any element of `pBufferMemoryBarriers` or `pImageMemoryBarriers` must be equal.

- `commandBuffer`’s current device mask must include exactly one physical device.

- If the mesh shaders feature is not enabled, `srcStageMask` must not contain `VK_PIPELINE_STAGE_MESH_SHADER_BIT_NV`

- If the task shaders feature is not enabled, `srcStageMask` must not contain `VK_PIPELINE_STAGE_TASK_SHADER_BIT_NV`

- If the mesh shaders feature is not enabled, `dstStageMask` must not contain `VK_PIPELINE_STAGE_MESH_SHADER_BIT_NV`

- If the task shaders feature is not enabled, `dstStageMask` must not contain `VK_PIPELINE_STAGE_TASK_SHADER_BIT_NV`

- The `srcAccessMask` member of each element of `pMemoryBarriers` must only include access flags that are supported by one or more of the pipeline stages in `srcStageMask`, as specified in the table of supported access types

- The `dstAccessMask` member of each element of `pMemoryBarriers` must only include access flags that are supported by one or more of the pipeline stages in `dstStageMask`, as specified in the table of supported access types

- The `srcAccessMask` member of each element of `pBufferMemoryBarriers` must only include access flags that are supported by one or more of the pipeline stages in `srcStageMask`, as specified in the table of supported access types

- The `dstAccessMask` member of each element of `pBufferMemoryBarriers` must only include access flags that are supported by one or more of the pipeline stages in `dstStageMask`, as specified in the table of supported access types

- The `srcAccessMask` member of each element of `pImageMemoryBarriers` must only include access flags that are supported by one or more of the pipeline stages in `srcStageMask`, as specified in the table of supported access types

- The `dstAccessMask` member of any element of `pImageMemoryBarriers` must only include access flags that are supported by one or more of the pipeline stages in `dstStageMask`, as specified in the table of supported access types

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pEvents` must be a valid pointer to an array of `eventCount` valid VkEvent handles

- `srcStageMask` must be a valid combination of VkPipelineStageFlagBits values

- `srcStageMask` must not be `0`

- `dstStageMask` must be a valid combination of VkPipelineStageFlagBits values

- `dstStageMask` must not be `0`

- If `memoryBarrierCount` is not `0`, `pMemoryBarriers` must be a valid pointer to an array of `memoryBarrierCount` valid VkMemoryBarrier structures

- If `bufferMemoryBarrierCount` is not `0`, `pBufferMemoryBarriers` must be a valid pointer to an array of `bufferMemoryBarrierCount` valid VkBufferMemoryBarrier structures

- If `imageMemoryBarrierCount` is not `0`, `pImageMemoryBarriers` must be a valid pointer to an array of `imageMemoryBarrierCount` valid VkImageMemoryBarrier structures

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

- `eventCount` must be greater than `0`

- Both of `commandBuffer`, and the elements of `pEvents` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute |

### 6.6. Pipeline Barriers

vkCmdPipelineBarrier is a synchronization command that inserts a dependency between commands submitted to the same queue, or between commands in the same subpass.

To record a pipeline barrier, call:

    void vkCmdPipelineBarrier(
        VkCommandBuffer                             commandBuffer,
        VkPipelineStageFlags                        srcStageMask,
        VkPipelineStageFlags                        dstStageMask,
        VkDependencyFlags                           dependencyFlags,
        uint32_t                                    memoryBarrierCount,
        const VkMemoryBarrier*                      pMemoryBarriers,
        uint32_t                                    bufferMemoryBarrierCount,
        const VkBufferMemoryBarrier*                pBufferMemoryBarriers,
        uint32_t                                    imageMemoryBarrierCount,
        const VkImageMemoryBarrier*                 pImageMemoryBarriers);

- `commandBuffer` is the command buffer into which the command is recorded.

- `srcStageMask` is a bitmask of VkPipelineStageFlagBits specifying the source stage mask.

- `dstStageMask` is a bitmask of VkPipelineStageFlagBits specifying the destination stage mask.

- `dependencyFlags` is a bitmask of VkDependencyFlagBits specifying how execution and memory dependencies are formed.

- `memoryBarrierCount` is the length of the `pMemoryBarriers` array.

- `pMemoryBarriers` is a pointer to an array of VkMemoryBarrier structures.

- `bufferMemoryBarrierCount` is the length of the `pBufferMemoryBarriers` array.

- `pBufferMemoryBarriers` is a pointer to an array of VkBufferMemoryBarrier structures.

- `imageMemoryBarrierCount` is the length of the `pImageMemoryBarriers` array.

- `pImageMemoryBarriers` is a pointer to an array of VkImageMemoryBarrier structures.

When vkCmdPipelineBarrier is submitted to a queue, it defines a memory dependency between commands that were submitted before it, and those submitted after it.

If vkCmdPipelineBarrier was recorded outside a render pass instance, the first synchronization scope includes all commands that occur earlier in submission order. If vkCmdPipelineBarrier was recorded inside a render pass instance, the first synchronization scope includes only commands that occur earlier in submission order within the same subpass. In either case, the first synchronization scope is limited to operations on the pipeline stages determined by the source stage mask specified by `srcStageMask`.

If vkCmdPipelineBarrier was recorded outside a render pass instance, the second synchronization scope includes all commands that occur later in submission order. If vkCmdPipelineBarrier was recorded inside a render pass instance, the second synchronization scope includes only commands that occur later in submission order within the same subpass. In either case, the second synchronization scope is limited to operations on the pipeline stages determined by the destination stage mask specified by `dstStageMask`.

The first access scope is limited to access in the pipeline stages determined by the source stage mask specified by `srcStageMask`. Within that, the first access scope only includes the first access scopes defined by elements of the `pMemoryBarriers`, `pBufferMemoryBarriers` and `pImageMemoryBarriers` arrays, which each define a set of memory barriers. If no memory barriers are specified, then the first access scope includes no accesses.

The second access scope is limited to access in the pipeline stages determined by the destination stage mask specified by `dstStageMask`. Within that, the second access scope only includes the second access scopes defined by elements of the `pMemoryBarriers`, `pBufferMemoryBarriers` and `pImageMemoryBarriers` arrays, which each define a set of memory barriers. If no memory barriers are specified, then the second access scope includes no accesses.

If `dependencyFlags` includes `VK_DEPENDENCY_BY_REGION_BIT`, then any dependency between framebuffer-space pipeline stages is framebuffer-local - otherwise it is framebuffer-global.

Valid Usage

- If the geometry shaders feature is not enabled, `srcStageMask` must not contain `VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT`

- If the geometry shaders feature is not enabled, `dstStageMask` must not contain `VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT`

- If the tessellation shaders feature is not enabled, `srcStageMask` must not contain `VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT` or `VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT`

- If the tessellation shaders feature is not enabled, `dstStageMask` must not contain `VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT` or `VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT`

- If `vkCmdPipelineBarrier` is called within a render pass instance, the render pass must have been created with at least one `VkSubpassDependency` instance in `VkRenderPassCreateInfo`::`pDependencies` that expresses a dependency from the current subpass to itself, and for which `srcStageMask` contains a subset of the bit values in `VkSubpassDependency`::`srcStageMask`, `dstStageMask` contains a subset of the bit values in `VkSubpassDependency`::`dstStageMask`, `dependencyFlags` is equal to `VkSubpassDependency`::`dependencyFlags`, `srcAccessMask` member of each element of `pMemoryBarriers` and `pImageMemoryBarriers` contains a subset of the bit values in `VkSubpassDependency`::`srcAccessMask`, and `dstAccessMask` member of each element of `pMemoryBarriers` and `pImageMemoryBarriers` contains a subset of the bit values in `VkSubpassDependency`::`dstAccessMask`

- If `vkCmdPipelineBarrier` is called within a render pass instance, `bufferMemoryBarrierCount` must be `0`

- If `vkCmdPipelineBarrier` is called within a render pass instance, the `image` member of any element of `pImageMemoryBarriers` must be equal to one of the elements of `pAttachments` that the current `framebuffer` was created with, that is also referred to by one of the elements of the `pColorAttachments`, `pResolveAttachments` or `pDepthStencilAttachment` members of the `VkSubpassDescription` instance or by the `pDepthStencilResolveAttachment` member of the `VkSubpassDescriptionDepthStencilResolve` structure that the current subpass was created with

- If `vkCmdPipelineBarrier` is called within a render pass instance, the `oldLayout` and `newLayout` members of any element of `pImageMemoryBarriers` must be equal to the `layout` member of an element of the `pColorAttachments`, `pResolveAttachments` or `pDepthStencilAttachment` members of the `VkSubpassDescription` instance or by the `pDepthStencilResolveAttachment` member of the `VkSubpassDescriptionDepthStencilResolve` structure that the current subpass was created with, that refers to the same `image`

- If `vkCmdPipelineBarrier` is called within a render pass instance, the `oldLayout` and `newLayout` members of an element of `pImageMemoryBarriers` must be equal

- If `vkCmdPipelineBarrier` is called within a render pass instance, the `srcQueueFamilyIndex` and `dstQueueFamilyIndex` members of any element of `pImageMemoryBarriers` must be `VK_QUEUE_FAMILY_IGNORED`

- Any pipeline stage included in `srcStageMask` or `dstStageMask` must be supported by the capabilities of the queue family specified by the `queueFamilyIndex` member of the VkCommandPoolCreateInfo structure that was used to create the `VkCommandPool` that `commandBuffer` was allocated from, as specified in the table of supported pipeline stages

- If `vkCmdPipelineBarrier` is called outside of a render pass instance, `dependencyFlags` must not include `VK_DEPENDENCY_VIEW_LOCAL_BIT`

- If the mesh shaders feature is not enabled, `srcStageMask` must not contain `VK_PIPELINE_STAGE_MESH_SHADER_BIT_NV`

- If the task shaders feature is not enabled, `srcStageMask` must not contain `VK_PIPELINE_STAGE_TASK_SHADER_BIT_NV`

- If the mesh shaders feature is not enabled, `dstStageMask` must not contain `VK_PIPELINE_STAGE_MESH_SHADER_BIT_NV`

- If the task shaders feature is not enabled, `dstStageMask` must not contain `VK_PIPELINE_STAGE_TASK_SHADER_BIT_NV`

- The `srcAccessMask` member of each element of `pMemoryBarriers` must only include access flags that are supported by one or more of the pipeline stages in `srcStageMask`, as specified in the table of supported access types

- The `dstAccessMask` member of each element of `pMemoryBarriers` must only include access flags that are supported by one or more of the pipeline stages in `dstStageMask`, as specified in the table of supported access types

- For any element of `pBufferMemoryBarriers`, if its `srcQueueFamilyIndex` and `dstQueueFamilyIndex` members are equal, or if its `srcQueueFamilyIndex` is the queue family index that was used to create the command pool that `commandBuffer` was allocated from, then its `srcAccessMask` member must only contain access flags that are supported by one or more of the pipeline stages in `srcStageMask`, as specified in the table of supported access types

- For any element of `pBufferMemoryBarriers`, if its `srcQueueFamilyIndex` and `dstQueueFamilyIndex` members are equal, or if its `dstQueueFamilyIndex` is the queue family index that was used to create the command pool that `commandBuffer` was allocated from, then its `dstAccessMask` member must only contain access flags that are supported by one or more of the pipeline stages in `dstStageMask`, as specified in the table of supported access types

- For any element of `pImageMemoryBarriers`, if its `srcQueueFamilyIndex` and `dstQueueFamilyIndex` members are equal, or if its `srcQueueFamilyIndex` is the queue family index that was used to create the command pool that `commandBuffer` was allocated from, then its `srcAccessMask` member must only contain access flags that are supported by one or more of the pipeline stages in `srcStageMask`, as specified in the table of supported access types

- For any element of `pImageMemoryBarriers`, if its `srcQueueFamilyIndex` and `dstQueueFamilyIndex` members are equal, or if its `dstQueueFamilyIndex` is the queue family index that was used to create the command pool that `commandBuffer` was allocated from, then its `dstAccessMask` member must only contain access flags that are supported by one or more of the pipeline stages in `dstStageMask`, as specified in the table of supported access types

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `srcStageMask` must be a valid combination of VkPipelineStageFlagBits values

- `srcStageMask` must not be `0`

- `dstStageMask` must be a valid combination of VkPipelineStageFlagBits values

- `dstStageMask` must not be `0`

- `dependencyFlags` must be a valid combination of VkDependencyFlagBits values

- If `memoryBarrierCount` is not `0`, `pMemoryBarriers` must be a valid pointer to an array of `memoryBarrierCount` valid VkMemoryBarrier structures

- If `bufferMemoryBarrierCount` is not `0`, `pBufferMemoryBarriers` must be a valid pointer to an array of `bufferMemoryBarrierCount` valid VkBufferMemoryBarrier structures

- If `imageMemoryBarrierCount` is not `0`, `pImageMemoryBarriers` must be a valid pointer to an array of `imageMemoryBarrierCount` valid VkImageMemoryBarrier structures

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support transfer, graphics, or compute operations

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Transfer Graphics Compute |

Bits which can be set in `vkCmdPipelineBarrier`::`dependencyFlags`, specifying how execution and memory dependencies are formed, are:

    typedef enum VkDependencyFlagBits {
        VK_DEPENDENCY_BY_REGION_BIT = 0x00000001,
        VK_DEPENDENCY_DEVICE_GROUP_BIT = 0x00000004,
        VK_DEPENDENCY_VIEW_LOCAL_BIT = 0x00000002,
        VK_DEPENDENCY_VIEW_LOCAL_BIT_KHR = VK_DEPENDENCY_VIEW_LOCAL_BIT,
        VK_DEPENDENCY_DEVICE_GROUP_BIT_KHR = VK_DEPENDENCY_DEVICE_GROUP_BIT,
        VK_DEPENDENCY_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkDependencyFlagBits;

- `VK_DEPENDENCY_BY_REGION_BIT` specifies that dependencies will be framebuffer-local.

- `VK_DEPENDENCY_VIEW_LOCAL_BIT` specifies that a subpass has more than one view.

- `VK_DEPENDENCY_DEVICE_GROUP_BIT` specifies that dependencies are non-device-local dependency.

    typedef VkFlags VkDependencyFlags;

`VkDependencyFlags` is a bitmask type for setting a mask of zero or more VkDependencyFlagBits.

#### 6.6.1. Subpass Self-dependency

If `vkCmdPipelineBarrier` is called inside a render pass instance, the following restrictions apply. For a given subpass to allow a pipeline barrier, the render pass must declare a self-dependency from that subpass to itself. That is, there must exist a `VkSubpassDependency` in the subpass dependency list for the render pass with `srcSubpass` and `dstSubpass` equal to that subpass index. More than one self-dependency can be declared for each subpass.

Self-dependencies must only include pipeline stage bits that are graphics stages. If any of the stages in `srcStages` are framebuffer-space stages, `dstStages` must only contain framebuffer-space stages. Additionally, `srcStages` must not contain `VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT` in a self-dependency.

If the source and destination stage masks both include framebuffer-space stages, then `dependencyFlags` must include `VK_DEPENDENCY_BY_REGION_BIT`. If the subpass has more than one view, then `dependencyFlags` must include `VK_DEPENDENCY_VIEW_LOCAL_BIT`.

A `vkCmdPipelineBarrier` command inside a render pass instance must be a subset of one of the self-dependencies of the subpass it is used in, meaning that the stage masks and access masks must each include only a subset of the bits of the corresponding mask in that self-dependency. If the self-dependency has `VK_DEPENDENCY_BY_REGION_BIT` or `VK_DEPENDENCY_VIEW_LOCAL_BIT` set, then so must the pipeline barrier. Pipeline barriers within a render pass instance can only be types `VkMemoryBarrier` or `VkImageMemoryBarrier`. If a `VkImageMemoryBarrier` is used, the image and image subresource range specified in the barrier must be a subset of one of the image views used by the framebuffer in the current subpass. Additionally, `oldLayout` must be equal to `newLayout`, and both the `srcQueueFamilyIndex` and `dstQueueFamilyIndex` must be `VK_QUEUE_FAMILY_IGNORED`.

### 6.7. Memory Barriers

Memory barriers are used to explicitly control access to buffer and image subresource ranges. Memory barriers are used to transfer ownership between queue families, change image layouts, and define availability and visibility operations. They explicitly define the access types and buffer and image subresource ranges that are included in the access scopes of a memory dependency that is created by a synchronization command that includes them.

#### 6.7.1. Global Memory Barriers

Global memory barriers apply to memory accesses involving all memory objects that exist at the time of its execution.

The `VkMemoryBarrier` structure is defined as:

    typedef struct VkMemoryBarrier {
        VkStructureType    sType;
        const void*        pNext;
        VkAccessFlags      srcAccessMask;
        VkAccessFlags      dstAccessMask;
    } VkMemoryBarrier;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `srcAccessMask` is a bitmask of VkAccessFlagBits specifying a source access mask.

- `dstAccessMask` is a bitmask of VkAccessFlagBits specifying a destination access mask.

The first access scope is limited to access types in the source access mask specified by `srcAccessMask`.

The second access scope is limited to access types in the destination access mask specified by `dstAccessMask`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_MEMORY_BARRIER`

- `pNext` must be `NULL`

- `srcAccessMask` must be a valid combination of VkAccessFlagBits values

- `dstAccessMask` must be a valid combination of VkAccessFlagBits values

#### 6.7.2. Buffer Memory Barriers

Buffer memory barriers only apply to memory accesses involving a specific buffer range. That is, a memory dependency formed from a buffer memory barrier is scoped to access via the specified buffer range. Buffer memory barriers can also be used to define a queue family ownership transfer for the specified buffer range.

The `VkBufferMemoryBarrier` structure is defined as:

    typedef struct VkBufferMemoryBarrier {
        VkStructureType    sType;
        const void*        pNext;
        VkAccessFlags      srcAccessMask;
        VkAccessFlags      dstAccessMask;
        uint32_t           srcQueueFamilyIndex;
        uint32_t           dstQueueFamilyIndex;
        VkBuffer           buffer;
        VkDeviceSize       offset;
        VkDeviceSize       size;
    } VkBufferMemoryBarrier;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `srcAccessMask` is a bitmask of VkAccessFlagBits specifying a source access mask.

- `dstAccessMask` is a bitmask of VkAccessFlagBits specifying a destination access mask.

- `srcQueueFamilyIndex` is the source queue family for a queue family ownership transfer.

- `dstQueueFamilyIndex` is the destination queue family for a queue family ownership transfer.

- `buffer` is a handle to the buffer whose backing memory is affected by the barrier.

- `offset` is an offset in bytes into the backing memory for `buffer`; this is relative to the base offset as bound to the buffer (see vkBindBufferMemory).

- `size` is a size in bytes of the affected area of backing memory for `buffer`, or `VK_WHOLE_SIZE` to use the range from `offset` to the end of the buffer.

The first access scope is limited to access to memory through the specified buffer range, via access types in the source access mask specified by `srcAccessMask`. If `srcAccessMask` includes `VK_ACCESS_HOST_WRITE_BIT`, memory writes performed by that access type are also made visible, as that access type is not performed through a resource.

The second access scope is limited to access to memory through the specified buffer range, via access types in the destination access mask. specified by `dstAccessMask`. If `dstAccessMask` includes `VK_ACCESS_HOST_WRITE_BIT` or `VK_ACCESS_HOST_READ_BIT`, available memory writes are also made visible to accesses of those types, as those access types are not performed through a resource.

If `srcQueueFamilyIndex` is not equal to `dstQueueFamilyIndex`, and `srcQueueFamilyIndex` is equal to the current queue family, then the memory barrier defines a queue family release operation for the specified buffer range, and the second access scope includes no access, as if `dstAccessMask` was `0`.

If `dstQueueFamilyIndex` is not equal to `srcQueueFamilyIndex`, and `dstQueueFamilyIndex` is equal to the current queue family, then the memory barrier defines a queue family acquire operation for the specified buffer range, and the first access scope includes no access, as if `srcAccessMask` was `0`.

Valid Usage

- `offset` must be less than the size of `buffer`

- If `size` is not equal to `VK_WHOLE_SIZE`, `size` must be greater than `0`

- If `size` is not equal to `VK_WHOLE_SIZE`, `size` must be less than or equal to than the size of `buffer` minus `offset`

- If `buffer` was created with a sharing mode of `VK_SHARING_MODE_CONCURRENT`, at least one of `srcQueueFamilyIndex` and `dstQueueFamilyIndex` must be `VK_QUEUE_FAMILY_IGNORED`

- If `buffer` was created with a sharing mode of `VK_SHARING_MODE_CONCURRENT`, and one of `srcQueueFamilyIndex` and `dstQueueFamilyIndex` is `VK_QUEUE_FAMILY_IGNORED`, the other must be `VK_QUEUE_FAMILY_IGNORED` or a special queue family reserved for external memory ownership transfers, as described in Queue Family Ownership Transfer.

- If `buffer` was created with a sharing mode of `VK_SHARING_MODE_EXCLUSIVE` and `srcQueueFamilyIndex` is `VK_QUEUE_FAMILY_IGNORED`, `dstQueueFamilyIndex` must also be `VK_QUEUE_FAMILY_IGNORED`

- If `buffer` was created with a sharing mode of `VK_SHARING_MODE_EXCLUSIVE` and `srcQueueFamilyIndex` is not `VK_QUEUE_FAMILY_IGNORED`, it must be a valid queue family or a special queue family reserved for external memory transfers, as described in Queue Family Ownership Transfer.

- If `buffer` was created with a sharing mode of `VK_SHARING_MODE_EXCLUSIVE` and `dstQueueFamilyIndex` is not `VK_QUEUE_FAMILY_IGNORED`, it must be a valid queue family or a special queue family reserved for external memory transfers, as described in Queue Family Ownership Transfer.

- If `buffer` was created with a sharing mode of `VK_SHARING_MODE_EXCLUSIVE`, and `srcQueueFamilyIndex` and `dstQueueFamilyIndex` are not `VK_QUEUE_FAMILY_IGNORED`, at least one of them must be the same as the family of the queue that will execute this barrier

- If `buffer` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_BUFFER_MEMORY_BARRIER`

- `pNext` must be `NULL`

- `buffer` must be a valid VkBuffer handle

#### 6.7.3. Image Memory Barriers

Image memory barriers only apply to memory accesses involving a specific image subresource range. That is, a memory dependency formed from an image memory barrier is scoped to access via the specified image subresource range. Image memory barriers can also be used to define image layout transitions or a queue family ownership transfer for the specified image subresource range.

The `VkImageMemoryBarrier` structure is defined as:

    typedef struct VkImageMemoryBarrier {
        VkStructureType            sType;
        const void*                pNext;
        VkAccessFlags              srcAccessMask;
        VkAccessFlags              dstAccessMask;
        VkImageLayout              oldLayout;
        VkImageLayout              newLayout;
        uint32_t                   srcQueueFamilyIndex;
        uint32_t                   dstQueueFamilyIndex;
        VkImage                    image;
        VkImageSubresourceRange    subresourceRange;
    } VkImageMemoryBarrier;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `srcAccessMask` is a bitmask of VkAccessFlagBits specifying a source access mask.

- `dstAccessMask` is a bitmask of VkAccessFlagBits specifying a destination access mask.

- `oldLayout` is the old layout in an image layout transition.

- `newLayout` is the new layout in an image layout transition.

- `srcQueueFamilyIndex` is the source queue family for a queue family ownership transfer.

- `dstQueueFamilyIndex` is the destination queue family for a queue family ownership transfer.

- `image` is a handle to the image affected by this barrier.

- `subresourceRange` describes the image subresource range within `image` that is affected by this barrier.

The first access scope is limited to access to memory through the specified image subresource range, via access types in the source access mask specified by `srcAccessMask`. If `srcAccessMask` includes `VK_ACCESS_HOST_WRITE_BIT`, memory writes performed by that access type are also made visible, as that access type is not performed through a resource.

The second access scope is limited to access to memory through the specified image subresource range, via access types in the destination access mask specified by `dstAccessMask`. If `dstAccessMask` includes `VK_ACCESS_HOST_WRITE_BIT` or `VK_ACCESS_HOST_READ_BIT`, available memory writes are also made visible to accesses of those types, as those access types are not performed through a resource.

If `srcQueueFamilyIndex` is not equal to `dstQueueFamilyIndex`, and `srcQueueFamilyIndex` is equal to the current queue family, then the memory barrier defines a queue family release operation for the specified image subresource range, and the second access scope includes no access, as if `dstAccessMask` was `0`.

If `dstQueueFamilyIndex` is not equal to `srcQueueFamilyIndex`, and `dstQueueFamilyIndex` is equal to the current queue family, then the memory barrier defines a queue family acquire operation for the specified image subresource range, and the first access scope includes no access, as if `srcAccessMask` was `0`.

If `oldLayout` is not equal to `newLayout`, then the memory barrier defines an image layout transition for the specified image subresource range.

Layout transitions that are performed via image memory barriers execute in their entirety in submission order, relative to other image layout transitions submitted to the same queue, including those performed by render passes. In effect there is an implicit execution dependency from each such layout transition to all layout transitions previously submitted to the same queue.

The image layout of each image subresource of a depth/stencil image created with `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT` is dependent on the last sample locations used to render to the image subresource as a depth/stencil attachment, thus when the `image` member of a `VkImageMemoryBarrier` is an image created with this flag the application can include a VkSampleLocationsInfoEXT structure in the `pNext` chain of `VkImageMemoryBarrier` to specify the sample locations to use during the image layout transition.

If the `VkSampleLocationsInfoEXT` structure included in the `pNext` chain of `VkImageMemoryBarrier` does not match the sample location state last used to render to the image subresource range specified by `subresourceRange` or if no `VkSampleLocationsInfoEXT` structure is included in the `pNext` chain of `VkImageMemoryBarrier`, then the contents of the given image subresource range becomes undefined as if `oldLayout` would equal `VK_IMAGE_LAYOUT_UNDEFINED`.

If `image` has a multi-planar format and the image is disjoint, then including `VK_IMAGE_ASPECT_COLOR_BIT` in the `aspectMask` member of `subresourceRange` is equivalent to including `VK_IMAGE_ASPECT_PLANE_0_BIT`, `VK_IMAGE_ASPECT_PLANE_1_BIT`, and (for three-plane formats only) `VK_IMAGE_ASPECT_PLANE_2_BIT`.

Valid Usage

- `oldLayout` must be `VK_IMAGE_LAYOUT_UNDEFINED` or the current layout of the image subresources affected by the barrier

- `newLayout` must not be `VK_IMAGE_LAYOUT_UNDEFINED` or `VK_IMAGE_LAYOUT_PREINITIALIZED`

- If `image` was created with a sharing mode of `VK_SHARING_MODE_CONCURRENT`, at least one of `srcQueueFamilyIndex` and `dstQueueFamilyIndex` must be `VK_QUEUE_FAMILY_IGNORED`

- If `image` was created with a sharing mode of `VK_SHARING_MODE_CONCURRENT`, and one of `srcQueueFamilyIndex` and `dstQueueFamilyIndex` is `VK_QUEUE_FAMILY_IGNORED`, the other must be `VK_QUEUE_FAMILY_IGNORED` or a special queue family reserved for external memory transfers, as described in Queue Family Ownership Transfer.

- If `image` was created with a sharing mode of `VK_SHARING_MODE_EXCLUSIVE` and `srcQueueFamilyIndex` is `VK_QUEUE_FAMILY_IGNORED`, `dstQueueFamilyIndex` must also be `VK_QUEUE_FAMILY_IGNORED`.

- If `image` was created with a sharing mode of `VK_SHARING_MODE_EXCLUSIVE` and `srcQueueFamilyIndex` is not `VK_QUEUE_FAMILY_IGNORED`, it must be a valid queue family or a special queue family reserved for external memory transfers, as described in Queue Family Ownership Transfer.

- If `image` was created with a sharing mode of `VK_SHARING_MODE_EXCLUSIVE` and `dstQueueFamilyIndex` is not `VK_QUEUE_FAMILY_IGNORED`, it must be a valid queue family or a special queue family reserved for external memory transfers, as described in Queue Family Ownership Transfer.

- If `image` was created with a sharing mode of `VK_SHARING_MODE_EXCLUSIVE`, and `srcQueueFamilyIndex` and `dstQueueFamilyIndex` are not `VK_QUEUE_FAMILY_IGNORED`, at least one of them must be the same as the family of the queue that will execute this barrier

- `subresourceRange.baseMipLevel` must be less than the `mipLevels` specified in VkImageCreateInfo when `image` was created

- If `subresourceRange.levelCount` is not `VK_REMAINING_MIP_LEVELS`, `subresourceRange.baseMipLevel` + `subresourceRange.levelCount` must be less than or equal to the `mipLevels` specified in VkImageCreateInfo when `image` was created

- `subresourceRange.baseArrayLayer` must be less than the `arrayLayers` specified in VkImageCreateInfo when `image` was created

- If `subresourceRange.layerCount` is not `VK_REMAINING_ARRAY_LAYERS`, `subresourceRange.baseArrayLayer` + `subresourceRange.layerCount` must be less than or equal to the `arrayLayers` specified in VkImageCreateInfo when `image` was created

- If `image` has a depth/stencil format with both depth and stencil and the separateDepthStencilLayouts feature is enabled, then the `aspectMask` member of `subresourceRange` must include either or both `VK_IMAGE_ASPECT_DEPTH_BIT` and `VK_IMAGE_ASPECT_STENCIL_BIT`

- If `image` has a depth/stencil format with both depth and stencil and the separateDepthStencilLayouts feature is not enabled, then the `aspectMask` member of `subresourceRange` must include both `VK_IMAGE_ASPECT_DEPTH_BIT` and `VK_IMAGE_ASPECT_STENCIL_BIT`

- If `image` has a color format and either the format is single-plane or the image is not disjoint then the `aspectMask` member of `subresourceRange` must only include `VK_IMAGE_ASPECT_COLOR_BIT`

- If `image` has a multi-planar format and the image is disjoint, then the `aspectMask` member of `subresourceRange` must include either at least one of `VK_IMAGE_ASPECT_PLANE_0_BIT`, `VK_IMAGE_ASPECT_PLANE_1_BIT`, and `VK_IMAGE_ASPECT_PLANE_2_BIT`; or must include `VK_IMAGE_ASPECT_COLOR_BIT`

- If `image` has a multi-planar format with only two planes, then the `aspectMask` member of `subresourceRange` must not include `VK_IMAGE_ASPECT_PLANE_2_BIT`

- If either `oldLayout` or `newLayout` is `VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL` then `image` must have been created with `VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT` set

- If either `oldLayout` or `newLayout` is `VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL` then `image` must have been created with `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT` set

- If either `oldLayout` or `newLayout` is `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL` then `image` must have been created with `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT` set

- If either `oldLayout` or `newLayout` is `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL` then `image` must have been created with `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT` set

- If either `oldLayout` or `newLayout` is `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL` then `image` must have been created with `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT` set

- If either `oldLayout` or `newLayout` is `VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL` then `image` must have been created with `VK_IMAGE_USAGE_SAMPLED_BIT` or `VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT` set

- If either `oldLayout` or `newLayout` is `VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL` then `image` must have been created with `VK_IMAGE_USAGE_TRANSFER_SRC_BIT` set

- If either `oldLayout` or `newLayout` is `VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL` then `image` must have been created with `VK_IMAGE_USAGE_TRANSFER_DST_BIT` set

- If `image` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- If either `oldLayout` or `newLayout` is `VK_IMAGE_LAYOUT_SHADING_RATE_OPTIMAL_NV` then `image` must have been created with `VK_IMAGE_USAGE_SHADING_RATE_IMAGE_BIT_NV` set

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER`

- `pNext` must be `NULL` or a pointer to a valid instance of VkSampleLocationsInfoEXT

- The `sType` value of each struct in the `pNext` chain must be unique

- `oldLayout` must be a valid VkImageLayout value

- `newLayout` must be a valid VkImageLayout value

- `image` must be a valid VkImage handle

- `subresourceRange` must be a valid VkImageSubresourceRange structure

#### 6.7.4. Queue Family Ownership Transfer

Resources created with a VkSharingMode of `VK_SHARING_MODE_EXCLUSIVE` must have their ownership explicitly transferred from one queue family to another in order to access their content in a well-defined manner on a queue in a different queue family. Resources shared with external APIs or instances using external memory must also explicitly manage ownership transfers between local and external queues (or equivalent constructs in external APIs) regardless of the VkSharingMode specified when creating them. The special queue family index `VK_QUEUE_FAMILY_EXTERNAL` represents any queue external to the resource’s current Vulkan instance, as long as the queue uses the same underlying physical device or device group and uses the same driver version as the resource’s VkDevice, as indicated by VkPhysicalDeviceIDProperties::`deviceUUID` and VkPhysicalDeviceIDProperties::`driverUUID`. The special queue family index `VK_QUEUE_FAMILY_FOREIGN_EXT` represents any queue external to the resource’s current Vulkan instance, regardless of the queue’s underlying physical device or driver version. This includes, for example, queues for fixed-function image processing devices, media codec devices, and display devices, as well as all queues that use the same underlying physical device (or device group) and driver version as the resource’s VkDevice. If memory dependencies are correctly expressed between uses of such a resource between two queues in different families, but no ownership transfer is defined, the contents of that resource are undefined for any read accesses performed by the second queue family.

| Note If an application does not need the contents of a resource to remain valid when transferring from one queue family to another, then the ownership transfer should be skipped.

| Note Applications should expect transfers to/from `VK_QUEUE_FAMILY_FOREIGN_EXT` to be more expensive than transfers to/from `VK_QUEUE_FAMILY_EXTERNAL_KHR`.

A queue family ownership transfer consists of two distinct parts:

1. Release exclusive ownership from the source queue family

2. Acquire exclusive ownership for the destination queue family

An application must ensure that these operations occur in the correct order by defining an execution dependency between them, e.g. using a semaphore.

A release operation is used to release exclusive ownership of a range of a buffer or image subresource range. A release operation is defined by executing a buffer memory barrier (for a buffer range) or an image memory barrier (for an image subresource range) using vkCmdPipelineBarrier, on a queue from the source queue family. The `srcQueueFamilyIndex` parameter of the barrier must be set to the source queue family index, and the `dstQueueFamilyIndex` parameter to the destination queue family index. `dstAccessMask` is ignored for such a barrier, such that no visibility operation is executed - the value of this mask does not affect the validity of the barrier. The release operation happens-after the availability operation, and happens-before operations specified in the second synchronization scope of the calling command.

An acquire operation is used to acquire exclusive ownership of a range of a buffer or image subresource range. An acquire operation is defined by executing a buffer memory barrier (for a buffer range) or an image memory barrier (for an image subresource range) using vkCmdPipelineBarrier, on a queue from the destination queue family. The buffer range or image subresource range specified in an acquire operation must match exactly that of a previous release operation. The `srcQueueFamilyIndex` parameter of the barrier must be set to the source queue family index, and the `dstQueueFamilyIndex` parameter to the destination queue family index. `srcAccessMask` is ignored for such a barrier, such that no availability operation is executed - the value of this mask does not affect the validity of the barrier. The acquire operation happens-after operations in the first synchronization scope of the calling command, and happens-before the visibility operation.

| Note Whilst it is not invalid to provide destination or source access masks for memory barriers used for release or acquire operations, respectively, they have no practical effect. Access after a release operation has undefined results, and so visibility for those accesses has no practical effect. Similarly, write access before an acquire operation will produce undefined results for future access, so availability of those writes has no practical use. In an earlier version of the specification, these were required to match on both sides - but this was subsequently relaxed. These masks should be set to 0.

If the transfer is via an image memory barrier, and an image layout transition is desired, then the values of `oldLayout` and `newLayout` in the release operation's memory barrier must be equal to values of `oldLayout` and `newLayout` in the acquire operation's memory barrier. Although the image layout transition is submitted twice, it will only be executed once. A layout transition specified in this way happens-after the release operation and happens-before the acquire operation.

If the values of `srcQueueFamilyIndex` and `dstQueueFamilyIndex` are equal, no ownership transfer is performed, and the barrier operates as if they were both set to `VK_QUEUE_FAMILY_IGNORED`.

Queue family ownership transfers may perform read and write accesses on all memory bound to the image subresource or buffer range, so applications must ensure that all memory writes have been made available before a queue family ownership transfer is executed. Available memory is automatically made visible to queue family release and acquire operations, and writes performed by those operations are automatically made available.

Once a queue family has acquired ownership of a buffer range or image subresource range of a `VK_SHARING_MODE_EXCLUSIVE` resource, its contents are undefined to other queue families unless ownership is transferred. The contents of any portion of another resource which aliases memory that is bound to the transferred buffer or image subresource range are undefined after a release or acquire operation.

| Note Because events cannot be used directly for inter-queue synchronization, and because vkCmdSetEvent does not have the queue family index or memory barrier parameters needed by a release operation, the release and acquire operations of a queue family ownership transfer can only be performed using vkCmdPipelineBarrier.

### 6.8. Wait Idle Operations

To wait on the host for the completion of outstanding queue operations for a given queue, call:

    VkResult vkQueueWaitIdle(
        VkQueue                                     queue);

- `queue` is the queue on which to wait.

`vkQueueWaitIdle` is equivalent to submitting a fence to a queue and waiting with an infinite timeout for that fence to signal.

Valid Usage (Implicit)

- `queue` must be a valid VkQueue handle

Host Synchronization

- Host access to `queue` must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
- | - | Any | -

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_DEVICE_LOST`

To wait on the host for the completion of outstanding queue operations for all queues on a given logical device, call:

    VkResult vkDeviceWaitIdle(
        VkDevice                                    device);

- `device` is the logical device to idle.

`vkDeviceWaitIdle` is equivalent to calling `vkQueueWaitIdle` for all queues owned by `device`.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

Host Synchronization

- Host access to all `VkQueue` objects created from `device` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_DEVICE_LOST`

### 6.9. Host Write Ordering Guarantees

When batches of command buffers are submitted to a queue via vkQueueSubmit, it defines a memory dependency with prior host operations, and execution of command buffers submitted to the queue.

The first synchronization scope is defined by the host execution model, but includes execution of vkQueueSubmit on the host and anything that happened-before it.

The second synchronization scope includes all commands submitted in the same queue submission, and all commands that occur later in submission order.

The first access scope includes all host writes to mappable device memory that are available to the host memory domain.

The second access scope includes all memory access performed by the device.

### 6.10. Synchronization and Multiple Physical Devices

If a logical device includes more than one physical device, then fences, semaphores, and events all still have a single instance of the signaled state.

A fence becomes signaled when all physical devices complete the necessary queue operations.

Semaphore wait and signal operations all include a device index that is the sole physical device that performs the operation. These indices are provided in the VkDeviceGroupSubmitInfo and VkDeviceGroupBindSparseInfo structures. Semaphores are not exclusively owned by any physical device. For example, a semaphore can be signaled by one physical device and then waited on by a different physical device.

An event can only be waited on by the same physical device that signaled it (or the host).

### 6.11. Calibrated timestamps

In order to be able to correlate the time a particular operation took place at on timelines of different time domains (e.g. a device operation vs a host operation), Vulkan allows querying calibrated timestamps from multiple time domains.

To query calibrated timestamps from a set of time domains, call:

    VkResult vkGetCalibratedTimestampsEXT(
        VkDevice                                    device,
        uint32_t                                    timestampCount,
        const VkCalibratedTimestampInfoEXT*         pTimestampInfos,
        uint64_t*                                   pTimestamps,
        uint64_t*                                   pMaxDeviation);

- `device` is the logical device used to perform the query.

- `timestampCount` is the number of timestamps to query.

- `pTimestampInfos` is a pointer to an array of `timestampCount` VkCalibratedTimestampInfoEXT structures, describing the time domains the calibrated timestamps should be captured from.

- `pTimestamps` is a pointer to an array of `timestampCount` 64-bit unsigned integer values in which the requested calibrated timestamp values are returned.

- `pMaxDeviation` is a pointer to a 64-bit unsigned integer value in which the strictly positive maximum deviation, in nanoseconds, of the calibrated timestamp values is returned.

| Note The maximum deviation may vary between calls to `vkGetCalibratedTimestampsEXT` even for the same set of time domains due to implementation and platform specific reasons. It is the application’s responsibility to assess whether the returned maximum deviation makes the timestamp values suitable for any particular purpose and can choose to re-issue the timestamp calibration call pursuing a lower devation value.

Calibrated timestamp values can be extrapolated to estimate future coinciding timestamp values, however, depending on the nature of the time domains and other properties of the platform extrapolating values over a sufficiently long period of time may no longer be accurate enough to fit any particular purpose so applications are expected to re-calibrate the timestamps on a regular basis.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pTimestampInfos` must be a valid pointer to an array of `timestampCount` valid VkCalibratedTimestampInfoEXT structures

- `pTimestamps` must be a valid pointer to an array of `timestampCount` `uint64_t` values

- `pMaxDeviation` must be a valid pointer to a `uint64_t` value

- `timestampCount` must be greater than `0`

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkCalibratedTimestampInfoEXT` structure is defined as:

    typedef struct VkCalibratedTimestampInfoEXT {
        VkStructureType    sType;
        const void*        pNext;
        VkTimeDomainEXT    timeDomain;
    } VkCalibratedTimestampInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `timeDomain` is a VkTimeDomainEXT value specifying the time domain from which the calibrated timestamp value should be returned.

Valid Usage

- `timeDomain` must be one of the VkTimeDomainEXT values returned by vkGetPhysicalDeviceCalibrateableTimeDomainsEXT

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_CALIBRATED_TIMESTAMP_INFO_EXT`

- `pNext` must be `NULL`

- `timeDomain` must be a valid VkTimeDomainEXT value

The set of supported time domains consists of:

    typedef enum VkTimeDomainEXT {
        VK_TIME_DOMAIN_DEVICE_EXT = 0,
        VK_TIME_DOMAIN_CLOCK_MONOTONIC_EXT = 1,
        VK_TIME_DOMAIN_CLOCK_MONOTONIC_RAW_EXT = 2,
        VK_TIME_DOMAIN_QUERY_PERFORMANCE_COUNTER_EXT = 3,
        VK_TIME_DOMAIN_MAX_ENUM_EXT = 0x7FFFFFFF
    } VkTimeDomainEXT;

- `VK_TIME_DOMAIN_DEVICE_EXT` specifies the device time domain. Timestamp values in this time domain use the same units and are comparable with device timestamp values captured using vkCmdWriteTimestamp and are defined to be incrementing according to the timestampPeriod of the device.

- `VK_TIME_DOMAIN_CLOCK_MONOTONIC_EXT` specifies the CLOCK_MONOTONIC time domain available on POSIX platforms. Timestamp values in this time domain are in units of nanoseconds and are comparable with platform timestamp values captured using the POSIX clock_gettime API as computed by this example:

    struct timespec tv;
    clock_gettime(CLOCK_MONOTONIC, &tv);
    return tv.tv_nsec + tv.tv_sec*1000000000ull;

- `VK_TIME_DOMAIN_CLOCK_MONOTONIC_RAW_EXT` specifies the CLOCK_MONOTONIC_RAW time domain available on POSIX platforms. Timestamp values in this time domain are in units of nanoseconds and are comparable with platform timestamp values captured using the POSIX clock_gettime API as computed by this example:

    struct timespec tv;
    clock_gettime(CLOCK_MONOTONIC_RAW, &tv);
    return tv.tv_nsec + tv.tv_sec*1000000000ull;

- `VK_TIME_DOMAIN_QUERY_PERFORMANCE_COUNTER_EXT` specifies the performance counter (QPC) time domain available on Windows. Timestamp values in this time domain are in the same units as those provided by the Windows QueryPerformanceCounter API and are comparable with platform timestamp values captured using that API as computed by this example:

    LARGE_INTEGER counter;
    QueryPerformanceCounter(&counter);
    return counter.QuadPart;

## 7. Render Pass

A render pass represents a collection of attachments, subpasses, and dependencies between the subpasses, and describes how the attachments are used over the course of the subpasses. The use of a render pass in a command buffer is a render pass instance.

Render passes are represented by `VkRenderPass` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkRenderPass)

An attachment description describes the properties of an attachment including its format, sample count, and how its contents are treated at the beginning and end of each render pass instance.

A subpass represents a phase of rendering that reads and writes a subset of the attachments in a render pass. Rendering commands are recorded into a particular subpass of a render pass instance.

A subpass description describes the subset of attachments that is involved in the execution of a subpass. Each subpass can read from some attachments as input attachments, write to some as color attachments or depth/stencil attachments, and perform multisample resolve operations to resolve attachments. A subpass description can also include a set of preserve attachments, which are attachments that are not read or written by the subpass but whose contents must be preserved throughout the subpass.

A subpass uses an attachment if the attachment is a color, depth/stencil, resolve, depth/stencil resolve, or input attachment for that subpass (as determined by the `pColorAttachments`, `pDepthStencilAttachment`, `pResolveAttachments`, VkSubpassDescriptionDepthStencilResolve::`pDepthStencilResolveAttachment`, and `pInputAttachments` members of VkSubpassDescription, respectively). A subpass does not use an attachment if that attachment is preserved by the subpass. The first use of an attachment is in the lowest numbered subpass that uses that attachment. Similarly, the last use of an attachment is in the highest numbered subpass that uses that attachment.

The subpasses in a render pass all render to the same dimensions, and fragments for pixel (x,y,layer) in one subpass can only read attachment contents written by previous subpasses at that same (x,y,layer) location.

| Note By describing a complete set of subpasses in advance, render passes provide the implementation an opportunity to optimize the storage and transfer of attachment data between subpasses. In practice, this means that subpasses with a simple framebuffer-space dependency may be merged into a single tiled rendering pass, keeping the attachment data on-chip for the duration of a render pass instance. However, it is also quite common for a render pass to only contain a single subpass.

Subpass dependencies describe execution and memory dependencies between subpasses.

A subpass dependency chain is a sequence of subpass dependencies in a render pass, where the source subpass of each subpass dependency (after the first) equals the destination subpass of the previous dependency.

Execution of subpasses may overlap or execute out of order with regards to other subpasses, unless otherwise enforced by an execution dependency. Each subpass only respects submission order for commands recorded in the same subpass, and the vkCmdBeginRenderPass and vkCmdEndRenderPass commands that delimit the render pass - commands within other subpasses are not included. This affects most other implicit ordering guarantees.

A render pass describes the structure of subpasses and attachments independent of any specific image views for the attachments. The specific image views that will be used for the attachments, and their dimensions, are specified in `VkFramebuffer` objects. Framebuffers are created with respect to a specific render pass that the framebuffer is compatible with (see Render Pass Compatibility). Collectively, a render pass and a framebuffer define the complete render target state for one or more subpasses as well as the algorithmic dependencies between the subpasses.

The various pipeline stages of the drawing commands for a given subpass may execute concurrently and/or out of order, both within and across drawing commands, whilst still respecting pipeline order. However for a given (x,y,layer,sample) sample location, certain per-sample operations are performed in rasterization order.

### 7.1. Render Pass Creation

To create a render pass, call:

    VkResult vkCreateRenderPass(
        VkDevice                                    device,
        const VkRenderPassCreateInfo*               pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkRenderPass*                               pRenderPass);

- `device` is the logical device that creates the render pass.

- `pCreateInfo` is a pointer to a VkRenderPassCreateInfo structure describing the parameters of the render pass.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pRenderPass` is a pointer to a VkRenderPass handle in which the resulting render pass object is returned.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkRenderPassCreateInfo structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pRenderPass` must be a valid pointer to a VkRenderPass handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkRenderPassCreateInfo` structure is defined as:

    typedef struct VkRenderPassCreateInfo {
        VkStructureType                   sType;
        const void*                       pNext;
        VkRenderPassCreateFlags           flags;
        uint32_t                          attachmentCount;
        const VkAttachmentDescription*    pAttachments;
        uint32_t                          subpassCount;
        const VkSubpassDescription*       pSubpasses;
        uint32_t                          dependencyCount;
        const VkSubpassDependency*        pDependencies;
    } VkRenderPassCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkRenderPassCreateFlagBits

- `attachmentCount` is the number of attachments used by this render pass.

- `pAttachments` is a pointer to an array of `attachmentCount` VkAttachmentDescription structures describing the attachments used by the render pass.

- `subpassCount` is the number of subpasses to create.

- `pSubpasses` is a pointer to an array of `subpassCount` VkSubpassDescription structures describing each subpass.

- `dependencyCount` is the number of memory dependencies between pairs of subpasses.

- `pDependencies` is a pointer to an array of `dependencyCount` VkSubpassDependency structures describing dependencies between pairs of subpasses.

| Note Care should be taken to avoid a data race here; if any subpasses access attachments with overlapping memory locations, and one of those accesses is a write, a subpass dependency needs to be included between them.

Valid Usage

- If the `attachment` member of any element of `pInputAttachments`, `pColorAttachments`, `pResolveAttachments` or `pDepthStencilAttachment`, or any element of `pPreserveAttachments` in any element of `pSubpasses` is not `VK_ATTACHMENT_UNUSED`, it must be less than `attachmentCount`

- For any member of `pAttachments` with a `loadOp` equal to `VK_ATTACHMENT_LOAD_OP_CLEAR`, the first use of that attachment must not specify a `layout` equal to `VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL` or `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL`.

- For any member of `pAttachments` with a `stencilLoadOp` equal to `VK_ATTACHMENT_LOAD_OP_CLEAR`, the first use of that attachment must not specify a `layout` equal to `VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL` or `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL`.

- For any member of `pAttachments` with a `loadOp` equal to `VK_ATTACHMENT_LOAD_OP_CLEAR`, the first use of that attachment must not specify a `layout` equal to `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL`.

- For any member of `pAttachments` with a `stencilLoadOp` equal to `VK_ATTACHMENT_LOAD_OP_CLEAR`, the first use of that attachment must not specify a `layout` equal to `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL`.

- If the `pNext` chain includes a VkRenderPassInputAttachmentAspectCreateInfo structure, the `subpass` member of each element of its `pAspectReferences` member must be less than `subpassCount`

- If the `pNext` chain includes a VkRenderPassInputAttachmentAspectCreateInfo structure, the `inputAttachmentIndex` member of each element of its `pAspectReferences` member must be less than the value of `inputAttachmentCount` in the member of `pSubpasses` identified by its `subpass` member

- If the `pNext` chain includes a VkRenderPassInputAttachmentAspectCreateInfo structure, for any element of the `pInputAttachments` member of any element of `pSubpasses` where the `attachment` member is not `VK_ATTACHMENT_UNUSED`, the `aspectMask` member of the corresponding element of VkRenderPassInputAttachmentAspectCreateInfo::`pAspectReferences` must only include aspects that are present in images of the format specified by the element of `pAttachments` at `attachment`

- If the `pNext` chain includes a VkRenderPassMultiviewCreateInfo structure, and its `subpassCount` member is not zero, that member must be equal to the value of `subpassCount`

- If the `pNext` chain includes a VkRenderPassMultiviewCreateInfo structure, if its `dependencyCount` member is not zero, it must be equal to `dependencyCount`

- If the `pNext` chain includes a VkRenderPassMultiviewCreateInfo structure, for each non-zero element of `pViewOffsets`, the `srcSubpass` and `dstSubpass` members of `pDependencies` at the same index must not be equal

- If the `pNext` chain includes a VkRenderPassMultiviewCreateInfo structure, for any element of `pDependencies` with a `dependencyFlags` member that does not include `VK_DEPENDENCY_VIEW_LOCAL_BIT`, the corresponding element of the `pViewOffsets` member of that VkRenderPassMultiviewCreateInfo instance must be `0`

- If the `pNext` chain includes a VkRenderPassMultiviewCreateInfo structure, elements of its `pViewMasks` member must either all be `0`, or all not be `0`

- If the `pNext` chain includes a VkRenderPassMultiviewCreateInfo structure, and each element of its `pViewMasks` member is `0`, the `dependencyFlags` member of each element of `pDependencies` must not include `VK_DEPENDENCY_VIEW_LOCAL_BIT`

- If the `pNext` chain includes a VkRenderPassMultiviewCreateInfo structure, and each element of its `pViewMasks` member is `0`, `correlatedViewMaskCount` must be `0`

- If the `pNext` chain includes a VkRenderPassMultiviewCreateInfo structure, each element of its `pViewMask` member must not have a bit set at an index greater than or equal to VkPhysicalDeviceLimits::`maxFramebufferLayers`

- For any element of `pDependencies`, if the `srcSubpass` is not `VK_SUBPASS_EXTERNAL`, all stage flags included in the `srcStageMask` member of that dependency must be a pipeline stage supported by the pipeline identified by the `pipelineBindPoint` member of the source subpass

- For any element of `pDependencies`, if the `dstSubpass` is not `VK_SUBPASS_EXTERNAL`, all stage flags included in the `dstStageMask` member of that dependency must be a pipeline stage supported by the pipeline identified by the `pipelineBindPoint` member of the destination subpass

- The `srcSubpass` member of each element of `pDependencies` must be less than `subpassCount`

- The `dstSubpass` member of each element of `pDependencies` must be less than `subpassCount`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkRenderPassFragmentDensityMapCreateInfoEXT, VkRenderPassInputAttachmentAspectCreateInfo, or VkRenderPassMultiviewCreateInfo

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be a valid combination of VkRenderPassCreateFlagBits values

- If `attachmentCount` is not `0`, `pAttachments` must be a valid pointer to an array of `attachmentCount` valid VkAttachmentDescription structures

- `pSubpasses` must be a valid pointer to an array of `subpassCount` valid VkSubpassDescription structures

- If `dependencyCount` is not `0`, `pDependencies` must be a valid pointer to an array of `dependencyCount` valid VkSubpassDependency structures

- `subpassCount` must be greater than `0`

Bits which can be set in VkRenderPassCreateInfo::`flags` describing additional properties of the render pass are:

    typedef enum VkRenderPassCreateFlagBits {
        VK_RENDER_PASS_CREATE_TRANSFORM_BIT_QCOM = 0x00000002,
        VK_RENDER_PASS_CREATE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkRenderPassCreateFlagBits;

- `VK_RENDER_PASS_CREATE_TRANSFORM_BIT_QCOM` specifies that the created renderpass is compatible with render pass transform.

If the `VkRenderPassCreateInfo`::`pNext` chain includes a `VkRenderPassMultiviewCreateInfo` structure, then that structure includes an array of view masks, view offsets, and correlation masks for the render pass.

The `VkRenderPassMultiviewCreateInfo` structure is defined as:

    typedef struct VkRenderPassMultiviewCreateInfo {
        VkStructureType    sType;
        const void*        pNext;
        uint32_t           subpassCount;
        const uint32_t*    pViewMasks;
        uint32_t           dependencyCount;
        const int32_t*     pViewOffsets;
        uint32_t           correlationMaskCount;
        const uint32_t*    pCorrelationMasks;
    } VkRenderPassMultiviewCreateInfo;

or the equivalent

    typedef VkRenderPassMultiviewCreateInfo VkRenderPassMultiviewCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `subpassCount` is zero or the number of subpasses in the render pass.

- `pViewMasks` is a pointer to an array of `subpassCount` view masks, where each mask is a bitfield of view indices describing which views rendering is broadcast to in each subpass, when multiview is enabled. If `subpassCount` is zero, each view mask is treated as zero.

- `dependencyCount` is zero or the number of dependencies in the render pass.

- `pViewOffsets` is a pointer to an array of `dependencyCount` view offsets, one for each dependency. If `dependencyCount` is zero, each dependency’s view offset is treated as zero. Each view offset controls which views in the source subpass the views in the destination subpass depend on.

- `correlationMaskCount` is zero or the number of correlation masks.

- `pCorrelationMasks` is a pointer to an array of `correlationMaskCount` view masks indicating sets of views that may be more efficient to render concurrently.

When a subpass uses a non-zero view mask, multiview functionality is considered to be enabled. Multiview is all-or-nothing for a render pass - that is, either all subpasses must have a non-zero view mask (though some subpasses may have only one view) or all must be zero. Multiview causes all drawing and clear commands in the subpass to behave as if they were broadcast to each view, where a view is represented by one layer of the framebuffer attachments. All draws and clears are broadcast to each view index whose bit is set in the view mask. The view index is provided in the `ViewIndex` shader input variable, and color, depth/stencil, and input attachments all read/write the layer of the framebuffer corresponding to the view index.

If the view mask is zero for all subpasses, multiview is considered to be disabled and all drawing commands execute normally, without this additional broadcasting.

Some implementations may not support multiview in conjunction with geometry shaders or tessellation shaders.

When multiview is enabled, the `VK_DEPENDENCY_VIEW_LOCAL_BIT` bit in a dependency can be used to express a view-local dependency, meaning that each view in the destination subpass depends on a single view in the source subpass. Unlike pipeline barriers, a subpass dependency can potentially have a different view mask in the source subpass and the destination subpass. If the dependency is view-local, then each view (dstView) in the destination subpass depends on the view dstView + `pViewOffsets`[dependency] in the source subpass. If there is not such a view in the source subpass, then this dependency does not affect that view in the destination subpass. If the dependency is not view-local, then all views in the destination subpass depend on all views in the source subpass, and the view offset is ignored. A non-zero view offset is not allowed in a self-dependency.

The elements of `pCorrelationMasks` are a set of masks of views indicating that views in the same mask may exhibit spatial coherency between the views, making it more efficient to render them concurrently. Correlation masks must not have a functional effect on the results of the multiview rendering.

When multiview is enabled, at the beginning of each subpass all non-render pass state is undefined. In particular, each time vkCmdBeginRenderPass or vkCmdNextSubpass is called the graphics pipeline must be bound, any relevant descriptor sets or vertex/index buffers must be bound, and any relevant dynamic state or push constants must be set before they are used.

A multiview subpass can declare that its shaders will write per-view attributes for all views in a single invocation, by setting the `VK_SUBPASS_DESCRIPTION_PER_VIEW_ATTRIBUTES_BIT_NVX` bit in the subpass description. The only supported per-view attributes are position and viewport mask, and per-view position and viewport masks are written to output array variables decorated with `PositionPerViewNV` and `ViewportMaskPerViewNV`, respectively. If `VK_NV_viewport_array2` is not supported and enabled, `ViewportMaskPerViewNV` must not be used. Values written to elements of `PositionPerViewNV` and `ViewportMaskPerViewNV` must not depend on the `ViewIndex`. The shader must also write to an output variable decorated with `Position`, and the value written to `Position` must equal the value written to `PositionPerViewNV`[`ViewIndex`]. Similarly, if `ViewportMaskPerViewNV` is written to then the shader must also write to an output variable decorated with `ViewportMaskNV`, and the value written to `ViewportMaskNV` must equal the value written to `ViewportMaskPerViewNV`[`ViewIndex`]. Implementations will either use values taken from `Position` and `ViewportMaskNV` and invoke the shader once for each view, or will use values taken from `PositionPerViewNV` and `ViewportMaskPerViewNV` and invoke the shader fewer times. The values written to `Position` and `ViewportMaskNV` must not depend on the values written to `PositionPerViewNV` and `ViewportMaskPerViewNV`, or vice versa (to allow compilers to eliminate the unused outputs). All attributes that do not have `*PerViewNV` counterparts must not depend on `ViewIndex`.

Per-view attributes are all-or-nothing for a subpass. That is, all pipelines compiled against a subpass that includes the `VK_SUBPASS_DESCRIPTION_PER_VIEW_ATTRIBUTES_BIT_NVX` bit must write per-view attributes to the `*PerViewNV[]` shader outputs, in addition to the non-per-view (e.g. `Position`) outputs. Pipelines compiled against a subpass that does not include this bit must not include the `*PerViewNV[]` outputs in their interfaces.

Valid Usage

- Each view index must not be set in more than one element of `pCorrelationMasks`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_RENDER_PASS_MULTIVIEW_CREATE_INFO`

- If `subpassCount` is not `0`, `pViewMasks` must be a valid pointer to an array of `subpassCount` `uint32_t` values

- If `dependencyCount` is not `0`, `pViewOffsets` must be a valid pointer to an array of `dependencyCount` `int32_t` values

- If `correlationMaskCount` is not `0`, `pCorrelationMasks` must be a valid pointer to an array of `correlationMaskCount` `uint32_t` values

If the `VkRenderPassCreateInfo`::`pNext` chain includes a `VkRenderPassFragmentDensityMapCreateInfoEXT` structure, then that structure includes a fragment density map attachment for the render pass.

The `VkRenderPassFragmentDensityMapCreateInfoEXT` structure is defined as:

    typedef struct VkRenderPassFragmentDensityMapCreateInfoEXT {
        VkStructureType          sType;
        const void*              pNext;
        VkAttachmentReference    fragmentDensityMapAttachment;
    } VkRenderPassFragmentDensityMapCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `fragmentDensityMapAttachment` is the fragment density map to use for the render pass.

The fragment density map attachment is read at an implementation-dependent time either by the host during vkCmdBeginRenderPass if the attachment’s image view was not created with `flags` containing `VK_IMAGE_VIEW_CREATE_FRAGMENT_DENSITY_MAP_DYNAMIC_BIT_EXT`, or by the device when drawing commands in the renderpass execute `VK_PIPELINE_STAGE_FRAGMENT_DENSITY_PROCESS_BIT_EXT`.

If this structure is not present, it is as if `fragmentDensityMapAttachment` was given as `VK_ATTACHMENT_UNUSED`.

Valid Usage

- If `fragmentDensityMapAttachment` is not `VK_ATTACHMENT_UNUSED`, `fragmentDensityMapAttachment` must be less than `VkRenderPassCreateInfo`::`attachmentCount`

- If `fragmentDensityMapAttachment` is not `VK_ATTACHMENT_UNUSED`, `fragmentDensityMapAttachment` must not be an element of `VkSubpassDescription`::`pInputAttachments`, `VkSubpassDescription`::`pColorAttachments`, `VkSubpassDescription`::`pResolveAttachments`, `VkSubpassDescription`::`pDepthStencilAttachment`, or `VkSubpassDescription`::`pPreserveAttachments` for any subpass

- If `fragmentDensityMapAttachment` is not `VK_ATTACHMENT_UNUSED`, `layout` must be equal to `VK_IMAGE_LAYOUT_FRAGMENT_DENSITY_MAP_OPTIMAL_EXT`, or `VK_IMAGE_LAYOUT_GENERAL`

- If `fragmentDensityMapAttachment` is not `VK_ATTACHMENT_UNUSED`, `fragmentDensityMapAttachment` must reference an attachment with a `loadOp` equal to `VK_ATTACHMENT_LOAD_OP_LOAD` or `VK_ATTACHMENT_LOAD_OP_DONT_CARE`.

- If `fragmentDensityMapAttachment` is not `VK_ATTACHMENT_UNUSED`, `fragmentDensityMapAttachment` must reference an attachment with a `storeOp` equal to `VK_ATTACHMENT_STORE_OP_DONT_CARE`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_RENDER_PASS_FRAGMENT_DENSITY_MAP_CREATE_INFO_EXT`

- `fragmentDensityMapAttachment` must be a valid VkAttachmentReference structure

The `VkAttachmentDescription` structure is defined as:

    typedef struct VkAttachmentDescription {
        VkAttachmentDescriptionFlags    flags;
        VkFormat                        format;
        VkSampleCountFlagBits           samples;
        VkAttachmentLoadOp              loadOp;
        VkAttachmentStoreOp             storeOp;
        VkAttachmentLoadOp              stencilLoadOp;
        VkAttachmentStoreOp             stencilStoreOp;
        VkImageLayout                   initialLayout;
        VkImageLayout                   finalLayout;
    } VkAttachmentDescription;

- `flags` is a bitmask of VkAttachmentDescriptionFlagBits specifying additional properties of the attachment.

- `format` is a VkFormat value specifying the format of the image view that will be used for the attachment.

- `samples` is the number of samples of the image as defined in VkSampleCountFlagBits.

- `loadOp` is a VkAttachmentLoadOp value specifying how the contents of color and depth components of the attachment are treated at the beginning of the subpass where it is first used.

- `storeOp` is a VkAttachmentStoreOp value specifying how the contents of color and depth components of the attachment are treated at the end of the subpass where it is last used.

- `stencilLoadOp` is a VkAttachmentLoadOp value specifying how the contents of stencil components of the attachment are treated at the beginning of the subpass where it is first used.

- `stencilStoreOp` is a VkAttachmentStoreOp value specifying how the contents of stencil components of the attachment are treated at the end of the last subpass where it is used.

- `initialLayout` is the layout the attachment image subresource will be in when a render pass instance begins.

- `finalLayout` is the layout the attachment image subresource will be transitioned to when a render pass instance ends.

If the attachment uses a color format, then `loadOp` and `storeOp` are used, and `stencilLoadOp` and `stencilStoreOp` are ignored. If the format has depth and/or stencil components, `loadOp` and `storeOp` apply only to the depth data, while `stencilLoadOp` and `stencilStoreOp` define how the stencil data is handled. `loadOp` and `stencilLoadOp` define the load operations that execute as part of the first subpass that uses the attachment. `storeOp` and `stencilStoreOp` define the store operations that execute as part of the last subpass that uses the attachment.

The load operation for each sample in an attachment happens-before any recorded command which accesses the sample in the first subpass where the attachment is used. Load operations for attachments with a depth/stencil format execute in the `VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT` pipeline stage. Load operations for attachments with a color format execute in the `VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT` pipeline stage.

The store operation for each sample in an attachment happens-after any recorded command which accesses the sample in the last subpass where the attachment is used. Store operations for attachments with a depth/stencil format execute in the `VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT` pipeline stage. Store operations for attachments with a color format execute in the `VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT` pipeline stage.

If an attachment is not used by any subpass, then `loadOp`, `storeOp`, `stencilStoreOp`, and `stencilLoadOp` are ignored, and the attachment’s memory contents will not be modified by execution of a render pass instance.

The load and store operations apply on the first and last use of each view in the render pass, respectively. If a view index of an attachment is not included in the view mask in any subpass that uses it, then the load and store operations are ignored, and the attachment’s memory contents will not be modified by execution of a render pass instance.

During a render pass instance, input/color attachments with color formats that have a component size of 8, 16, or 32 bits must be represented in the attachment’s format throughout the instance. Attachments with other floating- or fixed-point color formats, or with depth components may be represented in a format with a precision higher than the attachment format, but must be represented with the same range. When such a component is loaded via the `loadOp`, it will be converted into an implementation-dependent format used by the render pass. Such components must be converted from the render pass format, to the format of the attachment, before they are resolved or stored at the end of a render pass instance via `storeOp`. Conversions occur as described in Numeric Representation and Computation and Fixed-Point Data Conversions.

If `flags` includes `VK_ATTACHMENT_DESCRIPTION_MAY_ALIAS_BIT`, then the attachment is treated as if it shares physical memory with another attachment in the same render pass. This information limits the ability of the implementation to reorder certain operations (like layout transitions and the `loadOp`) such that it is not improperly reordered against other uses of the same physical memory via a different attachment. This is described in more detail below.

If a render pass uses multiple attachments that alias the same device memory, those attachments must each include the `VK_ATTACHMENT_DESCRIPTION_MAY_ALIAS_BIT` bit in their attachment description flags. Attachments aliasing the same memory occurs in multiple ways:

- Multiple attachments being assigned the same image view as part of framebuffer creation.

- Attachments using distinct image views that correspond to the same image subresource of an image.

- Attachments using views of distinct image subresources which are bound to overlapping memory ranges.

| Note Render passes must include subpass dependencies (either directly or via a subpass dependency chain) between any two subpasses that operate on the same attachment or aliasing attachments and those subpass dependencies must include execution and memory dependencies separating uses of the aliases, if at least one of those subpasses writes to one of the aliases. These dependencies must not include the `VK_DEPENDENCY_BY_REGION_BIT` if the aliases are views of distinct image subresources which overlap in memory.

Multiple attachments that alias the same memory must not be used in a single subpass. A given attachment index must not be used multiple times in a single subpass, with one exception: two subpass attachments can use the same attachment index if at least one use is as an input attachment and neither use is as a resolve or preserve attachment. In other words, the same view can be used simultaneously as an input and color or depth/stencil attachment, but must not be used as multiple color or depth/stencil attachments nor as resolve or preserve attachments. The precise set of valid scenarios is described in more detail below.

If a set of attachments alias each other, then all except the first to be used in the render pass must use an `initialLayout` of `VK_IMAGE_LAYOUT_UNDEFINED`, since the earlier uses of the other aliases make their contents undefined. Once an alias has been used and a different alias has been used after it, the first alias must not be used in any later subpasses. However, an application can assign the same image view to multiple aliasing attachment indices, which allows that image view to be used multiple times even if other aliases are used in between.

| Note Once an attachment needs the `VK_ATTACHMENT_DESCRIPTION_MAY_ALIAS_BIT` bit, there should be no additional cost of introducing additional aliases, and using these additional aliases may allow more efficient clearing of the attachments on multiple uses via `VK_ATTACHMENT_LOAD_OP_CLEAR`.

Valid Usage

- `finalLayout` must not be `VK_IMAGE_LAYOUT_UNDEFINED` or `VK_IMAGE_LAYOUT_PREINITIALIZED`

- If `format` is a color format, `initialLayout` must not be `VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL`, or `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL`

- If `format` is a depth/stencil format, `initialLayout` must not be `VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL`

- If `format` is a color format, `finalLayout` must not be `VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL`, or `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL`

- If `format` is a depth/stencil format, `finalLayout` must not be `VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL`

- If the `separateDepthStencilLayouts` feature is not enabled, `initialLayout` must not be `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL`, or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL`

- If the `separateDepthStencilLayouts` feature is not enabled, `finalLayout` must not be `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL`, or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL`

- If `format` is a color format, `initialLayout` must not be `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL`, or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL`

- If `format` is a color format, `finalLayout` must not be `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL`, or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL`

- If `format` is a depth/stencil format which includes both depth and stencil aspects, `initialLayout` must not be `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL`, or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL`

- If `format` is a depth/stencil format which includes both depth and stencil aspects, `finalLayout` must not be `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL`, or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL`

- If `format` is a depth/stencil format which includes only the depth aspect, `initialLayout` must not be `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL` or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL`

- If `format` is a depth/stencil format which includes only the depth aspect, `finalLayout` must not be `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL` or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL`

- If `format` is a depth/stencil format which includes only the stencil aspect, `initialLayout` must not be `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL` or `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`

- If `format` is a depth/stencil format which includes only the stencil aspect, `finalLayout` must not be `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL` or `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`

Valid Usage (Implicit)

- `flags` must be a valid combination of VkAttachmentDescriptionFlagBits values

- `format` must be a valid VkFormat value

- `samples` must be a valid VkSampleCountFlagBits value

- `loadOp` must be a valid VkAttachmentLoadOp value

- `storeOp` must be a valid VkAttachmentStoreOp value

- `stencilLoadOp` must be a valid VkAttachmentLoadOp value

- `stencilStoreOp` must be a valid VkAttachmentStoreOp value

- `initialLayout` must be a valid VkImageLayout value

- `finalLayout` must be a valid VkImageLayout value

Bits which can be set in VkAttachmentDescription::`flags` describing additional properties of the attachment are:

    typedef enum VkAttachmentDescriptionFlagBits {
        VK_ATTACHMENT_DESCRIPTION_MAY_ALIAS_BIT = 0x00000001,
        VK_ATTACHMENT_DESCRIPTION_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkAttachmentDescriptionFlagBits;

- `VK_ATTACHMENT_DESCRIPTION_MAY_ALIAS_BIT` specifies that the attachment aliases the same device memory as other attachments.

    typedef VkFlags VkAttachmentDescriptionFlags;

`VkAttachmentDescriptionFlags` is a bitmask type for setting a mask of zero or more VkAttachmentDescriptionFlagBits.

Possible values of VkAttachmentDescription::`loadOp` and `stencilLoadOp`, specifying how the contents of the attachment are treated, are:

    typedef enum VkAttachmentLoadOp {
        VK_ATTACHMENT_LOAD_OP_LOAD = 0,
        VK_ATTACHMENT_LOAD_OP_CLEAR = 1,
        VK_ATTACHMENT_LOAD_OP_DONT_CARE = 2,
        VK_ATTACHMENT_LOAD_OP_MAX_ENUM = 0x7FFFFFFF
    } VkAttachmentLoadOp;

- `VK_ATTACHMENT_LOAD_OP_LOAD` specifies that the previous contents of the image within the render area will be preserved. For attachments with a depth/stencil format, this uses the access type `VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_READ_BIT`. For attachments with a color format, this uses the access type `VK_ACCESS_COLOR_ATTACHMENT_READ_BIT`.

- `VK_ATTACHMENT_LOAD_OP_CLEAR` specifies that the contents within the render area will be cleared to a uniform value, which is specified when a render pass instance is begun. For attachments with a depth/stencil format, this uses the access type `VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT`. For attachments with a color format, this uses the access type `VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT`.

- `VK_ATTACHMENT_LOAD_OP_DONT_CARE` specifies that the previous contents within the area need not be preserved; the contents of the attachment will be undefined inside the render area. For attachments with a depth/stencil format, this uses the access type `VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT`. For attachments with a color format, this uses the access type `VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT`.

Possible values of VkAttachmentDescription::`storeOp` and `stencilStoreOp`, specifying how the contents of the attachment are treated, are:

    typedef enum VkAttachmentStoreOp {
        VK_ATTACHMENT_STORE_OP_STORE = 0,
        VK_ATTACHMENT_STORE_OP_DONT_CARE = 1,
        VK_ATTACHMENT_STORE_OP_MAX_ENUM = 0x7FFFFFFF
    } VkAttachmentStoreOp;

- `VK_ATTACHMENT_STORE_OP_STORE` specifies the contents generated during the render pass and within the render area are written to memory. For attachments with a depth/stencil format, this uses the access type `VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT`. For attachments with a color format, this uses the access type `VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT`.

- `VK_ATTACHMENT_STORE_OP_DONT_CARE` specifies the contents within the render area are not needed after rendering, and may be discarded; the contents of the attachment will be undefined inside the render area. For attachments with a depth/stencil format, this uses the access type `VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT`. For attachments with a color format, this uses the access type `VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT`.

| Note `VK_ATTACHMENT_STORE_OP_DONT_CARE` can cause contents generated during previous render passes to be discarded before reaching memory, even if no write to the attachment occurs during the current render pass.

To specify which aspects of an input attachment can be read, add a VkRenderPassInputAttachmentAspectCreateInfo structure to the `pNext` chain of the VkRenderPassCreateInfo structure:

The `VkRenderPassInputAttachmentAspectCreateInfo` structure is defined as:

    typedef struct VkRenderPassInputAttachmentAspectCreateInfo {
        VkStructureType                            sType;
        const void*                                pNext;
        uint32_t                                   aspectReferenceCount;
        const VkInputAttachmentAspectReference*    pAspectReferences;
    } VkRenderPassInputAttachmentAspectCreateInfo;

or the equivalent

    typedef VkRenderPassInputAttachmentAspectCreateInfo VkRenderPassInputAttachmentAspectCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `aspectReferenceCount` is the number of elements in the `pAspectReferences` array.

- `pAspectReferences` is a pointer to an array of `aspectReferenceCount` VkInputAttachmentAspectReference structures containing a mask describing which aspect(s) can be accessed for a given input attachment within a given subpass.

An application can access any aspect of an input attachment that does not have a specified aspect mask in the `pAspectReferences` array. Otherwise, an application must not access aspect(s) of an input attachment other than those in its specified aspect mask.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_RENDER_PASS_INPUT_ATTACHMENT_ASPECT_CREATE_INFO`

- `pAspectReferences` must be a valid pointer to an array of `aspectReferenceCount` valid VkInputAttachmentAspectReference structures

- `aspectReferenceCount` must be greater than `0`

The `VkInputAttachmentAspectReference` structure specifies an aspect mask for a specific input attachment of a specific subpass in the render pass.

`subpass` and `inputAttachmentIndex` index into the render pass as:

`pCreateInfo->pSubpasses`[subpass].pInputAttachments[inputAttachmentIndex]

    typedef struct VkInputAttachmentAspectReference {
        uint32_t              subpass;
        uint32_t              inputAttachmentIndex;
        VkImageAspectFlags    aspectMask;
    } VkInputAttachmentAspectReference;

or the equivalent

    typedef VkInputAttachmentAspectReference VkInputAttachmentAspectReferenceKHR;

- `subpass` is an index into the `pSubpasses` array of the parent `VkRenderPassCreateInfo` structure.

- `inputAttachmentIndex` is an index into the `pInputAttachments` of the specified subpass.

- `aspectMask` is a mask of which aspect(s) can be accessed within the specified subpass.

Valid Usage

- `aspectMask` must not include `VK_IMAGE_ASPECT_METADATA_BIT`

- `aspectMask` must not include `VK_IMAGE_ASPECT_MEMORY_PLANE_i_BIT_EXT` for any index `i`.

Valid Usage (Implicit)

- `aspectMask` must be a valid combination of VkImageAspectFlagBits values

- `aspectMask` must not be `0`

The `VkSubpassDescription` structure is defined as:

    typedef struct VkSubpassDescription {
        VkSubpassDescriptionFlags       flags;
        VkPipelineBindPoint             pipelineBindPoint;
        uint32_t                        inputAttachmentCount;
        const VkAttachmentReference*    pInputAttachments;
        uint32_t                        colorAttachmentCount;
        const VkAttachmentReference*    pColorAttachments;
        const VkAttachmentReference*    pResolveAttachments;
        const VkAttachmentReference*    pDepthStencilAttachment;
        uint32_t                        preserveAttachmentCount;
        const uint32_t*                 pPreserveAttachments;
    } VkSubpassDescription;

- `flags` is a bitmask of VkSubpassDescriptionFlagBits specifying usage of the subpass.

- `pipelineBindPoint` is a VkPipelineBindPoint value specifying the pipeline type supported for this subpass.

- `inputAttachmentCount` is the number of input attachments.

- `pInputAttachments` is a pointer to an array of VkAttachmentReference structures defining the input attachments for this subpass and their layouts.

- `colorAttachmentCount` is the number of color attachments.

- `pColorAttachments` is a pointer to an array of VkAttachmentReference structures defining the color attachments for this subpass and their layouts.

- `pResolveAttachments` is an optional array of `colorAttachmentCount` VkAttachmentReference structures defining the resolve attachments for this subpass and their layouts.

- `pDepthStencilAttachment` is a pointer to a VkAttachmentReference structure specifying the depth/stencil attachment for this subpass and its layout.

- `preserveAttachmentCount` is the number of preserved attachments.

- `pPreserveAttachments` is a pointer to an array of `preserveAttachmentCount` render pass attachment indices identifying attachments that are not used by this subpass, but whose contents must be preserved throughout the subpass.

Each element of the `pInputAttachments` array corresponds to an input attachment index in a fragment shader, i.e. if a shader declares an image variable decorated with a `InputAttachmentIndex` value of X, then it uses the attachment provided in `pInputAttachments`[X]. Input attachments must also be bound to the pipeline in a descriptor set. If the `attachment` member of any element of `pInputAttachments` is `VK_ATTACHMENT_UNUSED`, the application must not read from the corresponding input attachment index. Fragment shaders can use subpass input variables to access the contents of an input attachment at the fragment’s (x, y, layer) framebuffer coordinates. Input attachments must not be used by any subpasses within a renderpass that enables render pass transform.

Each element of the `pColorAttachments` array corresponds to an output location in the shader, i.e. if the shader declares an output variable decorated with a `Location` value of X, then it uses the attachment provided in `pColorAttachments`[X]. If the `attachment` member of any element of `pColorAttachments` is `VK_ATTACHMENT_UNUSED`, writes to the corresponding location by a fragment are discarded.

If `pResolveAttachments` is not `NULL`, each of its elements corresponds to a color attachment (the element in `pColorAttachments` at the same index), and a multisample resolve operation is defined for each attachment. At the end of each subpass, multisample resolve operations read the subpass’s color attachments, and resolve the samples for each pixel within the render area to the same pixel location in the corresponding resolve attachments, unless the resolve attachment index is `VK_ATTACHMENT_UNUSED`.

Similarly, if VkSubpassDescriptionDepthStencilResolve::`pDepthStencilResolveAttachment` is not `NULL` and does not have the value `VK_ATTACHMENT_UNUSED`, it corresponds to the depth/stencil attachment in `pDepthStencilAttachment`, and multisample resolve operations for depth and stencil are defined by VkSubpassDescriptionDepthStencilResolve::`depthResolveMode` and VkSubpassDescriptionDepthStencilResolve::`stencilResolveMode`, respectively. At the end of each subpass, multisample resolve operations read the subpass’s depth/stencil attachment, and resolve the samples for each pixel to the same pixel location in the corresponding resolve attachment. If VkSubpassDescriptionDepthStencilResolve::`depthResolveMode` is `VK_RESOLVE_MODE_NONE`, then the depth component of the resolve attachment is not written to and its contents are preserved. Similarly, if VkSubpassDescriptionDepthStencilResolve::`stencilResolveMode` is `VK_RESOLVE_MODE_NONE`, then the stencil component of the resolve attachment is not written to and its contents are preserved. VkSubpassDescriptionDepthStencilResolve::`depthResolveMode` is ignored if the VkFormat of the `pDepthStencilResolveAttachment` does not have a depth component. Similarly, VkSubpassDescriptionDepthStencilResolve::`stencilResolveMode` is ignored if the VkFormat of the `pDepthStencilResolveAttachment` does not have a stencil component.

If the image subresource range referenced by the depth/stencil attachment is created with `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT`, then the multisample resolve operation uses the sample locations state specified in the `sampleLocationsInfo` member of the element of the `VkRenderPassSampleLocationsBeginInfoEXT`::`pPostSubpassSampleLocations` for the subpass.

If `pDepthStencilAttachment` is `NULL`, or if its attachment index is `VK_ATTACHMENT_UNUSED`, it indicates that no depth/stencil attachment will be used in the subpass.

The contents of an attachment within the render area become undefined at the start of a subpass S if all of the following conditions are true:

- The attachment is used as a color, depth/stencil, or resolve attachment in any subpass in the render pass.

- There is a subpass S1 that uses or preserves the attachment, and a subpass dependency from S1 to S.

- The attachment is not used or preserved in subpass S.

Once the contents of an attachment become undefined in subpass S, they remain undefined for subpasses in subpass dependency chains starting with subpass S until they are written again. However, they remain valid for subpasses in other subpass dependency chains starting with subpass S1 if those subpasses use or preserve the attachment.

Valid Usage

- `pipelineBindPoint` must be `VK_PIPELINE_BIND_POINT_GRAPHICS`

- `colorAttachmentCount` must be less than or equal to `VkPhysicalDeviceLimits`::`maxColorAttachments`

- If the first use of an attachment in this render pass is as an input attachment, and the attachment is not also used as a color or depth/stencil attachment in the same subpass, then `loadOp` must not be `VK_ATTACHMENT_LOAD_OP_CLEAR`

- If `pResolveAttachments` is not `NULL`, for each resolve attachment that is not `VK_ATTACHMENT_UNUSED`, the corresponding color attachment must not be `VK_ATTACHMENT_UNUSED`

- If `pResolveAttachments` is not `NULL`, for each resolve attachment that is not `VK_ATTACHMENT_UNUSED`, the corresponding color attachment must not have a sample count of `VK_SAMPLE_COUNT_1_BIT`

- If `pResolveAttachments` is not `NULL`, each resolve attachment that is not `VK_ATTACHMENT_UNUSED` must have a sample count of `VK_SAMPLE_COUNT_1_BIT`

- If `pResolveAttachments` is not `NULL`, each resolve attachment that is not `VK_ATTACHMENT_UNUSED` must have the same VkFormat as its corresponding color attachment

- All attachments in `pColorAttachments` that are not `VK_ATTACHMENT_UNUSED` must have the same sample count

- All attachments in `pInputAttachments` that are not `VK_ATTACHMENT_UNUSED` must have formats whose features contain at least one of `VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT` or `VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT`.

- All attachments in `pColorAttachments` that are not `VK_ATTACHMENT_UNUSED` must have formats whose features contain `VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT`

- All attachments in `pResolveAttachments` that are not `VK_ATTACHMENT_UNUSED` must have formats whose features contain `VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT`

- If `pDepthStencilAttachment` is not `NULL` and the attachment is not `VK_ATTACHMENT_UNUSED` then it must have a format whose features contain `VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT`

- If the `VK_AMD_mixed_attachment_samples` extension is enabled, and all attachments in `pColorAttachments` that are not `VK_ATTACHMENT_UNUSED` must have a sample count that is smaller than or equal to the sample count of `pDepthStencilAttachment` if it is not `VK_ATTACHMENT_UNUSED`

- If neither the `VK_AMD_mixed_attachment_samples` nor the `VK_NV_framebuffer_mixed_samples` extensions are enabled, and if `pDepthStencilAttachment` is not `VK_ATTACHMENT_UNUSED` and any attachments in `pColorAttachments` are not `VK_ATTACHMENT_UNUSED`, they must have the same sample count

- The `attachment` member of each element of `pPreserveAttachments` must not be `VK_ATTACHMENT_UNUSED`

- Each element of `pPreserveAttachments` must not also be an element of any other member of the subpass description

- If any attachment is used by more than one VkAttachmentReference member, then each use must use the same `layout`

- If `flags` includes `VK_SUBPASS_DESCRIPTION_PER_VIEW_POSITION_X_ONLY_BIT_NVX`, it must also include `VK_SUBPASS_DESCRIPTION_PER_VIEW_ATTRIBUTES_BIT_NVX`.

- If the render pass is created with `VK_RENDER_PASS_CREATE_TRANSFORM_BIT_QCOM` each of the elements of `pInputAttachments` must be `VK_ATTACHMENT_UNUSED`.

Valid Usage (Implicit)

- `flags` must be a valid combination of VkSubpassDescriptionFlagBits values

- `pipelineBindPoint` must be a valid VkPipelineBindPoint value

- If `inputAttachmentCount` is not `0`, `pInputAttachments` must be a valid pointer to an array of `inputAttachmentCount` valid VkAttachmentReference structures

- If `colorAttachmentCount` is not `0`, `pColorAttachments` must be a valid pointer to an array of `colorAttachmentCount` valid VkAttachmentReference structures

- If `colorAttachmentCount` is not `0`, and `pResolveAttachments` is not `NULL`, `pResolveAttachments` must be a valid pointer to an array of `colorAttachmentCount` valid VkAttachmentReference structures

- If `pDepthStencilAttachment` is not `NULL`, `pDepthStencilAttachment` must be a valid pointer to a valid VkAttachmentReference structure

- If `preserveAttachmentCount` is not `0`, `pPreserveAttachments` must be a valid pointer to an array of `preserveAttachmentCount` `uint32_t` values

Bits which can be set in VkSubpassDescription::`flags`, specifying usage of the subpass, are:

    typedef enum VkSubpassDescriptionFlagBits {
        VK_SUBPASS_DESCRIPTION_PER_VIEW_ATTRIBUTES_BIT_NVX = 0x00000001,
        VK_SUBPASS_DESCRIPTION_PER_VIEW_POSITION_X_ONLY_BIT_NVX = 0x00000002,
        VK_SUBPASS_DESCRIPTION_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkSubpassDescriptionFlagBits;

- `VK_SUBPASS_DESCRIPTION_PER_VIEW_ATTRIBUTES_BIT_NVX` specifies that shaders compiled for this subpass write the attributes for all views in a single invocation of each vertex processing stage. All pipelines compiled against a subpass that includes this bit must write per-view attributes to the `*PerViewNV[]` shader outputs, in addition to the non-per-view (e.g. `Position`) outputs.

- `VK_SUBPASS_DESCRIPTION_PER_VIEW_POSITION_X_ONLY_BIT_NVX` specifies that shaders compiled for this subpass use per-view positions which only differ in value in the x component. Per-view viewport mask can also be used.

    typedef VkFlags VkSubpassDescriptionFlags;

`VkSubpassDescriptionFlags` is a bitmask type for setting a mask of zero or more VkSubpassDescriptionFlagBits.

The `VkAttachmentReference` structure is defined as:

    typedef struct VkAttachmentReference {
        uint32_t         attachment;
        VkImageLayout    layout;
    } VkAttachmentReference;

- `attachment` is either an integer value identifying an attachment at the corresponding index in VkRenderPassCreateInfo::`pAttachments`, or `VK_ATTACHMENT_UNUSED` to signify that this attachment is not used.

- `layout` is a VkImageLayout value specifying the layout the attachment uses during the subpass.

Valid Usage

- If `attachment` is not `VK_ATTACHMENT_UNUSED`, `layout` must not be `VK_IMAGE_LAYOUT_UNDEFINED`, `VK_IMAGE_LAYOUT_PREINITIALIZED`, `VK_IMAGE_LAYOUT_PRESENT_SRC_KHR`, `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL_KHR`, `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL_KHR`, `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL_KHR`, or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL_KHR`

Valid Usage (Implicit)

- `layout` must be a valid VkImageLayout value

The `VkSubpassDependency` structure is defined as:

    typedef struct VkSubpassDependency {
        uint32_t                srcSubpass;
        uint32_t                dstSubpass;
        VkPipelineStageFlags    srcStageMask;
        VkPipelineStageFlags    dstStageMask;
        VkAccessFlags           srcAccessMask;
        VkAccessFlags           dstAccessMask;
        VkDependencyFlags       dependencyFlags;
    } VkSubpassDependency;

- `srcSubpass` is the subpass index of the first subpass in the dependency, or `VK_SUBPASS_EXTERNAL`.

- `dstSubpass` is the subpass index of the second subpass in the dependency, or `VK_SUBPASS_EXTERNAL`.

- `srcStageMask` is a bitmask of VkPipelineStageFlagBits specifying the source stage mask.

- `dstStageMask` is a bitmask of VkPipelineStageFlagBits specifying the destination stage mask

- `srcAccessMask` is a bitmask of VkAccessFlagBits specifying a source access mask.

- `dstAccessMask` is a bitmask of VkAccessFlagBits specifying a destination access mask.

- `dependencyFlags` is a bitmask of VkDependencyFlagBits.

If `srcSubpass` is equal to `dstSubpass` then the VkSubpassDependency describes a subpass self-dependency, and only constrains the pipeline barriers allowed within a subpass instance. Otherwise, when a render pass instance which includes a subpass dependency is submitted to a queue, it defines a memory dependency between the subpasses identified by `srcSubpass` and `dstSubpass`.

If `srcSubpass` is equal to `VK_SUBPASS_EXTERNAL`, the first synchronization scope includes commands that occur earlier in submission order than the vkCmdBeginRenderPass used to begin the render pass instance. Otherwise, the first set of commands includes all commands submitted as part of the subpass instance identified by `srcSubpass` and any load, store or multisample resolve operations on attachments used in `srcSubpass`. In either case, the first synchronization scope is limited to operations on the pipeline stages determined by the source stage mask specified by `srcStageMask`.

If `dstSubpass` is equal to `VK_SUBPASS_EXTERNAL`, the second synchronization scope includes commands that occur later in submission order than the vkCmdEndRenderPass used to end the render pass instance. Otherwise, the second set of commands includes all commands submitted as part of the subpass instance identified by `dstSubpass` and any load, store or multisample resolve operations on attachments used in `dstSubpass`. In either case, the second synchronization scope is limited to operations on the pipeline stages determined by the destination stage mask specified by `dstStageMask`.

The first access scope is limited to access in the pipeline stages determined by the source stage mask specified by `srcStageMask`. It is also limited to access types in the source access mask specified by `srcAccessMask`.

The second access scope is limited to access in the pipeline stages determined by the destination stage mask specified by `dstStageMask`. It is also limited to access types in the destination access mask specified by `dstAccessMask`.

The availability and visibility operations defined by a subpass dependency affect the execution of image layout transitions within the render pass.

| Note For non-attachment resources, the memory dependency expressed by subpass dependency is nearly identical to that of a VkMemoryBarrier (with matching `srcAccessMask` and `dstAccessMask` parameters) submitted as a part of a vkCmdPipelineBarrier (with matching `srcStageMask` and `dstStageMask` parameters). The only difference being that its scopes are limited to the identified subpasses rather than potentially affecting everything before and after. For attachments however, subpass dependencies work more like a VkImageMemoryBarrier defined similarly to the VkMemoryBarrier above, the queue family indices set to `VK_QUEUE_FAMILY_IGNORED`, and layouts as follows: The equivalent to `oldLayout` is the attachment’s layout according to the subpass description for `srcSubpass`. The equivalent to `newLayout` is the attachment’s layout according to the subpass description for `dstSubpass`.

Valid Usage

- If the geometry shaders feature is not enabled, `srcStageMask` must not contain `VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT`

- If the geometry shaders feature is not enabled, `dstStageMask` must not contain `VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT`

- If the tessellation shaders feature is not enabled, `srcStageMask` must not contain `VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT` or `VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT`

- If the tessellation shaders feature is not enabled, `dstStageMask` must not contain `VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT` or `VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT`

- `srcSubpass` must be less than or equal to `dstSubpass`, unless one of them is `VK_SUBPASS_EXTERNAL`, to avoid cyclic dependencies and ensure a valid execution order

- `srcSubpass` and `dstSubpass` must not both be equal to `VK_SUBPASS_EXTERNAL`

- If `srcSubpass` is equal to `dstSubpass` and not all of the stages in `srcStageMask` and `dstStageMask` are framebuffer-space stages, the logically latest pipeline stage in `srcStageMask` must be logically earlier than or equal to the logically earliest pipeline stage in `dstStageMask`

- Any access flag included in `srcAccessMask` must be supported by one of the pipeline stages in `srcStageMask`, as specified in the table of supported access types

- Any access flag included in `dstAccessMask` must be supported by one of the pipeline stages in `dstStageMask`, as specified in the table of supported access types

- If `srcSubpass` equals `dstSubpass`, and `srcStageMask` and `dstStageMask` both include a framebuffer-space stage, then `dependencyFlags` must include `VK_DEPENDENCY_BY_REGION_BIT`

- If `dependencyFlags` includes `VK_DEPENDENCY_VIEW_LOCAL_BIT`, `srcSubpass` must not be equal to `VK_SUBPASS_EXTERNAL`

- If `dependencyFlags` includes `VK_DEPENDENCY_VIEW_LOCAL_BIT`, `dstSubpass` must not be equal to `VK_SUBPASS_EXTERNAL`

- If `srcSubpass` equals `dstSubpass` and that subpass has more than one bit set in the view mask, then `dependencyFlags` must include `VK_DEPENDENCY_VIEW_LOCAL_BIT`

- If the mesh shaders feature is not enabled, `srcStageMask` must not contain `VK_PIPELINE_STAGE_MESH_SHADER_BIT_NV`

- If the task shaders feature is not enabled, `srcStageMask` must not contain `VK_PIPELINE_STAGE_TASK_SHADER_BIT_NV`

- If the mesh shaders feature is not enabled, `dstStageMask` must not contain `VK_PIPELINE_STAGE_MESH_SHADER_BIT_NV`

- If the task shaders feature is not enabled, `dstStageMask` must not contain `VK_PIPELINE_STAGE_TASK_SHADER_BIT_NV`

Valid Usage (Implicit)

- `srcStageMask` must be a valid combination of VkPipelineStageFlagBits values

- `srcStageMask` must not be `0`

- `dstStageMask` must be a valid combination of VkPipelineStageFlagBits values

- `dstStageMask` must not be `0`

- `srcAccessMask` must be a valid combination of VkAccessFlagBits values

- `dstAccessMask` must be a valid combination of VkAccessFlagBits values

- `dependencyFlags` must be a valid combination of VkDependencyFlagBits values

When multiview is enabled, the execution of the multiple views of one subpass may not occur simultaneously or even back-to-back, and rather may be interleaved with the execution of other subpasses. The load and store operations apply to attachments on a per-view basis. For example, an attachment using `VK_ATTACHMENT_LOAD_OP_CLEAR` will have each view cleared on first use, but the first use of one view may be temporally distant from the first use of another view.

| Note A good mental model for multiview is to think of a multiview subpass as if it were a collection of individual (per-view) subpasses that are logically grouped together and described as a single multiview subpass in the API. Similarly, a multiview attachment can be thought of like several individual attachments that happen to be layers in a single image. A view-local dependency between two multiview subpasses acts like a set of one-to-one dependencies between corresponding pairs of per-view subpasses. A view-global dependency between two multiview subpasses acts like a set of N × M dependencies between all pairs of per-view subpasses in the source and destination. Thus, it is a more compact representation which also makes clear the commonality and reuse that is present between views in a subpass. This interpretation motivates the answers to questions like “when does the load op apply” - it is on the first use of each view of an attachment, as if each view were a separate attachment.

If any two subpasses of a render pass activate transform feedback to the same bound transform feedback buffers, a subpass dependency must be included (either directly or via some intermediate subpasses) between them.

| editing-note The following two alleged implicit dependencies are practically no-ops, as the operations they describe are already guaranteed by semaphores and submission order (so they are almost entirely no-ops on their own). The only reason they exist is because it simplifies reasoning about where automatic layout transitions happen. Further rewrites of this chapter could potentially remove the need for these.

If there is no subpass dependency from `VK_SUBPASS_EXTERNAL` to the first subpass that uses an attachment, then an implicit subpass dependency exists from `VK_SUBPASS_EXTERNAL` to the first subpass it is used in. The implicit subpass dependency only exists if there exists an automatic layout transition away from `initialLayout`. The subpass dependency operates as if defined with the following parameters:

    VkSubpassDependency implicitDependency = {
        .srcSubpass = VK_SUBPASS_EXTERNAL;
        .dstSubpass = firstSubpass; // First subpass attachment is used in
        .srcStageMask = VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT;
        .dstStageMask = VK_PIPELINE_STAGE_ALL_COMMANDS_BIT;
        .srcAccessMask = 0;
        .dstAccessMask = VK_ACCESS_INPUT_ATTACHMENT_READ_BIT |
                         VK_ACCESS_COLOR_ATTACHMENT_READ_BIT |
                         VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT |
                         VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_READ_BIT |
                         VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT;
        .dependencyFlags = 0;
    };

Similarly, if there is no subpass dependency from the last subpass that uses an attachment to `VK_SUBPASS_EXTERNAL`, then an implicit subpass dependency exists from the last subpass it is used in to `VK_SUBPASS_EXTERNAL`. The implicit subpass dependency only exists if there exists an automatic layout transition into `finalLayout`. The subpass dependency operates as if defined with the following parameters:

    VkSubpassDependency implicitDependency = {
        .srcSubpass = lastSubpass; // Last subpass attachment is used in
        .dstSubpass = VK_SUBPASS_EXTERNAL;
        .srcStageMask = VK_PIPELINE_STAGE_ALL_COMMANDS_BIT;
        .dstStageMask = VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT;
        .srcAccessMask = VK_ACCESS_INPUT_ATTACHMENT_READ_BIT |
                         VK_ACCESS_COLOR_ATTACHMENT_READ_BIT |
                         VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT |
                         VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_READ_BIT |
                         VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT;
        .dstAccessMask = 0;
        .dependencyFlags = 0;
    };

As subpasses may overlap or execute out of order with regards to other subpasses unless a subpass dependency chain describes otherwise, the layout transitions required between subpasses cannot be known to an application. Instead, an application provides the layout that each attachment must be in at the start and end of a render pass, and the layout it must be in during each subpass it is used in. The implementation then must execute layout transitions between subpasses in order to guarantee that the images are in the layouts required by each subpass, and in the final layout at the end of the render pass.

Automatic layout transitions apply to the entire image subresource attached to the framebuffer. If the attachment view is a 2D or 2D array view of a 3D image, even if the attachment view only refers to a subset of the slices of the selected mip level of the 3D image, automatic layout transitions apply to the entire subresource referenced which is the entire mip level in this case.

Automatic layout transitions away from the layout used in a subpass happen-after the availability operations for all dependencies with that subpass as the `srcSubpass`.

Automatic layout transitions into the layout used in a subpass happen-before the visibility operations for all dependencies with that subpass as the `dstSubpass`.

Automatic layout transitions away from `initialLayout` happens-after the availability operations for all dependencies with a `srcSubpass` equal to `VK_SUBPASS_EXTERNAL`, where `dstSubpass` uses the attachment that will be transitioned. For attachments created with `VK_ATTACHMENT_DESCRIPTION_MAY_ALIAS_BIT`, automatic layout transitions away from `initialLayout` happen-after the availability operations for all dependencies with a `srcSubpass` equal to `VK_SUBPASS_EXTERNAL`, where `dstSubpass` uses any aliased attachment.

Automatic layout transitions into `finalLayout` happens-before the visibility operations for all dependencies with a `dstSubpass` equal to `VK_SUBPASS_EXTERNAL`, where `srcSubpass` uses the attachment that will be transitioned. For attachments created with `VK_ATTACHMENT_DESCRIPTION_MAY_ALIAS_BIT`, automatic layout transitions into `finalLayout` happen-before the visibility operations for all dependencies with a `dstSubpass` equal to `VK_SUBPASS_EXTERNAL`, where `srcSubpass` uses any aliased attachment.

The image layout of the depth aspect of a depth/stencil attachment referring to an image created with `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT` is dependent on the last sample locations used to render to the attachment, thus automatic layout transitions use the sample locations state specified in VkRenderPassSampleLocationsBeginInfoEXT.

Automatic layout transitions of an attachment referring to a depth/stencil image created with `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT` use the sample locations the image subresource range referenced by the attachment was last rendered with. If the current render pass does not use the attachment as a depth/stencil attachment in any subpass that happens-before, the automatic layout transition uses the sample locations state specified in the `sampleLocationsInfo` member of the element of the `VkRenderPassSampleLocationsBeginInfoEXT`::`pAttachmentInitialSampleLocations` array for which the `attachmentIndex` member equals the attachment index of the attachment, if one is specified. Otherwise, the automatic layout transition uses the sample locations state specified in the `sampleLocationsInfo` member of the element of the `VkRenderPassSampleLocationsBeginInfoEXT`::`pPostSubpassSampleLocations` array for which the `subpassIndex` member equals the index of the subpass that last used the attachment as a depth/stencil attachment, if one is specified.

If no sample locations state has been specified for an automatic layout transition performed on an attachment referring to a depth/stencil image created with `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT` the contents of the depth aspect of the depth/stencil attachment become undefined as if the layout of the attachment was transitioned from the `VK_IMAGE_LAYOUT_UNDEFINED` layout.

If two subpasses use the same attachment, and both subpasses use the attachment in a read-only layout, no subpass dependency needs to be specified between those subpasses. If an implementation treats those layouts separately, it must insert an implicit subpass dependency between those subpasses to separate the uses in each layout. The subpass dependency operates as if defined with the following parameters:

    // Used for input attachments
    VkPipelineStageFlags inputAttachmentStages = VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT;
    VkAccessFlags inputAttachmentAccess = VK_ACCESS_INPUT_ATTACHMENT_READ_BIT;

    // Used for depth/stencil attachments
    VkPipelineStageFlags depthStencilAttachmentStages = VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT | VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT;
    VkAccessFlags depthStencilAttachmentAccess = VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_READ_BIT;

    VkSubpassDependency implicitDependency = {
        .srcSubpass = firstSubpass;
        .dstSubpass = secondSubpass;
        .srcStageMask = inputAttachmentStages | depthStencilAttachmentStages;
        .dstStageMask = inputAttachmentStages | depthStencilAttachmentStages;
        .srcAccessMask = inputAttachmentAccess | depthStencilAttachmentAccess;
        .dstAccessMask = inputAttachmentAccess | depthStencilAttachmentAccess;
        .dependencyFlags = 0;
    };

If a subpass uses the same attachment as both an input attachment and either a color attachment or a depth/stencil attachment, writes via the color or depth/stencil attachment are not automatically made visible to reads via the input attachment, causing a feedback loop, except in any of the following conditions:

- If the color components or depth/stencil components read by the input attachment are mutually exclusive with the components written by the color or depth/stencil attachments, then there is no feedback loop. This requires the graphics pipelines used by the subpass to disable writes to color components that are read as inputs via the `colorWriteMask`, and to disable writes to depth/stencil components that are read as inputs via `depthWriteEnable` or `stencilTestEnable`.

- If the attachment is used as an input attachment and depth/stencil attachment only, and the depth/stencil attachment is not written to.

- If a memory dependency is inserted between when the attachment is written and when it is subsequently read by later fragments. Pipeline barriers expressing a subpass self-dependency are the only way to achieve this, and one must be inserted every time a fragment will read values at a particular sample (x, y, layer, sample) coordinate, if those values have been written since the most recent pipeline barrier; or the since start of the subpass if there have been no pipeline barriers since the start of the subpass.

An attachment used as both an input attachment and a color attachment must be in the `VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR` or `VK_IMAGE_LAYOUT_GENERAL` layout. An attachment used as an input attachment and depth/stencil attachment must be in the `VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR`, `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL`, or `VK_IMAGE_LAYOUT_GENERAL` layout. An attachment must not be used as both a depth/stencil attachment and a color attachment.

A more extensible version of render pass creation is also defined below.

To create a render pass, call:

    VkResult vkCreateRenderPass2(
        VkDevice                                    device,
        const VkRenderPassCreateInfo2*              pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkRenderPass*                               pRenderPass);

or the equivalent command

    VkResult vkCreateRenderPass2KHR(
        VkDevice                                    device,
        const VkRenderPassCreateInfo2*              pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkRenderPass*                               pRenderPass);

- `device` is the logical device that creates the render pass.

- `pCreateInfo` is a pointer to a VkRenderPassCreateInfo2 structure describing the parameters of the render pass.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pRenderPass` is a pointer to a VkRenderPass handle in which the resulting render pass object is returned.

This command is functionally identical to vkCreateRenderPass, but includes extensible sub-structures that include `sType` and `pNext` parameters, allowing them to be more easily extended.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkRenderPassCreateInfo2 structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pRenderPass` must be a valid pointer to a VkRenderPass handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkRenderPassCreateInfo2` structure is defined as:

    typedef struct VkRenderPassCreateInfo2 {
        VkStructureType                    sType;
        const void*                        pNext;
        VkRenderPassCreateFlags            flags;
        uint32_t                           attachmentCount;
        const VkAttachmentDescription2*    pAttachments;
        uint32_t                           subpassCount;
        const VkSubpassDescription2*       pSubpasses;
        uint32_t                           dependencyCount;
        const VkSubpassDependency2*        pDependencies;
        uint32_t                           correlatedViewMaskCount;
        const uint32_t*                    pCorrelatedViewMasks;
    } VkRenderPassCreateInfo2;

or the equivalent

    typedef VkRenderPassCreateInfo2 VkRenderPassCreateInfo2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `attachmentCount` is the number of attachments used by this render pass.

- `pAttachments` is a pointer to an array of `attachmentCount` VkAttachmentDescription2 structures describing the attachments used by the render pass.

- `subpassCount` is the number of subpasses to create.

- `pSubpasses` is a pointer to an array of `subpassCount` VkSubpassDescription2 structures describing each subpass.

- `dependencyCount` is the number of dependencies between pairs of subpasses.

- `pDependencies` is a pointer to an array of `dependencyCount` VkSubpassDependency structures describing dependencies between pairs of subpasses.

- `correlatedViewMaskCount` is the number of correlation masks.

- `pCorrelatedViewMasks` is a pointer to an array of view masks indicating sets of views that may be more efficient to render concurrently.

Parameters defined by this structure with the same name as those in VkRenderPassCreateInfo have the identical effect to those parameters; the child structures are variants of those used in VkRenderPassCreateInfo which add `sType` and `pNext` parameters, allowing them to be extended.

If the VkSubpassDescription2::`viewMask` member of any element of `pSubpasses` is not zero, multiview functionality is considered to be enabled for this render pass.

`correlatedViewMaskCount` and `pCorrelatedViewMasks` have the same effect as VkRenderPassMultiviewCreateInfo::`correlationMaskCount` and VkRenderPassMultiviewCreateInfo::`pCorrelationMasks`, respectively.

Valid Usage

- If any two subpasses operate on attachments with overlapping ranges of the same `VkDeviceMemory` object, and at least one subpass writes to that area of `VkDeviceMemory`, a subpass dependency must be included (either directly or via some intermediate subpasses) between them

- If the `attachment` member of any element of `pInputAttachments`, `pColorAttachments`, `pResolveAttachments` or `pDepthStencilAttachment`, or the attachment indexed by any element of `pPreserveAttachments` in any given element of `pSubpasses` is bound to a range of a `VkDeviceMemory` object that overlaps with any other attachment in any subpass (including the same subpass), the `VkAttachmentDescription2` structures describing them must include `VK_ATTACHMENT_DESCRIPTION_MAY_ALIAS_BIT` in `flags`

- If the `attachment` member of any element of `pInputAttachments`, `pColorAttachments`, `pResolveAttachments` or `pDepthStencilAttachment`, or any element of `pPreserveAttachments` in any given element of `pSubpasses` is not `VK_ATTACHMENT_UNUSED`, it must be less than `attachmentCount`

- For any member of `pAttachments` with a `loadOp` equal to `VK_ATTACHMENT_LOAD_OP_CLEAR`, the first use of that attachment must not specify a `layout` equal to `VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL`, or `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL`

- For any member of `pAttachments` with a `stencilLoadOp` equal to `VK_ATTACHMENT_LOAD_OP_CLEAR`, the first use of that attachment must not specify a `layout` equal to `VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL`, or `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL`.

- For any element of `pDependencies`, if the `srcSubpass` is not `VK_SUBPASS_EXTERNAL`, all stage flags included in the `srcStageMask` member of that dependency must be a pipeline stage supported by the pipeline identified by the `pipelineBindPoint` member of the source subpass

- For any element of `pDependencies`, if the `dstSubpass` is not `VK_SUBPASS_EXTERNAL`, all stage flags included in the `dstStageMask` member of that dependency must be a pipeline stage supported by the pipeline identified by the `pipelineBindPoint` member of the destination subpass

- The set of bits included in any element of `pCorrelatedViewMasks` must not overlap with the set of bits included in any other element of `pCorrelatedViewMasks`

- If the VkSubpassDescription2::`viewMask` member of all elements of `pSubpasses` is `0`, `correlatedViewMaskCount` must be `0`

- The VkSubpassDescription2::`viewMask` member of all elements of `pSubpasses` must either all be `0`, or all not be `0`

- If the VkSubpassDescription2::`viewMask` member of all elements of `pSubpasses` is `0`, the `dependencyFlags` member of any element of `pDependencies` must not include `VK_DEPENDENCY_VIEW_LOCAL_BIT`

- For any element of `pDependencies` where its `srcSubpass` member equals its `dstSubpass` member, if the `viewMask` member of the corresponding element of `pSubpasses` includes more than one bit, its `dependencyFlags` member must include `VK_DEPENDENCY_VIEW_LOCAL_BIT`

- The `viewMask` member must not have a bit set at an index greater than or equal to VkPhysicalDeviceLimits::`maxFramebufferLayers`

- If the `attachment` member of any element of the `pInputAttachments` member of any element of `pSubpasses` is not `VK_ATTACHMENT_UNUSED`, the `aspectMask` member of that element of `pInputAttachments` must only include aspects that are present in images of the format specified by the element of `pAttachments` specified by `attachment`

- The `srcSubpass` member of each element of `pDependencies` must be less than `subpassCount`

- The `dstSubpass` member of each element of `pDependencies` must be less than `subpassCount`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO_2`

- `pNext` must be `NULL` or a pointer to a valid instance of VkRenderPassFragmentDensityMapCreateInfoEXT

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be a valid combination of VkRenderPassCreateFlagBits values

- If `attachmentCount` is not `0`, `pAttachments` must be a valid pointer to an array of `attachmentCount` valid VkAttachmentDescription2 structures

- `pSubpasses` must be a valid pointer to an array of `subpassCount` valid VkSubpassDescription2 structures

- If `dependencyCount` is not `0`, `pDependencies` must be a valid pointer to an array of `dependencyCount` valid VkSubpassDependency2 structures

- If `correlatedViewMaskCount` is not `0`, `pCorrelatedViewMasks` must be a valid pointer to an array of `correlatedViewMaskCount` `uint32_t` values

- `subpassCount` must be greater than `0`

The `VkAttachmentDescription2` structure is defined as:

    typedef struct VkAttachmentDescription2 {
        VkStructureType                 sType;
        const void*                     pNext;
        VkAttachmentDescriptionFlags    flags;
        VkFormat                        format;
        VkSampleCountFlagBits           samples;
        VkAttachmentLoadOp              loadOp;
        VkAttachmentStoreOp             storeOp;
        VkAttachmentLoadOp              stencilLoadOp;
        VkAttachmentStoreOp             stencilStoreOp;
        VkImageLayout                   initialLayout;
        VkImageLayout                   finalLayout;
    } VkAttachmentDescription2;

or the equivalent

    typedef VkAttachmentDescription2 VkAttachmentDescription2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkAttachmentDescriptionFlagBits specifying additional properties of the attachment.

- `format` is a VkFormat value specifying the format of the image that will be used for the attachment.

- `samples` is the number of samples of the image as defined in VkSampleCountFlagBits.

- `loadOp` is a VkAttachmentLoadOp value specifying how the contents of color and depth components of the attachment are treated at the beginning of the subpass where it is first used.

- `storeOp` is a VkAttachmentStoreOp value specifying how the contents of color and depth components of the attachment are treated at the end of the subpass where it is last used.

- `stencilLoadOp` is a VkAttachmentLoadOp value specifying how the contents of stencil components of the attachment are treated at the beginning of the subpass where it is first used.

- `stencilStoreOp` is a VkAttachmentStoreOp value specifying how the contents of stencil components of the attachment are treated at the end of the last subpass where it is used.

- `initialLayout` is the layout the attachment image subresource will be in when a render pass instance begins.

- `finalLayout` is the layout the attachment image subresource will be transitioned to when a render pass instance ends.

Parameters defined by this structure with the same name as those in VkAttachmentDescription have the identical effect to those parameters.

If the `separateDepthStencilLayouts` feature is enabled, and `format` is a depth/stencil format, `initialLayout` and `finalLayout` can be set to a layout that only specifies the layout of the depth aspect.

If `format` is a depth/stencil format, and `initialLayout` only specifies the initial layout of the depth aspect of the attachment, the initial layout of the stencil aspect is specified by the `stencilInitialLayout` member of a VkAttachmentDescriptionStencilLayout structure included in the `pNext` chain. Otherwise, `initialLayout` describes the initial layout for all relevant image aspects.

If `format` is a depth/stencil format, and `finalLayout` only specifies the final layout of the depth aspect of the attachment, the final layout of the stencil aspect is specified by the `stencilFinalLayout` member of a VkAttachmentDescriptionStencilLayout structure included in the `pNext` chain. Otherwise, `finalLayout` describes the final layout for all relevant image aspects.

Valid Usage

- `finalLayout` must not be `VK_IMAGE_LAYOUT_UNDEFINED` or `VK_IMAGE_LAYOUT_PREINITIALIZED`

- If `format` is a color format, `initialLayout` must not be `VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL`, or `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL`

- If `format` is a depth/stencil format, `initialLayout` must not be `VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL`

- If `format` is a color format, `finalLayout` must not be `VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL`, or `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL`

- If `format` is a depth/stencil format, `finalLayout` must not be `VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL`

- If the `separateDepthStencilLayouts` feature is not enabled, `initialLayout` must not be `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL` or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL`

- If the `separateDepthStencilLayouts` feature is not enabled, `finalLayout` must not be `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL` or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL`

- If `format` is a color format, `initialLayout` must not be `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL` or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL`

- If `format` is a color format, `finalLayout` must not be `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL` or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL`

- If `format` is a depth/stencil format which includes both depth and stencil aspects, and `initialLayout` is `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL` or `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`, the `pNext` chain must include a VkAttachmentDescriptionStencilLayout structure

- If `format` is a depth/stencil format which includes both depth and stencil aspects, and `finalLayout` is `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL` or `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`, the `pNext` chain must include a VkAttachmentDescriptionStencilLayout structure

- If `format` is a depth/stencil format which includes only the depth aspect, `initialLayout` must not be `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL` or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL`

- If `format` is a depth/stencil format which includes only the depth aspect, `finalLayout` must not be `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL` or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL`

- If `format` is a depth/stencil format which includes only the stencil aspect, `initialLayout` must not be `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL` or `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`

- If `format` is a depth/stencil format which includes only the stencil aspect, `finalLayout` must not be `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL` or `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_ATTACHMENT_DESCRIPTION_2`

- `flags` must be a valid combination of VkAttachmentDescriptionFlagBits values

- `format` must be a valid VkFormat value

- `samples` must be a valid VkSampleCountFlagBits value

- `loadOp` must be a valid VkAttachmentLoadOp value

- `storeOp` must be a valid VkAttachmentStoreOp value

- `stencilLoadOp` must be a valid VkAttachmentLoadOp value

- `stencilStoreOp` must be a valid VkAttachmentStoreOp value

- `initialLayout` must be a valid VkImageLayout value

- `finalLayout` must be a valid VkImageLayout value

The `VkAttachmentDescriptionStencilLayout` structure is defined as:

    typedef struct VkAttachmentDescriptionStencilLayout {
        VkStructureType    sType;
        void*              pNext;
        VkImageLayout      stencilInitialLayout;
        VkImageLayout      stencilFinalLayout;
    } VkAttachmentDescriptionStencilLayout;

or the equivalent

    typedef VkAttachmentDescriptionStencilLayout VkAttachmentDescriptionStencilLayoutKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `stencilInitialLayout` is the layout the stencil aspect of the attachment image subresource will be in when a render pass instance begins.

- `stencilFinalLayout` is the layout the stencil aspect of the attachment image subresource will be transitioned to when a render pass instance ends.

Valid Usage

- `stencilInitialLayout` must not be `VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL`, or `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL`

- `stencilFinalLayout` must not be `VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL`, or `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL`

- `stencilFinalLayout` must not be `VK_IMAGE_LAYOUT_UNDEFINED` or `VK_IMAGE_LAYOUT_PREINITIALIZED`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_ATTACHMENT_DESCRIPTION_STENCIL_LAYOUT`

- `stencilInitialLayout` must be a valid VkImageLayout value

- `stencilFinalLayout` must be a valid VkImageLayout value

The `VkSubpassDescription2` structure is defined as:

    typedef struct VkSubpassDescription2 {
        VkStructureType                  sType;
        const void*                      pNext;
        VkSubpassDescriptionFlags        flags;
        VkPipelineBindPoint              pipelineBindPoint;
        uint32_t                         viewMask;
        uint32_t                         inputAttachmentCount;
        const VkAttachmentReference2*    pInputAttachments;
        uint32_t                         colorAttachmentCount;
        const VkAttachmentReference2*    pColorAttachments;
        const VkAttachmentReference2*    pResolveAttachments;
        const VkAttachmentReference2*    pDepthStencilAttachment;
        uint32_t                         preserveAttachmentCount;
        const uint32_t*                  pPreserveAttachments;
    } VkSubpassDescription2;

or the equivalent

    typedef VkSubpassDescription2 VkSubpassDescription2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkSubpassDescriptionFlagBits specifying usage of the subpass.

- `pipelineBindPoint` is a VkPipelineBindPoint value specifying the pipeline type supported for this subpass.

- `viewMask` is a bitfield of view indices describing which views rendering is broadcast to in this subpass, when multiview is enabled.

- `inputAttachmentCount` is the number of input attachments.

- `pInputAttachments` is a pointer to an array of VkAttachmentReference2 structures defining the input attachments for this subpass and their layouts.

- `colorAttachmentCount` is the number of color attachments.

- `pColorAttachments` is a pointer to an array of VkAttachmentReference2 structures defining the color attachments for this subpass and their layouts.

- `pResolveAttachments` is an optional array of `colorAttachmentCount` VkAttachmentReference2 structures defining the resolve attachments for this subpass and their layouts.

- `pDepthStencilAttachment` is a pointer to a VkAttachmentReference2 structure specifying the depth/stencil attachment for this subpass and its layout.

- `preserveAttachmentCount` is the number of preserved attachments.

- `pPreserveAttachments` is a pointer to an array of `preserveAttachmentCount` render pass attachment indices identifying attachments that are not used by this subpass, but whose contents must be preserved throughout the subpass.

Parameters defined by this structure with the same name as those in VkSubpassDescription have the identical effect to those parameters.

`viewMask` has the same effect for the described subpass as VkRenderPassMultiviewCreateInfo::`pViewMasks` has on each corresponding subpass.

Valid Usage

- `pipelineBindPoint` must be `VK_PIPELINE_BIND_POINT_GRAPHICS`

- `colorAttachmentCount` must be less than or equal to `VkPhysicalDeviceLimits`::`maxColorAttachments`

- If the first use of an attachment in this render pass is as an input attachment, and the attachment is not also used as a color or depth/stencil attachment in the same subpass, then `loadOp` must not be `VK_ATTACHMENT_LOAD_OP_CLEAR`

- If `pResolveAttachments` is not `NULL`, for each resolve attachment that does not have the value `VK_ATTACHMENT_UNUSED`, the corresponding color attachment must not have the value `VK_ATTACHMENT_UNUSED`

- If `pResolveAttachments` is not `NULL`, for each resolve attachment that is not `VK_ATTACHMENT_UNUSED`, the corresponding color attachment must not have a sample count of `VK_SAMPLE_COUNT_1_BIT`

- If `pResolveAttachments` is not `NULL`, each resolve attachment that is not `VK_ATTACHMENT_UNUSED` must have a sample count of `VK_SAMPLE_COUNT_1_BIT`

- Any given element of `pResolveAttachments` must have the same VkFormat as its corresponding color attachment

- All attachments in `pColorAttachments` that are not `VK_ATTACHMENT_UNUSED` must have the same sample count

- All attachments in `pInputAttachments` that are not `VK_ATTACHMENT_UNUSED` must have formats whose features contain at least one of `VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT` or `VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT`.

- All attachments in `pColorAttachments` that are not `VK_ATTACHMENT_UNUSED` must have formats whose features contain `VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT`

- All attachments in `pResolveAttachments` that are not `VK_ATTACHMENT_UNUSED` must have formats whose features contain `VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT`

- If `pDepthStencilAttachment` is not `NULL` and the attachment is not `VK_ATTACHMENT_UNUSED` then it must have a format whose features contain `VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT`

- If the `VK_AMD_mixed_attachment_samples` extension is enabled, all attachments in `pColorAttachments` that are not `VK_ATTACHMENT_UNUSED` must have a sample count that is smaller than or equal to the sample count of `pDepthStencilAttachment` if it is not `VK_ATTACHMENT_UNUSED`

- If neither the `VK_AMD_mixed_attachment_samples` nor the `VK_NV_framebuffer_mixed_samples` extensions are enabled, and if `pDepthStencilAttachment` is not `VK_ATTACHMENT_UNUSED` and any attachments in `pColorAttachments` are not `VK_ATTACHMENT_UNUSED`, they must have the same sample count

- The `attachment` member of any element of `pPreserveAttachments` must not be `VK_ATTACHMENT_UNUSED`

- Any given element of `pPreserveAttachments` must not also be an element of any other member of the subpass description

- If any attachment is used by more than one VkAttachmentReference member, then each use must use the same `layout`

- If `flags` includes `VK_SUBPASS_DESCRIPTION_PER_VIEW_POSITION_X_ONLY_BIT_NVX`, it must also include `VK_SUBPASS_DESCRIPTION_PER_VIEW_ATTRIBUTES_BIT_NVX`.

- If the `attachment` member of any element of `pInputAttachments` is not `VK_ATTACHMENT_UNUSED`, then the `aspectMask` member must be a valid combination of VkImageAspectFlagBits

- If the `attachment` member of any element of `pInputAttachments` is not `VK_ATTACHMENT_UNUSED`, then the `aspectMask` member must not be `0`

- If the `attachment` member of any element of `pInputAttachments` is not `VK_ATTACHMENT_UNUSED`, then the `aspectMask` member must not include `VK_IMAGE_ASPECT_METADATA_BIT`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SUBPASS_DESCRIPTION_2`

- `flags` must be a valid combination of VkSubpassDescriptionFlagBits values

- `pipelineBindPoint` must be a valid VkPipelineBindPoint value

- If `inputAttachmentCount` is not `0`, `pInputAttachments` must be a valid pointer to an array of `inputAttachmentCount` valid VkAttachmentReference2 structures

- If `colorAttachmentCount` is not `0`, `pColorAttachments` must be a valid pointer to an array of `colorAttachmentCount` valid VkAttachmentReference2 structures

- If `colorAttachmentCount` is not `0`, and `pResolveAttachments` is not `NULL`, `pResolveAttachments` must be a valid pointer to an array of `colorAttachmentCount` valid VkAttachmentReference2 structures

- If `pDepthStencilAttachment` is not `NULL`, `pDepthStencilAttachment` must be a valid pointer to a valid VkAttachmentReference2 structure

- If `preserveAttachmentCount` is not `0`, `pPreserveAttachments` must be a valid pointer to an array of `preserveAttachmentCount` `uint32_t` values

If the `pNext` list of `VkSubpassDescription2` includes a `VkSubpassDescriptionDepthStencilResolve` structure, then that structure describes multisample resolve operations for the depth/stencil attachment in a subpass.

The `VkSubpassDescriptionDepthStencilResolve` structure is defined as:

    typedef struct VkSubpassDescriptionDepthStencilResolve {
        VkStructureType                  sType;
        const void*                      pNext;
        VkResolveModeFlagBits            depthResolveMode;
        VkResolveModeFlagBits            stencilResolveMode;
        const VkAttachmentReference2*    pDepthStencilResolveAttachment;
    } VkSubpassDescriptionDepthStencilResolve;

or the equivalent

    typedef VkSubpassDescriptionDepthStencilResolve VkSubpassDescriptionDepthStencilResolveKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `depthResolveMode` is a bitmask of VkResolveModeFlagBits describing the depth resolve mode.

- `stencilResolveMode` is a bitmask of VkResolveModeFlagBits describing the stencil resolve mode.

- `pDepthStencilResolveAttachment` is an optional VkAttachmentReference structure defining the depth/stencil resolve attachment for this subpass and its layout.

Valid Usage

- If `pDepthStencilResolveAttachment` is not `NULL` and does not have the value `VK_ATTACHMENT_UNUSED`, `pDepthStencilAttachment` must not have the value `VK_ATTACHMENT_UNUSED`

- If `pDepthStencilResolveAttachment` is not `NULL` and does not have the value `VK_ATTACHMENT_UNUSED`, `depthResolveMode` and `stencilResolveMode` must not both be `VK_RESOLVE_MODE_NONE`

- If `pDepthStencilResolveAttachment` is not `NULL` and does not have the value `VK_ATTACHMENT_UNUSED`, `pDepthStencilAttachment` must not have a sample count of `VK_SAMPLE_COUNT_1_BIT`

- If `pDepthStencilResolveAttachment` is not `NULL` and does not have the value `VK_ATTACHMENT_UNUSED`, `pDepthStencilResolveAttachment` must have a sample count of `VK_SAMPLE_COUNT_1_BIT`

- If `pDepthStencilResolveAttachment` is not `NULL` and does not have the value `VK_ATTACHMENT_UNUSED` then it must have a format whose features contain `VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT`

- If the VkFormat of `pDepthStencilResolveAttachment` has a depth component, then the VkFormat of `pDepthStencilAttachment` must have a depth component with the same number of bits and numerical type

- If the VkFormat of `pDepthStencilResolveAttachment` has a stencil component, then the VkFormat of `pDepthStencilAttachment` must have a stencil component with the same number of bits and numerical type

- The value of `depthResolveMode` must be one of the bits set in VkPhysicalDeviceDepthStencilResolveProperties::`supportedDepthResolveModes` or `VK_RESOLVE_MODE_NONE`

- The value of `stencilResolveMode` must be one of the bits set in VkPhysicalDeviceDepthStencilResolveProperties::`supportedStencilResolveModes` or `VK_RESOLVE_MODE_NONE`

- If the VkFormat of `pDepthStencilResolveAttachment` has both depth and stencil components, VkPhysicalDeviceDepthStencilResolveProperties::`independentResolve` is `VK_FALSE`, and VkPhysicalDeviceDepthStencilResolveProperties::`independentResolveNone` is `VK_FALSE`, then the values of `depthResolveMode` and `stencilResolveMode` must be identical

- If the VkFormat of `pDepthStencilResolveAttachment` has both depth and stencil components, VkPhysicalDeviceDepthStencilResolveProperties::`independentResolve` is `VK_FALSE` and VkPhysicalDeviceDepthStencilResolveProperties::`independentResolveNone` is `VK_TRUE`, then the values of `depthResolveMode` and `stencilResolveMode` must be identical or one of them must be `VK_RESOLVE_MODE_NONE`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SUBPASS_DESCRIPTION_DEPTH_STENCIL_RESOLVE`

- `depthResolveMode` must be a valid VkResolveModeFlagBits value

- `stencilResolveMode` must be a valid VkResolveModeFlagBits value

- If `pDepthStencilResolveAttachment` is not `NULL`, `pDepthStencilResolveAttachment` must be a valid pointer to a valid VkAttachmentReference2 structure

Possible values of VkSubpassDescriptionDepthStencilResolve::`depthResolveMode` and `stencilResolveMode`, specifying the depth and stencil resolve modes, are:

    typedef enum VkResolveModeFlagBits {
        VK_RESOLVE_MODE_NONE = 0,
        VK_RESOLVE_MODE_SAMPLE_ZERO_BIT = 0x00000001,
        VK_RESOLVE_MODE_AVERAGE_BIT = 0x00000002,
        VK_RESOLVE_MODE_MIN_BIT = 0x00000004,
        VK_RESOLVE_MODE_MAX_BIT = 0x00000008,
        VK_RESOLVE_MODE_NONE_KHR = VK_RESOLVE_MODE_NONE,
        VK_RESOLVE_MODE_SAMPLE_ZERO_BIT_KHR = VK_RESOLVE_MODE_SAMPLE_ZERO_BIT,
        VK_RESOLVE_MODE_AVERAGE_BIT_KHR = VK_RESOLVE_MODE_AVERAGE_BIT,
        VK_RESOLVE_MODE_MIN_BIT_KHR = VK_RESOLVE_MODE_MIN_BIT,
        VK_RESOLVE_MODE_MAX_BIT_KHR = VK_RESOLVE_MODE_MAX_BIT,
        VK_RESOLVE_MODE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkResolveModeFlagBits;

or the equivalent

    typedef VkResolveModeFlagBits VkResolveModeFlagBitsKHR;

- `VK_RESOLVE_MODE_NONE` indicates that no resolve operation is done.

- `VK_RESOLVE_MODE_SAMPLE_ZERO_BIT` indicates that result of the resolve operation is equal to the value of sample 0.

- `VK_RESOLVE_MODE_AVERAGE_BIT` indicates that result of the resolve operation is the average of the sample values.

- `VK_RESOLVE_MODE_MIN_BIT` indicates that result of the resolve operation is the minimum of the sample values.

- `VK_RESOLVE_MODE_MAX_BIT` indicates that result of the resolve operation is the maximum of the sample values.

    typedef VkFlags VkResolveModeFlags;

or the equivalent

    typedef VkResolveModeFlags VkResolveModeFlagsKHR;

`VkResolveModeFlags` is a bitmask type for setting a mask of zero or more VkResolveModeFlagBits.

The `VkAttachmentReference2` structure is defined as:

    typedef struct VkAttachmentReference2 {
        VkStructureType       sType;
        const void*           pNext;
        uint32_t              attachment;
        VkImageLayout         layout;
        VkImageAspectFlags    aspectMask;
    } VkAttachmentReference2;

or the equivalent

    typedef VkAttachmentReference2 VkAttachmentReference2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `attachment` is either an integer value identifying an attachment at the corresponding index in VkRenderPassCreateInfo::`pAttachments`, or `VK_ATTACHMENT_UNUSED` to signify that this attachment is not used.

- `layout` is a VkImageLayout value specifying the layout the attachment uses during the subpass.

- `aspectMask` is a mask of which aspect(s) can be accessed within the specified subpass as an input attachment.

Parameters defined by this structure with the same name as those in VkAttachmentReference have the identical effect to those parameters.

`aspectMask` has the same effect for the described attachment as VkInputAttachmentAspectReference::`aspectMask` has on each corresponding attachment. It is ignored when this structure is used to describe anything other than an input attachment reference.

If the `separateDepthStencilLayouts` feature is enabled, and `attachment` has a depth/stencil format, `layout` can be set to a layout that only specifies the layout of the depth aspect.

If `layout` only specifies the layout of the depth aspect of the attachment, the layout of the stencil aspect is specified by the `stencilLayout` member of a VkAttachmentReferenceStencilLayout structure included in the `pNext` chain. Otherwise, `layout` describes the layout for all relevant image aspects.

Valid Usage

- If `attachment` is not `VK_ATTACHMENT_UNUSED`, `layout` must not be `VK_IMAGE_LAYOUT_UNDEFINED`, `VK_IMAGE_LAYOUT_PREINITIALIZED`, or `VK_IMAGE_LAYOUT_PRESENT_SRC_KHR`

- If `attachment` is not `VK_ATTACHMENT_UNUSED`, and `aspectMask` does not include `VK_IMAGE_ASPECT_STENCIL_BIT` or `VK_IMAGE_ASPECT_DEPTH_BIT`, `layout` must not be `VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL`, or `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL`

- If `attachment` is not `VK_ATTACHMENT_UNUSED`, and `aspectMask` does not include `VK_IMAGE_ASPECT_COLOR_BIT`, `layout` must not be `VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL`

- If the `separateDepthStencilLayouts` feature is not enabled, and `attachment` is not `VK_ATTACHMENT_UNUSED`, `layout` must not be `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL`, or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL`,

- If `attachment` is not `VK_ATTACHMENT_UNUSED`, and `aspectMask` includes `VK_IMAGE_ASPECT_COLOR_BIT`, `layout` must not be `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL`, or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL`,

- If `attachment` is not `VK_ATTACHMENT_UNUSED`, and `aspectMask` includes both `VK_IMAGE_ASPECT_DEPTH_BIT` and `VK_IMAGE_ASPECT_STENCIL_BIT`, and `layout` is `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL` or `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`, the `pNext` chain must include a VkAttachmentReferenceStencilLayout structure

- If `attachment` is not `VK_ATTACHMENT_UNUSED`, and `aspectMask` includes only `VK_IMAGE_ASPECT_DEPTH_BIT` then `layout` must not be `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL`, or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL`

- If `attachment` is not `VK_ATTACHMENT_UNUSED`, and `aspectMask` includes only `VK_IMAGE_ASPECT_STENCIL_BIT` then `layout` must not be `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL`, or `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_ATTACHMENT_REFERENCE_2`

- `layout` must be a valid VkImageLayout value

The `VkAttachmentReferenceStencilLayout` structure is defined as:

    typedef struct VkAttachmentReferenceStencilLayout {
        VkStructureType    sType;
        void*              pNext;
        VkImageLayout      stencilLayout;
    } VkAttachmentReferenceStencilLayout;

or the equivalent

    typedef VkAttachmentReferenceStencilLayout VkAttachmentReferenceStencilLayoutKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `stencilLayout` is a VkImageLayout value specifying the layout the stencil aspect of the attachment uses during the subpass.

Valid Usage

- `stencilLayout` must not be `VK_IMAGE_LAYOUT_UNDEFINED`, `VK_IMAGE_LAYOUT_PREINITIALIZED`, `VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL`, or `VK_IMAGE_LAYOUT_PRESENT_SRC_KHR`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_ATTACHMENT_REFERENCE_STENCIL_LAYOUT`

- `stencilLayout` must be a valid VkImageLayout value

The `VkSubpassDependency2` structure is defined as:

    typedef struct VkSubpassDependency2 {
        VkStructureType         sType;
        const void*             pNext;
        uint32_t                srcSubpass;
        uint32_t                dstSubpass;
        VkPipelineStageFlags    srcStageMask;
        VkPipelineStageFlags    dstStageMask;
        VkAccessFlags           srcAccessMask;
        VkAccessFlags           dstAccessMask;
        VkDependencyFlags       dependencyFlags;
        int32_t                 viewOffset;
    } VkSubpassDependency2;

or the equivalent

    typedef VkSubpassDependency2 VkSubpassDependency2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `srcSubpass` is the subpass index of the first subpass in the dependency, or `VK_SUBPASS_EXTERNAL`.

- `dstSubpass` is the subpass index of the second subpass in the dependency, or `VK_SUBPASS_EXTERNAL`.

- `srcStageMask` is a bitmask of VkPipelineStageFlagBits specifying the source stage mask.

- `dstStageMask` is a bitmask of VkPipelineStageFlagBits specifying the destination stage mask

- `srcAccessMask` is a bitmask of VkAccessFlagBits specifying a source access mask.

- `dstAccessMask` is a bitmask of VkAccessFlagBits specifying a destination access mask.

- `dependencyFlags` is a bitmask of VkDependencyFlagBits.

- `viewOffset` controls which views in the source subpass the views in the destination subpass depend on.

Parameters defined by this structure with the same name as those in VkSubpassDependency have the identical effect to those parameters.

`viewOffset` has the same effect for the described subpass dependency as VkRenderPassMultiviewCreateInfo::`pViewOffsets` has on each corresponding subpass dependency.

Valid Usage

- If the geometry shaders feature is not enabled, `srcStageMask` must not contain `VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT`

- If the geometry shaders feature is not enabled, `dstStageMask` must not contain `VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT`

- If the tessellation shaders feature is not enabled, `srcStageMask` must not contain `VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT` or `VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT`

- If the tessellation shaders feature is not enabled, `dstStageMask` must not contain `VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT` or `VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT`

- `srcSubpass` must be less than or equal to `dstSubpass`, unless one of them is `VK_SUBPASS_EXTERNAL`, to avoid cyclic dependencies and ensure a valid execution order

- `srcSubpass` and `dstSubpass` must not both be equal to `VK_SUBPASS_EXTERNAL`

- If `srcSubpass` is equal to `dstSubpass` and not all of the stages in `srcStageMask` and `dstStageMask` are framebuffer-space stages, the logically latest pipeline stage in `srcStageMask` must be logically earlier than or equal to the logically earliest pipeline stage in `dstStageMask`

- Any access flag included in `srcAccessMask` must be supported by one of the pipeline stages in `srcStageMask`, as specified in the table of supported access types

- Any access flag included in `dstAccessMask` must be supported by one of the pipeline stages in `dstStageMask`, as specified in the table of supported access types

- If `dependencyFlags` includes `VK_DEPENDENCY_VIEW_LOCAL_BIT`, `srcSubpass` must not be equal to `VK_SUBPASS_EXTERNAL`

- If `dependencyFlags` includes `VK_DEPENDENCY_VIEW_LOCAL_BIT`, `dstSubpass` must not be equal to `VK_SUBPASS_EXTERNAL`

- If `srcSubpass` equals `dstSubpass`, and `srcStageMask` and `dstStageMask` both include a framebuffer-space stage, then `dependencyFlags` must include `VK_DEPENDENCY_BY_REGION_BIT`

- If `viewOffset` is not equal to `0`, `srcSubpass` must not be equal to `dstSubpass`

- If `dependencyFlags` does not include `VK_DEPENDENCY_VIEW_LOCAL_BIT`, `viewOffset` must be `0`

- If `viewOffset` is not `0`, `srcSubpass` must not be equal to `dstSubpass`.

- If the mesh shaders feature is not enabled, `srcStageMask` must not contain `VK_PIPELINE_STAGE_MESH_SHADER_BIT_NV`

- If the task shaders feature is not enabled, `srcStageMask` must not contain `VK_PIPELINE_STAGE_TASK_SHADER_BIT_NV`

- If the mesh shaders feature is not enabled, `dstStageMask` must not contain `VK_PIPELINE_STAGE_MESH_SHADER_BIT_NV`

- If the task shaders feature is not enabled, `dstStageMask` must not contain `VK_PIPELINE_STAGE_TASK_SHADER_BIT_NV`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SUBPASS_DEPENDENCY_2`

- `srcStageMask` must be a valid combination of VkPipelineStageFlagBits values

- `srcStageMask` must not be `0`

- `dstStageMask` must be a valid combination of VkPipelineStageFlagBits values

- `dstStageMask` must not be `0`

- `srcAccessMask` must be a valid combination of VkAccessFlagBits values

- `dstAccessMask` must be a valid combination of VkAccessFlagBits values

- `dependencyFlags` must be a valid combination of VkDependencyFlagBits values

To destroy a render pass, call:

    void vkDestroyRenderPass(
        VkDevice                                    device,
        VkRenderPass                                renderPass,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that destroys the render pass.

- `renderPass` is the handle of the render pass to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage

- All submitted commands that refer to `renderPass` must have completed execution

- If `VkAllocationCallbacks` were provided when `renderPass` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `renderPass` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `renderPass` is not VK_NULL_HANDLE, `renderPass` must be a valid VkRenderPass handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- If `renderPass` is a valid handle, it must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `renderPass` must be externally synchronized

### 7.2. Render Pass Compatibility

Framebuffers and graphics pipelines are created based on a specific render pass object. They must only be used with that render pass object, or one compatible with it.

Two attachment references are compatible if they have matching format and sample count, or are both `VK_ATTACHMENT_UNUSED` or the pointer that would contain the reference is `NULL`.

Two arrays of attachment references are compatible if all corresponding pairs of attachments are compatible. If the arrays are of different lengths, attachment references not present in the smaller array are treated as `VK_ATTACHMENT_UNUSED`.

Two render passes are compatible if their corresponding color, input, resolve, and depth/stencil attachment references are compatible and if they are otherwise identical except for:

- Initial and final image layout in attachment descriptions

- Load and store operations in attachment descriptions

- Image layout in attachment references

As an additional special case, if two render passes have a single subpass, the resolve attachment reference and depth/stencil resolve mode compatibility requirements are ignored.

A framebuffer is compatible with a render pass if it was created using the same render pass or a compatible render pass.

### 7.3. Framebuffers

Render passes operate in conjunction with framebuffers. Framebuffers represent a collection of specific memory attachments that a render pass instance uses.

Framebuffers are represented by `VkFramebuffer` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkFramebuffer)

To create a framebuffer, call:

    VkResult vkCreateFramebuffer(
        VkDevice                                    device,
        const VkFramebufferCreateInfo*              pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkFramebuffer*                              pFramebuffer);

- `device` is the logical device that creates the framebuffer.

- `pCreateInfo` is a pointer to a VkFramebufferCreateInfo structure describing additional information about framebuffer creation.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pFramebuffer` is a pointer to a VkFramebuffer handle in which the resulting framebuffer object is returned.

Valid Usage

- If `pCreateInfo->flags` does not include `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, and `attachmentCount` is not `0`, each element of `pCreateInfo->pAttachments` must have been created on `device`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkFramebufferCreateInfo structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pFramebuffer` must be a valid pointer to a VkFramebuffer handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkFramebufferCreateInfo` structure is defined as:

    typedef struct VkFramebufferCreateInfo {
        VkStructureType             sType;
        const void*                 pNext;
        VkFramebufferCreateFlags    flags;
        VkRenderPass                renderPass;
        uint32_t                    attachmentCount;
        const VkImageView*          pAttachments;
        uint32_t                    width;
        uint32_t                    height;
        uint32_t                    layers;
    } VkFramebufferCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkFramebufferCreateFlagBits

- `renderPass` is a render pass defining what render passes the framebuffer will be compatible with. See Render Pass Compatibility for details.

- `attachmentCount` is the number of attachments.

- `pAttachments` is a pointer to an array of VkImageView handles, each of which will be used as the corresponding attachment in a render pass instance. If `flags` includes `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, this parameter is ignored.

- `width`, `height` and `layers` define the dimensions of the framebuffer. If the render pass uses multiview, then `layers` must be one and each attachment requires a number of layers that is greater than the maximum bit index set in the view mask in the subpasses in which it is used.

Applications must ensure that all accesses to memory that backs image subresources used as attachments in a given renderpass instance either happen-before the load operations for those attachments, or happen-after the store operations for those attachments.

For depth/stencil attachments, each aspect can be used separately as attachments and non-attachments as long as the non-attachment accesses are also via an image subresource in either the `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL` layout or the `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL` layout, and the attachment resource uses whichever of those two layouts the image accesses do not. Use of non-attachment aspects in this case is only well defined if the attachment is used in the subpass where the non-attachment access is being made, or the layout of the image subresource is constant throughout the entire render pass instance, including the `initialLayout` and `finalLayout`.

| Note These restrictions mean that the render pass has full knowledge of all uses of all of the attachments, so that the implementation is able to make correct decisions about when and how to perform layout transitions, when to overlap execution of subpasses, etc.

It is legal for a subpass to use no color or depth/stencil attachments, and rather use shader side effects such as image stores and atomics to produce an output. In this case, the subpass continues to use the `width`, `height`, and `layers` of the framebuffer to define the dimensions of the rendering area, and the `rasterizationSamples` from each pipeline’s VkPipelineMultisampleStateCreateInfo to define the number of samples used in rasterization; however, if VkPhysicalDeviceFeatures::`variableMultisampleRate` is `VK_FALSE`, then all pipelines to be bound with a given zero-attachment subpass must have the same value for VkPipelineMultisampleStateCreateInfo::`rasterizationSamples`.

Valid Usage

- `attachmentCount` must be equal to the attachment count specified in `renderPass`

- If `flags` does not include `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, and `attachmentCount` is not `0`, `pAttachments` must be a valid pointer to an array of `attachmentCount` valid VkImageView handles

- If `flags` does not include `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, each element of `pAttachments` that is used as a color attachment or resolve attachment by `renderPass` must have been created with a `usage` value including `VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT`

- If `flags` does not include `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, each element of `pAttachments` that is used as a depth/stencil attachment by `renderPass` must have been created with a `usage` value including `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT`

- If `flags` does not include `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, each element of `pAttachments` that is used as a depth/stencil resolve attachment by `renderPass` must have been created with a `usage` value including `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT`

- If `flags` does not include `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, each element of `pAttachments` that is used as an input attachment by `renderPass` must have been created with a `usage` value including `VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT`

- Each element of `pAttachments` that is used as a fragment density map attachment by `renderPass` must not have been created with a `flags` value including `VK_IMAGE_CREATE_SUBSAMPLED_BIT_EXT`.

- If `renderPass` has a fragment density map attachment and non-subsample image feature is not enabled, each element of `pAttachments` must have been created with a `flags` value including `VK_IMAGE_CREATE_SUBSAMPLED_BIT_EXT` unless that element is the fragment density map attachment.

- If `flags` does not include `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, each element of `pAttachments` must have been created with a VkFormat value that matches the VkFormat specified by the corresponding `VkAttachmentDescription` in `renderPass`

- If `flags` does not include `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, each element of `pAttachments` must have been created with a `samples` value that matches the `samples` value specified by the corresponding `VkAttachmentDescription` in `renderPass`

- If `flags` does not include `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, each element of `pAttachments` must have dimensions at least as large as the corresponding framebuffer dimension except for any element that is referenced by `fragmentDensityMapAttachment`

- If `renderPass` was specified with non-zero view masks, each element of `pAttachments` that is not referenced by `fragmentDensityMapAttachment` must have a `layerCount` greater than the index of the most significant bit set in any of those view masks

- If `renderPass` was specified with non-zero view masks, each element of `pAttachments` that is referenced by `fragmentDensityMapAttachment` must have a `layerCount` equal to `1` or greater than the index of the most significant bit set in any of those view masks

- If `renderPass` was not specified with non-zero view masks, each element of `pAttachments` that is referenced by `fragmentDensityMapAttachment` must have a `layerCount` equal to `1`

- If `flags` does not include `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, an element of `pAttachments` that is referenced by `fragmentDensityMapAttachment` must have a width at least as large as \(\lceil{\frac{width}{maxFragmentDensityTexelSize_{width}}}\rceil\)

- If `flags` does not include `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, an element of `pAttachments` that is referenced by `fragmentDensityMapAttachment` must have a height at least as large as \(\lceil{\frac{height}{maxFragmentDensityTexelSize_{height}}}\rceil\)

- If `flags` does not include `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, each element of `pAttachments` must only specify a single mip level

- If `flags` does not include `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, each element of `pAttachments` must have been created with the identity swizzle

- `width` must be greater than `0`.

- `width` must be less than or equal to `VkPhysicalDeviceLimits`::`maxFramebufferWidth`

- `height` must be greater than `0`.

- `height` must be less than or equal to `VkPhysicalDeviceLimits`::`maxFramebufferHeight`

- `layers` must be greater than `0`.

- `layers` must be less than or equal to `VkPhysicalDeviceLimits`::`maxFramebufferLayers`

- If `renderPass` was specified with non-zero view masks, `layers` must be `1`

- If `flags` does not include `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, each element of `pAttachments` that is a 2D or 2D array image view taken from a 3D image must not be a depth/stencil format

- If `flags` does not include `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, and `attachmentCount` is not 0, `pAttachments` must be a valid pointer to an array of `attachmentCount` valid VkImageView handles

- If the imageless framebuffer feature is not enabled, `flags` must not include `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`

- If `flags` includes `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, the `pNext` chain must include a VkFramebufferAttachmentsCreateInfo structure

- If `flags` includes `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, the `attachmentImageInfoCount` member of a VkFramebufferAttachmentsCreateInfo structure included in the `pNext` chain must be equal to either zero or `attachmentCount`

- If `flags` includes `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, the `width` member of any element of the `pAttachmentImageInfos` member of a VkFramebufferAttachmentsCreateInfo structure included in the `pNext` chain must be greater than or equal to `width`, except for any element that is referenced by VkRenderPassFragmentDensityMapCreateInfoEXT::`fragmentDensityMapAttachment` in `renderPass`

- If `flags` includes `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, the `height` member of any element of the `pAttachmentImageInfos` member of a VkFramebufferAttachmentsCreateInfo structure included in the `pNext` chain must be greater than or equal to `height`, except for any element that is referenced by VkRenderPassFragmentDensityMapCreateInfoEXT::`fragmentDensityMapAttachment` in `renderPass`

- If `flags` includes `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, the `width` member of any element of the `pAttachmentImageInfos` member of a VkFramebufferAttachmentsCreateInfo structure included in the `pNext` chain that is referenced by VkRenderPassFragmentDensityMapCreateInfoEXT::`fragmentDensityMapAttachment` in `renderPass` must be greater than or equal to \(\lceil{\frac{width}{maxFragmentDensityTexelSize_{width}}}\rceil\)

- If `flags` includes `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, the `height` member of any element of the `pAttachmentImageInfos` member of a VkFramebufferAttachmentsCreateInfo structure included in the `pNext` chain that is referenced by VkRenderPassFragmentDensityMapCreateInfoEXT::`fragmentDensityMapAttachment` in `renderPass` must be greater than or equal to \(\lceil{\frac{height}{maxFragmentDensityTexelSize_{height}}}\rceil\)

- If multiview is enabled for `renderPass`, and `flags` includes `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, the `layerCount` member of any element of the `pAttachmentImageInfos` member of a VkFramebufferAttachmentsCreateInfo structure included in the `pNext` chain must be greater than the maximum bit index set in the view mask in the subpasses in which it is used in `renderPass`

- If multiview is not enabled for `renderPass`, and `flags` includes `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, the `layerCount` member of any element of the `pAttachmentImageInfos` member of a VkFramebufferAttachmentsCreateInfo structure included in the `pNext` chain must be greater than or equal to `layers`

- If `flags` includes `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, the `usage` member of any element of the `pAttachmentImageInfos` member of a VkFramebufferAttachmentsCreateInfo structure included in the `pNext` chain that refers to an attachment used as a color attachment or resolve attachment by `renderPass` must include `VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT`

- If `flags` includes `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, the `usage` member of any element of the `pAttachmentImageInfos` member of a VkFramebufferAttachmentsCreateInfo structure included in the `pNext` chain that refers to an attachment used as a depth/stencil attachment by `renderPass` must include `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT`

- If `flags` includes `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, the `usage` member of any element of the `pAttachmentImageInfos` member of a VkFramebufferAttachmentsCreateInfo structure included in the `pNext` chain that refers to an attachment used as a depth/stencil resolve attachment by `renderPass` must include `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT`

- If `flags` includes `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, the `usage` member of any element of the `pAttachmentImageInfos` member of a VkFramebufferAttachmentsCreateInfo structure included in the `pNext` chain that refers to an attachment used as an input attachment by `renderPass` must include `VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT`

- If `flags` includes `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, at least one element of the `pViewFormats` member of any element of the `pAttachmentImageInfos` member of a VkFramebufferAttachmentsCreateInfo structure included in the `pNext` chain must be equal to the corresponding value of VkAttachmentDescription::`format` used to create `renderPass`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO`

- `pNext` must be `NULL` or a pointer to a valid instance of VkFramebufferAttachmentsCreateInfo

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be a valid combination of VkFramebufferCreateFlagBits values

- `renderPass` must be a valid VkRenderPass handle

- Both of `renderPass`, and the elements of `pAttachments` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

The `VkFramebufferAttachmentsCreateInfo` structure is defined as:

    typedef struct VkFramebufferAttachmentsCreateInfo {
        VkStructureType                            sType;
        const void*                                pNext;
        uint32_t                                   attachmentImageInfoCount;
        const VkFramebufferAttachmentImageInfo*    pAttachmentImageInfos;
    } VkFramebufferAttachmentsCreateInfo;

or the equivalent

    typedef VkFramebufferAttachmentsCreateInfo VkFramebufferAttachmentsCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `attachmentImageInfoCount` is the number of attachments being described.

- `pAttachmentImageInfos` is a pointer to an array of VkFramebufferAttachmentImageInfo instances, each of which describes a number of parameters of the corresponding attachment in a render pass instance.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_FRAMEBUFFER_ATTACHMENTS_CREATE_INFO`

- If `attachmentImageInfoCount` is not `0`, `pAttachmentImageInfos` must be a valid pointer to an array of `attachmentImageInfoCount` valid VkFramebufferAttachmentImageInfo structures

The `VkFramebufferAttachmentImageInfo` structure is defined as:

    typedef struct VkFramebufferAttachmentImageInfo {
        VkStructureType       sType;
        const void*           pNext;
        VkImageCreateFlags    flags;
        VkImageUsageFlags     usage;
        uint32_t              width;
        uint32_t              height;
        uint32_t              layerCount;
        uint32_t              viewFormatCount;
        const VkFormat*       pViewFormats;
    } VkFramebufferAttachmentImageInfo;

or the equivalent

    typedef VkFramebufferAttachmentImageInfo VkFramebufferAttachmentImageInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkImageCreateFlagBits, matching the value of VkImageCreateInfo::`flags` used to create an image that will be used with this framebuffer.

- `usage` is a bitmask of VkImageUsageFlagBits, matching the value of VkImageCreateInfo::`usage` used to create an image used with this framebuffer.

- `width` is the width of the image view used for rendering.

- `height` is the height of the image view used for rendering.

- `viewFormatCount` is the number of entries in the `pViewFormats` array, matching the value of VkImageFormatListCreateInfo::`viewFormatCount` used to create an image used with this framebuffer.

- `pViewFormats` is an array which lists of all formats which can be used when creating views of the image, matching the value of VkImageFormatListCreateInfo::pViewFormats used to create an image used with this framebuffer.

Images that can be used with the framebuffer when beginning a render pass, as specified by VkRenderPassAttachmentBeginInfo, must be created with parameters that are identical to those specified here.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_FRAMEBUFFER_ATTACHMENT_IMAGE_INFO`

- `pNext` must be `NULL`

- `flags` must be a valid combination of VkImageCreateFlagBits values

- `usage` must be a valid combination of VkImageUsageFlagBits values

- `usage` must not be `0`

- If `viewFormatCount` is not `0`, `pViewFormats` must be a valid pointer to an array of `viewFormatCount` valid VkFormat values

Bits which can be set in VkFramebufferCreateInfo::`flags` to specify options for framebuffers are:

    typedef enum VkFramebufferCreateFlagBits {
        VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT = 0x00000001,
        VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT_KHR = VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT,
        VK_FRAMEBUFFER_CREATE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkFramebufferCreateFlagBits;

- `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT` specifies that image views are not specified, and only attachment compatibility information will be provided via a VkFramebufferAttachmentImageInfo structure.

    typedef VkFlags VkFramebufferCreateFlags;

`VkFramebufferCreateFlags` is a bitmask type for setting a mask of zero or more VkFramebufferCreateFlagBits.

To destroy a framebuffer, call:

    void vkDestroyFramebuffer(
        VkDevice                                    device,
        VkFramebuffer                               framebuffer,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that destroys the framebuffer.

- `framebuffer` is the handle of the framebuffer to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage

- All submitted commands that refer to `framebuffer` must have completed execution

- If `VkAllocationCallbacks` were provided when `framebuffer` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `framebuffer` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `framebuffer` is not VK_NULL_HANDLE, `framebuffer` must be a valid VkFramebuffer handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- If `framebuffer` is a valid handle, it must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `framebuffer` must be externally synchronized

### 7.4. Render Pass Commands

An application records the commands for a render pass instance one subpass at a time, by beginning a render pass instance, iterating over the subpasses to record commands for that subpass, and then ending the render pass instance.

To begin a render pass instance, call:

    void vkCmdBeginRenderPass(
        VkCommandBuffer                             commandBuffer,
        const VkRenderPassBeginInfo*                pRenderPassBegin,
        VkSubpassContents                           contents);

- `commandBuffer` is the command buffer in which to record the command.

- `pRenderPassBegin` is a pointer to a VkRenderPassBeginInfo structure specifying the render pass to begin an instance of, and the framebuffer the instance uses.

- `contents` is a VkSubpassContents value specifying how the commands in the first subpass will be provided.

After beginning a render pass instance, the command buffer is ready to record the commands for the first subpass of that render pass.

Valid Usage

- If any of the `initialLayout` or `finalLayout` member of the `VkAttachmentDescription` structures or the `layout` member of the `VkAttachmentReference` structures specified when creating the render pass specified in the `renderPass` member of `pRenderPassBegin` is `VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL` then the corresponding attachment image view of the framebuffer specified in the `framebuffer` member of `pRenderPassBegin` must have been created with a `usage` value including `VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT`

- If any of the `initialLayout` or `finalLayout` member of the `VkAttachmentDescription` structures or the `layout` member of the `VkAttachmentReference` structures specified when creating the render pass specified in the `renderPass` member of `pRenderPassBegin` is `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL`, or `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL` then the corresponding attachment image view of the framebuffer specified in the `framebuffer` member of `pRenderPassBegin` must have been created with a `usage` value including `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT`

- If any of the `initialLayout` or `finalLayout` member of the `VkAttachmentDescription` structures or the `layout` member of the `VkAttachmentReference` structures specified when creating the render pass specified in the `renderPass` member of `pRenderPassBegin` is `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL`, or `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL`, or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL` then the corresponding attachment image view of the framebuffer specified in the `framebuffer` member of `pRenderPassBegin` must have been created with a `usage` value including `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT`

- If any of the `stencilInitialLayout` or `stencilFinalLayout` member of the `VkAttachmentDescriptionStencilLayout` structures or the `stencilLayout` member of the `VkAttachmentReferenceStencilLayout` structures specified when creating the render pass specified in the `renderPass` member of `pRenderPassBegin` is `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL`, or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL` then the corresponding attachment image view of the framebuffer specified in the `framebuffer` member of `pRenderPassBegin` must have been created with a `usage` value including `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT`

- If any of the `initialLayout` or `finalLayout` member of the `VkAttachmentDescription` structures or the `layout` member of the `VkAttachmentReference` structures specified when creating the render pass specified in the `renderPass` member of `pRenderPassBegin` is `VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL` then the corresponding attachment image view of the framebuffer specified in the `framebuffer` member of `pRenderPassBegin` must have been created with a `usage` value including `VK_IMAGE_USAGE_SAMPLED_BIT` or `VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT`

- If any of the `initialLayout` or `finalLayout` member of the `VkAttachmentDescription` structures or the `layout` member of the `VkAttachmentReference` structures specified when creating the render pass specified in the `renderPass` member of `pRenderPassBegin` is `VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL` then the corresponding attachment image view of the framebuffer specified in the `framebuffer` member of `pRenderPassBegin` must have been created with a `usage` value including `VK_IMAGE_USAGE_TRANSFER_SRC_BIT`

- If any of the `initialLayout` or `finalLayout` member of the `VkAttachmentDescription` structures or the `layout` member of the `VkAttachmentReference` structures specified when creating the render pass specified in the `renderPass` member of `pRenderPassBegin` is `VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL` then the corresponding attachment image view of the framebuffer specified in the `framebuffer` member of `pRenderPassBegin` must have been created with a `usage` value including `VK_IMAGE_USAGE_TRANSFER_DST_BIT`

- If any of the `initialLayout` members of the `VkAttachmentDescription` structures specified when creating the render pass specified in the `renderPass` member of `pRenderPassBegin` is not `VK_IMAGE_LAYOUT_UNDEFINED`, then each such `initialLayout` must be equal to the current layout of the corresponding attachment image subresource of the framebuffer specified in the `framebuffer` member of `pRenderPassBegin`

- The `srcStageMask` and `dstStageMask` members of any element of the `pDependencies` member of VkRenderPassCreateInfo used to create `renderPass` must be supported by the capabilities of the queue family identified by the `queueFamilyIndex` member of the VkCommandPoolCreateInfo used to create the command pool which `commandBuffer` was allocated from

- For any attachment in `framebuffer` that is used by `renderPass` and is bound to memory locations that are also bound to another attachment used by `renderPass`, and if at least one of those uses causes either attachment to be written to, both attachments must have had the `VK_ATTACHMENT_DESCRIPTION_MAY_ALIAS_BIT` set

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pRenderPassBegin` must be a valid pointer to a valid VkRenderPassBeginInfo structure

- `contents` must be a valid VkSubpassContents value

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- This command must only be called outside of a render pass instance

- `commandBuffer` must be a primary `VkCommandBuffer`

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary | Outside | Graphics | Graphics

Alternatively to begin a render pass, call:

    void vkCmdBeginRenderPass2(
        VkCommandBuffer                             commandBuffer,
        const VkRenderPassBeginInfo*                pRenderPassBegin,
        const VkSubpassBeginInfo*                   pSubpassBeginInfo);

or the equivalent command

    void vkCmdBeginRenderPass2KHR(
        VkCommandBuffer                             commandBuffer,
        const VkRenderPassBeginInfo*                pRenderPassBegin,
        const VkSubpassBeginInfo*                   pSubpassBeginInfo);

- `commandBuffer` is the command buffer in which to record the command.

- `pRenderPassBegin` is a pointer to a VkRenderPassBeginInfo structure specifying the render pass to begin an instance of, and the framebuffer the instance uses.

- `pSubpassBeginInfo` is a pointer to a VkSubpassBeginInfo structure containing information about the subpass which is about to begin rendering.

After beginning a render pass instance, the command buffer is ready to record the commands for the first subpass of that render pass.

Valid Usage

- Both the `framebuffer` and `renderPass` members of `pRenderPassBegin` must have been created on the same VkDevice that `commandBuffer` was allocated on

- If any of the `initialLayout` or `finalLayout` member of the `VkAttachmentDescription` structures or the `layout` member of the `VkAttachmentReference` structures specified when creating the render pass specified in the `renderPass` member of `pRenderPassBegin` is `VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL` then the corresponding attachment image view of the framebuffer specified in the `framebuffer` member of `pRenderPassBegin` must have been created with a `usage` value including `VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT`

- If any of the `initialLayout` or `finalLayout` member of the `VkAttachmentDescription` structures or the `layout` member of the `VkAttachmentReference` structures specified when creating the render pass specified in the `renderPass` member of `pRenderPassBegin` is `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL`, or `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL` then the corresponding attachment image view of the framebuffer specified in the `framebuffer` member of `pRenderPassBegin` must have been created with a `usage` value including `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT`

- If any of the `initialLayout` or `finalLayout` member of the `VkAttachmentDescription` structures or the `layout` member of the `VkAttachmentReference` structures specified when creating the render pass specified in the `renderPass` member of `pRenderPassBegin` is `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL`, or `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL`, or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL` then the corresponding attachment image view of the framebuffer specified in the `framebuffer` member of `pRenderPassBegin` must have been created with a `usage` value including `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT`

- If any of the `stencilInitialLayout` or `stencilFinalLayout` member of the `VkAttachmentDescriptionStencilLayout` structures or the `stencilLayout` member of the `VkAttachmentReferenceStencilLayout` structures specified when creating the render pass specified in the `renderPass` member of `pRenderPassBegin` is `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL`, or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL` then the corresponding attachment image view of the framebuffer specified in the `framebuffer` member of `pRenderPassBegin` must have been created with a `usage` value including `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT`

- If any of the `initialLayout` or `finalLayout` member of the `VkAttachmentDescription` structures or the `layout` member of the `VkAttachmentReference` structures specified when creating the render pass specified in the `renderPass` member of `pRenderPassBegin` is `VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL` then the corresponding attachment image view of the framebuffer specified in the `framebuffer` member of `pRenderPassBegin` must have been created with a `usage` value including `VK_IMAGE_USAGE_SAMPLED_BIT` or `VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT`

- If any of the `initialLayout` or `finalLayout` member of the `VkAttachmentDescription` structures or the `layout` member of the `VkAttachmentReference` structures specified when creating the render pass specified in the `renderPass` member of `pRenderPassBegin` is `VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL` then the corresponding attachment image view of the framebuffer specified in the `framebuffer` member of `pRenderPassBegin` must have been created with a `usage` value including `VK_IMAGE_USAGE_TRANSFER_SRC_BIT`

- If any of the `initialLayout` or `finalLayout` member of the `VkAttachmentDescription` structures or the `layout` member of the `VkAttachmentReference` structures specified when creating the render pass specified in the `renderPass` member of `pRenderPassBegin` is `VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL` then the corresponding attachment image view of the framebuffer specified in the `framebuffer` member of `pRenderPassBegin` must have been created with a `usage` value including `VK_IMAGE_USAGE_TRANSFER_DST_BIT`

- If any of the `initialLayout` members of the `VkAttachmentDescription` structures specified when creating the render pass specified in the `renderPass` member of `pRenderPassBegin` is not `VK_IMAGE_LAYOUT_UNDEFINED`, then each such `initialLayout` must be equal to the current layout of the corresponding attachment image subresource of the framebuffer specified in the `framebuffer` member of `pRenderPassBegin`

- The `srcStageMask` and `dstStageMask` members of any element of the `pDependencies` member of VkRenderPassCreateInfo used to create `renderPass` must be supported by the capabilities of the queue family identified by the `queueFamilyIndex` member of the VkCommandPoolCreateInfo used to create the command pool which `commandBuffer` was allocated from

- For any attachment in `framebuffer` that is used by `renderPass` and is bound to memory locations that are also bound to another attachment used by `renderPass`, and if at least one of those uses causes either attachment to be written to, both attachments must have had the `VK_ATTACHMENT_DESCRIPTION_MAY_ALIAS_BIT` set

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pRenderPassBegin` must be a valid pointer to a valid VkRenderPassBeginInfo structure

- `pSubpassBeginInfo` must be a valid pointer to a valid VkSubpassBeginInfo structure

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- This command must only be called outside of a render pass instance

- `commandBuffer` must be a primary `VkCommandBuffer`

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary | Outside | Graphics | Graphics

The `VkRenderPassBeginInfo` structure is defined as:

    typedef struct VkRenderPassBeginInfo {
        VkStructureType        sType;
        const void*            pNext;
        VkRenderPass           renderPass;
        VkFramebuffer          framebuffer;
        VkRect2D               renderArea;
        uint32_t               clearValueCount;
        const VkClearValue*    pClearValues;
    } VkRenderPassBeginInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `renderPass` is the render pass to begin an instance of.

- `framebuffer` is the framebuffer containing the attachments that are used with the render pass.

- `renderArea` is the render area that is affected by the render pass instance, and is described in more detail below.

- `clearValueCount` is the number of elements in `pClearValues`.

- `pClearValues` is a pointer to an array of `clearValueCount` VkClearValue structures that contains clear values for each attachment, if the attachment uses a `loadOp` value of `VK_ATTACHMENT_LOAD_OP_CLEAR` or if the attachment has a depth/stencil format and uses a `stencilLoadOp` value of `VK_ATTACHMENT_LOAD_OP_CLEAR`. The array is indexed by attachment number. Only elements corresponding to cleared attachments are used. Other elements of `pClearValues` are ignored.

`renderArea` is the render area that is affected by the render pass instance. The effects of attachment load, store and multisample resolve operations are restricted to the pixels whose x and y coordinates fall within the render area on all attachments. The render area extends to all layers of `framebuffer`. The application must ensure (using scissor if necessary) that all rendering is contained within the render area. The render area, after any transform specified by VkRenderPassTransformBeginInfoQCOM::`transform` is applied, must be contained within the framebuffer dimensions.

If render pass transform is enabled, then `renderArea` must equal the framebuffer pre-transformed dimensions. After `renderArea` has been transformed by VkRenderPassTransformBeginInfoQCOM::`transform`, the resulting render area must be equal to the framebuffer dimensions.

When multiview is enabled, the resolve operation at the end of a subpass applies to all views in the view mask.

| Note There may be a performance cost for using a render area smaller than the framebuffer, unless it matches the render area granularity for the render pass.

Valid Usage

- `clearValueCount` must be greater than the largest attachment index in `renderPass` that specifies a `loadOp` (or `stencilLoadOp`, if the attachment has a depth/stencil format) of `VK_ATTACHMENT_LOAD_OP_CLEAR`

- `renderPass` must be compatible with the `renderPass` member of the `VkFramebufferCreateInfo` structure specified when creating `framebuffer`

- If the `pNext` chain does not contain VkDeviceGroupRenderPassBeginInfo or its `deviceRenderAreaCount` member is equal to 0, `renderArea.offset.x` must be greater than or equal to 0

- If the `pNext` chain does not contain VkDeviceGroupRenderPassBeginInfo or its `deviceRenderAreaCount` member is equal to 0, `renderArea.offset.y` must be greater than or equal to 0

- If the `pNext` chain does not contain VkDeviceGroupRenderPassBeginInfo or its `deviceRenderAreaCount` member is equal to 0, `renderArea.offset.x` + `renderArea.offset.width` must be less than or equal to VkFramebufferCreateInfo::`width` the `framebuffer` was created with

- If the `pNext` chain does not contain VkDeviceGroupRenderPassBeginInfo or its `deviceRenderAreaCount` member is equal to 0, `renderArea.offset.y` + `renderArea.offset.height` must be less than or equal to VkFramebufferCreateInfo::`height` the `framebuffer` was created with

- If the `pNext` chain contains VkDeviceGroupRenderPassBeginInfo, the `offset.x` member of each element of `pDeviceRenderAreas` must be greater than or equal to 0

- If the `pNext` chain contains VkDeviceGroupRenderPassBeginInfo, the `offset.y` member of each element of `pDeviceRenderAreas` must be greater than or equal to 0

- If the `pNext` chain contains VkDeviceGroupRenderPassBeginInfo, `offset.x` + `offset.width` of each element of `pDeviceRenderAreas` must be less than or equal to VkFramebufferCreateInfo::`width` the `framebuffer` was created with

- If the `pNext` chain contains VkDeviceGroupRenderPassBeginInfo, `offset.y` + `offset.height` of each element of `pDeviceRenderAreas` must be less than or equal to VkFramebufferCreateInfo::`height` the `framebuffer` was created with

- If `framebuffer` was created with a VkFramebufferCreateInfo::`flags` value that did not include `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, and the `pNext` chain includes a VkRenderPassAttachmentBeginInfo structure, its `attachmentCount` must be zero

- If `framebuffer` was created with a VkFramebufferCreateInfo::`flags` value that included `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, the `attachmentCount` of a VkRenderPassAttachmentBeginInfo structure included in the `pNext` chain must be equal to the value of VkFramebufferAttachmentsCreateInfo::`attachmentImageInfoCount` used to create `framebuffer`

- If `framebuffer` was created with a VkFramebufferCreateInfo::`flags` value that included `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT_KHR`, each element of the `pAttachments` member of a VkRenderPassAttachmentBeginInfo structure included in the `pNext` chain must have been created on the same VkDevice as `framebuffer` and `renderPass`

- If `framebuffer` was created with a VkFramebufferCreateInfo::`flags` value that included `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, each element of the `pAttachments` member of a VkRenderPassAttachmentBeginInfo structure included in the `pNext` chain must be a VkImageView of an image created with a value of VkImageCreateInfo::`flags` equal to the `flags` member of the corresponding element of VkFramebufferAttachmentsCreateInfoKHR::`pAttachments` used to create `framebuffer`

- If `framebuffer` was created with a VkFramebufferCreateInfo::`flags` value that included `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, each element of the `pAttachments` member of a VkRenderPassAttachmentBeginInfo structure included in the `pNext` chain must be a VkImageView of an image created with a value of VkImageCreateInfo::`usage` equal to the `usage` member of the corresponding element of VkFramebufferAttachmentsCreateInfo::`pAttachments` used to create `framebuffer`

- If `framebuffer` was created with a VkFramebufferCreateInfo::`flags` value that included `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, each element of the `pAttachments` member of a VkRenderPassAttachmentBeginInfo structure included in the `pNext` chain must be a VkImageView with a width equal to the `width` member of the corresponding element of VkFramebufferAttachmentsCreateInfo::`pAttachments` used to create `framebuffer`

- If `framebuffer` was created with a VkFramebufferCreateInfo::`flags` value that included `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, each element of the `pAttachments` member of a VkRenderPassAttachmentBeginInfo structure included in the `pNext` chain must be a VkImageView with a height equal to the `height` member of the corresponding element of VkFramebufferAttachmentsCreateInfo::`pAttachments` used to create `framebuffer`

- If `framebuffer` was created with a VkFramebufferCreateInfo::`flags` value that included `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, each element of the `pAttachments` member of a VkRenderPassAttachmentBeginInfo structure included in the `pNext` chain must be a VkImageView of an image created with a value of VkImageViewCreateInfo::`subresourceRange.layerCount` equal to the `layerCount` member of the corresponding element of VkFramebufferAttachmentsCreateInfo::`pAttachments` used to create `framebuffer`

- If `framebuffer` was created with a VkFramebufferCreateInfo::`flags` value that included `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, each element of the `pAttachments` member of a VkRenderPassAttachmentBeginInfo structure included in the `pNext` chain must be a VkImageView of an image created with a value of VkImageFormatListCreateInfo::`viewFormatCount` equal to the `viewFormatCount` member of the corresponding element of VkFramebufferAttachmentsCreateInfo::`pAttachments` used to create `framebuffer`

- If `framebuffer` was created with a VkFramebufferCreateInfo::`flags` value that included `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, each element of the `pAttachments` member of a VkRenderPassAttachmentBeginInfo structure included in the `pNext` chain must be a VkImageView of an image created with a set of elements in VkImageFormatListCreateInfo::`pViewFormats` equal to the set of elements in the `pViewFormats` member of the corresponding element of VkFramebufferAttachmentsCreateInfo::`pAttachments` used to create `framebuffer`

- If `framebuffer` was created with a VkFramebufferCreateInfo::`flags` value that included `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, each element of the `pAttachments` member of a VkRenderPassAttachmentBeginInfo structure included in the `pNext` chain must be a VkImageView of an image created with a value of VkImageViewCreateInfo::`format` equal to the corresponding value of VkAttachmentDescription::`format` in `renderPass`

- If `framebuffer` was created with a VkFramebufferCreateInfo::`flags` value that included `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT`, each element of the `pAttachments` member of a VkRenderPassAttachmentBeginInfo structure included in the `pNext` chain must be a VkImageView of an image created with a value of VkImageCreateInfo::`samples` equal to the corresponding value of VkAttachmentDescription::`samples` in `renderPass`

- If the `pNext` chain includes VkRenderPassTransformBeginInfoQCOM, `renderArea`::`offset` must equal (0,0).

- If the `pNext` chain includes VkRenderPassTransformBeginInfoQCOM, `renderArea`::`extent` transformed by VkRenderPassTransformBeginInfoQCOM::`transform` must equal the `framebuffer` dimensions.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_RENDER_PASS_BEGIN_INFO`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkDeviceGroupRenderPassBeginInfo, VkRenderPassAttachmentBeginInfo, VkRenderPassSampleLocationsBeginInfoEXT, or VkRenderPassTransformBeginInfoQCOM

- The `sType` value of each struct in the `pNext` chain must be unique

- `renderPass` must be a valid VkRenderPass handle

- `framebuffer` must be a valid VkFramebuffer handle

- If `clearValueCount` is not `0`, `pClearValues` must be a valid pointer to an array of `clearValueCount` VkClearValue unions

- Both of `framebuffer`, and `renderPass` must have been created, allocated, or retrieved from the same VkDevice

The image layout of the depth aspect of a depth/stencil attachment referring to an image created with `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT` is dependent on the last sample locations used to render to the image subresource, thus preserving the contents of such depth/stencil attachments across subpass boundaries requires the application to specify these sample locations whenever a layout transition of the attachment may occur. This information can be provided by adding a `VkRenderPassSampleLocationsBeginInfoEXT` structure to the `pNext` chain of `VkRenderPassBeginInfo`.

The `VkRenderPassSampleLocationsBeginInfoEXT` structure is defined as:

    typedef struct VkRenderPassSampleLocationsBeginInfoEXT {
        VkStructureType                          sType;
        const void*                              pNext;
        uint32_t                                 attachmentInitialSampleLocationsCount;
        const VkAttachmentSampleLocationsEXT*    pAttachmentInitialSampleLocations;
        uint32_t                                 postSubpassSampleLocationsCount;
        const VkSubpassSampleLocationsEXT*       pPostSubpassSampleLocations;
    } VkRenderPassSampleLocationsBeginInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `attachmentInitialSampleLocationsCount` is the number of elements in the `pAttachmentInitialSampleLocations` array.

- `pAttachmentInitialSampleLocations` is a pointer to an array of `attachmentInitialSampleLocationsCount` VkAttachmentSampleLocationsEXT structures specifying the attachment indices and their corresponding sample location state. Each element of `pAttachmentInitialSampleLocations` can specify the sample location state to use in the automatic layout transition performed to transition a depth/stencil attachment from the initial layout of the attachment to the image layout specified for the attachment in the first subpass using it.

- `postSubpassSampleLocationsCount` is the number of elements in the `pPostSubpassSampleLocations` array.

- `pPostSubpassSampleLocations` is a pointer to an array of `postSubpassSampleLocationsCount` VkSubpassSampleLocationsEXT structures specifying the subpass indices and their corresponding sample location state. Each element of `pPostSubpassSampleLocations` can specify the sample location state to use in the automatic layout transition performed to transition the depth/stencil attachment used by the specified subpass to the image layout specified in a dependent subpass or to the final layout of the attachment in case the specified subpass is the last subpass using that attachment. In addition, if VkPhysicalDeviceSampleLocationsPropertiesEXT::`variableSampleLocations` is `VK_FALSE`, each element of `pPostSubpassSampleLocations` must specify the sample location state that matches the sample locations used by all pipelines that will be bound to a command buffer during the specified subpass. If `variableSampleLocations` is `VK_TRUE`, the sample locations used for rasterization do not depend on `pPostSubpassSampleLocations`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_RENDER_PASS_SAMPLE_LOCATIONS_BEGIN_INFO_EXT`

- If `attachmentInitialSampleLocationsCount` is not `0`, `pAttachmentInitialSampleLocations` must be a valid pointer to an array of `attachmentInitialSampleLocationsCount` valid VkAttachmentSampleLocationsEXT structures

- If `postSubpassSampleLocationsCount` is not `0`, `pPostSubpassSampleLocations` must be a valid pointer to an array of `postSubpassSampleLocationsCount` valid VkSubpassSampleLocationsEXT structures

The `VkAttachmentSampleLocationsEXT` structure is defined as:

    typedef struct VkAttachmentSampleLocationsEXT {
        uint32_t                    attachmentIndex;
        VkSampleLocationsInfoEXT    sampleLocationsInfo;
    } VkAttachmentSampleLocationsEXT;

- `attachmentIndex` is the index of the attachment for which the sample locations state is provided.

- `sampleLocationsInfo` is the sample locations state to use for the layout transition of the given attachment from the initial layout of the attachment to the image layout specified for the attachment in the first subpass using it.

If the image referenced by the framebuffer attachment at index `attachmentIndex` was not created with `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT` then the values specified in `sampleLocationsInfo` are ignored.

Valid Usage

- `attachmentIndex` must be less than the `attachmentCount` specified in VkRenderPassCreateInfo the render pass specified by VkRenderPassBeginInfo::`renderPass` was created with

Valid Usage (Implicit)

- `sampleLocationsInfo` must be a valid VkSampleLocationsInfoEXT structure

The `VkSubpassSampleLocationsEXT` structure is defined as:

    typedef struct VkSubpassSampleLocationsEXT {
        uint32_t                    subpassIndex;
        VkSampleLocationsInfoEXT    sampleLocationsInfo;
    } VkSubpassSampleLocationsEXT;

- `subpassIndex` is the index of the subpass for which the sample locations state is provided.

- `sampleLocationsInfo` is the sample locations state to use for the layout transition of the depth/stencil attachment away from the image layout the attachment is used with in the subpass specified in `subpassIndex`.

If the image referenced by the depth/stencil attachment used in the subpass identified by `subpassIndex` was not created with `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT` or if the subpass does not use a depth/stencil attachment, and VkPhysicalDeviceSampleLocationsPropertiesEXT::`variableSampleLocations` is `VK_TRUE` then the values specified in `sampleLocationsInfo` are ignored.

Valid Usage

- `subpassIndex` must be less than the `subpassCount` specified in VkRenderPassCreateInfo the render pass specified by VkRenderPassBeginInfo::`renderPass` was created with

Valid Usage (Implicit)

- `sampleLocationsInfo` must be a valid VkSampleLocationsInfoEXT structure

To begin a renderpass instance with render pass transform enabled, add the VkRenderPassTransformBeginInfoQCOM to the `pNext` chain of VkRenderPassBeginInfo structure passed to the vkCmdBeginRenderPass command specifying the renderpass transform.

The `VkRenderPassTransformBeginInfoQCOM` structure is defined as:

    typedef struct VkRenderPassTransformBeginInfoQCOM {
        VkStructureType                  sType;
        void*                            pNext;
        VkSurfaceTransformFlagBitsKHR    transform;
    } VkRenderPassTransformBeginInfoQCOM;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `transform` is a VkSurfaceTransformFlagBitsKHR value describing the transform to be applied applied to rasterization.

Valid Usage

- `transform` must be VK_SURFACE_TRANSFORM_IDENTITY_BIT_KHR, VK_SURFACE_TRANSFORM_ROTATE_90_BIT_KHR, VK_SURFACE_TRANSFORM_ROTATE_180_BIT_KHR, or VK_SURFACE_TRANSFORM_ROTATE_270_BIT_KHR.

- The renderpass must have been created with VkRenderPassCreateInfo::`flags` containing VK_RENDER_PASS_CREATE_TRANSFORM_BIT_QCOM.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_RENDER_PASS_TRANSFORM_BEGIN_INFO_QCOM`

The `VkSubpassBeginInfo` structure is defined as:

    typedef struct VkSubpassBeginInfo {
        VkStructureType      sType;
        const void*          pNext;
        VkSubpassContents    contents;
    } VkSubpassBeginInfo;

or the equivalent

    typedef VkSubpassBeginInfo VkSubpassBeginInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `contents` is a VkSubpassContents value specifying how the commands in the next subpass will be provided.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SUBPASS_BEGIN_INFO`

- `pNext` must be `NULL`

- `contents` must be a valid VkSubpassContents value

Possible values of vkCmdBeginRenderPass::`contents`, specifying how the commands in the first subpass will be provided, are:

    typedef enum VkSubpassContents {
        VK_SUBPASS_CONTENTS_INLINE = 0,
        VK_SUBPASS_CONTENTS_SECONDARY_COMMAND_BUFFERS = 1,
        VK_SUBPASS_CONTENTS_MAX_ENUM = 0x7FFFFFFF
    } VkSubpassContents;

- `VK_SUBPASS_CONTENTS_INLINE` specifies that the contents of the subpass will be recorded inline in the primary command buffer, and secondary command buffers must not be executed within the subpass.

- `VK_SUBPASS_CONTENTS_SECONDARY_COMMAND_BUFFERS` specifies that the contents are recorded in secondary command buffers that will be called from the primary command buffer, and vkCmdExecuteCommands is the only valid command on the command buffer until vkCmdNextSubpass or vkCmdEndRenderPass.

If the `pNext` chain of VkRenderPassBeginInfo includes a `VkDeviceGroupRenderPassBeginInfo` structure, then that structure includes a device mask and set of render areas for the render pass instance.

The `VkDeviceGroupRenderPassBeginInfo` structure is defined as:

    typedef struct VkDeviceGroupRenderPassBeginInfo {
        VkStructureType    sType;
        const void*        pNext;
        uint32_t           deviceMask;
        uint32_t           deviceRenderAreaCount;
        const VkRect2D*    pDeviceRenderAreas;
    } VkDeviceGroupRenderPassBeginInfo;

or the equivalent

    typedef VkDeviceGroupRenderPassBeginInfo VkDeviceGroupRenderPassBeginInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `deviceMask` is the device mask for the render pass instance.

- `deviceRenderAreaCount` is the number of elements in the `pDeviceRenderAreas` array.

- `pDeviceRenderAreas` is a pointer to an array of VkRect2D structures defining the render area for each physical device.

The `deviceMask` serves several purposes. It is an upper bound on the set of physical devices that can be used during the render pass instance, and the initial device mask when the render pass instance begins. In addition, commands transitioning to the next subpass in the render pass instance and commands ending the render pass instance, and, accordingly render pass attachment load, store, and resolve operations and subpass dependencies corresponding to the render pass instance, are executed on the physical devices included in the device mask provided here.

If `deviceRenderAreaCount` is not zero, then the elements of `pDeviceRenderAreas` override the value of VkRenderPassBeginInfo::`renderArea`, and provide a render area specific to each physical device. These render areas serve the same purpose as VkRenderPassBeginInfo::`renderArea`, including controlling the region of attachments that are cleared by `VK_ATTACHMENT_LOAD_OP_CLEAR` and that are resolved into resolve attachments.

If this structure is not present, the render pass instance’s device mask is the value of VkDeviceGroupCommandBufferBeginInfo::`deviceMask`. If this structure is not present or if `deviceRenderAreaCount` is zero, VkRenderPassBeginInfo::`renderArea` is used for all physical devices.

Valid Usage

- `deviceMask` must be a valid device mask value

- `deviceMask` must not be zero

- `deviceMask` must be a subset of the command buffer’s initial device mask

- `deviceRenderAreaCount` must either be zero or equal to the number of physical devices in the logical device.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEVICE_GROUP_RENDER_PASS_BEGIN_INFO`

- If `deviceRenderAreaCount` is not `0`, `pDeviceRenderAreas` must be a valid pointer to an array of `deviceRenderAreaCount` VkRect2D structures

The `VkRenderPassAttachmentBeginInfo` structure is defined as:

    typedef struct VkRenderPassAttachmentBeginInfo {
        VkStructureType       sType;
        const void*           pNext;
        uint32_t              attachmentCount;
        const VkImageView*    pAttachments;
    } VkRenderPassAttachmentBeginInfo;

or the equivalent

    typedef VkRenderPassAttachmentBeginInfo VkRenderPassAttachmentBeginInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `attachmentCount` is the number of attachments.

- `pAttachments` is a pointer to an array of `VkImageView` handles, each of which will be used as the corresponding attachment in the render pass instance.

Valid Usage

- Each element of `pAttachments` must only specify a single mip level

- Each element of `pAttachments` must have been created with the identity swizzle

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_RENDER_PASS_ATTACHMENT_BEGIN_INFO`

- If `attachmentCount` is not `0`, `pAttachments` must be a valid pointer to an array of `attachmentCount` valid VkImageView handles

To query the render area granularity, call:

    void vkGetRenderAreaGranularity(
        VkDevice                                    device,
        VkRenderPass                                renderPass,
        VkExtent2D*                                 pGranularity);

- `device` is the logical device that owns the render pass.

- `renderPass` is a handle to a render pass.

- `pGranularity` is a pointer to a VkExtent2D structure in which the granularity is returned.

The conditions leading to an optimal `renderArea` are:

- the `offset.x` member in `renderArea` is a multiple of the `width` member of the returned VkExtent2D (the horizontal granularity).

- the `offset.y` member in `renderArea` is a multiple of the `height` of the returned VkExtent2D (the vertical granularity).

- either the `offset.width` member in `renderArea` is a multiple of the horizontal granularity or `offset.x`+`offset.width` is equal to the `width` of the `framebuffer` in the VkRenderPassBeginInfo.

- either the `offset.height` member in `renderArea` is a multiple of the vertical granularity or `offset.y`+`offset.height` is equal to the `height` of the `framebuffer` in the VkRenderPassBeginInfo.

Subpass dependencies are not affected by the render area, and apply to the entire image subresources attached to the framebuffer as specified in the description of automatic layout transitions. Similarly, pipeline barriers are valid even if their effect extends outside the render area.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `renderPass` must be a valid VkRenderPass handle

- `pGranularity` must be a valid pointer to a VkExtent2D structure

- `renderPass` must have been created, allocated, or retrieved from `device`

To transition to the next subpass in the render pass instance after recording the commands for a subpass, call:

    void vkCmdNextSubpass(
        VkCommandBuffer                             commandBuffer,
        VkSubpassContents                           contents);

- `commandBuffer` is the command buffer in which to record the command.

- `contents` specifies how the commands in the next subpass will be provided, in the same fashion as the corresponding parameter of vkCmdBeginRenderPass.

The subpass index for a render pass begins at zero when `vkCmdBeginRenderPass` is recorded, and increments each time `vkCmdNextSubpass` is recorded.

Moving to the next subpass automatically performs any multisample resolve operations in the subpass being ended. End-of-subpass multisample resolves are treated as color attachment writes for the purposes of synchronization. This applies to resolve operations for both color and depth/stencil attachments. That is, they are considered to execute in the `VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT` pipeline stage and their writes are synchronized with `VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT`. Synchronization between rendering within a subpass and any resolve operations at the end of the subpass occurs automatically, without need for explicit dependencies or pipeline barriers. However, if the resolve attachment is also used in a different subpass, an explicit dependency is needed.

After transitioning to the next subpass, the application can record the commands for that subpass.

Valid Usage

- The current subpass index must be less than the number of subpasses in the render pass minus one

- This command must not be recorded when transform feedback is active

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `contents` must be a valid VkSubpassContents value

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- This command must only be called inside of a render pass instance

- `commandBuffer` must be a primary `VkCommandBuffer`

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary | Inside | Graphics | Graphics

To transition to the next subpass in the render pass instance after recording the commands for a subpass, call:

    void vkCmdNextSubpass2(
        VkCommandBuffer                             commandBuffer,
        const VkSubpassBeginInfo*                   pSubpassBeginInfo,
        const VkSubpassEndInfo*                     pSubpassEndInfo);

or the equivalent command

    void vkCmdNextSubpass2KHR(
        VkCommandBuffer                             commandBuffer,
        const VkSubpassBeginInfo*                   pSubpassBeginInfo,
        const VkSubpassEndInfo*                     pSubpassEndInfo);

- `commandBuffer` is the command buffer in which to record the command.

- `pSubpassBeginInfo` is a pointer to a VkSubpassBeginInfo structure containing information about the subpass which is about to begin rendering.

- `pSubpassEndInfo` is a pointer to a VkSubpassEndInfo structure containing information about how the previous subpass will be ended.

`vkCmdNextSubpass2` is semantically identical to vkCmdNextSubpass, except that it is extensible, and that `contents` is provided as part of an extensible structure instead of as a flat parameter.

Valid Usage

- The current subpass index must be less than the number of subpasses in the render pass minus one

- This command must not be recorded when transform feedback is active

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pSubpassBeginInfo` must be a valid pointer to a valid VkSubpassBeginInfo structure

- `pSubpassEndInfo` must be a valid pointer to a valid VkSubpassEndInfo structure

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- This command must only be called inside of a render pass instance

- `commandBuffer` must be a primary `VkCommandBuffer`

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary | Inside | Graphics | Graphics

To record a command to end a render pass instance after recording the commands for the last subpass, call:

    void vkCmdEndRenderPass(
        VkCommandBuffer                             commandBuffer);

- `commandBuffer` is the command buffer in which to end the current render pass instance.

Ending a render pass instance performs any multisample resolve operations on the final subpass.

Valid Usage

- The current subpass index must be equal to the number of subpasses in the render pass minus one

- This command must not be recorded when transform feedback is active

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- This command must only be called inside of a render pass instance

- `commandBuffer` must be a primary `VkCommandBuffer`

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary | Inside | Graphics | Graphics

To record a command to end a render pass instance after recording the commands for the last subpass, call:

    void vkCmdEndRenderPass2(
        VkCommandBuffer                             commandBuffer,
        const VkSubpassEndInfo*                     pSubpassEndInfo);

or the equivalent command

    void vkCmdEndRenderPass2KHR(
        VkCommandBuffer                             commandBuffer,
        const VkSubpassEndInfo*                     pSubpassEndInfo);

- `commandBuffer` is the command buffer in which to end the current render pass instance.

- `pSubpassEndInfo` is a pointer to a VkSubpassEndInfo structure containing information about how the previous subpass will be ended.

`vkCmdEndRenderPass2` is semantically identical to vkCmdEndRenderPass, except that it is extensible.

Valid Usage

- The current subpass index must be equal to the number of subpasses in the render pass minus one

- This command must not be recorded when transform feedback is active

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pSubpassEndInfo` must be a valid pointer to a valid VkSubpassEndInfo structure

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- This command must only be called inside of a render pass instance

- `commandBuffer` must be a primary `VkCommandBuffer`

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary | Inside | Graphics | Graphics

The `VkSubpassEndInfo` structure is defined as:

    typedef struct VkSubpassEndInfo {
        VkStructureType    sType;
        const void*        pNext;
    } VkSubpassEndInfo;

or the equivalent

    typedef VkSubpassEndInfo VkSubpassEndInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SUBPASS_END_INFO`

- `pNext` must be `NULL`

## 8. Shaders

A shader specifies programmable operations that execute for each vertex, control point, tessellated vertex, primitive, fragment, or workgroup in the corresponding stage(s) of the graphics and compute pipelines.

Graphics pipelines include vertex shader execution as a result of primitive assembly, followed, if enabled, by tessellation control and evaluation shaders operating on patches, geometry shaders, if enabled, operating on primitives, and fragment shaders, if present, operating on fragments generated by Rasterization. In this specification, vertex, tessellation control, tessellation evaluation and geometry shaders are collectively referred to as vertex processing stages and occur in the logical pipeline before rasterization. The fragment shader occurs logically after rasterization.

Only the compute shader stage is included in a compute pipeline. Compute shaders operate on compute invocations in a workgroup.

Shaders can read from input variables, and read from and write to output variables. Input and output variables can be used to transfer data between shader stages, or to allow the shader to interact with values that exist in the execution environment. Similarly, the execution environment provides constants that describe capabilities.

Shader variables are associated with execution environment-provided inputs and outputs using built-in decorations in the shader. The available decorations for each stage are documented in the following subsections.

### 8.1. Shader Modules

Shader modules contain shader code and one or more entry points. Shaders are selected from a shader module by specifying an entry point as part of pipeline creation. The stages of a pipeline can use shaders that come from different modules. The shader code defining a shader module must be in the SPIR-V format, as described by the Vulkan Environment for SPIR-V appendix.

Shader modules are represented by `VkShaderModule` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkShaderModule)

To create a shader module, call:

    VkResult vkCreateShaderModule(
        VkDevice                                    device,
        const VkShaderModuleCreateInfo*             pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkShaderModule*                             pShaderModule);

- `device` is the logical device that creates the shader module.

- `pCreateInfo` is a pointer to a `VkShaderModuleCreateInfo` structure.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pShaderModule` is a pointer to a VkShaderModule handle in which the resulting shader module object is returned.

Once a shader module has been created, any entry points it contains can be used in pipeline shader stages as described in Compute Pipelines and Graphics Pipelines.

If the shader stage fails to compile `VK_ERROR_INVALID_SHADER_NV` will be generated and the compile log will be reported back to the application by `VK_EXT_debug_report` if enabled.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkShaderModuleCreateInfo structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pShaderModule` must be a valid pointer to a VkShaderModule handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_INVALID_SHADER_NV`

The `VkShaderModuleCreateInfo` structure is defined as:

    typedef struct VkShaderModuleCreateInfo {
        VkStructureType              sType;
        const void*                  pNext;
        VkShaderModuleCreateFlags    flags;
        size_t                       codeSize;
        const uint32_t*              pCode;
    } VkShaderModuleCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `codeSize` is the size, in bytes, of the code pointed to by `pCode`.

- `pCode` is a pointer to code that is used to create the shader module. The type and format of the code is determined from the content of the memory addressed by `pCode`.

Valid Usage

- `codeSize` must be greater than 0

- If `pCode` is a pointer to SPIR-V code, `codeSize` must be a multiple of 4

- `pCode` must point to either valid SPIR-V code, formatted and packed as described by the Khronos SPIR-V Specification or valid GLSL code which must be written to the `GL_KHR_vulkan_glsl` extension specification

- If `pCode` is a pointer to SPIR-V code, that code must adhere to the validation rules described by the Validation Rules within a Module section of the SPIR-V Environment appendix

- If `pCode` is a pointer to GLSL code, it must be valid GLSL code written to the `GL_KHR_vulkan_glsl` GLSL extension specification

- `pCode` must declare the `Shader` capability for SPIR-V code

- `pCode` must not declare any capability that is not supported by the API, as described by the Capabilities section of the SPIR-V Environment appendix

- If `pCode` declares any of the capabilities listed as optional in the SPIR-V Environment appendix, the corresponding feature(s) must be enabled.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SHADER_MODULE_CREATE_INFO`

- `pNext` must be `NULL` or a pointer to a valid instance of VkShaderModuleValidationCacheCreateInfoEXT

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be `0`

- `pCode` must be a valid pointer to an array of \(\textrm{codeSize} \over 4\) `uint32_t` values

    typedef VkFlags VkShaderModuleCreateFlags;

`VkShaderModuleCreateFlags` is a bitmask type for setting a mask, but is currently reserved for future use.

To use a VkValidationCacheEXT to cache shader validation results, add a VkShaderModuleValidationCacheCreateInfoEXT structure to the `pNext` chain of the VkShaderModuleCreateInfo structure, specifying the cache object to use.

The `VkShaderModuleValidationCacheCreateInfoEXT` struct is defined as:

    typedef struct VkShaderModuleValidationCacheCreateInfoEXT {
        VkStructureType         sType;
        const void*             pNext;
        VkValidationCacheEXT    validationCache;
    } VkShaderModuleValidationCacheCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `validationCache` is the validation cache object from which the results of prior validation attempts will be written, and to which new validation results for this VkShaderModule will be written (if not already present).

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SHADER_MODULE_VALIDATION_CACHE_CREATE_INFO_EXT`

- `validationCache` must be a valid VkValidationCacheEXT handle

To destroy a shader module, call:

    void vkDestroyShaderModule(
        VkDevice                                    device,
        VkShaderModule                              shaderModule,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that destroys the shader module.

- `shaderModule` is the handle of the shader module to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

A shader module can be destroyed while pipelines created using its shaders are still in use.

Valid Usage

- If `VkAllocationCallbacks` were provided when `shaderModule` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `shaderModule` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `shaderModule` is not VK_NULL_HANDLE, `shaderModule` must be a valid VkShaderModule handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- If `shaderModule` is a valid handle, it must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `shaderModule` must be externally synchronized

### 8.2. Shader Execution

At each stage of the pipeline, multiple invocations of a shader may execute simultaneously. Further, invocations of a single shader produced as the result of different commands may execute simultaneously. The relative execution order of invocations of the same shader type is undefined. Shader invocations may complete in a different order than that in which the primitives they originated from were drawn or dispatched by the application. However, fragment shader outputs are written to attachments in rasterization order.

The relative execution order of invocations of different shader types is largely undefined. However, when invoking a shader whose inputs are generated from a previous pipeline stage, the shader invocations from the previous stage are guaranteed to have executed far enough to generate input values for all required inputs.

### 8.3. Shader Memory Access Ordering

The order in which image or buffer memory is read or written by shaders is largely undefined. For some shader types (vertex, tessellation evaluation, and in some cases, fragment), even the number of shader invocations that may perform loads and stores is undefined.

In particular, the following rules apply:

- Vertex and tessellation evaluation shaders will be invoked at least once for each unique vertex, as defined in those sections.

- Fragment shaders will be invoked zero or more times, as defined in that section.

- The relative execution order of invocations of the same shader type is undefined. A store issued by a shader when working on primitive B might complete prior to a store for primitive A, even if primitive A is specified prior to primitive B. This applies even to fragment shaders; while fragment shader outputs are always written to the framebuffer in rasterization order, stores executed by fragment shader invocations are not.

- The relative execution order of invocations of different shader types is largely undefined.

| Note The above limitations on shader invocation order make some forms of synchronization between shader invocations within a single set of primitives unimplementable. For example, having one invocation poll memory written by another invocation assumes that the other invocation has been launched and will complete its writes in finite time.

The Memory Model appendix defines the terminology and rules for how to correctly communicate between shader invocations, such as when a write is Visible-To a read, and what constitutes a Data Race.

Applications must not cause a data race.

### 8.4. Shader Inputs and Outputs

Data is passed into and out of shaders using variables with input or output storage class, respectively. User-defined inputs and outputs are connected between stages by matching their `Location` decorations. Additionally, data can be provided by or communicated to special functions provided by the execution environment using `BuiltIn` decorations.

In many cases, the same `BuiltIn` decoration can be used in multiple shader stages with similar meaning. The specific behavior of variables decorated as `BuiltIn` is documented in the following sections.

### 8.5. Task Shaders

Task shaders operate in conjunction with the mesh shaders to produce a collection of primitives that will be processed by subsequent stages of the graphics pipeline. Its primary purpose is to create a variable amount of subsequent mesh shader invocations.

Task shaders are invoked via the execution of the programmable mesh shading pipeline.

The task shader has no fixed-function inputs other than variables identifying the specific workgroup and invocation. The only fixed output of the task shader is a task count, identifying the number of mesh shader workgroups to create. The task shader can write additional outputs to task memory, which can be read by all of the mesh shader workgroups it created.

#### 8.5.1. Task Shader Execution

Task workloads are formed from groups of work items called workgroups and processed by the task shader in the current graphics pipeline. A workgroup is a collection of shader invocations that execute the same shader, potentially in parallel. Task shaders execute in global workgroups which are divided into a number of local workgroups with a size that can be set by assigning a value to the `LocalSize` execution mode or via an object decorated by the `WorkgroupSize` decoration. An invocation within a local workgroup can share data with other members of the local workgroup through shared variables and issue memory and control flow barriers to synchronize with other members of the local workgroup.

### 8.6. Mesh Shaders

Mesh shaders operate in workgroups to produce a collection of primitives that will be processed by subsequent stages of the graphics pipeline. Each workgroup emits zero or more output primitives and the group of vertices and their associated data required for each output primitive.

Mesh shaders are invoked via the execution of the programmable mesh shading pipeline.

The only inputs available to the mesh shader are variables identifying the specific workgroup and invocation and, if applicable, any outputs written to task memory by the task shader that spawned the mesh shader’s workgroup. The mesh shader can operate without a task shader as well.

The invocations of the mesh shader workgroup write an output mesh, comprising a set of primitives with per-primitive attributes, a set of vertices with per-vertex attributes, and an array of indices identifying the mesh vertices that belong to each primitive. The primitives of this mesh are then processed by subsequent graphics pipeline stages, where the outputs of the mesh shader form an interface with the fragment shader.

#### 8.6.1. Mesh Shader Execution

Mesh workloads are formed from groups of work items called workgroups and processed by the mesh shader in the current graphics pipeline. A workgroup is a collection of shader invocations that execute the same shader, potentially in parallel. Mesh shaders execute in global workgroups which are divided into a number of local workgroups with a size that can be set by assigning a value to the `LocalSize` execution mode or via an object decorated by the `WorkgroupSize` decoration. An invocation within a local workgroup can share data with other members of the local workgroup through shared variables and issue memory and control flow barriers to synchronize with other members of the local workgroup.

The global workgroups may be generated explcitly via the API, or implicitly through the task shader’s work creation mechanism.

### 8.7. Vertex Shaders

Each vertex shader invocation operates on one vertex and its associated vertex attribute data, and outputs one vertex and associated data. Graphics pipelines using primitive shading must include a vertex shader, and the vertex shader stage is always the first shader stage in the graphics pipeline.

#### 8.7.1. Vertex Shader Execution

A vertex shader must be executed at least once for each vertex specified by a draw command. If the subpass includes multiple views in its view mask, the shader may be invoked separately for each view. During execution, the shader is presented with the index of the vertex and instance for which it has been invoked. Input variables declared in the vertex shader are filled by the implementation with the values of vertex attributes associated with the invocation being executed.

If the same vertex is specified multiple times in a draw command (e.g. by including the same index value multiple times in an index buffer) the implementation may reuse the results of vertex shading if it can statically determine that the vertex shader invocations will produce identical results.

| Note It is implementation-dependent when and if results of vertex shading are reused, and thus how many times the vertex shader will be executed. This is true also if the vertex shader contains stores or atomic operations (see `vertexPipelineStoresAndAtomics`).

### 8.8. Tessellation Control Shaders

The tessellation control shader is used to read an input patch provided by the application and to produce an output patch. Each tessellation control shader invocation operates on an input patch (after all control points in the patch are processed by a vertex shader) and its associated data, and outputs a single control point of the output patch and its associated data, and can also output additional per-patch data. The input patch is sized according to the `patchControlPoints` member of VkPipelineTessellationStateCreateInfo, as part of input assembly. The size of the output patch is controlled by the `OpExecutionMode` `OutputVertices` specified in the tessellation control or tessellation evaluation shaders, which must be specified in at least one of the shaders. The size of the input and output patches must each be greater than zero and less than or equal to `VkPhysicalDeviceLimits`::`maxTessellationPatchSize`.

#### 8.8.1. Tessellation Control Shader Execution

A tessellation control shader is invoked at least once for each output vertex in a patch. If the subpass includes multiple views in its view mask, the shader may be invoked separately for each view.

Inputs to the tessellation control shader are generated by the vertex shader. Each invocation of the tessellation control shader can read the attributes of any incoming vertices and their associated data. The invocations corresponding to a given patch execute logically in parallel, with undefined relative execution order. However, the `OpControlBarrier` instruction can be used to provide limited control of the execution order by synchronizing invocations within a patch, effectively dividing tessellation control shader execution into a set of phases. Tessellation control shaders will read undefined values if one invocation reads a per-vertex or per-patch attribute written by another invocation at any point during the same phase, or if two invocations attempt to write different values to the same per-patch output in a single phase.

### 8.9. Tessellation Evaluation Shaders

The Tessellation Evaluation Shader operates on an input patch of control points and their associated data, and a single input barycentric coordinate indicating the invocation’s relative position within the subdivided patch, and outputs a single vertex and its associated data.

#### 8.9.1. Tessellation Evaluation Shader Execution

A tessellation evaluation shader is invoked at least once for each unique vertex generated by the tessellator. If the subpass includes multiple views in its view mask, the shader may be invoked separately for each view.

### 8.10. Geometry Shaders

The geometry shader operates on a group of vertices and their associated data assembled from a single input primitive, and emits zero or more output primitives and the group of vertices and their associated data required for each output primitive.

#### 8.10.1. Geometry Shader Execution

A geometry shader is invoked at least once for each primitive produced by the tessellation stages, or at least once for each primitive generated by primitive assembly when tessellation is not in use. A shader can request that the geometry shader runs multiple instances. A geometry shader is invoked at least once for each instance. If the subpass includes multiple views in its view mask, the shader may be invoked separately for each view.

### 8.11. Fragment Shaders

Fragment shaders are invoked as the result of rasterization in a graphics pipeline. Each fragment shader invocation operates on a single fragment and its associated data. With few exceptions, fragment shaders do not have access to any data associated with other fragments and are considered to execute in isolation of fragment shader invocations associated with other fragments.

#### 8.11.1. Fragment Shader Execution

For each fragment generated by rasterization, a fragment shader may be invoked. A fragment shader must not be invoked if the Early Per-Fragment Tests cause it to have no coverage. If the subpass includes multiple views in its view mask, the shader may be invoked separately for each view.

Furthermore, if it is determined that a fragment generated as the result of rasterizing a first primitive will have its outputs entirely overwritten by a fragment generated as the result of rasterizing a second primitive in the same subpass, and the fragment shader used for the fragment has no other side effects, then the fragment shader may not be executed for the fragment from the first primitive.

Relative ordering of execution of different fragment shader invocations is not defined.

For each fragment generated by a primitive, the number of times the fragment shader is invoked is implementation-dependent, but must obey the following constraints:

- Each covered sample is included in a single fragment shader invocation.

- When sample shading is not enabled, there is at least one fragment shader invocation.

- When sample shading is enabled, the minimum number of fragment shader invocations is as defined in Shading Rate Image and Sample Shading.

When there is more than one fragment shader invocation per fragment, the association of samples to invocations is implementation-dependent.

In addition to the conditions outlined above for the invocation of a fragment shader, a fragment shader invocation may be produced as a helper invocation. A helper invocation is a fragment shader invocation that is created solely for the purposes of evaluating derivatives for use in non-helper fragment shader invocations. Stores and atomics performed by helper invocations must not have any effect on memory, and values returned by atomic instructions in helper invocations are undefined.

If the render pass has a fragment density map attachment, more than one fragment shader invocation may be invoked for each covered sample. Stores and atomics performed by these additional invocations have the normal effect. Such additional invocations are only produced if `VkPhysicalDeviceFragmentDensityMapPropertiesEXT`::`fragmentDensityInvocations` is `VK_TRUE`.

| Note Implementations may generate these additional fragment shader invocations in order to make transitions between fragment areas with different fragment densities more smooth.

#### 8.11.2. Early Fragment Tests

An explicit control is provided to allow fragment shaders to enable early fragment tests. If the fragment shader specifies the `EarlyFragmentTests` `OpExecutionMode`, the per-fragment tests described in Early Fragment Test Mode are performed prior to fragment shader execution. Otherwise, they are performed after fragment shader execution.

If the fragment shader additionally specifies the `PostDepthCoverage` `OpExecutionMode`, the value of a variable decorated with the `SampleMask` built-in reflects the coverage after the early fragment tests. Otherwise, it reflects the coverage before the early fragment tests.

#### 8.11.3. Fragment Shader Interlock

In normal operation, it is possible for more than one fragment shader invocation to be executed simultaneously for the same pixel if there are overlapping primitives. If the fragmentShaderSampleInterlock, fragmentShaderPixelInterlock, or fragmentShaderShadingRateInterlock features are enabled, it is possible to define a critical section within the fragment shader that is guaranteed to not run simultaneously with another fragment shader invocation for the same sample(s) or pixel(s). It is also possible to control the relative ordering of execution of these critical sections across different fragment shader invovations.

If the `FragmentShaderSampleInterlockEXT`, `FragmentShaderPixelInterlockEXT`, or `FragmentShaderShadingRateInterlockEXT` capabilities are declared in the fragment shader, the `OpBeginInvocationInterlockEXT` and `OpEndInvocationInterlockEXT` instructions must be used to delimit a critical section of fragment shader code.

To ensure each invocation of the critical section is executed in primitive order, declare one of the `PixelInterlockOrderedEXT`, `SampleInterlockOrderedEXT`, or `ShadingRateInterlockOrderedEXT` execution modes. If the order of execution of each invocation of the critical section does not matter, declare one of the `PixelInterlockUnorderedEXT`, `SampleInterlockUnorderedEXT`, or `ShadingRateInterlockUnorderedEXT` execution modes.

The `PixelInterlockOrderedEXT` and `PixelInterlockUnorderedEXT` execution modes provide mutual exclusion in the critical section for any pair of fragments corresponding to the same pixel, or pixels if the fragment covers more than one pixel. With sample shading enabled, these execution modes are treated like `SampleInterlockOrderedEXT` or `SampleInterlockUnorderedEXT` respectively.

The `SampleInterlockOrderedEXT` and `SampleInterlockUnorderedEXT` execution modes only provide mutual exclusion for pairs of fragments that both cover at least one common sample in the same pixel; these are recommended for performance if shaders use per-sample data structures. If these execution modes are used in single-sample mode they are treated like `PixelInterlockOrderedEXT` or `PixelInterlockUnorderedEXT` respectively.

The `ShadingRateInterlockOrderedEXT` and `ShadingRateInterlockUnorderedEXT` execution modes provide mutual exclusion for pairs of fragments that both have at least one common sample in the same pixel, even if none of the common samples are covered by both fragments. With sample shading enabled, these execution modes are treated like `SampleInterlockOrderedEXT` or `SampleInterlockUnorderedEXT` respectively.

### 8.12. Compute Shaders

Compute shaders are invoked via vkCmdDispatch and vkCmdDispatchIndirect commands. In general, they have access to similar resources as shader stages executing as part of a graphics pipeline.

Compute workloads are formed from groups of work items called workgroups and processed by the compute shader in the current compute pipeline. A workgroup is a collection of shader invocations that execute the same shader, potentially in parallel. Compute shaders execute in global workgroups which are divided into a number of local workgroups with a size that can be set by assigning a value to the `LocalSize` execution mode or via an object decorated by the `WorkgroupSize` decoration. An invocation within a local workgroup can share data with other members of the local workgroup through shared variables and issue memory and control flow barriers to synchronize with other members of the local workgroup.

### 8.13. Interpolation Decorations

Interpolation decorations control the behavior of attribute interpolation in the fragment shader stage. Interpolation decorations can be applied to `Input` storage class variables in the fragment shader stage’s interface, and control the interpolation behavior of those variables.

Inputs that could be interpolated can be decorated by at most one of the following decorations:

- `Flat`: no interpolation

- `NoPerspective`: linear interpolation (for lines and polygons)

Fragment input variables decorated with neither `Flat` nor `NoPerspective` use perspective-correct interpolation (for lines and polygons).

The presence of and type of interpolation is controlled by the above interpolation decorations as well as the auxiliary decorations `Centroid` and `Sample`.

A variable decorated with `Flat` will not be interpolated. Instead, it will have the same value for every fragment within a triangle. This value will come from a single provoking vertex. A variable decorated with `Flat` can also be decorated with `Centroid` or `Sample`, which will mean the same thing as decorating it only as `Flat`.

For fragment shader input variables decorated with neither `Centroid` nor `Sample`, the assigned variable may be interpolated anywhere within the fragment and a single value may be assigned to each sample within the fragment.

If a fragment shader input is decorated with `Centroid`, a single value may be assigned to that variable for all samples in the fragment, but that value must be interpolated to a location that lies in both the fragment and in the primitive being rendered, including any of the fragment’s samples covered by the primitive. Because the location at which the variable is interpolated may be different in neighboring fragments, and derivatives may be computed by computing differences between neighboring fragments, derivatives of centroid-sampled inputs may be less accurate than those for non-centroid interpolated variables. If VkPipelineViewportShadingRateImageStateCreateInfoNV::`shadingRateImageEnable` is enabled, implementations may estimate derivatives using differencing without dividing by the distance between adjacent sample locations when the fragment size is larger than one pixel. The `PostDepthCoverage` execution mode does not affect the determination of the centroid location.

If a fragment shader input is decorated with `Sample`, a separate value must be assigned to that variable for each covered sample in the fragment, and that value must be sampled at the location of the individual sample. When `rasterizationSamples` is `VK_SAMPLE_COUNT_1_BIT`, the fragment center must be used for `Centroid`, `Sample`, and undecorated attribute interpolation.

Fragment shader inputs that are signed or unsigned integers, integer vectors, or any double-precision floating-point type must be decorated with `Flat`.

When the `VK_AMD_shader_explicit_vertex_parameter` device extension is enabled inputs can be also decorated with the `CustomInterpAMD` interpolation decoration, including fragment shader inputs that are signed or unsigned integers, integer vectors, or any double-precision floating-point type. Inputs decorated with `CustomInterpAMD` can only be accessed by the extended instruction `InterpolateAtVertexAMD` and allows accessing the value of the input for individual vertices of the primitive.

When the `fragmentShaderBarycentric` feature is enabled, inputs can be also decorated with the `PerVertexNV` interpolation decoration, including fragment shader inputs that are signed or unsigned integers, integer vectors, or any double-precision floating-point type. Inputs decorated with `PerVertexNV` can only be accessed using an extra array dimension, where the extra index identifies one of the vertices of the primitive that produced the fragment.

### 8.14. Ray Generation Shaders

A ray generation shader is similar to a compute shader. Its main purpose is to execute ray tracing queries using `OpTraceRayKHR` instructions and process the results.

#### 8.14.1. Ray Generation Shader Execution

One ray generation shader is executed per ray tracing dispatch. Its location in the shader binding table (see Shader Binding Table for details) is passed directly into `vkCmdTraceRaysKHR` using the `raygenShaderBindingTableBuffer` and `raygenShaderBindingOffset` parameters.

### 8.15. Intersection Shaders

Intersection shaders enable the implementation of arbitrary, application defined geometric primitives. An intersection shader for a primitive is executed whenever its axis-aligned bounding box is hit by a ray.

Like other ray tracing shader domains, an intersection shader operates on a single ray at a time. It also operates on a single primitive at a time. It is therefore the purpose of an intersection shader to compute the ray-primitive intersections and report them. To report an intersection, the shader calls the `OpReportIntersectionKHR` instruction.

An intersection shader communicates with any-hit and closest shaders by generating attribute values that they can read. Intersection shaders cannot read or modify the ray payload.

#### 8.15.1. Intersection Shader Execution

The order in which intersections are found along a ray, and therefore the order in which intersection shaders are executed, is unspecified.

The intersection shader of the closest AABB which intersects the ray is guaranteed to be executed at some point during traversal, unless the ray is forcibly terminated.

### 8.16. Any-Hit Shaders

The any-hit shader is executed after the intersection shader reports an intersection that lies within the current [tmin,tmax] of the ray. The main use of any-hit shaders is to programmatically decide whether or not an intersection will be accepted. The intersection will be accepted unless the shader calls the `OpIgnoreIntersectionKHR` instruction. Any-hit shaders have read-only access to the attributes generated by the corresponding intersection shader, and can read or modify the ray payload.

#### 8.16.1. Any-Hit Shader Execution

The order in which intersections are found along a ray, and therefore the order in which any-hit shaders are executed, is unspecified.

The any-hit shader of the closest hit is guaranteed to be executed at some point during traversal, unless the ray is forcibly terminated.

### 8.17. Closest Hit Shaders

Closest hit shaders have read-only access to the attributes generated by the corresponding intersection shader, and can read or modify the ray payload. They also have access to a number of system-generated values. Closest hit shaders can call `OpTraceRayKHR` to recursively trace rays.

#### 8.17.1. Closest Hit Shader Execution

Exactly one closest hit shader is executed when traversal is finished and an intersection has been found and accepted.

### 8.18. Miss Shaders

Miss shaders can access the ray payload and can trace new rays through the `OpTraceRayKHR` instruction, but cannot access attributes since they are not associated with an intersection.

#### 8.18.1. Miss Shader Execution

A miss shader is executed instead of a closest hit shader if no intersection was found during traversal.

### 8.19. Callable Shaders

Callable shaders can access a callable payload that works similarly to ray payloads to do subroutine work.

#### 8.19.1. Callable Shader Execution

A callable shader is executed by calling `OpExecuteCallableKHR` from an allowed shader stage.

### 8.20. Static Use

A SPIR-V module declares a global object in memory using the `OpVariable` instruction, which results in a pointer `x` to that object. A specific entry point in a SPIR-V module is said to statically use that object if that entry point’s call tree contains a function containing a memory instruction or image instruction with `x` as an `id` operand. See the “Memory Instructions” and “Image Instructions” subsections of section 3 “Binary Form” of the SPIR-V specification for the complete list of SPIR-V memory instructions.

Static use is not used to control the behavior of variables with `Input` and `Output` storage. The effects of those variables are applied based only on whether they are present in a shader entry point’s interface.

### 8.21. Scope

A scope describes a set of shader invocations, where each such set is a scope instance. Each invocation belongs to one or more scope instances, but belongs to no more than one scope instance for each scope.

The operations available between invocations in a given scope instance vary, with smaller scopes generally able to perform more operations, and with greater efficiency.

#### 8.21.1. Cross Device

All invocations executed in a Vulkan instance fall into a single cross device scope instance.

Whilst the `CrossDevice` scope is defined in SPIR-V, it is disallowed in Vulkan. API synchronization commands can be used to communicate between devices.

#### 8.21.2. Device

All invocations executed on a single device form a device scope instance.

If the `vulkanMemoryModel` and `vulkanMemoryModelDeviceScope` features are enabled, this scope is represented in SPIR-V by the `Device` `Scope`, which can be used as a `Memory` `Scope` for barrier and atomic operations.

There is no method to synchronize the execution of these invocations within SPIR-V, and this can only be done with API synchronization primitives.

Invocations executing on different devices in a device group operate in separate device scope instances.

#### 8.21.3. Queue Family

Invocations executed by queues in a given queue family form a queue family scope instance.

This scope is identified in SPIR-V as the `QueueFamily` `Scope` if the `vulkanMemoryModel` feature is enabled, or if not, the `Device` `Scope`, which can be used as a `Memory` `Scope` for barrier and atomic operations.

There is no method to synchronize the execution of these invocations within SPIR-V, and this can only be done with API synchronization primitives.

Each invocation in a queue family scope instance must be in the same device scope instance.

#### 8.21.4. Command

Any shader invocations executed as the result of a single command such as vkCmdDispatch or vkCmdDraw form a command scope instance. For indirect drawing commands with `drawCount` greater than one, invocations from separate draws are in separate command scope instances. For ray tracing shaders, an invocation group is an implementation-dependent subset of the set of shader invocations of a given shader stage which are produced by a single trace rays command.

There is no specific `Scope` for communication across invocations in a command scope instance. As this has a clear boundary at the API level, coordination here can be performed in the API, rather than in SPIR-V.

Each invocation in a command scope instance must be in the same queue-family scope instance.

For shaders without defined workgroups, this set of invocations forms an invocation group as defined in the SPIR-V specification (see the subsection “Control Flow” of section 2 of the SPIR-V 1.00 Revision 4 specification).

#### 8.21.5. Primitive

Any fragment shader invocations executed as the result of rasterization of a single primitive form a primitive scope instance.

There is no specific `Scope` for communication across invocations in a primitive scope instance.

Any generated helper invocations are included in this scope instance.

Each invocation in a primitive scope instance must be in the same command scope instance.

Any input variables decorated with `Flat` are uniform within a primitive scope instance.

#### 8.21.6. Shader Call

Any shader-call-related invocations that are executed in one or more ray tracing execution models form a shader call scope instance.

The `ShaderCallKHR` `Scope` can be used as `Memory` `Scope` for barrier and atomic operations.

Each invocation in a shader call scope instance must be in the same queue family scope instance.

#### 8.21.7. Workgroup

A local workgroup is a set of invocations that can synchronize and share data with each other using memory in the `Workgroup` storage class.

The `Workgroup` `Scope` can be used as both an `Execution` `Scope` and `Memory` `Scope` for barrier and atomic operations.

Each invocation in a local workgroup must be in the same command scope instance.

Only task, mesh, and compute shaders have defined workgroups - other shader types cannot use workgroup functionality. For shaders that have defined workgroups, this set of invocations forms an invocation group as defined in the SPIR-V specification (see the subsection “Control Flow” of section 2 of the SPIR-V 1.00 Revision 4 specification).

#### 8.21.8. Subgroup

A subgroup (see the subsection “Control Flow” of section 2 of the SPIR-V 1.3 Revision 1 specification) is a set of invocations that can synchronize and share data with each other efficiently.

The `Subgroup` `Scope` can be used as both an `Execution` `Scope` and `Memory` `Scope` for barrier and atomic operations. Other subgroup features allow the use of group operations with subgroup scope.

For shaders that have defined workgroups, each invocation in a subgroup must be in the same local workgroup.

In other shader stages, each invocation in a subgroup must be in the same device scope instance.

Only shader stages that support subgroup operations have defined subgroups.

#### 8.21.9. Quad

A quad scope instance is formed of four shader invocations.

In a fragment shader, each invocation in a quad scope instance is formed of invocations in neighboring framebuffer locations (xi, yi), where:

- i is the index of the invocation within the scope instance.

- x0 = x1 - 1 = x2 = x3 - 1

- y0 = y1 = y2 - 1 = y3 - 1

- Each invocation has the same layer and sample indices.

In a compute shader, if the `DerivativeGroupQuadsNV` execution mode is specified, each invocation in a quad scope instance is formed of invocations with adjacent local invocation IDs (xi, yi), where:

- i is the index of the invocation within the quad scope instance.

- x0 = x1 - 1 = x2 = x3 - 1

- y0 = y1 = y2 - 1 = y3 - 1

- x0 and y0 are integer multiples of 2.

- Each invocation has the same z coordinate.

In a compute shader, if the `DerivativeGroupLinearNV` execution mode is specified, each invocation in a quad scope instance is formed of invocations with adjacent local invocation indices (li), where:

- i is the index of the invocation within the quad scope instance.

- l0 = l1 - 1 = l2 - 2 = l3 - 3

- l0 is an integer multiple of 4.

In all shaders, each invocation in a quad scope instance is formed of invocations in adjacent subgroup invocation indices (si), where:

- i is the index of the invocation within the quad scope instance.

- s0 = s1 - 1 = s2 - 2 = s3 - 3

- s0 is an integer multiple of 4.

Each invocation in a quad scope instance must be in the same subgroup.

Fragment and compute shaders have defined quad scope instances. If the `quadOperationsInAllStages` limit is supported, any shader stages that support subgroup operations also have defined quad scope instances.

#### 8.21.10. Fragment Interlock

A fragment interlock scope instance is formed of fragment shader invocations based on their framebuffer locations (x,y,layer,sample), executed by commands inside a single subpass.

The specific set of invocations included varies based on the execution mode as follows:

- If the `SampleInterlockOrderedEXT` or `SampleInterlockUnorderedEXT` execution modes are used, only invocations with identical framebuffer locations (x,y,layer,sample) are included.

- If the `PixelInterlockOrderedEXT` or `PixelInterlockUnorderedEXT` execution modes are used, fragments with different sample ids are also included.

- If the `ShadingRateInterlockOrderedEXT` or `ShadingRateInterlockUnorderedEXT` execution modes are used, fragments from neighbouring framebuffer locations are also included, as determined by the shading rate.

Only fragment shaders with one of the above execution modes have defined fragment interlock scope instances.

There is no specific `Scope` value for communication across invocations in a fragment interlock scope instance. However, this is implicitly used as a memory scope by `OpBeginInvocationInterlockEXT` and `OpEndInvocationInterlockEXT`.

Each invocation in a fragment interlock scope instance must be in the same queue family scope instance.

#### 8.21.11. Invocation

The smallest scope is a single invocation; this is represented by the `Invocation` `Scope` in SPIR-V.

Fragment shader invocations must be in a [shaders-scope-primitive primitive scope instance].

Invocations in fragment shaders that have a defined fragment interlock scope must be in a fragment interlock scope instance.

Invocations in shaders that have defined workgroups must be in a local workgroup.

Invocations in shaders that have a defined subgroup scope must be in a subgroup.

Invocations in shaders that have a defined quad scope must be in a quad scope instance.

All invocations in all stages must be in a command scope instance.

### 8.22. Group Operations

Group operations are executed by multiple invocations within a scope instance; with each invocation involved in calculating the result. This provides a mechanism for efficient communication between invocations in a particular scope instance.

Group operations all take a `Scope` defining the desired scope instance to operate within. Only the `Subgroup` scope can be used for these operations; the `subgroupSupportedOperations` limit defines which types of operation can be used.

#### 8.22.1. Basic Group Operations

Basic group operations include the use of `OpGroupNonUniformElect`, `OpControlBarrier`, `OpMemoryBarrier`, and atomic operations.

`OpGroupNonUniformElect` can be used to choose a single invocation to perform a task for the whole group. Only the invocation with the lowest id in the group will return `true`.

The Memory Model appendix defines the operation of barriers and atomics.

#### 8.22.2. Vote Group Operations

The vote group operations allow invocations within a group to compare values across a group. The types of votes enabled are:

- Do all active group invocations agree that an expression is true?

- Do any active group invocations evaluate an expression to true?

- Do all active group invocations have the same value of an expression?

| Note These operations are useful in combination with control flow in that they allow for developers to check whether conditions match across the group and choose potentially faster code-paths in these cases.

#### 8.22.3. Arithmetic Group Operations

The arithmetic group operations allow invocations to perform scans and reductions across a group. The operators supported are add, mul, min, max, and, or, xor.

For reductions, every invocation in a group will obtain the cumulative result of these operators applied to all values in the group. For exclusive scans, each invocation in a group will obtain the cumulative result of these operators applied to all values in invocations with a lower index in the group. Inclusive scans are identical to exclusive scans, except the cumulative result includes the operator applied to the value in the current invocation.

The order in which these operators are applied is implementation-dependent.

#### 8.22.4. Ballot Group Operations

The ballot group operations allow invocations to perform more complex votes across the group. The ballot functionality allows all invocations within a group to provide a boolean value and get as a result what each invocation provided as their boolean value. The broadcast functionality allows values to be broadcast from an invocation to all other invocations within the group.

#### 8.22.5. Shuffle Group Operations

The shuffle group operations allow invocations to read values from other invocations within a group.

#### 8.22.6. Shuffle Relative Group Operations

The shuffle relative group operations allow invocations to read values from other invocations within the group relative to the current invocation in the group. The relative operations supported allow data to be shifted up and down through the invocations within a group.

#### 8.22.7. Clustered Group Operations

The clustered group operations allow invocations to perform an operation among partitions of a group, such that the operation is only performed within the group invocations within a partition. The partitions for clustered group operations are consecutive power-of-two size groups of invocations and the cluster size must be known at pipeline creation time. The operations supported are add, mul, min, max, and, or, xor.

### 8.23. Quad Group Operations

Quad group operations (`OpGroupNonUniformQuad`*) are a specialized type of group operations that only operate on quad scope instances. Whilst these instructions do include a `Scope` parameter, this scope is always overridden; only the quad scope instance is included in its execution scope.

Fragment shaders that statically execute quad group operations must launch sufficient invocations to ensure their correct operation; additional helper invocations are launched for framebuffer locations not covered by rasterized fragments if necessary.

The index used to select participating invocations is i, as described for a quad scope instance. For `OpGroupNonUniformQuadBroadcast` this value is equal to `Index`. For `OpGroupNonUniformQuadSwap`, it’s equal to the implicit `Index` used by each participating invocation.

### 8.24. Derivative Operations

Derivative operations calculate the partial derivative for an expression P as a function of an invocation’s x and y coordinates.

Derivative operations operate on a set of invocations known as a derivative group as defined in the SPIR-V specification (see the subsection “Control Flow” of section 2 of the SPIR-V 1.00 Revision 4 specification). A derivative group is equivalent to the local workgroup for a compute shader invocation, or the primitive scope instance for a fragment shader invocation.

Derivatives are calculated assuming that P is piecewise linear and continuous within the derivative group. All dynamic instances of explicit derivative instructions (`OpDPdx`*, `OpDPdy`*, and `OpFwidth`*) must be executed in control flow that is uniform within a derivative group. For other derivative operations, results are undefined if a dynamic instance is executed in control flow is not uniform within the derivative group.

Fragment shaders that statically execute derivative operations must launch sufficient invocations to ensure their correct operation; additional helper invocations are launched for framebuffer locations not covered by rasterized fragments if necessary.

| Note In a compute shader, it is the application’s responsibility to ensure that sufficient invocations are launched.

Derivative operations calculate their results as the difference between the result of P across invocations in the quad. For fine derivative operations (`OpDPdxFine` and `OpDPdyFine`), the values of DPdx(Pi) are calculated as

  DPdx(P0) = DPdx(P1) = P1 - P0

  DPdx(P2) = DPdx(P3) = P3 - P2

and the values of DPdy(Pi) are calculated as

  DPdy(P0) = DPdy(P2) = P2 - P0

  DPdy(P1) = DPdy(P3) = P3 - P1

where i is the index of each invocation as described in Quad.

Coarse derivative operations (`OpDPdxCoarse` and `OpDPdyCoarse`), calculate their results in roughly the same manner, but may only calculate two values instead of four (one for each of DPdx and DPdy), reusing the same result no matter the originating invocation. If an implementation does this, it should use the fine derivative calculations described for P0.

The results for `OpDPdx` and `OpDPdy` may be calculated as either fine or coarse derivatives, with implementations favouring the most efficient approach. Implementations must choose coarse or fine consistently between the two.

Executing `OpFwidthFine`, `OpFwidthCoarse`, or `OpFwidth` is equivalent to executing the corresponding `OpDPdx`* and `OpDPdy`* instructions, taking the absolute value of the results, and summing them.

Executing a `OpImage`*Sample*ImplicitLod instruction is equivalent to executing `OpDPdx`(`Coordinate`) and `OpDPdy`(`Coordinate`), and passing the results as the `Grad` operands `dx` and `dy`.

| Note It is expected that using the `ImplicitLod` variants of sampling functions will be substantially more efficient than using the `ExplicitLod` variants with explicitly generated derivatives.

### 8.25. Helper Invocations

When performing derivative or quad group operations in a fragment shader, additional invocations may be spawned in order to ensure correct results. These additional invocations are known as helper invocations and can be identified by a non-zero value in the `HelperInvocation` built-in. Stores and atomics performed by helper invocations must not have any effect on memory, and values returned by atomic instructions in helper invocations are undefined.

Helper invocations may become inactive at any time for any reason, with one exception. If a helper invocation would be active if it were not a helper invocation, it must be active for derivative and quad group operations.

Helper invocations may become permanently inactive if all invocations in a quad scope instance become helper invocations.

### 8.26. Cooperative Matrices

A cooperative matrix type is a SPIR-V type where the storage for and computations performed on the matrix are spread across the invocations in a scope instance. These types give the implementation freedom in how to optimize matrix multiplies.

SPIR-V defines the types and instructions, but does not specify rules about what sizes/combinations are valid, and it is expected that different implementations may support different sizes.

To enumerate the supported cooperative matrix types and operations, call:

    VkResult vkGetPhysicalDeviceCooperativeMatrixPropertiesNV(
        VkPhysicalDevice                            physicalDevice,
        uint32_t*                                   pPropertyCount,
        VkCooperativeMatrixPropertiesNV*            pProperties);

- `physicalDevice` is the physical device.

- `pPropertyCount` is a pointer to an integer related to the number of cooperative matrix properties available or queried.

- `pProperties` is either `NULL` or a pointer to an array of VkCooperativeMatrixPropertiesNV structures.

If `pProperties` is `NULL`, then the number of cooperative matrix properties available is returned in `pPropertyCount`. Otherwise, `pPropertyCount` must point to a variable set by the user to the number of elements in the `pProperties` array, and on return the variable is overwritten with the number of structures actually written to `pProperties`. If `pPropertyCount` is less than the number of cooperative matrix properties available, at most `pPropertyCount` structures will be written. If `pPropertyCount` is smaller than the number of cooperative matrix properties available, `VK_INCOMPLETE` will be returned instead of `VK_SUCCESS`, to indicate that not all the available cooperative matrix properties were returned.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pPropertyCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pPropertyCount` is not `0`, and `pProperties` is not `NULL`, `pProperties` must be a valid pointer to an array of `pPropertyCount` VkCooperativeMatrixPropertiesNV structures

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

Each `VkCooperativeMatrixPropertiesNV` structure describes a single supported combination of types for a matrix multiply/add operation (`OpCooperativeMatrixMulAddNV`). The multiply can be described in terms of the following variables and types (in SPIR-V pseudocode):

        %A is of type OpTypeCooperativeMatrixNV %AType %scope %MSize %KSize
        %B is of type OpTypeCooperativeMatrixNV %BType %scope %KSize %NSize
        %C is of type OpTypeCooperativeMatrixNV %CType %scope %MSize %NSize
        %D is of type OpTypeCooperativeMatrixNV %DType %scope %MSize %NSize

        %D = %A * %B + %C // using OpCooperativeMatrixMulAddNV

A matrix multiply with these dimensions is known as an MxNxK matrix multiply.

The `VkCooperativeMatrixPropertiesNV` structure is defined as:

    typedef struct VkCooperativeMatrixPropertiesNV {
        VkStructureType      sType;
        void*                pNext;
        uint32_t             MSize;
        uint32_t             NSize;
        uint32_t             KSize;
        VkComponentTypeNV    AType;
        VkComponentTypeNV    BType;
        VkComponentTypeNV    CType;
        VkComponentTypeNV    DType;
        VkScopeNV            scope;
    } VkCooperativeMatrixPropertiesNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `MSize` is the number of rows in matrices A, C, and D.

- `KSize` is the number of columns in matrix A and rows in matrix B.

- `NSize` is the number of columns in matrices B, C, D.

- `AType` is the component type of matrix A, of type VkComponentTypeNV.

- `BType` is the component type of matrix B, of type VkComponentTypeNV.

- `CType` is the component type of matrix C, of type VkComponentTypeNV.

- `DType` is the component type of matrix D, of type VkComponentTypeNV.

- `scope` is the scope of all the matrix types, of type VkScopeNV.

If some types are preferred over other types (e.g. for performance), they should appear earlier in the list enumerated by vkGetPhysicalDeviceCooperativeMatrixPropertiesNV.

At least one entry in the list must have power of two values for all of `MSize`, `KSize`, and `NSize`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_COOPERATIVE_MATRIX_PROPERTIES_NV`

- `pNext` must be `NULL`

- `AType` must be a valid VkComponentTypeNV value

- `BType` must be a valid VkComponentTypeNV value

- `CType` must be a valid VkComponentTypeNV value

- `DType` must be a valid VkComponentTypeNV value

- `scope` must be a valid VkScopeNV value

Possible values for VkScopeNV include:

    typedef enum VkScopeNV {
        VK_SCOPE_DEVICE_NV = 1,
        VK_SCOPE_WORKGROUP_NV = 2,
        VK_SCOPE_SUBGROUP_NV = 3,
        VK_SCOPE_QUEUE_FAMILY_NV = 5,
        VK_SCOPE_MAX_ENUM_NV = 0x7FFFFFFF
    } VkScopeNV;

- `VK_SCOPE_DEVICE_NV` corresponds to SPIR-V `Device` scope.

- `VK_SCOPE_WORKGROUP_NV` corresponds to SPIR-V `Workgroup` scope.

- `VK_SCOPE_SUBGROUP_NV` corresponds to SPIR-V `Subgroup` scope.

- `VK_SCOPE_QUEUE_FAMILY_NV` corresponds to SPIR-V `QueueFamily` scope.

All enum values match the corresponding SPIR-V value.

Possible values for VkComponentTypeNV include:

    typedef enum VkComponentTypeNV {
        VK_COMPONENT_TYPE_FLOAT16_NV = 0,
        VK_COMPONENT_TYPE_FLOAT32_NV = 1,
        VK_COMPONENT_TYPE_FLOAT64_NV = 2,
        VK_COMPONENT_TYPE_SINT8_NV = 3,
        VK_COMPONENT_TYPE_SINT16_NV = 4,
        VK_COMPONENT_TYPE_SINT32_NV = 5,
        VK_COMPONENT_TYPE_SINT64_NV = 6,
        VK_COMPONENT_TYPE_UINT8_NV = 7,
        VK_COMPONENT_TYPE_UINT16_NV = 8,
        VK_COMPONENT_TYPE_UINT32_NV = 9,
        VK_COMPONENT_TYPE_UINT64_NV = 10,
        VK_COMPONENT_TYPE_MAX_ENUM_NV = 0x7FFFFFFF
    } VkComponentTypeNV;

- `VK_COMPONENT_TYPE_FLOAT16_NV` corresponds to SPIR-V `OpTypeFloat` 16.

- `VK_COMPONENT_TYPE_FLOAT32_NV` corresponds to SPIR-V `OpTypeFloat` 32.

- `VK_COMPONENT_TYPE_FLOAT64_NV` corresponds to SPIR-V `OpTypeFloat` 64.

- `VK_COMPONENT_TYPE_SINT8_NV` corresponds to SPIR-V `OpTypeInt` 8 1.

- `VK_COMPONENT_TYPE_SINT16_NV` corresponds to SPIR-V `OpTypeInt` 16 1.

- `VK_COMPONENT_TYPE_SINT32_NV` corresponds to SPIR-V `OpTypeInt` 32 1.

- `VK_COMPONENT_TYPE_SINT64_NV` corresponds to SPIR-V `OpTypeInt` 64 1.

- `VK_COMPONENT_TYPE_UINT8_NV` corresponds to SPIR-V `OpTypeInt` 8 0.

- `VK_COMPONENT_TYPE_UINT16_NV` corresponds to SPIR-V `OpTypeInt` 16 0.

- `VK_COMPONENT_TYPE_UINT32_NV` corresponds to SPIR-V `OpTypeInt` 32 0.

- `VK_COMPONENT_TYPE_UINT64_NV` corresponds to SPIR-V `OpTypeInt` 64 0.

### 8.27. Validation Cache

Validation cache objects allow the result of internal validation to be reused, both within a single application run and between multiple runs. Reuse within a single run is achieved by passing the same validation cache object when creating supported Vulkan objects. Reuse across runs of an application is achieved by retrieving validation cache contents in one run of an application, saving the contents, and using them to preinitialize a validation cache on a subsequent run. The contents of the validation cache objects are managed by the validation layers. Applications can manage the host memory consumed by a validation cache object and control the amount of data retrieved from a validation cache object.

Validation cache objects are represented by `VkValidationCacheEXT` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkValidationCacheEXT)

To create validation cache objects, call:

    VkResult vkCreateValidationCacheEXT(
        VkDevice                                    device,
        const VkValidationCacheCreateInfoEXT*       pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkValidationCacheEXT*                       pValidationCache);

- `device` is the logical device that creates the validation cache object.

- `pCreateInfo` is a pointer to a VkValidationCacheCreateInfoEXT structure containing the initial parameters for the validation cache object.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pValidationCache` is a pointer to a VkValidationCacheEXT handle in which the resulting validation cache object is returned.

| Note Applications can track and manage the total host memory size of a validation cache object using the `pAllocator`. Applications can limit the amount of data retrieved from a validation cache object in `vkGetValidationCacheDataEXT`. Implementations should not internally limit the total number of entries added to a validation cache object or the total host memory consumed.

Once created, a validation cache can be passed to the `vkCreateShaderModule` command by adding this object to the `VkShaderModuleCreateInfo` structure’s `pNext` chain. If a `VkShaderModuleValidationCacheCreateInfoEXT` object is included in the `VkShaderModuleCreateInfo`::`pNext` chain, and its `validationCache` field is not VK_NULL_HANDLE, the implementation will query it for possible reuse opportunities and update it with new content. The use of the validation cache object in these commands is internally synchronized, and the same validation cache object can be used in multiple threads simultaneously.

| Note Implementations should make every effort to limit any critical sections to the actual accesses to the cache, which is expected to be significantly shorter than the duration of the `vkCreateShaderModule` command.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkValidationCacheCreateInfoEXT structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pValidationCache` must be a valid pointer to a VkValidationCacheEXT handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

The `VkValidationCacheCreateInfoEXT` structure is defined as:

    typedef struct VkValidationCacheCreateInfoEXT {
        VkStructureType                    sType;
        const void*                        pNext;
        VkValidationCacheCreateFlagsEXT    flags;
        size_t                             initialDataSize;
        const void*                        pInitialData;
    } VkValidationCacheCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `initialDataSize` is the number of bytes in `pInitialData`. If `initialDataSize` is zero, the validation cache will initially be empty.

- `pInitialData` is a pointer to previously retrieved validation cache data. If the validation cache data is incompatible (as defined below) with the device, the validation cache will be initially empty. If `initialDataSize` is zero, `pInitialData` is ignored.

Valid Usage

- If `initialDataSize` is not `0`, it must be equal to the size of `pInitialData`, as returned by `vkGetValidationCacheDataEXT` when `pInitialData` was originally retrieved

- If `initialDataSize` is not `0`, `pInitialData` must have been retrieved from a previous call to `vkGetValidationCacheDataEXT`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_VALIDATION_CACHE_CREATE_INFO_EXT`

- `pNext` must be `NULL`

- `flags` must be `0`

- If `initialDataSize` is not `0`, `pInitialData` must be a valid pointer to an array of `initialDataSize` bytes

    typedef VkFlags VkValidationCacheCreateFlagsEXT;

`VkValidationCacheCreateFlagsEXT` is a bitmask type for setting a mask, but is currently reserved for future use.

Validation cache objects can be merged using the command:

    VkResult vkMergeValidationCachesEXT(
        VkDevice                                    device,
        VkValidationCacheEXT                        dstCache,
        uint32_t                                    srcCacheCount,
        const VkValidationCacheEXT*                 pSrcCaches);

- `device` is the logical device that owns the validation cache objects.

- `dstCache` is the handle of the validation cache to merge results into.

- `srcCacheCount` is the length of the `pSrcCaches` array.

- `pSrcCaches` is a pointer to an array of validation cache handles, which will be merged into `dstCache`. The previous contents of `dstCache` are included after the merge.

| Note The details of the merge operation are implementation dependent, but implementations should merge the contents of the specified validation caches and prune duplicate entries.

Valid Usage

- `dstCache` must not appear in the list of source caches

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `dstCache` must be a valid VkValidationCacheEXT handle

- `pSrcCaches` must be a valid pointer to an array of `srcCacheCount` valid VkValidationCacheEXT handles

- `srcCacheCount` must be greater than `0`

- `dstCache` must have been created, allocated, or retrieved from `device`

- Each element of `pSrcCaches` must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `dstCache` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

Data can be retrieved from a validation cache object using the command:

    VkResult vkGetValidationCacheDataEXT(
        VkDevice                                    device,
        VkValidationCacheEXT                        validationCache,
        size_t*                                     pDataSize,
        void*                                       pData);

- `device` is the logical device that owns the validation cache.

- `validationCache` is the validation cache to retrieve data from.

- `pDataSize` is a pointer to a value related to the amount of data in the validation cache, as described below.

- `pData` is either `NULL` or a pointer to a buffer.

If `pData` is `NULL`, then the maximum size of the data that can be retrieved from the validation cache, in bytes, is returned in `pDataSize`. Otherwise, `pDataSize` must point to a variable set by the user to the size of the buffer, in bytes, pointed to by `pData`, and on return the variable is overwritten with the amount of data actually written to `pData`.

If `pDataSize` is less than the maximum size that can be retrieved by the validation cache, at most `pDataSize` bytes will be written to `pData`, and `vkGetValidationCacheDataEXT` will return `VK_INCOMPLETE`. Any data written to `pData` is valid and can be provided as the `pInitialData` member of the `VkValidationCacheCreateInfoEXT` structure passed to `vkCreateValidationCacheEXT`.

Two calls to `vkGetValidationCacheDataEXT` with the same parameters must retrieve the same data unless a command that modifies the contents of the cache is called between them.

Applications can store the data retrieved from the validation cache, and use these data, possibly in a future run of the application, to populate new validation cache objects. The results of validation, however, may depend on the vendor ID, device ID, driver version, and other details of the device. To enable applications to detect when previously retrieved data is incompatible with the device, the initial bytes written to `pData` must be a header consisting of the following members:

Table 11. Layout for validation cache header version `VK_VALIDATION_CACHE_HEADER_VERSION_ONE_EXT`
Offset | Size | Meaning
--- | --- | ---
0 | 4 | length in bytes of the entire validation cache header written as a stream of bytes, with the least significant byte first
4 | 4 | a VkValidationCacheHeaderVersionEXT value written as a stream of bytes, with the least significant byte first
8 | `VK_UUID_SIZE` | a layer commit ID expressed as a UUID, which uniquely identifies the version of the validation layers used to generate these validation results

The first four bytes encode the length of the entire validation cache header, in bytes. This value includes all fields in the header including the validation cache version field and the size of the length field.

The next four bytes encode the validation cache version, as described for VkValidationCacheHeaderVersionEXT. A consumer of the validation cache should use the cache version to interpret the remainder of the cache header.

If `pDataSize` is less than what is necessary to store this header, nothing will be written to `pData` and zero will be written to `pDataSize`.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `validationCache` must be a valid VkValidationCacheEXT handle

- `pDataSize` must be a valid pointer to a `size_t` value

- If the value referenced by `pDataSize` is not `0`, and `pData` is not `NULL`, `pData` must be a valid pointer to an array of `pDataSize` bytes

- `validationCache` must have been created, allocated, or retrieved from `device`

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

Possible values of the second group of four bytes in the header returned by vkGetValidationCacheDataEXT, encoding the validation cache version, are:

    typedef enum VkValidationCacheHeaderVersionEXT {
        VK_VALIDATION_CACHE_HEADER_VERSION_ONE_EXT = 1,
        VK_VALIDATION_CACHE_HEADER_VERSION_MAX_ENUM_EXT = 0x7FFFFFFF
    } VkValidationCacheHeaderVersionEXT;

- `VK_VALIDATION_CACHE_HEADER_VERSION_ONE_EXT` specifies version one of the validation cache.

To destroy a validation cache, call:

    void vkDestroyValidationCacheEXT(
        VkDevice                                    device,
        VkValidationCacheEXT                        validationCache,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that destroys the validation cache object.

- `validationCache` is the handle of the validation cache to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage

- If `VkAllocationCallbacks` were provided when `validationCache` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `validationCache` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `validationCache` is not VK_NULL_HANDLE, `validationCache` must be a valid VkValidationCacheEXT handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- If `validationCache` is a valid handle, it must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `validationCache` must be externally synchronized

## 9. Pipelines

The following figure shows a block diagram of the Vulkan pipelines. Some Vulkan commands specify geometric objects to be drawn or computational work to be performed, while others specify state controlling how objects are handled by the various pipeline stages, or control data transfer between memory organized as images and buffers. Commands are effectively sent through a processing pipeline, either a graphics pipeline, a ray tracing pipeline, or a compute pipeline.

The graphics pipeline can be operated in two modes, as either primitive shading or mesh shading pipeline.

Primitive Shading

The first stage of the graphics pipeline (Input Assembler) assembles vertices to form geometric primitives such as points, lines, and triangles, based on a requested primitive topology. In the next stage (Vertex Shader) vertices can be transformed, computing positions and attributes for each vertex. If tessellation and/or geometry shaders are supported, they can then generate multiple primitives from a single input primitive, possibly changing the primitive topology or generating additional attribute data in the process.

Mesh Shading

When using the mesh shading pipeline input primitives are not assembled implicitly, but explicitly through the (Mesh Shader). The work on the mesh pipeline is initiated by the application drawing a set of mesh tasks.

If an optional (Task Shader) is active, each task triggers the execution of a task shader workgroup that will generate a new set of tasks upon completion. Each of these spawned tasks, or each of the original dispatched tasks if no task shader is present, triggers the execution of a mesh shader workgroup that produces an output mesh with a variable-sized number of primitives assembled from vertices stored in the output mesh.

Common

The final resulting primitives are clipped to a clip volume in preparation for the next stage, Rasterization. The rasterizer produces a series of framebuffer addresses and values using a two-dimensional description of a point, line segment, or triangle. Each fragment so produced is fed to the next stage (Fragment Shader) that performs operations on individual fragments before they finally alter the framebuffer. These operations include conditional updates into the framebuffer based on incoming and previously stored depth values (to effect depth buffering), blending of incoming fragment colors with stored colors, as well as masking, stenciling, and other logical operations on fragment values.

Framebuffer operations read and write the color and depth/stencil attachments of the framebuffer for a given subpass of a render pass instance. The attachments can be used as input attachments in the fragment shader in a later subpass of the same render pass.

The compute pipeline is a separate pipeline from the graphics pipeline, which operates on one-, two-, or three-dimensional workgroups which can read from and write to buffer and image memory.

This ordering is meant only as a tool for describing Vulkan, not as a strict rule of how Vulkan is implemented, and we present it only as a means to organize the various operations of the pipelines. Actual ordering guarantees between pipeline stages are explained in detail in the synchronization chapter.

Figure 2. Block diagram of the Vulkan pipeline

Each pipeline is controlled by a monolithic object created from a description of all of the shader stages and any relevant fixed-function stages. Linking the whole pipeline together allows the optimization of shaders based on their input/outputs and eliminates expensive draw time state validation.

A pipeline object is bound to the current state using vkCmdBindPipeline. Any pipeline object state that is specified as dynamic is not applied to the current state when the pipeline object is bound, but is instead set by dynamic state setting commands.

No state, including dynamic state, is inherited from one command buffer to another.

Compute, ray tracing, and graphics pipelines are each represented by `VkPipeline` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkPipeline)

### 9.1. Compute Pipelines

Compute pipelines consist of a single static compute shader stage and the pipeline layout.

The compute pipeline represents a compute shader and is created by calling `vkCreateComputePipelines` with `module` and `pName` selecting an entry point from a shader module, where that entry point defines a valid compute shader, in the `VkPipelineShaderStageCreateInfo` structure contained within the `VkComputePipelineCreateInfo` structure.

To create compute pipelines, call:

    VkResult vkCreateComputePipelines(
        VkDevice                                    device,
        VkPipelineCache                             pipelineCache,
        uint32_t                                    createInfoCount,
        const VkComputePipelineCreateInfo*          pCreateInfos,
        const VkAllocationCallbacks*                pAllocator,
        VkPipeline*                                 pPipelines);

- `device` is the logical device that creates the compute pipelines.

- `pipelineCache` is either VK_NULL_HANDLE, indicating that pipeline caching is disabled; or the handle of a valid pipeline cache object, in which case use of that cache is enabled for the duration of the command.

- `createInfoCount` is the length of the `pCreateInfos` and `pPipelines` arrays.

- `pCreateInfos` is a pointer to an array of VkComputePipelineCreateInfo structures.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pPipelines` is a pointer to an array of VkPipeline handles in which the resulting compute pipeline objects are returned.

  | editing-note TODO (Jon) - Should we say something like “the i’th element of the `pPipelines` array is created based on the corresponding element of the `pCreateInfos` array”? Also for vkCreateGraphicsPipelines below.

Valid Usage

- If the `flags` member of any element of `pCreateInfos` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, and the `basePipelineIndex` member of that same element is not `-1`, `basePipelineIndex` must be less than the index into `pCreateInfos` that corresponds to that element

- If the `flags` member of any element of `pCreateInfos` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, the base pipeline must have been created with the `VK_PIPELINE_CREATE_ALLOW_DERIVATIVES_BIT` flag set

- If `pipelineCache` was created with `VK_PIPELINE_CACHE_CREATE_EXTERNALLY_SYNCHRONIZED_BIT_EXT`, host access to `pipelineCache` must be externally synchronized.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `pipelineCache` is not VK_NULL_HANDLE, `pipelineCache` must be a valid VkPipelineCache handle

- `pCreateInfos` must be a valid pointer to an array of `createInfoCount` valid VkComputePipelineCreateInfo structures

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pPipelines` must be a valid pointer to an array of `createInfoCount` VkPipeline handles

- `createInfoCount` must be greater than `0`

- If `pipelineCache` is a valid handle, it must have been created, allocated, or retrieved from `device`

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_INVALID_SHADER_NV`

The `VkComputePipelineCreateInfo` structure is defined as:

    typedef struct VkComputePipelineCreateInfo {
        VkStructureType                    sType;
        const void*                        pNext;
        VkPipelineCreateFlags              flags;
        VkPipelineShaderStageCreateInfo    stage;
        VkPipelineLayout                   layout;
        VkPipeline                         basePipelineHandle;
        int32_t                            basePipelineIndex;
    } VkComputePipelineCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkPipelineCreateFlagBits specifying how the pipeline will be generated.

- `stage` is a VkPipelineShaderStageCreateInfo structure describing the compute shader.

- `layout` is the description of binding locations used by both the pipeline and descriptor sets used with the pipeline.

- `basePipelineHandle` is a pipeline to derive from

- `basePipelineIndex` is an index into the `pCreateInfos` parameter to use as a pipeline to derive from

The parameters `basePipelineHandle` and `basePipelineIndex` are described in more detail in Pipeline Derivatives.

Valid Usage

- If `flags` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, and `basePipelineIndex` is -1, `basePipelineHandle` must be a valid handle to a compute `VkPipeline`

- If `flags` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, and `basePipelineHandle` is VK_NULL_HANDLE, `basePipelineIndex` must be a valid index into the calling command’s `pCreateInfos` parameter

- If `flags` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, and `basePipelineIndex` is not -1, `basePipelineHandle` must be VK_NULL_HANDLE

- If `flags` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, and `basePipelineHandle` is not VK_NULL_HANDLE, `basePipelineIndex` must be -1

- The `stage` member of `stage` must be `VK_SHADER_STAGE_COMPUTE_BIT`

- The shader code for the entry point identified by `stage` and the rest of the state identified by this structure must adhere to the pipeline linking rules described in the Shader Interfaces chapter

- `layout` must be consistent with the layout of the compute shader specified in `stage`

- The number of resources in `layout` accessible to the compute shader stage must be less than or equal to `VkPhysicalDeviceLimits`::`maxPerStageResources`

- `flags` must not include `VK_PIPELINE_CREATE_LIBRARY_BIT_KHR`

- `flags` must not include `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_ANY_HIT_SHADERS_BIT_KHR`

- `flags` must not include `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_CLOSEST_HIT_SHADERS_BIT_KHR`

- `flags` must not include `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_MISS_SHADERS_BIT_KHR`

- `flags` must not include `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_INTERSECTION_SHADERS_BIT_KHR`

- `flags` must not include `VK_PIPELINE_CREATE_RAY_TRACING_SKIP_TRIANGLES_BIT_KHR`

- `flags` must not include `VK_PIPELINE_CREATE_RAY_TRACING_SKIP_AABBS_BIT_KHR`

- `flags` must not include `VK_PIPELINE_CREATE_INDIRECT_BINDABLE_BIT_NV`

- If the `pipelineCreationCacheControl` feature is not enabled, `flags` must not include `VK_PIPELINE_CREATE_FAIL_ON_PIPELINE_COMPILE_REQUIRED_BIT_EXT` or `VK_PIPELINE_CREATE_EARLY_RETURN_ON_FAILURE_BIT_EXT`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_COMPUTE_PIPELINE_CREATE_INFO`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkPipelineCompilerControlCreateInfoAMD or VkPipelineCreationFeedbackCreateInfoEXT

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be a valid combination of VkPipelineCreateFlagBits values

- `stage` must be a valid VkPipelineShaderStageCreateInfo structure

- `layout` must be a valid VkPipelineLayout handle

- Both of `basePipelineHandle`, and `layout` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

The `VkPipelineShaderStageCreateInfo` structure is defined as:

    typedef struct VkPipelineShaderStageCreateInfo {
        VkStructureType                     sType;
        const void*                         pNext;
        VkPipelineShaderStageCreateFlags    flags;
        VkShaderStageFlagBits               stage;
        VkShaderModule                      module;
        const char*                         pName;
        const VkSpecializationInfo*         pSpecializationInfo;
    } VkPipelineShaderStageCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkPipelineShaderStageCreateFlagBits specifying how the pipeline shader stage will be generated.

- `stage` is a VkShaderStageFlagBits value specifying a single pipeline stage.

- `module` is a VkShaderModule object containing the shader for this stage.

- `pName` is a pointer to a null-terminated UTF-8 string specifying the entry point name of the shader for this stage.

- `pSpecializationInfo` is a pointer to a VkSpecializationInfo structure, as described in Specialization Constants, or `NULL`.

Valid Usage

- If the geometry shaders feature is not enabled, `stage` must not be `VK_SHADER_STAGE_GEOMETRY_BIT`

- If the tessellation shaders feature is not enabled, `stage` must not be `VK_SHADER_STAGE_TESSELLATION_CONTROL_BIT` or `VK_SHADER_STAGE_TESSELLATION_EVALUATION_BIT`

- If the mesh shader feature is not enabled, `stage` must not be `VK_SHADER_STAGE_MESH_BIT_NV`

- If the task shader feature is not enabled, `stage` must not be `VK_SHADER_STAGE_TASK_BIT_NV`

- `stage` must not be `VK_SHADER_STAGE_ALL_GRAPHICS`, or `VK_SHADER_STAGE_ALL`

- `pName` must be the name of an `OpEntryPoint` in `module` with an execution model that matches `stage`

- If the identified entry point includes any variable in its interface that is declared with the `ClipDistance` `BuiltIn` decoration, that variable must not have an array size greater than `VkPhysicalDeviceLimits`::`maxClipDistances`

- If the identified entry point includes any variable in its interface that is declared with the `CullDistance` `BuiltIn` decoration, that variable must not have an array size greater than `VkPhysicalDeviceLimits`::`maxCullDistances`

- If the identified entry point includes any variables in its interface that are declared with the `ClipDistance` or `CullDistance` `BuiltIn` decoration, those variables must not have array sizes which sum to more than `VkPhysicalDeviceLimits`::`maxCombinedClipAndCullDistances`

- If the identified entry point includes any variable in its interface that is declared with the `SampleMask` `BuiltIn` decoration, that variable must not have an array size greater than `VkPhysicalDeviceLimits`::`maxSampleMaskWords`

- If `stage` is `VK_SHADER_STAGE_VERTEX_BIT`, the identified entry point must not include any input variable in its interface that is decorated with `CullDistance`

- If `stage` is `VK_SHADER_STAGE_TESSELLATION_CONTROL_BIT` or `VK_SHADER_STAGE_TESSELLATION_EVALUATION_BIT`, and the identified entry point has an `OpExecutionMode` instruction that specifies a patch size with `OutputVertices`, the patch size must be greater than `0` and less than or equal to `VkPhysicalDeviceLimits`::`maxTessellationPatchSize`

- If `stage` is `VK_SHADER_STAGE_GEOMETRY_BIT`, the identified entry point must have an `OpExecutionMode` instruction that specifies a maximum output vertex count that is greater than `0` and less than or equal to `VkPhysicalDeviceLimits`::`maxGeometryOutputVertices`

- If `stage` is `VK_SHADER_STAGE_GEOMETRY_BIT`, the identified entry point must have an `OpExecutionMode` instruction that specifies an invocation count that is greater than `0` and less than or equal to `VkPhysicalDeviceLimits`::`maxGeometryShaderInvocations`

- If `stage` is a vertex processing stage, and the identified entry point writes to `Layer` for any primitive, it must write the same value to `Layer` for all vertices of a given primitive

- If `stage` is a vertex processing stage, and the identified entry point writes to `ViewportIndex` for any primitive, it must write the same value to `ViewportIndex` for all vertices of a given primitive

- If `stage` is `VK_SHADER_STAGE_FRAGMENT_BIT`, the identified entry point must not include any output variables in its interface decorated with `CullDistance`

- If `stage` is `VK_SHADER_STAGE_FRAGMENT_BIT`, and the identified entry point writes to `FragDepth` in any execution path, it must write to `FragDepth` in all execution paths

- If `stage` is `VK_SHADER_STAGE_FRAGMENT_BIT`, and the identified entry point writes to `FragStencilRefEXT` in any execution path, it must write to `FragStencilRefEXT` in all execution paths

- If `stage` is `VK_SHADER_STAGE_MESH_BIT_NV`, the identified entry point must have an `OpExecutionMode` instruction that specifies a maximum output vertex count, `OutputVertices`, that is greater than `0` and less than or equal to `VkPhysicalDeviceMeshShaderPropertiesNV`::`maxMeshOutputVertices`.

- If `stage` is `VK_SHADER_STAGE_MESH_BIT_NV`, the identified entry point must have an `OpExecutionMode` instruction that specifies a maximum output primitive count, `OutputPrimitivesNV`, that is greater than `0` and less than or equal to `VkPhysicalDeviceMeshShaderPropertiesNV`::`maxMeshOutputPrimitives`.

- If `flags` has the `VK_PIPELINE_SHADER_STAGE_CREATE_ALLOW_VARYING_SUBGROUP_SIZE_BIT_EXT` flag set, the `subgroupSizeControl` feature must be enabled.

- If `flags` has the `VK_PIPELINE_SHADER_STAGE_CREATE_REQUIRE_FULL_SUBGROUPS_BIT_EXT` flag set, the `computeFullSubgroups` feature must be enabled.

- If a VkPipelineShaderStageRequiredSubgroupSizeCreateInfoEXT structure is included in the `pNext` chain, `flags` must not have the `VK_PIPELINE_SHADER_STAGE_CREATE_ALLOW_VARYING_SUBGROUP_SIZE_BIT_EXT` flag set.

- If a VkPipelineShaderStageRequiredSubgroupSizeCreateInfoEXT structure is included in the `pNext` chain, the `subgroupSizeControl` feature must be enabled, and `stage` must be a valid bit specified in `requiredSubgroupSizeStages`.

- If a VkPipelineShaderStageRequiredSubgroupSizeCreateInfoEXT structure is included in the `pNext` chain and `stage` is `VK_SHADER_STAGE_COMPUTE_BIT`, the local workgroup size of the shader must be less than or equal to the product of VkPipelineShaderStageRequiredSubgroupSizeCreateInfoEXT::`requiredSubgroupSize` and `maxComputeWorkgroupSubgroups`.

- If a VkPipelineShaderStageRequiredSubgroupSizeCreateInfoEXT structure is included in the `pNext` chain, and `flags` has the `VK_PIPELINE_SHADER_STAGE_CREATE_REQUIRE_FULL_SUBGROUPS_BIT_EXT` flag set, the local workgroup size in the X dimension of the pipeline must be a multiple of VkPipelineShaderStageRequiredSubgroupSizeCreateInfoEXT::`requiredSubgroupSize`.

- If `flags` has both the `VK_PIPELINE_SHADER_STAGE_CREATE_REQUIRE_FULL_SUBGROUPS_BIT_EXT` and `VK_PIPELINE_SHADER_STAGE_CREATE_ALLOW_VARYING_SUBGROUP_SIZE_BIT_EXT` flags set, the local workgroup size in the X dimension of the pipeline must be a multiple of `maxSubgroupSize`.

- If `flags` has the `VK_PIPELINE_SHADER_STAGE_CREATE_REQUIRE_FULL_SUBGROUPS_BIT_EXT` flag set and `flags` does not have the `VK_PIPELINE_SHADER_STAGE_CREATE_ALLOW_VARYING_SUBGROUP_SIZE_BIT_EXT` flag set and no VkPipelineShaderStageRequiredSubgroupSizeCreateInfoEXT structure is included in the `pNext` chain, the local workgroup size in the X dimension of the pipeline must be a multiple of `subgroupSize`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO`

- `pNext` must be `NULL` or a pointer to a valid instance of VkPipelineShaderStageRequiredSubgroupSizeCreateInfoEXT

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be a valid combination of VkPipelineShaderStageCreateFlagBits values

- `stage` must be a valid VkShaderStageFlagBits value

- `module` must be a valid VkShaderModule handle

- `pName` must be a null-terminated UTF-8 string

- If `pSpecializationInfo` is not `NULL`, `pSpecializationInfo` must be a valid pointer to a valid VkSpecializationInfo structure

    typedef VkFlags VkPipelineShaderStageCreateFlags;

`VkPipelineShaderStageCreateFlags` is a bitmask type for setting a mask of zero or more VkPipelineShaderStageCreateFlagBits.

Possible values of the `flags` member of VkPipelineShaderStageCreateInfo specifying how a pipeline shader stage is created, are:

    typedef enum VkPipelineShaderStageCreateFlagBits {
        VK_PIPELINE_SHADER_STAGE_CREATE_ALLOW_VARYING_SUBGROUP_SIZE_BIT_EXT = 0x00000001,
        VK_PIPELINE_SHADER_STAGE_CREATE_REQUIRE_FULL_SUBGROUPS_BIT_EXT = 0x00000002,
        VK_PIPELINE_SHADER_STAGE_CREATE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkPipelineShaderStageCreateFlagBits;

- `VK_PIPELINE_SHADER_STAGE_CREATE_ALLOW_VARYING_SUBGROUP_SIZE_BIT_EXT` specifies that the `SubgroupSize` may vary in the shader stage.

- `VK_PIPELINE_SHADER_STAGE_CREATE_REQUIRE_FULL_SUBGROUPS_BIT_EXT` specifies that the subgroup sizes must be launched with all invocations active in the compute stage.

| Note If `VK_PIPELINE_SHADER_STAGE_CREATE_ALLOW_VARYING_SUBGROUP_SIZE_BIT_EXT` and `VK_PIPELINE_SHADER_STAGE_CREATE_REQUIRE_FULL_SUBGROUPS_BIT_EXT` are specified and `minSubgroupSize` does not equal `maxSubgroupSize` and no required subgroup size is specified, then the only way to guarantee that the 'X' dimension of the local workgroup size is a multiple of `SubgroupSize` is to make it a multiple of `maxSubgroupSize`. Under these conditions, you are guaranteed full subgroups but not any particular subgroup size.

Commands and structures which need to specify one or more shader stages do so using a bitmask whose bits correspond to stages. Bits which can be set to specify shader stages are:

    typedef enum VkShaderStageFlagBits {
        VK_SHADER_STAGE_VERTEX_BIT = 0x00000001,
        VK_SHADER_STAGE_TESSELLATION_CONTROL_BIT = 0x00000002,
        VK_SHADER_STAGE_TESSELLATION_EVALUATION_BIT = 0x00000004,
        VK_SHADER_STAGE_GEOMETRY_BIT = 0x00000008,
        VK_SHADER_STAGE_FRAGMENT_BIT = 0x00000010,
        VK_SHADER_STAGE_COMPUTE_BIT = 0x00000020,
        VK_SHADER_STAGE_ALL_GRAPHICS = 0x0000001F,
        VK_SHADER_STAGE_ALL = 0x7FFFFFFF,
        VK_SHADER_STAGE_RAYGEN_BIT_KHR = 0x00000100,
        VK_SHADER_STAGE_ANY_HIT_BIT_KHR = 0x00000200,
        VK_SHADER_STAGE_CLOSEST_HIT_BIT_KHR = 0x00000400,
        VK_SHADER_STAGE_MISS_BIT_KHR = 0x00000800,
        VK_SHADER_STAGE_INTERSECTION_BIT_KHR = 0x00001000,
        VK_SHADER_STAGE_CALLABLE_BIT_KHR = 0x00002000,
        VK_SHADER_STAGE_TASK_BIT_NV = 0x00000040,
        VK_SHADER_STAGE_MESH_BIT_NV = 0x00000080,
        VK_SHADER_STAGE_RAYGEN_BIT_NV = VK_SHADER_STAGE_RAYGEN_BIT_KHR,
        VK_SHADER_STAGE_ANY_HIT_BIT_NV = VK_SHADER_STAGE_ANY_HIT_BIT_KHR,
        VK_SHADER_STAGE_CLOSEST_HIT_BIT_NV = VK_SHADER_STAGE_CLOSEST_HIT_BIT_KHR,
        VK_SHADER_STAGE_MISS_BIT_NV = VK_SHADER_STAGE_MISS_BIT_KHR,
        VK_SHADER_STAGE_INTERSECTION_BIT_NV = VK_SHADER_STAGE_INTERSECTION_BIT_KHR,
        VK_SHADER_STAGE_CALLABLE_BIT_NV = VK_SHADER_STAGE_CALLABLE_BIT_KHR,
        VK_SHADER_STAGE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkShaderStageFlagBits;

- `VK_SHADER_STAGE_VERTEX_BIT` specifies the vertex stage.

- `VK_SHADER_STAGE_TESSELLATION_CONTROL_BIT` specifies the tessellation control stage.

- `VK_SHADER_STAGE_TESSELLATION_EVALUATION_BIT` specifies the tessellation evaluation stage.

- `VK_SHADER_STAGE_GEOMETRY_BIT` specifies the geometry stage.

- `VK_SHADER_STAGE_FRAGMENT_BIT` specifies the fragment stage.

- `VK_SHADER_STAGE_COMPUTE_BIT` specifies the compute stage.

- `VK_SHADER_STAGE_ALL_GRAPHICS` is a combination of bits used as shorthand to specify all graphics stages defined above (excluding the compute stage).

- `VK_SHADER_STAGE_ALL` is a combination of bits used as shorthand to specify all shader stages supported by the device, including all additional stages which are introduced by extensions.

- `VK_SHADER_STAGE_TASK_BIT_NV` specifies the task stage.

- `VK_SHADER_STAGE_MESH_BIT_NV` specifies the mesh stage.

- `VK_SHADER_STAGE_RAYGEN_BIT_KHR` specifies the ray generation stage.

- `VK_SHADER_STAGE_ANY_HIT_BIT_KHR` specifies the any-hit stage.

- `VK_SHADER_STAGE_CLOSEST_HIT_BIT_KHR` specifies the closest hit stage.

- `VK_SHADER_STAGE_MISS_BIT_KHR` specifies the miss stage.

- `VK_SHADER_STAGE_INTERSECTION_BIT_KHR` specifies the intersection stage.

- `VK_SHADER_STAGE_CALLABLE_BIT_KHR` specifies the callable stage.

| Note `VK_SHADER_STAGE_ALL_GRAPHICS` only includes the original five graphics stages included in Vulkan 1.0, and not any stages added by extensions. Thus, it may not have the desired effect in all cases.

    typedef VkFlags VkShaderStageFlags;

`VkShaderStageFlags` is a bitmask type for setting a mask of zero or more VkShaderStageFlagBits.

The `VkPipelineShaderStageRequiredSubgroupSizeCreateInfoEXT` structure is defined as:

    typedef struct VkPipelineShaderStageRequiredSubgroupSizeCreateInfoEXT {
        VkStructureType    sType;
        void*              pNext;
        uint32_t           requiredSubgroupSize;
    } VkPipelineShaderStageRequiredSubgroupSizeCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `requiredSubgroupSize` is an unsigned integer value that specifies the required subgroup size for the newly created pipeline shader stage.

Valid Usage

- `requiredSubgroupSize` must be a power-of-two integer.

- `requiredSubgroupSize` must be greater or equal to minSubgroupSize.

- `requiredSubgroupSize` must be less than or equal to maxSubgroupSize.

If a `VkPipelineShaderStageRequiredSubgroupSizeCreateInfoEXT` structure is included in the `pNext` chain of VkPipelineShaderStageCreateInfo, it specifies that the pipeline shader stage being compiled has a required subgroup size.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_REQUIRED_SUBGROUP_SIZE_CREATE_INFO_EXT`

### 9.2. Graphics Pipelines

Graphics pipelines consist of multiple shader stages, multiple fixed-function pipeline stages, and a pipeline layout.

To create graphics pipelines, call:

    VkResult vkCreateGraphicsPipelines(
        VkDevice                                    device,
        VkPipelineCache                             pipelineCache,
        uint32_t                                    createInfoCount,
        const VkGraphicsPipelineCreateInfo*         pCreateInfos,
        const VkAllocationCallbacks*                pAllocator,
        VkPipeline*                                 pPipelines);

- `device` is the logical device that creates the graphics pipelines.

- `pipelineCache` is either VK_NULL_HANDLE, indicating that pipeline caching is disabled; or the handle of a valid pipeline cache object, in which case use of that cache is enabled for the duration of the command.

- `createInfoCount` is the length of the `pCreateInfos` and `pPipelines` arrays.

- `pCreateInfos` is a pointer to an array of VkGraphicsPipelineCreateInfo structures.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pPipelines` is a pointer to an array of VkPipeline handles in which the resulting graphics pipeline objects are returned.

The VkGraphicsPipelineCreateInfo structure includes an array of shader create info structures containing all the desired active shader stages, as well as creation info to define all relevant fixed-function stages, and a pipeline layout.

Valid Usage

- If the `flags` member of any element of `pCreateInfos` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, and the `basePipelineIndex` member of that same element is not `-1`, `basePipelineIndex` must be less than the index into `pCreateInfos` that corresponds to that element

- If the `flags` member of any element of `pCreateInfos` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, the base pipeline must have been created with the `VK_PIPELINE_CREATE_ALLOW_DERIVATIVES_BIT` flag set

- If `pipelineCache` was created with `VK_PIPELINE_CACHE_CREATE_EXTERNALLY_SYNCHRONIZED_BIT_EXT`, host access to `pipelineCache` must be externally synchronized.

| Note An implicit cache may be provided by the implementation or a layer. For this reason, it is still valid to set `VK_PIPELINE_CREATE_FAIL_ON_PIPELINE_COMPILE_REQUIRED_BIT_EXT` on `flags` for any element of `pCreateInfos` while passing VK_NULL_HANDLE for `pipelineCache`.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `pipelineCache` is not VK_NULL_HANDLE, `pipelineCache` must be a valid VkPipelineCache handle

- `pCreateInfos` must be a valid pointer to an array of `createInfoCount` valid VkGraphicsPipelineCreateInfo structures

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pPipelines` must be a valid pointer to an array of `createInfoCount` VkPipeline handles

- `createInfoCount` must be greater than `0`

- If `pipelineCache` is a valid handle, it must have been created, allocated, or retrieved from `device`

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_INVALID_SHADER_NV`

The `VkGraphicsPipelineCreateInfo` structure is defined as:

    typedef struct VkGraphicsPipelineCreateInfo {
        VkStructureType                                  sType;
        const void*                                      pNext;
        VkPipelineCreateFlags                            flags;
        uint32_t                                         stageCount;
        const VkPipelineShaderStageCreateInfo*           pStages;
        const VkPipelineVertexInputStateCreateInfo*      pVertexInputState;
        const VkPipelineInputAssemblyStateCreateInfo*    pInputAssemblyState;
        const VkPipelineTessellationStateCreateInfo*     pTessellationState;
        const VkPipelineViewportStateCreateInfo*         pViewportState;
        const VkPipelineRasterizationStateCreateInfo*    pRasterizationState;
        const VkPipelineMultisampleStateCreateInfo*      pMultisampleState;
        const VkPipelineDepthStencilStateCreateInfo*     pDepthStencilState;
        const VkPipelineColorBlendStateCreateInfo*       pColorBlendState;
        const VkPipelineDynamicStateCreateInfo*          pDynamicState;
        VkPipelineLayout                                 layout;
        VkRenderPass                                     renderPass;
        uint32_t                                         subpass;
        VkPipeline                                       basePipelineHandle;
        int32_t                                          basePipelineIndex;
    } VkGraphicsPipelineCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkPipelineCreateFlagBits specifying how the pipeline will be generated.

- `stageCount` is the number of entries in the `pStages` array.

- `pStages` is a pointer to an array of `stageCount` VkPipelineShaderStageCreateInfo structures describing the set of the shader stages to be included in the graphics pipeline.

- `pVertexInputState` is a pointer to a VkPipelineVertexInputStateCreateInfo structure. It is ignored if the pipeline includes a mesh shader stage.

- `pInputAssemblyState` is a pointer to a VkPipelineInputAssemblyStateCreateInfo structure which determines input assembly behavior, as described in Drawing Commands. It is ignored if the pipeline includes a mesh shader stage.

- `pTessellationState` is a pointer to a VkPipelineTessellationStateCreateInfo structure, and is ignored if the pipeline does not include a tessellation control shader stage and tessellation evaluation shader stage.

- `pViewportState` is a pointer to a VkPipelineViewportStateCreateInfo structure, and is ignored if the pipeline has rasterization disabled.

- `pRasterizationState` is a pointer to a VkPipelineRasterizationStateCreateInfo structure.

- `pMultisampleState` is a pointer to a VkPipelineMultisampleStateCreateInfo structure, and is ignored if the pipeline has rasterization disabled.

- `pDepthStencilState` is a pointer to a VkPipelineDepthStencilStateCreateInfo structure, and is ignored if the pipeline has rasterization disabled or if the subpass of the render pass the pipeline is created against does not use a depth/stencil attachment.

- `pColorBlendState` is a pointer to a VkPipelineColorBlendStateCreateInfo structure, and is ignored if the pipeline has rasterization disabled or if the subpass of the render pass the pipeline is created against does not use any color attachments.

- `pDynamicState` is a pointer to a VkPipelineDynamicStateCreateInfo structure, and is used to indicate which properties of the pipeline state object are dynamic and can be changed independently of the pipeline state. This can be `NULL`, which means no state in the pipeline is considered dynamic.

- `layout` is the description of binding locations used by both the pipeline and descriptor sets used with the pipeline.

- `renderPass` is a handle to a render pass object describing the environment in which the pipeline will be used; the pipeline must only be used with an instance of any render pass compatible with the one provided. See Render Pass Compatibility for more information.

- `subpass` is the index of the subpass in the render pass where this pipeline will be used.

- `basePipelineHandle` is a pipeline to derive from.

- `basePipelineIndex` is an index into the `pCreateInfos` parameter to use as a pipeline to derive from.

The parameters `basePipelineHandle` and `basePipelineIndex` are described in more detail in Pipeline Derivatives.

If any shader stage fails to compile, the compile log will be reported back to the application, and `VK_ERROR_INVALID_SHADER_NV` will be generated.

Valid Usage

- If `flags` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, and `basePipelineIndex` is -1, `basePipelineHandle` must be a valid handle to a graphics `VkPipeline`

- If `flags` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, and `basePipelineHandle` is VK_NULL_HANDLE, `basePipelineIndex` must be a valid index into the calling command’s `pCreateInfos` parameter

- If `flags` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, and `basePipelineIndex` is not -1, `basePipelineHandle` must be VK_NULL_HANDLE

- If `flags` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, and `basePipelineHandle` is not VK_NULL_HANDLE, `basePipelineIndex` must be -1

- The `stage` member of each element of `pStages` must be unique

- The geometric shader stages provided in `pStages` must be either from the mesh shading pipeline (`stage` is `VK_SHADER_STAGE_TASK_BIT_NV` or `VK_SHADER_STAGE_MESH_BIT_NV`) or from the primitive shading pipeline (`stage` is `VK_SHADER_STAGE_VERTEX_BIT`, `VK_SHADER_STAGE_TESSELLATION_CONTROL_BIT`, `VK_SHADER_STAGE_TESSELLATION_EVALUATION_BIT`, or `VK_SHADER_STAGE_GEOMETRY_BIT`).

- The `stage` member of one element of `pStages` must be either `VK_SHADER_STAGE_VERTEX_BIT` or `VK_SHADER_STAGE_MESH_BIT_NV`.

- The `stage` member of each element of `pStages` must not be `VK_SHADER_STAGE_COMPUTE_BIT`

- If `pStages` includes a tessellation control shader stage, it must include a tessellation evaluation shader stage

- If `pStages` includes a tessellation evaluation shader stage, it must include a tessellation control shader stage

- If `pStages` includes a tessellation control shader stage and a tessellation evaluation shader stage, `pTessellationState` must be a valid pointer to a valid `VkPipelineTessellationStateCreateInfo` structure

- If `pStages` includes tessellation shader stages, the shader code of at least one stage must contain an `OpExecutionMode` instruction that specifies the type of subdivision in the pipeline

- If `pStages` includes tessellation shader stages, and the shader code of both stages contain an `OpExecutionMode` instruction that specifies the type of subdivision in the pipeline, they must both specify the same subdivision mode

- If `pStages` includes tessellation shader stages, the shader code of at least one stage must contain an `OpExecutionMode` instruction that specifies the output patch size in the pipeline

- If `pStages` includes tessellation shader stages, and the shader code of both contain an `OpExecutionMode` instruction that specifies the out patch size in the pipeline, they must both specify the same patch size

- If `pStages` includes tessellation shader stages, the `topology` member of `pInputAssembly` must be `VK_PRIMITIVE_TOPOLOGY_PATCH_LIST`

- If the `topology` member of `pInputAssembly` is `VK_PRIMITIVE_TOPOLOGY_PATCH_LIST`, `pStages` must include tessellation shader stages

- If `pStages` includes a geometry shader stage, and does not include any tessellation shader stages, its shader code must contain an `OpExecutionMode` instruction that specifies an input primitive type that is compatible with the primitive topology specified in `pInputAssembly`

- If `pStages` includes a geometry shader stage, and also includes tessellation shader stages, its shader code must contain an `OpExecutionMode` instruction that specifies an input primitive type that is compatible with the primitive topology that is output by the tessellation stages

- If `pStages` includes a fragment shader stage and a geometry shader stage, and the fragment shader code reads from an input variable that is decorated with `PrimitiveID`, then the geometry shader code must write to a matching output variable, decorated with `PrimitiveID`, in all execution paths

- If `pStages` includes a fragment shader stage, its shader code must not read from any input attachment that is defined as `VK_ATTACHMENT_UNUSED` in `subpass`

- The shader code for the entry points identified by `pStages`, and the rest of the state identified by this structure must adhere to the pipeline linking rules described in the Shader Interfaces chapter

- If rasterization is not disabled and `subpass` uses a depth/stencil attachment in `renderPass` that has a layout of `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL` or `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL` in the `VkAttachmentReference` defined by `subpass`, the `depthWriteEnable` member of `pDepthStencilState` must be `VK_FALSE`

- If rasterization is not disabled and `subpass` uses a depth/stencil attachment in `renderPass` that has a layout of `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL` or `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL` in the `VkAttachmentReference` defined by `subpass`, the `failOp`, `passOp` and `depthFailOp` members of each of the `front` and `back` members of `pDepthStencilState` must be `VK_STENCIL_OP_KEEP`

- If rasterization is not disabled and the subpass uses color attachments, then for each color attachment in the subpass the `blendEnable` member of the corresponding element of the `pAttachment` member of `pColorBlendState` must be `VK_FALSE` if the attached image’s format features does not contain `VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BLEND_BIT`.

- If rasterization is not disabled and the subpass uses color attachments, the `attachmentCount` member of `pColorBlendState` must be equal to the `colorAttachmentCount` used to create `subpass`

- If no element of the `pDynamicStates` member of `pDynamicState` is `VK_DYNAMIC_STATE_VIEWPORT`, the `pViewports` member of `pViewportState` must be a valid pointer to an array of `pViewportState->viewportCount` valid `VkViewport` structures

- If no element of the `pDynamicStates` member of `pDynamicState` is `VK_DYNAMIC_STATE_SCISSOR`, the `pScissors` member of `pViewportState` must be a valid pointer to an array of `pViewportState->scissorCount` `VkRect2D` structures

- If the wide lines feature is not enabled, and no element of the `pDynamicStates` member of `pDynamicState` is `VK_DYNAMIC_STATE_LINE_WIDTH`, the `lineWidth` member of `pRasterizationState` must be `1.0`

- If the `rasterizerDiscardEnable` member of `pRasterizationState` is `VK_FALSE`, `pViewportState` must be a valid pointer to a valid `VkPipelineViewportStateCreateInfo` structure

- If the `rasterizerDiscardEnable` member of `pRasterizationState` is `VK_FALSE`, `pMultisampleState` must be a valid pointer to a valid `VkPipelineMultisampleStateCreateInfo` structure

- If the `rasterizerDiscardEnable` member of `pRasterizationState` is `VK_FALSE`, and `subpass` uses a depth/stencil attachment, `pDepthStencilState` must be a valid pointer to a valid `VkPipelineDepthStencilStateCreateInfo` structure

- If the `rasterizerDiscardEnable` member of `pRasterizationState` is `VK_FALSE`, and `subpass` uses color attachments, `pColorBlendState` must be a valid pointer to a valid `VkPipelineColorBlendStateCreateInfo` structure

- If the depth bias clamping feature is not enabled, no element of the `pDynamicStates` member of `pDynamicState` is `VK_DYNAMIC_STATE_DEPTH_BIAS`, and the `depthBiasEnable` member of `pRasterizationState` is `VK_TRUE`, the `depthBiasClamp` member of `pRasterizationState` must be `0.0`

- If the `VK_EXT_depth_range_unrestricted` extension is not enabled and no element of the `pDynamicStates` member of `pDynamicState` is `VK_DYNAMIC_STATE_DEPTH_BOUNDS`, and the `depthBoundsTestEnable` member of `pDepthStencilState` is `VK_TRUE`, the `minDepthBounds` and `maxDepthBounds` members of `pDepthStencilState` must be between `0.0` and `1.0`, inclusive

- If no element of the `pDynamicStates` member of `pDynamicState` is `VK_DYNAMIC_STATE_SAMPLE_LOCATIONS_EXT`, and the `sampleLocationsEnable` member of a VkPipelineSampleLocationsStateCreateInfoEXT structure included in the `pNext` chain of `pMultisampleState` is `VK_TRUE`, `sampleLocationsInfo.sampleLocationGridSize.width` must evenly divide VkMultisamplePropertiesEXT::`sampleLocationGridSize.width` as returned by vkGetPhysicalDeviceMultisamplePropertiesEXT with a `samples` parameter equaling `rasterizationSamples`

- If no element of the `pDynamicStates` member of `pDynamicState` is `VK_DYNAMIC_STATE_SAMPLE_LOCATIONS_EXT`, and the `sampleLocationsEnable` member of a VkPipelineSampleLocationsStateCreateInfoEXT structure included in the `pNext` chain of `pMultisampleState` is `VK_TRUE`, `sampleLocationsInfo.sampleLocationGridSize.height` must evenly divide VkMultisamplePropertiesEXT::`sampleLocationGridSize.height` as returned by vkGetPhysicalDeviceMultisamplePropertiesEXT with a `samples` parameter equaling `rasterizationSamples`

- If no element of the `pDynamicStates` member of `pDynamicState` is `VK_DYNAMIC_STATE_SAMPLE_LOCATIONS_EXT`, and the `sampleLocationsEnable` member of a VkPipelineSampleLocationsStateCreateInfoEXT structure included in the `pNext` chain of `pMultisampleState` is `VK_TRUE`, `sampleLocationsInfo.sampleLocationsPerPixel` must equal `rasterizationSamples`

- If the `sampleLocationsEnable` member of a VkPipelineSampleLocationsStateCreateInfoEXT structure included in the `pNext` chain of `pMultisampleState` is `VK_TRUE`, the fragment shader code must not statically use the extended instruction `InterpolateAtSample`

- `layout` must be consistent with all shaders specified in `pStages`

- If neither the `VK_AMD_mixed_attachment_samples` nor the `VK_NV_framebuffer_mixed_samples` extensions are enabled, and if `subpass` uses color and/or depth/stencil attachments, then the `rasterizationSamples` member of `pMultisampleState` must be the same as the sample count for those subpass attachments

- If the `VK_AMD_mixed_attachment_samples` extension is enabled, and if `subpass` uses color and/or depth/stencil attachments, then the `rasterizationSamples` member of `pMultisampleState` must equal the maximum of the sample counts of those subpass attachments

- If the `VK_NV_framebuffer_mixed_samples` extension is enabled, and if `subpass` has a depth/stencil attachment and depth test, stencil test, or depth bounds test are enabled, then the `rasterizationSamples` member of `pMultisampleState` must be the same as the sample count of the depth/stencil attachment

- If the `VK_NV_framebuffer_mixed_samples` extension is enabled, and if `subpass` has any color attachments, then the `rasterizationSamples` member of `pMultisampleState` must be greater than or equal to the sample count for those subpass attachments

- If the `VK_NV_coverage_reduction_mode` extension is enabled, the coverage reduction mode specified by VkPipelineCoverageReductionStateCreateInfoNV::`coverageReductionMode`, the `rasterizationSamples` member of `pMultisampleState` and the sample counts for the color and depth/stencil attachments (if the subpass has them) must be a valid combination returned by `vkGetPhysicalDeviceSupportedFramebufferMixedSamplesCombinationsNV`

- If `subpass` does not use any color and/or depth/stencil attachments, then the `rasterizationSamples` member of `pMultisampleState` must follow the rules for a zero-attachment subpass

- `subpass` must be a valid subpass within `renderPass`

- If the `renderPass` has multiview enabled and `subpass` has more than one bit set in the view mask and `multiviewTessellationShader` is not enabled, then `pStages` must not include tessellation shaders.

- If the `renderPass` has multiview enabled and `subpass` has more than one bit set in the view mask and `multiviewGeometryShader` is not enabled, then `pStages` must not include a geometry shader.

- If the `renderPass` has multiview enabled and `subpass` has more than one bit set in the view mask, shaders in the pipeline must not write to the `Layer` built-in output

- If the `renderPass` has multiview enabled, then all shaders must not include variables decorated with the `Layer` built-in decoration in their interfaces.

- `flags` must not contain the `VK_PIPELINE_CREATE_DISPATCH_BASE` flag.

- If `pStages` includes a fragment shader stage and an input attachment was referenced by the VkRenderPassInputAttachmentAspectCreateInfo at `renderPass` create time, its shader code must not read from any aspect that was not specified in the `aspectMask` of the corresponding VkInputAttachmentAspectReference structure.

- The number of resources in `layout` accessible to each shader stage that is used by the pipeline must be less than or equal to `VkPhysicalDeviceLimits`::`maxPerStageResources`

- If no element of the `pDynamicStates` member of `pDynamicState` is `VK_DYNAMIC_STATE_VIEWPORT_W_SCALING_NV`, and the `viewportWScalingEnable` member of a VkPipelineViewportWScalingStateCreateInfoNV structure, included in the `pNext` chain of `pViewportState`, is `VK_TRUE`, the `pViewportWScalings` member of the VkPipelineViewportWScalingStateCreateInfoNV must be a pointer to an array of VkPipelineViewportWScalingStateCreateInfoNV::`viewportCount` valid VkViewportWScalingNV structures

- If `pStages` includes a vertex shader stage, `pVertexInputState` must be a valid pointer to a valid VkPipelineVertexInputStateCreateInfo structure

- If `pStages` includes a vertex shader stage, `pInputAssemblyState` must be a valid pointer to a valid VkPipelineInputAssemblyStateCreateInfo structure

- The `Xfb` execution mode can be specified by only one shader stage in `pStages`

- If any shader stage in `pStages` specifies `Xfb` execution mode it must be the last vertex processing stage

- If a `VkPipelineRasterizationStateStreamCreateInfoEXT`::`rasterizationStream` value other than zero is specified, all variables in the output interface of the entry point being compiled decorated with `Position`, `PointSize`, `ClipDistance`, or `CullDistance` must all be decorated with identical `Stream` values that match the `rasterizationStream`

- If `VkPipelineRasterizationStateStreamCreateInfoEXT`::`rasterizationStream` is zero, or not specified, all variables in the output interface of the entry point being compiled decorated with `Position`, `PointSize`, `ClipDistance`, or `CullDistance` must all be decorated with a `Stream` value of zero, or must not specify the `Stream` decoration

- If the last vertex processing stage is a geometry shader, and that geometry shader uses the `GeometryStreams` capability, then `VkPhysicalDeviceTransformFeedbackFeaturesEXT`::`geometryStreams` feature must be enabled

- If there are any mesh shader stages in the pipeline there must not be any shader stage in the pipeline with a `Xfb` execution mode.

- If the `lineRasterizationMode` member of a VkPipelineRasterizationLineStateCreateInfoEXT structure included in the `pNext` chain of `pRasterizationState` is `VK_LINE_RASTERIZATION_MODE_BRESENHAM_EXT` or `VK_LINE_RASTERIZATION_MODE_RECTANGULAR_SMOOTH_EXT` and if rasterization is enabled, then the `alphaToCoverageEnable`, `alphaToOneEnable`, and `sampleShadingEnable` members of `pMultisampleState` must all be `VK_FALSE`

- If the `stippledLineEnable` member of VkPipelineRasterizationLineStateCreateInfoEXT is `VK_TRUE` and no element of the `pDynamicStates` member of `pDynamicState` is `VK_DYNAMIC_STATE_LINE_STIPPLE_EXT`, then the `lineStippleFactor` member of VkPipelineRasterizationLineStateCreateInfoEXT must be in the range [1,256]

- `flags` must not include `VK_PIPELINE_CREATE_LIBRARY_BIT_KHR`

- `flags` must not include `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_ANY_HIT_SHADERS_BIT_KHR`

- `flags` must not include `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_CLOSEST_HIT_SHADERS_BIT_KHR`

- `flags` must not include `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_MISS_SHADERS_BIT_KHR`

- `flags` must not include `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_INTERSECTION_SHADERS_BIT_KHR`

- `flags` must not include `VK_PIPELINE_CREATE_RAY_TRACING_SKIP_TRIANGLES_BIT_KHR`

- `flags` must not include `VK_PIPELINE_CREATE_RAY_TRACING_SKIP_AABBS_BIT_KHR`

- If `flags` includes `VK_PIPELINE_CREATE_INDIRECT_BINDABLE_BIT_NV`, then the `VkPhysicalDeviceDeviceGeneratedCommandsFeaturesNV`→`deviceGeneratedCommands` feature must be enabled

- If the `pipelineCreationCacheControl` feature is not enabled, `flags` must not include `VK_PIPELINE_CREATE_FAIL_ON_PIPELINE_COMPILE_REQUIRED_BIT_EXT` or `VK_PIPELINE_CREATE_EARLY_RETURN_ON_FAILURE_BIT_EXT`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_CREATE_INFO`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkGraphicsPipelineShaderGroupsCreateInfoNV, VkPipelineCompilerControlCreateInfoAMD, VkPipelineCreationFeedbackCreateInfoEXT, VkPipelineDiscardRectangleStateCreateInfoEXT, or VkPipelineRepresentativeFragmentTestStateCreateInfoNV

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be a valid combination of VkPipelineCreateFlagBits values

- `pStages` must be a valid pointer to an array of `stageCount` valid VkPipelineShaderStageCreateInfo structures

- `pRasterizationState` must be a valid pointer to a valid VkPipelineRasterizationStateCreateInfo structure

- If `pDynamicState` is not `NULL`, `pDynamicState` must be a valid pointer to a valid VkPipelineDynamicStateCreateInfo structure

- `layout` must be a valid VkPipelineLayout handle

- `renderPass` must be a valid VkRenderPass handle

- `stageCount` must be greater than `0`

- Each of `basePipelineHandle`, `layout`, and `renderPass` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

Possible values of the `flags` member of VkGraphicsPipelineCreateInfo, VkRayTracingPipelineCreateInfoKHR, and VkComputePipelineCreateInfo, specifying how a pipeline is created, are:

    typedef enum VkPipelineCreateFlagBits {
        VK_PIPELINE_CREATE_DISABLE_OPTIMIZATION_BIT = 0x00000001,
        VK_PIPELINE_CREATE_ALLOW_DERIVATIVES_BIT = 0x00000002,
        VK_PIPELINE_CREATE_DERIVATIVE_BIT = 0x00000004,
        VK_PIPELINE_CREATE_VIEW_INDEX_FROM_DEVICE_INDEX_BIT = 0x00000008,
        VK_PIPELINE_CREATE_DISPATCH_BASE_BIT = 0x00000010,
        VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_ANY_HIT_SHADERS_BIT_KHR = 0x00004000,
        VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_CLOSEST_HIT_SHADERS_BIT_KHR = 0x00008000,
        VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_MISS_SHADERS_BIT_KHR = 0x00010000,
        VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_INTERSECTION_SHADERS_BIT_KHR = 0x00020000,
        VK_PIPELINE_CREATE_RAY_TRACING_SKIP_TRIANGLES_BIT_KHR = 0x00001000,
        VK_PIPELINE_CREATE_RAY_TRACING_SKIP_AABBS_BIT_KHR = 0x00002000,
        VK_PIPELINE_CREATE_DEFER_COMPILE_BIT_NV = 0x00000020,
        VK_PIPELINE_CREATE_CAPTURE_STATISTICS_BIT_KHR = 0x00000040,
        VK_PIPELINE_CREATE_CAPTURE_INTERNAL_REPRESENTATIONS_BIT_KHR = 0x00000080,
        VK_PIPELINE_CREATE_INDIRECT_BINDABLE_BIT_NV = 0x00040000,
        VK_PIPELINE_CREATE_LIBRARY_BIT_KHR = 0x00000800,
        VK_PIPELINE_CREATE_FAIL_ON_PIPELINE_COMPILE_REQUIRED_BIT_EXT = 0x00000100,
        VK_PIPELINE_CREATE_EARLY_RETURN_ON_FAILURE_BIT_EXT = 0x00000200,
        VK_PIPELINE_CREATE_DISPATCH_BASE = VK_PIPELINE_CREATE_DISPATCH_BASE_BIT,
        VK_PIPELINE_CREATE_VIEW_INDEX_FROM_DEVICE_INDEX_BIT_KHR = VK_PIPELINE_CREATE_VIEW_INDEX_FROM_DEVICE_INDEX_BIT,
        VK_PIPELINE_CREATE_DISPATCH_BASE_KHR = VK_PIPELINE_CREATE_DISPATCH_BASE,
        VK_PIPELINE_CREATE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkPipelineCreateFlagBits;

- `VK_PIPELINE_CREATE_DISABLE_OPTIMIZATION_BIT` specifies that the created pipeline will not be optimized. Using this flag may reduce the time taken to create the pipeline.

- `VK_PIPELINE_CREATE_ALLOW_DERIVATIVES_BIT` specifies that the pipeline to be created is allowed to be the parent of a pipeline that will be created in a subsequent call to vkCreateGraphicsPipelines or vkCreateComputePipelines.

- `VK_PIPELINE_CREATE_DERIVATIVE_BIT` specifies that the pipeline to be created will be a child of a previously created parent pipeline.

- `VK_PIPELINE_CREATE_VIEW_INDEX_FROM_DEVICE_INDEX_BIT` specifies that any shader input variables decorated as `ViewIndex` will be assigned values as if they were decorated as `DeviceIndex`.

- `VK_PIPELINE_CREATE_DISPATCH_BASE` specifies that a compute pipeline can be used with vkCmdDispatchBase with a non-zero base workgroup.

- `VK_PIPELINE_CREATE_DEFER_COMPILE_BIT_NV` specifies that a pipeline is created with all shaders in the deferred state. Before using the pipeline the application must call vkCompileDeferredNV exactly once on each shader in the pipeline before using the pipeline.

- `VK_PIPELINE_CREATE_CAPTURE_STATISTICS_BIT_KHR` specifies that the shader compiler should capture statistics for the executables produced by the compile process which can later be retrieved by calling vkGetPipelineExecutableStatisticsKHR. Enabling this flag must not affect the final compiled pipeline but may disable pipeline caching or otherwise affect pipeline creation time.

- `VK_PIPELINE_CREATE_CAPTURE_INTERNAL_REPRESENTATIONS_BIT_KHR` specifies that the shader compiler should capture the internal representations of executables produced by the compile process which can later be retrieved by calling vkGetPipelineExecutableInternalRepresentationsKHR. Enabling this flag must not affect the final compiled pipeline but may disable pipeline caching or otherwise affect pipeline creation time.

- `VK_PIPELINE_CREATE_LIBRARY_BIT_KHR` specifies that the pipeline cannot be used directly, and instead defines a pipeline library that can be combined with other pipelines using the VkPipelineLibraryCreateInfoKHR structure. This is available in raytracing pipelines.

- `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_ANY_HIT_SHADERS_BIT_KHR` specifies that an any hit shader will always be present when an any hit shader would be executed.

- `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_CLOSEST_HIT_SHADERS_BIT_KHR` specifies that a closest hit shader will always be present when a closest hit shader would be executed.

- `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_MISS_SHADERS_BIT_KHR` specifies that a miss shader will always be present when a miss shader would be executed.

- `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_INTERSECTION_SHADERS_BIT_KHR` specifies that an intersection shader will always be present when an intersection shader would be executed.

- `VK_PIPELINE_CREATE_RAY_TRACING_SKIP_TRIANGLES_BIT_KHR` specifies that triangle primitives will be skipped during traversal using `OpTraceKHR`.

- `VK_PIPELINE_CREATE_RAY_TRACING_SKIP_AABBS_BIT_KHR` specifies that AABB primitives will be skipped during traversal using `OpTraceKHR`.

- `VK_PIPELINE_CREATE_INDIRECT_BINDABLE_BIT_NV` specifies that the pipeline can be used in combination with Device-Generated Commands.

- `VK_PIPELINE_CREATE_FAIL_ON_PIPELINE_COMPILE_REQUIRED_BIT_EXT` specifies that pipeline creation will fail if a compile is required for creation of a valid VkPipeline object.

- When creating multiple pipelines, `VK_PIPELINE_CREATE_EARLY_RETURN_ON_FAILURE_BIT_EXT` specifies that control will be returned to the application on failure of the corresponding pipeline rather than continuing to create additional pipelines.

It is valid to set both `VK_PIPELINE_CREATE_ALLOW_DERIVATIVES_BIT` and `VK_PIPELINE_CREATE_DERIVATIVE_BIT`. This allows a pipeline to be both a parent and possibly a child in a pipeline hierarchy. See Pipeline Derivatives for more information.

    typedef VkFlags VkPipelineCreateFlags;

`VkPipelineCreateFlags` is a bitmask type for setting a mask of zero or more VkPipelineCreateFlagBits.

The `VkPipelineDynamicStateCreateInfo` structure is defined as:

    typedef struct VkPipelineDynamicStateCreateInfo {
        VkStructureType                      sType;
        const void*                          pNext;
        VkPipelineDynamicStateCreateFlags    flags;
        uint32_t                             dynamicStateCount;
        const VkDynamicState*                pDynamicStates;
    } VkPipelineDynamicStateCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `dynamicStateCount` is the number of elements in the `pDynamicStates` array.

- `pDynamicStates` is a pointer to an array of VkDynamicState values specifying which pieces of pipeline state will use the values from dynamic state commands rather than from pipeline state creation info.

Valid Usage

- Each element of `pDynamicStates` must be unique

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_DYNAMIC_STATE_CREATE_INFO`

- `pNext` must be `NULL`

- `flags` must be `0`

- If `dynamicStateCount` is not `0`, `pDynamicStates` must be a valid pointer to an array of `dynamicStateCount` valid VkDynamicState values

    typedef VkFlags VkPipelineDynamicStateCreateFlags;

`VkPipelineDynamicStateCreateFlags` is a bitmask type for setting a mask, but is currently reserved for future use.

The source of different pieces of dynamic state is specified by the VkPipelineDynamicStateCreateInfo::`pDynamicStates` property of the currently active pipeline, each of whose elements must be one of the values:

    typedef enum VkDynamicState {
        VK_DYNAMIC_STATE_VIEWPORT = 0,
        VK_DYNAMIC_STATE_SCISSOR = 1,
        VK_DYNAMIC_STATE_LINE_WIDTH = 2,
        VK_DYNAMIC_STATE_DEPTH_BIAS = 3,
        VK_DYNAMIC_STATE_BLEND_CONSTANTS = 4,
        VK_DYNAMIC_STATE_DEPTH_BOUNDS = 5,
        VK_DYNAMIC_STATE_STENCIL_COMPARE_MASK = 6,
        VK_DYNAMIC_STATE_STENCIL_WRITE_MASK = 7,
        VK_DYNAMIC_STATE_STENCIL_REFERENCE = 8,
        VK_DYNAMIC_STATE_VIEWPORT_W_SCALING_NV = 1000087000,
        VK_DYNAMIC_STATE_DISCARD_RECTANGLE_EXT = 1000099000,
        VK_DYNAMIC_STATE_SAMPLE_LOCATIONS_EXT = 1000143000,
        VK_DYNAMIC_STATE_VIEWPORT_SHADING_RATE_PALETTE_NV = 1000164004,
        VK_DYNAMIC_STATE_VIEWPORT_COARSE_SAMPLE_ORDER_NV = 1000164006,
        VK_DYNAMIC_STATE_EXCLUSIVE_SCISSOR_NV = 1000205001,
        VK_DYNAMIC_STATE_LINE_STIPPLE_EXT = 1000259000,
        VK_DYNAMIC_STATE_MAX_ENUM = 0x7FFFFFFF
    } VkDynamicState;

- `VK_DYNAMIC_STATE_VIEWPORT` specifies that the `pViewports` state in `VkPipelineViewportStateCreateInfo` will be ignored and must be set dynamically with vkCmdSetViewport before any draw commands. The number of viewports used by a pipeline is still specified by the `viewportCount` member of `VkPipelineViewportStateCreateInfo`.

- `VK_DYNAMIC_STATE_SCISSOR` specifies that the `pScissors` state in `VkPipelineViewportStateCreateInfo` will be ignored and must be set dynamically with vkCmdSetScissor before any draw commands. The number of scissor rectangles used by a pipeline is still specified by the `scissorCount` member of `VkPipelineViewportStateCreateInfo`.

- `VK_DYNAMIC_STATE_LINE_WIDTH` specifies that the `lineWidth` state in `VkPipelineRasterizationStateCreateInfo` will be ignored and must be set dynamically with vkCmdSetLineWidth before any draw commands that generate line primitives for the rasterizer.

- `VK_DYNAMIC_STATE_DEPTH_BIAS` specifies that the `depthBiasConstantFactor`, `depthBiasClamp` and `depthBiasSlopeFactor` states in `VkPipelineRasterizationStateCreateInfo` will be ignored and must be set dynamically with vkCmdSetDepthBias before any draws are performed with `depthBiasEnable` in `VkPipelineRasterizationStateCreateInfo` set to `VK_TRUE`.

- `VK_DYNAMIC_STATE_BLEND_CONSTANTS` specifies that the `blendConstants` state in `VkPipelineColorBlendStateCreateInfo` will be ignored and must be set dynamically with vkCmdSetBlendConstants before any draws are performed with a pipeline state with `VkPipelineColorBlendAttachmentState` member `blendEnable` set to `VK_TRUE` and any of the blend functions using a constant blend color.

- `VK_DYNAMIC_STATE_DEPTH_BOUNDS` specifies that the `minDepthBounds` and `maxDepthBounds` states of VkPipelineDepthStencilStateCreateInfo will be ignored and must be set dynamically with vkCmdSetDepthBounds before any draws are performed with a pipeline state with `VkPipelineDepthStencilStateCreateInfo` member `depthBoundsTestEnable` set to `VK_TRUE`.

- `VK_DYNAMIC_STATE_STENCIL_COMPARE_MASK` specifies that the `compareMask` state in `VkPipelineDepthStencilStateCreateInfo` for both `front` and `back` will be ignored and must be set dynamically with vkCmdSetStencilCompareMask before any draws are performed with a pipeline state with `VkPipelineDepthStencilStateCreateInfo` member `stencilTestEnable` set to `VK_TRUE`

- `VK_DYNAMIC_STATE_STENCIL_WRITE_MASK` specifies that the `writeMask` state in `VkPipelineDepthStencilStateCreateInfo` for both `front` and `back` will be ignored and must be set dynamically with vkCmdSetStencilWriteMask before any draws are performed with a pipeline state with `VkPipelineDepthStencilStateCreateInfo` member `stencilTestEnable` set to `VK_TRUE`

- `VK_DYNAMIC_STATE_STENCIL_REFERENCE` specifies that the `reference` state in `VkPipelineDepthStencilStateCreateInfo` for both `front` and `back` will be ignored and must be set dynamically with vkCmdSetStencilReference before any draws are performed with a pipeline state with `VkPipelineDepthStencilStateCreateInfo` member `stencilTestEnable` set to `VK_TRUE`

- `VK_DYNAMIC_STATE_VIEWPORT_W_SCALING_NV` specifies that the `pViewportScalings` state in VkPipelineViewportWScalingStateCreateInfoNV will be ignored and must be set dynamically with vkCmdSetViewportWScalingNV before any draws are performed with a pipeline state with VkPipelineViewportWScalingStateCreateInfoNV member `viewportScalingEnable` set to `VK_TRUE`

- `VK_DYNAMIC_STATE_DISCARD_RECTANGLE_EXT` specifies that the `pDiscardRectangles` state in VkPipelineDiscardRectangleStateCreateInfoEXT will be ignored and must be set dynamically with vkCmdSetDiscardRectangleEXT before any draw or clear commands. The VkDiscardRectangleModeEXT and the number of active discard rectangles is still specified by the `discardRectangleMode` and `discardRectangleCount` members of `VkPipelineDiscardRectangleStateCreateInfoEXT`.

- `VK_DYNAMIC_STATE_SAMPLE_LOCATIONS_EXT` specifies that the `sampleLocationsInfo` state in VkPipelineSampleLocationsStateCreateInfoEXT will be ignored and must be set dynamically with vkCmdSetSampleLocationsEXT before any draw or clear commands. Enabling custom sample locations is still indicated by the `sampleLocationsEnable` member of `VkPipelineSampleLocationsStateCreateInfoEXT`.

- `VK_DYNAMIC_STATE_EXCLUSIVE_SCISSOR_NV` specifies that the `pExclusiveScissors` state in `VkPipelineViewportExclusiveScissorStateCreateInfoNV` will be ignored and must be set dynamically with vkCmdSetExclusiveScissorNV before any draw commands. The number of exclusive scissor rectangles used by a pipeline is still specified by the `exclusiveScissorCount` member of `VkPipelineViewportExclusiveScissorStateCreateInfoNV`.

- `VK_DYNAMIC_STATE_VIEWPORT_SHADING_RATE_PALETTE_NV` specifies that the `pShadingRatePalettes` state in VkPipelineViewportShadingRateImageStateCreateInfoNV will be ignored and must be set dynamically with vkCmdSetViewportShadingRatePaletteNV before any draw commands.

- `VK_DYNAMIC_STATE_VIEWPORT_COARSE_SAMPLE_ORDER_NV` specifies that the coarse sample order state in VkPipelineViewportCoarseSampleOrderStateCreateInfoNV will be ignored and must be set dynamically with vkCmdSetCoarseSampleOrderNV before any draw commands.

- `VK_DYNAMIC_STATE_LINE_STIPPLE_EXT` specifies that the `lineStippleFactor` and `lineStipplePattern` state in VkPipelineRasterizationLineStateCreateInfoEXT will be ignored and must be set dynamically with vkCmdSetLineStippleEXT before any draws are performed with a pipeline state with VkPipelineRasterizationLineStateCreateInfoEXT member `stippledLineEnable` set to `VK_TRUE`.

#### 9.2.1. Valid Combinations of Stages for Graphics Pipelines

The geometric primitive processing can either be handled on a per primitive basis by the vertex, tessellation, and geometry shader stages, or on a per mesh basis using task and mesh shader stages. If the pipeline includes a mesh shader stage, it uses the mesh pipeline, otherwise it uses the primitive pipeline.

If a task shader is omitted, the task shading stage is skipped.

If tessellation shader stages are omitted, the tessellation shading and fixed-function stages of the pipeline are skipped.

If a geometry shader is omitted, the geometry shading stage is skipped.

If a fragment shader is omitted, fragment color outputs have undefined values, and the fragment depth value is unmodified. This can be useful for depth-only rendering.

Presence of a shader stage in a pipeline is indicated by including a valid `VkPipelineShaderStageCreateInfo` with `module` and `pName` selecting an entry point from a shader module, where that entry point is valid for the stage specified by `stage`.

Presence of some of the fixed-function stages in the pipeline is implicitly derived from enabled shaders and provided state. For example, the fixed-function tessellator is always present when the pipeline has valid Tessellation Control and Tessellation Evaluation shaders.

For example:

- Depth/stencil-only rendering in a subpass with no color attachments

  - Active Pipeline Shader Stages

    - Vertex Shader

  - Required: Fixed-Function Pipeline Stages

    - VkPipelineVertexInputStateCreateInfo

    - VkPipelineInputAssemblyStateCreateInfo

    - VkPipelineViewportStateCreateInfo

    - VkPipelineRasterizationStateCreateInfo

    - VkPipelineMultisampleStateCreateInfo

    - VkPipelineDepthStencilStateCreateInfo

- Color-only rendering in a subpass with no depth/stencil attachment

  - Active Pipeline Shader Stages

    - Vertex Shader

    - Fragment Shader

  - Required: Fixed-Function Pipeline Stages

    - VkPipelineVertexInputStateCreateInfo

    - VkPipelineInputAssemblyStateCreateInfo

    - VkPipelineViewportStateCreateInfo

    - VkPipelineRasterizationStateCreateInfo

    - VkPipelineMultisampleStateCreateInfo

    - VkPipelineColorBlendStateCreateInfo

- Rendering pipeline with tessellation and geometry shaders

  - Active Pipeline Shader Stages

    - Vertex Shader

    - Tessellation Control Shader

    - Tessellation Evaluation Shader

    - Geometry Shader

    - Fragment Shader

  - Required: Fixed-Function Pipeline Stages

    - VkPipelineVertexInputStateCreateInfo

    - VkPipelineInputAssemblyStateCreateInfo

    - VkPipelineTessellationStateCreateInfo

    - VkPipelineViewportStateCreateInfo

    - VkPipelineRasterizationStateCreateInfo

    - VkPipelineMultisampleStateCreateInfo

    - VkPipelineDepthStencilStateCreateInfo

    - VkPipelineColorBlendStateCreateInfo

- Rendering pipeline with task and mesh shaders

  - Active Pipeline Shader Stages

    - Task Shader

    - Mesh Shader

    - Fragment Shader

  - Required: Fixed-Function Pipeline Stages

    - VkPipelineViewportStateCreateInfo

    - VkPipelineRasterizationStateCreateInfo

    - VkPipelineMultisampleStateCreateInfo

    - VkPipelineDepthStencilStateCreateInfo

    - VkPipelineColorBlendStateCreateInfo

#### 9.2.2. Graphics Pipeline Shader Groups

Graphics pipelines can contain multiple shader groups that can be bound individually. Each shader group behaves as if it was a pipeline using the shader group’s state. When the pipeline is bound by regular means, it behaves as if the state of group `0` is active, use vkCmdBindPipelineShaderGroupNV to bind an invidual shader group.

The primary purpose of shader groups is allowing the device to bind different pipeline state using Device-Generated Commands.

The `VkGraphicsPipelineShaderGroupsCreateInfoNV` structure is defined as:

    typedef struct VkGraphicsPipelineShaderGroupsCreateInfoNV {
        VkStructureType                             sType;
        const void*                                 pNext;
        uint32_t                                    groupCount;
        const VkGraphicsShaderGroupCreateInfoNV*    pGroups;
        uint32_t                                    pipelineCount;
        const VkPipeline*                           pPipelines;
    } VkGraphicsPipelineShaderGroupsCreateInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `groupCount` is the number of elements in the `pGroups` array.

- `pGroups` is an array of VkGraphicsShaderGroupCreateInfoNV values specifying which state of the original `VkGraphicsPipelineCreateInfo` each shader group overrides.

- `pipelineCount` is the number of elements in the `pPipelines` array.

- `pPipelines` is an array of graphics `VkPipeline`, which are referenced within the created pipeline, including all their shader groups.

When referencing shader groups by index, groups defined in the referenced pipelines are treated as if they were defined as additional entries in `pGroups`. They are appended in the order they appear in the `pPipelines` array and in the `pGroups` array when those pipelines were defined.

The application must maintain the lifetime of all such referenced pipelines based on the pipelines that make use of them.

Valid Usage

- `groupCount` must be at least `1` and as maximum `VkPhysicalDeviceDeviceGeneratedCommandsPropertiesNV`::`maxGraphicsShaderGroupCount`.

- The sum of `groupCount` including those groups added from referenced `pPipelines` must also be as maximum `VkPhysicalDeviceDeviceGeneratedCommandsPropertiesNV`::`maxGraphicsShaderGroupCount`.

- The state of the first element of `pGroups` must match its equivalent within the parent’s `VkGraphicsPipelineCreateInfo`.

- Each element of `pGroups` must in combination with the rest of the pipeline state yield a valid state configuration

- All elements of `pGroups` must use the same shader stage combinations unless any mesh shader stage is used, then either combination of task and mesh or just mesh shader is valid.

- Mesh and regular primitive shading stages cannot be mixed across `pGroups`.

- Each element of the `pPipelines` member of `libraries` must have been created with identical state to the pipeline currently created except the state that can be overriden by `VkGraphicsShaderGroupCreateInfoNV`.

- The `VkPhysicalDeviceDeviceGeneratedCommandsFeaturesNV`→`deviceGeneratedCommands` feature must be enabled

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_SHADER_GROUPS_CREATE_INFO_NV`

- `pGroups` must be a valid pointer to an array of `groupCount` valid VkGraphicsShaderGroupCreateInfoNV structures

- If `pipelineCount` is not `0`, `pPipelines` must be a valid pointer to an array of `pipelineCount` valid VkPipeline handles

- `groupCount` must be greater than `0`

The `VkGraphicsShaderGroupCreateInfoNV` structure provides the state overrides for each shader group. Each shader group behaves like a pipeline that was created from its state as well as the remaining parent’s state. It is defined as:

    typedef struct VkGraphicsShaderGroupCreateInfoNV {
        VkStructureType                                 sType;
        const void*                                     pNext;
        uint32_t                                        stageCount;
        const VkPipelineShaderStageCreateInfo*          pStages;
        const VkPipelineVertexInputStateCreateInfo*     pVertexInputState;
        const VkPipelineTessellationStateCreateInfo*    pTessellationState;
    } VkGraphicsShaderGroupCreateInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `stageCount` is the number of entries in the `pStages` array.

- `pStages` is an array of size `stageCount` structures of type VkPipelineShaderStageCreateInfo describing the set of the shader stages to be included in this shader group.

- `pVertexInputState` is a pointer to an instance of the VkPipelineVertexInputStateCreateInfo structure.

- `pTessellationState` is a pointer to an instance of the VkPipelineTessellationStateCreateInfo structure, and is ignored if the shader group does not include a tessellation control shader stage and tessellation evaluation shader stage.

Valid Usage

- For `stageCount`, the same restrictions as in `VkGraphicsPipelineCreateInfo`::`stageCount` apply.

- For `pStages`, the same restrictions as in `VkGraphicsPipelineCreateInfo`::`pStages` apply.

- For `pVertexInputState`, the same restrictions as in `VkGraphicsPipelineCreateInfo`::`pVertexInputState` apply.

- For `pTessellationState`, the same restrictions as in `VkGraphicsPipelineCreateInfo`::`pTessellationState` apply.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_GRAPHICS_SHADER_GROUP_CREATE_INFO_NV`

- `pNext` must be `NULL`

- `pStages` must be a valid pointer to an array of `stageCount` valid VkPipelineShaderStageCreateInfo structures

- `stageCount` must be greater than `0`

### 9.3. Pipeline destruction

To destroy a graphics or compute pipeline, call:

    void vkDestroyPipeline(
        VkDevice                                    device,
        VkPipeline                                  pipeline,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that destroys the pipeline.

- `pipeline` is the handle of the pipeline to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage

- All submitted commands that refer to `pipeline` must have completed execution

- If `VkAllocationCallbacks` were provided when `pipeline` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `pipeline` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `pipeline` is not VK_NULL_HANDLE, `pipeline` must be a valid VkPipeline handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- If `pipeline` is a valid handle, it must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `pipeline` must be externally synchronized

### 9.4. Multiple Pipeline Creation

Multiple pipelines can be created simultaneously by passing an array of `VkGraphicsPipelineCreateInfo` or `VkComputePipelineCreateInfo` structures into the vkCreateGraphicsPipelines and vkCreateComputePipelines commands, respectively. Applications can group together similar pipelines to be created in a single call, and implementations are encouraged to look for reuse opportunities within a group-create.

When an application attempts to create many pipelines in a single command, it is possible that some subset may fail creation. In that case, the corresponding entries in the `pPipelines` output array will be filled with VK_NULL_HANDLE values. If any pipeline fails creation (for example, due to out of memory errors), the `vkCreate*Pipelines` commands will return an error code. The implementation will attempt to create all pipelines, and only return VK_NULL_HANDLE values for those that actually failed.

If creation fails for a pipeline that had `VK_PIPELINE_CREATE_EARLY_RETURN_ON_FAILURE_BIT_EXT` set, pipelines at an index in the `pPipelines` array greater than or equal to that of the failing pipeline must be set to VK_NULL_HANDLE.

### 9.5. Pipeline Derivatives

A pipeline derivative is a child pipeline created from a parent pipeline, where the child and parent are expected to have much commonality. The goal of derivative pipelines is that they be cheaper to create using the parent as a starting point, and that it be more efficient (on either host or device) to switch/bind between children of the same parent.

A derivative pipeline is created by setting the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag in the `Vk*PipelineCreateInfo` structure. If this is set, then exactly one of `basePipelineHandle` or `basePipelineIndex` members of the structure must have a valid handle/index, and specifies the parent pipeline. If `basePipelineHandle` is used, the parent pipeline must have already been created. If `basePipelineIndex` is used, then the parent is being created in the same command. VK_NULL_HANDLE acts as the invalid handle for `basePipelineHandle`, and -1 is the invalid index for `basePipelineIndex`. If `basePipelineIndex` is used, the base pipeline must appear earlier in the array. The base pipeline must have been created with the `VK_PIPELINE_CREATE_ALLOW_DERIVATIVES_BIT` flag set.

### 9.6. Pipeline Cache

Pipeline cache objects allow the result of pipeline construction to be reused between pipelines and between runs of an application. Reuse between pipelines is achieved by passing the same pipeline cache object when creating multiple related pipelines. Reuse across runs of an application is achieved by retrieving pipeline cache contents in one run of an application, saving the contents, and using them to preinitialize a pipeline cache on a subsequent run. The contents of the pipeline cache objects are managed by the implementation. Applications can manage the host memory consumed by a pipeline cache object and control the amount of data retrieved from a pipeline cache object.

Pipeline cache objects are represented by `VkPipelineCache` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkPipelineCache)

To create pipeline cache objects, call:

    VkResult vkCreatePipelineCache(
        VkDevice                                    device,
        const VkPipelineCacheCreateInfo*            pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkPipelineCache*                            pPipelineCache);

- `device` is the logical device that creates the pipeline cache object.

- `pCreateInfo` is a pointer to a VkPipelineCacheCreateInfo structure containing initial parameters for the pipeline cache object.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pPipelineCache` is a pointer to a VkPipelineCache handle in which the resulting pipeline cache object is returned.

| Note Applications can track and manage the total host memory size of a pipeline cache object using the `pAllocator`. Applications can limit the amount of data retrieved from a pipeline cache object in `vkGetPipelineCacheData`. Implementations should not internally limit the total number of entries added to a pipeline cache object or the total host memory consumed.

Once created, a pipeline cache can be passed to the `vkCreateGraphicsPipelines` and `vkCreateComputePipelines` commands. If the pipeline cache passed into these commands is not VK_NULL_HANDLE, the implementation will query it for possible reuse opportunities and update it with new content. The use of the pipeline cache object in these commands is internally synchronized, and the same pipeline cache object can be used in multiple threads simultaneously.

If `flags` of `pCreateInfo` includes `VK_PIPELINE_CACHE_CREATE_EXTERNALLY_SYNCHRONIZED_BIT_EXT`, all commands that modify the returned pipeline cache object must be externally synchronized.

| Note Implementations should make every effort to limit any critical sections to the actual accesses to the cache, which is expected to be significantly shorter than the duration of the `vkCreateGraphicsPipelines` and `vkCreateComputePipelines` commands.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkPipelineCacheCreateInfo structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pPipelineCache` must be a valid pointer to a VkPipelineCache handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkPipelineCacheCreateInfo` structure is defined as:

    typedef struct VkPipelineCacheCreateInfo {
        VkStructureType               sType;
        const void*                   pNext;
        VkPipelineCacheCreateFlags    flags;
        size_t                        initialDataSize;
        const void*                   pInitialData;
    } VkPipelineCacheCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkPipelineCacheCreateFlagBits specifying the behavior of the pipeline cache.

- `initialDataSize` is the number of bytes in `pInitialData`. If `initialDataSize` is zero, the pipeline cache will initially be empty.

- `pInitialData` is a pointer to previously retrieved pipeline cache data. If the pipeline cache data is incompatible (as defined below) with the device, the pipeline cache will be initially empty. If `initialDataSize` is zero, `pInitialData` is ignored.

Valid Usage

- If `initialDataSize` is not `0`, it must be equal to the size of `pInitialData`, as returned by `vkGetPipelineCacheData` when `pInitialData` was originally retrieved

- If `initialDataSize` is not `0`, `pInitialData` must have been retrieved from a previous call to `vkGetPipelineCacheData`

- If the `pipelineCreationCacheControl` feature is not enabled, `flags` must not include `VK_PIPELINE_CACHE_CREATE_EXTERNALLY_SYNCHRONIZED_BIT_EXT`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_CACHE_CREATE_INFO`

- `pNext` must be `NULL`

- `flags` must be a valid combination of VkPipelineCacheCreateFlagBits values

- If `initialDataSize` is not `0`, `pInitialData` must be a valid pointer to an array of `initialDataSize` bytes

    typedef VkFlags VkPipelineCacheCreateFlags;

`VkPipelineCacheCreateFlags` is a bitmask type for setting a mask of zero or more VkPipelineCacheCreateFlagBits.

Possible values of the `flags` member of VkPipelineCacheCreateInfo, specifying the behavior of the pipeline cache, are:

    typedef enum VkPipelineCacheCreateFlagBits {
        VK_PIPELINE_CACHE_CREATE_EXTERNALLY_SYNCHRONIZED_BIT_EXT = 0x00000001,
        VK_PIPELINE_CACHE_CREATE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkPipelineCacheCreateFlagBits;

- `VK_PIPELINE_CACHE_CREATE_EXTERNALLY_SYNCHRONIZED_BIT_EXT` specifies that all commands that modify the created VkPipelineCache will be externally synchronized. When set, the implementation may skip any unnecessary processing needed to support simultaneous modification from multiple threads where allowed.

Pipeline cache objects can be merged using the command:

    VkResult vkMergePipelineCaches(
        VkDevice                                    device,
        VkPipelineCache                             dstCache,
        uint32_t                                    srcCacheCount,
        const VkPipelineCache*                      pSrcCaches);

- `device` is the logical device that owns the pipeline cache objects.

- `dstCache` is the handle of the pipeline cache to merge results into.

- `srcCacheCount` is the length of the `pSrcCaches` array.

- `pSrcCaches` is a pointer to an array of pipeline cache handles, which will be merged into `dstCache`. The previous contents of `dstCache` are included after the merge.

| Note The details of the merge operation are implementation dependent, but implementations should merge the contents of the specified pipelines and prune duplicate entries.

Valid Usage

- `dstCache` must not appear in the list of source caches

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `dstCache` must be a valid VkPipelineCache handle

- `pSrcCaches` must be a valid pointer to an array of `srcCacheCount` valid VkPipelineCache handles

- `srcCacheCount` must be greater than `0`

- `dstCache` must have been created, allocated, or retrieved from `device`

- Each element of `pSrcCaches` must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `dstCache` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

Data can be retrieved from a pipeline cache object using the command:

    VkResult vkGetPipelineCacheData(
        VkDevice                                    device,
        VkPipelineCache                             pipelineCache,
        size_t*                                     pDataSize,
        void*                                       pData);

- `device` is the logical device that owns the pipeline cache.

- `pipelineCache` is the pipeline cache to retrieve data from.

- `pDataSize` is a pointer to a `size_t` value related to the amount of data in the pipeline cache, as described below.

- `pData` is either `NULL` or a pointer to a buffer.

If `pData` is `NULL`, then the maximum size of the data that can be retrieved from the pipeline cache, in bytes, is returned in `pDataSize`. Otherwise, `pDataSize` must point to a variable set by the user to the size of the buffer, in bytes, pointed to by `pData`, and on return the variable is overwritten with the amount of data actually written to `pData`.

If `pDataSize` is less than the maximum size that can be retrieved by the pipeline cache, at most `pDataSize` bytes will be written to `pData`, and `vkGetPipelineCacheData` will return `VK_INCOMPLETE`. Any data written to `pData` is valid and can be provided as the `pInitialData` member of the `VkPipelineCacheCreateInfo` structure passed to `vkCreatePipelineCache`.

Two calls to `vkGetPipelineCacheData` with the same parameters must retrieve the same data unless a command that modifies the contents of the cache is called between them.

Applications can store the data retrieved from the pipeline cache, and use these data, possibly in a future run of the application, to populate new pipeline cache objects. The results of pipeline compiles, however, may depend on the vendor ID, device ID, driver version, and other details of the device. To enable applications to detect when previously retrieved data is incompatible with the device, the initial bytes written to `pData` must be a header consisting of the following members:

Table 12. Layout for pipeline cache header version `VK_PIPELINE_CACHE_HEADER_VERSION_ONE`
Offset | Size | Meaning
--- | --- | ---
0 | 4 | length in bytes of the entire pipeline cache header written as a stream of bytes, with the least significant byte first
4 | 4 | a VkPipelineCacheHeaderVersion value written as a stream of bytes, with the least significant byte first
8 | 4 | a vendor ID equal to `VkPhysicalDeviceProperties`::`vendorID` written as a stream of bytes, with the least significant byte first
12 | 4 | a device ID equal to `VkPhysicalDeviceProperties`::`deviceID` written as a stream of bytes, with the least significant byte first
16 | `VK_UUID_SIZE` | a pipeline cache ID equal to `VkPhysicalDeviceProperties`::`pipelineCacheUUID`

The first four bytes encode the length of the entire pipeline cache header, in bytes. This value includes all fields in the header including the pipeline cache version field and the size of the length field.

The next four bytes encode the pipeline cache version, as described for VkPipelineCacheHeaderVersion. A consumer of the pipeline cache should use the cache version to interpret the remainder of the cache header.

If `pDataSize` is less than what is necessary to store this header, nothing will be written to `pData` and zero will be written to `pDataSize`.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pipelineCache` must be a valid VkPipelineCache handle

- `pDataSize` must be a valid pointer to a `size_t` value

- If the value referenced by `pDataSize` is not `0`, and `pData` is not `NULL`, `pData` must be a valid pointer to an array of `pDataSize` bytes

- `pipelineCache` must have been created, allocated, or retrieved from `device`

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

Possible values of the second group of four bytes in the header returned by vkGetPipelineCacheData, encoding the pipeline cache version, are:

    typedef enum VkPipelineCacheHeaderVersion {
        VK_PIPELINE_CACHE_HEADER_VERSION_ONE = 1,
        VK_PIPELINE_CACHE_HEADER_VERSION_MAX_ENUM = 0x7FFFFFFF
    } VkPipelineCacheHeaderVersion;

- `VK_PIPELINE_CACHE_HEADER_VERSION_ONE` specifies version one of the pipeline cache.

To destroy a pipeline cache, call:

    void vkDestroyPipelineCache(
        VkDevice                                    device,
        VkPipelineCache                             pipelineCache,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that destroys the pipeline cache object.

- `pipelineCache` is the handle of the pipeline cache to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage

- If `VkAllocationCallbacks` were provided when `pipelineCache` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `pipelineCache` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `pipelineCache` is not VK_NULL_HANDLE, `pipelineCache` must be a valid VkPipelineCache handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- If `pipelineCache` is a valid handle, it must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `pipelineCache` must be externally synchronized

### 9.7. Specialization Constants

Specialization constants are a mechanism whereby constants in a SPIR-V module can have their constant value specified at the time the `VkPipeline` is created. This allows a SPIR-V module to have constants that can be modified while executing an application that uses the Vulkan API.

| Note Specialization constants are useful to allow a compute shader to have its local workgroup size changed at runtime by the user, for example.

Each `VkPipelineShaderStageCreateInfo` structure contains a `pSpecializationInfo` member, which can be `NULL` to indicate no specialization constants, or point to a `VkSpecializationInfo` structure.

The `VkSpecializationInfo` structure is defined as:

    typedef struct VkSpecializationInfo {
        uint32_t                           mapEntryCount;
        const VkSpecializationMapEntry*    pMapEntries;
        size_t                             dataSize;
        const void*                        pData;
    } VkSpecializationInfo;

- `mapEntryCount` is the number of entries in the `pMapEntries` array.

- `pMapEntries` is a pointer to an array of `VkSpecializationMapEntry` structures which map constant IDs to offsets in `pData`.

- `dataSize` is the byte size of the `pData` buffer.

- `pData` contains the actual constant values to specialize with.

`pMapEntries` is a pointer to a VkSpecializationMapEntry structure.

Valid Usage

- The `offset` member of each element of `pMapEntries` must be less than `dataSize`

- The `size` member of each element of `pMapEntries` must be less than or equal to `dataSize` minus `offset`

Valid Usage (Implicit)

- If `mapEntryCount` is not `0`, `pMapEntries` must be a valid pointer to an array of `mapEntryCount` valid VkSpecializationMapEntry structures

- If `dataSize` is not `0`, `pData` must be a valid pointer to an array of `dataSize` bytes

The `VkSpecializationMapEntry` structure is defined as:

    typedef struct VkSpecializationMapEntry {
        uint32_t    constantID;
        uint32_t    offset;
        size_t      size;
    } VkSpecializationMapEntry;

- `constantID` is the ID of the specialization constant in SPIR-V.

- `offset` is the byte offset of the specialization constant value within the supplied data buffer.

- `size` is the byte size of the specialization constant value within the supplied data buffer.

If a `constantID` value is not a specialization constant ID used in the shader, that map entry does not affect the behavior of the pipeline.

Valid Usage

- For a `constantID` specialization constant declared in a shader, `size` must match the byte size of the `constantID`. If the specialization constant is of type `boolean`, `size` must be the byte size of `VkBool32`

In human readable SPIR-V:

    OpDecorate %x SpecId 13 ; decorate .x component of WorkgroupSize with ID 13
    OpDecorate %y SpecId 42 ; decorate .y component of WorkgroupSize with ID 42
    OpDecorate %z SpecId 3  ; decorate .z component of WorkgroupSize with ID 3
    OpDecorate %wgsize BuiltIn WorkgroupSize ; decorate WorkgroupSize onto constant
    %i32 = OpTypeInt 32 0 ; declare an unsigned 32-bit type
    %uvec3 = OpTypeVector %i32 3 ; declare a 3 element vector type of unsigned 32-bit
    %x = OpSpecConstant %i32 1 ; declare the .x component of WorkgroupSize
    %y = OpSpecConstant %i32 1 ; declare the .y component of WorkgroupSize
    %z = OpSpecConstant %i32 1 ; declare the .z component of WorkgroupSize
    %wgsize = OpSpecConstantComposite %uvec3 %x %y %z ; declare WorkgroupSize

From the above we have three specialization constants, one for each of the x, y & z elements of the WorkgroupSize vector.

Now to specialize the above via the specialization constants mechanism:

    const VkSpecializationMapEntry entries[] =
    {
        {
            13,                             // constantID
            0 * sizeof(uint32_t),           // offset
            sizeof(uint32_t)                // size
        },
        {
            42,                             // constantID
            1 * sizeof(uint32_t),           // offset
            sizeof(uint32_t)                // size
        },
        {
            3,                              // constantID
            2 * sizeof(uint32_t),           // offset
            sizeof(uint32_t)                // size
        }
    };

    const uint32_t data[] = { 16, 8, 4 }; // our workgroup size is 16x8x4

    const VkSpecializationInfo info =
    {
        3,                                  // mapEntryCount
        entries,                            // pMapEntries
        3 * sizeof(uint32_t),               // dataSize
        data,                               // pData
    };

Then when calling vkCreateComputePipelines, and passing the `VkSpecializationInfo` we defined as the `pSpecializationInfo` parameter of VkPipelineShaderStageCreateInfo, we will create a compute pipeline with the runtime specified local workgroup size.

Another example would be that an application has a SPIR-V module that has some platform-dependent constants they wish to use.

In human readable SPIR-V:

    OpDecorate %1 SpecId 0  ; decorate our signed 32-bit integer constant
    OpDecorate %2 SpecId 12 ; decorate our 32-bit floating-point constant
    %i32 = OpTypeInt 32 1   ; declare a signed 32-bit type
    %float = OpTypeFloat 32 ; declare a 32-bit floating-point type
    %1 = OpSpecConstant %i32 -1 ; some signed 32-bit integer constant
    %2 = OpSpecConstant %float 0.5 ; some 32-bit floating-point constant

From the above we have two specialization constants, one is a signed 32-bit integer and the second is a 32-bit floating-point.

Now to specialize the above via the specialization constants mechanism:

    struct SpecializationData {
        int32_t data0;
        float data1;
    };

    const VkSpecializationMapEntry entries[] =
    {
        {
            0,                                    // constantID
            offsetof(SpecializationData, data0),  // offset
            sizeof(SpecializationData::data0)     // size
        },
        {
            12,                                   // constantID
            offsetof(SpecializationData, data1),  // offset
            sizeof(SpecializationData::data1)     // size
        }
    };

    SpecializationData data;
    data.data0 = -42;    // set the data for the 32-bit integer
    data.data1 = 42.0f;  // set the data for the 32-bit floating-point

    const VkSpecializationInfo info =
    {
        2,                                  // mapEntryCount
        entries,                            // pMapEntries
        sizeof(data),                       // dataSize
        &data,                              // pData
    };

It is legal for a SPIR-V module with specializations to be compiled into a pipeline where no specialization info was provided. SPIR-V specialization constants contain default values such that if a specialization is not provided, the default value will be used. In the examples above, it would be valid for an application to only specialize some of the specialization constants within the SPIR-V module, and let the other constants use their default values encoded within the OpSpecConstant declarations.

### 9.8. Pipeline Libraries

A pipeline library is a special pipeline that was created using the `VK_PIPELINE_CREATE_LIBRARY_BIT_KHR` and cannot be bound, instead it defines a set of pipeline state which can be linked into other pipelines. For ray tracing pipelines this includes shaders and shader groups. The application must maintain the lifetime of pipeline libraries based on the pipelines that link with it. A pipeline library is considered in-use, as long as one of the linking pipelines is in-use.

This linkage is achieved by using the following structure within the appropriate creation mechanisms:

The `VkPipelineLibraryCreateInfoKHR` structure is defined as:

    typedef struct VkPipelineLibraryCreateInfoKHR {
        VkStructureType      sType;
        const void*          pNext;
        uint32_t             libraryCount;
        const VkPipeline*    pLibraries;
    } VkPipelineLibraryCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `libraryCount` is the number of pipeline libraries in `pLibraries`.

- `pLibraries` is an array of pipeline libraries to use when creating a pipeline.

Valid Usage

- Each element of `pLibraries` must have been created with `VK_PIPELINE_CREATE_LIBRARY_BIT_KHR`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_LIBRARY_CREATE_INFO_KHR`

- `pNext` must be `NULL`

- If `libraryCount` is not `0`, `pLibraries` must be a valid pointer to an array of `libraryCount` valid VkPipeline handles

### 9.9. Pipeline Binding

Once a pipeline has been created, it can be bound to the command buffer using the command:

    void vkCmdBindPipeline(
        VkCommandBuffer                             commandBuffer,
        VkPipelineBindPoint                         pipelineBindPoint,
        VkPipeline                                  pipeline);

- `commandBuffer` is the command buffer that the pipeline will be bound to.

- `pipelineBindPoint` is a VkPipelineBindPoint value specifying whether to bind to the compute or graphics bind point. Binding one does not disturb the other.

- `pipeline` is the pipeline to be bound.

Once bound, a pipeline binding affects subsequent graphics or compute commands in the command buffer until a different pipeline is bound to the bind point. The pipeline bound to `VK_PIPELINE_BIND_POINT_COMPUTE` controls the behavior of vkCmdDispatch and vkCmdDispatchIndirect. The pipeline bound to `VK_PIPELINE_BIND_POINT_GRAPHICS` controls the behavior of all drawing commands. The pipeline bound to `VK_PIPELINE_BIND_POINT_RAY_TRACING_KHR` controls the behavior of vkCmdTraceRaysKHR. No other commands are affected by the pipeline state.

Valid Usage

- If `pipelineBindPoint` is `VK_PIPELINE_BIND_POINT_COMPUTE`, the `VkCommandPool` that `commandBuffer` was allocated from must support compute operations

- If `pipelineBindPoint` is `VK_PIPELINE_BIND_POINT_GRAPHICS`, the `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- If `pipelineBindPoint` is `VK_PIPELINE_BIND_POINT_COMPUTE`, `pipeline` must be a compute pipeline

- If `pipelineBindPoint` is `VK_PIPELINE_BIND_POINT_GRAPHICS`, `pipeline` must be a graphics pipeline

- If the variable multisample rate feature is not supported, `pipeline` is a graphics pipeline, the current subpass has no attachments, and this is not the first call to this function with a graphics pipeline after transitioning to the current subpass, then the sample count specified by this pipeline must match that set in the previous pipeline

- If VkPhysicalDeviceSampleLocationsPropertiesEXT::`variableSampleLocations` is `VK_FALSE`, and `pipeline` is a graphics pipeline created with a VkPipelineSampleLocationsStateCreateInfoEXT structure having its `sampleLocationsEnable` member set to `VK_TRUE` but without `VK_DYNAMIC_STATE_SAMPLE_LOCATIONS_EXT` enabled then the current render pass instance must have been begun by specifying a VkRenderPassSampleLocationsBeginInfoEXT structure whose `pPostSubpassSampleLocations` member contains an element with a `subpassIndex` matching the current subpass index and the `sampleLocationsInfo` member of that element must match the `sampleLocationsInfo` specified in VkPipelineSampleLocationsStateCreateInfoEXT when the pipeline was created

- This command must not be recorded when transform feedback is active

- If `pipelineBindPoint` is `VK_PIPELINE_BIND_POINT_RAY_TRACING_KHR`, the `VkCommandPool` that `commandBuffer` was allocated from must support compute operations

- If `pipelineBindPoint` is `VK_PIPELINE_BIND_POINT_RAY_TRACING_KHR`, the `pipeline` must be a ray tracing pipeline

- The `pipeline` must not have been created with `VK_PIPELINE_CREATE_LIBRARY_BIT_KHR` set.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pipelineBindPoint` must be a valid VkPipelineBindPoint value

- `pipeline` must be a valid VkPipeline handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

- Both of `commandBuffer`, and `pipeline` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute |

Possible values of vkCmdBindPipeline::`pipelineBindPoint`, specifying the bind point of a pipeline object, are:

    typedef enum VkPipelineBindPoint {
        VK_PIPELINE_BIND_POINT_GRAPHICS = 0,
        VK_PIPELINE_BIND_POINT_COMPUTE = 1,
        VK_PIPELINE_BIND_POINT_RAY_TRACING_KHR = 1000165000,
        VK_PIPELINE_BIND_POINT_RAY_TRACING_NV = VK_PIPELINE_BIND_POINT_RAY_TRACING_KHR,
        VK_PIPELINE_BIND_POINT_MAX_ENUM = 0x7FFFFFFF
    } VkPipelineBindPoint;

- `VK_PIPELINE_BIND_POINT_COMPUTE` specifies binding as a compute pipeline.

- `VK_PIPELINE_BIND_POINT_GRAPHICS` specifies binding as a graphics pipeline.

- `VK_PIPELINE_BIND_POINT_RAY_TRACING_KHR` specifies binding as a ray tracing pipeline.

For pipelines that were created with the support of multiple shader groups (see Graphics Pipeline Shader Groups), the regular `vkCmdBindPipeline` command will bind Shader Group `0`. To explicitly bind a shader group use:

    void vkCmdBindPipelineShaderGroupNV(
        VkCommandBuffer                             commandBuffer,
        VkPipelineBindPoint                         pipelineBindPoint,
        VkPipeline                                  pipeline,
        uint32_t                                    groupIndex);

- `commandBuffer` is the command buffer that the pipeline will be bound to.

- `pipelineBindPoint` is a VkPipelineBindPoint value specifying to which bind point the pipeline is bound.

- `pipeline` is the pipeline to be bound.

- `groupIndex` is the shader group to be bound.

Valid Usage

- `groupIndex` must be `0` or less than the effective VkGraphicsPipelineShaderGroupsCreateInfoNV::`groupCount` including the referenced pipelines.

- The `pipelineBindPoint` must be `VK_PIPELINE_BIND_POINT_GRAPHICS`

- The same restrictions as vkCmdBindPipeline apply as if the bound pipeline was created only with the Shader Group from the `groupIndex` information.

- The `VkPhysicalDeviceDeviceGeneratedCommandsFeaturesNV`→`deviceGeneratedCommands` feature must be enabled

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pipelineBindPoint` must be a valid VkPipelineBindPoint value

- `pipeline` must be a valid VkPipeline handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

- Both of `commandBuffer`, and `pipeline` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute |

### 9.10. Dynamic State

When a pipeline object is bound, any pipeline object state that is not specified as dynamic is applied to the command buffer state. Pipeline object state that is specified as dynamic is not applied to the command buffer state at this time. Instead, dynamic state can be modified at any time and persists for the lifetime of the command buffer, or until modified by another dynamic state setting command or another pipeline bind.

When a pipeline object is bound, the following applies to each state parameter:

- If the state is not specified as dynamic in the new pipeline object, then that command buffer state is overwritten by the state in the new pipeline object. Before any draw or dispatch call with this pipeline there must not have been any call to any of the corresponding dynamic state setting commands after this pipeline was bound

- If the state is specified as dynamic in the new pipeline object, then that command buffer state is not disturbed. Before any draw or dispatch call with this pipeline there must have been at least one call to each of the corresponding dynamic state setting commands since the command buffer recording was begun, or the last bound pipeline object with that state specified as static, whichever was the latter

Dynamic state that does not affect the result of operations can be left undefined.

| Note For example, if blending is disabled by the pipeline object state then the dynamic color blend constants do not need to be specified in the command buffer, even if this state is specified as dynamic in the pipeline object.

### 9.11. Pipeline Shader Information

When a pipeline is created, its state and shaders are compiled into zero or more device-specific executables, which are used when executing commands against that pipeline. To query the properties of these executables, call:

    VkResult vkGetPipelineExecutablePropertiesKHR(
        VkDevice                                    device,
        const VkPipelineInfoKHR*                    pPipelineInfo,
        uint32_t*                                   pExecutableCount,
        VkPipelineExecutablePropertiesKHR*          pProperties);

- `device` is the device that created the pipeline.

- `pPipelineInfo` describes the pipeline being queried.

- `pExecutableCount` is a pointer to an integer related to the number of pipeline executables available or queried, as described below.

- `pProperties` is either `NULL` or a pointer to an array of VkPipelineExecutablePropertiesKHR structures.

If `pProperties` is `NULL`, then the number of executables associated with the pipeline is returned in `pExecutableCount`. Otherwise, `pExecutableCount` must point to a variable set by the user to the number of elements in the `pProperties` array, and on return the variable is overwritten with the number of structures actually written to `pProperties`. If `pExecutableCount` is less than the number of executables associated with the pipeline, at most `pExecutableCount` structures will be written and `vkGetPipelineExecutablePropertiesKHR` will return `VK_INCOMPLETE`.

Valid Usage

- `pipelineExecutableInfo` must be enabled.

- `pipeline` member of `pPipelineInfo` must have been created with `device`.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pPipelineInfo` must be a valid pointer to a valid VkPipelineInfoKHR structure

- `pExecutableCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pExecutableCount` is not `0`, and `pProperties` is not `NULL`, `pProperties` must be a valid pointer to an array of `pExecutableCount` VkPipelineExecutablePropertiesKHR structures

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkPipelineInfoKHR` structure is defined as:

    typedef struct VkPipelineInfoKHR {
        VkStructureType    sType;
        const void*        pNext;
        VkPipeline         pipeline;
    } VkPipelineInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `pipeline` is a `VkPipeline` handle.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_INFO_KHR`

- `pNext` must be `NULL`

- `pipeline` must be a valid VkPipeline handle

The `VkPipelineExecutablePropertiesKHR` structure is defined as:

    typedef struct VkPipelineExecutablePropertiesKHR {
        VkStructureType       sType;
        void*                 pNext;
        VkShaderStageFlags    stages;
        char                  name[VK_MAX_DESCRIPTION_SIZE];
        char                  description[VK_MAX_DESCRIPTION_SIZE];
        uint32_t              subgroupSize;
    } VkPipelineExecutablePropertiesKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `stages` is a bitmask of VkShaderStageFlagBits indicating which shader stages (if any) were principally used as inputs to compile this pipeline executable.

- `name` is an array of `VK_MAX_DESCRIPTION_SIZE` `char` containing a null-terminated UTF-8 string which is a short human readable name for this executable.

- `description` is an array of `VK_MAX_DESCRIPTION_SIZE` `char` containing a null-terminated UTF-8 string which is a human readable description for this executable.

- `subgroupSize` is the subgroup size with which this executable is dispatched.

The `stages` field may be zero or it may contain one or more bits describing the stages principally used to compile this pipeline. Not all implementations have a 1:1 mapping between shader stages and pipeline executables and some implementations may reduce a given shader stage to fixed function hardware programming such that no executable is available. No guarantees are provided about the mapping between shader stages and pipeline executables and `stages` should be considered a best effort hint. Because the application cannot rely on the `stages` field to provide an exact description, `name` and `description` provide a human readable name and description which more accurately describes the given pipeline executable.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_EXECUTABLE_PROPERTIES_KHR`

- `pNext` must be `NULL`

Each pipeline executable may have a set of statistics associated with it that are generated by the pipeline compilation process. These statistics may include things such as instruction counts, amount of spilling (if any), maximum number of simultaneous threads, or anything else which may aid developers in evaluating the expected performance of a shader. To query the compile-time statistics associated with a pipeline executable, call:

    VkResult vkGetPipelineExecutableStatisticsKHR(
        VkDevice                                    device,
        const VkPipelineExecutableInfoKHR*          pExecutableInfo,
        uint32_t*                                   pStatisticCount,
        VkPipelineExecutableStatisticKHR*           pStatistics);

- `device` is the device that created the pipeline.

- `pExecutableInfo` describes the pipeline executable being queried.

- `pStatisticCount` is a pointer to an integer related to the number of statistics available or queried, as described below.

- `pStatistics` is either `NULL` or a pointer to an array of VkPipelineExecutableStatisticKHR structures.

If `pStatistics` is `NULL`, then the number of statistics associated with the pipeline executable is returned in `pStatisticCount`. Otherwise, `pStatisticCount` must point to a variable set by the user to the number of elements in the `pStatistics` array, and on return the variable is overwritten with the number of structures actually written to `pStatistics`. If `pStatisticCount` is less than the number of statistics associated with the pipeline executable, at most `pStatisticCount` structures will be written and `vkGetPipelineExecutableStatisticsKHR` will return `VK_INCOMPLETE`.

Valid Usage

- `pipelineExecutableInfo` must be enabled.

- `pipeline` member of `pExecutableInfo` must have been created with `device`.

- `pipeline` member of `pExecutableInfo` must have been created with `VK_PIPELINE_CREATE_CAPTURE_STATISTICS_BIT_KHR` set in the `flags` field of VkGraphicsPipelineCreateInfo or VkComputePipelineCreateInfo.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pExecutableInfo` must be a valid pointer to a valid VkPipelineExecutableInfoKHR structure

- `pStatisticCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pStatisticCount` is not `0`, and `pStatistics` is not `NULL`, `pStatistics` must be a valid pointer to an array of `pStatisticCount` VkPipelineExecutableStatisticKHR structures

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkPipelineExecutableInfoKHR` structure is defined as:

    typedef struct VkPipelineExecutableInfoKHR {
        VkStructureType    sType;
        const void*        pNext;
        VkPipeline         pipeline;
        uint32_t           executableIndex;
    } VkPipelineExecutableInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `pipeline` is the pipeline to query.

- `executableIndex` is the index of the executable to query in the array of executable properties returned by vkGetPipelineExecutablePropertiesKHR.

Valid Usage

- `executableIndex` must be less than the number of executables associated with `pipeline` as returned in the `pExecutableCount` parameter of `vkGetPipelineExecutablePropertiesKHR`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_EXECUTABLE_INFO_KHR`

- `pNext` must be `NULL`

- `pipeline` must be a valid VkPipeline handle

The `VkPipelineExecutableStatisticKHR` structure is defined as:

    typedef struct VkPipelineExecutableStatisticKHR {
        VkStructureType                           sType;
        void*                                     pNext;
        char                                      name[VK_MAX_DESCRIPTION_SIZE];
        char                                      description[VK_MAX_DESCRIPTION_SIZE];
        VkPipelineExecutableStatisticFormatKHR    format;
        VkPipelineExecutableStatisticValueKHR     value;
    } VkPipelineExecutableStatisticKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `name` is an array of `VK_MAX_DESCRIPTION_SIZE` `char` containing a null-terminated UTF-8 string which is a short human readable name for this statistic.

- `description` is an array of `VK_MAX_DESCRIPTION_SIZE` `char` containing a null-terminated UTF-8 string which is a human readable description for this statistic.

- `format` is a VkPipelineExecutableStatisticFormatKHR value specifying the format of the data found in `value`.

- `value` is the value of this statistic.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_EXECUTABLE_STATISTIC_KHR`

- `pNext` must be `NULL`

The `VkPipelineExecutableStatisticFormatKHR` enum is defined as:

    typedef enum VkPipelineExecutableStatisticFormatKHR {
        VK_PIPELINE_EXECUTABLE_STATISTIC_FORMAT_BOOL32_KHR = 0,
        VK_PIPELINE_EXECUTABLE_STATISTIC_FORMAT_INT64_KHR = 1,
        VK_PIPELINE_EXECUTABLE_STATISTIC_FORMAT_UINT64_KHR = 2,
        VK_PIPELINE_EXECUTABLE_STATISTIC_FORMAT_FLOAT64_KHR = 3,
        VK_PIPELINE_EXECUTABLE_STATISTIC_FORMAT_MAX_ENUM_KHR = 0x7FFFFFFF
    } VkPipelineExecutableStatisticFormatKHR;

- `VK_PIPELINE_EXECUTABLE_STATISTIC_FORMAT_BOOL32_KHR` specifies that the statistic is returned as a 32-bit boolean value which must be either `VK_TRUE` or `VK_FALSE` and should be read from the `b32` field of `VkPipelineExecutableStatisticValueKHR`.

- `VK_PIPELINE_EXECUTABLE_STATISTIC_FORMAT_INT64_KHR` specifies that the statistic is returned as a signed 64-bit integer and should be read from the `i64` field of `VkPipelineExecutableStatisticValueKHR`.

- `VK_PIPELINE_EXECUTABLE_STATISTIC_FORMAT_UINT64_KHR` specifies that the statistic is returned as an unsigned 64-bit integer and should be read from the `u64` field of `VkPipelineExecutableStatisticValueKHR`.

- `VK_PIPELINE_EXECUTABLE_STATISTIC_FORMAT_FLOAT64_KHR` specifies that the statistic is returned as a 64-bit floating-point value and should be read from the `f64` field of `VkPipelineExecutableStatisticValueKHR`.

The `VkPipelineExecutableStatisticValueKHR` union is defined as:

    typedef union VkPipelineExecutableStatisticValueKHR {
        VkBool32    b32;
        int64_t     i64;
        uint64_t    u64;
        double      f64;
    } VkPipelineExecutableStatisticValueKHR;

- `b32` is the 32-bit boolean value if the `VkPipelineExecutableStatisticFormatKHR` is `VK_PIPELINE_EXECUTABLE_STATISTIC_FORMAT_BOOL32_KHR`.

- `i64` is the signed 64-bit integer value if the `VkPipelineExecutableStatisticFormatKHR` is `VK_PIPELINE_EXECUTABLE_STATISTIC_FORMAT_INT64_KHR`.

- `u64` is the unsigned 64-bit integer value if the `VkPipelineExecutableStatisticFormatKHR` is `VK_PIPELINE_EXECUTABLE_STATISTIC_FORMAT_UINT64_KHR`.

- `f64` is the 64-bit floating-point value if the `VkPipelineExecutableStatisticFormatKHR` is `VK_PIPELINE_EXECUTABLE_STATISTIC_FORMAT_FLOAT64_KHR`.

Each pipeline executable may have one or more text or binary internal representations associated with it which are generated as part of the compile process. These may include the final shader assembly, a binary form of the compiled shader, or the shader compiler’s internal representation at any number of intermediate compile steps. To query the internal representations associated with a pipeline executable, call:

    VkResult vkGetPipelineExecutableInternalRepresentationsKHR(
        VkDevice                                    device,
        const VkPipelineExecutableInfoKHR*          pExecutableInfo,
        uint32_t*                                   pInternalRepresentationCount,
        VkPipelineExecutableInternalRepresentationKHR* pInternalRepresentations);

- `device` is the device that created the pipeline.

- `pExecutableInfo` describes the pipeline executable being queried.

- `pInternalRepresentationCount` is a pointer to an integer related to the number of internal representations available or queried, as described below.

- `pInternalRepresentations` is either `NULL` or a pointer to an array of VkPipelineExecutableInternalRepresentationKHR structures.

If `pInternalRepresentations` is `NULL`, then the number of internal representations associated with the pipeline executable is returned in `pInternalRepresentationCount`. Otherwise, `pInternalRepresentationCount` must point to a variable set by the user to the number of elements in the `pInternalRepresentations` array, and on return the variable is overwritten with the number of structures actually written to `pInternalRepresentations`. If `pInternalRepresentationCount` is less than the number of internal representations associated with the pipeline executable, at most `pInternalRepresentationCount` structures will be written and `vkGetPipelineExecutableInternalRepresentationsKHR` will return `VK_INCOMPLETE`.

While the details of the internal representations remain implementation dependent, the implementation should order the internal representations in the order in which they occur in the compile pipeline with the final shader assembly (if any) last.

Valid Usage

- `pipelineExecutableInfo` must be enabled.

- `pipeline` member of `pExecutableInfo` must have been created with `device`.

- `pipeline` member of `pExecutableInfo` must have been created with `VK_PIPELINE_CREATE_CAPTURE_INTERNAL_REPRESENTATIONS_BIT_KHR` set in the `flags` field of VkGraphicsPipelineCreateInfo or VkComputePipelineCreateInfo.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pExecutableInfo` must be a valid pointer to a valid VkPipelineExecutableInfoKHR structure

- `pInternalRepresentationCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pInternalRepresentationCount` is not `0`, and `pInternalRepresentations` is not `NULL`, `pInternalRepresentations` must be a valid pointer to an array of `pInternalRepresentationCount` VkPipelineExecutableInternalRepresentationKHR structures

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkPipelineExecutableInternalRepresentationKHR` structure is defined as:

    typedef struct VkPipelineExecutableInternalRepresentationKHR {
        VkStructureType    sType;
        void*              pNext;
        char               name[VK_MAX_DESCRIPTION_SIZE];
        char               description[VK_MAX_DESCRIPTION_SIZE];
        VkBool32           isText;
        size_t             dataSize;
        void*              pData;
    } VkPipelineExecutableInternalRepresentationKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `name` is an array of `VK_MAX_DESCRIPTION_SIZE` `char` containing a null-terminated UTF-8 string which is a short human readable name for this internal representation.

- `description` is an array of `VK_MAX_DESCRIPTION_SIZE` `char` containing a null-terminated UTF-8 string which is a human readable description for this internal representation.

- `isText` specifies whether the returned data is text or opaque data. If `isText` is `VK_TRUE` then the data returned in `pData` is text and is guaranteed to be a null-terminated UTF-8 string.

- `dataSize` is an integer related to the size, in bytes, of the internal representation data, as described below.

- `pData` is either `NULL` or a pointer to an block of data into which the implementation will write the textual form of the internal representation.

If `pData` is `NULL`, then the size, in bytes, of the internal representation data is returned in `dataSize`. Otherwise, `dataSize` must be the size of the buffer, in bytes, pointed to by `pData` and on return `dataSize` is overwritten with the number of bytes of data actually written to `pData` including any trailing null character. If `dataSize` is less than the size, in bytes, of the internal representation data, at most `dataSize` bytes of data will be written to `pData` and `vkGetPipelineExecutableInternalRepresentationsKHR` will return `VK_INCOMPLETE`. If `isText` is `VK_TRUE` and `pData` is not `NULL` and `dataSize` is not zero, the last byte written to `pData` will be a null character.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_EXECUTABLE_INTERNAL_REPRESENTATION_KHR`

- `pNext` must be `NULL`

Information about a particular shader that has been compiled as part of a pipeline object can be extracted by calling:

    VkResult vkGetShaderInfoAMD(
        VkDevice                                    device,
        VkPipeline                                  pipeline,
        VkShaderStageFlagBits                       shaderStage,
        VkShaderInfoTypeAMD                         infoType,
        size_t*                                     pInfoSize,
        void*                                       pInfo);

- `device` is the device that created `pipeline`.

- `pipeline` is the target of the query.

- `shaderStage` identifies the particular shader within the pipeline about which information is being queried.

- `infoType` describes what kind of information is being queried.

- `pInfoSize` is a pointer to a value related to the amount of data the query returns, as described below.

- `pInfo` is either NULL or a pointer to a buffer.

If `pInfo` is `NULL`, then the maximum size of the information that can be retrieved about the shader, in bytes, is returned in `pInfoSize`. Otherwise, `pInfoSize` must point to a variable set by the user to the size of the buffer, in bytes, pointed to by `pInfo`, and on return the variable is overwritten with the amount of data actually written to `pInfo`.

If `pInfoSize` is less than the maximum size that can be retrieved by the pipeline cache, then at most `pInfoSize` bytes will be written to `pInfo`, and `vkGetShaderInfoAMD` will return `VK_INCOMPLETE`.

Not all information is available for every shader and implementations may not support all kinds of information for any shader. When a certain type of information is unavailable, the function returns `VK_ERROR_FEATURE_NOT_PRESENT`.

If information is successfully and fully queried, the function will return `VK_SUCCESS`.

For `infoType` `VK_SHADER_INFO_TYPE_STATISTICS_AMD`, a `VkShaderStatisticsInfoAMD` structure will be written to the buffer pointed to by `pInfo`. This structure will be populated with statistics regarding the physical device resources used by that shader along with other miscellaneous information and is described in further detail below.

For `infoType` `VK_SHADER_INFO_TYPE_DISASSEMBLY_AMD`, `pInfo` is a pointer to a UTF-8 null-terminated string containing human-readable disassembly. The exact formatting and contents of the disassembly string are vendor-specific.

The formatting and contents of all other types of information, including `infoType` `VK_SHADER_INFO_TYPE_BINARY_AMD`, are left to the vendor and are not further specified by this extension.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pipeline` must be a valid VkPipeline handle

- `shaderStage` must be a valid VkShaderStageFlagBits value

- `infoType` must be a valid VkShaderInfoTypeAMD value

- `pInfoSize` must be a valid pointer to a `size_t` value

- If the value referenced by `pInfoSize` is not `0`, and `pInfo` is not `NULL`, `pInfo` must be a valid pointer to an array of `pInfoSize` bytes

- `pipeline` must have been created, allocated, or retrieved from `device`

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_FEATURE_NOT_PRESENT`

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

Possible values of vkGetShaderInfoAMD::`infoType`, specifying the information being queried from a shader, are:

    typedef enum VkShaderInfoTypeAMD {
        VK_SHADER_INFO_TYPE_STATISTICS_AMD = 0,
        VK_SHADER_INFO_TYPE_BINARY_AMD = 1,
        VK_SHADER_INFO_TYPE_DISASSEMBLY_AMD = 2,
        VK_SHADER_INFO_TYPE_MAX_ENUM_AMD = 0x7FFFFFFF
    } VkShaderInfoTypeAMD;

- `VK_SHADER_INFO_TYPE_STATISTICS_AMD` specifies that device resources used by a shader will be queried.

- `VK_SHADER_INFO_TYPE_BINARY_AMD` specifies that implementation-specific information will be queried.

- `VK_SHADER_INFO_TYPE_DISASSEMBLY_AMD` specifies that human-readable dissassembly of a shader.

The `VkShaderStatisticsInfoAMD` structure is defined as:

    typedef struct VkShaderStatisticsInfoAMD {
        VkShaderStageFlags          shaderStageMask;
        VkShaderResourceUsageAMD    resourceUsage;
        uint32_t                    numPhysicalVgprs;
        uint32_t                    numPhysicalSgprs;
        uint32_t                    numAvailableVgprs;
        uint32_t                    numAvailableSgprs;
        uint32_t                    computeWorkGroupSize[3];
    } VkShaderStatisticsInfoAMD;

- `shaderStageMask` are the combination of logical shader stages contained within this shader.

- `resourceUsage` is a VkShaderResourceUsageAMD structure describing internal physical device resources used by this shader.

- `numPhysicalVgprs` is the maximum number of vector instruction general-purpose registers (VGPRs) available to the physical device.

- `numPhysicalSgprs` is the maximum number of scalar instruction general-purpose registers (SGPRs) available to the physical device.

- `numAvailableVgprs` is the maximum limit of VGPRs made available to the shader compiler.

- `numAvailableSgprs` is the maximum limit of SGPRs made available to the shader compiler.

- `computeWorkGroupSize` is the local workgroup size of this shader in { X, Y, Z } dimensions.

Some implementations may merge multiple logical shader stages together in a single shader. In such cases, `shaderStageMask` will contain a bitmask of all of the stages that are active within that shader. Consequently, if specifying those stages as input to vkGetShaderInfoAMD, the same output information may be returned for all such shader stage queries.

The number of available VGPRs and SGPRs (`numAvailableVgprs` and `numAvailableSgprs` respectively) are the shader-addressable subset of physical registers that is given as a limit to the compiler for register assignment. These values may further be limited by implementations due to performance optimizations where register pressure is a bottleneck.

The `VkShaderResourceUsageAMD` structure is defined as:

    typedef struct VkShaderResourceUsageAMD {
        uint32_t    numUsedVgprs;
        uint32_t    numUsedSgprs;
        uint32_t    ldsSizePerLocalWorkGroup;
        size_t      ldsUsageSizeInBytes;
        size_t      scratchMemUsageInBytes;
    } VkShaderResourceUsageAMD;

- `numUsedVgprs` is the number of vector instruction general-purpose registers used by this shader.

- `numUsedSgprs` is the number of scalar instruction general-purpose registers used by this shader.

- `ldsSizePerLocalWorkGroup` is the maximum local data store size per work group in bytes.

- `ldsUsageSizeInBytes` is the LDS usage size in bytes per work group by this shader.

- `scratchMemUsageInBytes` is the scratch memory usage in bytes by this shader.

### 9.12. Pipeline Compiler Control

The compilation of a pipeline can be tuned by adding a `VkPipelineCompilerControlCreateInfoAMD` structure to the `pNext` chain of VkGraphicsPipelineCreateInfo or VkComputePipelineCreateInfo.

    typedef struct VkPipelineCompilerControlCreateInfoAMD {
        VkStructureType                      sType;
        const void*                          pNext;
        VkPipelineCompilerControlFlagsAMD    compilerControlFlags;
    } VkPipelineCompilerControlCreateInfoAMD;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `compilerControlFlags` is a bitmask of VkPipelineCompilerControlFlagBitsAMD affecting how the pipeline will be compiled.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_COMPILER_CONTROL_CREATE_INFO_AMD`

- `compilerControlFlags` must be `0`

There are currently no available flags for this extension; flags will be added by future versions of this extension.

    typedef enum VkPipelineCompilerControlFlagBitsAMD {
        VK_PIPELINE_COMPILER_CONTROL_FLAG_BITS_MAX_ENUM_AMD = 0x7FFFFFFF
    } VkPipelineCompilerControlFlagBitsAMD;

### 9.13. Ray Tracing Pipeline

Ray tracing pipelines consist of multiple shader stages, fixed-function traversal stages, and a pipeline layout.

To create ray tracing pipelines, call:

    VkResult vkCreateRayTracingPipelinesNV(
        VkDevice                                    device,
        VkPipelineCache                             pipelineCache,
        uint32_t                                    createInfoCount,
        const VkRayTracingPipelineCreateInfoNV*     pCreateInfos,
        const VkAllocationCallbacks*                pAllocator,
        VkPipeline*                                 pPipelines);

- `device` is the logical device that creates the ray tracing pipelines.

- `pipelineCache` is either VK_NULL_HANDLE, indicating that pipeline caching is disabled, or the handle of a valid pipeline cache object, in which case use of that cache is enabled for the duration of the command.

- `createInfoCount` is the length of the `pCreateInfos` and `pPipelines` arrays.

- `pCreateInfos` is a pointer to an array of VkRayTracingPipelineCreateInfoNV structures.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pPipelines` is a pointer to an array in which the resulting ray tracing pipeline objects are returned.

Valid Usage

- [[VUID-{refpage}-flags-03415]] If the `flags` member of any element of `pCreateInfos` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, and the `basePipelineIndex` member of that same element is not `-1`, `basePipelineIndex` must be less than the index into `pCreateInfos` that corresponds to that element

- [[VUID-{refpage}-flags-03416]] If the `flags` member of any element of `pCreateInfos` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, the base pipeline must have been created with the `VK_PIPELINE_CREATE_ALLOW_DERIVATIVES_BIT` flag set

- [[VUID-{refpage}-pipelineCache-02903]] If `pipelineCache` was created with `VK_PIPELINE_CACHE_CREATE_EXTERNALLY_SYNCHRONIZED_BIT_EXT`, host access to `pipelineCache` must be externally synchronized.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `pipelineCache` is not VK_NULL_HANDLE, `pipelineCache` must be a valid VkPipelineCache handle

- `pCreateInfos` must be a valid pointer to an array of `createInfoCount` valid VkRayTracingPipelineCreateInfoNV structures

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pPipelines` must be a valid pointer to an array of `createInfoCount` VkPipeline handles

- `createInfoCount` must be greater than `0`

- If `pipelineCache` is a valid handle, it must have been created, allocated, or retrieved from `device`

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_INVALID_SHADER_NV`

To create ray tracing pipelines, call:

    VkResult vkCreateRayTracingPipelinesKHR(
        VkDevice                                    device,
        VkPipelineCache                             pipelineCache,
        uint32_t                                    createInfoCount,
        const VkRayTracingPipelineCreateInfoKHR*    pCreateInfos,
        const VkAllocationCallbacks*                pAllocator,
        VkPipeline*                                 pPipelines);

- `device` is the logical device that creates the ray tracing pipelines.

- `pipelineCache` is either VK_NULL_HANDLE, indicating that pipeline caching is disabled, or the handle of a valid pipeline cache object, in which case use of that cache is enabled for the duration of the command.

- `createInfoCount` is the length of the `pCreateInfos` and `pPipelines` arrays.

- `pCreateInfos` is a pointer to an array of VkRayTracingPipelineCreateInfoKHR structures.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pPipelines` is a pointer to an array in which the resulting ray tracing pipeline objects are returned.

The `VK_ERROR_INVALID_OPAQUE_CAPTURE_ADDRESS` error is returned if the implementation is unable to re-use the shader group handles provided in VkRayTracingShaderGroupCreateInfoKHR→`pShaderGroupCaptureReplayHandle` when VkPhysicalDeviceRayTracingFeaturesKHR→`rayTracingShaderGroupHandleCaptureReplay` is enabled.

Valid Usage

- [[VUID-{refpage}-flags-03415]] If the `flags` member of any element of `pCreateInfos` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, and the `basePipelineIndex` member of that same element is not `-1`, `basePipelineIndex` must be less than the index into `pCreateInfos` that corresponds to that element

- [[VUID-{refpage}-flags-03416]] If the `flags` member of any element of `pCreateInfos` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, the base pipeline must have been created with the `VK_PIPELINE_CREATE_ALLOW_DERIVATIVES_BIT` flag set

- [[VUID-{refpage}-pipelineCache-02903]] If `pipelineCache` was created with `VK_PIPELINE_CACHE_CREATE_EXTERNALLY_SYNCHRONIZED_BIT_EXT`, host access to `pipelineCache` must be externally synchronized.

- The `rayTracing` feature must be enabled

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `pipelineCache` is not VK_NULL_HANDLE, `pipelineCache` must be a valid VkPipelineCache handle

- `pCreateInfos` must be a valid pointer to an array of `createInfoCount` valid VkRayTracingPipelineCreateInfoKHR structures

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pPipelines` must be a valid pointer to an array of `createInfoCount` VkPipeline handles

- `createInfoCount` must be greater than `0`

- If `pipelineCache` is a valid handle, it must have been created, allocated, or retrieved from `device`

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_OPERATION_DEFERRED_KHR`

  - `VK_OPERATION_NOT_DEFERRED_KHR`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_INVALID_OPAQUE_CAPTURE_ADDRESS`

The `VkRayTracingPipelineCreateInfoNV` structure is defined as:

    typedef struct VkRayTracingPipelineCreateInfoNV {
        VkStructureType                               sType;
        const void*                                   pNext;
        VkPipelineCreateFlags                         flags;
        uint32_t                                      stageCount;
        const VkPipelineShaderStageCreateInfo*        pStages;
        uint32_t                                      groupCount;
        const VkRayTracingShaderGroupCreateInfoNV*    pGroups;
        uint32_t                                      maxRecursionDepth;
        VkPipelineLayout                              layout;
        VkPipeline                                    basePipelineHandle;
        int32_t                                       basePipelineIndex;
    } VkRayTracingPipelineCreateInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkPipelineCreateFlagBits specifying how the pipeline will be generated.

- `stageCount` is the number of entries in the `pStages` array.

- `pStages` is an array of size `stageCount` structures of type VkPipelineShaderStageCreateInfo describing the set of the shader stages to be included in the ray tracing pipeline.

- `groupCount` is the number of entries in the `pGroups` array.

- `pGroups` is an array of size `groupCount` structures of type VkRayTracingShaderGroupCreateInfoNV describing the set of the shader stages to be included in each shader group in the ray tracing pipeline.

- `maxRecursionDepth` is the maximum recursion depth of shaders executed by this pipeline.

- `layout` is the description of binding locations used by both the pipeline and descriptor sets used with the pipeline.

- `basePipelineHandle` is a pipeline to derive from.

- `basePipelineIndex` is an index into the `pCreateInfos` parameter to use as a pipeline to derive from.

The parameters `basePipelineHandle` and `basePipelineIndex` are described in more detail in Pipeline Derivatives.

Valid Usage

- [[VUID-{refpage}-flags-03421]] If `flags` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, and `basePipelineIndex` is `-1`, `basePipelineHandle` must be a valid handle to a ray tracing `VkPipeline`

- [[VUID-{refpage}-flags-03422]] If `flags` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, and `basePipelineHandle` is VK_NULL_HANDLE, `basePipelineIndex` must be a valid index into the calling command’s `pCreateInfos` parameter

- [[VUID-{refpage}-flags-03423]] If `flags` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, and `basePipelineIndex` is not `-1`, `basePipelineHandle` must be VK_NULL_HANDLE

- [[VUID-{refpage}-flags-03424]] If `flags` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, and `basePipelineHandle` is not VK_NULL_HANDLE, `basePipelineIndex` must be `-1`

- [[VUID-{refpage}-stage-03425]] The `stage` member of at least one element of `pStages` must be `VK_SHADER_STAGE_RAYGEN_BIT_KHR`

- [[VUID-{refpage}-pStages-03426]] The shader code for the entry points identified by `pStages`, and the rest of the state identified by this structure must adhere to the pipeline linking rules described in the Shader Interfaces chapter

- [[VUID-{refpage}-layout-03427]] `layout` must be consistent with all shaders specified in `pStages`

- [[VUID-{refpage}-layout-03428]] The number of resources in `layout` accessible to each shader stage that is used by the pipeline must be less than or equal to VkPhysicalDeviceLimits::`maxPerStageResources`

- [[VUID-{refpage}-flags-02904]] `flags` must not include `VK_PIPELINE_CREATE_INDIRECT_BINDABLE_BIT_NV`

- [[VUID-{refpage}-pipelineCreationCacheControl-02905]] If the `pipelineCreationCacheControl` feature is not enabled, `flags` must not include `VK_PIPELINE_CREATE_FAIL_ON_PIPELINE_COMPILE_REQUIRED_BIT_EXT` or `VK_PIPELINE_CREATE_EARLY_RETURN_ON_FAILURE_BIT_EXT`

- `flags` must not include `VK_PIPELINE_CREATE_LIBRARY_BIT_KHR`

- `maxRecursionDepth` must be less than or equal to VkPhysicalDeviceRayTracingPropertiesNV::`maxRecursionDepth`

- `flags` must not include `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_ANY_HIT_SHADERS_BIT_KHR`

- `flags` must not include `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_CLOSEST_HIT_SHADERS_BIT_KHR`

- `flags` must not include `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_MISS_SHADERS_BIT_KHR`

- `flags` must not include `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_INTERSECTION_SHADERS_BIT_KHR`

- `flags` must not include `VK_PIPELINE_CREATE_RAY_TRACING_SKIP_AABBS_BIT_KHR`

- `flags` must not include `VK_PIPELINE_CREATE_RAY_TRACING_SKIP_TRIANGLES_BIT_KHR`

- `flags` must not include both `VK_PIPELINE_CREATE_DEFER_COMPILE_BIT_NV` and `VK_PIPELINE_CREATE_FAIL_ON_PIPELINE_COMPILE_REQUIRED_BIT_EXT` at the same time.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_RAY_TRACING_PIPELINE_CREATE_INFO_NV`

- `pNext` must be `NULL` or a pointer to a valid instance of VkPipelineCreationFeedbackCreateInfoEXT

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be a valid combination of VkPipelineCreateFlagBits values

- `pStages` must be a valid pointer to an array of `stageCount` valid VkPipelineShaderStageCreateInfo structures

- `pGroups` must be a valid pointer to an array of `groupCount` valid VkRayTracingShaderGroupCreateInfoNV structures

- `layout` must be a valid VkPipelineLayout handle

- `stageCount` must be greater than `0`

- `groupCount` must be greater than `0`

- Both of `basePipelineHandle`, and `layout` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

The `VkRayTracingPipelineCreateInfoKHR` structure is defined as:

    typedef struct VkRayTracingPipelineCreateInfoKHR {
        VkStructureType                                      sType;
        const void*                                          pNext;
        VkPipelineCreateFlags                                flags;
        uint32_t                                             stageCount;
        const VkPipelineShaderStageCreateInfo*               pStages;
        uint32_t                                             groupCount;
        const VkRayTracingShaderGroupCreateInfoKHR*          pGroups;
        uint32_t                                             maxRecursionDepth;
        VkPipelineLibraryCreateInfoKHR                       libraries;
        const VkRayTracingPipelineInterfaceCreateInfoKHR*    pLibraryInterface;
        VkPipelineLayout                                     layout;
        VkPipeline                                           basePipelineHandle;
        int32_t                                              basePipelineIndex;
    } VkRayTracingPipelineCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkPipelineCreateFlagBits specifying how the pipeline will be generated.

- `stageCount` is the number of entries in the `pStages` array.

- `pStages` is a pointer to an array of `stageCount` VkPipelineShaderStageCreateInfo structures describing the set of the shader stages to be included in the ray tracing pipeline.

- `groupCount` is the number of entries in the `pGroups` array.

- `pGroups` is a pointer to an array of `groupCount` VkRayTracingShaderGroupCreateInfoKHR structures describing the set of the shader stages to be included in each shader group in the ray tracing pipeline.

- `maxRecursionDepth` is the maximum recursion depth of shaders executed by this pipeline.

- `libraries` is a VkPipelineLibraryCreateInfoKHR structure defining pipeline libraries to include.

- `pLibraryInterface` is a pointer to a VkRayTracingPipelineInterfaceCreateInfoKHR structure defining additional information when using pipeline libraries.

- `layout` is the description of binding locations used by both the pipeline and descriptor sets used with the pipeline.

- `basePipelineHandle` is a pipeline to derive from.

- `basePipelineIndex` is an index into the `pCreateInfos` parameter to use as a pipeline to derive from.

The parameters `basePipelineHandle` and `basePipelineIndex` are described in more detail in Pipeline Derivatives.

When `VK_PIPELINE_CREATE_LIBRARY_BIT_KHR` is specified, this pipeline defines a pipeline library which cannot be bound as a ray tracing pipeline directly. Instead, pipeline libraries define common shaders and shader groups which can be included in future pipeline creation.

If pipeline libraries are included in `libraries`, shaders defined in those libraries are treated as if they were defined as additional entries in `pStages`, appended in the order they appear in the `pLibraries` array and in the `pStages` array when those libraries were defined.

When referencing shader groups in order to obtain a shader group handle, groups defined in those libraries are treated as if they were defined as additional entries in `pGroups`, appended in the order they appear in the `pLibraries` array and in the `pGroups` array when those libraries were defined. The shaders these groups reference are set when the pipeline library is created, referencing those specified in the pipeline library, not in the pipeline that includes it.

If the VkDeferredOperationInfoKHR structure is included in the `pNext` chain of VkRayTracingPipelineCreateInfoKHR, the operation of this pipeline creation is deferred, as defined in the Deferred Host Operations chapter.

Valid Usage

- [[VUID-{refpage}-flags-03421]] If `flags` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, and `basePipelineIndex` is `-1`, `basePipelineHandle` must be a valid handle to a ray tracing `VkPipeline`

- [[VUID-{refpage}-flags-03422]] If `flags` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, and `basePipelineHandle` is VK_NULL_HANDLE, `basePipelineIndex` must be a valid index into the calling command’s `pCreateInfos` parameter

- [[VUID-{refpage}-flags-03423]] If `flags` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, and `basePipelineIndex` is not `-1`, `basePipelineHandle` must be VK_NULL_HANDLE

- [[VUID-{refpage}-flags-03424]] If `flags` contains the `VK_PIPELINE_CREATE_DERIVATIVE_BIT` flag, and `basePipelineHandle` is not VK_NULL_HANDLE, `basePipelineIndex` must be `-1`

- [[VUID-{refpage}-stage-03425]] The `stage` member of at least one element of `pStages` must be `VK_SHADER_STAGE_RAYGEN_BIT_KHR`

- [[VUID-{refpage}-pStages-03426]] The shader code for the entry points identified by `pStages`, and the rest of the state identified by this structure must adhere to the pipeline linking rules described in the Shader Interfaces chapter

- [[VUID-{refpage}-layout-03427]] `layout` must be consistent with all shaders specified in `pStages`

- [[VUID-{refpage}-layout-03428]] The number of resources in `layout` accessible to each shader stage that is used by the pipeline must be less than or equal to VkPhysicalDeviceLimits::`maxPerStageResources`

- [[VUID-{refpage}-flags-02904]] `flags` must not include `VK_PIPELINE_CREATE_INDIRECT_BINDABLE_BIT_NV`

- [[VUID-{refpage}-pipelineCreationCacheControl-02905]] If the `pipelineCreationCacheControl` feature is not enabled, `flags` must not include `VK_PIPELINE_CREATE_FAIL_ON_PIPELINE_COMPILE_REQUIRED_BIT_EXT` or `VK_PIPELINE_CREATE_EARLY_RETURN_ON_FAILURE_BIT_EXT`

- `maxRecursionDepth` must be less than or equal to VkPhysicalDeviceRayTracingPropertiesKHR::`maxRecursionDepth`

- If `flags` includes `VK_PIPELINE_CREATE_LIBRARY_BIT_KHR`, `pLibraryInterface` must not be `NULL`

- If the `libraryCount` member of `libraries` is greater than `0`, `pLibraryInterface` must not be `NULL`

- Each element of the `pLibraries` member of `libraries` must have been created with the value of `maxRecursionDepth` equal to that in this pipeline

- Each element of the `pLibraries` member of `libraries` must have been created with a `layout` that is compatible with the `layout` in this pipeline

- Each element of the `pLibraries` member of `libraries` must have been created with values of the `maxPayloadSize`, `maxAttributeSize`, and `maxCallableSize` members of `pLibraryInterface` equal to those in this pipeline

- If `flags` includes `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_ANY_HIT_SHADERS_BIT_KHR`, for any element of `pGroups` with a `type` of `VK_RAY_TRACING_SHADER_GROUP_TYPE_TRIANGLES_HIT_GROUP_KHR` or `VK_RAY_TRACING_SHADER_GROUP_TYPE_PROCEDURAL_HIT_GROUP_KHR`, the `anyHitShader` of that element must not be `VK_SHADER_UNUSED_KHR`

- If `flags` includes `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_CLOSEST_HIT_SHADERS_BIT_KHR`, for any element of `pGroups` with a `type` of `VK_RAY_TRACING_SHADER_GROUP_TYPE_TRIANGLES_HIT_GROUP_KHR` or `VK_RAY_TRACING_SHADER_GROUP_TYPE_PROCEDURAL_HIT_GROUP_KHR`, the `closestHitShader` of that element must not be `VK_SHADER_UNUSED_KHR`

- If the `rayTracingPrimitiveCulling` feature is not enabled, `flags` must not include `VK_PIPELINE_CREATE_RAY_TRACING_SKIP_AABBS_BIT_KHR`

- If the `rayTracingPrimitiveCulling` feature is not enabled, `flags` must not include `VK_PIPELINE_CREATE_RAY_TRACING_SKIP_TRIANGLES_BIT_KHR`

- If `libraries.pname`:libraryCount is zero, then `stageCount` must not be zero

- If `libraries.pname`:libraryCount is zero, then `groupCount` must not be zero

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_RAY_TRACING_PIPELINE_CREATE_INFO_KHR`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkDeferredOperationInfoKHR or VkPipelineCreationFeedbackCreateInfoEXT

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be a valid combination of VkPipelineCreateFlagBits values

- If `stageCount` is not `0`, `pStages` must be a valid pointer to an array of `stageCount` valid VkPipelineShaderStageCreateInfo structures

- If `groupCount` is not `0`, `pGroups` must be a valid pointer to an array of `groupCount` valid VkRayTracingShaderGroupCreateInfoKHR structures

- `libraries` must be a valid VkPipelineLibraryCreateInfoKHR structure

- If `pLibraryInterface` is not `NULL`, `pLibraryInterface` must be a valid pointer to a valid VkRayTracingPipelineInterfaceCreateInfoKHR structure

- `layout` must be a valid VkPipelineLayout handle

- Both of `basePipelineHandle`, and `layout` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

The `VkRayTracingShaderGroupCreateInfoNV` structure is defined as:

    typedef struct VkRayTracingShaderGroupCreateInfoNV {
        VkStructureType                   sType;
        const void*                       pNext;
        VkRayTracingShaderGroupTypeKHR    type;
        uint32_t                          generalShader;
        uint32_t                          closestHitShader;
        uint32_t                          anyHitShader;
        uint32_t                          intersectionShader;
    } VkRayTracingShaderGroupCreateInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `type` is the type of hit group specified in this structure.

- `generalShader` is the index of the ray generation, miss, or callable shader from VkRayTracingPipelineCreateInfoNV::`pStages` in the group if the shader group has `type` of `VK_RAY_TRACING_SHADER_GROUP_TYPE_GENERAL_NV`, and `VK_SHADER_UNUSED_NV` otherwise.

- `closestHitShader` is the optional index of the closest hit shader from VkRayTracingPipelineCreateInfoNV::`pStages` in the group if the shader group has `type` of `VK_RAY_TRACING_SHADER_GROUP_TYPE_TRIANGLES_HIT_GROUP_NV` or `VK_RAY_TRACING_SHADER_GROUP_TYPE_PROCEDURAL_HIT_GROUP_NV`, and `VK_SHADER_UNUSED_NV` otherwise.

- `anyHitShader` is the optional index of the any-hit shader from VkRayTracingPipelineCreateInfoNV::`pStages` in the group if the shader group has `type` of `VK_RAY_TRACING_SHADER_GROUP_TYPE_TRIANGLES_HIT_GROUP_NV` or `VK_RAY_TRACING_SHADER_GROUP_TYPE_PROCEDURAL_HIT_GROUP_NV`, and `VK_SHADER_UNUSED_NV` otherwise.

- `intersectionShader` is the index of the intersection shader from VkRayTracingPipelineCreateInfoNV::`pStages` in the group if the shader group has `type` of `VK_RAY_TRACING_SHADER_GROUP_TYPE_PROCEDURAL_HIT_GROUP_NV`, and `VK_SHADER_UNUSED_NV` otherwise.

Valid Usage

- If `type` is `VK_RAY_TRACING_SHADER_GROUP_TYPE_GENERAL_NV` then `generalShader` must be a valid index into VkRayTracingPipelineCreateInfoNV::`pStages` referring to a shader of `VK_SHADER_STAGE_RAYGEN_BIT_NV`, `VK_SHADER_STAGE_MISS_BIT_NV`, or `VK_SHADER_STAGE_CALLABLE_BIT_NV`

- If `type` is `VK_RAY_TRACING_SHADER_GROUP_TYPE_GENERAL_NV` then `closestHitShader`, `anyHitShader`, and `intersectionShader` must be `VK_SHADER_UNUSED_NV`

- If `type` is `VK_RAY_TRACING_SHADER_GROUP_TYPE_PROCEDURAL_HIT_GROUP_NV` then `intersectionShader` must be a valid index into VkRayTracingPipelineCreateInfoNV::`pStages` referring to a shader of `VK_SHADER_STAGE_INTERSECTION_BIT_NV`

- If `type` is `VK_RAY_TRACING_SHADER_GROUP_TYPE_TRIANGLES_HIT_GROUP_NV` then `intersectionShader` must be `VK_SHADER_UNUSED_NV`

- `closestHitShader` must be either `VK_SHADER_UNUSED_NV` or a valid index into VkRayTracingPipelineCreateInfoNV::`pStages` referring to a shader of `VK_SHADER_STAGE_CLOSEST_HIT_BIT_NV`

- `anyHitShader` must be either `VK_SHADER_UNUSED_NV` or a valid index into VkRayTracingPipelineCreateInfoNV::`pStages` referring to a shader of `VK_SHADER_STAGE_ANY_HIT_BIT_NV`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_RAY_TRACING_SHADER_GROUP_CREATE_INFO_NV`

- `pNext` must be `NULL`

- `type` must be a valid VkRayTracingShaderGroupTypeKHR value

The `VkRayTracingShaderGroupCreateInfoKHR` structure is defined as:

    typedef struct VkRayTracingShaderGroupCreateInfoKHR {
        VkStructureType                   sType;
        const void*                       pNext;
        VkRayTracingShaderGroupTypeKHR    type;
        uint32_t                          generalShader;
        uint32_t                          closestHitShader;
        uint32_t                          anyHitShader;
        uint32_t                          intersectionShader;
        const void*                       pShaderGroupCaptureReplayHandle;
    } VkRayTracingShaderGroupCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `type` is the type of hit group specified in this structure.

- `generalShader` is the index of the ray generation, miss, or callable shader from VkRayTracingPipelineCreateInfoKHR::`pStages` in the group if the shader group has `type` of `VK_RAY_TRACING_SHADER_GROUP_TYPE_GENERAL_KHR`, and `VK_SHADER_UNUSED_KHR` otherwise.

- `closestHitShader` is the optional index of the closest hit shader from VkRayTracingPipelineCreateInfoKHR::`pStages` in the group if the shader group has `type` of `VK_RAY_TRACING_SHADER_GROUP_TYPE_TRIANGLES_HIT_GROUP_KHR` or `VK_RAY_TRACING_SHADER_GROUP_TYPE_PROCEDURAL_HIT_GROUP_KHR`, and `VK_SHADER_UNUSED_KHR` otherwise.

- `anyHitShader` is the optional index of the any-hit shader from VkRayTracingPipelineCreateInfoKHR::`pStages` in the group if the shader group has `type` of `VK_RAY_TRACING_SHADER_GROUP_TYPE_TRIANGLES_HIT_GROUP_KHR` or `VK_RAY_TRACING_SHADER_GROUP_TYPE_PROCEDURAL_HIT_GROUP_KHR`, and `VK_SHADER_UNUSED_KHR` otherwise.

- `intersectionShader` is the index of the intersection shader from VkRayTracingPipelineCreateInfoKHR::`pStages` in the group if the shader group has `type` of `VK_RAY_TRACING_SHADER_GROUP_TYPE_PROCEDURAL_HIT_GROUP_KHR`, and `VK_SHADER_UNUSED_KHR` otherwise.

- `pShaderGroupCaptureReplayHandle` is an optional pointer to replay information for this shader group. Ignored if VkPhysicalDeviceRayTracingFeaturesKHR::`rayTracingShaderGroupHandleCaptureReplay` is `VK_FALSE`.

Valid Usage

- If `type` is `VK_RAY_TRACING_SHADER_GROUP_TYPE_GENERAL_KHR` then `generalShader` must be a valid index into VkRayTracingPipelineCreateInfoKHR::`pStages` referring to a shader of `VK_SHADER_STAGE_RAYGEN_BIT_KHR`, `VK_SHADER_STAGE_MISS_BIT_KHR`, or `VK_SHADER_STAGE_CALLABLE_BIT_KHR`

- If `type` is `VK_RAY_TRACING_SHADER_GROUP_TYPE_GENERAL_KHR` then `closestHitShader`, `anyHitShader`, and `intersectionShader` must be `VK_SHADER_UNUSED_KHR`

- If `type` is `VK_RAY_TRACING_SHADER_GROUP_TYPE_PROCEDURAL_HIT_GROUP_KHR` then `intersectionShader` must be a valid index into VkRayTracingPipelineCreateInfoKHR::`pStages` referring to a shader of `VK_SHADER_STAGE_INTERSECTION_BIT_KHR`

- If `type` is `VK_RAY_TRACING_SHADER_GROUP_TYPE_TRIANGLES_HIT_GROUP_KHR` then `intersectionShader` must be `VK_SHADER_UNUSED_KHR`

- `closestHitShader` must be either `VK_SHADER_UNUSED_KHR` or a valid index into VkRayTracingPipelineCreateInfoKHR::`pStages` referring to a shader of `VK_SHADER_STAGE_CLOSEST_HIT_BIT_KHR`

- `anyHitShader` must be either `VK_SHADER_UNUSED_KHR` or a valid index into VkRayTracingPipelineCreateInfoKHR::`pStages` referring to a shader of `VK_SHADER_STAGE_ANY_HIT_BIT_KHR`

- If VkPhysicalDeviceRayTracingFeaturesKHR::`rayTracingShaderGroupHandleCaptureReplayMixed` is `VK_FALSE` then `pShaderGroupCaptureReplayHandle` must not be provided if it has not been provided on a previous call to ray tracing pipeline creation

- If VkPhysicalDeviceRayTracingFeaturesKHR::`rayTracingShaderGroupHandleCaptureReplayMixed` is `VK_FALSE` then the caller must guarantee that no ray tracing pipeline creation commands with `pShaderGroupCaptureReplayHandle` provided execute simultaneously with ray tracing pipeline creation commands without `pShaderGroupCaptureReplayHandle` provided

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_RAY_TRACING_SHADER_GROUP_CREATE_INFO_KHR`

- `pNext` must be `NULL`

- `type` must be a valid VkRayTracingShaderGroupTypeKHR value

Possible values of `type` in `VkRayTracingShaderGroupCreateInfoKHR` are:

    typedef enum VkRayTracingShaderGroupTypeKHR {
        VK_RAY_TRACING_SHADER_GROUP_TYPE_GENERAL_KHR = 0,
        VK_RAY_TRACING_SHADER_GROUP_TYPE_TRIANGLES_HIT_GROUP_KHR = 1,
        VK_RAY_TRACING_SHADER_GROUP_TYPE_PROCEDURAL_HIT_GROUP_KHR = 2,
        VK_RAY_TRACING_SHADER_GROUP_TYPE_GENERAL_NV = VK_RAY_TRACING_SHADER_GROUP_TYPE_GENERAL_KHR,
        VK_RAY_TRACING_SHADER_GROUP_TYPE_TRIANGLES_HIT_GROUP_NV = VK_RAY_TRACING_SHADER_GROUP_TYPE_TRIANGLES_HIT_GROUP_KHR,
        VK_RAY_TRACING_SHADER_GROUP_TYPE_PROCEDURAL_HIT_GROUP_NV = VK_RAY_TRACING_SHADER_GROUP_TYPE_PROCEDURAL_HIT_GROUP_KHR,
        VK_RAY_TRACING_SHADER_GROUP_TYPE_MAX_ENUM_KHR = 0x7FFFFFFF
    } VkRayTracingShaderGroupTypeKHR;

or the equivalent

    typedef VkRayTracingShaderGroupTypeKHR VkRayTracingShaderGroupTypeNV;

- `VK_RAY_TRACING_SHADER_GROUP_TYPE_GENERAL_KHR` indicates a shader group with a single `VK_SHADER_STAGE_RAYGEN_BIT_KHR`, `VK_SHADER_STAGE_MISS_BIT_KHR`, or `VK_SHADER_STAGE_CALLABLE_BIT_KHR` shader in it.

- `VK_RAY_TRACING_SHADER_GROUP_TYPE_TRIANGLES_HIT_GROUP_KHR` specifies a shader group that only hits triangles and must not contain an intersection shader, only closest hit and any-hit shaders.

- `VK_RAY_TRACING_SHADER_GROUP_TYPE_PROCEDURAL_HIT_GROUP_KHR` specifies a shader group that only intersects with custom geometry and must contain an intersection shader and may contain closest hit and any-hit shaders.

| Note For current group types, the hit group type could be inferred from the presence or absence of the intersection shader, but we provide the type explicitly for future hit groups that do not have that property.

The `VkRayTracingPipelineInterfaceCreateInfoKHR` structure is defined as:

    typedef struct VkRayTracingPipelineInterfaceCreateInfoKHR {
        VkStructureType    sType;
        const void*        pNext;
        uint32_t           maxPayloadSize;
        uint32_t           maxAttributeSize;
        uint32_t           maxCallableSize;
    } VkRayTracingPipelineInterfaceCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `maxPayloadSize` is the maximum payload size in bytes used by any shader in the pipeline.

- `maxAttributeSize` is the maximum attribute structure size in bytes used by any shader in the pipeline.

- `maxCallableSize` is the maximum callable data size in bytes used by any shader in the pipeline.

`maxPayloadSize` is calculated as the maximum number of bytes used by any block declared in the `RayPayloadKHR` or `IncomingRayPayloadKHR` storage classes. `maxAttributeSize` is calculated as the maximum number of bytes used by any block declared in the `HitAttributeKHR` storage class. `maxCallableSize` is calculated as the maximum number of bytes used by any block declred in the `CallableDataKHR` or `IncomingCallableDataKHR`. As variables in these storage classes do not have explicit offsets, the size should be calculated as if each variable has a scalar alignment equal to the largest scalar alignment of any of the block’s members.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_RAY_TRACING_PIPELINE_INTERFACE_CREATE_INFO_KHR`

- `pNext` must be `NULL`

To query the opaque handles of shaders in the ray tracing pipeline, call:

    VkResult vkGetRayTracingShaderGroupHandlesKHR(
        VkDevice                                    device,
        VkPipeline                                  pipeline,
        uint32_t                                    firstGroup,
        uint32_t                                    groupCount,
        size_t                                      dataSize,
        void*                                       pData);

or the equivalent command

    VkResult vkGetRayTracingShaderGroupHandlesNV(
        VkDevice                                    device,
        VkPipeline                                  pipeline,
        uint32_t                                    firstGroup,
        uint32_t                                    groupCount,
        size_t                                      dataSize,
        void*                                       pData);

- `device` is the logical device containing the ray tracing pipeline.

- `pipeline` is the ray tracing pipeline object containing the shaders.

- `firstGroup` is the index of the first group to retrieve a handle for from the VkRayTracingPipelineCreateInfoKHR::`pGroups` or VkRayTracingPipelineCreateInfoNV::`pGroups` array.

- `groupCount` is the number of shader handles to retrieve.

- `dataSize` is the size in bytes of the buffer pointed to by `pData`.

- `pData` is a pointer to a user-allocated buffer where the results will be written.

Valid Usage

- The sum of `firstGroup` and `groupCount` must be less than the number of shader groups in `pipeline`.

- `dataSize` must be at least VkPhysicalDeviceRayTracingPropertiesKHR::`shaderGroupHandleSize` × `groupCount`

- `pipeline` must have not been created with `VK_PIPELINE_CREATE_LIBRARY_BIT_KHR`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pipeline` must be a valid VkPipeline handle

- `pData` must be a valid pointer to an array of `dataSize` bytes

- `dataSize` must be greater than `0`

- `pipeline` must have been created, allocated, or retrieved from `device`

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

To query the optional capture handle information of shaders in the ray tracing pipeline, call:

    VkResult vkGetRayTracingCaptureReplayShaderGroupHandlesKHR(
        VkDevice                                    device,
        VkPipeline                                  pipeline,
        uint32_t                                    firstGroup,
        uint32_t                                    groupCount,
        size_t                                      dataSize,
        void*                                       pData);

- `device` is the logical device containing the ray tracing pipeline.

- `pipeline` is the ray tracing pipeline object containing the shaders.

- `firstGroup` is the index of the first group to retrieve a handle for from the VkRayTracingPipelineCreateInfoKHR::`pGroups` array.

- `groupCount` is the number of shader handles to retrieve.

- `dataSize` is the size in bytes of the buffer pointed to by `pData`.

- `pData` is a pointer to a user-allocated buffer where the results will be written.

Valid Usage

- The sum of `firstGroup` and `groupCount` must be less than the number of shader groups in `pipeline`.

- `dataSize` must be at least VkPhysicalDeviceRayTracingPropertiesKHR::`shaderGroupHandleCaptureReplaySize` × `groupCount`

- `VkPhysicalDeviceRayTracingFeaturesKHR`::`rayTracingShaderGroupHandleCaptureReplay` must be enabled to call this function.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pipeline` must be a valid VkPipeline handle

- `pData` must be a valid pointer to an array of `dataSize` bytes

- `dataSize` must be greater than `0`

- `pipeline` must have been created, allocated, or retrieved from `device`

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

Ray tracing pipelines can contain more shaders than a graphics or compute pipeline, so to allow parallel compilation of shaders within a pipeline, an application can choose to defer compilation until a later point in time.

To compile a deferred shader in a pipeline call:

    VkResult vkCompileDeferredNV(
        VkDevice                                    device,
        VkPipeline                                  pipeline,
        uint32_t                                    shader);

- `device` is the logical device containing the ray tracing pipeline.

- `pipeline` is the ray tracing pipeline object containing the shaders.

- `shader` is the index of the shader to compile.

Valid Usage

- `pipeline` must have been created with `VK_PIPELINE_CREATE_DEFER_COMPILE_BIT_NV`

- `shader` must not have been called as a deferred compile before

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pipeline` must be a valid VkPipeline handle

- `pipeline` must have been created, allocated, or retrieved from `device`

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

### 9.14. Pipeline Creation Feedback

Feedback about the creation of a particular pipeline object can be obtained by adding a `VkPipelineCreationFeedbackCreateInfoEXT` structure to the `pNext` chain of VkGraphicsPipelineCreateInfo, VkRayTracingPipelineCreateInfoKHR, or VkComputePipelineCreateInfo. The `VkPipelineCreationFeedbackCreateInfoEXT` structure is defined as:

    typedef struct VkPipelineCreationFeedbackCreateInfoEXT {
        VkStructureType                   sType;
        const void*                       pNext;
        VkPipelineCreationFeedbackEXT*    pPipelineCreationFeedback;
        uint32_t                          pipelineStageCreationFeedbackCount;
        VkPipelineCreationFeedbackEXT*    pPipelineStageCreationFeedbacks;
    } VkPipelineCreationFeedbackCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `pPipelineCreationFeedback` is a pointer to a VkPipelineCreationFeedbackEXT structure.

- `pipelineStageCreationFeedbackCount` is the number of elements in `pPipelineStageCreationFeedbacks`.

- `pPipelineStageCreationFeedbacks` is a pointer to an array of `pipelineStageCreationFeedbackCount` VkPipelineCreationFeedbackEXT structures.

An implementation should write pipeline creation feedback to `pPipelineCreationFeedback` and may write pipeline stage creation feedback to `pPipelineStageCreationFeedbacks`. An implementation must set or clear the `VK_PIPELINE_CREATION_FEEDBACK_VALID_BIT_EXT` in VkPipelineCreationFeedbackEXT::`flags` for `pPipelineCreationFeedback` and every element of `pPipelineStageCreationFeedbacks`.

| Note One common scenario for an implementation to skip per-stage feedback is when `VK_PIPELINE_CREATION_FEEDBACK_APPLICATION_PIPELINE_CACHE_HIT_BIT_EXT` is set in `pPipelineCreationFeedback`.

When chained to VkRayTracingPipelineCreateInfoKHR or VkGraphicsPipelineCreateInfo, the `i` element of `pPipelineStageCreationFeedbacks` corresponds to the `i` element of VkRayTracingPipelineCreateInfoKHR::`pStages` or VkGraphicsPipelineCreateInfo::`pStages`. When chained to VkComputePipelineCreateInfo, the first element of `pPipelineStageCreationFeedbacks` corresponds to VkComputePipelineCreateInfo::`stage`.

Valid Usage

- When chained to VkGraphicsPipelineCreateInfo, VkPipelineCreationFeedbackEXT::`pipelineStageCreationFeedbackCount` must equal VkGraphicsPipelineCreateInfo::`stageCount`

- When chained to VkComputePipelineCreateInfo, VkPipelineCreationFeedbackEXT::`pipelineStageCreationFeedbackCount` must equal 1

- When chained to VkRayTracingPipelineCreateInfoKHR, VkPipelineCreationFeedbackEXT::`pipelineStageCreationFeedbackCount` must equal VkRayTracingPipelineCreateInfoKHR::`stageCount`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_CREATION_FEEDBACK_CREATE_INFO_EXT`

- `pPipelineCreationFeedback` must be a valid pointer to a VkPipelineCreationFeedbackEXT structure

- `pPipelineStageCreationFeedbacks` must be a valid pointer to an array of `pipelineStageCreationFeedbackCount` VkPipelineCreationFeedbackEXT structures

- `pipelineStageCreationFeedbackCount` must be greater than `0`

The `VkPipelineCreationFeedbackEXT` structure is defined as:

    typedef struct VkPipelineCreationFeedbackEXT {
        VkPipelineCreationFeedbackFlagsEXT    flags;
        uint64_t                              duration;
    } VkPipelineCreationFeedbackEXT;

- `flags` is a bitmask of VkPipelineCreationFeedbackFlagBitsEXT providing feedback about the creation of a pipeline or of a pipeline stage.

- `duration` is the duration spent creating a pipeline or pipeline stage in nanoseconds.

If the `VK_PIPELINE_CREATION_FEEDBACK_VALID_BIT_EXT` is not set in `flags`, an implementation must not set any other bits in `flags`, and all other `VkPipelineCreationFeedbackEXT` data members are undefined.

Possible values of the `flags` member of VkPipelineCreationFeedbackEXT are:

    typedef enum VkPipelineCreationFeedbackFlagBitsEXT {
        VK_PIPELINE_CREATION_FEEDBACK_VALID_BIT_EXT = 0x00000001,
        VK_PIPELINE_CREATION_FEEDBACK_APPLICATION_PIPELINE_CACHE_HIT_BIT_EXT = 0x00000002,
        VK_PIPELINE_CREATION_FEEDBACK_BASE_PIPELINE_ACCELERATION_BIT_EXT = 0x00000004,
        VK_PIPELINE_CREATION_FEEDBACK_FLAG_BITS_MAX_ENUM_EXT = 0x7FFFFFFF
    } VkPipelineCreationFeedbackFlagBitsEXT;

- `VK_PIPELINE_CREATION_FEEDBACK_VALID_BIT_EXT` indicates that the feedback information is valid.

- `VK_PIPELINE_CREATION_FEEDBACK_APPLICATION_PIPELINE_CACHE_HIT_BIT_EXT` indicates that a readily usable pipeline or pipeline stage was found in the `pipelineCache` specified by the application in the pipeline creation command.

  An implementation should set the `VK_PIPELINE_CREATION_FEEDBACK_APPLICATION_PIPELINE_CACHE_HIT_BIT_EXT` bit if it was able to avoid the large majority of pipeline or pipeline stage creation work by using the `pipelineCache` parameter of vkCreateGraphicsPipelines, vkCreateRayTracingPipelinesKHR, or vkCreateComputePipelines. When an implementation sets this bit for the entire pipeline, it may leave it unset for any stage.

  | Note Implementations are encouraged to provide a meaningful signal to applications using this bit. The intention is to communicate to the application that the pipeline or pipeline stage was created "as fast as it gets" using the pipeline cache provided by the application. If an implementation uses an internal cache, it is discouraged from setting this bit as the feedback would be unactionable.

- `VK_PIPELINE_CREATION_FEEDBACK_BASE_PIPELINE_ACCELERATION_BIT_EXT` indicates that the base pipeline specified by the `basePipelineHandle` or `basePipelineIndex` member of the `Vk*PipelineCreateInfo` structure was used to accelerate the creation of the pipeline.

  An implementation should set the `VK_PIPELINE_CREATION_FEEDBACK_BASE_PIPELINE_ACCELERATION_BIT_EXT` bit if it was able to avoid a significant amount of work by using the base pipeline.

  | Note While "significant amount of work" is subjective, implementations are encouraged to provide a meaningful signal to applications using this bit. For example, a 1% reduction in duration may not warrant setting this bit, while a 50% reduction would.

    typedef VkFlags VkPipelineCreationFeedbackFlagsEXT;

`VkPipelineCreationFeedbackFlagsEXT` is a bitmask type for providing zero or more VkPipelineCreationFeedbackFlagBitsEXT.

## 10. Memory Allocation

Vulkan memory is broken up into two categories, host memory and device memory.

### 10.1. Host Memory

Host memory is memory needed by the Vulkan implementation for non-device-visible storage.

| Note This memory may be used to store the implementation’s representation and state of Vulkan objects.

Vulkan provides applications the opportunity to perform host memory allocations on behalf of the Vulkan implementation. If this feature is not used, the implementation will perform its own memory allocations. Since most memory allocations are off the critical path, this is not meant as a performance feature. Rather, this can be useful for certain embedded systems, for debugging purposes (e.g. putting a guard page after all host allocations), or for memory allocation logging.

Allocators are provided by the application as a pointer to a `VkAllocationCallbacks` structure:

    typedef struct VkAllocationCallbacks {
        void*                                   pUserData;
        PFN_vkAllocationFunction                pfnAllocation;
        PFN_vkReallocationFunction              pfnReallocation;
        PFN_vkFreeFunction                      pfnFree;
        PFN_vkInternalAllocationNotification    pfnInternalAllocation;
        PFN_vkInternalFreeNotification          pfnInternalFree;
    } VkAllocationCallbacks;

- `pUserData` is a value to be interpreted by the implementation of the callbacks. When any of the callbacks in `VkAllocationCallbacks` are called, the Vulkan implementation will pass this value as the first parameter to the callback. This value can vary each time an allocator is passed into a command, even when the same object takes an allocator in multiple commands.

- `pfnAllocation` is a PFN_vkAllocationFunction pointer to an application-defined memory allocation function.

- `pfnReallocation` is a PFN_vkReallocationFunction pointer to an application-defined memory reallocation function.

- `pfnFree` is a PFN_vkFreeFunction pointer to an application-defined memory free function.

- `pfnInternalAllocation` is a PFN_vkInternalAllocationNotification pointer to an application-defined function that is called by the implementation when the implementation makes internal allocations.

- `pfnInternalFree` is a PFN_vkInternalFreeNotification pointer to an application-defined function that is called by the implementation when the implementation frees internal allocations.

Valid Usage

- `pfnAllocation` must be a valid pointer to a valid user-defined PFN_vkAllocationFunction

- `pfnReallocation` must be a valid pointer to a valid user-defined PFN_vkReallocationFunction

- `pfnFree` must be a valid pointer to a valid user-defined PFN_vkFreeFunction

- If either of `pfnInternalAllocation` or `pfnInternalFree` is not `NULL`, both must be valid callbacks

The type of `pfnAllocation` is:

    typedef void* (VKAPI_PTR *PFN_vkAllocationFunction)(
        void*                                       pUserData,
        size_t                                      size,
        size_t                                      alignment,
        VkSystemAllocationScope                     allocationScope);

- `pUserData` is the value specified for VkAllocationCallbacks::`pUserData` in the allocator specified by the application.

- `size` is the size in bytes of the requested allocation.

- `alignment` is the requested alignment of the allocation in bytes and must be a power of two.

- `allocationScope` is a VkSystemAllocationScope value specifying the allocation scope of the lifetime of the allocation, as described here.

If `pfnAllocation` is unable to allocate the requested memory, it must return `NULL`. If the allocation was successful, it must return a valid pointer to memory allocation containing at least `size` bytes, and with the pointer value being a multiple of `alignment`.

| Note Correct Vulkan operation cannot be assumed if the application does not follow these rules. For example, `pfnAllocation` (or `pfnReallocation`) could cause termination of running Vulkan instance(s) on a failed allocation for debugging purposes, either directly or indirectly. In these circumstances, it cannot be assumed that any part of any affected VkInstance objects are going to operate correctly (even vkDestroyInstance), and the application must ensure it cleans up properly via other means (e.g. process termination).

If `pfnAllocation` returns `NULL`, and if the implementation is unable to continue correct processing of the current command without the requested allocation, it must treat this as a run-time error, and generate `VK_ERROR_OUT_OF_HOST_MEMORY` at the appropriate time for the command in which the condition was detected, as described in Return Codes.

If the implementation is able to continue correct processing of the current command without the requested allocation, then it may do so, and must not generate `VK_ERROR_OUT_OF_HOST_MEMORY` as a result of this failed allocation.

The type of `pfnReallocation` is:

    typedef void* (VKAPI_PTR *PFN_vkReallocationFunction)(
        void*                                       pUserData,
        void*                                       pOriginal,
        size_t                                      size,
        size_t                                      alignment,
        VkSystemAllocationScope                     allocationScope);

- `pUserData` is the value specified for VkAllocationCallbacks::`pUserData` in the allocator specified by the application.

- `pOriginal` must be either `NULL` or a pointer previously returned by `pfnReallocation` or `pfnAllocation` of a compatible allocator.

- `size` is the size in bytes of the requested allocation.

- `alignment` is the requested alignment of the allocation in bytes and must be a power of two.

- `allocationScope` is a VkSystemAllocationScope value specifying the allocation scope of the lifetime of the allocation, as described here.

`pfnReallocation` must return an allocation with enough space for `size` bytes, and the contents of the original allocation from bytes zero to min(original size, new size) - 1 must be preserved in the returned allocation. If `size` is larger than the old size, the contents of the additional space are undefined. If satisfying these requirements involves creating a new allocation, then the old allocation should be freed.

If `pOriginal` is `NULL`, then `pfnReallocation` must behave equivalently to a call to PFN_vkAllocationFunction with the same parameter values (without `pOriginal`).

If `size` is zero, then `pfnReallocation` must behave equivalently to a call to PFN_vkFreeFunction with the same `pUserData` parameter value, and `pMemory` equal to `pOriginal`.

If `pOriginal` is non-`NULL`, the implementation must ensure that `alignment` is equal to the `alignment` used to originally allocate `pOriginal`.

If this function fails and `pOriginal` is non-`NULL` the application must not free the old allocation.

`pfnReallocation` must follow the same rules for return values as `PFN_vkAllocationFunction`.

The type of `pfnFree` is:

    typedef void (VKAPI_PTR *PFN_vkFreeFunction)(
        void*                                       pUserData,
        void*                                       pMemory);

- `pUserData` is the value specified for VkAllocationCallbacks::`pUserData` in the allocator specified by the application.

- `pMemory` is the allocation to be freed.

`pMemory` may be `NULL`, which the callback must handle safely. If `pMemory` is non-`NULL`, it must be a pointer previously allocated by `pfnAllocation` or `pfnReallocation`. The application should free this memory.

The type of `pfnInternalAllocation` is:

    typedef void (VKAPI_PTR *PFN_vkInternalAllocationNotification)(
        void*                                       pUserData,
        size_t                                      size,
        VkInternalAllocationType                    allocationType,
        VkSystemAllocationScope                     allocationScope);

- `pUserData` is the value specified for VkAllocationCallbacks::`pUserData` in the allocator specified by the application.

- `size` is the requested size of an allocation.

- `allocationType` is a VkInternalAllocationType value specifying the requested type of an allocation.

- `allocationScope` is a VkSystemAllocationScope value specifying the allocation scope of the lifetime of the allocation, as described here.

This is a purely informational callback.

The type of `pfnInternalFree` is:

    typedef void (VKAPI_PTR *PFN_vkInternalFreeNotification)(
        void*                                       pUserData,
        size_t                                      size,
        VkInternalAllocationType                    allocationType,
        VkSystemAllocationScope                     allocationScope);

- `pUserData` is the value specified for VkAllocationCallbacks::`pUserData` in the allocator specified by the application.

- `size` is the requested size of an allocation.

- `allocationType` is a VkInternalAllocationType value specifying the requested type of an allocation.

- `allocationScope` is a VkSystemAllocationScope value specifying the allocation scope of the lifetime of the allocation, as described here.

Each allocation has an allocation scope defining its lifetime and which object it is associated with. Possible values passed to the `allocationScope` parameter of the callback functions specified by VkAllocationCallbacks, indicating the allocation scope, are:

    typedef enum VkSystemAllocationScope {
        VK_SYSTEM_ALLOCATION_SCOPE_COMMAND = 0,
        VK_SYSTEM_ALLOCATION_SCOPE_OBJECT = 1,
        VK_SYSTEM_ALLOCATION_SCOPE_CACHE = 2,
        VK_SYSTEM_ALLOCATION_SCOPE_DEVICE = 3,
        VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE = 4,
        VK_SYSTEM_ALLOCATION_SCOPE_MAX_ENUM = 0x7FFFFFFF
    } VkSystemAllocationScope;

- `VK_SYSTEM_ALLOCATION_SCOPE_COMMAND` specifies that the allocation is scoped to the duration of the Vulkan command.

- `VK_SYSTEM_ALLOCATION_SCOPE_OBJECT` specifies that the allocation is scoped to the lifetime of the Vulkan object that is being created or used.

- `VK_SYSTEM_ALLOCATION_SCOPE_CACHE` specifies that the allocation is scoped to the lifetime of a `VkPipelineCache` or `VkValidationCacheEXT` object.

- `VK_SYSTEM_ALLOCATION_SCOPE_DEVICE` specifies that the allocation is scoped to the lifetime of the Vulkan device.

- `VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE` specifies that the allocation is scoped to the lifetime of the Vulkan instance.

Most Vulkan commands operate on a single object, or there is a sole object that is being created or manipulated. When an allocation uses an allocation scope of `VK_SYSTEM_ALLOCATION_SCOPE_OBJECT` or `VK_SYSTEM_ALLOCATION_SCOPE_CACHE`, the allocation is scoped to the object being created or manipulated.

When an implementation requires host memory, it will make callbacks to the application using the most specific allocator and allocation scope available:

- If an allocation is scoped to the duration of a command, the allocator will use the `VK_SYSTEM_ALLOCATION_SCOPE_COMMAND` allocation scope. The most specific allocator available is used: if the object being created or manipulated has an allocator, that object’s allocator will be used, else if the parent `VkDevice` has an allocator it will be used, else if the parent `VkInstance` has an allocator it will be used. Else,

- If an allocation is associated with a `VkValidationCacheEXT` or `VkPipelineCache` object, the allocator will use the `VK_SYSTEM_ALLOCATION_SCOPE_CACHE` allocation scope. The most specific allocator available is used (cache, else device, else instance). Else,

- If an allocation is scoped to the lifetime of an object, that object is being created or manipulated by the command, and that object’s type is not `VkDevice` or `VkInstance`, the allocator will use an allocation scope of `VK_SYSTEM_ALLOCATION_SCOPE_OBJECT`. The most specific allocator available is used (object, else device, else instance). Else,

- If an allocation is scoped to the lifetime of a device, the allocator will use an allocation scope of `VK_SYSTEM_ALLOCATION_SCOPE_DEVICE`. The most specific allocator available is used (device, else instance). Else,

- If the allocation is scoped to the lifetime of an instance and the instance has an allocator, its allocator will be used with an allocation scope of `VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE`.

- Otherwise an implementation will allocate memory through an alternative mechanism that is unspecified.

Objects that are allocated from pools do not specify their own allocator. When an implementation requires host memory for such an object, that memory is sourced from the object’s parent pool’s allocator.

The application is not expected to handle allocating memory that is intended for execution by the host due to the complexities of differing security implementations across multiple platforms. The implementation will allocate such memory internally and invoke an application provided informational callback when these internal allocations are allocated and freed. Upon allocation of executable memory, `pfnInternalAllocation` will be called. Upon freeing executable memory, `pfnInternalFree` will be called. An implementation will only call an informational callback for executable memory allocations and frees.

The `allocationType` parameter to the `pfnInternalAllocation` and `pfnInternalFree` functions may be one of the following values:

    typedef enum VkInternalAllocationType {
        VK_INTERNAL_ALLOCATION_TYPE_EXECUTABLE = 0,
        VK_INTERNAL_ALLOCATION_TYPE_MAX_ENUM = 0x7FFFFFFF
    } VkInternalAllocationType;

- `VK_INTERNAL_ALLOCATION_TYPE_EXECUTABLE` specifies that the allocation is intended for execution by the host.

An implementation must only make calls into an application-provided allocator during the execution of an API command. An implementation must only make calls into an application-provided allocator from the same thread that called the provoking API command. The implementation should not synchronize calls to any of the callbacks. If synchronization is needed, the callbacks must provide it themselves. The informational callbacks are subject to the same restrictions as the allocation callbacks.

If an implementation intends to make calls through a `VkAllocationCallbacks` structure between the time a `vkCreate*` command returns and the time a corresponding `vkDestroy*` command begins, that implementation must save a copy of the allocator before the `vkCreate*` command returns. The callback functions and any data structures they rely upon must remain valid for the lifetime of the object they are associated with.

If an allocator is provided to a `vkCreate*` command, a compatible allocator must be provided to the corresponding `vkDestroy*` command. Two `VkAllocationCallbacks` structures are compatible if memory allocated with `pfnAllocation` or `pfnReallocation` in each can be freed with `pfnReallocation` or `pfnFree` in the other. An allocator must not be provided to a `vkDestroy*` command if an allocator was not provided to the corresponding `vkCreate*` command.

If a non-`NULL` allocator is used, the `pfnAllocation`, `pfnReallocation` and `pfnFree` members must be non-`NULL` and point to valid implementations of the callbacks. An application can choose to not provide informational callbacks by setting both `pfnInternalAllocation` and `pfnInternalFree` to `NULL`. `pfnInternalAllocation` and `pfnInternalFree` must either both be `NULL` or both be non-`NULL`.

If `pfnAllocation` or `pfnReallocation` fail, the implementation may fail object creation and/or generate a `VK_ERROR_OUT_OF_HOST_MEMORY` error, as appropriate.

Allocation callbacks must not call any Vulkan commands.

The following sets of rules define when an implementation is permitted to call the allocator callbacks.

`pfnAllocation` or `pfnReallocation` may be called in the following situations:

- Allocations scoped to a `VkDevice` or `VkInstance` may be allocated from any API command.

- Allocations scoped to a command may be allocated from any API command.

- Allocations scoped to a `VkPipelineCache` may only be allocated from:

  - `vkCreatePipelineCache`

  - `vkMergePipelineCaches` for `dstCache`

  - `vkCreateGraphicsPipelines` for `pipelineCache`

  - `vkCreateComputePipelines` for `pipelineCache`

- Allocations scoped to a `VkValidationCacheEXT` may only be allocated from:

  - `vkCreateValidationCacheEXT`

  - `vkMergeValidationCachesEXT` for `dstCache`

  - `vkCreateShaderModule` for `validationCache` in `VkShaderModuleValidationCacheCreateInfoEXT`

- Allocations scoped to a `VkDescriptorPool` may only be allocated from:

  - any command that takes the pool as a direct argument

  - `vkAllocateDescriptorSets` for the `descriptorPool` member of its `pAllocateInfo` parameter

  - `vkCreateDescriptorPool`

- Allocations scoped to a `VkCommandPool` may only be allocated from:

  - any command that takes the pool as a direct argument

  - `vkCreateCommandPool`

  - `vkAllocateCommandBuffers` for the `commandPool` member of its `pAllocateInfo` parameter

  - any `vkCmd*` command whose `commandBuffer` was allocated from that `VkCommandPool`

- Allocations scoped to any other object may only be allocated in that object’s `vkCreate*` command.

`pfnFree`, or `pfnReallocation` with zero `size`, may be called in the following situations:

- Allocations scoped to a `VkDevice` or `VkInstance` may be freed from any API command.

- Allocations scoped to a command must be freed by any API command which allocates such memory.

- Allocations scoped to a `VkPipelineCache` may be freed from `vkDestroyPipelineCache`.

- Allocations scoped to a `VkValidationCacheEXT` may be freed from `vkDestroyValidationCacheEXT`.

- Allocations scoped to a `VkDescriptorPool` may be freed from

  - any command that takes the pool as a direct argument

- Allocations scoped to a `VkCommandPool` may be freed from:

  - any command that takes the pool as a direct argument

  - `vkResetCommandBuffer` whose `commandBuffer` was allocated from that `VkCommandPool`

- Allocations scoped to any other object may be freed in that object’s `vkDestroy*` command.

- Any command that allocates host memory may also free host memory of the same scope.

### 10.2. Device Memory

Device memory is memory that is visible to the device — for example the contents of the image or buffer objects, which can be natively used by the device.

Memory properties of a physical device describe the memory heaps and memory types available.

To query memory properties, call:

    void vkGetPhysicalDeviceMemoryProperties(
        VkPhysicalDevice                            physicalDevice,
        VkPhysicalDeviceMemoryProperties*           pMemoryProperties);

- `physicalDevice` is the handle to the device to query.

- `pMemoryProperties` is a pointer to a VkPhysicalDeviceMemoryProperties structure in which the properties are returned.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pMemoryProperties` must be a valid pointer to a VkPhysicalDeviceMemoryProperties structure

The `VkPhysicalDeviceMemoryProperties` structure is defined as:

    typedef struct VkPhysicalDeviceMemoryProperties {
        uint32_t        memoryTypeCount;
        VkMemoryType    memoryTypes[VK_MAX_MEMORY_TYPES];
        uint32_t        memoryHeapCount;
        VkMemoryHeap    memoryHeaps[VK_MAX_MEMORY_HEAPS];
    } VkPhysicalDeviceMemoryProperties;

- `memoryTypeCount` is the number of valid elements in the `memoryTypes` array.

- `memoryTypes` is an array of `VK_MAX_MEMORY_TYPES` VkMemoryType structures describing the memory types that can be used to access memory allocated from the heaps specified by `memoryHeaps`.

- `memoryHeapCount` is the number of valid elements in the `memoryHeaps` array.

- `memoryHeaps` is an array of `VK_MAX_MEMORY_HEAPS` VkMemoryHeap structures describing the memory heaps from which memory can be allocated.

The `VkPhysicalDeviceMemoryProperties` structure describes a number of memory heaps as well as a number of memory types that can be used to access memory allocated in those heaps. Each heap describes a memory resource of a particular size, and each memory type describes a set of memory properties (e.g. host cached vs uncached) that can be used with a given memory heap. Allocations using a particular memory type will consume resources from the heap indicated by that memory type’s heap index. More than one memory type may share each heap, and the heaps and memory types provide a mechanism to advertise an accurate size of the physical memory resources while allowing the memory to be used with a variety of different properties.

The number of memory heaps is given by `memoryHeapCount` and is less than or equal to `VK_MAX_MEMORY_HEAPS`. Each heap is described by an element of the `memoryHeaps` array as a VkMemoryHeap structure. The number of memory types available across all memory heaps is given by `memoryTypeCount` and is less than or equal to `VK_MAX_MEMORY_TYPES`. Each memory type is described by an element of the `memoryTypes` array as a VkMemoryType structure.

At least one heap must include `VK_MEMORY_HEAP_DEVICE_LOCAL_BIT` in VkMemoryHeap::`flags`. If there are multiple heaps that all have similar performance characteristics, they may all include `VK_MEMORY_HEAP_DEVICE_LOCAL_BIT`. In a unified memory architecture (UMA) system there is often only a single memory heap which is considered to be equally “local” to the host and to the device, and such an implementation must advertise the heap as device-local.

Each memory type returned by vkGetPhysicalDeviceMemoryProperties must have its `propertyFlags` set to one of the following values:

- 0

- `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` |
  `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT`

- `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` |
  `VK_MEMORY_PROPERTY_HOST_CACHED_BIT`

- `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` |
  `VK_MEMORY_PROPERTY_HOST_CACHED_BIT` |
  `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT`

- `VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT`

- `VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT` |
  `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` |
  `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT`

- `VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT` |
  `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` |
  `VK_MEMORY_PROPERTY_HOST_CACHED_BIT`

- `VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT` |
  `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` |
  `VK_MEMORY_PROPERTY_HOST_CACHED_BIT` |
  `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT`

- `VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT` |
  `VK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BIT`

- `VK_MEMORY_PROPERTY_PROTECTED_BIT`

- `VK_MEMORY_PROPERTY_PROTECTED_BIT` | `VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT`

- `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` |
  `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT` |
  `VK_MEMORY_PROPERTY_DEVICE_COHERENT_BIT_AMD`

- `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` |
  `VK_MEMORY_PROPERTY_HOST_CACHED_BIT` |
  `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT` |
  `VK_MEMORY_PROPERTY_DEVICE_COHERENT_BIT_AMD`

- `VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT` |
  `VK_MEMORY_PROPERTY_DEVICE_COHERENT_BIT_AMD`

- `VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT` |
  `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` |
  `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT` |
  `VK_MEMORY_PROPERTY_DEVICE_COHERENT_BIT_AMD`

- `VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT` |
  `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` |
  `VK_MEMORY_PROPERTY_HOST_CACHED_BIT` |
  `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT` |
  `VK_MEMORY_PROPERTY_DEVICE_COHERENT_BIT_AMD`

- `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` |
  `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT` |
  `VK_MEMORY_PROPERTY_DEVICE_COHERENT_BIT_AMD` |
  `VK_MEMORY_PROPERTY_DEVICE_UNCACHED_BIT_AMD`

- `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` |
  `VK_MEMORY_PROPERTY_HOST_CACHED_BIT` |
  `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT` |
  `VK_MEMORY_PROPERTY_DEVICE_COHERENT_BIT_AMD` |
  `VK_MEMORY_PROPERTY_DEVICE_UNCACHED_BIT_AMD`

- `VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT` |
  `VK_MEMORY_PROPERTY_DEVICE_COHERENT_BIT_AMD` |
  `VK_MEMORY_PROPERTY_DEVICE_UNCACHED_BIT_AMD`

- `VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT` |
  `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` |
  `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT` |
  `VK_MEMORY_PROPERTY_DEVICE_COHERENT_BIT_AMD` |
  `VK_MEMORY_PROPERTY_DEVICE_UNCACHED_BIT_AMD`

- `VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT` |
  `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` |
  `VK_MEMORY_PROPERTY_HOST_CACHED_BIT` |
  `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT` |
  `VK_MEMORY_PROPERTY_DEVICE_COHERENT_BIT_AMD` |
  `VK_MEMORY_PROPERTY_DEVICE_UNCACHED_BIT_AMD`

There must be at least one memory type with both the `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` and `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT` bits set in its `propertyFlags`. There must be at least one memory type with the `VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT` bit set in its `propertyFlags`. If the `deviceCoherentMemory` feature is enabled, there must be at least one memory type with the `VK_MEMORY_PROPERTY_DEVICE_COHERENT_BIT_AMD` bit set in its `propertyFlags`.

For each pair of elements X and Y returned in `memoryTypes`, X must be placed at a lower index position than Y if:

- either the set of bit flags returned in the `propertyFlags` member of X is a strict subset of the set of bit flags returned in the `propertyFlags` member of Y; or

- the `propertyFlags` members of X and Y are equal, and X belongs to a memory heap with greater performance (as determined in an implementation-specific manner) ; or

- or the `propertyFlags` members of X includes `VK_MEMORY_PROPERTY_DEVICE_COHERENT_BIT_AMD` or `VK_MEMORY_PROPERTY_DEVICE_UNCACHED_BIT_AMD` and Y does not

| Note There is no ordering requirement between X and Y elements for the case their `propertyFlags` members are not in a subset relation. That potentially allows more than one possible way to order the same set of memory types. Notice that the list of all allowed memory property flag combinations is written in a valid order. But if instead `VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT` was before `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` | `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT`, the list would still be in a valid order. There may be a performance penalty for using device coherent or uncached device memory types, and using these accidentally is undesirable. In order to avoid this, memory types with these properties always appear at the end of the list; but are subject to the same rules otherwise.

This ordering requirement enables applications to use a simple search loop to select the desired memory type along the lines of:

    // Find a memory in `memoryTypeBitsRequirement` that includes all of `requiredProperties`
    int32_t findProperties(const VkPhysicalDeviceMemoryProperties* pMemoryProperties,
                           uint32_t memoryTypeBitsRequirement,
                           VkMemoryPropertyFlags requiredProperties) {
        const uint32_t memoryCount = pMemoryProperties->memoryTypeCount;
        for (uint32_t memoryIndex = 0; memoryIndex < memoryCount; ++memoryIndex) {
            const uint32_t memoryTypeBits = (1 << memoryIndex);
            const bool isRequiredMemoryType = memoryTypeBitsRequirement & memoryTypeBits;

            const VkMemoryPropertyFlags properties =
                pMemoryProperties->memoryTypes[memoryIndex].propertyFlags;
            const bool hasRequiredProperties =
                (properties & requiredProperties) == requiredProperties;

            if (isRequiredMemoryType && hasRequiredProperties)
                return static_cast<int32_t>(memoryIndex);
        }

        // failed to find memory type
        return -1;
    }

    // Try to find an optimal memory type, or if it does not exist try fallback memory type
    // `device` is the VkDevice
    // `image` is the VkImage that requires memory to be bound
    // `memoryProperties` properties as returned by vkGetPhysicalDeviceMemoryProperties
    // `requiredProperties` are the property flags that must be present
    // `optimalProperties` are the property flags that are preferred by the application
    VkMemoryRequirements memoryRequirements;
    vkGetImageMemoryRequirements(device, image, &memoryRequirements);
    int32_t memoryType =
        findProperties(&memoryProperties, memoryRequirements.memoryTypeBits, optimalProperties);
    if (memoryType == -1) // not found; try fallback properties
        memoryType =
            findProperties(&memoryProperties, memoryRequirements.memoryTypeBits, requiredProperties);

To query memory properties, call:

    void vkGetPhysicalDeviceMemoryProperties2(
        VkPhysicalDevice                            physicalDevice,
        VkPhysicalDeviceMemoryProperties2*          pMemoryProperties);

or the equivalent command

    void vkGetPhysicalDeviceMemoryProperties2KHR(
        VkPhysicalDevice                            physicalDevice,
        VkPhysicalDeviceMemoryProperties2*          pMemoryProperties);

- `physicalDevice` is the handle to the device to query.

- `pMemoryProperties` is a pointer to a VkPhysicalDeviceMemoryProperties2 structure in which the properties are returned.

`vkGetPhysicalDeviceMemoryProperties2` behaves similarly to vkGetPhysicalDeviceMemoryProperties, with the ability to return extended information in a `pNext` chain of output structures.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pMemoryProperties` must be a valid pointer to a VkPhysicalDeviceMemoryProperties2 structure

The `VkPhysicalDeviceMemoryProperties2` structure is defined as:

    typedef struct VkPhysicalDeviceMemoryProperties2 {
        VkStructureType                     sType;
        void*                               pNext;
        VkPhysicalDeviceMemoryProperties    memoryProperties;
    } VkPhysicalDeviceMemoryProperties2;

or the equivalent

    typedef VkPhysicalDeviceMemoryProperties2 VkPhysicalDeviceMemoryProperties2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `memoryProperties` is a VkPhysicalDeviceMemoryProperties structure which is populated with the same values as in vkGetPhysicalDeviceMemoryProperties.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_PROPERTIES_2`

- `pNext` must be `NULL` or a pointer to a valid instance of VkPhysicalDeviceMemoryBudgetPropertiesEXT

- The `sType` value of each struct in the `pNext` chain must be unique

The `VkMemoryHeap` structure is defined as:

    typedef struct VkMemoryHeap {
        VkDeviceSize         size;
        VkMemoryHeapFlags    flags;
    } VkMemoryHeap;

- `size` is the total memory size in bytes in the heap.

- `flags` is a bitmask of VkMemoryHeapFlagBits specifying attribute flags for the heap.

Bits which may be set in VkMemoryHeap::`flags`, indicating attribute flags for the heap, are:

    typedef enum VkMemoryHeapFlagBits {
        VK_MEMORY_HEAP_DEVICE_LOCAL_BIT = 0x00000001,
        VK_MEMORY_HEAP_MULTI_INSTANCE_BIT = 0x00000002,
        VK_MEMORY_HEAP_MULTI_INSTANCE_BIT_KHR = VK_MEMORY_HEAP_MULTI_INSTANCE_BIT,
        VK_MEMORY_HEAP_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkMemoryHeapFlagBits;

- `VK_MEMORY_HEAP_DEVICE_LOCAL_BIT` specifies that the heap corresponds to device local memory. Device local memory may have different performance characteristics than host local memory, and may support different memory property flags.

- `VK_MEMORY_HEAP_MULTI_INSTANCE_BIT` specifies that in a logical device representing more than one physical device, there is a per-physical device instance of the heap memory. By default, an allocation from such a heap will be replicated to each physical device’s instance of the heap.

    typedef VkFlags VkMemoryHeapFlags;

`VkMemoryHeapFlags` is a bitmask type for setting a mask of zero or more VkMemoryHeapFlagBits.

The `VkMemoryType` structure is defined as:

    typedef struct VkMemoryType {
        VkMemoryPropertyFlags    propertyFlags;
        uint32_t                 heapIndex;
    } VkMemoryType;

- `heapIndex` describes which memory heap this memory type corresponds to, and must be less than `memoryHeapCount` from the VkPhysicalDeviceMemoryProperties structure.

- `propertyFlags` is a bitmask of VkMemoryPropertyFlagBits of properties for this memory type.

Bits which may be set in VkMemoryType::`propertyFlags`, indicating properties of a memory heap, are:

    typedef enum VkMemoryPropertyFlagBits {
        VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT = 0x00000001,
        VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT = 0x00000002,
        VK_MEMORY_PROPERTY_HOST_COHERENT_BIT = 0x00000004,
        VK_MEMORY_PROPERTY_HOST_CACHED_BIT = 0x00000008,
        VK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BIT = 0x00000010,
        VK_MEMORY_PROPERTY_PROTECTED_BIT = 0x00000020,
        VK_MEMORY_PROPERTY_DEVICE_COHERENT_BIT_AMD = 0x00000040,
        VK_MEMORY_PROPERTY_DEVICE_UNCACHED_BIT_AMD = 0x00000080,
        VK_MEMORY_PROPERTY_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkMemoryPropertyFlagBits;

- `VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT` bit specifies that memory allocated with this type is the most efficient for device access. This property will be set if and only if the memory type belongs to a heap with the `VK_MEMORY_HEAP_DEVICE_LOCAL_BIT` set.

- `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` bit specifies that memory allocated with this type can be mapped for host access using vkMapMemory.

- `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT` bit specifies that the host cache management commands vkFlushMappedMemoryRanges and vkInvalidateMappedMemoryRanges are not needed to flush host writes to the device or make device writes visible to the host, respectively.

- `VK_MEMORY_PROPERTY_HOST_CACHED_BIT` bit specifies that memory allocated with this type is cached on the host. Host memory accesses to uncached memory are slower than to cached memory, however uncached memory is always host coherent.

- `VK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BIT` bit specifies that the memory type only allows device access to the memory. Memory types must not have both `VK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BIT` and `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` set. Additionally, the object’s backing memory may be provided by the implementation lazily as specified in Lazily Allocated Memory.

- `VK_MEMORY_PROPERTY_PROTECTED_BIT` bit specifies that the memory type only allows device access to the memory, and allows protected queue operations to access the memory. Memory types must not have `VK_MEMORY_PROPERTY_PROTECTED_BIT` set and any of `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` set, or `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT` set, or `VK_MEMORY_PROPERTY_HOST_CACHED_BIT` set.

- `VK_MEMORY_PROPERTY_DEVICE_COHERENT_BIT_AMD` bit specifies that device accesses to allocations of this memory type are automatically made available and visible.

- `VK_MEMORY_PROPERTY_DEVICE_UNCACHED_BIT_AMD` bit specifies that memory allocated with this type is not cached on the device. Uncached device memory is always device coherent.

For any memory allocated with both the `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT` and the `VK_MEMORY_PROPERTY_DEVICE_COHERENT_BIT_AMD`, host or device accesses also perform automatic memory domain transfer operations, such that writes are always automatically available and visible to both host and device memory domains.

| Note Device coherence is a useful property for certain debugging use cases (e.g. crash analysis, where performing separate coherence actions could mean values are not reported correctly). However, device coherent accesses may be slower than equivalent accesses without device coherence, particularly if they are also device uncached. For device uncached memory in particular, repeated accesses to the same or neighbouring memory locations over a short time period (e.g. within a frame) may be slower than it would be for the equivalent cached memory type. As such, it’s generally inadvisable to use device coherent or device uncached memory except when really needed.

    typedef VkFlags VkMemoryPropertyFlags;

`VkMemoryPropertyFlags` is a bitmask type for setting a mask of zero or more VkMemoryPropertyFlagBits.

If the `VkPhysicalDeviceMemoryBudgetPropertiesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceMemoryProperties2, it is filled with the current memory budgets and usages.

The `VkPhysicalDeviceMemoryBudgetPropertiesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceMemoryBudgetPropertiesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkDeviceSize       heapBudget[VK_MAX_MEMORY_HEAPS];
        VkDeviceSize       heapUsage[VK_MAX_MEMORY_HEAPS];
    } VkPhysicalDeviceMemoryBudgetPropertiesEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `heapBudget` is an array of `VK_MAX_MEMORY_HEAPS` `VkDeviceSize` values in which memory budgets are returned, with one element for each memory heap. A heap’s budget is a rough estimate of how much memory the process can allocate from that heap before allocations may fail or cause performance degradation. The budget includes any currently allocated device memory.

- `heapUsage` is an array of `VK_MAX_MEMORY_HEAPS` `VkDeviceSize` values in which memory usages are returned, with one element for each memory heap. A heap’s usage is an estimate of how much memory the process is currently using in that heap.

The values returned in this structure are not invariant. The `heapBudget` and `heapUsage` values must be zero for array elements greater than or equal to VkPhysicalDeviceMemoryProperties::`memoryHeapCount`. The `heapBudget` value must be non-zero for array elements less than VkPhysicalDeviceMemoryProperties::`memoryHeapCount`. The `heapBudget` value must be less than or equal to VkMemoryHeap::`size` for each heap.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_BUDGET_PROPERTIES_EXT`

A Vulkan device operates on data in device memory via memory objects that are represented in the API by a `VkDeviceMemory` handle:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkDeviceMemory)

To allocate memory objects, call:

    VkResult vkAllocateMemory(
        VkDevice                                    device,
        const VkMemoryAllocateInfo*                 pAllocateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkDeviceMemory*                             pMemory);

- `device` is the logical device that owns the memory.

- `pAllocateInfo` is a pointer to a VkMemoryAllocateInfo structure describing parameters of the allocation. A successful returned allocation must use the requested parameters — no substitution is permitted by the implementation.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pMemory` is a pointer to a VkDeviceMemory handle in which information about the allocated memory is returned.

Allocations returned by `vkAllocateMemory` are guaranteed to meet any alignment requirement of the implementation. For example, if an implementation requires 128 byte alignment for images and 64 byte alignment for buffers, the device memory returned through this mechanism would be 128-byte aligned. This ensures that applications can correctly suballocate objects of different types (with potentially different alignment requirements) in the same memory object.

When memory is allocated, its contents are undefined with the following constraint:

- The contents of unprotected memory must not be a function of data protected memory objects, even if those memory objects were previously freed.

| Note The contents of memory allocated by one application should not be a function of data from protected memory objects of another application, even if those memory objects were previously freed.

The maximum number of valid memory allocations that can exist simultaneously within a VkDevice may be restricted by implementation- or platform-dependent limits. If a call to vkAllocateMemory would cause the total number of allocations to exceed these limits, such a call will fail and must return `VK_ERROR_TOO_MANY_OBJECTS`. The `maxMemoryAllocationCount` feature describes the number of allocations that can exist simultaneously before encountering these internal limits.

Some platforms may have a limit on the maximum size of a single allocation. For example, certain systems may fail to create allocations with a size greater than or equal to 4GB. Such a limit is implementation-dependent, and if such a failure occurs then the error `VK_ERROR_OUT_OF_DEVICE_MEMORY` must be returned. This limit is advertised in VkPhysicalDeviceMaintenance3Properties::`maxMemoryAllocationSize`.

The cumulative memory size allocated to a heap can be limited by the size of the specified heap. In such cases, allocated memory is tracked on a per-device and per-heap basis. Some platforms allow overallocation into other heaps. The overallocation behavior can be specified through the `VK_AMD_memory_overallocation_behavior` extension.

Valid Usage

- `pAllocateInfo->allocationSize` must be less than or equal to VkPhysicalDeviceMemoryProperties::`memoryHeaps`[memindex].size where `memindex` = VkPhysicalDeviceMemoryProperties::`memoryTypes`[pAllocateInfo->memoryTypeIndex].heapIndex as returned by vkGetPhysicalDeviceMemoryProperties for the VkPhysicalDevice that `device` was created from.

- `pAllocateInfo->memoryTypeIndex` must be less than VkPhysicalDeviceMemoryProperties::`memoryTypeCount` as returned by vkGetPhysicalDeviceMemoryProperties for the VkPhysicalDevice that `device` was created from.

- If the `deviceCoherentMemory` feature is not enabled, `pAllocateInfo->memoryTypeIndex` must not identify a memory type supporting `VK_MEMORY_PROPERTY_DEVICE_COHERENT_BIT_AMD`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pAllocateInfo` must be a valid pointer to a valid VkMemoryAllocateInfo structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pMemory` must be a valid pointer to a VkDeviceMemory handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_TOO_MANY_OBJECTS`

  - `VK_ERROR_INVALID_EXTERNAL_HANDLE`

  - `VK_ERROR_INVALID_OPAQUE_CAPTURE_ADDRESS_KHR`

The `VkMemoryAllocateInfo` structure is defined as:

    typedef struct VkMemoryAllocateInfo {
        VkStructureType    sType;
        const void*        pNext;
        VkDeviceSize       allocationSize;
        uint32_t           memoryTypeIndex;
    } VkMemoryAllocateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `allocationSize` is the size of the allocation in bytes

- `memoryTypeIndex` is an index identifying a memory type from the `memoryTypes` array of the VkPhysicalDeviceMemoryProperties structure

A `VkMemoryAllocateInfo` structure defines a memory import operation if its `pNext` chain includes one of the following structures:

- VkImportMemoryWin32HandleInfoKHR with non-zero `handleType` value

- VkImportMemoryFdInfoKHR with a non-zero `handleType` value

- VkImportMemoryHostPointerInfoEXT with a non-zero `handleType` value

- VkImportAndroidHardwareBufferInfoANDROID with a non-`NULL` `buffer` value

Importing memory must not modify the content of the memory. Implementations must ensure that importing memory does not enable the importing Vulkan instance to access any memory or resources in other Vulkan instances other than that corresponding to the memory object imported. Implementations must also ensure accessing imported memory which has not been initialized does not allow the importing Vulkan instance to obtain data from the exporting Vulkan instance or vice-versa.

| Note How exported and imported memory is isolated is left to the implementation, but applications should be aware that such isolation may prevent implementations from placing multiple exportable memory objects in the same physical or virtual page. Hence, applications should avoid creating many small external memory objects whenever possible.

When performing a memory import operation, it is the responsibility of the application to ensure the external handles meet all valid usage requirements. However, implementations must perform sufficient validation of external handles to ensure that the operation results in a valid memory object which will not cause program termination, device loss, queue stalls, or corruption of other resources when used as allowed according to its allocation parameters. If the external handle provided does not meet these requirements, the implementation must fail the memory import operation with the error code `VK_ERROR_INVALID_EXTERNAL_HANDLE`.

Valid Usage

- If the `pNext` chain includes a `VkExportMemoryAllocateInfo` structure, and any of the handle types specified in `VkExportMemoryAllocateInfo`::`handleTypes` require a dedicated allocation, as reported by vkGetPhysicalDeviceImageFormatProperties2 in `VkExternalImageFormatProperties`::`externalMemoryProperties.externalMemoryFeatures` or `VkExternalBufferProperties`::`externalMemoryProperties.externalMemoryFeatures`, the `pNext` chain must include a VkMemoryDedicatedAllocateInfo or VkDedicatedAllocationMemoryAllocateInfoNV structure with either its `image` or `buffer` member set to a value other than VK_NULL_HANDLE.

- If the `pNext` chain includes a VkExportMemoryAllocateInfo structure, it must not include a VkExportMemoryAllocateInfoNV or VkExportMemoryWin32HandleInfoNV structure.

- If the `pNext` chain includes a VkImportMemoryWin32HandleInfoKHR structure, it must not include a VkImportMemoryWin32HandleInfoNV structure.

- If the parameters define an import operation, the external handle specified was created by the Vulkan API, and the external handle type is `VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_FD_BIT_KHR`, then the values of `allocationSize` and `memoryTypeIndex` must match those specified when the memory object being imported was created.

- If the parameters define an import operation and the external handle specified was created by the Vulkan API, the device mask specified by VkMemoryAllocateFlagsInfo must match that specified when the memory object being imported was allocated.

- If the parameters define an import operation and the external handle specified was created by the Vulkan API, the list of physical devices that comprise the logical device passed to vkAllocateMemory must match the list of physical devices that comprise the logical device on which the memory was originally allocated.

- If the parameters define an import operation and the external handle is an NT handle or a global share handle created outside of the Vulkan API, the value of `memoryTypeIndex` must be one of those returned by vkGetMemoryWin32HandlePropertiesKHR.

- If the parameters define an import operation, the external handle was created by the Vulkan API, and the external handle type is `VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT_KHR` or `VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT_KHR`, then the values of `allocationSize` and `memoryTypeIndex` must match those specified when the memory object being imported was created.

- If the parameters define an import operation and the external handle type is `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_BIT`, `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_KMT_BIT`, or `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_RESOURCE_BIT`, `allocationSize` must match the size reported in the memory requirements of the `image` or `buffer` member of the `VkDedicatedAllocationMemoryAllocateInfoNV` structure included in the `pNext` chain.

- If the parameters define an import operation and the external handle type is `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_HEAP_BIT`, `allocationSize` must match the size specified when creating the Direct3D 12 heap from which the external handle was extracted.

- If the parameters define an import operation and the external handle is a POSIX file descriptor created outside of the Vulkan API, the value of `memoryTypeIndex` must be one of those returned by vkGetMemoryFdPropertiesKHR.

- If the protected memory feature is not enabled, the `VkMemoryAllocateInfo`::`memoryTypeIndex` must not indicate a memory type that reports `VK_MEMORY_PROPERTY_PROTECTED_BIT`.

- If the parameters define an import operation and the external handle is a host pointer, the value of `memoryTypeIndex` must be one of those returned by vkGetMemoryHostPointerPropertiesEXT

- If the parameters define an import operation and the external handle is a host pointer, `allocationSize` must be an integer multiple of `VkPhysicalDeviceExternalMemoryHostPropertiesEXT`::`minImportedHostPointerAlignment`

- If the parameters define an import operation and the external handle is a host pointer, the `pNext` chain must not include a VkDedicatedAllocationMemoryAllocateInfoNV structure with either its `image` or `buffer` field set to a value other than VK_NULL_HANDLE.

- If the parameters define an import operation and the external handle is a host pointer, the `pNext` chain must not include a VkMemoryDedicatedAllocateInfo structure with either its `image` or `buffer` field set to a value other than VK_NULL_HANDLE.

- If the parameters define an import operation and the external handle type is `VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID`, `allocationSize` must be the size returned by vkGetAndroidHardwareBufferPropertiesANDROID for the Android hardware buffer.

- If the parameters define an import operation and the external handle type is `VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID`, and the `pNext` chain does not include a VkMemoryDedicatedAllocateInfo structure or VkMemoryDedicatedAllocateInfo::`image` is VK_NULL_HANDLE, the Android hardware buffer must have a `AHardwareBuffer_Desc`::`format` of `AHARDWAREBUFFER_FORMAT_BLOB` and a `AHardwareBuffer_Desc`::`usage` that includes `AHARDWAREBUFFER_USAGE_GPU_DATA_BUFFER`.

- If the parameters define an import operation and the external handle type is `VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID`, `memoryTypeIndex` must be one of those returned by vkGetAndroidHardwareBufferPropertiesANDROID for the Android hardware buffer.

- If the parameters do not define an import operation, and the `pNext` chain includes a `VkExportMemoryAllocateInfo` structure with `VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID` included in its `handleTypes` member, and the `pNext` chain includes a VkMemoryDedicatedAllocateInfo structure with `image` not equal to VK_NULL_HANDLE, then `allocationSize` must be `0`, otherwise `allocationSize` must be greater than `0`.

- If the parameters define an import operation, the external handle is an Android hardware buffer, and the `pNext` chain includes a VkMemoryDedicatedAllocateInfo with `image` that is not VK_NULL_HANDLE, the Android hardware buffer’s AHardwareBuffer::`usage` must include at least one of `AHARDWAREBUFFER_USAGE_GPU_COLOR_OUTPUT` or `AHARDWAREBUFFER_USAGE_GPU_SAMPLED_IMAGE`.

- If the parameters define an import operation, the external handle is an Android hardware buffer, and the `pNext` chain includes a VkMemoryDedicatedAllocateInfo with `image` that is not VK_NULL_HANDLE, the format of `image` must be `VK_FORMAT_UNDEFINED` or the format returned by vkGetAndroidHardwareBufferPropertiesANDROID in VkAndroidHardwareBufferFormatPropertiesANDROID::`format` for the Android hardware buffer.

- If the parameters define an import operation, the external handle is an Android hardware buffer, and the `pNext` chain includes a VkMemoryDedicatedAllocateInfo structure with `image` that is not VK_NULL_HANDLE, the width, height, and array layer dimensions of `image` and the Android hardware buffer’s `AHardwareBuffer_Desc` must be identical.

- If the parameters define an import operation, the external handle is an Android hardware buffer, and the `pNext` chain includes a VkMemoryDedicatedAllocateInfo structure with `image` that is not VK_NULL_HANDLE, and the Android hardware buffer’s AHardwareBuffer::`usage` includes `AHARDWAREBUFFER_USAGE_GPU_MIPMAP_COMPLETE`, the `image` must have a complete mipmap chain.

- If the parameters define an import operation, the external handle is an Android hardware buffer, and the `pNext` chain includes a VkMemoryDedicatedAllocateInfo structure with `image` that is not VK_NULL_HANDLE, and the Android hardware buffer’s AHardwareBuffer::`usage` does not include `AHARDWAREBUFFER_USAGE_GPU_MIPMAP_COMPLETE`, the `image` must have exactly one mipmap level.

- If the parameters define an import operation, the external handle is an Android hardware buffer, and the `pNext` chain includes a VkMemoryDedicatedAllocateInfo structure with `image` that is not VK_NULL_HANDLE, each bit set in the usage of `image` must be listed in AHardwareBuffer Usage Equivalence, and if there is a corresponding `AHARDWAREBUFFER_USAGE` bit listed that bit must be included in the Android hardware buffer’s `AHardwareBuffer_Desc`::`usage`.

- If VkMemoryOpaqueCaptureAddressAllocateInfo::`opaqueCaptureAddress` is not zero, `VkMemoryAllocateFlagsInfo`::`flags` must include `VK_MEMORY_ALLOCATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT`

- If `VkMemoryAllocateFlagsInfo`::`flags` includes `VK_MEMORY_ALLOCATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT`, the bufferDeviceAddressCaptureReplay feature must be enabled

- If `VkMemoryAllocateFlagsInfo`::`flags` includes `VK_MEMORY_ALLOCATE_DEVICE_ADDRESS_BIT`, the bufferDeviceAddress feature must be enabled

- If the `pNext` chain includes a `VkImportMemoryHostPointerInfoEXT` structure, VkMemoryOpaqueCaptureAddressAllocateInfo::`opaqueCaptureAddress` must be zero

- If the parameters define an import operation, VkMemoryOpaqueCaptureAddressAllocateInfo::`opaqueCaptureAddress` must be zero

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkDedicatedAllocationMemoryAllocateInfoNV, VkExportMemoryAllocateInfo, VkExportMemoryAllocateInfoNV, VkExportMemoryWin32HandleInfoKHR, VkExportMemoryWin32HandleInfoNV, VkImportAndroidHardwareBufferInfoANDROID, VkImportMemoryFdInfoKHR, VkImportMemoryHostPointerInfoEXT, VkImportMemoryWin32HandleInfoKHR, VkImportMemoryWin32HandleInfoNV, VkMemoryAllocateFlagsInfo, VkMemoryDedicatedAllocateInfo, VkMemoryOpaqueCaptureAddressAllocateInfo, or VkMemoryPriorityAllocateInfoEXT

- The `sType` value of each struct in the `pNext` chain must be unique

If the `pNext` chain includes a `VkMemoryDedicatedAllocateInfo` structure, then that structure includes a handle of the sole buffer or image resource that the memory can be bound to.

The `VkMemoryDedicatedAllocateInfo` structure is defined as:

    typedef struct VkMemoryDedicatedAllocateInfo {
        VkStructureType    sType;
        const void*        pNext;
        VkImage            image;
        VkBuffer           buffer;
    } VkMemoryDedicatedAllocateInfo;

or the equivalent

    typedef VkMemoryDedicatedAllocateInfo VkMemoryDedicatedAllocateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `image` is VK_NULL_HANDLE or a handle of an image which this memory will be bound to.

- `buffer` is VK_NULL_HANDLE or a handle of a buffer which this memory will be bound to.

Valid Usage

- At least one of `image` and `buffer` must be VK_NULL_HANDLE

- If `image` is not VK_NULL_HANDLE, `VkMemoryAllocateInfo`::`allocationSize` must equal the `VkMemoryRequirements`::`size` of the image

- If `image` is not VK_NULL_HANDLE, `image` must have been created without `VK_IMAGE_CREATE_SPARSE_BINDING_BIT` set in `VkImageCreateInfo`::`flags`

- If `buffer` is not VK_NULL_HANDLE, `VkMemoryAllocateInfo`::`allocationSize` must equal the `VkMemoryRequirements`::`size` of the buffer

- If `buffer` is not VK_NULL_HANDLE, `buffer` must have been created without `VK_BUFFER_CREATE_SPARSE_BINDING_BIT` set in VkBufferCreateInfo::`flags`

- If `image` is not VK_NULL_HANDLE and VkMemoryAllocateInfo defines a memory import operation with handle type `VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT`, `VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT`, `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_BIT`, `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_KMT_BIT`, `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_HEAP_BIT`, or `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_RESOURCE_BIT`, and the external handle was created by the Vulkan API, then the memory being imported must also be a dedicated image allocation and `image` must be identical to the image associated with the imported memory.

- If `buffer` is not VK_NULL_HANDLE and VkMemoryAllocateInfo defines a memory import operation with handle type `VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT`, `VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT`, `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_BIT`, `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_KMT_BIT`, `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_HEAP_BIT`, or `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_RESOURCE_BIT`, and the external handle was created by the Vulkan API, then the memory being imported must also be a dedicated buffer allocation and `buffer` must be identical to the buffer associated with the imported memory.

- If `image` is not VK_NULL_HANDLE and VkMemoryAllocateInfo defines a memory import operation with handle type `VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_FD_BIT`, the memory being imported must also be a dedicated image allocation and `image` must be identical to the image associated with the imported memory.

- If `buffer` is not VK_NULL_HANDLE and VkMemoryAllocateInfo defines a memory import operation with handle type `VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_FD_BIT`, the memory being imported must also be a dedicated buffer allocation and `buffer` must be identical to the buffer associated with the imported memory.

- If `image` is not VK_NULL_HANDLE, `image` must not have been created with `VK_IMAGE_CREATE_DISJOINT_BIT` set in VkImageCreateInfo::`flags`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_MEMORY_DEDICATED_ALLOCATE_INFO`

- If `image` is not VK_NULL_HANDLE, `image` must be a valid VkImage handle

- If `buffer` is not VK_NULL_HANDLE, `buffer` must be a valid VkBuffer handle

- Both of `buffer`, and `image` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

If the `pNext` chain includes a `VkDedicatedAllocationMemoryAllocateInfoNV` structure, then that structure includes a handle of the sole buffer or image resource that the memory can be bound to.

The `VkDedicatedAllocationMemoryAllocateInfoNV` structure is defined as:

    typedef struct VkDedicatedAllocationMemoryAllocateInfoNV {
        VkStructureType    sType;
        const void*        pNext;
        VkImage            image;
        VkBuffer           buffer;
    } VkDedicatedAllocationMemoryAllocateInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `image` is VK_NULL_HANDLE or a handle of an image which this memory will be bound to.

- `buffer` is VK_NULL_HANDLE or a handle of a buffer which this memory will be bound to.

Valid Usage

- At least one of `image` and `buffer` must be VK_NULL_HANDLE

- If `image` is not VK_NULL_HANDLE, the image must have been created with `VkDedicatedAllocationImageCreateInfoNV`::`dedicatedAllocation` equal to `VK_TRUE`

- If `buffer` is not VK_NULL_HANDLE, the buffer must have been created with `VkDedicatedAllocationBufferCreateInfoNV`::`dedicatedAllocation` equal to `VK_TRUE`

- If `image` is not VK_NULL_HANDLE, `VkMemoryAllocateInfo`::`allocationSize` must equal the `VkMemoryRequirements`::`size` of the image

- If `buffer` is not VK_NULL_HANDLE, `VkMemoryAllocateInfo`::`allocationSize` must equal the `VkMemoryRequirements`::`size` of the buffer

- If `image` is not VK_NULL_HANDLE and VkMemoryAllocateInfo defines a memory import operation, the memory being imported must also be a dedicated image allocation and `image` must be identical to the image associated with the imported memory.

- If `buffer` is not VK_NULL_HANDLE and VkMemoryAllocateInfo defines a memory import operation, the memory being imported must also be a dedicated buffer allocation and `buffer` must be identical to the buffer associated with the imported memory.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_MEMORY_ALLOCATE_INFO_NV`

- If `image` is not VK_NULL_HANDLE, `image` must be a valid VkImage handle

- If `buffer` is not VK_NULL_HANDLE, `buffer` must be a valid VkBuffer handle

- Both of `buffer`, and `image` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

If the `pNext` chain includes a `VkMemoryPriorityAllocateInfoEXT` structure, then that structure includes a priority for the memory.

The `VkMemoryPriorityAllocateInfoEXT` structure is defined as:

    typedef struct VkMemoryPriorityAllocateInfoEXT {
        VkStructureType    sType;
        const void*        pNext;
        float              priority;
    } VkMemoryPriorityAllocateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `priority` is a floating-point value between `0` and `1`, indicating the priority of the allocation relative to other memory allocations. Larger values are higher priority. The granularity of the priorities is implementation-dependent.

Memory allocations with higher priority may be more likely to stay in device-local memory when the system is under memory pressure.

If this structure is not included, it is as if the `priority` value were `0.5`.

Valid Usage

- `priority` must be between `0` and `1`, inclusive

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_MEMORY_PRIORITY_ALLOCATE_INFO_EXT`

When allocating memory that may be exported to another process or Vulkan instance, add a VkExportMemoryAllocateInfo structure to the `pNext` chain of the VkMemoryAllocateInfo structure, specifying the handle types that may be exported.

The VkExportMemoryAllocateInfo structure is defined as:

    typedef struct VkExportMemoryAllocateInfo {
        VkStructureType                    sType;
        const void*                        pNext;
        VkExternalMemoryHandleTypeFlags    handleTypes;
    } VkExportMemoryAllocateInfo;

or the equivalent

    typedef VkExportMemoryAllocateInfo VkExportMemoryAllocateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `handleTypes` is a bitmask of VkExternalMemoryHandleTypeFlagBits specifying one or more memory handle types the application can export from the resulting allocation. The application can request multiple handle types for the same allocation.

Valid Usage

- The bits in `handleTypes` must be supported and compatible, as reported by VkExternalImageFormatProperties or VkExternalBufferProperties.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO`

- `handleTypes` must be a valid combination of VkExternalMemoryHandleTypeFlagBits values

To specify additional attributes of NT handles exported from a memory object, add a VkExportMemoryWin32HandleInfoKHR structure to the `pNext` chain of the VkMemoryAllocateInfo structure. The `VkExportMemoryWin32HandleInfoKHR` structure is defined as:

    typedef struct VkExportMemoryWin32HandleInfoKHR {
        VkStructureType               sType;
        const void*                   pNext;
        const SECURITY_ATTRIBUTES*    pAttributes;
        DWORD                         dwAccess;
        LPCWSTR                       name;
    } VkExportMemoryWin32HandleInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `pAttributes` is a pointer to a Windows `SECURITY_ATTRIBUTES` structure specifying security attributes of the handle.

- `dwAccess` is a `DWORD` specifying access rights of the handle.

- `name` is a null-terminated UTF-16 string to associate with the underlying resource referenced by NT handles exported from the created memory.

If VkExportMemoryAllocateInfo is not present in the same `pNext` chain, this structure is ignored.

If VkExportMemoryAllocateInfo is present in the `pNext` chain of VkMemoryAllocateInfo with a Windows `handleType`, but either `VkExportMemoryWin32HandleInfoKHR` is not present in the `pNext` chain, or if it is but `pAttributes` is set to `NULL`, default security descriptor values will be used, and child processes created by the application will not inherit the handle, as described in the MSDN documentation for “Synchronization Object Security and Access Rights”1. Further, if the structure is not present, the access rights used depend on the handle type.

For handles of the following types:

`VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT` `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_BIT`

The implementation must ensure the access rights allow read and write access to the memory.

For handles of the following types:

`VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_HEAP_BIT` `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_RESOURCE_BIT`

The access rights must be:

`GENERIC_ALL`

1

  https://docs.microsoft.com/en-us/windows/win32/sync/synchronization-object-security-and-access-rights

Valid Usage

- If VkExportMemoryAllocateInfo::`handleTypes` does not include `VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT`, `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_BIT`, `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_HEAP_BIT`, or `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_RESOURCE_BIT`, a `VkExportMemoryWin32HandleInfoKHR` structure must not be included in the `pNext` chain of VkMemoryAllocateInfo.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_EXPORT_MEMORY_WIN32_HANDLE_INFO_KHR`

- If `pAttributes` is not `NULL`, `pAttributes` must be a valid pointer to a valid `SECURITY_ATTRIBUTES` value

To import memory from a Windows handle, add a VkImportMemoryWin32HandleInfoKHR structure to the `pNext` chain of the VkMemoryAllocateInfo structure.

The `VkImportMemoryWin32HandleInfoKHR` structure is defined as:

    typedef struct VkImportMemoryWin32HandleInfoKHR {
        VkStructureType                       sType;
        const void*                           pNext;
        VkExternalMemoryHandleTypeFlagBits    handleType;
        HANDLE                                handle;
        LPCWSTR                               name;
    } VkImportMemoryWin32HandleInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `handleType` specifies the type of `handle` or `name`.

- `handle` is the external handle to import, or `NULL`.

- `name` is a null-terminated UTF-16 string naming the underlying memory resource to import, or `NULL`.

Importing memory objects from Windows handles does not transfer ownership of the handle to the Vulkan implementation. For handle types defined as NT handles, the application must release ownership using the `CloseHandle` system call when the handle is no longer needed.

Applications can import the same underlying memory into multiple instances of Vulkan, into the same instance from which it was exported, and multiple times into a given Vulkan instance. In all cases, each import operation must create a distinct `VkDeviceMemory` object.

Valid Usage

- If `handleType` is not `0`, it must be supported for import, as reported by VkExternalImageFormatProperties or VkExternalBufferProperties.

- The memory from which `handle` was exported, or the memory named by `name` must have been created on the same underlying physical device as `device`.

- If `handleType` is not `0`, it must be defined as an NT handle or a global share handle.

- If `handleType` is not `VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT`, `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_BIT`, `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_HEAP_BIT`, or `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_RESOURCE_BIT`, `name` must be `NULL`.

- If `handleType` is not `0` and `handle` is `NULL`, `name` must name a valid memory resource of the type specified by `handleType`.

- If `handleType` is not `0` and `name` is `NULL`, `handle` must be a valid handle of the type specified by `handleType`.

- if `handle` is not `NULL`, `name` must be `NULL`.

- If `handle` is not `NULL`, it must obey any requirements listed for `handleType` in external memory handle types compatibility.

- If `name` is not `NULL`, it must obey any requirements listed for `handleType` in external memory handle types compatibility.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMPORT_MEMORY_WIN32_HANDLE_INFO_KHR`

- If `handleType` is not `0`, `handleType` must be a valid VkExternalMemoryHandleTypeFlagBits value

To export a Windows handle representing the underlying resources of a Vulkan device memory object, call:

    VkResult vkGetMemoryWin32HandleKHR(
        VkDevice                                    device,
        const VkMemoryGetWin32HandleInfoKHR*        pGetWin32HandleInfo,
        HANDLE*                                     pHandle);

- `device` is the logical device that created the device memory being exported.

- `pGetWin32HandleInfo` is a pointer to a VkMemoryGetWin32HandleInfoKHR structure containing parameters of the export operation.

- `pHandle` will return the Windows handle representing the underlying resources of the device memory object.

For handle types defined as NT handles, the handles returned by `vkGetMemoryWin32HandleKHR` are owned by the application. To avoid leaking resources, the application must release ownership of them using the `CloseHandle` system call when they are no longer needed.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pGetWin32HandleInfo` must be a valid pointer to a valid VkMemoryGetWin32HandleInfoKHR structure

- `pHandle` must be a valid pointer to a `HANDLE` value

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_TOO_MANY_OBJECTS`

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

The `VkMemoryGetWin32HandleInfoKHR` structure is defined as:

    typedef struct VkMemoryGetWin32HandleInfoKHR {
        VkStructureType                       sType;
        const void*                           pNext;
        VkDeviceMemory                        memory;
        VkExternalMemoryHandleTypeFlagBits    handleType;
    } VkMemoryGetWin32HandleInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `memory` is the memory object from which the handle will be exported.

- `handleType` is the type of handle requested.

The properties of the handle returned depend on the value of `handleType`. See VkExternalMemoryHandleTypeFlagBits for a description of the properties of the defined external memory handle types.

Valid Usage

- `handleType` must have been included in VkExportMemoryAllocateInfo::`handleTypes` when `memory` was created.

- If `handleType` is defined as an NT handle, vkGetMemoryWin32HandleKHR must be called no more than once for each valid unique combination of `memory` and `handleType`.

- `handleType` must be defined as an NT handle or a global share handle.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_MEMORY_GET_WIN32_HANDLE_INFO_KHR`

- `pNext` must be `NULL`

- `memory` must be a valid VkDeviceMemory handle

- `handleType` must be a valid VkExternalMemoryHandleTypeFlagBits value

Windows memory handles compatible with Vulkan may also be created by non-Vulkan APIs using methods beyond the scope of this specification. To determine the correct parameters to use when importing such handles, call:

    VkResult vkGetMemoryWin32HandlePropertiesKHR(
        VkDevice                                    device,
        VkExternalMemoryHandleTypeFlagBits          handleType,
        HANDLE                                      handle,
        VkMemoryWin32HandlePropertiesKHR*           pMemoryWin32HandleProperties);

- `device` is the logical device that will be importing `handle`.

- `handleType` is the type of the handle `handle`.

- `handle` is the handle which will be imported.

- `pMemoryWin32HandleProperties` will return properties of `handle`.

Valid Usage

- `handle` must be an external memory handle created outside of the Vulkan API.

- `handleType` must not be one of the handle types defined as opaque.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `handleType` must be a valid VkExternalMemoryHandleTypeFlagBits value

- `pMemoryWin32HandleProperties` must be a valid pointer to a VkMemoryWin32HandlePropertiesKHR structure

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_INVALID_EXTERNAL_HANDLE`

The `VkMemoryWin32HandlePropertiesKHR` structure returned is defined as:

    typedef struct VkMemoryWin32HandlePropertiesKHR {
        VkStructureType    sType;
        void*              pNext;
        uint32_t           memoryTypeBits;
    } VkMemoryWin32HandlePropertiesKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `memoryTypeBits` is a bitmask containing one bit set for every memory type which the specified windows handle can be imported as.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_MEMORY_WIN32_HANDLE_PROPERTIES_KHR`

- `pNext` must be `NULL`

To import memory from a POSIX file descriptor handle, add a VkImportMemoryFdInfoKHR structure to the `pNext` chain of the VkMemoryAllocateInfo structure. The `VkImportMemoryFdInfoKHR` structure is defined as:

    typedef struct VkImportMemoryFdInfoKHR {
        VkStructureType                       sType;
        const void*                           pNext;
        VkExternalMemoryHandleTypeFlagBits    handleType;
        int                                   fd;
    } VkImportMemoryFdInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `handleType` specifies the handle type of `fd`.

- `fd` is the external handle to import.

Importing memory from a file descriptor transfers ownership of the file descriptor from the application to the Vulkan implementation. The application must not perform any operations on the file descriptor after a successful import.

Applications can import the same underlying memory into multiple instances of Vulkan, into the same instance from which it was exported, and multiple times into a given Vulkan instance. In all cases, each import operation must create a distinct `VkDeviceMemory` object.

Valid Usage

- If `handleType` is not `0`, it must be supported for import, as reported by VkExternalImageFormatProperties or VkExternalBufferProperties.

- The memory from which `fd` was exported must have been created on the same underlying physical device as `device`.

- If `handleType` is not `0`, it must be defined as a POSIX file descriptor handle.

- If `handleType` is not `0`, `fd` must be a valid handle of the type specified by `handleType`.

- The memory represented by `fd` must have been created from a physical device and driver that is compatible with `device` and `handleType`, as described in External memory handle types compatibility.

- `fd` must obey any requirements listed for `handleType` in external memory handle types compatibility.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMPORT_MEMORY_FD_INFO_KHR`

- If `handleType` is not `0`, `handleType` must be a valid VkExternalMemoryHandleTypeFlagBits value

To export a POSIX file descriptor representing the underlying resources of a Vulkan device memory object, call:

    VkResult vkGetMemoryFdKHR(
        VkDevice                                    device,
        const VkMemoryGetFdInfoKHR*                 pGetFdInfo,
        int*                                        pFd);

- `device` is the logical device that created the device memory being exported.

- `pGetFdInfo` is a pointer to a VkMemoryGetFdInfoKHR structure containing parameters of the export operation.

- `pFd` will return a file descriptor representing the underlying resources of the device memory object.

Each call to `vkGetMemoryFdKHR` must create a new file descriptor and transfer ownership of it to the application. To avoid leaking resources, the application must release ownership of the file descriptor using the `close` system call when it is no longer needed, or by importing a Vulkan memory object from it. Where supported by the operating system, the implementation must set the file descriptor to be closed automatically when an `execve` system call is made.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pGetFdInfo` must be a valid pointer to a valid VkMemoryGetFdInfoKHR structure

- `pFd` must be a valid pointer to an `int` value

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_TOO_MANY_OBJECTS`

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

The `VkMemoryGetFdInfoKHR` structure is defined as:

    typedef struct VkMemoryGetFdInfoKHR {
        VkStructureType                       sType;
        const void*                           pNext;
        VkDeviceMemory                        memory;
        VkExternalMemoryHandleTypeFlagBits    handleType;
    } VkMemoryGetFdInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `memory` is the memory object from which the handle will be exported.

- `handleType` is the type of handle requested.

The properties of the file descriptor exported depend on the value of `handleType`. See VkExternalMemoryHandleTypeFlagBits for a description of the properties of the defined external memory handle types.

| Note The size of the exported file may be larger than the size requested by VkMemoryAllocateInfo::allocationSize. If `handleType` is `VK_EXTERNAL_MEMORY_HANDLE_TYPE_DMA_BUF_BIT_EXT`, then the application can query the file’s actual size with lseek(2).

Valid Usage

- `handleType` must have been included in VkExportMemoryAllocateInfo::`handleTypes` when `memory` was created.

- `handleType` must be defined as a POSIX file descriptor handle.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_MEMORY_GET_FD_INFO_KHR`

- `pNext` must be `NULL`

- `memory` must be a valid VkDeviceMemory handle

- `handleType` must be a valid VkExternalMemoryHandleTypeFlagBits value

POSIX file descriptor memory handles compatible with Vulkan may also be created by non-Vulkan APIs using methods beyond the scope of this specification. To determine the correct parameters to use when importing such handles, call:

    VkResult vkGetMemoryFdPropertiesKHR(
        VkDevice                                    device,
        VkExternalMemoryHandleTypeFlagBits          handleType,
        int                                         fd,
        VkMemoryFdPropertiesKHR*                    pMemoryFdProperties);

- `device` is the logical device that will be importing `fd`.

- `handleType` is the type of the handle `fd`.

- `fd` is the handle which will be imported.

- `pMemoryFdProperties` is a pointer to a VkMemoryFdPropertiesKHR structure in which the properties of the handle `fd` are returned.

Valid Usage

- `fd` must be an external memory handle created outside of the Vulkan API.

- `handleType` must not be `VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_FD_BIT_KHR`.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `handleType` must be a valid VkExternalMemoryHandleTypeFlagBits value

- `pMemoryFdProperties` must be a valid pointer to a VkMemoryFdPropertiesKHR structure

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_INVALID_EXTERNAL_HANDLE`

The `VkMemoryFdPropertiesKHR` structure returned is defined as:

    typedef struct VkMemoryFdPropertiesKHR {
        VkStructureType    sType;
        void*              pNext;
        uint32_t           memoryTypeBits;
    } VkMemoryFdPropertiesKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `memoryTypeBits` is a bitmask containing one bit set for every memory type which the specified file descriptor can be imported as.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_MEMORY_FD_PROPERTIES_KHR`

- `pNext` must be `NULL`

To import memory from a host pointer, add a VkImportMemoryHostPointerInfoEXT structure to the `pNext` chain of the VkMemoryAllocateInfo structure. The `VkImportMemoryHostPointerInfoEXT` structure is defined as:

    typedef struct VkImportMemoryHostPointerInfoEXT {
        VkStructureType                       sType;
        const void*                           pNext;
        VkExternalMemoryHandleTypeFlagBits    handleType;
        void*                                 pHostPointer;
    } VkImportMemoryHostPointerInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `handleType` specifies the handle type.

- `pHostPointer` is the host pointer to import from.

Importing memory from a host pointer shares ownership of the memory between the host and the Vulkan implementation. The application can continue to access the memory through the host pointer but it is the application’s responsibility to synchronize device and non-device access to the underlying memory as defined in Host Access to Device Memory Objects.

Applications can import the same underlying memory into multiple instances of Vulkan and multiple times into a given Vulkan instance. However, implementations may fail to import the same underlying memory multiple times into a given physical device due to platform constraints.

Importing memory from a particular host pointer may not be possible due to additional platform-specific restrictions beyond the scope of this specification in which case the implementation must fail the memory import operation with the error code `VK_ERROR_INVALID_EXTERNAL_HANDLE_KHR`.

The application must ensure that the imported memory range remains valid and accessible for the lifetime of the imported memory object.

Valid Usage

- If `handleType` is not `0`, it must be supported for import, as reported in VkExternalMemoryProperties

- If `handleType` is not `0`, it must be `VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_ALLOCATION_BIT_EXT` or `VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_MAPPED_FOREIGN_MEMORY_BIT_EXT`

- `pHostPointer` must be a pointer aligned to an integer multiple of `VkPhysicalDeviceExternalMemoryHostPropertiesEXT`::`minImportedHostPointerAlignment`

- If `handleType` is `VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_ALLOCATION_BIT_EXT`, `pHostPointer` must be a pointer to `allocationSize` number of bytes of host memory, where `allocationSize` is the member of the `VkMemoryAllocateInfo` structure this structure is chained to

- If `handleType` is `VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_MAPPED_FOREIGN_MEMORY_BIT_EXT`, `pHostPointer` must be a pointer to `allocationSize` number of bytes of host mapped foreign memory, where `allocationSize` is the member of the `VkMemoryAllocateInfo` structure this structure is chained to

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMPORT_MEMORY_HOST_POINTER_INFO_EXT`

- `handleType` must be a valid VkExternalMemoryHandleTypeFlagBits value

To determine the correct parameters to use when importing host pointers, call:

    VkResult vkGetMemoryHostPointerPropertiesEXT(
        VkDevice                                    device,
        VkExternalMemoryHandleTypeFlagBits          handleType,
        const void*                                 pHostPointer,
        VkMemoryHostPointerPropertiesEXT*           pMemoryHostPointerProperties);

- `device` is the logical device that will be importing `pHostPointer`.

- `handleType` is the type of the handle `pHostPointer`.

- `pHostPointer` is the host pointer to import from.

- `pMemoryHostPointerProperties` is a pointer to a VkMemoryHostPointerPropertiesEXT structure in which the host pointer properties are returned.

Valid Usage

- `handleType` must be `VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_ALLOCATION_BIT_EXT` or `VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_MAPPED_FOREIGN_MEMORY_BIT_EXT`

- `pHostPointer` must be a pointer aligned to an integer multiple of `VkPhysicalDeviceExternalMemoryHostPropertiesEXT`::`minImportedHostPointerAlignment`

- If `handleType` is `VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_ALLOCATION_BIT_EXT`, `pHostPointer` must be a pointer to host memory

- If `handleType` is `VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_MAPPED_FOREIGN_MEMORY_BIT_EXT`, `pHostPointer` must be a pointer to host mapped foreign memory

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `handleType` must be a valid VkExternalMemoryHandleTypeFlagBits value

- `pMemoryHostPointerProperties` must be a valid pointer to a VkMemoryHostPointerPropertiesEXT structure

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_INVALID_EXTERNAL_HANDLE`

The `VkMemoryHostPointerPropertiesEXT` structure is defined as:

    typedef struct VkMemoryHostPointerPropertiesEXT {
        VkStructureType    sType;
        void*              pNext;
        uint32_t           memoryTypeBits;
    } VkMemoryHostPointerPropertiesEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `memoryTypeBits` is a bitmask containing one bit set for every memory type which the specified host pointer can be imported as.

The value returned by `memoryTypeBits` must only include bits that identify memory types which are host visible.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_MEMORY_HOST_POINTER_PROPERTIES_EXT`

- `pNext` must be `NULL`

To import memory created outside of the current Vulkan instance from an Android hardware buffer, add a `VkImportAndroidHardwareBufferInfoANDROID` structure to the `pNext` chain of the VkMemoryAllocateInfo structure. The `VkImportAndroidHardwareBufferInfoANDROID` structure is defined as:

    typedef struct VkImportAndroidHardwareBufferInfoANDROID {
        VkStructureType            sType;
        const void*                pNext;
        struct AHardwareBuffer*    buffer;
    } VkImportAndroidHardwareBufferInfoANDROID;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `buffer` is the Android hardware buffer to import.

If the vkAllocateMemory command succeeds, the implementation must acquire a reference to the imported hardware buffer, which it must release when the device memory object is freed. If the command fails, the implementation must not retain a reference.

Valid Usage

- If `buffer` is not `NULL`, Android hardware buffers must be supported for import, as reported by VkExternalImageFormatProperties or VkExternalBufferProperties.

- If `buffer` is not `NULL`, it must be a valid Android hardware buffer object with `AHardwareBuffer_Desc`::`format` and `AHardwareBuffer_Desc`::`usage` compatible with Vulkan as described in Android Hardware Buffers.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMPORT_ANDROID_HARDWARE_BUFFER_INFO_ANDROID`

- `buffer` must be a valid pointer to an `AHardwareBuffer` value

To export an Android hardware buffer representing the underlying resources of a Vulkan device memory object, call:

    VkResult vkGetMemoryAndroidHardwareBufferANDROID(
        VkDevice                                    device,
        const VkMemoryGetAndroidHardwareBufferInfoANDROID* pInfo,
        struct AHardwareBuffer**                    pBuffer);

- `device` is the logical device that created the device memory being exported.

- `pInfo` is a pointer to a VkMemoryGetAndroidHardwareBufferInfoANDROID structure containing parameters of the export operation.

- `pBuffer` will return an Android hardware buffer representing the underlying resources of the device memory object.

Each call to `vkGetMemoryAndroidHardwareBufferANDROID` must return an Android hardware buffer with a new reference acquired in addition to the reference held by the VkDeviceMemory. To avoid leaking resources, the application must release the reference by calling `AHardwareBuffer_release` when it is no longer needed. When called with the same handle in VkMemoryGetAndroidHardwareBufferInfoANDROID::`memory`, `vkGetMemoryAndroidHardwareBufferANDROID` must return the same Android hardware buffer object. If the device memory was created by importing an Android hardware buffer, `vkGetMemoryAndroidHardwareBufferANDROID` must return that same Android hardware buffer object.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pInfo` must be a valid pointer to a valid VkMemoryGetAndroidHardwareBufferInfoANDROID structure

- `pBuffer` must be a valid pointer to a valid pointer to an `AHardwareBuffer` value

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_TOO_MANY_OBJECTS`

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

The `VkMemoryGetAndroidHardwareBufferInfoANDROID` structure is defined as:

    typedef struct VkMemoryGetAndroidHardwareBufferInfoANDROID {
        VkStructureType    sType;
        const void*        pNext;
        VkDeviceMemory     memory;
    } VkMemoryGetAndroidHardwareBufferInfoANDROID;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `memory` is the memory object from which the Android hardware buffer will be exported.

Valid Usage

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID` must have been included in VkExportMemoryAllocateInfo::`handleTypes` when `memory` was created.

- If the `pNext` chain of the VkMemoryAllocateInfo used to allocate `memory` included a VkMemoryDedicatedAllocateInfo with non-`NULL` `image` member, then that `image` must already be bound to `memory`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_MEMORY_GET_ANDROID_HARDWARE_BUFFER_INFO_ANDROID`

- `pNext` must be `NULL`

- `memory` must be a valid VkDeviceMemory handle

To determine the memory parameters to use when importing an Android hardware buffer, call:

    VkResult vkGetAndroidHardwareBufferPropertiesANDROID(
        VkDevice                                    device,
        const struct AHardwareBuffer*               buffer,
        VkAndroidHardwareBufferPropertiesANDROID*   pProperties);

- `device` is the logical device that will be importing `buffer`.

- `buffer` is the Android hardware buffer which will be imported.

- `pProperties` is a pointer to a VkAndroidHardwareBufferPropertiesANDROID structure in which the properties of `buffer` are returned.

Valid Usage

- `buffer` must be a valid Android hardware buffer object with at least one of the `AHARDWAREBUFFER_USAGE_GPU_`* flags in its `AHardwareBuffer_Desc`::`usage`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `buffer` must be a valid pointer to a valid `AHardwareBuffer` value

- `pProperties` must be a valid pointer to a VkAndroidHardwareBufferPropertiesANDROID structure

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_INVALID_EXTERNAL_HANDLE_KHR`

The `VkAndroidHardwareBufferPropertiesANDROID` structure returned is defined as:

    typedef struct VkAndroidHardwareBufferPropertiesANDROID {
        VkStructureType    sType;
        void*              pNext;
        VkDeviceSize       allocationSize;
        uint32_t           memoryTypeBits;
    } VkAndroidHardwareBufferPropertiesANDROID;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `allocationSize` is the size of the external memory

- `memoryTypeBits` is a bitmask containing one bit set for every memory type which the specified Android hardware buffer can be imported as.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_ANDROID_HARDWARE_BUFFER_PROPERTIES_ANDROID`

- `pNext` must be `NULL` or a pointer to a valid instance of VkAndroidHardwareBufferFormatPropertiesANDROID

- The `sType` value of each struct in the `pNext` chain must be unique

To obtain format properties of an Android hardware buffer, include a `VkAndroidHardwareBufferFormatPropertiesANDROID` structure in the `pNext` chain of the VkAndroidHardwareBufferPropertiesANDROID structure passed to vkGetAndroidHardwareBufferPropertiesANDROID. This structure is defined as:

    typedef struct VkAndroidHardwareBufferFormatPropertiesANDROID {
        VkStructureType                  sType;
        void*                            pNext;
        VkFormat                         format;
        uint64_t                         externalFormat;
        VkFormatFeatureFlags             formatFeatures;
        VkComponentMapping               samplerYcbcrConversionComponents;
        VkSamplerYcbcrModelConversion    suggestedYcbcrModel;
        VkSamplerYcbcrRange              suggestedYcbcrRange;
        VkChromaLocation                 suggestedXChromaOffset;
        VkChromaLocation                 suggestedYChromaOffset;
    } VkAndroidHardwareBufferFormatPropertiesANDROID;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `format` is the Vulkan format corresponding to the Android hardware buffer’s format, or `VK_FORMAT_UNDEFINED` if there is not an equivalent Vulkan format.

- `externalFormat` is an implementation-defined external format identifier for use with VkExternalFormatANDROID. It must not be zero.

- `formatFeatures` describes the capabilities of this external format when used with an image bound to memory imported from `buffer`.

- `samplerYcbcrConversionComponents` is the component swizzle that should be used in VkSamplerYcbcrConversionCreateInfo.

- `suggestedYcbcrModel` is a suggested color model to use in the VkSamplerYcbcrConversionCreateInfo.

- `suggestedYcbcrRange` is a suggested numerical value range to use in VkSamplerYcbcrConversionCreateInfo.

- `suggestedXChromaOffset` is a suggested X chroma offset to use in VkSamplerYcbcrConversionCreateInfo.

- `suggestedYChromaOffset` is a suggested Y chroma offset to use in VkSamplerYcbcrConversionCreateInfo.

If the Android hardware buffer has one of the formats listed in the Format Equivalence table, then `format` must have the equivalent Vulkan format listed in the table. Otherwise, `format` may be `VK_FORMAT_UNDEFINED`, indicating the Android hardware buffer can only be used with an external format.

The `formatFeatures` member must include `VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT` and at least one of `VK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BIT` or `VK_FORMAT_FEATURE_COSITED_CHROMA_SAMPLES_BIT`, and should include `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT` and `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_LINEAR_FILTER_BIT`.

| Note The `formatFeatures` member only indicates the features available when using an external-format image created from the Android hardware buffer. Images from Android hardware buffers with a format other than `VK_FORMAT_UNDEFINED` are subject to the format capabilities obtained from vkGetPhysicalDeviceFormatProperties2, and vkGetPhysicalDeviceImageFormatProperties2 with appropriate parameters. These sets of features are independent of each other, e.g. the external format will support sampler Y′CBCR conversion even if the non-external format does not, and writing to non-external format images is possible but writing to external format images is not.

Android hardware buffers with the same external format must have the same support for `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT`, `VK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BIT`, `VK_FORMAT_FEATURE_COSITED_CHROMA_SAMPLES_BIT`, `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_LINEAR_FILTER_BIT`, `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_SEPARATE_RECONSTRUCTION_FILTER_BIT`, and `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_FORCEABLE_BIT`. in `formatFeatures`. Other format features may differ between Android hardware buffers that have the same external format. This allows applications to use the same VkSamplerYcbcrConversion object (and samplers and pipelines created from them) for any Android hardware buffers that have the same external format.

If `format` is not `VK_FORMAT_UNDEFINED`, then the value of `samplerYcbcrConversionComponents` must be valid when used as the `components` member of VkSamplerYcbcrConversionCreateInfo with that format. If `format` is `VK_FORMAT_UNDEFINED`, all members of `samplerYcbcrConversionComponents` must be `VK_COMPONENT_SWIZZLE_IDENTITY`.

Implementations may not always be able to determine the color model, numerical range, or chroma offsets of the image contents, so the values in `VkAndroidHardwareBufferFormatPropertiesANDROID` are only suggestions. Applications should treat these values as sensible defaults to use in the absence of more reliable information obtained through some other means. If the underlying physical device is also usable via OpenGL ES with the `GL_OES_EGL_image_external` extension, the implementation should suggest values that will produce similar sampled values as would be obtained by sampling the same external image via `samplerExternalOES` in OpenGL ES using equivalent sampler parameters.

| Note Since `GL_OES_EGL_image_external` does not require the same sampling and conversion calculations as Vulkan does, achieving identical results between APIs may not be possible on some implementations.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_ANDROID_HARDWARE_BUFFER_FORMAT_PROPERTIES_ANDROID`

When allocating memory that may be exported to another process or Vulkan instance, add a VkExportMemoryAllocateInfoNV structure to the `pNext` chain of the VkMemoryAllocateInfo structure, specifying the handle types that may be exported.

The VkExportMemoryAllocateInfoNV structure is defined as:

    typedef struct VkExportMemoryAllocateInfoNV {
        VkStructureType                      sType;
        const void*                          pNext;
        VkExternalMemoryHandleTypeFlagsNV    handleTypes;
    } VkExportMemoryAllocateInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `handleTypes` is a bitmask of VkExternalMemoryHandleTypeFlagBitsNV specifying one or more memory handle types that may be exported. Multiple handle types may be requested for the same allocation as long as they are compatible, as reported by vkGetPhysicalDeviceExternalImageFormatPropertiesNV.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO_NV`

- `handleTypes` must be a valid combination of VkExternalMemoryHandleTypeFlagBitsNV values

When VkExportMemoryAllocateInfoNV::`handleTypes` includes `VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT_NV`, add a `VkExportMemoryWin32HandleInfoNV` structure to the `pNext` chain of the VkExportMemoryAllocateInfoNV structure to specify security attributes and access rights for the memory object’s external handle.

The `VkExportMemoryWin32HandleInfoNV` structure is defined as:

    typedef struct VkExportMemoryWin32HandleInfoNV {
        VkStructureType               sType;
        const void*                   pNext;
        const SECURITY_ATTRIBUTES*    pAttributes;
        DWORD                         dwAccess;
    } VkExportMemoryWin32HandleInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `pAttributes` is a pointer to a Windows `SECURITY_ATTRIBUTES` structure specifying security attributes of the handle.

- `dwAccess` is a `DWORD` specifying access rights of the handle.

If this structure is not present, or if `pAttributes` is set to `NULL`, default security descriptor values will be used, and child processes created by the application will not inherit the handle, as described in the MSDN documentation for “Synchronization Object Security and Access Rights”1. Further, if the structure is not present, the access rights will be

`DXGI_SHARED_RESOURCE_READ` | `DXGI_SHARED_RESOURCE_WRITE`

1

  https://docs.microsoft.com/en-us/windows/win32/sync/synchronization-object-security-and-access-rights

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_EXPORT_MEMORY_WIN32_HANDLE_INFO_NV`

- If `pAttributes` is not `NULL`, `pAttributes` must be a valid pointer to a valid `SECURITY_ATTRIBUTES` value

To import memory created on the same physical device but outside of the current Vulkan instance, add a VkImportMemoryWin32HandleInfoNV structure to the `pNext` chain of the VkMemoryAllocateInfo structure, specifying a handle to and the type of the memory.

The `VkImportMemoryWin32HandleInfoNV` structure is defined as:

    typedef struct VkImportMemoryWin32HandleInfoNV {
        VkStructureType                      sType;
        const void*                          pNext;
        VkExternalMemoryHandleTypeFlagsNV    handleType;
        HANDLE                               handle;
    } VkImportMemoryWin32HandleInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `handleType` is `0` or a VkExternalMemoryHandleTypeFlagBitsNV value specifying the type of memory handle in `handle`.

- `handle` is a Windows `HANDLE` referring to the memory.

If `handleType` is `0`, this structure is ignored by consumers of the VkMemoryAllocateInfo structure it is chained from.

Valid Usage

- `handleType` must not have more than one bit set.

- `handle` must be a valid handle to memory, obtained as specified by `handleType`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMPORT_MEMORY_WIN32_HANDLE_INFO_NV`

- `handleType` must be a valid combination of VkExternalMemoryHandleTypeFlagBitsNV values

Bits which can be set in `handleType` are:

Possible values of VkImportMemoryWin32HandleInfoNV::`handleType`, specifying the type of an external memory handle, are:

    typedef enum VkExternalMemoryHandleTypeFlagBitsNV {
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT_NV = 0x00000001,
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT_NV = 0x00000002,
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_IMAGE_BIT_NV = 0x00000004,
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_IMAGE_KMT_BIT_NV = 0x00000008,
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_FLAG_BITS_MAX_ENUM_NV = 0x7FFFFFFF
    } VkExternalMemoryHandleTypeFlagBitsNV;

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT_NV` specifies a handle to memory returned by vkGetMemoryWin32HandleNV.

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT_NV` specifies a handle to memory returned by vkGetMemoryWin32HandleNV, or one duplicated from such a handle using `DuplicateHandle()`.

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_IMAGE_BIT_NV` specifies a valid NT handle to memory returned by `IDXGIResource1::CreateSharedHandle`, or a handle duplicated from such a handle using `DuplicateHandle()`.

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_IMAGE_KMT_BIT_NV` specifies a handle to memory returned by `IDXGIResource::GetSharedHandle()`.

| editing-note (Jon) If additional (non-Win32) bits are added to the possible memory types, this type should move to the `VK_NV_external_memory_capabilities` section, and each bit would then be protected by ifdefs for the extension it’s defined by.

    typedef VkFlags VkExternalMemoryHandleTypeFlagsNV;

`VkExternalMemoryHandleTypeFlagsNV` is a bitmask type for setting a mask of zero or more VkExternalMemoryHandleTypeFlagBitsNV.

To retrieve the handle corresponding to a device memory object created with VkExportMemoryAllocateInfoNV::`handleTypes` set to include `VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT_NV` or `VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT_NV`, call:

    VkResult vkGetMemoryWin32HandleNV(
        VkDevice                                    device,
        VkDeviceMemory                              memory,
        VkExternalMemoryHandleTypeFlagsNV           handleType,
        HANDLE*                                     pHandle);

- `device` is the logical device that owns the memory.

- `memory` is the VkDeviceMemory object.

- `handleType` is a bitmask of VkExternalMemoryHandleTypeFlagBitsNV containing a single bit specifying the type of handle requested.

- `handle` is a pointer to a Windows `HANDLE` in which the handle is returned.

Valid Usage

- `handleType` must be a flag specified in VkExportMemoryAllocateInfoNV::`handleTypes` when allocating `memory`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `memory` must be a valid VkDeviceMemory handle

- `handleType` must be a valid combination of VkExternalMemoryHandleTypeFlagBitsNV values

- `handleType` must not be `0`

- `pHandle` must be a valid pointer to a `HANDLE` value

- `memory` must have been created, allocated, or retrieved from `device`

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_TOO_MANY_OBJECTS`

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

If the `pNext` chain of VkMemoryAllocateInfo includes a `VkMemoryAllocateFlagsInfo` structure, then that structure includes flags and a device mask controlling how many instances of the memory will be allocated.

The `VkMemoryAllocateFlagsInfo` structure is defined as:

    typedef struct VkMemoryAllocateFlagsInfo {
        VkStructureType          sType;
        const void*              pNext;
        VkMemoryAllocateFlags    flags;
        uint32_t                 deviceMask;
    } VkMemoryAllocateFlagsInfo;

or the equivalent

    typedef VkMemoryAllocateFlagsInfo VkMemoryAllocateFlagsInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkMemoryAllocateFlagBits controlling the allocation.

- `deviceMask` is a mask of physical devices in the logical device, indicating that memory must be allocated on each device in the mask, if `VK_MEMORY_ALLOCATE_DEVICE_MASK_BIT` is set in `flags`.

If `VK_MEMORY_ALLOCATE_DEVICE_MASK_BIT` is not set, the number of instances allocated depends on whether `VK_MEMORY_HEAP_MULTI_INSTANCE_BIT` is set in the memory heap. If `VK_MEMORY_HEAP_MULTI_INSTANCE_BIT` is set, then memory is allocated for every physical device in the logical device (as if `deviceMask` has bits set for all device indices). If `VK_MEMORY_HEAP_MULTI_INSTANCE_BIT` is not set, then a single instance of memory is allocated (as if `deviceMask` is set to one).

On some implementations, allocations from a multi-instance heap may consume memory on all physical devices even if the `deviceMask` excludes some devices. If VkPhysicalDeviceGroupProperties::`subsetAllocation` is `VK_TRUE`, then memory is only consumed for the devices in the device mask.

| Note In practice, most allocations on a multi-instance heap will be allocated across all physical devices. Unicast allocation support is an optional optimization for a minority of allocations.

Valid Usage

- If `VK_MEMORY_ALLOCATE_DEVICE_MASK_BIT` is set, `deviceMask` must be a valid device mask.

- If `VK_MEMORY_ALLOCATE_DEVICE_MASK_BIT` is set, `deviceMask` must not be zero

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_FLAGS_INFO`

- `flags` must be a valid combination of VkMemoryAllocateFlagBits values

Bits which can be set in VkMemoryAllocateFlagsInfo::`flags`, controlling device memory allocation, are:

    typedef enum VkMemoryAllocateFlagBits {
        VK_MEMORY_ALLOCATE_DEVICE_MASK_BIT = 0x00000001,
        VK_MEMORY_ALLOCATE_DEVICE_ADDRESS_BIT = 0x00000002,
        VK_MEMORY_ALLOCATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT = 0x00000004,
        VK_MEMORY_ALLOCATE_DEVICE_MASK_BIT_KHR = VK_MEMORY_ALLOCATE_DEVICE_MASK_BIT,
        VK_MEMORY_ALLOCATE_DEVICE_ADDRESS_BIT_KHR = VK_MEMORY_ALLOCATE_DEVICE_ADDRESS_BIT,
        VK_MEMORY_ALLOCATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT_KHR = VK_MEMORY_ALLOCATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT,
        VK_MEMORY_ALLOCATE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkMemoryAllocateFlagBits;

or the equivalent

    typedef VkMemoryAllocateFlagBits VkMemoryAllocateFlagBitsKHR;

- `VK_MEMORY_ALLOCATE_DEVICE_MASK_BIT` specifies that memory will be allocated for the devices in VkMemoryAllocateFlagsInfo::`deviceMask`.

- `VK_MEMORY_ALLOCATE_DEVICE_ADDRESS_BIT` specifies that the memory can be attached to a buffer object created with the `VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT` bit set in `usage`, and that the memory handle can be used to retrieve an opaque address via vkGetDeviceMemoryOpaqueCaptureAddress.

- `VK_MEMORY_ALLOCATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT` specifies that the memory’s address can be saved and reused on a subsequent run (e.g. for trace capture and replay), see VkBufferOpaqueCaptureAddressCreateInfo for more detail.

    typedef VkFlags VkMemoryAllocateFlags;

or the equivalent

    typedef VkMemoryAllocateFlags VkMemoryAllocateFlagsKHR;

`VkMemoryAllocateFlags` is a bitmask type for setting a mask of zero or more VkMemoryAllocateFlagBits.

To request a specific device address for a memory allocation, add a VkMemoryOpaqueCaptureAddressAllocateInfo structure to the `pNext` chain of the VkMemoryAllocateInfo structure. The `VkMemoryOpaqueCaptureAddressAllocateInfo` structure is defined as:

    typedef struct VkMemoryOpaqueCaptureAddressAllocateInfo {
        VkStructureType    sType;
        const void*        pNext;
        uint64_t           opaqueCaptureAddress;
    } VkMemoryOpaqueCaptureAddressAllocateInfo;

or the equivalent

    typedef VkMemoryOpaqueCaptureAddressAllocateInfo VkMemoryOpaqueCaptureAddressAllocateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `opaqueCaptureAddress` is the opaque capture address requested for the memory allocation.

If `opaqueCaptureAddress` is zero, no specific address is requested.

If `opaqueCaptureAddress` is not zero, it should be an address retrieved from vkGetDeviceMemoryOpaqueCaptureAddress on an identically created memory allocation on the same implementation.

| Note In most cases, it is expected that a non-zero `opaqueAddress` is an address retrieved from vkGetDeviceMemoryOpaqueCaptureAddress on an identically created memory allocation. If this is not the case, it likely that `VK_ERROR_INVALID_OPAQUE_CAPTURE_ADDRESS` errors will occur. This is, however, not a strict requirement because trace capture/replay tools may need to adjust memory allocation parameters for imported memory.

If this structure is not present, it is as if `opaqueCaptureAddress` is zero.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_MEMORY_OPAQUE_CAPTURE_ADDRESS_ALLOCATE_INFO`

To free a memory object, call:

    void vkFreeMemory(
        VkDevice                                    device,
        VkDeviceMemory                              memory,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that owns the memory.

- `memory` is the VkDeviceMemory object to be freed.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Before freeing a memory object, an application must ensure the memory object is no longer in use by the device—​for example by command buffers in the pending state. Memory can be freed whilst still bound to resources, but those resources must not be used afterwards. If there are still any bound images or buffers, the memory may not be immediately released by the implementation, but must be released by the time all bound images and buffers have been destroyed. Once memory is released, it is returned to the heap from which it was allocated.

How memory objects are bound to Images and Buffers is described in detail in the Resource Memory Association section.

If a memory object is mapped at the time it is freed, it is implicitly unmapped.

| Note As described below, host writes are not implicitly flushed when the memory object is unmapped, but the implementation must guarantee that writes that have not been flushed do not affect any other memory.

Valid Usage

- All submitted commands that refer to `memory` (via images or buffers) must have completed execution

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `memory` is not VK_NULL_HANDLE, `memory` must be a valid VkDeviceMemory handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- If `memory` is a valid handle, it must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `memory` must be externally synchronized

#### 10.2.1. Host Access to Device Memory Objects

Memory objects created with vkAllocateMemory are not directly host accessible.

Memory objects created with the memory property `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` are considered mappable. Memory objects must be mappable in order to be successfully mapped on the host.

To retrieve a host virtual address pointer to a region of a mappable memory object, call:

    VkResult vkMapMemory(
        VkDevice                                    device,
        VkDeviceMemory                              memory,
        VkDeviceSize                                offset,
        VkDeviceSize                                size,
        VkMemoryMapFlags                            flags,
        void**                                      ppData);

- `device` is the logical device that owns the memory.

- `memory` is the VkDeviceMemory object to be mapped.

- `offset` is a zero-based byte offset from the beginning of the memory object.

- `size` is the size of the memory range to map, or `VK_WHOLE_SIZE` to map from `offset` to the end of the allocation.

- `flags` is reserved for future use.

- `ppData` is a pointer to a `void *` variable in which is returned a host-accessible pointer to the beginning of the mapped range. This pointer minus `offset` must be aligned to at least VkPhysicalDeviceLimits::`minMemoryMapAlignment`.

After a successful call to `vkMapMemory` the memory object `memory` is considered to be currently host mapped.

| Note It is an application error to call `vkMapMemory` on a memory object that is already host mapped.

| Note `vkMapMemory` will fail if the implementation is unable to allocate an appropriately sized contiguous virtual address range, e.g. due to virtual address space fragmentation or platform limits. In such cases, `vkMapMemory` must return `VK_ERROR_MEMORY_MAP_FAILED`. The application can improve the likelihood of success by reducing the size of the mapped range and/or removing unneeded mappings using vkUnmapMemory.

`vkMapMemory` does not check whether the device memory is currently in use before returning the host-accessible pointer. The application must guarantee that any previously submitted command that writes to this range has completed before the host reads from or writes to that range, and that any previously submitted command that reads from that range has completed before the host writes to that region (see here for details on fulfilling such a guarantee). If the device memory was allocated without the `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT` set, these guarantees must be made for an extended range: the application must round down the start of the range to the nearest multiple of VkPhysicalDeviceLimits::`nonCoherentAtomSize`, and round the end of the range up to the nearest multiple of VkPhysicalDeviceLimits::`nonCoherentAtomSize`.

While a range of device memory is host mapped, the application is responsible for synchronizing both device and host access to that memory range.

| Note It is important for the application developer to become meticulously familiar with all of the mechanisms described in the chapter on Synchronization and Cache Control as they are crucial to maintaining memory access ordering.

Valid Usage

- `memory` must not be currently host mapped

- `offset` must be less than the size of `memory`

- If `size` is not equal to `VK_WHOLE_SIZE`, `size` must be greater than `0`

- If `size` is not equal to `VK_WHOLE_SIZE`, `size` must be less than or equal to the size of the `memory` minus `offset`

- `memory` must have been created with a memory type that reports `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT`

- `memory` must not have been allocated with multiple instances.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `memory` must be a valid VkDeviceMemory handle

- `flags` must be `0`

- `ppData` must be a valid pointer to a pointer value

- `memory` must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `memory` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_MEMORY_MAP_FAILED`

    typedef VkFlags VkMemoryMapFlags;

`VkMemoryMapFlags` is a bitmask type for setting a mask, but is currently reserved for future use.

Two commands are provided to enable applications to work with non-coherent memory allocations: `vkFlushMappedMemoryRanges` and `vkInvalidateMappedMemoryRanges`.

| Note If the memory object was created with the `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT` set, `vkFlushMappedMemoryRanges` and `vkInvalidateMappedMemoryRanges` are unnecessary and may have a performance cost. However, availability and visibility operations still need to be managed on the device. See the description of host access types for more information.

| Note While memory objects imported from a handle type of `VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_ALLOCATION_BIT_EXT` or `VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_MAPPED_FOREIGN_MEMORY_BIT_EXT` are inherently mapped to host address space, they are not considered to be host mapped device memory unless they are explicitly host mapped using vkMapMemory. That means flushing or invalidating host caches with respect to host accesses performed on such memory through the original host pointer specified at import time is the responsibility of the application and must be performed with appropriate synchronization primitives provided by the platform which are outside the scope of Vulkan. `vkFlushMappedMemoryRanges` and `vkInvalidateMappedMemoryRanges`, however, can still be used on such memory objects to synchronize host accesses performed through the host pointer of the host mapped device memory range returned by vkMapMemory.

To flush ranges of non-coherent memory from the host caches, call:

    VkResult vkFlushMappedMemoryRanges(
        VkDevice                                    device,
        uint32_t                                    memoryRangeCount,
        const VkMappedMemoryRange*                  pMemoryRanges);

- `device` is the logical device that owns the memory ranges.

- `memoryRangeCount` is the length of the `pMemoryRanges` array.

- `pMemoryRanges` is a pointer to an array of VkMappedMemoryRange structures describing the memory ranges to flush.

`vkFlushMappedMemoryRanges` guarantees that host writes to the memory ranges described by `pMemoryRanges` are made available to the host memory domain, such that they can be made available to the device memory domain via memory domain operations using the `VK_ACCESS_HOST_WRITE_BIT` access type.

Within each range described by `pMemoryRanges`, each set of `nonCoherentAtomSize` bytes in that range is flushed if any byte in that set has been written by the host since it was first host mapped, or the last time it was flushed. If `pMemoryRanges` includes sets of `nonCoherentAtomSize` bytes where no bytes have been written by the host, those bytes must not be flushed.

Unmapping non-coherent memory does not implicitly flush the host mapped memory, and host writes that have not been flushed may not ever be visible to the device. However, implementations must ensure that writes that have not been flushed do not become visible to any other memory.

| Note The above guarantee avoids a potential memory corruption in scenarios where host writes to a mapped memory object have not been flushed before the memory is unmapped (or freed), and the virtual address range is subsequently reused for a different mapping (or memory allocation).

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pMemoryRanges` must be a valid pointer to an array of `memoryRangeCount` valid VkMappedMemoryRange structures

- `memoryRangeCount` must be greater than `0`

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

To invalidate ranges of non-coherent memory from the host caches, call:

    VkResult vkInvalidateMappedMemoryRanges(
        VkDevice                                    device,
        uint32_t                                    memoryRangeCount,
        const VkMappedMemoryRange*                  pMemoryRanges);

- `device` is the logical device that owns the memory ranges.

- `memoryRangeCount` is the length of the `pMemoryRanges` array.

- `pMemoryRanges` is a pointer to an array of VkMappedMemoryRange structures describing the memory ranges to invalidate.

`vkInvalidateMappedMemoryRanges` guarantees that device writes to the memory ranges described by `pMemoryRanges`, which have been made available to the host memory domain using the `VK_ACCESS_HOST_WRITE_BIT` and `VK_ACCESS_HOST_READ_BIT` access types, are made visible to the host. If a range of non-coherent memory is written by the host and then invalidated without first being flushed, its contents are undefined.

Within each range described by `pMemoryRanges`, each set of `nonCoherentAtomSize` bytes in that range is invalidated if any byte in that set has been written by the device since it was first host mapped, or the last time it was invalidated.

| Note Mapping non-coherent memory does not implicitly invalidate that memory.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pMemoryRanges` must be a valid pointer to an array of `memoryRangeCount` valid VkMappedMemoryRange structures

- `memoryRangeCount` must be greater than `0`

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkMappedMemoryRange` structure is defined as:

    typedef struct VkMappedMemoryRange {
        VkStructureType    sType;
        const void*        pNext;
        VkDeviceMemory     memory;
        VkDeviceSize       offset;
        VkDeviceSize       size;
    } VkMappedMemoryRange;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `memory` is the memory object to which this range belongs.

- `offset` is the zero-based byte offset from the beginning of the memory object.

- `size` is either the size of range, or `VK_WHOLE_SIZE` to affect the range from `offset` to the end of the current mapping of the allocation.

Valid Usage

- `memory` must be currently host mapped

- If `size` is not equal to `VK_WHOLE_SIZE`, `offset` and `size` must specify a range contained within the currently mapped range of `memory`

- If `size` is equal to `VK_WHOLE_SIZE`, `offset` must be within the currently mapped range of `memory`

- If `size` is equal to `VK_WHOLE_SIZE`, the end of the current mapping of `memory` must be a multiple of VkPhysicalDeviceLimits::`nonCoherentAtomSize` bytes from the beginning of the memory object.

- `offset` must be a multiple of VkPhysicalDeviceLimits::`nonCoherentAtomSize`

- If `size` is not equal to `VK_WHOLE_SIZE`, `size` must either be a multiple of VkPhysicalDeviceLimits::`nonCoherentAtomSize`, or `offset` plus `size` must equal the size of `memory`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_MAPPED_MEMORY_RANGE`

- `pNext` must be `NULL`

- `memory` must be a valid VkDeviceMemory handle

To unmap a memory object once host access to it is no longer needed by the application, call:

    void vkUnmapMemory(
        VkDevice                                    device,
        VkDeviceMemory                              memory);

- `device` is the logical device that owns the memory.

- `memory` is the memory object to be unmapped.

Valid Usage

- `memory` must be currently host mapped

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `memory` must be a valid VkDeviceMemory handle

- `memory` must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `memory` must be externally synchronized

#### 10.2.2. Lazily Allocated Memory

If the memory object is allocated from a heap with the `VK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BIT` bit set, that object’s backing memory may be provided by the implementation lazily. The actual committed size of the memory may initially be as small as zero (or as large as the requested size), and monotonically increases as additional memory is needed.

A memory type with this flag set is only allowed to be bound to a `VkImage` whose usage flags include `VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT`.

| Note Using lazily allocated memory objects for framebuffer attachments that are not needed once a render pass instance has completed may allow some implementations to never allocate memory for such attachments.

To determine the amount of lazily-allocated memory that is currently committed for a memory object, call:

    void vkGetDeviceMemoryCommitment(
        VkDevice                                    device,
        VkDeviceMemory                              memory,
        VkDeviceSize*                               pCommittedMemoryInBytes);

- `device` is the logical device that owns the memory.

- `memory` is the memory object being queried.

- `pCommittedMemoryInBytes` is a pointer to a `VkDeviceSize` value in which the number of bytes currently committed is returned, on success.

The implementation may update the commitment at any time, and the value returned by this query may be out of date.

The implementation guarantees to allocate any committed memory from the `heapIndex` indicated by the memory type that the memory object was created with.

Valid Usage

- `memory` must have been created with a memory type that reports `VK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BIT`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `memory` must be a valid VkDeviceMemory handle

- `pCommittedMemoryInBytes` must be a valid pointer to a `VkDeviceSize` value

- `memory` must have been created, allocated, or retrieved from `device`

#### 10.2.3. Protected Memory

Protected memory divides device memory into protected device memory and unprotected device memory.

Protected memory adds the following concepts:

- Memory:

  - Unprotected device memory, which can be visible to the device and can be visible to the host

  - Protected device memory, which can be visible to the device but must not be visible to the host

- Resources:

  - Unprotected images and unprotected buffers, to which unprotected memory can be bound

  - Protected images and protected buffers, to which protected memory can be bound

- Command buffers:

  - Unprotected command buffers, which can be submitted to a device queue to execute unprotected queue operations

  - Protected command buffers, which can be submitted to a protected-capable device queue to execute protected queue operations

- Device queues:

  - Unprotected device queues, to which unprotected command buffers can be submitted

  - Protected-capable device queues, to which unprotected command buffers or protected command buffers can be submitted

- Queue submissions

  - Unprotected queue submissions, through which unprotected command buffers can be submitted

  - Protected queue submissions, through which protected command buffers can be submitted

- Queue operations

  - Unprotected queue operations

  - Protected queue operations

##### Protected Memory Access Rules

If VkPhysicalDeviceProtectedMemoryProperties::`protectedNoFault` is `VK_FALSE`, applications must not perform any of the following operations:

- Write to unprotected memory within protected queue operations.

- Access protected memory within protected queue operations other than in framebuffer-space pipeline stages, the compute shader stage, or the transfer stage.

- Perform a query within protected queue operations.

- Execute an indirect command within protected queue operations.

If VkPhysicalDeviceProtectedMemoryProperties::`protectedNoFault` is `VK_TRUE`, these operations are valid, but reads will return undefined values, and writes will either be dropped or store undefined values.

Whether these operations are valid or not, or if any other invalid usage is performed, the implementation must guarantee that:

- Protected device memory must never be visible to the host.

- Values written to unprotected device memory must not be a function of values from protected memory.

#### 10.2.4. External Memory Handle Types

##### Android Hardware Buffer

Android’s NDK defines AHardwareBuffer objects, which represent device memory that is shareable across processes and that can be accessed by a variety of media APIs and the hardware used to implement them. These Android hardware buffer objects may be imported into VkDeviceMemory objects for access via Vulkan, or exported from Vulkan.

To remove an unnecessary compile-time dependency, an incomplete type definition of AHardwareBuffer is provided in the Vulkan headers:

    struct AHardwareBuffer;

The actual AHardwareBuffer type is defined in Android NDK headers.

| Note The NDK format, usage, and size/dimensions of an AHardwareBuffer object can be obtained with the `AHardwareBuffer_describe` function. While Android hardware buffers can be imported to or exported from Vulkan without using that function, valid usage and implementation behavior is defined in terms of the `AHardwareBuffer_Desc` properties it returns.

Android hardware buffer objects are reference-counted using Android NDK functions outside of the scope of this specification. A VkDeviceMemory imported from an Android hardware buffer or that can be exported to an Android hardware buffer must acquire a reference to its AHardwareBuffer object, and must release this reference when the device memory is freed. During the host execution of a Vulkan command that has an Android hardware buffer as a parameter (including indirect parameters via `pNext` chains), the application must not decrement the Android hardware buffer’s reference count to zero.

Android hardware buffers can be mapped and unmapped for CPU access using the NDK functions. These lock and unlock APIs are considered to acquire and release ownership of the Android hardware buffer, and applications must follow the rules described in External Resource Sharing to transfer ownership between the Vulkan instance and these native APIs.

Android hardware buffers can be shared with external APIs and Vulkan instances on the same device, and also with foreign devices. When transferring ownership of the Android hardware buffer, the external and foreign special queue families described in Queue Family Ownership Transfer are not identical. All APIs which produce or consume Android hardware buffers are considered to use foreign devices, except OpenGL ES contexts and Vulkan logical devices that have matching device and driver UUIDs. Implementations may treat a transfer to or from the foreign queue family as if it were a transfer to or from the external queue family when the Android hardware buffer’s usage only permits it to be used on the same physical device.

###### Android Hardware Buffer Optimal Usages

Vulkan buffer and image usage flags do not correspond exactly to Android hardware buffer usage flags. When allocating Android hardware buffers with non-Vulkan APIs, if any `AHARDWAREBUFFER_USAGE_GPU_`* usage bits are included, by default the allocator must allocate the memory in such a way that it supports Vulkan usages and creation flags in the usage equivalence table which do not have Android hardware buffer equivalents.

An VkAndroidHardwareBufferUsageANDROID structure can be included in the `pNext` chain of a VkImageFormatProperties2 instance passed to vkGetPhysicalDeviceImageFormatProperties2 to obtain optimal Android hardware buffer usage flags for specific Vulkan resource creation parameters. Some usage flags returned by these commands are required based on the input parameters, but additional vendor-specific usage flags (`AHARDWAREBUFFER_USAGE_VENDOR_`*) may also be returned. Any Android hardware buffer allocated with these vendor-specific usage flags and imported to Vulkan must only be bound to resources created with parameters that are a subset of the parameters used to obtain the Android hardware buffer usage, since the memory may have been allocated in a way incompatible with other parameters. If an Android hardware buffer is successfully allocated with additional non-vendor-specific usage flags in addition to the recommended usage, it must support being used in the same ways as an Android hardware buffer allocated with only the recommended usage, and also in ways indicated by the additional usage.

###### Android Hardware Buffer External Formats

Android hardware buffers may represent images using implementation-specific formats, layouts, color models, etc., which do not have Vulkan equivalents. Such external formats are commonly used by external image sources such as video decoders or cameras. Vulkan can import Android hardware buffers that have external formats, but since the image contents are in an undiscoverable and possibly proprietary representation, images with external formats must only be used as sampled images, must only be sampled with a sampler that has Y′CBCR conversion enabled, and must have optimal tiling.

Images that will be backed by an Android hardware buffer can use an external format by setting VkImageCreateInfo::`format` to `VK_FORMAT_UNDEFINED` and including a VkExternalFormatANDROID structure in the `pNext` chain. Images can be created with an external format even if the Android hardware buffer has a format which has an equivalent Vulkan format to enable consistent handling of images from sources that might use either category of format. However, all images created with an external format are subject to the valid usage requirements associated with external formats, even if the Android hardware buffer’s format has a Vulkan equivalent. The external format of an Android hardware buffer can be obtained by passing a VkAndroidHardwareBufferFormatPropertiesANDROID structure to vkGetAndroidHardwareBufferPropertiesANDROID.

###### Android Hardware Buffer Image Resources

Android hardware buffers have intrinsic width, height, format, and usage properties, so Vulkan images bound to memory imported from an Android hardware buffer must use dedicated allocations: `VkMemoryDedicatedRequirements`::`requiresDedicatedAllocation` must be `VK_TRUE` for images created with `VkExternalMemoryImageCreateInfo`::`handleTypes` that includes `VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID`. When creating an image that will be bound to an imported Android hardware buffer, the image creation parameters must be equivalent to the AHardwareBuffer properties as described by the valid usage of VkMemoryAllocateInfo. Similarly, device memory allocated for a dedicated image must not be exported to an Android hardware buffer until it has been bound to that image, and the implementation must return an Android hardware buffer with properties derived from the image:

- The `width` and `height` members of `AHardwareBuffer_Desc` must be the same as the `width` and `height` members of VkImageCreateInfo::`extent`, respectively.

- The `layers` member of `AHardwareBuffer_Desc` must be the same as the `arrayLayers` member of VkImageCreateInfo.

- The `format` member of `AHardwareBuffer_Desc` must be equivalent to VkImageCreateInfo::`format` as defined by AHardwareBuffer Format Equivalence.

- The `usage` member of `AHardwareBuffer_Desc` must include bits corresponding to bits included in VkImageCreateInfo::`usage` and VkImageCreateInfo::`flags` where such a correspondence exists according to AHardwareBuffer Usage Equivalence. It may also include additional usage bits, including vendor-specific usages. Presence of vendor usage bits may make the Android hardware buffer only usable in ways indicated by the image creation parameters, even when used outside Vulkan, in a similar way that allocating the Android hardware buffer with usage returned in VkAndroidHardwareBufferUsageANDROID does.

Implementations may support fewer combinations of image creation parameters for images with Android hardware buffer external handle type than for non-external images. Support for a given set of parameters can be determined by passing VkExternalImageFormatProperties to vkGetPhysicalDeviceImageFormatProperties2 with `handleType` set to `VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID`. Any Android hardware buffer successfully allocated outside Vulkan with usage that includes `AHARDWAREBUFFER_USAGE_GPU_`* must be supported when using equivalent Vulkan image parameters. If a given choice of image parameters are supported for import, they can also be used to create an image and memory that will be exported to an Android hardware buffer.

Table 13. AHardwareBuffer Format Equivalence
AHardwareBuffer Format | Vulkan Format
--- | ---
`AHARDWAREBUFFER_FORMAT_R8G8B8A8_UNORM` | `VK_FORMAT_R8G8B8A8_UNORM`
`AHARDWAREBUFFER_FORMAT_R8G8B8X8_UNORM` 1 | `VK_FORMAT_R8G8B8A8_UNORM`
`AHARDWAREBUFFER_FORMAT_R8G8B8_UNORM` | `VK_FORMAT_R8G8B8_UNORM`
`AHARDWAREBUFFER_FORMAT_R5G6B5_UNORM` | `VK_FORMAT_R5G6B5_UNORM_PACK16`
`AHARDWAREBUFFER_FORMAT_R16G16B16A16_FLOAT` | `VK_FORMAT_R16G16B16A16_SFLOAT`
`AHARDWAREBUFFER_FORMAT_R10G10B10A2_UNORM` | `VK_FORMAT_A2B10G10R10_UNORM_PACK32`
`AHARDWAREBUFFER_FORMAT_D16_UNORM` | `VK_FORMAT_D16_UNORM`
`AHARDWAREBUFFER_FORMAT_D24_UNORM` | `VK_FORMAT_X8_D24_UNORM_PACK32`
`AHARDWAREBUFFER_FORMAT_D24_UNORM_S8_UINT` | `VK_FORMAT_D24_UNORM_S8_UINT`
`AHARDWAREBUFFER_FORMAT_D32_FLOAT` | `VK_FORMAT_D32_SFLOAT`
`AHARDWAREBUFFER_FORMAT_D32_FLOAT_S8_UINT` | `VK_FORMAT_D32_SFLOAT_S8_UINT`
`AHARDWAREBUFFER_FORMAT_S8_UINT` | `VK_FORMAT_S8_UINT`

Table 14. AHardwareBuffer Usage Equivalence
AHardwareBuffer Usage | Vulkan Usage or Creation Flag
--- | ---
None | `VK_IMAGE_USAGE_TRANSFER_SRC_BIT`
None | `VK_IMAGE_USAGE_TRANSFER_DST_BIT`
`AHARDWAREBUFFER_USAGE_GPU_SAMPLED_IMAGE` | `VK_IMAGE_USAGE_SAMPLED_BIT`
`AHARDWAREBUFFER_USAGE_GPU_SAMPLED_IMAGE` | `VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT`
`AHARDWAREBUFFER_USAGE_GPU_COLOR_OUTPUT` | `VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT`
`AHARDWAREBUFFER_USAGE_GPU_CUBE_MAP` | `VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT`
`AHARDWAREBUFFER_USAGE_GPU_MIPMAP_COMPLETE` | None 2
`AHARDWAREBUFFER_USAGE_PROTECTED_CONTENT` | `VK_IMAGE_CREATE_PROTECTED_BIT`
None | `VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT`
None | `VK_IMAGE_CREATE_EXTENDED_USAGE_BIT`

1

  Vulkan does not differentiate between `AHARDWAREBUFFER_FORMAT_R8G8B8A8_UNORM` and `AHARDWAREBUFFER_FORMAT_R8G8B8X8_UNORM`: they both behave as `VK_FORMAT_R8G8B8A8_UNORM`. After an external entity writes to a `AHARDWAREBUFFER_FORMAT_R8G8B8X8_UNORM` Android hardware buffer, the values read by Vulkan from the X/A channel are undefined. To emulate the traditional behavior of the X channel during sampling or blending, applications should use `VK_COMPONENT_SWIZZLE_ONE` in image view component mappings and `VK_BLEND_FACTOR_ONE` in color blend factors. There is no way to avoid copying these undefined values when copying from such an image to another image or buffer.

2

  The `AHARDWAREBUFFER_USAGE_GPU_MIPMAP_COMPLETE` flag does not correspond to a Vulkan image usage or creation flag. Instead, its presence indicates that the Android hardware buffer contains a complete mipmap chain, and its absence indicates that the Android hardware buffer contains only a single mip level.

| Note When using `VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT` with Android hardware buffer images, applications should use VkImageFormatListCreateInfo to inform the implementation which view formats will be used with the image. For some common sets of format, this allows some implementations to provide significantly better performance when accessing the image via Vulkan.

###### Android Hardware Buffer Buffer Resources

Android hardware buffers with a format of `AHARDWAREBUFFER_FORMAT_BLOB` and usage that includes `AHARDWAREBUFFER_USAGE_GPU_DATA_BUFFER` can be used as the backing store for VkBuffer objects. Such Android hardware buffers have a size in bytes specified by their `width`; `height` and `layers` are both `1`.

Unlike images, buffer resources backed by Android hardware buffers do not require dedicated allocations.

Exported AHardwareBuffer objects that do not have dedicated images must have a format of `AHARDWAREBUFFER_FORMAT_BLOB`, usage must include `AHARDWAREBUFFER_USAGE_GPU_DATA_BUFFER`, `width` must equal the device memory allocation size, and `height` and `layers` must be `1`.

#### 10.2.5. Peer Memory Features

Peer memory is memory that is allocated for a given physical device and then bound to a resource and accessed by a different physical device, in a logical device that represents multiple physical devices. Some ways of reading and writing peer memory may not be supported by a device.

To determine how peer memory can be accessed, call:

    void vkGetDeviceGroupPeerMemoryFeatures(
        VkDevice                                    device,
        uint32_t                                    heapIndex,
        uint32_t                                    localDeviceIndex,
        uint32_t                                    remoteDeviceIndex,
        VkPeerMemoryFeatureFlags*                   pPeerMemoryFeatures);

or the equivalent command

    void vkGetDeviceGroupPeerMemoryFeaturesKHR(
        VkDevice                                    device,
        uint32_t                                    heapIndex,
        uint32_t                                    localDeviceIndex,
        uint32_t                                    remoteDeviceIndex,
        VkPeerMemoryFeatureFlags*                   pPeerMemoryFeatures);

- `device` is the logical device that owns the memory.

- `heapIndex` is the index of the memory heap from which the memory is allocated.

- `localDeviceIndex` is the device index of the physical device that performs the memory access.

- `remoteDeviceIndex` is the device index of the physical device that the memory is allocated for.

- `pPeerMemoryFeatures` is a pointer to a VkPeerMemoryFeatureFlags bitmask indicating which types of memory accesses are supported for the combination of heap, local, and remote devices.

Valid Usage

- `heapIndex` must be less than `memoryHeapCount`

- `localDeviceIndex` must be a valid device index

- `remoteDeviceIndex` must be a valid device index

- `localDeviceIndex` must not equal `remoteDeviceIndex`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pPeerMemoryFeatures` must be a valid pointer to a VkPeerMemoryFeatureFlags value

Bits which may be set in the value returned for vkGetDeviceGroupPeerMemoryFeatures::`pPeerMemoryFeatures`, indicating the supported peer memory features, are:

    typedef enum VkPeerMemoryFeatureFlagBits {
        VK_PEER_MEMORY_FEATURE_COPY_SRC_BIT = 0x00000001,
        VK_PEER_MEMORY_FEATURE_COPY_DST_BIT = 0x00000002,
        VK_PEER_MEMORY_FEATURE_GENERIC_SRC_BIT = 0x00000004,
        VK_PEER_MEMORY_FEATURE_GENERIC_DST_BIT = 0x00000008,
        VK_PEER_MEMORY_FEATURE_COPY_SRC_BIT_KHR = VK_PEER_MEMORY_FEATURE_COPY_SRC_BIT,
        VK_PEER_MEMORY_FEATURE_COPY_DST_BIT_KHR = VK_PEER_MEMORY_FEATURE_COPY_DST_BIT,
        VK_PEER_MEMORY_FEATURE_GENERIC_SRC_BIT_KHR = VK_PEER_MEMORY_FEATURE_GENERIC_SRC_BIT,
        VK_PEER_MEMORY_FEATURE_GENERIC_DST_BIT_KHR = VK_PEER_MEMORY_FEATURE_GENERIC_DST_BIT,
        VK_PEER_MEMORY_FEATURE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkPeerMemoryFeatureFlagBits;

or the equivalent

    typedef VkPeerMemoryFeatureFlagBits VkPeerMemoryFeatureFlagBitsKHR;

- `VK_PEER_MEMORY_FEATURE_COPY_SRC_BIT` specifies that the memory can be accessed as the source of a vkCmdCopyBuffer, vkCmdCopyImage, vkCmdCopyBufferToImage, or vkCmdCopyImageToBuffer command.

- `VK_PEER_MEMORY_FEATURE_COPY_DST_BIT` specifies that the memory can be accessed as the destination of a vkCmdCopyBuffer, vkCmdCopyImage, vkCmdCopyBufferToImage, or vkCmdCopyImageToBuffer command.

- `VK_PEER_MEMORY_FEATURE_GENERIC_SRC_BIT` specifies that the memory can be read as any memory access type.

- `VK_PEER_MEMORY_FEATURE_GENERIC_DST_BIT` specifies that the memory can be written as any memory access type. Shader atomics are considered to be writes.

| Note The peer memory features of a memory heap also apply to any accesses that may be performed during image layout transitions.

`VK_PEER_MEMORY_FEATURE_COPY_DST_BIT` must be supported for all host local heaps and for at least one device local heap.

If a device does not support a peer memory feature, it is still valid to use a resource that includes both local and peer memory bindings with the corresponding access type as long as only the local bindings are actually accessed. For example, an application doing split-frame rendering would use framebuffer attachments that include both local and peer memory bindings, but would scissor the rendering to only update local memory.

    typedef VkFlags VkPeerMemoryFeatureFlags;

or the equivalent

    typedef VkPeerMemoryFeatureFlags VkPeerMemoryFeatureFlagsKHR;

`VkPeerMemoryFeatureFlags` is a bitmask type for setting a mask of zero or more VkPeerMemoryFeatureFlagBits.

To query a 64-bit opaque capture address value from a memory object, call:

    uint64_t vkGetDeviceMemoryOpaqueCaptureAddress(
        VkDevice                                    device,
        const VkDeviceMemoryOpaqueCaptureAddressInfo* pInfo);

or the equivalent command

    uint64_t vkGetDeviceMemoryOpaqueCaptureAddressKHR(
        VkDevice                                    device,
        const VkDeviceMemoryOpaqueCaptureAddressInfo* pInfo);

- `device` is the logical device that the memory object was allocated on.

- `pInfo` is a pointer to a VkDeviceMemoryOpaqueCaptureAddressInfo structure specifying the memory object to retrieve an address for.

The 64-bit return value is an opaque address representing the start of `pInfo->memory`.

If the memory object was allocated with a non-zero value of VkMemoryOpaqueCaptureAddressAllocateInfo::`opaqueCaptureAddress`, the return value must be the same address.

| Note The expected usage for these opaque addresses is only for trace capture/replay tools to store these addresses in a trace and subsequently specify them during replay.

Valid Usage

- The bufferDeviceAddress feature must be enabled

- If `device` was created with multiple physical devices, then the bufferDeviceAddressMultiDevice feature must be enabled

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pInfo` must be a valid pointer to a valid VkDeviceMemoryOpaqueCaptureAddressInfo structure

The `VkDeviceMemoryOpaqueCaptureAddressInfo` structure is defined as:

    typedef struct VkDeviceMemoryOpaqueCaptureAddressInfo {
        VkStructureType    sType;
        const void*        pNext;
        VkDeviceMemory     memory;
    } VkDeviceMemoryOpaqueCaptureAddressInfo;

or the equivalent

    typedef VkDeviceMemoryOpaqueCaptureAddressInfo VkDeviceMemoryOpaqueCaptureAddressInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `memory` specifies the memory whose address is being queried.

Valid Usage

- `memory` must have been allocated with `VK_MEMORY_ALLOCATE_DEVICE_ADDRESS_BIT`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEVICE_MEMORY_OPAQUE_CAPTURE_ADDRESS_INFO`

- `pNext` must be `NULL`

- `memory` must be a valid VkDeviceMemory handle

## 11. Resource Creation

Vulkan supports two primary resource types: buffers and images. Resources are views of memory with associated formatting and dimensionality. Buffers are essentially unformatted arrays of bytes whereas images contain format information, can be multidimensional and may have associated metadata.

### 11.1. Buffers

Buffers represent linear arrays of data which are used for various purposes by binding them to a graphics or compute pipeline via descriptor sets or via certain commands, or by directly specifying them as parameters to certain commands.

Buffers are represented by `VkBuffer` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkBuffer)

To create buffers, call:

    VkResult vkCreateBuffer(
        VkDevice                                    device,
        const VkBufferCreateInfo*                   pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkBuffer*                                   pBuffer);

- `device` is the logical device that creates the buffer object.

- `pCreateInfo` is a pointer to a `VkBufferCreateInfo` structure containing parameters affecting creation of the buffer.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pBuffer` is a pointer to a VkBuffer handle in which the resulting buffer object is returned.

Valid Usage

- If the `flags` member of `pCreateInfo` includes `VK_BUFFER_CREATE_SPARSE_BINDING_BIT`, creating this `VkBuffer` must not cause the total required sparse memory for all currently valid sparse resources on the device to exceed `VkPhysicalDeviceLimits`::`sparseAddressSpaceSize`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkBufferCreateInfo structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pBuffer` must be a valid pointer to a VkBuffer handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_INVALID_OPAQUE_CAPTURE_ADDRESS_KHR`

The `VkBufferCreateInfo` structure is defined as:

    typedef struct VkBufferCreateInfo {
        VkStructureType        sType;
        const void*            pNext;
        VkBufferCreateFlags    flags;
        VkDeviceSize           size;
        VkBufferUsageFlags     usage;
        VkSharingMode          sharingMode;
        uint32_t               queueFamilyIndexCount;
        const uint32_t*        pQueueFamilyIndices;
    } VkBufferCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkBufferCreateFlagBits specifying additional parameters of the buffer.

- `size` is the size in bytes of the buffer to be created.

- `usage` is a bitmask of VkBufferUsageFlagBits specifying allowed usages of the buffer.

- `sharingMode` is a VkSharingMode value specifying the sharing mode of the buffer when it will be accessed by multiple queue families.

- `queueFamilyIndexCount` is the number of entries in the `pQueueFamilyIndices` array.

- `pQueueFamilyIndices` is a list of queue families that will access this buffer (ignored if `sharingMode` is not `VK_SHARING_MODE_CONCURRENT`).

Valid Usage

- `size` must be greater than `0`

- If `sharingMode` is `VK_SHARING_MODE_CONCURRENT`, `pQueueFamilyIndices` must be a valid pointer to an array of `queueFamilyIndexCount` `uint32_t` values

- If `sharingMode` is `VK_SHARING_MODE_CONCURRENT`, `queueFamilyIndexCount` must be greater than `1`

- If `sharingMode` is `VK_SHARING_MODE_CONCURRENT`, each element of `pQueueFamilyIndices` must be unique and must be less than `pQueueFamilyPropertyCount` returned by either vkGetPhysicalDeviceQueueFamilyProperties or vkGetPhysicalDeviceQueueFamilyProperties2 for the `physicalDevice` that was used to create `device`

- If the sparse bindings feature is not enabled, `flags` must not contain `VK_BUFFER_CREATE_SPARSE_BINDING_BIT`

- If the sparse buffer residency feature is not enabled, `flags` must not contain `VK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT`

- If the sparse aliased residency feature is not enabled, `flags` must not contain `VK_BUFFER_CREATE_SPARSE_ALIASED_BIT`

- If `flags` contains `VK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT` or `VK_BUFFER_CREATE_SPARSE_ALIASED_BIT`, it must also contain `VK_BUFFER_CREATE_SPARSE_BINDING_BIT`

- If the `pNext` chain includes a VkExternalMemoryBufferCreateInfo structure, its `handleTypes` member must only contain bits that are also in VkExternalBufferProperties::`externalMemoryProperties.compatibleHandleTypes`, as returned by vkGetPhysicalDeviceExternalBufferProperties with `pExternalBufferInfo->handleType` equal to any one of the handle types specified in VkExternalMemoryBufferCreateInfo::`handleTypes`

- If the protected memory feature is not enabled, `flags` must not contain `VK_BUFFER_CREATE_PROTECTED_BIT`

- If any of the bits `VK_BUFFER_CREATE_SPARSE_BINDING_BIT`, `VK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT`, or `VK_BUFFER_CREATE_SPARSE_ALIASED_BIT` are set, `VK_BUFFER_CREATE_PROTECTED_BIT` must not also be set

- If the `pNext` chain includes a VkDedicatedAllocationBufferCreateInfoNV structure, and the `dedicatedAllocation` member of the chained structure is `VK_TRUE`, then `flags` must not include `VK_BUFFER_CREATE_SPARSE_BINDING_BIT`, `VK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT`, or `VK_BUFFER_CREATE_SPARSE_ALIASED_BIT`

- If VkBufferDeviceAddressCreateInfoEXT::`deviceAddress` is not zero, `flags` must include `VK_BUFFER_CREATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT`

- If VkBufferOpaqueCaptureAddressCreateInfo::`opaqueCaptureAddress` is not zero, `flags` must include `VK_BUFFER_CREATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT`

- If `flags` includes `VK_BUFFER_CREATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT`, the bufferDeviceAddressCaptureReplay or `VkPhysicalDeviceBufferDeviceAddressFeaturesEXT`::`bufferDeviceAddressCaptureReplay` feature must be enabled

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkBufferDeviceAddressCreateInfoEXT, VkBufferOpaqueCaptureAddressCreateInfo, VkDedicatedAllocationBufferCreateInfoNV, or VkExternalMemoryBufferCreateInfo

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be a valid combination of VkBufferCreateFlagBits values

- `usage` must be a valid combination of VkBufferUsageFlagBits values

- `usage` must not be `0`

- `sharingMode` must be a valid VkSharingMode value

Bits which can be set in VkBufferCreateInfo::`usage`, specifying usage behavior of a buffer, are:

    typedef enum VkBufferUsageFlagBits {
        VK_BUFFER_USAGE_TRANSFER_SRC_BIT = 0x00000001,
        VK_BUFFER_USAGE_TRANSFER_DST_BIT = 0x00000002,
        VK_BUFFER_USAGE_UNIFORM_TEXEL_BUFFER_BIT = 0x00000004,
        VK_BUFFER_USAGE_STORAGE_TEXEL_BUFFER_BIT = 0x00000008,
        VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT = 0x00000010,
        VK_BUFFER_USAGE_STORAGE_BUFFER_BIT = 0x00000020,
        VK_BUFFER_USAGE_INDEX_BUFFER_BIT = 0x00000040,
        VK_BUFFER_USAGE_VERTEX_BUFFER_BIT = 0x00000080,
        VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT = 0x00000100,
        VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT = 0x00020000,
        VK_BUFFER_USAGE_TRANSFORM_FEEDBACK_BUFFER_BIT_EXT = 0x00000800,
        VK_BUFFER_USAGE_TRANSFORM_FEEDBACK_COUNTER_BUFFER_BIT_EXT = 0x00001000,
        VK_BUFFER_USAGE_CONDITIONAL_RENDERING_BIT_EXT = 0x00000200,
        VK_BUFFER_USAGE_RAY_TRACING_BIT_KHR = 0x00000400,
        VK_BUFFER_USAGE_RAY_TRACING_BIT_NV = VK_BUFFER_USAGE_RAY_TRACING_BIT_KHR,
        VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT_EXT = VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT,
        VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT_KHR = VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT,
        VK_BUFFER_USAGE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkBufferUsageFlagBits;

- `VK_BUFFER_USAGE_TRANSFER_SRC_BIT` specifies that the buffer can be used as the source of a transfer command (see the definition of `VK_PIPELINE_STAGE_TRANSFER_BIT`).

- `VK_BUFFER_USAGE_TRANSFER_DST_BIT` specifies that the buffer can be used as the destination of a transfer command.

- `VK_BUFFER_USAGE_UNIFORM_TEXEL_BUFFER_BIT` specifies that the buffer can be used to create a `VkBufferView` suitable for occupying a `VkDescriptorSet` slot of type `VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER`.

- `VK_BUFFER_USAGE_STORAGE_TEXEL_BUFFER_BIT` specifies that the buffer can be used to create a `VkBufferView` suitable for occupying a `VkDescriptorSet` slot of type `VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER`.

- `VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT` specifies that the buffer can be used in a `VkDescriptorBufferInfo` suitable for occupying a `VkDescriptorSet` slot either of type `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER` or `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC`.

- `VK_BUFFER_USAGE_STORAGE_BUFFER_BIT` specifies that the buffer can be used in a `VkDescriptorBufferInfo` suitable for occupying a `VkDescriptorSet` slot either of type `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER` or `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC`.

- `VK_BUFFER_USAGE_INDEX_BUFFER_BIT` specifies that the buffer is suitable for passing as the `buffer` parameter to `vkCmdBindIndexBuffer`.

- `VK_BUFFER_USAGE_VERTEX_BUFFER_BIT` specifies that the buffer is suitable for passing as an element of the `pBuffers` array to `vkCmdBindVertexBuffers`.

- `VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT` specifies that the buffer is suitable for passing as the `buffer` parameter to `vkCmdDrawIndirect`, `vkCmdDrawIndexedIndirect`, `vkCmdDrawMeshTasksIndirectNV`, `vkCmdDrawMeshTasksIndirectCountNV`, or `vkCmdDispatchIndirect`. It is also suitable for passing as the `buffer` member of `VkIndirectCommandsStreamNV`, or `sequencesCountBuffer` or `sequencesIndexBuffer` or `preprocessedBuffer` member of `VkGeneratedCommandsInfoNV`

- `VK_BUFFER_USAGE_CONDITIONAL_RENDERING_BIT_EXT` specifies that the buffer is suitable for passing as the `buffer` parameter to vkCmdBeginConditionalRenderingEXT.

- `VK_BUFFER_USAGE_TRANSFORM_FEEDBACK_BUFFER_BIT_EXT` specifies that the buffer is suitable for using for binding as a transform feedback buffer with vkCmdBindTransformFeedbackBuffersEXT.

- `VK_BUFFER_USAGE_TRANSFORM_FEEDBACK_COUNTER_BUFFER_BIT_EXT` specifies that the buffer is suitable for using as a counter buffer with vkCmdBeginTransformFeedbackEXT and vkCmdEndTransformFeedbackEXT.

- `VK_BUFFER_USAGE_RAY_TRACING_BIT_KHR` specifies that the buffer is suitable for use in vkCmdTraceRaysKHR and vkCmdBuildAccelerationStructureKHR.

- `VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT` specifies that the buffer can be used to retrieve a buffer device address via vkGetBufferDeviceAddress and use that address to access the buffer’s memory from a shader.

    typedef VkFlags VkBufferUsageFlags;

`VkBufferUsageFlags` is a bitmask type for setting a mask of zero or more VkBufferUsageFlagBits.

Bits which can be set in VkBufferCreateInfo::`flags`, specifying additional parameters of a buffer, are:

    typedef enum VkBufferCreateFlagBits {
        VK_BUFFER_CREATE_SPARSE_BINDING_BIT = 0x00000001,
        VK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT = 0x00000002,
        VK_BUFFER_CREATE_SPARSE_ALIASED_BIT = 0x00000004,
        VK_BUFFER_CREATE_PROTECTED_BIT = 0x00000008,
        VK_BUFFER_CREATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT = 0x00000010,
        VK_BUFFER_CREATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT_EXT = VK_BUFFER_CREATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT,
        VK_BUFFER_CREATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT_KHR = VK_BUFFER_CREATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT,
        VK_BUFFER_CREATE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkBufferCreateFlagBits;

- `VK_BUFFER_CREATE_SPARSE_BINDING_BIT` specifies that the buffer will be backed using sparse memory binding.

- `VK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT` specifies that the buffer can be partially backed using sparse memory binding. Buffers created with this flag must also be created with the `VK_BUFFER_CREATE_SPARSE_BINDING_BIT` flag.

- `VK_BUFFER_CREATE_SPARSE_ALIASED_BIT` specifies that the buffer will be backed using sparse memory binding with memory ranges that might also simultaneously be backing another buffer (or another portion of the same buffer). Buffers created with this flag must also be created with the `VK_BUFFER_CREATE_SPARSE_BINDING_BIT` flag.

- `VK_BUFFER_CREATE_PROTECTED_BIT` specifies that the buffer is a protected buffer.

- `VK_BUFFER_CREATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT` specifies that the buffer’s address can be saved and reused on a subsequent run (e.g. for trace capture and replay), see VkBufferOpaqueCaptureAddressCreateInfo for more detail.

See Sparse Resource Features and Physical Device Features for details of the sparse memory features supported on a device.

    typedef VkFlags VkBufferCreateFlags;

`VkBufferCreateFlags` is a bitmask type for setting a mask of zero or more VkBufferCreateFlagBits.

If the `pNext` chain includes a `VkDedicatedAllocationBufferCreateInfoNV` structure, then that structure includes an enable controlling whether the buffer will have a dedicated memory allocation bound to it.

The `VkDedicatedAllocationBufferCreateInfoNV` structure is defined as:

    typedef struct VkDedicatedAllocationBufferCreateInfoNV {
        VkStructureType    sType;
        const void*        pNext;
        VkBool32           dedicatedAllocation;
    } VkDedicatedAllocationBufferCreateInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `dedicatedAllocation` specifies whether the buffer will have a dedicated allocation bound to it.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_BUFFER_CREATE_INFO_NV`

To define a set of external memory handle types that may be used as backing store for a buffer, add a VkExternalMemoryBufferCreateInfo structure to the `pNext` chain of the VkBufferCreateInfo structure. The `VkExternalMemoryBufferCreateInfo` structure is defined as:

    typedef struct VkExternalMemoryBufferCreateInfo {
        VkStructureType                    sType;
        const void*                        pNext;
        VkExternalMemoryHandleTypeFlags    handleTypes;
    } VkExternalMemoryBufferCreateInfo;

or the equivalent

    typedef VkExternalMemoryBufferCreateInfo VkExternalMemoryBufferCreateInfoKHR;

| Note A `VkExternalMemoryBufferCreateInfo` structure must be included in the creation parameters for a buffer that will be bound to memory that is either exported or imported.

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `handleTypes` is a bitmask of VkExternalMemoryHandleTypeFlagBits specifying one or more external memory handle types.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_BUFFER_CREATE_INFO`

- `handleTypes` must be a valid combination of VkExternalMemoryHandleTypeFlagBits values

To request a specific device address for a buffer, add a VkBufferOpaqueCaptureAddressCreateInfo structure to the `pNext` chain of the VkBufferCreateInfo structure. The `VkBufferOpaqueCaptureAddressCreateInfo` structure is defined as:

    typedef struct VkBufferOpaqueCaptureAddressCreateInfo {
        VkStructureType    sType;
        const void*        pNext;
        uint64_t           opaqueCaptureAddress;
    } VkBufferOpaqueCaptureAddressCreateInfo;

or the equivalent

    typedef VkBufferOpaqueCaptureAddressCreateInfo VkBufferOpaqueCaptureAddressCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `opaqueCaptureAddress` is the opaque capture address requested for the buffer.

If `opaqueCaptureAddress` is zero, no specific address is requested.

If `opaqueCaptureAddress` is not zero, then it should be an address retrieved from vkGetBufferOpaqueCaptureAddress for an identically created buffer on the same implementation.

If this structure is not present, it is as if `opaqueCaptureAddress` is zero.

Apps should avoid creating buffers with app-provided addresses and implementation-provided addresses in the same process, to reduce the likelihood of `VK_ERROR_INVALID_OPAQUE_CAPTURE_ADDRESS` errors.

| Note The expected usage for this is that a trace capture/replay tool will add the `VK_BUFFER_CREATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT` flag to all buffers that use `VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT`, and during capture will save the queried opaque device addresses in the trace. During replay, the buffers will be created specifying the original address so any address values stored in the trace data will remain valid. Implementations are expected to separate such buffers in the GPU address space so normal allocations will avoid using these addresses. Apps/tools should avoid mixing app-provided and implementation-provided addresses for buffers created with `VK_BUFFER_CREATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT`, to avoid address space allocation conflicts.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_BUFFER_OPAQUE_CAPTURE_ADDRESS_CREATE_INFO`

Alternatively, to request a specific device address for a buffer, add a VkBufferDeviceAddressCreateInfoEXT structure to the `pNext` chain of the VkBufferCreateInfo structure. The `VkBufferDeviceAddressCreateInfoEXT` structure is defined as:

    typedef struct VkBufferDeviceAddressCreateInfoEXT {
        VkStructureType    sType;
        const void*        pNext;
        VkDeviceAddress    deviceAddress;
    } VkBufferDeviceAddressCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `deviceAddress` is the device address requested for the buffer.

If `deviceAddress` is zero, no specific address is requested.

If `deviceAddress` is not zero, then it must be an address retrieved from an identically created buffer on the same implementation. The buffer must also be bound to an identically created `VkDeviceMemory` object.

If this structure is not present, it is as if `deviceAddress` is zero.

Apps should avoid creating buffers with app-provided addresses and implementation-provided addresses in the same process, to reduce the likelihood of `VK_ERROR_INVALID_DEVICE_ADDRESS_EXT` errors.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_BUFFER_DEVICE_ADDRESS_CREATE_INFO_EXT`

To destroy a buffer, call:

    void vkDestroyBuffer(
        VkDevice                                    device,
        VkBuffer                                    buffer,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that destroys the buffer.

- `buffer` is the buffer to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage

- All submitted commands that refer to `buffer`, either directly or via a `VkBufferView`, must have completed execution

- If `VkAllocationCallbacks` were provided when `buffer` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `buffer` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `buffer` is not VK_NULL_HANDLE, `buffer` must be a valid VkBuffer handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- If `buffer` is a valid handle, it must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `buffer` must be externally synchronized

### 11.2. Buffer Views

A buffer view represents a contiguous range of a buffer and a specific format to be used to interpret the data. Buffer views are used to enable shaders to access buffer contents interpreted as formatted data. In order to create a valid buffer view, the buffer must have been created with at least one of the following usage flags:

- `VK_BUFFER_USAGE_UNIFORM_TEXEL_BUFFER_BIT`

- `VK_BUFFER_USAGE_STORAGE_TEXEL_BUFFER_BIT`

Buffer views are represented by `VkBufferView` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkBufferView)

To create a buffer view, call:

    VkResult vkCreateBufferView(
        VkDevice                                    device,
        const VkBufferViewCreateInfo*               pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkBufferView*                               pView);

- `device` is the logical device that creates the buffer view.

- `pCreateInfo` is a pointer to a `VkBufferViewCreateInfo` structure containing parameters to be used to create the buffer.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pView` is a pointer to a VkBufferView handle in which the resulting buffer view object is returned.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkBufferViewCreateInfo structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pView` must be a valid pointer to a VkBufferView handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkBufferViewCreateInfo` structure is defined as:

    typedef struct VkBufferViewCreateInfo {
        VkStructureType            sType;
        const void*                pNext;
        VkBufferViewCreateFlags    flags;
        VkBuffer                   buffer;
        VkFormat                   format;
        VkDeviceSize               offset;
        VkDeviceSize               range;
    } VkBufferViewCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `buffer` is a VkBuffer on which the view will be created.

- `format` is a VkFormat describing the format of the data elements in the buffer.

- `offset` is an offset in bytes from the base address of the buffer. Accesses to the buffer view from shaders use addressing that is relative to this starting offset.

- `range` is a size in bytes of the buffer view. If `range` is equal to `VK_WHOLE_SIZE`, the range from `offset` to the end of the buffer is used. If `VK_WHOLE_SIZE` is used and the remaining size of the buffer is not a multiple of the texel block size of `format`, the nearest smaller multiple is used.

Valid Usage

- `offset` must be less than the size of `buffer`

- If `range` is not equal to `VK_WHOLE_SIZE`, `range` must be greater than `0`

- If `range` is not equal to `VK_WHOLE_SIZE`, `range` must be an integer multiple of the texel block size of `format`

- If `range` is not equal to `VK_WHOLE_SIZE`, `range` divided by the texel block size of `format`, multiplied by the number of texels per texel block for that format (as defined in the Compatible Formats table), must be less than or equal to `VkPhysicalDeviceLimits`::`maxTexelBufferElements`

- If `range` is not equal to `VK_WHOLE_SIZE`, the sum of `offset` and `range` must be less than or equal to the size of `buffer`

- `buffer` must have been created with a `usage` value containing at least one of `VK_BUFFER_USAGE_UNIFORM_TEXEL_BUFFER_BIT` or `VK_BUFFER_USAGE_STORAGE_TEXEL_BUFFER_BIT`

- If `buffer` was created with `usage` containing `VK_BUFFER_USAGE_UNIFORM_TEXEL_BUFFER_BIT`, `format` must be supported for uniform texel buffers, as specified by the `VK_FORMAT_FEATURE_UNIFORM_TEXEL_BUFFER_BIT` flag in `VkFormatProperties`::`bufferFeatures` returned by `vkGetPhysicalDeviceFormatProperties`

- If `buffer` was created with `usage` containing `VK_BUFFER_USAGE_STORAGE_TEXEL_BUFFER_BIT`, `format` must be supported for storage texel buffers, as specified by the `VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_BIT` flag in `VkFormatProperties`::`bufferFeatures` returned by `vkGetPhysicalDeviceFormatProperties`

- If `buffer` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- If the texelBufferAlignment feature is not enabled, `offset` must be a multiple of `VkPhysicalDeviceLimits`::`minTexelBufferOffsetAlignment`

- If the texelBufferAlignment feature is enabled and if `buffer` was created with `usage` containing `VK_BUFFER_USAGE_STORAGE_TEXEL_BUFFER_BIT`, `offset` must be a multiple of the lesser of VkPhysicalDeviceTexelBufferAlignmentPropertiesEXT::`storageTexelBufferOffsetAlignmentBytes` or, if VkPhysicalDeviceTexelBufferAlignmentPropertiesEXT::`storageTexelBufferOffsetSingleTexelAlignment` is `VK_TRUE`, the size of a texel of the requested `format`. If the size of a texel is a multiple of three bytes, then the size of a single component of `format` is used instead

- If the texelBufferAlignment feature is enabled and if `buffer` was created with `usage` containing `VK_BUFFER_USAGE_UNIFORM_TEXEL_BUFFER_BIT`, `offset` must be a multiple of the lesser of VkPhysicalDeviceTexelBufferAlignmentPropertiesEXT::`uniformTexelBufferOffsetAlignmentBytes` or, if VkPhysicalDeviceTexelBufferAlignmentPropertiesEXT::`uniformTexelBufferOffsetSingleTexelAlignment` is `VK_TRUE`, the size of a texel of the requested `format`. If the size of a texel is a multiple of three bytes, then the size of a single component of `format` is used instead

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_BUFFER_VIEW_CREATE_INFO`

- `pNext` must be `NULL`

- `flags` must be `0`

- `buffer` must be a valid VkBuffer handle

- `format` must be a valid VkFormat value

    typedef VkFlags VkBufferViewCreateFlags;

`VkBufferViewCreateFlags` is a bitmask type for setting a mask, but is currently reserved for future use.

To destroy a buffer view, call:

    void vkDestroyBufferView(
        VkDevice                                    device,
        VkBufferView                                bufferView,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that destroys the buffer view.

- `bufferView` is the buffer view to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage

- All submitted commands that refer to `bufferView` must have completed execution

- If `VkAllocationCallbacks` were provided when `bufferView` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `bufferView` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `bufferView` is not VK_NULL_HANDLE, `bufferView` must be a valid VkBufferView handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- If `bufferView` is a valid handle, it must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `bufferView` must be externally synchronized

### 11.3. Images

Images represent multidimensional - up to 3 - arrays of data which can be used for various purposes (e.g. attachments, textures), by binding them to a graphics or compute pipeline via descriptor sets, or by directly specifying them as parameters to certain commands.

Images are represented by `VkImage` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkImage)

To create images, call:

    VkResult vkCreateImage(
        VkDevice                                    device,
        const VkImageCreateInfo*                    pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkImage*                                    pImage);

- `device` is the logical device that creates the image.

- `pCreateInfo` is a pointer to a `VkImageCreateInfo` structure containing parameters to be used to create the image.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pImage` is a pointer to a VkImage handle in which the resulting image object is returned.

Valid Usage

- If the `flags` member of `pCreateInfo` includes `VK_IMAGE_CREATE_SPARSE_BINDING_BIT`, creating this `VkImage` must not cause the total required sparse memory for all currently valid sparse resources on the device to exceed `VkPhysicalDeviceLimits`::`sparseAddressSpaceSize`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkImageCreateInfo structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pImage` must be a valid pointer to a VkImage handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkImageCreateInfo` structure is defined as:

    typedef struct VkImageCreateInfo {
        VkStructureType          sType;
        const void*              pNext;
        VkImageCreateFlags       flags;
        VkImageType              imageType;
        VkFormat                 format;
        VkExtent3D               extent;
        uint32_t                 mipLevels;
        uint32_t                 arrayLayers;
        VkSampleCountFlagBits    samples;
        VkImageTiling            tiling;
        VkImageUsageFlags        usage;
        VkSharingMode            sharingMode;
        uint32_t                 queueFamilyIndexCount;
        const uint32_t*          pQueueFamilyIndices;
        VkImageLayout            initialLayout;
    } VkImageCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkImageCreateFlagBits describing additional parameters of the image.

- `imageType` is a VkImageType value specifying the basic dimensionality of the image. Layers in array textures do not count as a dimension for the purposes of the image type.

- `format` is a VkFormat describing the format and type of the texel blocks that will be contained in the image.

- `extent` is a VkExtent3D describing the number of data elements in each dimension of the base level.

- `mipLevels` describes the number of levels of detail available for minified sampling of the image.

- `arrayLayers` is the number of layers in the image.

- `samples` is a VkSampleCountFlagBits specifying the number of samples per texel.

- `tiling` is a VkImageTiling value specifying the tiling arrangement of the texel blocks in memory.

- `usage` is a bitmask of VkImageUsageFlagBits describing the intended usage of the image.

- `sharingMode` is a VkSharingMode value specifying the sharing mode of the image when it will be accessed by multiple queue families.

- `queueFamilyIndexCount` is the number of entries in the `pQueueFamilyIndices` array.

- `pQueueFamilyIndices` is a list of queue families that will access this image (ignored if `sharingMode` is not `VK_SHARING_MODE_CONCURRENT`).

- `initialLayout` is a VkImageLayout value specifying the initial VkImageLayout of all image subresources of the image. See Image Layouts.

Images created with `tiling` equal to `VK_IMAGE_TILING_LINEAR` have further restrictions on their limits and capabilities compared to images created with `tiling` equal to `VK_IMAGE_TILING_OPTIMAL`. Creation of images with tiling `VK_IMAGE_TILING_LINEAR` may not be supported unless other parameters meet all of the constraints:

- `imageType` is `VK_IMAGE_TYPE_2D`

- `format` is not a depth/stencil format

- `mipLevels` is 1

- `arrayLayers` is 1

- `samples` is `VK_SAMPLE_COUNT_1_BIT`

- `usage` only includes `VK_IMAGE_USAGE_TRANSFER_SRC_BIT` and/or `VK_IMAGE_USAGE_TRANSFER_DST_BIT`

Images created with a `format` from one of those listed in Formats requiring sampler Y′CBCR conversion for `VK_IMAGE_ASPECT_COLOR_BIT` image views have further restrictions on their limits and capabilities compared to images created with other formats. Creation of images with a format requiring Y′CBCR conversion may not be supported unless other parameters meet all of the constraints:

- `imageType` is `VK_IMAGE_TYPE_2D`

- `mipLevels` is 1

- `arrayLayers` is 1

- `samples` is `VK_SAMPLE_COUNT_1_BIT`

Implementations may support additional limits and capabilities beyond those listed above.

To determine the set of valid `usage` bits for a given format, call vkGetPhysicalDeviceFormatProperties.

If the size of the resultant image would exceed `maxResourceSize`, then `vkCreateImage` must fail and return `VK_ERROR_OUT_OF_DEVICE_MEMORY`. This failure may occur even when all image creation parameters satisfy their valid usage requirements.

| Note For images created without `VK_IMAGE_CREATE_EXTENDED_USAGE_BIT` a `usage` bit is valid if it is supported for the format the image is created with. For images created with `VK_IMAGE_CREATE_EXTENDED_USAGE_BIT` a `usage` bit is valid if it is supported for at least one of the formats a `VkImageView` created from the image can have (see Image Views for more detail).

Image Creation Limits

Valid values for some image creation parameters are limited by a numerical upper bound or by inclusion in a bitset. For example, `VkImageCreateInfo`::`arrayLayers` is limited by `imageCreateMaxArrayLayers`, defined below; and `VkImageCreateInfo`::`samples` is limited by `imageCreateSampleCounts`, also defined below.

Several limiting values are defined below, as well as assisting values from which the limiting values are derived. The limiting values are referenced by the relevant valid usage statements of `VkImageCreateInfo`.

- Let `uint64_t imageCreateDrmFormatModifiers[]` be the set of Linux DRM format modifiers that the resultant image may have.

  - If `tiling` is not `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`, then `imageCreateDrmFormatModifiers` is empty.

  - If `VkImageCreateInfo`::`pNext` contains VkImageDrmFormatModifierExplicitCreateInfoEXT, then `imageCreateDrmFormatModifiers` contains exactly one modifier, `VkImageDrmFormatModifierExplicitCreateInfoEXT`::`drmFormatModifier`.

  - If `VkImageCreateInfo`::`pNext` contains VkImageDrmFormatModifierListCreateInfoEXT, then `imageCreateDrmFormatModifiers` contains the exactly the modifiers in `VkImageDrmFormatModifierListCreateInfoEXT`::`pDrmFormatModifiers`.

- Let `VkBool32 imageCreateMaybeLinear` indicate if the resultant image may be linear.

  - If `tiling` is `VK_IMAGE_TILING_LINEAR`, then `imageCreateMaybeLinear` is `true`.

  - If `tiling` is `VK_IMAGE_TILING_OPTIMAL`, then `imageCreateMaybeLinear` is `false`.

  - If `tiling` is `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`, then `imageCreateMaybeLinear_` is `true` if and only if `imageCreateDrmFormatModifiers` contains `DRM_FORMAT_MOD_LINEAR`.

- Let `VkFormatFeatureFlags imageCreateFormatFeatures` be the set of format features available during image creation.

  - If `tiling` is `VK_IMAGE_TILING_LINEAR`, then `imageCreateFormatFeatures` is the value of VkImageFormatProperties::`linearTilingFeatures` found by calling vkGetPhysicalDeviceFormatProperties with parameter `format` equal to `VkImageCreateInfo`::`format`.

  - If `tiling` is `VK_IMAGE_TILING_OPTIMAL`, and if the `pNext` chain includes no VkExternalFormatANDROID structure with non-zero `externalFormat`, then `imageCreateFormatFeatures` is value of VkImageFormatProperties::`optimalTilingFeatures` found by calling vkGetPhysicalDeviceFormatProperties with parameter `format` equal to `VkImageCreateInfo`::`format`.

  - If `tiling` is `VK_IMAGE_TILING_OPTIMAL`, and if the `pNext` chain includes a VkExternalFormatANDROID structure with non-zero `externalFormat`, then `imageCreateFormatFeatures` is the value of VkAndroidHardwareBufferFormatPropertiesANDROID::`formatFeatures` obtained by vkGetAndroidHardwareBufferPropertiesANDROID with a matching `externalFormat` value.

  - If `tiling` is `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`, then the value of `imageCreateFormatFeatures` is found by calling vkGetPhysicalDeviceFormatProperties2 with VkImageFormatProperties::`format` equal to `VkImageCreateInfo`::`format` and with VkDrmFormatModifierPropertiesListEXT chained into VkImageFormatProperties2; by collecting all members of the returned array VkDrmFormatModifierPropertiesListEXT::`pDrmFormatModifierProperties` whose `drmFormatModifier` belongs to `imageCreateDrmFormatModifiers`; and by taking the bitwise intersection, over the collected array members, of `drmFormatModifierTilingFeatures`. (The resultant `imageCreateFormatFeatures` may be empty).

- Let `VkImageFormatProperties2 imageCreateImageFormatPropertiesList[]` be defined as follows.

  - If `VkImageCreateInfo`::`pNext` contains no VkExternalFormatANDROID structure with non-zero `externalFormat`, then `imageCreateImageFormatPropertiesList` is the list of structures obtained by calling vkGetPhysicalDeviceImageFormatProperties2, possibly multiple times, as follows:

    - The parameters VkPhysicalDeviceImageFormatInfo2::`format`, `imageType`, `tiling`, `usage`, and `flags` must be equal to those in `VkImageCreateInfo`.

    - If VkImageCreateInfo::`pNext` contains a VkExternalMemoryImageCreateInfo structure whose `handleTypes` is not `0`, then VkPhysicalDeviceImageFormatInfo2::`pNext` must contain a VkPhysicalDeviceExternalImageFormatInfo structure whose `handleType` is not `0`; and vkGetPhysicalDeviceImageFormatProperties2 must be called for each handle type in VkExternalMemoryImageCreateInfo::`handleTypes`, successively setting VkPhysicalDeviceExternalImageFormatInfo::`handleType` on each call.

    - If VkImageCreateInfo::`pNext` contains no VkExternalMemoryImageCreateInfo structure, or contains a structure whose `handleTypes` is `0`, then VkPhysicalDeviceImageFormatInfo2::`pNext` must either contain no VkPhysicalDeviceExternalImageFormatInfo structure, or contain a structure whose `handleType` is `0`.

    - If `tiling` is `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`, then VkPhysicalDeviceImageFormatInfo2::`pNext` must contain a VkPhysicalDeviceImageDrmFormatModifierInfoEXT structure where `sharingMode` is equal to VkImageCreateInfo::`sharingMode`; and, if `sharingMode` is `VK_SHARING_MODE_CONCURRENT`, then `queueFamilyIndexCount` and `pQueueFamilyIndices` must be equal to those in VkImageCreateInfo; and, if `flags` contains `VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT`, then the VkImageFormatListCreateInfo structure included in the `pNext` chain of VkPhysicalDeviceImageFormatInfo2 must be equivalent to the one included in the `pNext` chain of VkImageCreateInfo; and vkGetPhysicalDeviceImageFormatProperties2 must be called for each modifier in `imageCreateDrmFormatModifiers`, successively setting VkPhysicalDeviceImageDrmFormatModifierInfoEXT::`drmFormatModifier` on each call.

    - If `tiling` is not `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`, then VkPhysicalDeviceImageFormatInfo2::`pNext` must contain no VkPhysicalDeviceImageDrmFormatModifierInfoEXT structure.

    - If any call to vkGetPhysicalDeviceImageFormatProperties2 returns an error, then `imageCreateImageFormatPropertiesList` is defined to be the empty list.

  - If `VkImageCreateInfo`::`pNext` contains a VkExternalFormatANDROID structure with non-zero `externalFormat`, then `imageCreateImageFormatPropertiesList` contains a single element where:

    - `VkImageFormatProperties`::`maxMipLevels` is ⌊log2(max(`extent.width`, `extent.height`, `extent.depth`))⌋ + 1.

    - `VkImageFormatProperties`::`maxArrayLayers` is VkPhysicalDeviceLimits::maxImageArrayLayers.

    - Each component of `VkImageFormatProperties`::`maxExtent` is VkPhysicalDeviceLimits::maxImageDimension2D.

    - `VkImageFormatProperties`::`sampleCounts` contains exactly `VK_SAMPLE_COUNT_1_BIT`.

- Let `uint32_t imageCreateMaxMipLevels` be the minimum value of VkImageFormatProperties::`maxMipLevels` in `imageCreateImageFormatPropertiesList`. The value is undefined if `imageCreateImageFormatPropertiesList` is empty.

- Let `uint32_t imageCreateMaxArrayLayers` be the minimum value of VkImageFormatProperties::`maxArrayLayers` in `imageCreateImageFormatPropertiesList`. The value is undefined if `imageCreateImageFormatPropertiesList` is empty.

- Let `VkExtent3D imageCreateMaxExtent` be the component-wise minimum over all VkImageFormatProperties::`maxExtent` values in `imageCreateImageFormatPropertiesList`. The value is undefined if `imageCreateImageFormatPropertiesList` is empty.

- Let `VkSampleCountFlags imageCreateSampleCounts` be the intersection of each VkImageFormatProperties::`sampleCounts` in `imageCreateImageFormatPropertiesList`. The value is undefined if `imageCreateImageFormatPropertiesList` is empty.

Valid Usage

- Each of the following values (as described in Image Creation Limits) must not be undefined `imageCreateMaxMipLevels`, `imageCreateMaxArrayLayers`, `imageCreateMaxExtent`, and `imageCreateSampleCounts`.

- If `sharingMode` is `VK_SHARING_MODE_CONCURRENT`, `pQueueFamilyIndices` must be a valid pointer to an array of `queueFamilyIndexCount` `uint32_t` values

- If `sharingMode` is `VK_SHARING_MODE_CONCURRENT`, `queueFamilyIndexCount` must be greater than `1`

- If `sharingMode` is `VK_SHARING_MODE_CONCURRENT`, each element of `pQueueFamilyIndices` must be unique and must be less than `pQueueFamilyPropertyCount` returned by either vkGetPhysicalDeviceQueueFamilyProperties or vkGetPhysicalDeviceQueueFamilyProperties2 for the `physicalDevice` that was used to create `device`

- If the `pNext` chain includes a VkExternalFormatANDROID structure, and its `externalFormat` member is non-zero the `format` must be `VK_FORMAT_UNDEFINED`.

- If the `pNext` chain does not include a VkExternalFormatANDROID structure, or does and its `externalFormat` member is `0`, the `format` must not be `VK_FORMAT_UNDEFINED`.

- `extent.width` must be greater than `0`.

- `extent.height` must be greater than `0`.

- `extent.depth` must be greater than `0`.

- `mipLevels` must be greater than `0`

- `arrayLayers` must be greater than `0`

- If `flags` contains `VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT`, `imageType` must be `VK_IMAGE_TYPE_2D`

- If `flags` contains `VK_IMAGE_USAGE_FRAGMENT_DENSITY_MAP_BIT_EXT`, `imageType` must be `VK_IMAGE_TYPE_2D`

- If `flags` contains `VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT`, `imageType` must be `VK_IMAGE_TYPE_3D`

- `extent.width` must be less than or equal to `imageCreateMaxExtent.width` (as defined in Image Creation Limits).

- `extent.height` must be less than or equal to `imageCreateMaxExtent.height` (as defined in Image Creation Limits).

- `extent.depth` must be less than or equal to `imageCreateMaxExtent.depth` (as defined in Image Creation Limits).

- If `imageType` is `VK_IMAGE_TYPE_2D` and `flags` contains `VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT`, `extent.width` and `extent.height` must be equal and `arrayLayers` must be greater than or equal to 6

- If `imageType` is `VK_IMAGE_TYPE_1D`, both `extent.height` and `extent.depth` must be `1`

- If `imageType` is `VK_IMAGE_TYPE_2D`, `extent.depth` must be `1`

- `mipLevels` must be less than or equal to the number of levels in the complete mipmap chain based on `extent.width`, `extent.height`, and `extent.depth`.

- `mipLevels` must be less than or equal to `imageCreateMaxMipLevels` (as defined in Image Creation Limits).

- `arrayLayers` must be less than or equal to `imageCreateMaxArrayLayers` (as defined in Image Creation Limits).

- If `imageType` is `VK_IMAGE_TYPE_3D`, `arrayLayers` must be `1`.

- If `samples` is not `VK_SAMPLE_COUNT_1_BIT`, then `imageType` must be `VK_IMAGE_TYPE_2D`, `flags` must not contain `VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT`, `mipLevels` must be equal to `1`, and `imageCreateMaybeLinear` (as defined in Image Creation Limits) must be `false`,

- If `samples` is not `VK_SAMPLE_COUNT_1_BIT`, `usage` must not contain `VK_IMAGE_USAGE_FRAGMENT_DENSITY_MAP_BIT_EXT`

- If `usage` includes `VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT`, then bits other than `VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT`, `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT`, and `VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT` must not be set

- If `usage` includes `VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT`, `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT`, `VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT`, or `VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT`, `extent.width` must be less than or equal to `VkPhysicalDeviceLimits`::`maxFramebufferWidth`

- If `usage` includes `VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT`, `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT`, `VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT`, or `VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT`, `extent.height` must be less than or equal to `VkPhysicalDeviceLimits`::`maxFramebufferHeight`

- If `usage` includes `VK_IMAGE_USAGE_FRAGMENT_DENSITY_MAP_BIT_EXT`, `extent.width` must be less than or equal to \(\lceil{\frac{maxFramebufferWidth}{minFragmentDensityTexelSize_{width}}}\rceil\)

- If `usage` includes `VK_IMAGE_USAGE_FRAGMENT_DENSITY_MAP_BIT_EXT`, `extent.height` must be less than or equal to \(\lceil{\frac{maxFramebufferHeight}{minFragmentDensityTexelSize_{height}}}\rceil\)

- If `usage` includes `VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT`, `usage` must also contain at least one of `VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT`, `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT`, or `VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT`.

- `samples` must be a bit value that is set in `imageCreateSampleCounts` (as defined in Image Creation Limits).

- If the multisampled storage images feature is not enabled, and `usage` contains `VK_IMAGE_USAGE_STORAGE_BIT`, `samples` must be `VK_SAMPLE_COUNT_1_BIT`

- If the sparse bindings feature is not enabled, `flags` must not contain `VK_IMAGE_CREATE_SPARSE_BINDING_BIT`

- If the sparse aliased residency feature is not enabled, `flags` must not contain `VK_IMAGE_CREATE_SPARSE_ALIASED_BIT`

- If `imageType` is `VK_IMAGE_TYPE_1D`, `flags` must not contain `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`

- If the sparse residency for 2D images feature is not enabled, and `imageType` is `VK_IMAGE_TYPE_2D`, `flags` must not contain `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`

- If the sparse residency for 3D images feature is not enabled, and `imageType` is `VK_IMAGE_TYPE_3D`, `flags` must not contain `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`

- If the sparse residency for images with 2 samples feature is not enabled, `imageType` is `VK_IMAGE_TYPE_2D`, and `samples` is `VK_SAMPLE_COUNT_2_BIT`, `flags` must not contain `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`

- If the sparse residency for images with 4 samples feature is not enabled, `imageType` is `VK_IMAGE_TYPE_2D`, and `samples` is `VK_SAMPLE_COUNT_4_BIT`, `flags` must not contain `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`

- If the sparse residency for images with 8 samples feature is not enabled, `imageType` is `VK_IMAGE_TYPE_2D`, and `samples` is `VK_SAMPLE_COUNT_8_BIT`, `flags` must not contain `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`

- If the sparse residency for images with 16 samples feature is not enabled, `imageType` is `VK_IMAGE_TYPE_2D`, and `samples` is `VK_SAMPLE_COUNT_16_BIT`, `flags` must not contain `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`

- If `flags` contains `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT` or `VK_IMAGE_CREATE_SPARSE_ALIASED_BIT`, it must also contain `VK_IMAGE_CREATE_SPARSE_BINDING_BIT`

- If any of the bits `VK_IMAGE_CREATE_SPARSE_BINDING_BIT`, `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`, or `VK_IMAGE_CREATE_SPARSE_ALIASED_BIT` are set, `VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT` must not also be set

- If the protected memory feature is not enabled, `flags` must not contain `VK_IMAGE_CREATE_PROTECTED_BIT`.

- If any of the bits `VK_IMAGE_CREATE_SPARSE_BINDING_BIT`, `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`, or `VK_IMAGE_CREATE_SPARSE_ALIASED_BIT` are set, `VK_IMAGE_CREATE_PROTECTED_BIT` must not also be set.

- If the `pNext` chain includes a VkExternalMemoryImageCreateInfoNV structure, it must not contain a VkExternalMemoryImageCreateInfo structure.

- If the `pNext` chain includes a VkExternalMemoryImageCreateInfo structure, its `handleTypes` member must only contain bits that are also in VkExternalImageFormatProperties::`externalMemoryProperties.compatibleHandleTypes`, as returned by vkGetPhysicalDeviceImageFormatProperties2 with `format`, `imageType`, `tiling`, `usage`, and `flags` equal to those in this structure, and with a VkPhysicalDeviceExternalImageFormatInfo structure included in the `pNext` chain, with a `handleType` equal to any one of the handle types specified in VkExternalMemoryImageCreateInfo::`handleTypes`

- If the `pNext` chain includes a VkExternalMemoryImageCreateInfoNV structure, its `handleTypes` member must only contain bits that are also in VkExternalImageFormatPropertiesNV::`externalMemoryProperties.compatibleHandleTypes`, as returned by vkGetPhysicalDeviceExternalImageFormatPropertiesNV with `format`, `imageType`, `tiling`, `usage`, and `flags` equal to those in this structure, and with `externalHandleType` equal to any one of the handle types specified in VkExternalMemoryImageCreateInfoNV::`handleTypes`

- If the logical device was created with VkDeviceGroupDeviceCreateInfo::`physicalDeviceCount` equal to 1, `flags` must not contain `VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT`

- If `flags` contains `VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT`, then `mipLevels` must be one, `arrayLayers` must be one, `imageType` must be `VK_IMAGE_TYPE_2D`. and `imageCreateMaybeLinear` (as defined in Image Creation Limits) must be `false`.

- If `flags` contains `VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT`, then `format` must be a block-compressed image format, an ETC compressed image format, or an ASTC compressed image format.

- If `flags` contains `VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT`, then `flags` must also contain `VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT`.

- `initialLayout` must be `VK_IMAGE_LAYOUT_UNDEFINED` or `VK_IMAGE_LAYOUT_PREINITIALIZED`.

- If the `pNext` chain includes a VkExternalMemoryImageCreateInfo or VkExternalMemoryImageCreateInfoNV structure whose `handleTypes` member is not `0`, `initialLayout` must be `VK_IMAGE_LAYOUT_UNDEFINED`

- If the image `format` is one of those listed in Formats requiring sampler Y′CBCR conversion for `VK_IMAGE_ASPECT_COLOR_BIT` image views, then `mipLevels` must be 1

- If the image `format` is one of those listed in Formats requiring sampler Y′CBCR conversion for `VK_IMAGE_ASPECT_COLOR_BIT` image views, `samples` must be `VK_SAMPLE_COUNT_1_BIT`

- If the image `format` is one of those listed in Formats requiring sampler Y′CBCR conversion for `VK_IMAGE_ASPECT_COLOR_BIT` image views, `imageType` must be `VK_IMAGE_TYPE_2D`

- If the image `format` is one of those listed in Formats requiring sampler Y′CBCR conversion for `VK_IMAGE_ASPECT_COLOR_BIT` image views, and the `ycbcrImageArrays` feature is not enabled, `arrayLayers` must be 1

- If `format` is a multi-planar format, and if `imageCreateFormatFeatures` (as defined in Image Creation Limits) does not contain `VK_FORMAT_FEATURE_DISJOINT_BIT`, then `flags` must not contain `VK_IMAGE_CREATE_DISJOINT_BIT`

- If `format` is not a multi-planar format, and `flags` does not include `VK_IMAGE_CREATE_ALIAS_BIT`, `flags` must not contain `VK_IMAGE_CREATE_DISJOINT_BIT`

- If `tiling` is `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`, then the `pNext` chain must include exactly one of VkImageDrmFormatModifierListCreateInfoEXT or VkImageDrmFormatModifierExplicitCreateInfoEXT structures

- If the `pNext` chain includes a VkImageDrmFormatModifierListCreateInfoEXT or VkImageDrmFormatModifierExplicitCreateInfoEXT structure, then `tiling` must be `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`

- If `tiling` is `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT` and `flags` contains `VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT`, then the `pNext` chain must include a VkImageFormatListCreateInfo structure with non-zero `viewFormatCount`.

- If `flags` contains `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT` `format` must be a depth or depth/stencil format

- If the `pNext` chain includes a VkExternalMemoryImageCreateInfo structure whose `handleTypes` member includes `VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID`, `imageType` must be `VK_IMAGE_TYPE_2D`.

- If the `pNext` chain includes a VkExternalMemoryImageCreateInfo structure whose `handleTypes` member includes `VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID`, `mipLevels` must either be `1` or equal to the number of levels in the complete mipmap chain based on `extent.width`, `extent.height`, and `extent.depth`.

- If the `pNext` chain includes a VkExternalFormatANDROID structure whose `externalFormat` member is not `0`, `flags` must not include `VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT`.

- If the `pNext` chain includes a VkExternalFormatANDROID structure whose `externalFormat` member is not `0`, `usage` must not include any usages except `VK_IMAGE_USAGE_SAMPLED_BIT`.

- If the `pNext` chain includes a VkExternalFormatANDROID structure whose `externalFormat` member is not `0`, `tiling` must be `VK_IMAGE_TILING_OPTIMAL`.

- If `format` is a depth-stencil format, `usage` includes `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT`, and the `pNext` chain includes a VkImageStencilUsageCreateInfo structure, then its VkImageStencilUsageCreateInfo::`stencilUsage` member must also include `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT`

- If `format` is a depth-stencil format, `usage` does not include `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT`, and the `pNext` chain includes a VkImageStencilUsageCreateInfo structure, then its VkImageStencilUsageCreateInfo::`stencilUsage` member must also not include `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT`

- If `format` is a depth-stencil format, `usage` includes `VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT`, and the `pNext` chain includes a VkImageStencilUsageCreateInfo structure, then its VkImageStencilUsageCreateInfo::`stencilUsage` member must also include `VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT`

- If `format` is a depth-stencil format, `usage` does not include `VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT`, and the `pNext` chain includes a VkImageStencilUsageCreateInfo structure, then its VkImageStencilUsageCreateInfo::`stencilUsage` member must also not include `VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT`

- If `Format` is a depth-stencil format and the `pNext` chain includes a VkImageStencilUsageCreateInfo structure with its `stencilUsage` member including `VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT`, `extent.width` must be less than or equal to `VkPhysicalDeviceLimits`::`maxFramebufferWidth`

- If `format` is a depth-stencil format and the `pNext` chain includes a VkImageStencilUsageCreateInfo structure with its `stencilUsage` member including `VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT`, `extent.height` must be less than or equal to `VkPhysicalDeviceLimits`::`maxFramebufferHeight`

- If the multisampled storage images feature is not enabled, `format` is a depth-stencil format and the `pNext` chain includes a VkImageStencilUsageCreateInfo structure with its `stencilUsage` including `VK_IMAGE_USAGE_STORAGE_BIT`, `samples` must be `VK_SAMPLE_COUNT_1_BIT`

- If `flags` contains `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV`, `imageType` must be `VK_IMAGE_TYPE_2D` or `VK_IMAGE_TYPE_3D`

- If `flags` contains `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV`, it must not contain `VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT` and the `format` must not be a depth/stencil format

- If `flags` contains `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV` and `imageType` is `VK_IMAGE_TYPE_2D`, `extent.width` and `extent.height` must be greater than `1`

- If `flags` contains `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV` and `imageType` is `VK_IMAGE_TYPE_3D`, `extent.width`, `extent.height`, and `extent.depth` must be greater than `1`

- If `usage` includes `VK_IMAGE_USAGE_SHADING_RATE_IMAGE_BIT_NV`, `imageType` must be `VK_IMAGE_TYPE_2D`.

- If `usage` includes `VK_IMAGE_USAGE_SHADING_RATE_IMAGE_BIT_NV`, `samples` must be `VK_SAMPLE_COUNT_1_BIT`.

- If `usage` includes `VK_IMAGE_USAGE_SHADING_RATE_IMAGE_BIT_NV`, `tiling` must be `VK_IMAGE_TILING_OPTIMAL`.

- If `flags` contains `VK_IMAGE_CREATE_SUBSAMPLED_BIT_EXT`, `tiling` must be `VK_IMAGE_TILING_OPTIMAL`

- If `flags` contains `VK_IMAGE_CREATE_SUBSAMPLED_BIT_EXT`, `imageType` must be `VK_IMAGE_TYPE_2D`

- If `flags` contains `VK_IMAGE_CREATE_SUBSAMPLED_BIT_EXT`, `flags` must not contain `VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT`

- If `flags` contains `VK_IMAGE_CREATE_SUBSAMPLED_BIT_EXT`, `mipLevels` must be `1`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkDedicatedAllocationImageCreateInfoNV, VkExternalFormatANDROID, VkExternalMemoryImageCreateInfo, VkExternalMemoryImageCreateInfoNV, VkImageDrmFormatModifierExplicitCreateInfoEXT, VkImageDrmFormatModifierListCreateInfoEXT, VkImageFormatListCreateInfo, VkImageStencilUsageCreateInfo, or VkImageSwapchainCreateInfoKHR

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be a valid combination of VkImageCreateFlagBits values

- `imageType` must be a valid VkImageType value

- `format` must be a valid VkFormat value

- `samples` must be a valid VkSampleCountFlagBits value

- `tiling` must be a valid VkImageTiling value

- `usage` must be a valid combination of VkImageUsageFlagBits values

- `usage` must not be `0`

- `sharingMode` must be a valid VkSharingMode value

- `initialLayout` must be a valid VkImageLayout value

The `VkImageStencilUsageCreateInfo` structure is defined as:

    typedef struct VkImageStencilUsageCreateInfo {
        VkStructureType      sType;
        const void*          pNext;
        VkImageUsageFlags    stencilUsage;
    } VkImageStencilUsageCreateInfo;

or the equivalent

    typedef VkImageStencilUsageCreateInfo VkImageStencilUsageCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `stencilUsage` is a bitmask of VkImageUsageFlagBits describing the intended usage of the stencil aspect of the image.

If the `pNext` chain of VkImageCreateInfo includes a `VkImageStencilUsageCreateInfo` structure, then that structure includes the usage flags specific to the stencil aspect of the image for an image with a depth-stencil format.

This structure specifies image usages which only apply to the stencil aspect of a depth/stencil format image. When this structure is included in the `pNext` chain of VkImageCreateInfo, the stencil aspect of the image must only be used as specified by `stencilUsage`. When this structure is not included in the `pNext` chain of VkImageCreateInfo, the stencil aspect of an image must only be used as specified VkImageCreateInfo::`usage`. Use of other aspects of an image are unaffected by this structure.

This structure can also be included in the `pNext` chain of VkPhysicalDeviceImageFormatInfo2 to query additional capabilities specific to image creation parameter combinations including a separate set of usage flags for the stencil aspect of the image using vkGetPhysicalDeviceImageFormatProperties2. When this structure is not included in the `pNext` chain of `VkPhysicalDeviceImageFormatInfo2` then the implicit value of `stencilUsage` matches that of `VkPhysicalDeviceImageFormatInfo2`::`usage`.

Valid Usage

- If `stencilUsage` includes `VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT`, it must not include bits other than `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT` or `VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMAGE_STENCIL_USAGE_CREATE_INFO`

- `stencilUsage` must be a valid combination of VkImageUsageFlagBits values

- `stencilUsage` must not be `0`

If the `pNext` chain includes a `VkDedicatedAllocationImageCreateInfoNV` structure, then that structure includes an enable controlling whether the image will have a dedicated memory allocation bound to it.

The `VkDedicatedAllocationImageCreateInfoNV` structure is defined as:

    typedef struct VkDedicatedAllocationImageCreateInfoNV {
        VkStructureType    sType;
        const void*        pNext;
        VkBool32           dedicatedAllocation;
    } VkDedicatedAllocationImageCreateInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `dedicatedAllocation` specifies whether the image will have a dedicated allocation bound to it.

| Note Using a dedicated allocation for color and depth/stencil attachments or other large images may improve performance on some devices.

Valid Usage

- If `dedicatedAllocation` is `VK_TRUE`, `VkImageCreateInfo`::`flags` must not include `VK_IMAGE_CREATE_SPARSE_BINDING_BIT`, `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`, or `VK_IMAGE_CREATE_SPARSE_ALIASED_BIT`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_IMAGE_CREATE_INFO_NV`

To define a set of external memory handle types that may be used as backing store for an image, add a VkExternalMemoryImageCreateInfo structure to the `pNext` chain of the VkImageCreateInfo structure. The `VkExternalMemoryImageCreateInfo` structure is defined as:

    typedef struct VkExternalMemoryImageCreateInfo {
        VkStructureType                    sType;
        const void*                        pNext;
        VkExternalMemoryHandleTypeFlags    handleTypes;
    } VkExternalMemoryImageCreateInfo;

or the equivalent

    typedef VkExternalMemoryImageCreateInfo VkExternalMemoryImageCreateInfoKHR;

| Note A `VkExternalMemoryImageCreateInfo` structure must be included in the creation parameters for an image that will be bound to memory that is either exported or imported.

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `handleTypes` is a bitmask of VkExternalMemoryHandleTypeFlagBits specifying one or more external memory handle types.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_IMAGE_CREATE_INFO`

- `handleTypes` must be a valid combination of VkExternalMemoryHandleTypeFlagBits values

- `handleTypes` must not be `0`

If the `pNext` chain includes a `VkExternalMemoryImageCreateInfoNV` structure, then that structure defines a set of external memory handle types that may be used as backing store for the image.

The `VkExternalMemoryImageCreateInfoNV` structure is defined as:

    typedef struct VkExternalMemoryImageCreateInfoNV {
        VkStructureType                      sType;
        const void*                          pNext;
        VkExternalMemoryHandleTypeFlagsNV    handleTypes;
    } VkExternalMemoryImageCreateInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `handleTypes` is a bitmask of VkExternalMemoryHandleTypeFlagBitsNV specifying one or more external memory handle types.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_IMAGE_CREATE_INFO_NV`

- `handleTypes` must be a valid combination of VkExternalMemoryHandleTypeFlagBitsNV values

To create an image with an external format, add a `VkExternalFormatANDROID` structure in the `pNext` chain of VkImageCreateInfo. `VkExternalFormatANDROID` is defined as:

    typedef struct VkExternalFormatANDROID {
        VkStructureType    sType;
        void*              pNext;
        uint64_t           externalFormat;
    } VkExternalFormatANDROID;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `externalFormat` is an implementation-defined identifier for the external format

If `externalFormat` is zero, the effect is as if the `VkExternalFormatANDROID` structure was not present. Otherwise, the `image` will have the specified external format.

Valid Usage

- `externalFormat` must be `0` or a value returned in the `externalFormat` member of VkAndroidHardwareBufferFormatPropertiesANDROID by an earlier call to vkGetAndroidHardwareBufferPropertiesANDROID

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_EXTERNAL_FORMAT_ANDROID`

If the `pNext` chain of VkImageCreateInfo includes a `VkImageSwapchainCreateInfoKHR` structure, then that structure includes a swapchain handle indicating that the image will be bound to memory from that swapchain.

The `VkImageSwapchainCreateInfoKHR` structure is defined as:

    typedef struct VkImageSwapchainCreateInfoKHR {
        VkStructureType    sType;
        const void*        pNext;
        VkSwapchainKHR     swapchain;
    } VkImageSwapchainCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `swapchain` is VK_NULL_HANDLE or a handle of a swapchain that the image will be bound to.

Valid Usage

- If `swapchain` is not VK_NULL_HANDLE, the fields of VkImageCreateInfo must match the implied image creation parameters of the swapchain

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMAGE_SWAPCHAIN_CREATE_INFO_KHR`

- If `swapchain` is not VK_NULL_HANDLE, `swapchain` must be a valid VkSwapchainKHR handle

If the `pNext` list of VkImageCreateInfo includes a `VkImageFormatListCreateInfo` structure, then that structure contains a list of all formats that can be used when creating views of this image.

The `VkImageFormatListCreateInfo` structure is defined as:

    typedef struct VkImageFormatListCreateInfo {
        VkStructureType    sType;
        const void*        pNext;
        uint32_t           viewFormatCount;
        const VkFormat*    pViewFormats;
    } VkImageFormatListCreateInfo;

or the equivalent

    typedef VkImageFormatListCreateInfo VkImageFormatListCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `viewFormatCount` is the number of entries in the `pViewFormats` array.

- `pViewFormats` is an array which lists of all formats which can be used when creating views of this image.

If `viewFormatCount` is zero, `pViewFormats` is ignored and the image is created as if the `VkImageFormatListCreateInfo` structure were not included in the `pNext` list of VkImageCreateInfo.

Valid Usage

- If `viewFormatCount` is not `0`, all of the formats in the `pViewFormats` array must be compatible with the format specified in the `format` field of `VkImageCreateInfo`, as described in the compatibility table.

- If `VkImageCreateInfo`::`flags` does not contain `VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT`, `viewFormatCount` must be `0` or `1`.

- If `viewFormatCount` is not `0`, `VkImageCreateInfo`::`format` must be in `pViewFormats`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMAGE_FORMAT_LIST_CREATE_INFO`

- If `viewFormatCount` is not `0`, `pViewFormats` must be a valid pointer to an array of `viewFormatCount` valid VkFormat values

If the `pNext` chain of VkImageCreateInfo includes a VkImageDrmFormatModifierListCreateInfoEXT structure, then the image will be created with one of the Linux DRM format modifiers listed in the structure. The choice of modifier is implementation-dependent.

The VkImageDrmFormatModifierListCreateInfoEXT structure is defined as:

    typedef struct VkImageDrmFormatModifierListCreateInfoEXT {
        VkStructureType    sType;
        const void*        pNext;
        uint32_t           drmFormatModifierCount;
        const uint64_t*    pDrmFormatModifiers;
    } VkImageDrmFormatModifierListCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `drmFormatModifierCount` is the length of the `pDrmFormatModifiers` array.

- `pDrmFormatModifiers` is a pointer to an array of Linux DRM format modifiers.

Valid Usage

- Each modifier in `pDrmFormatModifiers` must be compatible with the parameters in VkImageCreateInfo and its `pNext` chain, as determined by querying VkPhysicalDeviceImageFormatInfo2 extended with VkPhysicalDeviceImageDrmFormatModifierInfoEXT.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMAGE_DRM_FORMAT_MODIFIER_LIST_CREATE_INFO_EXT`

- `pDrmFormatModifiers` must be a valid pointer to an array of `drmFormatModifierCount` `uint64_t` values

- `drmFormatModifierCount` must be greater than `0`

If the `pNext` chain of VkImageCreateInfo includes a VkImageDrmFormatModifierExplicitCreateInfoEXT structure, then the image will be created with the Linux DRM format modifier and memory layout defined by the structure.

The VkImageDrmFormatModifierExplicitCreateInfoEXT structure is defined as:

    typedef struct VkImageDrmFormatModifierExplicitCreateInfoEXT {
        VkStructureType               sType;
        const void*                   pNext;
        uint64_t                      drmFormatModifier;
        uint32_t                      drmFormatModifierPlaneCount;
        const VkSubresourceLayout*    pPlaneLayouts;
    } VkImageDrmFormatModifierExplicitCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `drmFormatModifier` is the Linux DRM format modifier with which the image will be created.

- `drmFormatModifierPlaneCount` is the number of memory planes in the image (as reported by VkDrmFormatModifierPropertiesEXT) as well as the length of the `pPlaneLayouts` array.

- `pPlaneLayouts` is a pointer to an array of VkSubresourceLayout structures describing the image’s memory planes.

The `i`th member of `pPlaneLayouts` describes the layout of the image’s `i`th memory plane (that is, `VK_IMAGE_ASPECT_MEMORY_PLANE_i_BIT_EXT`). In each element of `pPlaneLayouts`, the implementation must ignore `size`. The implementation calculates the size of each plane, which the application can query with vkGetImageSubresourceLayout.

When creating an image with VkImageDrmFormatModifierExplicitCreateInfoEXT, it is the application’s responsibility to satisfy all valid usage requirements. However, the implementation must validate that the provided `pPlaneLayouts`, when combined with the provided `drmFormatModifier` and other creation parameters in VkImageCreateInfo and its `pNext` chain, produce a valid image. (This validation is necessarily implementation-dependent and outside the scope of Vulkan, and therefore not described by valid usage requirements). If this validation fails, then vkCreateImage returns `VK_ERROR_INVALID_DRM_FORMAT_MODIFIER_PLANE_LAYOUT_EXT`.

Valid Usage

- `drmFormatModifier` must be compatible with the parameters in VkImageCreateInfo and its `pNext` chain, as determined by querying VkPhysicalDeviceImageFormatInfo2 extended with VkPhysicalDeviceImageDrmFormatModifierInfoEXT.

- `drmFormatModifierPlaneCount` must be equal to the VkDrmFormatModifierPropertiesEXT::`drmFormatModifierPlaneCount` associated with VkImageCreateInfo::`format` and `drmFormatModifier`, as found by querying VkDrmFormatModifierPropertiesListEXT.

- For each element of `pPlaneLayouts`, `size` must be 0

- For each element of `pPlaneLayouts`, `arrayPitch` must be 0 if VkImageCreateInfo::`arrayLayers` is 1.

- For each element of `pPlaneLayouts`, `depthPitch` must be 0 if VkImageCreateInfo::`extent.depth` is 1.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMAGE_DRM_FORMAT_MODIFIER_EXPLICIT_CREATE_INFO_EXT`

- If `drmFormatModifierPlaneCount` is not `0`, `pPlaneLayouts` must be a valid pointer to an array of `drmFormatModifierPlaneCount` VkSubresourceLayout structures

Bits which can be set in VkImageCreateInfo::`usage`, specifying intended usage of an image, are:

    typedef enum VkImageUsageFlagBits {
        VK_IMAGE_USAGE_TRANSFER_SRC_BIT = 0x00000001,
        VK_IMAGE_USAGE_TRANSFER_DST_BIT = 0x00000002,
        VK_IMAGE_USAGE_SAMPLED_BIT = 0x00000004,
        VK_IMAGE_USAGE_STORAGE_BIT = 0x00000008,
        VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT = 0x00000010,
        VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT = 0x00000020,
        VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT = 0x00000040,
        VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT = 0x00000080,
        VK_IMAGE_USAGE_SHADING_RATE_IMAGE_BIT_NV = 0x00000100,
        VK_IMAGE_USAGE_FRAGMENT_DENSITY_MAP_BIT_EXT = 0x00000200,
        VK_IMAGE_USAGE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkImageUsageFlagBits;

- `VK_IMAGE_USAGE_TRANSFER_SRC_BIT` specifies that the image can be used as the source of a transfer command.

- `VK_IMAGE_USAGE_TRANSFER_DST_BIT` specifies that the image can be used as the destination of a transfer command.

- `VK_IMAGE_USAGE_SAMPLED_BIT` specifies that the image can be used to create a `VkImageView` suitable for occupying a `VkDescriptorSet` slot either of type `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE` or `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, and be sampled by a shader.

- `VK_IMAGE_USAGE_STORAGE_BIT` specifies that the image can be used to create a `VkImageView` suitable for occupying a `VkDescriptorSet` slot of type `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE`.

- `VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT` specifies that the image can be used to create a `VkImageView` suitable for use as a color or resolve attachment in a `VkFramebuffer`.

- `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT` specifies that the image can be used to create a `VkImageView` suitable for use as a depth/stencil or depth/stencil resolve attachment in a `VkFramebuffer`.

- `VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT` specifies that the memory bound to this image will have been allocated with the `VK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BIT` (see Memory Allocation for more detail). This bit can be set for any image that can be used to create a `VkImageView` suitable for use as a color, resolve, depth/stencil, or input attachment.

- `VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT` specifies that the image can be used to create a `VkImageView` suitable for occupying `VkDescriptorSet` slot of type `VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT`; be read from a shader as an input attachment; and be used as an input attachment in a framebuffer.

- `VK_IMAGE_USAGE_SHADING_RATE_IMAGE_BIT_NV` specifies that the image can be used to create a `VkImageView` suitable for use as a shading rate image.

- `VK_IMAGE_USAGE_FRAGMENT_DENSITY_MAP_BIT_EXT` specifies that the image can be used to create a `VkImageView` suitable for use as a fragment density map image.

    typedef VkFlags VkImageUsageFlags;

`VkImageUsageFlags` is a bitmask type for setting a mask of zero or more VkImageUsageFlagBits.

Bits which can be set in VkImageCreateInfo::`flags`, specifying additional parameters of an image, are:

    typedef enum VkImageCreateFlagBits {
        VK_IMAGE_CREATE_SPARSE_BINDING_BIT = 0x00000001,
        VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT = 0x00000002,
        VK_IMAGE_CREATE_SPARSE_ALIASED_BIT = 0x00000004,
        VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT = 0x00000008,
        VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT = 0x00000010,
        VK_IMAGE_CREATE_ALIAS_BIT = 0x00000400,
        VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT = 0x00000040,
        VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT = 0x00000020,
        VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT = 0x00000080,
        VK_IMAGE_CREATE_EXTENDED_USAGE_BIT = 0x00000100,
        VK_IMAGE_CREATE_PROTECTED_BIT = 0x00000800,
        VK_IMAGE_CREATE_DISJOINT_BIT = 0x00000200,
        VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV = 0x00002000,
        VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT = 0x00001000,
        VK_IMAGE_CREATE_SUBSAMPLED_BIT_EXT = 0x00004000,
        VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT_KHR = VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT,
        VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT_KHR = VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT,
        VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT_KHR = VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT,
        VK_IMAGE_CREATE_EXTENDED_USAGE_BIT_KHR = VK_IMAGE_CREATE_EXTENDED_USAGE_BIT,
        VK_IMAGE_CREATE_DISJOINT_BIT_KHR = VK_IMAGE_CREATE_DISJOINT_BIT,
        VK_IMAGE_CREATE_ALIAS_BIT_KHR = VK_IMAGE_CREATE_ALIAS_BIT,
        VK_IMAGE_CREATE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkImageCreateFlagBits;

- `VK_IMAGE_CREATE_SPARSE_BINDING_BIT` specifies that the image will be backed using sparse memory binding.

- `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT` specifies that the image can be partially backed using sparse memory binding. Images created with this flag must also be created with the `VK_IMAGE_CREATE_SPARSE_BINDING_BIT` flag.

- `VK_IMAGE_CREATE_SPARSE_ALIASED_BIT` specifies that the image will be backed using sparse memory binding with memory ranges that might also simultaneously be backing another image (or another portion of the same image). Images created with this flag must also be created with the `VK_IMAGE_CREATE_SPARSE_BINDING_BIT` flag

- `VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT` specifies that the image can be used to create a `VkImageView` with a different format from the image. For multi-planar formats, `VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT` specifies that a `VkImageView` can be created of a plane of the image.

- `VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT` specifies that the image can be used to create a `VkImageView` of type `VK_IMAGE_VIEW_TYPE_CUBE` or `VK_IMAGE_VIEW_TYPE_CUBE_ARRAY`.

- `VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT` specifies that the image can be used to create a `VkImageView` of type `VK_IMAGE_VIEW_TYPE_2D` or `VK_IMAGE_VIEW_TYPE_2D_ARRAY`.

- `VK_IMAGE_CREATE_PROTECTED_BIT` specifies that the image is a protected image.

- `VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT` specifies that the image can be used with a non-zero value of the `splitInstanceBindRegionCount` member of a VkBindImageMemoryDeviceGroupInfo structure passed into vkBindImageMemory2. This flag also has the effect of making the image use the standard sparse image block dimensions.

- `VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT` specifies that the image having a compressed format can be used to create a `VkImageView` with an uncompressed format where each texel in the image view corresponds to a compressed texel block of the image.

- `VK_IMAGE_CREATE_EXTENDED_USAGE_BIT` specifies that the image can be created with usage flags that are not supported for the format the image is created with but are supported for at least one format a `VkImageView` created from the image can have.

- `VK_IMAGE_CREATE_DISJOINT_BIT` specifies that an image with a multi-planar format must have each plane separately bound to memory, rather than having a single memory binding for the whole image; the presence of this bit distinguishes a disjoint image from an image without this bit set.

- `VK_IMAGE_CREATE_ALIAS_BIT` specifies that two images created with the same creation parameters and aliased to the same memory can interpret the contents of the memory consistently with each other, subject to the rules described in the Memory Aliasing section. This flag further specifies that each plane of a disjoint image can share an in-memory non-linear representation with single-plane images, and that a single-plane image can share an in-memory non-linear representation with a plane of a multi-planar disjoint image, according to the rules in Compatible formats of planes of multi-planar formats. If the `pNext` chain includes a VkExternalMemoryImageCreateInfo or VkExternalMemoryImageCreateInfoNV structure whose `handleTypes` member is not `0`, it is as if `VK_IMAGE_CREATE_ALIAS_BIT` is set.

- `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT` specifies that an image with a depth or depth/stencil format can be used with custom sample locations when used as a depth/stencil attachment.

- `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV` specifies that the image is a corner-sampled image.

- `VK_IMAGE_CREATE_SUBSAMPLED_BIT_EXT` specifies that an image can be in a subsampled format which may be more optimal when written as an attachment by a render pass that has a fragment density map attachment. Accessing a subsampled image has additional considerations:

  - Image data read as an image sampler is undefined if the sampler was not created with `flags` containing `VK_SAMPLER_CREATE_SUBSAMPLED_BIT_EXT` or was not sampled through the use of a combined image sampler with an immutable sampler in `VkDescriptorSetLayoutBinding`.

  - Image data read with an input attachment is undefined if the contents were not written as an attachment in an earlier subpass of the same render pass.

  - Image data read with load operations may be resampled to the fragment density of the render pass.

  - Image contents outside of the render area become undefined if the image is stored as a render pass attachment.

See Sparse Resource Features and Sparse Physical Device Features for more details.

    typedef VkFlags VkImageCreateFlags;

`VkImageCreateFlags` is a bitmask type for setting a mask of zero or more VkImageCreateFlagBits.

Possible values of VkImageCreateInfo::`imageType`, specifying the basic dimensionality of an image, are:

    typedef enum VkImageType {
        VK_IMAGE_TYPE_1D = 0,
        VK_IMAGE_TYPE_2D = 1,
        VK_IMAGE_TYPE_3D = 2,
        VK_IMAGE_TYPE_MAX_ENUM = 0x7FFFFFFF
    } VkImageType;

- `VK_IMAGE_TYPE_1D` specifies a one-dimensional image.

- `VK_IMAGE_TYPE_2D` specifies a two-dimensional image.

- `VK_IMAGE_TYPE_3D` specifies a three-dimensional image.

Possible values of VkImageCreateInfo::`tiling`, specifying the tiling arrangement of texel blocks in an image, are:

    typedef enum VkImageTiling {
        VK_IMAGE_TILING_OPTIMAL = 0,
        VK_IMAGE_TILING_LINEAR = 1,
        VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT = 1000158000,
        VK_IMAGE_TILING_MAX_ENUM = 0x7FFFFFFF
    } VkImageTiling;

- `VK_IMAGE_TILING_OPTIMAL` specifies optimal tiling (texels are laid out in an implementation-dependent arrangement, for more optimal memory access).

- `VK_IMAGE_TILING_LINEAR` specifies linear tiling (texels are laid out in memory in row-major order, possibly with some padding on each row).

- `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT` indicates that the image’s tiling is defined by a Linux DRM format modifier. The modifier is specified at image creation with VkImageDrmFormatModifierListCreateInfoEXT or VkImageDrmFormatModifierExplicitCreateInfoEXT, and can be queried with vkGetImageDrmFormatModifierPropertiesEXT.

To query the memory layout of an image subresource, call:

    void vkGetImageSubresourceLayout(
        VkDevice                                    device,
        VkImage                                     image,
        const VkImageSubresource*                   pSubresource,
        VkSubresourceLayout*                        pLayout);

- `device` is the logical device that owns the image.

- `image` is the image whose layout is being queried.

- `pSubresource` is a pointer to a VkImageSubresource structure selecting a specific image for the image subresource.

- `pLayout` is a pointer to a VkSubresourceLayout structure in which the layout is returned.

If the image is linear, then the returned layout is valid for host access.

If the image’s tiling is `VK_IMAGE_TILING_LINEAR` and its format is a multi-planar format, then `vkGetImageSubresourceLayout` describes one format plane of the image. If the image’s tiling is `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`, then `vkGetImageSubresourceLayout` describes one memory plane of the image. If the image’s tiling is `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT` and the image is non-linear, then the returned layout has an implementation-dependent meaning; the vendor of the image’s DRM format modifier may provide documentation that explains how to interpret the returned layout.

`vkGetImageSubresourceLayout` is invariant for the lifetime of a single image. However, the subresource layout of images in Android hardware buffer external memory is not known until the image has been bound to memory, so applications must not call vkGetImageSubresourceLayout for such an image before it has been bound.

Valid Usage

- `image` must have been created with `tiling` equal to `VK_IMAGE_TILING_LINEAR` or `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`

- The `aspectMask` member of `pSubresource` must only have a single bit set

- The `mipLevel` member of `pSubresource` must be less than the `mipLevels` specified in VkImageCreateInfo when `image` was created

- The `arrayLayer` member of `pSubresource` must be less than the `arrayLayers` specified in VkImageCreateInfo when `image` was created

- If the `tiling` of the `image` is `VK_IMAGE_TILING_LINEAR` and its `format` is a multi-planar format with two planes, the `aspectMask` member of `pSubresource` must be `VK_IMAGE_ASPECT_PLANE_0_BIT` or `VK_IMAGE_ASPECT_PLANE_1_BIT`

- If the `tiling` of the `image` is `VK_IMAGE_TILING_LINEAR` and its `format` is a multi-planar format with three planes, the `aspectMask` member of `pSubresource` must be `VK_IMAGE_ASPECT_PLANE_0_BIT`, `VK_IMAGE_ASPECT_PLANE_1_BIT` or `VK_IMAGE_ASPECT_PLANE_2_BIT`

- If `image` was created with the `VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID` external memory handle type, then `image` must be bound to memory.

- If the `tiling` of the `image` is `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`, then the `aspectMask` member of `pSubresource` must be `VK_IMAGE_ASPECT_MEMORY_PLANE_i_BIT_EXT` and the index `i` must be less than the `drmFormatModifierPlaneCount` associated with the image’s `format` and `drmFormatModifier`.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `image` must be a valid VkImage handle

- `pSubresource` must be a valid pointer to a valid VkImageSubresource structure

- `pLayout` must be a valid pointer to a VkSubresourceLayout structure

- `image` must have been created, allocated, or retrieved from `device`

The `VkImageSubresource` structure is defined as:

    typedef struct VkImageSubresource {
        VkImageAspectFlags    aspectMask;
        uint32_t              mipLevel;
        uint32_t              arrayLayer;
    } VkImageSubresource;

- `aspectMask` is a VkImageAspectFlags selecting the image aspect.

- `mipLevel` selects the mipmap level.

- `arrayLayer` selects the array layer.

Valid Usage (Implicit)

- `aspectMask` must be a valid combination of VkImageAspectFlagBits values

- `aspectMask` must not be `0`

Information about the layout of the image subresource is returned in a `VkSubresourceLayout` structure:

    typedef struct VkSubresourceLayout {
        VkDeviceSize    offset;
        VkDeviceSize    size;
        VkDeviceSize    rowPitch;
        VkDeviceSize    arrayPitch;
        VkDeviceSize    depthPitch;
    } VkSubresourceLayout;

- `offset` is the byte offset from the start of the image or the plane where the image subresource begins.

- `size` is the size in bytes of the image subresource. `size` includes any extra memory that is required based on `rowPitch`.

- `rowPitch` describes the number of bytes between each row of texels in an image.

- `arrayPitch` describes the number of bytes between each array layer of an image.

- `depthPitch` describes the number of bytes between each slice of 3D image.

If the image is linear, then `rowPitch`, `arrayPitch` and `depthPitch` describe the layout of the image subresource in linear memory. For uncompressed formats, `rowPitch` is the number of bytes between texels with the same x coordinate in adjacent rows (y coordinates differ by one). `arrayPitch` is the number of bytes between texels with the same x and y coordinate in adjacent array layers of the image (array layer values differ by one). `depthPitch` is the number of bytes between texels with the same x and y coordinate in adjacent slices of a 3D image (z coordinates differ by one). Expressed as an addressing formula, the starting byte of a texel in the image subresource has address:

    // (x,y,z,layer) are in texel coordinates
    address(x,y,z,layer) = layer*arrayPitch + z*depthPitch + y*rowPitch + x*elementSize + offset

For compressed formats, the `rowPitch` is the number of bytes between compressed texel blocks in adjacent rows. `arrayPitch` is the number of bytes between compressed texel blocks in adjacent array layers. `depthPitch` is the number of bytes between compressed texel blocks in adjacent slices of a 3D image.

    // (x,y,z,layer) are in compressed texel block coordinates
    address(x,y,z,layer) = layer*arrayPitch + z*depthPitch + y*rowPitch + x*compressedTexelBlockByteSize + offset;

The value of `arrayPitch` is undefined for images that were not created as arrays. `depthPitch` is defined only for 3D images.

If the image has a single-plane color format and its tiling is `VK_IMAGE_TILING_LINEAR` , then the `aspectMask` member of `VkImageSubresource` must be `VK_IMAGE_ASPECT_COLOR_BIT`.

If the image has a depth/stencil format and its tiling is `VK_IMAGE_TILING_LINEAR` , then `aspectMask` must be either `VK_IMAGE_ASPECT_DEPTH_BIT` or `VK_IMAGE_ASPECT_STENCIL_BIT`. On implementations that store depth and stencil aspects separately, querying each of these image subresource layouts will return a different `offset` and `size` representing the region of memory used for that aspect. On implementations that store depth and stencil aspects interleaved, the same `offset` and `size` are returned and represent the interleaved memory allocation.

If the image has a multi-planar format and its tiling is `VK_IMAGE_TILING_LINEAR` , then the `aspectMask` member of `VkImageSubresource` must be `VK_IMAGE_ASPECT_PLANE_0_BIT`, `VK_IMAGE_ASPECT_PLANE_1_BIT`, or (for 3-plane formats only) `VK_IMAGE_ASPECT_PLANE_2_BIT`. Querying each of these image subresource layouts will return a different `offset` and `size` representing the region of memory used for that plane. If the image is disjoint, then the `offset` is relative to the base address of the plane. If the image is non-disjoint, then the `offset` is relative to the base address of the image.

If the image’s tiling is `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`, then the `aspectMask` member of `VkImageSubresource` must be one of `VK_IMAGE_ASPECT_MEMORY_PLANE_i_BIT_EXT`, where the maximum allowed plane index `i` is defined by the `drmFormatModifierPlaneCount` associated with the image’s `format` and modifier. The memory range used by the subresource is described by `offset` and `size`. If the image is disjoint, then the `offset` is relative to the base address of the memory plane. If the image is non-disjoint, then the `offset` is relative to the base address of the image. If the image is non-linear, then `rowPitch`, `arrayPitch`, and `depthPitch` have an implementation-dependent meaning.

If an image was created with `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`, then the image has a Linux DRM format modifier. To query the modifier, call:

    VkResult vkGetImageDrmFormatModifierPropertiesEXT(
        VkDevice                                    device,
        VkImage                                     image,
        VkImageDrmFormatModifierPropertiesEXT*      pProperties);

- `device` is the logical device that owns the image.

- `image` is the queried image.

- `pProperties` will return properties of the image’s DRM format modifier.

Valid Usage

- `image` must have been created with `tiling` equal to `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `image` must be a valid VkImage handle

- `pProperties` must be a valid pointer to a VkImageDrmFormatModifierPropertiesEXT structure

- `image` must have been created, allocated, or retrieved from `device`

Return Codes

Success

  - `VK_SUCCESS`

The VkImageDrmFormatModifierPropertiesEXT structure is defined as:

    typedef struct VkImageDrmFormatModifierPropertiesEXT {
        VkStructureType    sType;
        void*              pNext;
        uint64_t           drmFormatModifier;
    } VkImageDrmFormatModifierPropertiesEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `drmFormatModifier` returns the image’s Linux DRM format modifier.

If the `image` was created with VkImageDrmFormatModifierListCreateInfoEXT, then the returned `drmFormatModifier` must belong to the list of modifiers provided at time of image creation in VkImageDrmFormatModifierListCreateInfoEXT::`pDrmFormatModifiers`. If the `image` was created with VkImageDrmFormatModifierExplicitCreateInfoEXT, then the returned `drmFormatModifier` must be the modifier provided at time of image creation in VkImageDrmFormatModifierExplicitCreateInfoEXT::`drmFormatModifier`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMAGE_DRM_FORMAT_MODIFIER_PROPERTIES_EXT`

- `pNext` must be `NULL`

To destroy an image, call:

    void vkDestroyImage(
        VkDevice                                    device,
        VkImage                                     image,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that destroys the image.

- `image` is the image to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage

- All submitted commands that refer to `image`, either directly or via a `VkImageView`, must have completed execution

- If `VkAllocationCallbacks` were provided when `image` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `image` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `image` is not VK_NULL_HANDLE, `image` must be a valid VkImage handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- If `image` is a valid handle, it must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `image` must be externally synchronized

#### 11.3.1. Image Format Features

Valid usage of a VkImage may be constrained by the image’s format features, defined below. Such constraints are documented in the affected valid usage statement.

- If the image was created with `VK_IMAGE_TILING_LINEAR`, then its set of format features is the value of VkFormatProperties::`linearTilingFeatures` found by calling vkGetPhysicalDeviceFormatProperties on the same `format` as VkImageCreateInfo::`format`.

- If the image was created with `VK_IMAGE_TILING_OPTIMAL`, but without an external format, then its set of format features is the value of VkFormatProperties::`optimalTilingFeatures` found by calling vkGetPhysicalDeviceFormatProperties on the same `format` as VkImageCreateInfo::`format`.

- If the image was created with an external format, then its set of format features is the value of VkAndroidHardwareBufferFormatPropertiesANDROID::`formatFeatures` found by calling vkGetAndroidHardwareBufferPropertiesANDROID on the Android hardware buffer that was imported to the VkDeviceMemory to which the image is bound.

- If the image was created with `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`, then:

  - The image’s DRM format modifier is the value of VkImageDrmFormatModifierListCreateInfoEXT::`drmFormatModifier` found by calling vkGetImageDrmFormatModifierPropertiesEXT.

  - Let VkDrmFormatModifierPropertiesListEXT::`pDrmFormatModifierProperties` be the array found by calling vkGetPhysicalDeviceFormatProperties2 on the same `format` as VkImageCreateInfo::`format`.

  - Let `VkDrmFormatModifierPropertiesEXT prop` be the array element whose `drmFormatModifier` member is the value of the image’s DRM format modifier.

  - Then the image set of format features is the value of `prop`::`drmFormatModifierTilingFeatures`.

#### 11.3.2. Corner-Sampled Images

A corner-sampled image is an image where unnormalized texel coordinates are centered on integer values rather than half-integer values.

A corner-sampled image has a number of differences compared to conventional texture image:

- Texels are centered on integer coordinates. See Unnormalized Texel Coordinate Operations

- Normalized coordinates are scaled using coord * (dim - 1) rather than coord * dim, where dim is the size of one dimension of the image. See normalized texel coordinate transform.

- Partial derivatives are scaled using coord * (dim - 1) rather than coord * dim. See Scale Factor Operation.

- Calculation of the next higher lod size goes according to ⌈dim / 2⌉ rather than ⌊dim / 2⌋. See Image Miplevel Sizing.

- The minimum level size is 2x2 for 2D images and 2x2x2 for 3D images. See Image Miplevel Sizing.

Corner-sampling is only supported for 2D and 3D images. When sampling a corner-sampled image, the sampler addressing mode must be `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`. Corner-sampled images are not supported as cubemaps or depth/stencil images.

#### 11.3.3. Image Miplevel Sizing

A complete mipmap chain is the full set of miplevels, from the largest miplevel provided, down to the minimum miplevel size.

##### Conventional Images

For conventional images, the dimensions of each successive miplevel, n+1, are:

  `width`n+1 = max(⌊`width`n/2⌋, 1)

  `height`n+1 = max(⌊`height`n/2⌋, 1)

  `depth`n+1 = max(⌊`depth`n/2⌋, 1)

where `width`n, `height`n, and `depth`n are the dimensions of the next larger miplevel, n.

The minimum miplevel size is:

- 1 for one-dimensional images,

- 1x1 for two-dimensional images, and

- 1x1x1 for three-dimensional images.

The number of levels in a complete mipmap chain is:

  ⌊log2(max(`width`0, `height`0, `depth`0))⌋ + 1

where `width`0, `height`0, and `depth`0 are the dimensions of the largest (most detailed) miplevel, `0`.

##### Corner-Sampled Images

For corner-sampled images, the dimensions of each successive miplevel, n+1, are:

  `width`n+1 = max(⌈`width`n/2⌉, 2)

  `height`n+1 = max(⌈`height`n/2⌉, 2)

  `depth`n+1 = max(⌈`depth`n/2⌉, 2)

where `width`n, `height`n, and `depth`n are the dimensions of the next larger miplevel, n.

The minimum miplevel size is:

- 2x2 for two-dimensional images, and

- 2x2x2 for three-dimensional images.

The number of levels in a complete mipmap chain is:

  ⌈log2(max(`width`0, `height`0, `depth`0))⌉

where `width`0, `height`0, and `depth`0 are the dimensions of the largest (most detailed) miplevel, `0`.

### 11.4. Image Layouts

Images are stored in implementation-dependent opaque layouts in memory. Each layout has limitations on what kinds of operations are supported for image subresources using the layout. At any given time, the data representing an image subresource in memory exists in a particular layout which is determined by the most recent layout transition that was performed on that image subresource. Applications have control over which layout each image subresource uses, and can transition an image subresource from one layout to another. Transitions can happen with an image memory barrier, included as part of a `vkCmdPipelineBarrier` or a `vkCmdWaitEvents` command buffer command (see Image Memory Barriers), or as part of a subpass dependency within a render pass (see `VkSubpassDependency`). The image layout is per-image subresource, and separate image subresources of the same image can be in different layouts at the same time with one exception - depth and stencil aspects of a given image subresource must always be in the same layout.

| Note Each layout may offer optimal performance for a specific usage of image memory. For example, an image with a layout of `VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL` may provide optimal performance for use as a color attachment, but be unsupported for use in transfer commands. Applications can transition an image subresource from one layout to another in order to achieve optimal performance when the image subresource is used for multiple kinds of operations. After initialization, applications need not use any layout other than the general layout, though this may produce suboptimal performance on some implementations.

Upon creation, all image subresources of an image are initially in the same layout, where that layout is selected by the `VkImageCreateInfo`::`initialLayout` member. The `initialLayout` must be either `VK_IMAGE_LAYOUT_UNDEFINED` or `VK_IMAGE_LAYOUT_PREINITIALIZED`. If it is `VK_IMAGE_LAYOUT_PREINITIALIZED`, then the image data can be preinitialized by the host while using this layout, and the transition away from this layout will preserve that data. If it is `VK_IMAGE_LAYOUT_UNDEFINED`, then the contents of the data are considered to be undefined, and the transition away from this layout is not guaranteed to preserve that data. For either of these initial layouts, any image subresources must be transitioned to another layout before they are accessed by the device.

Host access to image memory is only well-defined for linear images and for image subresources of those images which are currently in either the `VK_IMAGE_LAYOUT_PREINITIALIZED` or `VK_IMAGE_LAYOUT_GENERAL` layout. Calling vkGetImageSubresourceLayout for a linear image returns a subresource layout mapping that is valid for either of those image layouts.

The set of image layouts consists of:

    typedef enum VkImageLayout {
        VK_IMAGE_LAYOUT_UNDEFINED = 0,
        VK_IMAGE_LAYOUT_GENERAL = 1,
        VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL = 2,
        VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL = 3,
        VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL = 4,
        VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL = 5,
        VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL = 6,
        VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL = 7,
        VK_IMAGE_LAYOUT_PREINITIALIZED = 8,
        VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL = 1000117000,
        VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL = 1000117001,
        VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL = 1000241000,
        VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL = 1000241001,
        VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL = 1000241002,
        VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL = 1000241003,
        VK_IMAGE_LAYOUT_PRESENT_SRC_KHR = 1000001002,
        VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR = 1000111000,
        VK_IMAGE_LAYOUT_SHADING_RATE_OPTIMAL_NV = 1000164003,
        VK_IMAGE_LAYOUT_FRAGMENT_DENSITY_MAP_OPTIMAL_EXT = 1000218000,
        VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL_KHR = VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL,
        VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL_KHR = VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL,
        VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL_KHR = VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL,
        VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL_KHR = VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL,
        VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL_KHR = VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL,
        VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL_KHR = VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL,
        VK_IMAGE_LAYOUT_MAX_ENUM = 0x7FFFFFFF
    } VkImageLayout;

The type(s) of device access supported by each layout are:

- `VK_IMAGE_LAYOUT_UNDEFINED` does not support device access. This layout must only be used as the `initialLayout` member of `VkImageCreateInfo` or `VkAttachmentDescription`, or as the `oldLayout` in an image transition. When transitioning out of this layout, the contents of the memory are not guaranteed to be preserved.

- `VK_IMAGE_LAYOUT_PREINITIALIZED` does not support device access. This layout must only be used as the `initialLayout` member of `VkImageCreateInfo` or `VkAttachmentDescription`, or as the `oldLayout` in an image transition. When transitioning out of this layout, the contents of the memory are preserved. This layout is intended to be used as the initial layout for an image whose contents are written by the host, and hence the data can be written to memory immediately, without first executing a layout transition. Currently, `VK_IMAGE_LAYOUT_PREINITIALIZED` is only useful with linear images because there is not a standard layout defined for `VK_IMAGE_TILING_OPTIMAL` images.

- `VK_IMAGE_LAYOUT_GENERAL` supports all types of device access.

- `VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL` must only be used as a color or resolve attachment in a `VkFramebuffer`. This layout is valid only for image subresources of images created with the `VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT` usage bit enabled.

- `VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL` specifies a layout for both the depth and stencil aspects of a depth/stencil format image allowing read and write access as a depth/stencil attachment. It is equivalent to `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL` and `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL`.

- `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL` specifies a layout for both the depth and stencil aspects of a depth/stencil format image allowing read only access as a depth/stencil attachment or in shaders. It is equivalent to `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL` and `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL`.

- `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL` specifies a layout for depth/stencil format images allowing read and write access to the stencil aspect as a stencil attachment, and read only access to the depth aspect as a depth attachment or in shaders. It is equivalent to `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL` and `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL`.

- `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL` specifies a layout for depth/stencil format images allowing read and write access to the depth aspect as a depth attachment, and read only access to the stencil aspect as a stencil attachment or in shaders. It is equivalent to `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL` and `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL`.

- `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL` specifies a layout for the depth aspect of a depth/stencil format image allowing read and write access as a depth attachment.

- `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL` specifies a layout for the depth aspect of a depth/stencil format image allowing read-only access as a depth attachment or in shaders.

- `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL` specifies a layout for the stencil aspect of a depth/stencil format image allowing read and write access as a stencil attachment.

- `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL` specifies a layout for the stencil aspect of a depth/stencil format image allowing read-only access as a stencil attachment or in shaders.

- `VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL` must only be used as a read-only image in a shader (which can be read as a sampled image, combined image/sampler and/or input attachment). This layout is valid only for image subresources of images created with the `VK_IMAGE_USAGE_SAMPLED_BIT` or `VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT` usage bit enabled.

- `VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL` must only be used as a source image of a transfer command (see the definition of `VK_PIPELINE_STAGE_TRANSFER_BIT`). This layout is valid only for image subresources of images created with the `VK_IMAGE_USAGE_TRANSFER_SRC_BIT` usage bit enabled.

- `VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL` must only be used as a destination image of a transfer command. This layout is valid only for image subresources of images created with the `VK_IMAGE_USAGE_TRANSFER_DST_BIT` usage bit enabled.

- `VK_IMAGE_LAYOUT_PRESENT_SRC_KHR` must only be used for presenting a presentable image for display. A swapchain’s image must be transitioned to this layout before calling vkQueuePresentKHR, and must be transitioned away from this layout after calling vkAcquireNextImageKHR.

- `VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR` is valid only for shared presentable images, and must be used for any usage the image supports.

- `VK_IMAGE_LAYOUT_SHADING_RATE_OPTIMAL_NV` must only be used as a read-only shading-rate-image. This layout is valid only for image subresources of images created with the `VK_IMAGE_USAGE_SHADING_RATE_IMAGE_BIT_NV` usage bit enabled.

- `VK_IMAGE_LAYOUT_FRAGMENT_DENSITY_MAP_OPTIMAL_EXT` must only be used as a fragment density map attachment in a `VkRenderPass`. This layout is valid only for image subresources of images created with the `VK_IMAGE_USAGE_FRAGMENT_DENSITY_MAP_BIT_EXT` usage bit enabled.

The layout of each image subresource is not a state of the image subresource itself, but is rather a property of how the data in memory is organized, and thus for each mechanism of accessing an image in the API the application must specify a parameter or structure member that indicates which image layout the image subresource(s) are considered to be in when the image will be accessed. For transfer commands, this is a parameter to the command (see Clear Commands and Copy Commands). For use as a framebuffer attachment, this is a member in the substructures of the `VkRenderPassCreateInfo` (see Render Pass). For use in a descriptor set, this is a member in the `VkDescriptorImageInfo` structure (see Descriptor Set Updates).

#### 11.4.1. Image Layout Matching Rules

At the time that any command buffer command accessing an image executes on any queue, the layouts of the image subresources that are accessed must all match exactly the layout specified via the API controlling those accesses , except in case of accesses to an image with a depth/stencil format performed through descriptors referring to only a single aspect of the image, where the following relaxed matching rules apply:

- Descriptors referring just to the depth aspect of a depth/stencil image only need to match in the image layout of the depth aspect, thus `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL` and `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL` are considered to match.

- Descriptors referring just to the stencil aspect of a depth/stencil image only need to match in the image layout of the stencil aspect, thus `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL` and `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL` are considered to match .

When performing a layout transition on an image subresource, the old layout value must either equal the current layout of the image subresource (at the time the transition executes), or else be `VK_IMAGE_LAYOUT_UNDEFINED` (implying that the contents of the image subresource need not be preserved). The new layout used in a transition must not be `VK_IMAGE_LAYOUT_UNDEFINED` or `VK_IMAGE_LAYOUT_PREINITIALIZED`.

The image layout of each image subresource of a depth/stencil image created with `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT` is dependent on the last sample locations used to render to the image subresource as a depth/stencil attachment, thus applications must provide the same sample locations that were last used to render to the given image subresource whenever a layout transition of the image subresource happens, otherwise the contents of the depth aspect of the image subresource become undefined.

In addition, depth reads from a depth/stencil attachment referring to an image subresource range of a depth/stencil image created with `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT` using different sample locations than what have been last used to perform depth writes to the image subresources of the same image subresource range return undefined values.

Similarly, depth writes to a depth/stencil attachment referring to an image subresource range of a depth/stencil image created with `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT` using different sample locations than what have been last used to perform depth writes to the image subresources of the same image subresource range make the contents of the depth aspect of those image subresources undefined.

### 11.5. Image Views

Image objects are not directly accessed by pipeline shaders for reading or writing image data. Instead, image views representing contiguous ranges of the image subresources and containing additional metadata are used for that purpose. Views must be created on images of compatible types, and must represent a valid subset of image subresources.

Image views are represented by `VkImageView` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkImageView)

The types of image views that can be created are:

    typedef enum VkImageViewType {
        VK_IMAGE_VIEW_TYPE_1D = 0,
        VK_IMAGE_VIEW_TYPE_2D = 1,
        VK_IMAGE_VIEW_TYPE_3D = 2,
        VK_IMAGE_VIEW_TYPE_CUBE = 3,
        VK_IMAGE_VIEW_TYPE_1D_ARRAY = 4,
        VK_IMAGE_VIEW_TYPE_2D_ARRAY = 5,
        VK_IMAGE_VIEW_TYPE_CUBE_ARRAY = 6,
        VK_IMAGE_VIEW_TYPE_MAX_ENUM = 0x7FFFFFFF
    } VkImageViewType;

The exact image view type is partially implicit, based on the image’s type and sample count, as well as the view creation parameters as described in the image view compatibility table for vkCreateImageView. This table also shows which SPIR-V `OpTypeImage` `Dim` and `Arrayed` parameters correspond to each image view type.

To create an image view, call:

    VkResult vkCreateImageView(
        VkDevice                                    device,
        const VkImageViewCreateInfo*                pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkImageView*                                pView);

- `device` is the logical device that creates the image view.

- `pCreateInfo` is a pointer to a `VkImageViewCreateInfo` structure containing parameters to be used to create the image view.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pView` is a pointer to a VkImageView handle in which the resulting image view object is returned.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkImageViewCreateInfo structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pView` must be a valid pointer to a VkImageView handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkImageViewCreateInfo` structure is defined as:

    typedef struct VkImageViewCreateInfo {
        VkStructureType            sType;
        const void*                pNext;
        VkImageViewCreateFlags     flags;
        VkImage                    image;
        VkImageViewType            viewType;
        VkFormat                   format;
        VkComponentMapping         components;
        VkImageSubresourceRange    subresourceRange;
    } VkImageViewCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkImageViewCreateFlagBits describing additional parameters of the image view.

- `image` is a VkImage on which the view will be created.

- `viewType` is a VkImageViewType value specifying the type of the image view.

- `format` is a VkFormat describing the format and type used to interpret texel blocks in the image.

- `components` is a VkComponentMapping specifies a remapping of color components (or of depth or stencil components after they have been converted into color components).

- `subresourceRange` is a VkImageSubresourceRange selecting the set of mipmap levels and array layers to be accessible to the view.

Some of the `image` creation parameters are inherited by the view. In particular, image view creation inherits the implicit parameter `usage` specifying the allowed usages of the image view that, by default, takes the value of the corresponding `usage` parameter specified in `VkImageCreateInfo` at image creation time. If the image was has a depth-stencil format and was created with a VkImageStencilUsageCreateInfo structure included in the `pNext` chain of VkImageCreateInfo, the usage is calculated based on the `subresource.aspectMask` provided:

- If `aspectMask` includes only `VK_IMAGE_ASPECT_STENCIL_BIT`, the implicit `usage` is equal to VkImageStencilUsageCreateInfo::`stencilUsage`.

- If `aspectMask` includes only `VK_IMAGE_ASPECT_DEPTH_BIT`, the implicit `usage` is equal to VkImageCreateInfo::`usage`.

- If both aspects are included in `aspectMask`, the implicit `usage` is equal to the intersection of VkImageCreateInfo::`usage` and VkImageStencilUsageCreateInfo::`stencilUsage`. The implicit `usage` can be overriden by adding a VkImageViewUsageCreateInfo structure to the `pNext` chain.

If `image` was created with the `VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT` flag, and if the `format` of the image is not multi-planar, `format` can be different from the image’s format, but if `image` was created without the `VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT` flag and they are not equal they must be compatible. Image format compatibility is defined in the Format Compatibility Classes section. Views of compatible formats will have the same mapping between texel coordinates and memory locations irrespective of the `format`, with only the interpretation of the bit pattern changing.

| Note Values intended to be used with one view format may not be exactly preserved when written or read through a different format. For example, an integer value that happens to have the bit pattern of a floating point denorm or NaN may be flushed or canonicalized when written or read through a view with a floating point format. Similarly, a value written through a signed normalized format that has a bit pattern exactly equal to -2b may be changed to -2b + 1 as described in Conversion from Normalized Fixed-Point to Floating-Point.

If `image` was created with the `VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT` flag, `format` must be compatible with the image’s format as described above, or must be an uncompressed format in which case it must be size-compatible with the image’s format, as defined for copying data between images In this case the resulting image view’s texel dimensions equal the dimensions of the selected mip level divided by the compressed texel block size and rounded up.

If the image view is to be used with a sampler which supports sampler Y′CBCR conversion, an identically defined object of type VkSamplerYcbcrConversion to that used to create the sampler must be passed to vkCreateImageView in a VkSamplerYcbcrConversionInfo included in the `pNext` chain of VkImageViewCreateInfo. Conversely, if a VkSamplerYcbcrConversion object is passed to vkCreateImageView, an identically defined VkSamplerYcbcrConversion object must be used when sampling the image.

If the image has a multi-planar `format` and `subresourceRange.aspectMask` is `VK_IMAGE_ASPECT_COLOR_BIT`, `format` must be identical to the image `format`, and the sampler to be used with the image view must enable sampler Y′CBCR conversion.

If `image` was created with the `VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT` and the image has a multi-planar `format`, and if `subresourceRange.aspectMask` is `VK_IMAGE_ASPECT_PLANE_0_BIT`, `VK_IMAGE_ASPECT_PLANE_1_BIT`, or `VK_IMAGE_ASPECT_PLANE_2_BIT`, `format` must be compatible with the corresponding plane of the image, and the sampler to be used with the image view must not enable sampler Y′CBCR conversion. The `width` and `height` of the single-plane image view must be derived from the multi-planar image’s dimensions in the manner listed for plane compatibility for the plane.

Any view of an image plane will have the same mapping between texel coordinates and memory locations as used by the channels of the color aspect, subject to the formulae relating texel coordinates to lower-resolution planes as described in Chroma Reconstruction. That is, if an R or B plane has a reduced resolution relative to the G plane of the multi-planar image, the image view operates using the (uplane, vplane) unnormalized coordinates of the reduced-resolution plane, and these coordinates access the same memory locations as the (ucolor, vcolor) unnormalized coordinates of the color aspect for which chroma reconstruction operations operate on the same (uplane, vplane) or (iplane, jplane) coordinates.

Table 15. Image and image view parameter compatibility requirements
Dim, Arrayed, MS | Image parameters | View parameters
--- | --- | ---
| `imageType` = ci.`imageType` `width` = ci.`extent.width` `height` = ci.`extent.height` `depth` = ci.`extent.depth` `arrayLayers` = ci.`arrayLayers` `samples` = ci.`samples` `flags` = ci.`flags` where ci is the VkImageCreateInfo used to create `image`. | `baseArrayLayer`, `layerCount`, and `levelCount` are members of the `subresourceRange` member.
1D, 0, 0 | `imageType` = `VK_IMAGE_TYPE_1D` `width` ≥ 1 `height` = 1 `depth` = 1 `arrayLayers` ≥ 1 `samples` = 1 | `viewType` = `VK_IMAGE_VIEW_TYPE_1D` `baseArrayLayer` ≥ 0 `layerCount` = 1
1D, 1, 0 | `imageType` = `VK_IMAGE_TYPE_1D` `width` ≥ 1 `height` = 1 `depth` = 1 `arrayLayers` ≥ 1 `samples` = 1 | `viewType` = `VK_IMAGE_VIEW_TYPE_1D_ARRAY` `baseArrayLayer` ≥ 0 `layerCount` ≥ 1
2D, 0, 0 | `imageType` = `VK_IMAGE_TYPE_2D` `width` ≥ 1 `height` ≥ 1 `depth` = 1 `arrayLayers` ≥ 1 `samples` = 1 | `viewType` = `VK_IMAGE_VIEW_TYPE_2D` `baseArrayLayer` ≥ 0 `layerCount` = 1
2D, 1, 0 | `imageType` = `VK_IMAGE_TYPE_2D` `width` ≥ 1 `height` ≥ 1 `depth` = 1 `arrayLayers` ≥ 1 `samples` = 1 | `viewType` = `VK_IMAGE_VIEW_TYPE_2D_ARRAY` `baseArrayLayer` ≥ 0 `layerCount` ≥ 1
2D, 0, 1 | `imageType` = `VK_IMAGE_TYPE_2D` `width` ≥ 1 `height` ≥ 1 `depth` = 1 `arrayLayers` ≥ 1 `samples` > 1 | `viewType` = `VK_IMAGE_VIEW_TYPE_2D` `baseArrayLayer` ≥ 0 `layerCount` = 1
2D, 1, 1 | `imageType` = `VK_IMAGE_TYPE_2D` `width` ≥ 1 `height` ≥ 1 `depth` = 1 `arrayLayers` ≥ 1 `samples` > 1 | `viewType` = `VK_IMAGE_VIEW_TYPE_2D_ARRAY` `baseArrayLayer` ≥ 0 `layerCount` ≥ 1
CUBE, 0, 0 | `imageType` = `VK_IMAGE_TYPE_2D` `width` ≥ 1 `height` = `width` `depth` = 1 `arrayLayers` ≥ 6 `samples` = 1 `flags` includes `VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT` | `viewType` = `VK_IMAGE_VIEW_TYPE_CUBE` `baseArrayLayer` ≥ 0 `layerCount` = 6
CUBE, 1, 0 | `imageType` = `VK_IMAGE_TYPE_2D` `width` ≥ 1 `height` = width `depth` = 1 N ≥ 1 `arrayLayers` ≥ 6 × N `samples` = 1 `flags` includes `VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT` | `viewType` = `VK_IMAGE_VIEW_TYPE_CUBE_ARRAY` `baseArrayLayer` ≥ 0 `layerCount` = 6 × N, N ≥ 1
3D, 0, 0 | `imageType` = `VK_IMAGE_TYPE_3D` `width` ≥ 1 `height` ≥ 1 `depth` ≥ 1 `arrayLayers` = 1 `samples` = 1 | `viewType` = `VK_IMAGE_VIEW_TYPE_3D` `baseArrayLayer` = 0 `layerCount` = 1
3D, 0, 0 | `imageType` = `VK_IMAGE_TYPE_3D` `width` ≥ 1 `height` ≥ 1 `depth` ≥ 1 `arrayLayers` = 1 `samples` = 1 `flags` includes `VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT` `flags` does not include `VK_IMAGE_CREATE_SPARSE_BINDING_BIT`, `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`, and `VK_IMAGE_CREATE_SPARSE_ALIASED_BIT` | `viewType` = `VK_IMAGE_VIEW_TYPE_2D` `levelCount` = 1 `baseArrayLayer` ≥ 0 `layerCount` = 1
3D, 0, 0 | `imageType` = `VK_IMAGE_TYPE_3D` `width` ≥ 1 `height` ≥ 1 `depth` ≥ 1 `arrayLayers` = 1 `samples` = 1 `flags` includes `VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT` `flags` does not include `VK_IMAGE_CREATE_SPARSE_BINDING_BIT`, `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`, and `VK_IMAGE_CREATE_SPARSE_ALIASED_BIT` | `viewType` = `VK_IMAGE_VIEW_TYPE_2D_ARRAY` `levelCount` = 1 `baseArrayLayer` ≥ 0 `layerCount` ≥ 1

Valid Usage

- If `image` was not created with `VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT` then `viewType` must not be `VK_IMAGE_VIEW_TYPE_CUBE` or `VK_IMAGE_VIEW_TYPE_CUBE_ARRAY`

- If the image cubemap arrays feature is not enabled, `viewType` must not be `VK_IMAGE_VIEW_TYPE_CUBE_ARRAY`

- If `image` was created with `VK_IMAGE_TYPE_3D` but without `VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT` set then `viewType` must not be `VK_IMAGE_VIEW_TYPE_2D` or `VK_IMAGE_VIEW_TYPE_2D_ARRAY`

- `image` must have been created with a `usage` value containing at least one of `VK_IMAGE_USAGE_SAMPLED_BIT`, `VK_IMAGE_USAGE_STORAGE_BIT`, `VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT`, `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT`, `VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT`, `VK_IMAGE_USAGE_SHADING_RATE_IMAGE_BIT_NV`, or `VK_IMAGE_USAGE_FRAGMENT_DENSITY_MAP_BIT_EXT`

- The format features of the resultant image view must contain at least one bit.

- If `usage` contains `VK_IMAGE_USAGE_SAMPLED_BIT`, then the format features of the resultant image view must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT`.

- If `usage` contains `VK_IMAGE_USAGE_STORAGE_BIT`, then the image view’s format features must contain `VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT`.

- If `usage` contains `VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT`, then the image view’s format features must contain `VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT`.

- If `usage` contains `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT`, then the image view’s format features must contain `VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT`.

- If `usage` contains `VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT`, then the image view’s format features must contain at least one of `VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT` or `VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT`.

- `subresourceRange.baseMipLevel` must be less than the `mipLevels` specified in VkImageCreateInfo when `image` was created

- If `subresourceRange.levelCount` is not `VK_REMAINING_MIP_LEVELS`, `subresourceRange.baseMipLevel` + `subresourceRange.levelCount` must be less than or equal to the `mipLevels` specified in VkImageCreateInfo when `image` was created

- If `image` was created with `usage` containing `VK_IMAGE_USAGE_FRAGMENT_DENSITY_MAP_BIT_EXT`, `subresourceRange.levelCount` must be `1`

- If `image` is not a 3D image created with `VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT` set, or `viewType` is not `VK_IMAGE_VIEW_TYPE_2D` or `VK_IMAGE_VIEW_TYPE_2D_ARRAY`, `subresourceRange.baseArrayLayer` must be less than the `arrayLayers` specified in VkImageCreateInfo when `image` was created

- If `subresourceRange.layerCount` is not `VK_REMAINING_ARRAY_LAYERS`, `image` is not a 3D image created with `VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT` set, or `viewType` is not `VK_IMAGE_VIEW_TYPE_2D` or `VK_IMAGE_VIEW_TYPE_2D_ARRAY`, `subresourceRange.layerCount` must be non-zero and `subresourceRange.baseArrayLayer` + `subresourceRange.layerCount` must be less than or equal to the `arrayLayers` specified in VkImageCreateInfo when `image` was created

- If `image` is a 3D image created with `VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT` set, and `viewType` is `VK_IMAGE_VIEW_TYPE_2D` or `VK_IMAGE_VIEW_TYPE_2D_ARRAY`, `subresourceRange.baseArrayLayer` must be less than the depth computed from `baseMipLevel` and `extent.depth` specified in VkImageCreateInfo when `image` was created, according to the formula defined in Image Miplevel Sizing.

- If `subresourceRange.layerCount` is not `VK_REMAINING_ARRAY_LAYERS`, `image` is a 3D image created with `VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT` set, and `viewType` is `VK_IMAGE_VIEW_TYPE_2D` or `VK_IMAGE_VIEW_TYPE_2D_ARRAY`, `subresourceRange.layerCount` must be non-zero and `subresourceRange.baseArrayLayer` + `subresourceRange.layerCount` must be less than or equal to the depth computed from `baseMipLevel` and `extent.depth` specified in VkImageCreateInfo when `image` was created, according to the formula defined in Image Miplevel Sizing.

- If `image` was created with the `VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT` flag, but without the `VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT` flag, and if the `format` of the `image` is not a multi-planar format, `format` must be compatible with the `format` used to create `image`, as defined in Format Compatibility Classes

- If `image` was created with the `VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT` flag, `format` must be compatible with, or must be an uncompressed format that is size-compatible with, the `format` used to create `image`.

- If `image` was created with the `VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT` flag, the `levelCount` and `layerCount` members of `subresourceRange` must both be `1`.

- If a `VkImageFormatListCreateInfo` structure was included in the `pNext` chain of the `VkImageCreateInfo` structure used when creating `image` and the `viewFormatCount` field of `VkImageFormatListCreateInfo` is not zero then `format` must be one of the formats in `VkImageFormatListCreateInfo`::`pViewFormats`.

- If `image` was created with the `VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT` flag, if the `format` of the `image` is a multi-planar format, and if `subresourceRange.aspectMask` is one of `VK_IMAGE_ASPECT_PLANE_0_BIT`, `VK_IMAGE_ASPECT_PLANE_1_BIT`, or `VK_IMAGE_ASPECT_PLANE_2_BIT`, then `format` must be compatible with the VkFormat for the plane of the `image` `format` indicated by `subresourceRange.aspectMask`, as defined in Compatible formats of planes of multi-planar formats

- If `image` was not created with the `VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT` flag, or if the `format` of the `image` is a multi-planar format and if `subresourceRange.aspectMask` is `VK_IMAGE_ASPECT_COLOR_BIT`, `format` must be identical to the `format` used to create `image`

- If the `pNext` chain includes a VkSamplerYcbcrConversionInfo structure with a `conversion` value other than VK_NULL_HANDLE, all members of `components` must have the value `VK_COMPONENT_SWIZZLE_IDENTITY`.

- If `image` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `subresourceRange` and `viewType` must be compatible with the image, as described in the compatibility table

- If `image` has an external format, `format` must be `VK_FORMAT_UNDEFINED`.

- If `image` has an external format, the `pNext` chain must include a VkSamplerYcbcrConversionInfo structure with a `conversion` object created with the same external format as `image`.

- If `image` has an external format, all members of `components` must be `VK_COMPONENT_SWIZZLE_IDENTITY`.

- If `image` was created with `usage` containing `VK_IMAGE_USAGE_SHADING_RATE_IMAGE_BIT_NV`, `viewType` must be `VK_IMAGE_VIEW_TYPE_2D` or `VK_IMAGE_VIEW_TYPE_2D_ARRAY`

- If `image` was created with `usage` containing `VK_IMAGE_USAGE_SHADING_RATE_IMAGE_BIT_NV`, `format` must be `VK_FORMAT_R8_UINT`

- If dynamic fragment density map feature is not enabled, `flags` must not contain `VK_IMAGE_VIEW_CREATE_FRAGMENT_DENSITY_MAP_DYNAMIC_BIT_EXT`

- If dynamic fragment density map feature is not enabled and `image` was created with `usage` containing `VK_IMAGE_USAGE_FRAGMENT_DENSITY_MAP_BIT_EXT`, `flags` must not contain any of `VK_IMAGE_CREATE_PROTECTED_BIT`, `VK_IMAGE_CREATE_SPARSE_BINDING_BIT`, `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`, or `VK_IMAGE_CREATE_SPARSE_ALIASED_BIT`

- If the `pNext` chain includes a VkImageViewUsageCreateInfo structure, and `image` was not created with a VkImageStencilUsageCreateInfo structure included in the `pNext` chain of VkImageCreateInfo, its `usage` member must not include any bits that were not set in the `usage` member of the VkImageCreateInfo structure used to create `image`

- If the `pNext` chain includes a VkImageViewUsageCreateInfo structure, `image` was created with a VkImageStencilUsageCreateInfo structure included in the `pNext` chain of VkImageCreateInfo, and `subResourceRange.aspectMask` includes `VK_IMAGE_ASPECT_STENCIL_BIT`, the `usage` member of the VkImageViewUsageCreateInfo instance must not include any bits that were not set in the `usage` member of the VkImageStencilUsageCreateInfo structure used to create `image`

- If the `pNext` chain includes a VkImageViewUsageCreateInfo structure, `image` was created with a VkImageStencilUsageCreateInfo structure included in the `pNext` chain of VkImageCreateInfo, and `subResourceRange.aspectMask` includes bits other than `VK_IMAGE_ASPECT_STENCIL_BIT`, the `usage` member of the VkImageViewUsageCreateInfo structure must not include any bits that were not set in the `usage` member of the VkImageCreateInfo structure used to create `image`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkImageViewASTCDecodeModeEXT, VkImageViewUsageCreateInfo, or VkSamplerYcbcrConversionInfo

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be a valid combination of VkImageViewCreateFlagBits values

- `image` must be a valid VkImage handle

- `viewType` must be a valid VkImageViewType value

- `format` must be a valid VkFormat value

- `components` must be a valid VkComponentMapping structure

- `subresourceRange` must be a valid VkImageSubresourceRange structure

Bits which can be set in VkImageViewCreateInfo::`flags`, specifying additional parameters of an image, are:

    typedef enum VkImageViewCreateFlagBits {
        VK_IMAGE_VIEW_CREATE_FRAGMENT_DENSITY_MAP_DYNAMIC_BIT_EXT = 0x00000001,
        VK_IMAGE_VIEW_CREATE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkImageViewCreateFlagBits;

- `VK_IMAGE_VIEW_CREATE_FRAGMENT_DENSITY_MAP_DYNAMIC_BIT_EXT` prohibits the implementation from accessing the fragment density map by the host during `vkCmdBeginRenderPass` as the contents are expected to change after recording

    typedef VkFlags VkImageViewCreateFlags;

`VkImageViewCreateFlags` is a bitmask type for setting a mask of zero or more VkImageViewCreateFlagBits.

The set of usages for the created image view can be restricted compared to the parent image’s `usage` flags by adding a `VkImageViewUsageCreateInfo` structure to the `pNext` chain of `VkImageViewCreateInfo`.

The `VkImageViewUsageCreateInfo` structure is defined as:

    typedef struct VkImageViewUsageCreateInfo {
        VkStructureType      sType;
        const void*          pNext;
        VkImageUsageFlags    usage;
    } VkImageViewUsageCreateInfo;

or the equivalent

    typedef VkImageViewUsageCreateInfo VkImageViewUsageCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `usage` is a bitmask describing the allowed usages of the image view. See VkImageUsageFlagBits for a description of the supported bits.

When this structure is chained to `VkImageViewCreateInfo` the `usage` field overrides the implicit `usage` parameter inherited from image creation time and its value is used instead for the purposes of determining the valid usage conditions of VkImageViewCreateInfo.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMAGE_VIEW_USAGE_CREATE_INFO`

- `usage` must be a valid combination of VkImageUsageFlagBits values

- `usage` must not be `0`

The `VkImageSubresourceRange` structure is defined as:

    typedef struct VkImageSubresourceRange {
        VkImageAspectFlags    aspectMask;
        uint32_t              baseMipLevel;
        uint32_t              levelCount;
        uint32_t              baseArrayLayer;
        uint32_t              layerCount;
    } VkImageSubresourceRange;

- `aspectMask` is a bitmask of VkImageAspectFlagBits specifying which aspect(s) of the image are included in the view.

- `baseMipLevel` is the first mipmap level accessible to the view.

- `levelCount` is the number of mipmap levels (starting from `baseMipLevel`) accessible to the view.

- `baseArrayLayer` is the first array layer accessible to the view.

- `layerCount` is the number of array layers (starting from `baseArrayLayer`) accessible to the view.

The number of mipmap levels and array layers must be a subset of the image subresources in the image. If an application wants to use all mip levels or layers in an image after the `baseMipLevel` or `baseArrayLayer`, it can set `levelCount` and `layerCount` to the special values `VK_REMAINING_MIP_LEVELS` and `VK_REMAINING_ARRAY_LAYERS` without knowing the exact number of mip levels or layers.

For cube and cube array image views, the layers of the image view starting at `baseArrayLayer` correspond to faces in the order +X, -X, +Y, -Y, +Z, -Z. For cube arrays, each set of six sequential layers is a single cube, so the number of cube maps in a cube map array view is `layerCount` / 6, and image array layer (`baseArrayLayer` + i) is face index (i mod 6) of cube i / 6. If the number of layers in the view, whether set explicitly in `layerCount` or implied by `VK_REMAINING_ARRAY_LAYERS`, is not a multiple of 6, the last cube map in the array must not be accessed.

`aspectMask` must be only `VK_IMAGE_ASPECT_COLOR_BIT`, `VK_IMAGE_ASPECT_DEPTH_BIT` or `VK_IMAGE_ASPECT_STENCIL_BIT` if `format` is a color, depth-only or stencil-only format, respectively, except if `format` is a multi-planar format. If using a depth/stencil format with both depth and stencil components, `aspectMask` must include at least one of `VK_IMAGE_ASPECT_DEPTH_BIT` and `VK_IMAGE_ASPECT_STENCIL_BIT`, and can include both.

When the `VkImageSubresourceRange` structure is used to select a subset of the slices of a 3D image’s mip level in order to create a 2D or 2D array image view of a 3D image created with `VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT`, `baseArrayLayer` and `layerCount` specify the first slice index and the number of slices to include in the created image view. Such an image view can be used as a framebuffer attachment that refers only to the specified range of slices of the selected mip level. However, any layout transitions performed on such an attachment view during a render pass instance still apply to the entire subresource referenced which includes all the slices of the selected mip level.

When using an image view of a depth/stencil image to populate a descriptor set (e.g. for sampling in the shader, or for use as an input attachment), the `aspectMask` must only include one bit and selects whether the image view is used for depth reads (i.e. using a floating-point sampler or input attachment in the shader) or stencil reads (i.e. using an unsigned integer sampler or input attachment in the shader). When an image view of a depth/stencil image is used as a depth/stencil framebuffer attachment, the `aspectMask` is ignored and both depth and stencil image subresources are used.

The VkComponentMapping `components` member describes a remapping from components of the image to components of the vector returned by shader image instructions. This remapping must be identity for storage image descriptors, input attachment descriptors, framebuffer attachments, and any `VkImageView` used with a combined image sampler that enables sampler Y′CBCR conversion.

When creating a `VkImageView`, if sampler Y′CBCR conversion is enabled in the sampler, the `aspectMask` of a `subresourceRange` used by the `VkImageView` must be `VK_IMAGE_ASPECT_COLOR_BIT`.

When creating a `VkImageView`, if sampler Y′CBCR conversion is not enabled in the sampler and the image `format` is multi-planar, the image must have been created with `VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT`, and the `aspectMask` of the `VkImageView`’s `subresourceRange` must be `VK_IMAGE_ASPECT_PLANE_0_BIT`, `VK_IMAGE_ASPECT_PLANE_1_BIT` or `VK_IMAGE_ASPECT_PLANE_2_BIT`.

Valid Usage

- If `levelCount` is not `VK_REMAINING_MIP_LEVELS`, it must be greater than `0`

- If `layerCount` is not `VK_REMAINING_ARRAY_LAYERS`, it must be greater than `0`

- If `aspectMask` includes `VK_IMAGE_ASPECT_COLOR_BIT`, then it must not include any of `VK_IMAGE_ASPECT_PLANE_0_BIT`, `VK_IMAGE_ASPECT_PLANE_1_BIT`, or `VK_IMAGE_ASPECT_PLANE_2_BIT`

- `aspectMask` must not include `VK_IMAGE_ASPECT_MEMORY_PLANE_i_BIT_EXT` for any index `i`

Valid Usage (Implicit)

- `aspectMask` must be a valid combination of VkImageAspectFlagBits values

- `aspectMask` must not be `0`

Bits which can be set in an aspect mask to specify aspects of an image for purposes such as identifying a subresource, are:

    typedef enum VkImageAspectFlagBits {
        VK_IMAGE_ASPECT_COLOR_BIT = 0x00000001,
        VK_IMAGE_ASPECT_DEPTH_BIT = 0x00000002,
        VK_IMAGE_ASPECT_STENCIL_BIT = 0x00000004,
        VK_IMAGE_ASPECT_METADATA_BIT = 0x00000008,
        VK_IMAGE_ASPECT_PLANE_0_BIT = 0x00000010,
        VK_IMAGE_ASPECT_PLANE_1_BIT = 0x00000020,
        VK_IMAGE_ASPECT_PLANE_2_BIT = 0x00000040,
        VK_IMAGE_ASPECT_MEMORY_PLANE_0_BIT_EXT = 0x00000080,
        VK_IMAGE_ASPECT_MEMORY_PLANE_1_BIT_EXT = 0x00000100,
        VK_IMAGE_ASPECT_MEMORY_PLANE_2_BIT_EXT = 0x00000200,
        VK_IMAGE_ASPECT_MEMORY_PLANE_3_BIT_EXT = 0x00000400,
        VK_IMAGE_ASPECT_PLANE_0_BIT_KHR = VK_IMAGE_ASPECT_PLANE_0_BIT,
        VK_IMAGE_ASPECT_PLANE_1_BIT_KHR = VK_IMAGE_ASPECT_PLANE_1_BIT,
        VK_IMAGE_ASPECT_PLANE_2_BIT_KHR = VK_IMAGE_ASPECT_PLANE_2_BIT,
        VK_IMAGE_ASPECT_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkImageAspectFlagBits;

- `VK_IMAGE_ASPECT_COLOR_BIT` specifies the color aspect.

- `VK_IMAGE_ASPECT_DEPTH_BIT` specifies the depth aspect.

- `VK_IMAGE_ASPECT_STENCIL_BIT` specifies the stencil aspect.

- `VK_IMAGE_ASPECT_METADATA_BIT` specifies the metadata aspect, used for sparse sparse resource operations.

- `VK_IMAGE_ASPECT_PLANE_0_BIT` specifies plane 0 of a multi-planar image format.

- `VK_IMAGE_ASPECT_PLANE_1_BIT` specifies plane 1 of a multi-planar image format.

- `VK_IMAGE_ASPECT_PLANE_2_BIT` specifies plane 2 of a multi-planar image format.

- `VK_IMAGE_ASPECT_MEMORY_PLANE_0_BIT_EXT` specifies memory plane 0.

- `VK_IMAGE_ASPECT_MEMORY_PLANE_1_BIT_EXT` specifies memory plane 1.

- `VK_IMAGE_ASPECT_MEMORY_PLANE_2_BIT_EXT` specifies memory plane 2.

- `VK_IMAGE_ASPECT_MEMORY_PLANE_3_BIT_EXT` specifies memory plane 3.

    typedef VkFlags VkImageAspectFlags;

`VkImageAspectFlags` is a bitmask type for setting a mask of zero or more VkImageAspectFlagBits.

The `VkComponentMapping` structure is defined as:

    typedef struct VkComponentMapping {
        VkComponentSwizzle    r;
        VkComponentSwizzle    g;
        VkComponentSwizzle    b;
        VkComponentSwizzle    a;
    } VkComponentMapping;

- `r` is a VkComponentSwizzle specifying the component value placed in the R component of the output vector.

- `g` is a VkComponentSwizzle specifying the component value placed in the G component of the output vector.

- `b` is a VkComponentSwizzle specifying the component value placed in the B component of the output vector.

- `a` is a VkComponentSwizzle specifying the component value placed in the A component of the output vector.

Valid Usage (Implicit)

- `r` must be a valid VkComponentSwizzle value

- `g` must be a valid VkComponentSwizzle value

- `b` must be a valid VkComponentSwizzle value

- `a` must be a valid VkComponentSwizzle value

Possible values of the members of VkComponentMapping, specifying the component values placed in each component of the output vector, are:

    typedef enum VkComponentSwizzle {
        VK_COMPONENT_SWIZZLE_IDENTITY = 0,
        VK_COMPONENT_SWIZZLE_ZERO = 1,
        VK_COMPONENT_SWIZZLE_ONE = 2,
        VK_COMPONENT_SWIZZLE_R = 3,
        VK_COMPONENT_SWIZZLE_G = 4,
        VK_COMPONENT_SWIZZLE_B = 5,
        VK_COMPONENT_SWIZZLE_A = 6,
        VK_COMPONENT_SWIZZLE_MAX_ENUM = 0x7FFFFFFF
    } VkComponentSwizzle;

- `VK_COMPONENT_SWIZZLE_IDENTITY` specifies that the component is set to the identity swizzle.

- `VK_COMPONENT_SWIZZLE_ZERO` specifies that the component is set to zero.

- `VK_COMPONENT_SWIZZLE_ONE` specifies that the component is set to either 1 or 1.0, depending on whether the type of the image view format is integer or floating-point respectively, as determined by the Format Definition section for each VkFormat.

- `VK_COMPONENT_SWIZZLE_R` specifies that the component is set to the value of the R component of the image.

- `VK_COMPONENT_SWIZZLE_G` specifies that the component is set to the value of the G component of the image.

- `VK_COMPONENT_SWIZZLE_B` specifies that the component is set to the value of the B component of the image.

- `VK_COMPONENT_SWIZZLE_A` specifies that the component is set to the value of the A component of the image.

Setting the identity swizzle on a component is equivalent to setting the identity mapping on that component. That is:

Table 16. Component Mappings Equivalent To `VK_COMPONENT_SWIZZLE_IDENTITY`
Component | Identity Mapping
--- | ---
`components.r` | `VK_COMPONENT_SWIZZLE_R`
`components.g` | `VK_COMPONENT_SWIZZLE_G`
`components.b` | `VK_COMPONENT_SWIZZLE_B`
`components.a` | `VK_COMPONENT_SWIZZLE_A`

If the `pNext` list includes a `VkImageViewASTCDecodeModeEXT` structure, then that structure includes a parameter specifying the decode mode for image views using ASTC compressed formats.

The `VkImageViewASTCDecodeModeEXT` structure is defined as:

    typedef struct VkImageViewASTCDecodeModeEXT {
        VkStructureType    sType;
        const void*        pNext;
        VkFormat           decodeMode;
    } VkImageViewASTCDecodeModeEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `decodeMode` is the intermediate format used to decode ASTC compressed formats.

Valid Usage

- `decodeMode` must be one of `VK_FORMAT_R16G16B16A16_SFLOAT`, `VK_FORMAT_R8G8B8A8_UNORM`, or `VK_FORMAT_E5B9G9R9_UFLOAT_PACK32`

- If the `decodeModeSharedExponent` feature is not enabled, `decodeMode` must not be `VK_FORMAT_E5B9G9R9_UFLOAT_PACK32`

- If `decodeMode` is `VK_FORMAT_R8G8B8A8_UNORM` the image view must not include blocks using any of the ASTC HDR modes

- `format` of the image view must be one of `VK_FORMAT_ASTC_4x4_UNORM_BLOCK`, `VK_FORMAT_ASTC_4x4_SRGB_BLOCK`, `VK_FORMAT_ASTC_5x4_UNORM_BLOCK`, `VK_FORMAT_ASTC_5x4_SRGB_BLOCK`, `VK_FORMAT_ASTC_5x5_UNORM_BLOCK`, `VK_FORMAT_ASTC_5x5_SRGB_BLOCK`, `VK_FORMAT_ASTC_6x5_UNORM_BLOCK`, `VK_FORMAT_ASTC_6x5_SRGB_BLOCK`, `VK_FORMAT_ASTC_6x6_UNORM_BLOCK`, `VK_FORMAT_ASTC_6x6_SRGB_BLOCK`, `VK_FORMAT_ASTC_8x5_UNORM_BLOCK`, `VK_FORMAT_ASTC_8x5_SRGB_BLOCK`, `VK_FORMAT_ASTC_8x6_UNORM_BLOCK`, `VK_FORMAT_ASTC_8x6_SRGB_BLOCK`, `VK_FORMAT_ASTC_8x8_UNORM_BLOCK`, `VK_FORMAT_ASTC_8x8_SRGB_BLOCK`, `VK_FORMAT_ASTC_10x5_UNORM_BLOCK`, `VK_FORMAT_ASTC_10x5_SRGB_BLOCK`, `VK_FORMAT_ASTC_10x6_UNORM_BLOCK`, `VK_FORMAT_ASTC_10x6_SRGB_BLOCK`, `VK_FORMAT_ASTC_10x8_UNORM_BLOCK`, `VK_FORMAT_ASTC_10x8_SRGB_BLOCK`, `VK_FORMAT_ASTC_10x10_UNORM_BLOCK`, `VK_FORMAT_ASTC_10x10_SRGB_BLOCK`, `VK_FORMAT_ASTC_12x10_UNORM_BLOCK`, `VK_FORMAT_ASTC_12x10_SRGB_BLOCK`, `VK_FORMAT_ASTC_12x12_UNORM_BLOCK`, or `VK_FORMAT_ASTC_12x12_SRGB_BLOCK`

If `format` uses sRGB encoding then the `decodeMode` has no effect.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMAGE_VIEW_ASTC_DECODE_MODE_EXT`

- `decodeMode` must be a valid VkFormat value

To destroy an image view, call:

    void vkDestroyImageView(
        VkDevice                                    device,
        VkImageView                                 imageView,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that destroys the image view.

- `imageView` is the image view to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage

- All submitted commands that refer to `imageView` must have completed execution

- If `VkAllocationCallbacks` were provided when `imageView` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `imageView` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `imageView` is not VK_NULL_HANDLE, `imageView` must be a valid VkImageView handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- If `imageView` is a valid handle, it must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `imageView` must be externally synchronized

To get the handle for an image view, call:

    uint32_t vkGetImageViewHandleNVX(
        VkDevice                                    device,
        const VkImageViewHandleInfoNVX*             pInfo);

- `device` is the logical device that owns the image view.

- `pInfo` describes the image view to query and type of handle.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pInfo` must be a valid pointer to a valid VkImageViewHandleInfoNVX structure

The `VkImageViewHandleInfoNVX` structure is defined as:

    typedef struct VkImageViewHandleInfoNVX {
        VkStructureType     sType;
        const void*         pNext;
        VkImageView         imageView;
        VkDescriptorType    descriptorType;
        VkSampler           sampler;
    } VkImageViewHandleInfoNVX;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `imageView` is the image view to query.

- `descriptorType` is the type of descriptor for which to query a handle.

- `sampler` is the sampler to combine with the image view when generating the handle.

Valid Usage

- `descriptorType` must be `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE`, `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE`, or `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`

- `sampler` must be a valid VkSampler if `descriptorType` is `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`

- If descriptorType is `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE` or `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, the image that `imageView` was created from must have been created with the `VK_IMAGE_USAGE_SAMPLED_BIT` usage bit set

- If descriptorType is `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE`, the image that `imageView` was created from must have been created with the `VK_IMAGE_USAGE_STORAGE_BIT` usage bit set

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMAGE_VIEW_HANDLE_INFO_NVX`

- `pNext` must be `NULL`

- `imageView` must be a valid VkImageView handle

- `descriptorType` must be a valid VkDescriptorType value

- If `sampler` is not VK_NULL_HANDLE, `sampler` must be a valid VkSampler handle

- Both of `imageView`, and `sampler` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

#### 11.5.1. Image View Format Features

Valid usage of a VkImageView may be constrained by the image view’s format features, defined below. Such constraints are documented in the affected valid usage statement.

- If the view’s image was created with `VK_IMAGE_TILING_LINEAR`, then the image view’s set of format features is the value of VkFormatProperties::`linearTilingFeatures` found by calling vkGetPhysicalDeviceFormatProperties on the same `format` as VkImageViewCreateInfo::`format`.

- If the view’s image was created with `VK_IMAGE_TILING_OPTIMAL`, but without an external format, then the image view’s set of format features is the value of VkFormatProperties::`optimalTilingFeatures` found by calling vkGetPhysicalDeviceFormatProperties on the same `format` as VkImageViewCreateInfo::`format`.

- If the view’s image was created with an external format, then the image views’s set of format features is the value of VkAndroidHardwareBufferFormatPropertiesANDROID::`formatFeatures` found by calling vkGetAndroidHardwareBufferPropertiesANDROID on the Android hardware buffer that was imported to the VkDeviceMemory to which the image is bound.

- If the view’s image was created with `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`, then:

  - The image’s DRM format modifier is the value of VkImageDrmFormatModifierListCreateInfoEXT::`drmFormatModifier` found by calling vkGetImageDrmFormatModifierPropertiesEXT.

  - Let VkDrmFormatModifierPropertiesListEXT::`pDrmFormatModifierProperties` be the array found by calling vkGetPhysicalDeviceFormatProperties2 on the same `format` as VkImageViewCreateInfo::`format`.

  - Let `VkDrmFormatModifierPropertiesEXT prop` be the array element whose `drmFormatModifier` member is the value of the image’s DRM format modifier.

  - Then the image view’s set of format features is the value of `prop`::`drmFormatModifierTilingFeatures`.

### 11.6. Resource Memory Association

Resources are initially created as virtual allocations with no backing memory. Device memory is allocated separately (see Device Memory) and then associated with the resource. This association is done differently for sparse and non-sparse resources.

Resources created with any of the sparse creation flags are considered sparse resources. Resources created without these flags are non-sparse. The details on resource memory association for sparse resources is described in Sparse Resources.

Non-sparse resources must be bound completely and contiguously to a single `VkDeviceMemory` object before the resource is passed as a parameter to any of the following operations:

- creating image or buffer views

- updating descriptor sets

- recording commands in a command buffer

Once bound, the memory binding is immutable for the lifetime of the resource.

In a logical device representing more than one physical device, buffer and image resources exist on all physical devices but can be bound to memory differently on each. Each such replicated resource is an instance of the resource. For sparse resources, each instance can be bound to memory arbitrarily differently. For non-sparse resources, each instance can either be bound to the local or a peer instance of the memory, or for images can be bound to rectangular regions from the local and/or peer instances. When a resource is used in a descriptor set, each physical device interprets the descriptor according to its own instance’s binding to memory.

| Note There are no new copy commands to transfer data between physical devices. Instead, an application can create a resource with a peer mapping and use it as the source or destination of a transfer command executed by a single physical device to copy the data from one physical device to another.

To determine the memory requirements for a buffer resource, call:

    void vkGetBufferMemoryRequirements(
        VkDevice                                    device,
        VkBuffer                                    buffer,
        VkMemoryRequirements*                       pMemoryRequirements);

- `device` is the logical device that owns the buffer.

- `buffer` is the buffer to query.

- `pMemoryRequirements` is a pointer to a VkMemoryRequirements structure in which the memory requirements of the buffer object are returned.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `buffer` must be a valid VkBuffer handle

- `pMemoryRequirements` must be a valid pointer to a VkMemoryRequirements structure

- `buffer` must have been created, allocated, or retrieved from `device`

To determine the memory requirements for an image resource which is not created with the `VK_IMAGE_CREATE_DISJOINT_BIT` flag set, call:

    void vkGetImageMemoryRequirements(
        VkDevice                                    device,
        VkImage                                     image,
        VkMemoryRequirements*                       pMemoryRequirements);

- `device` is the logical device that owns the image.

- `image` is the image to query.

- `pMemoryRequirements` is a pointer to a VkMemoryRequirements structure in which the memory requirements of the image object are returned.

Valid Usage

- `image` must not have been created with the `VK_IMAGE_CREATE_DISJOINT_BIT` flag set

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `image` must be a valid VkImage handle

- `pMemoryRequirements` must be a valid pointer to a VkMemoryRequirements structure

- `image` must have been created, allocated, or retrieved from `device`

The `VkMemoryRequirements` structure is defined as:

    typedef struct VkMemoryRequirements {
        VkDeviceSize    size;
        VkDeviceSize    alignment;
        uint32_t        memoryTypeBits;
    } VkMemoryRequirements;

- `size` is the size, in bytes, of the memory allocation required for the resource.

- `alignment` is the alignment, in bytes, of the offset within the allocation required for the resource.

- `memoryTypeBits` is a bitmask and contains one bit set for every supported memory type for the resource. Bit `i` is set if and only if the memory type `i` in the `VkPhysicalDeviceMemoryProperties` structure for the physical device is supported for the resource.

The precise size of images that will be bound to external Android hardware buffer memory is unknown until the memory has been imported or allocated, so applications must not call vkGetImageMemoryRequirements with such an image before it has been bound to memory. When importing Android hardware buffer memory, the `allocationSize` can be determined by calling vkGetAndroidHardwareBufferPropertiesANDROID. When allocating new memory for an image that can be exported to an Android hardware buffer, the memory’s `allocationSize` must be zero; the actual size will be determined by the dedicated image’s parameters. After the memory has been allocated, the amount of space allocated from the memory’s heap can be obtained by getting the image’s memory requirements or by calling vkGetAndroidHardwareBufferPropertiesANDROID with the Android hardware buffer exported from the memory.

The implementation guarantees certain properties about the memory requirements returned by vkGetBufferMemoryRequirements and vkGetImageMemoryRequirements:

- The `memoryTypeBits` member always contains at least one bit set.

- If `buffer` is a `VkBuffer` not created with the `VK_BUFFER_CREATE_SPARSE_BINDING_BIT` bit set, or if `image` is linear image, then the `memoryTypeBits` member always contains at least one bit set corresponding to a `VkMemoryType` with a `propertyFlags` that has both the `VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT` bit and the `VK_MEMORY_PROPERTY_HOST_COHERENT_BIT` bit set. In other words, mappable coherent memory can always be attached to these objects.

- If `buffer` was created with VkExternalMemoryBufferCreateInfo::`handleTypes` set to `0` or `image` was created with VkExternalMemoryImageCreateInfo::`handleTypes` set to `0`, the `memoryTypeBits` member always contains at least one bit set corresponding to a `VkMemoryType` with a `propertyFlags` that has the `VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT` bit set.

- The `memoryTypeBits` member is identical for all `VkBuffer` objects created with the same value for the `flags` and `usage` members in the `VkBufferCreateInfo` structure and the `handleTypes` member of the VkExternalMemoryBufferCreateInfo structure passed to `vkCreateBuffer`. Further, if `usage1` and `usage2` of type VkBufferUsageFlags are such that the bits set in `usage2` are a subset of the bits set in `usage1`, and they have the same `flags` and VkExternalMemoryBufferCreateInfo::`handleTypes`, then the bits set in `memoryTypeBits` returned for `usage1` must be a subset of the bits set in `memoryTypeBits` returned for `usage2`, for all values of `flags`.

- The `alignment` member is a power of two.

- The `alignment` member is identical for all `VkBuffer` objects created with the same combination of values for the `usage` and `flags` members in the `VkBufferCreateInfo` structure passed to `vkCreateBuffer`.

- The `alignment` member satisfies the buffer descriptor offset alignment requirements associated with the `VkBuffer`’s `usage`:

  - If `usage` included `VK_BUFFER_USAGE_UNIFORM_TEXEL_BUFFER_BIT` or `VK_BUFFER_USAGE_STORAGE_TEXEL_BUFFER_BIT`, `alignment` must be an integer multiple of `VkPhysicalDeviceLimits`::`minTexelBufferOffsetAlignment`.

  - If `usage` included `VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT`, `alignment` must be an integer multiple of `VkPhysicalDeviceLimits`::`minUniformBufferOffsetAlignment`.

  - If `usage` included `VK_BUFFER_USAGE_STORAGE_BUFFER_BIT`, `alignment` must be an integer multiple of `VkPhysicalDeviceLimits`::`minStorageBufferOffsetAlignment`.

- For images created with a color format, the `memoryTypeBits` member is identical for all `VkImage` objects created with the same combination of values for the `tiling` member, the `VK_IMAGE_CREATE_SPARSE_BINDING_BIT` bit of the `flags` member, the `VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT` bit of the `flags` member, `handleTypes` member of VkExternalMemoryImageCreateInfo, and the `VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT` of the `usage` member in the `VkImageCreateInfo` structure passed to `vkCreateImage`.

- For images created with a depth/stencil format, the `memoryTypeBits` member is identical for all `VkImage` objects created with the same combination of values for the `format` member, the `tiling` member, the `VK_IMAGE_CREATE_SPARSE_BINDING_BIT` bit of the `flags` member, the `VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT` bit of the `flags` member, `handleTypes` member of VkExternalMemoryImageCreateInfo, and the `VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT` of the `usage` member in the `VkImageCreateInfo` structure passed to `vkCreateImage`.

- If the memory requirements are for a `VkImage`, the `memoryTypeBits` member must not refer to a `VkMemoryType` with a `propertyFlags` that has the `VK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BIT` bit set if the `image` did not have `VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT` bit set in the `usage` member of the `VkImageCreateInfo` structure passed to `vkCreateImage`.

- If the memory requirements are for a `VkBuffer`, the `memoryTypeBits` member must not refer to a `VkMemoryType` with a `propertyFlags` that has the `VK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BIT` bit set.

  | Note The implication of this requirement is that lazily allocated memory is disallowed for buffers in all cases.

- The `size` member is identical for all `VkBuffer` objects created with the same combination of creation parameters specified in `VkBufferCreateInfo` and its `pNext` chain.

- The `size` member is identical for all `VkImage` objects created with the same combination of creation parameters specified in `VkImageCreateInfo` and its `pNext` chain.

  | Note This, however, does not imply that they interpret the contents of the bound memory identically with each other. That additional guarantee, however, can be explicitly requested using `VK_IMAGE_CREATE_ALIAS_BIT`.

To determine the memory requirements for a buffer resource, call:

    void vkGetBufferMemoryRequirements2(
        VkDevice                                    device,
        const VkBufferMemoryRequirementsInfo2*      pInfo,
        VkMemoryRequirements2*                      pMemoryRequirements);

or the equivalent command

    void vkGetBufferMemoryRequirements2KHR(
        VkDevice                                    device,
        const VkBufferMemoryRequirementsInfo2*      pInfo,
        VkMemoryRequirements2*                      pMemoryRequirements);

- `device` is the logical device that owns the buffer.

- `pInfo` is a pointer to a `VkBufferMemoryRequirementsInfo2` structure containing parameters required for the memory requirements query.

- `pMemoryRequirements` is a pointer to a VkMemoryRequirements2 structure in which the memory requirements of the buffer object are returned.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pInfo` must be a valid pointer to a valid VkBufferMemoryRequirementsInfo2 structure

- `pMemoryRequirements` must be a valid pointer to a VkMemoryRequirements2 structure

The `VkBufferMemoryRequirementsInfo2` structure is defined as:

    typedef struct VkBufferMemoryRequirementsInfo2 {
        VkStructureType    sType;
        const void*        pNext;
        VkBuffer           buffer;
    } VkBufferMemoryRequirementsInfo2;

or the equivalent

    typedef VkBufferMemoryRequirementsInfo2 VkBufferMemoryRequirementsInfo2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `buffer` is the buffer to query.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_BUFFER_MEMORY_REQUIREMENTS_INFO_2`

- `pNext` must be `NULL`

- `buffer` must be a valid VkBuffer handle

To determine the memory requirements for an image resource, call:

    void vkGetImageMemoryRequirements2(
        VkDevice                                    device,
        const VkImageMemoryRequirementsInfo2*       pInfo,
        VkMemoryRequirements2*                      pMemoryRequirements);

or the equivalent command

    void vkGetImageMemoryRequirements2KHR(
        VkDevice                                    device,
        const VkImageMemoryRequirementsInfo2*       pInfo,
        VkMemoryRequirements2*                      pMemoryRequirements);

- `device` is the logical device that owns the image.

- `pInfo` is a pointer to a `VkImageMemoryRequirementsInfo2` structure containing parameters required for the memory requirements query.

- `pMemoryRequirements` is a pointer to a VkMemoryRequirements2 structure in which the memory requirements of the image object are returned.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pInfo` must be a valid pointer to a valid VkImageMemoryRequirementsInfo2 structure

- `pMemoryRequirements` must be a valid pointer to a VkMemoryRequirements2 structure

The `VkImageMemoryRequirementsInfo2` structure is defined as:

    typedef struct VkImageMemoryRequirementsInfo2 {
        VkStructureType    sType;
        const void*        pNext;
        VkImage            image;
    } VkImageMemoryRequirementsInfo2;

or the equivalent

    typedef VkImageMemoryRequirementsInfo2 VkImageMemoryRequirementsInfo2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `image` is the image to query.

Valid Usage

- If `image` was created with a multi-planar format and the `VK_IMAGE_CREATE_DISJOINT_BIT` flag, there must be a VkImagePlaneMemoryRequirementsInfo included in the `pNext` chain of the VkImageMemoryRequirementsInfo2 structure

- If `image` was created with `VK_IMAGE_CREATE_DISJOINT_BIT` and with `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`, then there must be a VkImagePlaneMemoryRequirementsInfo included in the `pNext` chain of the VkImageMemoryRequirementsInfo2 structure

- If `image` was not created with the `VK_IMAGE_CREATE_DISJOINT_BIT` flag, there must not be a VkImagePlaneMemoryRequirementsInfo included in the `pNext` chain of the VkImageMemoryRequirementsInfo2 structure

- If `image` was created with a single-plane format and with any `tiling` other than `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`, then there must not be a VkImagePlaneMemoryRequirementsInfo included in the `pNext` chain of the VkImageMemoryRequirementsInfo2 structure

- If `image` was created with the `VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID` external memory handle type, then `image` must be bound to memory.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMAGE_MEMORY_REQUIREMENTS_INFO_2`

- `pNext` must be `NULL` or a pointer to a valid instance of VkImagePlaneMemoryRequirementsInfo

- The `sType` value of each struct in the `pNext` chain must be unique

- `image` must be a valid VkImage handle

To determine the memory requirements for a plane of a disjoint image, add a `VkImagePlaneMemoryRequirementsInfo` structure to the `pNext` chain of the `VkImageMemoryRequirementsInfo2` structure.

The `VkImagePlaneMemoryRequirementsInfo` structure is defined as:

    typedef struct VkImagePlaneMemoryRequirementsInfo {
        VkStructureType          sType;
        const void*              pNext;
        VkImageAspectFlagBits    planeAspect;
    } VkImagePlaneMemoryRequirementsInfo;

or the equivalent

    typedef VkImagePlaneMemoryRequirementsInfo VkImagePlaneMemoryRequirementsInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `planeAspect` is the aspect corresponding to the image plane to query.

Valid Usage

- If the image’s tiling is `VK_IMAGE_TILING_LINEAR` or `VK_IMAGE_TILING_OPTIMAL`, then `planeAspect` must be a single valid format plane for the image. (That is, for a two-plane image `planeAspect` must be `VK_IMAGE_ASPECT_PLANE_0_BIT` or `VK_IMAGE_ASPECT_PLANE_1_BIT`, and for a three-plane image `planeAspect` must be `VK_IMAGE_ASPECT_PLANE_0_BIT`, `VK_IMAGE_ASPECT_PLANE_1_BIT` or `VK_IMAGE_ASPECT_PLANE_2_BIT`).

- If the image’s tiling is `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`, then `planeAspect` must be a single valid memory plane for the image. (That is, `aspectMask` must specify a plane index that is less than the `drmFormatModifierPlaneCount` associated with the image’s `format` and `drmFormatModifier`.)

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMAGE_PLANE_MEMORY_REQUIREMENTS_INFO`

- `planeAspect` must be a valid VkImageAspectFlagBits value

The `VkMemoryRequirements2` structure is defined as:

    typedef struct VkMemoryRequirements2 {
        VkStructureType         sType;
        void*                   pNext;
        VkMemoryRequirements    memoryRequirements;
    } VkMemoryRequirements2;

or the equivalent

    typedef VkMemoryRequirements2 VkMemoryRequirements2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `memoryRequirements` is a VkMemoryRequirements structure describing the memory requirements of the resource.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_MEMORY_REQUIREMENTS_2`

- `pNext` must be `NULL` or a pointer to a valid instance of VkMemoryDedicatedRequirements

- The `sType` value of each struct in the `pNext` chain must be unique

To determine the dedicated allocation requirements of a buffer or image resource, add a VkMemoryDedicatedRequirements structure to the `pNext` chain of the VkMemoryRequirements2 structure passed as the `pMemoryRequirements` parameter of `vkGetBufferMemoryRequirements2` or `vkGetImageMemoryRequirements2`.

The `VkMemoryDedicatedRequirements` structure is defined as:

    typedef struct VkMemoryDedicatedRequirements {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           prefersDedicatedAllocation;
        VkBool32           requiresDedicatedAllocation;
    } VkMemoryDedicatedRequirements;

or the equivalent

    typedef VkMemoryDedicatedRequirements VkMemoryDedicatedRequirementsKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `prefersDedicatedAllocation` specifies that the implementation would prefer a dedicated allocation for this resource. The application is still free to suballocate the resource but it may get better performance if a dedicated allocation is used.

- `requiresDedicatedAllocation` specifies that a dedicated allocation is required for this resource.

When the implementation sets `requiresDedicatedAllocation` to `VK_TRUE`, it must also set `prefersDedicatedAllocation` to `VK_TRUE`.

If the `VkMemoryDedicatedRequirements` structure is included in the `pNext` chain of the VkMemoryRequirements2 structure passed as the `pMemoryRequirements` parameter of a `vkGetBufferMemoryRequirements2` call, `requiresDedicatedAllocation` may be `VK_TRUE` under one of the following conditions:

- The `pNext` chain of `VkBufferCreateInfo` for the call to `vkCreateBuffer` used to create the buffer being queried included a `VkExternalMemoryBufferCreateInfo` structure, and any of the handle types specified in `VkExternalMemoryBufferCreateInfo`::`handleTypes` requires dedicated allocation, as reported by vkGetPhysicalDeviceExternalBufferProperties in `VkExternalBufferProperties`::`externalMemoryProperties.externalMemoryFeatures`, the `requiresDedicatedAllocation` field will be set to `VK_TRUE`.

In all other cases, `requiresDedicatedAllocation` must be set to `VK_FALSE` by the implementation whenever a `VkMemoryDedicatedRequirements` structure is included in the `pNext` chain of the `VkMemoryRequirements2` structure passed to a call to `vkGetBufferMemoryRequirements2`.

If the `VkMemoryDedicatedRequirements` structure is included in the `pNext` chain of the `VkMemoryRequirements2` structure passed as the `pMemoryRequirements` parameter of a `vkGetBufferMemoryRequirements2` call and `VK_BUFFER_CREATE_SPARSE_BINDING_BIT` was set in `VkBufferCreateInfo`::`flags` when `buffer` was created then the implementation must set both `prefersDedicatedAllocation` and `requiresDedicatedAllocation` to `VK_FALSE`.

If the `VkMemoryDedicatedRequirements` structure is included in the `pNext` chain of the `VkMemoryRequirements2` structure passed as the `pMemoryRequirements` parameter of a `vkGetImageMemoryRequirements2` call, `requiresDedicatedAllocation` may be `VK_TRUE` under one of the following conditions:

- The `pNext` chain of `VkImageCreateInfo` for the call to `vkCreateImage` used to create the image being queried included a `VkExternalMemoryImageCreateInfo` structure, and any of the handle types specified in `VkExternalMemoryImageCreateInfo`::`handleTypes` requires dedicated allocation, as reported by vkGetPhysicalDeviceImageFormatProperties2 in `VkExternalImageFormatProperties`::`externalMemoryProperties.externalMemoryFeatures`, the `requiresDedicatedAllocation` field will be set to `VK_TRUE`.

In all other cases, `requiresDedicatedAllocation` must be set to `VK_FALSE` by the implementation whenever a `VkMemoryDedicatedRequirements` structure is included in the `pNext` chain of the `VkMemoryRequirements2` structure passed to a call to `vkGetImageMemoryRequirements2`.

If the `VkMemoryDedicatedRequirements` structure is included in the `pNext` chain of the `VkMemoryRequirements2` structure passed as the `pMemoryRequirements` parameter of a `vkGetImageMemoryRequirements2` call and `VK_IMAGE_CREATE_SPARSE_BINDING_BIT` was set in `VkImageCreateInfo`::`flags` when `image` was created then the implementation must set both `prefersDedicatedAllocation` and `requiresDedicatedAllocation` to `VK_FALSE`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_MEMORY_DEDICATED_REQUIREMENTS`

To attach memory to a buffer object, call:

    VkResult vkBindBufferMemory(
        VkDevice                                    device,
        VkBuffer                                    buffer,
        VkDeviceMemory                              memory,
        VkDeviceSize                                memoryOffset);

- `device` is the logical device that owns the buffer and memory.

- `buffer` is the buffer to be attached to memory.

- `memory` is a VkDeviceMemory object describing the device memory to attach.

- `memoryOffset` is the start offset of the region of `memory` which is to be bound to the buffer. The number of bytes returned in the `VkMemoryRequirements`::`size` member in `memory`, starting from `memoryOffset` bytes, will be bound to the specified buffer.

`vkBindBufferMemory` is equivalent to passing the same parameters through VkBindBufferMemoryInfo to vkBindBufferMemory2.

Valid Usage

- `buffer` must not already be backed by a memory object

- `buffer` must not have been created with any sparse memory binding flags

- `memoryOffset` must be less than the size of `memory`

- `memory` must have been allocated using one of the memory types allowed in the `memoryTypeBits` member of the `VkMemoryRequirements` structure returned from a call to `vkGetBufferMemoryRequirements` with `buffer`

- `memoryOffset` must be an integer multiple of the `alignment` member of the `VkMemoryRequirements` structure returned from a call to `vkGetBufferMemoryRequirements` with `buffer`

- The `size` member of the `VkMemoryRequirements` structure returned from a call to `vkGetBufferMemoryRequirements` with `buffer` must be less than or equal to the size of `memory` minus `memoryOffset`

- If `buffer` requires a dedicated allocation(as reported by vkGetBufferMemoryRequirements2 in VkMemoryDedicatedRequirements::requiresDedicatedAllocation for `buffer`), `memory` must have been created with VkMemoryDedicatedAllocateInfo::`buffer` equal to `buffer`

- If the `VkMemoryAllocateInfo` provided when `memory` was allocated included a VkMemoryDedicatedAllocateInfo structure in its `pNext` chain, and VkMemoryDedicatedAllocateInfo::`buffer` was not VK_NULL_HANDLE, then `buffer` must equal VkMemoryDedicatedAllocateInfo::`buffer`, and `memoryOffset` must be zero.

- If buffer was created with the `VK_BUFFER_CREATE_PROTECTED_BIT` bit set, the buffer must be bound to a memory object allocated with a memory type that reports `VK_MEMORY_PROPERTY_PROTECTED_BIT`

- If buffer was created with the `VK_BUFFER_CREATE_PROTECTED_BIT` bit not set, the buffer must not be bound to a memory object created with a memory type that reports `VK_MEMORY_PROPERTY_PROTECTED_BIT`

- If `buffer` was created with VkDedicatedAllocationBufferCreateInfoNV::`dedicatedAllocation` equal to `VK_TRUE`, `memory` must have been created with VkDedicatedAllocationMemoryAllocateInfoNV::`buffer` equal to a buffer handle created with identical creation parameters to `buffer` and `memoryOffset` must be zero

- If the value of VkExportMemoryAllocateInfo::`handleTypes` used to allocate `memory` is not `0`, it must include at least one of the handles set in VkExternalMemoryBufferCreateInfo::`handleTypes` when `buffer` was created

- If `memory` was created by a memory import operation, the external handle type of the imported memory must also have been set in VkExternalMemoryBufferCreateInfo::`handleTypes` when `buffer` was created

- If the VkPhysicalDeviceBufferDeviceAddressFeatures::`bufferDeviceAddress` feature is enabled and `buffer` was created with the `VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT` bit set, `memory` must have been allocated with the `VK_MEMORY_ALLOCATE_DEVICE_ADDRESS_BIT` bit set

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `buffer` must be a valid VkBuffer handle

- `memory` must be a valid VkDeviceMemory handle

- `buffer` must have been created, allocated, or retrieved from `device`

- `memory` must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `buffer` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_INVALID_OPAQUE_CAPTURE_ADDRESS_KHR`

To attach memory to buffer objects for one or more buffers at a time, call:

    VkResult vkBindBufferMemory2(
        VkDevice                                    device,
        uint32_t                                    bindInfoCount,
        const VkBindBufferMemoryInfo*               pBindInfos);

or the equivalent command

    VkResult vkBindBufferMemory2KHR(
        VkDevice                                    device,
        uint32_t                                    bindInfoCount,
        const VkBindBufferMemoryInfo*               pBindInfos);

- `device` is the logical device that owns the buffers and memory.

- `bindInfoCount` is the number of elements in `pBindInfos`.

- `pBindInfos` is a pointer to an array of `bindInfoCount` VkBindBufferMemoryInfo structures describing buffers and memory to bind.

On some implementations, it may be more efficient to batch memory bindings into a single command.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pBindInfos` must be a valid pointer to an array of `bindInfoCount` valid VkBindBufferMemoryInfo structures

- `bindInfoCount` must be greater than `0`

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_INVALID_OPAQUE_CAPTURE_ADDRESS_KHR`

`VkBindBufferMemoryInfo` contains members corresponding to the parameters of vkBindBufferMemory.

The `VkBindBufferMemoryInfo` structure is defined as:

    typedef struct VkBindBufferMemoryInfo {
        VkStructureType    sType;
        const void*        pNext;
        VkBuffer           buffer;
        VkDeviceMemory     memory;
        VkDeviceSize       memoryOffset;
    } VkBindBufferMemoryInfo;

or the equivalent

    typedef VkBindBufferMemoryInfo VkBindBufferMemoryInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `buffer` is the buffer to be attached to memory.

- `memory` is a VkDeviceMemory object describing the device memory to attach.

- `memoryOffset` is the start offset of the region of `memory` which is to be bound to the buffer. The number of bytes returned in the `VkMemoryRequirements`::`size` member in `memory`, starting from `memoryOffset` bytes, will be bound to the specified buffer.

Valid Usage

- `buffer` must not already be backed by a memory object

- `buffer` must not have been created with any sparse memory binding flags

- `memoryOffset` must be less than the size of `memory`

- `memory` must have been allocated using one of the memory types allowed in the `memoryTypeBits` member of the `VkMemoryRequirements` structure returned from a call to `vkGetBufferMemoryRequirements` with `buffer`

- `memoryOffset` must be an integer multiple of the `alignment` member of the `VkMemoryRequirements` structure returned from a call to `vkGetBufferMemoryRequirements` with `buffer`

- The `size` member of the `VkMemoryRequirements` structure returned from a call to `vkGetBufferMemoryRequirements` with `buffer` must be less than or equal to the size of `memory` minus `memoryOffset`

- If `buffer` requires a dedicated allocation(as reported by vkGetBufferMemoryRequirements2 in VkMemoryDedicatedRequirements::requiresDedicatedAllocation for `buffer`), `memory` must have been created with VkMemoryDedicatedAllocateInfo::`buffer` equal to `buffer` and `memoryOffset` must be zero

- If the `VkMemoryAllocateInfo` provided when `memory` was allocated included a VkMemoryDedicatedAllocateInfo structure in its `pNext` chain, and VkMemoryDedicatedAllocateInfo::`buffer` was not VK_NULL_HANDLE, then `buffer` must equal VkMemoryDedicatedAllocateInfo::`buffer` and `memoryOffset` must be zero.

- If `buffer` was created with VkDedicatedAllocationBufferCreateInfoNV::`dedicatedAllocation` equal to `VK_TRUE`, `memory` must have been created with VkDedicatedAllocationMemoryAllocateInfoNV::`buffer` equal to `buffer` and `memoryOffset` must be zero

- If the `pNext` chain includes a VkBindBufferMemoryDeviceGroupInfo structure, all instances of `memory` specified by VkBindBufferMemoryDeviceGroupInfo::`pDeviceIndices` must have been allocated

- If the value of VkExportMemoryAllocateInfo::`handleTypes` used to allocate `memory` is not `0`, it must include at least one of the handles set in VkExternalMemoryBufferCreateInfo::`handleTypes` when `buffer` was created

- If `memory` was created by a memory import operation, the external handle type of the imported memory must also have been set in VkExternalMemoryBufferCreateInfo::`handleTypes` when `buffer` was created

- If the VkPhysicalDeviceBufferDeviceAddressFeaturesKHR::`bufferDeviceAddress` feature is enabled and `buffer` was created with the `VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT_KHR` bit set, `memory` must have been allocated with the `VK_MEMORY_ALLOCATE_DEVICE_ADDRESS_BIT_KHR` bit set

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_BIND_BUFFER_MEMORY_INFO`

- `pNext` must be `NULL` or a pointer to a valid instance of VkBindBufferMemoryDeviceGroupInfo

- The `sType` value of each struct in the `pNext` chain must be unique

- `buffer` must be a valid VkBuffer handle

- `memory` must be a valid VkDeviceMemory handle

- Both of `buffer`, and `memory` must have been created, allocated, or retrieved from the same VkDevice

    typedef struct VkBindBufferMemoryDeviceGroupInfo {
        VkStructureType    sType;
        const void*        pNext;
        uint32_t           deviceIndexCount;
        const uint32_t*    pDeviceIndices;
    } VkBindBufferMemoryDeviceGroupInfo;

or the equivalent

    typedef VkBindBufferMemoryDeviceGroupInfo VkBindBufferMemoryDeviceGroupInfoKHR;

If the `pNext` list of VkBindBufferMemoryInfo includes a `VkBindBufferMemoryDeviceGroupInfo` structure, then that structure determines how memory is bound to buffers across multiple devices in a device group.

The `VkBindBufferMemoryDeviceGroupInfo` structure is defined as:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `deviceIndexCount` is the number of elements in `pDeviceIndices`.

- `pDeviceIndices` is a pointer to an array of device indices.

If `deviceIndexCount` is greater than zero, then on device index i the buffer is attached to the instance of `memory` on the physical device with device index pDeviceIndices[i].

If `deviceIndexCount` is zero and `memory` comes from a memory heap with the `VK_MEMORY_HEAP_MULTI_INSTANCE_BIT` bit set, then it is as if `pDeviceIndices` contains consecutive indices from zero to the number of physical devices in the logical device, minus one. In other words, by default each physical device attaches to its own instance of `memory`.

If `deviceIndexCount` is zero and `memory` comes from a memory heap without the `VK_MEMORY_HEAP_MULTI_INSTANCE_BIT` bit set, then it is as if `pDeviceIndices` contains an array of zeros. In other words, by default each physical device attaches to instance zero.

Valid Usage

- `deviceIndexCount` must either be zero or equal to the number of physical devices in the logical device

- All elements of `pDeviceIndices` must be valid device indices

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_BIND_BUFFER_MEMORY_DEVICE_GROUP_INFO`

- If `deviceIndexCount` is not `0`, `pDeviceIndices` must be a valid pointer to an array of `deviceIndexCount` `uint32_t` values

To attach memory to a `VkImage` object created without the `VK_IMAGE_CREATE_DISJOINT_BIT` set, call:

    VkResult vkBindImageMemory(
        VkDevice                                    device,
        VkImage                                     image,
        VkDeviceMemory                              memory,
        VkDeviceSize                                memoryOffset);

- `device` is the logical device that owns the image and memory.

- `image` is the image.

- `memory` is the VkDeviceMemory object describing the device memory to attach.

- `memoryOffset` is the start offset of the region of `memory` which is to be bound to the image. The number of bytes returned in the `VkMemoryRequirements`::`size` member in `memory`, starting from `memoryOffset` bytes, will be bound to the specified image.

`vkBindImageMemory` is equivalent to passing the same parameters through VkBindImageMemoryInfo to vkBindImageMemory2.

Valid Usage

- `image` must not have been created with the `VK_IMAGE_CREATE_DISJOINT_BIT` set.

- `image` must not already be backed by a memory object

- `image` must not have been created with any sparse memory binding flags

- `memoryOffset` must be less than the size of `memory`

- `memory` must have been allocated using one of the memory types allowed in the `memoryTypeBits` member of the `VkMemoryRequirements` structure returned from a call to `vkGetImageMemoryRequirements` with `image`

- `memoryOffset` must be an integer multiple of the `alignment` member of the `VkMemoryRequirements` structure returned from a call to `vkGetImageMemoryRequirements` with `image`

- The difference of the size of `memory` and `memoryOffset` must be greater than or equal to the `size` member of the VkMemoryRequirements structure returned from a call to vkGetImageMemoryRequirements with the same `image`

- If `image` requires a dedicated allocation (as reported by vkGetImageMemoryRequirements2 in VkMemoryDedicatedRequirements::requiresDedicatedAllocation for `image`), `memory` must have been created with VkMemoryDedicatedAllocateInfo::`image` equal to `image`

- If the dedicated allocation image aliasing feature is not enabled, and the `VkMemoryAllocateInfo` provided when `memory` was allocated included a VkMemoryDedicatedAllocateInfo structure in its `pNext` chain, and VkMemoryDedicatedAllocateInfo::`image` was not VK_NULL_HANDLE, then `image` must equal VkMemoryDedicatedAllocateInfo::`image` and `memoryOffset` must be zero.

- If the dedicated allocation image aliasing feature is enabled, and the `VkMemoryAllocateInfo` provided when `memory` was allocated included a VkMemoryDedicatedAllocateInfo structure in its `pNext` chain, and VkMemoryDedicatedAllocateInfo::`image` was not VK_NULL_HANDLE, then `memoryOffset` must be zero, and `image` must be either equal to VkMemoryDedicatedAllocateInfo::`image` or an image that was created using the same parameters in `VkImageCreateInfo`, with the exception that `extent` and `arrayLayers` may differ subject to the following restrictions: every dimension in the `extent` parameter of the image being bound must be equal to or smaller than the original image for which the allocation was created; and the `arrayLayers` parameter of the image being bound must be equal to or smaller than the original image for which the allocation was created.

- If image was created with the `VK_IMAGE_CREATE_PROTECTED_BIT` bit set, the image must be bound to a memory object allocated with a memory type that reports `VK_MEMORY_PROPERTY_PROTECTED_BIT`

- If image was created with the `VK_IMAGE_CREATE_PROTECTED_BIT` bit not set, the image must not be bound to a memory object created with a memory type that reports `VK_MEMORY_PROPERTY_PROTECTED_BIT`

- If `image` was created with VkDedicatedAllocationImageCreateInfoNV::`dedicatedAllocation` equal to `VK_TRUE`, `memory` must have been created with VkDedicatedAllocationMemoryAllocateInfoNV::`image` equal to an image handle created with identical creation parameters to `image` and `memoryOffset` must be zero

- If the value of VkExportMemoryAllocateInfo::`handleTypes` used to allocate `memory` is not `0`, it must include at least one of the handles set in VkExternalMemoryImageCreateInfo::`handleTypes` when `image` was created

- If `memory` was created by a memory import operation, the external handle type of the imported memory must also have been set in VkExternalMemoryImageCreateInfo::`handleTypes` when `image` was created

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `image` must be a valid VkImage handle

- `memory` must be a valid VkDeviceMemory handle

- `image` must have been created, allocated, or retrieved from `device`

- `memory` must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `image` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

To attach memory to image objects for one or more images at a time, call:

    VkResult vkBindImageMemory2(
        VkDevice                                    device,
        uint32_t                                    bindInfoCount,
        const VkBindImageMemoryInfo*                pBindInfos);

or the equivalent command

    VkResult vkBindImageMemory2KHR(
        VkDevice                                    device,
        uint32_t                                    bindInfoCount,
        const VkBindImageMemoryInfo*                pBindInfos);

- `device` is the logical device that owns the images and memory.

- `bindInfoCount` is the number of elements in `pBindInfos`.

- `pBindInfos` is a pointer to an array of VkBindImageMemoryInfo structures, describing images and memory to bind.

On some implementations, it may be more efficient to batch memory bindings into a single command.

Valid Usage

- If any VkBindImageMemoryInfo::image was created with `VK_IMAGE_CREATE_DISJOINT_BIT` then all planes of VkBindImageMemoryInfo::image must be bound individually in separate `pBindInfos`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pBindInfos` must be a valid pointer to an array of `bindInfoCount` valid VkBindImageMemoryInfo structures

- `bindInfoCount` must be greater than `0`

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

`VkBindImageMemoryInfo` contains members corresponding to the parameters of vkBindImageMemory.

The `VkBindImageMemoryInfo` structure is defined as:

    typedef struct VkBindImageMemoryInfo {
        VkStructureType    sType;
        const void*        pNext;
        VkImage            image;
        VkDeviceMemory     memory;
        VkDeviceSize       memoryOffset;
    } VkBindImageMemoryInfo;

or the equivalent

    typedef VkBindImageMemoryInfo VkBindImageMemoryInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `image` is the image to be attached to memory.

- `memory` is a VkDeviceMemory object describing the device memory to attach.

- `memoryOffset` is the start offset of the region of `memory` which is to be bound to the image. The number of bytes returned in the `VkMemoryRequirements`::`size` member in `memory`, starting from `memoryOffset` bytes, will be bound to the specified image.

Valid Usage

- `image` must not already be backed by a memory object

- `image` must not have been created with any sparse memory binding flags

- `memoryOffset` must be less than the size of `memory`

- If the `pNext` chain does not include a VkBindImagePlaneMemoryInfo structure, `memory` must have been allocated using one of the memory types allowed in the `memoryTypeBits` member of the VkMemoryRequirements structure returned from a call to vkGetImageMemoryRequirements2 with `image`

- If the `pNext` chain does not include a VkBindImagePlaneMemoryInfo structure, `memoryOffset` must be an integer multiple of the `alignment` member of the VkMemoryRequirements structure returned from a call to vkGetImageMemoryRequirements2 with `image`

- If the `pNext` chain does not include a VkBindImagePlaneMemoryInfo structure, the difference of the size of `memory` and `memoryOffset` must be greater than or equal to the `size` member of the VkMemoryRequirements structure returned from a call to vkGetImageMemoryRequirements2 with the same `image`

- If the `pNext` chain includes a VkBindImagePlaneMemoryInfo structure, `image` must have been created with the `VK_IMAGE_CREATE_DISJOINT_BIT` bit set.

- If the `pNext` chain includes a VkBindImagePlaneMemoryInfo structure, `memory` must have been allocated using one of the memory types allowed in the `memoryTypeBits` member of the VkMemoryRequirements structure returned from a call to vkGetImageMemoryRequirements2 with `image` and where VkBindImagePlaneMemoryInfo::`planeAspect` corresponds to the VkImagePlaneMemoryRequirementsInfo::`planeAspect` in the VkImageMemoryRequirementsInfo2 structure’s `pNext` chain

- If the `pNext` chain includes a VkBindImagePlaneMemoryInfo structure, `memoryOffset` must be an integer multiple of the `alignment` member of the VkMemoryRequirements structure returned from a call to vkGetImageMemoryRequirements2 with `image` and where VkBindImagePlaneMemoryInfo::`planeAspect` corresponds to the VkImagePlaneMemoryRequirementsInfo::`planeAspect` in the VkImageMemoryRequirementsInfo2 structure’s `pNext` chain

- If the `pNext` chain includes a VkBindImagePlaneMemoryInfo structure, the difference of the size of `memory` and `memoryOffset` must be greater than or equal to the `size` member of the VkMemoryRequirements structure returned from a call to vkGetImageMemoryRequirements2 with the same `image` and where VkBindImagePlaneMemoryInfo::`planeAspect` corresponds to the VkImagePlaneMemoryRequirementsInfo::`planeAspect` in the VkImageMemoryRequirementsInfo2 structure’s `pNext` chain

- If `image` requires a dedicated allocation (as reported by vkGetImageMemoryRequirements2 in VkMemoryDedicatedRequirements::requiresDedicatedAllocation for `image`), `memory` must have been created with VkMemoryDedicatedAllocateInfo::`image` equal to `image` and `memoryOffset` must be zero

- If the dedicated allocation image aliasing feature is not enabled, and the `VkMemoryAllocateInfo` provided when `memory` was allocated included a VkMemoryDedicatedAllocateInfo structure in its `pNext` chain, and VkMemoryDedicatedAllocateInfo::`image` was not VK_NULL_HANDLE, then `image` must equal VkMemoryDedicatedAllocateInfo::`image` and `memoryOffset` must be zero.

- If the dedicated allocation image aliasing feature is enabled, and the `VkMemoryAllocateInfo` provided when `memory` was allocated included a VkMemoryDedicatedAllocateInfo structure in its `pNext` chain, and VkMemoryDedicatedAllocateInfo::`image` was not VK_NULL_HANDLE, then `memoryOffset` must be zero, and `image` must be either equal to VkMemoryDedicatedAllocateInfo::`image` or an image that was created using the same parameters in `VkImageCreateInfo`, with the exception that `extent` and `arrayLayers` may differ subject to the following restrictions: every dimension in the `extent` parameter of the image being bound must be equal to or smaller than the original image for which the allocation was created; and the `arrayLayers` parameter of the image being bound must be equal to or smaller than the original image for which the allocation was created.

- If `image` was created with VkDedicatedAllocationImageCreateInfoNV::`dedicatedAllocation` equal to `VK_TRUE`, `memory` must have been created with VkDedicatedAllocationMemoryAllocateInfoNV::`image` equal to `image` and `memoryOffset` must be zero

- If the `pNext` chain includes a VkBindImageMemoryDeviceGroupInfo structure, all instances of `memory` specified by VkBindImageMemoryDeviceGroupInfo::`pDeviceIndices` must have been allocated

- If the `pNext` chain includes a VkBindImageMemoryDeviceGroupInfo structure, and VkBindImageMemoryDeviceGroupInfo::`splitInstanceBindRegionCount` is not zero, then `image` must have been created with the `VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT` bit set

- If the `pNext` chain includes a VkBindImageMemoryDeviceGroupInfo structure, all elements of VkBindImageMemoryDeviceGroupInfo::`pSplitInstanceBindRegions` must be valid rectangles contained within the dimensions of `image`

- If the `pNext` chain includes a VkBindImageMemoryDeviceGroupInfo structure, the union of the areas of all elements of VkBindImageMemoryDeviceGroupInfo::`pSplitInstanceBindRegions` that correspond to the same instance of `image` must cover the entire image.

- If `image` was created with a valid swapchain handle in VkImageSwapchainCreateInfoKHR::`swapchain`, then the `pNext` chain must include a VkBindImageMemorySwapchainInfoKHR structure containing the same swapchain handle.

- If the `pNext` chain includes a VkBindImageMemorySwapchainInfoKHR structure, `memory` must be VK_NULL_HANDLE

- If the `pNext` chain does not include a VkBindImageMemorySwapchainInfoKHR structure, `memory` must be a valid VkDeviceMemory handle

- If the value of VkExportMemoryAllocateInfo::`handleTypes` used to allocate `memory` is not `0`, it must include at least one of the handles set in VkExternalMemoryImageCreateInfo::`handleTypes` when `image` was created

- If `memory` was created by a memory import operation, the external handle type of the imported memory must also have been set in VkExternalMemoryImageCreateInfo::`handleTypes` when `image` was created

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_INFO`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkBindImageMemoryDeviceGroupInfo, VkBindImageMemorySwapchainInfoKHR, or VkBindImagePlaneMemoryInfo

- The `sType` value of each struct in the `pNext` chain must be unique

- `image` must be a valid VkImage handle

- Both of `image`, and `memory` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

    typedef struct VkBindImageMemoryDeviceGroupInfo {
        VkStructureType    sType;
        const void*        pNext;
        uint32_t           deviceIndexCount;
        const uint32_t*    pDeviceIndices;
        uint32_t           splitInstanceBindRegionCount;
        const VkRect2D*    pSplitInstanceBindRegions;
    } VkBindImageMemoryDeviceGroupInfo;

or the equivalent

    typedef VkBindImageMemoryDeviceGroupInfo VkBindImageMemoryDeviceGroupInfoKHR;

If the `pNext` list of VkBindImageMemoryInfo includes a `VkBindImageMemoryDeviceGroupInfo` structure, then that structure determines how memory is bound to images across multiple devices in a device group.

The `VkBindImageMemoryDeviceGroupInfo` structure is defined as:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `deviceIndexCount` is the number of elements in `pDeviceIndices`.

- `pDeviceIndices` is a pointer to an array of device indices.

- `splitInstanceBindRegionCount` is the number of elements in `pSplitInstanceBindRegions`.

- `pSplitInstanceBindRegions` is a pointer to an array of VkRect2D structures describing which regions of the image are attached to each instance of memory.

If `deviceIndexCount` is greater than zero, then on device index i `image` is attached to the instance of the memory on the physical device with device index pDeviceIndices[i].

Let N be the number of physical devices in the logical device. If `splitInstanceBindRegionCount` is greater than zero, then `pSplitInstanceBindRegions` is an array of N2 rectangles, where the image region specified by the rectangle at element i*N+j in resource instance i is bound to the memory instance j. The blocks of the memory that are bound to each sparse image block region use an offset in memory, relative to `memoryOffset`, computed as if the whole image were being bound to a contiguous range of memory. In other words, horizontally adjacent image blocks use consecutive blocks of memory, vertically adjacent image blocks are separated by the number of bytes per block multiplied by the width in blocks of `image`, and the block at (0,0) corresponds to memory starting at `memoryOffset`.

If `splitInstanceBindRegionCount` and `deviceIndexCount` are zero and the memory comes from a memory heap with the `VK_MEMORY_HEAP_MULTI_INSTANCE_BIT` bit set, then it is as if `pDeviceIndices` contains consecutive indices from zero to the number of physical devices in the logical device, minus one. In other words, by default each physical device attaches to its own instance of the memory.

If `splitInstanceBindRegionCount` and `deviceIndexCount` are zero and the memory comes from a memory heap without the `VK_MEMORY_HEAP_MULTI_INSTANCE_BIT` bit set, then it is as if `pDeviceIndices` contains an array of zeros. In other words, by default each physical device attaches to instance zero.

Valid Usage

- At least one of `deviceIndexCount` and `splitInstanceBindRegionCount` must be zero.

- `deviceIndexCount` must either be zero or equal to the number of physical devices in the logical device

- All elements of `pDeviceIndices` must be valid device indices.

- `splitInstanceBindRegionCount` must either be zero or equal to the number of physical devices in the logical device squared

- Elements of `pSplitInstanceBindRegions` that correspond to the same instance of an image must not overlap.

- The `offset.x` member of any element of `pSplitInstanceBindRegions` must be a multiple of the sparse image block width (`VkSparseImageFormatProperties`::`imageGranularity.width`) of all non-metadata aspects of the image

- The `offset.y` member of any element of `pSplitInstanceBindRegions` must be a multiple of the sparse image block height (`VkSparseImageFormatProperties`::`imageGranularity.height`) of all non-metadata aspects of the image

- The `extent.width` member of any element of `pSplitInstanceBindRegions` must either be a multiple of the sparse image block width of all non-metadata aspects of the image, or else `extent.width` + `offset.x` must equal the width of the image subresource

- The `extent.height` member of any element of `pSplitInstanceBindRegions` must either be a multiple of the sparse image block height of all non-metadata aspects of the image, or else `extent.height` + `offset.y` must equal the width of the image subresource

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_DEVICE_GROUP_INFO`

- If `deviceIndexCount` is not `0`, `pDeviceIndices` must be a valid pointer to an array of `deviceIndexCount` `uint32_t` values

- If `splitInstanceBindRegionCount` is not `0`, `pSplitInstanceBindRegions` must be a valid pointer to an array of `splitInstanceBindRegionCount` VkRect2D structures

If the `pNext` chain of VkBindImageMemoryInfo includes a `VkBindImageMemorySwapchainInfoKHR` structure, then that structure includes a swapchain handle and image index indicating that the image will be bound to memory from that swapchain.

The `VkBindImageMemorySwapchainInfoKHR` structure is defined as:

    typedef struct VkBindImageMemorySwapchainInfoKHR {
        VkStructureType    sType;
        const void*        pNext;
        VkSwapchainKHR     swapchain;
        uint32_t           imageIndex;
    } VkBindImageMemorySwapchainInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `swapchain` is VK_NULL_HANDLE or a swapchain handle.

- `imageIndex` is an image index within `swapchain`.

If `swapchain` is not `NULL`, the `swapchain` and `imageIndex` are used to determine the memory that the image is bound to, instead of `memory` and `memoryOffset`.

Memory can be bound to a swapchain and use the `pDeviceIndices` or `pSplitInstanceBindRegions` members of VkBindImageMemoryDeviceGroupInfo.

Valid Usage

- `imageIndex` must be less than the number of images in `swapchain`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_SWAPCHAIN_INFO_KHR`

- `swapchain` must be a valid VkSwapchainKHR handle

Host Synchronization

- Host access to `swapchain` must be externally synchronized

In order to bind planes of a disjoint image, add a `VkBindImagePlaneMemoryInfo` structure to the `pNext` chain of VkBindImageMemoryInfo.

The `VkBindImagePlaneMemoryInfo` structure is defined as:

    typedef struct VkBindImagePlaneMemoryInfo {
        VkStructureType          sType;
        const void*              pNext;
        VkImageAspectFlagBits    planeAspect;
    } VkBindImagePlaneMemoryInfo;

or the equivalent

    typedef VkBindImagePlaneMemoryInfo VkBindImagePlaneMemoryInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `planeAspect` is the aspect of the disjoint image plane to bind.

Valid Usage

- If the image’s tiling is `VK_IMAGE_TILING_LINEAR` or `VK_IMAGE_TILING_OPTIMAL`, then `planeAspect` must be a single valid format plane for the image. (That is, `planeAspect` must be `VK_IMAGE_ASPECT_PLANE_0_BIT` or `VK_IMAGE_ASPECT_PLANE_1_BIT` for “`_2PLANE`” formats and `planeAspect` must be `VK_IMAGE_ASPECT_PLANE_0_BIT`, `VK_IMAGE_ASPECT_PLANE_1_BIT`, or `VK_IMAGE_ASPECT_PLANE_2_BIT` for “`_3PLANE`” formats.)

- If the image’s tiling is `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`, then `planeAspect` must be a single valid memory plane for the image. (That is, `aspectMask` must specify a plane index that is less than the `drmFormatModifierPlaneCount` associated with the image’s `format` and `drmFormatModifier`.)

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_BIND_IMAGE_PLANE_MEMORY_INFO`

- `planeAspect` must be a valid VkImageAspectFlagBits value

Buffer-Image Granularity

There is an implementation-dependent limit, `bufferImageGranularity`, which specifies a page-like granularity at which linear and non-linear resources must be placed in adjacent memory locations to avoid aliasing. Two resources which do not satisfy this granularity requirement are said to alias. `bufferImageGranularity` is specified in bytes, and must be a power of two. Implementations which do not impose a granularity restriction may report a `bufferImageGranularity` value of one.

| Note Despite its name, `bufferImageGranularity` is really a granularity between “linear” and “non-linear” resources.

Given resourceA at the lower memory offset and resourceB at the higher memory offset in the same `VkDeviceMemory` object, where one resource is linear and the other is non-linear (as defined in the Glossary), and the following:

    resourceA.end       = resourceA.memoryOffset + resourceA.size - 1
    resourceA.endPage   = resourceA.end & ~(bufferImageGranularity-1)
    resourceB.start     = resourceB.memoryOffset
    resourceB.startPage = resourceB.start & ~(bufferImageGranularity-1)

The following property must hold:

    resourceA.endPage < resourceB.startPage

That is, the end of the first resource (A) and the beginning of the second resource (B) must be on separate “pages” of size `bufferImageGranularity`. `bufferImageGranularity` may be different than the physical page size of the memory heap. This restriction is only needed when a linear resource and a non-linear resource are adjacent in memory and will be used simultaneously. The memory ranges of adjacent resources can be closer than `bufferImageGranularity`, provided they meet the `alignment` requirement for the objects in question.

Sparse block size in bytes and sparse image and buffer memory alignments must all be multiples of the `bufferImageGranularity`. Therefore, memory bound to sparse resources naturally satisfies the `bufferImageGranularity`.

### 11.7. Resource Sharing Mode

Buffer and image objects are created with a sharing mode controlling how they can be accessed from queues. The supported sharing modes are:

    typedef enum VkSharingMode {
        VK_SHARING_MODE_EXCLUSIVE = 0,
        VK_SHARING_MODE_CONCURRENT = 1,
        VK_SHARING_MODE_MAX_ENUM = 0x7FFFFFFF
    } VkSharingMode;

- `VK_SHARING_MODE_EXCLUSIVE` specifies that access to any range or image subresource of the object will be exclusive to a single queue family at a time.

- `VK_SHARING_MODE_CONCURRENT` specifies that concurrent access to any range or image subresource of the object from multiple queue families is supported.

| Note `VK_SHARING_MODE_CONCURRENT` may result in lower performance access to the buffer or image than `VK_SHARING_MODE_EXCLUSIVE`.

Ranges of buffers and image subresources of image objects created using `VK_SHARING_MODE_EXCLUSIVE` must only be accessed by queues in the queue family that has ownership of the resource. Upon creation, such resources are not owned by any queue family; ownership is implicitly acquired upon first use within a queue. Once a resource using `VK_SHARING_MODE_EXCLUSIVE` is owned by some queue family, the application must perform a queue family ownership transfer to make the memory contents of a range or image subresource accessible to a different queue family.

| Note Images still require a layout transition from `VK_IMAGE_LAYOUT_UNDEFINED` or `VK_IMAGE_LAYOUT_PREINITIALIZED` before being used on the first queue.

A queue family can take ownership of an image subresource or buffer range of a resource created with `VK_SHARING_MODE_EXCLUSIVE`, without an ownership transfer, in the same way as for a resource that was just created; however, taking ownership in this way has the effect that the contents of the image subresource or buffer range are undefined.

Ranges of buffers and image subresources of image objects created using `VK_SHARING_MODE_CONCURRENT` must only be accessed by queues from the queue families specified through the `queueFamilyIndexCount` and `pQueueFamilyIndices` members of the corresponding create info structures.

#### 11.7.1. External Resource Sharing

Resources should only be accessed in the Vulkan instance that has exclusive ownership of their underlying memory. Only one Vulkan instance has exclusive ownership of a resource’s underlying memory at a given time, regardless of whether the resource was created using `VK_SHARING_MODE_EXCLUSIVE` or `VK_SHARING_MODE_CONCURRENT`. Applications can transfer ownership of a resource’s underlying memory only if the memory has been imported from or exported to another instance or external API using external memory handles. The semantics for transferring ownership outside of the instance are similar to those used for transferring ownership of `VK_SHARING_MODE_EXCLUSIVE` resources between queues, and is also accomplished using VkBufferMemoryBarrier or VkImageMemoryBarrier operations. Applications must

1. Release exclusive ownership from the source instance or API.

2. Ensure the release operation has completed using semaphores or fences.

3. Acquire exclusive ownership in the destination instance or API

Unlike queue ownership transfers, the destination instance or API is not specified explicitly when releasing ownership, nor is the source instance or API specified when acquiring ownership. Instead, the image or memory barrier’s `dstQueueFamilyIndex` or `srcQueueFamilyIndex` parameters are set to the reserved queue family index `VK_QUEUE_FAMILY_EXTERNAL` or `VK_QUEUE_FAMILY_FOREIGN_EXT` to represent the external destination or source respectively.

Binding a resource to a memory object shared between multiple Vulkan instances or other APIs does not change the ownership of the underlying memory. The first entity to access the resource implicitly acquires ownership. Accessing a resource backed by memory that is owned by a particular instance or API has the same semantics as accessing a `VK_SHARING_MODE_EXCLUSIVE` resource, with one exception: Implementations must ensure layout transitions performed on one member of a set of identical subresources of identical images that alias the same range of an underlying memory object affect the layout of all the subresources in the set.

As a corollary, writes to any image subresources in such a set must not make the contents of memory used by other subresources in the set undefined. An application can define the content of a subresource of one image by performing device writes to an identical subresource of another image provided both images are bound to the same region of external memory. Applications may also add resources to such a set after the content of the existing set members has been defined without making the content undefined by creating a new image with the initial layout `VK_IMAGE_LAYOUT_UNDEFINED` and binding it to the same region of external memory as the existing images.

| Note Because layout transitions apply to all identical images aliasing the same region of external memory, the actual layout of the memory backing a new image as well as an existing image with defined content will not be undefined. Such an image is not usable until it acquires ownership of its memory from the existing owner. Therefore, the layout specified as part of this transition will be the true initial layout of the image. The undefined layout specified when creating it is a placeholder to simplify valid usage requirements.

### 11.8. Memory Aliasing

A range of a `VkDeviceMemory` allocation is aliased if it is bound to multiple resources simultaneously, as described below, via vkBindImageMemory, vkBindBufferMemory, vkBindAccelerationStructureMemoryKHR, vkBindAccelerationStructureMemoryNV, via sparse memory bindings, or by binding the memory to resources in multiple Vulkan instances or external APIs using external memory handle export and import mechanisms.

Consider two resources, resourceA and resourceB, bound respectively to memory rangeA and rangeB. Let paddedRangeA and paddedRangeB be, respectively, rangeA and rangeB aligned to `bufferImageGranularity`. If the resources are both linear or both non-linear (as defined in the Glossary), then the resources alias the memory in the intersection of rangeA and rangeB. If one resource is linear and the other is non-linear, then the resources alias the memory in the intersection of paddedRangeA and paddedRangeB.

Applications can alias memory, but use of multiple aliases is subject to several constraints.

| Note Memory aliasing can be useful to reduce the total device memory footprint of an application, if some large resources are used for disjoint periods of time.

When a non-linear, non-`VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT` image is bound to an aliased range, all image subresources of the image overlap the range. When a linear image is bound to an aliased range, the image subresources that (according to the image’s advertised layout) include bytes from the aliased range overlap the range. When a `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT` image has sparse image blocks bound to an aliased range, only image subresources including those sparse image blocks overlap the range, and when the memory bound to the image’s mip tail overlaps an aliased range all image subresources in the mip tail overlap the range.

Buffers, and linear image subresources in either the `VK_IMAGE_LAYOUT_PREINITIALIZED` or `VK_IMAGE_LAYOUT_GENERAL` layouts, are host-accessible subresources. That is, the host has a well-defined addressing scheme to interpret the contents, and thus the layout of the data in memory can be consistently interpreted across aliases if each of those aliases is a host-accessible subresource. Non-linear images, and linear image subresources in other layouts, are not host-accessible.

If two aliases are both host-accessible, then they interpret the contents of the memory in consistent ways, and data written to one alias can be read by the other alias.

If two aliases are both images that were created with identical creation parameters, both were created with the `VK_IMAGE_CREATE_ALIAS_BIT` flag set, and both are bound identically to memory except for VkBindImageMemoryDeviceGroupInfo::`pDeviceIndices` and VkBindImageMemoryDeviceGroupInfo::`pSplitInstanceBindRegions`, then they interpret the contents of the memory in consistent ways, and data written to one alias can be read by the other alias.

Additionally, if an invididual plane of a multi-planar image and a single-plane image alias the same memory, then they also interpret the contents of the memory in consistent ways under the same conditions, but with the following modifications:

- Both must have been created with the `VK_IMAGE_CREATE_DISJOINT_BIT` flag.

- The single-plane image must have a VkFormat that is equivalent to that of the multi-planar image’s individual plane.

- The single-plane image and the individual plane of the multi-planar image must be bound identically to memory except for VkBindImageMemoryDeviceGroupInfo::`pDeviceIndices` and VkBindImageMemoryDeviceGroupInfo::`pSplitInstanceBindRegions`.

- The `width` and `height` of the single-plane image are derived from the multi-planar image’s dimensions in the manner listed for plane compatibility for the aliased plane.

- If either image’s `tiling` is `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`, then both images must be linear.

- All other creation parameters must be identical

Aliases created by binding the same memory to resources in multiple Vulkan instances or external APIs using external memory handle export and import mechanisms interpret the contents of the memory in consistent ways, and data written to one alias can be read by the other alias.

Otherwise, the aliases interpret the contents of the memory differently, and writes via one alias make the contents of memory partially or completely undefined to the other alias. If the first alias is a host-accessible subresource, then the bytes affected are those written by the memory operations according to its addressing scheme. If the first alias is not host-accessible, then the bytes affected are those overlapped by the image subresources that were written. If the second alias is a host-accessible subresource, the affected bytes become undefined. If the second alias is a not host-accessible, all sparse image blocks (for sparse partially-resident images) or all image subresources (for non-sparse image and fully resident sparse images) that overlap the affected bytes become undefined.

If any image subresources are made undefined due to writes to an alias, then each of those image subresources must have its layout transitioned from `VK_IMAGE_LAYOUT_UNDEFINED` to a valid layout before it is used, or from `VK_IMAGE_LAYOUT_PREINITIALIZED` if the memory has been written by the host. If any sparse blocks of a sparse image have been made undefined, then only the image subresources containing them must be transitioned.

Use of an overlapping range by two aliases must be separated by a memory dependency using the appropriate access types if at least one of those uses performs writes, whether the aliases interpret memory consistently or not. If buffer or image memory barriers are used, the scope of the barrier must contain the entire range and/or set of image subresources that overlap.

If two aliasing image views are used in the same framebuffer, then the render pass must declare the attachments using the `VK_ATTACHMENT_DESCRIPTION_MAY_ALIAS_BIT`, and follow the other rules listed in that section.

| Note Memory recycled via an application suballocator (i.e. without freeing and reallocating the memory objects) is not substantially different from memory aliasing. However, a suballocator usually waits on a fence before recycling a region of memory, and signaling a fence involves sufficient implicit dependencies to satisfy all the above requirements.

### 11.9. Acceleration Structures

Acceleration structures are an opaque structure that is built by the implementation to more efficiently perform spatial queries on the provided geometric data. For this extension, an acceleration structure is either a top-level acceleration structure containing a set of bottom-level acceleration structures or a bottom-level acceleration structure containing either a set of axis-aligned bounding boxes for custom geometry or a set of triangles.

Each instance in the top-level acceleration structure contains a reference to a bottom-level acceleration structure as well as an instance transform plus information required to index into the shader bindings. The top-level acceleration structure is what is bound to the acceleration descriptor to trace inside the shader in the ray tracing pipeline.

Acceleration structures are represented by `VkAccelerationStructureKHR` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkAccelerationStructureKHR)

or the equivalent

    typedef VkAccelerationStructureKHR VkAccelerationStructureNV;

To create acceleration structures, call:

    VkResult vkCreateAccelerationStructureNV(
        VkDevice                                    device,
        const VkAccelerationStructureCreateInfoNV*  pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkAccelerationStructureNV*                  pAccelerationStructure);

- `device` is the logical device that creates the buffer object.

- `pCreateInfo` is a pointer to a VkAccelerationStructureCreateInfoNV structure containing parameters affecting creation of the acceleration structure.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pAccelerationStructure` is a pointer to a VkAccelerationStructureNV handle in which the resulting acceleration structure object is returned.

Similar to other objects in Vulkan, the acceleration structure creation merely creates an object with a specific “shape” as specified by the information in VkAccelerationStructureInfoNV and `compactedSize` in `pCreateInfo`. Populating the data in the object after allocating and binding memory is done with vkCmdBuildAccelerationStructureNV and vkCmdCopyAccelerationStructureNV.

Acceleration structure creation uses the count and type information from the geometries, but does not use the data references in the structures.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkAccelerationStructureCreateInfoNV structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pAccelerationStructure` must be a valid pointer to a VkAccelerationStructureNV handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

The `VkAccelerationStructureCreateInfoNV` structure is defined as:

    typedef struct VkAccelerationStructureCreateInfoNV {
        VkStructureType                  sType;
        const void*                      pNext;
        VkDeviceSize                     compactedSize;
        VkAccelerationStructureInfoNV    info;
    } VkAccelerationStructureCreateInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `compactedSize` is the size from the result of vkCmdWriteAccelerationStructuresPropertiesNV if this acceleration structure is going to be the target of a compacting copy.

- `info` is the VkAccelerationStructureInfoNV structure specifying further parameters of the created acceleration structure.

Valid Usage

- If `compactedSize` is not `0` then both `info.geometryCount` and `info.instanceCount` must be `0`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_CREATE_INFO_NV`

- `pNext` must be `NULL`

- `info` must be a valid VkAccelerationStructureInfoNV structure

The `VkAccelerationStructureInfoNV` structure is defined as:

    typedef struct VkAccelerationStructureInfoNV {
        VkStructureType                        sType;
        const void*                            pNext;
        VkAccelerationStructureTypeNV          type;
        VkBuildAccelerationStructureFlagsNV    flags;
        uint32_t                               instanceCount;
        uint32_t                               geometryCount;
        const VkGeometryNV*                    pGeometries;
    } VkAccelerationStructureInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `type` is a VkAccelerationStructureTypeNV value specifying the type of acceleration structure that will be created.

- `flags` is a bitmask of VkBuildAccelerationStructureFlagBitsNV specifying additional parameters of the acceleration structure.

- `instanceCount` specifies the number of instances that will be in the new acceleration structure.

- `geometryCount` specifies the number of geometries that will be in the new acceleration structure.

- `pGeometries` is a pointer to an array of `geometryCount` VkGeometryNV structures containing the scene data being passed into the acceleration structure.

`VkAccelerationStructureInfoNV` contains information that is used both for acceleration structure creation with vkCreateAccelerationStructureNV and in combination with the actual geometric data to build the acceleration structure with vkCmdBuildAccelerationStructureNV.

Valid Usage

- `geometryCount` must be less than or equal to VkPhysicalDeviceRayTracingPropertiesNV::`maxGeometryCount`

- `instanceCount` must be less than or equal to VkPhysicalDeviceRayTracingPropertiesNV::`maxInstanceCount`

- The total number of triangles in all geometries must be less than or equal to VkPhysicalDeviceRayTracingPropertiesNV::`maxTriangleCount`

- If `type` is `VK_ACCELERATION_STRUCTURE_TYPE_TOP_LEVEL_NV` then `geometryCount` must be `0`

- If `type` is `VK_ACCELERATION_STRUCTURE_TYPE_BOTTOM_LEVEL_NV` then `instanceCount` must be `0`

- If `type` is `VK_ACCELERATION_STRUCTURE_TYPE_BOTTOM_LEVEL_NV` then the `geometryType` member of each geometry in `pGeometries` must be the same

- `flags` must be a valid combination of VkBuildAccelerationStructureFlagBitsNV values

- If `flags` has the `VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_TRACE_BIT_NV` bit set, then it must not have the `VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_BUILD_BIT_NV` bit set

- `scratch` must have been created with `VK_BUFFER_USAGE_RAY_TRACING_BIT_NV` usage flag

- If `instanceData` is not VK_NULL_HANDLE, `instanceData` must have been created with `VK_BUFFER_USAGE_RAY_TRACING_BIT_NV` usage flag

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_INFO_NV`

- `pNext` must be `NULL`

- `type` must be a valid VkAccelerationStructureTypeNV value

- `flags` must be `0`

- If `geometryCount` is not `0`, `pGeometries` must be a valid pointer to an array of `geometryCount` valid VkGeometryNV structures

To create an acceleration structure, call:

    VkResult vkCreateAccelerationStructureKHR(
        VkDevice                                    device,
        const VkAccelerationStructureCreateInfoKHR* pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkAccelerationStructureKHR*                 pAccelerationStructure);

- `device` is the logical device that creates the buffer object.

- `pCreateInfo` is a pointer to a VkAccelerationStructureCreateInfoKHR structure containing parameters affecting creation of the acceleration structure.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pAccelerationStructure` is a pointer to a `VkAccelerationStructureKHR` handle in which the resulting acceleration structure object is returned.

Similar to other objects in Vulkan, the acceleration structure creation merely creates an object with a specific “shape”. The type and quantity of geometry that can be built into an acceleration structure is determined by the parameters of VkAccelerationStructureCreateInfoKHR.

Populating the data in the object after allocating and binding memory is done with commands such as vkCmdBuildAccelerationStructureKHR, vkBuildAccelerationStructureKHR, vkCmdCopyAccelerationStructureKHR, and vkCopyAccelerationStructureKHR.

Valid Usage

- The `rayTracing` or `rayQuery` feature must be enabled

- If VkAccelerationStructureCreateInfoKHR::`deviceAddress` is not zero, the `rayTracingAccelerationStructureCaptureReplay` feature must be enabled

- If `device` was created with multiple physical devices, then the bufferDeviceAddressMultiDevice feature must be enabled

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkAccelerationStructureCreateInfoKHR structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pAccelerationStructure` must be a valid pointer to a VkAccelerationStructureKHR handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_INVALID_OPAQUE_CAPTURE_ADDRESS_KHR`

The `VkAccelerationStructureCreateInfoKHR` structure is defined as:

    typedef struct VkAccelerationStructureCreateInfoKHR {
        VkStructureType                                            sType;
        const void*                                                pNext;
        VkDeviceSize                                               compactedSize;
        VkAccelerationStructureTypeKHR                             type;
        VkBuildAccelerationStructureFlagsKHR                       flags;
        uint32_t                                                   maxGeometryCount;
        const VkAccelerationStructureCreateGeometryTypeInfoKHR*    pGeometryInfos;
        VkDeviceAddress                                            deviceAddress;
    } VkAccelerationStructureCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `compactedSize` is the size from the result of vkCmdWriteAccelerationStructuresPropertiesKHR if this acceleration structure is going to be the target of a compacting copy.

- `type` is a VkAccelerationStructureTypeKHR value specifying the type of acceleration structure that will be created.

- `flags` is a bitmask of VkBuildAccelerationStructureFlagBitsKHR specifying additional parameters of the acceleration structure.

- `maxGeometryCount` specifies the number of geometries that will be in the new acceleration structure.

- `pGeometryInfos` is an array of `maxGeometryCount` VkAccelerationStructureCreateGeometryTypeInfoKHR structures, which describe the maximum size and format of the data that will be built into the acceleration structure.

- `deviceAddress` is the device address requested for the acceleration structure if the `rayTracingAccelerationStructureCaptureReplay` feature is being used.

If `deviceAddress` is zero, no specific address is requested.

If `deviceAddress` is not zero, `deviceAddress` must be an address retrieved from an identically created acceleration structure on the same implementation. The acceleration structure must also be bound to an identically created `VkDeviceMemory` object.

Apps should avoid creating acceleration structures with app-provided addresses and implementation-provided addresses in the same process, to reduce the likelihood of `VK_ERROR_INVALID_OPAQUE_CAPTURE_ADDRESS_KHR` errors.

Valid Usage

- If `compactedSize` is not `0` then `maxGeometryCount` must be `0`

- If `type` is `VK_ACCELERATION_STRUCTURE_TYPE_BOTTOM_LEVEL_KHR` then `maxGeometryCount` must be less than or equal to VkPhysicalDeviceRayTracingPropertiesKHR::`maxGeometryCount`

- If `type` is `VK_ACCELERATION_STRUCTURE_TYPE_TOP_LEVEL_KHR` then `pGeometryInfos->pname`:maxPrimitiveCount must be less than or equal to VkPhysicalDeviceRayTracingPropertiesKHR::`maxInstanceCount`

- The total number of triangles in all geometries must be less than or equal to VkPhysicalDeviceRayTracingPropertiesKHR::`maxPrimitiveCount`

- The total number of AABBs in all geometries must be less than or equal to VkPhysicalDeviceRayTracingPropertiesKHR::`maxPrimitiveCount`

- If `type` is `VK_ACCELERATION_STRUCTURE_TYPE_TOP_LEVEL_KHR` and `compactedSize` is `0`, `maxGeometryCount` must be `1`

- If `type` is `VK_ACCELERATION_STRUCTURE_TYPE_TOP_LEVEL_KHR` and `compactedSize` is `0`, the `geometryType` member of elements of `pGeometryInfos` must be `VK_GEOMETRY_TYPE_INSTANCES_KHR`

- If `type` is `VK_ACCELERATION_STRUCTURE_TYPE_BOTTOM_LEVEL_KHR` and `compactedSize` is `0`, the `geometryType` member of elements of `pGeometryInfos` must not be `VK_GEOMETRY_TYPE_INSTANCES_KHR`

- If `type` is `VK_ACCELERATION_STRUCTURE_TYPE_BOTTOM_LEVEL_KHR` then the `geometryType` member of each geometry in `pGeometryInfos` must be the same

- If `flags` has the `VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_TRACE_BIT_KHR` bit set, then it must not have the `VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_BUILD_BIT_KHR` bit set

- If `deviceAddress` is not `0`, VkPhysicalDeviceRayTracingFeaturesKHR::`rayTracingAccelerationStructureCaptureReplay` must be `VK_TRUE`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_CREATE_INFO_KHR`

- `pNext` must be `NULL`

- `type` must be a valid VkAccelerationStructureTypeKHR value

- `flags` must be a valid combination of VkBuildAccelerationStructureFlagBitsKHR values

- `pGeometryInfos` must be a valid pointer to an array of `maxGeometryCount` valid VkAccelerationStructureCreateGeometryTypeInfoKHR structures

- `maxGeometryCount` must be greater than `0`

The `VkAccelerationStructureCreateGeometryTypeInfoKHR` structure specifies the shape of geometries that will be built into an acceleration structure and is defined as:

    typedef struct VkAccelerationStructureCreateGeometryTypeInfoKHR {
        VkStructureType      sType;
        const void*          pNext;
        VkGeometryTypeKHR    geometryType;
        uint32_t             maxPrimitiveCount;
        VkIndexType          indexType;
        uint32_t             maxVertexCount;
        VkFormat             vertexFormat;
        VkBool32             allowsTransforms;
    } VkAccelerationStructureCreateGeometryTypeInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `geometryType` is a VkGeometryTypeKHR that describes the type of an acceleration structure geometry.

- `maxPrimitiveCount` describes the maximum number of primitives that can be built into an acceleration structure geometry.

- `indexType` is a VkIndexType that describes the index type used to build this geometry when `geometryType` is `VK_GEOMETRY_TYPE_TRIANGLES_KHR`.

- `maxVertexCount` describes the maximum vertex count that can be used to build an acceleration structure geometry when `geometryType` is `VK_GEOMETRY_TYPE_TRIANGLES_KHR`.

- `vertexFormat` is a VkFormat that describes the vertex format used to build this geometry when `geometryType` is `VK_GEOMETRY_TYPE_TRIANGLES_KHR`.

- `allowsTransforms` indicates whether transform data can be used by this acceleration structure or not, when `geometryType` is `VK_GEOMETRY_TYPE_TRIANGLES_KHR`.

When `geometryType` is `VK_GEOMETRY_TYPE_TRIANGLES_KHR`:

- if `indexType` is `VK_INDEX_TYPE_NONE_KHR`, then this structure describes a set of triangles.

- if `indexType` is not `VK_INDEX_TYPE_NONE_KHR`, then this structure describes a set of indexed triangles.

Valid Usage

- If `geometryType` is `VK_GEOMETRY_TYPE_TRIANGLES_KHR`, `vertexFormat` must support the `VK_FORMAT_FEATURE_ACCELERATION_STRUCTURE_VERTEX_BUFFER_BIT_KHR` in VkFormatProperties::`bufferFeatures` as returned by vkGetPhysicalDeviceFormatProperties2

- If `geometryType` is `VK_GEOMETRY_TYPE_TRIANGLES_KHR`, `indexType` must be `VK_INDEX_TYPE_UINT16`, `VK_INDEX_TYPE_UINT32`, or `VK_INDEX_TYPE_NONE_KHR`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_CREATE_GEOMETRY_TYPE_INFO_KHR`

- `pNext` must be `NULL`

- `geometryType` must be a valid VkGeometryTypeKHR value

- `indexType` must be a valid VkIndexType value

- If `vertexFormat` is not `0`, `vertexFormat` must be a valid VkFormat value

Values which can be set in VkAccelerationStructureCreateInfoKHR::`type` or VkAccelerationStructureInfoNV::`type` specifying the type of acceleration structure, are:

    typedef enum VkAccelerationStructureTypeKHR {
        VK_ACCELERATION_STRUCTURE_TYPE_TOP_LEVEL_KHR = 0,
        VK_ACCELERATION_STRUCTURE_TYPE_BOTTOM_LEVEL_KHR = 1,
        VK_ACCELERATION_STRUCTURE_TYPE_TOP_LEVEL_NV = VK_ACCELERATION_STRUCTURE_TYPE_TOP_LEVEL_KHR,
        VK_ACCELERATION_STRUCTURE_TYPE_BOTTOM_LEVEL_NV = VK_ACCELERATION_STRUCTURE_TYPE_BOTTOM_LEVEL_KHR,
        VK_ACCELERATION_STRUCTURE_TYPE_MAX_ENUM_KHR = 0x7FFFFFFF
    } VkAccelerationStructureTypeKHR;

or the equivalent

    typedef VkAccelerationStructureTypeKHR VkAccelerationStructureTypeNV;

- `VK_ACCELERATION_STRUCTURE_TYPE_TOP_LEVEL_KHR` is a top-level acceleration structure containing instance data referring to bottom-level level acceleration structures.

- `VK_ACCELERATION_STRUCTURE_TYPE_BOTTOM_LEVEL_KHR` is a bottom-level acceleration structure containing the AABBs or geometry to be intersected.

Bits which can be set in VkAccelerationStructureCreateInfoKHR::`flags` or VkAccelerationStructureInfoNV::`flags` specifying additional parameters for acceleration structure builds, are:

    typedef enum VkBuildAccelerationStructureFlagBitsKHR {
        VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_UPDATE_BIT_KHR = 0x00000001,
        VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_COMPACTION_BIT_KHR = 0x00000002,
        VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_TRACE_BIT_KHR = 0x00000004,
        VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_BUILD_BIT_KHR = 0x00000008,
        VK_BUILD_ACCELERATION_STRUCTURE_LOW_MEMORY_BIT_KHR = 0x00000010,
        VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_UPDATE_BIT_NV = VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_UPDATE_BIT_KHR,
        VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_COMPACTION_BIT_NV = VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_COMPACTION_BIT_KHR,
        VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_TRACE_BIT_NV = VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_TRACE_BIT_KHR,
        VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_BUILD_BIT_NV = VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_BUILD_BIT_KHR,
        VK_BUILD_ACCELERATION_STRUCTURE_LOW_MEMORY_BIT_NV = VK_BUILD_ACCELERATION_STRUCTURE_LOW_MEMORY_BIT_KHR,
        VK_BUILD_ACCELERATION_STRUCTURE_FLAG_BITS_MAX_ENUM_KHR = 0x7FFFFFFF
    } VkBuildAccelerationStructureFlagBitsKHR;

or the equivalent

    typedef VkBuildAccelerationStructureFlagBitsKHR VkBuildAccelerationStructureFlagBitsNV;

- `VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_UPDATE_BIT_KHR` indicates that the specified acceleration structure can be updated with `update` of `VK_TRUE` in vkCmdBuildAccelerationStructureKHR or vkCmdBuildAccelerationStructureNV .

- `VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_COMPACTION_BIT_KHR` indicates that the specified acceleration structure can act as the source for a copy acceleration structure command with `mode` of `VK_COPY_ACCELERATION_STRUCTURE_MODE_COMPACT_KHR` to produce a compacted acceleration structure.

- `VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_TRACE_BIT_KHR` indicates that the given acceleration structure build should prioritize trace performance over build time.

- `VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_BUILD_BIT_KHR` indicates that the given acceleration structure build should prioritize build time over trace performance.

- `VK_BUILD_ACCELERATION_STRUCTURE_LOW_MEMORY_BIT_KHR` indicates that this acceleration structure should minimize the size of the scratch memory and the final result build, potentially at the expense of build time or trace performance.

| Note `VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_UPDATE_BIT_KHR` and `VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_COMPACTION_BIT_KHR` may take more time and memory than a normal build, and so should only be used when those features are needed.

    typedef VkFlags VkBuildAccelerationStructureFlagsKHR;

or the equivalent

    typedef VkBuildAccelerationStructureFlagsKHR VkBuildAccelerationStructureFlagsNV;

`VkBuildAccelerationStructureFlagsKHR` is a bitmask type for setting a mask of zero or more VkBuildAccelerationStructureFlagBitsKHR.

The `VkGeometryNV` structure describes geometry in a bottom-level acceleration structure and is defined as:

    typedef struct VkGeometryNV {
        VkStructureType       sType;
        const void*           pNext;
        VkGeometryTypeKHR     geometryType;
        VkGeometryDataNV      geometry;
        VkGeometryFlagsKHR    flags;
    } VkGeometryNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `geometryType` specifies the VkGeometryTypeKHR which this geometry refers to.

- `geometry` contains the geometry data as described in VkGeometryDataNV.

- `flags` has VkGeometryFlagBitsKHR describing options for this geometry.

Valid Usage

- `geometryType` must be `VK_GEOMETRY_TYPE_TRIANGLES_NV` or `VK_GEOMETRY_TYPE_AABBS_NV`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_GEOMETRY_NV`

- `pNext` must be `NULL`

- `geometryType` must be a valid VkGeometryTypeKHR value

- `geometry` must be a valid VkGeometryDataNV structure

- `flags` must be a valid combination of VkGeometryFlagBitsKHR values

Geometry types are specified by VkGeometryTypeKHR, which takes values:

    typedef enum VkGeometryTypeKHR {
        VK_GEOMETRY_TYPE_TRIANGLES_KHR = 0,
        VK_GEOMETRY_TYPE_AABBS_KHR = 1,
        VK_GEOMETRY_TYPE_INSTANCES_KHR = 1000150000,
        VK_GEOMETRY_TYPE_TRIANGLES_NV = VK_GEOMETRY_TYPE_TRIANGLES_KHR,
        VK_GEOMETRY_TYPE_AABBS_NV = VK_GEOMETRY_TYPE_AABBS_KHR,
        VK_GEOMETRY_TYPE_MAX_ENUM_KHR = 0x7FFFFFFF
    } VkGeometryTypeKHR;

or the equivalent

    typedef VkGeometryTypeKHR VkGeometryTypeNV;

- `VK_GEOMETRY_TYPE_TRIANGLES_KHR` specifies a geometry type consisting of triangles.

- `VK_GEOMETRY_TYPE_AABBS_KHR` specifies a geometry type consisting of axis-aligned bounding boxes.

- `VK_GEOMETRY_TYPE_INSTANCES_KHR` specifies a geometry type consisting of acceleration structure instances.

Bits specifying additional parameters for geometries in acceleration structure builds, are:

    typedef enum VkGeometryFlagBitsKHR {
        VK_GEOMETRY_OPAQUE_BIT_KHR = 0x00000001,
        VK_GEOMETRY_NO_DUPLICATE_ANY_HIT_INVOCATION_BIT_KHR = 0x00000002,
        VK_GEOMETRY_OPAQUE_BIT_NV = VK_GEOMETRY_OPAQUE_BIT_KHR,
        VK_GEOMETRY_NO_DUPLICATE_ANY_HIT_INVOCATION_BIT_NV = VK_GEOMETRY_NO_DUPLICATE_ANY_HIT_INVOCATION_BIT_KHR,
        VK_GEOMETRY_FLAG_BITS_MAX_ENUM_KHR = 0x7FFFFFFF
    } VkGeometryFlagBitsKHR;

or the equivalent

    typedef VkGeometryFlagBitsKHR VkGeometryFlagBitsNV;

- `VK_GEOMETRY_OPAQUE_BIT_KHR` indicates that this geometry does not invoke the any-hit shaders even if present in a hit group.

- `VK_GEOMETRY_NO_DUPLICATE_ANY_HIT_INVOCATION_BIT_KHR` indicates that the implementation must only call the any-hit shader a single time for each primitive in this geometry. If this bit is absent an implementation may invoke the any-hit shader more than once for this geometry.

    typedef VkFlags VkGeometryFlagsKHR;

or the equivalent

    typedef VkGeometryFlagsKHR VkGeometryFlagsNV;

`VkGeometryFlagsKHR` is a bitmask type for setting a mask of zero or more VkGeometryFlagBitsKHR.

The `VkGeometryDataNV` structure specifes geometry in a bottom-level acceleration structure and is defined as:

    typedef struct VkGeometryDataNV {
        VkGeometryTrianglesNV    triangles;
        VkGeometryAABBNV         aabbs;
    } VkGeometryDataNV;

- `triangles` contains triangle data if VkGeometryNV::`geometryType` is `VK_GEOMETRY_TYPE_TRIANGLES_NV`.

- `aabbs` contains axis-aligned bounding box data if VkGeometryNV::`geometryType` is `VK_GEOMETRY_TYPE_AABBS_NV`.

Valid Usage (Implicit)

- `triangles` must be a valid VkGeometryTrianglesNV structure

- `aabbs` must be a valid VkGeometryAABBNV structure

The `VkGeometryTrianglesNV` structure specifies triangle geometry in a bottom-level acceleration structure and is defined as:

    typedef struct VkGeometryTrianglesNV {
        VkStructureType    sType;
        const void*        pNext;
        VkBuffer           vertexData;
        VkDeviceSize       vertexOffset;
        uint32_t           vertexCount;
        VkDeviceSize       vertexStride;
        VkFormat           vertexFormat;
        VkBuffer           indexData;
        VkDeviceSize       indexOffset;
        uint32_t           indexCount;
        VkIndexType        indexType;
        VkBuffer           transformData;
        VkDeviceSize       transformOffset;
    } VkGeometryTrianglesNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `vertexData` is the buffer containing vertex data for this geometry.

- `vertexOffset` is the offset in bytes within `vertexData` containing vertex data for this geometry.

- `vertexCount` is the number of valid vertices.

- `vertexStride` is the stride in bytes between each vertex.

- `vertexFormat` is a VkFormat describing the format of each vertex element.

- `indexData` is the buffer containing index data for this geometry.

- `indexOffset` is the offset in bytes within `indexData` containing index data for this geometry.

- `indexCount` is the number of indices to include in this geometry.

- `indexType` is a VkIndexType describing the format of each index.

- `transformData` is an optional buffer containing an VkTransformMatrixNV structure defining a transformation to be applied to this geometry.

- `transformOffset` is the offset in bytes in `transformData` of the transform information described above.

If `indexType` is `VK_INDEX_TYPE_NONE_NV`, then this structure describes a set of triangles determined by `vertexCount`. Otherwise, this structure describes a set of indexed triangles determined by `indexCount`.

Valid Usage

- `vertexOffset` must be less than the size of `vertexData`

- `vertexOffset` must be a multiple of the component size of `vertexFormat`

- `vertexFormat` must be one of `VK_FORMAT_R32G32B32_SFLOAT`, `VK_FORMAT_R32G32_SFLOAT`, `VK_FORMAT_R16G16B16_SFLOAT`, `VK_FORMAT_R16G16_SFLOAT`, `VK_FORMAT_R16G16_SNORM`, or `VK_FORMAT_R16G16B16_SNORM`

- `indexOffset` must be less than the size of `indexData`

- `indexOffset` must be a multiple of the element size of `indexType`

- `indexType` must be `VK_INDEX_TYPE_UINT16`, `VK_INDEX_TYPE_UINT32`, or `VK_INDEX_TYPE_NONE_NV`

- `indexData` must be VK_NULL_HANDLE if `indexType` is `VK_INDEX_TYPE_NONE_NV`

- `indexData` must be a valid `VkBuffer` handle if `indexType` is not `VK_INDEX_TYPE_NONE_NV`

- `indexCount` must be `0` if `indexType` is `VK_INDEX_TYPE_NONE_NV`

- `transformOffset` must be less than the size of `transformData`

- `transformOffset` must be a multiple of `16`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_GEOMETRY_TRIANGLES_NV`

- `pNext` must be `NULL`

- If `vertexData` is not VK_NULL_HANDLE, `vertexData` must be a valid VkBuffer handle

- `vertexFormat` must be a valid VkFormat value

- If `indexData` is not VK_NULL_HANDLE, `indexData` must be a valid VkBuffer handle

- `indexType` must be a valid VkIndexType value

- If `transformData` is not VK_NULL_HANDLE, `transformData` must be a valid VkBuffer handle

- Each of `indexData`, `transformData`, and `vertexData` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

The `VkGeometryAABBNV` structure specifies axis-aligned bounding box geometry in a bottom-level acceleration structure, and is defined as:

    typedef struct VkGeometryAABBNV {
        VkStructureType    sType;
        const void*        pNext;
        VkBuffer           aabbData;
        uint32_t           numAABBs;
        uint32_t           stride;
        VkDeviceSize       offset;
    } VkGeometryAABBNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `aabbData` is the buffer containing axis-aligned bounding box data.

- `numAABBs` is the number of AABBs in this geometry.

- `stride` is the stride in bytes between AABBs in `aabbData`.

- `offset` is the offset in bytes of the first AABB in `aabbData`.

The AABB data in memory is six 32-bit floats consisting of the minimum x, y, and z values followed by the maximum x, y, and z values.

Valid Usage

- `offset` must be less than the size of `aabbData`

- `offset` must be a multiple of `8`

- `stride` must be a multiple of `8`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_GEOMETRY_AABB_NV`

- `pNext` must be `NULL`

- If `aabbData` is not VK_NULL_HANDLE, `aabbData` must be a valid VkBuffer handle

To destroy an acceleration structure, call:

    void vkDestroyAccelerationStructureKHR(
        VkDevice                                    device,
        VkAccelerationStructureKHR                  accelerationStructure,
        const VkAllocationCallbacks*                pAllocator);

or the equivalent command

    void vkDestroyAccelerationStructureNV(
        VkDevice                                    device,
        VkAccelerationStructureKHR                  accelerationStructure,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that destroys the buffer.

- `accelerationStructure` is the acceleration structure to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage

- All submitted commands that refer to `accelerationStructure` must have completed execution

- If `VkAllocationCallbacks` were provided when `accelerationStructure` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `accelerationStructure` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `accelerationStructure` must be a valid VkAccelerationStructureKHR handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `accelerationStructure` must have been created, allocated, or retrieved from `device`

An acceleration structure has memory requirements for the structure object itself, scratch space for the build, and scratch space for the update.

Scratch space is allocated as a `VkBuffer`, so for `VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_BUILD_SCRATCH_NV` and `VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_UPDATE_SCRATCH_NV` the `pMemoryRequirements->alignment` and `pMemoryRequirements->memoryTypeBits` values returned by this call must be filled with zero, and should be ignored by the application.

To query the memory requirements call:

    void vkGetAccelerationStructureMemoryRequirementsNV(
        VkDevice                                    device,
        const VkAccelerationStructureMemoryRequirementsInfoNV* pInfo,
        VkMemoryRequirements2KHR*                   pMemoryRequirements);

- `device` is the logical device on which the acceleration structure was created.

- `pInfo` specifies the acceleration structure to get memory requirements for.

- `pMemoryRequirements` returns the requested acceleration structure memory requirements.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pInfo` must be a valid pointer to a valid VkAccelerationStructureMemoryRequirementsInfoNV structure

- `pMemoryRequirements` must be a valid pointer to a VkMemoryRequirements2KHR structure

The `VkAccelerationStructureMemoryRequirementsInfoNV` structure is defined as:

    typedef struct VkAccelerationStructureMemoryRequirementsInfoNV {
        VkStructureType                                    sType;
        const void*                                        pNext;
        VkAccelerationStructureMemoryRequirementsTypeNV    type;
        VkAccelerationStructureNV                          accelerationStructure;
    } VkAccelerationStructureMemoryRequirementsInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `type` selects the type of memory requirement being queried. `VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_OBJECT_NV` returns the memory requirements for the object itself. `VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_BUILD_SCRATCH_NV` returns the memory requirements for the scratch memory when doing a build. `VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_UPDATE_SCRATCH_NV` returns the memory requirements for the scratch memory when doing an update.

- `accelerationStructure` is the acceleration structure to be queried for memory requirements.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_INFO_NV`

- `pNext` must be `NULL`

- `type` must be a valid VkAccelerationStructureMemoryRequirementsTypeNV value

- `accelerationStructure` must be a valid VkAccelerationStructureNV handle

An acceleration structure has memory requirements for the structure object itself, scratch space for the build, and scratch space for the update.

Scratch space is allocated as a `VkBuffer`, so for `VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_BUILD_SCRATCH_KHR` and `VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_UPDATE_SCRATCH_KHR` the `pMemoryRequirements->alignment` and `pMemoryRequirements->memoryTypeBits` values returned by this call must be filled with zero, and should be ignored by the application.

To query the memory requirements call:

    void vkGetAccelerationStructureMemoryRequirementsKHR(
        VkDevice                                    device,
        const VkAccelerationStructureMemoryRequirementsInfoKHR* pInfo,
        VkMemoryRequirements2*                      pMemoryRequirements);

- `device` is the logical device on which the acceleration structure was created.

- `pInfo` specifies the acceleration structure to get memory requirements for.

- `pMemoryRequirements` returns the requested acceleration structure memory requirements.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pInfo` must be a valid pointer to a valid VkAccelerationStructureMemoryRequirementsInfoKHR structure

- `pMemoryRequirements` must be a valid pointer to a VkMemoryRequirements2 structure

The `VkAccelerationStructureMemoryRequirementsInfoKHR` structure is defined as:

    typedef struct VkAccelerationStructureMemoryRequirementsInfoKHR {
        VkStructureType                                     sType;
        const void*                                         pNext;
        VkAccelerationStructureMemoryRequirementsTypeKHR    type;
        VkAccelerationStructureBuildTypeKHR                 buildType;
        VkAccelerationStructureKHR                          accelerationStructure;
    } VkAccelerationStructureMemoryRequirementsInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `buildType` selects the build types whose memory requirements are being queried.

- `type` selects the type of memory requirement being queried. `VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_OBJECT_KHR` returns the memory requirements for the object itself. `VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_BUILD_SCRATCH_KHR` returns the memory requirements for the scratch memory when doing a build. `VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_UPDATE_SCRATCH_KHR` returns the memory requirements for the scratch memory when doing an update.

- `accelerationStructure` is the acceleration structure to be queried for memory requirements.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_INFO_KHR`

- `pNext` must be `NULL`

- `type` must be a valid VkAccelerationStructureMemoryRequirementsTypeKHR value

- `buildType` must be a valid VkAccelerationStructureBuildTypeKHR value

- `accelerationStructure` must be a valid VkAccelerationStructureKHR handle

Possible values of `type` in `VkAccelerationStructureMemoryRequirementsInfoKHR` are:,

    typedef enum VkAccelerationStructureMemoryRequirementsTypeKHR {
        VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_OBJECT_KHR = 0,
        VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_BUILD_SCRATCH_KHR = 1,
        VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_UPDATE_SCRATCH_KHR = 2,
        VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_OBJECT_NV = VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_OBJECT_KHR,
        VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_BUILD_SCRATCH_NV = VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_BUILD_SCRATCH_KHR,
        VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_UPDATE_SCRATCH_NV = VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_UPDATE_SCRATCH_KHR,
        VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_MAX_ENUM_KHR = 0x7FFFFFFF
    } VkAccelerationStructureMemoryRequirementsTypeKHR;

or the equivalent

    typedef VkAccelerationStructureMemoryRequirementsTypeKHR VkAccelerationStructureMemoryRequirementsTypeNV;

- `VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_OBJECT_KHR` requests the memory requirement for the `VkAccelerationStructureKHR` backing store.

- `VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_BUILD_SCRATCH_KHR` requests the memory requirement for scratch space during the initial build.

- `VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_UPDATE_SCRATCH_KHR` requests the memory requirement for scratch space during an update.

Possible values of `buildType` in `VkAccelerationStructureMemoryRequirementsInfoKHR` are:

    typedef enum VkAccelerationStructureBuildTypeKHR {
        VK_ACCELERATION_STRUCTURE_BUILD_TYPE_HOST_KHR = 0,
        VK_ACCELERATION_STRUCTURE_BUILD_TYPE_DEVICE_KHR = 1,
        VK_ACCELERATION_STRUCTURE_BUILD_TYPE_HOST_OR_DEVICE_KHR = 2,
        VK_ACCELERATION_STRUCTURE_BUILD_TYPE_MAX_ENUM_KHR = 0x7FFFFFFF
    } VkAccelerationStructureBuildTypeKHR;

- `VK_ACCELERATION_STRUCTURE_BUILD_TYPE_HOST_KHR` requests the memory requirement for operations performed by the host.

- `VK_ACCELERATION_STRUCTURE_BUILD_TYPE_DEVICE_KHR` requests the memory requirement for operations performed by the device.

- `VK_ACCELERATION_STRUCTURE_BUILD_TYPE_HOST_OR_DEVICE_KHR` requests the memory requirement for operations performed by either the host, or the device.

To attach memory to one or more acceleration structures at a time, call:

    VkResult vkBindAccelerationStructureMemoryKHR(
        VkDevice                                    device,
        uint32_t                                    bindInfoCount,
        const VkBindAccelerationStructureMemoryInfoKHR* pBindInfos);

or the equivalent command

    VkResult vkBindAccelerationStructureMemoryNV(
        VkDevice                                    device,
        uint32_t                                    bindInfoCount,
        const VkBindAccelerationStructureMemoryInfoKHR* pBindInfos);

- `device` is the logical device that owns the acceleration structures and memory.

- `bindInfoCount` is the number of elements in `pBindInfos`.

- `pBindInfos` is a pointer to an array of VkBindAccelerationStructureMemoryInfoKHR structures describing acceleration structures and memory to bind.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pBindInfos` must be a valid pointer to an array of `bindInfoCount` valid VkBindAccelerationStructureMemoryInfoKHR structures

- `bindInfoCount` must be greater than `0`

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkBindAccelerationStructureMemoryInfoKHR` structure is defined as:

    typedef struct VkBindAccelerationStructureMemoryInfoKHR {
        VkStructureType               sType;
        const void*                   pNext;
        VkAccelerationStructureKHR    accelerationStructure;
        VkDeviceMemory                memory;
        VkDeviceSize                  memoryOffset;
        uint32_t                      deviceIndexCount;
        const uint32_t*               pDeviceIndices;
    } VkBindAccelerationStructureMemoryInfoKHR;

or the equivalent

    typedef VkBindAccelerationStructureMemoryInfoKHR VkBindAccelerationStructureMemoryInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `accelerationStructure` is the acceleration structure to be attached to memory.

- `memory` is a `VkDeviceMemory` object describing the device memory to attach.

- `memoryOffset` is the start offset of the region of memory that is to be bound to the acceleration structure. The number of bytes returned in the VkMemoryRequirements::`size` member in `memory`, starting from `memoryOffset` bytes, will be bound to the specified acceleration structure.

- `deviceIndexCount` is the number of elements in `pDeviceIndices`.

- `pDeviceIndices` is a pointer to an array of device indices.

Valid Usage

- `accelerationStructure` must not already be backed by a memory object

- `memoryOffset` must be less than the size of `memory`

- `memory` must have been allocated using one of the memory types allowed in the `memoryTypeBits` member of the VkMemoryRequirements structure returned from a call to vkGetAccelerationStructureMemoryRequirementsKHR with `accelerationStructure` and `type` of `VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_OBJECT_KHR`

- `memoryOffset` must be an integer multiple of the `alignment` member of the VkMemoryRequirements structure returned from a call to vkGetAccelerationStructureMemoryRequirementsKHR with `accelerationStructure` and `type` of `VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_OBJECT_KHR`

- The `size` member of the `VkMemoryRequirements` structure returned from a call to vkGetAccelerationStructureMemoryRequirementsKHR with `accelerationStructure` and `type` of `VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_OBJECT_KHR` must be less than or equal to the size of `memory` minus `memoryOffset`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_BIND_ACCELERATION_STRUCTURE_MEMORY_INFO_KHR`

- `pNext` must be `NULL`

- `accelerationStructure` must be a valid VkAccelerationStructureKHR handle

- `memory` must be a valid VkDeviceMemory handle

- If `deviceIndexCount` is not `0`, `pDeviceIndices` must be a valid pointer to an array of `deviceIndexCount` `uint32_t` values

- Both of `accelerationStructure`, and `memory` must have been created, allocated, or retrieved from the same VkDevice

To allow constructing geometry instances with device code if desired, we need to be able to query a opaque handle for an acceleration structure. This handle is a value of 8 bytes. To get this handle, call:

    VkResult vkGetAccelerationStructureHandleNV(
        VkDevice                                    device,
        VkAccelerationStructureKHR                  accelerationStructure,
        size_t                                      dataSize,
        void*                                       pData);

- `device` is the logical device that owns the acceleration structures.

- `accelerationStructure` is the acceleration structure.

- `dataSize` is the size in bytes of the buffer pointed to by `pData`.

- `pData` is a pointer to a user-allocated buffer where the results will be written.

Valid Usage

- `dataSize` must be large enough to contain the result of the query, as described above

- `accelerationStructure` must be bound completely and contiguously to a single `VkDeviceMemory` object via vkBindAccelerationStructureMemoryKHR

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `accelerationStructure` must be a valid VkAccelerationStructureKHR handle

- `pData` must be a valid pointer to an array of `dataSize` bytes

- `dataSize` must be greater than `0`

- `accelerationStructure` must have been created, allocated, or retrieved from `device`

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

To query the 64-bit device address for an acceleration structure, call:

    VkDeviceAddress vkGetAccelerationStructureDeviceAddressKHR(
        VkDevice                                    device,
        const VkAccelerationStructureDeviceAddressInfoKHR* pInfo);

- `device` is the logical device that the accelerationStructure was created on.

- `pInfo` is a pointer to a VkAccelerationStructureDeviceAddressInfoKHR structure specifying the acceleration structure to retrieve an address for.

The 64-bit return value is an address of the acceleration structure, which can be used for device and shader operations that involve acceleration structures, such as ray traversal and acceleration structure building.

If the acceleration structure was created with a non-zero value of VkAccelerationStructureCreateInfoKHR::`deviceAddress` the return value will be the same address.

Valid Usage

- If `device` was created with multiple physical devices, then the bufferDeviceAddressMultiDevice feature must be enabled

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pInfo` must be a valid pointer to a valid VkAccelerationStructureDeviceAddressInfoKHR structure

The `VkAccelerationStructureDeviceAddressInfoKHR` structure is defined as:

    typedef struct VkAccelerationStructureDeviceAddressInfoKHR {
        VkStructureType               sType;
        const void*                   pNext;
        VkAccelerationStructureKHR    accelerationStructure;
    } VkAccelerationStructureDeviceAddressInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `accelerationStructure` specifies the acceleration structure whose address is being queried.

Valid Usage
Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_DEVICE_ADDRESS_INFO_KHR`

- `pNext` must be `NULL`

- `accelerationStructure` must be a valid VkAccelerationStructureKHR handle

## 12. Samplers

`VkSampler` objects represent the state of an image sampler which is used by the implementation to read image data and apply filtering and other transformations for the shader.

Samplers are represented by `VkSampler` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkSampler)

To create a sampler object, call:

    VkResult vkCreateSampler(
        VkDevice                                    device,
        const VkSamplerCreateInfo*                  pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkSampler*                                  pSampler);

- `device` is the logical device that creates the sampler.

- `pCreateInfo` is a pointer to a VkSamplerCreateInfo structure specifying the state of the sampler object.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pSampler` is a pointer to a VkSampler handle in which the resulting sampler object is returned.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkSamplerCreateInfo structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pSampler` must be a valid pointer to a VkSampler handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_TOO_MANY_OBJECTS`

The `VkSamplerCreateInfo` structure is defined as:

    typedef struct VkSamplerCreateInfo {
        VkStructureType         sType;
        const void*             pNext;
        VkSamplerCreateFlags    flags;
        VkFilter                magFilter;
        VkFilter                minFilter;
        VkSamplerMipmapMode     mipmapMode;
        VkSamplerAddressMode    addressModeU;
        VkSamplerAddressMode    addressModeV;
        VkSamplerAddressMode    addressModeW;
        float                   mipLodBias;
        VkBool32                anisotropyEnable;
        float                   maxAnisotropy;
        VkBool32                compareEnable;
        VkCompareOp             compareOp;
        float                   minLod;
        float                   maxLod;
        VkBorderColor           borderColor;
        VkBool32                unnormalizedCoordinates;
    } VkSamplerCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkSamplerCreateFlagBits describing additional parameters of the sampler.

- `magFilter` is a VkFilter value specifying the magnification filter to apply to lookups.

- `minFilter` is a VkFilter value specifying the minification filter to apply to lookups.

- `mipmapMode` is a VkSamplerMipmapMode value specifying the mipmap filter to apply to lookups.

- `addressModeU` is a VkSamplerAddressMode value specifying the addressing mode for outside [0..1] range for U coordinate.

- `addressModeV` is a VkSamplerAddressMode value specifying the addressing mode for outside [0..1] range for V coordinate.

- `addressModeW` is a VkSamplerAddressMode value specifying the addressing mode for outside [0..1] range for W coordinate.

- `mipLodBias` is the bias to be added to mipmap LOD (level-of-detail) calculation and bias provided by image sampling functions in SPIR-V, as described in the Level-of-Detail Operation section.

- `anisotropyEnable` is `VK_TRUE` to enable anisotropic filtering, as described in the Texel Anisotropic Filtering section, or `VK_FALSE` otherwise.

- `maxAnisotropy` is the anisotropy value clamp used by the sampler when `anisotropyEnable` is `VK_TRUE`. If `anisotropyEnable` is `VK_FALSE`, `maxAnisotropy` is ignored.

- `compareEnable` is `VK_TRUE` to enable comparison against a reference value during lookups, or `VK_FALSE` otherwise.

  - Note: Some implementations will default to shader state if this member does not match.

- `compareOp` is a VkCompareOp value specifying the comparison function to apply to fetched data before filtering as described in the Depth Compare Operation section.

- `minLod` and `maxLod` are the values used to clamp the computed LOD value, as described in the Level-of-Detail Operation section.

- `borderColor` is a VkBorderColor value specifying the predefined border color to use.

- `unnormalizedCoordinates` controls whether to use unnormalized or normalized texel coordinates to address texels of the image. When set to `VK_TRUE`, the range of the image coordinates used to lookup the texel is in the range of zero to the image dimensions for x, y and z. When set to `VK_FALSE` the range of image coordinates is zero to one.

  When `unnormalizedCoordinates` is `VK_TRUE`, images the sampler is used with in the shader have the following requirements:

  - The `viewType` must be either `VK_IMAGE_VIEW_TYPE_1D` or `VK_IMAGE_VIEW_TYPE_2D`.

  - The image view must have a single layer and a single mip level.

  When `unnormalizedCoordinates` is `VK_TRUE`, image built-in functions in the shader that use the sampler have the following requirements:

  - The functions must not use projection.

  - The functions must not use offsets.

| Mapping of OpenGL to Vulkan filter modes `magFilter` values of `VK_FILTER_NEAREST` and `VK_FILTER_LINEAR` directly correspond to `GL_NEAREST` and `GL_LINEAR` magnification filters. `minFilter` and `mipmapMode` combine to correspond to the similarly named OpenGL minification filter of `GL_minFilter_MIPMAP_mipmapMode` (e.g. `minFilter` of `VK_FILTER_LINEAR` and `mipmapMode` of `VK_SAMPLER_MIPMAP_MODE_NEAREST` correspond to `GL_LINEAR_MIPMAP_NEAREST`). There are no Vulkan filter modes that directly correspond to OpenGL minification filters of `GL_LINEAR` or `GL_NEAREST`, but they can be emulated using `VK_SAMPLER_MIPMAP_MODE_NEAREST`, `minLod` = 0, and `maxLod` = 0.25, and using `minFilter` = `VK_FILTER_LINEAR` or `minFilter` = `VK_FILTER_NEAREST`, respectively. Note that using a `maxLod` of zero would cause magnification to always be performed, and the `magFilter` to always be used. This is valid, just not an exact match for OpenGL behavior. Clamping the maximum LOD to 0.25 allows the λ value to be non-zero and minification to be performed, while still always rounding down to the base level. If the `minFilter` and `magFilter` are equal, then using a `maxLod` of zero also works.

The maximum number of sampler objects which can be simultaneously created on a device is implementation-dependent and specified by the maxSamplerAllocationCount member of the VkPhysicalDeviceLimits structure. If `maxSamplerAllocationCount` is exceeded, `vkCreateSampler` will return `VK_ERROR_TOO_MANY_OBJECTS`.

Since VkSampler is a non-dispatchable handle type, implementations may return the same handle for sampler state vectors that are identical. In such cases, all such objects would only count once against the `maxSamplerAllocationCount` limit.

Valid Usage

- The absolute value of `mipLodBias` must be less than or equal to `VkPhysicalDeviceLimits`::`maxSamplerLodBias`

- `maxLod` must be greater than or equal to `minLod`

- If the anisotropic sampling feature is not enabled, `anisotropyEnable` must be `VK_FALSE`

- If `anisotropyEnable` is `VK_TRUE`, `maxAnisotropy` must be between `1.0` and `VkPhysicalDeviceLimits`::`maxSamplerAnisotropy`, inclusive

- If sampler Y′CBCR conversion is enabled and `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_SEPARATE_RECONSTRUCTION_FILTER_BIT` is not set for the format, `minFilter` and `magFilter` must be equal to the sampler Y′CBCR conversion’s `chromaFilter`

- If `unnormalizedCoordinates` is `VK_TRUE`, `minFilter` and `magFilter` must be equal

- If `unnormalizedCoordinates` is `VK_TRUE`, `mipmapMode` must be `VK_SAMPLER_MIPMAP_MODE_NEAREST`

- If `unnormalizedCoordinates` is `VK_TRUE`, `minLod` and `maxLod` must be zero

- If `unnormalizedCoordinates` is `VK_TRUE`, `addressModeU` and `addressModeV` must each be either `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE` or `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER`

- If `unnormalizedCoordinates` is `VK_TRUE`, `anisotropyEnable` must be `VK_FALSE`

- If `unnormalizedCoordinates` is `VK_TRUE`, `compareEnable` must be `VK_FALSE`

- If any of `addressModeU`, `addressModeV` or `addressModeW` are `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER`, `borderColor` must be a valid VkBorderColor value

- If sampler Y′CBCR conversion is enabled, `addressModeU`, `addressModeV`, and `addressModeW` must be `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`, `anisotropyEnable` must be `VK_FALSE`, and `unnormalizedCoordinates` must be `VK_FALSE`

- The sampler reduction mode must be set to `VK_SAMPLER_REDUCTION_MODE_WEIGHTED_AVERAGE` if sampler Y′CBCR conversion is enabled

- If samplerMirrorClampToEdge is not enabled, and if the `VK_KHR_sampler_mirror_clamp_to_edge` extension is not enabled, `addressModeU`, `addressModeV` and `addressModeW` must not be `VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE`

- If `compareEnable` is `VK_TRUE`, `compareOp` must be a valid VkCompareOp value

- If either `magFilter` or `minFilter` is `VK_FILTER_CUBIC_EXT`, `anisotropyEnable` must be `VK_FALSE`

- If `compareEnable` is `VK_TRUE`, the `reductionMode` member of VkSamplerReductionModeCreateInfo must be `VK_SAMPLER_REDUCTION_MODE_WEIGHTED_AVERAGE`

- If `flags` includes `VK_SAMPLER_CREATE_SUBSAMPLED_BIT_EXT`, then `minFilter` and `magFilter` must be equal.

- If `flags` includes `VK_SAMPLER_CREATE_SUBSAMPLED_BIT_EXT`, then `mipmapMode` must be `VK_SAMPLER_MIPMAP_MODE_NEAREST`.

- If `flags` includes `VK_SAMPLER_CREATE_SUBSAMPLED_BIT_EXT`, then `minLod` and `maxLod` must be zero.

- If `flags` includes `VK_SAMPLER_CREATE_SUBSAMPLED_BIT_EXT`, then `addressModeU` and `addressModeV` must each be either `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE` or `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER`.

- If `flags` includes `VK_SAMPLER_CREATE_SUBSAMPLED_BIT_EXT`, then `anisotropyEnable` must be `VK_FALSE`.

- If `flags` includes `VK_SAMPLER_CREATE_SUBSAMPLED_BIT_EXT`, then `compareEnable` must be `VK_FALSE`.

- If `flags` includes `VK_SAMPLER_CREATE_SUBSAMPLED_BIT_EXT`, then `unnormalizedCoordinates` must be `VK_FALSE`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkSamplerReductionModeCreateInfo or VkSamplerYcbcrConversionInfo

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be a valid combination of VkSamplerCreateFlagBits values

- `magFilter` must be a valid VkFilter value

- `minFilter` must be a valid VkFilter value

- `mipmapMode` must be a valid VkSamplerMipmapMode value

- `addressModeU` must be a valid VkSamplerAddressMode value

- `addressModeV` must be a valid VkSamplerAddressMode value

- `addressModeW` must be a valid VkSamplerAddressMode value

Bits which can be set in VkSamplerCreateInfo::`flags`, specifying additional parameters of a sampler, are:

    typedef enum VkSamplerCreateFlagBits {
        VK_SAMPLER_CREATE_SUBSAMPLED_BIT_EXT = 0x00000001,
        VK_SAMPLER_CREATE_SUBSAMPLED_COARSE_RECONSTRUCTION_BIT_EXT = 0x00000002,
        VK_SAMPLER_CREATE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkSamplerCreateFlagBits;

- `VK_SAMPLER_CREATE_SUBSAMPLED_BIT_EXT` specifies that the sampler will read from an image created with `flags` containing `VK_IMAGE_CREATE_SUBSAMPLED_BIT_EXT`.

- `VK_SAMPLER_CREATE_SUBSAMPLED_COARSE_RECONSTRUCTION_BIT_EXT` specifies that the implementation may use approximations when reconstructing a full color value for texture access from a subsampled image.

| Note The approximations used when `VK_SAMPLER_CREATE_SUBSAMPLED_COARSE_RECONSTRUCTION_BIT_EXT` is specified are implementation defined. Some implementations may interpolate between fragment density levels in a subsampled image. In that case, this bit may be used to decide whether the interpolation factors are calculated per fragment or at a coarser granularity.

    typedef VkFlags VkSamplerCreateFlags;

`VkSamplerCreateFlags` is a bitmask type for setting a mask of zero or more VkSamplerCreateFlagBits.

The `VkSamplerReductionModeCreateInfo` structure is defined as:

    typedef struct VkSamplerReductionModeCreateInfo {
        VkStructureType           sType;
        const void*               pNext;
        VkSamplerReductionMode    reductionMode;
    } VkSamplerReductionModeCreateInfo;

or the equivalent

    typedef VkSamplerReductionModeCreateInfo VkSamplerReductionModeCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `reductionMode` is a VkSamplerReductionMode value controlling how texture filtering combines texel values.

If the `pNext` chain of VkSamplerCreateInfo includes a `VkSamplerReductionModeCreateInfo` structure, then that structure includes a mode that controls how texture filtering combines texel values.

If this structure is not present, `reductionMode` is considered to be `VK_SAMPLER_REDUCTION_MODE_WEIGHTED_AVERAGE`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SAMPLER_REDUCTION_MODE_CREATE_INFO`

- `reductionMode` must be a valid VkSamplerReductionMode value

Reduction modes are specified by VkSamplerReductionMode, which takes values:

    typedef enum VkSamplerReductionMode {
        VK_SAMPLER_REDUCTION_MODE_WEIGHTED_AVERAGE = 0,
        VK_SAMPLER_REDUCTION_MODE_MIN = 1,
        VK_SAMPLER_REDUCTION_MODE_MAX = 2,
        VK_SAMPLER_REDUCTION_MODE_WEIGHTED_AVERAGE_EXT = VK_SAMPLER_REDUCTION_MODE_WEIGHTED_AVERAGE,
        VK_SAMPLER_REDUCTION_MODE_MIN_EXT = VK_SAMPLER_REDUCTION_MODE_MIN,
        VK_SAMPLER_REDUCTION_MODE_MAX_EXT = VK_SAMPLER_REDUCTION_MODE_MAX,
        VK_SAMPLER_REDUCTION_MODE_MAX_ENUM = 0x7FFFFFFF
    } VkSamplerReductionMode;

or the equivalent

    typedef VkSamplerReductionMode VkSamplerReductionModeEXT;

- `VK_SAMPLER_REDUCTION_MODE_WEIGHTED_AVERAGE` specifies that texel values are combined by computing a weighted average of values in the footprint, using weights as specified in the image operations chapter.

- `VK_SAMPLER_REDUCTION_MODE_MIN` specifies that texel values are combined by taking the component-wise minimum of values in the footprint with non-zero weights.

- `VK_SAMPLER_REDUCTION_MODE_MAX` specifies that texel values are combined by taking the component-wise maximum of values in the footprint with non-zero weights.

Possible values of the VkSamplerCreateInfo::`magFilter` and `minFilter` parameters, specifying filters used for texture lookups, are:

    typedef enum VkFilter {
        VK_FILTER_NEAREST = 0,
        VK_FILTER_LINEAR = 1,
        VK_FILTER_CUBIC_IMG = 1000015000,
        VK_FILTER_CUBIC_EXT = VK_FILTER_CUBIC_IMG,
        VK_FILTER_MAX_ENUM = 0x7FFFFFFF
    } VkFilter;

- `VK_FILTER_NEAREST` specifies nearest filtering.

- `VK_FILTER_LINEAR` specifies linear filtering.

- `VK_FILTER_CUBIC_EXT` specifies cubic filtering.

These filters are described in detail in Texel Filtering.

Possible values of the VkSamplerCreateInfo::`mipmapMode`, specifying the mipmap mode used for texture lookups, are:

    typedef enum VkSamplerMipmapMode {
        VK_SAMPLER_MIPMAP_MODE_NEAREST = 0,
        VK_SAMPLER_MIPMAP_MODE_LINEAR = 1,
        VK_SAMPLER_MIPMAP_MODE_MAX_ENUM = 0x7FFFFFFF
    } VkSamplerMipmapMode;

- `VK_SAMPLER_MIPMAP_MODE_NEAREST` specifies nearest filtering.

- `VK_SAMPLER_MIPMAP_MODE_LINEAR` specifies linear filtering.

These modes are described in detail in Texel Filtering.

Possible values of the VkSamplerCreateInfo::`addressMode*` parameters, specifying the behavior of sampling with coordinates outside the range [0,1] for the respective u, v, or w coordinate as defined in the Wrapping Operation section, are:

    typedef enum VkSamplerAddressMode {
        VK_SAMPLER_ADDRESS_MODE_REPEAT = 0,
        VK_SAMPLER_ADDRESS_MODE_MIRRORED_REPEAT = 1,
        VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE = 2,
        VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER = 3,
        VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE = 4,
        VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE_KHR = VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE,
        VK_SAMPLER_ADDRESS_MODE_MAX_ENUM = 0x7FFFFFFF
    } VkSamplerAddressMode;

- `VK_SAMPLER_ADDRESS_MODE_REPEAT` specifies that the repeat wrap mode will be used.

- `VK_SAMPLER_ADDRESS_MODE_MIRRORED_REPEAT` specifies that the mirrored repeat wrap mode will be used.

- `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE` specifies that the clamp to edge wrap mode will be used.

- `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER` specifies that the clamp to border wrap mode will be used.

- `VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE` specifies that the mirror clamp to edge wrap mode will be used. This is only valid if samplerMirrorClampToEdge is enabled, or if the `VK_KHR_sampler_mirror_clamp_to_edge` extension is enabled.

Possible values of VkSamplerCreateInfo::`borderColor`, specifying the border color used for texture lookups, are:

    typedef enum VkBorderColor {
        VK_BORDER_COLOR_FLOAT_TRANSPARENT_BLACK = 0,
        VK_BORDER_COLOR_INT_TRANSPARENT_BLACK = 1,
        VK_BORDER_COLOR_FLOAT_OPAQUE_BLACK = 2,
        VK_BORDER_COLOR_INT_OPAQUE_BLACK = 3,
        VK_BORDER_COLOR_FLOAT_OPAQUE_WHITE = 4,
        VK_BORDER_COLOR_INT_OPAQUE_WHITE = 5,
        VK_BORDER_COLOR_MAX_ENUM = 0x7FFFFFFF
    } VkBorderColor;

- `VK_BORDER_COLOR_FLOAT_TRANSPARENT_BLACK` specifies a transparent, floating-point format, black color.

- `VK_BORDER_COLOR_INT_TRANSPARENT_BLACK` specifies a transparent, integer format, black color.

- `VK_BORDER_COLOR_FLOAT_OPAQUE_BLACK` specifies an opaque, floating-point format, black color.

- `VK_BORDER_COLOR_INT_OPAQUE_BLACK` specifies an opaque, integer format, black color.

- `VK_BORDER_COLOR_FLOAT_OPAQUE_WHITE` specifies an opaque, floating-point format, white color.

- `VK_BORDER_COLOR_INT_OPAQUE_WHITE` specifies an opaque, integer format, white color.

These colors are described in detail in Texel Replacement.

To destroy a sampler, call:

    void vkDestroySampler(
        VkDevice                                    device,
        VkSampler                                   sampler,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that destroys the sampler.

- `sampler` is the sampler to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage

- All submitted commands that refer to `sampler` must have completed execution

- If `VkAllocationCallbacks` were provided when `sampler` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `sampler` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `sampler` is not VK_NULL_HANDLE, `sampler` must be a valid VkSampler handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- If `sampler` is a valid handle, it must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `sampler` must be externally synchronized

### 12.1. Sampler Y′CBCR conversion

To create a sampler with Y′CBCR conversion enabled, add a VkSamplerYcbcrConversionInfo structure to the `pNext` chain of the VkSamplerCreateInfo structure. To create a sampler Y′CBCR conversion, the `samplerYcbcrConversion` feature must be enabled. Conversion must be fixed at pipeline creation time, through use of a combined image sampler with an immutable sampler in `VkDescriptorSetLayoutBinding`.

A VkSamplerYcbcrConversionInfo must be provided for samplers to be used with image views that access `VK_IMAGE_ASPECT_COLOR_BIT` if the format appears in Formats requiring sampler Y′CBCR conversion for `VK_IMAGE_ASPECT_COLOR_BIT` image views , or if the image view has an external format .

The `VkSamplerYcbcrConversionInfo` structure is defined as:

    typedef struct VkSamplerYcbcrConversionInfo {
        VkStructureType             sType;
        const void*                 pNext;
        VkSamplerYcbcrConversion    conversion;
    } VkSamplerYcbcrConversionInfo;

or the equivalent

    typedef VkSamplerYcbcrConversionInfo VkSamplerYcbcrConversionInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `conversion` is a VkSamplerYcbcrConversion handle created with vkCreateSamplerYcbcrConversion.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_INFO`

- `conversion` must be a valid VkSamplerYcbcrConversion handle

A sampler Y′CBCR conversion is an opaque representation of a device-specific sampler Y′CBCR conversion description, represented as a `VkSamplerYcbcrConversion` handle:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkSamplerYcbcrConversion)

or the equivalent

    typedef VkSamplerYcbcrConversion VkSamplerYcbcrConversionKHR;

To create a VkSamplerYcbcrConversion, call:

    VkResult vkCreateSamplerYcbcrConversion(
        VkDevice                                    device,
        const VkSamplerYcbcrConversionCreateInfo*   pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkSamplerYcbcrConversion*                   pYcbcrConversion);

or the equivalent command

    VkResult vkCreateSamplerYcbcrConversionKHR(
        VkDevice                                    device,
        const VkSamplerYcbcrConversionCreateInfo*   pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkSamplerYcbcrConversion*                   pYcbcrConversion);

- `device` is the logical device that creates the sampler Y′CBCR conversion.

- `pCreateInfo` is a pointer to a VkSamplerYcbcrConversionCreateInfo structure specifying the requested sampler Y′CBCR conversion.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pYcbcrConversion` is a pointer to a VkSamplerYcbcrConversion handle in which the resulting sampler Y′CBCR conversion is returned.

The interpretation of the configured sampler Y′CBCR conversion is described in more detail in the description of sampler Y′CBCR conversion in the Image Operations chapter.

Valid Usage

- The sampler Y′CBCR conversion feature must be enabled

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkSamplerYcbcrConversionCreateInfo structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pYcbcrConversion` must be a valid pointer to a VkSamplerYcbcrConversion handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkSamplerYcbcrConversionCreateInfo` structure is defined as:

    typedef struct VkSamplerYcbcrConversionCreateInfo {
        VkStructureType                  sType;
        const void*                      pNext;
        VkFormat                         format;
        VkSamplerYcbcrModelConversion    ycbcrModel;
        VkSamplerYcbcrRange              ycbcrRange;
        VkComponentMapping               components;
        VkChromaLocation                 xChromaOffset;
        VkChromaLocation                 yChromaOffset;
        VkFilter                         chromaFilter;
        VkBool32                         forceExplicitReconstruction;
    } VkSamplerYcbcrConversionCreateInfo;

or the equivalent

    typedef VkSamplerYcbcrConversionCreateInfo VkSamplerYcbcrConversionCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `format` is the format of the image from which color information will be retrieved.

- `ycbcrModel` describes the color matrix for conversion between color models.

- `ycbcrRange` describes whether the encoded values have headroom and foot room, or whether the encoding uses the full numerical range.

- `components` applies a swizzle based on VkComponentSwizzle enums prior to range expansion and color model conversion.

- `xChromaOffset` describes the sample location associated with downsampled chroma channels in the x dimension. `xChromaOffset` has no effect for formats in which chroma channels are the same resolution as the luma channel.

- `yChromaOffset` describes the sample location associated with downsampled chroma channels in the y dimension. `yChromaOffset` has no effect for formats in which the chroma channels are not downsampled vertically.

- `chromaFilter` is the filter for chroma reconstruction.

- `forceExplicitReconstruction` can be used to ensure that reconstruction is done explicitly, if supported.

| Note Setting `forceExplicitReconstruction` to `VK_TRUE` may have a performance penalty on implementations where explicit reconstruction is not the default mode of operation. If `format` supports `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_BIT` the `forceExplicitReconstruction` value behaves as if it was set to `VK_TRUE`.

If the `pNext` chain includes a VkExternalFormatANDROID structure with non-zero `externalFormat` member, the sampler Y′CBCR conversion object represents an external format conversion, and `format` must be `VK_FORMAT_UNDEFINED`. Such conversions must only be used to sample image views with a matching external format. When creating an external format conversion, the value of `components` is ignored.

Valid Usage

- If an external format conversion is being created, `format` must be `VK_FORMAT_UNDEFINED`, otherwise it must not be `VK_FORMAT_UNDEFINED`.

- `format` must support `VK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BIT` or `VK_FORMAT_FEATURE_COSITED_CHROMA_SAMPLES_BIT`

- If the format does not support `VK_FORMAT_FEATURE_COSITED_CHROMA_SAMPLES_BIT`, `xChromaOffset` and `yChromaOffset` must not be `VK_CHROMA_LOCATION_COSITED_EVEN`

- If the format does not support `VK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BIT`, `xChromaOffset` and `yChromaOffset` must not be `VK_CHROMA_LOCATION_MIDPOINT`

- If the format has a `_422` or `_420` suffix, then `components.g` must be `VK_COMPONENT_SWIZZLE_IDENTITY`

- If the format has a `_422` or `_420` suffix, then `components.a` must be `VK_COMPONENT_SWIZZLE_IDENTITY`, `VK_COMPONENT_SWIZZLE_ONE`, or `VK_COMPONENT_SWIZZLE_ZERO`

- If the format has a `_422` or `_420` suffix, then `components.r` must be `VK_COMPONENT_SWIZZLE_IDENTITY` or `VK_COMPONENT_SWIZZLE_B`

- If the format has a `_422` or `_420` suffix, then `components.b` must be `VK_COMPONENT_SWIZZLE_IDENTITY` or `VK_COMPONENT_SWIZZLE_R`

- If the format has a `_422` or `_420` suffix, and if either `components.r` or `components.b` is `VK_COMPONENT_SWIZZLE_IDENTITY`, both values must be `VK_COMPONENT_SWIZZLE_IDENTITY`

- If `ycbcrModel` is not `VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY`, then `components.r`, `components.g`, and `components.b` must correspond to channels of the `format`; that is, `components.r`, `components.g`, and `components.b` must not be `VK_COMPONENT_SWIZZLE_ZERO` or `VK_COMPONENT_SWIZZLE_ONE`, and must not correspond to a channel which contains zero or one as a consequence of conversion to RGBA

- If `ycbcrRange` is `VK_SAMPLER_YCBCR_RANGE_ITU_NARROW` then the R, G and B channels obtained by applying the `component` swizzle to `format` must each have a bit-depth greater than or equal to 8.

- If the format does not support `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_FORCEABLE_BIT` `forceExplicitReconstruction` must be `VK_FALSE`

- If the format does not support `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_LINEAR_FILTER_BIT`, `chromaFilter` must not be `VK_FILTER_LINEAR`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_CREATE_INFO`

- `pNext` must be `NULL` or a pointer to a valid instance of VkExternalFormatANDROID

- The `sType` value of each struct in the `pNext` chain must be unique

- `format` must be a valid VkFormat value

- `ycbcrModel` must be a valid VkSamplerYcbcrModelConversion value

- `ycbcrRange` must be a valid VkSamplerYcbcrRange value

- `components` must be a valid VkComponentMapping structure

- `xChromaOffset` must be a valid VkChromaLocation value

- `yChromaOffset` must be a valid VkChromaLocation value

- `chromaFilter` must be a valid VkFilter value

If `chromaFilter` is `VK_FILTER_NEAREST`, chroma samples are reconstructed to luma channel resolution using nearest-neighbour sampling. Otherwise, chroma samples are reconstructed using interpolation. More details can be found in the description of sampler Y′CBCR conversion in the Image Operations chapter.

VkSamplerYcbcrModelConversion defines the conversion from the source color model to the shader color model. Possible values are:

    typedef enum VkSamplerYcbcrModelConversion {
        VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY = 0,
        VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_IDENTITY = 1,
        VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_709 = 2,
        VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_601 = 3,
        VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_2020 = 4,
        VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY_KHR = VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY,
        VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_IDENTITY_KHR = VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_IDENTITY,
        VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_709_KHR = VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_709,
        VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_601_KHR = VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_601,
        VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_2020_KHR = VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_2020,
        VK_SAMPLER_YCBCR_MODEL_CONVERSION_MAX_ENUM = 0x7FFFFFFF
    } VkSamplerYcbcrModelConversion;

or the equivalent

    typedef VkSamplerYcbcrModelConversion VkSamplerYcbcrModelConversionKHR;

- `VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY` specifies that the input values to the conversion are unmodified.

- `VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_IDENTITY` specifies no model conversion but the inputs are range expanded as for Y′CBCR.

- `VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_709` specifies the color model conversion from Y′CBCR to R′G′B′ defined in BT.709 and described in the “BT.709 Y’CBCR conversion” section of the Khronos Data Format Specification.

- `VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_601` specifies the color model conversion from Y′CBCR to R′G′B′ defined in BT.601 and described in the “BT.601 Y’CBCR conversion” section of the Khronos Data Format Specification.

- `VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_2020` specifies the color model conversion from Y′CBCR to R′G′B′ defined in BT.2020 and described in the “BT.2020 Y’CBCR conversion” section of the Khronos Data Format Specification.

In the `VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_*` color models, for the input to the sampler Y′CBCR range expansion and model conversion:

- the Y (Y′ luma) channel corresponds to the G channel of an RGB image.

- the CB (CB or “U” blue color difference) channel corresponds to the B channel of an RGB image.

- the CR (CR or “V” red color difference) channel corresponds to the R channel of an RGB image.

- the alpha channel, if present, is not modified by color model conversion.

These rules reflect the mapping of channels after the channel swizzle operation (controlled by VkSamplerYcbcrConversionCreateInfo::`components`).

| Note For example, an “YUVA” 32-bit format comprising four 8-bit channels can be implemented as `VK_FORMAT_R8G8B8A8_UNORM` with a component mapping: `components.a` = `VK_COMPONENT_SWIZZLE_IDENTITY` `components.r` = `VK_COMPONENT_SWIZZLE_B` `components.g` = `VK_COMPONENT_SWIZZLE_R` `components.b` = `VK_COMPONENT_SWIZZLE_G`

The VkSamplerYcbcrRange enum describes whether color channels are encoded using the full range of numerical values or whether values are reserved for headroom and foot room. VkSamplerYcbcrRange is defined as:

    typedef enum VkSamplerYcbcrRange {
        VK_SAMPLER_YCBCR_RANGE_ITU_FULL = 0,
        VK_SAMPLER_YCBCR_RANGE_ITU_NARROW = 1,
        VK_SAMPLER_YCBCR_RANGE_ITU_FULL_KHR = VK_SAMPLER_YCBCR_RANGE_ITU_FULL,
        VK_SAMPLER_YCBCR_RANGE_ITU_NARROW_KHR = VK_SAMPLER_YCBCR_RANGE_ITU_NARROW,
        VK_SAMPLER_YCBCR_RANGE_MAX_ENUM = 0x7FFFFFFF
    } VkSamplerYcbcrRange;

or the equivalent

    typedef VkSamplerYcbcrRange VkSamplerYcbcrRangeKHR;

- `VK_SAMPLER_YCBCR_RANGE_ITU_FULL` specifies that the full range of the encoded values are valid and interpreted according to the ITU “full range” quantization rules.

- `VK_SAMPLER_YCBCR_RANGE_ITU_NARROW` specifies that headroom and foot room are reserved in the numerical range of encoded values, and the remaining values are expanded according to the ITU “narrow range” quantization rules.

The formulae for these conversions is described in the Sampler Y′CBCR Range Expansion section of the Image Operations chapter.

No range modification takes place if `ycbcrModel` is `VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY`; the `ycbcrRange` field of `VkSamplerYcbcrConversionCreateInfo` is ignored in this case.

The VkChromaLocation enum defines the location of downsampled chroma channel samples relative to the luma samples, and is defined as:

    typedef enum VkChromaLocation {
        VK_CHROMA_LOCATION_COSITED_EVEN = 0,
        VK_CHROMA_LOCATION_MIDPOINT = 1,
        VK_CHROMA_LOCATION_COSITED_EVEN_KHR = VK_CHROMA_LOCATION_COSITED_EVEN,
        VK_CHROMA_LOCATION_MIDPOINT_KHR = VK_CHROMA_LOCATION_MIDPOINT,
        VK_CHROMA_LOCATION_MAX_ENUM = 0x7FFFFFFF
    } VkChromaLocation;

or the equivalent

    typedef VkChromaLocation VkChromaLocationKHR;

- `VK_CHROMA_LOCATION_COSITED_EVEN` specifies that downsampled chroma samples are aligned with luma samples with even coordinates.

- `VK_CHROMA_LOCATION_MIDPOINT` specifies that downsampled chroma samples are located half way between each even luma sample and the nearest higher odd luma sample.

To destroy a sampler Y′CBCR conversion, call:

    void vkDestroySamplerYcbcrConversion(
        VkDevice                                    device,
        VkSamplerYcbcrConversion                    ycbcrConversion,
        const VkAllocationCallbacks*                pAllocator);

or the equivalent command

    void vkDestroySamplerYcbcrConversionKHR(
        VkDevice                                    device,
        VkSamplerYcbcrConversion                    ycbcrConversion,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that destroys the Y′CBCR conversion.

- `ycbcrConversion` is the conversion to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `ycbcrConversion` is not VK_NULL_HANDLE, `ycbcrConversion` must be a valid VkSamplerYcbcrConversion handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- If `ycbcrConversion` is a valid handle, it must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `ycbcrConversion` must be externally synchronized

## 13. Resource Descriptors

A descriptor is an opaque data structure representing a shader resource such as a buffer, buffer view, image view, sampler, or combined image sampler. Descriptors are organised into descriptor sets, which are bound during command recording for use in subsequent draw commands. The arrangement of content in each descriptor set is determined by a descriptor set layout, which determines what descriptors can be stored within it. The sequence of descriptor set layouts that can be used by a pipeline is specified in a pipeline layout. Each pipeline object can use up to `maxBoundDescriptorSets` (see Limits) descriptor sets.

Shaders access resources via variables decorated with a descriptor set and binding number that link them to a descriptor in a descriptor set. The shader interface mapping to bound descriptor sets is described in the Shader Resource Interface section.

Shaders can also access buffers without going through descriptors by using Physical Storage Buffer Access to access them through 64-bit addresses.

### 13.1. Descriptor Types

There are a number of different types of descriptor supported by Vulkan, corresponding to different resources or usage. The following sections describe the API definitions of each descriptor type. The mapping of each type to SPIR-V is listed in the Shader Resource and Descriptor Type Correspondence and Shader Resource and Storage Class Correspondence tables in the Shader Interfaces chapter.

#### 13.1.1. Storage Image

A storage image (`VK_DESCRIPTOR_TYPE_STORAGE_IMAGE`) is a descriptor type associated with an image resource via an image view that load, store, and atomic operations can be performed on.

Storage image loads are supported in all shader stages for image views whose format features contain `VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT`.

Stores to storage images are supported in compute shaders for image views whose format features contain `VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT`.

Atomic operations on storage images are supported in compute shaders for image views whose format features contain `VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT`.

When the `fragmentStoresAndAtomics` feature is enabled, stores and atomic operations are also supported for storage images in fragment shaders with the same set of image formats as supported in compute shaders. When the `vertexPipelineStoresAndAtomics` feature is enabled, stores and atomic operations are also supported in vertex, tessellation, and geometry shaders with the same set of image formats as supported in compute shaders.

The image subresources for a storage image must be in the `VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR` or `VK_IMAGE_LAYOUT_GENERAL` layout in order to access its data in a shader.

#### 13.1.2. Sampler

A sampler descriptor (`VK_DESCRIPTOR_TYPE_SAMPLER`) is a descriptor type associated with a sampler object, used to control the behavior of sampling operations performed on a sampled image.

#### 13.1.3. Sampled Image

A sampled image (`VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE`) is a descriptor type associated with an image resource via an image view that sampling operations can be performed on.

Shaders combine a sampled image variable and a sampler variable to perform sampling operations.

Sampled images are supported in all shader stages for image views whose format features contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT`.

The image subresources for a sampled image must be in the `VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR`, `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL`, or `VK_IMAGE_LAYOUT_GENERAL` layout in order to access its data in a shader.

#### 13.1.4. Combined Image Sampler

A combined image sampler (`VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`) is a single descriptor type associated with both a sampler and an image resource, combining both a sampler and sampled image descriptor into a single descriptor.

If the descriptor refers to a sampler that performs Y′CBCR conversion or samples a subsampled image, the sampler must only be used to sample the image in the same descriptor. Otherwise, the sampler and image in this type of descriptor can be used freely with any other samplers and images.

The image subresources for a combined image sampler must be in the `VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR`, `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL`, or `VK_IMAGE_LAYOUT_GENERAL` layout in order to access its data in a shader.

| Note On some implementations, it may be more efficient to sample from an image using a combination of sampler and sampled image that are stored together in the descriptor set in a combined descriptor.

#### 13.1.5. Uniform Texel Buffer

A uniform texel buffer (`VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER`) is a descriptor type associated with a buffer resource via a buffer view that formatted load operations can be performed on.

Uniform texel buffers define a tightly-packed 1-dimensional linear array of texels, with texels going through format conversion when read in a shader in the same way as they are for an image.

Load operations from uniform texel buffers are supported in all shader stages for image formats which report support for the `VK_FORMAT_FEATURE_UNIFORM_TEXEL_BUFFER_BIT` feature bit via vkGetPhysicalDeviceFormatProperties in VkFormatProperties::`bufferFeatures`.

#### 13.1.6. Storage Texel Buffer

A storage texel buffer (`VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER`) is a descriptor type associated with a buffer resource via a buffer view that formatted load, store, and atomic operations can be performed on.

Storage texel buffers define a tightly-packed 1-dimensional linear array of texels, with texels going through format conversion when read in a shader in the same way as they are for an image. Unlike uniform texel buffers, these buffers can also be written to in the same way as for storage images.

Storage texel buffer loads are supported in all shader stages for texel buffer formats which report support for the `VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_BIT` feature bit via vkGetPhysicalDeviceFormatProperties in VkFormatProperties::`bufferFeatures`.

Stores to storage texel buffers are supported in compute shaders for texel buffer formats which report support for the `VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_BIT` feature via vkGetPhysicalDeviceFormatProperties in VkFormatProperties::`bufferFeatures`.

Atomic operations on storage texel buffers are supported in compute shaders for texel buffer formats which report support for the `VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_ATOMIC_BIT` feature via vkGetPhysicalDeviceFormatProperties in VkFormatProperties::`bufferFeatures`.

When the `fragmentStoresAndAtomics` feature is enabled, stores and atomic operations are also supported for storage texel buffers in fragment shaders with the same set of texel buffer formats as supported in compute shaders. When the `vertexPipelineStoresAndAtomics` feature is enabled, stores and atomic operations are also supported in vertex, tessellation, and geometry shaders with the same set of texel buffer formats as supported in compute shaders.

#### 13.1.7. Storage Buffer

A storage buffer (`VK_DESCRIPTOR_TYPE_STORAGE_BUFFER`) is a descriptor type associated with a buffer resource directly, described in a shader as a structure with various members that load, store, and atomic operations can be performed on.

| Note Atomic operations can only be performed on members of certain types as defined in the SPIR-V environment appendix.

#### 13.1.8. Uniform Buffer

A uniform buffer (`VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER`) is a descriptor type associated with a buffer resource directly, described in a shader as a structure with various members that load operations can be performed on.

#### 13.1.9. Dynamic Uniform Buffer

A dynamic uniform buffer (`VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC`) is almost identical to a uniform buffer, and differs only in how the offset into the buffer is specified. The base offset calculated by the VkDescriptorBufferInfo when initially updating the descriptor set is added to a dynamic offset when binding the descriptor set.

#### 13.1.10. Dynamic Storage Buffer

A dynamic storage buffer (`VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC`) is almost identical to a storage buffer, and differs only in how the offset into the buffer is specified. The base offset calculated by the VkDescriptorBufferInfo when initially updating the descriptor set is added to a dynamic offset when binding the descriptor set.

#### 13.1.11. Inline Uniform Block

An inline uniform block (`VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT`) is almost identical to a uniform buffer, and differs only in taking its storage directly from the encompassing descriptor set instead of being backed by buffer memory. It is typically used to access a small set of constant data that does not require the additional flexibility provided by the indirection enabled when using a uniform buffer where the descriptor and the referenced buffer memory are decoupled. Compared to push constants, they allow reusing the same set of constant data across multiple disjoint sets of draw and dispatch commands.

Inline uniform block descriptors cannot be aggregated into arrays. Instead, the array size specified for an inline uniform block descriptor binding specifies the binding’s capacity in bytes.

#### 13.1.12. Input Attachment

An input attachment (`VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT`) is a descriptor type associated with an image resource via an image view that can be used for framebuffer local load operations in fragment shaders.

All image formats that are supported for color attachments (`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT`) or depth/stencil attachments (`VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT`) for a given image tiling mode are also supported for input attachments.

The image subresources for an input attachment must be in the `VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR`, `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL`, or `VK_IMAGE_LAYOUT_GENERAL` layout in order to access its data in a shader.

#### 13.1.13. Acceleration Structure

An acceleration structure (`VK_DESCRIPTOR_TYPE_ACCELERATION_STRUCTURE_KHR`) is a descriptor type that is used to retrieve scene geometry from within shaders bound to ray tracing pipelines. Shaders have read-only access to the memory.

### 13.2. Descriptor Sets

Descriptors are grouped together into descriptor set objects. A descriptor set object is an opaque object containing storage for a set of descriptors, where the types and number of descriptors is defined by a descriptor set layout. The layout object may be used to define the association of each descriptor binding with memory or other implementation resources. The layout is used both for determining the resources that need to be associated with the descriptor set, and determining the interface between shader stages and shader resources.

#### 13.2.1. Descriptor Set Layout

A descriptor set layout object is defined by an array of zero or more descriptor bindings. Each individual descriptor binding is specified by a descriptor type, a count (array size) of the number of descriptors in the binding, a set of shader stages that can access the binding, and (if using immutable samplers) an array of sampler descriptors.

Descriptor set layout objects are represented by `VkDescriptorSetLayout` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkDescriptorSetLayout)

To create descriptor set layout objects, call:

    VkResult vkCreateDescriptorSetLayout(
        VkDevice                                    device,
        const VkDescriptorSetLayoutCreateInfo*      pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkDescriptorSetLayout*                      pSetLayout);

- `device` is the logical device that creates the descriptor set layout.

- `pCreateInfo` is a pointer to a VkDescriptorSetLayoutCreateInfo structure specifying the state of the descriptor set layout object.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pSetLayout` is a pointer to a VkDescriptorSetLayout handle in which the resulting descriptor set layout object is returned.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkDescriptorSetLayoutCreateInfo structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pSetLayout` must be a valid pointer to a VkDescriptorSetLayout handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

Information about the descriptor set layout is passed in a `VkDescriptorSetLayoutCreateInfo` structure:

    typedef struct VkDescriptorSetLayoutCreateInfo {
        VkStructureType                        sType;
        const void*                            pNext;
        VkDescriptorSetLayoutCreateFlags       flags;
        uint32_t                               bindingCount;
        const VkDescriptorSetLayoutBinding*    pBindings;
    } VkDescriptorSetLayoutCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkDescriptorSetLayoutCreateFlagBits specifying options for descriptor set layout creation.

- `bindingCount` is the number of elements in `pBindings`.

- `pBindings` is a pointer to an array of VkDescriptorSetLayoutBinding structures.

Valid Usage

- The VkDescriptorSetLayoutBinding::`binding` members of the elements of the `pBindings` array must each have different values.

- If `flags` contains `VK_DESCRIPTOR_SET_LAYOUT_CREATE_PUSH_DESCRIPTOR_BIT_KHR`, then all elements of `pBindings` must not have a `descriptorType` of `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC` or `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC`

- If `flags` contains `VK_DESCRIPTOR_SET_LAYOUT_CREATE_PUSH_DESCRIPTOR_BIT_KHR`, then all elements of `pBindings` must not have a `descriptorType` of `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT`

- If `flags` contains `VK_DESCRIPTOR_SET_LAYOUT_CREATE_PUSH_DESCRIPTOR_BIT_KHR`, then the total number of elements of all bindings must be less than or equal to VkPhysicalDevicePushDescriptorPropertiesKHR::`maxPushDescriptors`

- If any binding has the `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT` bit set, `flags` must include `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT`

- If any binding has the `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT` bit set, then all bindings must not have `descriptorType` of `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC` or `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO`

- `pNext` must be `NULL` or a pointer to a valid instance of VkDescriptorSetLayoutBindingFlagsCreateInfo

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be a valid combination of VkDescriptorSetLayoutCreateFlagBits values

- If `bindingCount` is not `0`, `pBindings` must be a valid pointer to an array of `bindingCount` valid VkDescriptorSetLayoutBinding structures

Bits which can be set in VkDescriptorSetLayoutCreateInfo::`flags` to specify options for descriptor set layout are:

    typedef enum VkDescriptorSetLayoutCreateFlagBits {
        VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT = 0x00000002,
        VK_DESCRIPTOR_SET_LAYOUT_CREATE_PUSH_DESCRIPTOR_BIT_KHR = 0x00000001,
        VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXT = VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT,
        VK_DESCRIPTOR_SET_LAYOUT_CREATE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkDescriptorSetLayoutCreateFlagBits;

- `VK_DESCRIPTOR_SET_LAYOUT_CREATE_PUSH_DESCRIPTOR_BIT_KHR` specifies that descriptor sets must not be allocated using this layout, and descriptors are instead pushed by vkCmdPushDescriptorSetKHR.

- `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` specifies that descriptor sets using this layout must be allocated from a descriptor pool created with the `VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT` bit set. Descriptor set layouts created with this bit set have alternate limits for the maximum number of descriptors per-stage and per-pipeline layout. The non-UpdateAfterBind limits only count descriptors in sets created without this flag. The UpdateAfterBind limits count all descriptors, but the limits may be higher than the non-UpdateAfterBind limits.

    typedef VkFlags VkDescriptorSetLayoutCreateFlags;

`VkDescriptorSetLayoutCreateFlags` is a bitmask type for setting a mask of zero or more VkDescriptorSetLayoutCreateFlagBits.

The `VkDescriptorSetLayoutBinding` structure is defined as:

    typedef struct VkDescriptorSetLayoutBinding {
        uint32_t              binding;
        VkDescriptorType      descriptorType;
        uint32_t              descriptorCount;
        VkShaderStageFlags    stageFlags;
        const VkSampler*      pImmutableSamplers;
    } VkDescriptorSetLayoutBinding;

- `binding` is the binding number of this entry and corresponds to a resource of the same binding number in the shader stages.

- `descriptorType` is a VkDescriptorType specifying which type of resource descriptors are used for this binding.

- `descriptorCount` is the number of descriptors contained in the binding, accessed in a shader as an array , except if `descriptorType` is `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` in which case `descriptorCount` is the size in bytes of the inline uniform block . If `descriptorCount` is zero this binding entry is reserved and the resource must not be accessed from any stage via this binding within any pipeline using the set layout.

- `stageFlags` member is a bitmask of VkShaderStageFlagBits specifying which pipeline shader stages can access a resource for this binding. `VK_SHADER_STAGE_ALL` is a shorthand specifying that all defined shader stages, including any additional stages defined by extensions, can access the resource.

  If a shader stage is not included in `stageFlags`, then a resource must not be accessed from that stage via this binding within any pipeline using the set layout. Other than input attachments which are limited to the fragment shader, there are no limitations on what combinations of stages can use a descriptor binding, and in particular a binding can be used by both graphics stages and the compute stage.

- `pImmutableSamplers` affects initialization of samplers. If `descriptorType` specifies a `VK_DESCRIPTOR_TYPE_SAMPLER` or `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER` type descriptor, then `pImmutableSamplers` can be used to initialize a set of immutable samplers. Immutable samplers are permanently bound into the set layout and must not be changed; updating a `VK_DESCRIPTOR_TYPE_SAMPLER` descriptor with immutable samplers is not allowed and updates to a `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER` descriptor with immutable samplers does not modify the samplers (the image views are updated, but the sampler updates are ignored). If `pImmutableSamplers` is not `NULL`, then it points to an array of sampler handles that will be copied into the set layout and used for the corresponding binding. Only the sampler handles are copied; the sampler objects must not be destroyed before the final use of the set layout and any descriptor pools and sets created using it. If `pImmutableSamplers` is `NULL`, then the sampler slots are dynamic and sampler handles must be bound into descriptor sets using this layout. If `descriptorType` is not one of these descriptor types, then `pImmutableSamplers` is ignored.

The above layout definition allows the descriptor bindings to be specified sparsely such that not all binding numbers between 0 and the maximum binding number need to be specified in the `pBindings` array. Bindings that are not specified have a `descriptorCount` and `stageFlags` of zero, and the value of `descriptorType` is undefined. However, all binding numbers between 0 and the maximum binding number in the VkDescriptorSetLayoutCreateInfo::`pBindings` array may consume memory in the descriptor set layout even if not all descriptor bindings are used, though it should not consume additional memory from the descriptor pool.

| Note The maximum binding number specified should be as compact as possible to avoid wasted memory.

Valid Usage

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_SAMPLER` or `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, and `descriptorCount` is not `0` and `pImmutableSamplers` is not `NULL`, `pImmutableSamplers` must be a valid pointer to an array of `descriptorCount` valid `VkSampler` handles

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` then `descriptorCount` must be a multiple of `4`

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` then `descriptorCount` must be less than or equal to `VkPhysicalDeviceInlineUniformBlockPropertiesEXT`::`maxInlineUniformBlockSize`

- If `descriptorCount` is not `0`, `stageFlags` must be a valid combination of VkShaderStageFlagBits values

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT` and `descriptorCount` is not `0`, then `stageFlags` must be `0` or `VK_SHADER_STAGE_FRAGMENT_BIT`

Valid Usage (Implicit)

- `descriptorType` must be a valid VkDescriptorType value

If the `pNext` chain of a VkDescriptorSetLayoutCreateInfo structure includes a `VkDescriptorSetLayoutBindingFlagsCreateInfo` structure, then that structure includes an array of flags, one for each descriptor set layout binding.

The VkDescriptorSetLayoutBindingFlagsCreateInfo structure is defined as:

    typedef struct VkDescriptorSetLayoutBindingFlagsCreateInfo {
        VkStructureType                    sType;
        const void*                        pNext;
        uint32_t                           bindingCount;
        const VkDescriptorBindingFlags*    pBindingFlags;
    } VkDescriptorSetLayoutBindingFlagsCreateInfo;

or the equivalent

    typedef VkDescriptorSetLayoutBindingFlagsCreateInfo VkDescriptorSetLayoutBindingFlagsCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `bindingCount` is zero or the number of elements in `pBindingFlags`.

- `pBindingFlags` is a pointer to an array of VkDescriptorBindingFlags bitfields, one for each descriptor set layout binding.

If `bindingCount` is zero or if this structure is not included in the `pNext` chain, the VkDescriptorBindingFlags for each descriptor set layout binding is considered to be zero. Otherwise, the descriptor set layout binding at VkDescriptorSetLayoutCreateInfo::`pBindings`[i] uses the flags in `pBindingFlags`[i].

Valid Usage

- If `bindingCount` is not zero, `bindingCount` must equal VkDescriptorSetLayoutCreateInfo::`bindingCount`

- If VkDescriptorSetLayoutCreateInfo::`flags` includes `VK_DESCRIPTOR_SET_LAYOUT_CREATE_PUSH_DESCRIPTOR_BIT_KHR`, then all elements of `pBindingFlags` must not include `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT`, `VK_DESCRIPTOR_BINDING_UPDATE_UNUSED_WHILE_PENDING_BIT`, or `VK_DESCRIPTOR_BINDING_VARIABLE_DESCRIPTOR_COUNT_BIT`

- If an element of `pBindingFlags` includes `VK_DESCRIPTOR_BINDING_VARIABLE_DESCRIPTOR_COUNT_BIT`, then all other elements of VkDescriptorSetLayoutCreateInfo::`pBindings` must have a smaller value of `binding`

- If VkPhysicalDeviceDescriptorIndexingFeatures::`descriptorBindingUniformBufferUpdateAfterBind` is not enabled, all bindings with descriptor type `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER` must not use `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT`

- If VkPhysicalDeviceDescriptorIndexingFeatures::`descriptorBindingSampledImageUpdateAfterBind` is not enabled, all bindings with descriptor type `VK_DESCRIPTOR_TYPE_SAMPLER`, `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, or `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE` must not use `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT`

- If VkPhysicalDeviceDescriptorIndexingFeatures::`descriptorBindingStorageImageUpdateAfterBind` is not enabled, all bindings with descriptor type `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE` must not use `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT`

- If VkPhysicalDeviceDescriptorIndexingFeatures::`descriptorBindingStorageBufferUpdateAfterBind` is not enabled, all bindings with descriptor type `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER` must not use `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT`

- If VkPhysicalDeviceDescriptorIndexingFeatures::`descriptorBindingUniformTexelBufferUpdateAfterBind` is not enabled, all bindings with descriptor type `VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER` must not use `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT`

- If VkPhysicalDeviceDescriptorIndexingFeatures::`descriptorBindingStorageTexelBufferUpdateAfterBind` is not enabled, all bindings with descriptor type `VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER` must not use `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT`

- If VkPhysicalDeviceInlineUniformBlockFeaturesEXT::`descriptorBindingInlineUniformBlockUpdateAfterBind` is not enabled, all bindings with descriptor type `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` must not use `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT`

- All bindings with descriptor type `VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT`, `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC`, or `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC` must not use `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT`

- If VkPhysicalDeviceDescriptorIndexingFeatures::`descriptorBindingUpdateUnusedWhilePending` is not enabled, all elements of `pBindingFlags` must not include `VK_DESCRIPTOR_BINDING_UPDATE_UNUSED_WHILE_PENDING_BIT`

- If VkPhysicalDeviceDescriptorIndexingFeatures::`descriptorBindingPartiallyBound` is not enabled, all elements of `pBindingFlags` must not include `VK_DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT`

- If VkPhysicalDeviceDescriptorIndexingFeatures::`descriptorBindingVariableDescriptorCount` is not enabled, all elements of `pBindingFlags` must not include `VK_DESCRIPTOR_BINDING_VARIABLE_DESCRIPTOR_COUNT_BIT`

- If an element of `pBindingFlags` includes `VK_DESCRIPTOR_BINDING_VARIABLE_DESCRIPTOR_COUNT_BIT`, that element’s `descriptorType` must not be `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC` or `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_BINDING_FLAGS_CREATE_INFO`

- If `bindingCount` is not `0`, and `pBindingFlags` is not `NULL`, `pBindingFlags` must be a valid pointer to an array of `bindingCount` valid combinations of VkDescriptorBindingFlagBits values

Bits which can be set in each element of VkDescriptorSetLayoutBindingFlagsCreateInfo::`pBindingFlags` to specify options for the corresponding descriptor set layout binding are:

    typedef enum VkDescriptorBindingFlagBits {
        VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT = 0x00000001,
        VK_DESCRIPTOR_BINDING_UPDATE_UNUSED_WHILE_PENDING_BIT = 0x00000002,
        VK_DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT = 0x00000004,
        VK_DESCRIPTOR_BINDING_VARIABLE_DESCRIPTOR_COUNT_BIT = 0x00000008,
        VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT_EXT = VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT,
        VK_DESCRIPTOR_BINDING_UPDATE_UNUSED_WHILE_PENDING_BIT_EXT = VK_DESCRIPTOR_BINDING_UPDATE_UNUSED_WHILE_PENDING_BIT,
        VK_DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT_EXT = VK_DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT,
        VK_DESCRIPTOR_BINDING_VARIABLE_DESCRIPTOR_COUNT_BIT_EXT = VK_DESCRIPTOR_BINDING_VARIABLE_DESCRIPTOR_COUNT_BIT,
        VK_DESCRIPTOR_BINDING_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkDescriptorBindingFlagBits;

or the equivalent

    typedef VkDescriptorBindingFlagBits VkDescriptorBindingFlagBitsEXT;

- `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT` indicates that if descriptors in this binding are updated between when the descriptor set is bound in a command buffer and when that command buffer is submitted to a queue, then the submission will use the most recently set descriptors for this binding and the updates do not invalidate the command buffer. Descriptor bindings created with this flag are also partially exempt from the external synchronization requirement in vkUpdateDescriptorSetWithTemplateKHR and vkUpdateDescriptorSets. Multiple descriptors with this flag set can be updated concurrently in different threads, though the same descriptor must not be updated concurrently by two threads. Descriptors with this flag set can be updated concurrently with the set being bound to a command buffer in another thread, but not concurrently with the set being reset or freed.

- `VK_DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT` indicates that descriptors in this binding that are not dynamically used need not contain valid descriptors at the time the descriptors are consumed. A descriptor is dynamically used if any shader invocation executes an instruction that performs any memory access using the descriptor.

- `VK_DESCRIPTOR_BINDING_UPDATE_UNUSED_WHILE_PENDING_BIT` indicates that descriptors in this binding can be updated after a command buffer has bound this descriptor set, or while a command buffer that uses this descriptor set is pending execution, as long as the descriptors that are updated are not used by those command buffers. If `VK_DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT` is also set, then descriptors can be updated as long as they are not dynamically used by any shader invocations. If `VK_DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT` is not set, then descriptors can be updated as long as they are not statically used by any shader invocations.

- `VK_DESCRIPTOR_BINDING_VARIABLE_DESCRIPTOR_COUNT_BIT` indicates that this descriptor binding has a variable size that will be specified when a descriptor set is allocated using this layout. The value of `descriptorCount` is treated as an upper bound on the size of the binding. This must only be used for the last binding in the descriptor set layout (i.e. the binding with the largest value of `binding`). For the purposes of counting against limits such as `maxDescriptorSet`* and `maxPerStageDescriptor`*, the full value of `descriptorCount` is counted , except for descriptor bindings with a descriptor type of `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` where `descriptorCount` specifies the upper bound on the byte size of the binding, thus it counts against the `maxInlineUniformBlockSize` limit instead. .

| Note Note that while `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT` and `VK_DESCRIPTOR_BINDING_UPDATE_UNUSED_WHILE_PENDING_BIT` both involve updates to descriptor sets after they are bound, `VK_DESCRIPTOR_BINDING_UPDATE_UNUSED_WHILE_PENDING_BIT` is a weaker requirement since it is only about descriptors that are not used, whereas `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT` requires the implementation to observe updates to descriptors that are used.

    typedef VkFlags VkDescriptorBindingFlags;

or the equivalent

    typedef VkDescriptorBindingFlags VkDescriptorBindingFlagsEXT;

`VkDescriptorBindingFlags` is a bitmask type for setting a mask of zero or more VkDescriptorBindingFlagBits.

To query information about whether a descriptor set layout can be created, call:

    void vkGetDescriptorSetLayoutSupport(
        VkDevice                                    device,
        const VkDescriptorSetLayoutCreateInfo*      pCreateInfo,
        VkDescriptorSetLayoutSupport*               pSupport);

or the equivalent command

    void vkGetDescriptorSetLayoutSupportKHR(
        VkDevice                                    device,
        const VkDescriptorSetLayoutCreateInfo*      pCreateInfo,
        VkDescriptorSetLayoutSupport*               pSupport);

- `device` is the logical device that would create the descriptor set layout.

- `pCreateInfo` is a pointer to a VkDescriptorSetLayoutCreateInfo structure specifying the state of the descriptor set layout object.

- `pSupport` is a pointer to a VkDescriptorSetLayoutSupport structure, in which information about support for the descriptor set layout object is returned.

Some implementations have limitations on what fits in a descriptor set which are not easily expressible in terms of existing limits like `maxDescriptorSet`*, for example if all descriptor types share a limited space in memory but each descriptor is a different size or alignment. This command returns information about whether a descriptor set satisfies this limit. If the descriptor set layout satisfies the VkPhysicalDeviceMaintenance3Properties::`maxPerSetDescriptors` limit, this command is guaranteed to return `VK_TRUE` in VkDescriptorSetLayoutSupport::`supported`. If the descriptor set layout exceeds the VkPhysicalDeviceMaintenance3Properties::`maxPerSetDescriptors` limit, whether the descriptor set layout is supported is implementation-dependent and may depend on whether the descriptor sizes and alignments cause the layout to exceed an internal limit.

This command does not consider other limits such as `maxPerStageDescriptor`*, and so a descriptor set layout that is supported according to this command must still satisfy the pipeline layout limits such as `maxPerStageDescriptor`* in order to be used in a pipeline layout.

| Note This is a `VkDevice` query rather than `VkPhysicalDevice` because the answer may depend on enabled features.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkDescriptorSetLayoutCreateInfo structure

- `pSupport` must be a valid pointer to a VkDescriptorSetLayoutSupport structure

Information about support for the descriptor set layout is returned in a `VkDescriptorSetLayoutSupport` structure:

    typedef struct VkDescriptorSetLayoutSupport {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           supported;
    } VkDescriptorSetLayoutSupport;

or the equivalent

    typedef VkDescriptorSetLayoutSupport VkDescriptorSetLayoutSupportKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `supported` specifies whether the descriptor set layout can be created.

`supported` is set to `VK_TRUE` if the descriptor set can be created, or else is set to `VK_FALSE`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_SUPPORT`

- `pNext` must be `NULL` or a pointer to a valid instance of VkDescriptorSetVariableDescriptorCountLayoutSupport

- The `sType` value of each struct in the `pNext` chain must be unique

If the `pNext` chain of a VkDescriptorSetLayoutSupport structure includes a `VkDescriptorSetVariableDescriptorCountLayoutSupport` structure, then that structure returns additional information about whether the descriptor set layout is supported.

    typedef struct VkDescriptorSetVariableDescriptorCountLayoutSupport {
        VkStructureType    sType;
        void*              pNext;
        uint32_t           maxVariableDescriptorCount;
    } VkDescriptorSetVariableDescriptorCountLayoutSupport;

or the equivalent

    typedef VkDescriptorSetVariableDescriptorCountLayoutSupport VkDescriptorSetVariableDescriptorCountLayoutSupportEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `maxVariableDescriptorCount` indicates the maximum number of descriptors supported in the highest numbered binding of the layout, if that binding is variable-sized. If the highest numbered binding of the layout has a descriptor type of `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` then `maxVariableDescriptorCount` indicates the maximum byte size supported for the binding, if that binding is variable-sized.

If the create info includes a variable-sized descriptor, then `supported` is determined assuming the requested size of the variable-sized descriptor, and `maxVariableDescriptorCount` is set to the maximum size of that descriptor that can be successfully created (which is greater than or equal to the requested size passed in). If the create info does not include a variable-sized descriptor or if the VkPhysicalDeviceDescriptorIndexingFeatures::`descriptorBindingVariableDescriptorCount` feature is not enabled, then `maxVariableDescriptorCount` is set to zero. For the purposes of this command, a variable-sized descriptor binding with a `descriptorCount` of zero is treated as if the `descriptorCount` is one, and thus the binding is not ignored and the maximum descriptor count will be returned. If the layout is not supported, then the value written to `maxVariableDescriptorCount` is undefined.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DESCRIPTOR_SET_VARIABLE_DESCRIPTOR_COUNT_LAYOUT_SUPPORT`

The following examples show a shader snippet using two descriptor sets, and application code that creates corresponding descriptor set layouts.

GLSL example

    //
    // binding to a single sampled image descriptor in set 0
    //
    layout (set=0, binding=0) uniform texture2D mySampledImage;

    //
    // binding to an array of sampled image descriptors in set 0
    //
    layout (set=0, binding=1) uniform texture2D myArrayOfSampledImages[12];

    //
    // binding to a single uniform buffer descriptor in set 1
    //
    layout (set=1, binding=0) uniform myUniformBuffer
    {
        vec4 myElement[32];
    };

SPIR-V example

                   ...
              %1 = OpExtInstImport "GLSL.std.450"
                   ...
                   OpName %9 "mySampledImage"
                   OpName %14 "myArrayOfSampledImages"
                   OpName %18 "myUniformBuffer"
                   OpMemberName %18 0 "myElement"
                   OpName %20 ""
                   OpDecorate %9 DescriptorSet 0
                   OpDecorate %9 Binding 0
                   OpDecorate %14 DescriptorSet 0
                   OpDecorate %14 Binding 1
                   OpDecorate %17 ArrayStride 16
                   OpMemberDecorate %18 0 Offset 0
                   OpDecorate %18 Block
                   OpDecorate %20 DescriptorSet 1
                   OpDecorate %20 Binding 0
              %2 = OpTypeVoid
              %3 = OpTypeFunction %2
              %6 = OpTypeFloat 32
              %7 = OpTypeImage %6 2D 0 0 0 1 Unknown
              %8 = OpTypePointer UniformConstant %7
              %9 = OpVariable %8 UniformConstant
             %10 = OpTypeInt 32 0
             %11 = OpConstant %10 12
             %12 = OpTypeArray %7 %11
             %13 = OpTypePointer UniformConstant %12
             %14 = OpVariable %13 UniformConstant
             %15 = OpTypeVector %6 4
             %16 = OpConstant %10 32
             %17 = OpTypeArray %15 %16
             %18 = OpTypeStruct %17
             %19 = OpTypePointer Uniform %18
             %20 = OpVariable %19 Uniform
                   ...

API example

    VkResult myResult;

    const VkDescriptorSetLayoutBinding myDescriptorSetLayoutBinding[] =
    {
        // binding to a single image descriptor
        {
            0,                                      // binding
            VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE,       // descriptorType
            1,                                      // descriptorCount
            VK_SHADER_STAGE_FRAGMENT_BIT,           // stageFlags
            NULL                                    // pImmutableSamplers
        },

        // binding to an array of image descriptors
        {
            1,                                      // binding
            VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE,       // descriptorType
            12,                                     // descriptorCount
            VK_SHADER_STAGE_FRAGMENT_BIT,           // stageFlags
            NULL                                    // pImmutableSamplers
        },

        // binding to a single uniform buffer descriptor
        {
            0,                                      // binding
            VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER,      // descriptorType
            1,                                      // descriptorCount
            VK_SHADER_STAGE_FRAGMENT_BIT,           // stageFlags
            NULL                                    // pImmutableSamplers
        }
    };

    const VkDescriptorSetLayoutCreateInfo myDescriptorSetLayoutCreateInfo[] =
    {
        // Create info for first descriptor set with two descriptor bindings
        {
            VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO,    // sType
            NULL,                                                   // pNext
            0,                                                      // flags
            2,                                                      // bindingCount
            &myDescriptorSetLayoutBinding[0]                        // pBindings
        },

        // Create info for second descriptor set with one descriptor binding
        {
            VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO,    // sType
            NULL,                                                   // pNext
            0,                                                      // flags
            1,                                                      // bindingCount
            &myDescriptorSetLayoutBinding[2]                        // pBindings
        }
    };

    VkDescriptorSetLayout myDescriptorSetLayout[2];

    //
    // Create first descriptor set layout
    //
    myResult = vkCreateDescriptorSetLayout(
        myDevice,
        &myDescriptorSetLayoutCreateInfo[0],
        NULL,
        &myDescriptorSetLayout[0]);

    //
    // Create second descriptor set layout
    //
    myResult = vkCreateDescriptorSetLayout(
        myDevice,
        &myDescriptorSetLayoutCreateInfo[1],
        NULL,
        &myDescriptorSetLayout[1]);

To destroy a descriptor set layout, call:

    void vkDestroyDescriptorSetLayout(
        VkDevice                                    device,
        VkDescriptorSetLayout                       descriptorSetLayout,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that destroys the descriptor set layout.

- `descriptorSetLayout` is the descriptor set layout to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage

- If `VkAllocationCallbacks` were provided when `descriptorSetLayout` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `descriptorSetLayout` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `descriptorSetLayout` is not VK_NULL_HANDLE, `descriptorSetLayout` must be a valid VkDescriptorSetLayout handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- If `descriptorSetLayout` is a valid handle, it must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `descriptorSetLayout` must be externally synchronized

#### 13.2.2. Pipeline Layouts

Access to descriptor sets from a pipeline is accomplished through a pipeline layout. Zero or more descriptor set layouts and zero or more push constant ranges are combined to form a pipeline layout object describing the complete set of resources that can be accessed by a pipeline. The pipeline layout represents a sequence of descriptor sets with each having a specific layout. This sequence of layouts is used to determine the interface between shader stages and shader resources. Each pipeline is created using a pipeline layout.

Pipeline layout objects are represented by `VkPipelineLayout` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkPipelineLayout)

To create a pipeline layout, call:

    VkResult vkCreatePipelineLayout(
        VkDevice                                    device,
        const VkPipelineLayoutCreateInfo*           pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkPipelineLayout*                           pPipelineLayout);

- `device` is the logical device that creates the pipeline layout.

- `pCreateInfo` is a pointer to a VkPipelineLayoutCreateInfo structure specifying the state of the pipeline layout object.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pPipelineLayout` is a pointer to a VkPipelineLayout handle in which the resulting pipeline layout object is returned.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkPipelineLayoutCreateInfo structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pPipelineLayout` must be a valid pointer to a VkPipelineLayout handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The VkPipelineLayoutCreateInfo structure is defined as:

    typedef struct VkPipelineLayoutCreateInfo {
        VkStructureType                 sType;
        const void*                     pNext;
        VkPipelineLayoutCreateFlags     flags;
        uint32_t                        setLayoutCount;
        const VkDescriptorSetLayout*    pSetLayouts;
        uint32_t                        pushConstantRangeCount;
        const VkPushConstantRange*      pPushConstantRanges;
    } VkPipelineLayoutCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `setLayoutCount` is the number of descriptor sets included in the pipeline layout.

- `pSetLayouts` is a pointer to an array of `VkDescriptorSetLayout` objects.

- `pushConstantRangeCount` is the number of push constant ranges included in the pipeline layout.

- `pPushConstantRanges` is a pointer to an array of `VkPushConstantRange` structures defining a set of push constant ranges for use in a single pipeline layout. In addition to descriptor set layouts, a pipeline layout also describes how many push constants can be accessed by each stage of the pipeline.

  | Note Push constants represent a high speed path to modify constant data in pipelines that is expected to outperform memory-backed resource updates.

Valid Usage

- `setLayoutCount` must be less than or equal to `VkPhysicalDeviceLimits`::`maxBoundDescriptorSets`

- The total number of descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set with a `descriptorType` of `VK_DESCRIPTOR_TYPE_SAMPLER` and `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER` accessible to any given shader stage across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceLimits`::`maxPerStageDescriptorSamplers`

- The total number of descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set with a `descriptorType` of `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER` and `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC` accessible to any given shader stage across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceLimits`::`maxPerStageDescriptorUniformBuffers`

- The total number of descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set with a `descriptorType` of `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER` and `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC` accessible to any given shader stage across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceLimits`::`maxPerStageDescriptorStorageBuffers`

- The total number of descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set with a `descriptorType` of `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE`, and `VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER` accessible to any given shader stage across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceLimits`::`maxPerStageDescriptorSampledImages`

- The total number of descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set with a `descriptorType` of `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE`, and `VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER` accessible to any given shader stage across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceLimits`::`maxPerStageDescriptorStorageImages`

- The total number of descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set with a `descriptorType` of `VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT` accessible to any given shader stage across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceLimits`::`maxPerStageDescriptorInputAttachments`

- The total number of bindings in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set with a `descriptorType` of `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` accessible to any given shader stage across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceInlineUniformBlockPropertiesEXT`::`maxPerStageDescriptorInlineUniformBlocks`

- The total number of descriptors with a `descriptorType` of `VK_DESCRIPTOR_TYPE_SAMPLER` and `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER` accessible to any given shader stage across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceDescriptorIndexingProperties`::`maxPerStageDescriptorUpdateAfterBindSamplers`

- The total number of descriptors with a `descriptorType` of `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER` and `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC` accessible to any given shader stage across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceDescriptorIndexingProperties`::`maxPerStageDescriptorUpdateAfterBindUniformBuffers`

- The total number of descriptors with a `descriptorType` of `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER` and `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC` accessible to any given shader stage across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceDescriptorIndexingProperties`::`maxPerStageDescriptorUpdateAfterBindStorageBuffers`

- The total number of descriptors with a `descriptorType` of `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE`, and `VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER` accessible to any given shader stage across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceDescriptorIndexingProperties`::`maxPerStageDescriptorUpdateAfterBindSampledImages`

- The total number of descriptors with a `descriptorType` of `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE`, and `VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER` accessible to any given shader stage across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceDescriptorIndexingProperties`::`maxPerStageDescriptorUpdateAfterBindStorageImages`

- The total number of descriptors with a `descriptorType` of `VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT` accessible to any given shader stage across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceDescriptorIndexingProperties`::`maxPerStageDescriptorUpdateAfterBindInputAttachments`

- The total number of bindings with a `descriptorType` of `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` accessible to any given shader stage across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceInlineUniformBlockPropertiesEXT`::`maxPerStageDescriptorUpdateAfterBindInlineUniformBlocks`

- The total number of descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set with a `descriptorType` of `VK_DESCRIPTOR_TYPE_SAMPLER` and `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER` accessible across all shader stages and across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceLimits`::`maxDescriptorSetSamplers`

- The total number of descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set with a `descriptorType` of `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER` accessible across all shader stages and across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceLimits`::`maxDescriptorSetUniformBuffers`

- The total number of descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set with a `descriptorType` of `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC` accessible across all shader stages and across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceLimits`::`maxDescriptorSetUniformBuffersDynamic`

- The total number of descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set with a `descriptorType` of `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER` accessible across all shader stages and across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceLimits`::`maxDescriptorSetStorageBuffers`

- The total number of descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set with a `descriptorType` of `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC` accessible across all shader stages and across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceLimits`::`maxDescriptorSetStorageBuffersDynamic`

- The total number of descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set with a `descriptorType` of `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE`, and `VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER` accessible across all shader stages and across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceLimits`::`maxDescriptorSetSampledImages`

- The total number of descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set with a `descriptorType` of `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE`, and `VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER` accessible across all shader stages and across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceLimits`::`maxDescriptorSetStorageImages`

- The total number of descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set with a `descriptorType` of `VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT` accessible across all shader stages and across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceLimits`::`maxDescriptorSetInputAttachments`

- The total number of bindings in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set with a `descriptorType` of `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` accessible across all shader stages and across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceInlineUniformBlockPropertiesEXT`::`maxDescriptorSetInlineUniformBlocks`

- The total number of descriptors of the type `VK_DESCRIPTOR_TYPE_SAMPLER` and `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER` accessible across all shader stages and across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceDescriptorIndexingProperties`::`maxDescriptorSetUpdateAfterBindSamplers`

- The total number of descriptors of the type `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER` accessible across all shader stages and across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceDescriptorIndexingProperties`::`maxDescriptorSetUpdateAfterBindUniformBuffers`

- The total number of descriptors of the type `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC` accessible across all shader stages and across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceDescriptorIndexingProperties`::`maxDescriptorSetUpdateAfterBindUniformBuffersDynamic`

- The total number of descriptors of the type `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER` accessible across all shader stages and across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceDescriptorIndexingProperties`::`maxDescriptorSetUpdateAfterBindStorageBuffers`

- The total number of descriptors of the type `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC` accessible across all shader stages and across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceDescriptorIndexingProperties`::`maxDescriptorSetUpdateAfterBindStorageBuffersDynamic`

- The total number of descriptors of the type `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE`, and `VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER` accessible across all shader stages and across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceDescriptorIndexingProperties`::`maxDescriptorSetUpdateAfterBindSampledImages`

- The total number of descriptors of the type `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE`, and `VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER` accessible across all shader stages and across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceDescriptorIndexingProperties`::`maxDescriptorSetUpdateAfterBindStorageImages`

- The total number of descriptors of the type `VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT` accessible across all shader stages and across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceDescriptorIndexingProperties`::`maxDescriptorSetUpdateAfterBindInputAttachments`

- The total number of bindings with a `descriptorType` of `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` accessible across all shader stages and across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceInlineUniformBlockPropertiesEXT`::`maxDescriptorSetUpdateAfterBindInlineUniformBlocks`

- Any two elements of `pPushConstantRanges` must not include the same stage in `stageFlags`

- `pSetLayouts` must not contain more than one descriptor set layout that was created with `VK_DESCRIPTOR_SET_LAYOUT_CREATE_PUSH_DESCRIPTOR_BIT_KHR` set

- The total number of bindings with a `descriptorType` of `VK_DESCRIPTOR_TYPE_ACCELERATION_STRUCTURE_KHR` accessible across all shader stages and across all elements of `pSetLayouts` must be less than or equal to `VkPhysicalDeviceRayTracingPropertiesKHR`::`maxDescriptorSetAccelerationStructures`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO`

- `pNext` must be `NULL`

- `flags` must be `0`

- If `setLayoutCount` is not `0`, `pSetLayouts` must be a valid pointer to an array of `setLayoutCount` valid VkDescriptorSetLayout handles

- If `pushConstantRangeCount` is not `0`, `pPushConstantRanges` must be a valid pointer to an array of `pushConstantRangeCount` valid VkPushConstantRange structures

    typedef VkFlags VkPipelineLayoutCreateFlags;

`VkPipelineLayoutCreateFlags` is a bitmask type for setting a mask, but is currently reserved for future use.

The `VkPushConstantRange` structure is defined as:

    typedef struct VkPushConstantRange {
        VkShaderStageFlags    stageFlags;
        uint32_t              offset;
        uint32_t              size;
    } VkPushConstantRange;

- `stageFlags` is a set of stage flags describing the shader stages that will access a range of push constants. If a particular stage is not included in the range, then accessing members of that range of push constants from the corresponding shader stage will return undefined values.

- `offset` and `size` are the start offset and size, respectively, consumed by the range. Both `offset` and `size` are in units of bytes and must be a multiple of 4. The layout of the push constant variables is specified in the shader.

Valid Usage

- `offset` must be less than `VkPhysicalDeviceLimits`::`maxPushConstantsSize`

- `offset` must be a multiple of `4`

- `size` must be greater than `0`

- `size` must be a multiple of `4`

- `size` must be less than or equal to `VkPhysicalDeviceLimits`::`maxPushConstantsSize` minus `offset`

Valid Usage (Implicit)

- `stageFlags` must be a valid combination of VkShaderStageFlagBits values

- `stageFlags` must not be `0`

Once created, pipeline layouts are used as part of pipeline creation (see Pipelines), as part of binding descriptor sets (see Descriptor Set Binding), and as part of setting push constants (see Push Constant Updates). Pipeline creation accepts a pipeline layout as input, and the layout may be used to map (set, binding, arrayElement) tuples to implementation resources or memory locations within a descriptor set. The assignment of implementation resources depends only on the bindings defined in the descriptor sets that comprise the pipeline layout, and not on any shader source.

All resource variables statically used in all shaders in a pipeline must be declared with a (set,binding,arrayElement) that exists in the corresponding descriptor set layout and is of an appropriate descriptor type and includes the set of shader stages it is used by in `stageFlags`. The pipeline layout can include entries that are not used by a particular pipeline, or that are dead-code eliminated from any of the shaders. The pipeline layout allows the application to provide a consistent set of bindings across multiple pipeline compiles, which enables those pipelines to be compiled in a way that the implementation may cheaply switch pipelines without reprogramming the bindings.

Similarly, the push constant block declared in each shader (if present) must only place variables at offsets that are each included in a push constant range with `stageFlags` including the bit corresponding to the shader stage that uses it. The pipeline layout can include ranges or portions of ranges that are not used by a particular pipeline, or for which the variables have been dead-code eliminated from any of the shaders.

There is a limit on the total number of resources of each type that can be included in bindings in all descriptor set layouts in a pipeline layout as shown in Pipeline Layout Resource Limits. The “Total Resources Available” column gives the limit on the number of each type of resource that can be included in bindings in all descriptor sets in the pipeline layout. Some resource types count against multiple limits. Additionally, there are limits on the total number of each type of resource that can be used in any pipeline stage as described in Shader Resource Limits.

Table 17. Pipeline Layout Resource Limits
Total Resources Available | Resource Types
--- | ---
`maxDescriptorSetSamplers` or `maxDescriptorSetUpdateAfterBindSamplers` | sampler
combined image sampler
`maxDescriptorSetSampledImages` or `maxDescriptorSetUpdateAfterBindSampledImages` | sampled image
combined image sampler
uniform texel buffer
`maxDescriptorSetStorageImages` or `maxDescriptorSetUpdateAfterBindStorageImages` | storage image
storage texel buffer
`maxDescriptorSetUniformBuffers` or `maxDescriptorSetUpdateAfterBindUniformBuffers` | uniform buffer
uniform buffer dynamic
`maxDescriptorSetUniformBuffersDynamic` or `maxDescriptorSetUpdateAfterBindUniformBuffersDynamic` | uniform buffer dynamic
`maxDescriptorSetStorageBuffers` or `maxDescriptorSetUpdateAfterBindStorageBuffers` | storage buffer
storage buffer dynamic
`maxDescriptorSetStorageBuffersDynamic` or `maxDescriptorSetUpdateAfterBindStorageBuffersDynamic` | storage buffer dynamic
`maxDescriptorSetInputAttachments` or `maxDescriptorSetUpdateAfterBindInputAttachments` | input attachment
`maxDescriptorSetInlineUniformBlocks` or `maxDescriptorSetUpdateAfterBindInlineUniformBlocks` | inline uniform block
`maxDescriptorSetAccelerationStructures` | acceleration structure

To destroy a pipeline layout, call:

    void vkDestroyPipelineLayout(
        VkDevice                                    device,
        VkPipelineLayout                            pipelineLayout,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that destroys the pipeline layout.

- `pipelineLayout` is the pipeline layout to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage

- If `VkAllocationCallbacks` were provided when `pipelineLayout` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `pipelineLayout` was created, `pAllocator` must be `NULL`

- `pipelineLayout` must not have been passed to any `vkCmd*` command for any command buffers that are still in the recording state when `vkDestroyPipelineLayout` is called

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `pipelineLayout` is not VK_NULL_HANDLE, `pipelineLayout` must be a valid VkPipelineLayout handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- If `pipelineLayout` is a valid handle, it must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `pipelineLayout` must be externally synchronized

##### Pipeline Layout Compatibility

Two pipeline layouts are defined to be “compatible for push constants” if they were created with identical push constant ranges. Two pipeline layouts are defined to be “compatible for set N” if they were created with identically defined descriptor set layouts for sets zero through N, and if they were created with identical push constant ranges.

When binding a descriptor set (see Descriptor Set Binding) to set number N, if the previously bound descriptor sets for sets zero through N-1 were all bound using compatible pipeline layouts, then performing this binding does not disturb any of the lower numbered sets. If, additionally, the previous bound descriptor set for set N was bound using a pipeline layout compatible for set N, then the bindings in sets numbered greater than N are also not disturbed.

Similarly, when binding a pipeline, the pipeline can correctly access any previously bound descriptor sets which were bound with compatible pipeline layouts, as long as all lower numbered sets were also bound with compatible layouts.

Layout compatibility means that descriptor sets can be bound to a command buffer for use by any pipeline created with a compatible pipeline layout, and without having bound a particular pipeline first. It also means that descriptor sets can remain valid across a pipeline change, and the same resources will be accessible to the newly bound pipeline.

Implementor’s Note

A consequence of layout compatibility is that when the implementation compiles a pipeline layout and maps pipeline resources to implementation resources, the mechanism for set N should only be a function of sets [0..N].

| Note Place the least frequently changing descriptor sets near the start of the pipeline layout, and place the descriptor sets representing the most frequently changing resources near the end. When pipelines are switched, only the descriptor set bindings that have been invalidated will need to be updated and the remainder of the descriptor set bindings will remain in place.

The maximum number of descriptor sets that can be bound to a pipeline layout is queried from physical device properties (see `maxBoundDescriptorSets` in Limits).

API example

    const VkDescriptorSetLayout layouts[] = { layout1, layout2 };

    const VkPushConstantRange ranges[] =
    {
        {
            VK_PIPELINE_STAGE_VERTEX_SHADER_BIT,    // stageFlags
            0,                                      // offset
            4                                       // size
        },

        {
            VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT,  // stageFlags
            4,                                      // offset
            4                                       // size
        },
    };

    const VkPipelineLayoutCreateInfo createInfo =
    {
        VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO,  // sType
        NULL,                                           // pNext
        0,                                              // flags
        2,                                              // setLayoutCount
        layouts,                                        // pSetLayouts
        2,                                              // pushConstantRangeCount
        ranges                                          // pPushConstantRanges
    };

    VkPipelineLayout myPipelineLayout;
    myResult = vkCreatePipelineLayout(
        myDevice,
        &createInfo,
        NULL,
        &myPipelineLayout);

#### 13.2.3. Allocation of Descriptor Sets

A descriptor pool maintains a pool of descriptors, from which descriptor sets are allocated. Descriptor pools are externally synchronized, meaning that the application must not allocate and/or free descriptor sets from the same pool in multiple threads simultaneously.

Descriptor pools are represented by `VkDescriptorPool` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkDescriptorPool)

To create a descriptor pool object, call:

    VkResult vkCreateDescriptorPool(
        VkDevice                                    device,
        const VkDescriptorPoolCreateInfo*           pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkDescriptorPool*                           pDescriptorPool);

- `device` is the logical device that creates the descriptor pool.

- `pCreateInfo` is a pointer to a VkDescriptorPoolCreateInfo structure specifying the state of the descriptor pool object.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pDescriptorPool` is a pointer to a VkDescriptorPool handle in which the resulting descriptor pool object is returned.

`pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

The created descriptor pool is returned in `pDescriptorPool`.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkDescriptorPoolCreateInfo structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pDescriptorPool` must be a valid pointer to a VkDescriptorPool handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_FRAGMENTATION_EXT`

Additional information about the pool is passed in a `VkDescriptorPoolCreateInfo` structure:

    typedef struct VkDescriptorPoolCreateInfo {
        VkStructureType                sType;
        const void*                    pNext;
        VkDescriptorPoolCreateFlags    flags;
        uint32_t                       maxSets;
        uint32_t                       poolSizeCount;
        const VkDescriptorPoolSize*    pPoolSizes;
    } VkDescriptorPoolCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkDescriptorPoolCreateFlagBits specifying certain supported operations on the pool.

- `maxSets` is the maximum number of descriptor sets that can be allocated from the pool.

- `poolSizeCount` is the number of elements in `pPoolSizes`.

- `pPoolSizes` is a pointer to an array of VkDescriptorPoolSize structures, each containing a descriptor type and number of descriptors of that type to be allocated in the pool.

If multiple `VkDescriptorPoolSize` structures appear in the `pPoolSizes` array then the pool will be created with enough storage for the total number of descriptors of each type.

Fragmentation of a descriptor pool is possible and may lead to descriptor set allocation failures. A failure due to fragmentation is defined as failing a descriptor set allocation despite the sum of all outstanding descriptor set allocations from the pool plus the requested allocation requiring no more than the total number of descriptors requested at pool creation. Implementations provide certain guarantees of when fragmentation must not cause allocation failure, as described below.

If a descriptor pool has not had any descriptor sets freed since it was created or most recently reset then fragmentation must not cause an allocation failure (note that this is always the case for a pool created without the `VK_DESCRIPTOR_POOL_CREATE_FREE_DESCRIPTOR_SET_BIT` bit set). Additionally, if all sets allocated from the pool since it was created or most recently reset use the same number of descriptors (of each type) and the requested allocation also uses that same number of descriptors (of each type), then fragmentation must not cause an allocation failure.

If an allocation failure occurs due to fragmentation, an application can create an additional descriptor pool to perform further descriptor set allocations.

If `flags` has the `VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT` bit set, descriptor pool creation may fail with the error `VK_ERROR_FRAGMENTATION` if the total number of descriptors across all pools (including this one) created with this bit set exceeds `maxUpdateAfterBindDescriptorsInAllPools`, or if fragmentation of the underlying hardware resources occurs.

Valid Usage

- `maxSets` must be greater than `0`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO`

- `pNext` must be `NULL` or a pointer to a valid instance of VkDescriptorPoolInlineUniformBlockCreateInfoEXT

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be a valid combination of VkDescriptorPoolCreateFlagBits values

- `pPoolSizes` must be a valid pointer to an array of `poolSizeCount` valid VkDescriptorPoolSize structures

- `poolSizeCount` must be greater than `0`

In order to be able to allocate descriptor sets having inline uniform block bindings the descriptor pool must be created with specifying the inline uniform block binding capacity of the descriptor pool, in addition to the total inline uniform data capacity in bytes which is specified through a VkDescriptorPoolSize structure with a `descriptorType` value of `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT`. This can be done by adding a `VkDescriptorPoolInlineUniformBlockCreateInfoEXT` structure to the `pNext` chain of `VkDescriptorPoolCreateInfo`.

The `VkDescriptorPoolInlineUniformBlockCreateInfoEXT` structure is defined as:

    typedef struct VkDescriptorPoolInlineUniformBlockCreateInfoEXT {
        VkStructureType    sType;
        const void*        pNext;
        uint32_t           maxInlineUniformBlockBindings;
    } VkDescriptorPoolInlineUniformBlockCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `maxInlineUniformBlockBindings` is the number of inline uniform block bindings to allocate.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_INLINE_UNIFORM_BLOCK_CREATE_INFO_EXT`

Bits which can be set in VkDescriptorPoolCreateInfo::`flags` to enable operations on a descriptor pool are:

    typedef enum VkDescriptorPoolCreateFlagBits {
        VK_DESCRIPTOR_POOL_CREATE_FREE_DESCRIPTOR_SET_BIT = 0x00000001,
        VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT = 0x00000002,
        VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT_EXT = VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT,
        VK_DESCRIPTOR_POOL_CREATE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkDescriptorPoolCreateFlagBits;

- `VK_DESCRIPTOR_POOL_CREATE_FREE_DESCRIPTOR_SET_BIT` specifies that descriptor sets can return their individual allocations to the pool, i.e. all of vkAllocateDescriptorSets, vkFreeDescriptorSets, and vkResetDescriptorPool are allowed. Otherwise, descriptor sets allocated from the pool must not be individually freed back to the pool, i.e. only vkAllocateDescriptorSets and vkResetDescriptorPool are allowed.

- `VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT` specifies that descriptor sets allocated from this pool can include bindings with the `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT` bit set. It is valid to allocate descriptor sets that have bindings that do not set the `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT` bit from a pool that has `VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT` set.

    typedef VkFlags VkDescriptorPoolCreateFlags;

`VkDescriptorPoolCreateFlags` is a bitmask type for setting a mask of zero or more VkDescriptorPoolCreateFlagBits.

The `VkDescriptorPoolSize` structure is defined as:

    typedef struct VkDescriptorPoolSize {
        VkDescriptorType    type;
        uint32_t            descriptorCount;
    } VkDescriptorPoolSize;

- `type` is the type of descriptor.

- `descriptorCount` is the number of descriptors of that type to allocate. If `type` is `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` then `descriptorCount` is the number of bytes to allocate for descriptors of this type.

| Note When creating a descriptor pool that will contain descriptors for combined image samplers of multi-planar formats, an application needs to account for non-trivial descriptor consumption when choosing the `descriptorCount` value, as indicated by VkSamplerYcbcrConversionImageFormatProperties::`combinedImageSamplerDescriptorCount`.

Valid Usage

- `descriptorCount` must be greater than `0`

- If `type` is `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` then `descriptorCount` must be a multiple of `4`

Valid Usage (Implicit)

- `type` must be a valid VkDescriptorType value

To destroy a descriptor pool, call:

    void vkDestroyDescriptorPool(
        VkDevice                                    device,
        VkDescriptorPool                            descriptorPool,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that destroys the descriptor pool.

- `descriptorPool` is the descriptor pool to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

When a pool is destroyed, all descriptor sets allocated from the pool are implicitly freed and become invalid. Descriptor sets allocated from a given pool do not need to be freed before destroying that descriptor pool.

Valid Usage

- All submitted commands that refer to `descriptorPool` (via any allocated descriptor sets) must have completed execution

- If `VkAllocationCallbacks` were provided when `descriptorPool` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `descriptorPool` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `descriptorPool` is not VK_NULL_HANDLE, `descriptorPool` must be a valid VkDescriptorPool handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- If `descriptorPool` is a valid handle, it must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `descriptorPool` must be externally synchronized

Descriptor sets are allocated from descriptor pool objects, and are represented by `VkDescriptorSet` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkDescriptorSet)

To allocate descriptor sets from a descriptor pool, call:

    VkResult vkAllocateDescriptorSets(
        VkDevice                                    device,
        const VkDescriptorSetAllocateInfo*          pAllocateInfo,
        VkDescriptorSet*                            pDescriptorSets);

- `device` is the logical device that owns the descriptor pool.

- `pAllocateInfo` is a pointer to a VkDescriptorSetAllocateInfo structure describing parameters of the allocation.

- `pDescriptorSets` is a pointer to an array of VkDescriptorSet handles in which the resulting descriptor set objects are returned.

The allocated descriptor sets are returned in `pDescriptorSets`.

When a descriptor set is allocated, the initial state is largely uninitialized and all descriptors are undefined. Descriptors also become undefined if the underlying resource is destroyed. Descriptor sets containing undefined descriptors can still be bound and used, subject to the following conditions:

- For descriptor set bindings created with the `VK_DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT` bit set, all descriptors in that binding that are dynamically used must have been populated before the descriptor set is consumed.

- For descriptor set bindings created without the `VK_DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT` bit set, all descriptors in that binding that are statically used must have been populated before the descriptor set is consumed.

- Descriptor bindings with descriptor type of `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` can be undefined when the descriptor set is consumed; though values in that block will be undefined.

- Entries that are not used by a pipeline can have undefined descriptors.

If a call to `vkAllocateDescriptorSets` would cause the total number of descriptor sets allocated from the pool to exceed the value of VkDescriptorPoolCreateInfo::`maxSets` used to create `pAllocateInfo->descriptorPool`, then the allocation may fail due to lack of space in the descriptor pool. Similarly, the allocation may fail due to lack of space if the call to `vkAllocateDescriptorSets` would cause the number of any given descriptor type to exceed the sum of all the `descriptorCount` members of each element of VkDescriptorPoolCreateInfo::`pPoolSizes` with a `member` equal to that type.

Additionally, the allocation may also fail if a call to `vkAllocateDescriptorSets` would cause the total number of inline uniform block bindings allocated from the pool to exceed the value of VkDescriptorPoolInlineUniformBlockCreateInfoEXT::`maxInlineUniformBlockBindings` used to create the descriptor pool.

If the allocation fails due to no more space in the descriptor pool, and not because of system or device memory exhaustion, then `VK_ERROR_OUT_OF_POOL_MEMORY` must be returned.

`vkAllocateDescriptorSets` can be used to create multiple descriptor sets. If the creation of any of those descriptor sets fails, then the implementation must destroy all successfully created descriptor set objects from this command, set all entries of the `pDescriptorSets` array to VK_NULL_HANDLE and return the error.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pAllocateInfo` must be a valid pointer to a valid VkDescriptorSetAllocateInfo structure

- `pDescriptorSets` must be a valid pointer to an array of `pAllocateInfo`::descriptorSetCount VkDescriptorSet handles

- The value referenced by `pAllocateInfo`::`descriptorSetCount` must be greater than `0`

Host Synchronization

- Host access to `pAllocateInfo`::descriptorPool must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_FRAGMENTED_POOL`

  - `VK_ERROR_OUT_OF_POOL_MEMORY`

The `VkDescriptorSetAllocateInfo` structure is defined as:

    typedef struct VkDescriptorSetAllocateInfo {
        VkStructureType                 sType;
        const void*                     pNext;
        VkDescriptorPool                descriptorPool;
        uint32_t                        descriptorSetCount;
        const VkDescriptorSetLayout*    pSetLayouts;
    } VkDescriptorSetAllocateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `descriptorPool` is the pool which the sets will be allocated from.

- `descriptorSetCount` determines the number of descriptor sets to be allocated from the pool.

- `pSetLayouts` is a pointer to an array of descriptor set layouts, with each member specifying how the corresponding descriptor set is allocated.

Valid Usage

- Each element of `pSetLayouts` must not have been created with `VK_DESCRIPTOR_SET_LAYOUT_CREATE_PUSH_DESCRIPTOR_BIT_KHR` set

- If any element of `pSetLayouts` was created with the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set, `descriptorPool` must have been created with the `VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT` flag set

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO`

- `pNext` must be `NULL` or a pointer to a valid instance of VkDescriptorSetVariableDescriptorCountAllocateInfo

- The `sType` value of each struct in the `pNext` chain must be unique

- `descriptorPool` must be a valid VkDescriptorPool handle

- `pSetLayouts` must be a valid pointer to an array of `descriptorSetCount` valid VkDescriptorSetLayout handles

- `descriptorSetCount` must be greater than `0`

- Both of `descriptorPool`, and the elements of `pSetLayouts` must have been created, allocated, or retrieved from the same VkDevice

If the `pNext` chain of a VkDescriptorSetAllocateInfo structure includes a `VkDescriptorSetVariableDescriptorCountAllocateInfo` structure, then that structure includes an array of descriptor counts for variable descriptor count bindings, one for each descriptor set being allocated.

The `VkDescriptorSetVariableDescriptorCountAllocateInfo` structure is defined as:

    typedef struct VkDescriptorSetVariableDescriptorCountAllocateInfo {
        VkStructureType    sType;
        const void*        pNext;
        uint32_t           descriptorSetCount;
        const uint32_t*    pDescriptorCounts;
    } VkDescriptorSetVariableDescriptorCountAllocateInfo;

or the equivalent

    typedef VkDescriptorSetVariableDescriptorCountAllocateInfo VkDescriptorSetVariableDescriptorCountAllocateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `descriptorSetCount` is zero or the number of elements in `pDescriptorCounts`.

- `pDescriptorCounts` is a pointer to an array of descriptor counts, with each member specifying the number of descriptors in a variable descriptor count binding in the corresponding descriptor set being allocated.

If `descriptorSetCount` is zero or this structure is not included in the `pNext` chain, then the variable lengths are considered to be zero. Otherwise, `pDescriptorCounts`[i] is the number of descriptors in the variable count descriptor binding in the corresponding descriptor set layout. If the variable count descriptor binding in the corresponding descriptor set layout has a descriptor type of `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` then `pDescriptorCounts`[i] specifies the binding’s capacity in bytes. If VkDescriptorSetAllocateInfo::`pSetLayouts`[i] does not include a variable count descriptor binding, then `pDescriptorCounts`[i] is ignored.

Valid Usage

- If `descriptorSetCount` is not zero, `descriptorSetCount` must equal VkDescriptorSetAllocateInfo::`descriptorSetCount`

- If VkDescriptorSetAllocateInfo::`pSetLayouts`[i] has a variable descriptor count binding, then `pDescriptorCounts`[i] must be less than or equal to the descriptor count specified for that binding when the descriptor set layout was created.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DESCRIPTOR_SET_VARIABLE_DESCRIPTOR_COUNT_ALLOCATE_INFO`

- If `descriptorSetCount` is not `0`, `pDescriptorCounts` must be a valid pointer to an array of `descriptorSetCount` `uint32_t` values

To free allocated descriptor sets, call:

    VkResult vkFreeDescriptorSets(
        VkDevice                                    device,
        VkDescriptorPool                            descriptorPool,
        uint32_t                                    descriptorSetCount,
        const VkDescriptorSet*                      pDescriptorSets);

- `device` is the logical device that owns the descriptor pool.

- `descriptorPool` is the descriptor pool from which the descriptor sets were allocated.

- `descriptorSetCount` is the number of elements in the `pDescriptorSets` array.

- `pDescriptorSets` is a pointer to an array of handles to VkDescriptorSet objects.

After calling `vkFreeDescriptorSets`, all descriptor sets in `pDescriptorSets` are invalid.

Valid Usage

- All submitted commands that refer to any element of `pDescriptorSets` must have completed execution

- `pDescriptorSets` must be a valid pointer to an array of `descriptorSetCount` `VkDescriptorSet` handles, each element of which must either be a valid handle or VK_NULL_HANDLE

- Each valid handle in `pDescriptorSets` must have been allocated from `descriptorPool`

- `descriptorPool` must have been created with the `VK_DESCRIPTOR_POOL_CREATE_FREE_DESCRIPTOR_SET_BIT` flag

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `descriptorPool` must be a valid VkDescriptorPool handle

- `descriptorSetCount` must be greater than `0`

- `descriptorPool` must have been created, allocated, or retrieved from `device`

- Each element of `pDescriptorSets` that is a valid handle must have been created, allocated, or retrieved from `descriptorPool`

Host Synchronization

- Host access to `descriptorPool` must be externally synchronized

- Host access to each member of `pDescriptorSets` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

To return all descriptor sets allocated from a given pool to the pool, rather than freeing individual descriptor sets, call:

    VkResult vkResetDescriptorPool(
        VkDevice                                    device,
        VkDescriptorPool                            descriptorPool,
        VkDescriptorPoolResetFlags                  flags);

- `device` is the logical device that owns the descriptor pool.

- `descriptorPool` is the descriptor pool to be reset.

- `flags` is reserved for future use.

Resetting a descriptor pool recycles all of the resources from all of the descriptor sets allocated from the descriptor pool back to the descriptor pool, and the descriptor sets are implicitly freed.

Valid Usage

- All uses of `descriptorPool` (via any allocated descriptor sets) must have completed execution

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `descriptorPool` must be a valid VkDescriptorPool handle

- `flags` must be `0`

- `descriptorPool` must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `descriptorPool` must be externally synchronized

- Host access to any `VkDescriptorSet` objects allocated from `descriptorPool` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

    typedef VkFlags VkDescriptorPoolResetFlags;

`VkDescriptorPoolResetFlags` is a bitmask type for setting a mask, but is currently reserved for future use.

#### 13.2.4. Descriptor Set Updates

Once allocated, descriptor sets can be updated with a combination of write and copy operations. To update descriptor sets, call:

    void vkUpdateDescriptorSets(
        VkDevice                                    device,
        uint32_t                                    descriptorWriteCount,
        const VkWriteDescriptorSet*                 pDescriptorWrites,
        uint32_t                                    descriptorCopyCount,
        const VkCopyDescriptorSet*                  pDescriptorCopies);

- `device` is the logical device that updates the descriptor sets.

- `descriptorWriteCount` is the number of elements in the `pDescriptorWrites` array.

- `pDescriptorWrites` is a pointer to an array of VkWriteDescriptorSet structures describing the descriptor sets to write to.

- `descriptorCopyCount` is the number of elements in the `pDescriptorCopies` array.

- `pDescriptorCopies` is a pointer to an array of VkCopyDescriptorSet structures describing the descriptor sets to copy between.

The operations described by `pDescriptorWrites` are performed first, followed by the operations described by `pDescriptorCopies`. Within each array, the operations are performed in the order they appear in the array.

Each element in the `pDescriptorWrites` array describes an operation updating the descriptor set using descriptors for resources specified in the structure.

Each element in the `pDescriptorCopies` array is a VkCopyDescriptorSet structure describing an operation copying descriptors between sets.

If the `dstSet` member of any element of `pDescriptorWrites` or `pDescriptorCopies` is bound, accessed, or modified by any command that was recorded to a command buffer which is currently in the recording or executable state, and any of the descriptor bindings that are updated were not created with the `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT` or `VK_DESCRIPTOR_BINDING_UPDATE_UNUSED_WHILE_PENDING_BIT` bits set, that command buffer becomes invalid.

Valid Usage

- Descriptor bindings updated by this command which were created without the `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT` or `VK_DESCRIPTOR_BINDING_UPDATE_UNUSED_WHILE_PENDING_BIT` bits set must not be used by any command that was recorded to a command buffer which is in the pending state.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `descriptorWriteCount` is not `0`, `pDescriptorWrites` must be a valid pointer to an array of `descriptorWriteCount` valid VkWriteDescriptorSet structures

- If `descriptorCopyCount` is not `0`, `pDescriptorCopies` must be a valid pointer to an array of `descriptorCopyCount` valid VkCopyDescriptorSet structures

Host Synchronization

- Host access to `pDescriptorWrites`[].dstSet must be externally synchronized

- Host access to `pDescriptorCopies`[].dstSet must be externally synchronized

The `VkWriteDescriptorSet` structure is defined as:

    typedef struct VkWriteDescriptorSet {
        VkStructureType                  sType;
        const void*                      pNext;
        VkDescriptorSet                  dstSet;
        uint32_t                         dstBinding;
        uint32_t                         dstArrayElement;
        uint32_t                         descriptorCount;
        VkDescriptorType                 descriptorType;
        const VkDescriptorImageInfo*     pImageInfo;
        const VkDescriptorBufferInfo*    pBufferInfo;
        const VkBufferView*              pTexelBufferView;
    } VkWriteDescriptorSet;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `dstSet` is the destination descriptor set to update.

- `dstBinding` is the descriptor binding within that set.

- `dstArrayElement` is the starting element in that array. If the descriptor binding identified by `dstSet` and `dstBinding` has a descriptor type of `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` then `dstArrayElement` specifies the starting byte offset within the binding.

- `descriptorCount` is the number of descriptors to update (the number of elements in `pImageInfo`, `pBufferInfo`, or `pTexelBufferView` , or a value matching the `dataSize` member of a VkWriteDescriptorSetInlineUniformBlockEXT structure in the `pNext` chain , or a value matching the `accelerationStructureCount` of a VkWriteDescriptorSetAccelerationStructureKHR structure in the `pNext` chain ). If the descriptor binding identified by `dstSet` and `dstBinding` has a descriptor type of `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` then `descriptorCount` specifies the number of bytes to update.

- `descriptorType` is a VkDescriptorType specifying the type of each descriptor in `pImageInfo`, `pBufferInfo`, or `pTexelBufferView`, as described below. It must be the same type as that specified in `VkDescriptorSetLayoutBinding` for `dstSet` at `dstBinding`. The type of the descriptor also controls which array the descriptors are taken from.

- `pImageInfo` is a pointer to an array of VkDescriptorImageInfo structures or is ignored, as described below.

- `pBufferInfo` is a pointer to an array of VkDescriptorBufferInfo structures or is ignored, as described below.

- `pTexelBufferView` is a pointer to an array of VkBufferView handles as described in the Buffer Views section or is ignored, as described below.

Only one of `pImageInfo`, `pBufferInfo`, or `pTexelBufferView` members is used according to the descriptor type specified in the `descriptorType` member of the containing `VkWriteDescriptorSet` structure, or none of them in case `descriptorType` is `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT`, in which case the source data for the descriptor writes is taken from the VkWriteDescriptorSetInlineUniformBlockEXT structure included in the `pNext` chain of `VkWriteDescriptorSet`, or if `descriptorType` is `VK_DESCRIPTOR_TYPE_ACCELERATION_STRUCTURE_KHR`, in which case the source data for the descriptor writes is taken from the VkWriteDescriptorSetAccelerationStructureKHR structure in the `pNext` chain of `VkWriteDescriptorSet`, as specified below.

If the `dstBinding` has fewer than `descriptorCount` array elements remaining starting from `dstArrayElement`, then the remainder will be used to update the subsequent binding - `dstBinding`+1 starting at array element zero. If a binding has a `descriptorCount` of zero, it is skipped. This behavior applies recursively, with the update affecting consecutive bindings as needed to update all `descriptorCount` descriptors.

| Note The same behavior applies to bindings with a descriptor type of `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` where `descriptorCount` specifies the number of bytes to update while `dstArrayElement` specifies the starting byte offset, thus in this case if the `dstBinding` has a smaller byte size than the sum of `dstArrayElement` and `descriptorCount`, then the remainder will be used to update the subsequent binding - `dstBinding`+1 starting at offset zero. This falls out as a special case of the above rule.

Valid Usage

- `dstBinding` must be less than or equal to the maximum value of `binding` of all VkDescriptorSetLayoutBinding structures specified when `dstSet`’s descriptor set layout was created

- `dstBinding` must be a binding with a non-zero `descriptorCount`

- All consecutive bindings updated via a single `VkWriteDescriptorSet` structure, except those with a `descriptorCount` of zero, must have identical `descriptorType` and `stageFlags`.

- All consecutive bindings updated via a single `VkWriteDescriptorSet` structure, except those with a `descriptorCount` of zero, must all either use immutable samplers or must all not use immutable samplers.

- `descriptorType` must match the type of `dstBinding` within `dstSet`

- `dstSet` must be a valid VkDescriptorSet handle

- The sum of `dstArrayElement` and `descriptorCount` must be less than or equal to the number of array elements in the descriptor set binding specified by `dstBinding`, and all applicable consecutive bindings, as described by consecutive binding updates

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT`, `dstArrayElement` must be an integer multiple of `4`

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT`, `descriptorCount` must be an integer multiple of `4`

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_SAMPLER`, `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE`, `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE`, or `VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT`, `pImageInfo` must be a valid pointer to an array of `descriptorCount` valid `VkDescriptorImageInfo` structures

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER` or `VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER`, `pTexelBufferView` must be a valid pointer to an array of `descriptorCount` valid `VkBufferView` handles

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER`, `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER`, `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC`, or `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC`, `pBufferInfo` must be a valid pointer to an array of `descriptorCount` valid `VkDescriptorBufferInfo` structures

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_SAMPLER` or `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, and `dstSet` was not allocated with a layout that included immutable samplers for `dstBinding` with `descriptorType`, the `sampler` member of each element of `pImageInfo` must be a valid `VkSampler` object

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE`, `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE`, or `VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT`, the `imageView` and `imageLayout` members of each element of `pImageInfo` must be a valid `VkImageView` and VkImageLayout, respectively

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT`, the `pNext` chain must include a VkWriteDescriptorSetInlineUniformBlockEXT structure whose `dataSize` member equals `descriptorCount`

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_ACCELERATION_STRUCTURE_KHR`, the `pNext` chain must include a VkWriteDescriptorSetAccelerationStructureKHR structure whose `accelerationStructureCount` member equals `descriptorCount`

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE`, then the `imageView` member of each `pImageInfo` element must have been created without a `VkSamplerYcbcrConversionInfo` structure in its `pNext` chain

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, and if any element of `pImageInfo` has a `imageView` member that was created with a `VkSamplerYcbcrConversionInfo` structure in its `pNext` chain, then `dstSet` must have been allocated with a layout that included immutable samplers for `dstBinding`, and the corresponding immutable sampler must have been created with an identically defined `VkSamplerYcbcrConversionInfo` object

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, and `dstSet` was allocated with a layout that included immutable samplers for `dstBinding`, then the `imageView` member of each element of `pImageInfo` which corresponds to an immutable sampler that enables sampler Y′CBCR conversion must have been created with a `VkSamplerYcbcrConversionInfo` structure in its `pNext` chain with an identically defined `VkSamplerYcbcrConversionInfo` to the corresponding immutable sampler

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE`, for each descriptor that will be accessed via load or store operations the `imageLayout` member for corresponding elements of `pImageInfo` must be `VK_IMAGE_LAYOUT_GENERAL`

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER` or `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC`, the `offset` member of each element of `pBufferInfo` must be a multiple of `VkPhysicalDeviceLimits`::`minUniformBufferOffsetAlignment`

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER` or `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC`, the `offset` member of each element of `pBufferInfo` must be a multiple of `VkPhysicalDeviceLimits`::`minStorageBufferOffsetAlignment`

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER`, `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC`, `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER`, or `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC`, and the `buffer` member of any element of `pBufferInfo` is the handle of a non-sparse buffer, then that buffer must be bound completely and contiguously to a single `VkDeviceMemory` object

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER` or `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC`, the `buffer` member of each element of `pBufferInfo` must have been created with `VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT` set

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER` or `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC`, the `buffer` member of each element of `pBufferInfo` must have been created with `VK_BUFFER_USAGE_STORAGE_BUFFER_BIT` set

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER` or `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC`, the `range` member of each element of `pBufferInfo`, or the effective range if `range` is `VK_WHOLE_SIZE`, must be less than or equal to `VkPhysicalDeviceLimits`::`maxUniformBufferRange`

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER` or `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC`, the `range` member of each element of `pBufferInfo`, or the effective range if `range` is `VK_WHOLE_SIZE`, must be less than or equal to `VkPhysicalDeviceLimits`::`maxStorageBufferRange`

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER`, the `VkBuffer` that each element of `pTexelBufferView` was created from must have been created with `VK_BUFFER_USAGE_UNIFORM_TEXEL_BUFFER_BIT` set

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER`, the `VkBuffer` that each element of `pTexelBufferView` was created from must have been created with `VK_BUFFER_USAGE_STORAGE_TEXEL_BUFFER_BIT` set

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE` or `VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT`, the `imageView` member of each element of `pImageInfo` must have been created with the identity swizzle

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE` or `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, the `imageView` member of each element of `pImageInfo` must have been created with `VK_IMAGE_USAGE_SAMPLED_BIT` set

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE` or `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, the `imageLayout` member of each element of `pImageInfo` must be a member of the list given in Sampled Image or Combined Image Sampler, corresponding to its type

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT`, the `imageView` member of each element of `pImageInfo` must have been created with `VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT` set

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE`, the `imageView` member of each element of `pImageInfo` must have been created with `VK_IMAGE_USAGE_STORAGE_BIT` set

- All consecutive bindings updated via a single `VkWriteDescriptorSet` structure, except those with a `descriptorCount` of zero, must have identical VkDescriptorBindingFlagBits.

- If `descriptorType` is `VK_DESCRIPTOR_TYPE_SAMPLER`, then `dstSet` must not have been allocated with a layout that included immutable samplers for `dstBinding`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkWriteDescriptorSetAccelerationStructureKHR or VkWriteDescriptorSetInlineUniformBlockEXT

- The `sType` value of each struct in the `pNext` chain must be unique

- `descriptorType` must be a valid VkDescriptorType value

- `descriptorCount` must be greater than `0`

- Both of `dstSet`, and the elements of `pTexelBufferView` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

The type of descriptors in a descriptor set is specified by VkWriteDescriptorSet::`descriptorType`, which must be one of the values:

    typedef enum VkDescriptorType {
        VK_DESCRIPTOR_TYPE_SAMPLER = 0,
        VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER = 1,
        VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE = 2,
        VK_DESCRIPTOR_TYPE_STORAGE_IMAGE = 3,
        VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER = 4,
        VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER = 5,
        VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER = 6,
        VK_DESCRIPTOR_TYPE_STORAGE_BUFFER = 7,
        VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC = 8,
        VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC = 9,
        VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT = 10,
        VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT = 1000138000,
        VK_DESCRIPTOR_TYPE_ACCELERATION_STRUCTURE_KHR = 1000165000,
        VK_DESCRIPTOR_TYPE_ACCELERATION_STRUCTURE_NV = VK_DESCRIPTOR_TYPE_ACCELERATION_STRUCTURE_KHR,
        VK_DESCRIPTOR_TYPE_MAX_ENUM = 0x7FFFFFFF
    } VkDescriptorType;

- `VK_DESCRIPTOR_TYPE_SAMPLER` specifies a sampler descriptor.

- `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER` specifies a combined image sampler descriptor.

- `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE` specifies a sampled image descriptor.

- `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE` specifies a storage image descriptor.

- `VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER` specifies a uniform texel buffer descriptor.

- `VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER` specifies a storage texel buffer descriptor.

- `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER` specifies a uniform buffer descriptor.

- `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER` specifies a storage buffer descriptor.

- `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC` specifies a dynamic uniform buffer descriptor.

- `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC` specifies a dynamic storage buffer descriptor.

- `VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT` specifies an input attachment descriptor.

- `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` specifies an inline uniform block.

When a descriptor set is updated via elements of VkWriteDescriptorSet, members of `pImageInfo`, `pBufferInfo` and `pTexelBufferView` are only accessed by the implementation when they correspond to descriptor type being defined - otherwise they are ignored. The members accessed are as follows for each descriptor type:

- For `VK_DESCRIPTOR_TYPE_SAMPLER`, only the `sampler` member of each element of VkWriteDescriptorSet::`pImageInfo` is accessed.

- For `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE`, `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE`, or `VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT`, only the `imageView` and `imageLayout` members of each element of VkWriteDescriptorSet::`pImageInfo` are accessed.

- For `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, all members of each element of VkWriteDescriptorSet::`pImageInfo` are accessed.

- For `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER`, `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER`, `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC`, or `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC`, all members of each element of VkWriteDescriptorSet::`pBufferInfo` are accessed.

- For `VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER` or `VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER`, each element of VkWriteDescriptorSet::`pTexelBufferView` is accessed.

When updating descriptors with a `descriptorType` of `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT`, none of the `pImageInfo`, `pBufferInfo`, or `pTexelBufferView` members are accessed, instead the source data of the descriptor update operation is taken from the VkWriteDescriptorSetInlineUniformBlockEXT structure in the `pNext` chain of `VkWriteDescriptorSet`. When updating descriptors with a `descriptorType` of `VK_DESCRIPTOR_TYPE_ACCELERATION_STRUCTURE_KHR`, none of the `pImageInfo`, `pBufferInfo`, or `pTexelBufferView` members are accessed, instead the source data of the descriptor update operation is taken from the VkWriteDescriptorSetAccelerationStructureKHR structure in the `pNext` chain of `VkWriteDescriptorSet`.

The `VkDescriptorBufferInfo` structure is defined as:

    typedef struct VkDescriptorBufferInfo {
        VkBuffer        buffer;
        VkDeviceSize    offset;
        VkDeviceSize    range;
    } VkDescriptorBufferInfo;

- `buffer` is the buffer resource.

- `offset` is the offset in bytes from the start of `buffer`. Access to buffer memory via this descriptor uses addressing that is relative to this starting offset.

- `range` is the size in bytes that is used for this descriptor update, or `VK_WHOLE_SIZE` to use the range from `offset` to the end of the buffer.

| Note When setting `range` to `VK_WHOLE_SIZE`, the effective range must not be larger than the maximum range for the descriptor type (`maxUniformBufferRange` or `maxStorageBufferRange`). This means that `VK_WHOLE_SIZE` is not typically useful in the common case where uniform buffer descriptors are suballocated from a buffer that is much larger than `maxUniformBufferRange`.

For `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC` and `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC` descriptor types, `offset` is the base offset from which the dynamic offset is applied and `range` is the static size used for all dynamic offsets.

Valid Usage

- `offset` must be less than the size of `buffer`

- If `range` is not equal to `VK_WHOLE_SIZE`, `range` must be greater than `0`

- If `range` is not equal to `VK_WHOLE_SIZE`, `range` must be less than or equal to the size of `buffer` minus `offset`

Valid Usage (Implicit)

- `buffer` must be a valid VkBuffer handle

The `VkDescriptorImageInfo` structure is defined as:

    typedef struct VkDescriptorImageInfo {
        VkSampler        sampler;
        VkImageView      imageView;
        VkImageLayout    imageLayout;
    } VkDescriptorImageInfo;

- `sampler` is a sampler handle, and is used in descriptor updates for types `VK_DESCRIPTOR_TYPE_SAMPLER` and `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER` if the binding being updated does not use immutable samplers.

- `imageView` is an image view handle, and is used in descriptor updates for types `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE`, `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE`, `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, and `VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT`.

- `imageLayout` is the layout that the image subresources accessible from `imageView` will be in at the time this descriptor is accessed. `imageLayout` is used in descriptor updates for types `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE`, `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE`, `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, and `VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT`.

Members of `VkDescriptorImageInfo` that are not used in an update (as described above) are ignored.

Valid Usage

- `imageView` must not be 2D or 2D array image view created from a 3D image

- If `imageView` is created from a depth/stencil image, the `aspectMask` used to create the `imageView` must include either `VK_IMAGE_ASPECT_DEPTH_BIT` or `VK_IMAGE_ASPECT_STENCIL_BIT` but not both.

- `imageLayout` must match the actual VkImageLayout of each subresource accessible from `imageView` at the time this descriptor is accessed as defined by the image layout matching rules

- If `sampler` is used and the VkFormat of the image is a multi-planar format, the image must have been created with `VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT`, and the `aspectMask` of the `imageView` must be `VK_IMAGE_ASPECT_PLANE_0_BIT`, `VK_IMAGE_ASPECT_PLANE_1_BIT` or (for three-plane formats only) `VK_IMAGE_ASPECT_PLANE_2_BIT`

Valid Usage (Implicit)

- Both of `imageView`, and `sampler` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

If the `descriptorType` member of VkWriteDescriptorSet is `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` then the data to write to the descriptor set is specified through a `VkWriteDescriptorSetInlineUniformBlockEXT` structure included in the `pNext` chain of `VkWriteDescriptorSet`.

The `VkWriteDescriptorSetInlineUniformBlockEXT` structure is defined as:

    typedef struct VkWriteDescriptorSetInlineUniformBlockEXT {
        VkStructureType    sType;
        const void*        pNext;
        uint32_t           dataSize;
        const void*        pData;
    } VkWriteDescriptorSetInlineUniformBlockEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `dataSize` is the number of bytes of inline uniform block data pointed to by `pData`.

- `pData` is a pointer to `dataSize` number of bytes of data to write to the inline uniform block.

Valid Usage

- `dataSize` must be an integer multiple of `4`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET_INLINE_UNIFORM_BLOCK_EXT`

- `pData` must be a valid pointer to an array of `dataSize` bytes

- `dataSize` must be greater than `0`

The `VkWriteDescriptorSetAccelerationStructureKHR` structure is defined as:

    typedef struct VkWriteDescriptorSetAccelerationStructureKHR {
        VkStructureType                      sType;
        const void*                          pNext;
        uint32_t                             accelerationStructureCount;
        const VkAccelerationStructureKHR*    pAccelerationStructures;
    } VkWriteDescriptorSetAccelerationStructureKHR;

or the equivalent

    typedef VkWriteDescriptorSetAccelerationStructureKHR VkWriteDescriptorSetAccelerationStructureNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `accelerationStructureCount` is the number of elements in `pAccelerationStructures`.

- `pAccelerationStructures` are the acceleration structures to update.

Valid Usage

- `accelerationStructureCount` must be equal to `descriptorCount` in the extended structure

- Each acceleration structure in `pAccelerationStructures` must have been created with `VK_ACCELERATION_STRUCTURE_TYPE_TOP_LEVEL_KHR`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET_ACCELERATION_STRUCTURE_KHR`

- `pAccelerationStructures` must be a valid pointer to an array of `accelerationStructureCount` valid VkAccelerationStructureKHR handles

- `accelerationStructureCount` must be greater than `0`

The `VkCopyDescriptorSet` structure is defined as:

    typedef struct VkCopyDescriptorSet {
        VkStructureType    sType;
        const void*        pNext;
        VkDescriptorSet    srcSet;
        uint32_t           srcBinding;
        uint32_t           srcArrayElement;
        VkDescriptorSet    dstSet;
        uint32_t           dstBinding;
        uint32_t           dstArrayElement;
        uint32_t           descriptorCount;
    } VkCopyDescriptorSet;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `srcSet`, `srcBinding`, and `srcArrayElement` are the source set, binding, and array element, respectively. If the descriptor binding identified by `srcSet` and `srcBinding` has a descriptor type of `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` then `srcArrayElement` specifies the starting byte offset within the binding to copy from.

- `dstSet`, `dstBinding`, and `dstArrayElement` are the destination set, binding, and array element, respectively. If the descriptor binding identified by `dstSet` and `dstBinding` has a descriptor type of `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` then `dstArrayElement` specifies the starting byte offset within the binding to copy to.

- `descriptorCount` is the number of descriptors to copy from the source to destination. If `descriptorCount` is greater than the number of remaining array elements in the source or destination binding, those affect consecutive bindings in a manner similar to VkWriteDescriptorSet above. If the descriptor binding identified by `srcSet` and `srcBinding` has a descriptor type of `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` then `descriptorCount` specifies the number of bytes to copy and the remaining array elements in the source or destination binding refer to the remaining number of bytes in those.

Valid Usage

- `srcBinding` must be a valid binding within `srcSet`

- The sum of `srcArrayElement` and `descriptorCount` must be less than or equal to the number of array elements in the descriptor set binding specified by `srcBinding`, and all applicable consecutive bindings, as described by consecutive binding updates

- `dstBinding` must be a valid binding within `dstSet`

- The sum of `dstArrayElement` and `descriptorCount` must be less than or equal to the number of array elements in the descriptor set binding specified by `dstBinding`, and all applicable consecutive bindings, as described by consecutive binding updates

- The type of `dstBinding` within `dstSet` must be equal to the type of `srcBinding` within `srcSet`

- If `srcSet` is equal to `dstSet`, then the source and destination ranges of descriptors must not overlap, where the ranges may include array elements from consecutive bindings as described by consecutive binding updates

- If the descriptor type of the descriptor set binding specified by `srcBinding` is `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT`, `srcArrayElement` must be an integer multiple of `4`

- If the descriptor type of the descriptor set binding specified by `dstBinding` is `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT`, `dstArrayElement` must be an integer multiple of `4`

- If the descriptor type of the descriptor set binding specified by either `srcBinding` or `dstBinding` is `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT`, `descriptorCount` must be an integer multiple of `4`

- If `srcSet`’s layout was created with the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` flag set, then `dstSet`’s layout must also have been created with the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` flag set

- If `srcSet`’s layout was created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` flag set, then `dstSet`’s layout must also have been created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` flag set

- If the descriptor pool from which `srcSet` was allocated was created with the `VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT` flag set, then the descriptor pool from which `dstSet` was allocated must also have been created with the `VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT` flag set

- If the descriptor pool from which `srcSet` was allocated was created without the `VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT` flag set, then the descriptor pool from which `dstSet` was allocated must also have been created without the `VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT` flag set

- If the descriptor type of the descriptor set binding specified by `dstBinding` is `VK_DESCRIPTOR_TYPE_SAMPLER`, then `dstSet` must not have been allocated with a layout that included immutable samplers for `dstBinding`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_COPY_DESCRIPTOR_SET`

- `pNext` must be `NULL`

- `srcSet` must be a valid VkDescriptorSet handle

- `dstSet` must be a valid VkDescriptorSet handle

- Both of `dstSet`, and `srcSet` must have been created, allocated, or retrieved from the same VkDevice

#### 13.2.5. Descriptor Update Templates

A descriptor update template specifies a mapping from descriptor update information in host memory to descriptors in a descriptor set. It is designed to avoid passing redundant information to the driver when frequently updating the same set of descriptors in descriptor sets.

Descriptor update template objects are represented by `VkDescriptorUpdateTemplate` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkDescriptorUpdateTemplate)

or the equivalent

    typedef VkDescriptorUpdateTemplate VkDescriptorUpdateTemplateKHR;

#### 13.2.6. Descriptor Set Updates with Templates

Updating a large `VkDescriptorSet` array can be an expensive operation since an application must specify one VkWriteDescriptorSet structure for each descriptor or descriptor array to update, each of which re-specifies the same state when updating the same descriptor in multiple descriptor sets. For cases when an application wishes to update the same set of descriptors in multiple descriptor sets allocated using the same `VkDescriptorSetLayout`, vkUpdateDescriptorSetWithTemplate can be used as a replacement for vkUpdateDescriptorSets.

`VkDescriptorUpdateTemplate` allows implementations to convert a set of descriptor update operations on a single descriptor set to an internal format that, in conjunction with vkUpdateDescriptorSetWithTemplate or vkCmdPushDescriptorSetWithTemplateKHR , can be more efficient compared to calling vkUpdateDescriptorSets or vkCmdPushDescriptorSetKHR . The descriptors themselves are not specified in the `VkDescriptorUpdateTemplate`, rather, offsets into an application provided pointer to host memory are specified, which are combined with a pointer passed to vkUpdateDescriptorSetWithTemplate or vkCmdPushDescriptorSetWithTemplateKHR . This allows large batches of updates to be executed without having to convert application data structures into a strictly-defined Vulkan data structure.

To create a descriptor update template, call:

    VkResult vkCreateDescriptorUpdateTemplate(
        VkDevice                                    device,
        const VkDescriptorUpdateTemplateCreateInfo* pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkDescriptorUpdateTemplate*                 pDescriptorUpdateTemplate);

or the equivalent command

    VkResult vkCreateDescriptorUpdateTemplateKHR(
        VkDevice                                    device,
        const VkDescriptorUpdateTemplateCreateInfo* pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkDescriptorUpdateTemplate*                 pDescriptorUpdateTemplate);

- `device` is the logical device that creates the descriptor update template.

- `pCreateInfo` is a pointer to a VkDescriptorUpdateTemplateCreateInfo structure specifying the set of descriptors to update with a single call to vkCmdPushDescriptorSetWithTemplateKHR or vkUpdateDescriptorSetWithTemplate.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pDescriptorUpdateTemplate` is a pointer to a `VkDescriptorUpdateTemplate` handle in which the resulting descriptor update template object is returned.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkDescriptorUpdateTemplateCreateInfo structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pDescriptorUpdateTemplate` must be a valid pointer to a VkDescriptorUpdateTemplate handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The VkDescriptorUpdateTemplateCreateInfo structure is defined as:

    typedef struct VkDescriptorUpdateTemplateCreateInfo {
        VkStructureType                           sType;
        const void*                               pNext;
        VkDescriptorUpdateTemplateCreateFlags     flags;
        uint32_t                                  descriptorUpdateEntryCount;
        const VkDescriptorUpdateTemplateEntry*    pDescriptorUpdateEntries;
        VkDescriptorUpdateTemplateType            templateType;
        VkDescriptorSetLayout                     descriptorSetLayout;
        VkPipelineBindPoint                       pipelineBindPoint;
        VkPipelineLayout                          pipelineLayout;
        uint32_t                                  set;
    } VkDescriptorUpdateTemplateCreateInfo;

or the equivalent

    typedef VkDescriptorUpdateTemplateCreateInfo VkDescriptorUpdateTemplateCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `descriptorUpdateEntryCount` is the number of elements in the `pDescriptorUpdateEntries` array.

- `pDescriptorUpdateEntries` is a pointer to an array of VkDescriptorUpdateTemplateEntry structures describing the descriptors to be updated by the descriptor update template.

- `templateType` Specifies the type of the descriptor update template. If set to `VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_DESCRIPTOR_SET` it can only be used to update descriptor sets with a fixed `descriptorSetLayout`. If set to `VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_PUSH_DESCRIPTORS_KHR` it can only be used to push descriptor sets using the provided `pipelineBindPoint`, `pipelineLayout`, and `set` number.

- `descriptorSetLayout` is the descriptor set layout the parameter update template will be used with. All descriptor sets which are going to be updated through the newly created descriptor update template must be created with this layout. `descriptorSetLayout` is the descriptor set layout used to build the descriptor update template. All descriptor sets which are going to be updated through the newly created descriptor update template must be created with a layout that matches (is the same as, or defined identically to) this layout. This parameter is ignored if `templateType` is not `VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_DESCRIPTOR_SET`.

- `pipelineBindPoint` is a VkPipelineBindPoint indicating whether the descriptors will be used by graphics pipelines or compute pipelines. This parameter is ignored if `templateType` is not `VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_PUSH_DESCRIPTORS_KHR`

- `pipelineLayout` is a VkPipelineLayout object used to program the bindings. This parameter is ignored if `templateType` is not `VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_PUSH_DESCRIPTORS_KHR`

- `set` is the set number of the descriptor set in the pipeline layout that will be updated. This parameter is ignored if `templateType` is not `VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_PUSH_DESCRIPTORS_KHR`

Valid Usage

- If `templateType` is `VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_DESCRIPTOR_SET`, `descriptorSetLayout` must be a valid `VkDescriptorSetLayout` handle

- If `templateType` is `VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_PUSH_DESCRIPTORS_KHR`, `pipelineBindPoint` must be a valid VkPipelineBindPoint value

- If `templateType` is `VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_PUSH_DESCRIPTORS_KHR`, `pipelineLayout` must be a valid `VkPipelineLayout` handle

- If `templateType` is `VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_PUSH_DESCRIPTORS_KHR`, `set` must be the unique set number in the pipeline layout that uses a descriptor set layout that was created with `VK_DESCRIPTOR_SET_LAYOUT_CREATE_PUSH_DESCRIPTOR_BIT_KHR`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_CREATE_INFO`

- `pNext` must be `NULL`

- `flags` must be `0`

- `pDescriptorUpdateEntries` must be a valid pointer to an array of `descriptorUpdateEntryCount` valid VkDescriptorUpdateTemplateEntry structures

- `templateType` must be a valid VkDescriptorUpdateTemplateType value

- `descriptorUpdateEntryCount` must be greater than `0`

- Both of `descriptorSetLayout`, and `pipelineLayout` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

    typedef VkFlags VkDescriptorUpdateTemplateCreateFlags;

or the equivalent

    typedef VkDescriptorUpdateTemplateCreateFlags VkDescriptorUpdateTemplateCreateFlagsKHR;

`VkDescriptorUpdateTemplateCreateFlags` is a bitmask type for setting a mask, but is currently reserved for future use.

The descriptor update template type is determined by the VkDescriptorUpdateTemplateCreateInfo::`templateType` property, which takes the following values:

    typedef enum VkDescriptorUpdateTemplateType {
        VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_DESCRIPTOR_SET = 0,
        VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_PUSH_DESCRIPTORS_KHR = 1,
        VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_DESCRIPTOR_SET_KHR = VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_DESCRIPTOR_SET,
        VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_MAX_ENUM = 0x7FFFFFFF
    } VkDescriptorUpdateTemplateType;

or the equivalent

    typedef VkDescriptorUpdateTemplateType VkDescriptorUpdateTemplateTypeKHR;

- `VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_DESCRIPTOR_SET` specifies that the descriptor update template will be used for descriptor set updates only.

- `VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_PUSH_DESCRIPTORS_KHR` specifies that the descriptor update template will be used for push descriptor updates only.

The `VkDescriptorUpdateTemplateEntry` structure is defined as:

    typedef struct VkDescriptorUpdateTemplateEntry {
        uint32_t            dstBinding;
        uint32_t            dstArrayElement;
        uint32_t            descriptorCount;
        VkDescriptorType    descriptorType;
        size_t              offset;
        size_t              stride;
    } VkDescriptorUpdateTemplateEntry;

or the equivalent

    typedef VkDescriptorUpdateTemplateEntry VkDescriptorUpdateTemplateEntryKHR;

- `dstBinding` is the descriptor binding to update when using this descriptor update template.

- `dstArrayElement` is the starting element in the array belonging to `dstBinding`. If the descriptor binding identified by `srcBinding` has a descriptor type of `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` then `dstArrayElement` specifies the starting byte offset to update.

- `descriptorCount` is the number of descriptors to update. If `descriptorCount` is greater than the number of remaining array elements in the destination binding, those affect consecutive bindings in a manner similar to VkWriteDescriptorSet above. If the descriptor binding identified by `dstBinding` has a descriptor type of `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` then `descriptorCount` specifies the number of bytes to update and the remaining array elements in the destination binding refer to the remaining number of bytes in it.

- `descriptorType` is a VkDescriptorType specifying the type of the descriptor.

- `offset` is the offset in bytes of the first binding in the raw data structure.

- `stride` is the stride in bytes between two consecutive array elements of the descriptor update informations in the raw data structure. The actual pointer ptr for each array element j of update entry i is computed using the following formula:

          const char *ptr = (const char *)pData + pDescriptorUpdateEntries[i].offset + j * pDescriptorUpdateEntries[i].stride

  The stride is useful in case the bindings are stored in structs along with other data. If `descriptorType` is `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` then the value of `stride` is ignored and the stride is assumed to be `1`, i.e. the descriptor update information for them is always specified as a contiguous range.

Valid Usage

- `dstBinding` must be a valid binding in the descriptor set layout implicitly specified when using a descriptor update template to update descriptors.

- `dstArrayElement` and `descriptorCount` must be less than or equal to the number of array elements in the descriptor set binding implicitly specified when using a descriptor update template to update descriptors, and all applicable consecutive bindings, as described by consecutive binding updates

- If `descriptor` type is `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT`, `dstArrayElement` must be an integer multiple of `4`

- If `descriptor` type is `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT`, `descriptorCount` must be an integer multiple of `4`

Valid Usage (Implicit)

- `descriptorType` must be a valid VkDescriptorType value

To destroy a descriptor update template, call:

    void vkDestroyDescriptorUpdateTemplate(
        VkDevice                                    device,
        VkDescriptorUpdateTemplate                  descriptorUpdateTemplate,
        const VkAllocationCallbacks*                pAllocator);

or the equivalent command

    void vkDestroyDescriptorUpdateTemplateKHR(
        VkDevice                                    device,
        VkDescriptorUpdateTemplate                  descriptorUpdateTemplate,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that has been used to create the descriptor update template

- `descriptorUpdateTemplate` is the descriptor update template to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage

- If `VkAllocationCallbacks` were provided when `descriptorSetLayout` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `descriptorSetLayout` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `descriptorUpdateTemplate` is not VK_NULL_HANDLE, `descriptorUpdateTemplate` must be a valid VkDescriptorUpdateTemplate handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- If `descriptorUpdateTemplate` is a valid handle, it must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `descriptorUpdateTemplate` must be externally synchronized

Once a `VkDescriptorUpdateTemplate` has been created, descriptor sets can be updated by calling:

    void vkUpdateDescriptorSetWithTemplate(
        VkDevice                                    device,
        VkDescriptorSet                             descriptorSet,
        VkDescriptorUpdateTemplate                  descriptorUpdateTemplate,
        const void*                                 pData);

or the equivalent command

    void vkUpdateDescriptorSetWithTemplateKHR(
        VkDevice                                    device,
        VkDescriptorSet                             descriptorSet,
        VkDescriptorUpdateTemplate                  descriptorUpdateTemplate,
        const void*                                 pData);

- `device` is the logical device that updates the descriptor sets.

- `descriptorSet` is the descriptor set to update

- `descriptorUpdateTemplate` is a VkDescriptorUpdateTemplate object specifying the update mapping between `pData` and the descriptor set to update.

- `pData` is a pointer to memory containing one or more VkDescriptorImageInfo, VkDescriptorBufferInfo, or VkBufferView structures used to write the descriptors.

Valid Usage

- `pData` must be a valid pointer to a memory containing one or more valid instances of VkDescriptorImageInfo, VkDescriptorBufferInfo, or VkBufferView in a layout defined by `descriptorUpdateTemplate` when it was created with vkCreateDescriptorUpdateTemplate

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `descriptorSet` must be a valid VkDescriptorSet handle

- `descriptorUpdateTemplate` must be a valid VkDescriptorUpdateTemplate handle

- `descriptorUpdateTemplate` must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `descriptorSet` must be externally synchronized

API example

    struct AppBufferView {
        VkBufferView bufferView;
        uint32_t     applicationRelatedInformation;
    };

    struct AppDataStructure
    {
        VkDescriptorImageInfo  imageInfo;          // a single image info
        VkDescriptorBufferInfo bufferInfoArray[3]; // 3 buffer infos in an array
        AppBufferView          bufferView[2];      // An application defined structure containing a bufferView
        // ... some more application related data
    };

    const VkDescriptorUpdateTemplateEntry descriptorUpdateTemplateEntries[] =
    {
        // binding to a single image descriptor
        {
            0,                                           // binding
            0,                                           // dstArrayElement
            1,                                           // descriptorCount
            VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER,   // descriptorType
            offsetof(AppDataStructure, imageInfo),       // offset
            0                                            // stride is not required if descriptorCount is 1
        },

        // binding to an array of buffer descriptors
        {
            1,                                           // binding
            0,                                           // dstArrayElement
            3,                                           // descriptorCount
            VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER,           // descriptorType
            offsetof(AppDataStructure, bufferInfoArray), // offset
            sizeof(VkDescriptorBufferInfo)               // stride, descriptor buffer infos are compact
        },

        // binding to an array of buffer views
        {
            2,                                           // binding
            0,                                           // dstArrayElement
            2,                                           // descriptorCount
            VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER,     // descriptorType
            offsetof(AppDataStructure, bufferView) +
              offsetof(AppBufferView, bufferView),       // offset
            sizeof(AppBufferView)                        // stride, bufferViews do not have to be compact
        },
    };

    // create a descriptor update template for descriptor set updates
    const VkDescriptorUpdateTemplateCreateInfo createInfo =
    {
        VK_STRUCTURE_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_CREATE_INFO,  // sType
        NULL,                                                      // pNext
        0,                                                         // flags
        3,                                                         // descriptorUpdateEntryCount
        descriptorUpdateTemplateEntries,                           // pDescriptorUpdateEntries
        VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_DESCRIPTOR_SET,         // templateType
        myLayout,                                                  // descriptorSetLayout
        0,                                                         // pipelineBindPoint, ignored by given templateType
        0,                                                         // pipelineLayout, ignored by given templateType
        0,                                                         // set, ignored by given templateType
    };

    VkDescriptorUpdateTemplate myDescriptorUpdateTemplate;
    myResult = vkCreateDescriptorUpdateTemplate(
        myDevice,
        &createInfo,
        NULL,
        &myDescriptorUpdateTemplate);
    }

    AppDataStructure appData;

    // fill appData here or cache it in your engine
    vkUpdateDescriptorSetWithTemplate(myDevice, myDescriptorSet, myDescriptorUpdateTemplate, &appData);

#### 13.2.7. Descriptor Set Binding

To bind one or more descriptor sets to a command buffer, call:

    void vkCmdBindDescriptorSets(
        VkCommandBuffer                             commandBuffer,
        VkPipelineBindPoint                         pipelineBindPoint,
        VkPipelineLayout                            layout,
        uint32_t                                    firstSet,
        uint32_t                                    descriptorSetCount,
        const VkDescriptorSet*                      pDescriptorSets,
        uint32_t                                    dynamicOffsetCount,
        const uint32_t*                             pDynamicOffsets);

- `commandBuffer` is the command buffer that the descriptor sets will be bound to.

- `pipelineBindPoint` is a VkPipelineBindPoint indicating whether the descriptors will be used by graphics pipelines or compute pipelines. There is a separate set of bind points for each of graphics and compute, so binding one does not disturb the other.

- `layout` is a VkPipelineLayout object used to program the bindings.

- `firstSet` is the set number of the first descriptor set to be bound.

- `descriptorSetCount` is the number of elements in the `pDescriptorSets` array.

- `pDescriptorSets` is a pointer to an array of handles to VkDescriptorSet objects describing the descriptor sets to write to.

- `dynamicOffsetCount` is the number of dynamic offsets in the `pDynamicOffsets` array.

- `pDynamicOffsets` is a pointer to an array of `uint32_t` values specifying dynamic offsets.

`vkCmdBindDescriptorSets` causes the sets numbered [`firstSet`.. `firstSet`+`descriptorSetCount`-1] to use the bindings stored in `pDescriptorSets`[0..descriptorSetCount-1] for subsequent rendering commands (either compute or graphics, according to the `pipelineBindPoint`). Any bindings that were previously applied via these sets are no longer valid.

Once bound, a descriptor set affects rendering of subsequent graphics or compute commands in the command buffer until a different set is bound to the same set number, or else until the set is disturbed as described in Pipeline Layout Compatibility.

A compatible descriptor set must be bound for all set numbers that any shaders in a pipeline access, at the time that a draw or dispatch command is recorded to execute using that pipeline. However, if none of the shaders in a pipeline statically use any bindings with a particular set number, then no descriptor set need be bound for that set number, even if the pipeline layout includes a non-trivial descriptor set layout for that set number.

If any of the sets being bound include dynamic uniform or storage buffers, then `pDynamicOffsets` includes one element for each array element in each dynamic descriptor type binding in each set. Values are taken from `pDynamicOffsets` in an order such that all entries for set N come before set N+1; within a set, entries are ordered by the binding numbers in the descriptor set layouts; and within a binding array, elements are in order. `dynamicOffsetCount` must equal the total number of dynamic descriptors in the sets being bound.

The effective offset used for dynamic uniform and storage buffer bindings is the sum of the relative offset taken from `pDynamicOffsets`, and the base address of the buffer plus base offset in the descriptor set. The range of the dynamic uniform and storage buffer bindings is the buffer range as specified in the descriptor set.

Each of the `pDescriptorSets` must be compatible with the pipeline layout specified by `layout`. The layout used to program the bindings must also be compatible with the pipeline used in subsequent graphics or compute commands, as defined in the Pipeline Layout Compatibility section.

The descriptor set contents bound by a call to `vkCmdBindDescriptorSets` may be consumed at the following times:

- For descriptor bindings created with the `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT` bit set, the contents may be consumed when the command buffer is submitted to a queue, or during shader execution of the resulting draws and dispatches, or any time in between. Otherwise,

- during host execution of the command, or during shader execution of the resulting draws and dispatches, or any time in between.

Thus, the contents of a descriptor set binding must not be altered (overwritten by an update command, or freed) between the first point in time that it may be consumed, and when the command completes executing on the queue.

The contents of `pDynamicOffsets` are consumed immediately during execution of `vkCmdBindDescriptorSets`. Once all pending uses have completed, it is legal to update and reuse a descriptor set.

Valid Usage

- Each element of `pDescriptorSets` must have been allocated with a `VkDescriptorSetLayout` that matches (is the same as, or identically defined as) the `VkDescriptorSetLayout` at set n in `layout`, where n is the sum of `firstSet` and the index into `pDescriptorSets`

- `dynamicOffsetCount` must be equal to the total number of dynamic descriptors in `pDescriptorSets`

- The sum of `firstSet` and `descriptorSetCount` must be less than or equal to `VkPipelineLayoutCreateInfo`::`setLayoutCount` provided when `layout` was created

- `pipelineBindPoint` must be supported by the `commandBuffer`’s parent `VkCommandPool`’s queue family

- Each element of `pDynamicOffsets` which corresponds to a descriptor binding with type `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC` must be a multiple of `VkPhysicalDeviceLimits`::`minUniformBufferOffsetAlignment`

- Each element of `pDynamicOffsets` which corresponds to a descriptor binding with type `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC` must be a multiple of `VkPhysicalDeviceLimits`::`minStorageBufferOffsetAlignment`

- For each dynamic uniform or storage buffer binding in `pDescriptorSets`, the sum of the effective offset, as defined above, and the range of the binding must be less than or equal to the size of the buffer

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pipelineBindPoint` must be a valid VkPipelineBindPoint value

- `layout` must be a valid VkPipelineLayout handle

- `pDescriptorSets` must be a valid pointer to an array of `descriptorSetCount` valid VkDescriptorSet handles

- If `dynamicOffsetCount` is not `0`, `pDynamicOffsets` must be a valid pointer to an array of `dynamicOffsetCount` `uint32_t` values

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

- `descriptorSetCount` must be greater than `0`

- Each of `commandBuffer`, `layout`, and the elements of `pDescriptorSets` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute |

#### 13.2.8. Push Descriptor Updates

In addition to allocating descriptor sets and binding them to a command buffer, an application can record descriptor updates into the command buffer.

To push descriptor updates into a command buffer, call:

    void vkCmdPushDescriptorSetKHR(
        VkCommandBuffer                             commandBuffer,
        VkPipelineBindPoint                         pipelineBindPoint,
        VkPipelineLayout                            layout,
        uint32_t                                    set,
        uint32_t                                    descriptorWriteCount,
        const VkWriteDescriptorSet*                 pDescriptorWrites);

- `commandBuffer` is the command buffer that the descriptors will be recorded in.

- `pipelineBindPoint` is a VkPipelineBindPoint indicating whether the descriptors will be used by graphics pipelines or compute pipelines. There is a separate set of push descriptor bindings for each of graphics and compute, so binding one does not disturb the other.

- `layout` is a VkPipelineLayout object used to program the bindings.

- `set` is the set number of the descriptor set in the pipeline layout that will be updated.

- `descriptorWriteCount` is the number of elements in the `pDescriptorWrites` array.

- `pDescriptorWrites` is a pointer to an array of VkWriteDescriptorSet structures describing the descriptors to be updated.

Push descriptors are a small bank of descriptors whose storage is internally managed by the command buffer rather than being written into a descriptor set and later bound to a command buffer. Push descriptors allow for incremental updates of descriptors without managing the lifetime of descriptor sets.

When a command buffer begins recording, all push descriptors are undefined. Push descriptors can be updated incrementally and cause shaders to use the updated descriptors for subsequent rendering commands (either compute or graphics, according to the `pipelineBindPoint`) until the descriptor is overwritten, or else until the set is disturbed as described in Pipeline Layout Compatibility. When the set is disturbed or push descriptors with a different descriptor set layout are set, all push descriptors are undefined.

Push descriptors that are statically used by a pipeline must not be undefined at the time that a draw or dispatch command is recorded to execute using that pipeline. This includes immutable sampler descriptors, which must be pushed before they are accessed by a pipeline (the immutable samplers are pushed, rather than the samplers in `pDescriptorWrites`). Push descriptors that are not statically used can remain undefined.

Push descriptors do not use dynamic offsets. Instead, the corresponding non-dynamic descriptor types can be used and the `offset` member of VkDescriptorBufferInfo can be changed each time the descriptor is written.

Each element of `pDescriptorWrites` is interpreted as in VkWriteDescriptorSet, except the `dstSet` member is ignored.

To push an immutable sampler, use a VkWriteDescriptorSet with `dstBinding` and `dstArrayElement` selecting the immutable sampler’s binding. If the descriptor type is `VK_DESCRIPTOR_TYPE_SAMPLER`, the `pImageInfo` parameter is ignored and the immutable sampler is taken from the push descriptor set layout in the pipeline layout. If the descriptor type is `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, the `sampler` member of the `pImageInfo` parameter is ignored and the immutable sampler is taken from the push descriptor set layout in the pipeline layout.

Valid Usage

- `pipelineBindPoint` must be supported by the `commandBuffer`’s parent `VkCommandPool`’s queue family

- `set` must be less than `VkPipelineLayoutCreateInfo`::`setLayoutCount` provided when `layout` was created

- `set` must be the unique set number in the pipeline layout that uses a descriptor set layout that was created with `VK_DESCRIPTOR_SET_LAYOUT_CREATE_PUSH_DESCRIPTOR_BIT_KHR`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pipelineBindPoint` must be a valid VkPipelineBindPoint value

- `layout` must be a valid VkPipelineLayout handle

- `pDescriptorWrites` must be a valid pointer to an array of `descriptorWriteCount` valid VkWriteDescriptorSet structures

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

- `descriptorWriteCount` must be greater than `0`

- Both of `commandBuffer`, and `layout` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute |

#### 13.2.9. Push Descriptor Updates with Descriptor Update Templates

It is also possible to use a descriptor update template to specify the push descriptors to update. To do so, call:

    void vkCmdPushDescriptorSetWithTemplateKHR(
        VkCommandBuffer                             commandBuffer,
        VkDescriptorUpdateTemplate                  descriptorUpdateTemplate,
        VkPipelineLayout                            layout,
        uint32_t                                    set,
        const void*                                 pData);

- `commandBuffer` is the command buffer that the descriptors will be recorded in.

- `descriptorUpdateTemplate` is a descriptor update template defining how to interpret the descriptor information in `pData`.

- `layout` is a VkPipelineLayout object used to program the bindings. It must be compatible with the layout used to create the `descriptorUpdateTemplate` handle.

- `set` is the set number of the descriptor set in the pipeline layout that will be updated. This must be the same number used to create the `descriptorUpdateTemplate` handle.

- `pData` is a pointer to memory containing descriptors for the templated update.

Valid Usage

- The `pipelineBindPoint` specified during the creation of the descriptor update template must be supported by the `commandBuffer`’s parent `VkCommandPool`’s queue family

- `pData` must be a valid pointer to a memory containing one or more valid instances of VkDescriptorImageInfo, VkDescriptorBufferInfo, or VkBufferView in a layout defined by `descriptorUpdateTemplate` when it was created with vkCreateDescriptorUpdateTemplateKHR

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `descriptorUpdateTemplate` must be a valid VkDescriptorUpdateTemplate handle

- `layout` must be a valid VkPipelineLayout handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

- Each of `commandBuffer`, `descriptorUpdateTemplate`, and `layout` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute |

API example

    struct AppDataStructure
    {
        VkDescriptorImageInfo  imageInfo;          // a single image info
        // ... some more application related data
    };

    const VkDescriptorUpdateTemplateEntry descriptorUpdateTemplateEntries[] =
    {
        // binding to a single image descriptor
        {
            0,                                           // binding
            0,                                           // dstArrayElement
            1,                                           // descriptorCount
            VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER,   // descriptorType
            offsetof(AppDataStructure, imageInfo),       // offset
            0                                            // stride is not required if descriptorCount is 1
        }
    };

    // create a descriptor update template for descriptor set updates
    const VkDescriptorUpdateTemplateCreateInfo createInfo =
    {
        VK_STRUCTURE_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_CREATE_INFO,  // sType
        NULL,                                                      // pNext
        0,                                                         // flags
        1,                                                         // descriptorUpdateEntryCount
        descriptorUpdateTemplateEntries,                           // pDescriptorUpdateEntries
        VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_PUSH_DESCRIPTORS_KHR,   // templateType
        0,                                                         // descriptorSetLayout, ignored by given templateType
        VK_PIPELINE_BIND_POINT_GRAPHICS,                           // pipelineBindPoint
        myPipelineLayout,                                          // pipelineLayout
        0,                                                         // set
    };

    VkDescriptorUpdateTemplate myDescriptorUpdateTemplate;
    myResult = vkCreateDescriptorUpdateTemplate(
        myDevice,
        &createInfo,
        NULL,
        &myDescriptorUpdateTemplate);
    }

    AppDataStructure appData;
    // fill appData here or cache it in your engine
    vkCmdPushDescriptorSetWithTemplateKHR(myCmdBuffer, myDescriptorUpdateTemplate, myPipelineLayout, 0,&appData);

#### 13.2.10. Push Constant Updates

As described above in section Pipeline Layouts, the pipeline layout defines shader push constants which are updated via Vulkan commands rather than via writes to memory or copy commands.

| Note Push constants represent a high speed path to modify constant data in pipelines that is expected to outperform memory-backed resource updates.

The values of push constants are undefined at the start of a command buffer.

To update push constants, call:

    void vkCmdPushConstants(
        VkCommandBuffer                             commandBuffer,
        VkPipelineLayout                            layout,
        VkShaderStageFlags                          stageFlags,
        uint32_t                                    offset,
        uint32_t                                    size,
        const void*                                 pValues);

- `commandBuffer` is the command buffer in which the push constant update will be recorded.

- `layout` is the pipeline layout used to program the push constant updates.

- `stageFlags` is a bitmask of VkShaderStageFlagBits specifying the shader stages that will use the push constants in the updated range.

- `offset` is the start offset of the push constant range to update, in units of bytes.

- `size` is the size of the push constant range to update, in units of bytes.

- `pValues` is a pointer to an array of `size` bytes containing the new push constant values.

| Note As `stageFlags` needs to include all flags the relevant push constant ranges were created with, any flags that are not supported by the queue family that the VkCommandPool used to allocate `commandBuffer` was created on are ignored.

Valid Usage

- For each byte in the range specified by `offset` and `size` and for each shader stage in `stageFlags`, there must be a push constant range in `layout` that includes that byte and that stage

- For each byte in the range specified by `offset` and `size` and for each push constant range that overlaps that byte, `stageFlags` must include all stages in that push constant range’s VkPushConstantRange::`stageFlags`

- `offset` must be a multiple of `4`

- `size` must be a multiple of `4`

- `offset` must be less than `VkPhysicalDeviceLimits`::`maxPushConstantsSize`

- `size` must be less than or equal to `VkPhysicalDeviceLimits`::`maxPushConstantsSize` minus `offset`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `layout` must be a valid VkPipelineLayout handle

- `stageFlags` must be a valid combination of VkShaderStageFlagBits values

- `stageFlags` must not be `0`

- `pValues` must be a valid pointer to an array of `size` bytes

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

- `size` must be greater than `0`

- Both of `commandBuffer`, and `layout` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute |

### 13.3. Physical Storage Buffer Access

To query a 64-bit buffer device address value through which buffer memory can be accessed in a shader, call:

    VkDeviceAddress vkGetBufferDeviceAddress(
        VkDevice                                    device,
        const VkBufferDeviceAddressInfo*            pInfo);

or the equivalent command

    VkDeviceAddress vkGetBufferDeviceAddressKHR(
        VkDevice                                    device,
        const VkBufferDeviceAddressInfo*            pInfo);

or the equivalent command

    VkDeviceAddress vkGetBufferDeviceAddressEXT(
        VkDevice                                    device,
        const VkBufferDeviceAddressInfo*            pInfo);

- `device` is the logical device that the buffer was created on.

- `pInfo` is a pointer to a VkBufferDeviceAddressInfo structure specifying the buffer to retrieve an address for.

The 64-bit return value is an address of the start of `pInfo->buffer`. The address range starting at this value and whose size is the size of the buffer can be used in a shader to access the memory bound to that buffer, using the `SPV_KHR_physical_storage_buffer` extension or the equivalent `SPV_EXT_physical_storage_buffer` extension and the `PhysicalStorageBuffer` storage class. For example, this value can be stored in a uniform buffer, and the shader can read the value from the uniform buffer and use it to do a dependent read/write to this buffer. A value of zero is reserved as a “null” pointer and must not be returned as a valid buffer device address. All loads, stores, and atomics in a shader through `PhysicalStorageBuffer` pointers must access addresses in the address range of some buffer.

If the buffer was created with a non-zero value of VkBufferOpaqueCaptureAddressCreateInfo::`opaqueCaptureAddress` or VkBufferDeviceAddressCreateInfoEXT::`deviceAddress` the return value will be the same address that was returned at capture time.

Valid Usage

- The bufferDeviceAddress or `VkPhysicalDeviceBufferDeviceAddressFeaturesEXT`::`bufferDeviceAddress` feature must be enabled

- If `device` was created with multiple physical devices, then the bufferDeviceAddressMultiDevice or `VkPhysicalDeviceBufferDeviceAddressFeaturesEXT`::`bufferDeviceAddressMultiDevice` feature must be enabled

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pInfo` must be a valid pointer to a valid VkBufferDeviceAddressInfo structure

The `VkBufferDeviceAddressInfo` structure is defined as:

    typedef struct VkBufferDeviceAddressInfo {
        VkStructureType    sType;
        const void*        pNext;
        VkBuffer           buffer;
    } VkBufferDeviceAddressInfo;

or the equivalent

    typedef VkBufferDeviceAddressInfo VkBufferDeviceAddressInfoKHR;

or the equivalent

    typedef VkBufferDeviceAddressInfo VkBufferDeviceAddressInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `buffer` specifies the buffer whose address is being queried.

Valid Usage

- If `buffer` is non-sparse and was not created with the `VK_BUFFER_CREATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT` flag, then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `buffer` must have been created with `VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_BUFFER_DEVICE_ADDRESS_INFO`

- `pNext` must be `NULL`

- `buffer` must be a valid VkBuffer handle

To query a 64-bit buffer opaque capture address, call:

    uint64_t vkGetBufferOpaqueCaptureAddress(
        VkDevice                                    device,
        const VkBufferDeviceAddressInfo*            pInfo);

or the equivalent command

    uint64_t vkGetBufferOpaqueCaptureAddressKHR(
        VkDevice                                    device,
        const VkBufferDeviceAddressInfo*            pInfo);

- `device` is the logical device that the buffer was created on.

- `pInfo` is a pointer to a VkBufferDeviceAddressInfo structure specifying the buffer to retrieve an address for.

The 64-bit return value is an opaque capture address of the start of `pInfo->buffer`.

If the buffer was created with a non-zero value of VkBufferOpaqueCaptureAddressCreateInfo::`opaqueCaptureAddress` the return value must be the same address.

Valid Usage

- The bufferDeviceAddress feature must be enabled

- If `device` was created with multiple physical devices, then the bufferDeviceAddressMultiDevice feature must be enabled

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pInfo` must be a valid pointer to a valid VkBufferDeviceAddressInfo structure

## 14. Shader Interfaces

When a pipeline is created, the set of shaders specified in the corresponding `Vk*PipelineCreateInfo` structure are implicitly linked at a number of different interfaces.

- Shader Input and Output Interface

- Vertex Input Interface

- Fragment Output Interface

- Fragment Input Attachment Interface

- Shader Resource Interface

Interface definitions make use of the following SPIR-V decorations:

- `DescriptorSet` and `Binding`

- `Location`, `Component`, and `Index`

- `Flat`, `NoPerspective`, `Centroid`, and `Sample`

- `Block` and `BufferBlock`

- `InputAttachmentIndex`

- `Offset`, `ArrayStride`, and `MatrixStride`

- `BuiltIn`

- `PassthroughNV`

This specification describes valid uses for Vulkan of these decorations. Any other use of one of these decorations is invalid.

### 14.1. Shader Input and Output Interfaces

When multiple stages are present in a pipeline, the outputs of one stage form an interface with the inputs of the next stage. When such an interface involves a shader, shader outputs are matched against the inputs of the next stage, and shader inputs are matched against the outputs of the previous stage.

All the variables forming the shader input and output interfaces are listed as operands to the `OpEntryPoint` instruction and are declared with the `Input` or `Output` storage classes, respectively, in the SPIR-V module. These generally form the interfaces between consecutive shader stages, regardless of any non-shader stages between the consecutive shader stages.

There are two classes of variables that can be matched between shader stages, built-in variables and user-defined variables. Each class has a different set of matching criteria.

`Output` variables of a shader stage have undefined values until the shader writes to them or uses the `Initializer` operand when declaring the variable.

#### 14.1.1. Built-in Interface Block

Shader built-in variables meeting the following requirements define the built-in interface block. They must

- be explicitly declared (there are no implicit built-ins),

- be identified with a `BuiltIn` decoration,

- form object types as described in the Built-in Variables section, and

- be declared in a block whose top-level members are the built-ins.

There must be no more than one built-in interface block per shader per interface.

Built-ins must not have any `Location` or `Component` decorations.

#### 14.1.2. User-defined Variable Interface

The non-built-in variables listed by `OpEntryPoint` with the `Input` or `Output` storage class form the user-defined variable interface. These must have SPIR-V numerical types or, recursively, composite types of such types. By default, the components of such types have a width of 32 or 64 bits. If an implementation supports storageInputOutput16, components can also have a width of 16 bits. These variables must be identified with a `Location` decoration and can also be identified with a `Component` decoration.

#### 14.1.3. Interface Matching

Interface matching rules only apply to built-ins when they are declared as members of the built-in interface block.

Tessellation control and mesh shader per-vertex output variables and blocks, and tessellation control, tessellation evaluation, and geometry shader per-vertex input variables and blocks are required to be declared as arrays, with each element representing input or output values for a single vertex of a multi-vertex primitive. For the purposes of interface matching, the outermost array dimension of such variables and blocks is ignored.

A user-defined output variable is considered to match an input variable in the subsequent stage if the two variables are declared with the same `Location` and `Component` decoration and match in type and decoration, except that interpolation decorations are not required to match. `XfbBuffer`, `XfbStride`, `Offset`, and `Stream` are also not required to match for the purposes of interface matching. For the purposes of interface matching, variables declared without a `Component` decoration are considered to have a `Component` decoration of zero.

| Note Matching rules for passthrough geometry shaders are slightly different and are described in the Passthrough Interface Matching section.

Variables or block members declared as structures are considered to match in type if and only if the structure members match in type, decoration, number, and declaration order. Variables or block members declared as arrays are considered to match in type only if both declarations specify the same element type and size.

At an interface between two non-fragment shader stages, the built-in interface block must match exactly, as described above, except for per-view outputs as described in Mesh Shader Per-View Outputs. At an interface involving the fragment shader inputs, the presence or absence of any built-in output does not affect the interface matching.

At an interface between two shader stages, the user-defined variable interface must match exactly, as described above.

Any input value to a shader stage is well-defined as long as the preceding stages writes to a matching output, as described above.

Additionally, scalar and vector inputs are well-defined if there is a corresponding output satisfying all of the following conditions:

- the input and output match exactly in decoration,

- the output is a vector with the same basic type and has at least as many components as the input, and

- the common component type of the input and output is 16-bit integer or floating-point, or 32-bit integer or floating-point (64-bit component types are excluded).

In this case, the components of the input will be taken from the first components of the output, and any extra components of the output will be ignored.

#### 14.1.4. Location Assignment

This section describes how many locations are consumed by a given type. As mentioned above, some inputs and outputs have an additional level of arrayness relative to other shader inputs and outputs. This outer array level is removed from the type before considering how many locations the type consumes.

The `Location` value specifies an interface slot comprised of a 32-bit four-component vector conveyed between stages. The `Component` specifies components within these vector locations. Only types with widths of 16, 32 or 64 are supported in shader interfaces.

Inputs and outputs of the following types consume a single interface location:

- 16-bit scalar and vector types, and

- 32-bit scalar and vector types, and

- 64-bit scalar and 2-component vector types.

64-bit three- and four-component vectors consume two consecutive locations.

If a declared input or output is an array of size n and each element takes m locations, it will be assigned m × n consecutive locations starting with the location specified.

If the declared input or output is an n × m 16-, 32- or 64-bit matrix, it will be assigned multiple locations starting with the location specified. The number of locations assigned for each matrix will be the same as for an n-element array of m-component vectors.

The layout of a structure type used as an `Input` or `Output` depends on whether it is also a `Block` (i.e. has a `Block` decoration).

If it is a not a `Block`, then the structure type must have a `Location` decoration. Its members are assigned consecutive locations in their declaration order, with the first member assigned to the location specified for the structure type. The members, and their nested types, must not themselves have `Location` decorations.

If the structure type is a `Block` but without a `Location`, then each of its members must have a `Location` decoration. If it is a `Block` with a `Location` decoration, then its members are assigned consecutive locations in declaration order, starting from the first member which is initially assigned the location specified for the `Block`. Any member with its own `Location` decoration is assigned that location. Each remaining member is assigned the location after the immediately preceding member in declaration order.

The locations consumed by block and structure members are determined by applying the rules above in a depth-first traversal of the instantiated members as though the structure or block member were declared as an input or output variable of the same type.

Any two inputs listed as operands on the same `OpEntryPoint` must not be assigned the same location, either explicitly or implicitly. Any two outputs listed as operands on the same `OpEntryPoint` must not be assigned the same location, either explicitly or implicitly.

The number of input and output locations available for a shader input or output interface are limited, and dependent on the shader stage as described in Shader Input and Output Locations. All variables in both the built-in interface block and the user-defined variable interface count against these limits. Each effective `Location` must have a value less than the number of locations available for the given interface, as specified in the "Locations Available" column in Shader Input and Output Locations.

Table 18. Shader Input and Output Locations
Shader Interface | Locations Available
--- | ---
vertex input | `maxVertexInputAttributes`
vertex output | `maxVertexOutputComponents` / 4
tessellation control input | `maxTessellationControlPerVertexInputComponents` / 4
tessellation control output | `maxTessellationControlPerVertexOutputComponents` / 4
tessellation evaluation input | `maxTessellationEvaluationInputComponents` / 4
tessellation evaluation output | `maxTessellationEvaluationOutputComponents` / 4
geometry input | `maxGeometryInputComponents` / 4
geometry output | `maxGeometryOutputComponents` / 4
fragment input | `maxFragmentInputComponents` / 4
fragment output | `maxFragmentOutputAttachments`

#### 14.1.5. Component Assignment

The `Component` decoration allows the `Location` to be more finely specified for scalars and vectors, down to the individual components within a location that are consumed. The components within a location are 0, 1, 2, and 3. A variable or block member starting at component N will consume components N, N+1, N+2, …​ up through its size. For 16-, and 32-bit types, it is invalid if this sequence of components gets larger than 3. A scalar 64-bit type will consume two of these components in sequence, and a two-component 64-bit vector type will consume all four components available within a location. A three- or four-component 64-bit vector type must not specify a `Component` decoration. A three-component 64-bit vector type will consume all four components of the first location and components 0 and 1 of the second location. This leaves components 2 and 3 available for other component-qualified declarations.

A scalar or two-component 64-bit data type must not specify a `Component` decoration of 1 or 3. A `Component` decoration must not be specified for any type that is not a scalar or vector.

### 14.2. Vertex Input Interface

When the vertex stage is present in a pipeline, the vertex shader input variables form an interface with the vertex input attributes. The vertex shader input variables are matched by the `Location` and `Component` decorations to the vertex input attributes specified in the `pVertexInputState` member of the VkGraphicsPipelineCreateInfo structure.

The vertex shader input variables listed by `OpEntryPoint` with the `Input` storage class form the vertex input interface. These variables must be identified with a `Location` decoration and can also be identified with a `Component` decoration.

For the purposes of interface matching: variables declared without a `Component` decoration are considered to have a `Component` decoration of zero. The number of available vertex input locations is given by the `maxVertexInputAttributes` member of the `VkPhysicalDeviceLimits` structure.

See Attribute Location and Component Assignment for details.

All vertex shader inputs declared as above must have a corresponding attribute and binding in the pipeline.

### 14.3. Fragment Output Interface

When the fragment stage is present in a pipeline, the fragment shader outputs form an interface with the output attachments of the current subpass. The fragment shader output variables are matched by the `Location` and `Component` decorations to the color attachments specified in the `pColorAttachments` array of the VkSubpassDescription structure describing the subpass that the fragment shader is executed in.

The fragment shader output variables listed by `OpEntryPoint` with the `Output` storage class form the fragment output interface. These variables must be identified with a `Location` decoration. They can also be identified with a `Component` decoration and/or an `Index` decoration. For the purposes of interface matching: variables declared without a `Component` decoration are considered to have a `Component` decoration of zero, and variables declared without an `Index` decoration are considered to have an `Index` decoration of zero.

A fragment shader output variable identified with a `Location` decoration of i is directed to the color attachment indicated by `pColorAttachments`[i], after passing through the blending unit as described in Blending, if enabled. Locations are consumed as described in Location Assignment. The number of available fragment output locations is given by the `maxFragmentOutputAttachments` member of the `VkPhysicalDeviceLimits` structure.

Components of the output variables are assigned as described in Component Assignment. Output components identified as 0, 1, 2, and 3 will be directed to the R, G, B, and A inputs to the blending unit, respectively, or to the output attachment if blending is disabled. If two variables are placed within the same location, they must have the same underlying type (floating-point or integer). The input values to blending or color attachment writes are undefined for components which do not correspond to a fragment shader output.

Fragment outputs identified with an `Index` of zero are directed to the first input of the blending unit associated with the corresponding `Location`. Outputs identified with an `Index` of one are directed to the second input of the corresponding blending unit.

No component aliasing of output variables is allowed, that is there must not be two output variables which have the same location, component, and index, either explicitly declared or implied.

Output values written by a fragment shader must be declared with either `OpTypeFloat` or `OpTypeInt`, and a `Width` of 32. If `storageInputOutput16` is supported, output values written by a fragment shader can be also declared with either `OpTypeFloat` or `OpTypeInt` and a `Width` of 16. Composites of these types are also permitted. If the color attachment has a signed or unsigned normalized fixed-point format, color values are assumed to be floating-point and are converted to fixed-point as described in Conversion from Floating-Point to Normalized Fixed-Point; If the color attachment has an integer format, color values are assumed to be integers and converted to the bit-depth of the target. Any value that cannot be represented in the attachment’s format is undefined. For any other attachment format no conversion is performed. If the type of the values written by the fragment shader do not match the format of the corresponding color attachment, the resulting values are undefined for those components.

### 14.4. Fragment Input Attachment Interface

When a fragment stage is present in a pipeline, the fragment shader subpass inputs form an interface with the input attachments of the current subpass. The fragment shader subpass input variables are matched by `InputAttachmentIndex` decorations to the input attachments specified in the `pInputAttachments` array of the VkSubpassDescription structure describing the subpass that the fragment shader is executed in.

The fragment shader subpass input variables with the `UniformConstant` storage class and a decoration of `InputAttachmentIndex` that are statically used by `OpEntryPoint` form the fragment input attachment interface. These variables must be declared with a type of `OpTypeImage`, a `Dim` operand of `SubpassData`, and a `Sampled` operand of 2.

A subpass input variable identified with an `InputAttachmentIndex` decoration of i reads from the input attachment indicated by `pInputAttachments`[i] member of `VkSubpassDescription`. If the subpass input variable is declared as an array of size N, it consumes N consecutive input attachments, starting with the index specified. There must not be more than one input variable with the same `InputAttachmentIndex` whether explicitly declared or implied by an array declaration. The number of available input attachment indices is given by the `maxPerStageDescriptorInputAttachments` member of the `VkPhysicalDeviceLimits` structure.

Variables identified with the `InputAttachmentIndex` must only be used by a fragment stage. The basic data type (floating-point, integer, unsigned integer) of the subpass input must match the basic format of the corresponding input attachment, or the values of subpass loads from these variables are undefined.

See Input Attachment for more details.

### 14.5. Shader Resource Interface

When a shader stage accesses buffer or image resources, as described in the Resource Descriptors section, the shader resource variables must be matched with the pipeline layout that is provided at pipeline creation time.

The set of shader resources that form the shader resource interface for a stage are the variables statically used by `OpEntryPoint` with the storage class of `Uniform`, `UniformConstant`, or `PushConstant`. For the fragment shader, this includes the fragment input attachment interface.

The shader resource interface consists of two sub-interfaces: the push constant interface and the descriptor set interface.

#### 14.5.1. Push Constant Interface

The shader variables defined with a storage class of `PushConstant` that are statically used by the shader entry points for the pipeline define the push constant interface. They must be:

- typed as `OpTypeStruct`,

- identified with a `Block` decoration, and

- laid out explicitly using the `Offset`, `ArrayStride`, and `MatrixStride` decorations as specified in Offset and Stride Assignment.

There must be no more than one push constant block statically used per shader entry point.

Each statically used member of a push constant block must be placed at an `Offset` such that the entire member is entirely contained within the VkPushConstantRange for each `OpEntryPoint` that uses it, and the `stageFlags` for that range must specify the appropriate VkShaderStageFlagBits for that stage. The `Offset` decoration for any member of a push constant block must not cause the space required for that member to extend outside the range [0, `maxPushConstantsSize`).

Any member of a push constant block that is declared as an array must only be accessed with dynamically uniform indices.

#### 14.5.2. Descriptor Set Interface

The descriptor set interface is comprised of the shader variables with the storage class of `StorageBuffer`, `Uniform` or `UniformConstant` (including the variables in the fragment input attachment interface) that are statically used by the shader entry points for the pipeline.

These variables must have `DescriptorSet` and `Binding` decorations specified, which are assigned and matched with the `VkDescriptorSetLayout` objects in the pipeline layout as described in DescriptorSet and Binding Assignment.

The `Image` `Format` of an `OpTypeImage` declaration must not be Unknown, for variables which are used for `OpImageRead`, `OpImageSparseRead`, or `OpImageWrite` operations, except under the following conditions:

- For `OpImageWrite`, if the `shaderStorageImageWriteWithoutFormat` feature is enabled and the shader module declares the `StorageImageWriteWithoutFormat` capability.

- For `OpImageRead` or `OpImageSparseRead`, if the `shaderStorageImageReadWithoutFormat` feature is enabled and the shader module declares the `StorageImageReadWithoutFormat` capability.

- For `OpImageRead`, if `Dim` is `SubpassData` (indicating a read from an input attachment).

The `Image` `Format` of an `OpTypeImage` declaration must not be Unknown, for variables which are used for `OpAtomic`* operations.

Variables identified with the `Uniform` storage class are used to access transparent buffer backed resources. Such variables must be:

- typed as `OpTypeStruct`, or an array of this type,

- identified with a `Block` or `BufferBlock` decoration, and

- laid out explicitly using the `Offset`, `ArrayStride`, and `MatrixStride` decorations as specified in Offset and Stride Assignment.

Variables identified with the `StorageBuffer` storage class are used to access transparent buffer backed resources. Such variables must be:

- typed as `OpTypeStruct`, or an array of this type,

- identified with a `Block` decoration, and

- laid out explicitly using the `Offset`, `ArrayStride`, and `MatrixStride` decorations as specified in Offset and Stride Assignment.

The `Offset` decoration for any member of a `Block`-decorated variable in the `Uniform` storage class must not cause the space required for that variable to extend outside the range [0, `maxUniformBufferRange`). The `Offset` decoration for any member of a `Block`-decorated variable in the `StorageBuffer` storage class must not cause the space required for that variable to extend outside the range [0, `maxStorageBufferRange`).

Variables identified with the `Uniform` storage class can also be used to access transparent descriptor set backed resources when the variable is assigned to a descriptor set layout binding with a `descriptorType` of `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT`. In this case the variable must be typed as `OpTypeStruct` and cannot be aggregated into arrays of that type. Further, the `Offset` decoration for any member of such a variable must not cause the space required for that variable to extend outside the range [0,`maxInlineUniformBlockSize`).

Variables identified with a storage class of `UniformConstant` and a decoration of `InputAttachmentIndex` must be declared as described in Fragment Input Attachment Interface.

SPIR-V variables decorated with a descriptor set and binding that identify a combined image sampler descriptor can have a type of `OpTypeImage`, `OpTypeSampler` (`Sampled`=1), or `OpTypeSampledImage`.

Arrays of any of these types can be indexed with constant integral expressions. The following features must be enabled and capabilities must be declared in order to index such arrays with dynamically uniform or non-uniform indices:

- Storage images (except storage texel buffers and input attachments):

  - Dynamically uniform: `shaderStorageImageArrayDynamicIndexing` and `StorageImageArrayDynamicIndexing`

  - Non-uniform: `shaderStorageImageArrayNonUniformIndexing` and `StorageImageArrayNonUniformIndexing`

- Storage texel buffers:

  - Dynamically uniform: `shaderStorageTexelBufferArrayDynamicIndexing` and `StorageTexelBufferArrayDynamicIndexing`

  - Non-uniform: `shaderStorageTexelBufferArrayNonUniformIndexing` and `StorageTexelBufferArrayNonUniformIndexing`

- Input attachments:

  - Dynamically uniform: `shaderInputAttachmentArrayDynamicIndexing` and `InputAttachmentArrayDynamicIndexing`

  - Non-uniform: `shaderInputAttachmentArrayNonUniformIndexing` and `InputAttachmentArrayNonUniformIndexing`

- Sampled images (except uniform texel buffers), samplers and combined image samplers:

  - Dynamically uniform: `shaderSampledImageArrayDynamicIndexing` and `SampledImageArrayDynamicIndexing`

  - Non-uniform: `shaderSampledImageArrayNonUniformIndexing` and `SampledImageArrayNonUniformIndexing`

- Uniform texel buffers:

  - Dynamically uniform: `shaderUniformTexelBufferArrayDynamicIndexing` and `UniformTexelBufferArrayDynamicIndexing`

  - Non-uniform: `shaderUniformTexelBufferArrayNonUniformIndexing` and `UniformTexelBufferArrayNonUniformIndexing`

- Uniform buffers:

  - Dynamically uniform: `shaderUniformBufferArrayDynamicIndexing` and `UniformBufferArrayDynamicIndexing`

  - Non-uniform: `shaderUniformBufferArrayNonUniformIndexing` and `UniformBufferArrayNonUniformIndexing`

- Storage buffers:

  - Dynamically uniform: `shaderStorageBufferArrayDynamicIndexing` and `StorageBufferArrayDynamicIndexing`

  - Non-uniform: `shaderStorageBufferArrayNonUniformIndexing` and `StorageBufferArrayNonUniformIndexing`

- Acceleration structures:

  - No additional capabilities needed.

If an instruction loads from or stores to a resource (including atomics and image instructions) and the resource descriptor being accessed is not dynamically uniform, then the corresponding non-uniform indexing feature must be enabled and the capability must be declared. If an instruction loads from or stores to a resource (including atomics and image instructions) and the resource descriptor being accessed is not uniform, then the corresponding dynamic indexing or non-uniform feature must be enabled and the capability must be declared.

If the combined image sampler enables sampler Y′CBCR conversion or samples a subsampled image, it must be indexed only by constant integral expressions when aggregated into arrays in shader code, irrespective of the `shaderSampledImageArrayDynamicIndexing` feature.

Table 19. Shader Resource and Descriptor Type Correspondence
Resource type | Descriptor Type
--- | ---
sampler | `VK_DESCRIPTOR_TYPE_SAMPLER` or `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`
sampled image | `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE` or `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`
storage image | `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE`
combined image sampler | `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`
uniform texel buffer | `VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER`
storage texel buffer | `VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER`
uniform buffer | `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER` or `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC`
storage buffer | `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER` or `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC`
input attachment | `VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT`
inline uniform block | `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT`
acceleration structure | `VK_DESCRIPTOR_TYPE_ACCELERATION_STRUCTURE_KHR`

Table 20. Shader Resource and Storage Class Correspondence
Resource type | Storage Class | Type | Decoration(s)1
--- | --- | --- | ---
sampler | `UniformConstant` | `OpTypeSampler` |
sampled image | `UniformConstant` | `OpTypeImage` (`Sampled`=1) |
storage image | `UniformConstant` | `OpTypeImage` (`Sampled`=2) |
combined image sampler | `UniformConstant` | `OpTypeSampledImage` `OpTypeImage` (`Sampled`=1) `OpTypeSampler` |
uniform texel buffer | `UniformConstant` | `OpTypeImage` (`Dim`=`Buffer`, `Sampled`=1) |
storage texel buffer | `UniformConstant` | `OpTypeImage` (`Dim`=`Buffer`, `Sampled`=2) |
uniform buffer | `Uniform` | `OpTypeStruct` | `Block`, `Offset`, (`ArrayStride`), (`MatrixStride`)
storage buffer | `Uniform` | `OpTypeStruct` | `BufferBlock`, `Offset`, (`ArrayStride`), (`MatrixStride`)
`StorageBuffer` | `Block`, `Offset`, (`ArrayStride`), (`MatrixStride`)
input attachment | `UniformConstant` | `OpTypeImage` (`Dim`=`SubpassData`, `Sampled`=2) | `InputAttachmentIndex`
inline uniform block | `Uniform` | `OpTypeStruct` | `Block`, `Offset`, (`ArrayStride`), (`MatrixStride`)
acceleration structure | `UniformConstant` | `OpTypeAccelerationStructureKHR` |

1

  in addition to `DescriptorSet` and `Binding`

#### 14.5.3. DescriptorSet and Binding Assignment

A variable decorated with a `DescriptorSet` decoration of s and a `Binding` decoration of b indicates that this variable is associated with the VkDescriptorSetLayoutBinding that has a `binding` equal to b in `pSetLayouts`[s] that was specified in VkPipelineLayoutCreateInfo.

`DescriptorSet` decoration values must be between zero and `maxBoundDescriptorSets` minus one, inclusive. `Binding` decoration values can be any 32-bit unsigned integer value, as described in Descriptor Set Layout. Each descriptor set has its own binding name space.

If the `Binding` decoration is used with an array, the entire array is assigned that binding value. The array must be a single-dimensional array and size of the array must be no larger than the number of descriptors in the binding. If the array is runtime-sized, then array elements greater than or equal to the size of that binding in the bound descriptor set must not be used. If the array is runtime-sized, the `runtimeDescriptorArray` feature must be enabled and the `RuntimeDescriptorArray` capability must be declared. The index of each element of the array is referred to as the arrayElement. For the purposes of interface matching and descriptor set operations, if a resource variable is not an array, it is treated as if it has an arrayElement of zero.

There is a limit on the number of resources of each type that can be accessed by a pipeline stage as shown in Shader Resource Limits. The “Resources Per Stage” column gives the limit on the number each type of resource that can be statically used for an entry point in any given stage in a pipeline. The “Resource Types” column lists which resource types are counted against the limit. Some resource types count against multiple limits.

The pipeline layout may include descriptor sets and bindings which are not referenced by any variables statically used by the entry points for the shader stages in the binding’s `stageFlags`.

However, if a variable assigned to a given `DescriptorSet` and `Binding` is statically used by the entry point for a shader stage, the pipeline layout must contain a descriptor set layout binding in that descriptor set layout and for that binding number, and that binding’s `stageFlags` must include the appropriate VkShaderStageFlagBits for that stage. The variable must be of a valid resource type determined by its SPIR-V type and storage class, as defined in Shader Resource and Storage Class Correspondence. The descriptor set layout binding must be of a corresponding descriptor type, as defined in Shader Resource and Descriptor Type Correspondence.

| Note There are no limits on the number of shader variables that can have overlapping set and binding values in a shader; but which resources are statically used has an impact. If any shader variable identifying a resource is statically used in a shader, then the underlying descriptor bound at the declared set and binding must support the declared type in the shader when the shader executes. If multiple shader variables are declared with the same set and binding values, and with the same underlying descriptor type, they can all be statically used within the same shader. However, accesses are not automatically synchronized, and `Aliased` decorations should be used to avoid data hazards (see section 2.18.2 Aliasing in the SPIR-V specification). If multiple shader variables with the same set and binding values are declared in a single shader, but with different declared types, where any of those are not supported by the relevant bound descriptor, that shader can only be executed if the variables with the unsupported type are not statically used. A noteworthy example of using multiple statically-used shader variables sharing the same descriptor set and binding values is a descriptor of type `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER` that has multiple corresponding shader variables in the `UniformConstant` storage class, where some could be `OpTypeImage`, some could be `OpTypeSampler` (`Sampled`=1), and some could be `OpTypeSampledImage`.

Table 21. Shader Resource Limits
Resources per Stage | Resource Types
--- | ---
`maxPerStageDescriptorSamplers` or `maxPerStageDescriptorUpdateAfterBindSamplers` | sampler
combined image sampler
`maxPerStageDescriptorSampledImages` or `maxPerStageDescriptorUpdateAfterBindSampledImages` | sampled image
combined image sampler
uniform texel buffer
`maxPerStageDescriptorStorageImages` or `maxPerStageDescriptorUpdateAfterBindStorageImages` | storage image
storage texel buffer
`maxPerStageDescriptorUniformBuffers` or `maxPerStageDescriptorUpdateAfterBindUniformBuffers` | uniform buffer
uniform buffer dynamic
`maxPerStageDescriptorStorageBuffers` or `maxPerStageDescriptorUpdateAfterBindStorageBuffers` | storage buffer
storage buffer dynamic
`maxPerStageDescriptorInputAttachments` or `maxPerStageDescriptorUpdateAfterBindInputAttachments` | input attachment1
`maxPerStageDescriptorInlineUniformBlocks` or `maxPerStageDescriptorUpdateAfterBindInlineUniformBlocks` | inline uniform block
`maxDescriptorSetAccelerationStructures` | acceleration structure

1

  Input attachments can only be used in the fragment shader stage

#### 14.5.4. Offset and Stride Assignment

All variables with a storage class of `Uniform`, `StorageBuffer`, or `PushConstant` must be explicitly laid out using the `Offset`, `ArrayStride`, and `MatrixStride` decorations.

| Note The numeric order of `Offset` decorations does not need to follow member declaration order.

Alignment Requirements

There are different alignment requirements depending on the specific resources and on the features enabled on the device.

The scalar alignment of the type of an `OpTypeStruct` member is defined recursively as follows:

- A scalar of size N has a scalar alignment of N.

- A vector or matrix type has a scalar alignment equal to that of its component type.

- An array type has a scalar alignment equal to that of its element type.

- A structure has a scalar alignment equal to the largest scalar alignment of any of its members.

The base alignment of the type of an `OpTypeStruct` member is defined recursively as follows:

- A scalar has a base alignment equal to its scalar alignment.

- A two-component vector has a base alignment equal to twice its scalar alignment.

- A three- or four-component vector has a base alignment equal to four times its scalar alignment.

- An array has a base alignment equal to the base alignment of its element type.

- A structure has a base alignment equal to the largest base alignment of any of its members.

- A row-major matrix of C columns has a base alignment equal to the base alignment of a vector of C matrix components.

- A column-major matrix has a base alignment equal to the base alignment of the matrix column type.

The extended alignment of the type of an `OpTypeStruct` member is similarly defined as follows:

- A scalar, vector or matrix type has an extended alignment equal to its base alignment.

- An array or structure type has an extended alignment equal to the largest extended alignment of any of its members, rounded up to a multiple of 16.

A member is defined to improperly straddle if either of the following are true:

- It is a vector with total size less than or equal to 16 bytes, and has `Offset` decorations placing its first byte at F and its last byte at L, where floor(F / 16) != floor(L / 16).

- It is a vector with total size greater than 16 bytes and has its `Offset` decorations placing its first byte at a non-integer multiple of 16.

Standard Buffer Layout

Every member of an `OpTypeStruct` with storage class of `Uniform`, `StorageBuffer`, or `PushConstant` must be aligned according to the first matching rule as follows:

1. If the `scalarBlockLayout` feature is enabled on the device then every member must be aligned according to its scalar alignment.

2. All vectors must be aligned according to their scalar alignment.

3. If the `uniformBufferStandardLayout` feature is not enabled on the device, then any member of an `OpTypeStruct` with a storage class of `Uniform` and a decoration of `Block` must be aligned according to its extended alignment.

4. Every other member must be aligned according to its base alignment.

| Note Even if scalar alignment is supported, it is generally more performant to use the base alignment.

The memory layout must obey the following rules:

- The `Offset` decoration of any member must be a multiple of its alignment.

- Any `ArrayStride` or `MatrixStride` decoration must be a multiple of the alignment of the array or matrix as defined above.

Unless the `scalarBlockLayout` feature is enabled on the device:

- Vectors must not improperly straddle, as defined above.

- The `Offset` decoration of a member must not place it between the end of a structure or an array and the next multiple of the alignment of that structure or array.

| Note The std430 layout in GLSL satisfies these rules for types using the base alignment. The std140 layout satisfies the rules for types using the extended alignment.

### 14.6. Built-In Variables

Built-in variables are accessed in shaders by declaring a variable decorated with a `BuiltIn` SPIR-V decoration. The meaning of each `BuiltIn` decoration is as follows. In the remainder of this section, the name of a built-in is used interchangeably with a term equivalent to a variable decorated with that particular built-in. Built-ins that represent integer values can be declared as either signed or unsigned 32-bit integers.

As mentioned above, some inputs and outputs have an additional level of arrayness relative to other shader inputs and outputs. This level of arrayness is not included in the type descriptions below, but must be included when declaring the built-in.

`BaryCoordNV`

  The `BaryCoordNV` decoration can be used to decorate a fragment shader input variable. This variable will contain a three-component floating-point vector with barycentric weights that indicate the location of the fragment relative to the screen-space locations of vertices of its primitive, obtained using perspective interpolation.

  The `BaryCoordNV` decoration must be used only within fragment shaders.

  The variable decorated with `BaryCoordNV` must be declared using the `Input` storage class.

  The variable decorated with `BaryCoordNV` must be declared as three-component vector of 32-bit floating-point values.

`BaryCoordNoPerspAMD`

  The `BaryCoordNoPerspAMD` decoration can be used to decorate a fragment shader input variable. This variable will contain the (I,J) pair of the barycentric coordinates corresponding to the fragment evaluated using linear interpolation at the fragment’s center. The K coordinate of the barycentric coordinates can be derived given the identity I + J + K = 1.0.

`BaryCoordNoPerspNV`

  The `BaryCoordNoPerspNV` decoration can be used to decorate a fragment shader input variable. This variable will contain a three-component floating-point vector with barycentric weights that indicate the location of the fragment relative to the screen-space locations of vertices of its primitive, obtained using linear interpolation.

  The `BaryCoordNoPerspNV` decoration must be used only within fragment shaders.

  The variable decorated with `BaryCoordNoPerspNV` must be declared using the `Input` storage class.

  The variable decorated with `BaryCoordNoPerspNV` must be declared as three-component vector of 32-bit floating-point values.

`BaryCoordNoPerspCentroidAMD`

  The `BaryCoordNoPerspCentroidAMD` decoration can be used to decorate a fragment shader input variable. This variable will contain the (I,J) pair of the barycentric coordinates corresponding to the fragment evaluated using linear interpolation at the centroid. The K coordinate of the barycentric coordinates can be derived given the identity I + J + K = 1.0.

`BaryCoordNoPerspSampleAMD`

  The `BaryCoordNoPerspCentroidAMD` decoration can be used to decorate a fragment shader input variable. This variable will contain the (I,J) pair of the barycentric coordinates corresponding to the fragment evaluated using linear interpolation at each covered sample. The K coordinate of the barycentric coordinates can be derived given the identity I + J + K = 1.0.

`BaryCoordPullModelAMD`

  The `BaryCoordPullModelAMD` decoration can be used to decorate a fragment shader input variable. This variable will contain (1/W, 1/I, 1/J) evaluated at the fragment center and can be used to calculate gradients and then interpolate I, J, and W at any desired sample location.

`BaryCoordSmoothAMD`

  The `BaryCoordSmoothAMD` decoration can be used to decorate a fragment shader input variable. This variable will contain the (I,J) pair of the barycentric coordinates corresponding to the fragment evaluated using perspective interpolation at the fragment’s center. The K coordinate of the barycentric coordinates can be derived given the identity I + J + K = 1.0.

`BaryCoordSmoothCentroidAMD`

  The `BaryCoordSmoothCentroidAMD` decoration can be used to decorate a fragment shader input variable. This variable will contain the (I,J) pair of the barycentric coordinates corresponding to the fragment evaluated using perspective interpolation at the centroid. The K coordinate of the barycentric coordinates can be derived given the identity I + J + K = 1.0.

`BaryCoordSmoothSampleAMD`

  The `BaryCoordSmoothCentroidAMD` decoration can be used to decorate a fragment shader input variable. This variable will contain the (I,J) pair of the barycentric coordinates corresponding to the fragment evaluated using perspective interpolation at each covered sample. The K coordinate of the barycentric coordinates can be derived given the identity I + J + K = 1.0.

`BaseInstance`

  Decorating a variable with the `BaseInstance` built-in will make that variable contain the integer value corresponding to the first instance that was passed to the command that invoked the current vertex shader invocation. `BaseInstance` is the `firstInstance` parameter to a direct drawing command or the `firstInstance` member of a structure consumed by an indirect drawing command.

  The `BaseInstance` decoration must be used only within vertex shaders.

  The variable decorated with BaseInstance must be declared using the input storage class.

  The variable decorated with BaseInstance must be declared as a scalar 32-bit integer.

`BaseVertex`

  Decorating a variable with the `BaseVertex` built-in will make that variable contain the integer value corresponding to the first vertex or vertex offset that was passed to the command that invoked the current vertex shader invocation. For non-indexed drawing commands, this variable is the `firstVertex` parameter to a direct drawing command or the `firstVertex` member of the structure consumed by an indirect drawing command. For indexed drawing commands, this variable is the `vertexOffset` parameter to a direct drawing command or the `vertexOffset` member of the structure consumed by an indirect drawing command.

  The `BaseVertex` decoration must be used only within vertex shaders.

  The variable decorated with `BaseVertex` must be declared using the input storage class.

  The variable decorated with `BaseVertex` must be declared as a scalar 32-bit integer.

`ClipDistance`

  Decorating a variable with the `ClipDistance` built-in decoration will make that variable contain the mechanism for controlling user clipping. `ClipDistance` is an array such that the ith element of the array specifies the clip distance for plane i. A clip distance of 0 means the vertex is on the plane, a positive distance means the vertex is inside the clip half-space, and a negative distance means the point is outside the clip half-space.

  The `ClipDistance` decoration must be used only within mesh, vertex, fragment, tessellation control, tessellation evaluation, and geometry shaders.

  In mesh or vertex shaders, any variable decorated with `ClipDistance` must be declared using the `Output` storage class.

  In fragment shaders, any variable decorated with `ClipDistance` must be declared using the `Input` storage class.

  In tessellation control, tessellation evaluation, or geometry shaders, any variable decorated with `ClipDistance` must not be in a storage class other than `Input` or `Output`.

  Any variable decorated with `ClipDistance` must be declared as an array of 32-bit floating-point values.

| Note The array variable decorated with `ClipDistance` is explicitly sized by the shader.

| Note In the last vertex processing stage, these values will be linearly interpolated across the primitive and the portion of the primitive with interpolated distances less than 0 will be considered outside the clip volume. If `ClipDistance` is then used by a fragment shader, `ClipDistance` contains these linearly interpolated values.

`ClipDistancePerViewNV`

  Decorating a variable with the `ClipDistancePerViewNV` built-in decoration will make that variable contain the per-view clip distances. The per-view clip distances have the same semantics as `ClipDistance`.

  The `ClipDistancePerViewNV` must be used only within mesh shaders.

  Any variable decorated with `ClipDistancePerViewNV` must be declared using the `Output` storage class, and must also be decorated with the `PerViewNV` decoration.

  Any variable decorated with `ClipDistancePerViewNV` must be declared as a two-dimensional array of 32-bit floating-point values.

`CullDistance`

  Decorating a variable with the `CullDistance` built-in decoration will make that variable contain the mechanism for controlling user culling. If any member of this array is assigned a negative value for all vertices belonging to a primitive, then the primitive is discarded before rasterization.

  The `CullDistance` decoration must be used only within mesh, vertex, fragment, tessellation control, tessellation evaluation, and geometry shaders.

  In mesh or vertex shaders, any variable decorated with `CullDistance` must be declared using the `Output` storage class.

  In fragment shaders, any variable decorated with `CullDistance` must be declared using the `Input` storage class.

  In tessellation control, tessellation evaluation, or geometry shaders, any variable decorated with `CullDistance` must not be declared in a storage class other than input or output.

  Any variable decorated with `CullDistance` must be declared as an array of 32-bit floating-point values.

| Note In fragment shaders, the values of the `CullDistance` array are linearly interpolated across each primitive.

| Note If `CullDistance` decorates an input variable, that variable will contain the corresponding value from the `CullDistance` decorated output variable from the previous shader stage.

`CullDistancePerViewNV`

  Decorating a variable with the `CullDistancePerViewNV` built-in decoration will make that variable contain the per-view cull distances. The per-view clip distances have the same semantics as `CullDistance`.

  The `CullDistancePerViewNV` must be used only within mesh shaders.

  Any variable decorated with `CullDistancePerViewNV` must be declared using the `Output` storage class, and must also be decorated with the `PerViewNV` decoration.

  Any variable decorated with `CullDistancePerViewNV` must be declared as a two-dimensional array of 32-bit floating-point values.

`DeviceIndex`

  The `DeviceIndex` decoration can be applied to a shader input which will be filled with the device index of the physical device that is executing the current shader invocation. This value will be in the range \([0,max(1,physicalDeviceCount))\), where physicalDeviceCount is the `physicalDeviceCount` member of VkDeviceGroupDeviceCreateInfo.

  The `DeviceIndex` decoration can be used in any shader.

  The variable decorated with `DeviceIndex` must be declared using the `Input` storage class.

  The variable decorated with `DeviceIndex` must be declared as a scalar 32-bit integer.

`DrawIndex`

  Decorating a variable with the `DrawIndex` built-in will make that variable contain the integer value corresponding to the zero-based index of the drawing command that invoked the current task, mesh, or vertex shader invocation. For indirect drawing commands, `DrawIndex` begins at zero and increments by one for each draw command executed. The number of draw commands is given by the `drawCount` parameter. For direct drawing commands, `DrawIndex` is always zero. `DrawIndex` is dynamically uniform.

  The `DrawIndex` decoration must be used only within task, mesh or vertex shaders.

  The variable decorated with `DrawIndex` must be declared using the input storage class.

  The variable decorated with `DrawIndex` must be declared as a scalar 32-bit integer.

  When task or mesh shaders are used, only the first active stage will have proper access to the variable, other stages will have undefined values.

`FragCoord`

  Decorating a variable with the `FragCoord` built-in decoration will make that variable contain the framebuffer coordinate \((x,y,z,\frac{1}{w})\) of the fragment being processed. The (x,y) coordinate (0,0) is the upper left corner of the upper left pixel in the framebuffer.

  When Sample Shading is enabled, the x and y components of `FragCoord` reflect the location of one of the samples corresponding to the shader invocation.

  Otherwise, the x and y components of `FragCoord` reflect the location of the center of the fragment.

  The z component of `FragCoord` is the interpolated depth value of the primitive.

  The w component is the interpolated \(\frac{1}{w}\).

  The `FragCoord` decoration must be used only within fragment shaders.

  The variable decorated with `FragCoord` must be declared using the `Input` storage class.

  The `Centroid` interpolation decoration is ignored, but allowed, on `FragCoord`.

  The variable decorated with `FragCoord` must be declared as a four-component vector of 32-bit floating-point values.

`FragDepth`

  To have a shader supply a fragment-depth value, the shader must declare the `DepthReplacing` execution mode. Such a shader’s fragment-depth value will come from the variable decorated with the `FragDepth` built-in decoration.

  This value will be used for any subsequent depth testing performed by the implementation or writes to the depth attachment.

  The `FragDepth` decoration must be used only within fragment shaders.

  The variable decorated with `FragDepth` must be declared using the `Output` storage class.

  The variable decorated with `FragDepth` must be declared as a scalar 32-bit floating-point value.

`FragInvocationCountEXT`

  Decorating a variable with the `FragInvocationCountEXT` built-in decoration will make that variable contain the maximum number of fragment shader invocations for the fragment, as determined by `minSampleShading`.

  The `FragInvocationCountEXT` decoration must be used only within fragment shaders and the `FragmentDensityEXT` capability must be declared.

  If Sample Shading is not enabled, `FragInvocationCountEXT` will be filled with a value of 1.

  The variable decorated with `FragInvocationCountEXT` must be declared using the `Input` storage class.

  The variable decorated with `FragInvocationCountEXT` must be declared as a scalar 32-bit integer.

`FragSizeEXT`

  Decorating a variable with the `FragSizeEXT` built-in decoration will make that variable contain the dimensions in pixels of the area that the fragment covers for that invocation.

  The `FragSizeEXT` decoration must be used only within fragment shaders and the `FragmentDensityEXT` capability must be declared.

  If fragment density map is not enabled, `FragSizeEXT` will be filled with a value of (1,1).

  The variable decorated with `FragSizeEXT` must be declared using the `Input` storage class.

  The variable decorated with `FragSizeEXT` must be declared as a two-component vector of 32-bit integers.

`FragStencilRefEXT`

  Decorating a variable with the `FragStencilRefEXT` built-in decoration will make that variable contain the new stencil reference value for all samples covered by the fragment. This value will be used as the stencil reference value used in stencil testing.

  To write to `FragStencilRefEXT`, a shader must declare the `StencilRefReplacingEXT` execution mode. If a shader declares the `StencilRefReplacingEXT` execution mode and there is an execution path through the shader that does not set `FragStencilRefEXT`, then the fragment’s stencil reference value is undefined for executions of the shader that take that path.

  The `FragStencilRefEXT` decoration must be used only within fragment shaders.

  The variable decorated with `FragStencilRefEXT` must be declared using the `Output` storage class.

  The variable decorated with `FragStencilRefEXT` must be declared as a scalar integer value. Only the least significant s bits of the integer value of the variable decorated with `FragStencilRefEXT` are considered for stencil testing, where s is the number of bits in the stencil framebuffer attachment, and higher order bits are discarded.

`FragmentSizeNV`

  Decorating a variable with the `FragmentSizeNV` built-in decoration will make that variable contain the width and height of the fragment.

  The `FragmentSizeNV` decoration must be used only within fragment shaders.

  The variable decorated with `FragmentSizeNV` must be declared using the `Input` storage class.

  The variable decorated with `FragmentSizeNV` must be declared as a two-component vector of 32-bit integers.

`FrontFacing`

  Decorating a variable with the `FrontFacing` built-in decoration will make that variable contain whether the fragment is front or back facing. This variable is non-zero if the current fragment is considered to be part of a front-facing polygon primitive or of a non-polygon primitive and is zero if the fragment is considered to be part of a back-facing polygon primitive.

  The `FrontFacing` decoration must be used only within fragment shaders.

  The variable decorated with `FrontFacing` must be declared using the `Input` storage class.

  The variable decorated with `FrontFacing` must be declared as a boolean.

`FullyCoveredEXT`

  Decorating a variable with the `FullyCoveredEXT` built-in decoration will make that variable indicate whether the fragment area is fully covered by the generating primitive. This variable is non-zero if conservative rasterization is enabled and the current fragment area is fully covered by the generating primitive, and is zero if the fragment is not covered or partially covered, or conservative rasterization is disabled.

  The `FullyCoveredEXT` decoration must be used only within fragment shaders and the `FragmentFullyCoveredEXT` capability must be declared.

  The variable decorated with `FullyCoveredEXT` must be declared using the `Input` storage class.

  The variable decorated with `FullyCoveredEXT` must be declared as a boolean.

  If the implementation supports `VkPhysicalDeviceConservativeRasterizationPropertiesEXT`::`conservativeRasterizationPostDepthCoverage` and the `PostDepthCoverage` execution mode is specified the `SampleMask` built-in input variable will reflect the coverage after the early per-fragment depth and stencil tests are applied. If `VkPhysicalDeviceConservativeRasterizationPropertiesEXT`::`conservativeRasterizationPostDepthCoverage` is not supported the `PostDepthCoverage` execution mode must not be specified.

`GlobalInvocationId`

  Decorating a variable with the `GlobalInvocationId` built-in decoration will make that variable contain the location of the current invocation within the global workgroup. Each component is equal to the index of the local workgroup multiplied by the size of the local workgroup plus `LocalInvocationId`.

  The `GlobalInvocationId` decoration must be used only within task, mesh, or compute shaders.

  The variable decorated with `GlobalInvocationId` must be declared using the `Input` storage class.

  The variable decorated with `GlobalInvocationId` must be declared as a three-component vector of 32-bit integers.

`HelperInvocation`

  Decorating a variable with the `HelperInvocation` built-in decoration will make that variable contain whether the current invocation is a helper invocation. This variable is non-zero if the current fragment being shaded is a helper invocation and zero otherwise. A helper invocation is an invocation of the shader that is produced to satisfy internal requirements such as the generation of derivatives.

  The `HelperInvocation` decoration must be used only within fragment shaders.

  The variable decorated with `HelperInvocation` must be declared using the `Input` storage class.

  The variable decorated with `HelperInvocation` must be declared as a boolean.

| Note It is very likely that a helper invocation will have a value of `SampleMask` fragment shader input value that is zero.

`HitKindKHR`

  A variable decorated with the `HitKindKHR` decoration will describe the intersection that triggered the execution of the current shader. The values are determined by the intersection shader. For user-defined intersection shaders this is the value that was passed to the “Hit Kind” operand of `OpReportIntersectionKHR`. For triangle intersection candidates, this will be one of `HitKindFrontFacingTriangleKHR` or `HitKindBackFacingTriangleKHR`.

  The `HitKindKHR` decoration must only be used in any-hit and closest hit shaders.

  Any variable decorated with `HitKindKHR` must be declared using the `Input` storage class.

  Any variable decorated with `HitKindKHR` must be declared as a scalar 32-bit integer.

`HitTNV`

  A variable decorated with the `HitTNV` decoration is equivalent to a variable decorated with the `RayTmaxKHR` decoration.

  The `HitTNV` decoration must only be used in any-hit and closest hit shaders.

  Any variable decorated with `HitTNV` must be declared using the `Input` storage class.

  Any variable decorated with `HitTNV` must be declared as a scalar 32-bit floating-point value.

`IncomingRayFlagsKHR`

  A variable with the `IncomingRayFlagsKHR` decoration will contain the ray flags passed in to the trace call that invoked this particular shader.

  The `IncomingRayFlagsKHR` decoration must only be used in the intersection, any-hit, closest hit, and miss shaders.

  Any variable decorated with `IncomingRayFlagsKHR` must be declared using the `Input` storage class.

  Any variable decorated with `IncomingRayFlagsKHR` must be declared as a scalar 32-bit integer.

`InstanceCustomIndexKHR`

  A variable decorated with the `InstanceCustomIndexKHR` decoration will contain the application-defined value of the instance that intersects the current ray. Only the lower 24 bits are valid, the upper 8 bits will be ignored.

  The `InstanceCustomIndexKHR` decoration must only be used in the intersection, any-hit, and closest hit shaders.

  Any variable decorated with `InstanceCustomIndexKHR` must be declared using the `Input` storage class.

  Any variable decorated with `InstanceCustomIndexKHR` must be declared as a scalar 32-bit integer.

`InstanceId`

  Decorating a variable in an intersection, any-hit, or closest hit shader with the `InstanceId` decoration will make that variable contain the index of the instance that intersects the current ray.

  The `InstanceId` decoration must be used only within intersection, any-hit, or closest hit shaders.

  The variable decorated with `InstanceId` must be declared using the `Input` storage class.

  The variable decorated with `InstanceId` must be declared as a scalar 32-bit integer.

`InvocationId`

  Decorating a variable with the `InvocationId` built-in decoration will make that variable contain the index of the current shader invocation in a geometry shader, or the index of the output patch vertex in a tessellation control shader.

  In a geometry shader, the index of the current shader invocation ranges from zero to the number of instances declared in the shader minus one. If the instance count of the geometry shader is one or is not specified, then `InvocationId` will be zero.

  The `InvocationId` decoration must be used only within tessellation control and geometry shaders.

  The variable decorated with `InvocationId` must be declared using the `Input` storage class.

  The variable decorated with `InvocationId` must be declared as a scalar 32-bit integer.

`InvocationsPerPixelNV`

  Decorating a variable with the `InvocationsPerPixelNV` built-in decoration will make that variable contain the maximum number of fragment shader invocations per pixel, as derived from the effective shading rate for the fragment. If a primitive does not fully cover a pixel, the number of fragment shader invocations for that pixel may be less than the value of `InvocationsPerPixelNV`. If the shading rate indicates a fragment covering multiple pixels, then `InvocationsPerPixelNV` will be one.

  The `InvocationsPerPixelNV` decoration must be used only within fragment shaders.

  The variable decorated with `InvocationsPerPixelNV` must be declared using the `Input` storage class.

  The variable decorated with `InvocationsPerPixelNV` must be declared as a scalar 32-bit integer.

`InstanceIndex`

  Decorating a variable in a vertex shader with the `InstanceIndex` built-in decoration will make that variable contain the index of the instance that is being processed by the current vertex shader invocation. `InstanceIndex` begins at the `firstInstance` parameter to vkCmdDraw or vkCmdDrawIndexed or at the `firstInstance` member of a structure consumed by vkCmdDrawIndirect or vkCmdDrawIndexedIndirect.

  The `InstanceIndex` decoration must be used only within vertex shaders.

  The variable decorated with `InstanceIndex` must be declared using the `Input` storage class.

  The variable decorated with `InstanceIndex` must be declared as a scalar 32-bit integer.

`LaunchIDKHR`

  A variable decorated with the `LaunchIDKHR` decoration will specify the index of the work item being process. One work item is generated for each of the `width` × `height` × `depth` items dispatched by a vkCmdTraceRaysKHR command. All shader invocations inherit the same value for variables decorated with `LaunchIDKHR`.

  The `LaunchIDKHR` decoration must only be used within the ray generation, intersection, any-hit, closest hit, and miss shaders.

  Any variable decorated with `LaunchIDKHR` must be declared using the `Input` storage class.

  Any variable decorated with `LaunchIDKHR` must be declared as a three-component vector of 32-bit integer values.

`LaunchSizeKHR`

  A variable decorated with the `LaunchSizeKHR` decoration will contain the `width`, `height`, and `depth` dimensions passed to the vkCmdTraceRaysKHR command that initiated this shader execution. The `width` is in the first component, the `height` is in the second component, and the `depth` is in the third component.

  The `LaunchSizeKHR` decoration must only be used within ray generation, intersection, any-hit, closest hit, and miss shaders.

  Any variable decorated with `LaunchSizeKHR` must be declared using the `Input` storage class.

  Any variable decorated with `LaunchSizeKHR` must be declared as a three-component vector of 32-bit integer values.

`Layer`

  Decorating a variable with the `Layer` built-in decoration will make that variable contain the select layer of a multi-layer framebuffer attachment.

  In a mesh, vertex, tessellation evaluation, or geometry shader, any variable decorated with `Layer` can be written with the framebuffer layer index to which the primitive produced by that shader will be directed.

  The last active vertex processing stage (in pipeline order) controls the `Layer` that is used. Outputs in previous shader stages are not used, even if the last stage fails to write the `Layer`.

  If the last active vertex processing stage shader entry point’s interface does not include a variable decorated with `Layer`, then the first layer is used. If a vertex processing stage shader entry point’s interface includes a variable decorated with `Layer`, it must write the same value to `Layer` for all output vertices of a given primitive. If the `Layer` value is less than 0 or greater than or equal to the number of layers in the framebuffer, then primitives may still be rasterized, fragment shaders may be executed, and the framebuffer values for all layers are undefined.

  The `Layer` decoration must be used only within mesh, vertex, tessellation evaluation, geometry, and fragment shaders. If the shaderOutputLayer feature is not enabled then the `Layer` decoration must be used only with geometry, and fragment shaders.

  In a mesh, vertex, tessellation evaluation, or geometry shader, any variable decorated with `Layer` must be declared using the `Output` storage class. If such a variable is also decorated with `ViewportRelativeNV`, then the `ViewportIndex` is added to the layer that is used for rendering and that is made available in the fragment shader. If the shader writes to a variable decorated `ViewportMaskNV`, then the layer selected has a different value for each viewport a primitive is rendered to.

  In a fragment shader, a variable decorated with `Layer` contains the layer index of the primitive that the fragment invocation belongs to.

  In a fragment shader, any variable decorated with `Layer` must be declared using the `Input` storage class.

  Any variable decorated with `Layer` must be declared as a scalar 32-bit integer.

`LayerPerViewNV`

  Decorating a variable with the `LayerPerViewNV` built-in decoration will make that variable contain the per-view layer information. The per-view layer has the same semantics as `Layer`, for each view.

  The `LayerPerViewNV` must only be used within mesh shaders.

  Any variable decorated with `LayerPerViewNV` must be declared using the `Output` storage class, and must also be decorated with the `PerViewNV` decoration.

  Any variable decorated with `LayerPerViewNV` must be declared as an array of scalar 32-bit integer values.

`LocalInvocationId`

  Decorating a variable with the `LocalInvocationId` built-in decoration will make that variable contain the location of the current task, mesh, or compute shader invocation within the local workgroup. Each component ranges from zero through to the size of the workgroup in that dimension minus one.

  The `LocalInvocationId` decoration must be used only within task, mesh, or compute shaders.

  The variable decorated with `LocalInvocationId` must be declared using the `Input` storage class.

  The variable decorated with `LocalInvocationId` must be declared as a three-component vector of 32-bit integers.

| Note If the size of the workgroup in a particular dimension is one, then the `LocalInvocationId` in that dimension will be zero. If the workgroup is effectively two-dimensional, then `LocalInvocationId.z` will be zero. If the workgroup is effectively one-dimensional, then both `LocalInvocationId.y` and `LocalInvocationId.z` will be zero.

`LocalInvocationIndex`

  Decorating a variable with the `LocalInvocationIndex` built-in decoration will make that variable contain a one-dimensional representation of `LocalInvocationId`. This is computed as:

      LocalInvocationIndex =
          LocalInvocationId.z * WorkgroupSize.x * WorkgroupSize.y +
          LocalInvocationId.y * WorkgroupSize.x +
          LocalInvocationId.x;

  The `LocalInvocationIndex` decoration must be used only within task, mesh, or compute shaders.

  The variable decorated with `LocalInvocationIndex` must be declared using the `Input` storage class.

  The variable decorated with `LocalInvocationIndex` must be declared as a scalar 32-bit integer.

`MeshViewCountNV`

  Decorating a variable with the `MeshViewCountNV` built-in decoration will make that variable contain the number of views processed by the current mesh or task shader invocations.

  The `MeshViewCountNV` decoration must only be used in task and mesh shaders.

  Any variable decorated with `MeshViewCountNV` must be declared using the `Input` storage class.

  Any variable decorated with `MeshViewCountNV` must be declared as a scalar 32-bit integer.

`MeshViewIndicesNV`

  Decorating a variable with the `MeshViewIndicesNV` built-in decoration will make that variable contain the mesh view indices. The mesh view indices is an array of values where each element holds the view number of one of the views being processed by the current mesh or task shader invocations. The array elements with indices great than or equal to `MeshViewCountNV` are undefined. If the value of `MeshViewIndicesNV`[i] is j, then any outputs decorated with `PerViewNV` will take on the value of array element i when processing primitives for view index j.

  The `MeshViewIndicesNV` decoration must only be used in task and mesh shaders.

  Any variable decorated with `MeshViewIndicesNV` must be declared using the `Input` storage class.

  Any variable decorated with `MeshViewIndicesNV` must be declared as an array of scalar 32-bit integers.

`NumSubgroups`

  Decorating a variable with the `NumSubgroups` built-in decoration will make that variable contain the number of subgroups in the local workgroup.

  The `NumSubgroups` decoration must be used only within task, mesh, or compute shaders.

  The variable decorated with `NumSubgroups` must be declared using the `Input` storage class.

  The object decorated with `NumSubgroups` must be declared as a scalar 32-bit integer.

`NumWorkgroups`

  Decorating a variable with the `NumWorkgroups` built-in decoration will make that variable contain the number of local workgroups that are part of the dispatch that the invocation belongs to. Each component is equal to the values of the workgroup count parameters passed into the dispatch commands.

  The `NumWorkgroups` decoration must be used only within compute shaders.

  The variable decorated with `NumWorkgroups` must be declared using the `Input` storage class.

  The variable decorated with `NumWorkgroups` must be declared as a three-component vector of 32-bit integers.

`ObjectRayDirectionKHR`

  A variable decorated with the `ObjectRayDirectionKHR` decoration will specify the direction of the ray being processed, in object space.

  The `ObjectRayDirectionKHR` decoration must only be used within intersection, any-hit, and closest hit shaders.

  Any variable decorated with `ObjectRayDirectionKHR` must be declared using the `Input` storage class.

  Any variable decorated with `ObjectRayDirectionKHR` must be declared as a three-component vector of 32-bit floating-point values.

`ObjectRayOriginKHR`

  A variable decorated with the `ObjectRayOriginKHR` decoration will specify the origin of the ray being processed, in object space.

  The `ObjectRayOriginKHR` decoration must only be used within intersection, any-hit, and closest hit shaders.

  Any variable decorated with `ObjectRayOriginKHR` must be declared using the `Input` storage class.

  Any variable decorated with `ObjectRayOriginKHR` must be declared as a three-component vector of 32-bit floating-point values.

`ObjectToWorldKHR`

  A variable decorated with the `ObjectToWorldKHR` decoration will contain the current object-to-world transformation matrix, which is determined by the instance of the current intersection.

  The `ObjectToWorldKHR` decoration must only be used within intersection, any-hit, and closest hit shaders.

  Any variable decorated with `ObjectToWorldKHR` must be declared using the `Input` storage class.

  Any variable decorated with `ObjectToWorldKHR` must be declared as a matrix with four columns of three-component vectors of 32-bit floating-point values.

`PatchVertices`

  Decorating a variable with the `PatchVertices` built-in decoration will make that variable contain the number of vertices in the input patch being processed by the shader. A single tessellation control or tessellation evaluation shader can read patches of differing sizes, so the value of the `PatchVertices` variable may differ between patches.

  The `PatchVertices` decoration must be used only within tessellation control and tessellation evaluation shaders.

  The variable decorated with `PatchVertices` must be declared using the `Input` storage class.

  The variable decorated with `PatchVertices` must be declared as a scalar 32-bit integer.

`PointCoord`

  Decorating a variable with the `PointCoord` built-in decoration will make that variable contain the coordinate of the current fragment within the point being rasterized, normalized to the size of the point with origin in the upper left corner of the point, as described in Basic Point Rasterization. If the primitive the fragment shader invocation belongs to is not a point, then the variable decorated with `PointCoord` contains an undefined value.

  The `PointCoord` decoration must be used only within fragment shaders.

  The variable decorated with `PointCoord` must be declared using the `Input` storage class.

  The variable decorated with `PointCoord` must be declared as two-component vector of 32-bit floating-point values.

| Note Depending on how the point is rasterized, `PointCoord` may never reach (0,0) or (1,1).

`PointSize`

  Decorating a variable with the `PointSize` built-in decoration will make that variable contain the size of point primitives. The value written to the variable decorated with `PointSize` by the last vertex processing stage in the pipeline is used as the framebuffer-space size of points produced by rasterization.

  The `PointSize` decoration must be used only within mesh, vertex, tessellation control, tessellation evaluation, and geometry shaders.

  In a mesh or vertex shader, any variable decorated with `PointSize` must be declared using the `Output` storage class.

  In a tessellation control, tessellation evaluation, or geometry shader, any variable decorated with `PointSize` must be declared using either the `Input` or `Output` storage class.

  Any variable decorated with `PointSize` must be declared as a scalar 32-bit floating-point value.

| Note When `PointSize` decorates a variable in the `Input` storage class, it contains the data written to the output variable decorated with `PointSize` from the previous shader stage.

`Position`

  Decorating a variable with the `Position` built-in decoration will make that variable contain the position of the current vertex. In the last vertex processing stage, the value of the variable decorated with `Position` is used in subsequent primitive assembly, clipping, and rasterization operations.

  The `Position` decoration must be used only within mesh, vertex, tessellation control, tessellation evaluation, and geometry shaders.

  In a mesh or vertex shader, any variable decorated with `Position` must be declared using the `Output` storage class.

  In a tessellation control, tessellation evaluation, or geometry shader, any variable decorated with `Position` must not be declared in a storage class other than `Input` or `Output`.

  Any variable decorated with `Position` must be declared as a four-component vector of 32-bit floating-point values.

| Note When `Position` decorates a variable in the `Input` storage class, it contains the data written to the output variable decorated with `Position` from the previous shader stage.

`PositionPerViewNV`

  Decorating a variable with the `PositionPerViewNV` built-in decoration will make that variable contain the position of the current vertex, for each view.

  The `PositionPerViewNV` decoration must be used only within mesh, vertex, tessellation control, tessellation evaluation, and geometry shaders.

  In a vertex shader, any variable decorated with `PositionPerViewNV` must be declared using the `Output` storage class.

  In a tessellation control, tessellation evaluation, or geometry shader, any variable decorated with `PositionPerViewNV` must not be declared in a storage class other than input or output.

  Any variable decorated with `PositionPerViewNV` must be declared as an array of four-component vector of 32-bit floating-point values with at least as many elements as the maximum view in the subpass’s view mask plus one. The array must be indexed by a constant or specialization constant.

  Elements of the array correspond to views in a multiview subpass, and those elements corresponding to views in the view mask of the subpass the shader is compiled against will be used as the position value for those views. For the final vertex processing stage in the pipeline, values written to an output variable decorated with `PositionPerViewNV` are used in subsequent primitive assembly, clipping, and rasterization operations, as with `Position`. `PositionPerViewNV` output in an earlier vertex processing stage is available as an input in the subsequent vertex processing stage.

  If a shader is compiled against a subpass that has the `VK_SUBPASS_DESCRIPTION_PER_VIEW_POSITION_X_ONLY_BIT_NVX` bit set, then the position values for each view must not differ in any component other than the X component. If the values do differ, one will be chosen in an implementation-dependent manner.

`PrimitiveCountNV`

  Decorating a variable with the `PrimitiveCountNV` decoration will make that variable contain the primitive count. The primitive count specifies the number of primitives in the output mesh produced by the mesh shader that will be processed by subsequent pipeline stages.

  The `PrimitiveCountNV` decoration must only be used in mesh shaders.

  Any variable decorated with `PrimitiveCountNV` must be declared using the `Output` storage class.

  Any variable decorated with `PrimitiveCountNV` must be declared as a scalar 32-bit integer.

`PrimitiveId`

  Decorating a variable with the `PrimitiveId` built-in decoration will make that variable contain the index of the current primitive.

  The index of the first primitive generated by a drawing command is zero, and the index is incremented after every individual point, line, or triangle primitive is processed.

  For triangles drawn as points or line segments (see Polygon Mode), the primitive index is incremented only once, even if multiple points or lines are eventually drawn.

  Variables decorated with `PrimitiveId` are reset to zero between each instance drawn.

  Restarting a primitive topology using primitive restart has no effect on the value of variables decorated with `PrimitiveId`.

  In tessellation control and tessellation evaluation shaders, it will contain the index of the patch within the current set of rendering primitives that correspond to the shader invocation.

  In a geometry shader, it will contain the number of primitives presented as input to the shader since the current set of rendering primitives was started.

  In a fragment shader, it will contain the primitive index written by the geometry shader if a geometry shader is present, or with the value that would have been presented as input to the geometry shader had it been present.

  In an intersection, any-hit, or closest hit shader, it will contain the index within the geometry of the triangle or bounding box being processed.

  If a geometry shader is present and the fragment shader reads from an input variable decorated with `PrimitiveId`, then the geometry shader must write to an output variable decorated with `PrimitiveId` in all execution paths.

  If a mesh shader is present and the fragment shader reads from an input variable decorated with `PrimitiveId`, then the mesh shader must write to the output variables decorated with `PrimitiveId` in all execution paths.

  The `PrimitiveId` decoration must be used only within mesh, intersection, any-hit, closest hit, fragment, tessellation control, tessellation evaluation, and geometry shaders.

  In an intersection, any-hit, closest hit, tessellation control, or tessellation evaluation shader, any variable decorated with `PrimitiveId` must be declared using the `Input` storage class.

  In a geometry shader, any variable decorated with `PrimitiveId` must be declared using either the `Input` or `Output` storage class.

  In a mesh shader, any variable decorated with `PrimitiveId` must be declared using the `Output` storage class.

  In a fragment shader, any variable decorated with `PrimitiveId` must be declared using the `Input` storage class, and either the `Geometry` or `Tessellation` capability must also be declared.

  Any variable decorated with `PrimitiveId` must be declared as a scalar 32-bit integer.

| Note When the `PrimitiveId` decoration is applied to an output variable in the mesh shader or geometry shader, the resulting value is seen through the `PrimitiveId` decorated input variable in the fragment shader.

`PrimitiveIndicesNV`

  Decorating a variable with the `PrimitiveIndicesNV` decoration will make that variable contain the output array of vertex index values. Depending on the output primitive type declared using the execution mode, the indices are split into groups of one (`OutputPoints`), two (`OutputLinesNV`), or three (`OutputTriangles`) indices and each group generates a primitive.

  All index values must be in the range [0, N-1], where N is the value specified by the `OutputVertices` execution mode.

  The `PrimitiveIndicesNV` decoration must only be used in mesh shaders.

  Any variable decorated with `PrimitiveIndicesNV` must be declared using the `Output` storage class.

  Any variable decorated with `PrimitiveIndicesNV` must be declared as an array of scalar 32-bit integers. The array must be sized according to the primitive type and `OutputPrimitivesNV` execution modes, where the size is:

  - the value specified by `OutputPrimitivesNV` if the execution mode is `OutputPoints`,

  - two times the value specified by `OutputPrimitivesNV` if the execution mode is `OutputLinesNV`, or

  - three times the value specified by `OutputPrimitivesNV` if the execution mode is `OutputTrianglesNV`.

`RayGeometryIndexKHR`

  A variable decorated with the `RayGeometryIndexKHR` decoration will contain the generated index for the acceleration structure geometry currently being shaded.

  The `RayGeometryIndexKHR` decoration must only be used within intersection, any-hit, and closest hit shaders.

  Any variable decorated with `RayGeometryIndexKHR` must be declared using the `Input` storage class.

  Any variable decorated with `RayGeometryIndexKHR` must be declared as a scalar 32-bit integer value.

`RayTmaxKHR`

  A variable decorated with the `RayTmaxKHR` decoration will contain the parametric tmax values of the ray being processed. The values are independent of the space in which the ray and origin exist.

  The tmax value changes throughout the lifetime of the ray query that produced the intersection. In the closest hit shader, the value reflects the closest distance to the intersected primitive. In the any-hit shader, it reflects the distance to the primitive currently being intersected. In the intersection shader, it reflects the distance to the closest primitive intersected so far. The value can change in the intersection shader after calling `OpReportIntersectionKHR` if the corresponding any-hit shader does not ignore the intersection. In a miss shader, the value is identical to the parameter passed into `OpTraceRayKHR`.

  The `RayTmaxKHR` decoration must only be used with the intersection, any-hit, closest hit, and miss shaders.

  Any variable decorated with `RayTmaxKHR` must be declared with the `Input` storage class.

  Any variable decorated with `RayTmaxKHR` must be declared as a scalar 32-bit floating-point value.

`RayTminKHR`

  A variable decorated with the `RayTminKHR` decoration will contain the parametric tmin values of the ray being processed. The values are independent of the space in which the ray and origin exist.

  The tmin value remains constant for the duration of the ray query.

  The `RayTminKHR` decoration must only be used with the intersection, any-hit, closest hit, and miss shaders.

  Any variable decorated with `RayTminKHR` must be declared with the `Input` storage class.

  Any variable decorated with `RayTminKHR` must be declared as a scalar 32-bit floating-point value.

`SampleId`

  Decorating a variable with the `SampleId` built-in decoration will make that variable contain the zero-based index of the sample the invocation corresponds to. `SampleId` ranges from zero to the number of samples in the framebuffer minus one. If a fragment shader entry point’s interface includes an input variable decorated with `SampleId`, Sample Shading is considered enabled with a `minSampleShading` value of 1.0.

  The `SampleId` decoration must be used only within fragment shaders.

  The variable decorated with `SampleId` must be declared using the `Input` storage class.

  The variable decorated with `SampleId` must be declared as a scalar 32-bit integer.

`SampleMask`

  Decorating a variable with the `SampleMask` built-in decoration will make any variable contain the sample coverage mask for the current fragment shader invocation.

  A variable in the `Input` storage class decorated with `SampleMask` will contain a bitmask of the set of samples covered by the primitive generating the fragment during rasterization. It has a sample bit set if and only if the sample is considered covered for this fragment shader invocation. `SampleMask`[] is an array of integers. Bits are mapped to samples in a manner where bit B of mask M (`SampleMask[M]`) corresponds to sample 32 × M + B.

  When state specifies multiple fragment shader invocations for a given fragment, the sample mask for any single fragment shader invocation specifies the subset of the covered samples for the fragment that correspond to the invocation. In this case, the bit corresponding to each covered sample will be set in exactly one fragment shader invocation.

  If the `PostDepthCoverage` execution mode is specified, the sample is considered covered if and only if the sample is covered by the primitive and the sample passes the early per-fragment tests. Otherwise the sample is considered covered if the sample is covered by the primitive, regardless of the result of the fragment tests.

  A variable in the `Output` storage class decorated with `SampleMask` is an array of integers forming a bit array in a manner similar an input variable decorated with `SampleMask`, but where each bit represents coverage as computed by the shader. Modifying the sample mask by writing zero to a bit of `SampleMask` causes the sample to be considered uncovered. If this variable is also decorated with `OverrideCoverageNV`, the fragment coverage is replaced with the sample mask bits set in the shader otherwise the fragment coverage is `ANDed` with the bits of the sample mask. If the fragment shader is being evaluated at any frequency other than per-fragment, bits of the sample mask not corresponding to the current fragment shader invocation are ignored. This array must be sized in the fragment shader either implicitly or explicitly, to be no larger than the implementation-dependent maximum sample-mask (as an array of 32-bit elements), determined by the maximum number of samples. If a fragment shader entry point’s interface includes an output variable decorated with `SampleMask`, the sample mask will be undefined for any array elements of any fragment shader invocations that fail to assign a value. If a fragment shader entry point’s interface does not include an output variable decorated with `SampleMask`, the sample mask has no effect on the processing of a fragment.

  The `SampleMask` decoration must be used only within fragment shaders.

  Any variable decorated with `SampleMask` must be declared using either the `Input` or `Output` storage class.

  Any variable decorated with `SampleMask` must be declared as an array of 32-bit integers.

`SamplePosition`

  Decorating a variable with the `SamplePosition` built-in decoration will make that variable contain the sub-pixel position of the sample being shaded. The top left of the pixel is considered to be at coordinate (0,0) and the bottom right of the pixel is considered to be at coordinate (1,1).

  If the render pass has a fragment density map attachment, the variable will instead contain the sub-fragment position of the sample being shaded. The top left of the fragment is considered to be at coordinate (0,0) and the bottom right of the fragment is considered to be at coordinate (1,1) for any fragment area.

  If a fragment shader entry point’s interface includes an input variable decorated with `SamplePosition`, Sample Shading is considered enabled with a `minSampleShading` value of 1.0.

  The `SamplePosition` decoration must be used only within fragment shaders.

  The variable decorated with `SamplePosition` must be declared using the `Input` storage class. If the current pipeline uses custom sample locations the value of any variable decorated with the `SamplePosition` built-in decoration is undefined.

  The variable decorated with `SamplePosition` must be declared as a two-component vector of 32-bit floating-point values.

`SMCountNV`

  Decorating a variable with the `SMCountNV` built-in decoration will make that variable contain the number of SMs on the device.

  The variable decorated with `SMCountNV` must be declared using the `Input` storage class.

  The variable decorated with `SMCountNV` must be declared as a scalar 32-bit integer value.

`SMIDNV`

  Decorating a variable with the `SMIDNV` built-in decoration will make that variable contain the ID of the SM on which the current shader invocation is running. This variable is in the range [0, `SMCountNV`-1].

  The variable decorated with `SMIDNV` must be declared using the `Input` storage class.

  The variable decorated with `SMIDNV` must be declared as a scalar 32-bit integer value.

`SubgroupId`

  Decorating a variable with the `SubgroupId` built-in decoration will make that variable contain the index of the subgroup within the local workgroup. This variable is in range [0, `NumSubgroups`-1].

  The `SubgroupId` decoration must be used only within task, mesh or, compute shaders.

  The variable decorated with `SubgroupId` must be declared using the `Input` storage class.

  The variable decorated with `SubgroupId` must be declared as a scalar 32-bit integer.

`SubgroupEqMask`

  Decorating a variable with the `SubgroupEqMask` builtin decoration will make that variable contain the subgroup mask of the current subgroup invocation. The bit corresponding to the `SubgroupLocalInvocationId` is set in the variable decorated with `SubgroupEqMask`. All other bits are set to zero.

  The variable decorated with `SubgroupEqMask` must be declared using the `Input` storage class.

  The variable decorated with `SubgroupEqMask` must be declared as a four-component vector of 32-bit integer values.

  `SubgroupEqMaskKHR` is an alias of `SubgroupEqMask`.

`SubgroupGeMask`

  Decorating a variable with the `SubgroupGeMask` builtin decoration will make that variable contain the subgroup mask of the current subgroup invocation. The bits corresponding to the invocations greater than or equal to `SubgroupLocalInvocationId` through `SubgroupSize`-1 are set in the variable decorated with `SubgroupGeMask`. All other bits are set to zero.

  The variable decorated with `SubgroupGeMask` must be declared using the `Input` storage class.

  The variable decorated with `SubgroupGeMask` must be declared as a four-component vector of 32-bit integer values.

  `SubgroupGeMaskKHR` is an alias of `SubgroupGeMask`.

`SubgroupGtMask`

  Decorating a variable with the `SubgroupGtMask` builtin decoration will make that variable contain the subgroup mask of the current subgroup invocation. The bits corresponding to the invocations greater than `SubgroupLocalInvocationId` through `SubgroupSize`-1 are set in the variable decorated with `SubgroupGtMask`. All other bits are set to zero.

  The variable decorated with `SubgroupGtMask` must be declared using the `Input` storage class.

  The variable decorated with `SubgroupGtMask` must be declared as a four-component vector of 32-bit integer values.

  `SubgroupGtMaskKHR` is an alias of `SubgroupGtMask`.

`SubgroupLeMask`

  Decorating a variable with the `SubgroupLeMask` builtin decoration will make that variable contain the subgroup mask of the current subgroup invocation. The bits corresponding to the invocations less than or equal to `SubgroupLocalInvocationId` are set in the variable decorated with `SubgroupLeMask`. All other bits are set to zero.

  The variable decorated with `SubgroupLeMask` must be declared using the `Input` storage class.

  The variable decorated with `SubgroupLeMask` must be declared as a four-component vector of 32-bit integer values.

  `SubgroupLeMaskKHR` is an alias of `SubgroupLeMask`.

`SubgroupLtMask`

  Decorating a variable with the `SubgroupLtMask` builtin decoration will make that variable contain the subgroup mask of the current subgroup invocation. The bits corresponding to the invocations less than `SubgroupLocalInvocationId` are set in the variable decorated with `SubgroupLtMask`. All other bits are set to zero.

  The variable decorated with `SubgroupLtMask` must be declared using the `Input` storage class.

  The variable decorated with `SubgroupLtMask` must be declared as a four-component vector of 32-bit integer values.

  `SubgroupLtMaskKHR` is an alias of `SubgroupLtMask`.

`SubgroupLocalInvocationId`

  Decorating a variable with the `SubgroupLocalInvocationId` builtin decoration will make that variable contain the index of the invocation within the subgroup. This variable is in range [0,`SubgroupSize`-1].

  The variable decorated with `SubgroupLocalInvocationId` must be declared using the `Input` storage class.

  The variable decorated with `SubgroupLocalInvocationId` must be declared as a scalar 32-bit integer.

  | Note There is no direct relationship between `SubgroupLocalInvocationId` and `LocalInvocationId` or `LocalInvocationIndex`. If the pipeline was created with `VK_PIPELINE_SHADER_STAGE_CREATE_REQUIRE_FULL_SUBGROUPS_BIT_EXT`, applications can compute their own local invocation index to serve the same purpose: index = `SubgroupLocalInvocationId` + `SubgroupId` * `SubgroupSize` If full subgroups are not enabled, some subgroups may be dispatched with inactive invocations that don’t correspond to a local workgroup invocation, making the value of index unreliable.

`SubgroupSize`

  Decorating a variable with the `SubgroupSize` builtin decoration will make that variable contain the implementation-dependent number of invocations in a subgroup. This value must be a power-of-two integer.

  If the pipeline was created with the `VK_PIPELINE_SHADER_STAGE_CREATE_ALLOW_VARYING_SUBGROUP_SIZE_BIT_EXT` flag set, the `SubgroupSize` decorated variable will contain the subgroup size for each subgroup that gets dispatched. This value must be between minSubgroupSize and maxSubgroupSize and must be uniform with subgroup scope. The value may vary across a single draw or dispatch call, and for fragment shaders may vary across a single primitive.

  If the pipeline was created with a chained VkPipelineShaderStageRequiredSubgroupSizeCreateInfoEXT structure, the `SubgroupSize` decorated variable will match `requiredSubgroupSize`.

  If the pipeline was not created with the `VK_PIPELINE_SHADER_STAGE_CREATE_ALLOW_VARYING_SUBGROUP_SIZE_BIT_EXT` flag set and no VkPipelineShaderStageRequiredSubgroupSizeCreateInfoEXT structure was chained, the variable decorated with `SubgroupSize` will match `subgroupSize`.

  The maximum number of invocations that an implementation can support per subgroup is 128.

  The variable decorated with `SubgroupSize` must be declared using the `Input` storage class.

  The variable decorated with `SubgroupSize` must be declared as a scalar 32-bit integer.

`TaskCountNV`

  Decorating a variable with the `TaskCountNV` decoration will make that variable contain the task count. The task count specifies the number of subsequent mesh shader workgroups that get generated upon completion of the task shader.

  The `TaskCountNV` decoration must only be used in task shaders.

  Any variable decorated with `TaskCountNV` must be declared using the `Output` storage class.

  Any variable decorated with `TaskCountNV` must be declared as a scalar 32-bit integer.

`TessCoord`

  Decorating a variable with the `TessCoord` built-in decoration will make that variable contain the three-dimensional (u,v,w) barycentric coordinate of the tessellated vertex within the patch. u, v, and w are in the range [0,1] and vary linearly across the primitive being subdivided. For the tessellation modes of `Quads` or `IsoLines`, the third component is always zero.

  The `TessCoord` decoration must be used only within tessellation evaluation shaders.

  The variable decorated with `TessCoord` must be declared using the `Input` storage class.

  The variable decorated with `TessCoord` must be declared as three-component vector of 32-bit floating-point values.

`TessLevelOuter`

  Decorating a variable with the `TessLevelOuter` built-in decoration will make that variable contain the outer tessellation levels for the current patch.

  In tessellation control shaders, the variable decorated with `TessLevelOuter` can be written to, which controls the tessellation factors for the resulting patch. These values are used by the tessellator to control primitive tessellation and can be read by tessellation evaluation shaders.

  In tessellation evaluation shaders, the variable decorated with `TessLevelOuter` can read the values written by the tessellation control shader.

  The `TessLevelOuter` decoration must be used only within tessellation control and tessellation evaluation shaders.

  In a tessellation control shader, any variable decorated with `TessLevelOuter` must be declared using the `Output` storage class.

  In a tessellation evaluation shader, any variable decorated with `TessLevelOuter` must be declared using the `Input` storage class.

  Any variable decorated with `TessLevelOuter` must be declared as an array of size four, containing 32-bit floating-point values.

`TessLevelInner`

  Decorating a variable with the `TessLevelInner` built-in decoration will make that variable contain the inner tessellation levels for the current patch.

  In tessellation control shaders, the variable decorated with `TessLevelInner` can be written to, which controls the tessellation factors for the resulting patch. These values are used by the tessellator to control primitive tessellation and can be read by tessellation evaluation shaders.

  In tessellation evaluation shaders, the variable decorated with `TessLevelInner` can read the values written by the tessellation control shader.

  The `TessLevelInner` decoration must be used only within tessellation control and tessellation evaluation shaders.

  In a tessellation control shader, any variable decorated with `TessLevelInner` must be declared using the `Output` storage class.

  In a tessellation evaluation shader, any variable decorated with `TessLevelInner` must be declared using the `Input` storage class.

  Any variable decorated with `TessLevelInner` must be declared as an array of size two, containing 32-bit floating-point values.

`VertexIndex`

  Decorating a variable with the `VertexIndex` built-in decoration will make that variable contain the index of the vertex that is being processed by the current vertex shader invocation. For non-indexed draws, this variable begins at the `firstVertex` parameter to vkCmdDraw or the `firstVertex` member of a structure consumed by vkCmdDrawIndirect and increments by one for each vertex in the draw. For indexed draws, its value is the content of the index buffer for the vertex plus the `vertexOffset` parameter to vkCmdDrawIndexed or the `vertexOffset` member of the structure consumed by vkCmdDrawIndexedIndirect.

  The `VertexIndex` decoration must be used only within vertex shaders.

  The variable decorated with `VertexIndex` must be declared using the `Input` storage class.

  The variable decorated with `VertexIndex` must be declared as a scalar 32-bit integer.

| Note `VertexIndex` starts at the same starting value for each instance.

`ViewIndex`

  The `ViewIndex` decoration can be applied to a shader input which will be filled with the index of the view that is being processed by the current shader invocation.

  If multiview is enabled in the render pass, this value will be one of the bits set in the view mask of the subpass the pipeline is compiled against. If multiview is not enabled in the render pass, this value will be zero.

  The `ViewIndex` decoration must not be used within compute shaders.

  The variable decorated with `ViewIndex` must be declared using the `Input` storage class.

  The variable decorated with `ViewIndex` must be declared as a scalar 32-bit integer.

`ViewportIndex`

  Decorating a variable with the `ViewportIndex` built-in decoration will make that variable contain the index of the viewport.

  In a mesh, vertex, tessellation evaluation, or geometry shader, the variable decorated with `ViewportIndex` can be written to with the viewport index to which the primitive produced by that shader will be directed.

  The selected viewport index is used to select the viewport transform, scissor rectangle, and exclusive scissor rectangle.

  The last active vertex processing stage (in pipeline order) controls the `ViewportIndex` that is used. Outputs in previous shader stages are not used, even if the last stage fails to write the `ViewportIndex`.

  If the last active vertex processing stage shader entry point’s interface does not include a variable decorated with `ViewportIndex`, then the first viewport is used. If a vertex processing stage shader entry point’s interface includes a variable decorated with `ViewportIndex`, it must write the same value to `ViewportIndex` for all output vertices of a given primitive.

  The `ViewportIndex` decoration must be used only within mesh, vertex, tessellation evaluation, geometry, and fragment shaders. If the shaderOutputViewportIndex feature is not enabled then the `ViewportIndex` decoration must be used only with geometry, and fragment shaders.

  In a mesh, vertex, tessellation evaluation, or geometry shader, any variable decorated with `ViewportIndex` must be declared using the `Output` storage class.

  In a fragment shader, the variable decorated with `ViewportIndex` contains the viewport index of the primitive that the fragment invocation belongs to.

  In a fragment shader, any variable decorated with `ViewportIndex` must be declared using the `Input` storage class.

  Any variable decorated with `ViewportIndex` must be declared as a scalar 32-bit integer.

`ViewportMaskNV`

  Decorating a variable with the `ViewportMaskNV` built-in decoration will make that variable contain the viewport mask.

  In a mesh, vertex, tessellation evaluation, or geometry shader, the variable decorated with `ViewportMaskNV` can be written to with the mask of which viewports the primitive produced by that shader will directed.

  The `ViewportMaskNV` variable must be an array that has ⌈(`VkPhysicalDeviceLimits`::`maxViewports` / 32)⌉ elements. When a shader writes to this variable, bit B of element M controls whether a primitive is emitted to viewport 32 × M + B. The viewports indicated by the mask are used to select the viewport transform, scissor rectangle, and exclusive scissor rectangle that a primitive will be transformed by.

  The last active vertex processing stage (in pipeline order) controls the `ViewportMaskNV` that is used. Outputs in previous shader stages are not used, even if the last stage fails to write the `ViewportMaskNV`. When `ViewportMaskNV` is written by the final vertex processing stage, any variable decorated with `ViewportIndex` in the fragment shader will have the index of the viewport that was used in generating that fragment.

  If a vertex processing stage shader entry point’s interface includes a variable decorated with `ViewportMaskNV`, it must write the same value to `ViewportMaskNV` for all output vertices of a given primitive.

  The `ViewportMaskNV` decoration must be used only within mesh, vertex, tessellation evaluation, and geometry shaders.

  Any variable decorated with `ViewportMaskNV` must be declared using the `Output` storage class.

  Any variable decorated with `ViewportMaskNV` must be declared as an array of 32-bit integers.

`ViewportMaskPerViewNV`

  Decorating a variable with the `ViewportMaskPerViewNV` built-in decoration will make that variable contain the mask of viewports primitives are broadcast to, for each view.

  The `ViewportMaskPerViewNV` decoration must be used only within mesh, vertex, tessellation control, tessellation evaluation, and geometry shaders.

  Any variable decorated with `ViewportMaskPerViewNV` must be declared using the `Output` storage class.

  The value written to an element of `ViewportMaskPerViewNV` in the last vertex processing stage is a bitmask indicating which viewports the primitive will be directed to. The primitive will be broadcast to the viewport corresponding to each non-zero bit of the bitmask, and that viewport index is used to select the viewport transform, scissor rectangle, and exclusive scissor rectangle, for each view. The same values must be written to all vertices in a given primitive, or else the set of viewports used for that primitive is undefined.

  Any variable decorated with `ViewportMaskPerViewNV` must be declared as an array of scalar 32-bit integers with at least as many elements as the maximum view in the subpass’s view mask plus one. The array must be indexed by a constant or specialization constant.

  Elements of the array correspond to views in a multiview subpass, and those elements corresponding to views in the view mask of the subpass the shader is compiled against will be used as the viewport mask value for those views. `ViewportMaskPerViewNV` output in an earlier vertex processing stage is not available as an input in the subsequent vertex processing stage.

  Although `ViewportMaskNV` is an array, `ViewportMaskPerViewNV` is not a two-dimensional array. Instead, `ViewportMaskPerViewNV` is limited to 32 viewports.

`WarpsPerSMNV`

  Decorating a variable with the `WarpsPerSMNV` built-in decoration will make that variable contain the maximum number of warps executing on a SM.

  The variable decorated with `WarpsPerSMNV` must be declared using the `Input` storage class.

  The variable decorated with `WarpsPerSMNV` must be declared as a scalar 32-bit integer value.

`WarpIDNV`

  Decorating a variable with the `WarpIDNV` built-in decoration will make that variable contain the ID of the warp on a SM on which the current shader invocation is running. This variable is in the range [0, `WarpsPerSMNV`-1].

  The variable decorated with `WarpIDNV` must be declared using the `Input` storage class.

  The variable decorated with `WarpIDNV` must be declared as a scalar 32-bit integer value.

`WorkgroupId`

  Decorating a variable with the `WorkgroupId` built-in decoration will make that variable contain the global workgroup that the current invocation is a member of. Each component ranges from a base value to a base + count value, based on the parameters passed into the dispatch commands.

  The `WorkgroupId` decoration must be used only within task, mesh, or compute shaders.

  The variable decorated with `WorkgroupId` must be declared using the `Input` storage class.

  The variable decorated with `WorkgroupId` must be declared as a three-component vector of 32-bit integers.

`WorkgroupSize`

  Decorating an object with the `WorkgroupSize` built-in decoration will make that object contain the dimensions of a local workgroup. If an object is decorated with the `WorkgroupSize` decoration, this must take precedence over any execution mode set for `LocalSize`.

  The `WorkgroupSize` decoration must be used only within task, mesh, or compute shaders.

  The object decorated with `WorkgroupSize` must be a specialization constant or a constant.

  The object decorated with `WorkgroupSize` must be declared as a three-component vector of 32-bit integers.

`WorldRayDirectionKHR`

  A variable decorated with the `WorldRayDirectionKHR` decoration will specify the direction of the ray being processed, in world space.

  The `WorldRayDirectionKHR` decoration must only be used within intersection, any-hit, closest hit, and miss shaders.

  Any variable decorated with `WorldRayDirectionKHR` must be declared using the `Input` storage class.

  Any variable decorated with `WorldRayDirectionKHR` must be declared as a three-component vector of 32-bit floating-point values.

`WorldRayOriginKHR`

  A variable decorated with the `WorldRayOriginKHR` decoration will specify the origin of the ray being processed, in world space.

  The `WorldRayOriginKHR` decoration must only be used within intersection, any-hit, closest hit, and miss shaders.

  Any variable decorated with `WorldRayOriginKHR` must be declared using the `Input` storage class.

  Any variable decorated with `WorldRayOriginKHR` must be declared as a three-component vector of 32-bit floating-point values.

`WorldToObjectKHR`

  A variable decorated with the `WorldToObjectKHR` decoration will contain the current world-to-object transformation matrix, which is determined by the instance of the current intersection.

  The `WorldToObjectKHR` decoration must only be used within intersection, any-hit, and closest hit shaders.

  Any variable decorated with `WorldToObjectKHR` must be declared using the `Input` storage class.

  Any variable decorated with `WorldToObjectKHR` must be declared as a matrix with four columns of three-component vectors of 32-bit floating-point values.

## 15. Image Operations

### 15.1. Image Operations Overview

Vulkan Image Operations are operations performed by those SPIR-V Image Instructions which take an `OpTypeImage` (representing a `VkImageView`) or `OpTypeSampledImage` (representing a (`VkImageView`, `VkSampler`) pair) and texel coordinates as operands, and return a value based on one or more neighboring texture elements (texels) in the image.

| Note Texel is a term which is a combination of the words texture and element. Early interactive computer graphics supported texture operations on textures, a small subset of the image operations on images described here. The discrete samples remain essentially equivalent, however, so we retain the historical term texel to refer to them.

Image Operations include the functionality of the following SPIR-V Image Instructions:

- `OpImageSample`* and `OpImageSparseSample`* read one or more neighboring texels of the image, and filter the texel values based on the state of the sampler.

  - Instructions with `ImplicitLod` in the name determine the LOD used in the sampling operation based on the coordinates used in neighboring fragments.

  - Instructions with `ExplicitLod` in the name determine the LOD used in the sampling operation based on additional coordinates.

  - Instructions with `Proj` in the name apply homogeneous projection to the coordinates.

- `OpImageFetch` and `OpImageSparseFetch` return a single texel of the image. No sampler is used.

- `OpImage`*`Gather` and `OpImageSparse`*`Gather` read neighboring texels and return a single component of each.

- `OpImageRead` (and `OpImageSparseRead`) and `OpImageWrite` read and write, respectively, a texel in the image. No sampler is used.

- `OpImageSampleFootprintNV` identifies and returns information about the set of texels in the image that would be accessed by an equivalent `OpImageSample`* instruction.

- Instructions with `Dref` in the name apply depth comparison on the texel values.

- Instructions with `Sparse` in the name additionally return a sparse residency code.

#### 15.1.1. Texel Coordinate Systems

Images are addressed by texel coordinates. There are three texel coordinate systems:

- normalized texel coordinates [0.0, 1.0]

- unnormalized texel coordinates [0.0, width / height / depth)

- integer texel coordinates [0, width / height / depth)

SPIR-V `OpImageFetch`, `OpImageSparseFetch`, `OpImageRead`, `OpImageSparseRead`, and `OpImageWrite` instructions use integer texel coordinates. Other image instructions can use either normalized or unnormalized texel coordinates (selected by the `unnormalizedCoordinates` state of the sampler used in the instruction), but there are limitations on what operations, image state, and sampler state is supported. Normalized coordinates are logically converted to unnormalized as part of image operations, and certain steps are only performed on normalized coordinates. The array layer coordinate is always treated as unnormalized even when other coordinates are normalized.

Normalized texel coordinates are referred to as (s,t,r,q,a), with the coordinates having the following meanings:

- s: Coordinate in the first dimension of an image.

- t: Coordinate in the second dimension of an image.

- r: Coordinate in the third dimension of an image.

  - (s,t,r) are interpreted as a direction vector for Cube images.

- q: Fourth coordinate, for homogeneous (projective) coordinates.

- a: Coordinate for array layer.

The coordinates are extracted from the SPIR-V operand based on the dimensionality of the image variable and type of instruction. For `Proj` instructions, the components are in order (s [,t] [,r] q), with t and r being conditionally present based on the `Dim` of the image. For non-`Proj` instructions, the coordinates are (s [,t] [,r] [,a]), with t and r being conditionally present based on the `Dim` of the image and a being conditionally present based on the `Arrayed` property of the image. Projective image instructions are not supported on `Arrayed` images.

Unnormalized texel coordinates are referred to as (u,v,w,a), with the coordinates having the following meanings:

- u: Coordinate in the first dimension of an image.

- v: Coordinate in the second dimension of an image.

- w: Coordinate in the third dimension of an image.

- a: Coordinate for array layer.

Only the u and v coordinates are directly extracted from the SPIR-V operand, because only 1D and 2D (non-`Arrayed`) dimensionalities support unnormalized coordinates. The components are in order (u [,v]), with v being conditionally present when the dimensionality is 2D. When normalized coordinates are converted to unnormalized coordinates, all four coordinates are used.

Integer texel coordinates are referred to as (i,j,k,l,n), with the coordinates having the following meanings:

- i: Coordinate in the first dimension of an image.

- j: Coordinate in the second dimension of an image.

- k: Coordinate in the third dimension of an image.

- l: Coordinate for array layer.

- n: Coordinate for the sample index.

They are extracted from the SPIR-V operand in order (i, [,j], [,k], [,l]), with j and k conditionally present based on the `Dim` of the image, and l conditionally present based on the `Arrayed` property of the image. n is conditionally present and is taken from the `Sample` image operand.

For all coordinate types, unused coordinates are assigned a value of zero.

Figure 3. Texel Coordinate Systems, Linear Filtering

The Texel Coordinate Systems - For the example shown of an 8×4 texel two dimensional image.

- Normalized texel coordinates:

  - The s coordinate goes from 0.0 to 1.0.

  - The t coordinate goes from 0.0 to 1.0.

- Unnormalized texel coordinates:

  - The u coordinate within the range 0.0 to 8.0 is within the image, otherwise it is outside the image.

  - The v coordinate within the range 0.0 to 4.0 is within the image, otherwise it is outside the image.

- Integer texel coordinates:

  - The i coordinate within the range 0 to 7 addresses texels within the image, otherwise it is outside the image.

  - The j coordinate within the range 0 to 3 addresses texels within the image, otherwise it outside the image.

- Also shown for linear filtering:

  - Given the unnormalized coordinates (u,v), the four texels selected are i0j0, i1j0, i0j1, and i1j1.

  - The fractions α and β.

  - Given the offset Δi and Δj, the four texels selected by the offset are i0j'0, i1j'0, i0j'1, and i1j'1.

| Note For formats with reduced-resolution channels, Δi and Δj are relative to the resolution of the highest-resolution channel, and therefore may be divided by two relative to the unnormalized coordinate space of the lower-resolution channels.

Figure 4. Texel Coordinate Systems, Nearest Filtering

The Texel Coordinate Systems - For the example shown of an 8×4 texel two dimensional image.

- Texel coordinates as above. Also shown for nearest filtering:

  - Given the unnormalized coordinates (u,v), the texel selected is ij.

  - Given the offset Δi and Δj, the texel selected by the offset is ij'.

For corner-sampled images, the texel samples are located at the grid intersections instead of the texel centers.

Figure 5. Texel Coordinate Systems, Corner Sampling

### 15.2. Conversion Formulas

| editing-note (Bill) These Conversion Formulas will likely move to Section 2.7 Fixed-Point Data Conversions (RGB to sRGB and sRGB to RGB) and section 2.6 Numeric Representation and Computation (RGB to Shared Exponent and Shared Exponent to RGB)

#### 15.2.1. RGB to Shared Exponent Conversion

An RGB color (red, green, blue) is transformed to a shared exponent color (redshared, greenshared, blueshared, expshared) as follows:

First, the components (red, green, blue) are clamped to (redclamped, greenclamped, blueclamped) as:

  redclamped = max(0, min(sharedexpmax, red))

  greenclamped = max(0, min(sharedexpmax, green))

  blueclamped = max(0, min(sharedexpmax, blue))

where:

\[\begin{aligned} N & = 9 & \text{number of mantissa bits per component} \\ B & = 15 & \text{exponent bias} \\ E_{max} & = 31 & \text{maximum possible biased exponent value} \\ sharedexp_{max} & = \frac{(2^N-1)}{2^N} \times 2^{(E_{max}-B)} \end{aligned}\]

| Note NaN, if supported, is handled as in IEEE 754-2008 `minNum()` and `maxNum()`. This results in any NaN being mapped to zero.

The largest clamped component, maxclamped is determined:

  maxclamped = max(redclamped, greenclamped, blueclamped)

A preliminary shared exponent exp' is computed:

\[\begin{aligned} exp' = \begin{cases} \left \lfloor \log_2(max_{clamped}) \right \rfloor + (B+1) & \text{for}\ max_{clamped} > 2^{-(B+1)} \\ 0 & \text{for}\ max_{clamped} \leq 2^{-(B+1)} \end{cases} \end{aligned}\]

The shared exponent expshared is computed:

\[\begin{aligned} max_{shared} = \left \lfloor { \frac{max_{clamped}}{2^{(exp'-B-N)}} + \frac{1}{2} } \right \rfloor \end{aligned}\]
\[\begin{aligned} exp_{shared} = \begin{cases} exp' & \text{for}\ 0 \leq max_{shared} < 2^N \\ exp'+1 & \text{for}\ max_{shared} = 2^N \end{cases} \end{aligned}\]

Finally, three integer values in the range 0 to 2N are computed:

\[\begin{aligned} red_{shared} & = \left \lfloor { \frac{red_{clamped}}{2^{(exp_{shared}-B-N)}}+ \frac{1}{2} } \right \rfloor \\ green_{shared} & = \left \lfloor { \frac{green_{clamped}}{2^{(exp_{shared}-B-N)}}+ \frac{1}{2} } \right \rfloor \\ blue_{shared} & = \left \lfloor { \frac{blue_{clamped}}{2^{(exp_{shared}-B-N)}}+ \frac{1}{2} } \right \rfloor \end{aligned}\]

#### 15.2.2. Shared Exponent to RGB

A shared exponent color (redshared, greenshared, blueshared, expshared) is transformed to an RGB color (red, green, blue) as follows:

  \(red = red_{shared} \times {2^{(exp_{shared}-B-N)}}\)

  \(green = green_{shared} \times {2^{(exp_{shared}-B-N)}}\)

  \(blue = blue_{shared} \times {2^{(exp_{shared}-B-N)}}\)

where:

  N = 9 (number of mantissa bits per component)

  B = 15 (exponent bias)

### 15.3. Texel Input Operations

Texel input instructions are SPIR-V image instructions that read from an image. Texel input operations are a set of steps that are performed on state, coordinates, and texel values while processing a texel input instruction, and which are common to some or all texel input instructions. They include the following steps, which are performed in the listed order:

- Validation operations

  - Instruction/Sampler/Image validation

  - Coordinate validation

  - Sparse validation

  - Layout validation

- Format conversion

- Texel replacement

- Depth comparison

- Conversion to RGBA

- Component swizzle

- Chroma reconstruction

- Y′CBCR conversion

For texel input instructions involving multiple texels (for sampling or gathering), these steps are applied for each texel that is used in the instruction. Depending on the type of image instruction, other steps are conditionally performed between these steps or involving multiple coordinate or texel values.

If Chroma Reconstruction is implicit, Texel Filtering instead takes place during chroma reconstruction, before sampler Y′CBCR conversion occurs.

#### 15.3.1. Texel Input Validation Operations

Texel input validation operations inspect instruction/image/sampler state or coordinates, and in certain circumstances cause the texel value to be replaced or become undefined. There are a series of validations that the texel undergoes.

##### Instruction/Sampler/Image View Validation

There are a number of cases where a SPIR-V instruction can mismatch with the sampler, the image view, or both. There are a number of cases where the sampler can mismatch with the image view. In such cases the value of the texel returned is undefined.

These cases include:

- The sampler `borderColor` is an integer type and the image view `format` is not one of the VkFormat integer types or a stencil component of a depth/stencil format.

- The sampler `borderColor` is a float type and the image view `format` is not one of the VkFormat float types or a depth component of a depth/stencil format.

- The sampler `borderColor` is one of the opaque black colors (`VK_BORDER_COLOR_FLOAT_OPAQUE_BLACK` or `VK_BORDER_COLOR_INT_OPAQUE_BLACK`) and the image view VkComponentSwizzle for any of the VkComponentMapping components is not `VK_COMPONENT_SWIZZLE_IDENTITY`.

- The VkImageLayout of any subresource in the image view does not match that specified in VkDescriptorImageInfo::`imageLayout` used to write the image descriptor.

- If the instruction is `OpImageRead` or `OpImageSparseRead` and the `shaderStorageImageReadWithoutFormat` feature is not enabled, or the instruction is `OpImageWrite` and the `shaderStorageImageWriteWithoutFormat` feature is not enabled, then the SPIR-V Image Format must be compatible with the image view’s `format`.

- The sampler `unnormalizedCoordinates` is `VK_TRUE` and any of the limitations of unnormalized coordinates are violated.

- The sampler was created with `flags` containing `VK_SAMPLER_CREATE_SUBSAMPLED_BIT_EXT` and the image was not created with `flags` containing `VK_IMAGE_CREATE_SUBSAMPLED_BIT_EXT`.

- The sampler was not created with `flags` containing `VK_SAMPLER_CREATE_SUBSAMPLED_BIT_EXT` and the image was created with `flags` containing `VK_IMAGE_CREATE_SUBSAMPLED_BIT_EXT`.

- The sampler was created with `flags` containing `VK_SAMPLER_CREATE_SUBSAMPLED_BIT_EXT` and is used with a function that is not `OpImageSampleImplicitLod` or `OpImageSampleExplicitLod`, or is used with operands `Offset` or `ConstOffsets`.

- The SPIR-V instruction is one of the `OpImage`*`Dref`* instructions and the sampler `compareEnable` is `VK_FALSE`

- The SPIR-V instruction is not one of the `OpImage`*`Dref`* instructions and the sampler `compareEnable` is `VK_TRUE`

- The SPIR-V instruction is one of the `OpImage`*`Dref`* instructions and the image view `format` is not one of the depth/stencil formats with a depth component, or the image view aspect is not `VK_IMAGE_ASPECT_DEPTH_BIT`.

- The SPIR-V instruction’s image variable’s properties are not compatible with the image view:

  - Rules for `viewType`:

    - `VK_IMAGE_VIEW_TYPE_1D` must have `Dim` = 1D, `Arrayed` = 0, `MS` = 0.

    - `VK_IMAGE_VIEW_TYPE_2D` must have `Dim` = 2D, `Arrayed` = 0.

    - `VK_IMAGE_VIEW_TYPE_3D` must have `Dim` = 3D, `Arrayed` = 0, `MS` = 0.

    - `VK_IMAGE_VIEW_TYPE_CUBE` must have `Dim` = Cube, `Arrayed` = 0, `MS` = 0.

    - `VK_IMAGE_VIEW_TYPE_1D_ARRAY` must have `Dim` = 1D, `Arrayed` = 1, `MS` = 0.

    - `VK_IMAGE_VIEW_TYPE_2D_ARRAY` must have `Dim` = 2D, `Arrayed` = 1.

    - `VK_IMAGE_VIEW_TYPE_CUBE_ARRAY` must have `Dim` = Cube, `Arrayed` = 1, `MS` = 0.

  - If the image was created with VkImageCreateInfo::`samples` equal to `VK_SAMPLE_COUNT_1_BIT`, the instruction must have `MS` = 0.

  - If the image was created with VkImageCreateInfo::`samples` not equal to `VK_SAMPLE_COUNT_1_BIT`, the instruction must have `MS` = 1.

- If the image was created with VkImageCreateInfo::`flags` containing `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV`, the sampler addressing modes must only use a VkSamplerAddressMode of `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`.

- The SPIR-V instruction is `OpImageSampleFootprintNV` with `Dim` = 2D and `addressModeU` or `addressModeV` in the sampler is not `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`.

- The SPIR-V instruction is `OpImageSampleFootprintNV` with `Dim` = 3D and `addressModeU`, `addressModeV`, or `addressModeW` in the sampler is not `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`.

Only `OpImageSample`* and `OpImageSparseSample`* can be used with a sampler that enables sampler Y′CBCR conversion.

`OpImageFetch`, `OpImageSparseFetch`, `OpImage`*`Gather`, and `OpImageSparse`*`Gather` must not be used with a sampler that enables sampler Y′CBCR conversion.

The `ConstOffset` and `Offset` operands must not be used with a sampler that enables sampler Y′CBCR conversion.

##### Integer Texel Coordinate Validation

Integer texel coordinates are validated against the size of the image level, and the number of layers and number of samples in the image. For SPIR-V instructions that use integer texel coordinates, this is performed directly on the integer coordinates. For instructions that use normalized or unnormalized texel coordinates, this is performed on the coordinates that result after conversion to integer texel coordinates.

If the integer texel coordinates do not satisfy all of the conditions

  0 ≤ i < ws

  0 ≤ j < hs

  0 ≤ k < ds

  0 ≤ l < layers

  0 ≤ n < samples

where:

  ws = width of the image level

  hs = height of the image level

  ds = depth of the image level

  layers = number of layers in the image

  samples = number of samples per texel in the image

then the texel fails integer texel coordinate validation.

There are four cases to consider:

1. Valid Texel Coordinates

   - If the texel coordinates pass validation (that is, the coordinates lie within the image),

   then the texel value comes from the value in image memory.

2. Border Texel

   - If the texel coordinates fail validation, and

   - If the read is the result of an image sample instruction or image gather instruction, and

   - If the image is not a cube image,

   then the texel is a border texel and texel replacement is performed.

3. Invalid Texel

   - If the texel coordinates fail validation, and

   - If the read is the result of an image fetch instruction, image read instruction, or atomic instruction,

   then the texel is an invalid texel and texel replacement is performed.

4. Cube Map Edge or Corner

   Otherwise the texel coordinates lie beyond the edges or corners of the selected cube map face, and Cube map edge handling is performed.

##### Cube Map Edge Handling

If the texel coordinates lie beyond the edges or corners of the selected cube map face, the following steps are performed. Note that this does not occur when using `VK_FILTER_NEAREST` filtering within a mip level, since `VK_FILTER_NEAREST` is treated as using `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`.

- Cube Map Edge Texel

  - If the texel lies beyond the selected cube map face in either only i or only j, then the coordinates (i,j) and the array layer l are transformed to select the adjacent texel from the appropriate neighboring face.

- Cube Map Corner Texel

  - If the texel lies beyond the selected cube map face in both i and j, then there is no unique neighboring face from which to read that texel. The texel should be replaced by the average of the three values of the adjacent texels in each incident face. However, implementations may replace the cube map corner texel by other methods. The methods are subject to the constraint that for linear filtering if the three available texels have the same value, the resulting filtered texel must have that value, and for cubic filtering if the twelve available samples have the same value, the resulting filtered texel must have that value.

##### Sparse Validation

If the texel reads from an unbound region of a sparse image, the texel is a sparse unbound texel, and processing continues with texel replacement.

##### Layout Validation

If all planes of a disjoint multi-planar image are not in the same image layout, the image must not be sampled with sampler Y′CBCR conversion enabled.

#### 15.3.2. Format Conversion

Texels undergo a format conversion from the VkFormat of the image view to a vector of either floating point or signed or unsigned integer components, with the number of components based on the number of components present in the format.

- Color formats have one, two, three, or four components, according to the format.

- Depth/stencil formats are one component. The depth or stencil component is selected by the `aspectMask` of the image view.

Each component is converted based on its type and size (as defined in the Format Definition section for each VkFormat), using the appropriate equations in 16-Bit Floating-Point Numbers, Unsigned 11-Bit Floating-Point Numbers, Unsigned 10-Bit Floating-Point Numbers, Fixed-Point Data Conversion, and Shared Exponent to RGB. Signed integer components smaller than 32 bits are sign-extended.

If the image view format is sRGB, the color components are first converted as if they are UNORM, and then sRGB to linear conversion is applied to the R, G, and B components as described in the “sRGB EOTF” section of the Khronos Data Format Specification. The A component, if present, is unchanged.

If the image view format is block-compressed, then the texel value is first decoded, then converted based on the type and number of components defined by the compressed format.

#### 15.3.3. Texel Replacement

A texel is replaced if it is one (and only one) of:

- a border texel,

- an invalid texel, or

- a sparse unbound texel.

Border texels are replaced with a value based on the image format and the `borderColor` of the sampler. The border color is:

Table 22. Border Color B
Sampler `borderColor` | Corresponding Border Color
--- | ---
`VK_BORDER_COLOR_FLOAT_TRANSPARENT_BLACK` | [Br, Bg, Bb, Ba] = [0.0, 0.0, 0.0, 0.0]
`VK_BORDER_COLOR_FLOAT_OPAQUE_BLACK` | [Br, Bg, Bb, Ba] = [0.0, 0.0, 0.0, 1.0]
`VK_BORDER_COLOR_FLOAT_OPAQUE_WHITE` | [Br, Bg, Bb, Ba] = [1.0, 1.0, 1.0, 1.0]
`VK_BORDER_COLOR_INT_TRANSPARENT_BLACK` | [Br, Bg, Bb, Ba] = [0, 0, 0, 0]
`VK_BORDER_COLOR_INT_OPAQUE_BLACK` | [Br, Bg, Bb, Ba] = [0, 0, 0, 1]
`VK_BORDER_COLOR_INT_OPAQUE_WHITE` | [Br, Bg, Bb, Ba] = [1, 1, 1, 1]

| Note The names `VK_BORDER_COLOR_*_TRANSPARENT_BLACK`, `VK_BORDER_COLOR_*_OPAQUE_BLACK`, and `VK_BORDER_COLOR_*_OPAQUE_WHITE` are meant to describe which components are zeros and ones in the vocabulary of compositing, and are not meant to imply that the numerical value of `VK_BORDER_COLOR_INT_OPAQUE_WHITE` is a saturating value for integers.

This is substituted for the texel value by replacing the number of components in the image format

Table 23. Border Texel Components After Replacement
Texel Aspect or Format | Component Assignment
--- | ---
Depth aspect | D = Br
Stencil aspect | S = Br
One component color format | Colorr = Br
Two component color format | [Colorr,Colorg] = [Br,Bg]
Three component color format | [Colorr,Colorg,Colorb] = [Br,Bg,Bb]
Four component color format | [Colorr,Colorg,Colorb,Colora] = [Br,Bg,Bb,Ba]

The value returned by a read of an invalid texel is undefined, unless that read operation is from a buffer resource and the `robustBufferAccess` feature is enabled. In that case, an invalid texel is replaced as described by the `robustBufferAccess` feature.

If the VkPhysicalDeviceSparseProperties::`residencyNonResidentStrict` property is `VK_TRUE`, a sparse unbound texel is replaced with 0 or 0.0 values for integer and floating-point components of the image format, respectively.

If `residencyNonResidentStrict` is `VK_FALSE`, the value of the sparse unbound texel is undefined.

#### 15.3.4. Depth Compare Operation

If the image view has a depth/stencil format, the depth component is selected by the `aspectMask`, and the operation is a `Dref` instruction, a depth comparison is performed. The value of the result D is 1.0 if the result of the compare operation is true, and 0.0 otherwise. The compare operation is selected by the `compareOp` member of the sampler.

\[\begin{aligned} D & = 1.0 & \begin{cases} D_{\textit{ref}} \leq D & \text{for LEQUAL} \\ D_{\textit{ref}} \geq D & \text{for GEQUAL} \\ D_{\textit{ref}} < D & \text{for LESS} \\ D_{\textit{ref}} > D & \text{for GREATER} \\ D_{\textit{ref}} = D & \text{for EQUAL} \\ D_{\textit{ref}} \neq D & \text{for NOTEQUAL} \\ \textit{true} & \text{for ALWAYS} \\ \textit{false} & \text{for NEVER} \end{cases} \\ D & = 0.0 & \text{otherwise} \end{aligned}\]

where, in the depth comparison:

  Dref = shaderOp.Dref (from optional SPIR-V operand)

  D (texel depth value)

#### 15.3.5. Conversion to RGBA

The texel is expanded from one, two, or three components to four components based on the image base color:

Table 24. Texel Color After Conversion To RGBA
Texel Aspect or Format | RGBA Color
--- | ---
Depth aspect | [Colorr,Colorg,Colorb, Colora] = [D,0,0,one]
Stencil aspect | [Colorr,Colorg,Colorb, Colora] = [S,0,0,one]
One component color format | [Colorr,Colorg,Colorb, Colora] = [Colorr,0,0,one]
Two component color format | [Colorr,Colorg,Colorb, Colora] = [Colorr,Colorg,0,one]
Three component color format | [Colorr,Colorg,Colorb, Colora] = [Colorr,Colorg,Colorb,one]
Four component color format | [Colorr,Colorg,Colorb, Colora] = [Colorr,Colorg,Colorb,Colora]

where one = 1.0f for floating-point formats and depth aspects, and one = 1 for integer formats and stencil aspects.

#### 15.3.6. Component Swizzle

All texel input instructions apply a swizzle based on:

- the VkComponentSwizzle enums in the `components` member of the VkImageViewCreateInfo structure for the image being read if sampler Y′CBCR conversion is not enabled, and

- the VkComponentSwizzle enums in the `components` member of the VkSamplerYcbcrConversionCreateInfo structure for the sampler Y′CBCR conversion if sampler Y′CBCR conversion is enabled.

The swizzle can rearrange the components of the texel, or substitute zero or one for any components. It is defined as follows for each color component:

\[\begin{aligned} Color'_{component} & = \begin{cases} Color_r & \text{for RED swizzle} \\ Color_g & \text{for GREEN swizzle} \\ Color_b & \text{for BLUE swizzle} \\ Color_a & \text{for ALPHA swizzle} \\ 0 & \text{for ZERO swizzle} \\ one & \text{for ONE swizzle} \\ identity & \text{for IDENTITY swizzle} \end{cases} \end{aligned}\]

where:

\[\begin{aligned} one & = \begin{cases} & 1.0\text{f} & \text{for floating point components} \\ & 1 & \text{for integer components} \\ \end{cases} \\ identity & = \begin{cases} & Color_r & \text{for}\ component = r \\ & Color_g & \text{for}\ component = g \\ & Color_b & \text{for}\ component = b \\ & Color_a & \text{for}\ component = a \\ \end{cases} \end{aligned}\]

If the border color is one of the `VK_BORDER_COLOR_*_OPAQUE_BLACK` enums and the VkComponentSwizzle is not `VK_COMPONENT_SWIZZLE_IDENTITY` for all components (or the equivalent identity mapping), the value of the texel after swizzle is undefined.

#### 15.3.7. Sparse Residency

`OpImageSparse`* instructions return a structure which includes a residency code indicating whether any texels accessed by the instruction are sparse unbound texels. This code can be interpreted by the `OpImageSparseTexelsResident` instruction which converts the residency code to a boolean value.

#### 15.3.8. Chroma Reconstruction

In some color models, the color representation is defined in terms of monochromatic light intensity (often called “luma”) and color differences relative to this intensity, often called “chroma”. It is common for color models other than RGB to represent the chroma channels at lower spatial resolution than the luma channel. This approach is used to take advantage of the eye’s lower spatial sensitivity to color compared with its sensitivity to brightness. Less commonly, the same approach is used with additive color, since the green channel dominates the eye’s sensitivity to light intensity and the spatial sensitivity to color introduced by red and blue is lower.

Lower-resolution channels are “downsampled” by resizing them to a lower spatial resolution than the channel representing luminance. The process of reconstructing a full color value for texture access involves accessing both chroma and luma values at the same location. To generate the color accurately, the values of the lower-resolution channels at the location of the luma samples must be reconstructed from the lower-resolution sample locations, an operation known here as “chroma reconstruction” irrespective of the actual color model.

The location of the chroma samples relative to the luma coordinates is determined by the `xChromaOffset` and `yChromaOffset` members of the VkSamplerYcbcrConversionCreateInfo structure used to create the sampler Y′CBCR conversion.

The following diagrams show the relationship between unnormalized (u,v) coordinates and (i,j) integer texel positions in the luma channel (shown in black, with circles showing integer sample positions) and the texel coordinates of reduced-resolution chroma channels, shown as crosses in red.

| Note If the chroma values are reconstructed at the locations of the luma samples by means of interpolation, chroma samples from outside the image bounds are needed; these are determined according to Wrapping Operation. These diagrams represent this by showing the bounds of the “chroma texel” extending beyond the image bounds, and including additional chroma sample positions where required for interpolation. The limits of a sample for `NEAREST` sampling is shown as a grid.

Figure 6. 422 downsampling, xChromaOffset=COSITED_EVEN
Figure 7. 422 downsampling, xChromaOffset=MIDPOINT
Figure 8. 420 downsampling, xChromaOffset=COSITED_EVEN, yChromaOffset=COSITED_EVEN
Figure 9. 420 downsampling, xChromaOffset=MIDPOINT, yChromaOffset=COSITED_EVEN
Figure 10. 420 downsampling, xChromaOffset=COSITED_EVEN, yChromaOffset=MIDPOINT
Figure 11. 420 downsampling, xChromaOffset=MIDPOINT, yChromaOffset=MIDPOINT

Reconstruction is implemented in one of two ways:

If the format of the image that is to be sampled sets `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_BIT`, or the `VkSamplerYcbcrConversionCreateInfo`’s `forceExplicitReconstruction` is set to `VK_TRUE`, reconstruction is performed as an explicit step independent of filtering, described in the Explicit Reconstruction section.

If the format of the image that is to be sampled does not set `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_BIT` and if the `VkSamplerYcbcrConversionCreateInfo`’s `forceExplicitReconstruction` is set to `VK_FALSE`, reconstruction is performed as an implicit part of filtering prior to color model conversion, with no separate post-conversion texel filtering step, as described in the Implicit Reconstruction section.

##### Explicit Reconstruction

- If the `chromaFilter` member of the VkSamplerYcbcrConversionCreateInfo structure is `VK_FILTER_NEAREST`:

  - If the format’s R and B channels are reduced in resolution in just width by a factor of two relative to the G channel (i.e. this is a “`_422`” format), the \(\tau_{ijk}[level]\) values accessed by texel filtering are reconstructed as follows:

    \[\begin{aligned} \tau_R'(i, j) & = \tau_R(\lfloor{i\times 0.5}\rfloor, j)[level] \\ \tau_B'(i, j) & = \tau_B(\lfloor{i\times 0.5}\rfloor, j)[level] \end{aligned}\]

  - If the format’s R and B channels are reduced in resolution in width and height by a factor of two relative to the G channel (i.e. this is a “`_420`” format), the \(\tau_{ijk}[level]\) values accessed by texel filtering are reconstructed as follows:

    \[\begin{aligned} \tau_R'(i, j) & = \tau_R(\lfloor{i\times 0.5}\rfloor, \lfloor{j\times 0.5}\rfloor)[level] \\ \tau_B'(i, j) & = \tau_B(\lfloor{i\times 0.5}\rfloor, \lfloor{j\times 0.5}\rfloor)[level] \end{aligned}\]

    | Note `xChromaOffset` and `yChromaOffset` have no effect if `chromaFilter` is `VK_FILTER_NEAREST` for explicit reconstruction.

- If the `chromaFilter` member of the VkSamplerYcbcrConversionCreateInfo structure is `VK_FILTER_LINEAR`:

  - If the format’s R and B channels are reduced in resolution in just width by a factor of two relative to the G channel (i.e. this is a “422” format):

    - If `xChromaOffset` is `VK_CHROMA_LOCATION_COSITED_EVEN`:

      \[\tau_{RB}'(i,j) = \begin{cases} \tau_{RB}(\lfloor{i\times 0.5}\rfloor,j)[level], & 0.5 \times i = \lfloor{0.5 \times i}\rfloor\\ 0.5\times\tau_{RB}(\lfloor{i\times 0.5}\rfloor,j)[level] + \\ 0.5\times\tau_{RB}(\lfloor{i\times 0.5}\rfloor + 1,j)[level], & 0.5 \times i \neq \lfloor{0.5 \times i}\rfloor \end{cases}\]

    - If `xChromaOffset` is `VK_CHROMA_LOCATION_MIDPOINT`:

      \[\tau_{RB}(i,j)' = \begin{cases} 0.25 \times \tau_{RB}(\lfloor{i\times 0.5}\rfloor - 1,j)[level] + \\ 0.75 \times \tau_{RB}(\lfloor{i\times 0.5}\rfloor,j)[level], & 0.5 \times i = \lfloor{0.5 \times i}\rfloor\\ 0.75 \times \tau_{RB}(\lfloor{i\times 0.5}\rfloor,j)[level] + \\ 0.25 \times \tau_{RB}(\lfloor{i\times 0.5}\rfloor + 1,j)[level], & 0.5 \times i \neq \lfloor{0.5 \times i}\rfloor \end{cases}\]

  - If the format’s R and B channels are reduced in resolution in width and height by a factor of two relative to the G channel (i.e. this is a “420” format), a similar relationship applies. Due to the number of options, these formulae are expressed more concisely as follows:

    \[\begin{aligned} i_{RB} & = \begin{cases} 0.5 \times (i) & \textrm{If xChromaOffset = COSITED}\_\textrm{EVEN} \\ 0.5 \times (i - 0.5) & \textrm{If xChromaOffset = MIDPOINT} \end{cases}\\ j_{RB} & = \begin{cases} 0.5 \times (j) & \textrm{If yChromaOffset = COSITED}\_\textrm{EVEN} \\ 0.5 \times (j - 0.5) & \textrm{If yChromaOffset = MIDPOINT} \end{cases}\\ \\ i_{floor} & = \lfloor i_{RB} \rfloor \\ j_{floor} & = \lfloor j_{RB} \rfloor \\ \\ i_{frac} & = i_{RB} - i_{floor} \\ j_{frac} & = j_{RB} - j_{floor} \end{aligned}\]
    \[\begin{aligned} \tau_{RB}'(i,j) = & \tau_{RB}( i_{floor}, j_{floor})[level] & \times & ( 1 - i_{frac} ) & & \times & ( 1 - j_{frac} ) & + \\ & \tau_{RB}( 1 + i_{floor}, j_{floor})[level] & \times & ( i_{frac} ) & & \times & ( 1 - j_{frac} ) & + \\ & \tau_{RB}( i_{floor}, 1 + j_{floor})[level] & \times & ( 1 - i_{frac} ) & & \times & ( j_{frac} ) & + \\ & \tau_{RB}( 1 + i_{floor}, 1 + j_{floor})[level] & \times & ( i_{frac} ) & & \times & ( j_{frac} ) & \end{aligned}\]

| Note In the case where the texture itself is bilinearly interpolated as described in Texel Filtering, thus requiring four full-color samples for the filtering operation, and where the reconstruction of these samples uses bilinear interpolation in the chroma channels due to `chromaFilter`=`VK_FILTER_LINEAR`, up to nine chroma samples may be required, depending on the sample location.

##### Implicit Reconstruction

Implicit reconstruction takes place by the samples being interpolated, as required by the filter settings of the sampler, except that `chromaFilter` takes precedence for the chroma samples.

If `chromaFilter` is `VK_FILTER_NEAREST`, an implementation may behave as if `xChromaOffset` and `yChromaOffset` were both `VK_CHROMA_LOCATION_MIDPOINT`, irrespective of the values set.

| Note This will not have any visible effect if the locations of the luma samples coincide with the location of the samples used for rasterization.

The sample coordinates are adjusted by the downsample factor of the channel (such that, for example, the sample coordinates are divided by two if the channel has a downsample factor of two relative to the luma channel):

\[\begin{aligned} u_{RB}' (422/420) &= \begin{cases} 0.5\times (u + 0.5), & \textrm{xChromaOffset = COSITED}\_\textrm{EVEN} \\ 0.5\times u, & \textrm{xChromaOffset = MIDPOINT} \end{cases} \\ v_{RB}' (420) &= \begin{cases} 0.5\times (v + 0.5), & \textrm{yChromaOffset = COSITED}\_\textrm{EVEN} \\ 0.5\times v, & \textrm{yChromaOffset = MIDPOINT} \end{cases} \end{aligned}\]

#### 15.3.9. Sampler Y′CBCR Conversion

Sampler Y′CBCR conversion performs the following operations, which an implementation may combine into a single mathematical operation:

- Sampler Y′CBCR Range Expansion

- Sampler Y′CBCR Model Conversion

##### Sampler Y′CBCR Range Expansion

Sampler Y′CBCR range expansion is applied to color channel values after all texel input operations which are not specific to sampler Y′CBCR conversion. For example, the input values to this stage have been converted using the normal format conversion rules.

Sampler Y′CBCR range expansion is not applied if `ycbcrModel` is `VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY`. That is, the shader receives the vector C'rgba as output by the Component Swizzle stage without further modification.

For other values of `ycbcrModel`, range expansion is applied to the texel channel values output by the Component Swizzle defined by the `components` member of VkSamplerYcbcrConversionCreateInfo. Range expansion applies independently to each channel of the image. For the purposes of range expansion and Y′CBCR model conversion, the R and B channels contain color difference (chroma) values and the G channel contains luma. The A channel is not modified by sampler Y′CBCR range expansion.

The range expansion to be applied is defined by the `ycbcrRange` member of the `VkSamplerYcbcrConversionCreateInfo` structure:

- If `ycbcrRange` is `VK_SAMPLER_YCBCR_RANGE_ITU_FULL`, the following transformations are applied:

  \[\begin{aligned} Y' &= C'_{rgba}[G] \\ C_B &= C'_{rgba}[B] - {{2^{(n-1)}}\over{(2^n) - 1}} \\ C_R &= C'_{rgba}[R] - {{2^{(n-1)}}\over{(2^n) - 1}} \end{aligned}\]

  | Note These formulae correspond to the “full range” encoding in the “Quantization schemes” chapter of the Khronos Data Format Specification. Should any future amendments be made to the ITU specifications from which these equations are derived, the formulae used by Vulkan may also be updated to maintain parity.

- If `ycbcrRange` is `VK_SAMPLER_YCBCR_RANGE_ITU_NARROW`, the following transformations are applied:

  \[\begin{aligned} Y' &= {{C'_{rgba}[G] \times (2^n-1) - 16\times 2^{n-8}}\over{219\times 2^{n-8}}} \\ C_B &= {{C'_{rgba}[B] \times \left(2^n-1\right) - 128\times 2^{n-8}}\over{224\times 2^{n-8}}} \\ C_R &= {{C'_{rgba}[R] \times \left(2^n-1\right) - 128\times 2^{n-8}}\over{224\times 2^{n-8}}} \end{aligned}\]

  | Note These formulae correspond to the “narrow range” encoding in the “Quantization schemes” chapter of the Khronos Data Format Specification.

- n is the bit-depth of the channels in the format.

The precision of the operations performed during range expansion must be at least that of the source format.

An implementation may clamp the results of these range expansion operations such that Y′ falls in the range [0,1], and/or such that CB and CR fall in the range [-0.5,0.5].

##### Sampler Y′CBCR Model Conversion

The range-expanded values are converted between color models, according to the color model conversion specified in the `ycbcrModel` member:

`VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY`

  The color channels are not modified by the color model conversion since they are assumed already to represent the desired color model in which the shader is operating; Y′CBCR range expansion is also ignored.

`VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_IDENTITY`

  The color channels are not modified by the color model conversion and are assumed to be treated as though in Y′CBCR form both in memory and in the shader; Y′CBCR range expansion is applied to the channels as for other Y′CBCR models, with the vector (CR,Y′,CB,A) provided to the shader.

`VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_709`

  The color channels are transformed from a Y′CBCR representation to an R′G′B′ representation as described in the “BT.709 Y′CBCR conversion” section of the Khronos Data Format Specification.

`VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_601`

  The color channels are transformed from a Y′CBCR representation to an R′G′B′ representation as described in the “BT.601 Y′CBCR conversion” section of the Khronos Data Format Specification.

`VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_2020`

  The color channels are transformed from a Y′CBCR representation to an R′G′B′ representation as described in the “BT.2020 Y′CBCR conversion” section of the Khronos Data Format Specification.

In this operation, each output channel is dependent on each input channel.

An implementation may clamp the R′G′B′ results of these conversions to the range [0,1].

The precision of the operations performed during model conversion must be at least that of the source format.

The alpha channel is not modified by these model conversions.

| Note Sampling operations in a non-linear color space can introduce color and intensity shifts at sharp transition boundaries. To avoid this issue, the technically precise color correction sequence described in the “Introduction to Color Conversions” chapter of the Khronos Data Format Specification may be performed as follows: Calculate the unnormalized texel coordinates corresponding to the desired sample position. For a `minFilter` or `magFilter` of `VK_FILTER_NEAREST`: Calculate (i,j) for the sample location as described under the “nearest filtering” formulae in (u,v,w,a) to (i,j,k,l,n) Transformation And Array Layer Selection Calculate the normalized texel coordinates corresponding to these integer coordinates. Sample using sampler Y′CBCR conversion at this location. For a `minFilter` or `magFilter` of `VK_FILTER_LINEAR`: Calculate (i[0,1],j[0,1]) for the sample location as described under the “linear filtering” formulae in (u,v,w,a) to (i,j,k,l,n) Transformation And Array Layer Selection Calculate the normalized texel coordinates corresponding to these integer coordinates. Sample using sampler Y′CBCR conversion at each of these locations. Convert the non-linear A′R′G′B′ outputs of the Y′CBCR conversions to linear ARGB values as described in the “Transfer Functions” chapter of the Khronos Data Format Specification. Interpolate the linear ARGB values using the α and β values described in the “linear filtering” section of (u,v,w,a) to (i,j,k,l,n) Transformation And Array Layer Selection and the equations in Texel Filtering. The additional calculations and, especially, additional number of sampling operations in the `VK_FILTER_LINEAR` case can be expected to have a performance impact compared with using the outputs directly; since the variation from “correct” results are subtle for most content, the application author should determine whether a more costly implementation is strictly necessary. Note that if `chromaFilter`, and `minFilter` or `magFilter` are both `VK_FILTER_NEAREST`, these operations are redundant and sampling using sampler Y′CBCR conversion at the desired sample coordinates will produce the “correct” results without further processing.

### 15.4. Texel Output Operations

Texel output instructions are SPIR-V image instructions that write to an image. Texel output operations are a set of steps that are performed on state, coordinates, and texel values while processing a texel output instruction, and which are common to some or all texel output instructions. They include the following steps, which are performed in the listed order:

- Validation operations

  - Format validation

  - Coordinate validation

  - Sparse validation

- Texel output format conversion

#### 15.4.1. Texel Output Validation Operations

Texel output validation operations inspect instruction/image state or coordinates, and in certain circumstances cause the write to have no effect. There are a series of validations that the texel undergoes.

##### Texel Format Validation

If the image format of the `OpTypeImage` is not compatible with the `VkImageView`’s `format`, the write causes the contents of the image’s memory to become undefined.

#### 15.4.2. Integer Texel Coordinate Validation

The integer texel coordinates are validated according to the same rules as for texel input coordinate validation.

If the texel fails integer texel coordinate validation, then the write has no effect.

#### 15.4.3. Sparse Texel Operation

If the texel attempts to write to an unbound region of a sparse image, the texel is a sparse unbound texel. In such a case, if the VkPhysicalDeviceSparseProperties::`residencyNonResidentStrict` property is `VK_TRUE`, the sparse unbound texel write has no effect. If `residencyNonResidentStrict` is `VK_FALSE`, the write may have a side effect that becomes visible to other accesses to unbound texels in any resource, but will not be visible to any device memory allocated by the application.

#### 15.4.4. Texel Output Format Conversion

If the image format is sRGB, a linear to sRGB conversion is applied to the R, G, and B components as described in the “sRGB EOTF” section of the Khronos Data Format Specification. The A component, if present, is unchanged.

Texels then undergo a format conversion from the floating point, signed, or unsigned integer type of the texel data to the VkFormat of the image view. Any unused components are ignored.

Each component is converted based on its type and size (as defined in the Format Definition section for each VkFormat). Floating-point outputs are converted as described in Floating-Point Format Conversions and Fixed-Point Data Conversion. Integer outputs are converted such that their value is preserved. The converted value of any integer that cannot be represented in the target format is undefined.

### 15.5. Normalized Texel Coordinate Operations

If the image sampler instruction provides normalized texel coordinates, some of the following operations are performed.

#### 15.5.1. Projection Operation

For `Proj` image operations, the normalized texel coordinates (s,t,r,q,a) and (if present) the Dref coordinate are transformed as follows:

\[\begin{aligned} s & = \frac{s}{q}, & \text{for 1D, 2D, or 3D image} \\ \\ t & = \frac{t}{q}, & \text{for 2D or 3D image} \\ \\ r & = \frac{r}{q}, & \text{for 3D image} \\ \\ D_{\textit{ref}} & = \frac{D_{\textit{ref}}}{q}, & \text{if provided} \end{aligned}\]

#### 15.5.2. Derivative Image Operations

Derivatives are used for LOD selection. These derivatives are either implicit (in an `ImplicitLod` image instruction in a fragment shader) or explicit (provided explicitly by shader to the image instruction in any shader).

For implicit derivatives image instructions, the derivatives of texel coordinates are calculated in the same manner as derivative operations. That is:

\[\begin{aligned} \partial{s}/\partial{x} & = dPdx(s), & \partial{s}/\partial{y} & = dPdy(s), & \text{for 1D, 2D, Cube, or 3D image} \\ \partial{t}/\partial{x} & = dPdx(t), & \partial{t}/\partial{y} & = dPdy(t), & \text{for 2D, Cube, or 3D image} \\ \partial{u}/\partial{x} & = dPdx(u), & \partial{u}/\partial{y} & = dPdy(u), & \text{for Cube or 3D image} \end{aligned}\]

Partial derivatives not defined above for certain image dimensionalities are set to zero.

For explicit LOD image instructions, if the optional SPIR-V operand Grad is provided, then the operand values are used for the derivatives. The number of components present in each derivative for a given image dimensionality matches the number of partial derivatives computed above.

If the optional SPIR-V operand Lod is provided, then derivatives are set to zero, the cube map derivative transformation is skipped, and the scale factor operation is skipped. Instead, the floating point scalar coordinate is directly assigned to λbase as described in Level-of-Detail Operation.

If the image or sampler object used by an implicit derivative image instruction is not uniform across the quad and `quadDivergentImplicitLod` is not supported, then the derivative and LOD values are undefined. Implicit derivatives are well-defined when the image and sampler and control flow are uniform across the quad, even if they diverge between different quads.

If `quadDivergentImplicitLod` is supported, then derivatives and implicit LOD values are well-defined even if the image or sampler object are not uniform within a quad. The derivatives are computed as specified above, and the implicit LOD calculation proceeds for each shader invocation using its respective image and sampler object.

#### 15.5.3. Cube Map Face Selection and Transformations

For cube map image instructions, the (s,t,r) coordinates are treated as a direction vector (rx,ry,rz). The direction vector is used to select a cube map face. The direction vector is transformed to a per-face texel coordinate system (sface,tface), The direction vector is also used to transform the derivatives to per-face derivatives.

#### 15.5.4. Cube Map Face Selection

The direction vector selects one of the cube map’s faces based on the largest magnitude coordinate direction (the major axis direction). Since two or more coordinates can have identical magnitude, the implementation must have rules to disambiguate this situation.

The rules should have as the first rule that rz wins over ry and rx, and the second rule that ry wins over rx. An implementation may choose other rules, but the rules must be deterministic and depend only on (rx,ry,rz).

The layer number (corresponding to a cube map face), the coordinate selections for sc, tc, rc, and the selection of derivatives, are determined by the major axis direction as specified in the following two tables.

Table 25. Cube map face and coordinate selection
Major Axis Direction | Layer Number | Cube Map Face | sc | tc | rc
--- | --- | --- | --- | --- | ---
+rx | 0 | Positive X | -rz | -ry | rx
-rx | 1 | Negative X | +rz | -ry | rx
+ry | 2 | Positive Y | +rx | +rz | ry
-ry | 3 | Negative Y | +rx | -rz | ry
+rz | 4 | Positive Z | +rx | -ry | rz
-rz | 5 | Negative Z | -rx | -ry | rz

Table 26. Cube map derivative selection
Major Axis Direction | ∂sc / ∂x | ∂sc / ∂y | ∂tc / ∂x | ∂tc / ∂y | ∂rc / ∂x | ∂rc / ∂y
--- | --- | --- | --- | --- | --- | ---
+rx | -∂rz / ∂x | -∂rz / ∂y | -∂ry / ∂x | -∂ry / ∂y | +∂rx / ∂x | +∂rx / ∂y
-rx | +∂rz / ∂x | +∂rz / ∂y | -∂ry / ∂x | -∂ry / ∂y | -∂rx / ∂x | -∂rx / ∂y
+ry | +∂rx / ∂x | +∂rx / ∂y | +∂rz / ∂x | +∂rz / ∂y | +∂ry / ∂x | +∂ry / ∂y
-ry | +∂rx / ∂x | +∂rx / ∂y | -∂rz / ∂x | -∂rz / ∂y | -∂ry / ∂x | -∂ry / ∂y
+rz | +∂rx / ∂x | +∂rx / ∂y | -∂ry / ∂x | -∂ry / ∂y | +∂rz / ∂x | +∂rz / ∂y
-rz | -∂rx / ∂x | -∂rx / ∂y | -∂ry / ∂x | -∂ry / ∂y | -∂rz / ∂x | -∂rz / ∂y

#### 15.5.5. Cube Map Coordinate Transformation

\[\begin{aligned} s_{\textit{face}} & = \frac{1}{2} \times \frac{s_c}{|r_c|} + \frac{1}{2} \\ t_{\textit{face}} & = \frac{1}{2} \times \frac{t_c}{|r_c|} + \frac{1}{2} \\ \end{aligned}\]

#### 15.5.6. Cube Map Derivative Transformation

\[\begin{aligned} \frac{\partial{s_{\textit{face}}}}{\partial{x}} &= \frac{\partial}{\partial{x}} \left ( \frac{1}{2} \times \frac{s_{c}}{|r_{c}|} + \frac{1}{2}\right ) \\ \frac{\partial{s_{\textit{face}}}}{\partial{x}} &= \frac{1}{2} \times \frac{\partial}{\partial{x}} \left ( \frac{s_{c}}{|r_{c}|} \right ) \\ \frac{\partial{s_{\textit{face}}}}{\partial{x}} &= \frac{1}{2} \times \left ( \frac{ |r_{c}| \times \partial{s_c}/\partial{x} -s_c \times {\partial{r_{c}}}/{\partial{x}}} {\left ( r_{c} \right )^2} \right ) \end{aligned}\]
\[\begin{aligned} \frac{\partial{s_{\textit{face}}}}{\partial{y}} &= \frac{1}{2} \times \left ( \frac{ |r_{c}| \times \partial{s_c}/\partial{y} -s_c \times {\partial{r_{c}}}/{\partial{y}}} {\left ( r_{c} \right )^2} \right )\\ \frac{\partial{t_{\textit{face}}}}{\partial{x}} &= \frac{1}{2} \times \left ( \frac{ |r_{c}| \times \partial{t_c}/\partial{x} -t_c \times {\partial{r_{c}}}/{\partial{x}}} {\left ( r_{c} \right )^2} \right ) \\ \frac{\partial{t_{\textit{face}}}}{\partial{y}} &= \frac{1}{2} \times \left ( \frac{ |r_{c}| \times \partial{t_c}/\partial{y} -t_c \times {\partial{r_{c}}}/{\partial{y}}} {\left ( r_{c} \right )^2} \right ) \end{aligned}\]

| editing-note (Bill) Note that we never revisited ARB_texture_cubemap after we introduced dependent texture fetches (ARB_fragment_program and ARB_fragment_shader). The derivatives of sface and tface are only valid for non-dependent texture fetches (pre OpenGL 2.0).

#### 15.5.7. Scale Factor Operation, Level-of-Detail Operation and Image Level(s) Selection

LOD selection can be either explicit (provided explicitly by the image instruction) or implicit (determined from a scale factor calculated from the derivatives). The implicit LOD selected can be queried using the SPIR-V instruction `OpImageQueryLod`, which gives access to the λ' and dl values, defined below. These values must be computed with `mipmapPrecisionBits` of accuracy and may be subject to implementation-specific maxima and minima for very large, out-of-range values.

##### Scale Factor Operation

The magnitude of the derivatives are calculated by:

  mux = |∂s/∂x| × wbase

  mvx = |∂t/∂x| × hbase

  mwx = |∂r/∂x| × dbase

  muy = |∂s/∂y| × wbase

  mvy = |∂t/∂y| × hbase

  mwy = |∂r/∂y| × dbase

where:

  ∂t/∂x = ∂t/∂y = 0 (for 1D images)

  ∂r/∂x = ∂r/∂y = 0 (for 1D, 2D or Cube images)

and:

  wbase = image.w

  hbase = image.h

  dbase = image.d

(for the `baseMipLevel`, from the image descriptor).

For corner-sampled images, the wbase, hbase, and dbase are instead:

  wbase = image.w - 1

  hbase = image.h - 1

  dbase = image.d - 1

A point sampled in screen space has an elliptical footprint in texture space. The minimum and maximum scale factors (ρmin, ρmax) should be the minor and major axes of this ellipse.

The scale factors ρx and ρy, calculated from the magnitude of the derivatives in x and y, are used to compute the minimum and maximum scale factors.

ρx and ρy may be approximated with functions fx and fy, subject to the following constraints:

\[\begin{aligned} & f_x \text{\ is\ continuous\ and\ monotonically\ increasing\ in\ each\ of\ } m_{ux}, m_{vx}, \text{\ and\ } m_{wx} \\ & f_y \text{\ is\ continuous\ and\ monotonically\ increasing\ in\ each\ of\ } m_{uy}, m_{vy}, \text{\ and\ } m_{wy} \end{aligned}\]
\[\begin{aligned} \max(|m_{ux}|, |m_{vx}|, |m_{wx}|) \leq f_{x} \leq \sqrt{2} (|m_{ux}| + |m_{vx}| + |m_{wx}|) \\ \max(|m_{uy}|, |m_{vy}|, |m_{wy}|) \leq f_{y} \leq \sqrt{2} (|m_{uy}| + |m_{vy}| + |m_{wy}|) \end{aligned}\]

| editing-note (Bill) For reviewers only - anticipating questions. We only support implicit derivatives for normalized texel coordinates. So we are documenting the derivatives in s,t,r (normalized texel coordinates) rather than u,v,w (unnormalized texel coordinates) as in OpenGL and OpenGL ES specifications. (I know, u,v,w is the way it has been documented since OpenGL V1.0.) Also there is no reason to have conditional application of wbase, hbase, dbase for rectangle textures either, since they do not support implicit derivatives.

The minimum and maximum scale factors (ρmin,ρmax) are determined by:

  ρmax = max(ρx, ρy)

  ρmin = min(ρx, ρy)

The ratio of anisotropy is determined by:

  η = min(ρmax/ρmin, maxAniso)

where:

  sampler.maxAniso = `maxAnisotropy` (from sampler descriptor)

  limits.maxAniso = `maxSamplerAnisotropy` (from physical device limits)

  maxAniso = min(sampler.maxAniso, limits.maxAniso)

If ρmax = ρmin = 0, then all the partial derivatives are zero, the fragment’s footprint in texel space is a point, and N should be treated as 1. If ρmax ≠ 0 and ρmin = 0 then all partial derivatives along one axis are zero, the fragment’s footprint in texel space is a line segment, and η should be treated as maxAniso. However, anytime the footprint is small in texel space the implementation may use a smaller value of η, even when ρmin is zero or close to zero. If either VkPhysicalDeviceFeatures::`samplerAnisotropy` or VkSamplerCreateInfo::`anisotropyEnable` are `VK_FALSE`, maxAniso is set to 1.

If η = 1, sampling is isotropic. If η > 1, sampling is anisotropic.

The sampling rate (N) is derived as:

  N = ⌈η⌉

An implementation may round N up to the nearest supported sampling rate. An implementation may use the value of N as an approximation of η.

##### Level-of-Detail Operation

The LOD parameter λ is computed as follows:

\[\begin{aligned} \lambda_{base}(x,y) & = \begin{cases} shaderOp.Lod & \text{(from optional SPIR-V operand)} \\ \log_2 \left ( \frac{\rho_{max}}{\eta} \right ) & \text{otherwise} \end{cases} \\ \lambda'(x,y) & = \lambda_{base} + \mathbin{clamp}(sampler.bias + shaderOp.bias,-maxSamplerLodBias,maxSamplerLodBias) \\ \lambda & = \begin{cases} lod_{max}, & \lambda' > lod_{max} \\ \lambda', & lod_{min} \leq \lambda' \leq lod_{max} \\ lod_{min}, & \lambda' < lod_{min} \\ \textit{undefined}, & lod_{min} > lod_{max} \end{cases} \end{aligned}\]

where:

\[\begin{aligned} sampler.bias & = mipLodBias & \text{(from sampler descriptor)} \\ shaderOp.bias & = \begin{cases} Bias & \text{(from optional SPIR-V operand)} \\ 0 & \text{otherwise} \end{cases} \\ sampler.lod_{min} & = minLod & \text{(from sampler descriptor)} \\ shaderOp.lod_{min} & = \begin{cases} MinLod & \text{(from optional SPIR-V operand)} \\ 0 & \text{otherwise} \end{cases} \\ \\ lod_{min} & = \max(sampler.lod_{min}, shaderOp.lod_{min}) \\ lod_{max} & = maxLod & \text{(from sampler descriptor)} \end{aligned}\]

and maxSamplerLodBias is the value of the VkPhysicalDeviceLimits feature `maxSamplerLodBias`.

##### Image Level(s) Selection

The image level(s) d, dhi, and dlo which texels are read from are determined by an image-level parameter dl, which is computed based on the LOD parameter, as follows:

\[\begin{aligned} d_{l} = \begin{cases} nearest(d'), & \text{mipmapMode is VK\_SAMPLER\_MIPMAP\_MODE\_NEAREST} \\ d', & \text{otherwise} \end{cases} \end{aligned}\]

where:

\[\begin{aligned} d' = level_{base} + \text{clamp}(\lambda, 0, q) \end{aligned}\]
\[\begin{aligned} nearest(d') & = \begin{cases} \left \lceil d' + 0.5\right \rceil - 1, & \text{preferred} \\ \left \lfloor d' + 0.5\right \rfloor, & \text{alternative} \end{cases} \end{aligned}\]

and:

  levelbase = `baseMipLevel`

  q = `levelCount` - 1

`baseMipLevel` and `levelCount` are taken from the `subresourceRange` of the image view.

If the sampler’s `mipmapMode` is `VK_SAMPLER_MIPMAP_MODE_NEAREST`, then the level selected is d = dl.

If the sampler’s `mipmapMode` is `VK_SAMPLER_MIPMAP_MODE_LINEAR`, two neighboring levels are selected:

\[\begin{aligned} d_{hi} & = \lfloor d_{l} \rfloor \\ d_{lo} & = min( d_{hi} + 1, q ) \\ \delta & = d_{l} - d_{hi} \end{aligned}\]

δ is the fractional value, quantized to the number of mipmap precision bits, used for linear filtering between levels.

#### 15.5.8. (s,t,r,q,a) to (u,v,w,a) Transformation

The normalized texel coordinates are scaled by the image level dimensions and the array layer is selected.

This transformation is performed once for each level used in filtering (either d, or dhi and dlo).

\[\begin{aligned} u(x,y) & = s(x,y) \times width_{scale} + \Delta_i\\ v(x,y) & = \begin{cases} 0 & \text{for 1D images} \\ t(x,y) \times height_{scale} + \Delta_j & \text{otherwise} \end{cases} \\ w(x,y) & = \begin{cases} 0 & \text{for 2D or Cube images} \\ r(x,y) \times depth_{scale} + \Delta_k & \text{otherwise} \end{cases} \\ \\ a(x,y) & = \begin{cases} a(x,y) & \text{for array images} \\ 0 & \text{otherwise} \end{cases} \end{aligned}\]

where:

  widthscale = widthlevel

  heightscale = heightlevel

  depthscale = depthlevel

for conventional images, and:

  widthscale = widthlevel - 1

  heightscale = heightlevel - 1

  depthscale = depthlevel - 1

for corner-sampled images.

and where (Δi, Δj, Δk) are taken from the image instruction if it includes a `ConstOffset` or `Offset` operand, otherwise they are taken to be zero.

Operations then proceed to Unnormalized Texel Coordinate Operations.

### 15.6. Unnormalized Texel Coordinate Operations

#### 15.6.1. (u,v,w,a) to (i,j,k,l,n) Transformation And Array Layer Selection

The unnormalized texel coordinates are transformed to integer texel coordinates relative to the selected mipmap level.

The layer index l is computed as:

  l = clamp(RNE(a), 0, `layerCount` - 1) + `baseArrayLayer`

where `layerCount` is the number of layers in the image subresource range of the image view, `baseArrayLayer` is the first layer from the subresource range, and where:

\[\begin{aligned} \mathbin{RNE}(a) & = \begin{cases} \mathbin{roundTiesToEven}(a) & \text{preferred, from IEEE Std 754-2008 Floating-Point Arithmetic} \\ \left \lfloor a + 0.5 \right \rfloor & \text{alternative} \end{cases} \end{aligned}\]

The sample index n is assigned the value zero.

Nearest filtering (`VK_FILTER_NEAREST`) computes the integer texel coordinates that the unnormalized coordinates lie within:

\[\begin{aligned} i &= \lfloor u + shift \rfloor \\ j &= \lfloor v + shift \rfloor \\ k &= \lfloor w + shift \rfloor \end{aligned}\]

where:

  shift = 0.0

for conventional images, and:

  shift = 0.5

for corner-sampled images.

Linear filtering (`VK_FILTER_LINEAR`) computes a set of neighboring coordinates which bound the unnormalized coordinates. The integer texel coordinates are combinations of i0 or i1, j0 or j1, k0 or k1, as well as weights α, β, and γ.

\[\begin{aligned} i_0 &= \lfloor u - shift \rfloor \\ i_1 &= i_0 + 1 \\ j_0 &= \lfloor v - shift \rfloor \\ j_1 &= j_0 + 1 \\ k_0 &= \lfloor w - shift \rfloor k_1 &= k_0 + 1 \end{aligned}\]
\[\begin{aligned} \alpha &= \mathbin{frac}\left(u - shift\right) \\[1em] \beta &= \mathbin{frac}\left(v - shift\right) \\[1em] \gamma &= \mathbin{frac}\left(w - shift\right) \end{aligned}\]

where:

  shift = 0.5

for conventional images, and:

  shift = 0.0

for corner-sampled images, and where:

\[\mathbin{frac}(x) = x - \lfloor x \rfloor\]

where the number of fraction bits retained is specified by `VkPhysicalDeviceLimits`::`subTexelPrecisionBits`.

Cubic filtering (`VK_FILTER_CUBIC_EXT`) computes a set of neighboring coordinates which bound the unnormalized coordinates. The integer texel coordinates are combinations of i0, i1, i2 or i3, j0, j1, j2 or j3, k0, k1, k2 or k3, as well as weights α, β, and γ.

\[\begin{aligned} i_{0} & = {\left \lfloor {u - \frac{3}{2}} \right \rfloor} & i_{1} & = i_{0} + 1 & i_{2} & = i_{1} + 1 & i_{3} & = i_{2} + 1 \\[1em] j_{0} & = {\left \lfloor {v - \frac{3}{2}} \right \rfloor} & j_{1} & = j_{0} + 1 & j_{2} & = j_{1} + 1 & j_{3} & = j_{2} + 1 \\[1em] k_{0} & = {\left \lfloor {w - \frac{3}{2}} \right \rfloor} & k_{1} & = k_{0} + 1 & k_{2} & = k_{1} + 1 & k_{3} & = k_{2} + 1 \end{aligned}\]
\[\begin{aligned} \alpha &= \mathbin{frac}\left(u - \frac{1}{2}\right) \\[1em] \beta &= \mathbin{frac}\left(v - \frac{1}{2}\right) \\[1em] \gamma &= \mathbin{frac}\left(w - \frac{1}{2}\right) \end{aligned}\]

where:

\[\mathbin{frac}(x) = x - \lfloor x \rfloor\]

where the number of fraction bits retained is specified by `VkPhysicalDeviceLimits`::`subTexelPrecisionBits`.

### 15.7. Integer Texel Coordinate Operations

Integer texel coordinate operations may supply a LOD which texels are to be read from or written to using the optional SPIR-V operand `Lod`. If the `Lod` is provided then it must be an integer.

The image level selected is:

\[\begin{aligned} d & = level_{base} + \begin{cases} Lod & \text{(from optional SPIR-V operand)} \\ 0 & \text{otherwise} \end{cases} \\ \end{aligned}\]

If d does not lie in the range [`baseMipLevel`, `baseMipLevel` + `levelCount`) then any values fetched are undefined, and any writes are discarded.

### 15.8. Image Sample Operations

#### 15.8.1. Wrapping Operation

`Cube` images ignore the wrap modes specified in the sampler. Instead, if `VK_FILTER_NEAREST` is used within a mip level then `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE` is used, and if `VK_FILTER_LINEAR` is used within a mip level then sampling at the edges is performed as described earlier in the Cube map edge handling section.

The first integer texel coordinate i is transformed based on the `addressModeU` parameter of the sampler.

\[\begin{aligned} i &= \begin{cases} i \bmod size & \text{for repeat} \\ (size - 1) - \mathbin{mirror} ((i \bmod (2 \times size)) - size) & \text{for mirrored repeat} \\ \mathbin{clamp}(i,0,size-1) & \text{for clamp to edge} \\ \mathbin{clamp}(i,-1,size) & \text{for clamp to border} \\ \mathbin{clamp}(\mathbin{mirror}(i),0,size-1) & \text{for mirror clamp to edge} \end{cases} \end{aligned}\]

where:

\[\begin{aligned} & \mathbin{mirror}(n) = \begin{cases} n & \text{for}\ n \geq 0 \\ -(1+n) & \text{otherwise} \end{cases} \end{aligned}\]

j (for 2D and Cube image) and k (for 3D image) are similarly transformed based on the `addressModeV` and `addressModeW` parameters of the sampler, respectively.

#### 15.8.2. Texel Gathering

SPIR-V instructions with `Gather` in the name return a vector derived from 4 texels in the base level of the image view. The rules for the `VK_FILTER_LINEAR` minification filter are applied to identify the four selected texels. Each texel is then converted to an RGBA value according to conversion to RGBA and then swizzled. A four-component vector is then assembled by taking the component indicated by the `Component` value in the instruction from the swizzled color value of the four texels. If the operation does not use the `ConstOffsets` image operand then the four texels form the 2 × 2 rectangle used for texture filtering:

\[\begin{aligned} \tau[R] &= \tau_{i0j1}[level_{base}][comp] \\ \tau[G] &= \tau_{i1j1}[level_{base}][comp] \\ \tau[B] &= \tau_{i1j0}[level_{base}][comp] \\ \tau[A] &= \tau_{i0j0}[level_{base}][comp] \end{aligned}\]

If the operation does use the `ConstOffsets` image operand then the offsets allow a custom filter to be defined:

\[\begin{aligned} \tau[R] &= \tau_{i0j0 + \Delta_0}[level_{base}][comp] \\ \tau[G] &= \tau_{i0j0 + \Delta_1}[level_{base}][comp] \\ \tau[B] &= \tau_{i0j0 + \Delta_2}[level_{base}][comp] \\ \tau[A] &= \tau_{i0j0 + \Delta_3}[level_{base}][comp] \end{aligned}\]

where:

\[\begin{aligned} \tau[level_{base}][comp] &= \begin{cases} \tau[level_{base}][R], & \text{for}\ comp = 0 \\ \tau[level_{base}][G], & \text{for}\ comp = 1 \\ \tau[level_{base}][B], & \text{for}\ comp = 2 \\ \tau[level_{base}][A], & \text{for}\ comp = 3 \end{cases}\\ comp & \,\text{from SPIR-V operand Component} \end{aligned}\]

`OpImage`*`Gather` must not be used on a sampled image with sampler Y′CBCR conversion enabled.

#### 15.8.3. Texel Filtering

Texel filtering is first performed for each level (either d or dhi and dlo).

If λ is less than or equal to zero, the texture is said to be magnified, and the filter mode within a mip level is selected by the `magFilter` in the sampler. If λ is greater than zero, the texture is said to be minified, and the filter mode within a mip level is selected by the `minFilter` in the sampler.

##### Texel Nearest Filtering

Within a mip level, `VK_FILTER_NEAREST` filtering selects a single value using the (i, j, k) texel coordinates, with all texels taken from layer l.

\[\begin{aligned} \tau[level] &= \begin{cases} \tau_{ijk}[level], & \text{for 3D image} \\ \tau_{ij}[level], & \text{for 2D or Cube image} \\ \tau_{i}[level], & \text{for 1D image} \end{cases} \end{aligned}\]

##### Texel Linear Filtering

Within a mip level, `VK_FILTER_LINEAR` filtering combines 8 (for 3D), 4 (for 2D or Cube), or 2 (for 1D) texel values, together with their linear weights. The linear weights are derived from the fractions computed earlier:

\[\begin{aligned} w_{i_0} &= (1-\alpha) \\ w_{i_1} &= (\alpha) \\ w_{j_0} &= (1-\beta) \\ w_{j_1} &= (\beta) \\ w_{k_0} &= (1-\gamma) \\ w_{k_1} &= (\gamma) \end{aligned}\]

The values of multiple texels, together with their weights, are combined to produce a filtered value.

The VkSamplerReductionModeCreateInfo::`reductionMode` can control the process by which multiple texels, together with their weights, are combined to produce a filtered texture value.

When the `reductionMode` is set (explicitly or implicitly) to `VK_SAMPLER_REDUCTION_MODE_WEIGHTED_AVERAGE`, a weighted average is computed:

\[\begin{aligned} \tau_{3D} &= \sum_{k=k_0}^{k_1}\sum_{j=j_0}^{j_1}\sum_{i=i_0}^{i_1}(w_{i})(w_{j})(w_{k})\tau_{ijk} \\ \tau_{2D} &= \sum_{j=j_0}^{j_1}\sum_{i=i_0}^{i_1}(w_{i})(w_{j})\tau_{ij} \\ \tau_{1D} &= \sum_{i=i_0}^{i_1}(w_{i})\tau_{i} \end{aligned}\]

However, if the reduction mode is `VK_SAMPLER_REDUCTION_MODE_MIN` or `VK_SAMPLER_REDUCTION_MODE_MAX`, the process operates on the above set of multiple texels, together with their weights, computing a component-wise minimum or maximum, respectively, of the components of the set of texels with non-zero weights.

##### Texel Cubic Filtering

Within a mip level, `VK_FILTER_CUBIC_EXT`, filtering computes a weighted average of 64 (for 3D), 16 (for 2D), or 4 (for 1D) texel values, together with their Catmull-Rom weights.

Catmull-Rom weights are derived from the fractions computed earlier.

\[\begin{aligned} \begin{bmatrix} w_{i_0}\phantom{,} w_{i_1}\phantom{,} w_{i_2}\phantom{,} w_{i_3} \end{bmatrix} = \frac{1}{2} \begin{bmatrix} 1 & \alpha & \alpha^2 & \alpha^3 \end{bmatrix} \begin{bmatrix} \phantom{-}0 & \phantom{-}2 & \phantom{-}0 & \phantom{-}0 \\ -1 & \phantom{-}0 & \phantom{-}1 & \phantom{-}0 \\ \phantom{-}2 & -5 & \phantom{-}4 & -1 \\ -1 & \phantom{-}3 & -3 & \phantom{-}1 \end{bmatrix} \\ \begin{bmatrix} w_{j_0}\phantom{,} w_{j_1}\phantom{,} w_{j_2}\phantom{,} w_{j_3} \end{bmatrix} = \frac{1}{2} \begin{bmatrix} 1 & \beta & \beta^2 & \beta^3 \end{bmatrix} \begin{bmatrix} \phantom{-}0 & \phantom{-}2 & \phantom{-}0 & \phantom{-}0 \\ -1 & \phantom{-}0 & \phantom{-}1 & \phantom{-}0 \\ \phantom{-}2 & -5 & \phantom{-}4 & -1 \\ -1 & \phantom{-}3 & -3 & \phantom{-}1 \end{bmatrix} \\ \begin{bmatrix} w_{k_0}\phantom{,} w_{k_1}\phantom{,} w_{k_2}\phantom{,} w_{k_3} \end{bmatrix} = \frac{1}{2} \begin{bmatrix} 1 & \gamma & \gamma^2 & \gamma^3 \end{bmatrix} \begin{bmatrix} \phantom{-}0 & \phantom{-}2 & \phantom{-}0 & \phantom{-}0 \\ -1 & \phantom{-}0 & \phantom{-}1 & \phantom{-}0 \\ \phantom{-}2 & -5 & \phantom{-}4 & -1 \\ -1 & \phantom{-}3 & -3 & \phantom{-}1 \end{bmatrix} \end{aligned}\]

The values of multiple texels, together with their weights, are combined to produce a filtered value.

The VkSamplerReductionModeCreateInfo::`reductionMode` can control the process by which multiple texels, together with their weights, are combined to produce a filtered texture value.

When the `reductionMode` is set (explicitly or implicitly) to `VK_SAMPLER_REDUCTION_MODE_WEIGHTED_AVERAGE`, a weighted average is computed:

\[\begin{aligned} \tau_{3D} &= \sum_{k=j_0}^{k_3}\sum_{j=j_0}^{j_3}\sum_{i=i_0}^{i_3}(w_{i})(w_{j})(w_{k})\tau_{ijk} \\ \tau_{2D} &= \sum_{j=j_0}^{j_3}\sum_{i=i_0}^{i_3}(w_{i})(w_{j})\tau_{ij} \\ \tau_{1D} &= \sum_{i=i_0}^{i_3}(w_{i})\tau_{i} \end{aligned}\]

However, if the reduction mode is `VK_SAMPLER_REDUCTION_MODE_MIN` or `VK_SAMPLER_REDUCTION_MODE_MAX`, the process operates on the above set of multiple texels, together with their weights, computing a component-wise minimum or maximum, respectively, of the components of the set of texels with non-zero weights.

##### Texel Mipmap Filtering

`VK_SAMPLER_MIPMAP_MODE_NEAREST` filtering returns the value of a single mipmap level,

τ = τ[d].

`VK_SAMPLER_MIPMAP_MODE_LINEAR` filtering combines the values of multiple mipmap levels (τ[hi] and τ[lo]), together with their linear weights.

The linear weights are derived from the fraction computed earlier:

\[\begin{aligned} w_{hi} &= (1-\delta) \\ w_{lo} &= (\delta) \\ \end{aligned}\]

The values of multiple mipmap levels, together with their weights, are combined to produce a final filtered value.

The VkSamplerReductionModeCreateInfo::`reductionMode` can control the process by which multiple texels, together with their weights, are combined to produce a filtered texture value.

When the `reductionMode` is set (explicitly or implicitly) to `VK_SAMPLER_REDUCTION_MODE_WEIGHTED_AVERAGE`, a weighted average is computed:

\[\begin{aligned} \tau &= (w_{hi})\tau[hi]+(w_{lo})\tau[lo] \end{aligned}\]

##### Texel Anisotropic Filtering

Anisotropic filtering is enabled by the `anisotropyEnable` in the sampler. When enabled, the image filtering scheme accounts for a degree of anisotropy.

The particular scheme for anisotropic texture filtering is implementation dependent. Implementations should consider the `magFilter`, `minFilter` and `mipmapMode` of the sampler to control the specifics of the anisotropic filtering scheme used. In addition, implementations should consider `minLod` and `maxLod` of the sampler.

The following describes one particular approach to implementing anisotropic filtering for the 2D Image case, implementations may choose other methods:

Given a `magFilter`, `minFilter` of `VK_FILTER_LINEAR` and a `mipmapMode` of `VK_SAMPLER_MIPMAP_MODE_NEAREST`:

Instead of a single isotropic sample, N isotropic samples are be sampled within the image footprint of the image level d to approximate an anisotropic filter. The sum τ2Daniso is defined using the single isotropic τ2D(u,v) at level d.

\[\begin{aligned} \tau_{2Daniso} & = \frac{1}{N}\sum_{i=1}^{N} {\tau_{2D}\left ( u \left ( x - \frac{1}{2} + \frac{i}{N+1} , y \right ), \left ( v \left (x-\frac{1}{2}+\frac{i}{N+1} \right ), y \right ) \right )}, & \text{when}\ \rho_{x} > \rho_{y} \\ \tau_{2Daniso} &= \frac{1}{N}\sum_{i=1}^{N} {\tau_{2D}\left ( u \left ( x, y - \frac{1}{2} + \frac{i}{N+1} \right ), \left ( v \left (x,y-\frac{1}{2}+\frac{i}{N+1} \right ) \right ) \right )}, & \text{when}\ \rho_{y} \geq \rho_{x} \end{aligned}\]

When VkSamplerReductionModeCreateInfo::`reductionMode` is set to `VK_SAMPLER_REDUCTION_MODE_WEIGHTED_AVERAGE`, the above summation is used. However, if the reduction mode is `VK_SAMPLER_REDUCTION_MODE_MIN` or `VK_SAMPLER_REDUCTION_MODE_MAX`, the process operates on the above values, together with their weights, computing a component-wise minimum or maximum, respectively, of the components of the values with non-zero weights.

### 15.9. Texel Footprint Evaluation

The SPIR-V instruction `OpImageSampleFootprintNV` evaluates the set of texels from a single mip level that would be accessed during a texel filtering operation. In addition to the inputs that would be accepted by an equivalent `OpImageSample`* instruction, `OpImageSampleFootprintNV` accepts two additional inputs. The `Granularity` input is an integer identifying the size of texel groups used to evaluate the footprint. Each bit in the returned footprint mask corresponds to an aligned block of texels whose size is given by the following table:

Table 27. Texel footprint granularity values
`Granularity` | `Dim` = 2D | `Dim` = 3D
--- | --- | ---
0 | unsupported | unsupported
1 | 2x2 | 2x2x2
2 | 4x2 | unsupported
3 | 4x4 | 4x4x2
4 | 8x4 | unsupported
5 | 8x8 | unsupported
6 | 16x8 | unsupported
7 | 16x16 | unsupported
8 | unsupported | unsupported
9 | unsupported | unsupported
10 | unsupported | 16x16x16
11 | 64x64 | 32x16x16
12 | 128x64 | 32x32x16
13 | 128x128 | 32x32x32
14 | 256x128 | 64x32x32
15 | 256x256 | unsupported

The `Coarse` input is used to select between the two mip levels that may be accessed during texel filtering when using a `mipmapMode` of `VK_SAMPLER_MIPMAP_MODE_LINEAR`. When filtering between two mip levels, a `Coarse` value of `true` requests the footprint in the lower-resolution mip level (higher level number), while `false` requests the footprint in the higher-resolution mip level. If texel filtering would access only a single mip level, the footprint in that level would be returned when `Coarse` is set to `false`; an empty footprint would be returned when `Coarse` is set to `true`.

The footprint for `OpImageSampleFootprintNV` is returned in a structure with six members:

- The first member is a boolean value that is true if the texel filtering operation would access only a single mip level.

- The second member is a two- or three-component integer vector holding the footprint anchor location. For two-dimensional images, the returned components are in units of eight texel groups. For three-dimensional images, the returned components are in units of four texel groups.

- The third member is a two- or three-component integer vector holding a footprint offset relative to the anchor. All returned components are in units of texel groups.

- The fourth member is a two-component integer vector mask, which holds a bitfield identifying the set of texel groups in an 8x8 or 4x4x4 neighborhood relative to the anchor and offset.

- The fifth member is an integer identifying the mip level containing the footprint identified by the anchor, offset, and mask.

- The sixth member is an integer identifying the granularity of the returned footprint.

For footprints in two-dimensional images (`Dim2D`), the mask returned by `OpImageSampleFootprintNV` indicates whether each texel group in a 8x8 local neighborhood of texel groups would have one or more texels accessed during texel filtering. In the mask, the texel group with local group coordinates \((lgx,lgy)\) is considered covered if and only if

\[\begin{aligned} 0 \neq ((mask.x + (mask.y << 32)) \text{ \& } (1 << (lgy \times 8 + lgx))) \end{aligned}\]

where:

- \(0<=lgx<8\) and \(0<=lgy<8\); and

- \(mask\) is the returned two-component mask.

The local group with coordinates \((lgx,lgy)\) in the mask is considered covered if and only if the texel filtering operation would access one or more texels \(\tau_{ij}\) in the returned miplevel where:

\[\begin{aligned} i0 & = \begin{cases} gran.x \times (8 \times anchor.x + lgx), & \text{if } lgx + offset.x < 8 \\ gran.x \times (8 \times (anchor.x - 1) + lgx), & \text{otherwise} \end{cases} \\ i1 & = i0 + gran.x - 1 \\ j0 & = \begin{cases} gran.y \times (8 \times anchor.y + lgy), & \text{if } lgy + offset.y < 8 \\ gran.y \times (8 \times (anchor.y - 1) + lgy), & otherwise \end{cases} \\ j1 & = j0 + gran.y - 1 \end{aligned}\]

and

- \(i0<=i<=i1\) and \(j0<=j<=j1\);

- \(gran\) is a two-component vector holding the width and height of the texel group identified by the granularity;

- \(anchor\) is the returned two-component anchor vector; and

- \(offset\) is the returned two-component offset vector.

For footprints in three-dimensional images (`Dim3D`), the mask returned by `OpImageSampleFootprintNV` indicates whether each texel group in a 4x4x4 local neighborhood of texel groups would have one or more texels accessed during texel filtering. In the mask, the texel group with local group coordinates \((lgx,lgy,lgz)\), is considered covered if and only if:

\[\begin{aligned} 0 \neq ((mask.x + (mask.y << 32)) \text{ \& } (1 << (lgz \times 16 + lgy \times 4 + lgx))) \end{aligned}\]

where:

- \(0<=lgx<4\), \(0<=lgy<4\), and \(0<=lgz<4\); and

- \(mask\) is the returned two-component mask.

The local group with coordinates \((lgx,lgy,lgz)\) in the mask is considered covered if and only if the texel filtering operation would access one or more texels \(\tau_{ijk}\) in the returned miplevel where:

\[\begin{aligned} i0 & = \begin{cases} gran.x \times (4 \times anchor.x + lgx), & \text{if } lgx + offset.x < 4 \\ gran.x \times (4 \times (anchor.x - 1) + lgx), & \text{otherwise} \end{cases} \\ i1 & = i0 + gran.x - 1 \\ j0 & = \begin{cases} gran.y \times (4 \times anchor.y + lgy), & \text{if } lgy + offset.y < 4 \\ gran.y \times (4 \times (anchor.y - 1) + lgy), & otherwise \end{cases} \\ j1 & = j0 + gran.y - 1 \\ k0 & = \begin{cases} gran.z \times (4 \times anchor.z + lgz), & \text{if } lgz + offset.z < 4 \\ gran.z \times (4 \times (anchor.z - 1) + lgz), & otherwise \end{cases} \\ k1 & = k0 + gran.z - 1 \end{aligned}\]

and

- \(i0<=i<=i1\), \(j0<=j<=j1\), \(k0<=k<=k1\);

- \(gran\) is a three-component vector holding the width, height, and depth of the texel group identified by the granularity;

- \(anchor\) is the returned three-component anchor vector; and

- \(offset\) is the returned three-component offset vector.

If the sampler used by `OpImageSampleFootprintNV` enables anisotropic texel filtering via `anisotropyEnable`, it is possible that the set of texel groups accessed in a mip level may be too large to be expressed using an 8x8 or 4x4x4 mask using the granularity requested in the instruction. In this case, the implementation uses a texel group larger than the requested granularity. When a larger texel group size is used, `OpImageSampleFootprintNV` returns an integer granularity value that can be interpreted in the same manner as the granularity value provided to the instruction to determine the texel group size used. If anisotropic texel filtering is disabled in the sampler, or if an anisotropic footprint can be represented as an 8x8 or 4x4x4 mask with the requested granularity, `OpImageSampleFootprintNV` will use the requested granularity as-is and return a granularity value of zero.

`OpImageSampleFootprintNV` supports only two- and three-dimensional image accesses (`Dim2D` and `Dim3D`) and the footprint returned is undefined if a sampler uses an addressing mode other than `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`.

### 15.10. Image Operation Steps

Each step described in this chapter is performed by a subset of the image instructions:

- Texel Input Validation Operations, Format Conversion, Texel Replacement, Conversion to RGBA, and Component Swizzle: Performed by all instructions except `OpImageWrite`.

- Depth Comparison: Performed by `OpImage`*`Dref` instructions.

- All Texel output operations: Performed by `OpImageWrite`.

- Projection: Performed by all `OpImage`*`Proj` instructions.

- Derivative Image Operations, Cube Map Operations, Scale Factor Operation, Level-of-Detail Operation and Image Level(s) Selection, and Texel Anisotropic Filtering: Performed by all `OpImageSample`* and `OpImageSparseSample`* instructions.

- (s,t,r,q,a) to (u,v,w,a) Transformation, Wrapping, and (u,v,w,a) to (i,j,k,l,n) Transformation And Array Layer Selection: Performed by all `OpImageSample`, `OpImageSparseSample`, and `OpImage`*`Gather` instructions.

- Texel Gathering: Performed by `OpImage`*`Gather` instructions.

- Texel Footprint Evaluation: Performed by `OpImageSampleFootprint` instructions.

- Texel Filtering: Performed by all `OpImageSample`* and `OpImageSparseSample`* instructions.

- Sparse Residency: Performed by all `OpImageSparse`* instructions.

## 16. Fragment Density Map Operations

### 16.1. Fragment Density Map Operations Overview

When a fragment is generated in a render pass that has a fragment density map attachment, its area is determined by the properties of the local framebuffer region that the fragment occupies. The framebuffer is divided into a uniform grid of these local regions, and their fragment area property is derived from the density map with the following operations:

- Fetch density value

  - Component swizzle

  - Component mapping

- Fragment area conversion

  - Fragment area filter

  - Fragment area clamp

### 16.2. Fetch Density Value

Each local framebuffer region at center coordinate (x,y) fetches a texel from the fragment density map at integer coordinates:

  \(i = \lfloor{\frac{x}{fragmentDensityTexelSize_{width}}}\rfloor\)

  \(j = \lfloor{\frac{y}{fragmentDensityTexelSize_{height}}}\rfloor\)

Where the size of each region in the framebuffer is:

  \(fragmentDensityTexelSize'_{width} = {2^{\lceil{\log_2(\frac{framebuffer_{width}}{fragmentDensityMap_{width}})}\rceil}}\)

  \(fragmentDensityTexelSize'_{height} = {2^{\lceil{\log_2(\frac{framebuffer_{height}}{fragmentDensityMap_{height}})}\rceil}}\)

This region is subject to the limits in `VkPhysicalDeviceFragmentDensityMapPropertiesEXT` and therefore the final region size is clamped:

  \(fragmentDensityTexelSize_{width} = \mathbin{clamp}(fragmentDensityTexelSize'_{width},minFragmentDensityTexelSize_{width},maxFragmentDensityTexelSize_{width})\)

  \(fragmentDensityTexelSize_{height} = \mathbin{clamp}(fragmentDensityTexelSize'_{height},minFragmentDensityTexelSize_{height},maxFragmentDensityTexelSize_{height})\)

When multiview is enabled for the render pass and the fragment density map attachment view was created with `layerCount` greater than `1`, the density map layer that the texel is fetched from is:

  \(layer = baseArrayLayer + ViewIndex\)

Otherwise:

  \(layer = baseArrayLayer\)

The texel fetched from the density map at (i,j,layer) is next converted to density with the following operations.

#### 16.2.1. Component Swizzle

The `components` member of VkImageViewCreateInfo is applied to the fetched texel as defined in Image component swizzle.

#### 16.2.2. Component Mapping

The swizzled texel’s components are mapped to a density value:

  \(densityValue_{xy} = (C'_{r},C'_{g})\)

### 16.3. Fragment Area Conversion

Fragment area for the framebuffer region is undefined if the density fetched is not a normalized floating-point value greater than `0.0`. Otherwise, the fetched fragment area for that region is derived as:

  \(fragmentArea_{wh} = \frac{1.0}{densityValue_{xy}}\)

#### 16.3.1. Fragment Area Filter

Optionally, the implementation may fetch additional density map texels in an implementation defined window around (i,j). The texels follow the standard conversion steps up to and including fragment area conversion.

A single fetched fragment area for the framebuffer region is chosen by the implementation and must have an area between the min and max areas of the fetched set.

#### 16.3.2. Fragment Area Clamp

The implementation may clamp the fetched fragment area to one that it supports. The clamped fragment area must have a size less than or equal to the original fetched value. Implementations may vary the supported set of fragment areas per framebuffer region. Fragment area (1,1) must always be in the supported set.

| Note For example, if the fetched fragment area is (1,4) but the implementation only supports areas of {(1,1),(2,2)}, it could choose to clamp the area to (2,2) since it has the same size as (1,4). While this would produce fragments that have lower quality strictly in the x-axis, the overall density is maintained.

The clamped fragment area is assigned to the corresponding framebuffer region.

## 17. Queries

Queries provide a mechanism to return information about the processing of a sequence of Vulkan commands. Query operations are asynchronous, and as such, their results are not returned immediately. Instead, their results, and their availability status are stored in a Query Pool. The state of these queries can be read back on the host, or copied to a buffer object on the device.

The supported query types are Occlusion Queries, Pipeline Statistics Queries, and Timestamp Queries. Performance Queries are also supported if the associated extension is available. Intel performance queries are also supported if the associated extension is available.

### 17.1. Query Pools

Queries are managed using query pool objects. Each query pool is a collection of a specific number of queries of a particular type.

Query pools are represented by `VkQueryPool` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkQueryPool)

To create a query pool, call:

    VkResult vkCreateQueryPool(
        VkDevice                                    device,
        const VkQueryPoolCreateInfo*                pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkQueryPool*                                pQueryPool);

- `device` is the logical device that creates the query pool.

- `pCreateInfo` is a pointer to a `VkQueryPoolCreateInfo` structure containing the number and type of queries to be managed by the pool.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pQueryPool` is a pointer to a VkQueryPool handle in which the resulting query pool object is returned.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkQueryPoolCreateInfo structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pQueryPool` must be a valid pointer to a VkQueryPool handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkQueryPoolCreateInfo` structure is defined as:

    typedef struct VkQueryPoolCreateInfo {
        VkStructureType                  sType;
        const void*                      pNext;
        VkQueryPoolCreateFlags           flags;
        VkQueryType                      queryType;
        uint32_t                         queryCount;
        VkQueryPipelineStatisticFlags    pipelineStatistics;
    } VkQueryPoolCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `queryType` is a VkQueryType value specifying the type of queries managed by the pool.

- `queryCount` is the number of queries managed by the pool.

- `pipelineStatistics` is a bitmask of VkQueryPipelineStatisticFlagBits specifying which counters will be returned in queries on the new pool, as described below in Pipeline Statistics Queries.

`pipelineStatistics` is ignored if `queryType` is not `VK_QUERY_TYPE_PIPELINE_STATISTICS`.

Valid Usage

- If the pipeline statistics queries feature is not enabled, `queryType` must not be `VK_QUERY_TYPE_PIPELINE_STATISTICS`

- If `queryType` is `VK_QUERY_TYPE_PIPELINE_STATISTICS`, `pipelineStatistics` must be a valid combination of VkQueryPipelineStatisticFlagBits values

- If `queryType` is `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR`, the `pNext` chain must include a structure of type VkQueryPoolPerformanceCreateInfoKHR

- `queryCount` must be greater than 0

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_QUERY_POOL_CREATE_INFO`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkQueryPoolPerformanceCreateInfoKHR or VkQueryPoolPerformanceQueryCreateInfoINTEL

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be `0`

- `queryType` must be a valid VkQueryType value

    typedef VkFlags VkQueryPoolCreateFlags;

`VkQueryPoolCreateFlags` is a bitmask type for setting a mask, but is currently reserved for future use.

The `VkQueryPoolPerformanceCreateInfoKHR` structure is defined as:

    typedef struct VkQueryPoolPerformanceCreateInfoKHR {
        VkStructureType    sType;
        const void*        pNext;
        uint32_t           queueFamilyIndex;
        uint32_t           counterIndexCount;
        const uint32_t*    pCounterIndices;
    } VkQueryPoolPerformanceCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `queueFamilyIndex` is the queue family index to create this performance query pool for.

- `counterIndexCount` is size of the `pCounterIndices` array.

- `pCounterIndices` is the array of indices into the vkEnumeratePhysicalDeviceQueueFamilyPerformanceQueryCountersKHR::`pCounters` to enable in this performance query pool.

Valid Usage

- `queueFamilyIndex` must be a valid queue family index of the device

- The `performanceCounterQueryPools` feature must be enabled

- Each element of `pCounterIndices` must be in the range of counters reported by `vkEnumeratePhysicalDeviceQueueFamilyPerformanceQueryCountersKHR` for the queue family specified in `queueFamilyIndex`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_QUERY_POOL_PERFORMANCE_CREATE_INFO_KHR`

- `pCounterIndices` must be a valid pointer to an array of `counterIndexCount` `uint32_t` values

- `counterIndexCount` must be greater than `0`

To query the number of passes required to query a performance query pool on a physical device, call:

    void vkGetPhysicalDeviceQueueFamilyPerformanceQueryPassesKHR(
        VkPhysicalDevice                            physicalDevice,
        const VkQueryPoolPerformanceCreateInfoKHR*  pPerformanceQueryCreateInfo,
        uint32_t*                                   pNumPasses);

- `physicalDevice` is the handle to the physical device whose queue family performance query counter properties will be queried.

- `pPerformanceQueryCreateInfo` is a pointer to a `VkQueryPoolPerformanceCreateInfoKHR` of the performance query that is to be created.

- `pNumPasses` is a pointer to an integer related to the number of passes required to query the performance query pool, as described below.

The `pPerformanceQueryCreateInfo` member `VkQueryPoolPerformanceCreateInfoKHR`::`queueFamilyIndex` must be a queue family of `physicalDevice`. The number of passes required to capture the counters specified in the `pPerformanceQueryCreateInfo` member `VkQueryPoolPerformanceCreateInfoKHR`::`pCounters` is returned in `pNumPasses`.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pPerformanceQueryCreateInfo` must be a valid pointer to a valid VkQueryPoolPerformanceCreateInfoKHR structure

- `pNumPasses` must be a valid pointer to a `uint32_t` value

To destroy a query pool, call:

    void vkDestroyQueryPool(
        VkDevice                                    device,
        VkQueryPool                                 queryPool,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that destroys the query pool.

- `queryPool` is the query pool to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage

- All submitted commands that refer to `queryPool` must have completed execution

- If `VkAllocationCallbacks` were provided when `queryPool` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `queryPool` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `queryPool` is not VK_NULL_HANDLE, `queryPool` must be a valid VkQueryPool handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- If `queryPool` is a valid handle, it must have been created, allocated, or retrieved from `device`

Host Synchronization

- Host access to `queryPool` must be externally synchronized

Possible values of VkQueryPoolCreateInfo::`queryType`, specifying the type of queries managed by the pool, are:

    typedef enum VkQueryType {
        VK_QUERY_TYPE_OCCLUSION = 0,
        VK_QUERY_TYPE_PIPELINE_STATISTICS = 1,
        VK_QUERY_TYPE_TIMESTAMP = 2,
        VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT = 1000028004,
        VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR = 1000116000,
        VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_KHR = 1000165000,
        VK_QUERY_TYPE_ACCELERATION_STRUCTURE_SERIALIZATION_SIZE_KHR = 1000150000,
        VK_QUERY_TYPE_PERFORMANCE_QUERY_INTEL = 1000210000,
        VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_NV = VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_KHR,
        VK_QUERY_TYPE_MAX_ENUM = 0x7FFFFFFF
    } VkQueryType;

- `VK_QUERY_TYPE_OCCLUSION` specifies an occlusion query.

- `VK_QUERY_TYPE_PIPELINE_STATISTICS` specifies a pipeline statistics query.

- `VK_QUERY_TYPE_TIMESTAMP` specifies a timestamp query.

- `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR` specifies a performance query.

- `VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT` specifies a transform feedback query.

- `VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_KHR` specifies a ray tracing acceleration structure size query.

- `VK_QUERY_TYPE_ACCELERATION_STRUCTURE_SERIALIZATION_SIZE_KHR` specifies a ray tracing serialization acceleration structure size query

- `VK_QUERY_TYPE_PERFORMANCE_QUERY_INTEL` specifies a Intel performance query.

### 17.2. Query Operation

The operation of queries is controlled by the commands vkCmdBeginQuery, vkCmdEndQuery, vkCmdBeginQueryIndexedEXT, vkCmdEndQueryIndexedEXT, vkCmdResetQueryPool, vkCmdCopyQueryPoolResults, and vkCmdWriteTimestamp.

In order for a `VkCommandBuffer` to record query management commands, the queue family for which its `VkCommandPool` was created must support the appropriate type of operations (graphics, compute) suitable for the query type of a given query pool.

Each query in a query pool has a status that is either unavailable or available, and also has state to store the numerical results of a query operation of the type requested when the query pool was created. Resetting a query via vkCmdResetQueryPool or vkResetQueryPool sets the status to unavailable and makes the numerical results undefined. Performing a query operation with vkCmdBeginQuery and vkCmdEndQuery changes the status to available when the query finishes, and updates the numerical results. Both the availability status and numerical results are retrieved by calling either vkGetQueryPoolResults or vkCmdCopyQueryPoolResults.

Query commands, for the same query and submitted to the same queue, execute in their entirety in submission order, relative to each other. In effect there is an implicit execution dependency from each such query command to all query command previously submitted to the same queue. There is one significant exception to this; if the `flags` parameter of vkCmdCopyQueryPoolResults does not include `VK_QUERY_RESULT_WAIT_BIT`, execution of vkCmdCopyQueryPoolResults may happen-before the results of vkCmdEndQuery are available.

After query pool creation, each query must be reset before it is used. Queries must also be reset between uses.

If a logical device includes multiple physical devices, then each command that writes a query must execute on a single physical device, and any call to vkCmdBeginQuery must execute the corresponding vkCmdEndQuery command on the same physical device.

To reset a range of queries in a query pool on a queue, call:

    void vkCmdResetQueryPool(
        VkCommandBuffer                             commandBuffer,
        VkQueryPool                                 queryPool,
        uint32_t                                    firstQuery,
        uint32_t                                    queryCount);

- `commandBuffer` is the command buffer into which this command will be recorded.

- `queryPool` is the handle of the query pool managing the queries being reset.

- `firstQuery` is the initial query index to reset.

- `queryCount` is the number of queries to reset.

When executed on a queue, this command sets the status of query indices [`firstQuery`, `firstQuery` + `queryCount` - 1] to unavailable.

If the `queryType` used to create `queryPool` was `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR`, this command sets the status of query indices [`firstQuery`, `firstQuery` + `queryCount` - 1] to unavailable for each pass of `queryPool`, as indicated by a call to vkGetPhysicalDeviceQueueFamilyPerformanceQueryPassesKHR.

| Note Because `vkCmdResetQueryPool` resets all the passes of the indicated queries, applications must not record a `vkCmdResetQueryPool` command for a `queryPool` created with `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR` in a command buffer that needs to be submitted multiple times as indicated by a call to vkGetPhysicalDeviceQueueFamilyPerformanceQueryPassesKHR. Otherwise applications will never be able to complete the recorded queries.

Valid Usage

- `firstQuery` must be less than the number of queries in `queryPool`

- The sum of `firstQuery` and `queryCount` must be less than or equal to the number of queries in `queryPool`

- All queries used by the command must not be active

- If `queryPool` was created with `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR`, this command must not be recorded in a command buffer that, either directly or through secondary command buffers, also contains begin commands for a query from the set of queries [`firstQuery`, `firstQuery` + `queryCount` - 1]

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `queryPool` must be a valid VkQueryPool handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

- This command must only be called outside of a render pass instance

- Both of `commandBuffer`, and `queryPool` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Graphics Compute |

To reset a range of queries in a query pool on the host, call:

    void vkResetQueryPool(
        VkDevice                                    device,
        VkQueryPool                                 queryPool,
        uint32_t                                    firstQuery,
        uint32_t                                    queryCount);

or the equivalent command

    void vkResetQueryPoolEXT(
        VkDevice                                    device,
        VkQueryPool                                 queryPool,
        uint32_t                                    firstQuery,
        uint32_t                                    queryCount);

- `device` is the logical device that owns the query pool.

- `queryPool` is the handle of the query pool managing the queries being reset.

- `firstQuery` is the initial query index to reset.

- `queryCount` is the number of queries to reset.

This command sets the status of query indices [`firstQuery`, `firstQuery` + `queryCount` - 1] to unavailable.

If `queryPool` is `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR` this command sets the status of query indices [`firstQuery`, `firstQuery` + `queryCount` - 1] to unavailable for each pass.

Valid Usage

- The hostQueryReset feature must be enabled

- `firstQuery` must be less than the number of queries in `queryPool`

- The sum of `firstQuery` and `queryCount` must be less than or equal to the number of queries in `queryPool`

- Submitted commands that refer to the range specified by `firstQuery` and `queryCount` in `queryPool` must have completed execution

- The range of queries specified by `firstQuery` and `queryCount` in `queryPool` must not be in use by calls to vkGetQueryPoolResults or `vkResetQueryPool` in other threads

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `queryPool` must be a valid VkQueryPool handle

- `queryPool` must have been created, allocated, or retrieved from `device`

Once queries are reset and ready for use, query commands can be issued to a command buffer. Occlusion queries and pipeline statistics queries count events - drawn samples and pipeline stage invocations, respectively - resulting from commands that are recorded between a vkCmdBeginQuery command and a vkCmdEndQuery command within a specified command buffer, effectively scoping a set of drawing and/or dispatch commands. Timestamp queries write timestamps to a query pool. Performance queries record performance counters to a query pool.

A query must begin and end in the same command buffer, although if it is a primary command buffer, and the inherited queries feature is enabled, it can execute secondary command buffers during the query operation. For a secondary command buffer to be executed while a query is active, it must set the `occlusionQueryEnable`, `queryFlags`, and/or `pipelineStatistics` members of VkCommandBufferInheritanceInfo to conservative values, as described in the Command Buffer Recording section. A query must either begin and end inside the same subpass of a render pass instance, or must both begin and end outside of a render pass instance (i.e. contain entire render pass instances).

If queries are used while executing a render pass instance that has multiview enabled, the query uses N consecutive query indices in the query pool (starting at `query`) where N is the number of bits set in the view mask in the subpass the query is used in. How the numerical results of the query are distributed among the queries is implementation-dependent. For example, some implementations may write each view’s results to a distinct query, while other implementations may write the total result to the first query and write zero to the other queries. However, the sum of the results in all the queries must accurately reflect the total result of the query summed over all views. Applications can sum the results from all the queries to compute the total result.

Queries used with multiview rendering must not span subpasses, i.e. they must begin and end in the same subpass.

To begin a query, call:

    void vkCmdBeginQuery(
        VkCommandBuffer                             commandBuffer,
        VkQueryPool                                 queryPool,
        uint32_t                                    query,
        VkQueryControlFlags                         flags);

- `commandBuffer` is the command buffer into which this command will be recorded.

- `queryPool` is the query pool that will manage the results of the query.

- `query` is the query index within the query pool that will contain the results.

- `flags` is a bitmask of VkQueryControlFlagBits specifying constraints on the types of queries that can be performed.

If the `queryType` of the pool is `VK_QUERY_TYPE_OCCLUSION` and `flags` contains `VK_QUERY_CONTROL_PRECISE_BIT`, an implementation must return a result that matches the actual number of samples passed. This is described in more detail in Occlusion Queries.

Calling `vkCmdBeginQuery` is equivalent to calling vkCmdBeginQueryIndexedEXT with the `index` parameter set to zero.

After beginning a query, that query is considered active within the command buffer it was called in until that same query is ended. Queries active in a primary command buffer when secondary command buffers are executed are considered active for those secondary command buffers.

Valid Usage

- `queryPool` must have been created with a `queryType` that differs from that of any queries that are active within `commandBuffer`

- All queries used by the command must be unavailable

- The `queryType` used to create `queryPool` must not be `VK_QUERY_TYPE_TIMESTAMP`

- If the precise occlusion queries feature is not enabled, or the `queryType` used to create `queryPool` was not `VK_QUERY_TYPE_OCCLUSION`, `flags` must not contain `VK_QUERY_CONTROL_PRECISE_BIT`

- `query` must be less than the number of queries in `queryPool`

- If the `queryType` used to create `queryPool` was `VK_QUERY_TYPE_OCCLUSION`, the `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- If the `queryType` used to create `queryPool` was `VK_QUERY_TYPE_PIPELINE_STATISTICS` and any of the `pipelineStatistics` indicate graphics operations, the `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- If the `queryType` used to create `queryPool` was `VK_QUERY_TYPE_PIPELINE_STATISTICS` and any of the `pipelineStatistics` indicate compute operations, the `VkCommandPool` that `commandBuffer` was allocated from must support compute operations

- `commandBuffer` must not be a protected command buffer

- If called within a render pass instance, the sum of `query` and the number of bits set in the current subpass’s view mask must be less than or equal to the number of queries in `queryPool`

- If the `queryType` used to create `queryPool` was `VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT` the `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- If the `queryType` used to create `queryPool` was `VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT` then `VkPhysicalDeviceTransformFeedbackPropertiesEXT`::`transformFeedbackQueries` must be supported

- If `queryPool` was created with a `queryType` of `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR`, the profiling lock must have been held before vkBeginCommandBuffer was called on `commandBuffer`

- If `queryPool` was created with a `queryType` of `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR` and one of the counters used to create `queryPool` was `VK_PERFORMANCE_COUNTER_SCOPE_COMMAND_BUFFER_KHR`, the query begin must be the first recorded command in `commandBuffer`

- If `queryPool` was created with a `queryType` of `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR` and one of the counters used to create `queryPool` was `VK_PERFORMANCE_COUNTER_SCOPE_RENDER_PASS_KHR`, the begin command must not be recorded within a render pass instance

- If `queryPool` was created with a `queryType` of `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR` and another query pool with a `queryType` `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR` has been used within `commandBuffer`, its parent primary command buffer or secondary command buffer recorded within the same parent primary command buffer as `commandBuffer`, the `performanceCounterMultipleQueryPools` feature must be enabled

- If `queryPool` was created with a `queryType` of `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR`, this command must not be recorded in a command buffer that, either directly or through secondary command buffers, also contains a `vkCmdResetQueryPool` command affecting the same query.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `queryPool` must be a valid VkQueryPool handle

- `flags` must be a valid combination of VkQueryControlFlagBits values

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

- Both of `commandBuffer`, and `queryPool` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute |

To begin an indexed query, call:

    void vkCmdBeginQueryIndexedEXT(
        VkCommandBuffer                             commandBuffer,
        VkQueryPool                                 queryPool,
        uint32_t                                    query,
        VkQueryControlFlags                         flags,
        uint32_t                                    index);

- `commandBuffer` is the command buffer into which this command will be recorded.

- `queryPool` is the query pool that will manage the results of the query.

- `query` is the query index within the query pool that will contain the results.

- `flags` is a bitmask of VkQueryControlFlagBits specifying constraints on the types of queries that can be performed.

- `index` is the query type specific index. When the query type is `VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT` the index represents the vertex stream.

The `vkCmdBeginQueryIndexedEXT` command operates the same as the vkCmdBeginQuery command, except that it also accepts a query type specific `index` parameter.

Valid Usage

- `queryPool` must have been created with a `queryType` that differs from that of any queries that are active within `commandBuffer`

- All queries used by the command must be unavailable

- The `queryType` used to create `queryPool` must not be `VK_QUERY_TYPE_TIMESTAMP`

- If the precise occlusion queries feature is not enabled, or the `queryType` used to create `queryPool` was not `VK_QUERY_TYPE_OCCLUSION`, `flags` must not contain `VK_QUERY_CONTROL_PRECISE_BIT`

- `query` must be less than the number of queries in `queryPool`

- If the `queryType` used to create `queryPool` was `VK_QUERY_TYPE_OCCLUSION`, the `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- If the `queryType` used to create `queryPool` was `VK_QUERY_TYPE_PIPELINE_STATISTICS` and any of the `pipelineStatistics` indicate graphics operations, the `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- If the `queryType` used to create `queryPool` was `VK_QUERY_TYPE_PIPELINE_STATISTICS` and any of the `pipelineStatistics` indicate compute operations, the `VkCommandPool` that `commandBuffer` was allocated from must support compute operations

- `commandBuffer` must not be a protected command buffer

- If called within a render pass instance, the sum of `query` and the number of bits set in the current subpass’s view mask must be less than or equal to the number of queries in `queryPool`

- If the `queryType` used to create `queryPool` was `VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT` the `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- If the `queryType` used to create `queryPool` was `VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT` the `index` parameter must be less than `VkPhysicalDeviceTransformFeedbackPropertiesEXT`::`maxTransformFeedbackStreams`

- If the `queryType` used to create `queryPool` was not `VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT` the `index` must be zero

- If the `queryType` used to create `queryPool` was `VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT` then `VkPhysicalDeviceTransformFeedbackPropertiesEXT`::`transformFeedbackQueries` must be supported

- If `queryPool` was created with a `queryType` of `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR`, the profiling lock must have been held before vkBeginCommandBuffer was called on `commandBuffer`

- If `queryPool` was created with a `queryType` of `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR` and one of the counters used to create `queryPool` was `VK_PERFORMANCE_COUNTER_SCOPE_COMMAND_BUFFER_KHR`, the query begin must be the first recorded command in `commandBuffer`

- If `queryPool` was created with a `queryType` of `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR` and one of the counters used to create `queryPool` was `VK_PERFORMANCE_COUNTER_SCOPE_RENDER_PASS_KHR`, the begin command must not be recorded within a render pass instance

- If `queryPool` was created with a `queryType` of `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR` and another query pool with a `queryType` `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR` has been used within `commandBuffer`, its parent primary command buffer or secondary command buffer recorded within the same parent primary command buffer as `commandBuffer`, the `performanceCounterMultipleQueryPools` feature must be enabled

- If `queryPool` was created with a `queryType` of `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR`, this command must not be recorded in a command buffer that, either directly or through secondary command buffers, also contains a `vkCmdResetQueryPool` command affecting the same query.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `queryPool` must be a valid VkQueryPool handle

- `flags` must be a valid combination of VkQueryControlFlagBits values

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

- Both of `commandBuffer`, and `queryPool` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute |

Bits which can be set in vkCmdBeginQuery::`flags`, specifying constraints on the types of queries that can be performed, are:

    typedef enum VkQueryControlFlagBits {
        VK_QUERY_CONTROL_PRECISE_BIT = 0x00000001,
        VK_QUERY_CONTROL_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkQueryControlFlagBits;

- `VK_QUERY_CONTROL_PRECISE_BIT` specifies the precision of occlusion queries.

    typedef VkFlags VkQueryControlFlags;

`VkQueryControlFlags` is a bitmask type for setting a mask of zero or more VkQueryControlFlagBits.

To end a query after the set of desired draw or dispatch commands is executed, call:

    void vkCmdEndQuery(
        VkCommandBuffer                             commandBuffer,
        VkQueryPool                                 queryPool,
        uint32_t                                    query);

- `commandBuffer` is the command buffer into which this command will be recorded.

- `queryPool` is the query pool that is managing the results of the query.

- `query` is the query index within the query pool where the result is stored.

Calling `vkCmdEndQuery` is equivalent to calling vkCmdEndQueryIndexedEXT with the `index` parameter set to zero.

As queries operate asynchronously, ending a query does not immediately set the query’s status to available. A query is considered finished when the final results of the query are ready to be retrieved by vkGetQueryPoolResults and vkCmdCopyQueryPoolResults, and this is when the query’s status is set to available.

Once a query is ended the query must finish in finite time, unless the state of the query is changed using other commands, e.g. by issuing a reset of the query.

Valid Usage

- All queries used by the command must be active

- `query` must be less than the number of queries in `queryPool`

- `commandBuffer` must not be a protected command buffer

- If `vkCmdEndQuery` is called within a render pass instance, the sum of `query` and the number of bits set in the current subpass’s view mask must be less than or equal to the number of queries in `queryPool`

- If `queryPool` was created with a `queryType` of `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR` and one or more of the counters used to create `queryPool` was `VK_PERFORMANCE_COUNTER_SCOPE_COMMAND_BUFFER_KHR`, the vkCmdEndQuery must be the last recorded command in `commandBuffer`

- If `queryPool` was created with a `queryType` of `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR` and one or more of the counters used to create `queryPool` was `VK_PERFORMANCE_COUNTER_SCOPE_RENDER_PASS_KHR`, the vkCmdEndQuery must not be recorded within a render pass instance

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `queryPool` must be a valid VkQueryPool handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

- Both of `commandBuffer`, and `queryPool` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute |

To end an indexed query after the set of desired draw or dispatch commands is recorded, call:

    void vkCmdEndQueryIndexedEXT(
        VkCommandBuffer                             commandBuffer,
        VkQueryPool                                 queryPool,
        uint32_t                                    query,
        uint32_t                                    index);

- `commandBuffer` is the command buffer into which this command will be recorded.

- `queryPool` is the query pool that is managing the results of the query.

- `query` is the query index within the query pool where the result is stored.

- `index` is the query type specific index.

The `vkCmdEndQueryIndexedEXT` command operates the same as the vkCmdEndQuery command, except that it also accepts a query type specific `index` parameter.

Valid Usage

- All queries used by the command must be active

- `query` must be less than the number of queries in `queryPool`

- `commandBuffer` must not be a protected command buffer

- If `vkCmdEndQueryIndexedEXT` is called within a render pass instance, the sum of `query` and the number of bits set in the current subpass’s view mask must be less than or equal to the number of queries in `queryPool`

- If the `queryType` used to create `queryPool` was `VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT` the `index` parameter must be less than `VkPhysicalDeviceTransformFeedbackPropertiesEXT`::`maxTransformFeedbackStreams`

- If the `queryType` used to create `queryPool` was not `VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT` the `index` must be zero

- If the `queryType` used to create `queryPool` was `VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT` `index` must equal the `index` used to begin the query

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `queryPool` must be a valid VkQueryPool handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

- Both of `commandBuffer`, and `queryPool` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute |

An application can retrieve results either by requesting they be written into application-provided memory, or by requesting they be copied into a `VkBuffer`. In either case, the layout in memory is defined as follows:

- The first query’s result is written starting at the first byte requested by the command, and each subsequent query’s result begins `stride` bytes later.

- Occlusion queries, pipeline statistics queries, transform feedback queries, and timestamp queries store results in a tightly packed array of unsigned integers, either 32- or 64-bits as requested by the command, storing the numerical results and, if requested, the availability status.

- Performance queries store results in a tightly packed array whose type is determined by the `unit` member of the corresponding VkPerformanceCounterKHR.

- If `VK_QUERY_RESULT_WITH_AVAILABILITY_BIT` is used, the final element of each query’s result is an integer indicating whether the query’s result is available, with any non-zero value indicating that it is available.

- Occlusion queries write one integer value - the number of samples passed. Pipeline statistics queries write one integer value for each bit that is enabled in the `pipelineStatistics` when the pool is created, and the statistics values are written in bit order starting from the least significant bit. Timestamp queries write one integer value. Performance queries write one VkPerformanceCounterResultKHR value for each VkPerformanceCounterKHR in the query. Transform feedback queries write two integers; the first integer is the number of primitives successfully written to the corresponding transform feedback buffer and the second is the number of primitives output to the vertex stream, regardless of whether they were successfully captured or not. In other words, if the transform feedback buffer was sized too small for the number of primitives output by the vertex stream, the first integer represents the number of primitives actually written and the second is the number that would have been written if all the transform feedback buffers associated with that vertex stream were large enough.

- If more than one query is retrieved and `stride` is not at least as large as the size of the array of values corresponding to a single query, the values written to memory are undefined.

To retrieve status and results for a set of queries, call:

    VkResult vkGetQueryPoolResults(
        VkDevice                                    device,
        VkQueryPool                                 queryPool,
        uint32_t                                    firstQuery,
        uint32_t                                    queryCount,
        size_t                                      dataSize,
        void*                                       pData,
        VkDeviceSize                                stride,
        VkQueryResultFlags                          flags);

- `device` is the logical device that owns the query pool.

- `queryPool` is the query pool managing the queries containing the desired results.

- `firstQuery` is the initial query index.

- `queryCount` is the number of queries to read.

- `dataSize` is the size in bytes of the buffer pointed to by `pData`.

- `pData` is a pointer to a user-allocated buffer where the results will be written

- `stride` is the stride in bytes between results for individual queries within `pData`.

- `flags` is a bitmask of VkQueryResultFlagBits specifying how and when results are returned.

The range of queries read is defined by [`firstQuery`, `firstQuery` + `queryCount` - 1]. For pipeline statistics queries, each query index in the pool contains one integer value for each bit that is enabled in VkQueryPoolCreateInfo::`pipelineStatistics` when the pool is created.

If no bits are set in `flags`, and all requested queries are in the available state, results are written as an array of 32-bit unsigned integer values. The behavior when not all queries are available, is described below.

If `VK_QUERY_RESULT_64_BIT` is not set and the result overflows a 32-bit value, the value may either wrap or saturate. Similarly, if `VK_QUERY_RESULT_64_BIT` is set and the result overflows a 64-bit value, the value may either wrap or saturate.

If `VK_QUERY_RESULT_WAIT_BIT` is set, Vulkan will wait for each query to be in the available state before retrieving the numerical results for that query. In this case, `vkGetQueryPoolResults` is guaranteed to succeed and return `VK_SUCCESS` if the queries become available in a finite time (i.e. if they have been issued and not reset). If queries will never finish (e.g. due to being reset but not issued), then `vkGetQueryPoolResults` may not return in finite time.

If `VK_QUERY_RESULT_WAIT_BIT` and `VK_QUERY_RESULT_PARTIAL_BIT` are both not set then no result values are written to `pData` for queries that are in the unavailable state at the time of the call, and `vkGetQueryPoolResults` returns `VK_NOT_READY`. However, availability state is still written to `pData` for those queries if `VK_QUERY_RESULT_WITH_AVAILABILITY_BIT` is set.

| Note Applications must take care to ensure that use of the `VK_QUERY_RESULT_WAIT_BIT` bit has the desired effect. For example, if a query has been used previously and a command buffer records the commands `vkCmdResetQueryPool`, `vkCmdBeginQuery`, and `vkCmdEndQuery` for that query, then the query will remain in the available state until `vkResetQueryPool` is called or the `vkCmdResetQueryPool` command executes on a queue. Applications can use fences or events to ensure that a query has already been reset before checking for its results or availability status. Otherwise, a stale value could be returned from a previous use of the query. The above also applies when `VK_QUERY_RESULT_WAIT_BIT` is used in combination with `VK_QUERY_RESULT_WITH_AVAILABILITY_BIT`. In this case, the returned availability status may reflect the result of a previous use of the query unless `vkResetQueryPool` is called or the `vkCmdResetQueryPool` command has been executed since the last use of the query.

| Note Applications can double-buffer query pool usage, with a pool per frame, and reset queries at the end of the frame in which they are read.

If `VK_QUERY_RESULT_PARTIAL_BIT` is set, `VK_QUERY_RESULT_WAIT_BIT` is not set, and the query’s status is unavailable, an intermediate result value between zero and the final result value is written to `pData` for that query.

If `VK_QUERY_RESULT_WITH_AVAILABILITY_BIT` is set, the final integer value written for each query is non-zero if the query’s status was available or zero if the status was unavailable. When `VK_QUERY_RESULT_WITH_AVAILABILITY_BIT` is used, implementations must guarantee that if they return a non-zero availability value then the numerical results must be valid, assuming the results are not reset by a subsequent command.

| Note Satisfying this guarantee may require careful ordering by the application, e.g. to read the availability status before reading the results.

Valid Usage

- `firstQuery` must be less than the number of queries in `queryPool`

- If `VK_QUERY_RESULT_64_BIT` is not set in `flags`, then `pData` and `stride` must be multiples of `4`

- If `VK_QUERY_RESULT_64_BIT` is not set in `flags` and the `queryType` used to create `queryPool` was not `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR`, then `pData` and `stride` must be multiples of `4`

- If `VK_QUERY_RESULT_64_BIT` is set in `flags` then `pData` and `stride` must be multiples of `8`

- If the `queryType` used to create `queryPool` was `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR`, then `pData` and `stride` must be multiples of the size of VkPerformanceCounterResultKHR

- The sum of `firstQuery` and `queryCount` must be less than or equal to the number of queries in `queryPool`

- `dataSize` must be large enough to contain the result of each query, as described here

- If the `queryType` used to create `queryPool` was `VK_QUERY_TYPE_TIMESTAMP`, `flags` must not contain `VK_QUERY_RESULT_PARTIAL_BIT`

- If the `queryType` used to create `queryPool` was `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR`, `flags` must not contain `VK_QUERY_RESULT_WITH_AVAILABILITY_BIT`, `VK_QUERY_RESULT_PARTIAL_BIT` or `VK_QUERY_RESULT_64_BIT`

- If the `queryType` used to create `queryPool` was `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR`, the `queryPool` must have been recorded once for each pass as retrieved via a call to vkGetPhysicalDeviceQueueFamilyPerformanceQueryPassesKHR

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `queryPool` must be a valid VkQueryPool handle

- `pData` must be a valid pointer to an array of `dataSize` bytes

- `flags` must be a valid combination of VkQueryResultFlagBits values

- `dataSize` must be greater than `0`

- `queryPool` must have been created, allocated, or retrieved from `device`

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_NOT_READY`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_DEVICE_LOST`

Bits which can be set in vkGetQueryPoolResults::`flags` and vkCmdCopyQueryPoolResults::`flags`, specifying how and when results are returned, are:

    typedef enum VkQueryResultFlagBits {
        VK_QUERY_RESULT_64_BIT = 0x00000001,
        VK_QUERY_RESULT_WAIT_BIT = 0x00000002,
        VK_QUERY_RESULT_WITH_AVAILABILITY_BIT = 0x00000004,
        VK_QUERY_RESULT_PARTIAL_BIT = 0x00000008,
        VK_QUERY_RESULT_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkQueryResultFlagBits;

- `VK_QUERY_RESULT_64_BIT` specifies the results will be written as an array of 64-bit unsigned integer values. If this bit is not set, the results will be written as an array of 32-bit unsigned integer values.

- `VK_QUERY_RESULT_WAIT_BIT` specifies that Vulkan will wait for each query’s status to become available before retrieving its results.

- `VK_QUERY_RESULT_WITH_AVAILABILITY_BIT` specifies that the availability status accompanies the results.

- `VK_QUERY_RESULT_PARTIAL_BIT` specifies that returning partial results is acceptable.

    typedef VkFlags VkQueryResultFlags;

`VkQueryResultFlags` is a bitmask type for setting a mask of zero or more VkQueryResultFlagBits.

To copy query statuses and numerical results directly to buffer memory, call:

    void vkCmdCopyQueryPoolResults(
        VkCommandBuffer                             commandBuffer,
        VkQueryPool                                 queryPool,
        uint32_t                                    firstQuery,
        uint32_t                                    queryCount,
        VkBuffer                                    dstBuffer,
        VkDeviceSize                                dstOffset,
        VkDeviceSize                                stride,
        VkQueryResultFlags                          flags);

- `commandBuffer` is the command buffer into which this command will be recorded.

- `queryPool` is the query pool managing the queries containing the desired results.

- `firstQuery` is the initial query index.

- `queryCount` is the number of queries. `firstQuery` and `queryCount` together define a range of queries.

- `dstBuffer` is a VkBuffer object that will receive the results of the copy command.

- `dstOffset` is an offset into `dstBuffer`.

- `stride` is the stride in bytes between results for individual queries within `dstBuffer`. The required size of the backing memory for `dstBuffer` is determined as described above for vkGetQueryPoolResults.

- `flags` is a bitmask of VkQueryResultFlagBits specifying how and when results are returned.

`vkCmdCopyQueryPoolResults` is guaranteed to see the effect of previous uses of `vkCmdResetQueryPool` in the same queue, without any additional synchronization. Thus, the results will always reflect the most recent use of the query.

`flags` has the same possible values described above for the `flags` parameter of vkGetQueryPoolResults, but the different style of execution causes some subtle behavioral differences. Because `vkCmdCopyQueryPoolResults` executes in order with respect to other query commands, there is less ambiguity about which use of a query is being requested.

Results for all requested occlusion queries, pipeline statistics queries, transform feedback queries, and timestamp queries are written as 64-bit unsigned integer values if `VK_QUERY_RESULT_64_BIT` is set or 32-bit unsigned integer values otherwise. Performance queries store results in a tightly packed array whose type is determined by the `unit` member of the corresponding VkPerformanceCounterKHR.

If neither of `VK_QUERY_RESULT_WAIT_BIT` and `VK_QUERY_RESULT_WITH_AVAILABILITY_BIT` are set, results are only written out for queries in the available state.

If `VK_QUERY_RESULT_WAIT_BIT` is set, the implementation will wait for each query’s status to be in the available state before retrieving the numerical results for that query. This is guaranteed to reflect the most recent use of the query on the same queue, assuming that the query is not being simultaneously used by other queues. If the query does not become available in a finite amount of time (e.g. due to not issuing a query since the last reset), a `VK_ERROR_DEVICE_LOST` error may occur.

Similarly, if `VK_QUERY_RESULT_WITH_AVAILABILITY_BIT` is set and `VK_QUERY_RESULT_WAIT_BIT` is not set, the availability is guaranteed to reflect the most recent use of the query on the same queue, assuming that the query is not being simultaneously used by other queues. As with `vkGetQueryPoolResults`, implementations must guarantee that if they return a non-zero availability value, then the numerical results are valid.

If `VK_QUERY_RESULT_PARTIAL_BIT` is set, `VK_QUERY_RESULT_WAIT_BIT` is not set, and the query’s status is unavailable, an intermediate result value between zero and the final result value is written for that query.

`VK_QUERY_RESULT_PARTIAL_BIT` must not be used if the pool’s `queryType` is `VK_QUERY_TYPE_TIMESTAMP`.

`vkCmdCopyQueryPoolResults` is considered to be a transfer operation, and its writes to buffer memory must be synchronized using `VK_PIPELINE_STAGE_TRANSFER_BIT` and `VK_ACCESS_TRANSFER_WRITE_BIT` before using the results.

Valid Usage

- `dstOffset` must be less than the size of `dstBuffer`

- `firstQuery` must be less than the number of queries in `queryPool`

- The sum of `firstQuery` and `queryCount` must be less than or equal to the number of queries in `queryPool`

- If `VK_QUERY_RESULT_64_BIT` is not set in `flags` then `dstOffset` and `stride` must be multiples of `4`

- If `VK_QUERY_RESULT_64_BIT` is set in `flags` then `dstOffset` and `stride` must be multiples of `8`

- `dstBuffer` must have enough storage, from `dstOffset`, to contain the result of each query, as described here

- `dstBuffer` must have been created with `VK_BUFFER_USAGE_TRANSFER_DST_BIT` usage flag

- If `dstBuffer` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- If the `queryType` used to create `queryPool` was `VK_QUERY_TYPE_TIMESTAMP`, `flags` must not contain `VK_QUERY_RESULT_PARTIAL_BIT`

- If the `queryType` used to create `queryPool` was `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR`, VkPhysicalDevicePerformanceQueryPropertiesKHR::`allowCommandBufferQueryCopies` must be `VK_TRUE`

- If the `queryType` used to create `queryPool` was `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR`, `flags` must not contain `VK_QUERY_RESULT_WITH_AVAILABILITY_BIT`, `VK_QUERY_RESULT_PARTIAL_BIT` or `VK_QUERY_RESULT_64_BIT`

- If the `queryType` used to create `queryPool` was `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR`, the `queryPool` must have been submitted once for each pass as retrieved via a call to vkGetPhysicalDeviceQueueFamilyPerformanceQueryPassesKHR

- vkCmdCopyQueryPoolResults must not be called if the `queryType` used to create `queryPool` was `VK_QUERY_TYPE_PERFORMANCE_QUERY_INTEL`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `queryPool` must be a valid VkQueryPool handle

- `dstBuffer` must be a valid VkBuffer handle

- `flags` must be a valid combination of VkQueryResultFlagBits values

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

- This command must only be called outside of a render pass instance

- Each of `commandBuffer`, `dstBuffer`, and `queryPool` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Graphics Compute | Transfer

Rendering operations such as clears, MSAA resolves, attachment load/store operations, and blits may count towards the results of queries. This behavior is implementation-dependent and may vary depending on the path used within an implementation. For example, some implementations have several types of clears, some of which may include vertices and some not.

### 17.3. Occlusion Queries

Occlusion queries track the number of samples that pass the per-fragment tests for a set of drawing commands. As such, occlusion queries are only available on queue families supporting graphics operations. The application can then use these results to inform future rendering decisions. An occlusion query is begun and ended by calling `vkCmdBeginQuery` and `vkCmdEndQuery`, respectively. When an occlusion query begins, the count of passing samples always starts at zero. For each drawing command, the count is incremented as described in Sample Counting. If `flags` does not contain `VK_QUERY_CONTROL_PRECISE_BIT` an implementation may generate any non-zero result value for the query if the count of passing samples is non-zero.

| Note Not setting `VK_QUERY_CONTROL_PRECISE_BIT` mode may be more efficient on some implementations, and should be used where it is sufficient to know a boolean result on whether any samples passed the per-fragment tests. In this case, some implementations may only return zero or one, indifferent to the actual number of samples passing the per-fragment tests.

When an occlusion query finishes, the result for that query is marked as available. The application can then either copy the result to a buffer (via `vkCmdCopyQueryPoolResults`) or request it be put into host memory (via `vkGetQueryPoolResults`).

| Note If occluding geometry is not drawn first, samples can pass the depth test, but still not be visible in a final image.

### 17.4. Pipeline Statistics Queries

Pipeline statistics queries allow the application to sample a specified set of `VkPipeline` counters. These counters are accumulated by Vulkan for a set of either draw or dispatch commands while a pipeline statistics query is active. As such, pipeline statistics queries are available on queue families supporting either graphics or compute operations. The availability of pipeline statistics queries is indicated by the `pipelineStatisticsQuery` member of the `VkPhysicalDeviceFeatures` object (see `vkGetPhysicalDeviceFeatures` and `vkCreateDevice` for detecting and requesting this query type on a `VkDevice`).

A pipeline statistics query is begun and ended by calling `vkCmdBeginQuery` and `vkCmdEndQuery`, respectively. When a pipeline statistics query begins, all statistics counters are set to zero. While the query is active, the pipeline type determines which set of statistics are available, but these must be configured on the query pool when it is created. If a statistic counter is issued on a command buffer that does not support the corresponding operation, the value of that counter is undefined after the query has finished. At least one statistic counter relevant to the operations supported on the recording command buffer must be enabled.

Bits which can be set to individually enable pipeline statistics counters for query pools with VkQueryPoolCreateInfo::`pipelineStatistics`, and for secondary command buffers with VkCommandBufferInheritanceInfo::`pipelineStatistics`, are:

    typedef enum VkQueryPipelineStatisticFlagBits {
        VK_QUERY_PIPELINE_STATISTIC_INPUT_ASSEMBLY_VERTICES_BIT = 0x00000001,
        VK_QUERY_PIPELINE_STATISTIC_INPUT_ASSEMBLY_PRIMITIVES_BIT = 0x00000002,
        VK_QUERY_PIPELINE_STATISTIC_VERTEX_SHADER_INVOCATIONS_BIT = 0x00000004,
        VK_QUERY_PIPELINE_STATISTIC_GEOMETRY_SHADER_INVOCATIONS_BIT = 0x00000008,
        VK_QUERY_PIPELINE_STATISTIC_GEOMETRY_SHADER_PRIMITIVES_BIT = 0x00000010,
        VK_QUERY_PIPELINE_STATISTIC_CLIPPING_INVOCATIONS_BIT = 0x00000020,
        VK_QUERY_PIPELINE_STATISTIC_CLIPPING_PRIMITIVES_BIT = 0x00000040,
        VK_QUERY_PIPELINE_STATISTIC_FRAGMENT_SHADER_INVOCATIONS_BIT = 0x00000080,
        VK_QUERY_PIPELINE_STATISTIC_TESSELLATION_CONTROL_SHADER_PATCHES_BIT = 0x00000100,
        VK_QUERY_PIPELINE_STATISTIC_TESSELLATION_EVALUATION_SHADER_INVOCATIONS_BIT = 0x00000200,
        VK_QUERY_PIPELINE_STATISTIC_COMPUTE_SHADER_INVOCATIONS_BIT = 0x00000400,
        VK_QUERY_PIPELINE_STATISTIC_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkQueryPipelineStatisticFlagBits;

- `VK_QUERY_PIPELINE_STATISTIC_INPUT_ASSEMBLY_VERTICES_BIT` specifies that queries managed by the pool will count the number of vertices processed by the input assembly stage. Vertices corresponding to incomplete primitives may contribute to the count.

- `VK_QUERY_PIPELINE_STATISTIC_INPUT_ASSEMBLY_PRIMITIVES_BIT` specifies that queries managed by the pool will count the number of primitives processed by the input assembly stage. If primitive restart is enabled, restarting the primitive topology has no effect on the count. Incomplete primitives may be counted.

- `VK_QUERY_PIPELINE_STATISTIC_VERTEX_SHADER_INVOCATIONS_BIT` specifies that queries managed by the pool will count the number of vertex shader invocations. This counter’s value is incremented each time a vertex shader is invoked.

- `VK_QUERY_PIPELINE_STATISTIC_GEOMETRY_SHADER_INVOCATIONS_BIT` specifies that queries managed by the pool will count the number of geometry shader invocations. This counter’s value is incremented each time a geometry shader is invoked. In the case of instanced geometry shaders, the geometry shader invocations count is incremented for each separate instanced invocation.

- `VK_QUERY_PIPELINE_STATISTIC_GEOMETRY_SHADER_PRIMITIVES_BIT` specifies that queries managed by the pool will count the number of primitives generated by geometry shader invocations. The counter’s value is incremented each time the geometry shader emits a primitive. Restarting primitive topology using the SPIR-V instructions `OpEndPrimitive` or `OpEndStreamPrimitive` has no effect on the geometry shader output primitives count.

- `VK_QUERY_PIPELINE_STATISTIC_CLIPPING_INVOCATIONS_BIT` specifies that queries managed by the pool will count the number of primitives processed by the Primitive Clipping stage of the pipeline. The counter’s value is incremented each time a primitive reaches the primitive clipping stage.

- `VK_QUERY_PIPELINE_STATISTIC_CLIPPING_PRIMITIVES_BIT` specifies that queries managed by the pool will count the number of primitives output by the Primitive Clipping stage of the pipeline. The counter’s value is incremented each time a primitive passes the primitive clipping stage. The actual number of primitives output by the primitive clipping stage for a particular input primitive is implementation-dependent but must satisfy the following conditions:

  - If at least one vertex of the input primitive lies inside the clipping volume, the counter is incremented by one or more.

  - Otherwise, the counter is incremented by zero or more.

- `VK_QUERY_PIPELINE_STATISTIC_FRAGMENT_SHADER_INVOCATIONS_BIT` specifies that queries managed by the pool will count the number of fragment shader invocations. The counter’s value is incremented each time the fragment shader is invoked.

- `VK_QUERY_PIPELINE_STATISTIC_TESSELLATION_CONTROL_SHADER_PATCHES_BIT` specifies that queries managed by the pool will count the number of patches processed by the tessellation control shader. The counter’s value is incremented once for each patch for which a tessellation control shader is invoked.

- `VK_QUERY_PIPELINE_STATISTIC_TESSELLATION_EVALUATION_SHADER_INVOCATIONS_BIT` specifies that queries managed by the pool will count the number of invocations of the tessellation evaluation shader. The counter’s value is incremented each time the tessellation evaluation shader is invoked.

- `VK_QUERY_PIPELINE_STATISTIC_COMPUTE_SHADER_INVOCATIONS_BIT` specifies that queries managed by the pool will count the number of compute shader invocations. The counter’s value is incremented every time the compute shader is invoked. Implementations may skip the execution of certain compute shader invocations or execute additional compute shader invocations for implementation-dependent reasons as long as the results of rendering otherwise remain unchanged.

These values are intended to measure relative statistics on one implementation. Various device architectures will count these values differently. Any or all counters may be affected by the issues described in Query Operation.

| Note For example, tile-based rendering devices may need to replay the scene multiple times, affecting some of the counts.

If a pipeline has `rasterizerDiscardEnable` enabled, implementations may discard primitives after the final vertex processing stage. As a result, if `rasterizerDiscardEnable` is enabled, the clipping input and output primitives counters may not be incremented.

When a pipeline statistics query finishes, the result for that query is marked as available. The application can copy the result to a buffer (via `vkCmdCopyQueryPoolResults`), or request it be put into host memory (via `vkGetQueryPoolResults`).

    typedef VkFlags VkQueryPipelineStatisticFlags;

`VkQueryPipelineStatisticFlags` is a bitmask type for setting a mask of zero or more VkQueryPipelineStatisticFlagBits.

### 17.5. Timestamp Queries

Timestamps provide applications with a mechanism for timing the execution of commands. A timestamp is an integer value generated by the `VkPhysicalDevice`. Unlike other queries, timestamps do not operate over a range, and so do not use vkCmdBeginQuery or vkCmdEndQuery. The mechanism is built around a set of commands that allow the application to tell the `VkPhysicalDevice` to write timestamp values to a query pool and then either read timestamp values on the host (using vkGetQueryPoolResults) or copy timestamp values to a `VkBuffer` (using vkCmdCopyQueryPoolResults). The application can then compute differences between timestamps to determine execution time.

The number of valid bits in a timestamp value is determined by the `VkQueueFamilyProperties`::`timestampValidBits` property of the queue on which the timestamp is written. Timestamps are supported on any queue which reports a non-zero value for `timestampValidBits` via vkGetPhysicalDeviceQueueFamilyProperties. If the `timestampComputeAndGraphics` limit is `VK_TRUE`, timestamps are supported by every queue family that supports either graphics or compute operations (see VkQueueFamilyProperties).

The number of nanoseconds it takes for a timestamp value to be incremented by 1 can be obtained from `VkPhysicalDeviceLimits`::`timestampPeriod` after a call to `vkGetPhysicalDeviceProperties`.

To request a timestamp, call:

    void vkCmdWriteTimestamp(
        VkCommandBuffer                             commandBuffer,
        VkPipelineStageFlagBits                     pipelineStage,
        VkQueryPool                                 queryPool,
        uint32_t                                    query);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `pipelineStage` is one of the VkPipelineStageFlagBits, specifying a stage of the pipeline.

- `queryPool` is the query pool that will manage the timestamp.

- `query` is the query within the query pool that will contain the timestamp.

`vkCmdWriteTimestamp` latches the value of the timer when all previous commands have completed executing as far as the specified pipeline stage, and writes the timestamp value to memory. When the timestamp value is written, the availability status of the query is set to available.

| Note If an implementation is unable to detect completion and latch the timer at any specific stage of the pipeline, it may instead do so at any logically later stage.

vkCmdCopyQueryPoolResults can then be called to copy the timestamp value from the query pool into buffer memory, with ordering and synchronization behavior equivalent to how other queries operate. Timestamp values can also be retrieved from the query pool using vkGetQueryPoolResults. As with other queries, the query must be reset using vkCmdResetQueryPool or vkResetQueryPool before requesting the timestamp value be written to it.

While `vkCmdWriteTimestamp` can be called inside or outside of a render pass instance, vkCmdCopyQueryPoolResults must only be called outside of a render pass instance.

Timestamps may only be meaningfully compared if they are written by commands submitted to the same queue.

| Note An example of such a comparison is determining the execution time of a sequence of commands.

If `vkCmdWriteTimestamp` is called while executing a render pass instance that has multiview enabled, the timestamp uses N consecutive query indices in the query pool (starting at `query`) where N is the number of bits set in the view mask of the subpass the command is executed in. The resulting query values are determined by an implementation-dependent choice of one of the following behaviors:

- The first query is a timestamp value and (if more than one bit is set in the view mask) zero is written to the remaining queries. If two timestamps are written in the same subpass, the sum of the execution time of all views between those commands is the difference between the first query written by each command.

- All N queries are timestamp values. If two timestamps are written in the same subpass, the sum of the execution time of all views between those commands is the sum of the difference between corresponding queries written by each command. The difference between corresponding queries may be the execution time of a single view.

In either case, the application can sum the differences between all N queries to determine the total execution time.

Valid Usage

- `queryPool` must have been created with a `queryType` of `VK_QUERY_TYPE_TIMESTAMP`

- The query identified by `queryPool` and `query` must be unavailable

- The command pool’s queue family must support a non-zero `timestampValidBits`

- All queries used by the command must be unavailable

- If `vkCmdWriteTimestamp` is called within a render pass instance, the sum of `query` and the number of bits set in the current subpass’s view mask must be less than or equal to the number of queries in `queryPool`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pipelineStage` must be a valid VkPipelineStageFlagBits value

- `queryPool` must be a valid VkQueryPool handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support transfer, graphics, or compute operations

- Both of `commandBuffer`, and `queryPool` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Transfer Graphics Compute | Transfer

### 17.6. Performance Queries

Performance queries provide applications with a mechanism for getting performance counter information about the execution of command buffers, render passes, and commands.

Each queue family advertises the performance counters that can be queried on a queue of that family via a call to vkEnumeratePhysicalDeviceQueueFamilyPerformanceQueryCountersKHR. Implementations may limit access to performance counters based on platform requirements or only to specialized drivers for development purposes.

| Note This may include no performance counters being enumerated, or a reduced set. Please refer to platform-specific documentation for guidance on any such restrictions.

Performance queries use the existing vkCmdBeginQuery and vkCmdEndQuery to control what command buffers, render passes, or commands to get performance information for.

Implementations may require multiple passes where the command buffer, render passes, or commands being recorded are the same and are executed on the same queue to record performance counter data. This is achieved by submitting the same batch and providing a VkPerformanceQuerySubmitInfoKHR structure containing a counter pass index. The number of passes required for a given performance query pool can be queried via a call to vkGetPhysicalDeviceQueueFamilyPerformanceQueryPassesKHR.

| Note Command buffers created with `VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT` must not be re-submitted. Changing command buffer usage bits may affect performance. To avoid this, the application should re-record any command buffers with the `VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT` when multiple counter passes are required.

Performance counter results from a performance query pool can be obtained with the command vkGetQueryPoolResults.

Performance query results are returned in an array of `VkPerformanceCounterResultKHR` unions containing the data associated with each counter in the query, stored in the same order as the counters supplied in `pCounterIndices` when creating the performance query. The VkPerformanceCounterKHR::`unit` enumeration specifies how to parse the counter data.

    typedef union VkPerformanceCounterResultKHR {
        int32_t     int32;
        int64_t     int64;
        uint32_t    uint32;
        uint64_t    uint64;
        float       float32;
        double      float64;
    } VkPerformanceCounterResultKHR;

#### 17.6.1. Profiling Lock

To record and submit a command buffer that contains a performance query pool the profiling lock must be held. The profiling lock must be acquired prior to any call to vkBeginCommandBuffer that will be using a performance query pool. The profiling lock must be held while any command buffer that contains a performance query pool is in the recording, executable, or pending state. To acquire the profiling lock, call:

    VkResult vkAcquireProfilingLockKHR(
        VkDevice                                    device,
        const VkAcquireProfilingLockInfoKHR*        pInfo);

- `device` is the logical device to profile.

- `pInfo` is a pointer to a `VkAcquireProfilingLockInfoKHR` structure which contains information about how the profiling is to be acquired.

Implementations may allow multiple actors to hold the profiling lock concurrently.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pInfo` must be a valid pointer to a valid VkAcquireProfilingLockInfoKHR structure

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_TIMEOUT`

The `VkAcquireProfilingLockInfoKHR` structure is defined as:

    typedef struct VkAcquireProfilingLockInfoKHR {
        VkStructureType                   sType;
        const void*                       pNext;
        VkAcquireProfilingLockFlagsKHR    flags;
        uint64_t                          timeout;
    } VkAcquireProfilingLockInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `timeout` indicates how long the function waits, in nanoseconds, if the profiling lock is not available.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_ACQUIRE_PROFILING_LOCK_INFO_KHR`

- `pNext` must be `NULL`

- `flags` must be `0`

If `timeout` is 0, `vkAcquireProfilingLockKHR` will not block while attempting to acquire the profling lock. If `timeout` is `UINT64_MAX`, the function will not return until the profiling lock was acquired.

    typedef enum VkAcquireProfilingLockFlagBitsKHR {
        VK_ACQUIRE_PROFILING_LOCK_FLAG_BITS_MAX_ENUM_KHR = 0x7FFFFFFF
    } VkAcquireProfilingLockFlagBitsKHR;

    typedef VkFlags VkAcquireProfilingLockFlagsKHR;

VkAcquireProfilingLockFlagsKHR is a bitmask type for setting a mask, but is currently reserved for future use.

To release the profiling lock, call:

    void vkReleaseProfilingLockKHR(
        VkDevice                                    device);

- `device` is the logical device to cease profiling on.

Valid Usage

- The profiling lock of `device` must have been held via a previous successful call to vkAcquireProfilingLockKHR

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

### 17.7. Transform Feedback Queries

Transform feedback queries track the number of primitives attempted to be written and actually written, by the vertex stream being captured, to a transform feedback buffer. This query is updated during draw commands while transform feedback is active. The number of primitives actually written will be less than the number attempted to be written if the bound transform feedback buffer size was too small for the number of primitives actually drawn. Primitives are not written beyond the bound range of the transform feedback buffer. A transform feedback query is begun and ended by calling `vkCmdBeginQuery` and `vkCmdEndQuery`, respectively to query for vertex stream zero. `vkCmdBeginQueryIndexedEXT` and `vkCmdEndQueryIndexedEXT` can be used to begin and end transform feedback queries for any supported vertex stream. When a transform feedback query begins, the count of primitives written and primitives needed starts from zero. For each drawing command, the count is incremented as vertex attribute outputs are captured to the transform feedback buffers while transform feedback is active.

When a transform feedback query finishes, the result for that query is marked as available. The application can then either copy the result to a buffer (via `vkCmdCopyQueryPoolResults`) or request it be put into host memory (via `vkGetQueryPoolResults`).

### 17.8. Intel performance queries

Intel performance queries allow an application to capture performance data for a set of commands. Performance queries are used in a similar way than other types of queries. A main difference with existing queries is that the resulting data should be handed over to a library capabable to produce human readable results rather than being read directly by an application.

Prior to creating a performance query pool, initialize the device for performance queries with the call:

    VkResult vkInitializePerformanceApiINTEL(
        VkDevice                                    device,
        const VkInitializePerformanceApiInfoINTEL*  pInitializeInfo);

- `device` is the logical device used for the queries.

- `pInitializeInfo` is a pointer to a VkInitializePerformanceApiInfoINTEL structure specifying initialization parameters.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pInitializeInfo` must be a valid pointer to a valid VkInitializePerformanceApiInfoINTEL structure

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_TOO_MANY_OBJECTS`

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

The `VkInitializePerformanceApiInfoINTEL` structure is defined as :

    typedef struct VkInitializePerformanceApiInfoINTEL {
        VkStructureType    sType;
        const void*        pNext;
        void*              pUserData;
    } VkInitializePerformanceApiInfoINTEL;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `pUserData` is a pointer for application data.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_INITIALIZE_PERFORMANCE_API_INFO_INTEL`

- `pNext` must be `NULL`

Once performance query operations have completed, uninitalize the device for performance queries with the call:

    void vkUninitializePerformanceApiINTEL(
        VkDevice                                    device);

- `device` is the logical device used for the queries.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

Some performance query features of a device can be discovered with the call:

    VkResult vkGetPerformanceParameterINTEL(
        VkDevice                                    device,
        VkPerformanceParameterTypeINTEL             parameter,
        VkPerformanceValueINTEL*                    pValue);

- `device` is the logical device to query.

- `parameter` is the parameter to query.

- `pValue` is a pointer to a VkPerformanceValueINTEL structure in which the type and value of the parameter are returned.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `parameter` must be a valid VkPerformanceParameterTypeINTEL value

- `pValue` must be a valid pointer to a VkPerformanceValueINTEL structure

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_TOO_MANY_OBJECTS`

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

Possible values of vkGetPerformanceParameterINTEL::`parameter`, specifying a performance query feature, are:

    typedef enum VkPerformanceParameterTypeINTEL {
        VK_PERFORMANCE_PARAMETER_TYPE_HW_COUNTERS_SUPPORTED_INTEL = 0,
        VK_PERFORMANCE_PARAMETER_TYPE_STREAM_MARKER_VALID_BITS_INTEL = 1,
        VK_PERFORMANCE_PARAMETER_TYPE_MAX_ENUM_INTEL = 0x7FFFFFFF
    } VkPerformanceParameterTypeINTEL;

- `VK_PERFORMANCE_PARAMETER_TYPE_HW_COUNTERS_SUPPORTED_INTEL` has a boolean result which tells whether hardware counters can be captured.

- `VK_PERFORMANCE_PARAMETER_TYPE_STREAM_MARKER_VALID_BITS_INTEL` has a 32 bits integer result which tells how many bits can be written into the `VkPerformanceValueINTEL` value.

The `VkPerformanceValueINTEL` structure is defined as:

    typedef struct VkPerformanceValueINTEL {
        VkPerformanceValueTypeINTEL    type;
        VkPerformanceValueDataINTEL    data;
    } VkPerformanceValueINTEL;

- `type` is a VkPerformanceValueTypeINTEL value specifying the type of the returned data.

- `data` is a VkPerformanceValueDataINTEL union specifying the value of the returned data.

Valid Usage (Implicit)

- `type` must be a valid VkPerformanceValueTypeINTEL value

- `data` must be a valid VkPerformanceValueDataINTEL union

Possible values of VkPerformanceValueINTEL::`type`, specifying the type of the data returned in VkPerformanceValueINTEL::`data`, are:

- `VK_PERFORMANCE_VALUE_TYPE_UINT32_INTEL` specifies that unsigned 32-bit integer data is returned in `data.value32`.

- `VK_PERFORMANCE_VALUE_TYPE_UINT64_INTEL` specifies that unsigned 64-bit integer data is returned in `data.value64`.

- `VK_PERFORMANCE_VALUE_TYPE_FLOAT_INTEL` specifies that floating-point data is returned in `data.valueFloat`.

- `VK_PERFORMANCE_VALUE_TYPE_BOOL_INTEL` specifies that `Bool32` data is returned in `data.valueBool`.

- `VK_PERFORMANCE_VALUE_TYPE_STRING_INTEL` specifies that a pointer to a null-terminated UTF-8 string is returned in `data.valueString`. The pointer is valid for the lifetime of the `device` parameter passed to vkGetPerformanceParameterINTEL.

    typedef enum VkPerformanceValueTypeINTEL {
        VK_PERFORMANCE_VALUE_TYPE_UINT32_INTEL = 0,
        VK_PERFORMANCE_VALUE_TYPE_UINT64_INTEL = 1,
        VK_PERFORMANCE_VALUE_TYPE_FLOAT_INTEL = 2,
        VK_PERFORMANCE_VALUE_TYPE_BOOL_INTEL = 3,
        VK_PERFORMANCE_VALUE_TYPE_STRING_INTEL = 4,
        VK_PERFORMANCE_VALUE_TYPE_MAX_ENUM_INTEL = 0x7FFFFFFF
    } VkPerformanceValueTypeINTEL;

The `VkPerformanceValueDataINTEL` union is defined as:

    typedef union VkPerformanceValueDataINTEL {
        uint32_t       value32;
        uint64_t       value64;
        float          valueFloat;
        VkBool32       valueBool;
        const char*    valueString;
    } VkPerformanceValueDataINTEL;

- `data.value32` represents 32-bit integer data.

- `data.value64` represents 64-bit integer data.

- `data.valueFloat` represents floating-point data.

- `data.valueBool` represents `Bool32` data.

- `data.valueString` represents a pointer to a null-terminated UTF-8 string.

The correct member of the union is determined by the associated VkPerformanceValueTypeINTEL value.

Valid Usage (Implicit)

- `valueString` must be a valid pointer to a valid

The `VkQueryPoolPerformanceQueryCreateInfoINTEL` structure is defined as:

    typedef struct VkQueryPoolPerformanceQueryCreateInfoINTEL {
        VkStructureType                 sType;
        const void*                     pNext;
        VkQueryPoolSamplingModeINTEL    performanceCountersSampling;
    } VkQueryPoolPerformanceQueryCreateInfoINTEL;

To create a pool for Intel performance queries, set VkQueryPoolCreateInfo::`queryType` to `VK_QUERY_TYPE_PERFORMANCE_QUERY_INTEL` and add a `VkQueryPoolPerformanceQueryCreateInfoINTEL` structure to the `pNext` chain of the VkQueryPoolCreateInfo structure.

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `performanceCountersSampling` describe how performance queries should be captured.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_QUERY_POOL_CREATE_INFO_INTEL`

- `performanceCountersSampling` must be a valid VkQueryPoolSamplingModeINTEL value

Possible values of VkQueryPoolPerformanceQueryCreateInfoINTEL::`performanceCountersSampling` are:

    typedef enum VkQueryPoolSamplingModeINTEL {
        VK_QUERY_POOL_SAMPLING_MODE_MANUAL_INTEL = 0,
        VK_QUERY_POOL_SAMPLING_MODE_MAX_ENUM_INTEL = 0x7FFFFFFF
    } VkQueryPoolSamplingModeINTEL;

- `VK_QUERY_POOL_SAMPLING_MODE_MANUAL_INTEL` is the default mode in which the application calls vkCmdBeginQuery and vkCmdEndQuery to record performance data.

To help associate query results with a particular point at which an application emitted commands, markers can be set into the command buffers with the call:

    VkResult vkCmdSetPerformanceMarkerINTEL(
        VkCommandBuffer                             commandBuffer,
        const VkPerformanceMarkerInfoINTEL*         pMarkerInfo);

The last marker set onto a command buffer before the end of a query will be part of the query result.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pMarkerInfo` must be a valid pointer to a valid VkPerformanceMarkerInfoINTEL structure

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, compute, or transfer operations

Host Synchronization

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute Transfer |

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_TOO_MANY_OBJECTS`

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

The `VkPerformanceMarkerInfoINTEL` structure is defined as:

    typedef struct VkPerformanceMarkerInfoINTEL {
        VkStructureType    sType;
        const void*        pNext;
        uint64_t           marker;
    } VkPerformanceMarkerInfoINTEL;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `marker` is the marker value that will be recorded into the opaque query results.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PERFORMANCE_MARKER_INFO_INTEL`

- `pNext` must be `NULL`

When monitoring the behavior of an application wihtin the dataset generated by the entire set of applications running on the system, it is useful to identify draw calls within a potentially huge amount of performance data. To do so, application can generate stream markers that will be used to trace back a particular draw call with a particular performance data item.

    VkResult vkCmdSetPerformanceStreamMarkerINTEL(
        VkCommandBuffer                             commandBuffer,
        const VkPerformanceStreamMarkerInfoINTEL*   pMarkerInfo);

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pMarkerInfo` must be a valid pointer to a valid VkPerformanceStreamMarkerInfoINTEL structure

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, compute, or transfer operations

Host Synchronization

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute Transfer |

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_TOO_MANY_OBJECTS`

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

The `VkPerformanceStreamMarkerInfoINTEL` structure is defined as:

    typedef struct VkPerformanceStreamMarkerInfoINTEL {
        VkStructureType    sType;
        const void*        pNext;
        uint32_t           marker;
    } VkPerformanceStreamMarkerInfoINTEL;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `marker` is the marker value that will be recorded into the reports consumed by an external application.

Valid Usage

- The value written by the application into `marker` must only used the valid bits as reported by vkGetPerformanceParameterINTEL with the `VK_PERFORMANCE_PARAMETER_TYPE_STREAM_MARKER_VALID_BITS_INTEL`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PERFORMANCE_STREAM_MARKER_INFO_INTEL`

- `pNext` must be `NULL`

Some applications might want measure the effect of a set of commands with a different settings. It is possible to override a particular settings using :

    VkResult vkCmdSetPerformanceOverrideINTEL(
        VkCommandBuffer                             commandBuffer,
        const VkPerformanceOverrideInfoINTEL*       pOverrideInfo);

- `commandBuffer` is the command buffer where the override takes place.

- `pOverrideInfo` is a pointer to a VkPerformanceOverrideInfoINTEL structure selecting the parameter to override.

Valid Usage

- `pOverrideInfo` must not be used with a VkPerformanceOverrideTypeINTEL that is not reported available by `vkGetPerformanceParameterINTEL`.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pOverrideInfo` must be a valid pointer to a valid VkPerformanceOverrideInfoINTEL structure

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, compute, or transfer operations

Host Synchronization

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute Transfer |

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_TOO_MANY_OBJECTS`

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

The `VkPerformanceOverrideInfoINTEL` structure is defined as:

    typedef struct VkPerformanceOverrideInfoINTEL {
        VkStructureType                   sType;
        const void*                       pNext;
        VkPerformanceOverrideTypeINTEL    type;
        VkBool32                          enable;
        uint64_t                          parameter;
    } VkPerformanceOverrideInfoINTEL;

- `type` is the particular VkPerformanceOverrideTypeINTEL to set.

- `enable` defines whether the override is enabled.

- `parameter` is a potential required parameter for the override.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PERFORMANCE_OVERRIDE_INFO_INTEL`

- `pNext` must be `NULL`

- `type` must be a valid VkPerformanceOverrideTypeINTEL value

Possible values of VkPerformanceOverrideInfoINTEL::`type`, specifying performance override types, are:

    typedef enum VkPerformanceOverrideTypeINTEL {
        VK_PERFORMANCE_OVERRIDE_TYPE_NULL_HARDWARE_INTEL = 0,
        VK_PERFORMANCE_OVERRIDE_TYPE_FLUSH_GPU_CACHES_INTEL = 1,
        VK_PERFORMANCE_OVERRIDE_TYPE_MAX_ENUM_INTEL = 0x7FFFFFFF
    } VkPerformanceOverrideTypeINTEL;

- `VK_PERFORMANCE_OVERRIDE_TYPE_NULL_HARDWARE_INTEL` turns all rendering operations into noop.

- `VK_PERFORMANCE_OVERRIDE_TYPE_FLUSH_GPU_CACHES_INTEL` stalls the stream of commands until all previously emitted commands have completed and all caches been flushed and invalidated.

Before submitting command buffers containing performance queries commands to a device queue, the application must acquire and set a performance query configuration. The configuration can be released once all command buffers containing performance query commands are not in a pending state.

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkPerformanceConfigurationINTEL)

To acquire a device performance configuration, call:

    VkResult vkAcquirePerformanceConfigurationINTEL(
        VkDevice                                    device,
        const VkPerformanceConfigurationAcquireInfoINTEL* pAcquireInfo,
        VkPerformanceConfigurationINTEL*            pConfiguration);

- `device` is the logical device that the performance query commands will be submitted to.

- `pAcquireInfo` is a pointer to a VkPerformanceConfigurationAcquireInfoINTEL structure, specifying the performance configuration to acquire.

- `pConfiguration` is a pointer to a `VkPerformanceConfigurationINTEL` handle in which the resulting configuration object is returned.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pAcquireInfo` must be a valid pointer to a valid VkPerformanceConfigurationAcquireInfoINTEL structure

- `pConfiguration` must be a valid pointer to a VkPerformanceConfigurationINTEL handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_TOO_MANY_OBJECTS`

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

The `VkPerformanceConfigurationAcquireInfoINTEL` structure is defined as:

    typedef struct VkPerformanceConfigurationAcquireInfoINTEL {
        VkStructureType                        sType;
        const void*                            pNext;
        VkPerformanceConfigurationTypeINTEL    type;
    } VkPerformanceConfigurationAcquireInfoINTEL;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `type` is one of the VkPerformanceConfigurationTypeINTEL type of performance configuration that will be acquired.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PERFORMANCE_CONFIGURATION_ACQUIRE_INFO_INTEL`

- `pNext` must be `NULL`

- `type` must be a valid VkPerformanceConfigurationTypeINTEL value

Possible values of VkPerformanceConfigurationAcquireInfoINTEL::`type`, specifying performance configuration types, are:

    typedef enum VkPerformanceConfigurationTypeINTEL {
        VK_PERFORMANCE_CONFIGURATION_TYPE_COMMAND_QUEUE_METRICS_DISCOVERY_ACTIVATED_INTEL = 0,
        VK_PERFORMANCE_CONFIGURATION_TYPE_MAX_ENUM_INTEL = 0x7FFFFFFF
    } VkPerformanceConfigurationTypeINTEL;

To set a performance configuration, call:

    VkResult vkQueueSetPerformanceConfigurationINTEL(
        VkQueue                                     queue,
        VkPerformanceConfigurationINTEL             configuration);

- `queue` is the queue on which the configuration will be used.

- `configuration` is the configuration to use.

Valid Usage (Implicit)

- `queue` must be a valid VkQueue handle

- `configuration` must be a valid VkPerformanceConfigurationINTEL handle

- Both of `configuration`, and `queue` must have been created, allocated, or retrieved from the same VkDevice

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
- | - | Any | -

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_TOO_MANY_OBJECTS`

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

To release a device performance configuration, call:

    VkResult vkReleasePerformanceConfigurationINTEL(
        VkDevice                                    device,
        VkPerformanceConfigurationINTEL             configuration);

- `device` is the device associated to the configuration object to release.

- `configuration` is the configuration object to release.

Valid Usage

- `configuration` must not be released before all command buffers submitted while the configuration was set are in pending state.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `configuration` must be a valid VkPerformanceConfigurationINTEL handle

- `configuration` must have been created, allocated, or retrieved from `device`

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_TOO_MANY_OBJECTS`

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

## 18. Clear Commands

### 18.1. Clearing Images Outside A Render Pass Instance

Color and depth/stencil images can be cleared outside a render pass instance using vkCmdClearColorImage or vkCmdClearDepthStencilImage, respectively. These commands are only allowed outside of a render pass instance.

To clear one or more subranges of a color image, call:

    void vkCmdClearColorImage(
        VkCommandBuffer                             commandBuffer,
        VkImage                                     image,
        VkImageLayout                               imageLayout,
        const VkClearColorValue*                    pColor,
        uint32_t                                    rangeCount,
        const VkImageSubresourceRange*              pRanges);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `image` is the image to be cleared.

- `imageLayout` specifies the current layout of the image subresource ranges to be cleared, and must be `VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR`, `VK_IMAGE_LAYOUT_GENERAL` or `VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL`.

- `pColor` is a pointer to a VkClearColorValue structure containing the values that the image subresource ranges will be cleared to (see Clear Values below).

- `rangeCount` is the number of image subresource range structures in `pRanges`.

- `pRanges` is a pointer to an array of VkImageSubresourceRange structures describing a range of mipmap levels, array layers, and aspects to be cleared, as described in Image Views.

Each specified range in `pRanges` is cleared to the value specified by `pColor`.

Valid Usage

- The format features of `image` must contain `VK_FORMAT_FEATURE_TRANSFER_DST_BIT`.

- `image` must have been created with `VK_IMAGE_USAGE_TRANSFER_DST_BIT` usage flag

- `image` must not use a format listed in Formats requiring sampler Y′CBCR conversion for `VK_IMAGE_ASPECT_COLOR_BIT` image views

- If `image` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `imageLayout` must specify the layout of the image subresource ranges of `image` specified in `pRanges` at the time this command is executed on a `VkDevice`

- `imageLayout` must be `VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL`, `VK_IMAGE_LAYOUT_GENERAL`, or `VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR`

- The VkImageSubresourceRange::`aspectMask` members of the elements of the `pRanges` array must each only include `VK_IMAGE_ASPECT_COLOR_BIT`

- The VkImageSubresourceRange::`baseMipLevel` members of the elements of the `pRanges` array must each be less than the `mipLevels` specified in VkImageCreateInfo when `image` was created

- For each VkImageSubresourceRange element of `pRanges`, if the `levelCount` member is not `VK_REMAINING_MIP_LEVELS`, then `baseMipLevel` + `levelCount` must be less than the `mipLevels` specified in VkImageCreateInfo when `image` was created

- The VkImageSubresourceRange::`baseArrayLayer` members of the elements of the `pRanges` array must each be less than the `arrayLayers` specified in VkImageCreateInfo when `image` was created

- For each VkImageSubresourceRange element of `pRanges`, if the `layerCount` member is not `VK_REMAINING_ARRAY_LAYERS`, then `baseArrayLayer` + `layerCount` must be less than the `arrayLayers` specified in VkImageCreateInfo when `image` was created

- `image` must not have a compressed or depth/stencil format

- If `commandBuffer` is an unprotected command buffer, then `image` must not be a protected image

- If `commandBuffer` is a protected command buffer, then `image` must not be an unprotected image

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `image` must be a valid VkImage handle

- `imageLayout` must be a valid VkImageLayout value

- `pColor` must be a valid pointer to a valid VkClearColorValue union

- `pRanges` must be a valid pointer to an array of `rangeCount` valid VkImageSubresourceRange structures

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

- This command must only be called outside of a render pass instance

- `rangeCount` must be greater than `0`

- Both of `commandBuffer`, and `image` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Graphics Compute | Transfer

To clear one or more subranges of a depth/stencil image, call:

    void vkCmdClearDepthStencilImage(
        VkCommandBuffer                             commandBuffer,
        VkImage                                     image,
        VkImageLayout                               imageLayout,
        const VkClearDepthStencilValue*             pDepthStencil,
        uint32_t                                    rangeCount,
        const VkImageSubresourceRange*              pRanges);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `image` is the image to be cleared.

- `imageLayout` specifies the current layout of the image subresource ranges to be cleared, and must be `VK_IMAGE_LAYOUT_GENERAL` or `VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL`.

- `pDepthStencil` is a pointer to a VkClearDepthStencilValue structure containing the values that the depth and stencil image subresource ranges will be cleared to (see Clear Values below).

- `rangeCount` is the number of image subresource range structures in `pRanges`.

- `pRanges` is a pointer to an array of VkImageSubresourceRange structures describing a range of mipmap levels, array layers, and aspects to be cleared, as described in Image Views.

Valid Usage

- The format features of `image` must contain `VK_FORMAT_FEATURE_TRANSFER_DST_BIT`.

- If any element of `pRanges.aspect` includes `VK_IMAGE_ASPECT_STENCIL_BIT`, and `image` was created with separate stencil usage, `VK_IMAGE_USAGE_TRANSFER_DST_BIT` must have been included in the VkImageStencilUsageCreateInfo::`stencilUsage` used to create `image`

- If any element of `pRanges.aspect` includes `VK_IMAGE_ASPECT_STENCIL_BIT`, and `image` was not created with separate stencil usage, `VK_IMAGE_USAGE_TRANSFER_DST_BIT` must have been included in the VkImageCreateInfo::`usage` used to create `image`

- If any element of `pRanges.aspect` includes `VK_IMAGE_ASPECT_DEPTH_BIT`, `VK_IMAGE_USAGE_TRANSFER_DST_BIT` must have been included in the VkImageCreateInfo::`usage` used to create `image`

- If `image` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `imageLayout` must specify the layout of the image subresource ranges of `image` specified in `pRanges` at the time this command is executed on a `VkDevice`

- `imageLayout` must be either of `VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL` or `VK_IMAGE_LAYOUT_GENERAL`

- The VkImageSubresourceRange::`aspectMask` member of each element of the `pRanges` array must not include bits other than `VK_IMAGE_ASPECT_DEPTH_BIT` or `VK_IMAGE_ASPECT_STENCIL_BIT`

- If the `image`’s format does not have a stencil component, then the VkImageSubresourceRange::`aspectMask` member of each element of the `pRanges` array must not include the `VK_IMAGE_ASPECT_STENCIL_BIT` bit

- If the `image`’s format does not have a depth component, then the VkImageSubresourceRange::`aspectMask` member of each element of the `pRanges` array must not include the `VK_IMAGE_ASPECT_DEPTH_BIT` bit

- The VkImageSubresourceRange::`baseMipLevel` members of the elements of the `pRanges` array must each be less than the `mipLevels` specified in VkImageCreateInfo when `image` was created

- For each VkImageSubresourceRange element of `pRanges`, if the `levelCount` member is not `VK_REMAINING_MIP_LEVELS`, then `baseMipLevel` + `levelCount` must be less than the `mipLevels` specified in VkImageCreateInfo when `image` was created

- The VkImageSubresourceRange::`baseArrayLayer` members of the elements of the `pRanges` array must each be less than the `arrayLayers` specified in VkImageCreateInfo when `image` was created

- For each VkImageSubresourceRange element of `pRanges`, if the `layerCount` member is not `VK_REMAINING_ARRAY_LAYERS`, then `baseArrayLayer` + `layerCount` must be less than the `arrayLayers` specified in VkImageCreateInfo when `image` was created

- `image` must have a depth/stencil format

- If `commandBuffer` is an unprotected command buffer, then `image` must not be a protected image

- If `commandBuffer` is a protected command buffer, then `image` must not be an unprotected image

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `image` must be a valid VkImage handle

- `imageLayout` must be a valid VkImageLayout value

- `pDepthStencil` must be a valid pointer to a valid VkClearDepthStencilValue structure

- `pRanges` must be a valid pointer to an array of `rangeCount` valid VkImageSubresourceRange structures

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- This command must only be called outside of a render pass instance

- `rangeCount` must be greater than `0`

- Both of `commandBuffer`, and `image` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Graphics | Transfer

Clears outside render pass instances are treated as transfer operations for the purposes of memory barriers.

### 18.2. Clearing Images Inside A Render Pass Instance

To clear one or more regions of color and depth/stencil attachments inside a render pass instance, call:

    void vkCmdClearAttachments(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    attachmentCount,
        const VkClearAttachment*                    pAttachments,
        uint32_t                                    rectCount,
        const VkClearRect*                          pRects);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `attachmentCount` is the number of entries in the `pAttachments` array.

- `pAttachments` is a pointer to an array of VkClearAttachment structures defining the attachments to clear and the clear values to use. If any attachment to be cleared in the current subpass is `VK_ATTACHMENT_UNUSED`, then the clear has no effect on that attachment.

- `rectCount` is the number of entries in the `pRects` array.

- `pRects` is a pointer to an array of VkClearRect structures defining regions within each selected attachment to clear.

`vkCmdClearAttachments` can clear multiple regions of each attachment used in the current subpass of a render pass instance. This command must be called only inside a render pass instance, and implicitly selects the images to clear based on the current framebuffer attachments and the command parameters.

If the render pass has a fragment density map attachment, clears follow the operations of fragment density maps as if each clear region was a primitive which generates fragments. The clear color is applied to all pixels inside each fragment’s area regardless if the pixels lie outside of the clear region. Clears may have a different set of supported fragment areas than draws.

Unlike other clear commands, vkCmdClearAttachments executes as a drawing command, rather than a transfer command, with writes performed by it executing in rasterization order. Clears to color attachments are executed as color attachment writes, by the `VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT` stage. Clears to depth/stencil attachments are executed as depth writes and writes by the `VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT` and `VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT` stages.

Valid Usage

- If the `aspectMask` member of any element of `pAttachments` contains `VK_IMAGE_ASPECT_COLOR_BIT`, then the `colorAttachment` member of that element must either refer to a color attachment which is `VK_ATTACHMENT_UNUSED`, or must be a valid color attachment.

- If the `aspectMask` member of any element of `pAttachments` contains `VK_IMAGE_ASPECT_DEPTH_BIT`, then the current subpass' depth/stencil attachment must either be `VK_ATTACHMENT_UNUSED`, or must have a depth component

- If the `aspectMask` member of any element of `pAttachments` contains `VK_IMAGE_ASPECT_STENCIL_BIT`, then the current subpass' depth/stencil attachment must either be `VK_ATTACHMENT_UNUSED`, or must have a stencil component

- The `rect` member of each element of `pRects` must have an `extent.width` greater than `0`

- The `rect` member of each element of `pRects` must have an `extent.height` greater than `0`

- The rectangular region specified by each element of `pRects` must be contained within the render area of the current render pass instance

- The layers specified by each element of `pRects` must be contained within every attachment that `pAttachments` refers to

- The `layerCount` member of each element of `pRects` must not be `0`

- If `commandBuffer` is an unprotected command buffer, then each attachment to be cleared must not be a protected image.

- If `commandBuffer` is a protected command buffer, then each attachment to be cleared must not be an unprotected image.

- If the render pass instance this is recorded in uses multiview, then `baseArrayLayer` must be zero and `layerCount` must be one.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pAttachments` must be a valid pointer to an array of `attachmentCount` valid VkClearAttachment structures

- `pRects` must be a valid pointer to an array of `rectCount` VkClearRect structures

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- This command must only be called inside of a render pass instance

- `attachmentCount` must be greater than `0`

- `rectCount` must be greater than `0`

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Inside | Graphics | Graphics

The `VkClearRect` structure is defined as:

    typedef struct VkClearRect {
        VkRect2D    rect;
        uint32_t    baseArrayLayer;
        uint32_t    layerCount;
    } VkClearRect;

- `rect` is the two-dimensional region to be cleared.

- `baseArrayLayer` is the first layer to be cleared.

- `layerCount` is the number of layers to clear.

The layers [`baseArrayLayer`, `baseArrayLayer` + `layerCount`) counting from the base layer of the attachment image view are cleared.

The `VkClearAttachment` structure is defined as:

    typedef struct VkClearAttachment {
        VkImageAspectFlags    aspectMask;
        uint32_t              colorAttachment;
        VkClearValue          clearValue;
    } VkClearAttachment;

- `aspectMask` is a mask selecting the color, depth and/or stencil aspects of the attachment to be cleared.

- `colorAttachment` is only meaningful if `VK_IMAGE_ASPECT_COLOR_BIT` is set in `aspectMask`, in which case it is an index to the `pColorAttachments` array in the VkSubpassDescription structure of the current subpass which selects the color attachment to clear.

- `clearValue` is the color or depth/stencil value to clear the attachment to, as described in Clear Values below.

No memory barriers are needed between `vkCmdClearAttachments` and preceding or subsequent draw or attachment clear commands in the same subpass.

The `vkCmdClearAttachments` command is not affected by the bound pipeline state.

Attachments can also be cleared at the beginning of a render pass instance by setting `loadOp` (or `stencilLoadOp`) of VkAttachmentDescription to `VK_ATTACHMENT_LOAD_OP_CLEAR`, as described for vkCreateRenderPass.

Valid Usage

- If `aspectMask` includes `VK_IMAGE_ASPECT_COLOR_BIT`, it must not include `VK_IMAGE_ASPECT_DEPTH_BIT` or `VK_IMAGE_ASPECT_STENCIL_BIT`

- `aspectMask` must not include `VK_IMAGE_ASPECT_METADATA_BIT`

- `aspectMask` must not include `VK_IMAGE_ASPECT_MEMORY_PLANE_i_BIT_EXT` for any index `i`.

- `clearValue` must be a valid `VkClearValue` union

Valid Usage (Implicit)

- `aspectMask` must be a valid combination of VkImageAspectFlagBits values

- `aspectMask` must not be `0`

### 18.3. Clear Values

The `VkClearColorValue` structure is defined as:

    typedef union VkClearColorValue {
        float       float32[4];
        int32_t     int32[4];
        uint32_t    uint32[4];
    } VkClearColorValue;

- `float32` are the color clear values when the format of the image or attachment is one of the formats in the Interpretation of Numeric Format table other than signed integer (`SINT`) or unsigned integer (`UINT`). Floating point values are automatically converted to the format of the image, with the clear value being treated as linear if the image is sRGB.

- `int32` are the color clear values when the format of the image or attachment is signed integer (`SINT`). Signed integer values are converted to the format of the image by casting to the smaller type (with negative 32-bit values mapping to negative values in the smaller type). If the integer clear value is not representable in the target type (e.g. would overflow in conversion to that type), the clear value is undefined.

- `uint32` are the color clear values when the format of the image or attachment is unsigned integer (`UINT`). Unsigned integer values are converted to the format of the image by casting to the integer type with fewer bits.

The four array elements of the clear color map to R, G, B, and A components of image formats, in order.

If the image has more than one sample, the same value is written to all samples for any pixels being cleared.

The `VkClearDepthStencilValue` structure is defined as:

    typedef struct VkClearDepthStencilValue {
        float       depth;
        uint32_t    stencil;
    } VkClearDepthStencilValue;

- `depth` is the clear value for the depth aspect of the depth/stencil attachment. It is a floating-point value which is automatically converted to the attachment’s format.

- `stencil` is the clear value for the stencil aspect of the depth/stencil attachment. It is a 32-bit integer value which is converted to the attachment’s format by taking the appropriate number of LSBs.

Valid Usage

- Unless the `VK_EXT_depth_range_unrestricted` extension is enabled `depth` must be between `0.0` and `1.0`, inclusive

The `VkClearValue` union is defined as:

    typedef union VkClearValue {
        VkClearColorValue           color;
        VkClearDepthStencilValue    depthStencil;
    } VkClearValue;

- `color` specifies the color image clear values to use when clearing a color image or attachment.

- `depthStencil` specifies the depth and stencil clear values to use when clearing a depth/stencil image or attachment.

This union is used where part of the API requires either color or depth/stencil clear values, depending on the attachment, and defines the initial clear values in the VkRenderPassBeginInfo structure.

### 18.4. Filling Buffers

To clear buffer data, call:

    void vkCmdFillBuffer(
        VkCommandBuffer                             commandBuffer,
        VkBuffer                                    dstBuffer,
        VkDeviceSize                                dstOffset,
        VkDeviceSize                                size,
        uint32_t                                    data);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `dstBuffer` is the buffer to be filled.

- `dstOffset` is the byte offset into the buffer at which to start filling, and must be a multiple of 4.

- `size` is the number of bytes to fill, and must be either a multiple of 4, or `VK_WHOLE_SIZE` to fill the range from `offset` to the end of the buffer. If `VK_WHOLE_SIZE` is used and the remaining size of the buffer is not a multiple of 4, then the nearest smaller multiple is used.

- `data` is the 4-byte word written repeatedly to the buffer to fill `size` bytes of data. The data word is written to memory according to the host endianness.

`vkCmdFillBuffer` is treated as “transfer” operation for the purposes of synchronization barriers. The `VK_BUFFER_USAGE_TRANSFER_DST_BIT` must be specified in `usage` of `VkBufferCreateInfo` in order for the buffer to be compatible with `vkCmdFillBuffer`.

Valid Usage

- `dstOffset` must be less than the size of `dstBuffer`

- `dstOffset` must be a multiple of `4`

- If `size` is not equal to `VK_WHOLE_SIZE`, `size` must be greater than `0`

- If `size` is not equal to `VK_WHOLE_SIZE`, `size` must be less than or equal to the size of `dstBuffer` minus `dstOffset`

- If `size` is not equal to `VK_WHOLE_SIZE`, `size` must be a multiple of `4`

- `dstBuffer` must have been created with `VK_BUFFER_USAGE_TRANSFER_DST_BIT` usage flag

- If `dstBuffer` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- If `commandBuffer` is an unprotected command buffer, then `dstBuffer` must not be a protected buffer

- If `commandBuffer` is a protected command buffer, then `dstBuffer` must not be an unprotected buffer

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `dstBuffer` must be a valid VkBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support transfer, graphics or compute operations

- This command must only be called outside of a render pass instance

- Both of `commandBuffer`, and `dstBuffer` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Transfer Graphics Compute | Transfer

### 18.5. Updating Buffers

To update buffer data inline in a command buffer, call:

    void vkCmdUpdateBuffer(
        VkCommandBuffer                             commandBuffer,
        VkBuffer                                    dstBuffer,
        VkDeviceSize                                dstOffset,
        VkDeviceSize                                dataSize,
        const void*                                 pData);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `dstBuffer` is a handle to the buffer to be updated.

- `dstOffset` is the byte offset into the buffer to start updating, and must be a multiple of 4.

- `dataSize` is the number of bytes to update, and must be a multiple of 4.

- `pData` is a pointer to the source data for the buffer update, and must be at least `dataSize` bytes in size.

`dataSize` must be less than or equal to 65536 bytes. For larger updates, applications can use buffer to buffer copies.

| Note Buffer updates performed with `vkCmdUpdateBuffer` first copy the data into command buffer memory when the command is recorded (which requires additional storage and may incur an additional allocation), and then copy the data from the command buffer into `dstBuffer` when the command is executed on a device. The additional cost of this functionality compared to buffer to buffer copies means it is only recommended for very small amounts of data, and is why it is limited to only 65536 bytes. Applications can work around this by issuing multiple `vkCmdUpdateBuffer` commands to different ranges of the same buffer, but it is strongly recommended that they should not.

The source data is copied from the user pointer to the command buffer when the command is called.

`vkCmdUpdateBuffer` is only allowed outside of a render pass. This command is treated as “transfer” operation, for the purposes of synchronization barriers. The `VK_BUFFER_USAGE_TRANSFER_DST_BIT` must be specified in `usage` of VkBufferCreateInfo in order for the buffer to be compatible with `vkCmdUpdateBuffer`.

Valid Usage

- `dstOffset` must be less than the size of `dstBuffer`

- `dataSize` must be less than or equal to the size of `dstBuffer` minus `dstOffset`

- `dstBuffer` must have been created with `VK_BUFFER_USAGE_TRANSFER_DST_BIT` usage flag

- If `dstBuffer` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `dstOffset` must be a multiple of `4`

- `dataSize` must be less than or equal to `65536`

- `dataSize` must be a multiple of `4`

- If `commandBuffer` is an unprotected command buffer, then `dstBuffer` must not be a protected buffer

- If `commandBuffer` is a protected command buffer, then `dstBuffer` must not be an unprotected buffer

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `dstBuffer` must be a valid VkBuffer handle

- `pData` must be a valid pointer to an array of `dataSize` bytes

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support transfer, graphics, or compute operations

- This command must only be called outside of a render pass instance

- `dataSize` must be greater than `0`

- Both of `commandBuffer`, and `dstBuffer` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Transfer Graphics Compute | Transfer

| Note The `pData` parameter was of type `uint32_t`* instead of `void`* prior to version 1.0.19 of the Specification and VK_HEADER_VERSION 19 of the Vulkan Header Files. This was a historical anomaly, as the source data may be of other types.

## 19. Copy Commands

An application can copy buffer and image data using several methods depending on the type of data transfer. Data can be copied between buffer objects with `vkCmdCopyBuffer` and a portion of an image can be copied to another image with `vkCmdCopyImage`. Image data can also be copied to and from buffer memory using `vkCmdCopyImageToBuffer` and `vkCmdCopyBufferToImage`. Image data can be blitted (with or without scaling and filtering) with `vkCmdBlitImage`. Multisampled images can be resolved to a non-multisampled image with `vkCmdResolveImage`.

### 19.1. Common Operation

The following valid usage rules apply to all copy commands:

- Copy commands must be recorded outside of a render pass instance.

- The set of all bytes bound to all the source regions must not overlap the set of all bytes bound to the destination regions.

- The set of all bytes bound to each destination region must not overlap the set of all bytes bound to another destination region.

- Copy regions must be non-empty.

- Regions must not extend outside the bounds of the buffer or image level, except that regions of compressed images can extend as far as the dimension of the image level rounded up to a complete compressed texel block.

- Source image subresources must be in either the `VK_IMAGE_LAYOUT_GENERAL` or `VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL` layout. Destination image subresources must be in the `VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR`, `VK_IMAGE_LAYOUT_GENERAL` or `VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL` layout. As a consequence, if an image subresource is used as both source and destination of a copy, it must be in the `VK_IMAGE_LAYOUT_GENERAL` layout.

- Source images must have `VK_FORMAT_FEATURE_TRANSFER_SRC_BIT` in their format features.

- Destination images must have `VK_FORMAT_FEATURE_TRANSFER_DST_BIT` in their format features.

- Source buffers must have been created with the `VK_BUFFER_USAGE_TRANSFER_SRC_BIT` usage bit enabled and destination buffers must have been created with the `VK_BUFFER_USAGE_TRANSFER_DST_BIT` usage bit enabled.

- If the stencil aspect of source image is accessed, and the source image was not created with separate stencil usage, the source image must have been created with `VK_IMAGE_USAGE_TRANSFER_SRC_BIT` set in VkImageCreateInfo::`usage`

- If the stencil aspect of destination image is accessed, and the destination image was not created with separate stencil usage, the destination image must have been created with `VK_IMAGE_USAGE_TRANSFER_DST_BIT` set in VkImageCreateInfo::`usage`

- If the stencil aspect of source image is accessed, and the source image was created with separate stencil usage, the source image must have been created with `VK_IMAGE_USAGE_TRANSFER_SRC_BIT` set in VkImageStencilUsageCreateInfo::`stencilUsage`

- If the stencil aspect of destination image is accessed, and the destination image was created with separate stencil usage, the destination image must have been created with `VK_IMAGE_USAGE_TRANSFER_DST_BIT` set in VkImageStencilUsageCreateInfo::`stencilUsage`

- If non-stencil aspects of a source image are accessed, the source image must have been created with `VK_IMAGE_USAGE_TRANSFER_SRC_BIT` set in VkImageCreateInfo::`usage`

- If non-stencil aspects of a source image are accessed, the source image must have been created with `VK_IMAGE_USAGE_TRANSFER_DST_BIT` set in VkImageCreateInfo::`usage`

All copy commands are treated as “transfer” operations for the purposes of synchronization barriers.

All copy commands that have a source format with an X component in its format description read undefined values from those bits.

All copy commands that have a destination format with an X component in its format description write undefined values to those bits.

### 19.2. Copying Data Between Buffers

To copy data between buffer objects, call:

    void vkCmdCopyBuffer(
        VkCommandBuffer                             commandBuffer,
        VkBuffer                                    srcBuffer,
        VkBuffer                                    dstBuffer,
        uint32_t                                    regionCount,
        const VkBufferCopy*                         pRegions);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `srcBuffer` is the source buffer.

- `dstBuffer` is the destination buffer.

- `regionCount` is the number of regions to copy.

- `pRegions` is a pointer to an array of VkBufferCopy structures specifying the regions to copy.

Each region in `pRegions` is copied from the source buffer to the same region of the destination buffer. `srcBuffer` and `dstBuffer` can be the same buffer or alias the same memory, but the resulting values are undefined if the copy regions overlap in memory.

Valid Usage

- The `srcOffset` member of each element of `pRegions` must be less than the size of `srcBuffer`

- The `dstOffset` member of each element of `pRegions` must be less than the size of `dstBuffer`

- The `size` member of each element of `pRegions` must be less than or equal to the size of `srcBuffer` minus `srcOffset`

- The `size` member of each element of `pRegions` must be less than or equal to the size of `dstBuffer` minus `dstOffset`

- The union of the source regions, and the union of the destination regions, specified by the elements of `pRegions`, must not overlap in memory

- `srcBuffer` must have been created with `VK_BUFFER_USAGE_TRANSFER_SRC_BIT` usage flag

- If `srcBuffer` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `dstBuffer` must have been created with `VK_BUFFER_USAGE_TRANSFER_DST_BIT` usage flag

- If `dstBuffer` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- If `commandBuffer` is an unprotected command buffer, then `srcBuffer` must not be a protected buffer

- If `commandBuffer` is an unprotected command buffer, then `dstBuffer` must not be a protected buffer

- If `commandBuffer` is a protected command buffer, then `dstBuffer` must not be an unprotected buffer

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `srcBuffer` must be a valid VkBuffer handle

- `dstBuffer` must be a valid VkBuffer handle

- `pRegions` must be a valid pointer to an array of `regionCount` valid VkBufferCopy structures

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support transfer, graphics, or compute operations

- This command must only be called outside of a render pass instance

- `regionCount` must be greater than `0`

- Each of `commandBuffer`, `dstBuffer`, and `srcBuffer` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Transfer Graphics Compute | Transfer

The `VkBufferCopy` structure is defined as:

    typedef struct VkBufferCopy {
        VkDeviceSize    srcOffset;
        VkDeviceSize    dstOffset;
        VkDeviceSize    size;
    } VkBufferCopy;

- `srcOffset` is the starting offset in bytes from the start of `srcBuffer`.

- `dstOffset` is the starting offset in bytes from the start of `dstBuffer`.

- `size` is the number of bytes to copy.

Valid Usage

- The `size` must be greater than `0`

### 19.3. Copying Data Between Images

`vkCmdCopyImage` performs image copies in a similar manner to a host memcpy. It does not perform general-purpose conversions such as scaling, resizing, blending, color-space conversion, or format conversions. Rather, it simply copies raw image data. `vkCmdCopyImage` can copy between images with different formats, provided the formats are compatible as defined below.

To copy data between image objects, call:

    void vkCmdCopyImage(
        VkCommandBuffer                             commandBuffer,
        VkImage                                     srcImage,
        VkImageLayout                               srcImageLayout,
        VkImage                                     dstImage,
        VkImageLayout                               dstImageLayout,
        uint32_t                                    regionCount,
        const VkImageCopy*                          pRegions);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `srcImage` is the source image.

- `srcImageLayout` is the current layout of the source image subresource.

- `dstImage` is the destination image.

- `dstImageLayout` is the current layout of the destination image subresource.

- `regionCount` is the number of regions to copy.

- `pRegions` is a pointer to an array of VkImageCopy structures specifying the regions to copy.

Each region in `pRegions` is copied from the source image to the same region of the destination image. `srcImage` and `dstImage` can be the same image or alias the same memory.

The formats of `srcImage` and `dstImage` must be compatible. Formats are compatible if they share the same class, as shown in the Compatible Formats table. Depth/stencil formats must match exactly.

If the format of `srcImage` or `dstImage` is a multi-planar image format, regions of each plane to be copied must be specified separately using the `srcSubresource` and `dstSubresource` members of the VkImageCopy structure. In this case, the `aspectMask` of the `srcSubresource` or `dstSubresource` that refers to the multi-planar image must be `VK_IMAGE_ASPECT_PLANE_0_BIT`, `VK_IMAGE_ASPECT_PLANE_1_BIT`, or `VK_IMAGE_ASPECT_PLANE_2_BIT`. For the purposes of `vkCmdCopyImage`, each plane of a multi-planar image is treated as having the format listed in Compatible formats of planes of multi-planar formats for the plane identified by the `aspectMask` of the corresponding subresource. This applies both to VkFormat and to coordinates used in the copy, which correspond to texels in the plane rather than how these texels map to coordinates in the image as a whole.

| Note For example, the `VK_IMAGE_ASPECT_PLANE_1_BIT` plane of a `VK_FORMAT_G8_B8R8_2PLANE_420_UNORM` image is compatible with an image of format `VK_FORMAT_R8G8_UNORM` and (less usefully) with the `VK_IMAGE_ASPECT_PLANE_0_BIT` plane of an image of format `VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_420_UNORM_3PACK16`, as each texel is 2 bytes in size.

`vkCmdCopyImage` allows copying between size-compatible compressed and uncompressed internal formats. Formats are size-compatible if the texel block size of the uncompressed format is equal to the texel block size of the compressed format. Such a copy does not perform on-the-fly compression or decompression. When copying from an uncompressed format to a compressed format, each texel of uncompressed data of the source image is copied as a raw value to the corresponding compressed texel block of the destination image. When copying from a compressed format to an uncompressed format, each compressed texel block of the source image is copied as a raw value to the corresponding texel of uncompressed data in the destination image. Thus, for example, it is legal to copy between a 128-bit uncompressed format and a compressed format which has a 128-bit sized compressed texel block representing 4×4 texels (using 8 bits per texel), or between a 64-bit uncompressed format and a compressed format which has a 64-bit sized compressed texel block representing 4×4 texels (using 4 bits per texel).

When copying between compressed and uncompressed formats the `extent` members represent the texel dimensions of the source image and not the destination. When copying from a compressed image to an uncompressed image the image texel dimensions written to the uncompressed image will be source extent divided by the compressed texel block dimensions. When copying from an uncompressed image to a compressed image the image texel dimensions written to the compressed image will be the source extent multiplied by the compressed texel block dimensions. In both cases the number of bytes read and the number of bytes written will be identical.

Copying to or from block-compressed images is typically done in multiples of the compressed texel block size. For this reason the `extent` must be a multiple of the compressed texel block dimension. There is one exception to this rule which is required to handle compressed images created with dimensions that are not a multiple of the compressed texel block dimensions: if the `srcImage` is compressed, then:

- If `extent.width` is not a multiple of the compressed texel block width, then (`extent.width` + `srcOffset.x`) must equal the image subresource width.

- If `extent.height` is not a multiple of the compressed texel block height, then (`extent.height` + `srcOffset.y`) must equal the image subresource height.

- If `extent.depth` is not a multiple of the compressed texel block depth, then (`extent.depth` + `srcOffset.z`) must equal the image subresource depth.

Similarly, if the `dstImage` is compressed, then:

- If `extent.width` is not a multiple of the compressed texel block width, then (`extent.width` + `dstOffset.x`) must equal the image subresource width.

- If `extent.height` is not a multiple of the compressed texel block height, then (`extent.height` + `dstOffset.y`) must equal the image subresource height.

- If `extent.depth` is not a multiple of the compressed texel block depth, then (`extent.depth` + `dstOffset.z`) must equal the image subresource depth.

This allows the last compressed texel block of the image in each non-multiple dimension to be included as a source or destination of the copy.

“`_422`” image formats that are not multi-planar are treated as having a 2×1 compressed texel block for the purposes of these rules.

`vkCmdCopyImage` can be used to copy image data between multisample images, but both images must have the same number of samples.

Valid Usage

- The union of all source regions, and the union of all destination regions, specified by the elements of `pRegions`, must not overlap in memory

- The format features of `srcImage` must contain `VK_FORMAT_FEATURE_TRANSFER_SRC_BIT`.

- `srcImage` must have been created with `VK_IMAGE_USAGE_TRANSFER_SRC_BIT` usage flag

- If `srcImage` is non-sparse then the image or disjoint plane to be copied must be bound completely and contiguously to a single `VkDeviceMemory` object

- `srcImageLayout` must specify the layout of the image subresources of `srcImage` specified in `pRegions` at the time this command is executed on a `VkDevice`

- `srcImageLayout` must be `VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL`, `VK_IMAGE_LAYOUT_GENERAL`, or `VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR`

- The format features of `dstImage` must contain `VK_FORMAT_FEATURE_TRANSFER_DST_BIT`.

- `dstImage` must have been created with `VK_IMAGE_USAGE_TRANSFER_DST_BIT` usage flag

- If `dstImage` is non-sparse then the image or disjoint plane that is the destination of the copy must be bound completely and contiguously to a single `VkDeviceMemory` object

- `dstImageLayout` must specify the layout of the image subresources of `dstImage` specified in `pRegions` at the time this command is executed on a `VkDevice`

- `dstImageLayout` must be `VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL`, `VK_IMAGE_LAYOUT_GENERAL`, or `VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR`

- If the VkFormat of each of `srcImage` and `dstImage` is not a multi-planar format, the VkFormat of each of `srcImage` and `dstImage` must be compatible, as defined above

- In a copy to or from a plane of a multi-planar image, the VkFormat of the image and plane must be compatible according to the description of compatible planes for the plane being copied

- The sample count of `srcImage` and `dstImage` must match

- If `commandBuffer` is an unprotected command buffer, then `srcImage` must not be a protected image

- If `commandBuffer` is an unprotected command buffer, then `dstImage` must not be a protected image

- If `commandBuffer` is a protected command buffer, then `dstImage` must not be an unprotected image

- The `srcSubresource.mipLevel` member of each element of `pRegions` must be less than the `mipLevels` specified in VkImageCreateInfo when `srcImage` was created

- The `dstSubresource.mipLevel` member of each element of `pRegions` must be less than the `mipLevels` specified in VkImageCreateInfo when `dstImage` was created

- The `srcSubresource.baseArrayLayer` + `srcSubresource.layerCount` of each element of `pRegions` must be less than or equal to the `arrayLayers` specified in VkImageCreateInfo when `srcImage` was created

- The `dstSubresource.baseArrayLayer` + `dstSubresource.layerCount` of each element of `pRegions` must be less than or equal to the `arrayLayers` specified in VkImageCreateInfo when `dstImage` was created

- The `srcOffset` and `extent` members of each element of `pRegions` must respect the image transfer granularity requirements of `commandBuffer`’s command pool’s queue family, as described in VkQueueFamilyProperties

- The `dstOffset` and `extent` members of each element of `pRegions` must respect the image transfer granularity requirements of `commandBuffer`’s command pool’s queue family, as described in VkQueueFamilyProperties

- `dstImage` and `srcImage` must not have been created with `flags` containing `VK_IMAGE_CREATE_SUBSAMPLED_BIT_EXT`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `srcImage` must be a valid VkImage handle

- `srcImageLayout` must be a valid VkImageLayout value

- `dstImage` must be a valid VkImage handle

- `dstImageLayout` must be a valid VkImageLayout value

- `pRegions` must be a valid pointer to an array of `regionCount` valid VkImageCopy structures

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support transfer, graphics, or compute operations

- This command must only be called outside of a render pass instance

- `regionCount` must be greater than `0`

- Each of `commandBuffer`, `dstImage`, and `srcImage` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Transfer Graphics Compute | Transfer

The `VkImageCopy` structure is defined as:

    typedef struct VkImageCopy {
        VkImageSubresourceLayers    srcSubresource;
        VkOffset3D                  srcOffset;
        VkImageSubresourceLayers    dstSubresource;
        VkOffset3D                  dstOffset;
        VkExtent3D                  extent;
    } VkImageCopy;

- `srcSubresource` and `dstSubresource` are VkImageSubresourceLayers structures specifying the image subresources of the images used for the source and destination image data, respectively.

- `srcOffset` and `dstOffset` select the initial `x`, `y`, and `z` offsets in texels of the sub-regions of the source and destination image data.

- `extent` is the size in texels of the image to copy in `width`, `height` and `depth`.

For `VK_IMAGE_TYPE_3D` images, copies are performed slice by slice starting with the `z` member of the `srcOffset` or `dstOffset`, and copying `depth` slices. For images with multiple layers, copies are performed layer by layer starting with the `baseArrayLayer` member of the `srcSubresource` or `dstSubresource` and copying `layerCount` layers. Image data can be copied between images with different image types. If one image is `VK_IMAGE_TYPE_3D` and the other image is `VK_IMAGE_TYPE_2D` with multiple layers, then each slice is copied to or from a different layer.

Copies involving a multi-planar image format specify the region to be copied in terms of the plane to be copied, not the coordinates of the multi-planar image. This means that copies accessing the R/B planes of “`_422`” format images must fit the copied region within half the `width` of the parent image, and that copies accessing the R/B planes of “`_420`” format images must fit the copied region within half the `width` and `height` of the parent image.

Valid Usage

- If neither the calling command’s `srcImage` nor the calling command’s `dstImage` has a multi-planar image format then the `aspectMask` member of `srcSubresource` and `dstSubresource` must match

- If the calling command’s `srcImage` has a VkFormat with two planes then the `srcSubresource` `aspectMask` must be `VK_IMAGE_ASPECT_PLANE_0_BIT` or `VK_IMAGE_ASPECT_PLANE_1_BIT`

- If the calling command’s `srcImage` has a VkFormat with three planes then the `srcSubresource` `aspectMask` must be `VK_IMAGE_ASPECT_PLANE_0_BIT`, `VK_IMAGE_ASPECT_PLANE_1_BIT`, or `VK_IMAGE_ASPECT_PLANE_2_BIT`

- If the calling command’s `dstImage` has a VkFormat with two planes then the `dstSubresource` `aspectMask` must be `VK_IMAGE_ASPECT_PLANE_0_BIT` or `VK_IMAGE_ASPECT_PLANE_1_BIT`

- If the calling command’s `dstImage` has a VkFormat with three planes then the `dstSubresource` `aspectMask` must be `VK_IMAGE_ASPECT_PLANE_0_BIT`, `VK_IMAGE_ASPECT_PLANE_1_BIT`, or `VK_IMAGE_ASPECT_PLANE_2_BIT`

- If the calling command’s `srcImage` has a multi-planar image format and the `dstImage` does not have a multi-planar image format, the `dstSubresource` `aspectMask` must be `VK_IMAGE_ASPECT_COLOR_BIT`

- If the calling command’s `dstImage` has a multi-planar image format and the `srcImage` does not have a multi-planar image format, the `srcSubresource` `aspectMask` must be `VK_IMAGE_ASPECT_COLOR_BIT`

- The number of slices of the `extent` (for 3D) or layers of the `srcSubresource` (for non-3D) must match the number of slices of the `extent` (for 3D) or layers of the `dstSubresource` (for non-3D)

- If either of the calling command’s `srcImage` or `dstImage` parameters are of VkImageType `VK_IMAGE_TYPE_3D`, the `baseArrayLayer` and `layerCount` members of the corresponding subresource must be `0` and `1`, respectively

- The `aspectMask` member of `srcSubresource` must specify aspects present in the calling command’s `srcImage`

- The `aspectMask` member of `dstSubresource` must specify aspects present in the calling command’s `dstImage`

- `srcOffset.x` and (`extent.width` + `srcOffset.x`) must both be greater than or equal to `0` and less than or equal to the source image subresource width

- `srcOffset.y` and (`extent.height` + `srcOffset.y`) must both be greater than or equal to `0` and less than or equal to the source image subresource height

- If the calling command’s `srcImage` is of type `VK_IMAGE_TYPE_1D`, then `srcOffset.y` must be `0` and `extent.height` must be `1`.

- `srcOffset.z` and (`extent.depth` + `srcOffset.z`) must both be greater than or equal to `0` and less than or equal to the source image subresource depth

- If the calling command’s `srcImage` is of type `VK_IMAGE_TYPE_1D`, then `srcOffset.z` must be `0` and `extent.depth` must be `1`.

- If the calling command’s `dstImage` is of type `VK_IMAGE_TYPE_1D`, then `dstOffset.z` must be `0` and `extent.depth` must be `1`.

- If the calling command’s `srcImage` is of type `VK_IMAGE_TYPE_2D`, then `srcOffset.z` must be `0`.

- If the calling command’s `dstImage` is of type `VK_IMAGE_TYPE_2D`, then `dstOffset.z` must be `0`.

- If both `srcImage` and `dstImage` are of type `VK_IMAGE_TYPE_2D` then `extent.depth` must be `1`.

- If the calling command’s `srcImage` is of type `VK_IMAGE_TYPE_2D`, and the `dstImage` is of type `VK_IMAGE_TYPE_3D`, then `extent.depth` must equal to the `layerCount` member of `srcSubresource`.

- If the calling command’s `dstImage` is of type `VK_IMAGE_TYPE_2D`, and the `srcImage` is of type `VK_IMAGE_TYPE_3D`, then `extent.depth` must equal to the `layerCount` member of `dstSubresource`.

- `dstOffset.x` and (`extent.width` + `dstOffset.x`) must both be greater than or equal to `0` and less than or equal to the destination image subresource width

- `dstOffset.y` and (`extent.height` + `dstOffset.y`) must both be greater than or equal to `0` and less than or equal to the destination image subresource height

- If the calling command’s `dstImage` is of type `VK_IMAGE_TYPE_1D`, then `dstOffset.y` must be `0` and `extent.height` must be `1`.

- `dstOffset.z` and (`extent.depth` + `dstOffset.z`) must both be greater than or equal to `0` and less than or equal to the destination image subresource depth

- If the calling command’s `srcImage` is a compressed image, or a single-plane, “`_422`” image format, all members of `srcOffset` must be a multiple of the corresponding dimensions of the compressed texel block

- If the calling command’s `srcImage` is a compressed image, or a single-plane, “`_422`” image format, `extent.width` must be a multiple of the compressed texel block width or (`extent.width` + `srcOffset.x`) must equal the source image subresource width

- If the calling command’s `srcImage` is a compressed image, or a single-plane, “`_422`” image format, `extent.height` must be a multiple of the compressed texel block height or (`extent.height` + `srcOffset.y`) must equal the source image subresource height

- If the calling command’s `srcImage` is a compressed image, or a single-plane, “`_422`” image format, `extent.depth` must be a multiple of the compressed texel block depth or (`extent.depth` + `srcOffset.z`) must equal the source image subresource depth

- If the calling command’s `dstImage` is a compressed format image, or a single-plane, “`_422`” image format, all members of `dstOffset` must be a multiple of the corresponding dimensions of the compressed texel block

- If the calling command’s `dstImage` is a compressed format image, or a single-plane, “`_422`” image format, `extent.width` must be a multiple of the compressed texel block width or (`extent.width` + `dstOffset.x`) must equal the destination image subresource width

- If the calling command’s `dstImage` is a compressed format image, or a single-plane, “`_422`” image format, `extent.height` must be a multiple of the compressed texel block height or (`extent.height` + `dstOffset.y`) must equal the destination image subresource height

- If the calling command’s `dstImage` is a compressed format image, or a single-plane, “`_422`” image format, `extent.depth` must be a multiple of the compressed texel block depth or (`extent.depth` + `dstOffset.z`) must equal the destination image subresource depth

Valid Usage (Implicit)

- `srcSubresource` must be a valid VkImageSubresourceLayers structure

- `dstSubresource` must be a valid VkImageSubresourceLayers structure

The `VkImageSubresourceLayers` structure is defined as:

    typedef struct VkImageSubresourceLayers {
        VkImageAspectFlags    aspectMask;
        uint32_t              mipLevel;
        uint32_t              baseArrayLayer;
        uint32_t              layerCount;
    } VkImageSubresourceLayers;

- `aspectMask` is a combination of VkImageAspectFlagBits, selecting the color, depth and/or stencil aspects to be copied.

- `mipLevel` is the mipmap level to copy from.

- `baseArrayLayer` and `layerCount` are the starting layer and number of layers to copy.

Valid Usage

- If `aspectMask` contains `VK_IMAGE_ASPECT_COLOR_BIT`, it must not contain either of `VK_IMAGE_ASPECT_DEPTH_BIT` or `VK_IMAGE_ASPECT_STENCIL_BIT`

- `aspectMask` must not contain `VK_IMAGE_ASPECT_METADATA_BIT`

- `aspectMask` must not include `VK_IMAGE_ASPECT_MEMORY_PLANE_i_BIT_EXT` for any index `i`.

- `layerCount` must be greater than 0

Valid Usage (Implicit)

- `aspectMask` must be a valid combination of VkImageAspectFlagBits values

- `aspectMask` must not be `0`

### 19.4. Copying Data Between Buffers and Images

To copy data from a buffer object to an image object, call:

    void vkCmdCopyBufferToImage(
        VkCommandBuffer                             commandBuffer,
        VkBuffer                                    srcBuffer,
        VkImage                                     dstImage,
        VkImageLayout                               dstImageLayout,
        uint32_t                                    regionCount,
        const VkBufferImageCopy*                    pRegions);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `srcBuffer` is the source buffer.

- `dstImage` is the destination image.

- `dstImageLayout` is the layout of the destination image subresources for the copy.

- `regionCount` is the number of regions to copy.

- `pRegions` is a pointer to an array of VkBufferImageCopy structures specifying the regions to copy.

Each region in `pRegions` is copied from the specified region of the source buffer to the specified region of the destination image.

If the format of `dstImage` is a multi-planar image format), regions of each plane to be a target of a copy must be specified separately using the `pRegions` member of the VkBufferImageCopy structure. In this case, the `aspectMask` of `imageSubresource` must be `VK_IMAGE_ASPECT_PLANE_0_BIT`, `VK_IMAGE_ASPECT_PLANE_1_BIT`, or `VK_IMAGE_ASPECT_PLANE_2_BIT`. For the purposes of `vkCmdCopyBufferToImage`, each plane of a multi-planar image is treated as having the format listed in Compatible formats of planes of multi-planar formats for the plane identified by the `aspectMask` of the corresponding subresource. This applies both to VkFormat and to coordinates used in the copy, which correspond to texels in the plane rather than how these texels map to coordinates in the image as a whole.

Valid Usage

- `srcBuffer` must be large enough to contain all buffer locations that are accessed according to Buffer and Image Addressing, for each element of `pRegions`

- The image region specified by each element of `pRegions` must be a region that is contained within `dstImage` if the `dstImage`’s VkFormat is not a multi-planar format, and must be a region that is contained within the plane being copied to if the `dstImage`’s VkFormat is a multi-planar format

- The union of all source regions, and the union of all destination regions, specified by the elements of `pRegions`, must not overlap in memory

- `srcBuffer` must have been created with `VK_BUFFER_USAGE_TRANSFER_SRC_BIT` usage flag

- The format features of `dstImage` must contain `VK_FORMAT_FEATURE_TRANSFER_DST_BIT`.

- If `srcBuffer` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `dstImage` must have been created with `VK_IMAGE_USAGE_TRANSFER_DST_BIT` usage flag

- If `dstImage` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `dstImage` must have a sample count equal to `VK_SAMPLE_COUNT_1_BIT`

- `dstImageLayout` must specify the layout of the image subresources of `dstImage` specified in `pRegions` at the time this command is executed on a `VkDevice`

- `dstImageLayout` must be `VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL`, `VK_IMAGE_LAYOUT_GENERAL`, or `VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR`

- If `commandBuffer` is an unprotected command buffer, then `srcBuffer` must not be a protected buffer

- If `commandBuffer` is an unprotected command buffer, then `dstImage` must not be a protected image

- If `commandBuffer` is a protected command buffer, then `dstImage` must not be an unprotected image

- The `imageSubresource.mipLevel` member of each element of `pRegions` must be less than the `mipLevels` specified in VkImageCreateInfo when `dstImage` was created

- The `imageSubresource.baseArrayLayer` + `imageSubresource.layerCount` of each element of `pRegions` must be less than or equal to the `arrayLayers` specified in VkImageCreateInfo when `dstImage` was created

- The `imageOffset` and `imageExtent` members of each element of `pRegions` must respect the image transfer granularity requirements of `commandBuffer`’s command pool’s queue family, as described in VkQueueFamilyProperties

- `dstImage` must not have been created with `flags` containing `VK_IMAGE_CREATE_SUBSAMPLED_BIT_EXT`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `srcBuffer` must be a valid VkBuffer handle

- `dstImage` must be a valid VkImage handle

- `dstImageLayout` must be a valid VkImageLayout value

- `pRegions` must be a valid pointer to an array of `regionCount` valid VkBufferImageCopy structures

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support transfer, graphics, or compute operations

- This command must only be called outside of a render pass instance

- `regionCount` must be greater than `0`

- Each of `commandBuffer`, `dstImage`, and `srcBuffer` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Transfer Graphics Compute | Transfer

To copy data from an image object to a buffer object, call:

    void vkCmdCopyImageToBuffer(
        VkCommandBuffer                             commandBuffer,
        VkImage                                     srcImage,
        VkImageLayout                               srcImageLayout,
        VkBuffer                                    dstBuffer,
        uint32_t                                    regionCount,
        const VkBufferImageCopy*                    pRegions);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `srcImage` is the source image.

- `srcImageLayout` is the layout of the source image subresources for the copy.

- `dstBuffer` is the destination buffer.

- `regionCount` is the number of regions to copy.

- `pRegions` is a pointer to an array of VkBufferImageCopy structures specifying the regions to copy.

Each region in `pRegions` is copied from the specified region of the source image to the specified region of the destination buffer.

If the VkFormat of `srcImage` is a multi-planar image format, regions of each plane to be a source of a copy must be specified separately using the `pRegions` member of the VkBufferImageCopy structure. In this case, the `aspectMask` of `imageSubresource` must be `VK_IMAGE_ASPECT_PLANE_0_BIT`, `VK_IMAGE_ASPECT_PLANE_1_BIT`, or `VK_IMAGE_ASPECT_PLANE_2_BIT`. For the purposes of `vkCmdCopyBufferToImage`, each plane of a multi-planar image is treated as having the format listed in Compatible formats of planes of multi-planar formats for the plane identified by the `aspectMask` of the corresponding subresource. This applies both to VkFormat and to coordinates used in the copy, which correspond to texels in the plane rather than how these texels map to coordinates in the image as a whole.

Valid Usage

- The image region specified by each element of `pRegions` must be a region that is contained within `srcImage` if the `srcImage`’s VkFormat is not a multi-planar format, and must be a region that is contained within the plane being copied if the `srcImage`’s VkFormat is a multi-planar format

- `dstBuffer` must be large enough to contain all buffer locations that are accessed according to Buffer and Image Addressing, for each element of `pRegions`

- The union of all source regions, and the union of all destination regions, specified by the elements of `pRegions`, must not overlap in memory

- The format features of `srcImage` must contain `VK_FORMAT_FEATURE_TRANSFER_SRC_BIT`.

- `srcImage` must have been created with `VK_IMAGE_USAGE_TRANSFER_SRC_BIT` usage flag

- If `srcImage` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `srcImage` must have a sample count equal to `VK_SAMPLE_COUNT_1_BIT`

- `srcImageLayout` must specify the layout of the image subresources of `srcImage` specified in `pRegions` at the time this command is executed on a `VkDevice`

- `srcImageLayout` must be `VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR`, `VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL` or `VK_IMAGE_LAYOUT_GENERAL`

- `dstBuffer` must have been created with `VK_BUFFER_USAGE_TRANSFER_DST_BIT` usage flag

- If `dstBuffer` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- If `commandBuffer` is an unprotected command buffer, then `srcImage` must not be a protected image

- If `commandBuffer` is an unprotected command buffer, then `dstBuffer` must not be a protected buffer

- If `commandBuffer` is a protected command buffer, then `dstBuffer` must not be an unprotected buffer

- The `imageSubresource.mipLevel` member of each element of `pRegions` must be less than the `mipLevels` specified in VkImageCreateInfo when `srcImage` was created

- The `imageSubresource.baseArrayLayer` + `imageSubresource.layerCount` of each element of `pRegions` must be less than or equal to the `arrayLayers` specified in VkImageCreateInfo when `srcImage` was created

- The `imageOffset` and `imageExtent` members of each element of `pRegions` must respect the image transfer granularity requirements of `commandBuffer`’s command pool’s queue family, as described in VkQueueFamilyProperties

- `srcImage` must not have been created with `flags` containing `VK_IMAGE_CREATE_SUBSAMPLED_BIT_EXT`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `srcImage` must be a valid VkImage handle

- `srcImageLayout` must be a valid VkImageLayout value

- `dstBuffer` must be a valid VkBuffer handle

- `pRegions` must be a valid pointer to an array of `regionCount` valid VkBufferImageCopy structures

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support transfer, graphics, or compute operations

- This command must only be called outside of a render pass instance

- `regionCount` must be greater than `0`

- Each of `commandBuffer`, `dstBuffer`, and `srcImage` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Transfer Graphics Compute | Transfer

For both vkCmdCopyBufferToImage and vkCmdCopyImageToBuffer, each element of `pRegions` is a structure defined as:

    typedef struct VkBufferImageCopy {
        VkDeviceSize                bufferOffset;
        uint32_t                    bufferRowLength;
        uint32_t                    bufferImageHeight;
        VkImageSubresourceLayers    imageSubresource;
        VkOffset3D                  imageOffset;
        VkExtent3D                  imageExtent;
    } VkBufferImageCopy;

- `bufferOffset` is the offset in bytes from the start of the buffer object where the image data is copied from or to.

- `bufferRowLength` and `bufferImageHeight` specify in texels a subregion of a larger two- or three-dimensional image in buffer memory, and control the addressing calculations. If either of these values is zero, that aspect of the buffer memory is considered to be tightly packed according to the `imageExtent`.

- `imageSubresource` is a VkImageSubresourceLayers used to specify the specific image subresources of the image used for the source or destination image data.

- `imageOffset` selects the initial `x`, `y`, `z` offsets in texels of the sub-region of the source or destination image data.

- `imageExtent` is the size in texels of the image to copy in `width`, `height` and `depth`.

When copying to or from a depth or stencil aspect, the data in buffer memory uses a layout that is a (mostly) tightly packed representation of the depth or stencil data. Specifically:

- data copied to or from the stencil aspect of any depth/stencil format is tightly packed with one `VK_FORMAT_S8_UINT` value per texel.

- data copied to or from the depth aspect of a `VK_FORMAT_D16_UNORM` or `VK_FORMAT_D16_UNORM_S8_UINT` format is tightly packed with one `VK_FORMAT_D16_UNORM` value per texel.

- data copied to or from the depth aspect of a `VK_FORMAT_D32_SFLOAT` or `VK_FORMAT_D32_SFLOAT_S8_UINT` format is tightly packed with one `VK_FORMAT_D32_SFLOAT` value per texel.

- data copied to or from the depth aspect of a `VK_FORMAT_X8_D24_UNORM_PACK32` or `VK_FORMAT_D24_UNORM_S8_UINT` format is packed with one 32-bit word per texel with the D24 value in the LSBs of the word, and undefined values in the eight MSBs.

| Note To copy both the depth and stencil aspects of a depth/stencil format, two entries in `pRegions` can be used, where one specifies the depth aspect in `imageSubresource`, and the other specifies the stencil aspect.

Because depth or stencil aspect buffer to image copies may require format conversions on some implementations, they are not supported on queues that do not support graphics.

When copying to a depth aspect, and the `VK_EXT_depth_range_unrestricted` extension is not enabled, the data in buffer memory must be in the range [0,1], or the resulting values are undefined.

Copies are done layer by layer starting with image layer `baseArrayLayer` member of `imageSubresource`. `layerCount` layers are copied from the source image or to the destination image.

Valid Usage

- If the calling command’s `VkImage` parameter’s format is not a depth/stencil format or a multi-planar format, then `bufferOffset` must be a multiple of the format’s texel block size.

- If the calling command’s `VkImage` parameter’s format is a multi-planar format, then `bufferOffset` must be a multiple of the element size of the compatible format for the format and the `aspectMask` of the `imageSubresource` as defined in Compatible formats of planes of multi-planar formats

- `bufferOffset` must be a multiple of `4`

- `bufferRowLength` must be `0`, or greater than or equal to the `width` member of `imageExtent`

- `bufferImageHeight` must be `0`, or greater than or equal to the `height` member of `imageExtent`

- `imageOffset.x` and (`imageExtent.width` + `imageOffset.x`) must both be greater than or equal to `0` and less than or equal to the image subresource width where this refers to the width of the plane of the image involved in the copy in the case of a multi-planar format

- `imageOffset.y` and (imageExtent.height + `imageOffset.y`) must both be greater than or equal to `0` and less than or equal to the image subresource height where this refers to the height of the plane of the image involved in the copy in the case of a multi-planar format

- If the calling command’s `srcImage` (vkCmdCopyImageToBuffer) or `dstImage` (vkCmdCopyBufferToImage) is of type `VK_IMAGE_TYPE_1D`, then `imageOffset.y` must be `0` and `imageExtent.height` must be `1`.

- `imageOffset.z` and (imageExtent.depth + `imageOffset.z`) must both be greater than or equal to `0` and less than or equal to the image subresource depth

- If the calling command’s `srcImage` (vkCmdCopyImageToBuffer) or `dstImage` (vkCmdCopyBufferToImage) is of type `VK_IMAGE_TYPE_1D` or `VK_IMAGE_TYPE_2D`, then `imageOffset.z` must be `0` and `imageExtent.depth` must be `1`

- If the calling command’s `VkImage` parameter is a compressed image, or a single-plane, “`_422`” image format, `bufferRowLength` must be a multiple of the compressed texel block width

- If the calling command’s `VkImage` parameter is a compressed image, or a single-plane, “`_422`” image format, `bufferImageHeight` must be a multiple of the compressed texel block height

- If the calling command’s `VkImage` parameter is a compressed image, or a single-plane, “`_422`” image format, all members of `imageOffset` must be a multiple of the corresponding dimensions of the compressed texel block

- If the calling command’s `VkImage` parameter is a compressed image, or a single-plane, “`_422`” image format, `bufferOffset` must be a multiple of the compressed texel block size in bytes

- If the calling command’s `VkImage` parameter is a compressed image, or a single-plane, “`_422`” image format, `imageExtent.width` must be a multiple of the compressed texel block width or (`imageExtent.width` + `imageOffset.x`) must equal the image subresource width

- If the calling command’s `VkImage` parameter is a compressed image, or a single-plane, “`_422`” image format, `imageExtent.height` must be a multiple of the compressed texel block height or (`imageExtent.height` + `imageOffset.y`) must equal the image subresource height

- If the calling command’s `VkImage` parameter is a compressed image, or a single-plane, “`_422`” image format, `imageExtent.depth` must be a multiple of the compressed texel block depth or (`imageExtent.depth` + `imageOffset.z`) must equal the image subresource depth

- The `aspectMask` member of `imageSubresource` must specify aspects present in the calling command’s `VkImage` parameter

- If the calling command’s `VkImage` parameter’s format is a multi-planar format, then the `aspectMask` member of `imageSubresource` must be `VK_IMAGE_ASPECT_PLANE_0_BIT`, `VK_IMAGE_ASPECT_PLANE_1_BIT`, or `VK_IMAGE_ASPECT_PLANE_2_BIT` (with `VK_IMAGE_ASPECT_PLANE_2_BIT` valid only for image formats with three planes)

- The `aspectMask` member of `imageSubresource` must only have a single bit set

- If the calling command’s `VkImage` parameter is of VkImageType `VK_IMAGE_TYPE_3D`, the `baseArrayLayer` and `layerCount` members of `imageSubresource` must be `0` and `1`, respectively

Valid Usage (Implicit)

- `imageSubresource` must be a valid VkImageSubresourceLayers structure

#### 19.4.1. Buffer and Image Addressing

Pseudocode for image/buffer addressing of uncompressed formats is:

    rowLength = region->bufferRowLength;
    if (rowLength == 0)
        rowLength = region->imageExtent.width;

    imageHeight = region->bufferImageHeight;
    if (imageHeight == 0)
        imageHeight = region->imageExtent.height;

    texelBlockSize = <texel block size of the format of the src/dstImage>;

    address of (x,y,z) = region->bufferOffset + (((z * imageHeight) + y) * rowLength + x) * texelBlockSize;

    where x,y,z range from (0,0,0) to region->imageExtent.{width,height,depth}.

Note that `imageOffset` does not affect addressing calculations for buffer memory. Instead, `bufferOffset` can be used to select the starting address in buffer memory.

For block-compressed formats, all parameters are still specified in texels rather than compressed texel blocks, but the addressing math operates on whole compressed texel blocks. Pseudocode for compressed copy addressing is:

    rowLength = region->bufferRowLength;
    if (rowLength == 0)
        rowLength = region->imageExtent.width;

    imageHeight = region->bufferImageHeight;
    if (imageHeight == 0)
        imageHeight = region->imageExtent.height;

    compressedTexelBlockSizeInBytes = <compressed texel block size taken from the src/dstImage>;
    rowLength /= compressedTexelBlockWidth;
    imageHeight /= compressedTexelBlockHeight;

    address of (x,y,z) = region->bufferOffset + (((z * imageHeight) + y) * rowLength + x) * compressedTexelBlockSizeInBytes;

    where x,y,z range from (0,0,0) to region->imageExtent.{width/compressedTexelBlockWidth,height/compressedTexelBlockHeight,depth/compressedTexelBlockDepth}.

Copying to or from block-compressed images is typically done in multiples of the compressed texel block size. For this reason the `imageExtent` must be a multiple of the compressed texel block dimension. There is one exception to this rule which is required to handle compressed images created with dimensions that are not a multiple of the compressed texel block dimensions:

- If `imageExtent.width` is not a multiple of the compressed texel block width, then (`imageExtent.width` + `imageOffset.x`) must equal the image subresource width.

- If `imageExtent.height` is not a multiple of the compressed texel block height, then (`imageExtent.height` + `imageOffset.y`) must equal the image subresource height.

- If `imageExtent.depth` is not a multiple of the compressed texel block depth, then (`imageExtent.depth` + `imageOffset.z`) must equal the image subresource depth.

This allows the last compressed texel block of the image in each non-multiple dimension to be included as a source or destination of the copy.

### 19.5. Image Copies with Scaling

To copy regions of a source image into a destination image, potentially performing format conversion, arbitrary scaling, and filtering, call:

    void vkCmdBlitImage(
        VkCommandBuffer                             commandBuffer,
        VkImage                                     srcImage,
        VkImageLayout                               srcImageLayout,
        VkImage                                     dstImage,
        VkImageLayout                               dstImageLayout,
        uint32_t                                    regionCount,
        const VkImageBlit*                          pRegions,
        VkFilter                                    filter);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `srcImage` is the source image.

- `srcImageLayout` is the layout of the source image subresources for the blit.

- `dstImage` is the destination image.

- `dstImageLayout` is the layout of the destination image subresources for the blit.

- `regionCount` is the number of regions to blit.

- `pRegions` is a pointer to an array of VkImageBlit structures specifying the regions to blit.

- `filter` is a VkFilter specifying the filter to apply if the blits require scaling.

`vkCmdBlitImage` must not be used for multisampled source or destination images. Use vkCmdResolveImage for this purpose.

As the sizes of the source and destination extents can differ in any dimension, texels in the source extent are scaled and filtered to the destination extent. Scaling occurs via the following operations:

- For each destination texel, the integer coordinate of that texel is converted to an unnormalized texture coordinate, using the effective inverse of the equations described in unnormalized to integer conversion:

    ubase = i + ½

    vbase = j + ½

    wbase = k + ½

- These base coordinates are then offset by the first destination offset:

    uoffset = ubase - xdst0

    voffset = vbase - ydst0

    woffset = wbase - zdst0

    aoffset = a - `baseArrayCount`dst

- The scale is determined from the source and destination regions, and applied to the offset coordinates:

    scale_u = (xsrc1 - xsrc0) / (xdst1 - xdst0)

    scale_v = (ysrc1 - ysrc0) / (ydst1 - ydst0)

    scale_w = (zsrc1 - zsrc0) / (zdst1 - zdst0)

    uscaled = uoffset * scaleu

    vscaled = voffset * scalev

    wscaled = woffset * scalew

- Finally the source offset is added to the scaled coordinates, to determine the final unnormalized coordinates used to sample from `srcImage`:

    u = uscaled + xsrc0

    v = vscaled + ysrc0

    w = wscaled + zsrc0

    q = `mipLevel`

    a = aoffset + `baseArrayCount`src

These coordinates are used to sample from the source image, as described in Image Operations chapter, with the filter mode equal to that of `filter`, a mipmap mode of `VK_SAMPLER_MIPMAP_MODE_NEAREST` and an address mode of `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`. Implementations must clamp at the edge of the source image, and may additionally clamp to the edge of the source region.

| Note Due to allowable rounding errors in the generation of the source texture coordinates, it is not always possible to guarantee exactly which source texels will be sampled for a given blit. As rounding errors are implementation dependent, the exact results of a blitting operation are also implementation dependent.

Blits are done layer by layer starting with the `baseArrayLayer` member of `srcSubresource` for the source and `dstSubresource` for the destination. `layerCount` layers are blitted to the destination image.

3D textures are blitted slice by slice. Slices in the source region bounded by `srcOffsets`[0].z and `srcOffsets`[1].z are copied to slices in the destination region bounded by `dstOffsets`[0].z and `dstOffsets`[1].z. For each destination slice, a source z coordinate is linearly interpolated between `srcOffsets`[0].z and `srcOffsets`[1].z. If the `filter` parameter is `VK_FILTER_LINEAR` then the value sampled from the source image is taken by doing linear filtering using the interpolated z coordinate. If `filter` parameter is `VK_FILTER_NEAREST` then the value sampled from the source image is taken from the single nearest slice, with an implementation-dependent arithmetic rounding mode.

The following filtering and conversion rules apply:

- Integer formats can only be converted to other integer formats with the same signedness.

- No format conversion is supported between depth/stencil images. The formats must match.

- Format conversions on unorm, snorm, unscaled and packed float formats of the copied aspect of the image are performed by first converting the pixels to float values.

- For sRGB source formats, nonlinear RGB values are converted to linear representation prior to filtering.

- After filtering, the float values are first clamped and then cast to the destination image format. In case of sRGB destination format, linear RGB values are converted to nonlinear representation before writing the pixel to the image.

Signed and unsigned integers are converted by first clamping to the representable range of the destination format, then casting the value.

Valid Usage

- The source region specified by each element of `pRegions` must be a region that is contained within `srcImage`

- The destination region specified by each element of `pRegions` must be a region that is contained within `dstImage`

- The union of all destination regions, specified by the elements of `pRegions`, must not overlap in memory with any texel that may be sampled during the blit operation

- The format features of `srcImage` must contain `VK_FORMAT_FEATURE_BLIT_SRC_BIT`.

- `srcImage` must not use a format listed in Formats requiring sampler Y′CBCR conversion for `VK_IMAGE_ASPECT_COLOR_BIT` image views

- `srcImage` must have been created with `VK_IMAGE_USAGE_TRANSFER_SRC_BIT` usage flag

- If `srcImage` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `srcImageLayout` must specify the layout of the image subresources of `srcImage` specified in `pRegions` at the time this command is executed on a `VkDevice`

- `srcImageLayout` must be `VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR`, `VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL` or `VK_IMAGE_LAYOUT_GENERAL`

- The format features of `dstImage` must contain `VK_FORMAT_FEATURE_BLIT_DST_BIT`.

- `dstImage` must not use a format listed in Formats requiring sampler Y′CBCR conversion for `VK_IMAGE_ASPECT_COLOR_BIT` image views

- `dstImage` must have been created with `VK_IMAGE_USAGE_TRANSFER_DST_BIT` usage flag

- If `dstImage` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `dstImageLayout` must specify the layout of the image subresources of `dstImage` specified in `pRegions` at the time this command is executed on a `VkDevice`

- `dstImageLayout` must be `VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR`, `VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL` or `VK_IMAGE_LAYOUT_GENERAL`

- The sample count of `srcImage` and `dstImage` must both be equal to `VK_SAMPLE_COUNT_1_BIT`

- If either of `srcImage` or `dstImage` was created with a signed integer VkFormat, the other must also have been created with a signed integer VkFormat

- If either of `srcImage` or `dstImage` was created with an unsigned integer VkFormat, the other must also have been created with an unsigned integer VkFormat

- If either of `srcImage` or `dstImage` was created with a depth/stencil format, the other must have exactly the same format

- If `srcImage` was created with a depth/stencil format, `filter` must be `VK_FILTER_NEAREST`

- `srcImage` must have been created with a `samples` value of `VK_SAMPLE_COUNT_1_BIT`

- `dstImage` must have been created with a `samples` value of `VK_SAMPLE_COUNT_1_BIT`

- If `filter` is `VK_FILTER_LINEAR`, then the format features of `srcImage` must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT`.

- If `filter` is `VK_FILTER_CUBIC_EXT`, then the format features of `srcImage` must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_EXT`.

- If `filter` is `VK_FILTER_CUBIC_EXT`, `srcImage` must have a VkImageType of `VK_IMAGE_TYPE_2D`

- If `commandBuffer` is an unprotected command buffer, then `srcImage` must not be a protected image

- If `commandBuffer` is an unprotected command buffer, then `dstImage` must not be a protected image

- If `commandBuffer` is a protected command buffer, then `dstImage` must not be an unprotected image

- The `srcSubresource.mipLevel` member of each element of `pRegions` must be less than the `mipLevels` specified in VkImageCreateInfo when `srcImage` was created

- The `dstSubresource.mipLevel` member of each element of `pRegions` must be less than the `mipLevels` specified in VkImageCreateInfo when `dstImage` was created

- The `srcSubresource.baseArrayLayer` + `srcSubresource.layerCount` of each element of `pRegions` must be less than or equal to the `arrayLayers` specified in VkImageCreateInfo when `srcImage` was created

- The `dstSubresource.baseArrayLayer` + `dstSubresource.layerCount` of each element of `pRegions` must be less than or equal to the `arrayLayers` specified in VkImageCreateInfo when `dstImage` was created

- `dstImage` and `srcImage` must not have been created with `flags` containing `VK_IMAGE_CREATE_SUBSAMPLED_BIT_EXT`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `srcImage` must be a valid VkImage handle

- `srcImageLayout` must be a valid VkImageLayout value

- `dstImage` must be a valid VkImage handle

- `dstImageLayout` must be a valid VkImageLayout value

- `pRegions` must be a valid pointer to an array of `regionCount` valid VkImageBlit structures

- `filter` must be a valid VkFilter value

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- This command must only be called outside of a render pass instance

- `regionCount` must be greater than `0`

- Each of `commandBuffer`, `dstImage`, and `srcImage` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Graphics | Transfer

The `VkImageBlit` structure is defined as:

    typedef struct VkImageBlit {
        VkImageSubresourceLayers    srcSubresource;
        VkOffset3D                  srcOffsets[2];
        VkImageSubresourceLayers    dstSubresource;
        VkOffset3D                  dstOffsets[2];
    } VkImageBlit;

- `srcSubresource` is the subresource to blit from.

- `srcOffsets` is a pointer to an array of two VkOffset3D structures specifying the bounds of the source region within `srcSubresource`.

- `dstSubresource` is the subresource to blit into.

- `dstOffsets` is a pointer to an array of two VkOffset3D structures specifying the bounds of the destination region within `dstSubresource`.

For each element of the `pRegions` array, a blit operation is performed the specified source and destination regions.

Valid Usage

- The `aspectMask` member of `srcSubresource` and `dstSubresource` must match

- The `layerCount` member of `srcSubresource` and `dstSubresource` must match

- If either of the calling command’s `srcImage` or `dstImage` parameters are of VkImageType `VK_IMAGE_TYPE_3D`, the `baseArrayLayer` and `layerCount` members of both `srcSubresource` and `dstSubresource` must be `0` and `1`, respectively

- The `aspectMask` member of `srcSubresource` must specify aspects present in the calling command’s `srcImage`

- The `aspectMask` member of `dstSubresource` must specify aspects present in the calling command’s `dstImage`

- `srcOffset`[0].x and `srcOffset`[1].x must both be greater than or equal to `0` and less than or equal to the source image subresource width

- `srcOffset`[0].y and `srcOffset`[1].y must both be greater than or equal to `0` and less than or equal to the source image subresource height

- If the calling command’s `srcImage` is of type `VK_IMAGE_TYPE_1D`, then `srcOffset`[0].y must be `0` and `srcOffset`[1].y must be `1`.

- `srcOffset`[0].z and `srcOffset`[1].z must both be greater than or equal to `0` and less than or equal to the source image subresource depth

- If the calling command’s `srcImage` is of type `VK_IMAGE_TYPE_1D` or `VK_IMAGE_TYPE_2D`, then `srcOffset`[0].z must be `0` and `srcOffset`[1].z must be `1`.

- `dstOffset`[0].x and `dstOffset`[1].x must both be greater than or equal to `0` and less than or equal to the destination image subresource width

- `dstOffset`[0].y and `dstOffset`[1].y must both be greater than or equal to `0` and less than or equal to the destination image subresource height

- If the calling command’s `dstImage` is of type `VK_IMAGE_TYPE_1D`, then `dstOffset`[0].y must be `0` and `dstOffset`[1].y must be `1`.

- `dstOffset`[0].z and `dstOffset`[1].z must both be greater than or equal to `0` and less than or equal to the destination image subresource depth

- If the calling command’s `dstImage` is of type `VK_IMAGE_TYPE_1D` or `VK_IMAGE_TYPE_2D`, then `dstOffset`[0].z must be `0` and `dstOffset`[1].z must be `1`.

Valid Usage (Implicit)

- `srcSubresource` must be a valid VkImageSubresourceLayers structure

- `dstSubresource` must be a valid VkImageSubresourceLayers structure

### 19.6. Resolving Multisample Images

To resolve a multisample image to a non-multisample image, call:

    void vkCmdResolveImage(
        VkCommandBuffer                             commandBuffer,
        VkImage                                     srcImage,
        VkImageLayout                               srcImageLayout,
        VkImage                                     dstImage,
        VkImageLayout                               dstImageLayout,
        uint32_t                                    regionCount,
        const VkImageResolve*                       pRegions);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `srcImage` is the source image.

- `srcImageLayout` is the layout of the source image subresources for the resolve.

- `dstImage` is the destination image.

- `dstImageLayout` is the layout of the destination image subresources for the resolve.

- `regionCount` is the number of regions to resolve.

- `pRegions` is a pointer to an array of VkImageResolve structures specifying the regions to resolve.

During the resolve the samples corresponding to each pixel location in the source are converted to a single sample before being written to the destination. If the source formats are floating-point or normalized types, the sample values for each pixel are resolved in an implementation-dependent manner. If the source formats are integer types, a single sample’s value is selected for each pixel.

`srcOffset` and `dstOffset` select the initial `x`, `y`, and `z` offsets in texels of the sub-regions of the source and destination image data. `extent` is the size in texels of the source image to resolve in `width`, `height` and `depth`.

Resolves are done layer by layer starting with `baseArrayLayer` member of `srcSubresource` for the source and `dstSubresource` for the destination. `layerCount` layers are resolved to the destination image.

Valid Usage

- The source region specified by each element of `pRegions` must be a region that is contained within `srcImage`

- The destination region specified by each element of `pRegions` must be a region that is contained within `dstImage`

- The union of all source regions, and the union of all destination regions, specified by the elements of `pRegions`, must not overlap in memory

- If `srcImage` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `srcImage` must have a sample count equal to any valid sample count value other than `VK_SAMPLE_COUNT_1_BIT`

- If `dstImage` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `dstImage` must have a sample count equal to `VK_SAMPLE_COUNT_1_BIT`

- `srcImageLayout` must specify the layout of the image subresources of `srcImage` specified in `pRegions` at the time this command is executed on a `VkDevice`

- `srcImageLayout` must be `VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR`, `VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL` or `VK_IMAGE_LAYOUT_GENERAL`

- `dstImageLayout` must specify the layout of the image subresources of `dstImage` specified in `pRegions` at the time this command is executed on a `VkDevice`

- `dstImageLayout` must be `VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR`, `VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL` or `VK_IMAGE_LAYOUT_GENERAL`

- The format features of `dstImage` must contain `VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT`.

- `srcImage` and `dstImage` must have been created with the same image format

- If `commandBuffer` is an unprotected command buffer, then `srcImage` must not be a protected image

- If `commandBuffer` is an unprotected command buffer, then `dstImage` must not be a protected image

- If `commandBuffer` is a protected command buffer, then `dstImage` must not be an unprotected image

- The `srcSubresource.mipLevel` member of each element of `pRegions` must be less than the `mipLevels` specified in VkImageCreateInfo when `srcImage` was created

- The `dstSubresource.mipLevel` member of each element of `pRegions` must be less than the `mipLevels` specified in VkImageCreateInfo when `dstImage` was created

- The `srcSubresource.baseArrayLayer` + `srcSubresource.layerCount` of each element of `pRegions` must be less than or equal to the `arrayLayers` specified in VkImageCreateInfo when `srcImage` was created

- The `dstSubresource.baseArrayLayer` + `dstSubresource.layerCount` of each element of `pRegions` must be less than or equal to the `arrayLayers` specified in VkImageCreateInfo when `dstImage` was created

- `dstImage` and `srcImage` must not have been created with `flags` containing `VK_IMAGE_CREATE_SUBSAMPLED_BIT_EXT`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `srcImage` must be a valid VkImage handle

- `srcImageLayout` must be a valid VkImageLayout value

- `dstImage` must be a valid VkImage handle

- `dstImageLayout` must be a valid VkImageLayout value

- `pRegions` must be a valid pointer to an array of `regionCount` valid VkImageResolve structures

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- This command must only be called outside of a render pass instance

- `regionCount` must be greater than `0`

- Each of `commandBuffer`, `dstImage`, and `srcImage` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Graphics | Transfer

The `VkImageResolve` structure is defined as:

    typedef struct VkImageResolve {
        VkImageSubresourceLayers    srcSubresource;
        VkOffset3D                  srcOffset;
        VkImageSubresourceLayers    dstSubresource;
        VkOffset3D                  dstOffset;
        VkExtent3D                  extent;
    } VkImageResolve;

- `srcSubresource` and `dstSubresource` are VkImageSubresourceLayers structures specifying the image subresources of the images used for the source and destination image data, respectively. Resolve of depth/stencil images is not supported.

- `srcOffset` and `dstOffset` select the initial `x`, `y`, and `z` offsets in texels of the sub-regions of the source and destination image data.

- `extent` is the size in texels of the source image to resolve in `width`, `height` and `depth`.

Valid Usage

- The `aspectMask` member of `srcSubresource` and `dstSubresource` must only contain `VK_IMAGE_ASPECT_COLOR_BIT`

- The `layerCount` member of `srcSubresource` and `dstSubresource` must match

- If either of the calling command’s `srcImage` or `dstImage` parameters are of VkImageType `VK_IMAGE_TYPE_3D`, the `baseArrayLayer` and `layerCount` members of both `srcSubresource` and `dstSubresource` must be `0` and `1`, respectively

- `srcOffset.x` and (`extent.width` + `srcOffset.x`) must both be greater than or equal to `0` and less than or equal to the source image subresource width

- `srcOffset.y` and (`extent.height` + `srcOffset.y`) must both be greater than or equal to `0` and less than or equal to the source image subresource height

- If the calling command’s `srcImage` is of type `VK_IMAGE_TYPE_1D`, then `srcOffset.y` must be `0` and `extent.height` must be `1`.

- `srcOffset.z` and (`extent.depth` + `srcOffset.z`) must both be greater than or equal to `0` and less than or equal to the source image subresource depth

- If the calling command’s `srcImage` is of type `VK_IMAGE_TYPE_1D` or `VK_IMAGE_TYPE_2D`, then `srcOffset.z` must be `0` and `extent.depth` must be `1`.

- `dstOffset.x` and (`extent.width` + `dstOffset.x`) must both be greater than or equal to `0` and less than or equal to the destination image subresource width

- `dstOffset.y` and (`extent.height` + `dstOffset.y`) must both be greater than or equal to `0` and less than or equal to the destination image subresource height

- If the calling command’s `dstImage` is of type `VK_IMAGE_TYPE_1D`, then `dstOffset.y` must be `0` and `extent.height` must be `1`.

- `dstOffset.z` and (`extent.depth` + `dstOffset.z`) must both be greater than or equal to `0` and less than or equal to the destination image subresource depth

- If the calling command’s `dstImage` is of type `VK_IMAGE_TYPE_1D` or `VK_IMAGE_TYPE_2D`, then `dstOffset.z` must be `0` and `extent.depth` must be `1`.

Valid Usage (Implicit)

- `srcSubresource` must be a valid VkImageSubresourceLayers structure

- `dstSubresource` must be a valid VkImageSubresourceLayers structure

### 19.7. Buffer Markers

To write a 32-bit marker value into a buffer as a pipelined operation, call:

    void vkCmdWriteBufferMarkerAMD(
        VkCommandBuffer                             commandBuffer,
        VkPipelineStageFlagBits                     pipelineStage,
        VkBuffer                                    dstBuffer,
        VkDeviceSize                                dstOffset,
        uint32_t                                    marker);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `pipelineStage` is one of the VkPipelineStageFlagBits values, specifying the pipeline stage whose completion triggers the marker write.

- `dstBuffer` is the buffer where the marker will be written to.

- `dstOffset` is the byte offset into the buffer where the marker will be written to.

- `marker` is the 32-bit value of the marker.

The command will write the 32-bit marker value into the buffer only after all preceding commands have finished executing up to at least the specified pipeline stage. This includes the completion of other preceding `vkCmdWriteBufferMarkerAMD` commands so long as their specified pipeline stages occur either at the same time or earlier than this command’s specified `pipelineStage`.

While consecutive buffer marker writes with the same `pipelineStage` parameter are implicitly complete in submission order, memory and execution dependencies between buffer marker writes and other operations must still be explicitly ordered using synchronization commands. The access scope for buffer marker writes falls under the `VK_ACCESS_TRANSFER_WRITE_BIT`, and the pipeline stages for identifying the synchronization scope must include both `pipelineStage` and `VK_PIPELINE_STAGE_TRANSFER_BIT`.

| Note Similar to `vkCmdWriteTimestamp`, if an implementation is unable to write a marker at any specific pipeline stage, it may instead do so at any logically later stage.

| Note Implementations may only support a limited number of pipelined marker write operations in flight at a given time, thus excessive number of marker write operations may degrade command execution performance.

Valid Usage

- `dstOffset` must be less than or equal to the size of `dstBuffer` minus `4`.

- `dstBuffer` must have been created with `VK_BUFFER_USAGE_TRANSFER_DST_BIT` usage flag

- If `dstBuffer` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `dstOffset` must be a multiple of `4`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pipelineStage` must be a valid VkPipelineStageFlagBits value

- `dstBuffer` must be a valid VkBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support transfer, graphics, or compute operations

- Both of `commandBuffer`, and `dstBuffer` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Transfer Graphics Compute | Transfer

## 20. Drawing Commands

Drawing commands (commands with `Draw` in the name) provoke work in a graphics pipeline. Drawing commands are recorded into a command buffer and when executed by a queue, will produce work which executes according to the bound graphics pipeline. A graphics pipeline must be bound to a command buffer before any drawing commands are recorded in that command buffer.

Drawing can be achieved in two modes:

- Programmable Mesh Shading, the mesh shader assembles primitives, or

- Programmable Primitive Shading, the input primitives are assembled

as follows.

Each draw is made up of zero or more vertices and zero or more instances, which are processed by the device and result in the assembly of primitives. Primitives are assembled according to the `pInputAssemblyState` member of the `VkGraphicsPipelineCreateInfo` structure, which is of type `VkPipelineInputAssemblyStateCreateInfo`:

    typedef struct VkPipelineInputAssemblyStateCreateInfo {
        VkStructureType                            sType;
        const void*                                pNext;
        VkPipelineInputAssemblyStateCreateFlags    flags;
        VkPrimitiveTopology                        topology;
        VkBool32                                   primitiveRestartEnable;
    } VkPipelineInputAssemblyStateCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `topology` is a VkPrimitiveTopology defining the primitive topology, as described below.

- `primitiveRestartEnable` controls whether a special vertex index value is treated as restarting the assembly of primitives. This enable only applies to indexed draws (vkCmdDrawIndexed and vkCmdDrawIndexedIndirect), and the special index value is either 0xFFFFFFFF when the `indexType` parameter of `vkCmdBindIndexBuffer` is equal to `VK_INDEX_TYPE_UINT32`, 0xFF when `indexType` is equal to `VK_INDEX_TYPE_UINT8_EXT`, or 0xFFFF when `indexType` is equal to `VK_INDEX_TYPE_UINT16`. Primitive restart is not allowed for “list” topologies.

Restarting the assembly of primitives discards the most recent index values if those elements formed an incomplete primitive, and restarts the primitive assembly using the subsequent indices, but only assembling the immediately following element through the end of the originally specified elements. The primitive restart index value comparison is performed before adding the `vertexOffset` value to the index value.

Valid Usage

- If `topology` is `VK_PRIMITIVE_TOPOLOGY_POINT_LIST`, `VK_PRIMITIVE_TOPOLOGY_LINE_LIST`, `VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST`, `VK_PRIMITIVE_TOPOLOGY_LINE_LIST_WITH_ADJACENCY`, `VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST_WITH_ADJACENCY` or `VK_PRIMITIVE_TOPOLOGY_PATCH_LIST`, `primitiveRestartEnable` must be `VK_FALSE`

- If the geometry shaders feature is not enabled, `topology` must not be any of `VK_PRIMITIVE_TOPOLOGY_LINE_LIST_WITH_ADJACENCY`, `VK_PRIMITIVE_TOPOLOGY_LINE_STRIP_WITH_ADJACENCY`, `VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST_WITH_ADJACENCY` or `VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP_WITH_ADJACENCY`

- If the tessellation shaders feature is not enabled, `topology` must not be `VK_PRIMITIVE_TOPOLOGY_PATCH_LIST`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_INPUT_ASSEMBLY_STATE_CREATE_INFO`

- `pNext` must be `NULL`

- `flags` must be `0`

- `topology` must be a valid VkPrimitiveTopology value

    typedef VkFlags VkPipelineInputAssemblyStateCreateFlags;

`VkPipelineInputAssemblyStateCreateFlags` is a bitmask type for setting a mask, but is currently reserved for future use.

### 20.1. Primitive Topologies

Primitive topology determines how consecutive vertices are organized into primitives, and determines the type of primitive that is used at the beginning of the graphics pipeline. The effective topology for later stages of the pipeline is altered by tessellation or geometry shading (if either is in use) and depends on the execution modes of those shaders. In the case of mesh shading the only effective topology is defined by the execution mode of the mesh shader.

The primitive topologies defined by VkPrimitiveTopology are:

    typedef enum VkPrimitiveTopology {
        VK_PRIMITIVE_TOPOLOGY_POINT_LIST = 0,
        VK_PRIMITIVE_TOPOLOGY_LINE_LIST = 1,
        VK_PRIMITIVE_TOPOLOGY_LINE_STRIP = 2,
        VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST = 3,
        VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP = 4,
        VK_PRIMITIVE_TOPOLOGY_TRIANGLE_FAN = 5,
        VK_PRIMITIVE_TOPOLOGY_LINE_LIST_WITH_ADJACENCY = 6,
        VK_PRIMITIVE_TOPOLOGY_LINE_STRIP_WITH_ADJACENCY = 7,
        VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST_WITH_ADJACENCY = 8,
        VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP_WITH_ADJACENCY = 9,
        VK_PRIMITIVE_TOPOLOGY_PATCH_LIST = 10,
        VK_PRIMITIVE_TOPOLOGY_MAX_ENUM = 0x7FFFFFFF
    } VkPrimitiveTopology;

- `VK_PRIMITIVE_TOPOLOGY_POINT_LIST` specifies a series of separate point primitives.

- `VK_PRIMITIVE_TOPOLOGY_LINE_LIST` specifies a series of separate line primitives.

- `VK_PRIMITIVE_TOPOLOGY_LINE_STRIP` specifies a series of connected line primitives with consecutive lines sharing a vertex.

- `VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST` specifies a series of separate triangle primitives.

- `VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP` specifies a series of connected triangle primitives with consecutive triangles sharing an edge.

- `VK_PRIMITIVE_TOPOLOGY_TRIANGLE_FAN` specifies a series of connected triangle primitives with all triangles sharing a common vertex.

- `VK_PRIMITIVE_TOPOLOGY_LINE_LIST_WITH_ADJACENCY` specifies a series of separate line primitives with adjacency.

- `VK_PRIMITIVE_TOPOLOGY_LINE_STRIP_WITH_ADJACENCY` specifies a series of connected line primitives with adjacency, with consecutive primitives sharing three vertices.

- `VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST_WITH_ADJACENCY` specifies a series of separate triangle primitives with adjacency.

- `VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP_WITH_ADJACENCY` specifies connected triangle primitives with adjacency, with consecutive triangles sharing an edge.

- `VK_PRIMITIVE_TOPOLOGY_PATCH_LIST` specifies separate patch primitives.

Each primitive topology, and its construction from a list of vertices, is described in detail below with a supporting diagram, according to the following key:

| Vertex | A point in 3-dimensional space. Positions chosen within the diagrams are arbitrary and for illustration only.
| Vertex Number | Sequence position of a vertex within the provided vertex data.
| Provoking Vertex | Provoking vertex within the main primitive. The arrow points along an edge of the relevant primitive, following winding order. Used in flat shading.
| Primitive Edge | An edge connecting the points of a main primitive.
| Adjacency Edge | Points connected by these lines do not contribute to a main primitive, and are only accessible in a geometry shader.
| Winding Order | The relative order in which vertices are defined within a primitive, used in the facing determination. This ordering has no specific start or end point.

The diagrams are supported with mathematical definitions where the vertices (v) and primitives (p) are numbered starting from 0; v0 is the first vertex in the provided data and p0 is the first primitive in the set of primitives defined by the vertices and topology.

#### 20.1.1. Point Lists

When the topology is `VK_PRIMITIVE_TOPOLOGY_POINT_LIST`, each consecutive vertex defines a single point primitive, according to the equation:

  pi = {vi}

As there is only one vertex, that vertex is the provoking vertex. The number of primitives generated is equal to `vertexCount`.

#### 20.1.2. Line Lists

When the `topology` is `VK_PRIMITIVE_TOPOLOGY_LINE_LIST`, each consecutive pair of vertices defines a single line primitive, according to the equation:

  pi = {v2i, v2i+1}

The provoking vertex for pi is v2i. The number of primitives generated is equal to ⌊`vertexCount`/2⌋.

#### 20.1.3. Line Strips

When the `topology` is `VK_PRIMITIVE_TOPOLOGY_LINE_STRIP`, one line primitive is defined by each vertex and the following vertex, according to the equation:

  pi = {vi, vi+1}

The provoking vertex for pi is vi. The number of primitives generated is equal to max(0,`vertexCount`-1).

#### 20.1.4. Triangle Lists

When the `topology` is `VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST`, each consecutive set of three vertices defines a single triangle primitive, according to the equation:

  pi = {v3i, v3i+1, v3i+2}

The provoking vertex for pi is v3i. The number of primitives generated is equal to ⌊`vertexCount`/3⌋.

#### 20.1.5. Triangle Strips

When the `topology` is `VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP`, one triangle primitive is defined by each vertex and the two vertices that follow it, according to the equation:

  pi = {vi, vi+(1+i%2), vi+(2-i%2)}

The provoking vertex for pi is vi. The number of primitives generated is equal to max(0,`vertexCount`-2).

| Note The ordering of the vertices in each successive triangle is reversed, so that the winding order is consistent throughout the strip.

#### 20.1.6. Triangle Fans

When the `topology` is `VK_PRIMITIVE_TOPOLOGY_TRIANGLE_FAN`, triangle primitives are defined around a shared common vertex, according to the equation:

  pi = {vi+1, vi+2, v0}

The provoking vertex for pi is vi+1. The number of primitives generated is equal to max(0,`vertexCount`-2).

#### 20.1.7. Line Lists With Adjacency

When the `topology` is `VK_PRIMITIVE_TOPOLOGY_LINE_LIST_WITH_ADJACENCY`, each consecutive set of four vertices defines a single line primitive with adjacency, according to the equation:

  pi = {v4i, v4i+1, v4i+2,v4i+3}

A line primitive is described by the second and third vertices of the total primitive, with the remaining two vertices only accessible in a geometry shader.

The provoking vertex for pi is v4i+1. The number of primitives generated is equal to ⌊`vertexCount`/4⌋.

#### 20.1.8. Line Strips With Adjacency

When the `topology` is `VK_PRIMITIVE_TOPOLOGY_LINE_STRIP_WITH_ADJACENCY`, one line primitive with adjacency is defined by each vertex and the following vertex, according to the equation:

  pi = {vi, vi+1, vi+2, vi+3}

A line primitive is described by the second and third vertices of the total primitive, with the remaining two vertices only accessible in a geometry shader.

The provoking vertex for pi is vi+1. The number of primitives generated is equal to max(0,`vertexCount`-3).

#### 20.1.9. Triangle Lists With Adjacency

When the `topology` is `VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST_WITH_ADJACENCY`, each consecutive set of six vertices defines a single triangle primitive with adjacency, according to the equations:

  pi = {v6i, v6i+1, v6i+2, v6i+3, v6i+4, v6i+5}

A triangle primitive is described by the first, third, and fifth vertices of the total primitive, with the remaining three vertices only accessible in a geometry shader.

The provoking vertex for pi is v6i. The number of primitives generated is equal to ⌊`vertexCount`/6⌋.

#### 20.1.10. Triangle Strips With Adjacency

When the `topology` is `VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP_WITH_ADJACENCY`, one triangle primitive with adjacency is defined by each vertex and the following 5 vertices.

The number of primitives generated, n, is equal to ⌊max(0, `vertexCount` - 4)/2⌋.

If n=1, the primitive is defined as:

  p = {v0, v1, v2, v5, v4, v3}

If n>1, the total primitive consists of different vertices according to where it is in the strip:

  pi = {v2i, v2i+1, v2i+2, v2i+6, v2i+4, v2i+3} when i=0

  pi = {v2i, v2i+3, v2i+4, v2i+6, v2i+2, v2i-2} when i>0, i<n-1, and i%2=1

  pi = {v2i, v2i-2, v2i+2, v2i+6, v2i+4, v2i+3} when i>0, i<n-1, and i%2=0

  pi = {v2i, v2i+3, v2i+4, v2i+5, v2i+2, v2i-2} when i=n-1 and i%2=1

  pi = {v2i, v2i-2, v2i+2, v2i+5, v2i+4, v2i+3} when i=n-1 and i%2=0

A triangle primitive is described by the first, third, and fifth vertices of the total primitive in all cases, with the remaining three vertices only accessible in a geometry shader.

| Note The ordering of the vertices in each successive triangle is altered so that the winding order is consistent throughout the strip.

The provoking vertex for pi is always v2i.

#### 20.1.11. Patch Lists

When the `topology` is `VK_PRIMITIVE_TOPOLOGY_PATCH_LIST`, each consecutive set of m vertices defines a single patch primitive, according to the equation:

  pi = {vmi, vmi+1, …​, vmi+(m-2), vmi+(m-1)}

where m is equal to VkPipelineTessellationStateCreateInfo::`patchControlPoints`.

Patch lists are never passed to vertex post-processing, and as such no provoking vertex is defined for patch primitives. The number of primitives generated is equal to ⌊`vertexCount`/m⌋.

The vertices comprising a patch have no implied geometry, and are used as inputs to tessellation shaders and the fixed-function tessellator to generate new point, line, or triangle primitives.

### 20.2. Primitive Order

Primitives generated by drawing commands progress through the stages of the graphics pipeline in primitive order. Primitive order is initially determined in the following way:

1. Submission order determines the initial ordering

2. For indirect draw commands, the order in which accessed instances of the VkDrawIndirectCommand are stored in `buffer`, from lower indirect buffer addresses to higher addresses.

3. If a draw command includes multiple instances, the order in which instances are executed, from lower numbered instances to higher.

4. The order in which primitives are specified by a draw command:

   - For non-indexed draws, from vertices with a lower numbered `vertexIndex` to a higher numbered `vertexIndex`.

   - For indexed draws, vertices sourced from a lower index buffer addresses to higher addresses.

   - For draws using mesh shaders, the order is provided by mesh shading.

Within this order implementations further sort primitives:

5. If tessellation shading is active, by an implementation-dependent order of new primitives generated by tessellation.

6. If geometry shading is active, by the order new primitives are generated by geometry shading.

7. If the polygon mode is not `VK_POLYGON_MODE_FILL`, or `VK_POLYGON_MODE_FILL_RECTANGLE_NV`, by an implementation-dependent ordering of the new primitives generated within the original primitive.

Primitive order is later used to define rasterization order, which determines the order in which fragments output results to a framebuffer.

### 20.3. Programmable Primitive Shading

Once primitives are assembled, they proceed to the vertex shading stage of the pipeline. If the draw includes multiple instances, then the set of primitives is sent to the vertex shading stage multiple times, once for each instance.

It is implementation-dependent whether vertex shading occurs on vertices that are discarded as part of incomplete primitives, but if it does occur then it operates as if they were vertices in complete primitives and such invocations can have side effects.

Vertex shading receives two per-vertex inputs from the primitive assembly stage - the `vertexIndex` and the `instanceIndex`. How these values are generated is defined below, with each command.

Drawing commands fall roughly into two categories:

- Non-indexed drawing commands present a sequential `vertexIndex` to the vertex shader. The sequential index is generated automatically by the device (see Fixed-Function Vertex Processing for details on both specifying the vertex attributes indexed by `vertexIndex`, as well as binding vertex buffers containing those attributes to a command buffer). These commands are:

  - vkCmdDraw

  - vkCmdDrawIndirect

  - vkCmdDrawIndirectCount

  - vkCmdDrawIndirectCountKHR

  - vkCmdDrawIndirectCountAMD

- Indexed drawing commands read index values from an index buffer and use this to compute the `vertexIndex` value for the vertex shader. These commands are:

  - vkCmdDrawIndexed

  - vkCmdDrawIndexedIndirect

  - vkCmdDrawIndexedIndirectCount

  - vkCmdDrawIndexedIndirectCountKHR

  - vkCmdDrawIndexedIndirectCountAMD

To bind an index buffer to a command buffer, call:

    void vkCmdBindIndexBuffer(
        VkCommandBuffer                             commandBuffer,
        VkBuffer                                    buffer,
        VkDeviceSize                                offset,
        VkIndexType                                 indexType);

- `commandBuffer` is the command buffer into which the command is recorded.

- `buffer` is the buffer being bound.

- `offset` is the starting offset in bytes within `buffer` used in index buffer address calculations.

- `indexType` is a VkIndexType value specifying whether indices are treated as 16 bits or 32 bits.

Valid Usage

- `offset` must be less than the size of `buffer`

- The sum of `offset` and the address of the range of `VkDeviceMemory` object that is backing `buffer`, must be a multiple of the type indicated by `indexType`

- `buffer` must have been created with the `VK_BUFFER_USAGE_INDEX_BUFFER_BIT` flag

- If `buffer` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `indexType` must not be `VK_INDEX_TYPE_NONE_KHR`.

- If `indexType` is `VK_INDEX_TYPE_UINT8_EXT`, the indexTypeUint8 feature must be enabled

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `buffer` must be a valid VkBuffer handle

- `indexType` must be a valid VkIndexType value

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- Both of `buffer`, and `commandBuffer` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics |

Possible values of vkCmdBindIndexBuffer::`indexType`, specifying the size of indices, are:

    typedef enum VkIndexType {
        VK_INDEX_TYPE_UINT16 = 0,
        VK_INDEX_TYPE_UINT32 = 1,
        VK_INDEX_TYPE_NONE_KHR = 1000165000,
        VK_INDEX_TYPE_UINT8_EXT = 1000265000,
        VK_INDEX_TYPE_NONE_NV = VK_INDEX_TYPE_NONE_KHR,
        VK_INDEX_TYPE_MAX_ENUM = 0x7FFFFFFF
    } VkIndexType;

- `VK_INDEX_TYPE_UINT16` specifies that indices are 16-bit unsigned integer values.

- `VK_INDEX_TYPE_UINT32` specifies that indices are 32-bit unsigned integer values.

- `VK_INDEX_TYPE_NONE_KHR` specifies that no indices are provided.

- `VK_INDEX_TYPE_UINT8_EXT` specifies that indices are 8-bit unsigned integer values.

The parameters for each drawing command are specified directly in the command or read from buffer memory, depending on the command. Drawing commands that source their parameters from buffer memory are known as indirect drawing commands.

All drawing commands interact with the Robust Buffer Access feature.

To record a non-indexed draw, call:

    void vkCmdDraw(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    vertexCount,
        uint32_t                                    instanceCount,
        uint32_t                                    firstVertex,
        uint32_t                                    firstInstance);

- `commandBuffer` is the command buffer into which the command is recorded.

- `vertexCount` is the number of vertices to draw.

- `instanceCount` is the number of instances to draw.

- `firstVertex` is the index of the first vertex to draw.

- `firstInstance` is the instance ID of the first instance to draw.

When the command is executed, primitives are assembled using the current primitive topology and `vertexCount` consecutive vertex indices with the first `vertexIndex` value equal to `firstVertex`. The primitives are drawn `instanceCount` times with `instanceIndex` starting with `firstInstance` and increasing sequentially for each instance. The assembled primitives execute the bound graphics pipeline.

Valid Usage

- If a `VkImageView` is sampled with `VK_FILTER_LINEAR` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT`

- If a `VkImageView` is accessed using atomic operations as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT`

- If a `VkImageView` is sampled with `VK_FILTER_CUBIC_EXT` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_EXT`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` as a result of this command must have a VkImageViewType and format that supports cubic filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubic` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` with a reduction mode of either `VK_SAMPLER_REDUCTION_MODE_MIN` or `VK_SAMPLER_REDUCTION_MODE_MAX` as a result of this command must have a VkImageViewType and format that supports cubic filtering together with minmax filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubicMinmax` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImage created with a VkImageCreateInfo::`flags` containing `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV` sampled as a result of this command must only be sampled using a VkSamplerAddressMode of `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`.

- For each set n that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a descriptor set must have been bound to n at the same pipeline bind point, with a `VkPipelineLayout` that is compatible for set n, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- For each push constant that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a push constant value must have been set for the same pipeline bind point, with a `VkPipelineLayout` that is compatible for push constants, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- Descriptors in each bound descriptor set, specified via `vkCmdBindDescriptorSets`, must be valid if they are statically used by the `VkPipeline` bound to the pipeline bind point used by this command

- A valid pipeline must be bound to the pipeline bind point used by this command

- If the `VkPipeline` object bound to the pipeline bind point used by this command requires any dynamic state, that state must have been set for `commandBuffer`, and done so after any previously bound pipeline with the corresponding state not specified as dynamic

- There must not have been any calls to dynamic state setting commands for any state not specified as dynamic in the `VkPipeline` object bound to the pipeline bind point used by this command, since that pipeline was bound

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used to sample from any `VkImage` with a `VkImageView` of the type `VK_IMAGE_VIEW_TYPE_3D`, `VK_IMAGE_VIEW_TYPE_CUBE`, `VK_IMAGE_VIEW_TYPE_1D_ARRAY`, `VK_IMAGE_VIEW_TYPE_2D_ARRAY` or `VK_IMAGE_VIEW_TYPE_CUBE_ARRAY`, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions with `ImplicitLod`, `Dref` or `Proj` in their name, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions that includes a LOD bias or any offset values, in any shader stage

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a uniform buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a storage buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If `commandBuffer` is an unprotected command buffer, any resource accessed by the `VkPipeline` object bound to the pipeline bind point used by this command must not be a protected resource

- The current render pass must be compatible with the `renderPass` member of the `VkGraphicsPipelineCreateInfo` structure specified when creating the `VkPipeline` bound to `VK_PIPELINE_BIND_POINT_GRAPHICS`.

- The subpass index of the current render pass must be equal to the `subpass` member of the `VkGraphicsPipelineCreateInfo` structure specified when creating the `VkPipeline` bound to `VK_PIPELINE_BIND_POINT_GRAPHICS`.

- Every input attachment used by the current subpass must be bound to the pipeline via a descriptor set

- Image subresources used as attachments in the current render pass must not be accessed in any way other than as an attachment by this command.

- If the draw is recorded in a render pass instance with multiview enabled, the maximum instance index must be less than or equal to VkPhysicalDeviceMultiviewProperties::`maxMultiviewInstanceIndex`.

- If the bound graphics pipeline was created with VkPipelineSampleLocationsStateCreateInfoEXT::`sampleLocationsEnable` set to `VK_TRUE` and the current subpass has a depth/stencil attachment, then that attachment must have been created with the `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT` bit set

- If `commandBuffer` is a protected command buffer, any resource written to by the `VkPipeline` object bound to the pipeline bind point used by this command must not be an unprotected resource

- If `commandBuffer` is a protected command buffer, pipeline stages other than the framebuffer-space and compute stages in the `VkPipeline` object bound to the pipeline bind point must not write to any resource

- All vertex input bindings accessed via vertex input variables declared in the vertex shader entry point’s interface must have valid buffers bound

- For a given vertex buffer binding, any attribute data fetched must be entirely contained within the corresponding vertex buffer binding, as described in Vertex Input Description

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- This command must only be called inside of a render pass instance

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Inside | Graphics | Graphics

To record an indexed draw, call:

    void vkCmdDrawIndexed(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    indexCount,
        uint32_t                                    instanceCount,
        uint32_t                                    firstIndex,
        int32_t                                     vertexOffset,
        uint32_t                                    firstInstance);

- `commandBuffer` is the command buffer into which the command is recorded.

- `indexCount` is the number of vertices to draw.

- `instanceCount` is the number of instances to draw.

- `firstIndex` is the base index within the index buffer.

- `vertexOffset` is the value added to the vertex index before indexing into the vertex buffer.

- `firstInstance` is the instance ID of the first instance to draw.

When the command is executed, primitives are assembled using the current primitive topology and `indexCount` vertices whose indices are retrieved from the index buffer. The index buffer is treated as an array of tightly packed unsigned integers of size defined by the vkCmdBindIndexBuffer::`indexType` parameter with which the buffer was bound.

The first vertex index is at an offset of `firstIndex` * `indexSize` + `offset` within the bound index buffer, where `offset` is the offset specified by `vkCmdBindIndexBuffer` and `indexSize` is the byte size of the type specified by `indexType`. Subsequent index values are retrieved from consecutive locations in the index buffer. Indices are first compared to the primitive restart value, then zero extended to 32 bits (if the `indexType` is `VK_INDEX_TYPE_UINT8_EXT` or `VK_INDEX_TYPE_UINT16`) and have `vertexOffset` added to them, before being supplied as the `vertexIndex` value.

The primitives are drawn `instanceCount` times with `instanceIndex` starting with `firstInstance` and increasing sequentially for each instance. The assembled primitives execute the bound graphics pipeline.

Valid Usage

- If a `VkImageView` is sampled with `VK_FILTER_LINEAR` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT`

- If a `VkImageView` is accessed using atomic operations as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT`

- If a `VkImageView` is sampled with `VK_FILTER_CUBIC_EXT` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_EXT`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` as a result of this command must have a VkImageViewType and format that supports cubic filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubic` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` with a reduction mode of either `VK_SAMPLER_REDUCTION_MODE_MIN` or `VK_SAMPLER_REDUCTION_MODE_MAX` as a result of this command must have a VkImageViewType and format that supports cubic filtering together with minmax filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubicMinmax` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImage created with a VkImageCreateInfo::`flags` containing `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV` sampled as a result of this command must only be sampled using a VkSamplerAddressMode of `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`.

- For each set n that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a descriptor set must have been bound to n at the same pipeline bind point, with a `VkPipelineLayout` that is compatible for set n, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- For each push constant that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a push constant value must have been set for the same pipeline bind point, with a `VkPipelineLayout` that is compatible for push constants, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- Descriptors in each bound descriptor set, specified via `vkCmdBindDescriptorSets`, must be valid if they are statically used by the `VkPipeline` bound to the pipeline bind point used by this command

- A valid pipeline must be bound to the pipeline bind point used by this command

- If the `VkPipeline` object bound to the pipeline bind point used by this command requires any dynamic state, that state must have been set for `commandBuffer`, and done so after any previously bound pipeline with the corresponding state not specified as dynamic

- There must not have been any calls to dynamic state setting commands for any state not specified as dynamic in the `VkPipeline` object bound to the pipeline bind point used by this command, since that pipeline was bound

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used to sample from any `VkImage` with a `VkImageView` of the type `VK_IMAGE_VIEW_TYPE_3D`, `VK_IMAGE_VIEW_TYPE_CUBE`, `VK_IMAGE_VIEW_TYPE_1D_ARRAY`, `VK_IMAGE_VIEW_TYPE_2D_ARRAY` or `VK_IMAGE_VIEW_TYPE_CUBE_ARRAY`, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions with `ImplicitLod`, `Dref` or `Proj` in their name, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions that includes a LOD bias or any offset values, in any shader stage

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a uniform buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a storage buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If `commandBuffer` is an unprotected command buffer, any resource accessed by the `VkPipeline` object bound to the pipeline bind point used by this command must not be a protected resource

- The current render pass must be compatible with the `renderPass` member of the `VkGraphicsPipelineCreateInfo` structure specified when creating the `VkPipeline` bound to `VK_PIPELINE_BIND_POINT_GRAPHICS`.

- The subpass index of the current render pass must be equal to the `subpass` member of the `VkGraphicsPipelineCreateInfo` structure specified when creating the `VkPipeline` bound to `VK_PIPELINE_BIND_POINT_GRAPHICS`.

- Every input attachment used by the current subpass must be bound to the pipeline via a descriptor set

- Image subresources used as attachments in the current render pass must not be accessed in any way other than as an attachment by this command.

- If the draw is recorded in a render pass instance with multiview enabled, the maximum instance index must be less than or equal to VkPhysicalDeviceMultiviewProperties::`maxMultiviewInstanceIndex`.

- If the bound graphics pipeline was created with VkPipelineSampleLocationsStateCreateInfoEXT::`sampleLocationsEnable` set to `VK_TRUE` and the current subpass has a depth/stencil attachment, then that attachment must have been created with the `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT` bit set

- If `commandBuffer` is a protected command buffer, any resource written to by the `VkPipeline` object bound to the pipeline bind point used by this command must not be an unprotected resource

- If `commandBuffer` is a protected command buffer, pipeline stages other than the framebuffer-space and compute stages in the `VkPipeline` object bound to the pipeline bind point must not write to any resource

- All vertex input bindings accessed via vertex input variables declared in the vertex shader entry point’s interface must have valid buffers bound

- For a given vertex buffer binding, any attribute data fetched must be entirely contained within the corresponding vertex buffer binding, as described in Vertex Input Description

- (`indexSize` * (`firstIndex` + `indexCount`) + `offset`) must be less than or equal to the size of the bound index buffer, with `indexSize` being based on the type specified by `indexType`, where the index buffer, `indexType`, and `offset` are specified via `vkCmdBindIndexBuffer`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- This command must only be called inside of a render pass instance

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Inside | Graphics | Graphics

To record a non-indexed indirect draw, call:

    void vkCmdDrawIndirect(
        VkCommandBuffer                             commandBuffer,
        VkBuffer                                    buffer,
        VkDeviceSize                                offset,
        uint32_t                                    drawCount,
        uint32_t                                    stride);

- `commandBuffer` is the command buffer into which the command is recorded.

- `buffer` is the buffer containing draw parameters.

- `offset` is the byte offset into `buffer` where parameters begin.

- `drawCount` is the number of draws to execute, and can be zero.

- `stride` is the byte stride between successive sets of draw parameters.

`vkCmdDrawIndirect` behaves similarly to vkCmdDraw except that the parameters are read by the device from a buffer during execution. `drawCount` draws are executed by the command, with parameters taken from `buffer` starting at `offset` and increasing by `stride` bytes for each successive draw. The parameters of each draw are encoded in an array of VkDrawIndirectCommand structures. If `drawCount` is less than or equal to one, `stride` is ignored.

Valid Usage

- If a `VkImageView` is sampled with `VK_FILTER_LINEAR` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT`

- If a `VkImageView` is accessed using atomic operations as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT`

- If a `VkImageView` is sampled with `VK_FILTER_CUBIC_EXT` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_EXT`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` as a result of this command must have a VkImageViewType and format that supports cubic filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubic` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` with a reduction mode of either `VK_SAMPLER_REDUCTION_MODE_MIN` or `VK_SAMPLER_REDUCTION_MODE_MAX` as a result of this command must have a VkImageViewType and format that supports cubic filtering together with minmax filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubicMinmax` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImage created with a VkImageCreateInfo::`flags` containing `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV` sampled as a result of this command must only be sampled using a VkSamplerAddressMode of `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`.

- For each set n that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a descriptor set must have been bound to n at the same pipeline bind point, with a `VkPipelineLayout` that is compatible for set n, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- For each push constant that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a push constant value must have been set for the same pipeline bind point, with a `VkPipelineLayout` that is compatible for push constants, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- Descriptors in each bound descriptor set, specified via `vkCmdBindDescriptorSets`, must be valid if they are statically used by the `VkPipeline` bound to the pipeline bind point used by this command

- A valid pipeline must be bound to the pipeline bind point used by this command

- If the `VkPipeline` object bound to the pipeline bind point used by this command requires any dynamic state, that state must have been set for `commandBuffer`, and done so after any previously bound pipeline with the corresponding state not specified as dynamic

- There must not have been any calls to dynamic state setting commands for any state not specified as dynamic in the `VkPipeline` object bound to the pipeline bind point used by this command, since that pipeline was bound

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used to sample from any `VkImage` with a `VkImageView` of the type `VK_IMAGE_VIEW_TYPE_3D`, `VK_IMAGE_VIEW_TYPE_CUBE`, `VK_IMAGE_VIEW_TYPE_1D_ARRAY`, `VK_IMAGE_VIEW_TYPE_2D_ARRAY` or `VK_IMAGE_VIEW_TYPE_CUBE_ARRAY`, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions with `ImplicitLod`, `Dref` or `Proj` in their name, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions that includes a LOD bias or any offset values, in any shader stage

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a uniform buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a storage buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If `commandBuffer` is an unprotected command buffer, any resource accessed by the `VkPipeline` object bound to the pipeline bind point used by this command must not be a protected resource

- The current render pass must be compatible with the `renderPass` member of the `VkGraphicsPipelineCreateInfo` structure specified when creating the `VkPipeline` bound to `VK_PIPELINE_BIND_POINT_GRAPHICS`.

- The subpass index of the current render pass must be equal to the `subpass` member of the `VkGraphicsPipelineCreateInfo` structure specified when creating the `VkPipeline` bound to `VK_PIPELINE_BIND_POINT_GRAPHICS`.

- Every input attachment used by the current subpass must be bound to the pipeline via a descriptor set

- Image subresources used as attachments in the current render pass must not be accessed in any way other than as an attachment by this command.

- If the draw is recorded in a render pass instance with multiview enabled, the maximum instance index must be less than or equal to VkPhysicalDeviceMultiviewProperties::`maxMultiviewInstanceIndex`.

- If the bound graphics pipeline was created with VkPipelineSampleLocationsStateCreateInfoEXT::`sampleLocationsEnable` set to `VK_TRUE` and the current subpass has a depth/stencil attachment, then that attachment must have been created with the `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT` bit set

- All vertex input bindings accessed via vertex input variables declared in the vertex shader entry point’s interface must have valid buffers bound

- For a given vertex buffer binding, any attribute data fetched must be entirely contained within the corresponding vertex buffer binding, as described in Vertex Input Description

- If `buffer` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `buffer` must have been created with the `VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT` bit set

- `offset` must be a multiple of `4`

- `commandBuffer` must not be a protected command buffer

- If the multi-draw indirect feature is not enabled, `drawCount` must be `0` or `1`

- `drawCount` must be less than or equal to `VkPhysicalDeviceLimits`::`maxDrawIndirectCount`

- If the drawIndirectFirstInstance feature is not enabled, all the `firstInstance` members of the `VkDrawIndirectCommand` structures accessed by this command must be `0`

- If `drawCount` is greater than `1`, `stride` must be a multiple of `4` and must be greater than or equal to `sizeof`(`VkDrawIndirectCommand`)

- If `drawCount` is equal to `1`, (`offset` + `sizeof`(VkDrawIndirectCommand)) must be less than or equal to the size of `buffer`

- If `drawCount` is greater than `1`, (`stride` × (`drawCount` - 1) + `offset` + `sizeof`(VkDrawIndirectCommand)) must be less than or equal to the size of `buffer`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `buffer` must be a valid VkBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- This command must only be called inside of a render pass instance

- Both of `buffer`, and `commandBuffer` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Inside | Graphics | Graphics

The `VkDrawIndirectCommand` structure is defined as:

    typedef struct VkDrawIndirectCommand {
        uint32_t    vertexCount;
        uint32_t    instanceCount;
        uint32_t    firstVertex;
        uint32_t    firstInstance;
    } VkDrawIndirectCommand;

- `vertexCount` is the number of vertices to draw.

- `instanceCount` is the number of instances to draw.

- `firstVertex` is the index of the first vertex to draw.

- `firstInstance` is the instance ID of the first instance to draw.

The members of `VkDrawIndirectCommand` have the same meaning as the similarly named parameters of vkCmdDraw.

Valid Usage

- For a given vertex buffer binding, any attribute data fetched must be entirely contained within the corresponding vertex buffer binding, as described in Vertex Input Description

- If the drawIndirectFirstInstance feature is not enabled, `firstInstance` must be `0`

To record a non-indexed draw call with a draw call count sourced from a buffer, call:

    void vkCmdDrawIndirectCount(
        VkCommandBuffer                             commandBuffer,
        VkBuffer                                    buffer,
        VkDeviceSize                                offset,
        VkBuffer                                    countBuffer,
        VkDeviceSize                                countBufferOffset,
        uint32_t                                    maxDrawCount,
        uint32_t                                    stride);

or the equivalent command

    void vkCmdDrawIndirectCountKHR(
        VkCommandBuffer                             commandBuffer,
        VkBuffer                                    buffer,
        VkDeviceSize                                offset,
        VkBuffer                                    countBuffer,
        VkDeviceSize                                countBufferOffset,
        uint32_t                                    maxDrawCount,
        uint32_t                                    stride);

or the equivalent command

    void vkCmdDrawIndirectCountAMD(
        VkCommandBuffer                             commandBuffer,
        VkBuffer                                    buffer,
        VkDeviceSize                                offset,
        VkBuffer                                    countBuffer,
        VkDeviceSize                                countBufferOffset,
        uint32_t                                    maxDrawCount,
        uint32_t                                    stride);

- `commandBuffer` is the command buffer into which the command is recorded.

- `buffer` is the buffer containing draw parameters.

- `offset` is the byte offset into `buffer` where parameters begin.

- `countBuffer` is the buffer containing the draw count.

- `countBufferOffset` is the byte offset into `countBuffer` where the draw count begins.

- `maxDrawCount` specifies the maximum number of draws that will be executed. The actual number of executed draw calls is the minimum of the count specified in `countBuffer` and `maxDrawCount`.

- `stride` is the byte stride between successive sets of draw parameters.

`vkCmdDrawIndirectCount` behaves similarly to vkCmdDrawIndirect except that the draw count is read by the device from a buffer during execution. The command will read an unsigned 32-bit integer from `countBuffer` located at `countBufferOffset` and use this as the draw count.

Valid Usage

- If a `VkImageView` is sampled with `VK_FILTER_LINEAR` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT`

- If a `VkImageView` is accessed using atomic operations as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT`

- If a `VkImageView` is sampled with `VK_FILTER_CUBIC_EXT` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_EXT`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` as a result of this command must have a VkImageViewType and format that supports cubic filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubic` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` with a reduction mode of either `VK_SAMPLER_REDUCTION_MODE_MIN` or `VK_SAMPLER_REDUCTION_MODE_MAX` as a result of this command must have a VkImageViewType and format that supports cubic filtering together with minmax filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubicMinmax` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImage created with a VkImageCreateInfo::`flags` containing `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV` sampled as a result of this command must only be sampled using a VkSamplerAddressMode of `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`.

- For each set n that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a descriptor set must have been bound to n at the same pipeline bind point, with a `VkPipelineLayout` that is compatible for set n, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- For each push constant that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a push constant value must have been set for the same pipeline bind point, with a `VkPipelineLayout` that is compatible for push constants, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- Descriptors in each bound descriptor set, specified via `vkCmdBindDescriptorSets`, must be valid if they are statically used by the `VkPipeline` bound to the pipeline bind point used by this command

- A valid pipeline must be bound to the pipeline bind point used by this command

- If the `VkPipeline` object bound to the pipeline bind point used by this command requires any dynamic state, that state must have been set for `commandBuffer`, and done so after any previously bound pipeline with the corresponding state not specified as dynamic

- There must not have been any calls to dynamic state setting commands for any state not specified as dynamic in the `VkPipeline` object bound to the pipeline bind point used by this command, since that pipeline was bound

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used to sample from any `VkImage` with a `VkImageView` of the type `VK_IMAGE_VIEW_TYPE_3D`, `VK_IMAGE_VIEW_TYPE_CUBE`, `VK_IMAGE_VIEW_TYPE_1D_ARRAY`, `VK_IMAGE_VIEW_TYPE_2D_ARRAY` or `VK_IMAGE_VIEW_TYPE_CUBE_ARRAY`, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions with `ImplicitLod`, `Dref` or `Proj` in their name, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions that includes a LOD bias or any offset values, in any shader stage

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a uniform buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a storage buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If `commandBuffer` is an unprotected command buffer, any resource accessed by the `VkPipeline` object bound to the pipeline bind point used by this command must not be a protected resource

- The current render pass must be compatible with the `renderPass` member of the `VkGraphicsPipelineCreateInfo` structure specified when creating the `VkPipeline` bound to `VK_PIPELINE_BIND_POINT_GRAPHICS`.

- The subpass index of the current render pass must be equal to the `subpass` member of the `VkGraphicsPipelineCreateInfo` structure specified when creating the `VkPipeline` bound to `VK_PIPELINE_BIND_POINT_GRAPHICS`.

- Every input attachment used by the current subpass must be bound to the pipeline via a descriptor set

- Image subresources used as attachments in the current render pass must not be accessed in any way other than as an attachment by this command.

- If the draw is recorded in a render pass instance with multiview enabled, the maximum instance index must be less than or equal to VkPhysicalDeviceMultiviewProperties::`maxMultiviewInstanceIndex`.

- If the bound graphics pipeline was created with VkPipelineSampleLocationsStateCreateInfoEXT::`sampleLocationsEnable` set to `VK_TRUE` and the current subpass has a depth/stencil attachment, then that attachment must have been created with the `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT` bit set

- All vertex input bindings accessed via vertex input variables declared in the vertex shader entry point’s interface must have valid buffers bound

- For a given vertex buffer binding, any attribute data fetched must be entirely contained within the corresponding vertex buffer binding, as described in Vertex Input Description

- If `buffer` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `buffer` must have been created with the `VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT` bit set

- `offset` must be a multiple of `4`

- `commandBuffer` must not be a protected command buffer

- If `countBuffer` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `countBuffer` must have been created with the `VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT` bit set

- `countBufferOffset` must be a multiple of `4`

- The count stored in `countBuffer` must be less than or equal to `VkPhysicalDeviceLimits`::`maxDrawIndirectCount`

- `stride` must be a multiple of `4` and must be greater than or equal to sizeof(`VkDrawIndirectCommand`)

- If `maxDrawCount` is greater than or equal to `1`, (`stride` × (`maxDrawCount` - 1) + `offset` + sizeof(`VkDrawIndirectCommand`)) must be less than or equal to the size of `buffer`

- If the count stored in `countBuffer` is equal to `1`, (`offset` + sizeof(`VkDrawIndirectCommand`)) must be less than or equal to the size of `buffer`

- If the count stored in `countBuffer` is greater than `1`, (`stride` × (`drawCount` - 1) + `offset` + sizeof(`VkDrawIndirectCommand`)) must be less than or equal to the size of `buffer`

- If drawIndirectCount is not enabled this function must not be used

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `buffer` must be a valid VkBuffer handle

- `countBuffer` must be a valid VkBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- This command must only be called inside of a render pass instance

- Each of `buffer`, `commandBuffer`, and `countBuffer` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Inside | Graphics | Graphics

To record an indexed indirect draw, call:

    void vkCmdDrawIndexedIndirect(
        VkCommandBuffer                             commandBuffer,
        VkBuffer                                    buffer,
        VkDeviceSize                                offset,
        uint32_t                                    drawCount,
        uint32_t                                    stride);

- `commandBuffer` is the command buffer into which the command is recorded.

- `buffer` is the buffer containing draw parameters.

- `offset` is the byte offset into `buffer` where parameters begin.

- `drawCount` is the number of draws to execute, and can be zero.

- `stride` is the byte stride between successive sets of draw parameters.

`vkCmdDrawIndexedIndirect` behaves similarly to vkCmdDrawIndexed except that the parameters are read by the device from a buffer during execution. `drawCount` draws are executed by the command, with parameters taken from `buffer` starting at `offset` and increasing by `stride` bytes for each successive draw. The parameters of each draw are encoded in an array of VkDrawIndexedIndirectCommand structures. If `drawCount` is less than or equal to one, `stride` is ignored.

Valid Usage

- If a `VkImageView` is sampled with `VK_FILTER_LINEAR` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT`

- If a `VkImageView` is accessed using atomic operations as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT`

- If a `VkImageView` is sampled with `VK_FILTER_CUBIC_EXT` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_EXT`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` as a result of this command must have a VkImageViewType and format that supports cubic filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubic` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` with a reduction mode of either `VK_SAMPLER_REDUCTION_MODE_MIN` or `VK_SAMPLER_REDUCTION_MODE_MAX` as a result of this command must have a VkImageViewType and format that supports cubic filtering together with minmax filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubicMinmax` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImage created with a VkImageCreateInfo::`flags` containing `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV` sampled as a result of this command must only be sampled using a VkSamplerAddressMode of `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`.

- For each set n that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a descriptor set must have been bound to n at the same pipeline bind point, with a `VkPipelineLayout` that is compatible for set n, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- For each push constant that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a push constant value must have been set for the same pipeline bind point, with a `VkPipelineLayout` that is compatible for push constants, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- Descriptors in each bound descriptor set, specified via `vkCmdBindDescriptorSets`, must be valid if they are statically used by the `VkPipeline` bound to the pipeline bind point used by this command

- A valid pipeline must be bound to the pipeline bind point used by this command

- If the `VkPipeline` object bound to the pipeline bind point used by this command requires any dynamic state, that state must have been set for `commandBuffer`, and done so after any previously bound pipeline with the corresponding state not specified as dynamic

- There must not have been any calls to dynamic state setting commands for any state not specified as dynamic in the `VkPipeline` object bound to the pipeline bind point used by this command, since that pipeline was bound

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used to sample from any `VkImage` with a `VkImageView` of the type `VK_IMAGE_VIEW_TYPE_3D`, `VK_IMAGE_VIEW_TYPE_CUBE`, `VK_IMAGE_VIEW_TYPE_1D_ARRAY`, `VK_IMAGE_VIEW_TYPE_2D_ARRAY` or `VK_IMAGE_VIEW_TYPE_CUBE_ARRAY`, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions with `ImplicitLod`, `Dref` or `Proj` in their name, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions that includes a LOD bias or any offset values, in any shader stage

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a uniform buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a storage buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If `commandBuffer` is an unprotected command buffer, any resource accessed by the `VkPipeline` object bound to the pipeline bind point used by this command must not be a protected resource

- The current render pass must be compatible with the `renderPass` member of the `VkGraphicsPipelineCreateInfo` structure specified when creating the `VkPipeline` bound to `VK_PIPELINE_BIND_POINT_GRAPHICS`.

- The subpass index of the current render pass must be equal to the `subpass` member of the `VkGraphicsPipelineCreateInfo` structure specified when creating the `VkPipeline` bound to `VK_PIPELINE_BIND_POINT_GRAPHICS`.

- Every input attachment used by the current subpass must be bound to the pipeline via a descriptor set

- Image subresources used as attachments in the current render pass must not be accessed in any way other than as an attachment by this command.

- If the draw is recorded in a render pass instance with multiview enabled, the maximum instance index must be less than or equal to VkPhysicalDeviceMultiviewProperties::`maxMultiviewInstanceIndex`.

- If the bound graphics pipeline was created with VkPipelineSampleLocationsStateCreateInfoEXT::`sampleLocationsEnable` set to `VK_TRUE` and the current subpass has a depth/stencil attachment, then that attachment must have been created with the `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT` bit set

- All vertex input bindings accessed via vertex input variables declared in the vertex shader entry point’s interface must have valid buffers bound

- For a given vertex buffer binding, any attribute data fetched must be entirely contained within the corresponding vertex buffer binding, as described in Vertex Input Description

- If `buffer` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `buffer` must have been created with the `VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT` bit set

- `offset` must be a multiple of `4`

- `commandBuffer` must not be a protected command buffer

- If the multi-draw indirect feature is not enabled, `drawCount` must be `0` or `1`

- `drawCount` must be less than or equal to `VkPhysicalDeviceLimits`::`maxDrawIndirectCount`

- If `drawCount` is greater than `1`, `stride` must be a multiple of `4` and must be greater than or equal to `sizeof`(`VkDrawIndexedIndirectCommand`)

- If the drawIndirectFirstInstance feature is not enabled, all the `firstInstance` members of the `VkDrawIndexedIndirectCommand` structures accessed by this command must be `0`

- If `drawCount` is equal to `1`, (`offset` + `sizeof`(`VkDrawIndexedIndirectCommand`)) must be less than or equal to the size of `buffer`

- If `drawCount` is greater than `1`, (`stride` × (`drawCount` - 1) + `offset` + `sizeof`(`VkDrawIndexedIndirectCommand`)) must be less than or equal to the size of `buffer`

- If drawIndirectCount is not enabled this function must not be used

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `buffer` must be a valid VkBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- This command must only be called inside of a render pass instance

- Both of `buffer`, and `commandBuffer` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Inside | Graphics | Graphics

The `VkDrawIndexedIndirectCommand` structure is defined as:

    typedef struct VkDrawIndexedIndirectCommand {
        uint32_t    indexCount;
        uint32_t    instanceCount;
        uint32_t    firstIndex;
        int32_t     vertexOffset;
        uint32_t    firstInstance;
    } VkDrawIndexedIndirectCommand;

- `indexCount` is the number of vertices to draw.

- `instanceCount` is the number of instances to draw.

- `firstIndex` is the base index within the index buffer.

- `vertexOffset` is the value added to the vertex index before indexing into the vertex buffer.

- `firstInstance` is the instance ID of the first instance to draw.

The members of `VkDrawIndexedIndirectCommand` have the same meaning as the similarly named parameters of vkCmdDrawIndexed.

Valid Usage

- For a given vertex buffer binding, any attribute data fetched must be entirely contained within the corresponding vertex buffer binding, as described in Vertex Input Description

- (`indexSize` * (`firstIndex` + `indexCount`) + `offset`) must be less than or equal to the size of the bound index buffer, with `indexSize` being based on the type specified by `indexType`, where the index buffer, `indexType`, and `offset` are specified via `vkCmdBindIndexBuffer`

- If the drawIndirectFirstInstance feature is not enabled, `firstInstance` must be `0`

To record an indexed draw call with a draw call count sourced from a buffer, call:

    void vkCmdDrawIndexedIndirectCount(
        VkCommandBuffer                             commandBuffer,
        VkBuffer                                    buffer,
        VkDeviceSize                                offset,
        VkBuffer                                    countBuffer,
        VkDeviceSize                                countBufferOffset,
        uint32_t                                    maxDrawCount,
        uint32_t                                    stride);

or the equivalent command

    void vkCmdDrawIndexedIndirectCountKHR(
        VkCommandBuffer                             commandBuffer,
        VkBuffer                                    buffer,
        VkDeviceSize                                offset,
        VkBuffer                                    countBuffer,
        VkDeviceSize                                countBufferOffset,
        uint32_t                                    maxDrawCount,
        uint32_t                                    stride);

or the equivalent command

    void vkCmdDrawIndexedIndirectCountAMD(
        VkCommandBuffer                             commandBuffer,
        VkBuffer                                    buffer,
        VkDeviceSize                                offset,
        VkBuffer                                    countBuffer,
        VkDeviceSize                                countBufferOffset,
        uint32_t                                    maxDrawCount,
        uint32_t                                    stride);

- `commandBuffer` is the command buffer into which the command is recorded.

- `buffer` is the buffer containing draw parameters.

- `offset` is the byte offset into `buffer` where parameters begin.

- `countBuffer` is the buffer containing the draw count.

- `countBufferOffset` is the byte offset into `countBuffer` where the draw count begins.

- `maxDrawCount` specifies the maximum number of draws that will be executed. The actual number of executed draw calls is the minimum of the count specified in `countBuffer` and `maxDrawCount`.

- `stride` is the byte stride between successive sets of draw parameters.

`vkCmdDrawIndexedIndirectCount` behaves similarly to vkCmdDrawIndexedIndirect except that the draw count is read by the device from a buffer during execution. The command will read an unsigned 32-bit integer from `countBuffer` located at `countBufferOffset` and use this as the draw count.

Valid Usage

- If a `VkImageView` is sampled with `VK_FILTER_LINEAR` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT`

- If a `VkImageView` is accessed using atomic operations as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT`

- If a `VkImageView` is sampled with `VK_FILTER_CUBIC_EXT` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_EXT`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` as a result of this command must have a VkImageViewType and format that supports cubic filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubic` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` with a reduction mode of either `VK_SAMPLER_REDUCTION_MODE_MIN` or `VK_SAMPLER_REDUCTION_MODE_MAX` as a result of this command must have a VkImageViewType and format that supports cubic filtering together with minmax filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubicMinmax` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImage created with a VkImageCreateInfo::`flags` containing `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV` sampled as a result of this command must only be sampled using a VkSamplerAddressMode of `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`.

- For each set n that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a descriptor set must have been bound to n at the same pipeline bind point, with a `VkPipelineLayout` that is compatible for set n, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- For each push constant that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a push constant value must have been set for the same pipeline bind point, with a `VkPipelineLayout` that is compatible for push constants, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- Descriptors in each bound descriptor set, specified via `vkCmdBindDescriptorSets`, must be valid if they are statically used by the `VkPipeline` bound to the pipeline bind point used by this command

- A valid pipeline must be bound to the pipeline bind point used by this command

- If the `VkPipeline` object bound to the pipeline bind point used by this command requires any dynamic state, that state must have been set for `commandBuffer`, and done so after any previously bound pipeline with the corresponding state not specified as dynamic

- There must not have been any calls to dynamic state setting commands for any state not specified as dynamic in the `VkPipeline` object bound to the pipeline bind point used by this command, since that pipeline was bound

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used to sample from any `VkImage` with a `VkImageView` of the type `VK_IMAGE_VIEW_TYPE_3D`, `VK_IMAGE_VIEW_TYPE_CUBE`, `VK_IMAGE_VIEW_TYPE_1D_ARRAY`, `VK_IMAGE_VIEW_TYPE_2D_ARRAY` or `VK_IMAGE_VIEW_TYPE_CUBE_ARRAY`, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions with `ImplicitLod`, `Dref` or `Proj` in their name, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions that includes a LOD bias or any offset values, in any shader stage

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a uniform buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a storage buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If `commandBuffer` is an unprotected command buffer, any resource accessed by the `VkPipeline` object bound to the pipeline bind point used by this command must not be a protected resource

- The current render pass must be compatible with the `renderPass` member of the `VkGraphicsPipelineCreateInfo` structure specified when creating the `VkPipeline` bound to `VK_PIPELINE_BIND_POINT_GRAPHICS`.

- The subpass index of the current render pass must be equal to the `subpass` member of the `VkGraphicsPipelineCreateInfo` structure specified when creating the `VkPipeline` bound to `VK_PIPELINE_BIND_POINT_GRAPHICS`.

- Every input attachment used by the current subpass must be bound to the pipeline via a descriptor set

- Image subresources used as attachments in the current render pass must not be accessed in any way other than as an attachment by this command.

- If the draw is recorded in a render pass instance with multiview enabled, the maximum instance index must be less than or equal to VkPhysicalDeviceMultiviewProperties::`maxMultiviewInstanceIndex`.

- If the bound graphics pipeline was created with VkPipelineSampleLocationsStateCreateInfoEXT::`sampleLocationsEnable` set to `VK_TRUE` and the current subpass has a depth/stencil attachment, then that attachment must have been created with the `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT` bit set

- All vertex input bindings accessed via vertex input variables declared in the vertex shader entry point’s interface must have valid buffers bound

- For a given vertex buffer binding, any attribute data fetched must be entirely contained within the corresponding vertex buffer binding, as described in Vertex Input Description

- If `buffer` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `buffer` must have been created with the `VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT` bit set

- `offset` must be a multiple of `4`

- `commandBuffer` must not be a protected command buffer

- If `countBuffer` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `countBuffer` must have been created with the `VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT` bit set

- `countBufferOffset` must be a multiple of `4`

- The count stored in `countBuffer` must be less than or equal to `VkPhysicalDeviceLimits`::`maxDrawIndirectCount`

- `stride` must be a multiple of `4` and must be greater than or equal to sizeof(`VkDrawIndexedIndirectCommand`)

- If `maxDrawCount` is greater than or equal to `1`, (`stride` × (`maxDrawCount` - 1) + `offset` + sizeof(`VkDrawIndexedIndirectCommand`)) must be less than or equal to the size of `buffer`

- If count stored in `countBuffer` is equal to `1`, (`offset` + sizeof(`VkDrawIndexedIndirectCommand`)) must be less than or equal to the size of `buffer`

- If count stored in `countBuffer` is greater than `1`, (`stride` × (`drawCount` - 1) + `offset` + sizeof(`VkDrawIndexedIndirectCommand`)) must be less than or equal to the size of `buffer`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `buffer` must be a valid VkBuffer handle

- `countBuffer` must be a valid VkBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- This command must only be called inside of a render pass instance

- Each of `buffer`, `commandBuffer`, and `countBuffer` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Inside | Graphics | Graphics

#### 20.3.1. Drawing Transform Feedback

It is possible to draw vertex data that was previously captured during active transform feedback by binding one or more of the transform feedback buffers as vertex buffers. A pipeline barrier is required between using the buffers as transform feedback buffers and vertex buffers to ensure all writes to the transform feedback buffers are visible when the data is read as vertex attributes. The source access is `VK_ACCESS_TRANSFORM_FEEDBACK_WRITE_BIT_EXT` and the destination access is `VK_ACCESS_VERTEX_ATTRIBUTE_READ_BIT` for the pipeline stages `VK_PIPELINE_STAGE_TRANSFORM_FEEDBACK_BIT_EXT` and `VK_PIPELINE_STAGE_VERTEX_INPUT_BIT` respectively. The value written to the counter buffer by vkCmdEndTransformFeedbackEXT can be used to determine the vertex count for the draw. A pipeline barrier is required between using the counter buffer for `vkCmdEndTransformFeedbackEXT` and `vkCmdDrawIndirectByteCountEXT` where the source access is `VK_ACCESS_TRANSFORM_FEEDBACK_COUNTER_WRITE_BIT_EXT` and the destination access is `VK_ACCESS_INDIRECT_COMMAND_READ_BIT` for the pipeline stages `VK_PIPELINE_STAGE_TRANSFORM_FEEDBACK_BIT_EXT` and `VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT` respectively.

To record a non-indexed draw call, where the vertex count is based on a byte count read from a buffer and the passed in vertex stride parameter, call:

    void vkCmdDrawIndirectByteCountEXT(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    instanceCount,
        uint32_t                                    firstInstance,
        VkBuffer                                    counterBuffer,
        VkDeviceSize                                counterBufferOffset,
        uint32_t                                    counterOffset,
        uint32_t                                    vertexStride);

- `commandBuffer` is the command buffer into which the command is recorded.

- `instanceCount` is the number of instances to draw.

- `firstInstance` is the instance ID of the first instance to draw.

- `counterBuffer` is the buffer handle from where the byte count is read.

- `counterBufferOffset` is the offset into the buffer used to read the byte count, which is used to calculate the vertex count for this draw call.

- `counterOffset` is subtracted from the byte count read from the `counterBuffer` at the `counterBufferOffset`

- `vertexStride` is the stride in bytes between each element of the vertex data that is used to calculate the vertex count from the counter value. This value is typically the same value that was used in the graphics pipeline state when the transform feedback was captured as the `XfbStride`.

When the command is executed, primitives are assembled in the same way as done with vkCmdDraw except the `vertexCount` is calculated based on the byte count read from `counterBuffer` at offset `counterBufferOffset`. The assembled primitives execute the bound graphics pipeline.

The effective `vertexCount` is calculated as follows:

    const uint32_t * counterBufferPtr = (const uint8_t *)counterBuffer.address + counterBufferOffset;
    vertexCount = floor(max(0, (*counterBufferPtr - counterOffset)) / vertexStride);

The effective `firstVertex` is zero.

Valid Usage

- If a `VkImageView` is sampled with `VK_FILTER_LINEAR` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT`

- If a `VkImageView` is accessed using atomic operations as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT`

- If a `VkImageView` is sampled with `VK_FILTER_CUBIC_EXT` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_EXT`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` as a result of this command must have a VkImageViewType and format that supports cubic filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubic` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` with a reduction mode of either `VK_SAMPLER_REDUCTION_MODE_MIN` or `VK_SAMPLER_REDUCTION_MODE_MAX` as a result of this command must have a VkImageViewType and format that supports cubic filtering together with minmax filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubicMinmax` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImage created with a VkImageCreateInfo::`flags` containing `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV` sampled as a result of this command must only be sampled using a VkSamplerAddressMode of `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`.

- For each set n that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a descriptor set must have been bound to n at the same pipeline bind point, with a `VkPipelineLayout` that is compatible for set n, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- For each push constant that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a push constant value must have been set for the same pipeline bind point, with a `VkPipelineLayout` that is compatible for push constants, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- Descriptors in each bound descriptor set, specified via `vkCmdBindDescriptorSets`, must be valid if they are statically used by the `VkPipeline` bound to the pipeline bind point used by this command

- A valid pipeline must be bound to the pipeline bind point used by this command

- If the `VkPipeline` object bound to the pipeline bind point used by this command requires any dynamic state, that state must have been set for `commandBuffer`, and done so after any previously bound pipeline with the corresponding state not specified as dynamic

- There must not have been any calls to dynamic state setting commands for any state not specified as dynamic in the `VkPipeline` object bound to the pipeline bind point used by this command, since that pipeline was bound

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used to sample from any `VkImage` with a `VkImageView` of the type `VK_IMAGE_VIEW_TYPE_3D`, `VK_IMAGE_VIEW_TYPE_CUBE`, `VK_IMAGE_VIEW_TYPE_1D_ARRAY`, `VK_IMAGE_VIEW_TYPE_2D_ARRAY` or `VK_IMAGE_VIEW_TYPE_CUBE_ARRAY`, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions with `ImplicitLod`, `Dref` or `Proj` in their name, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions that includes a LOD bias or any offset values, in any shader stage

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a uniform buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a storage buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If `commandBuffer` is an unprotected command buffer, any resource accessed by the `VkPipeline` object bound to the pipeline bind point used by this command must not be a protected resource

- The current render pass must be compatible with the `renderPass` member of the `VkGraphicsPipelineCreateInfo` structure specified when creating the `VkPipeline` bound to `VK_PIPELINE_BIND_POINT_GRAPHICS`.

- The subpass index of the current render pass must be equal to the `subpass` member of the `VkGraphicsPipelineCreateInfo` structure specified when creating the `VkPipeline` bound to `VK_PIPELINE_BIND_POINT_GRAPHICS`.

- Every input attachment used by the current subpass must be bound to the pipeline via a descriptor set

- Image subresources used as attachments in the current render pass must not be accessed in any way other than as an attachment by this command.

- If the draw is recorded in a render pass instance with multiview enabled, the maximum instance index must be less than or equal to VkPhysicalDeviceMultiviewProperties::`maxMultiviewInstanceIndex`.

- If the bound graphics pipeline was created with VkPipelineSampleLocationsStateCreateInfoEXT::`sampleLocationsEnable` set to `VK_TRUE` and the current subpass has a depth/stencil attachment, then that attachment must have been created with the `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT` bit set

- All vertex input bindings accessed via vertex input variables declared in the vertex shader entry point’s interface must have valid buffers bound

- For a given vertex buffer binding, any attribute data fetched must be entirely contained within the corresponding vertex buffer binding, as described in Vertex Input Description

- `VkPhysicalDeviceTransformFeedbackFeaturesEXT`::`transformFeedback` must be enabled

- The implementation must support `VkPhysicalDeviceTransformFeedbackPropertiesEXT`::`transformFeedbackDraw`

- `vertexStride` must be greater than 0 and less than or equal to VkPhysicalDeviceLimits::`maxTransformFeedbackBufferDataStride`

- `counterBuffer` must have been created with the `VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT` bit set

- `commandBuffer` must not be a protected command buffer

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `counterBuffer` must be a valid VkBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- This command must only be called inside of a render pass instance

- Both of `commandBuffer`, and `counterBuffer` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Inside | Graphics | Graphics

### 20.4. Conditional Rendering

Certain rendering commands can be executed conditionally based on a value in buffer memory. These rendering commands are limited to drawing commands, dispatching commands, and clearing attachments with vkCmdClearAttachments within a conditional rendering block which is defined by commands vkCmdBeginConditionalRenderingEXT and vkCmdEndConditionalRenderingEXT. Other rendering commands remain unaffected by conditional rendering.

After beginning conditional rendering, it is considered active within the command buffer it was called until it is ended with vkCmdEndConditionalRenderingEXT.

Conditional rendering must begin and end in the same command buffer. When conditional rendering is active, a primary command buffer can execute secondary command buffers if the inherited conditional rendering feature is enabled. For a secondary command buffer to be executed while conditional rendering is active in the primary command buffer, it must set the `conditionalRenderingEnable` flag of VkCommandBufferInheritanceConditionalRenderingInfoEXT, as described in the Command Buffer Recording section.

Conditional rendering must also either begin and end inside the same subpass of a render pass instance, or must both begin and end outside of a render pass instance (i.e. contain entire render pass instances).

To begin conditional rendering, call:

    void vkCmdBeginConditionalRenderingEXT(
        VkCommandBuffer                             commandBuffer,
        const VkConditionalRenderingBeginInfoEXT*   pConditionalRenderingBegin);

- `commandBuffer` is the command buffer into which this command will be recorded.

- `pConditionalRenderingBegin` is a pointer to a VkConditionalRenderingBeginInfoEXT structure specifying parameters of conditional rendering.

Valid Usage

- Conditional rendering must not already be active

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pConditionalRenderingBegin` must be a valid pointer to a valid VkConditionalRenderingBeginInfoEXT structure

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute |

The `VkConditionalRenderingBeginInfoEXT` structure is defined as:

    typedef struct VkConditionalRenderingBeginInfoEXT {
        VkStructureType                   sType;
        const void*                       pNext;
        VkBuffer                          buffer;
        VkDeviceSize                      offset;
        VkConditionalRenderingFlagsEXT    flags;
    } VkConditionalRenderingBeginInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `buffer` is a buffer containing the predicate for conditional rendering.

- `offset` is the byte offset into `buffer` where the predicate is located.

- `flags` is a bitmask of VkConditionalRenderingFlagsEXT specifying the behavior of conditional rendering.

If the 32-bit value at `offset` in `buffer` memory is zero, then the rendering commands are discarded, otherwise they are executed as normal. If the value of the predicate in buffer memory changes while conditional rendering is active, the rendering commands may be discarded in an implementation-dependent way. Some implementations may latch the value of the predicate upon beginning conditional rendering while others may read it before every rendering command.

Valid Usage

- If `buffer` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `buffer` must have been created with the `VK_BUFFER_USAGE_CONDITIONAL_RENDERING_BIT_EXT` bit set

- `offset` must be less than the size of `buffer` by at least 32 bits.

- `offset` must be a multiple of 4

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_CONDITIONAL_RENDERING_BEGIN_INFO_EXT`

- `pNext` must be `NULL`

- `buffer` must be a valid VkBuffer handle

- `flags` must be a valid combination of VkConditionalRenderingFlagBitsEXT values

Bits which can be set in vkCmdBeginConditionalRenderingEXT::`flags` specifying the behavior of conditional rendering are:

    typedef enum VkConditionalRenderingFlagBitsEXT {
        VK_CONDITIONAL_RENDERING_INVERTED_BIT_EXT = 0x00000001,
        VK_CONDITIONAL_RENDERING_FLAG_BITS_MAX_ENUM_EXT = 0x7FFFFFFF
    } VkConditionalRenderingFlagBitsEXT;

- `VK_CONDITIONAL_RENDERING_INVERTED_BIT_EXT` specifies the condition used to determine whether to discard rendering commands or not. That is, if the 32-bit predicate read from `buffer` memory at `offset` is zero, the rendering commands are not discarded, and if non zero, then they are discarded.

    typedef VkFlags VkConditionalRenderingFlagsEXT;

`VkConditionalRenderingFlagsEXT` is a bitmask type for setting a mask of zero or more VkConditionalRenderingFlagBitsEXT.

To end conditional rendering, call:

    void vkCmdEndConditionalRenderingEXT(
        VkCommandBuffer                             commandBuffer);

- `commandBuffer` is the command buffer into which this command will be recorded.

Once ended, conditional rendering becomes inactive.

Valid Usage

- Conditional rendering must be active

- If conditional rendering was made active outside of a render pass instance, it must not be ended inside a render pass instance

- If conditional rendering was made active within a subpass it must be ended in the same subpass

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute |

### 20.5. Programmable Mesh Shading

In this drawing approach, primitives are assembled by the mesh shader stage. Mesh shading operates similarly to dispatching compute as the shaders make use of workgroups.

To record a draw that uses the mesh pipeline, call:

    void vkCmdDrawMeshTasksNV(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    taskCount,
        uint32_t                                    firstTask);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `taskCount` is the number of local workgroups to dispatch in the X dimension. Y and Z dimension are implicitly set to one.

- `firstTask` is the X component of the first workgroup ID.

When the command is executed, a global workgroup consisting of `taskCount` local workgroups is assembled.

Valid Usage

- If a `VkImageView` is sampled with `VK_FILTER_LINEAR` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT`

- If a `VkImageView` is accessed using atomic operations as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT`

- If a `VkImageView` is sampled with `VK_FILTER_CUBIC_EXT` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_EXT`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` as a result of this command must have a VkImageViewType and format that supports cubic filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubic` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` with a reduction mode of either `VK_SAMPLER_REDUCTION_MODE_MIN` or `VK_SAMPLER_REDUCTION_MODE_MAX` as a result of this command must have a VkImageViewType and format that supports cubic filtering together with minmax filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubicMinmax` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImage created with a VkImageCreateInfo::`flags` containing `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV` sampled as a result of this command must only be sampled using a VkSamplerAddressMode of `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`.

- For each set n that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a descriptor set must have been bound to n at the same pipeline bind point, with a `VkPipelineLayout` that is compatible for set n, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- For each push constant that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a push constant value must have been set for the same pipeline bind point, with a `VkPipelineLayout` that is compatible for push constants, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- Descriptors in each bound descriptor set, specified via `vkCmdBindDescriptorSets`, must be valid if they are statically used by the `VkPipeline` bound to the pipeline bind point used by this command

- A valid pipeline must be bound to the pipeline bind point used by this command

- If the `VkPipeline` object bound to the pipeline bind point used by this command requires any dynamic state, that state must have been set for `commandBuffer`, and done so after any previously bound pipeline with the corresponding state not specified as dynamic

- There must not have been any calls to dynamic state setting commands for any state not specified as dynamic in the `VkPipeline` object bound to the pipeline bind point used by this command, since that pipeline was bound

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used to sample from any `VkImage` with a `VkImageView` of the type `VK_IMAGE_VIEW_TYPE_3D`, `VK_IMAGE_VIEW_TYPE_CUBE`, `VK_IMAGE_VIEW_TYPE_1D_ARRAY`, `VK_IMAGE_VIEW_TYPE_2D_ARRAY` or `VK_IMAGE_VIEW_TYPE_CUBE_ARRAY`, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions with `ImplicitLod`, `Dref` or `Proj` in their name, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions that includes a LOD bias or any offset values, in any shader stage

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a uniform buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a storage buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If `commandBuffer` is an unprotected command buffer, any resource accessed by the `VkPipeline` object bound to the pipeline bind point used by this command must not be a protected resource

- The current render pass must be compatible with the `renderPass` member of the `VkGraphicsPipelineCreateInfo` structure specified when creating the `VkPipeline` bound to `VK_PIPELINE_BIND_POINT_GRAPHICS`.

- The subpass index of the current render pass must be equal to the `subpass` member of the `VkGraphicsPipelineCreateInfo` structure specified when creating the `VkPipeline` bound to `VK_PIPELINE_BIND_POINT_GRAPHICS`.

- Every input attachment used by the current subpass must be bound to the pipeline via a descriptor set

- Image subresources used as attachments in the current render pass must not be accessed in any way other than as an attachment by this command.

- If the draw is recorded in a render pass instance with multiview enabled, the maximum instance index must be less than or equal to VkPhysicalDeviceMultiviewProperties::`maxMultiviewInstanceIndex`.

- If the bound graphics pipeline was created with VkPipelineSampleLocationsStateCreateInfoEXT::`sampleLocationsEnable` set to `VK_TRUE` and the current subpass has a depth/stencil attachment, then that attachment must have been created with the `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT` bit set

- `taskCount` must be less than or equal to `VkPhysicalDeviceMeshShaderPropertiesNV`::`maxDrawMeshTasksCount`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- This command must only be called inside of a render pass instance

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Inside | Graphics | Graphics

To record an indirect mesh tasks draw, call:

    void vkCmdDrawMeshTasksIndirectNV(
        VkCommandBuffer                             commandBuffer,
        VkBuffer                                    buffer,
        VkDeviceSize                                offset,
        uint32_t                                    drawCount,
        uint32_t                                    stride);

- `commandBuffer` is the command buffer into which the command is recorded.

- `buffer` is the buffer containing draw parameters.

- `offset` is the byte offset into `buffer` where parameters begin.

- `drawCount` is the number of draws to execute, and can be zero.

- `stride` is the byte stride between successive sets of draw parameters.

`vkCmdDrawMeshTasksIndirectNV` behaves similarly to vkCmdDrawMeshTasksNV except that the parameters are read by the device from a buffer during execution. `drawCount` draws are executed by the command, with parameters taken from `buffer` starting at `offset` and increasing by `stride` bytes for each successive draw. The parameters of each draw are encoded in an array of VkDrawMeshTasksIndirectCommandNV structures. If `drawCount` is less than or equal to one, `stride` is ignored.

Valid Usage

- If a `VkImageView` is sampled with `VK_FILTER_LINEAR` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT`

- If a `VkImageView` is accessed using atomic operations as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT`

- If a `VkImageView` is sampled with `VK_FILTER_CUBIC_EXT` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_EXT`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` as a result of this command must have a VkImageViewType and format that supports cubic filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubic` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` with a reduction mode of either `VK_SAMPLER_REDUCTION_MODE_MIN` or `VK_SAMPLER_REDUCTION_MODE_MAX` as a result of this command must have a VkImageViewType and format that supports cubic filtering together with minmax filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubicMinmax` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImage created with a VkImageCreateInfo::`flags` containing `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV` sampled as a result of this command must only be sampled using a VkSamplerAddressMode of `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`.

- For each set n that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a descriptor set must have been bound to n at the same pipeline bind point, with a `VkPipelineLayout` that is compatible for set n, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- For each push constant that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a push constant value must have been set for the same pipeline bind point, with a `VkPipelineLayout` that is compatible for push constants, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- Descriptors in each bound descriptor set, specified via `vkCmdBindDescriptorSets`, must be valid if they are statically used by the `VkPipeline` bound to the pipeline bind point used by this command

- A valid pipeline must be bound to the pipeline bind point used by this command

- If the `VkPipeline` object bound to the pipeline bind point used by this command requires any dynamic state, that state must have been set for `commandBuffer`, and done so after any previously bound pipeline with the corresponding state not specified as dynamic

- There must not have been any calls to dynamic state setting commands for any state not specified as dynamic in the `VkPipeline` object bound to the pipeline bind point used by this command, since that pipeline was bound

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used to sample from any `VkImage` with a `VkImageView` of the type `VK_IMAGE_VIEW_TYPE_3D`, `VK_IMAGE_VIEW_TYPE_CUBE`, `VK_IMAGE_VIEW_TYPE_1D_ARRAY`, `VK_IMAGE_VIEW_TYPE_2D_ARRAY` or `VK_IMAGE_VIEW_TYPE_CUBE_ARRAY`, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions with `ImplicitLod`, `Dref` or `Proj` in their name, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions that includes a LOD bias or any offset values, in any shader stage

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a uniform buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a storage buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If `commandBuffer` is an unprotected command buffer, any resource accessed by the `VkPipeline` object bound to the pipeline bind point used by this command must not be a protected resource

- The current render pass must be compatible with the `renderPass` member of the `VkGraphicsPipelineCreateInfo` structure specified when creating the `VkPipeline` bound to `VK_PIPELINE_BIND_POINT_GRAPHICS`.

- The subpass index of the current render pass must be equal to the `subpass` member of the `VkGraphicsPipelineCreateInfo` structure specified when creating the `VkPipeline` bound to `VK_PIPELINE_BIND_POINT_GRAPHICS`.

- Every input attachment used by the current subpass must be bound to the pipeline via a descriptor set

- Image subresources used as attachments in the current render pass must not be accessed in any way other than as an attachment by this command.

- If the draw is recorded in a render pass instance with multiview enabled, the maximum instance index must be less than or equal to VkPhysicalDeviceMultiviewProperties::`maxMultiviewInstanceIndex`.

- If the bound graphics pipeline was created with VkPipelineSampleLocationsStateCreateInfoEXT::`sampleLocationsEnable` set to `VK_TRUE` and the current subpass has a depth/stencil attachment, then that attachment must have been created with the `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT` bit set

- If `buffer` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `buffer` must have been created with the `VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT` bit set

- `offset` must be a multiple of `4`

- `commandBuffer` must not be a protected command buffer

- If the multi-draw indirect feature is not enabled, `drawCount` must be `0` or `1`

- `drawCount` must be less than or equal to `VkPhysicalDeviceLimits`::`maxDrawIndirectCount`

- If `drawCount` is greater than `1`, `stride` must be a multiple of `4` and must be greater than or equal to `sizeof`(`VkDrawMeshTasksIndirectCommandNV`)

- If `drawCount` is equal to `1`, (`offset` + `sizeof`(VkDrawMeshTasksIndirectCommandNV)) must be less than or equal to the size of `buffer`

- If `drawCount` is greater than `1`, (`stride` × (`drawCount` - 1) + `offset` + `sizeof`(VkDrawMeshTasksIndirectCommandNV)) must be less than or equal to the size of `buffer`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `buffer` must be a valid VkBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- This command must only be called inside of a render pass instance

- Both of `buffer`, and `commandBuffer` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Inside | Graphics | Graphics

The `VkDrawMeshTasksIndirectCommandNV` structure is defined as:

    typedef struct VkDrawMeshTasksIndirectCommandNV {
        uint32_t    taskCount;
        uint32_t    firstTask;
    } VkDrawMeshTasksIndirectCommandNV;

- `taskCount` is the number of local workgroups to dispatch in the X dimension. Y and Z dimension are implicitly set to one.

- `firstTask` is the X component of the first workgroup ID.

The members of `VkDrawMeshTasksIndirectCommandNV` have the same meaning as the similarly named parameters of vkCmdDrawMeshTasksNV.

Valid Usage

- `taskCount` must be less than or equal to `VkPhysicalDeviceMeshShaderPropertiesNV`::`maxDrawMeshTasksCount`

To record an indirect mesh tasks draw with the draw count sourced from a buffer, call:

    void vkCmdDrawMeshTasksIndirectCountNV(
        VkCommandBuffer                             commandBuffer,
        VkBuffer                                    buffer,
        VkDeviceSize                                offset,
        VkBuffer                                    countBuffer,
        VkDeviceSize                                countBufferOffset,
        uint32_t                                    maxDrawCount,
        uint32_t                                    stride);

- `commandBuffer` is the command buffer into which the command is recorded.

- `buffer` is the buffer containing draw parameters.

- `offset` is the byte offset into `buffer` where parameters begin.

- `countBuffer` is the buffer containing the draw count.

- `countBufferOffset` is the byte offset into `countBuffer` where the draw count begins.

- `maxDrawCount` specifies the maximum number of draws that will be executed. The actual number of executed draw calls is the minimum of the count specified in `countBuffer` and `maxDrawCount`.

- `stride` is the byte stride between successive sets of draw parameters.

`vkCmdDrawMeshTasksIndirectCountNV` behaves similarly to vkCmdDrawMeshTasksIndirectNV except that the draw count is read by the device from a buffer during execution. The command will read an unsigned 32-bit integer from `countBuffer` located at `countBufferOffset` and use this as the draw count.

Valid Usage

- If a `VkImageView` is sampled with `VK_FILTER_LINEAR` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT`

- If a `VkImageView` is accessed using atomic operations as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT`

- If a `VkImageView` is sampled with `VK_FILTER_CUBIC_EXT` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_EXT`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` as a result of this command must have a VkImageViewType and format that supports cubic filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubic` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` with a reduction mode of either `VK_SAMPLER_REDUCTION_MODE_MIN` or `VK_SAMPLER_REDUCTION_MODE_MAX` as a result of this command must have a VkImageViewType and format that supports cubic filtering together with minmax filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubicMinmax` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImage created with a VkImageCreateInfo::`flags` containing `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV` sampled as a result of this command must only be sampled using a VkSamplerAddressMode of `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`.

- For each set n that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a descriptor set must have been bound to n at the same pipeline bind point, with a `VkPipelineLayout` that is compatible for set n, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- For each push constant that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a push constant value must have been set for the same pipeline bind point, with a `VkPipelineLayout` that is compatible for push constants, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- Descriptors in each bound descriptor set, specified via `vkCmdBindDescriptorSets`, must be valid if they are statically used by the `VkPipeline` bound to the pipeline bind point used by this command

- A valid pipeline must be bound to the pipeline bind point used by this command

- If the `VkPipeline` object bound to the pipeline bind point used by this command requires any dynamic state, that state must have been set for `commandBuffer`, and done so after any previously bound pipeline with the corresponding state not specified as dynamic

- There must not have been any calls to dynamic state setting commands for any state not specified as dynamic in the `VkPipeline` object bound to the pipeline bind point used by this command, since that pipeline was bound

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used to sample from any `VkImage` with a `VkImageView` of the type `VK_IMAGE_VIEW_TYPE_3D`, `VK_IMAGE_VIEW_TYPE_CUBE`, `VK_IMAGE_VIEW_TYPE_1D_ARRAY`, `VK_IMAGE_VIEW_TYPE_2D_ARRAY` or `VK_IMAGE_VIEW_TYPE_CUBE_ARRAY`, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions with `ImplicitLod`, `Dref` or `Proj` in their name, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions that includes a LOD bias or any offset values, in any shader stage

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a uniform buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a storage buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If `commandBuffer` is an unprotected command buffer, any resource accessed by the `VkPipeline` object bound to the pipeline bind point used by this command must not be a protected resource

- The current render pass must be compatible with the `renderPass` member of the `VkGraphicsPipelineCreateInfo` structure specified when creating the `VkPipeline` bound to `VK_PIPELINE_BIND_POINT_GRAPHICS`.

- The subpass index of the current render pass must be equal to the `subpass` member of the `VkGraphicsPipelineCreateInfo` structure specified when creating the `VkPipeline` bound to `VK_PIPELINE_BIND_POINT_GRAPHICS`.

- Every input attachment used by the current subpass must be bound to the pipeline via a descriptor set

- Image subresources used as attachments in the current render pass must not be accessed in any way other than as an attachment by this command.

- If the draw is recorded in a render pass instance with multiview enabled, the maximum instance index must be less than or equal to VkPhysicalDeviceMultiviewProperties::`maxMultiviewInstanceIndex`.

- If the bound graphics pipeline was created with VkPipelineSampleLocationsStateCreateInfoEXT::`sampleLocationsEnable` set to `VK_TRUE` and the current subpass has a depth/stencil attachment, then that attachment must have been created with the `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT` bit set

- If `buffer` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `buffer` must have been created with the `VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT` bit set

- `offset` must be a multiple of `4`

- `commandBuffer` must not be a protected command buffer

- If `countBuffer` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `countBuffer` must have been created with the `VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT` bit set

- `countBufferOffset` must be a multiple of `4`

- The count stored in `countBuffer` must be less than or equal to `VkPhysicalDeviceLimits`::`maxDrawIndirectCount`

- `stride` must be a multiple of `4` and must be greater than or equal to `sizeof`(`VkDrawMeshTasksIndirectCommandNV`)

- If `maxDrawCount` is greater than or equal to `1`, (`stride` × (`maxDrawCount` - 1) + `offset` + `sizeof`(`VkDrawMeshTasksIndirectCommandNV`)) must be less than or equal to the size of `buffer`

- If the count stored in `countBuffer` is equal to `1`, (`offset` + `sizeof`(`VkDrawMeshTasksIndirectCommandNV`)) must be less than or equal to the size of `buffer`

- If the count stored in `countBuffer` is greater than `1`, (`stride` × (`drawCount` - 1) + `offset` + `sizeof`(`VkDrawMeshTasksIndirectCommandNV`)) must be less than or equal to the size of `buffer`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `buffer` must be a valid VkBuffer handle

- `countBuffer` must be a valid VkBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- This command must only be called inside of a render pass instance

- Each of `buffer`, `commandBuffer`, and `countBuffer` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Inside | Graphics | Graphics

## 21. Fixed-Function Vertex Processing

Vertex fetching is controlled via configurable state, as a logically distinct graphics pipeline stage.

### 21.1. Vertex Attributes

Vertex shaders can define input variables, which receive vertex attribute data transferred from one or more `VkBuffer`(s) by drawing commands. Vertex shader input variables are bound to buffers via an indirect binding where the vertex shader associates a vertex input attribute number with each variable, vertex input attributes are associated to vertex input bindings on a per-pipeline basis, and vertex input bindings are associated with specific buffers on a per-draw basis via the `vkCmdBindVertexBuffers` command. Vertex input attribute and vertex input binding descriptions also contain format information controlling how data is extracted from buffer memory and converted to the format expected by the vertex shader.

There are `VkPhysicalDeviceLimits`::`maxVertexInputAttributes` number of vertex input attributes and `VkPhysicalDeviceLimits`::`maxVertexInputBindings` number of vertex input bindings (each referred to by zero-based indices), where there are at least as many vertex input attributes as there are vertex input bindings. Applications can store multiple vertex input attributes interleaved in a single buffer, and use a single vertex input binding to access those attributes.

In GLSL, vertex shaders associate input variables with a vertex input attribute number using the `location` layout qualifier. The `component` layout qualifier associates components of a vertex shader input variable with components of a vertex input attribute.

GLSL example

    // Assign location M to variableName
    layout (location=M, component=2) in vec2 variableName;

    // Assign locations [N,N+L) to the array elements of variableNameArray
    layout (location=N) in vec4 variableNameArray[L];

In SPIR-V, vertex shaders associate input variables with a vertex input attribute number using the `Location` decoration. The `Component` decoration associates components of a vertex shader input variable with components of a vertex input attribute. The `Location` and `Component` decorations are specified via the `OpDecorate` instruction.

SPIR-V example

                   ...
              %1 = OpExtInstImport "GLSL.std.450"
                   ...
                   OpName %9 "variableName"
                   OpName %15 "variableNameArray"
                   OpDecorate %18 BuiltIn VertexIndex
                   OpDecorate %19 BuiltIn InstanceIndex
                   OpDecorate %9 Location M
                   OpDecorate %9 Component 2
                   OpDecorate %15 Location N
                   ...
              %2 = OpTypeVoid
              %3 = OpTypeFunction %2
              %6 = OpTypeFloat 32
              %7 = OpTypeVector %6 2
              %8 = OpTypePointer Input %7
              %9 = OpVariable %8 Input
             %10 = OpTypeVector %6 4
             %11 = OpTypeInt 32 0
             %12 = OpConstant %11 L
             %13 = OpTypeArray %10 %12
             %14 = OpTypePointer Input %13
             %15 = OpVariable %14 Input
                   ...

#### 21.1.1. Attribute Location and Component Assignment

Vertex shaders allow `Location` and `Component` decorations on input variable declarations. The `Location` decoration specifies which vertex input attribute is used to read and interpret the data that a variable will consume. The `Component` decoration allows the location to be more finely specified for scalars and vectors, down to the individual components within a location that are consumed. The components within a location are 0, 1, 2, and 3. A variable starting at component N will consume components N, N+1, N+2, …​ up through its size. For single precision types, it is invalid if the sequence of components gets larger than 3.

When a vertex shader input variable declared using a scalar or vector 32-bit data type is assigned a location, its value(s) are taken from the components of the input attribute specified with the corresponding `VkVertexInputAttributeDescription`::`location`. The components used depend on the type of variable and the `Component` decoration specified in the variable declaration, as identified in Input attribute components accessed by 32-bit input variables. Any 32-bit scalar or vector input will consume a single location. For 32-bit data types, missing components are filled in with default values as described below.

Table 28. Input attribute components accessed by 32-bit input variables
32-bit data type | `Component` decoration | Components consumed
--- | --- | ---
scalar | 0 or unspecified | (x, o, o, o)
scalar | 1 | (o, y, o, o)
scalar | 2 | (o, o, z, o)
scalar | 3 | (o, o, o, w)
two-component vector | 0 or unspecified | (x, y, o, o)
two-component vector | 1 | (o, y, z, o)
two-component vector | 2 | (o, o, z, w)
three-component vector | 0 or unspecified | (x, y, z, o)
three-component vector | 1 | (o, y, z, w)
four-component vector | 0 or unspecified | (x, y, z, w)

Components indicated by “o” are available for use by other input variables which are sourced from the same attribute, and if used, are either filled with the corresponding component from the input format (if present), or the default value.

When a vertex shader input variable declared using a 32-bit floating point matrix type is assigned a location i, its values are taken from consecutive input attributes starting with the corresponding `VkVertexInputAttributeDescription`::`location`. Such matrices are treated as an array of column vectors with values taken from the input attributes identified in Input attributes accessed by 32-bit input matrix variables. The `VkVertexInputAttributeDescription`::`format` must be specified with a VkFormat that corresponds to the appropriate type of column vector. The `Component` decoration must not be used with matrix types.

Table 29. Input attributes accessed by 32-bit input matrix variables
Data type | Column vector type | Locations consumed | Components consumed
--- | --- | --- | ---
mat2 | two-component vector | i, i+1 | (x, y, o, o), (x, y, o, o)
mat2x3 | three-component vector | i, i+1 | (x, y, z, o), (x, y, z, o)
mat2x4 | four-component vector | i, i+1 | (x, y, z, w), (x, y, z, w)
mat3x2 | two-component vector | i, i+1, i+2 | (x, y, o, o), (x, y, o, o), (x, y, o, o)
mat3 | three-component vector | i, i+1, i+2 | (x, y, z, o), (x, y, z, o), (x, y, z, o)
mat3x4 | four-component vector | i, i+1, i+2 | (x, y, z, w), (x, y, z, w), (x, y, z, w)
mat4x2 | two-component vector | i, i+1, i+2, i+3 | (x, y, o, o), (x, y, o, o), (x, y, o, o), (x, y, o, o)
mat4x3 | three-component vector | i, i+1, i+2, i+3 | (x, y, z, o), (x, y, z, o), (x, y, z, o), (x, y, z, o)
mat4 | four-component vector | i, i+1, i+2, i+3 | (x, y, z, w), (x, y, z, w), (x, y, z, w), (x, y, z, w)

Components indicated by “o” are available for use by other input variables which are sourced from the same attribute, and if used, are either filled with the corresponding component from the input (if present), or the default value.

When a vertex shader input variable declared using a scalar or vector 64-bit data type is assigned a location i, its values are taken from consecutive input attributes starting with the corresponding `VkVertexInputAttributeDescription`::`location`. The locations and components used depend on the type of variable and the `Component` decoration specified in the variable declaration, as identified in Input attribute locations and components accessed by 64-bit input variables. For 64-bit data types, no default attribute values are provided. Input variables must not use more components than provided by the attribute. Input attributes which have one- or two-component 64-bit formats will consume a single location. Input attributes which have three- or four-component 64-bit formats will consume two consecutive locations. A 64-bit scalar data type will consume two components, and a 64-bit two-component vector data type will consume all four components available within a location. A three- or four-component 64-bit data type must not specify a component. A three-component 64-bit data type will consume all four components of the first location and components 0 and 1 of the second location. This leaves components 2 and 3 available for other component-qualified declarations. A four-component 64-bit data type will consume all four components of the first location and all four components of the second location. It is invalid for a scalar or two-component 64-bit data type to specify a component of 1 or 3.

Table 30. Input attribute locations and components accessed by 64-bit input variables
Input format | Locations consumed | 64-bit data type | `Location` decoration | `Component` decoration | 32-bit components consumed
--- | --- | --- | --- | --- | ---
R64 | i | scalar | i | 0 or unspecified | (x, y, -, -)
R64G64 | i | scalar | i | 0 or unspecified | (x, y, o, o)
scalar | i | 2 | (o, o, z, w)
two-component vector | i | 0 or unspecified | (x, y, z, w)
R64G64B64 | i, i+1 | scalar | i | 0 or unspecified | (x, y, o, o), (o, o, -, -)
scalar | i | 2 | (o, o, z, w), (o, o, -, -)
scalar | i+1 | 0 or unspecified | (o, o, o, o), (x, y, -, -)
two-component vector | i | 0 or unspecified | (x, y, z, w), (o, o, -, -)
three-component vector | i | unspecified | (x, y, z, w), (x, y, -, -)
R64G64B64A64 | i, i+1 | scalar | i | 0 or unspecified | (x, y, o, o), (o, o, o, o)
scalar | i | 2 | (o, o, z, w), (o, o, o, o)
scalar | i+1 | 0 or unspecified | (o, o, o, o), (x, y, o, o)
scalar | i+1 | 2 | (o, o, o, o), (o, o, z, w)
two-component vector | i | 0 or unspecified | (x, y, z, w), (o, o, o, o)
two-component vector | i+1 | 0 or unspecified | (o, o, o, o), (x, y, z, w)
three-component vector | i | unspecified | (x, y, z, w), (x, y, o, o)
four-component vector | i | unspecified | (x, y, z, w), (x, y, z, w)

Components indicated by “o” are available for use by other input variables which are sourced from the same attribute. Components indicated by “-” are not available for input variables as there are no default values provided for 64-bit data types, and there is no data provided by the input format.

When a vertex shader input variable declared using a 64-bit floating-point matrix type is assigned a location i, its values are taken from consecutive input attribute locations. Such matrices are treated as an array of column vectors with values taken from the input attributes as shown in Input attribute locations and components accessed by 64-bit input variables. Each column vector starts at the location immediately following the last location of the previous column vector. The number of attributes and components assigned to each matrix is determined by the matrix dimensions and ranges from two to eight locations.

When a vertex shader input variable declared using an array type is assigned a location, its values are taken from consecutive input attributes starting with the corresponding `VkVertexInputAttributeDescription`::`location`. The number of attributes and components assigned to each element are determined according to the data type of the array elements and `Component` decoration (if any) specified in the declaration of the array, as described above. Each element of the array, in order, is assigned to consecutive locations, but all at the same specified component within each location.

Only input variables declared with the data types and component decorations as specified above are supported. Location aliasing is causing two variables to have the same location number. Component aliasing is assigning the same (or overlapping) component number for two location aliases. Location aliasing is allowed only if it does not cause component aliasing. Further, when location aliasing, the aliases sharing the location must all have the same SPIR-V floating-point component type or all have the same width integer-type components.

### 21.2. Vertex Input Description

Applications specify vertex input attribute and vertex input binding descriptions as part of graphics pipeline creation. VkGraphicsPipelineCreateInfo::`pVertexInputState` is a pointer to a VkPipelineVertexInputStateCreateInfo value.

The `VkPipelineVertexInputStateCreateInfo` structure is defined as:

    typedef struct VkPipelineVertexInputStateCreateInfo {
        VkStructureType                             sType;
        const void*                                 pNext;
        VkPipelineVertexInputStateCreateFlags       flags;
        uint32_t                                    vertexBindingDescriptionCount;
        const VkVertexInputBindingDescription*      pVertexBindingDescriptions;
        uint32_t                                    vertexAttributeDescriptionCount;
        const VkVertexInputAttributeDescription*    pVertexAttributeDescriptions;
    } VkPipelineVertexInputStateCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `vertexBindingDescriptionCount` is the number of vertex binding descriptions provided in `pVertexBindingDescriptions`.

- `pVertexBindingDescriptions` is a pointer to an array of `VkVertexInputBindingDescription` structures.

- `vertexAttributeDescriptionCount` is the number of vertex attribute descriptions provided in `pVertexAttributeDescriptions`.

- `pVertexAttributeDescriptions` is a pointer to an array of `VkVertexInputAttributeDescription` structures.

Valid Usage

- `vertexBindingDescriptionCount` must be less than or equal to `VkPhysicalDeviceLimits`::`maxVertexInputBindings`

- `vertexAttributeDescriptionCount` must be less than or equal to `VkPhysicalDeviceLimits`::`maxVertexInputAttributes`

- For every `binding` specified by each element of `pVertexAttributeDescriptions`, a `VkVertexInputBindingDescription` must exist in `pVertexBindingDescriptions` with the same value of `binding`

- All elements of `pVertexBindingDescriptions` must describe distinct binding numbers

- All elements of `pVertexAttributeDescriptions` must describe distinct attribute locations

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_STATE_CREATE_INFO`

- `pNext` must be `NULL` or a pointer to a valid instance of VkPipelineVertexInputDivisorStateCreateInfoEXT

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be `0`

- If `vertexBindingDescriptionCount` is not `0`, `pVertexBindingDescriptions` must be a valid pointer to an array of `vertexBindingDescriptionCount` valid VkVertexInputBindingDescription structures

- If `vertexAttributeDescriptionCount` is not `0`, `pVertexAttributeDescriptions` must be a valid pointer to an array of `vertexAttributeDescriptionCount` valid VkVertexInputAttributeDescription structures

    typedef VkFlags VkPipelineVertexInputStateCreateFlags;

`VkPipelineVertexInputStateCreateFlags` is a bitmask type for setting a mask, but is currently reserved for future use.

Each vertex input binding is specified by the `VkVertexInputBindingDescription` structure, defined as:

    typedef struct VkVertexInputBindingDescription {
        uint32_t             binding;
        uint32_t             stride;
        VkVertexInputRate    inputRate;
    } VkVertexInputBindingDescription;

- `binding` is the binding number that this structure describes.

- `stride` is the distance in bytes between two consecutive elements within the buffer.

- `inputRate` is a VkVertexInputRate value specifying whether vertex attribute addressing is a function of the vertex index or of the instance index.

Valid Usage

- `binding` must be less than `VkPhysicalDeviceLimits`::`maxVertexInputBindings`

- `stride` must be less than or equal to `VkPhysicalDeviceLimits`::`maxVertexInputBindingStride`

Valid Usage (Implicit)

- `inputRate` must be a valid VkVertexInputRate value

Possible values of VkVertexInputBindingDescription::`inputRate`, specifying the rate at which vertex attributes are pulled from buffers, are:

    typedef enum VkVertexInputRate {
        VK_VERTEX_INPUT_RATE_VERTEX = 0,
        VK_VERTEX_INPUT_RATE_INSTANCE = 1,
        VK_VERTEX_INPUT_RATE_MAX_ENUM = 0x7FFFFFFF
    } VkVertexInputRate;

- `VK_VERTEX_INPUT_RATE_VERTEX` specifies that vertex attribute addressing is a function of the vertex index.

- `VK_VERTEX_INPUT_RATE_INSTANCE` specifies that vertex attribute addressing is a function of the instance index.

Each vertex input attribute is specified by the `VkVertexInputAttributeDescription` structure, defined as:

    typedef struct VkVertexInputAttributeDescription {
        uint32_t    location;
        uint32_t    binding;
        VkFormat    format;
        uint32_t    offset;
    } VkVertexInputAttributeDescription;

- `location` is the shader binding location number for this attribute.

- `binding` is the binding number which this attribute takes its data from.

- `format` is the size and type of the vertex attribute data.

- `offset` is a byte offset of this attribute relative to the start of an element in the vertex input binding.

Valid Usage

- `location` must be less than `VkPhysicalDeviceLimits`::`maxVertexInputAttributes`

- `binding` must be less than `VkPhysicalDeviceLimits`::`maxVertexInputBindings`

- `offset` must be less than or equal to `VkPhysicalDeviceLimits`::`maxVertexInputAttributeOffset`

- `format` must be allowed as a vertex buffer format, as specified by the `VK_FORMAT_FEATURE_VERTEX_BUFFER_BIT` flag in `VkFormatProperties`::`bufferFeatures` returned by `vkGetPhysicalDeviceFormatProperties`

Valid Usage (Implicit)

- `format` must be a valid VkFormat value

To bind vertex buffers to a command buffer for use in subsequent draw commands, call:

    void vkCmdBindVertexBuffers(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    firstBinding,
        uint32_t                                    bindingCount,
        const VkBuffer*                             pBuffers,
        const VkDeviceSize*                         pOffsets);

- `commandBuffer` is the command buffer into which the command is recorded.

- `firstBinding` is the index of the first vertex input binding whose state is updated by the command.

- `bindingCount` is the number of vertex input bindings whose state is updated by the command.

- `pBuffers` is a pointer to an array of buffer handles.

- `pOffsets` is a pointer to an array of buffer offsets.

The values taken from elements i of `pBuffers` and `pOffsets` replace the current state for the vertex input binding `firstBinding` + i, for i in [0, `bindingCount`). The vertex input binding is updated to start at the offset indicated by `pOffsets`[i] from the start of the buffer `pBuffers`[i]. All vertex input attributes that use each of these bindings will use these updated addresses in their address calculations for subsequent draw commands.

Valid Usage

- `firstBinding` must be less than `VkPhysicalDeviceLimits`::`maxVertexInputBindings`

- The sum of `firstBinding` and `bindingCount` must be less than or equal to `VkPhysicalDeviceLimits`::`maxVertexInputBindings`

- All elements of `pOffsets` must be less than the size of the corresponding element in `pBuffers`

- All elements of `pBuffers` must have been created with the `VK_BUFFER_USAGE_VERTEX_BUFFER_BIT` flag

- Each element of `pBuffers` that is non-sparse must be bound completely and contiguously to a single `VkDeviceMemory` object

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pBuffers` must be a valid pointer to an array of `bindingCount` valid VkBuffer handles

- `pOffsets` must be a valid pointer to an array of `bindingCount` `VkDeviceSize` values

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- `bindingCount` must be greater than `0`

- Both of `commandBuffer`, and the elements of `pBuffers` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics |

### 21.3. Vertex Attribute Divisor in Instanced Rendering

If `vertexAttributeInstanceRateDivisor` feature is enabled and the `pNext` chain of VkPipelineVertexInputStateCreateInfo includes a `VkPipelineVertexInputDivisorStateCreateInfoEXT` structure, then that structure controls how vertex attributes are assigned to an instance when instanced rendering is enabled.

The `VkPipelineVertexInputDivisorStateCreateInfoEXT` structure is defined as:

    typedef struct VkPipelineVertexInputDivisorStateCreateInfoEXT {
        VkStructureType                                     sType;
        const void*                                         pNext;
        uint32_t                                            vertexBindingDivisorCount;
        const VkVertexInputBindingDivisorDescriptionEXT*    pVertexBindingDivisors;
    } VkPipelineVertexInputDivisorStateCreateInfoEXT;

- `sType` is the type of this structure

- `pNext` is `NULL` or a pointer to an extension-specific structure

- `vertexBindingDivisorCount` is the number of elements in the `pVertexBindingDivisors` array.

- `pVertexBindingDivisors` is a pointer to an array of `VkVertexInputBindingDivisorDescriptionEXT` structures, which specifies the divisor value for each binding.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_DIVISOR_STATE_CREATE_INFO_EXT`

- `pVertexBindingDivisors` must be a valid pointer to an array of `vertexBindingDivisorCount` VkVertexInputBindingDivisorDescriptionEXT structures

- `vertexBindingDivisorCount` must be greater than `0`

The individual divisor values per binding are specified using the `VkVertexInputBindingDivisorDescriptionEXT` structure which is defined as:

    typedef struct VkVertexInputBindingDivisorDescriptionEXT {
        uint32_t    binding;
        uint32_t    divisor;
    } VkVertexInputBindingDivisorDescriptionEXT;

- `binding` is the binding number for which the divisor is specified.

- `divisor` is the number of successive instances that will use the same value of the vertex attribute when instanced rendering is enabled. For example, if the divisor is N, the same vertex attribute will be applied to N successive instances before moving on to the next vertex attribute. The maximum value of divisor is implementation dependent and can be queried using `VkPhysicalDeviceVertexAttributeDivisorPropertiesEXT`::`maxVertexAttribDivisor`. A value of `0` can be used for the divisor if the `vertexAttributeInstanceRateZeroDivisor` feature is enabled. In this case, the same vertex attribute will be applied to all instances.

If this structure is not used to define a divisor value for an attribute then the divisor has a logical default value of 1.

Valid Usage

- `binding` must be less than `VkPhysicalDeviceLimits`::`maxVertexInputBindings`

- If the `vertexAttributeInstanceRateZeroDivisor` feature is not enabled, `divisor` must not be `0`

- If the `vertexAttributeInstanceRateDivisor` feature is not enabled, `divisor` must be `1`

- `divisor` must be a value between `0` and `VkPhysicalDeviceVertexAttributeDivisorPropertiesEXT`::`maxVertexAttribDivisor`, inclusive.

- VkVertexInputBindingDescription::`inputRate` must be of type `VK_VERTEX_INPUT_RATE_INSTANCE` for this `binding`.

The address of each attribute for each `vertexIndex` and `instanceIndex` is calculated as follows:

- Let `attribDesc` be the member of `VkPipelineVertexInputStateCreateInfo`::`pVertexAttributeDescriptions` with `VkVertexInputAttributeDescription`::`location` equal to the vertex input attribute number.

- Let `bindingDesc` be the member of `VkPipelineVertexInputStateCreateInfo`::`pVertexBindingDescriptions` with `VkVertexInputAttributeDescription`::`binding` equal to `attribDesc.binding`.

- Let `vertexIndex` be the index of the vertex within the draw (a value between `firstVertex` and `firstVertex`+`vertexCount` for `vkCmdDraw`, or a value taken from the index buffer for `vkCmdDrawIndexed`), and let `instanceIndex` be the instance number of the draw (a value between `firstInstance` and `firstInstance`+`instanceCount`).

- Let `divisor` be the member of `VkPipelineVertexInputDivisorStateCreateInfoEXT`::`pVertexBindingDivisors` with `VkVertexInputBindingDivisorDescriptionEXT`::`binding` equal to `attribDesc.binding`.

    bufferBindingAddress = buffer[binding].baseAddress + offset[binding];

    if (bindingDesc.inputRate == VK_VERTEX_INPUT_RATE_VERTEX)
        vertexOffset = vertexIndex * bindingDesc.stride;
    else
        if (divisor == 0)
            vertexOffset = firstInstance * bindingDesc.stride;
        else
            vertexOffset = (firstInstance + ((instanceIndex - firstInstance) / divisor)) * bindingDesc.stride;

    attribAddress = bufferBindingAddress + vertexOffset + attribDesc.offset;

For each attribute, raw data is extracted starting at `attribAddress` and is converted from the `VkVertexInputAttributeDescription`’s `format` to either floating-point, unsigned integer, or signed integer based on the base type of the format; the base type of the format must match the base type of the input variable in the shader. If `format` is a packed format, `attribAddress` must be a multiple of the size in bytes of the whole attribute data type as described in Packed Formats. Otherwise, `attribAddress` must be a multiple of the size in bytes of the component type indicated by `format` (see Formats). If the format does not include G, B, or A components, then those are filled with (0,0,1) as needed (using either 1.0f or integer 1 based on the format) for attributes that are not 64-bit data types. The number of components in the vertex shader input variable need not exactly match the number of components in the format. If the vertex shader has fewer components, the extra components are discarded.

### 21.4. Example

To create a graphics pipeline that uses the following vertex description:

    struct Vertex
    {
        float   x, y, z, w;
        uint8_t u, v;
    };

The application could use the following set of structures:

    const VkVertexInputBindingDescription binding =
    {
        0,                                          // binding
        sizeof(Vertex),                             // stride
        VK_VERTEX_INPUT_RATE_VERTEX                 // inputRate
    };

    const VkVertexInputAttributeDescription attributes[] =
    {
        {
            0,                                      // location
            binding.binding,                        // binding
            VK_FORMAT_R32G32B32A32_SFLOAT,          // format
            0                                       // offset
        },
        {
            1,                                      // location
            binding.binding,                        // binding
            VK_FORMAT_R8G8_UNORM,                   // format
            4 * sizeof(float)                       // offset
        }
    };

    const VkPipelineVertexInputStateCreateInfo viInfo =
    {
        VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_CREATE_INFO,    // sType
        NULL,                         // pNext
        0,                            // flags
        1,                            // vertexBindingDescriptionCount
        &binding,                     // pVertexBindingDescriptions
        2,                            // vertexAttributeDescriptionCount
        &attributes[0]                // pVertexAttributeDescriptions
    };

## 22. Tessellation

Tessellation involves three pipeline stages. First, a tessellation control shader transforms control points of a patch and can produce per-patch data. Second, a fixed-function tessellator generates multiple primitives corresponding to a tessellation of the patch in (u,v) or (u,v,w) parameter space. Third, a tessellation evaluation shader transforms the vertices of the tessellated patch, for example to compute their positions and attributes as part of the tessellated surface. The tessellator is enabled when the pipeline contains both a tessellation control shader and a tessellation evaluation shader.

### 22.1. Tessellator

If a pipeline includes both tessellation shaders (control and evaluation), the tessellator consumes each input patch (after vertex shading) and produces a new set of independent primitives (points, lines, or triangles). These primitives are logically produced by subdividing a geometric primitive (rectangle or triangle) according to the per-patch outer and inner tessellation levels written by the tessellation control shader. These levels are specified using the built-in variables `TessLevelOuter` and `TessLevelInner`, respectively. This subdivision is performed in an implementation-dependent manner. If no tessellation shaders are present in the pipeline, the tessellator is disabled and incoming primitives are passed through without modification.

The type of subdivision performed by the tessellator is specified by an `OpExecutionMode` instruction in the tessellation evaluation or tessellation control shader using one of execution modes `Triangles`, `Quads`, and `IsoLines`. Other tessellation-related execution modes can also be specified in either the tessellation control or tessellation evaluation shaders, and if they are specified in both then the modes must be the same.

Tessellation execution modes include:

- `Triangles`, `Quads`, and `IsoLines`. These control the type of subdivision and topology of the output primitives. One mode must be set in at least one of the tessellation shader stages.

- `VertexOrderCw` and `VertexOrderCcw`. These control the orientation of triangles generated by the tessellator. One mode must be set in at least one of the tessellation shader stages.

- `PointMode`. Controls generation of points rather than triangles or lines. This functionality defaults to disabled, and is enabled if either shader stage includes the execution mode.

- `SpacingEqual`, `SpacingFractionalEven`, and `SpacingFractionalOdd`. Controls the spacing of segments on the edges of tessellated primitives. One mode must be set in at least one of the tessellation shader stages.

- `OutputVertices`. Controls the size of the output patch of the tessellation control shader. One value must be set in at least one of the tessellation shader stages.

For triangles, the tessellator subdivides a triangle primitive into smaller triangles. For quads, the tessellator subdivides a rectangle primitive into smaller triangles. For isolines, the tessellator subdivides a rectangle primitive into a collection of line segments arranged in strips stretching across the rectangle in the u dimension (i.e. the coordinates in `TessCoord` are of the form (0,x) through (1,x) for all tessellation evaluation shader invocations that share a line).

Each vertex produced by the tessellator has an associated (u,v,w) or (u,v) position in a normalized parameter space, with parameter values in the range [0,1], as illustrated in figures Domain parameterization for tessellation primitive modes (upper-left origin) and Domain parameterization for tessellation primitive modes (lower-left origin). The domain space can have either an upper-left or lower-left origin, selected by the `domainOrigin` member of VkPipelineTessellationDomainOriginStateCreateInfo.

Figure 12. Domain parameterization for tessellation primitive modes (upper-left origin)
Figure 13. Domain parameterization for tessellation primitive modes (lower-left origin)
Caption

In the domain parameterization diagrams, the coordinates illustrate the value of `TessCoord` at the corners of the domain. The labels on the edges indicate the inner (IL0 and IL1) and outer (OL0 through OL3) tessellation level values used to control the number of subdivisions along each edge of the domain.

For triangles, the vertex’s position is a barycentric coordinate (u,v,w), where u + v + w = 1.0, and indicates the relative influence of the three vertices of the triangle on the position of the vertex. For quads and isolines, the position is a (u,v) coordinate indicating the relative horizontal and vertical position of the vertex relative to the subdivided rectangle. The subdivision process is explained in more detail in subsequent sections.

### 22.2. Tessellator Patch Discard

A patch is discarded by the tessellator if any relevant outer tessellation level is less than or equal to zero.

Patches will also be discarded if any relevant outer tessellation level corresponds to a floating-point NaN (not a number) in implementations supporting NaN.

No new primitives are generated and the tessellation evaluation shader is not executed for patches that are discarded. For `Quads`, all four outer levels are relevant. For `Triangles` and `IsoLines`, only the first three or two outer levels, respectively, are relevant. Negative inner levels will not cause a patch to be discarded; they will be clamped as described below.

### 22.3. Tessellator Spacing

Each of the tessellation levels is used to determine the number and spacing of segments used to subdivide a corresponding edge. The method used to derive the number and spacing of segments is specified by an `OpExecutionMode` in the tessellation control or tessellation evaluation shader using one of the identifiers `SpacingEqual`, `SpacingFractionalEven`, or `SpacingFractionalOdd`.

If `SpacingEqual` is used, the floating-point tessellation level is first clamped to [1, `maxLevel`], where `maxLevel` is the implementation-dependent maximum tessellation level (`VkPhysicalDeviceLimits`::`maxTessellationGenerationLevel`). The result is rounded up to the nearest integer n, and the corresponding edge is divided into n segments of equal length in (u,v) space.

If `SpacingFractionalEven` is used, the tessellation level is first clamped to [2, `maxLevel`] and then rounded up to the nearest even integer n. If `SpacingFractionalOdd` is used, the tessellation level is clamped to [1, `maxLevel` - 1] and then rounded up to the nearest odd integer n. If n is one, the edge will not be subdivided. Otherwise, the corresponding edge will be divided into n - 2 segments of equal length, and two additional segments of equal length that are typically shorter than the other segments. The length of the two additional segments relative to the others will decrease monotonically with n - f, where f is the clamped floating-point tessellation level. When n - f is zero, the additional segments will have equal length to the other segments. As n - f approaches 2.0, the relative length of the additional segments approaches zero. The two additional segments must be placed symmetrically on opposite sides of the subdivided edge. The relative location of these two segments is implementation-dependent, but must be identical for any pair of subdivided edges with identical values of f.

When tessellating triangles or quads using point mode with fractional odd spacing, the tessellator may produce interior vertices that are positioned on the edge of the patch if an inner tessellation level is less than or equal to one. Such vertices are considered distinct from vertices produced by subdividing the outer edge of the patch, even if there are pairs of vertices with identical coordinates.

### 22.4. Tessellation Primitive Ordering

Few guarantees are provided for the relative ordering of primitives produced by tessellation, as they pertain to primitive order.

- The output primitives generated from each input primitive are passed to subsequent pipeline stages in an implementation-dependent order.

- All output primitives generated from a given input primitive are passed to subsequent pipeline stages before any output primitives generated from subsequent input primitives.

### 22.5. Tessellator Vertex Winding Order

When the tessellator produces triangles (in the `Triangles` or `Quads` modes), the orientation of all triangles is specified with an `OpExecutionMode` of `VertexOrderCw` or `VertexOrderCcw` in the tessellation control or tessellation evaluation shaders. If the order is `VertexOrderCw`, the vertices of all generated triangles will have clockwise ordering in (u,v) or (u,v,w) space. If the order is `VertexOrderCcw`, the vertices will have counter-clockwise ordering in that space.

If the tessellation domain has an upper-left origin, the vertices of a triangle have counter-clockwise ordering if

  a = u0 v1 - u1 v0 + u1 v2 - u2 v1 + u2 v0 - u0 v2

is negative, and clockwise ordering if a is positive. ui and vi are the u and v coordinates in normalized parameter space of the ith vertex of the triangle. If the tessellation domain has a lower-left origin, the vertices of a triangle have counter-clockwise ordering if a is positive, and clockwise ordering if a is negative.

| Note The value a is proportional (with a positive factor) to the signed area of the triangle. In `Triangles` mode, even though the vertex coordinates have a w value, it does not participate directly in the computation of a, being an affine combination of u and v.

### 22.6. Triangle Tessellation

If the tessellation primitive mode is `Triangles`, an equilateral triangle is subdivided into a collection of triangles covering the area of the original triangle. First, the original triangle is subdivided into a collection of concentric equilateral triangles. The edges of each of these triangles are subdivided, and the area between each triangle pair is filled by triangles produced by joining the vertices on the subdivided edges. The number of concentric triangles and the number of subdivisions along each triangle except the outermost is derived from the first inner tessellation level. The edges of the outermost triangle are subdivided independently, using the first, second, and third outer tessellation levels to control the number of subdivisions of the u = 0 (left), v = 0 (bottom), and w = 0 (right) edges, respectively. The second inner tessellation level and the fourth outer tessellation level have no effect in this mode.

If the first inner tessellation level and all three outer tessellation levels are exactly one after clamping and rounding, only a single triangle with (u,v,w) coordinates of (0,0,1), (1,0,0), and (0,1,0) is generated. If the inner tessellation level is one and any of the outer tessellation levels is greater than one, the inner tessellation level is treated as though it were originally specified as 1 + ε and will result in a two- or three-segment subdivision depending on the tessellation spacing. When used with fractional odd spacing, the three-segment subdivision may produce inner vertices positioned on the edge of the triangle.

If any tessellation level is greater than one, tessellation begins by producing a set of concentric inner triangles and subdividing their edges. First, the three outer edges are temporarily subdivided using the clamped and rounded first inner tessellation level and the specified tessellation spacing, generating n segments. For the outermost inner triangle, the inner triangle is degenerate — a single point at the center of the triangle — if n is two. Otherwise, for each corner of the outer triangle, an inner triangle corner is produced at the intersection of two lines extended perpendicular to the corner’s two adjacent edges running through the vertex of the subdivided outer edge nearest that corner. If n is three, the edges of the inner triangle are not subdivided and is the final triangle in the set of concentric triangles. Otherwise, each edge of the inner triangle is divided into n - 2 segments, with the n - 1 vertices of this subdivision produced by intersecting the inner edge with lines perpendicular to the edge running through the n - 1 innermost vertices of the subdivision of the outer edge. Once the outermost inner triangle is subdivided, the previous subdivision process repeats itself, using the generated triangle as an outer triangle. This subdivision process is illustrated in Inner Triangle Tessellation.

Figure 14. Inner Triangle Tessellation
Caption

In the Inner Triangle Tessellation diagram, inner tessellation levels of (a) five and (b) four are shown (not to scale). Solid black circles depict vertices along the edges of the concentric triangles. The edges of inner triangles are subdivided by intersecting the edge with segments perpendicular to the edge passing through each inner vertex of the subdivided outer edge. Dotted lines depict edges connecting corresponding vertices on the inner and outer triangle edges.

Once all the concentric triangles are produced and their edges are subdivided, the area between each pair of adjacent inner triangles is filled completely with a set of non-overlapping triangles. In this subdivision, two of the three vertices of each triangle are taken from adjacent vertices on a subdivided edge of one triangle; the third is one of the vertices on the corresponding edge of the other triangle. If the innermost triangle is degenerate (i.e., a point), the triangle containing it is subdivided into six triangles by connecting each of the six vertices on that triangle with the center point. If the innermost triangle is not degenerate, that triangle is added to the set of generated triangles as-is.

After the area corresponding to any inner triangles is filled, the tessellator generates triangles to cover the area between the outermost triangle and the outermost inner triangle. To do this, the temporary subdivision of the outer triangle edge above is discarded. Instead, the u = 0, v = 0, and w = 0 edges are subdivided according to the first, second, and third outer tessellation levels, respectively, and the tessellation spacing. The original subdivision of the first inner triangle is retained. The area between the outer and first inner triangles is completely filled by non-overlapping triangles as described above. If the first (and only) inner triangle is degenerate, a set of triangles is produced by connecting each vertex on the outer triangle edges with the center point.

After all triangles are generated, each vertex in the subdivided triangle is assigned a barycentric (u,v,w) coordinate based on its location relative to the three vertices of the outer triangle.

The algorithm used to subdivide the triangular domain in (u,v,w) space into individual triangles is implementation-dependent. However, the set of triangles produced will completely cover the domain, and no portion of the domain will be covered by multiple triangles.

Output triangles are generated with a topology similar to triangle lists, except that the order in which each triangle is generated, and the order in which the vertices are generated for each triangle, are implementation-dependent. However, the order of vertices in each triangle is consistent across the domain as described in Tessellator Vertex Winding Order.

### 22.7. Quad Tessellation

If the tessellation primitive mode is `Quads`, a rectangle is subdivided into a collection of triangles covering the area of the original rectangle. First, the original rectangle is subdivided into a regular mesh of rectangles, where the number of rectangles along the u = 0 and u = 1 (vertical) and v = 0 and v = 1 (horizontal) edges are derived from the first and second inner tessellation levels, respectively. All rectangles, except those adjacent to one of the outer rectangle edges, are decomposed into triangle pairs. The outermost rectangle edges are subdivided independently, using the first, second, third, and fourth outer tessellation levels to control the number of subdivisions of the u = 0 (left), v = 0 (bottom), u = 1 (right), and v = 1 (top) edges, respectively. The area between the inner rectangles of the mesh and the outer rectangle edges are filled by triangles produced by joining the vertices on the subdivided outer edges to the vertices on the edge of the inner rectangle mesh.

If both clamped inner tessellation levels and all four clamped outer tessellation levels are exactly one, only a single triangle pair covering the outer rectangle is generated. Otherwise, if either clamped inner tessellation level is one, that tessellation level is treated as though it were originally specified as 1 + ε and will result in a two- or three-segment subdivision depending on the tessellation spacing. When used with fractional odd spacing, the three-segment subdivision may produce inner vertices positioned on the edge of the rectangle.

If any tessellation level is greater than one, tessellation begins by subdividing the u = 0 and u = 1 edges of the outer rectangle into m segments using the clamped and rounded first inner tessellation level and the tessellation spacing. The v = 0 and v = 1 edges are subdivided into n segments using the second inner tessellation level. Each vertex on the u = 0 and v = 0 edges are joined with the corresponding vertex on the u = 1 and v = 1 edges to produce a set of vertical and horizontal lines that divide the rectangle into a grid of smaller rectangles. The primitive generator emits a pair of non-overlapping triangles covering each such rectangle not adjacent to an edge of the outer rectangle. The boundary of the region covered by these triangles forms an inner rectangle, the edges of which are subdivided by the grid vertices that lie on the edge. If either m or n is two, the inner rectangle is degenerate, and one or both of the rectangle’s edges consist of a single point. This subdivision is illustrated in Figure Inner Quad Tessellation.

Figure 15. Inner Quad Tessellation
Caption

In the Inner Quad Tessellation diagram, inner quad tessellation levels of (a) (4,2) and (b) (7,4) are shown. The regions highlighted in red in figure (b) depict the 10 inner rectangles, each of which will be subdivided into two triangles. Solid black circles depict vertices on the boundary of the outer and inner rectangles, where the inner rectangle on the top figure is degenerate (a single line segment). Dotted lines depict the horizontal and vertical edges connecting corresponding vertices on the inner and outer rectangle edges.

After the area corresponding to the inner rectangle is filled, the tessellator must produce triangles to cover the area between the inner and outer rectangles. To do this, the subdivision of the outer rectangle edge above is discarded. Instead, the u = 0, v = 0, u = 1, and v = 1 edges are subdivided according to the first, second, third, and fourth outer tessellation levels, respectively, and the tessellation spacing. The original subdivision of the inner rectangle is retained. The area between the outer and inner rectangles is completely filled by non-overlapping triangles. Two of the three vertices of each triangle are adjacent vertices on a subdivided edge of one rectangle; the third is one of the vertices on the corresponding edge of the other rectangle. If either edge of the innermost rectangle is degenerate, the area near the corresponding outer edges is filled by connecting each vertex on the outer edge with the single vertex making up the inner edge.

The algorithm used to subdivide the rectangular domain in (u,v) space into individual triangles is implementation-dependent. However, the set of triangles produced will completely cover the domain, and no portion of the domain will be covered by multiple triangles.

Output triangles are generated with a topology similar to triangle lists, except that the order in which each triangle is generated, and the order in which the vertices are generated for each triangle, are implementation-dependent. However, the order of vertices in each triangle is consistent across the domain as described in Tessellator Vertex Winding Order.

### 22.8. Isoline Tessellation

If the tessellation primitive mode is `IsoLines`, a set of independent horizontal line segments is drawn. The segments are arranged into connected strips called isolines, where the vertices of each isoline have a constant v coordinate and u coordinates covering the full range [0,1]. The number of isolines generated is derived from the first outer tessellation level; the number of segments in each isoline is derived from the second outer tessellation level. Both inner tessellation levels and the third and fourth outer tessellation levels have no effect in this mode.

As with quad tessellation above, isoline tessellation begins with a rectangle. The u = 0 and u = 1 edges of the rectangle are subdivided according to the first outer tessellation level. For the purposes of this subdivision, the tessellation spacing mode is ignored and treated as equal_spacing. An isoline is drawn connecting each vertex on the u = 0 rectangle edge to the corresponding vertex on the u = 1 rectangle edge, except that no line is drawn between (0,1) and (1,1). If the number of isolines on the subdivided u = 0 and u = 1 edges is n, this process will result in n equally spaced lines with constant v coordinates of 0, \(\frac{1}{n}, \frac{2}{n}, \ldots, \frac{n-1}{n}\).

Each of the n isolines is then subdivided according to the second outer tessellation level and the tessellation spacing, resulting in m line segments. Each segment of each line is emitted by the tessellator. These line segments are generated with a topology similar to line lists, except that the order in which each line is generated, and the order in which the vertices are generated for each line segment, are implementation-dependent.

### 22.9. Tessellation Point Mode

For all primitive modes, the tessellator is capable of generating points instead of lines or triangles. If the tessellation control or tessellation evaluation shader specifies the `OpExecutionMode` `PointMode`, the primitive generator will generate one point for each distinct vertex produced by tessellation, rather than emitting triangles or lines. Otherwise, the tessellator will produce a collection of line segments or triangles according to the primitive mode. These points are generated with a topology similar to point lists, except the order in which the points are generated for each input primitive is undefined.

### 22.10. Tessellation Pipeline State

The `pTessellationState` member of VkGraphicsPipelineCreateInfo is a pointer to a `VkPipelineTessellationStateCreateInfo` structure.

The `VkPipelineTessellationStateCreateInfo` structure is defined as:

    typedef struct VkPipelineTessellationStateCreateInfo {
        VkStructureType                           sType;
        const void*                               pNext;
        VkPipelineTessellationStateCreateFlags    flags;
        uint32_t                                  patchControlPoints;
    } VkPipelineTessellationStateCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `patchControlPoints` number of control points per patch.

Valid Usage

- `patchControlPoints` must be greater than zero and less than or equal to `VkPhysicalDeviceLimits`::`maxTessellationPatchSize`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_TESSELLATION_STATE_CREATE_INFO`

- `pNext` must be `NULL` or a pointer to a valid instance of VkPipelineTessellationDomainOriginStateCreateInfo

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be `0`

    typedef VkFlags VkPipelineTessellationStateCreateFlags;

`VkPipelineTessellationStateCreateFlags` is a bitmask type for setting a mask, but is currently reserved for future use.

The `VkPipelineTessellationDomainOriginStateCreateInfo` structure is defined as:

    typedef struct VkPipelineTessellationDomainOriginStateCreateInfo {
        VkStructureType               sType;
        const void*                   pNext;
        VkTessellationDomainOrigin    domainOrigin;
    } VkPipelineTessellationDomainOriginStateCreateInfo;

or the equivalent

    typedef VkPipelineTessellationDomainOriginStateCreateInfo VkPipelineTessellationDomainOriginStateCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `domainOrigin` is a VkTessellationDomainOrigin value controlling the origin of the tessellation domain space.

If the `VkPipelineTessellationDomainOriginStateCreateInfo` structure is included in the `pNext` chain of VkPipelineTessellationStateCreateInfo, it controls the origin of the tessellation domain. If this structure is not present, it is as if `domainOrigin` were `VK_TESSELLATION_DOMAIN_ORIGIN_UPPER_LEFT`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_TESSELLATION_DOMAIN_ORIGIN_STATE_CREATE_INFO`

- `domainOrigin` must be a valid VkTessellationDomainOrigin value

The possible tessellation domain origins are specified by the VkTessellationDomainOrigin enumeration:

    typedef enum VkTessellationDomainOrigin {
        VK_TESSELLATION_DOMAIN_ORIGIN_UPPER_LEFT = 0,
        VK_TESSELLATION_DOMAIN_ORIGIN_LOWER_LEFT = 1,
        VK_TESSELLATION_DOMAIN_ORIGIN_UPPER_LEFT_KHR = VK_TESSELLATION_DOMAIN_ORIGIN_UPPER_LEFT,
        VK_TESSELLATION_DOMAIN_ORIGIN_LOWER_LEFT_KHR = VK_TESSELLATION_DOMAIN_ORIGIN_LOWER_LEFT,
        VK_TESSELLATION_DOMAIN_ORIGIN_MAX_ENUM = 0x7FFFFFFF
    } VkTessellationDomainOrigin;

or the equivalent

    typedef VkTessellationDomainOrigin VkTessellationDomainOriginKHR;

- `VK_TESSELLATION_DOMAIN_ORIGIN_UPPER_LEFT` specifies that the origin of the domain space is in the upper left corner, as shown in figure Domain parameterization for tessellation primitive modes (upper-left origin).

- `VK_TESSELLATION_DOMAIN_ORIGIN_LOWER_LEFT` specifies that the origin of the domain space is in the lower left corner, as shown in figure Domain parameterization for tessellation primitive modes (lower-left origin).

This enum affects how the `VertexOrderCw` and `VertexOrderCcw` tessellation execution modes are interpreted, since the winding is defined relative to the orientation of the domain.

## 23. Geometry Shading

The geometry shader operates on a group of vertices and their associated data assembled from a single input primitive, and emits zero or more output primitives and the group of vertices and their associated data required for each output primitive. Geometry shading is enabled when a geometry shader is included in the pipeline.

### 23.1. Geometry Shader Input Primitives

Each geometry shader invocation has access to all vertices in the primitive (and their associated data), which are presented to the shader as an array of inputs.

The input primitive type expected by the geometry shader is specified with an `OpExecutionMode` instruction in the geometry shader, and must match the incoming primitive type specified by either the pipeline’s primitive topology if tessellation is inactive, or the tessellation mode if tessellation is active, as follows:

- An input primitive type of `InputPoints` must only be used with a pipeline topology of `VK_PRIMITIVE_TOPOLOGY_POINT_LIST`, or with a tessellation shader that specifies `PointMode`. The input arrays always contain one element, as described by the point list topology or tessellation in point mode.

- An input primitive type of `InputLines` must only be used with a pipeline topology of `VK_PRIMITIVE_TOPOLOGY_LINE_LIST` or `VK_PRIMITIVE_TOPOLOGY_LINE_STRIP`, or with a tessellation shader specifying `IsoLines` that does not specify `PointMode`. The input arrays always contain two elements, as described by the line list topology or line strip topology, or by isoline tessellation.

- An input primitive type of `InputLinesAdjacency` must only be used when tessellation is inactive, with a pipeline topology of `VK_PRIMITIVE_TOPOLOGY_LINE_LIST_WITH_ADJACENCY` or `VK_PRIMITIVE_TOPOLOGY_LINE_STRIP_WITH_ADJACENCY`. The input arrays always contain four elements, as described by the line list with adjacency topology or line strip with adjacency topology.

- An input primitive type of `Triangles` must only be used with a pipeline topology of `VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST`, `VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP`, or `VK_PRIMITIVE_TOPOLOGY_TRIANGLE_FAN`; or with a tessellation shader specifying `Quads` or `Triangles` that does not specify `PointMode`. The input arrays always contain three elements, as described by the triangle list topology, triangle strip topology, or triangle fan topology, or by triangle or quad tessellation. Vertices may be in a different absolute order to that specified by the topology, but must adhere to the specified winding order.

- An input primitive type of `InputTrianglesAdjacency` must only be used when tessellation is inactive, with a pipeline topology of `VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST_WITH_ADJACENCY` or `VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP_WITH_ADJACENCY`. The input arrays always contain six elements, as described by the triangle list with adjacency topology or triangle strip with adjacency topology. Vertices may be in a different absolute order to that specified by the topology, but must adhere to the specified winding order, and the vertices making up the main primitive must still occur at the first, third, and fifth index.

### 23.2. Geometry Shader Output Primitives

A geometry shader generates primitives in one of three output modes: points, line strips, or triangle strips. The primitive mode is specified in the shader using an `OpExecutionMode` instruction with the `OutputPoints`, `OutputLineStrip` or `OutputTriangleStrip` modes, respectively. Each geometry shader must include exactly one output primitive mode.

The vertices output by the geometry shader are assembled into points, lines, or triangles based on the output primitive type and the resulting primitives are then further processed as described in Rasterization. If the number of vertices emitted by the geometry shader is not sufficient to produce a single primitive, vertices corresponding to incomplete primitives are not processed by subsequent pipeline stages. The number of vertices output by the geometry shader is limited to a maximum count specified in the shader.

The maximum output vertex count is specified in the shader using an `OpExecutionMode` instruction with the mode set to `OutputVertices` and the maximum number of vertices that will be produced by the geometry shader specified as a literal. Each geometry shader must specify a maximum output vertex count.

### 23.3. Multiple Invocations of Geometry Shaders

Geometry shaders can be invoked more than one time for each input primitive. This is known as geometry shader instancing and is requested by including an `OpExecutionMode` instruction with `mode` specified as `Invocations` and the number of invocations specified as an integer literal.

In this mode, the geometry shader will execute at least n times for each input primitive, where n is the number of invocations specified in the `OpExecutionMode` instruction. The instance number is available to each invocation as a built-in input using `InvocationId`.

### 23.4. Geometry Shader Primitive Ordering

Limited guarantees are provided for the relative ordering of primitives produced by a geometry shader, as they pertain to primitive order.

- For instanced geometry shaders, the output primitives generated from each input primitive are passed to subsequent pipeline stages using the invocation number to order the primitives, from least to greatest.

- All output primitives generated from a given input primitive are passed to subsequent pipeline stages before any output primitives generated from subsequent input primitives.

### 23.5. Geometry Shader Passthrough

A geometry shader that uses the `PassthroughNV` decoration on a variable in its input interface is considered a passthrough geometry shader. Output primitives in a passthrough geometry shader must have the same topology as the input primitive and are not produced by emitting vertices. The vertices of the output primitive have two different types of attributes, per-vertex and per-primitive. Geometry shader input variables with `PassthroughNV` decoration are considered to produce per-vertex outputs, where values for each output vertex are copied from the corresponding input vertex. Any built-in or user-defined geometry shader outputs are considered per-primitive in a passthrough geometry shader, where a single output value is copied to all output vertices.

The remainder of this section details the usage of the `PassthroughNV` decoration and modifications to the interface matching rules when using passthrough geometry shaders.

#### 23.5.1. `PassthroughNV` Decoration

Decorating a geometry shader input variable with the `PassthroughNV` decoration indicates that values of this input are copied through to the corresponding vertex of the output primitive. Input variables and block members which do not have the `PassthroughNV` decoration are consumed by the geometry shader without being passed through to subsequent stages.

The `PassthroughNV` decoration must only be used within a geometry shader.

Any variable decorated with `PassthroughNV` must be declared using the `Input` storage class.

The `PassthroughNV` decoration must not be used with any of:

- an input primitive type other than `InputPoints`, `InputLines`, or `Triangles`, as specified by the mode for `OpExecutionMode`.

- an invocation count other than one, as specified by the `Invocations` mode for `OpExecutionMode`.

- an `OpEntryPoint` which statically uses the `OpEmitVertex` or `OpEndPrimitive` instructions.

- a variable decorated with the `InvocationId` built-in decoration.

- a variable decorated with the `PrimitiveId` built-in decoration that is declared using the `Input` storage class.

#### 23.5.2. Passthrough Interface Matching

When a passthrough geometry shader is in use, the Interface Matching rules involving the geometry shader input and output interfaces operate as described in this section.

For the purposes of matching passthrough geometry shader inputs with outputs of the previous pipeline stages, the `PassthroughNV` decoration is ignored.

For the purposes of matching the outputs of the geometry shader with subsequent pipeline stages, each input variable with the `PassthroughNV` decoration is considered to add an equivalent output variable with the same type, decoration (other than `PassthroughNV`), number, and declaration order on the output interface. The output variable declaration corresponding to an input variable decorated with `PassthroughNV` will be identical to the input declaration, except that the outermost array dimension of such variables is removed. The output block declaration corresponding to an input block decorated with `PassthroughNV` or having members decorated with `PassthroughNV` will be identical to the input declaration, except that the outermost array dimension of such declaration is removed.

If an input block is decorated with `PassthroughNV`, the equivalent output block contains all the members of the input block. Otherwise, the equivalent output block contains only those input block members decorated with `PassthroughNV`. All members of the corresponding output block are assigned `Location` and `Component` decorations identical to those assigned to the corresponding input block members.

Output variables and blocks generated from inputs decorated with `PassthroughNV` will only exist for the purposes of interface matching; these declarations are not available to geometry shader code or listed in the module interface.

For the purposes of component counting, passthrough geometry shaders count all statically used input variable components declared with the `PassthroughNV` decoration as output components as well, since their values will be copied to the output primitive produced by the geometry shader.

## 24. Mesh Shading

Task and mesh shaders operate in workgroups to produce a collection of primitives that will be processed by subsequent stages of the graphics pipeline.

Work on the mesh pipeline is initiated by the application drawing a set of mesh tasks organized in global workgroups. If the optional task shader is active, each workgroup triggers the execution of task shader invocations that will create a new set of mesh workgroups upon completion. Each of these created workgroups, or each of the original workgroups if no task shader is present, triggers the execution of mesh shader invocations.

Each mesh shader workgroup emits zero or more output primitives along with the group of vertices and their associated data required for each output primitive.

### 24.1. Task Shader Input

For every workgroup issued via the drawing commands a group of task shader invocations is executed. There are no inputs other than the builtin workgroup identifiers.

### 24.2. Task Shader Output

The task shader can emit zero or more mesh workgroups to be generated using the built-in variable `TaskCountNV`. This value must be less than or equal to `VkPhysicalDeviceMeshShaderPropertiesNV`::`maxTaskOutputCount`.

It can also output user-defined data that is passed as input to all mesh shader invocations that the task creates. These outputs are decorated as `PerTaskNV`.

### 24.3. Mesh Generation

If a task shader exists, the mesh assembler creates a variable amount of mesh workgroups depending on each task’s output. If there is no task shader, the drawing commands emit the mesh shader invocations directly.

### 24.4. Mesh Shader Input

The only inputs available to the mesh shader are variables identifying the specific workgroup and invocation and, if applicable, any outputs written as `PerTaskNV` by the task shader that spawned the mesh shader’s workgroup. The mesh shader can operate without a task shader as well.

### 24.5. Mesh Shader Output Primitives

A mesh shader generates primitives in one of three output modes: points, lines, or triangles. The primitive mode is specified in the shader using an `OpExecutionMode` instruction with the `OutputPoints`, `OutputLinesNV`, or `OutputTrianglesNV` modes, respectively. Each mesh shader must include exactly one output primitive mode.

The maximum output vertex count is specified as a literal in the shader using an `OpExecutionMode` instruction with the mode set to `OutputVertices` and must be less than or equal to `VkPhysicalDeviceMeshShaderPropertiesNV`::`maxMeshOutputVertices`.

The maximum output primitive count is specified as a literal in the shader using an `OpExecutionMode` instruction with the mode set to `OutputPrimitivesNV` and must be less than or equal to `VkPhysicalDeviceMeshShaderPropertiesNV`::`maxMeshOutputPrimitives`.

The number of primitives output by the mesh shader is provided via writing to the built-in variable `PrimitiveCountNV` and must be less than or equal to the maximum output primitive count specified in the shader. A variable decorated with `PrimitiveIndicesNV` is an output array of local index values into the vertex output arrays from which primitives are assembled according to the output primitive type. These resulting primitives are then further processed as described in Rasterization.

### 24.6. Mesh Shader Per-View Outputs

The mesh shader outputs decorated with the `PositionPerViewNV`, `ClipDistancePerViewNV`, `CullDistancePerViewNV`, `LayerPerViewNV`, and `ViewportMaskPerViewNV` built-in decorations are the per-view versions of the single-view variables with equivalent names (that is `Position`, `ClipDistance`, `CullDistance`, `Layer`, and `ViewportMaskNV`, respectively). If a shader statically assigns a value to any element of a per-view array it must not statically assign a value to the equivalent single-view variable.

Each of these outputs is considered arrayed, with separate values for each view. The view number is used to index the first dimension of these arrays.

The second dimension of the `ClipDistancePerViewNV`, and `CullDistancePerViewNV` arrays have the same requirements as the `ClipDistance`, and `CullDistance` arrays.

If a mesh shader output is per-view, the corresponding fragment shader input is taken from the element of the per-view output array that corresponds to the view that is currently being processed by the fragment shader.

### 24.7. Mesh Shader Primitive Ordering

Following guarantees are provided for the relative ordering of primitives produced by a mesh shader, as they pertain to primitive order.

- When a task shader is used, mesh workgroups spawned from lower tasks will be ordered prior those workgroups from subsequent tasks.

- All output primitives generated from a given mesh workgroup are passed to subsequent pipeline stages before any output primitives generated from subsequent input workgroups.

- All output primitives within a mesh workgroup, will be generated in the ordering provided by the builtin primitive indexbuffer (from low address to high address).

## 25. Fixed-Function Vertex Post-Processing

After programmable vertex processing, the following fixed-function operations are applied to vertices of the resulting primitives:

- Transform feedback (see Transform Feedback)

- Viewport swizzle (see Viewport Swizzle)

- Flat shading (see Flat Shading).

- Primitive clipping, including client-defined half-spaces (see Primitive Clipping).

- Shader output attribute clipping (see Clipping Shader Outputs).

- Clip space W scaling (see Controlling Viewport W Scaling).

- Perspective division on clip coordinates (see Coordinate Transformations).

- Viewport mapping, including depth range scaling (see Controlling the Viewport).

- Front face determination for polygon primitives (see Basic Polygon Rasterization).

| editing-note TODO:Odd that this one link to a different chapter is in this list.

Next, rasterization is performed on primitives as described in chapter Rasterization.

### 25.1. Transform Feedback

Before any other fixed-function vertex post-processing, vertex outputs from the last shader in the vertex processing stage can be written out to one or more transform feedback buffers bound to the command buffer. To capture vertex outputs the last vertex processing stage shader must be declared with the `Xfb` execution mode. Outputs decorated with `XfbBuffer` will be written out to the corresponding transform feedback buffers bound to the command buffer when transform feedback is active. Transform feedback buffers are bound to the command buffer by using vkCmdBindTransformFeedbackBuffersEXT. Transform feedback is made active by calling vkCmdBeginTransformFeedbackEXT and made inactive by calling vkCmdEndTransformFeedbackEXT. After vertex data is written it is possible to use vkCmdDrawIndirectByteCountEXT to start a new draw where the `vertexCount` is derived from the number of bytes written by a previous transform feedback.

When an individual point, line, or triangle primitive reaches the transform feedback stage while transform feedback is active, the values of the specified output variables are assembled into primitives and appended to the bound transform feedback buffers. After activating transform feedback, the values of the first assembled primitive are written at the starting offsets of the bound transform feedback buffers, and subsequent primitives are appended to the buffer. If the optional `pCounterBuffers` and `pCounterBufferOffsets` parameters are specified, the starting points within the transform feedback buffers are adjusted so data is appended to the previously written values indicated by the value stored by the implementation in the counter buffer.

For multi-vertex primitives, all values for a given vertex are written before writing values for any other vertex. Implementations may write out any vertex within the primitive first, but all subsequent vertices for that primitive must be written out in a consistent winding order defined as follows:

- If neither geometry or tessellation shading is active, vertices within a primitive are appended according to the winding order described by the primitive topology defined by the VkPipelineInputAssemblyStateCreateInfo:`topology` used to execute the drawing command.

- If geometry shading is active, vertices within a primitive are appended according to the winding order described by the primitive topology defined by the `OutputPoints`, `OutputLineStrips`, or `OutputTriangleStrips` execution mode.

- If tessellation shading is active but geometry shading is not, vertices within a primitive are appended according to the winding order defined by triangle tessellation, quad tessellation, and isoline tessellation.

When capturing vertices, the stride associated with each transform feedback buffer, as indicated by the `XfbStride` decoration, indicates the number of bytes of storage reserved for each vertex in the transform feedback buffer. For every vertex captured, each output attribute with a `Offset` decoration will be written to the storage reserved for the vertex at the associated transform feedback buffer. When writing output variables that are arrays or structures, individual array elements or structure members are written tightly packed in order. For vector types, individual components are written in order. For matrix types, outputs are written as an array of column vectors.

If any component of an output with an assigned transform feedback offset was not written to by its shader, the value recorded for that component is undefined. All components of an output variable must be written at an offset aligned to the size of the component. The size of each component of an output variable must be at least 32-bits. When capturing a vertex, any portion of the reserved storage not associated with an output variable with an assigned transform feedback offset will be unmodified.

When transform feedback is inactive, no vertices are recorded. If there is a valid counter buffer handle and counter buffer offset in the `pCounterBuffers` and `pCounterBufferOffsets` arrays, writes to the corresponding transform feedback buffer will start at the byte offset represented by the value stored in the counter buffer location.

Individual lines or triangles of a strip or fan primitive will be extracted and recorded separately. Incomplete primitives are not recorded.

When using a geometry shader that emits vertices to multiple vertex streams, a primitive will be assembled and output for each stream when there are enough vertices emitted for the output primitive type. All outputs assigned to a given transform feedback buffer are required to come from a single vertex stream.

The sizes of the transform feedback buffers are defined by the vkCmdBindTransformFeedbackBuffersEXT `pSizes` parameter for each of the bound buffers, or the size of the bound buffer, whichever is the lesser. If there is less space remaining in any of the transform feedback buffers than the size of the all the vertex data for that primitive based on the `XfbStride` for that `XfbBuffer` then no vertex data of that primitive is recorded in any transform feedback buffer, and the value for the number of primitives written in the corresponding `VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT` query for all transform feedback buffers is no longer incremented.

Any outputs made to a `XfbBuffer` that is not bound to a transform feedback buffer is ignored.

To bind transform feedback buffers to a command buffer for use in subsequent draw commands, call:

    void vkCmdBindTransformFeedbackBuffersEXT(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    firstBinding,
        uint32_t                                    bindingCount,
        const VkBuffer*                             pBuffers,
        const VkDeviceSize*                         pOffsets,
        const VkDeviceSize*                         pSizes);

- `commandBuffer` is the command buffer into which the command is recorded.

- `firstBinding` is the index of the first transform feedback binding whose state is updated by the command.

- `bindingCount` is the number of transform feedback bindings whose state is updated by the command.

- `pBuffers` is a pointer to an array of buffer handles.

- `pOffsets` is a pointer to an array of buffer offsets.

- `pSizes` is an optional array of buffer sizes, specifying the maximum number of bytes to capture to the corresponding transform feedback buffer. If `pSizes` is `NULL`, or the value of the `pSizes` array element is `VK_WHOLE_SIZE`, then the maximum bytes captured will be the size of the corresponding buffer minus the buffer offset.

The values taken from elements i of `pBuffers`, `pOffsets` and `pSizes` replace the current state for the transform feedback binding `firstBinding` + i, for i in [0, `bindingCount`). The transform feedback binding is updated to start at the offset indicated by `pOffsets`[i] from the start of the buffer `pBuffers`[i].

Valid Usage

- `VkPhysicalDeviceTransformFeedbackFeaturesEXT`::`transformFeedback` must be enabled

- `firstBinding` must be less than `VkPhysicalDeviceTransformFeedbackPropertiesEXT`::`maxTransformFeedbackBuffers`

- The sum of `firstBinding` and `bindingCount` must be less than or equal to `VkPhysicalDeviceTransformFeedbackPropertiesEXT`::`maxTransformFeedbackBuffers`

- All elements of `pOffsets` must be less than the size of the corresponding element in `pBuffers`

- All elements of `pOffsets` must be a multiple of 4

- All elements of `pBuffers` must have been created with the `VK_BUFFER_USAGE_TRANSFORM_FEEDBACK_BUFFER_BIT_EXT` flag

- If the optional `pSize` array is specified, each element of `pSizes` must either be `VK_WHOLE_SIZE`, or be less than or equal to `VkPhysicalDeviceTransformFeedbackPropertiesEXT`::`maxTransformFeedbackBufferSize`

- All elements of `pSizes` must be less than or equal to the size of the corresponding buffer in `pBuffers`

- All elements of `pOffsets` plus `pSizes`, where the `pSizes`, element is not `VK_WHOLE_SIZE`, must be less than or equal to the size of the corresponding element in `pBuffers`

- Each element of `pBuffers` that is non-sparse must be bound completely and contiguously to a single `VkDeviceMemory` object

- Transform feedback must not be active when the `vkCmdBindTransformFeedbackBuffersEXT` command is recorded

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pBuffers` must be a valid pointer to an array of `bindingCount` valid VkBuffer handles

- `pOffsets` must be a valid pointer to an array of `bindingCount` `VkDeviceSize` values

- If `pSizes` is not `NULL`, `pSizes` must be a valid pointer to an array of `bindingCount` `VkDeviceSize` values

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- If `pSizes` is not `NULL`, `bindingCount` must be greater than `0`

- Both of `commandBuffer`, and the elements of `pBuffers` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics |

Transform feedback for specific transform feedback buffers is made active by calling:

    void vkCmdBeginTransformFeedbackEXT(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    firstCounterBuffer,
        uint32_t                                    counterBufferCount,
        const VkBuffer*                             pCounterBuffers,
        const VkDeviceSize*                         pCounterBufferOffsets);

- `commandBuffer` is the command buffer into which the command is recorded.

- `firstCounterBuffer` is the index of the first transform feedback buffer corresponding to `pCounterBuffers`[0] and `pCounterBufferOffsets`[0].

- `counterBufferCount` is the size of the `pCounterBuffers` and `pCounterBufferOffsets` arrays.

- `pCounterBuffers` is an optional array of buffer handles to the counter buffers which contain a 4 byte integer value representing the byte offset from the start of the corresponding transform feedback buffer from where to start capturing vertex data. If the byte offset stored to the counter buffer location was done using vkCmdEndTransformFeedbackEXT it can be used to resume transform feedback from the previous location. If `pCounterBuffers` is `NULL`, then transform feedback will start capturing vertex data to byte offset zero in all bound transform feedback buffers. For each element of `pCounterBuffers` that is VK_NULL_HANDLE, transform feedback will start capturing vertex data to byte zero in the corresponding bound transform feedback buffer.

- `pCounterBufferOffsets` is an optional array of offsets within each of the `pCounterBuffers` where the counter values were previously written. The location in each counter buffer at these offsets must be large enough to contain 4 bytes of data. This data is the number of bytes captured by the previous transform feedback to this buffer. If `pCounterBufferOffsets` is `NULL`, then it is assumed the offsets are zero.

The active transform feedback buffers will capture primitives emitted from the corresponding `XfbBuffer` in the bound graphics pipeline. Any `XfbBuffer` emitted that does not output to an active transform feedback buffer will not be captured.

Valid Usage

- `VkPhysicalDeviceTransformFeedbackFeaturesEXT`::`transformFeedback` must be enabled

- Transform feedback must not be active

- `firstCounterBuffer` must be less than `VkPhysicalDeviceTransformFeedbackPropertiesEXT`::`maxTransformFeedbackBuffers`

- The sum of `firstCounterBuffer` and `counterBufferCount` must be less than or equal to `VkPhysicalDeviceTransformFeedbackPropertiesEXT`::`maxTransformFeedbackBuffers`

- If `counterBufferCount` is not `0`, and `pCounterBuffers` is not `NULL`, `pCounterBuffers` must be a valid pointer to an array of `counterBufferCount` `VkBuffer` handles that are either valid or VK_NULL_HANDLE

- For each buffer handle in the array, if it is not VK_NULL_HANDLE it must reference a buffer large enough to hold 4 bytes at the corresponding offset from the `pCounterBufferOffsets` array

- If `pCounterBuffer` is `NULL`, then `pCounterBufferOffsets` must also be `NULL`

- For each buffer handle in the `pCounterBuffers` array that is not VK_NULL_HANDLE it must have been created with a `usage` value containing `VK_BUFFER_USAGE_TRANSFORM_FEEDBACK_COUNTER_BUFFER_BIT_EXT`

- Transform feedback must not be made active in a render pass instance with multiview enabled

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- If `counterBufferCount` is not `0`, and `pCounterBufferOffsets` is not `NULL`, `pCounterBufferOffsets` must be a valid pointer to an array of `counterBufferCount` `VkDeviceSize` values

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- This command must only be called inside of a render pass instance

- Both of `commandBuffer`, and the elements of `pCounterBuffers` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Inside | Graphics |

Transform feedback for specific transform feedback buffers is made inactive by calling:

    void vkCmdEndTransformFeedbackEXT(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    firstCounterBuffer,
        uint32_t                                    counterBufferCount,
        const VkBuffer*                             pCounterBuffers,
        const VkDeviceSize*                         pCounterBufferOffsets);

- `commandBuffer` is the command buffer into which the command is recorded.

- `firstCounterBuffer` is the index of the first transform feedback buffer corresponding to `pCounterBuffers`[0] and `pCounterBufferOffsets`[0].

- `counterBufferCount` is the size of the `pCounterBuffers` and `pCounterBufferOffsets` arrays.

- `pCounterBuffers` is an optional array of buffer handles to the counter buffers used to record the current byte positions of each transform feedback buffer where the next vertex output data would be captured. This can be used by a subsequent vkCmdBeginTransformFeedbackEXT call to resume transform feedback capture from this position. It can also be used by vkCmdDrawIndirectByteCountEXT to determine the vertex count of the draw call.

- `pCounterBufferOffsets` is an optional array of offsets within each of the `pCounterBuffers` where the counter values can be written. The location in each counter buffer at these offsets must be large enough to contain 4 bytes of data. The data stored at this location is the byte offset from the start of the transform feedback buffer binding where the next vertex data would be written. If `pCounterBufferOffsets` is `NULL`, then it is assumed the offsets are zero.

Valid Usage

- `VkPhysicalDeviceTransformFeedbackFeaturesEXT`::`transformFeedback` must be enabled

- Transform feedback must be active

- `firstCounterBuffer` must be less than `VkPhysicalDeviceTransformFeedbackPropertiesEXT`::`maxTransformFeedbackBuffers`

- The sum of `firstCounterBuffer` and `counterBufferCount` must be less than or equal to `VkPhysicalDeviceTransformFeedbackPropertiesEXT`::`maxTransformFeedbackBuffers`

- If `counterBufferCount` is not `0`, and `pCounterBuffers` is not `NULL`, `pCounterBuffers` must be a valid pointer to an array of `counterBufferCount` `VkBuffer` handles that are either valid or VK_NULL_HANDLE

- For each buffer handle in the array, if it is not VK_NULL_HANDLE it must reference a buffer large enough to hold 4 bytes at the corresponding offset from the `pCounterBufferOffsets` array

- If `pCounterBuffer` is `NULL`, then `pCounterBufferOffsets` must also be `NULL`

- For each buffer handle in the `pCounterBuffers` array that is not VK_NULL_HANDLE it must have been created with a `usage` value containing `VK_BUFFER_USAGE_TRANSFORM_FEEDBACK_COUNTER_BUFFER_BIT_EXT`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- If `counterBufferCount` is not `0`, and `pCounterBufferOffsets` is not `NULL`, `pCounterBufferOffsets` must be a valid pointer to an array of `counterBufferCount` `VkDeviceSize` values

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- This command must only be called inside of a render pass instance

- Both of `commandBuffer`, and the elements of `pCounterBuffers` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Inside | Graphics |

### 25.2. Viewport Swizzle

Each primitive sent to a given viewport has a swizzle and optional negation applied to its clip coordinates. The swizzle that is applied depends on the viewport index, and is controlled by the `VkPipelineViewportSwizzleStateCreateInfoNV` pipeline state:

    typedef struct VkPipelineViewportSwizzleStateCreateInfoNV {
        VkStructureType                                sType;
        const void*                                    pNext;
        VkPipelineViewportSwizzleStateCreateFlagsNV    flags;
        uint32_t                                       viewportCount;
        const VkViewportSwizzleNV*                     pViewportSwizzles;
    } VkPipelineViewportSwizzleStateCreateInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `viewportCount` is the number of viewport swizzles used by the pipeline.

- `pViewportSwizzles` is a pointer to an array of VkViewportSwizzleNV structures, defining the viewport swizzles.

Valid Usage

- `viewportCount` must match the `viewportCount` set in `VkPipelineViewportStateCreateInfo`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_SWIZZLE_STATE_CREATE_INFO_NV`

- `flags` must be `0`

- `pViewportSwizzles` must be a valid pointer to an array of `viewportCount` valid VkViewportSwizzleNV structures

- `viewportCount` must be greater than `0`

    typedef VkFlags VkPipelineViewportSwizzleStateCreateFlagsNV;

`VkPipelineViewportSwizzleStateCreateFlagsNV` is a bitmask type for setting a mask, but is currently reserved for future use.

The `VkPipelineViewportSwizzleStateCreateInfoNV` state is set by adding this structure to the `pNext` chain of a `VkPipelineViewportStateCreateInfo` structure and setting the graphics pipeline state with vkCreateGraphicsPipelines.

Each viewport specified from 0 to `viewportCount` - 1 has its x,y,z,w swizzle state set to the corresponding `x`, `y`, `z` and `w` in the VkViewportSwizzleNV structure. Each component is of type VkViewportCoordinateSwizzleNV, which determines the type of swizzle for that component. The value of `x` computes the new x component of the position as:

    if (x == VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_X_NV) x' = x;
    if (x == VK_VIEWPORT_COORDINATE_SWIZZLE_NEGATIVE_X_NV) x' = -x;
    if (x == VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_Y_NV) x' = y;
    if (x == VK_VIEWPORT_COORDINATE_SWIZZLE_NEGATIVE_Y_NV) x' = -y;
    if (x == VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_Z_NV) x' = z;
    if (x == VK_VIEWPORT_COORDINATE_SWIZZLE_NEGATIVE_Z_NV) x' = -z;
    if (x == VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_W_NV) x' = w;
    if (x == VK_VIEWPORT_COORDINATE_SWIZZLE_NEGATIVE_W_NV) x' = -w;

Similar selections are performed for the `y`, `z`, and `w` coordinates. This swizzling is applied before clipping and perspective divide. If the swizzle for an active viewport index is not specified, the swizzle for `x` is `VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_X_NV`, `y` is `VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_Y_NV`, `z` is `VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_Z_NV` and `w` is `VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_W_NV`.

Viewport swizzle parameters are specified by setting the `pNext` pointer of `VkGraphicsPipelineCreateInfo` to point to a `VkPipelineViewportSwizzleStateCreateInfoNV` structure. VkPipelineViewportSwizzleStateCreateInfoNV uses `VkViewportSwizzleNV` to set the viewport swizzle parameters.

The `VkViewportSwizzleNV` structure is defined as:

    typedef struct VkViewportSwizzleNV {
        VkViewportCoordinateSwizzleNV    x;
        VkViewportCoordinateSwizzleNV    y;
        VkViewportCoordinateSwizzleNV    z;
        VkViewportCoordinateSwizzleNV    w;
    } VkViewportSwizzleNV;

- `x` is a VkViewportCoordinateSwizzleNV value specifying the swizzle operation to apply to the x component of the primitive

- `y` is a VkViewportCoordinateSwizzleNV value specifying the swizzle operation to apply to the y component of the primitive

- `z` is a VkViewportCoordinateSwizzleNV value specifying the swizzle operation to apply to the z component of the primitive

- `w` is a VkViewportCoordinateSwizzleNV value specifying the swizzle operation to apply to the w component of the primitive

Valid Usage (Implicit)

- `x` must be a valid VkViewportCoordinateSwizzleNV value

- `y` must be a valid VkViewportCoordinateSwizzleNV value

- `z` must be a valid VkViewportCoordinateSwizzleNV value

- `w` must be a valid VkViewportCoordinateSwizzleNV value

Possible values of the VkViewportSwizzleNV::`x`, `y`, `z`, and `w` members, specifying swizzling of the corresponding components of primitives, are:

    typedef enum VkViewportCoordinateSwizzleNV {
        VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_X_NV = 0,
        VK_VIEWPORT_COORDINATE_SWIZZLE_NEGATIVE_X_NV = 1,
        VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_Y_NV = 2,
        VK_VIEWPORT_COORDINATE_SWIZZLE_NEGATIVE_Y_NV = 3,
        VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_Z_NV = 4,
        VK_VIEWPORT_COORDINATE_SWIZZLE_NEGATIVE_Z_NV = 5,
        VK_VIEWPORT_COORDINATE_SWIZZLE_POSITIVE_W_NV = 6,
        VK_VIEWPORT_COORDINATE_SWIZZLE_NEGATIVE_W_NV = 7,
        VK_VIEWPORT_COORDINATE_SWIZZLE_MAX_ENUM_NV = 0x7FFFFFFF
    } VkViewportCoordinateSwizzleNV;

These values are described in detail in Viewport Swizzle.

### 25.3. Flat Shading

Flat shading a vertex output attribute means to assign all vertices of the primitive the same value for that output. The output values assigned are those of the provoking vertex of the primitive. Flat shading is applied to those vertex attributes that match fragment input attributes which are decorated as `Flat`.

If neither geometry nor tessellation shading is active, the provoking vertex is determined by the primitive topology defined by VkPipelineInputAssemblyStateCreateInfo:`topology` used to execute the drawing command.

If geometry shading is active, the provoking vertex is determined by the primitive topology defined by the `OutputPoints`, `OutputLineStrips`, or `OutputTriangleStrips` execution mode.

If tessellation shading is active but geometry shading is not, the provoking vertex may be any of the vertices in each primitive.

### 25.4. Primitive Clipping

Primitives are culled against the cull volume and then clipped to the clip volume. In clip coordinates, the view volume is defined by:

\[\begin{array}{c} -w_c \leq x_c \leq w_c \\ -w_c \leq y_c \leq w_c \\ 0 \leq z_c \leq w_c \end{array}\]

This view volume can be further restricted by as many as `VkPhysicalDeviceLimits`::`maxClipDistances` client-defined half-spaces.

The cull volume is the intersection of up to `VkPhysicalDeviceLimits`::`maxCullDistances` client-defined half-spaces (if no client-defined cull half-spaces are enabled, culling against the cull volume is skipped).

A shader must write a single cull distance for each enabled cull half-space to elements of the `CullDistance` array. If the cull distance for any enabled cull half-space is negative for all of the vertices of the primitive under consideration, the primitive is discarded. Otherwise the primitive is clipped against the clip volume as defined below.

The clip volume is the intersection of up to `VkPhysicalDeviceLimits`::`maxClipDistances` client-defined half-spaces with the view volume (if no client-defined clip half-spaces are enabled, the clip volume is the view volume).

A shader must write a single clip distance for each enabled clip half-space to elements of the `ClipDistance` array. Clip half-space i is then given by the set of points satisfying the inequality

  ci(P) ≥ 0

where ci(P) is the clip distance i at point P. For point primitives, ci(P) is simply the clip distance for the vertex in question. For line and triangle primitives, per-vertex clip distances are interpolated using a weighted mean, with weights derived according to the algorithms described in sections Basic Line Segment Rasterization and Basic Polygon Rasterization, using the perspective interpolation equations.

The number of client-defined clip and cull half-spaces that are enabled is determined by the explicit size of the built-in arrays `ClipDistance` and `CullDistance`, respectively, declared as an output in the interface of the entry point of the final shader stage before clipping.

If `VkPipelineRasterizationDepthClipStateCreateInfoEXT` is present in the graphics pipeline state then depth clipping is disabled if `VkPipelineRasterizationDepthClipStateCreateInfoEXT`::`depthClipEnable` is `VK_FALSE`. Otherwise, if `VkPipelineRasterizationDepthClipStateCreateInfoEXT` is not present, depth clipping is disabled when `VkPipelineRasterizationStateCreateInfo`::`depthClampEnable` is `VK_TRUE`. When depth clipping is disabled, the plane equation

  0 ≤ zc ≤ wc

(see the clip volume definition above) is ignored by view volume clipping (effectively, there is no near or far plane clipping).

If the primitive under consideration is a point or line segment, then clipping passes it unchanged if its vertices lie entirely within the clip volume.

Possible values of VkPhysicalDevicePointClippingProperties::`pointClippingBehavior`, specifying clipping behavior of a point primitive whose vertex lies outside the clip volume, are:

    typedef enum VkPointClippingBehavior {
        VK_POINT_CLIPPING_BEHAVIOR_ALL_CLIP_PLANES = 0,
        VK_POINT_CLIPPING_BEHAVIOR_USER_CLIP_PLANES_ONLY = 1,
        VK_POINT_CLIPPING_BEHAVIOR_ALL_CLIP_PLANES_KHR = VK_POINT_CLIPPING_BEHAVIOR_ALL_CLIP_PLANES,
        VK_POINT_CLIPPING_BEHAVIOR_USER_CLIP_PLANES_ONLY_KHR = VK_POINT_CLIPPING_BEHAVIOR_USER_CLIP_PLANES_ONLY,
        VK_POINT_CLIPPING_BEHAVIOR_MAX_ENUM = 0x7FFFFFFF
    } VkPointClippingBehavior;

or the equivalent

    typedef VkPointClippingBehavior VkPointClippingBehaviorKHR;

- `VK_POINT_CLIPPING_BEHAVIOR_ALL_CLIP_PLANES` specifies that the primitive is discarded if the vertex lies outside any clip plane, including the planes bounding the view volume.

- `VK_POINT_CLIPPING_BEHAVIOR_USER_CLIP_PLANES_ONLY` specifies that the primitive is discarded only if the vertex lies outside any user clip plane.

If either of a line segment’s vertices lie outside of the clip volume, the line segment may be clipped, with new vertex coordinates computed for each vertex that lies outside the clip volume. A clipped line segment endpoint lies on both the original line segment and the boundary of the clip volume.

This clipping produces a value, 0 ≤ t ≤ 1, for each clipped vertex. If the coordinates of a clipped vertex are P and the original vertices’ coordinates are P1 and P2, then t is given by

  P = t P1 + (1-t) P2.

| editing-note This is weird - it gives P, not t.

t is used to clip vertex output attributes as described in Clipping Shader Outputs.

If the primitive is a polygon, it passes unchanged if every one of its edges lie entirely inside the clip volume, and it is discarded if every one of its edges lie entirely outside the clip volume. If the edges of the polygon intersect the boundary of the clip volume, the intersecting edges are reconnected by new edges that lie along the boundary of the clip volume - in some cases requiring the introduction of new vertices into a polygon.

If a polygon intersects an edge of the clip volume’s boundary, the clipped polygon must include a point on this boundary edge.

Primitives rendered with user-defined half-spaces must satisfy a complementarity criterion. Suppose a series of primitives is drawn where each vertex i has a single specified clip distance di (or a number of similarly specified clip distances, if multiple half-spaces are enabled). Next, suppose that the same series of primitives are drawn again with each such clip distance replaced by -di (and the graphics pipeline is otherwise the same). In this case, primitives must not be missing any pixels, and pixels must not be drawn twice in regions where those primitives are cut by the clip planes.

### 25.5. Clipping Shader Outputs

Next, vertex output attributes are clipped. The output values associated with a vertex that lies within the clip volume are unaffected by clipping. If a primitive is clipped, however, the output values assigned to vertices produced by clipping are clipped.

Let the output values assigned to the two vertices P1 and P2 of an unclipped edge be c1 and c2. The value of t (see Primitive Clipping) for a clipped point P is used to obtain the output value associated with P as

  c = t c1 + (1-t) c2.

(Multiplying an output value by a scalar means multiplying each of x, y, z, and w by the scalar.)

Since this computation is performed in clip space before division by wc, clipped output values are perspective-correct.

Polygon clipping creates a clipped vertex along an edge of the clip volume’s boundary. This situation is handled by noting that polygon clipping proceeds by clipping against one half-space at a time. Output value clipping is done in the same way, so that clipped points always occur at the intersection of polygon edges (possibly already clipped) with the clip volume’s boundary.

For vertex output attributes whose matching fragment input attributes are decorated with `NoPerspective`, the value of t used to obtain the output value associated with P will be adjusted to produce results that vary linearly in framebuffer space.

Output attributes of integer or unsigned integer type must always be flat shaded. Flat shaded attributes are constant over the primitive being rasterized (see Basic Line Segment Rasterization and Basic Polygon Rasterization), and no interpolation is performed. The output value c is taken from either c1 or c2, since flat shading has already occurred and the two values are identical.

### 25.6. Controlling Viewport W Scaling

If viewport W scaling is enabled, the W component of the clip coordinate is modified by the provided coefficients from the corresponding viewport as follows.

  wc' = xcoeff xc + ycoeff yc + wc

The `VkPipelineViewportWScalingStateCreateInfoNV` structure is defined as:

    typedef struct VkPipelineViewportWScalingStateCreateInfoNV {
        VkStructureType                sType;
        const void*                    pNext;
        VkBool32                       viewportWScalingEnable;
        uint32_t                       viewportCount;
        const VkViewportWScalingNV*    pViewportWScalings;
    } VkPipelineViewportWScalingStateCreateInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `viewportWScalingEnable` controls whether viewport W scaling is enabled.

- `viewportCount` is the number of viewports used by W scaling, and must match the number of viewports in the pipeline if viewport W scaling is enabled.

- `pViewportWScalings` is a pointer to an array of `VkViewportWScalingNV` structures defining the W scaling parameters for the corresponding viewports. If the viewport W scaling state is dynamic, this member is ignored.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_W_SCALING_STATE_CREATE_INFO_NV`

- `viewportCount` must be greater than `0`

The `VkPipelineViewportWScalingStateCreateInfoNV` state is set by adding this structure to the `pNext` chain of a `VkPipelineViewportStateCreateInfo` structure and setting the graphics pipeline state with vkCreateGraphicsPipelines.

If the bound pipeline state object was not created with the `VK_DYNAMIC_STATE_VIEWPORT_W_SCALING_NV` dynamic state enabled, viewport W scaling parameters are specified using the `pViewportWScalings` member of VkPipelineViewportWScalingStateCreateInfoNV in the pipeline state object. If the pipeline state object was created with the `VK_DYNAMIC_STATE_VIEWPORT_W_SCALING_NV` dynamic state enabled, the viewport transformation parameters are dynamically set and changed with the command:

    void vkCmdSetViewportWScalingNV(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    firstViewport,
        uint32_t                                    viewportCount,
        const VkViewportWScalingNV*                 pViewportWScalings);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `firstViewport` is the index of the first viewport whose parameters are updated by the command.

- `viewportCount` is the number of viewports whose parameters are updated by the command.

- `pViewportWScalings` is a pointer to an array of VkViewportWScalingNV structures specifying viewport parameters.

The viewport parameters taken from element i of `pViewportWScalings` replace the current state for the viewport index `firstViewport` + i, for i in [0, `viewportCount`).

Valid Usage

- `firstViewport` must be less than VkPhysicalDeviceLimits::`maxViewports`

- The sum of `firstViewport` and `viewportCount` must be between `1` and VkPhysicalDeviceLimits::`maxViewports`, inclusive

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pViewportWScalings` must be a valid pointer to an array of `viewportCount` VkViewportWScalingNV structures

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- `viewportCount` must be greater than `0`

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics |

Both VkPipelineViewportWScalingStateCreateInfoNV and vkCmdSetViewportWScalingNV use `VkViewportWScalingNV` to set the viewport transformation parameters.

The `VkViewportWScalingNV` structure is defined as:

    typedef struct VkViewportWScalingNV {
        float    xcoeff;
        float    ycoeff;
    } VkViewportWScalingNV;

- `xcoeff` and `ycoeff` are the viewport’s W scaling factor for x and y respectively.

### 25.7. Coordinate Transformations

Clip coordinates for a vertex result from shader execution, which yields a vertex coordinate `Position`.

Perspective division on clip coordinates yields normalized device coordinates, followed by a viewport transformation (see Controlling the Viewport) to convert these coordinates into framebuffer coordinates.

If a vertex in clip coordinates has a position given by

\[\left(\begin{array}{c} x_c \\ y_c \\ z_c \\ w_c \end{array}\right)\]

then the vertex’s normalized device coordinates are

\[\left( \begin{array}{c} x_d \\ y_d \\ z_d \end{array} \right) = \left( \begin{array}{c} \frac{x_c}{w_c} \\ \frac{y_c}{w_c} \\ \frac{z_c}{w_c} \end{array} \right)\]

### 25.8. Render Pass Transform

A render pass transform can be can be enabled for render pass instances. The clip coordinates (xc, yc) that result from vertex shader execution are transformed by a rotation of of 0, 90, 180, or 270 degrees in the XY plane, centered at the origin.

When Render pass transform is enabled, the transform applies to all primitives for all subpasses of the render pass. The transformed vertex in in clip coordinates has a position given by

\[\left( \begin{array}{c} x_{c_{trans}} \\ y_{c_{trans}} \\ z_{c_{trans}} \end{array} \right) = \left( \begin{array}{c} x_{c} \cos \theta - y_{c} \sin \theta \\ x_{c} \sin \theta + y_{c} \cos \theta \\ z_c \end{array} \right)\]

where

- θ is 0 degrees for VK_SURFACE_TRANSFORM_IDENTITY_BIT_KHR

- θ is 90 degrees for VK_SURFACE_TRANSFORM_ROTATE_90_BIT_KHR

- θ is 180 degrees for VK_SURFACE_TRANSFORM_ROTATE_180_BIT_KHR

- θ is 270 degrees for VK_SURFACE_TRANSFORM_ROTATE_270_BIT_KHR

The transformed vertex’s normalized device coordinates are

\[\left( \begin{array}{c} x_d \\ y_d \\ z_d \end{array} \right) = \left( \begin{array}{c} \frac{x_{c_{trans}}}{w_c} \\ \frac{y_{c_{trans}}}{w_c} \\ \frac{z_{c_{trans}}}{w_c} \end{array} \right)\]

When render pass transform is enabled for a renderpass instance, the following additional features are enabled:

- Each VkViewport specified by either VkPipelineViewportStateCreateInfo::`pViewports` or vkCmdSetViewport will have its width/height (px, py) and its center (ox, oy) similarly transformed by the implementation.

- Each scissor specified by VkPipelineViewportStateCreateInfo::`pScissors` or vkCmdSetScissor will have it’s (offsetx, offsety) and (extentx, extenty) similarly transformed by the implementation.

- The `renderArea` specified in VkCommandBufferInheritanceRenderPassTransformInfoQCOM and sink:VkRenderPassBeginInfo will be similarly transformed by the implementation.

- The (x, y) components of shader variables with built-in decorations `FragCoord`, `SamplePosition`, or `PointCoord` will be similarly transformed by the implementation.

- The (x,y) components of the `offset` operand of the `InterpolateAtOffset` extended instruction will be similarly transformed by the implementation.

- The values returned by SPIR-V derivative instructions `OpDPdx`, `OpDPdy`, `OpDPdxCourse`, `OpDPdyCourse`, `OpDPdxFine`, `OpDPdyFine` will be similarly transformed by the implementation.

The net result of the above, is that applications can act as if the rendering to a framebuffer oriented with the VkSurfaceCapabilitiesKHR::`currentTransform`, as if the presentation engine will performing the transformation of the swapchain image after rendering and prior to presentation to the user. In fact, the transformation of the various items cited above are being handled by the implementation as the rendering takes place.

### 25.9. Controlling the Viewport

The viewport transformation is determined by the selected viewport’s width and height in pixels, px and py, respectively, and its center (ox, oy) (also in pixels), as well as its depth range min and max determining a depth range scale value pz and a depth range bias value oz (defined below). The vertex’s framebuffer coordinates (xf, yf, zf) are given by

  xf = (px / 2) xd + ox

  yf = (py / 2) yd + oy

  zf = pz × zd + oz

Multiple viewports are available, numbered zero up to `VkPhysicalDeviceLimits`::`maxViewports` minus one. The number of viewports used by a pipeline is controlled by the `viewportCount` member of the `VkPipelineViewportStateCreateInfo` structure used in pipeline creation.

The `VkPipelineViewportStateCreateInfo` structure is defined as:

    typedef struct VkPipelineViewportStateCreateInfo {
        VkStructureType                       sType;
        const void*                           pNext;
        VkPipelineViewportStateCreateFlags    flags;
        uint32_t                              viewportCount;
        const VkViewport*                     pViewports;
        uint32_t                              scissorCount;
        const VkRect2D*                       pScissors;
    } VkPipelineViewportStateCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `viewportCount` is the number of viewports used by the pipeline.

- `pViewports` is a pointer to an array of VkViewport structures, defining the viewport transforms. If the viewport state is dynamic, this member is ignored.

- `scissorCount` is the number of scissors and must match the number of viewports.

- `pScissors` is a pointer to an array of VkRect2D structures defining the rectangular bounds of the scissor for the corresponding viewport. If the scissor state is dynamic, this member is ignored.

Valid Usage

- If the multiple viewports feature is not enabled, `viewportCount` must be `1`

- If the multiple viewports feature is not enabled, `scissorCount` must be `1`

- `viewportCount` must be between `1` and `VkPhysicalDeviceLimits`::`maxViewports`, inclusive

- `scissorCount` must be between `1` and `VkPhysicalDeviceLimits`::`maxViewports`, inclusive

- `scissorCount` and `viewportCount` must be identical

- The `x` and `y` members of `offset` member of any element of `pScissors` must be greater than or equal to `0`

- Evaluation of (`offset.x` + `extent.width`) must not cause a signed integer addition overflow for any element of `pScissors`

- Evaluation of (`offset.y` + `extent.height`) must not cause a signed integer addition overflow for any element of `pScissors`

- If the `viewportWScalingEnable` member of a VkPipelineViewportWScalingStateCreateInfoNV structure included in the `pNext` chain is `VK_TRUE`, the `viewportCount` member of the VkPipelineViewportWScalingStateCreateInfoNV structure must be equal to `viewportCount`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkPipelineViewportCoarseSampleOrderStateCreateInfoNV, VkPipelineViewportExclusiveScissorStateCreateInfoNV, VkPipelineViewportShadingRateImageStateCreateInfoNV, VkPipelineViewportSwizzleStateCreateInfoNV, or VkPipelineViewportWScalingStateCreateInfoNV

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be `0`

- `viewportCount` must be greater than `0`

- `scissorCount` must be greater than `0`

    typedef VkFlags VkPipelineViewportStateCreateFlags;

`VkPipelineViewportStateCreateFlags` is a bitmask type for setting a mask, but is currently reserved for future use.

A vertex processing stage can direct each primitive to zero or more viewports. The destination viewports for a primitive are selected by the last active vertex processing stage that has an output variable decorated with `ViewportIndex` (selecting a single viewport) or `ViewportMaskNV` (selecting multiple viewports). The viewport transform uses the viewport corresponding to either the value assigned to `ViewportIndex` or one of the bits set in `ViewportMaskNV`, and taken from an implementation-dependent vertex of each primitive. If `ViewportIndex` or any of the bits in `ViewportMaskNV` are outside the range zero to `viewportCount` minus one for a primitive, or if the last active vertex processing stage did not assign a value to either `ViewportIndex` or `ViewportMaskNV` for all vertices of a primitive due to flow control, the values resulting from the viewport transformation of the vertices of such primitives are undefined. If the last vertex processing stage does not have an output decorated with `ViewportIndex` or `ViewportMaskNV`, the viewport numbered zero is used by the viewport transformation.

A single vertex can be used in more than one individual primitive, in primitives such as `VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP`. In this case, the viewport transformation is applied separately for each primitive.

If the bound pipeline state object was not created with the `VK_DYNAMIC_STATE_VIEWPORT` dynamic state enabled, viewport transformation parameters are specified using the `pViewports` member of `VkPipelineViewportStateCreateInfo` in the pipeline state object. If the pipeline state object was created with the `VK_DYNAMIC_STATE_VIEWPORT` dynamic state enabled, the viewport transformation parameters are dynamically set and changed with the command:

    void vkCmdSetViewport(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    firstViewport,
        uint32_t                                    viewportCount,
        const VkViewport*                           pViewports);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `firstViewport` is the index of the first viewport whose parameters are updated by the command.

- `viewportCount` is the number of viewports whose parameters are updated by the command.

- `pViewports` is a pointer to an array of VkViewport structures specifying viewport parameters.

The viewport parameters taken from element i of `pViewports` replace the current state for the viewport index `firstViewport` + i, for i in [0, `viewportCount`).

Valid Usage

- `firstViewport` must be less than `VkPhysicalDeviceLimits`::`maxViewports`

- The sum of `firstViewport` and `viewportCount` must be between `1` and `VkPhysicalDeviceLimits`::`maxViewports`, inclusive

- If the multiple viewports feature is not enabled, `firstViewport` must be `0`

- If the multiple viewports feature is not enabled, `viewportCount` must be `1`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pViewports` must be a valid pointer to an array of `viewportCount` valid VkViewport structures

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- `viewportCount` must be greater than `0`

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics |

Both VkPipelineViewportStateCreateInfo and vkCmdSetViewport use `VkViewport` to set the viewport transformation parameters.

The `VkViewport` structure is defined as:

    typedef struct VkViewport {
        float    x;
        float    y;
        float    width;
        float    height;
        float    minDepth;
        float    maxDepth;
    } VkViewport;

- `x` and `y` are the viewport’s upper left corner (x,y).

- `width` and `height` are the viewport’s width and height, respectively.

- `minDepth` and `maxDepth` are the depth range for the viewport. It is valid for `minDepth` to be greater than or equal to `maxDepth`.

The framebuffer depth coordinate `z`f may be represented using either a fixed-point or floating-point representation. However, a floating-point representation must be used if the depth/stencil attachment has a floating-point depth component. If an m-bit fixed-point representation is used, we assume that it represents each value \(\frac{k}{2^m - 1}\), where k ∈ { 0, 1, …​, 2m-1 }, as k (e.g. 1.0 is represented in binary as a string of all ones).

The viewport parameters shown in the above equations are found from these values as

  ox = `x` + `width` / 2

  oy = `y` + `height` / 2

  oz = `minDepth`

  px = `width`

  py = `height`

  pz = `maxDepth` - `minDepth`.

If a render pass transform is enabled, the values (px,py) and (ox, oy) defining the viewport are transformed as described in render pass transform before participating in the viewport transform.

The application can specify a negative term for `height`, which has the effect of negating the y coordinate in clip space before performing the transform. When using a negative `height`, the application should also adjust the `y` value to point to the lower left corner of the viewport instead of the upper left corner. Using the negative `height` allows the application to avoid having to negate the y component of the `Position` output from the last vertex processing stage in shaders that also target other graphics APIs.

The width and height of the implementation-dependent maximum viewport dimensions must be greater than or equal to the width and height of the largest image which can be created and attached to a framebuffer.

The floating-point viewport bounds are represented with an implementation-dependent precision.

Valid Usage

- `width` must be greater than `0.0`

- `width` must be less than or equal to `VkPhysicalDeviceLimits`::`maxViewportDimensions`[0]

- The absolute value of `height` must be less than or equal to `VkPhysicalDeviceLimits`::`maxViewportDimensions`[1]

- `x` must be greater than or equal to `viewportBoundsRange`[0]

- (`x` + `width`) must be less than or equal to `viewportBoundsRange`[1]

- `y` must be greater than or equal to `viewportBoundsRange`[0]

- `y` must be less than or equal to `viewportBoundsRange`[1]

- (`y` + `height`) must be greater than or equal to `viewportBoundsRange`[0]

- (`y` + `height`) must be less than or equal to `viewportBoundsRange`[1]

- Unless `VK_EXT_depth_range_unrestricted` extension is enabled `minDepth` must be between `0.0` and `1.0`, inclusive

- Unless `VK_EXT_depth_range_unrestricted` extension is enabled `maxDepth` must be between `0.0` and `1.0`, inclusive

## 26. Rasterization

Rasterization is the process by which a primitive is converted to a two-dimensional image. Each point of this image contains associated data such as depth, color, or other attributes.

Rasterizing a primitive begins by determining which squares of an integer grid in framebuffer coordinates are occupied by the primitive, and assigning one or more depth values to each such square. This process is described below for points, lines, and polygons.

A grid square, including its (x,y) framebuffer coordinates, z (depth), and associated data added by fragment shaders, is called a fragment. A fragment is located by its upper left corner, which lies on integer grid coordinates.

Rasterization operations also refer to a fragment’s sample locations, which are offset by fractional values from its upper left corner. The rasterization rules for points, lines, and triangles involve testing whether each sample location is inside the primitive. Fragments need not actually be square, and rasterization rules are not affected by the aspect ratio of fragments. Display of non-square grids, however, will cause rasterized points and line segments to appear fatter in one direction than the other.

We assume that fragments are square, since it simplifies antialiasing and texturing. After rasterization, fragments are processed by the early per-fragment tests, if enabled.

Several factors affect rasterization, including the members of `VkPipelineRasterizationStateCreateInfo` and `VkPipelineMultisampleStateCreateInfo`.

The `VkPipelineRasterizationStateCreateInfo` structure is defined as:

    typedef struct VkPipelineRasterizationStateCreateInfo {
        VkStructureType                            sType;
        const void*                                pNext;
        VkPipelineRasterizationStateCreateFlags    flags;
        VkBool32                                   depthClampEnable;
        VkBool32                                   rasterizerDiscardEnable;
        VkPolygonMode                              polygonMode;
        VkCullModeFlags                            cullMode;
        VkFrontFace                                frontFace;
        VkBool32                                   depthBiasEnable;
        float                                      depthBiasConstantFactor;
        float                                      depthBiasClamp;
        float                                      depthBiasSlopeFactor;
        float                                      lineWidth;
    } VkPipelineRasterizationStateCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `depthClampEnable` controls whether to clamp the fragment’s depth values as described in Depth Test. If the pipeline is not created with VkPipelineRasterizationDepthClipStateCreateInfoEXT present then enabling depth clamp will also disable clipping primitives to the z planes of the frustrum as described in Primitive Clipping. Otherwise depth clipping is controlled by the state set in `VkPipelineRasterizationDepthClipStateCreateInfoEXT`.

- `rasterizerDiscardEnable` controls whether primitives are discarded immediately before the rasterization stage.

- `polygonMode` is the triangle rendering mode. See VkPolygonMode.

- `cullMode` is the triangle facing direction used for primitive culling. See VkCullModeFlagBits.

- `frontFace` is a VkFrontFace value specifying the front-facing triangle orientation to be used for culling.

- `depthBiasEnable` controls whether to bias fragment depth values.

- `depthBiasConstantFactor` is a scalar factor controlling the constant depth value added to each fragment.

- `depthBiasClamp` is the maximum (or minimum) depth bias of a fragment.

- `depthBiasSlopeFactor` is a scalar factor applied to a fragment’s slope in depth bias calculations.

- `lineWidth` is the width of rasterized line segments.

The application can also add a `VkPipelineRasterizationStateRasterizationOrderAMD` structure to the `pNext` chain of a `VkPipelineRasterizationStateCreateInfo` structure. This structure enables selecting the rasterization order to use when rendering with the corresponding graphics pipeline as described in Rasterization Order.

Valid Usage

- If the depth clamping feature is not enabled, `depthClampEnable` must be `VK_FALSE`

- If the non-solid fill modes feature is not enabled, `polygonMode` must be `VK_POLYGON_MODE_FILL` or `VK_POLYGON_MODE_FILL_RECTANGLE_NV`

- If the `VK_NV_fill_rectangle` extension is not enabled, `polygonMode` must not be `VK_POLYGON_MODE_FILL_RECTANGLE_NV`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_CREATE_INFO`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkPipelineRasterizationConservativeStateCreateInfoEXT, VkPipelineRasterizationDepthClipStateCreateInfoEXT, VkPipelineRasterizationLineStateCreateInfoEXT, VkPipelineRasterizationStateRasterizationOrderAMD, or VkPipelineRasterizationStateStreamCreateInfoEXT

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be `0`

- `polygonMode` must be a valid VkPolygonMode value

- `cullMode` must be a valid combination of VkCullModeFlagBits values

- `frontFace` must be a valid VkFrontFace value

    typedef VkFlags VkPipelineRasterizationStateCreateFlags;

`VkPipelineRasterizationStateCreateFlags` is a bitmask type for setting a mask, but is currently reserved for future use.

If the pNext chain of VkPipelineRasterizationStateCreateInfo includes a `VkPipelineRasterizationDepthClipStateCreateInfoEXT` structure, then that structure controls whether depth clipping is enabled or disabled.

The `VkPipelineRasterizationDepthClipStateCreateInfoEXT` structure is defined as:

    typedef struct VkPipelineRasterizationDepthClipStateCreateInfoEXT {
        VkStructureType                                        sType;
        const void*                                            pNext;
        VkPipelineRasterizationDepthClipStateCreateFlagsEXT    flags;
        VkBool32                                               depthClipEnable;
    } VkPipelineRasterizationDepthClipStateCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `depthClipEnable` controls whether depth clipping is enabled as described in Primitive Clipping.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_DEPTH_CLIP_STATE_CREATE_INFO_EXT`

- `flags` must be `0`

    typedef VkFlags VkPipelineRasterizationDepthClipStateCreateFlagsEXT;

`VkPipelineRasterizationDepthClipStateCreateFlagsEXT` is a bitmask type for setting a mask, but is currently reserved for future use.

The `VkPipelineMultisampleStateCreateInfo` structure is defined as:

    typedef struct VkPipelineMultisampleStateCreateInfo {
        VkStructureType                          sType;
        const void*                              pNext;
        VkPipelineMultisampleStateCreateFlags    flags;
        VkSampleCountFlagBits                    rasterizationSamples;
        VkBool32                                 sampleShadingEnable;
        float                                    minSampleShading;
        const VkSampleMask*                      pSampleMask;
        VkBool32                                 alphaToCoverageEnable;
        VkBool32                                 alphaToOneEnable;
    } VkPipelineMultisampleStateCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `rasterizationSamples` is a VkSampleCountFlagBits specifying the number of samples used in rasterization.

- `sampleShadingEnable` can be used to enable Sample Shading.

- `minSampleShading` specifies a minimum fraction of sample shading if `sampleShadingEnable` is set to `VK_TRUE`.

- `pSampleMask` is a bitmask of static coverage information that is ANDed with the coverage information generated during rasterization, as described in Sample Mask.

- `alphaToCoverageEnable` controls whether a temporary coverage value is generated based on the alpha component of the fragment’s first color output as specified in the Multisample Coverage section.

- `alphaToOneEnable` controls whether the alpha component of the fragment’s first color output is replaced with one as described in Multisample Coverage.

Valid Usage

- If the sample rate shading feature is not enabled, `sampleShadingEnable` must be `VK_FALSE`

- If the alpha to one feature is not enabled, `alphaToOneEnable` must be `VK_FALSE`

- `minSampleShading` must be in the range [0,1]

- If the `VK_NV_framebuffer_mixed_samples` extension is enabled, and if the subpass has any color attachments and `rasterizationSamples` is greater than the number of color samples, then `sampleShadingEnable` must be `VK_FALSE`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_MULTISAMPLE_STATE_CREATE_INFO`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkPipelineCoverageModulationStateCreateInfoNV, VkPipelineCoverageReductionStateCreateInfoNV, VkPipelineCoverageToColorStateCreateInfoNV, or VkPipelineSampleLocationsStateCreateInfoEXT

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be `0`

- `rasterizationSamples` must be a valid VkSampleCountFlagBits value

- If `pSampleMask` is not `NULL`, `pSampleMask` must be a valid pointer to an array of \(\lceil{\mathit{rasterizationSamples} \over 32}\rceil\) `VkSampleMask` values

    typedef VkFlags VkPipelineMultisampleStateCreateFlags;

`VkPipelineMultisampleStateCreateFlags` is a bitmask type for setting a mask, but is currently reserved for future use.

Rasterization only generates fragments which cover one or more pixels inside the framebuffer. Pixels outside the framebuffer are never considered covered in the fragment. Fragments which would be produced by application of any of the primitive rasterization rules described below but which lie outside the framebuffer are not produced, nor are they processed by any later stage of the pipeline, including any of the early per-fragment tests described in Early Per-Fragment Tests.

Surviving fragments are processed by fragment shaders. Fragment shaders determine associated data for fragments, and can also modify or replace their assigned depth values.

When the `VK_AMD_mixed_attachment_samples` and `VK_NV_framebuffer_mixed_samples` extensions are not enabled, if the subpass for which this pipeline is being created uses color and/or depth/stencil attachments, then `rasterizationSamples` must be the same as the sample count for those subpass attachments.

When the `VK_AMD_mixed_attachment_samples` extension is enabled, if the subpass for which this pipeline is being created uses color and/or depth/stencil attachments, then `rasterizationSamples` must be the same as the maximum of the sample counts of those subpass attachments.

When the `VK_NV_framebuffer_mixed_samples` extension is enabled, `rasterizationSamples` must match the sample count of the depth/stencil attachment if present, otherwise must be greater than or equal to the sample count of the color attachments, if present.

If the `VK_NV_coverage_reduction_mode` extension is enabled, the coverage reduction mode specified by VkPipelineCoverageReductionStateCreateInfoNV::`coverageReductionMode`, the `rasterizationSamples` member of `pMultisampleState` and the sample counts for the color and depth/stencil attachments (if present) must be a valid combination returned by `vkGetPhysicalDeviceSupportedFramebufferMixedSamplesCombinationsNV`

If the subpass for which this pipeline is being created does not use color or depth/stencil attachments, `rasterizationSamples` must follow the rules for a zero-attachment subpass.

### 26.1. Discarding Primitives Before Rasterization

Primitives are discarded before rasterization if the `rasterizerDiscardEnable` member of VkPipelineRasterizationStateCreateInfo is enabled. When enabled, primitives are discarded after they are processed by the last active shader stage in the pipeline before rasterization.

### 26.2. Controlling the Vertex Stream Used for Rasterization

By default vertex data output from the last vertex processing stage are directed to vertex stream zero. Geometry shaders can emit primitives to multiple independent vertex streams. Each vertex emitted by the geometry shader is directed at one of the vertex streams. As vertices are received on each vertex stream, they are arranged into primitives of the type specified by the geometry shader output primitive type. The shading language instructions `OpEndPrimitive` and `OpEndStreamPrimitive` can be used to end the primitive being assembled on a given vertex stream and start a new empty primitive of the same type. An implementation supports up to `VkPhysicalDeviceTransformFeedbackPropertiesEXT`::`maxTransformFeedbackStreams` streams, which is at least 1. The individual streams are numbered 0 through `maxTransformFeedbackStreams` minus 1. There is no requirement on the order of the streams to which vertices are emitted, and the number of vertices emitted to each vertex stream can be completely independent, subject only to the `VkPhysicalDeviceTransformFeedbackPropertiesEXT`::`maxTransformFeedbackStreamDataSize` and `VkPhysicalDeviceTransformFeedbackPropertiesEXT`::`maxTransformFeedbackBufferDataSize` limits. The primitives output from all vertex streams are passed to the transform feedback stage to be captured to transform feedback buffers in the manner specified by the last vertex processing stage shader’s `XfbBuffer`, `XfbStride`, and `Offsets` decorations on the output interface variables in the graphics pipeline. To use a vertex stream other than zero, or to use multiple streams, the `GeometryStreams` capability must be specified.

By default, the primitives output from vertex stream zero are rasterized. If the implementation supports the VkPhysicalDeviceTransformFeedbackPropertiesEXT::`transformFeedbackRasterizationStreamSelect` property it is possible to rasterize a vertex stream other than zero.

By default, geometry shaders that emit vertices to multiple vertex streams are limited to using only the `OutputPoints` output primitive type. If the implementation supports the VkPhysicalDeviceTransformFeedbackPropertiesEXT::`transformFeedbackStreamsLinesTriangles` property it is possible to emit `OutputLineStrip` or `OutputTriangleStrip` in addition to `OutputPoints`.

The vertex stream used for rasterization is specified by adding a `VkPipelineRasterizationStateStreamCreateInfoEXT` structure to the `pNext` chain of a VkPipelineRasterizationStateCreateInfo structure.

The `VkPipelineRasterizationStateStreamCreateInfoEXT` structure is defined as:

    typedef struct VkPipelineRasterizationStateStreamCreateInfoEXT {
        VkStructureType                                     sType;
        const void*                                         pNext;
        VkPipelineRasterizationStateStreamCreateFlagsEXT    flags;
        uint32_t                                            rasterizationStream;
    } VkPipelineRasterizationStateStreamCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `rasterizationStream` is the vertex stream selected for rasterization.

If this structure is not present, `rasterizationStream` is assumed to be zero.

Valid Usage

- `VkPhysicalDeviceTransformFeedbackFeaturesEXT`::`geometryStreams` must be enabled

- `rasterizationStream` must be less than VkPhysicalDeviceTransformFeedbackPropertiesEXT::`maxTransformFeedbackStreams`

- `rasterizationStream` must be zero if `VkPhysicalDeviceTransformFeedbackPropertiesEXT`::`transformFeedbackRasterizationStreamSelect` is `VK_FALSE`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_STREAM_CREATE_INFO_EXT`

- `flags` must be `0`

    typedef VkFlags VkPipelineRasterizationStateStreamCreateFlagsEXT;

`VkPipelineRasterizationStateStreamCreateFlagsEXT` is a bitmask type for setting a mask, but is currently reserved for future use.

### 26.3. Rasterization Order

Within a subpass of a render pass instance, for a given (x,y,layer,sample) sample location, the following operations are guaranteed to execute in rasterization order, for each separate primitive that includes that sample location:

1. Scissor test

2. Exclusive scissor test

3. Sample mask generation

4. Depth bounds test

5. Stencil test, stencil op and stencil write

6. Depth test and depth write

7. Sample counting for occlusion queries

8. Fragment Coverage To Color

9. coverage reduction

10. Blending, logic operations, and color writes

Each of these operations is atomically executed for each primitive and sample location.

Execution of these operations for each primitive in a subpass occurs in an order determined by the application.

The rasterization order to use for a graphics pipeline is specified by adding a `VkPipelineRasterizationStateRasterizationOrderAMD` structure to the `pNext` chain of a VkPipelineRasterizationStateCreateInfo structure.

The `VkPipelineRasterizationStateRasterizationOrderAMD` structure is defined as:

    typedef struct VkPipelineRasterizationStateRasterizationOrderAMD {
        VkStructureType            sType;
        const void*                pNext;
        VkRasterizationOrderAMD    rasterizationOrder;
    } VkPipelineRasterizationStateRasterizationOrderAMD;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `rasterizationOrder` is a VkRasterizationOrderAMD value specifying the primitive rasterization order to use.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_RASTERIZATION_ORDER_AMD`

- `rasterizationOrder` must be a valid VkRasterizationOrderAMD value

If the `VK_AMD_rasterization_order` device extension is not enabled or the application does not request a particular rasterization order through specifying a `VkPipelineRasterizationStateRasterizationOrderAMD` structure then the rasterization order used by the graphics pipeline defaults to `VK_RASTERIZATION_ORDER_STRICT_AMD`.

Possible values of VkPipelineRasterizationStateRasterizationOrderAMD::`rasterizationOrder`, specifying the primitive rasterization order, are:

    typedef enum VkRasterizationOrderAMD {
        VK_RASTERIZATION_ORDER_STRICT_AMD = 0,
        VK_RASTERIZATION_ORDER_RELAXED_AMD = 1,
        VK_RASTERIZATION_ORDER_MAX_ENUM_AMD = 0x7FFFFFFF
    } VkRasterizationOrderAMD;

- `VK_RASTERIZATION_ORDER_STRICT_AMD` specifies that operations for each primitive in a subpass must occur in primitive order.

- `VK_RASTERIZATION_ORDER_RELAXED_AMD` specifies that operations for each primitive in a subpass may not occur in primitive order.

### 26.4. Multisampling

Multisampling is a mechanism to antialias all Vulkan primitives: points, lines, and polygons. The technique is to sample all primitives multiple times at each pixel. Each sample in each framebuffer attachment has storage for a color, depth, and/or stencil value, such that per-fragment operations apply to each sample independently. The color sample values can be later resolved to a single color (see Resolving Multisample Images and the Render Pass chapter for more details on how to resolve multisample images to non-multisample images).

Vulkan defines rasterization rules for single-sample modes in a way that is equivalent to a multisample mode with a single sample in the center of each fragment.

Each fragment includes a coverage value with `rasterizationSamples` bits (see Sample Mask). Each fragment includes `rasterizationSamples` depth values and sets of associated data. An implementation may choose to assign the same associated data to more than one sample. The location for evaluating such associated data may be anywhere within the fragment area including the fragment’s center location (xf,yf) or any of the sample locations. When `rasterizationSamples` is `VK_SAMPLE_COUNT_1_BIT`, the fragment’s center location must be used. The different associated data values need not all be evaluated at the same location. Each fragment thus consists of integer x and y grid coordinates, `rasterizationSamples` depth values and sets of associated data, and a coverage value with `rasterizationSamples` bits.

It is understood that each pixel has `rasterizationSamples` locations associated with it. These locations are exact positions, rather than regions or areas, and each is referred to as a sample point. The sample points associated with a pixel must be located inside or on the boundary of the unit square that is considered to bound the pixel. Furthermore, the relative locations of sample points may be identical for each pixel in the framebuffer, or they may differ.

If the render pass has a fragment density map attachment, each fragment only has `rasterizationSamples` locations associated with it regardless of how many pixels are covered in the fragment area. Fragment sample locations are defined as if the fragment had an area of (1,1) and its sample points must be located within these bounds. Their actual location in the framebuffer is calculated by scaling the sample location by the fragment area. Attachments with storage for multiple samples per pixel are located at the pixel sample locations. Otherwise, the fragment’s sample locations are generally used for evaluation of associated data and fragment operations.

If the current pipeline includes a fragment shader with one or more variables in its interface decorated with `Sample` and `Input`, the data associated with those variables will be assigned independently for each sample. The values for each sample must be evaluated at the location of the sample. The data associated with any other variables not decorated with `Sample` and `Input` need not be evaluated independently for each sample.

If the `standardSampleLocations` member of VkPhysicalDeviceLimits is `VK_TRUE`, then the sample counts `VK_SAMPLE_COUNT_1_BIT`, `VK_SAMPLE_COUNT_2_BIT`, `VK_SAMPLE_COUNT_4_BIT`, `VK_SAMPLE_COUNT_8_BIT`, and `VK_SAMPLE_COUNT_16_BIT` have sample locations as listed in the following table, with the ith entry in the table corresponding to bit i in the sample masks. `VK_SAMPLE_COUNT_32_BIT` and `VK_SAMPLE_COUNT_64_BIT` do not have standard sample locations. Locations are defined relative to an origin in the upper left corner of the fragment.

Table 31. Standard sample locations
`VK_SAMPLE_COUNT_1_BIT` | `VK_SAMPLE_COUNT_2_BIT` | `VK_SAMPLE_COUNT_4_BIT` | `VK_SAMPLE_COUNT_8_BIT` | `VK_SAMPLE_COUNT_16_BIT`
(0.5,0.5) | (0.75,0.75) (0.25,0.25) | (0.375, 0.125) (0.875, 0.375) (0.125, 0.625) (0.625, 0.875) | (0.5625, 0.3125) (0.4375, 0.6875) (0.8125, 0.5625) (0.3125, 0.1875) (0.1875, 0.8125) (0.0625, 0.4375) (0.6875, 0.9375) (0.9375, 0.0625) | (0.5625, 0.5625) (0.4375, 0.3125) (0.3125, 0.625) (0.75, 0.4375) (0.1875, 0.375) (0.625, 0.8125) (0.8125, 0.6875) (0.6875, 0.1875) (0.375, 0.875) (0.5, 0.0625) (0.25, 0.125) (0.125, 0.75) (0.0, 0.5) (0.9375, 0.25) (0.875, 0.9375) (0.0625, 0.0)

Color images created with multiple samples per pixel use a compression technique where there are two arrays of data associated with each pixel. The first array contains one element per sample where each element stores an index to the second array defining the fragment mask of the pixel. The second array contains one element per color fragment and each element stores a unique color value in the format of the image. With this compression technique it is not always necessary to actually use unique storage locations for each color sample: when multiple samples share the same color value the fragment mask may have two samples referring to the same color fragment. The number of color fragments is determined by the `samples` member of the VkImageCreateInfo structure used to create the image. The `VK_AMD_shader_fragment_mask` device extension provides shader instructions enabling the application to get direct access to the fragment mask and the individual color fragment values.

Figure 16. Fragment Mask

### 26.5. Custom Sample Locations

Applications can also control the sample locations used for rasterization.

If the `pNext` chain of the VkPipelineMultisampleStateCreateInfo structure specified at pipeline creation time includes a `VkPipelineSampleLocationsStateCreateInfoEXT` structure, then that structure controls the sample locations used when rasterizing primitives with the pipeline.

The `VkPipelineSampleLocationsStateCreateInfoEXT` structure is defined as:

    typedef struct VkPipelineSampleLocationsStateCreateInfoEXT {
        VkStructureType             sType;
        const void*                 pNext;
        VkBool32                    sampleLocationsEnable;
        VkSampleLocationsInfoEXT    sampleLocationsInfo;
    } VkPipelineSampleLocationsStateCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `sampleLocationsEnable` controls whether custom sample locations are used. If `sampleLocationsEnable` is `VK_FALSE`, the default sample locations are used and the values specified in `sampleLocationsInfo` are ignored.

- `sampleLocationsInfo` is the sample locations to use during rasterization if `sampleLocationsEnable` is `VK_TRUE` and the graphics pipeline is not created with `VK_DYNAMIC_STATE_SAMPLE_LOCATIONS_EXT`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_SAMPLE_LOCATIONS_STATE_CREATE_INFO_EXT`

- `sampleLocationsInfo` must be a valid VkSampleLocationsInfoEXT structure

The `VkSampleLocationsInfoEXT` structure is defined as:

    typedef struct VkSampleLocationsInfoEXT {
        VkStructureType               sType;
        const void*                   pNext;
        VkSampleCountFlagBits         sampleLocationsPerPixel;
        VkExtent2D                    sampleLocationGridSize;
        uint32_t                      sampleLocationsCount;
        const VkSampleLocationEXT*    pSampleLocations;
    } VkSampleLocationsInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `sampleLocationsPerPixel` is a VkSampleCountFlagBits specifying the number of sample locations per pixel.

- `sampleLocationGridSize` is the size of the sample location grid to select custom sample locations for.

- `sampleLocationsCount` is the number of sample locations in `pSampleLocations`.

- `pSampleLocations` is a pointer to an array of `sampleLocationsCount` VkSampleLocationEXT structures.

This structure can be used either to specify the sample locations to be used for rendering or to specify the set of sample locations an image subresource has been last rendered with for the purposes of layout transitions of depth/stencil images created with `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT`.

The sample locations in `pSampleLocations` specify `sampleLocationsPerPixel` number of sample locations for each pixel in the grid of the size specified in `sampleLocationGridSize`. The sample location for sample i at the pixel grid location (x,y) is taken from `pSampleLocations`[(x + y * `sampleLocationGridSize.width`) * `sampleLocationsPerPixel` + i].

If the render pass has a fragment density map, the implementation will choose the sample locations for the fragment and the contents of `pSampleLocations` may be ignored.

Valid Usage

- `sampleLocationsPerPixel` must be a bit value that is set in VkPhysicalDeviceSampleLocationsPropertiesEXT::`sampleLocationSampleCounts`

- `sampleLocationsCount` must equal `sampleLocationsPerPixel` × `sampleLocationGridSize.width` × `sampleLocationGridSize.height`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SAMPLE_LOCATIONS_INFO_EXT`

- If `sampleLocationsPerPixel` is not `0`, `sampleLocationsPerPixel` must be a valid VkSampleCountFlagBits value

- If `sampleLocationsCount` is not `0`, `pSampleLocations` must be a valid pointer to an array of `sampleLocationsCount` VkSampleLocationEXT structures

The `VkSampleLocationEXT` structure is defined as:

    typedef struct VkSampleLocationEXT {
        float    x;
        float    y;
    } VkSampleLocationEXT;

- `x` is the horizontal coordinate of the sample’s location.

- `y` is the vertical coordinate of the sample’s location.

The domain space of the sample location coordinates has an upper-left origin within the pixel in framebuffer space.

The values specified in a `VkSampleLocationEXT` structure are always clamped to the implementation-dependent sample location coordinate range [`sampleLocationCoordinateRange`[0],`sampleLocationCoordinateRange`[1]] that can be queried by adding a VkPhysicalDeviceSampleLocationsPropertiesEXT structure to the `pNext` chain of VkPhysicalDeviceProperties2.

The custom sample locations used for rasterization when `VkPipelineSampleLocationsStateCreateInfoEXT`::`sampleLocationsEnable` is `VK_TRUE` are specified by the `VkPipelineSampleLocationsStateCreateInfoEXT`::`sampleLocationsInfo` property of the bound graphics pipeline, if the pipeline was not created with `VK_DYNAMIC_STATE_SAMPLE_LOCATIONS_EXT` enabled.

Otherwise, the sample locations used for rasterization are set by calling `vkCmdSetSampleLocationsEXT`:

    void vkCmdSetSampleLocationsEXT(
        VkCommandBuffer                             commandBuffer,
        const VkSampleLocationsInfoEXT*             pSampleLocationsInfo);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `pSampleLocationsInfo` is the sample locations state to set.

Valid Usage

- The `sampleLocationsPerPixel` member of `pSampleLocationsInfo` must equal the `rasterizationSamples` member of the VkPipelineMultisampleStateCreateInfo structure the bound graphics pipeline has been created with

- If VkPhysicalDeviceSampleLocationsPropertiesEXT::`variableSampleLocations` is `VK_FALSE` then the current render pass must have been begun by specifying a VkRenderPassSampleLocationsBeginInfoEXT structure whose `pPostSubpassSampleLocations` member contains an element with a `subpassIndex` matching the current subpass index and the `sampleLocationsInfo` member of that element must match the sample locations state pointed to by `pSampleLocationsInfo`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pSampleLocationsInfo` must be a valid pointer to a valid VkSampleLocationsInfoEXT structure

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics |

### 26.6. Shading Rate Image

The shading rate image feature allows pipelines to use a shading rate image to control the fragment area and the minimum number of fragment shader invocations launched for each fragment. When the shading rate image is enabled, the rasterizer determines a base shading rate for each region of the framebuffer covered by a primitive by fetching a value from the shading rate image and translating it to a shading rate using a per-viewport shading rate palette. This base shading rate is then adjusted to derive a final shading rate. The final shading rate specifyies the fragment area and fragment shader invocation count to use for fragments generated in the region.

If the `pNext` chain of VkPipelineViewportStateCreateInfo includes a `VkPipelineViewportShadingRateImageStateCreateInfoNV` structure, then that structure includes parameters that control the shading rate.

The `VkPipelineViewportShadingRateImageStateCreateInfoNV` structure is defined as:

    typedef struct VkPipelineViewportShadingRateImageStateCreateInfoNV {
        VkStructureType                  sType;
        const void*                      pNext;
        VkBool32                         shadingRateImageEnable;
        uint32_t                         viewportCount;
        const VkShadingRatePaletteNV*    pShadingRatePalettes;
    } VkPipelineViewportShadingRateImageStateCreateInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `shadingRateImageEnable` specifies whether shading rate image and palettes are used during rasterization.

- `viewportCount` specifies the number of per-viewport palettes used to translate values stored in shading rate images.

- `pShadingRatePalettes` is a pointer to an array of VkShadingRatePaletteNV structures defining the palette for each viewport. If the shading rate palette state is dynamic, this member is ignored.

If this structure is not present, `shadingRateImageEnable` is considered to be `VK_FALSE`, and the shading rate image and palettes are not used.

Valid Usage

- If the multiple viewports feature is not enabled, `viewportCount` must be `0` or `1`

- `viewportCount` must be less than or equal to `VkPhysicalDeviceLimits`::`maxViewports`

- If `shadingRateImageEnable` is `VK_TRUE`, `viewportCount` must be equal to the `viewportCount` member of `VkPipelineViewportStateCreateInfo`

- If no element of the `pDynamicStates` member of `pDynamicState` is `VK_DYNAMIC_STATE_VIEWPORT_SHADING_RATE_PALETTE_NV`, `pShadingRatePalettes` must be a valid pointer to an array of `viewportCount` `VkShadingRatePaletteNV` structures

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_SHADING_RATE_IMAGE_STATE_CREATE_INFO_NV`

- If `viewportCount` is not `0`, and `pShadingRatePalettes` is not `NULL`, `pShadingRatePalettes` must be a valid pointer to an array of `viewportCount` valid VkShadingRatePaletteNV structures

When shading rate image usage is enabled in the bound pipeline, the pipeline uses a shading rate image specified by the command:

    void vkCmdBindShadingRateImageNV(
        VkCommandBuffer                             commandBuffer,
        VkImageView                                 imageView,
        VkImageLayout                               imageLayout);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `imageView` is an image view handle specifying the shading rate image. `imageView` may be set to VK_NULL_HANDLE, which is equivalent to specifying a view of an image filled with zero values.

- `imageLayout` is the layout that the image subresources accessible from `imageView` will be in when the shading rate image is accessed.

Valid Usage

- The shading rate image feature must be enabled.

- If `imageView` is not VK_NULL_HANDLE, it must be a valid VkImageView handle of type `VK_IMAGE_VIEW_TYPE_2D` or `VK_IMAGE_VIEW_TYPE_2D_ARRAY`.

- If `imageView` is not VK_NULL_HANDLE, it must have a format of `VK_FORMAT_R8_UINT`.

- If `imageView` is not VK_NULL_HANDLE, it must have been created with a `usage` value including `VK_IMAGE_USAGE_SHADING_RATE_IMAGE_BIT_NV`

- If `imageView` is not VK_NULL_HANDLE, `imageLayout` must match the actual VkImageLayout of each subresource accessible from `imageView` at the time the subresource is accessed.

- If `imageView` is not VK_NULL_HANDLE, `imageLayout` must be `VK_IMAGE_LAYOUT_SHADING_RATE_OPTIMAL_NV` or `VK_IMAGE_LAYOUT_GENERAL`.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- If `imageView` is not VK_NULL_HANDLE, `imageView` must be a valid VkImageView handle

- `imageLayout` must be a valid VkImageLayout value

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- Both of `commandBuffer`, and `imageView` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics |

When the shading rate image is enabled in the current pipeline, rasterizing a primitive covering the pixel with coordinates (x,y) will fetch a shading rate index value from the shading rate image bound by `vkCmdBindShadingRateImageNV`. If the shading rate image view has a type of `VK_IMAGE_VIEW_TYPE_2D`, the lookup will use texel coordinates (u,v) where \(u = \lfloor \frac{x}{twidth} \rfloor\), \(v = \lfloor \frac{y}{theight} \rfloor\), and \(twidth\) and \(theight\) are the width and height of the implementation-dependent shading rate texel size. If the shading rate image view has a type of `VK_IMAGE_VIEW_TYPE_2D_ARRAY`, the lookup will use texel coordinates (u,v) to extract a texel from the layer l, where l is the layer of the framebuffer being rendered to. If l is greater than or equal to the number of layers in the image view, layer zero will be used.

If the bound shading rate image view is not VK_NULL_HANDLE and contains a texel with coordinates (u,v) in layer l (if applicable), the single unsigned integer component for that texel will be used as the shading rate index. If the (u,v) coordinate is outside the extents of the subresource used by the shading rate image view, or if the image view is VK_NULL_HANDLE, the shading rate index is zero. If the shading rate image view has multiple mipmap levels, the base level identified by `VkImageSubresourceRange`::`baseMipLevel` will be used.

A shading rate index is mapped to a base shading rate using a lookup table called the shading rate image palette. There is a separate palette for each viewport. The number of entries in each palette is given by the implementation-dependent shading rate image palette size.

If a pipeline state object is created with `VK_DYNAMIC_STATE_VIEWPORT_SHADING_RATE_PALETTE_NV` enabled, the per-viewport shading rate image palettes are set by the command:

    void vkCmdSetViewportShadingRatePaletteNV(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    firstViewport,
        uint32_t                                    viewportCount,
        const VkShadingRatePaletteNV*               pShadingRatePalettes);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `firstViewport` is the index of the first viewport whose shading rate palette is updated by the command.

- `viewportCount` is the number of viewports whose shading rate palettes are updated by the command.

- `pShadingRatePalettes` is a pointer to an array of VkShadingRatePaletteNV structures defining the palette for each viewport.

Valid Usage

- The shading rate image feature must be enabled.

- `firstViewport` must be less than `VkPhysicalDeviceLimits`::`maxViewports`

- The sum of `firstViewport` and `viewportCount` must be between `1` and `VkPhysicalDeviceLimits`::`maxViewports`, inclusive

- If the multiple viewports feature is not enabled, `firstViewport` must be `0`

- If the multiple viewports feature is not enabled, `viewportCount` must be `1`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pShadingRatePalettes` must be a valid pointer to an array of `viewportCount` valid VkShadingRatePaletteNV structures

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- `viewportCount` must be greater than `0`

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics |

The `VkShadingRatePaletteNV` structure specifies to contents of a single shading rate image palette and is defined as:

    typedef struct VkShadingRatePaletteNV {
        uint32_t                              shadingRatePaletteEntryCount;
        const VkShadingRatePaletteEntryNV*    pShadingRatePaletteEntries;
    } VkShadingRatePaletteNV;

- `shadingRatePaletteEntryCount` specifies the number of entries in the shading rate image palette.

- `pShadingRatePaletteEntries` is a pointer to an array of VkShadingRatePaletteEntryNV enums defining the shading rate for each palette entry.

Valid Usage

- `shadingRatePaletteEntryCount` must be between `1` and `VkPhysicalDeviceShadingRateImagePropertiesNV`::`shadingRatePaletteSize`, inclusive

Valid Usage (Implicit)

- `pShadingRatePaletteEntries` must be a valid pointer to an array of `shadingRatePaletteEntryCount` valid VkShadingRatePaletteEntryNV values

- `shadingRatePaletteEntryCount` must be greater than `0`

To determine the base shading rate image, a shading rate index i is mapped to array element i in the array `pShadingRatePaletteEntries` for the palette corresponding to the viewport used for the fragment. If i is greater than or equal to the palette size `shadingRatePaletteEntryCount`, the base shading rate is undefined.

The supported shading rate image palette entries are defined by VkShadingRatePaletteEntryNV:

    typedef enum VkShadingRatePaletteEntryNV {
        VK_SHADING_RATE_PALETTE_ENTRY_NO_INVOCATIONS_NV = 0,
        VK_SHADING_RATE_PALETTE_ENTRY_16_INVOCATIONS_PER_PIXEL_NV = 1,
        VK_SHADING_RATE_PALETTE_ENTRY_8_INVOCATIONS_PER_PIXEL_NV = 2,
        VK_SHADING_RATE_PALETTE_ENTRY_4_INVOCATIONS_PER_PIXEL_NV = 3,
        VK_SHADING_RATE_PALETTE_ENTRY_2_INVOCATIONS_PER_PIXEL_NV = 4,
        VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_PIXEL_NV = 5,
        VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_2X1_PIXELS_NV = 6,
        VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_1X2_PIXELS_NV = 7,
        VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_2X2_PIXELS_NV = 8,
        VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_4X2_PIXELS_NV = 9,
        VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_2X4_PIXELS_NV = 10,
        VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_4X4_PIXELS_NV = 11,
        VK_SHADING_RATE_PALETTE_ENTRY_MAX_ENUM_NV = 0x7FFFFFFF
    } VkShadingRatePaletteEntryNV;

The following table indicates the width and height (in pixels) of each fragment generated using the indicated shading rate, as well as the maximum number of fragment shader invocations launched for each fragment. When processing regions of a primitive that have a shading rate of `VK_SHADING_RATE_PALETTE_ENTRY_NO_INVOCATIONS_NV`, no fragments will be generated in that region.

Shading Rate | Width | Height | Invocations
--- | --- | --- | ---
`VK_SHADING_RATE_PALETTE_ENTRY_NO_INVOCATIONS_NV` | 0 | 0 | 0
`VK_SHADING_RATE_PALETTE_ENTRY_16_INVOCATIONS_PER_PIXEL_NV` | 1 | 1 | 16
`VK_SHADING_RATE_PALETTE_ENTRY_8_INVOCATIONS_PER_PIXEL_NV` | 1 | 1 | 8
`VK_SHADING_RATE_PALETTE_ENTRY_4_INVOCATIONS_PER_PIXEL_NV` | 1 | 1 | 4
`VK_SHADING_RATE_PALETTE_ENTRY_2_INVOCATIONS_PER_PIXEL_NV` | 1 | 1 | 2
`VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_PIXEL_NV` | 1 | 1 | 1
`VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_2X1_PIXELS_NV` | 2 | 1 | 1
`VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_1X2_PIXELS_NV` | 1 | 2 | 1
`VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_2X2_PIXELS_NV` | 2 | 2 | 1
`VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_4X2_PIXELS_NV` | 4 | 2 | 1
`VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_2X4_PIXELS_NV` | 2 | 4 | 1
`VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_4X4_PIXELS_NV` | 4 | 4 | 1

When the shading rate image is disabled, a shading rate of `VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_PIXEL_NV` will be used as the base shading rate.

Once a base shading rate has been established, it is adjusted to produce a final shading rate. First, if the base shading rate uses multiple pixels for each fragment, the implementation may reduce the fragment area to ensure that the total number of coverage samples for all pixels in a fragment does not exceed an implementation-dependent maximum.

If sample shading is active in the current pipeline and would result in processing n (n > 1) unique samples per fragment when the shading rate image is disabled, the shading rate is adjusted in an implementation-dependent manner to increase the number of fragment shader invocations spawned by the primitive. If the shading rate indicates fs pixels per fragment and fs is greater than n, the fragment area is adjusted so each fragment has approximately \(fs \over n\) pixels. Otherwise, if the shading rate indicates ipf invocations per fragment, the fragment area will be adjusted to a single pixel with approximately \(ipf \times n \over fs\) invocations per fragment.

If sample shading occurs due to the use of a fragment shader input variable decorated with `SampleId` or `SamplePosition`, the shading rate is ignored. Each fragment will have a single pixel and will spawn up to `totalSamples` fragment shader invocations, as when using sample shading without a shading rate image.

Finally, if the shading rate specifies multiple fragment shader invocations per fragment, the total number of invocations in the shading rate is clamped to be no larger than the value of `totalSamples` used for sample shading.

When the final shading rate for a primitive covering pixel (x,y) has a fragment area of \(fw \times fh\), the fragment for that pixel will cover all pixels with coordinates (x',y') that satisfy the equations:

\[\begin{aligned} \lfloor \frac{x}{fw} \rfloor == \lfloor \frac{x'}{fw} \rfloor \end{aligned}\]
\[\begin{aligned} \lfloor \frac{y}{fh} \rfloor == \lfloor \frac{y'}{fh} \rfloor \end{aligned}\]

This combined fragment is considered to have multiple coverage samples; the total number of samples in this fragment is given by \(samples = fw \times fh \times rs\) where rs indicates the value of `VkPipelineMultisampleStateCreateInfo`::`rasterizationSamples` specified at pipeline creation time. The set of coverage samples in the fragment is the union of the per-pixel coverage samples in each of the fragment’s pixels The location and order of coverage samples within each pixel in the combined fragment are assigned as described in Multisampling and Custom Sample Locations. Each coverage sample in the set of pixels belonging to the combined fragment is assigned a unique sample number in the range [0,samples-1]. If the shadingRateCoarseSampleOrder feature is supported, the order of coverage samples can be specified for each combination of fragment area and coverage sample count. If this feature is not supported, the sample order is implementation-dependent.

If the `pNext` chain of VkPipelineViewportStateCreateInfo includes a `VkPipelineViewportCoarseSampleOrderStateCreateInfoNV` structure, then that structure includes parameters that control the order of coverage samples in fragments larger than one pixel.

The `VkPipelineViewportCoarseSampleOrderStateCreateInfoNV` structure is defined as:

    typedef struct VkPipelineViewportCoarseSampleOrderStateCreateInfoNV {
        VkStructureType                       sType;
        const void*                           pNext;
        VkCoarseSampleOrderTypeNV             sampleOrderType;
        uint32_t                              customSampleOrderCount;
        const VkCoarseSampleOrderCustomNV*    pCustomSampleOrders;
    } VkPipelineViewportCoarseSampleOrderStateCreateInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `sampleOrderType` specifies the mechanism used to order coverage samples in fragments larger than one pixel.

- `customSampleOrderCount` specifies the number of custom sample orderings to use when ordering coverage samples.

- `pCustomSampleOrders` is a pointer to an array of `customSampleOrderCount` VkCoarseSampleOrderCustomNV structures, each of which specifies the coverage sample order for a single combination of fragment area and coverage sample count.

If this structure is not present, `sampleOrderType` is considered to be `VK_COARSE_SAMPLE_ORDER_TYPE_DEFAULT_NV`.

If `sampleOrderType` is `VK_COARSE_SAMPLE_ORDER_TYPE_CUSTOM_NV`, the coverage sample order used for any combination of fragment area and coverage sample count not enumerated in `pCustomSampleOrders` will be identical to that used for `VK_COARSE_SAMPLE_ORDER_TYPE_DEFAULT_NV`.

If the pipeline was created with `VK_DYNAMIC_STATE_VIEWPORT_COARSE_SAMPLE_ORDER_NV`, the contents of this structure (if present) are ignored, and the coverage sample order is instead specified by vkCmdSetCoarseSampleOrderNV.

Valid Usage

- If `sampleOrderType` is not `VK_COARSE_SAMPLE_ORDER_TYPE_CUSTOM_NV`, `customSamplerOrderCount` must be `0`

- The array `pCustomSampleOrders` must not contain two structures with matching values for both the `shadingRate` and `sampleCount` members.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_COARSE_SAMPLE_ORDER_STATE_CREATE_INFO_NV`

- `sampleOrderType` must be a valid VkCoarseSampleOrderTypeNV value

- If `customSampleOrderCount` is not `0`, `pCustomSampleOrders` must be a valid pointer to an array of `customSampleOrderCount` valid VkCoarseSampleOrderCustomNV structures

The type VkCoarseSampleOrderTypeNV specifies the technique used to order coverage samples in fragments larger than one pixel, and is defined as:

    typedef enum VkCoarseSampleOrderTypeNV {
        VK_COARSE_SAMPLE_ORDER_TYPE_DEFAULT_NV = 0,
        VK_COARSE_SAMPLE_ORDER_TYPE_CUSTOM_NV = 1,
        VK_COARSE_SAMPLE_ORDER_TYPE_PIXEL_MAJOR_NV = 2,
        VK_COARSE_SAMPLE_ORDER_TYPE_SAMPLE_MAJOR_NV = 3,
        VK_COARSE_SAMPLE_ORDER_TYPE_MAX_ENUM_NV = 0x7FFFFFFF
    } VkCoarseSampleOrderTypeNV;

- `VK_COARSE_SAMPLE_ORDER_TYPE_DEFAULT_NV` specifies that coverage samples will be ordered in an implementation-dependent manner.

- `VK_COARSE_SAMPLE_ORDER_TYPE_CUSTOM_NV` specifies that coverage samples will be ordered according to the array of custom orderings provided in either the `pCustomSampleOrders` member of `VkPipelineViewportCoarseSampleOrderStateCreateInfoNV` or the `pCustomSampleOrders` member of vkCmdSetCoarseSampleOrderNV.

- `VK_COARSE_SAMPLE_ORDER_TYPE_PIXEL_MAJOR_NV` specifies that coverage samples will be ordered sequentially, sorted first by pixel coordinate (in row-major order) and then by coverage sample number.

- `VK_COARSE_SAMPLE_ORDER_TYPE_SAMPLE_MAJOR_NV` specifies that coverage samples will be ordered sequentially, sorted first by coverage sample number and then by pixel coordinate (in row-major order).

When using a coarse sample order of `VK_COARSE_SAMPLE_ORDER_TYPE_PIXEL_MAJOR_NV` for a fragment with an upper-left corner of \((fx,fy)\) with a width of \(fw \times fh\) and \(fsc\) coverage samples per pixel, sample \(cs\) of the fragment will be assigned to sample \(fs\) of pixel \((px,py)\) will be assigned as follows:

\[\begin{aligned} px = & fx + (\lfloor {cs \over fsc} \rfloor \text{ \% } fw) \\ py = & fy + \lfloor {cs \over {fsc \times fw}} \rfloor \\ fs = & cs \text{ \% } fsc \end{aligned}\]

When using a coarse sample order of `VK_COARSE_SAMPLE_ORDER_TYPE_SAMPLE_MAJOR_NV`, sample \(cs\) will be assigned as follows:

\[\begin{aligned} px = & fx + cs \text{ \% } fw \\ py = & (fy + \lfloor {cs \over fw} \rfloor \text{ \% } fh) \\ fs = & \lfloor {cs \over {fw \times fh}} \rfloor \end{aligned}\]

The `VkCoarseSampleOrderCustomNV` structure is used with a coverage sample ordering type of `VK_COARSE_SAMPLE_ORDER_TYPE_CUSTOM_NV` to specify the order of coverage samples for one combination of fragment width, fragment height, and coverage sample count. The structure is defined as:

    typedef struct VkCoarseSampleOrderCustomNV {
        VkShadingRatePaletteEntryNV        shadingRate;
        uint32_t                           sampleCount;
        uint32_t                           sampleLocationCount;
        const VkCoarseSampleLocationNV*    pSampleLocations;
    } VkCoarseSampleOrderCustomNV;

- `shadingRate` is a shading rate palette entry that identifies the fragment width and height for the combination of fragment area and per-pixel coverage sample count to control.

- `sampleCount` identifies the per-pixel coverage sample count for the combination of fragment area and coverage sample count to control.

- `sampleLocationCount` specifies the number of sample locations in the custom ordering.

- `pSampleLocations` is a pointer to an array of VkCoarseSampleOrderCustomNV structures specifying the location of each sample in the custom ordering.

When using a custom sample ordering, element i in `pSampleLocations` specifies a specific pixel and per-pixel coverage sample number that corresponds to the coverage sample numbered i in the multi-pixel fragment.

Valid Usage

- `shadingRate` must be a shading rate that generates fragments with more than one pixel.

- `sampleCount` must correspond to a sample count enumerated in VkSampleCountFlags whose corresponding bit is set in VkPhysicalDeviceLimits::`framebufferNoAttachmentsSampleCounts`.

- `sampleLocationCount` must be equal to the product of `sampleCount`, the fragment width for `shadingRate`, and the fragment height for `shadingRate`.

- `sampleLocationCount` must be less than or equal to the value of `VkPhysicalDeviceShadingRateImagePropertiesNV`::`shadingRateMaxCoarseSamples`.

- The array `pSampleLocations` must contain exactly one entry for every combination of valid values for `pixelX`, `pixelY`, and `sample` in the structure VkCoarseSampleOrderCustomNV.

Valid Usage (Implicit)

- `shadingRate` must be a valid VkShadingRatePaletteEntryNV value

- `pSampleLocations` must be a valid pointer to an array of `sampleLocationCount` VkCoarseSampleLocationNV structures

- `sampleLocationCount` must be greater than `0`

The `VkCoarseSampleLocationNV` structure identifies a specific pixel and sample number for one of the coverage samples in a fragment that is larger than one pixel. This structure is defined as:

    typedef struct VkCoarseSampleLocationNV {
        uint32_t    pixelX;
        uint32_t    pixelY;
        uint32_t    sample;
    } VkCoarseSampleLocationNV;

- `pixelX` is added to the x coordinate of the upper-leftmost pixel of each fragment to identify the pixel containing the coverage sample.

- `pixelY` is added to the y coordinate of the upper-leftmost pixel of each fragment to identify the pixel containing the coverage sample.

- `sample` is the number of the coverage sample in the pixel identified by `pixelX` and `pixelY`.

Valid Usage

- `pixelX` must be less than the width (in pixels) of the fragment.

- `pixelY` must be less than the height (in pixels) of the fragment.

- `sample` must be less than the number of coverage samples in each pixel belonging to the fragment.

If a pipeline state object is created with `VK_DYNAMIC_STATE_VIEWPORT_COARSE_SAMPLE_ORDER_NV` enabled, the order of coverage samples in fragments larger than one pixel is set by the command:

    void vkCmdSetCoarseSampleOrderNV(
        VkCommandBuffer                             commandBuffer,
        VkCoarseSampleOrderTypeNV                   sampleOrderType,
        uint32_t                                    customSampleOrderCount,
        const VkCoarseSampleOrderCustomNV*          pCustomSampleOrders);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `sampleOrderType` specifies the mechanism used to order coverage samples in fragments larger than one pixel.

- `customSampleOrderCount` specifies the number of custom sample orderings to use when ordering coverage samples.

- `pCustomSampleOrders` is a pointer to an array of VkCoarseSampleOrderCustomNV structures, each of which specifies the coverage sample order for a single combination of fragment area and coverage sample count.

If `sampleOrderType` is `VK_COARSE_SAMPLE_ORDER_TYPE_CUSTOM_NV`, the coverage sample order used for any combination of fragment area and coverage sample count not enumerated in `pCustomSampleOrders` will be identical to that used for `VK_COARSE_SAMPLE_ORDER_TYPE_DEFAULT_NV`.

Valid Usage

- If `sampleOrderType` is not `VK_COARSE_SAMPLE_ORDER_TYPE_CUSTOM_NV`, `customSamplerOrderCount` must be `0`

- The array `pCustomSampleOrders` must not contain two structures with matching values for both the `shadingRate` and `sampleCount` members.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `sampleOrderType` must be a valid VkCoarseSampleOrderTypeNV value

- If `customSampleOrderCount` is not `0`, `pCustomSampleOrders` must be a valid pointer to an array of `customSampleOrderCount` valid VkCoarseSampleOrderCustomNV structures

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics |

If the final shading rate for a primitive covering pixel (x,y) results in n invocations per pixel (n > 1), n separate fragment shader invocations will be generated for the fragment. Each coverage sample in the fragment will be assigned to one of the n fragment shader invocations in an implementation-dependent manner. The outputs from the fragment output interface of each shader invocation will be broadcast to all of the framebuffer samples associated with the invocation. If none of the coverage samples associated with a fragment shader invocation is covered by a primitive, the implementation may discard the fragment shader invocation for those samples.

If the final shading rate for a primitive covering pixel (x,y) results in a fragment containing multiple pixels, a single set of fragment shader invocations will be generated for all pixels in the combined fragment. Outputs from the fragment output interface will be broadcast to all covered framebuffer samples belonging to the fragment. If the fragment shader executes code discarding the fragment, none of the samples of the fragment will be updated.

### 26.7. Sample Shading

Sample shading can be used to specify a minimum number of unique samples to process for each fragment. If sample shading is enabled an implementation must provide a minimum of max(⌈ `minSampleShadingFactor` × `totalSamples` ⌉, 1) unique associated data for each fragment, where `minSampleShadingFactor` is the minimum fraction of sample shading. If the `VK_AMD_mixed_attachment_samples` extension is enabled and the subpass uses color attachments, `totalSamples` is the number of samples of the color attachments. Otherwise, `totalSamples` is the value of VkPipelineMultisampleStateCreateInfo::`rasterizationSamples` specified at pipeline creation time. These are associated with the samples in an implementation-dependent manner. When `minSampleShadingFactor` is `1.0`, a separate set of associated data are evaluated for each sample, and each set of values is evaluated at the sample location.

Sample shading is enabled for a graphics pipeline:

- If the interface of the fragment shader entry point of the graphics pipeline includes an input variable decorated with `SampleId` or `SamplePosition`. In this case `minSampleShadingFactor` takes the value `1.0`.

- Else if the `sampleShadingEnable` member of the VkPipelineMultisampleStateCreateInfo structure specified when creating the graphics pipeline is set to `VK_TRUE`. In this case `minSampleShadingFactor` takes the value of VkPipelineMultisampleStateCreateInfo::`minSampleShading`.

Otherwise, sample shading is considered disabled.

### 26.8. Barycentric Interpolation

When the `fragmentShaderBarycentric` feature is enabled, the `PerVertexNV` interpolation decoration can be used with fragment shader inputs to indicate that the decorated inputs do not have associated data in the fragment. Such inputs can only be accessed in a fragment shader using an array index whose value (0, 1, or 2) identifies one of the vertices of the primitive that produced the fragment.

When tessellation, geometry shading, and mesh shading are not active, fragment shader inputs decorated with `PerVertexNV` will take values from one of the vertices of the primitive that produced the fragment, identified by the extra index provided in SPIR-V code accessing the input. If the n vertices passed to a draw call are numbered 0 through n-1, and the point, line, and triangle primitives produced by the draw call are numbered with consecutive integers beginning with zero, the following table indicates the original vertex numbers used for index values of 0, 1, and 2. If an input decorated with `PerVertexNV` is accessed with any other vertex index value, the value obtained is undefined.

Primitive Topology | Vertex 0 | Vertex 1 | Vertex 2
--- | --- | --- | ---
`VK_PRIMITIVE_TOPOLOGY_POINT_LIST` | i | - | -
`VK_PRIMITIVE_TOPOLOGY_LINE_LIST` | 2i | 2i+1 | -
`VK_PRIMITIVE_TOPOLOGY_LINE_STRIP` | i | i+1 | -
`VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST` | 3i | 3i+1 | 3i+2
`VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP` (even) | i | i+1 | i+2
`VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP` (odd) | i | i+2 | i+1
`VK_PRIMITIVE_TOPOLOGY_TRIANGLE_FAN` | i+1 | i+2 | 0
`VK_PRIMITIVE_TOPOLOGY_LINE_LIST_WITH_ADJACENCY` | 4i+1 | 4i+2 | -
`VK_PRIMITIVE_TOPOLOGY_LINE_STRIP_WITH_ADJACENCY` | i+1 | i+2 | -
`VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST_WITH_ADJACENCY` | 6i | 6i+2 | 6i+4
`VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP_WITH_ADJACENCY` (even) | 2i | 2i+2 | 2i+4
`VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP_WITH_ADJACENCY` (odd) | 2i | 2i+4 | 2i+2

When geometry or mesh shading is active, primitives processed by fragment shaders are assembled from the vertices emitted by the geometry or mesh shader. In this case, the vertices used for fragment shader inputs decorated with `PerVertexNV` are derived by treating the primitives produced by the shader as though they were specified by a draw call and consulting the table above.

When using tessellation without geometry shading, the tessellator produces primitives in an implementation-dependent manner. While there is no defined vertex ordering for inputs decorated with `PerVertexNV`, the vertex ordering used in this case will be consistent with the ordering used to derive the values of inputs decorated with `BaryCoordNV` or `BaryCoordNoPerspNV`.

Fragment shader inputs decorated with `BaryCoordNV` or `BaryCoordNoPerspNV` hold three-component vectors with barycentric weights that indicate the location of the fragment relative to the screen-space locations of vertices of its primitive. For point primitives, such variables are always assigned the value (1,0,0). For line primitives, the built-ins are obtained by interpolating an attribute whose values for the vertices numbered 0 and 1 are (1,0,0) and (0,1,0), respectively. For polygon primitives, the built-ins are obtained by interpolating an attribute whose values for the vertices numbered 0, 1, and 2 are (1,0,0), (0,1,0), and (0,0,1), respectively. For `BaryCoordNV`, the values are obtained using perspective interpolation. For `BaryCoordNoPerspNV`, the values are obtained using linear interpolation.

### 26.9. Points

A point is drawn by generating a set of fragments in the shape of a square centered around the vertex of the point. Each vertex has an associated point size that controls the width/height of that square. The point size is taken from the (potentially clipped) shader built-in `PointSize` written by:

- the geometry shader, if active;

- the tessellation evaluation shader, if active and no geometry shader is active;

- the vertex shader, otherwise

and clamped to the implementation-dependent point size range [`pointSizeRange`[0],`pointSizeRange`[1]]. The value written to `PointSize` must be greater than zero.

Not all point sizes need be supported, but the size 1.0 must be supported. The range of supported sizes and the size of evenly-spaced gradations within that range are implementation-dependent. The range and gradations are obtained from the `pointSizeRange` and `pointSizeGranularity` members of VkPhysicalDeviceLimits. If, for instance, the size range is from 0.1 to 2.0 and the gradation size is 0.1, then the size 0.1, 0.2, …​, 1.9, 2.0 are supported. Additional point sizes may also be supported. There is no requirement that these sizes be equally spaced. If an unsupported size is requested, the nearest supported size is used instead.

Further, if the render pass has a fragment density map attachment, point size may be rounded by the implementation to a multiple of the fragment’s width or height.

#### 26.9.1. Basic Point Rasterization

Point rasterization produces a fragment for each fragment area group of framebuffer pixels with one or more sample points that intersect a region centered at the point’s (xf,yf). This region is a square with side equal to the current point size. Coverage bits that correspond to sample points that intersect the region are 1, other coverage bits are 0. All fragments produced in rasterizing a point are assigned the same associated data, which are those of the vertex corresponding to the point. However, the fragment shader built-in `PointCoord` contains point sprite texture coordinates. The s and t point sprite texture coordinates vary from zero to one across the point horizontally left-to-right and top-to-bottom, respectively. The following formulas are used to evaluate s and t:

\[s = {1 \over 2} + { \left( x_p - x_f \right) \over \text{size} }\]
\[t = {1 \over 2} + { \left( y_p - y_f \right) \over \text{size} }\]

where size is the point’s size; (xp,yp) is the location at which the point sprite coordinates are evaluated - this may be the framebuffer coordinates of the fragment center, or the location of a sample; and (xf,yf) is the exact, unrounded framebuffer coordinate of the vertex for the point.

### 26.10. Line Segments

Line segment rasterization options are controlled by the VkPipelineRasterizationLineStateCreateInfoEXT structure.

The `VkPipelineRasterizationLineStateCreateInfoEXT` structure is defined as:

    typedef struct VkPipelineRasterizationLineStateCreateInfoEXT {
        VkStructureType               sType;
        const void*                   pNext;
        VkLineRasterizationModeEXT    lineRasterizationMode;
        VkBool32                      stippledLineEnable;
        uint32_t                      lineStippleFactor;
        uint16_t                      lineStipplePattern;
    } VkPipelineRasterizationLineStateCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `lineRasterizationMode` is a VkLineRasterizationModeEXT value selecting the style of line rasterization.

- `stippledLineEnable` enables stippled line rasterization.

- `lineStippleFactor` is the repeat factor used in stippled line rasterization.

- `lineStipplePattern` is the bit pattern used in stippled line rasterization.

Valid Usage

- If `lineRasterizationMode` is `VK_LINE_RASTERIZATION_MODE_RECTANGULAR_EXT`, then the rectangularLines feature must be enabled

- If `lineRasterizationMode` is `VK_LINE_RASTERIZATION_MODE_BRESENHAM_EXT`, then the bresenhamLines feature must be enabled

- If `lineRasterizationMode` is `VK_LINE_RASTERIZATION_MODE_RECTANGULAR_SMOOTH_EXT`, then the smoothLines feature must be enabled

- If `stippledLineEnable` is `VK_TRUE` and `lineRasterizationMode` is `VK_LINE_RASTERIZATION_MODE_RECTANGULAR_EXT`, then the stippledRectangularLines feature must be enabled

- If `stippledLineEnable` is `VK_TRUE` and `lineRasterizationMode` is `VK_LINE_RASTERIZATION_MODE_BRESENHAM_EXT`, then the stippledBresenhamLines feature must be enabled

- If `stippledLineEnable` is `VK_TRUE` and `lineRasterizationMode` is `VK_LINE_RASTERIZATION_MODE_RECTANGULAR_SMOOTH_EXT`, then the stippledSmoothLines feature must be enabled

- If `stippledLineEnable` is `VK_TRUE` and `lineRasterizationMode` is `VK_LINE_RASTERIZATION_MODE_DEFAULT_EXT`, then the stippledRectangularLines feature must be enabled and VkPhysicalDeviceLimits::`strictLines` must be `VK_TRUE`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_LINE_STATE_CREATE_INFO_EXT`

- `lineRasterizationMode` must be a valid VkLineRasterizationModeEXT value

Possible values of VkPipelineRasterizationLineStateCreateInfoEXT::`lineRasterizationMode` are:

    typedef enum VkLineRasterizationModeEXT {
        VK_LINE_RASTERIZATION_MODE_DEFAULT_EXT = 0,
        VK_LINE_RASTERIZATION_MODE_RECTANGULAR_EXT = 1,
        VK_LINE_RASTERIZATION_MODE_BRESENHAM_EXT = 2,
        VK_LINE_RASTERIZATION_MODE_RECTANGULAR_SMOOTH_EXT = 3,
        VK_LINE_RASTERIZATION_MODE_MAX_ENUM_EXT = 0x7FFFFFFF
    } VkLineRasterizationModeEXT;

- `VK_LINE_RASTERIZATION_MODE_DEFAULT_EXT` is equivalent to `VK_LINE_RASTERIZATION_MODE_RECTANGULAR_EXT` if VkPhysicalDeviceLimits::`strictLines` is `VK_TRUE`, otherwise lines are drawn as non-`strictLines` parallelograms. Both of these modes are defined in Basic Line Segment Rasterization.

- `VK_LINE_RASTERIZATION_MODE_RECTANGULAR_EXT` specifies lines drawn as if they were rectangles extruded from the line

- `VK_LINE_RASTERIZATION_MODE_BRESENHAM_EXT` specifies lines drawn by determining which pixel diamonds the line intersects and exits, as defined in Bresenham Line Segment Rasterization.

- `VK_LINE_RASTERIZATION_MODE_RECTANGULAR_SMOOTH_EXT` specifies lines drawn if they were rectangles extruded from the line, with alpha falloff, as defined in Smooth Lines.

Each line segment has an associated width. The line width is specified by the VkPipelineRasterizationStateCreateInfo::`lineWidth` property of the currently active pipeline, if the pipeline was not created with `VK_DYNAMIC_STATE_LINE_WIDTH` enabled.

Otherwise, the line width is set by calling `vkCmdSetLineWidth`:

    void vkCmdSetLineWidth(
        VkCommandBuffer                             commandBuffer,
        float                                       lineWidth);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `lineWidth` is the width of rasterized line segments.

Valid Usage

- If the wide lines feature is not enabled, `lineWidth` must be `1.0`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics |

Not all line widths need be supported for line segment rasterization, but width 1.0 antialiased segments must be provided. The range and gradations are obtained from the `lineWidthRange` and `lineWidthGranularity` members of VkPhysicalDeviceLimits. If, for instance, the size range is from 0.1 to 2.0 and the gradation size is 0.1, then the size 0.1, 0.2, …​, 1.9, 2.0 are supported. Additional line widths may also be supported. There is no requirement that these widths be equally spaced. If an unsupported width is requested, the nearest supported width is used instead.

Further, if the render pass has a fragment density map attachment, line width may be rounded by the implementation to a multiple of the fragment’s width or height.

#### 26.10.1. Basic Line Segment Rasterization

If the `lineRasterizationMode` member of VkPipelineRasterizationLineStateCreateInfoEXT is `VK_LINE_RASTERIZATION_MODE_RECTANGULAR_EXT`, rasterized line segments produce fragments which intersect a rectangle centered on the line segment. Two of the edges are parallel to the specified line segment; each is at a distance of one-half the current width from that segment in directions perpendicular to the direction of the line. The other two edges pass through the line endpoints and are perpendicular to the direction of the specified line segment. Coverage bits that correspond to sample points that intersect the rectangle are 1, other coverage bits are 0.

Next we specify how the data associated with each rasterized fragment are obtained. Let pr = (xd, yd) be the framebuffer coordinates at which associated data are evaluated. This may be the center of a fragment or the location of a sample within the fragment. When `rasterizationSamples` is `VK_SAMPLE_COUNT_1_BIT`, the fragment center must be used. Let pa = (xa, ya) and pb = (xb,yb) be initial and final endpoints of the line segment, respectively. Set

\[t = {{( \mathbf{p}_r - \mathbf{p}_a ) \cdot ( \mathbf{p}_b - \mathbf{p}_a )} \over {\| \mathbf{p}_b - \mathbf{p}_a \|^2 }}\]

(Note that t = 0 at pa and t = 1 at pb. Also note that this calculation projects the vector from pa to pr onto the line, and thus computes the normalized distance of the fragment along the line.)

The value of an associated datum f for the fragment, whether it be a shader output or the clip w coordinate, must be determined using perspective interpolation:

\[f = {{ (1-t) {f_a / w_a} + t { f_b / w_b} } \over {(1-t) / w_a + t / w_b }}\]

where fa and fb are the data associated with the starting and ending endpoints of the segment, respectively; wa and wb are the clip w coordinates of the starting and ending endpoints of the segments, respectively.

Depth values for lines must be determined using linear interpolation:

  z = (1 - t) za + t zb

where za and zb are the depth values of the starting and ending endpoints of the segment, respectively.

The `NoPerspective` and `Flat` interpolation decorations can be used with fragment shader inputs to declare how they are interpolated. When neither decoration is applied, perspective interpolation is performed as described above. When the `NoPerspective` decoration is used, linear interpolation is performed in the same fashion as for depth values, as described above. When the `Flat` decoration is used, no interpolation is performed, and outputs are taken from the corresponding input value of the provoking vertex corresponding to that primitive.

When the `fragmentShaderBarycentric` feature is enabled, the `PerVertexNV` interpolation decoration can also be used with fragment shader inputs which indicate that the decorated inputs are not interpolated and can only be accessed using an extra array dimension, where the extra index identifies one of the vertices of the primitive that produced the fragment.

The above description documents the preferred method of line rasterization, and must be used when the implementation advertises the `strictLines` limit in VkPhysicalDeviceLimits as `VK_TRUE`.

When `strictLines` is `VK_FALSE`, the edges of the lines are generated as a parallelogram surrounding the original line. The major axis is chosen by noting the axis in which there is the greatest distance between the line start and end points. If the difference is equal in both directions then the X axis is chosen as the major axis. Edges 2 and 3 are aligned to the minor axis and are centered on the endpoints of the line as in Non strict lines, and each is `lineWidth` long. Edges 0 and 1 are parallel to the line and connect the endpoints of edges 2 and 3. Coverage bits that correspond to sample points that intersect the parallelogram are 1, other coverage bits are 0.

Samples that fall exactly on the edge of the parallelogram follow the polygon rasterization rules.

Interpolation occurs as if the parallelogram was decomposed into two triangles where each pair of vertices at each end of the line has identical attributes.

Figure 17. Non strict lines

#### 26.10.2. Bresenham Line Segment Rasterization

If `lineRasterizationMode` is `VK_LINE_RASTERIZATION_MODE_BRESENHAM_EXT`, then the following rules replace the line rasterization rules defined in Basic Line Segment Rasterization.

Line segment rasterization begins by characterizing the segment as either x-major or y-major. x-major line segments have slope in the closed interval [-1,1]; all other line segments are y-major (slope is determined by the segment’s endpoints). We specify rasterization only for x-major segments except in cases where the modifications for y-major segments are not self-evident.

Ideally, Vulkan uses a diamond-exit rule to determine those fragments that are produced by rasterizing a line segment. For each fragment f with center at framebuffer coordinates xf and yf, define a diamond-shaped region that is the intersection of four half planes:

\[ R_f = \{ (x,y) \mid | x - x_f | + | y - y_f | < \frac{1}{2} \}\]

Essentially, a line segment starting at pa and ending at pb produces those fragments f for which the segment intersects Rf, except if pb is contained in Rf.

Figure 18. Visualization of Bresenham’s algorithm

To avoid difficulties when an endpoint lies on a boundary of Rf we (in principle) perturb the supplied endpoints by a tiny amount. Let pa and pb have framebuffer coordinates (xa, ya) and (xb, yb), respectively. Obtain the perturbed endpoints pa' given by (xa, ya) - (ε, ε2) and pb' given by (xb, yb) - (ε, ε2). Rasterizing the line segment starting at pa and ending at pb produces those fragments f for which the segment starting at pa' and ending on pb' intersects Rf, except if pb' is contained in Rf. ε is chosen to be so small that rasterizing the line segment produces the same fragments when δ is substituted for ε for any 0 < δ ≤ ε.

When pa and pb lie on fragment centers, this characterization of fragments reduces to Bresenham’s algorithm with one modification: lines produced in this description are "half-open," meaning that the final fragment (corresponding to pb) is not drawn. This means that when rasterizing a series of connected line segments, shared endpoints will be produced only once rather than twice (as would occur with Bresenham’s algorithm).

Implementations may use other line segment rasterization algorithms, subject to the following rules:

- The coordinates of a fragment produced by the algorithm must not deviate by more than one unit in either x or y framebuffer coordinates from a corresponding fragment produced by the diamond-exit rule.

- The total number of fragments produced by the algorithm must not differ from that produced by the diamond-exit rule by no more than one.

- For an x-major line, two fragments that lie in the same framebuffer-coordinate column must not be produced (for a y-major line, two fragments that lie in the same framebuffer-coordinate row must not be produced).

- If two line segments share a common endpoint, and both segments are either x-major (both left-to-right or both right-to-left) or y-major (both bottom-to-top or both top-to-bottom), then rasterizing both segments must not produce duplicate fragments. Fragments also must not be omitted so as to interrupt continuity of the connected segments.

The actual width w of `VK_LINE_RASTERIZATION_MODE_BRESENHAM_EXT` lines is determined by rounding the line width to the nearest integer, clamping it to the implementation-dependent `lineWidthRange` (with both values rounded to the nearest integer), then clamping it to be no less than 1.

`VK_LINE_RASTERIZATION_MODE_BRESENHAM_EXT` line segments of width other than one are rasterized by offsetting them in the minor direction (for an x-major line, the minor direction is y, and for a y-major line, the minor direction is x) and producing a row or column of fragments in the minor direction. If the line segment has endpoints given by (x0, y0) and (x1, y1) in framebuffer coordinates, the segment with endpoints \((x_0, y_0 - \frac{w-1}{2})\) and \((x_1, y_1 - \frac{w-1}{2})\) is rasterized, but instead of a single fragment, a column of fragments of height w (a row of fragments of length w for a y-major segment) is produced at each x (y for y-major) location. The lowest fragment of this column is the fragment that would be produced by rasterizing the segment of width 1 with the modified coordinates.

The preferred method of attribute interpolation for a wide line is to generate the same attribute values for all fragments in the row or column described above, as if the adjusted line were used for interpolation and those values replicated to the other fragments, except for `FragCoord` which is interpolated as usual. Implementations may instead interpolate each fragment according to the formula in Basic Line Segment Rasterization, using the original line segment endpoints.

When `VK_LINE_RASTERIZATION_MODE_BRESENHAM_EXT` lines are being rasterized, sample locations may all be treated as being at the pixel center (this may affect attribute and depth interpolation).

| Note The sample locations described above are not used for determining coverage, they are only used for things like attribute interpolation. The rasterization rules that determine coverage are defined in terms of whether the line intersects pixels, as opposed to the point sampling rules used for other primitive types. So these rules are independent of the sample locations. One consequence of this is that Bresenham lines cover the same pixels regardless of the number of rasterization samples, and cover all samples in those pixels (unless masked out or killed).

#### 26.10.3. Line Stipple

If the `stippledLineEnable` member of VkPipelineRasterizationLineStateCreateInfoEXT is `VK_TRUE`, then lines are rasterized with a line stipple determined by `lineStippleFactor` and `lineStipplePattern`. `lineStipplePattern` is an unsigned 16-bit integer that determines which fragments are to be drawn or discarded when the line is rasterized. `lineStippleFactor` is a count that is used to modify the effective line stipple by causing each bit in `lineStipplePattern` to be used `lineStippleFactor` times.

Line stippling discards certain fragments that are produced by rasterization. The masking is achieved using three parameters: the 16-bit line stipple pattern p, the line stipple factor r, and an integer stipple counter s. Let

\[ b = \lfloor \frac{s}{r} \rfloor \bmod 16\]

Then a fragment is produced if the b’th bit of p is 1, and discarded otherwise. The bits of p are numbered with 0 being the least significant and 15 being the most significant.

The initial value of s is zero. For `VK_LINE_RASTERIZATION_MODE_BRESENHAM_EXT` lines, s is incremented after production of each fragment of a line segment (fragments are produced in order, beginning at the starting point and working towards the ending point). For `VK_LINE_RASTERIZATION_MODE_RECTANGULAR_EXT` and `VK_LINE_RASTERIZATION_MODE_RECTANGULAR_SMOOTH_EXT` lines, the rectangular region is subdivided into adjacent unit-length rectangles, and s is incremented once for each rectangle. Rectangles with a value of s such that the b’th bit of p is zero are discarded. If the last rectangle in a line segment is shorter than unit-length, then the remainder may carry over to the next line segment in the line strip using the same value of s (this is the preferred behavior, for the stipple pattern to appear more consistent through the strip).

s is reset to 0 at the start of each strip (for line strips), and before every line segment in a group of independent segments.

If the line segment has been clipped, then the value of s at the beginning of the line segment is implementation-dependent.

The line stipple factor and pattern are specified by the VkPipelineRasterizationLineStateCreateInfoEXT::`lineStippleFactor` and VkPipelineRasterizationLineStateCreateInfoEXT::`lineStipplePattern` members of the currently active pipeline, if the pipeline was not created with `VK_DYNAMIC_STATE_LINE_STIPPLE_EXT` enabled.

Otherwise, the line stipple factor and pattern are set by calling `vkCmdSetLineStippleEXT`:

    void vkCmdSetLineStippleEXT(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    lineStippleFactor,
        uint16_t                                    lineStipplePattern);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `lineStippleFactor` is the repeat factor used in stippled line rasterization.

- `lineStipplePattern` is the bit pattern used in stippled line rasterization.

Valid Usage

- `lineStippleFactor` must be in the range [1,256]

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics |

#### 26.10.4. Smooth Lines

If the `lineRasterizationMode` member of VkPipelineRasterizationLineStateCreateInfoEXT is `VK_LINE_RASTERIZATION_MODE_RECTANGULAR_SMOOTH_EXT`, then lines are considered to be rectangles using the same geometry as for `VK_LINE_RASTERIZATION_MODE_RECTANGULAR_EXT` lines. The rules for determining which pixels are covered are implementation-dependent, and may include nearby pixels where no sample locations are covered or where the rectangle doesn’t intersect the pixel at all. For each pixel that is considered covered, the fragment computes a coverage value that approximates the area of the intersection of the rectangle with the pixel square, and this coverage value is multiplied into the color location 0’s alpha value after fragment shading, as described in Multisample Coverage.

| Note The details of the rasterization rules and area calculation are left intentionally vague, to allow implementations to generate coverage and values that are aesthetically pleasing.

### 26.11. Polygons

A polygon results from the decomposition of a triangle strip, triangle fan or a series of independent triangles. Like points and line segments, polygon rasterization is controlled by several variables in the VkPipelineRasterizationStateCreateInfo structure.

#### 26.11.1. Basic Polygon Rasterization

The first step of polygon rasterization is to determine whether the triangle is back-facing or front-facing. This determination is made based on the sign of the (clipped or unclipped) polygon’s area computed in framebuffer coordinates. One way to compute this area is:

\[a = -{1 \over 2}\sum_{i=0}^{n-1} x_f^i y_f^{i \oplus 1} - x_f^{i \oplus 1} y_f^i\]

where \(x_f^i\) and \(y_f^i\) are the x and y framebuffer coordinates of the ith vertex of the n-vertex polygon (vertices are numbered starting at zero for the purposes of this computation) and i ⊕ 1 is (i + 1) mod n.

The interpretation of the sign of a is determined by the VkPipelineRasterizationStateCreateInfo::`frontFace` property of the currently active pipeline. Possible values are:

    typedef enum VkFrontFace {
        VK_FRONT_FACE_COUNTER_CLOCKWISE = 0,
        VK_FRONT_FACE_CLOCKWISE = 1,
        VK_FRONT_FACE_MAX_ENUM = 0x7FFFFFFF
    } VkFrontFace;

- `VK_FRONT_FACE_COUNTER_CLOCKWISE` specifies that a triangle with positive area is considered front-facing.

- `VK_FRONT_FACE_CLOCKWISE` specifies that a triangle with negative area is considered front-facing.

Any triangle which is not front-facing is back-facing, including zero-area triangles.

Once the orientation of triangles is determined, they are culled according to the VkPipelineRasterizationStateCreateInfo::`cullMode` property of the currently active pipeline. Possible values are:

    typedef enum VkCullModeFlagBits {
        VK_CULL_MODE_NONE = 0,
        VK_CULL_MODE_FRONT_BIT = 0x00000001,
        VK_CULL_MODE_BACK_BIT = 0x00000002,
        VK_CULL_MODE_FRONT_AND_BACK = 0x00000003,
        VK_CULL_MODE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkCullModeFlagBits;

- `VK_CULL_MODE_NONE` specifies that no triangles are discarded

- `VK_CULL_MODE_FRONT_BIT` specifies that front-facing triangles are discarded

- `VK_CULL_MODE_BACK_BIT` specifies that back-facing triangles are discarded

- `VK_CULL_MODE_FRONT_AND_BACK` specifies that all triangles are discarded.

Following culling, fragments are produced for any triangles which have not been discarded.

    typedef VkFlags VkCullModeFlags;

`VkCullModeFlags` is a bitmask type for setting a mask of zero or more VkCullModeFlagBits.

The rule for determining which fragments are produced by polygon rasterization is called point sampling. The two-dimensional projection obtained by taking the x and y framebuffer coordinates of the polygon’s vertices is formed. Fragments are produced for any fragment area groups of pixels for which any sample points lie inside of this polygon. Coverage bits that correspond to sample points that satisfy the point sampling criteria are 1, other coverage bits are 0. Special treatment is given to a sample whose sample location lies on a polygon edge. In such a case, if two polygons lie on either side of a common edge (with identical endpoints) on which a sample point lies, then exactly one of the polygons must result in a covered sample for that fragment during rasterization. As for the data associated with each fragment produced by rasterizing a polygon, we begin by specifying how these values are produced for fragments in a triangle.

Barycentric coordinates are a set of three numbers, a, b, and c, each in the range [0,1], with a + b + c = 1. These coordinates uniquely specify any point p within the triangle or on the triangle’s boundary as

  p = a pa + b pb + c pc

where pa, pb, and pc are the vertices of the triangle. a, b, and c are determined by:

\[a = {{\mathrm{A}(p p_b p_c)} \over {\mathrm{A}(p_a p_b p_c)}}, \quad b = {{\mathrm{A}(p p_a p_c)} \over {\mathrm{A}(p_a p_b p_c)}}, \quad c = {{\mathrm{A}(p p_a p_b)} \over {\mathrm{A}(p_a p_b p_c)}},\]

where A(lmn) denotes the area in framebuffer coordinates of the triangle with vertices l, m, and n.

Denote an associated datum at pa, pb, or pc as fa, fb, or fc, respectively.

The value of an associated datum f for a fragment produced by rasterizing a triangle, whether it be a shader output or the clip w coordinate, must be determined using perspective interpolation:

\[f = { a {f_a / w_a} + b {f_b / w_b} + c {f_c / w_c} } \over { {a / w_a} + {b / w_b} + {c / w_c} }\]

where wa, wb, and wc are the clip w coordinates of pa, pb, and pc, respectively. a, b, and c are the barycentric coordinates of the location at which the data are produced - this must be the location of the fragment center or the location of a sample. When `rasterizationSamples` is `VK_SAMPLE_COUNT_1_BIT`, the fragment center must be used.

Depth values for triangles must be determined using linear interpolation:

  z = a za + b zb + c zc

where za, zb, and zc are the depth values of pa, pb, and pc, respectively.

The `NoPerspective` and `Flat` interpolation decorations can be used with fragment shader inputs to declare how they are interpolated. When neither decoration is applied, perspective interpolation is performed as described above. When the `NoPerspective` decoration is used, linear interpolation is performed in the same fashion as for depth values, as described above. When the `Flat` decoration is used, no interpolation is performed, and outputs are taken from the corresponding input value of the provoking vertex corresponding to that primitive.

When the `VK_AMD_shader_explicit_vertex_parameter` device extension is enabled the `CustomInterpAMD` interpolation decoration can also be used with fragment shader inputs which indicate that the decorated inputs can only be accessed by the extended instruction `InterpolateAtVertexAMD` and allows accessing the value of the inputs for individual vertices of the primitive.

When the `fragmentShaderBarycentric` feature is enabled, the `PerVertexNV` interpolation decoration can also be used with fragment shader inputs which indicate that the decorated inputs are not interpolated and can only be accessed using an extra array dimension, where the extra index identifies one of the vertices of the primitive that produced the fragment.

For a polygon with more than three edges, such as are produced by clipping a triangle, a convex combination of the values of the datum at the polygon’s vertices must be used to obtain the value assigned to each fragment produced by the rasterization algorithm. That is, it must be the case that at every fragment

\[f = \sum_{i=1}^{n} a_i f_i\]

where n is the number of vertices in the polygon and fi is the value of f at vertex i. For each i, 0 ≤ ai ≤ 1 and \(\sum_{i=1}^{n}a_i = 1\). The values of ai may differ from fragment to fragment, but at vertex i, ai = 1 and aj = 0 for j ≠ i.

| Note One algorithm that achieves the required behavior is to triangulate a polygon (without adding any vertices) and then treat each triangle individually as already discussed. A scan-line rasterizer that linearly interpolates data along each edge and then linearly interpolates data across each horizontal span from edge to edge also satisfies the restrictions (in this case, the numerator and denominator of equation [triangle_perspective_interpolation] are iterated independently and a division performed for each fragment).

#### 26.11.2. Polygon Mode

Possible values of the VkPipelineRasterizationStateCreateInfo::`polygonMode` property of the currently active pipeline, specifying the method of rasterization for polygons, are:

    typedef enum VkPolygonMode {
        VK_POLYGON_MODE_FILL = 0,
        VK_POLYGON_MODE_LINE = 1,
        VK_POLYGON_MODE_POINT = 2,
        VK_POLYGON_MODE_FILL_RECTANGLE_NV = 1000153000,
        VK_POLYGON_MODE_MAX_ENUM = 0x7FFFFFFF
    } VkPolygonMode;

- `VK_POLYGON_MODE_POINT` specifies that polygon vertices are drawn as points.

- `VK_POLYGON_MODE_LINE` specifies that polygon edges are drawn as line segments.

- `VK_POLYGON_MODE_FILL` specifies that polygons are rendered using the polygon rasterization rules in this section.

- `VK_POLYGON_MODE_FILL_RECTANGLE_NV` specifies that polygons are rendered using polygon rasterization rules, modified to consider a sample within the primitive if the sample location is inside the axis-aligned bounding box of the triangle after projection. Note that the barycentric weights used in attribute interpolation can extend outside the range [0,1] when these primitives are shaded. Special treatment is given to a sample position on the boundary edge of the bounding box. In such a case, if two rectangles lie on either side of a common edge (with identical endpoints) on which a sample position lies, then exactly one of the triangles must produce a fragment that covers that sample during rasterization.

  Polygons rendered in `VK_POLYGON_MODE_FILL_RECTANGLE_NV` mode may be clipped by the frustum or by user clip planes. If clipping is applied, the triangle is culled rather than clipped.

  Area calculation and facingness are determined for `VK_POLYGON_MODE_FILL_RECTANGLE_NV` mode using the triangle’s vertices.

These modes affect only the final rasterization of polygons: in particular, a polygon’s vertices are shaded and the polygon is clipped and possibly culled before these modes are applied.

#### 26.11.3. Depth Bias

The depth values of all fragments generated by the rasterization of a polygon can be offset by a single value that is computed for that polygon. This behavior is controlled by the `depthBiasEnable`, `depthBiasConstantFactor`, `depthBiasClamp`, and `depthBiasSlopeFactor` members of VkPipelineRasterizationStateCreateInfo, or by the corresponding parameters to the `vkCmdSetDepthBias` command if depth bias state is dynamic.

    void vkCmdSetDepthBias(
        VkCommandBuffer                             commandBuffer,
        float                                       depthBiasConstantFactor,
        float                                       depthBiasClamp,
        float                                       depthBiasSlopeFactor);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `depthBiasConstantFactor` is a scalar factor controlling the constant depth value added to each fragment.

- `depthBiasClamp` is the maximum (or minimum) depth bias of a fragment.

- `depthBiasSlopeFactor` is a scalar factor applied to a fragment’s slope in depth bias calculations.

If `depthBiasEnable` is `VK_FALSE`, no depth bias is applied and the fragment’s depth values are unchanged.

`depthBiasSlopeFactor` scales the maximum depth slope of the polygon, and `depthBiasConstantFactor` scales an implementation-dependent constant that relates to the usable resolution of the depth buffer. The resulting values are summed to produce the depth bias value which is then clamped to a minimum or maximum value specified by `depthBiasClamp`. `depthBiasSlopeFactor`, `depthBiasConstantFactor`, and `depthBiasClamp` can each be positive, negative, or zero.

The maximum depth slope m of a triangle is

\[m = \sqrt{ \left({{\partial z_f} \over {\partial x_f}}\right)^2 + \left({{\partial z_f} \over {\partial y_f}}\right)^2}\]

where (xf, yf, zf) is a point on the triangle. m may be approximated as

\[m = \max\left( \left| { {\partial z_f} \over {\partial x_f} } \right|, \left| { {\partial z_f} \over {\partial y_f} } \right| \right).\]

The minimum resolvable difference r is an implementation-dependent parameter that depends on the depth buffer representation. It is the smallest difference in framebuffer coordinate z values that is guaranteed to remain distinct throughout polygon rasterization and in the depth buffer. All pairs of fragments generated by the rasterization of two polygons with otherwise identical vertices, but `z`f values that differ by r, will have distinct depth values.

For fixed-point depth buffer representations, r is constant throughout the range of the entire depth buffer. For floating-point depth buffers, there is no single minimum resolvable difference. In this case, the minimum resolvable difference for a given polygon is dependent on the maximum exponent, e, in the range of z values spanned by the primitive. If n is the number of bits in the floating-point mantissa, the minimum resolvable difference, r, for the given primitive is defined as

  r = 2e-n

If a triangle is rasterized using the `VK_POLYGON_MODE_FILL_RECTANGLE_NV` polygon mode, then this minimum resolvable difference may not be resolvable for samples outside of the triangle, where the depth is extrapolated.

If no depth buffer is present, r is undefined.

The bias value o for a polygon is

\[\begin{aligned} o &= \mathrm{dbclamp}( m \times \mathtt{depthBiasSlopeFactor} + r \times \mathtt{depthBiasConstantFactor} ) \\ \text{where} &\quad \mathrm{dbclamp}(x) = \begin{cases} x & \mathtt{depthBiasClamp} = 0 \ \text{or}\ \texttt{NaN} \\ \min(x, \mathtt{depthBiasClamp}) & \mathtt{depthBiasClamp} > 0 \\ \max(x, \mathtt{depthBiasClamp}) & \mathtt{depthBiasClamp} < 0 \\ \end{cases} \end{aligned}\]

m is computed as described above. If the depth buffer uses a fixed-point representation, m is a function of depth values in the range [0,1], and o is applied to depth values in the same range.

For fixed-point depth buffers, fragment depth values are always limited to the range [0,1] by clamping after depth bias addition is performed. Unless the `VK_EXT_depth_range_unrestricted` extension is enabled, fragment depth values are clamped even when the depth buffer uses a floating-point representation.

Valid Usage

- If the depth bias clamping feature is not enabled, `depthBiasClamp` must be `0.0`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics |

#### 26.11.4. Conservative Rasterization

Polygon rasterization can be made conservative by setting `conservativeRasterizationMode` to `VK_CONSERVATIVE_RASTERIZATION_MODE_OVERESTIMATE_EXT` or `VK_CONSERVATIVE_RASTERIZATION_MODE_UNDERESTIMATE_EXT` in `VkPipelineRasterizationConservativeStateCreateInfoEXT`. The `VkPipelineRasterizationConservativeStateCreateInfoEXT` state is set by adding this structure to the `pNext` chain of a `VkPipelineRasterizationStateCreateInfo` structure when creating the graphics pipeline. Enabling these modes also affects line and point rasterization if the implementation sets `VkPhysicalDeviceConservativeRasterizationPropertiesEXT`::`conservativePointAndLineRasterization` to `VK_TRUE`.

`VkPipelineRasterizationConservativeStateCreateInfoEXT` is defined as:

    typedef struct VkPipelineRasterizationConservativeStateCreateInfoEXT {
        VkStructureType                                           sType;
        const void*                                               pNext;
        VkPipelineRasterizationConservativeStateCreateFlagsEXT    flags;
        VkConservativeRasterizationModeEXT                        conservativeRasterizationMode;
        float                                                     extraPrimitiveOverestimationSize;
    } VkPipelineRasterizationConservativeStateCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `conservativeRasterizationMode` is the conservative rasterization mode to use.

- `extraPrimitiveOverestimationSize` is the extra size in pixels to increase the generating primitive during conservative rasterization at each of its edges in `X` and `Y` equally in screen space beyond the base overestimation specified in `VkPhysicalDeviceConservativeRasterizationPropertiesEXT`::`primitiveOverestimationSize`.

Valid Usage

- `extraPrimitiveOverestimationSize` must be in the range of `0.0` to `VkPhysicalDeviceConservativeRasterizationPropertiesEXT`::`maxExtraPrimitiveOverestimationSize` inclusive

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_CONSERVATIVE_STATE_CREATE_INFO_EXT`

- `flags` must be `0`

- `conservativeRasterizationMode` must be a valid VkConservativeRasterizationModeEXT value

    typedef VkFlags VkPipelineRasterizationConservativeStateCreateFlagsEXT;

`VkPipelineRasterizationConservativeStateCreateFlagsEXT` is a bitmask type for setting a mask, but is currently reserved for future use.

Possible values of VkPipelineRasterizationConservativeStateCreateInfoEXT::`conservativeRasterizationMode`, specifying the conservative rasterization mode are:

    typedef enum VkConservativeRasterizationModeEXT {
        VK_CONSERVATIVE_RASTERIZATION_MODE_DISABLED_EXT = 0,
        VK_CONSERVATIVE_RASTERIZATION_MODE_OVERESTIMATE_EXT = 1,
        VK_CONSERVATIVE_RASTERIZATION_MODE_UNDERESTIMATE_EXT = 2,
        VK_CONSERVATIVE_RASTERIZATION_MODE_MAX_ENUM_EXT = 0x7FFFFFFF
    } VkConservativeRasterizationModeEXT;

- `VK_CONSERVATIVE_RASTERIZATION_MODE_DISABLED_EXT` specifies that conservative rasterization is disabled and rasterization proceeds as normal.

- `VK_CONSERVATIVE_RASTERIZATION_MODE_OVERESTIMATE_EXT` specifies that conservative rasterization is enabled in overestimation mode.

- `VK_CONSERVATIVE_RASTERIZATION_MODE_UNDERESTIMATE_EXT` specifies that conservative rasterization is enabled in underestimation mode.

When overestimate conservative rasterization is enabled, rather than evaluating coverage at individual sample locations, a determination is made of whether any portion of the pixel (including its edges and corners) is covered by the primitive. If any portion of the pixel is covered, then all bits of the coverage sample mask for the fragment corresponding to that pixel are enabled. If the render pass has a fragment density map attachment and any bit of the coverage sample mask for the fragment is enabled, then all bits of the coverage sample mask for the fragment are enabled.

If the implementation supports `VkPhysicalDeviceConservativeRasterizationPropertiesEXT`::`conservativeRasterizationPostDepthCoverage` and the `PostDepthCoverage` execution mode is specified the `SampleMask` built-in input variable will reflect the coverage after the early per-fragment depth and stencil tests are applied.

For the purposes of evaluating which pixels are covered by the primitive, implementations can increase the size of the primitive by up to `VkPhysicalDeviceConservativeRasterizationPropertiesEXT`::`primitiveOverestimationSize` pixels at each of the primitive edges. This may increase the number of fragments generated by this primitive and represents an overestimation of the pixel coverage.

This overestimation size can be increased further by setting the `extraPrimitiveOverestimationSize` value above `0.0` in steps of `VkPhysicalDeviceConservativeRasterizationPropertiesEXT`::`extraPrimitiveOverestimationSizeGranularity` up to and including `VkPhysicalDeviceConservativeRasterizationPropertiesEXT`::`extraPrimitiveOverestimationSize`. This will: further increase the number of fragments generated by this primitive.

The actual precision of the overestimation size used for conservative rasterization may vary between implementations and produce results that only approximate the `primitiveOverestimationSize` and `extraPrimitiveOverestimationSizeGranularity` properties. Implementations may especially vary these approximations when the render pass has a fragment density map and the fragment area covers multiple pixels.

For triangles if `VK_CONSERVATIVE_RASTERIZATION_MODE_OVERESTIMATE_EXT` is enabled, fragments will be generated if the primitive area covers any portion of any pixel inside the fragment area, including their edges or corners. The tie-breaking rule described in Basic Polygon Rasterization does not apply during conservative rasterization and coverage is set for all fragments generated from shared edges of polygons. Degenerate triangles that evaluate to zero area after rasterization, even for pixels containing a vertex or edge of the zero-area polygon, will be culled if `VkPhysicalDeviceConservativeRasterizationPropertiesEXT`::`degenerateTrianglesRasterized` is `VK_FALSE` or will generate fragments if `degenerateTrianglesRasterized` is `VK_TRUE`. The fragment input values for these degenerate triangles take their attribute and depth values from the provoking vertex. Degenerate triangles are considered backfacing and the application can enable backface culling if desired. Triangles that are zero area before rasterization may be culled regardless.

For lines if `VK_CONSERVATIVE_RASTERIZATION_MODE_OVERESTIMATE_EXT` is enabled, and the implementation sets `VkPhysicalDeviceConservativeRasterizationPropertiesEXT`::`conservativePointAndLineRasterization` to `VK_TRUE`, fragments will be generated if the line covers any portion of any pixel inside the fragment area, including their edges or corners. Degenerate lines that evaluate to zero length after rasterization will be culled if `VkPhysicalDeviceConservativeRasterizationPropertiesEXT`::`degenerateLinesRasterized` is `VK_FALSE` or will generate fragments if `degenerateLinesRasterized` is `VK_TRUE`. The fragments input values for these degenerate lines take their attribute and depth values from the provoking vertex. Lines that are zero length before rasterization may be culled regardless.

For points if `VK_CONSERVATIVE_RASTERIZATION_MODE_OVERESTIMATE_EXT` is enabled, and the implementation sets `VkPhysicalDeviceConservativeRasterizationPropertiesEXT`::`conservativePointAndLineRasterization` to `VK_TRUE`, fragments will be generated if the point square covers any portion of any pixel inside the fragment area, including their edges or corners.

When underestimate conservative rasterization is enabled, rather than evaluating coverage at individual sample locations, a determination is made of whether all of the pixel (including its edges and corners) is covered by the primitive. If the entire pixel is covered, then a fragment is generated with all bits of its coverage sample mask corresponding to the pixel enabled, otherwise the pixel is not considered covered even if some portion of the pixel is covered. The fragment is discarded if no pixels inside the fragment area are considered covered. If the render pass has a fragment density map attachment and any pixel inside the fragment area is not considered covered, then the fragment is discarded even if some pixels are considered covered.

If the implementation supports `VkPhysicalDeviceConservativeRasterizationPropertiesEXT`::`conservativeRasterizationPostDepthCoverage` and the `PostDepthCoverage` execution mode is specified the `SampleMask` built-in input variable will reflect the coverage after the early per-fragment depth and stencil tests are applied.

For triangles, if `VK_CONSERVATIVE_RASTERIZATION_MODE_UNDERESTIMATE_EXT` is enabled, fragments will only be generated if any pixel inside the fragment area is fully covered by the generating primitive, including its edges and corners.

For lines, if `VK_CONSERVATIVE_RASTERIZATION_MODE_UNDERESTIMATE_EXT` is enabled, fragments will be generated if any pixel inside the fragment area, including its edges and corners, are entirely covered by the line.

For points, if `VK_CONSERVATIVE_RASTERIZATION_MODE_UNDERESTIMATE_EXT` is enabled, fragments will only be generated if the point square covers the entirety of any pixel square inside the fragment area, including its edges or corners.

If the render pass has a fragment density map and `VK_CONSERVATIVE_RASTERIZATION_MODE_UNDERESTIMATE_EXT` is enabled, fragments will only be generated if the entirety of all pixels inside the fragment area are covered by the generating primitive, line, or point.

For both overestimate and underestimate conservative rasterization modes a fragment has all of its pixel squares fully covered by the generating primitive must set `FullyCoveredEXT` to `VK_TRUE` if the implementation enables the `VkPhysicalDeviceConservativeRasterizationPropertiesEXT`::`fullyCoveredFragmentShaderInputVariable` feature.

When the use of a shading rate image results in fragments covering multiple pixels, coverage for conservative rasterization is still evaluated on a per-pixel basis and may result in fragments with partial coverage. For fragment shader inputs decorated with `FullyCoveredEXT`, a fragment is considered fully covered if and only if all pixels in the fragment are fully covered by the generating primitive.

## 27. Fragment Operations

Fragment operations execute on a per-fragment or per-sample basis, affecting whether or how a fragment or sample is written to the framebuffer. Some operations execute before fragment shading, and others after. Fragment operations always adhere to rasterization order.

### 27.1. Early Per-Fragment Tests

Once fragments are produced by rasterization, a number of per-fragment operations are performed prior to fragment shader execution. If a fragment is discarded during any of these operations, it will not be processed by any subsequent stage, including fragment shader execution.

The scissor test, exclusive scissor test, and sample mask generation are always performed during early fragment tests.

Fragment operations are performed in the following order:

- the discard rectangles test (see Discard Rectangles Test)

- the scissor test (see Scissor Test)

- the exclusive scissor test (see Exclusive Scissor Test)

- multisample fragment operations (see Sample Mask)

If early per-fragment operations are enabled by the fragment shader, these operations are also performed:

- Depth bounds test

- Stencil test

- Depth test

- Representative fragment test

- Sample counting for occlusion queries

If post-depth coverage operation is enabled by the fragment shader, the `SampleMask` coverage is determined after the early stencil and depth tests.

### 27.2. Discard Rectangles Test

The discard rectangles test determines if fragment’s framebuffer coordinates (xf,yf) are inclusive or exclusive to a set of discard-space rectangles. The discard rectangles are set with the `VkPipelineDiscardRectangleStateCreateInfoEXT` pipeline state, which is defined as:

    typedef struct VkPipelineDiscardRectangleStateCreateInfoEXT {
        VkStructureType                                  sType;
        const void*                                      pNext;
        VkPipelineDiscardRectangleStateCreateFlagsEXT    flags;
        VkDiscardRectangleModeEXT                        discardRectangleMode;
        uint32_t                                         discardRectangleCount;
        const VkRect2D*                                  pDiscardRectangles;
    } VkPipelineDiscardRectangleStateCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `discardRectangleMode` is the mode used to determine whether fragments that lie within the discard rectangle are discarded or not.

- `discardRectangleCount` is the number of discard rectangles used by the pipeline.

- `pDiscardRectangles` is a pointer to an array of VkRect2D structures, defining the discard rectangles. If the discard rectangle state is dynamic, this member is ignored.

Valid Usage

- `discardRectangleCount` must be between `0` and `VkPhysicalDeviceDiscardRectanglePropertiesEXT`::`maxDiscardRectangles`, inclusive

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_DISCARD_RECTANGLE_STATE_CREATE_INFO_EXT`

- `flags` must be `0`

- `discardRectangleMode` must be a valid VkDiscardRectangleModeEXT value

    typedef VkFlags VkPipelineDiscardRectangleStateCreateFlagsEXT;

`VkPipelineDiscardRectangleStateCreateFlagsEXT` is a bitmask type for setting a mask, but is currently reserved for future use.

The `VkPipelineDiscardRectangleStateCreateInfoEXT` state is set by adding this structure to the `pNext` chain of a `VkGraphicsPipelineCreateInfo` structure and setting the graphics pipeline state with vkCreateGraphicsPipelines.

If the bound pipeline state object was not created with the `VK_DYNAMIC_STATE_DISCARD_RECTANGLE_EXT` dynamic state enabled, discard rectangles are specified using the `pDiscardRectangles` member of `VkPipelineDiscardRectangleStateCreateInfoEXT` linked to the pipeline state object.

If the pipeline state object was created with the `VK_DYNAMIC_STATE_DISCARD_RECTANGLE_EXT` dynamic state enabled, the discard rectangles are dynamically set and changed with the command:

    void vkCmdSetDiscardRectangleEXT(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    firstDiscardRectangle,
        uint32_t                                    discardRectangleCount,
        const VkRect2D*                             pDiscardRectangles);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `firstDiscardRectangle` is the index of the first discard rectangle whose state is updated by the command.

- `discardRectangleCount` is the number of discard rectangles whose state are updated by the command.

- `pDiscardRectangles` is a pointer to an array of VkRect2D structures specifying discard rectangles.

The discard rectangle taken from element i of `pDiscardRectangles` replace the current state for the discard rectangle index `firstDiscardRectangle` + i, for i in [0, `discardRectangleCount`).

Valid Usage

- The sum of `firstDiscardRectangle` and `discardRectangleCount` must be less than or equal to VkPhysicalDeviceDiscardRectanglePropertiesEXT::`maxDiscardRectangles`

- The `x` and `y` member of `offset` in each VkRect2D element of `pDiscardRectangles` must be greater than or equal to `0`

- Evaluation of (`offset.x` + `extent.width`) in each VkRect2D element of `pDiscardRectangles` must not cause a signed integer addition overflow

- Evaluation of (`offset.y` + `extent.height`) in each VkRect2D element of `pDiscardRectangles` must not cause a signed integer addition overflow

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pDiscardRectangles` must be a valid pointer to an array of `discardRectangleCount` VkRect2D structures

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- `discardRectangleCount` must be greater than `0`

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics |

The `VkOffset2D`::`x` and `VkOffset2D`::`y` values of the discard rectangle `VkRect2D` specify the upper-left origin of the discard rectangle box. The lower-right corner of the discard rectangle box is specified as the `VkExtent2D`::`width` and `VkExtent2D`::`height` from the upper-left origin.

If `offset.x` ≤ xf < `offset.x` + `extent.width` and `offset.y` ≤ yf < `offset.y` + `extent.height` for the selected discard rectangle, then the fragment is within the discard rectangle box. When the discard rectangle mode is `VK_DISCARD_RECTANGLE_MODE_INCLUSIVE_EXT` a fragment within at least one of the active discard rectangle boxes passes the discard rectangle test; otherwise the fragment fails the discard rectangle test and is discarded. When the discard rectangle mode is `VK_DISCARD_RECTANGLE_MODE_EXCLUSIVE_EXT` a fragment within at least one of the active discard rectangle boxes fails the discard rectangle test, and the fragment is discarded; otherwise the fragment passes the discard rectangles test. The discard rectangles test only applies to drawing commands, not to other commands like clears or copies.

Possible values of VkPipelineDiscardRectangleStateCreateInfoEXT::`discardRectangleMode`, specifying the behavior of the discard rectangle test, are:

    typedef enum VkDiscardRectangleModeEXT {
        VK_DISCARD_RECTANGLE_MODE_INCLUSIVE_EXT = 0,
        VK_DISCARD_RECTANGLE_MODE_EXCLUSIVE_EXT = 1,
        VK_DISCARD_RECTANGLE_MODE_MAX_ENUM_EXT = 0x7FFFFFFF
    } VkDiscardRectangleModeEXT;

- `VK_DISCARD_RECTANGLE_MODE_INCLUSIVE_EXT` specifies that a fragment within any discard rectangle satisfies the test.

- `VK_DISCARD_RECTANGLE_MODE_EXCLUSIVE_EXT` specifies that a fragment not within any of the discard rectangles satisfies the test.

When the use of a shading rate image results in a fragment covering multiple pixels, the discard rectangle test is performed independently for each pixel in the fragment. If a pixel covered by a fragment fails the discard rectangle test, all samples in the fragment associated with that pixel are treated as not covered. If the discard rectangle test results in a fragment with no samples covered, that fragment is discarded.

### 27.3. Scissor Test

The scissor test determines if a fragment’s framebuffer coordinates (xf,yf) lie within the scissor rectangle corresponding to the viewport index (see Controlling the Viewport) used by the primitive that generated the fragment. If the pipeline state object is created without `VK_DYNAMIC_STATE_SCISSOR` enabled then the scissor rectangles are set by the VkPipelineViewportStateCreateInfo state of the pipeline state object. Otherwise, to dynamically set the scissor rectangles call:

    void vkCmdSetScissor(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    firstScissor,
        uint32_t                                    scissorCount,
        const VkRect2D*                             pScissors);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `firstScissor` is the index of the first scissor whose state is updated by the command.

- `scissorCount` is the number of scissors whose rectangles are updated by the command.

- `pScissors` is a pointer to an array of VkRect2D structures defining scissor rectangles.

The scissor rectangles taken from element i of `pScissors` replace the current state for the scissor index `firstScissor` + i, for i in [0, `scissorCount`).

Each scissor rectangle is described by a VkRect2D structure, with the `offset.x` and `offset.y` values determining the upper left corner of the scissor rectangle, and the `extent.width` and `extent.height` values determining the size in pixels.

If a render pass transform is enabled, the (`offset.x` and `offset.y`) and (`extent.width` and `extent.height`) values are transformed as described in render pass transform before participating in the scissor test.

Valid Usage

- `firstScissor` must be less than `VkPhysicalDeviceLimits`::`maxViewports`

- The sum of `firstScissor` and `scissorCount` must be between `1` and `VkPhysicalDeviceLimits`::`maxViewports`, inclusive

- If the multiple viewports feature is not enabled, `firstScissor` must be `0`

- If the multiple viewports feature is not enabled, `scissorCount` must be `1`

- The `x` and `y` members of `offset` member of any element of `pScissors` must be greater than or equal to `0`

- Evaluation of (`offset.x` + `extent.width`) must not cause a signed integer addition overflow for any element of `pScissors`

- Evaluation of (`offset.y` + `extent.height`) must not cause a signed integer addition overflow for any element of `pScissors`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pScissors` must be a valid pointer to an array of `scissorCount` VkRect2D structures

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- `scissorCount` must be greater than `0`

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics |

If `offset.x` ≤ xf < `offset.x` + `extent.width` and `offset.y` ≤ yf < `offset.y` + `extent.height` for the selected scissor rectangle, then the scissor test passes. Otherwise, the test fails and the fragment is discarded. For points, lines, and polygons, the scissor rectangle for a primitive is selected in the same manner as the viewport (see Controlling the Viewport). The scissor rectangles test only applies to drawing commands, not to other commands like clears or copies.

It is legal for `offset.x` + `extent.width` or `offset.y` + `extent.height` to exceed the dimensions of the framebuffer - the scissor test still applies as defined above. Rasterization does not produce fragments outside of the framebuffer, so such fragments never have the scissor test performed on them.

The scissor test is always performed. Applications can effectively disable the scissor test by specifying a scissor rectangle that encompasses the entire framebuffer.

When the use of a shading rate image results in a fragment covering multiple pixels, the scissor test is performed independently for each pixel in the fragment. If a pixel covered by a fragment fails the scissor test, all samples in the fragment associated with that pixel are treated as not covered. If the scissor test results in a fragment with no samples covered, that fragment is discarded.

### 27.4. Exclusive Scissor Test

The exclusive scissor test determines if a pixel’s framebuffer coordinates (xf,yf) lie outside the exclusive scissor rectangle corresponding to the viewport index (see Controlling the Viewport) used by the primitive that generated the fragment. The exclusive scissor test behaves identically to the scissor test, except that it passes only if the pixel is outside the rectangle instead of passing if the pixel is inside the rectangle.

If the `pNext` chain of `VkPipelineViewportStateCreateInfo` includes a `VkPipelineViewportExclusiveScissorStateCreateInfoNV` structure, then that structure includes parameters that affect the exclusive scissor test.

The `VkPipelineViewportExclusiveScissorStateCreateInfoNV` structure is defined as:

    typedef struct VkPipelineViewportExclusiveScissorStateCreateInfoNV {
        VkStructureType    sType;
        const void*        pNext;
        uint32_t           exclusiveScissorCount;
        const VkRect2D*    pExclusiveScissors;
    } VkPipelineViewportExclusiveScissorStateCreateInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `exclusiveScissorCount` is the number of exclusive scissor rectangles used by the pipeline.

- `pExclusiveScissors` is a pointer to an array of VkRect2D structures defining exclusive scissor rectangles. If the exclusive scissor state is dynamic, this member is ignored.

If this structure is not present, `exclusiveScissorCount` is considered to be `0` and the exclusive scissor test is disabled.

Valid Usage

- If the multiple viewports feature is not enabled, `exclusiveScissorCount` must be `0` or `1`

- `exclusiveScissorCount` must be less than or equal to `VkPhysicalDeviceLimits`::`maxViewports`

- `exclusiveScissorCount` must be `0` or identical to the `viewportCount` member of `VkPipelineViewportStateCreateInfo`

- If no element of the `pDynamicStates` member of `pDynamicState` is `VK_DYNAMIC_STATE_EXCLUSIVE_SCISSOR_NV` and `exclusiveScissorCount` is not `0`, `pExclusiveScissors` must be a valid pointer to an array of `exclusiveScissorCount` `VkRect2D` structures

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_EXCLUSIVE_SCISSOR_STATE_CREATE_INFO_NV`

- If `exclusiveScissorCount` is not `0`, and `pExclusiveScissors` is not `NULL`, `pExclusiveScissors` must be a valid pointer to an array of `exclusiveScissorCount` VkRect2D structures

If the pipeline state object is created with `VK_DYNAMIC_STATE_EXCLUSIVE_SCISSOR_NV` enabled, then the exclusive scissor rectangles are set by:

    void vkCmdSetExclusiveScissorNV(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    firstExclusiveScissor,
        uint32_t                                    exclusiveScissorCount,
        const VkRect2D*                             pExclusiveScissors);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `firstExclusiveScissor` is the index of the first exclusive scissor rectangle whose state is updated by the command.

- `exclusiveScissorCount` is the number of exclusive scissor rectangles updated by the command.

- `pExclusiveScissors` is a pointer to an array of VkRect2D structures defining exclusive scissor rectangles.

The scissor rectangles taken from element i of `pExclusiveScissors` replace the current state for the scissor index `firstExclusiveScissor` + i, for i in [0, `exclusiveScissorCount`).

Each scissor rectangle is described by a VkRect2D structure, with the `offset.x` and `offset.y` values determining the upper left corner of the scissor rectangle, and the `extent.width` and `extent.height` values determining the size in pixels.

Valid Usage

- The exclusive scissor feature must be enabled.

- `firstExclusiveScissor` must be less than `VkPhysicalDeviceLimits`::`maxViewports`

- The sum of `firstExclusiveScissor` and `exclusiveScissorCount` must be between `1` and `VkPhysicalDeviceLimits`::`maxViewports`, inclusive

- If the multiple viewports feature is not enabled, `firstExclusiveScissor` must be `0`

- If the multiple viewports feature is not enabled, `exclusiveScissorCount` must be `1`

- The `x` and `y` members of `offset` in each member of `pExclusiveScissors` must be greater than or equal to `0`

- Evaluation of (`offset.x` + `extent.width`) for each member of `pExclusiveScissors` must not cause a signed integer addition overflow

- Evaluation of (`offset.y` + `extent.height`) for each member of `pExclusiveScissors` must not cause a signed integer addition overflow

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pExclusiveScissors` must be a valid pointer to an array of `exclusiveScissorCount` VkRect2D structures

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

- `exclusiveScissorCount` must be greater than `0`

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics |

If `offset.x` ≤ xf < `offset.x` + `extent.width` and `offset.y` ≤ yf < `offset.y` + `extent.height` for the selected exclusive scissor rectangle, then the exclusive scissor test fails and the fragment is discarded. Otherwise, the exclusive scissor test passes. For points, lines, and polygons, the exclusive scissor rectangle for a primitive is selected in the same manner as the viewport (see Controlling the Viewport). The exclusive scissor test only applies to drawing commands, not to other commands like clears or copies.

It is legal for `offset.x` + `extent.width` or `offset.y` + `extent.height` to exceed the dimensions of the framebuffer - the exclusive scissor test still applies as defined above. Rasterization does not produce fragments outside of the framebuffer, so such fragments never have the exclusive scissor test performed on them.

The exclusive scissor test is performed if and only if the current pipeline was created with a non-zero `exclusiveScissorCount`. Applications can effectively disable the exclusive scissor test for specific viewports by specifying a scissor rectangle with a width or height of zero.

When the use of a shading rate image results in a fragment covering multiple pixels, the exclusive scissor test is performed independently for each pixel in the fragment. If a pixel covered by a fragment fails the exclusive scissor test, all samples in the fragment associated with that pixel are treated as not covered. If the exclusive scissor test results in a fragment with no samples covered, that fragment is discarded.

### 27.5. Sample Mask

This step modifies fragment coverage values based on the values in the `pSampleMask` array member of VkPipelineMultisampleStateCreateInfo, as described previously in section Graphics Pipelines.

`pSampleMask` contains an array of static coverage information that is `ANDed` with the coverage information generated during rasterization. Bits that are zero disable coverage for the corresponding sample. Bit B of mask word M corresponds to sample 32 × M + B. The array is sized to a length of ⌈ `rasterizationSamples` / 32 ⌉ words. If `pSampleMask` is `NULL`, it is treated as if the mask has all bits enabled, i.e. no coverage is removed from fragments.

The elements of the sample mask array are of type `VkSampleMask`, each representing 32 bits of coverage information:

    typedef uint32_t VkSampleMask;

### 27.6. Early Fragment Test Mode

The depth bounds test, stencil test, depth test, representative fragment test, and occlusion query sample counting are performed before fragment shading if and only if early fragment tests are enabled by the fragment shader (see Early Fragment Tests). When early per-fragment operations are enabled, these operations are performed prior to fragment shader execution, and the stencil buffer, depth buffer, and occlusion query sample counts will be updated accordingly; these operations will not be performed again after fragment shader execution.

If a pipeline’s fragment shader has early fragment tests disabled, these operations are performed only after fragment program execution, in the order described below. If a pipeline does not contain a fragment shader, these operations are performed only once.

If early fragment tests are enabled, any depth value computed by the fragment shader has no effect. Additionally, the depth test (including depth writes), stencil test (including stencil writes) and sample counting operations are performed even for fragments or samples that would be discarded after fragment shader execution due to per-fragment operations such as alpha-to-coverage tests, or due to the fragment being discarded by the shader itself.

### 27.7. Late Per-Fragment Tests

After programmable fragment processing, per-fragment operations are performed before blending and color output to the framebuffer.

A fragment is produced by rasterization with framebuffer coordinates of (xf,yf) and depth z, as described in Rasterization. The fragment is then modified by programmable fragment processing, which adds associated data as described in Shaders. The fragment is then further modified, and possibly discarded by the late per-fragment operations described in this chapter. Finally, if the fragment was not discarded, it is used to update the framebuffer at the fragment’s framebuffer coordinates for any samples that remain covered.

The depth bounds test, stencil test, and depth test are performed for each sample, rather than just once for each fragment. Stencil and depth operations are performed for a sample only if that sample’s fragment coverage bit is a value of 1 when the fragment executes the corresponding stage of the graphics pipeline. If the corresponding coverage bit is 0, no operations are performed for that sample. Failure of the depth bounds, stencil, or depth test results in termination of the processing of that sample by means of disabling coverage for that sample, rather than discarding of the fragment. If, at any point, a fragment’s coverage becomes zero for all samples, then the fragment is discarded. All operations are performed on the depth and stencil values stored in the depth/stencil attachment of the framebuffer. The contents of the color attachments are not modified at this point.

The depth bounds test, stencil test, depth test, and occlusion query operations described in Depth Bounds Test, Stencil Test, Depth Test, Sample Counting are instead performed prior to fragment processing, as described in Early Fragment Test Mode, if requested by the fragment shader.

### 27.8. Mixed attachment samples

When the `VK_AMD_mixed_attachment_samples` extension is enabled, special rules apply to per-fragment operations when the number of samples of the color attachments differs from the number of samples of the depth/stencil attachment used in a subpass.

Let C be the number of color attachment samples and D be the number of depth/stencil attachment samples used by a given subpass.

If C < D then only the first C number of samples are guaranteed to have a corresponding fragment shader invocation and thus a corresponding color output value, unless the fragment shaders produce inputs to the late per-fragment tests (e.g. by outputting to a variable decorated with the `FragDepth` built-in decoration). Implementations are allowed to produce fragment shader invocations for samples with indices greater than or equal to C but (other than potential side effects) the color outputs of fragment shader invocations corresponding to such samples are discarded.

### 27.9. Multisample Coverage

If a fragment shader is active and its entry point’s interface includes a built-in output variable decorated with `SampleMask` and also decorated with `OverrideCoverageNV` the fragment coverage is replaced with the sample mask bits set in the shader. Otherwise if the built-in output variable decorated with `SampleMask` is not also decorated with `OverrideCoverageNV` then the fragment coverage is `ANDed` with the bits of the sample mask to generate a new fragment coverage value. If such a fragment shader did not assign a value to `SampleMask` due to flow of control, the value `ANDed` with the fragment coverage is undefined. If no fragment shader is active, or if the active fragment shader does not include `SampleMask` in its interface, the fragment coverage is not modified.

Next, the fragment alpha and coverage values are modified based on the line coverage factor if the `lineRasterizationMode` member of the VkPipelineRasterizationStateCreateInfo structure is `VK_LINE_RASTERIZATION_MODE_RECTANGULAR_SMOOTH_EXT`, and the `alphaToCoverageEnable` and `alphaToOneEnable` members of the VkPipelineMultisampleStateCreateInfo structure.

All alpha values in this section refer only to the alpha component of the fragment shader output that has a `Location` and `Index` decoration of zero (see the Fragment Output Interface section). If that shader output has an integer or unsigned integer type, then these operations are skipped.

If the `lineRasterizationMode` member of the VkPipelineRasterizationStateCreateInfo structure is `VK_LINE_RASTERIZATION_MODE_RECTANGULAR_SMOOTH_EXT` and the fragment came from a line segment, then the alpha value is replaced by multiplying it by the coverage factor for the fragment computed during smooth line rasterization.

If `alphaToCoverageEnable` is enabled, a temporary coverage value with `rasterizationSamples` bits is generated where each bit is determined by the fragment’s alpha value. The temporary coverage value is then ANDed with the fragment coverage value to generate a new fragment coverage value.

No specific algorithm is specified for converting the alpha value to a temporary coverage mask. It is intended that the number of 1’s in this value be proportional to the alpha value (clamped to [0,1]), with all 1’s corresponding to a value of 1.0 and all 0’s corresponding to 0.0. The algorithm may be different at different framebuffer coordinates.

| Note Using different algorithms at different framebuffer coordinates may help to avoid artifacts caused by regular coverage sample locations.

Next, if `alphaToOneEnable` is enabled, each alpha value is replaced by the maximum representable alpha value for fixed-point color buffers, or by 1.0 for floating-point buffers. Otherwise, the alpha values are not changed.

### 27.10. Depth and Stencil Operations

Pipeline state controlling the depth bounds tests, stencil test, and depth test is specified through the members of the `VkPipelineDepthStencilStateCreateInfo` structure.

The `VkPipelineDepthStencilStateCreateInfo` structure is defined as:

    typedef struct VkPipelineDepthStencilStateCreateInfo {
        VkStructureType                           sType;
        const void*                               pNext;
        VkPipelineDepthStencilStateCreateFlags    flags;
        VkBool32                                  depthTestEnable;
        VkBool32                                  depthWriteEnable;
        VkCompareOp                               depthCompareOp;
        VkBool32                                  depthBoundsTestEnable;
        VkBool32                                  stencilTestEnable;
        VkStencilOpState                          front;
        VkStencilOpState                          back;
        float                                     minDepthBounds;
        float                                     maxDepthBounds;
    } VkPipelineDepthStencilStateCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `depthTestEnable` controls whether depth testing is enabled.

- `depthWriteEnable` controls whether depth writes are enabled when `depthTestEnable` is `VK_TRUE`. Depth writes are always disabled when `depthTestEnable` is `VK_FALSE`.

- `depthCompareOp` is the comparison operator used in the depth test.

- `depthBoundsTestEnable` controls whether depth bounds testing is enabled.

- `stencilTestEnable` controls whether stencil testing is enabled.

- `front` and `back` control the parameters of the stencil test.

- `minDepthBounds` and `maxDepthBounds` define the range of values used in the depth bounds test.

Valid Usage

- If the depth bounds testing feature is not enabled, `depthBoundsTestEnable` must be `VK_FALSE`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_DEPTH_STENCIL_STATE_CREATE_INFO`

- `pNext` must be `NULL`

- `flags` must be `0`

- `depthCompareOp` must be a valid VkCompareOp value

- `front` must be a valid VkStencilOpState structure

- `back` must be a valid VkStencilOpState structure

    typedef VkFlags VkPipelineDepthStencilStateCreateFlags;

`VkPipelineDepthStencilStateCreateFlags` is a bitmask type for setting a mask, but is currently reserved for future use.

### 27.11. Depth Bounds Test

The depth bounds test conditionally disables coverage of a sample based on the outcome of a comparison between the value za in the depth attachment at location (xf,yf) (for the appropriate sample) and a range of values. The test is enabled or disabled by the `depthBoundsTestEnable` member of VkPipelineDepthStencilStateCreateInfo: If the pipeline state object is created without the `VK_DYNAMIC_STATE_DEPTH_BOUNDS` dynamic state enabled then the range of values used in the depth bounds test are defined by the `minDepthBounds` and `maxDepthBounds` members of the VkPipelineDepthStencilStateCreateInfo structure. Otherwise, to dynamically set the depth bounds range values call:

    void vkCmdSetDepthBounds(
        VkCommandBuffer                             commandBuffer,
        float                                       minDepthBounds,
        float                                       maxDepthBounds);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `minDepthBounds` is the lower bound of the range of depth values used in the depth bounds test.

- `maxDepthBounds` is the upper bound of the range.

Valid Usage

- Unless the `VK_EXT_depth_range_unrestricted` extension is enabled `minDepthBounds` must be between `0.0` and `1.0`, inclusive

- Unless the `VK_EXT_depth_range_unrestricted` extension is enabled `maxDepthBounds` must be between `0.0` and `1.0`, inclusive

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics |

If `minDepthBounds` ≤ za ≤ `maxDepthBounds`, then the depth bounds test passes. Otherwise, the test fails and the sample’s coverage bit is cleared in the fragment. If there is no depth framebuffer attachment or if the depth bounds test is disabled, it is as if the depth bounds test always passes.

### 27.12. Stencil Test

The stencil test conditionally disables coverage of a sample based on the outcome of a comparison between the stencil value in the depth/stencil attachment at location (xf,yf) (for the appropriate sample) and a reference value. The stencil test also updates the value in the stencil attachment, depending on the test state, the stencil value and the stencil write masks. The stencil test is enabled or disabled by the `stencilTestEnable` member of VkPipelineDepthStencilStateCreateInfo.

When stencil test is disabled, the stencil test and associated modifications are not made, and the sample’s coverage is not modified.

The stencil test is controlled by the `front` and `back` members of `VkPipelineDepthStencilStateCreateInfo`, which are of type `VkStencilOpState`.

The `VkStencilOpState` structure is defined as:

    typedef struct VkStencilOpState {
        VkStencilOp    failOp;
        VkStencilOp    passOp;
        VkStencilOp    depthFailOp;
        VkCompareOp    compareOp;
        uint32_t       compareMask;
        uint32_t       writeMask;
        uint32_t       reference;
    } VkStencilOpState;

- `failOp` is a VkStencilOp value specifying the action performed on samples that fail the stencil test.

- `passOp` is a VkStencilOp value specifying the action performed on samples that pass both the depth and stencil tests.

- `depthFailOp` is a VkStencilOp value specifying the action performed on samples that pass the stencil test and fail the depth test.

- `compareOp` is a VkCompareOp value specifying the comparison operator used in the stencil test.

- `compareMask` selects the bits of the unsigned integer stencil values participating in the stencil test.

- `writeMask` selects the bits of the unsigned integer stencil values updated by the stencil test in the stencil framebuffer attachment.

- `reference` is an integer reference value that is used in the unsigned stencil comparison.

Valid Usage (Implicit)

- `failOp` must be a valid VkStencilOp value

- `passOp` must be a valid VkStencilOp value

- `depthFailOp` must be a valid VkStencilOp value

- `compareOp` must be a valid VkCompareOp value

There are two sets of stencil-related state, the front stencil state set and the back stencil state set. Stencil tests and writes use the front set of stencil state when processing front-facing fragments and use the back set of stencil state when processing back-facing fragments. Fragments rasterized from non-polygon primitives (points and lines) are always considered front-facing. Fragments rasterized from polygon primitives inherit their facingness from the polygon, even if the polygon is rasterized as points or lines due to the current VkPolygonMode. Whether a polygon is front- or back-facing is determined in the same manner used for face culling (see Basic Polygon Rasterization).

The operation of the stencil test is also affected by the `compareMask`, `writeMask`, and `reference` members of `VkStencilOpState` set in the pipeline state object if the pipeline state object is created without the `VK_DYNAMIC_STATE_STENCIL_COMPARE_MASK`, `VK_DYNAMIC_STATE_STENCIL_WRITE_MASK`, and `VK_DYNAMIC_STATE_STENCIL_REFERENCE` dynamic states enabled, respectively.

If the pipeline state object is created with the `VK_DYNAMIC_STATE_STENCIL_COMPARE_MASK` dynamic state enabled, then to dynamically set the stencil compare mask call:

    void vkCmdSetStencilCompareMask(
        VkCommandBuffer                             commandBuffer,
        VkStencilFaceFlags                          faceMask,
        uint32_t                                    compareMask);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `faceMask` is a bitmask of VkStencilFaceFlagBits specifying the set of stencil state for which to update the compare mask.

- `compareMask` is the new value to use as the stencil compare mask.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `faceMask` must be a valid combination of VkStencilFaceFlagBits values

- `faceMask` must not be `0`

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics |

Bits which can be set in the vkCmdSetStencilCompareMask::`faceMask` parameter, and similar parameters of other commands specifying which stencil state to update stencil masks for, are:

    typedef enum VkStencilFaceFlagBits {
        VK_STENCIL_FACE_FRONT_BIT = 0x00000001,
        VK_STENCIL_FACE_BACK_BIT = 0x00000002,
        VK_STENCIL_FACE_FRONT_AND_BACK = 0x00000003,
        VK_STENCIL_FRONT_AND_BACK = VK_STENCIL_FACE_FRONT_AND_BACK,
        VK_STENCIL_FACE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkStencilFaceFlagBits;

- `VK_STENCIL_FACE_FRONT_BIT` specifies that only the front set of stencil state is updated.

- `VK_STENCIL_FACE_BACK_BIT` specifies that only the back set of stencil state is updated.

- `VK_STENCIL_FACE_FRONT_AND_BACK` is the combination of `VK_STENCIL_FACE_FRONT_BIT` and `VK_STENCIL_FACE_BACK_BIT`, and specifies that both sets of stencil state are updated.

    typedef VkFlags VkStencilFaceFlags;

`VkStencilFaceFlags` is a bitmask type for setting a mask of zero or more VkStencilFaceFlagBits.

If the pipeline state object is created with the `VK_DYNAMIC_STATE_STENCIL_WRITE_MASK` dynamic state enabled, then to dynamically set the stencil write mask call:

    void vkCmdSetStencilWriteMask(
        VkCommandBuffer                             commandBuffer,
        VkStencilFaceFlags                          faceMask,
        uint32_t                                    writeMask);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `faceMask` is a bitmask of VkStencilFaceFlagBits specifying the set of stencil state for which to update the write mask, as described above for vkCmdSetStencilCompareMask.

- `writeMask` is the new value to use as the stencil write mask.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `faceMask` must be a valid combination of VkStencilFaceFlagBits values

- `faceMask` must not be `0`

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics |

If the pipeline state object is created with the `VK_DYNAMIC_STATE_STENCIL_REFERENCE` dynamic state enabled, then to dynamically set the stencil reference value call:

    void vkCmdSetStencilReference(
        VkCommandBuffer                             commandBuffer,
        VkStencilFaceFlags                          faceMask,
        uint32_t                                    reference);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `faceMask` is a bitmask of VkStencilFaceFlagBits specifying the set of stencil state for which to update the reference value, as described above for vkCmdSetStencilCompareMask.

- `reference` is the new value to use as the stencil reference value.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `faceMask` must be a valid combination of VkStencilFaceFlagBits values

- `faceMask` must not be `0`

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics |

`reference` is an integer reference value that is used in the unsigned stencil comparison. The reference value used by stencil comparison must be within the range [0,2s-1] , where s is the number of bits in the stencil framebuffer attachment, otherwise the reference value is considered undefined. The s least significant bits of `compareMask` are bitwise `ANDed` with both the reference and the stored stencil value, and the resulting masked values are those that participate in the comparison controlled by `compareOp`. Let R be the masked reference value and S be the masked stored stencil value.

Possible values of VkStencilOpState::`compareOp`, specifying the stencil comparison function, are:

    typedef enum VkCompareOp {
        VK_COMPARE_OP_NEVER = 0,
        VK_COMPARE_OP_LESS = 1,
        VK_COMPARE_OP_EQUAL = 2,
        VK_COMPARE_OP_LESS_OR_EQUAL = 3,
        VK_COMPARE_OP_GREATER = 4,
        VK_COMPARE_OP_NOT_EQUAL = 5,
        VK_COMPARE_OP_GREATER_OR_EQUAL = 6,
        VK_COMPARE_OP_ALWAYS = 7,
        VK_COMPARE_OP_MAX_ENUM = 0x7FFFFFFF
    } VkCompareOp;

- `VK_COMPARE_OP_NEVER` specifies that the test never passes.

- `VK_COMPARE_OP_LESS` specifies that the test passes when R < S.

- `VK_COMPARE_OP_EQUAL` specifies that the test passes when R = S.

- `VK_COMPARE_OP_LESS_OR_EQUAL` specifies that the test passes when R ≤ S.

- `VK_COMPARE_OP_GREATER` specifies that the test passes when R > S.

- `VK_COMPARE_OP_NOT_EQUAL` specifies that the test passes when R ≠ S.

- `VK_COMPARE_OP_GREATER_OR_EQUAL` specifies that the test passes when R ≥ S.

- `VK_COMPARE_OP_ALWAYS` specifies that the test always passes.

Possible values of the `failOp`, `passOp`, and `depthFailOp` members of VkStencilOpState, specifying what happens to the stored stencil value if this or certain subsequent tests fail or pass, are:

    typedef enum VkStencilOp {
        VK_STENCIL_OP_KEEP = 0,
        VK_STENCIL_OP_ZERO = 1,
        VK_STENCIL_OP_REPLACE = 2,
        VK_STENCIL_OP_INCREMENT_AND_CLAMP = 3,
        VK_STENCIL_OP_DECREMENT_AND_CLAMP = 4,
        VK_STENCIL_OP_INVERT = 5,
        VK_STENCIL_OP_INCREMENT_AND_WRAP = 6,
        VK_STENCIL_OP_DECREMENT_AND_WRAP = 7,
        VK_STENCIL_OP_MAX_ENUM = 0x7FFFFFFF
    } VkStencilOp;

- `VK_STENCIL_OP_KEEP` keeps the current value.

- `VK_STENCIL_OP_ZERO` sets the value to 0.

- `VK_STENCIL_OP_REPLACE` sets the value to `reference`.

- `VK_STENCIL_OP_INCREMENT_AND_CLAMP` increments the current value and clamps to the maximum representable unsigned value.

- `VK_STENCIL_OP_DECREMENT_AND_CLAMP` decrements the current value and clamps to 0.

- `VK_STENCIL_OP_INVERT` bitwise-inverts the current value.

- `VK_STENCIL_OP_INCREMENT_AND_WRAP` increments the current value and wraps to 0 when the maximum value would have been exceeded.

- `VK_STENCIL_OP_DECREMENT_AND_WRAP` decrements the current value and wraps to the maximum possible value when the value would go below 0.

For purposes of increment and decrement, the stencil bits are considered as an unsigned integer.

If the stencil test fails, the sample’s coverage bit is cleared in the fragment. If there is no stencil framebuffer attachment, stencil modification cannot occur, and it is as if the stencil tests always pass.

If the stencil test passes, the `writeMask` member of the VkStencilOpState structures controls how the updated stencil value is written to the stencil framebuffer attachment.

The least significant s bits of `writeMask`, where s is the number of bits in the stencil framebuffer attachment, specify an integer mask. Where a 1 appears in this mask, the corresponding bit in the stencil value in the depth/stencil attachment is written; where a 0 appears, the bit is not written. The `writeMask` value uses either the front-facing or back-facing state based on the facingness of the fragment. Fragments generated by front-facing primitives use the front mask and fragments generated by back-facing primitives use the back mask.

### 27.13. Depth Test

The depth test conditionally disables coverage of a sample based on the outcome of a comparison between the fragment’s depth value at the sample location and the sample’s depth value in the depth/stencil attachment at location (xf,yf). The comparison is enabled or disabled with the `depthTestEnable` member of the VkPipelineDepthStencilStateCreateInfo structure. When disabled, the depth comparison and subsequent possible updates to the value of the depth component of the depth/stencil attachment are bypassed and the fragment is passed to the next operation. The stencil value, however, can be modified as indicated above as if the depth test passed. If enabled, the comparison takes place and the depth/stencil attachment value can subsequently be modified.

The comparison is specified with the `depthCompareOp` member of VkPipelineDepthStencilStateCreateInfo. Let `z`f be the incoming fragment’s depth value for a sample, and let za be the depth/stencil attachment value in memory for that sample. The depth test passes under the following conditions:

- `VK_COMPARE_OP_NEVER`: the test never passes.

- `VK_COMPARE_OP_LESS`: the test passes when zf < za.

- `VK_COMPARE_OP_EQUAL`: the test passes when zf = za.

- `VK_COMPARE_OP_LESS_OR_EQUAL`: the test passes when zf ≤ za.

- `VK_COMPARE_OP_GREATER`: the test passes when zf > za.

- `VK_COMPARE_OP_NOT_EQUAL`: the test passes when zf ≠ za.

- `VK_COMPARE_OP_GREATER_OR_EQUAL`: the test passes when zf ≥ za.

- `VK_COMPARE_OP_ALWAYS`: the test always passes.

If VkPipelineRasterizationStateCreateInfo::`depthClampEnable` is enabled, before the incoming fragment’s `z`f is compared to `z`a, `z`f is clamped to [min(n,f),max(n,f)], where n and f are the `minDepth` and `maxDepth` depth range values of the viewport used by this fragment, respectively.

If the depth test fails, the sample’s coverage bit is cleared in the fragment. The stencil value at the sample’s location is updated according to the function currently in effect for depth test failure.

If the depth test passes, the sample’s (possibly clamped) `z`f value is conditionally written to the depth framebuffer attachment based on the `depthWriteEnable` member of VkPipelineDepthStencilStateCreateInfo. The value is written if `depthWriteEnable` is `VK_TRUE` and there is a depth framebuffer attachment. Otherwise, no value is written. If the depth framebuffer attachment is a fixed-point format and the depth value is outside of the `0.0` to `1.0` range the depth value is clamped between `0.0` and `1.0` inclusive before writing. The stencil value at the sample’s location is updated according to the function currently in effect for depth test success.

If there is no depth framebuffer attachment, it is as if the depth test always passes.

### 27.14. Representative Fragment Test

The representative fragment test allows implementations to reduce the amount of rasterization and fragment processing work performed for each point, line, or triangle primitive. For any primitive that produces one or more fragments that pass all prior early fragment tests, the implementation may choose one or more “representative” fragments for processing and discard all other fragments. For draw calls rendering multiple points, lines, or triangles arranged in lists, strips, or fans, the representative fragment test is performed independently for each of those primitives. The set of fragments discarded by the representative fragment test is implementation-dependent. In some cases, the representative fragment test may not discard any fragments for a given primitive.

If the `pNext` chain of VkGraphicsPipelineCreateInfo includes a `VkPipelineRepresentativeFragmentTestStateCreateInfoNV` structure, then that structure includes parameters that control the representative fragment test.

The `VkPipelineRepresentativeFragmentTestStateCreateInfoNV` structure is defined as:

    typedef struct VkPipelineRepresentativeFragmentTestStateCreateInfoNV {
        VkStructureType    sType;
        const void*        pNext;
        VkBool32           representativeFragmentTestEnable;
    } VkPipelineRepresentativeFragmentTestStateCreateInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `representativeFragmentTestEnable` controls whether the representative fragment test is enabled.

If this structure is not present, `representativeFragmentTestEnable` is considered to be `VK_FALSE`, and the representative fragment test is disabled.

If early fragment tests are not enabled in the active fragment shader, the representative fragment shader test has no effect, even if enabled.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_REPRESENTATIVE_FRAGMENT_TEST_STATE_CREATE_INFO_NV`

### 27.15. Sample Counting

Occlusion queries use query pool entries to track the number of samples that pass all the per-fragment tests. The mechanism of collecting an occlusion query value is described in Occlusion Queries.

The occlusion query sample counter increments by one for each sample with a coverage value of 1 in each fragment that survives all the per-fragment tests, including scissor, exclusive scissor, sample mask, alpha to coverage, stencil, and depth tests.

### 27.16. Fragment Coverage To Color

If the `pNext` chain of VkPipelineMultisampleStateCreateInfo includes a `VkPipelineCoverageToColorStateCreateInfoNV` structure, then that structure controls whether the fragment coverage is substituted for a fragment color output and, if so, which output is replaced.

The `VkPipelineCoverageToColorStateCreateInfoNV` structure is defined as:

    typedef struct VkPipelineCoverageToColorStateCreateInfoNV {
        VkStructureType                                sType;
        const void*                                    pNext;
        VkPipelineCoverageToColorStateCreateFlagsNV    flags;
        VkBool32                                       coverageToColorEnable;
        uint32_t                                       coverageToColorLocation;
    } VkPipelineCoverageToColorStateCreateInfoNV;

- `sType` is the type of this structure

- `pNext` is `NULL` or a pointer to an extension-specific structure

- `flags` is reserved for future use.

- `coverageToColorEnable` controls whether the fragment coverage value replaces a fragment color output.

- `coverageToColorLocation` controls which fragment shader color output value is replaced.

If `coverageToColorEnable` is `VK_TRUE`, the fragment coverage information is treated as a bitmask with one bit for each sample (as in the Sample Mask section), and this bitmask replaces the first component of the color value corresponding to the fragment shader output location with `Location` equal to `coverageToColorLocation` and `Index` equal to zero. If the color attachment format has fewer bits than the sample coverage, the low bits of the sample coverage bitmask are taken without any clamping. If the color attachment format has more bits than the sample coverage, the high bits of the sample coverage bitmask are filled with zeros.

If Sample Shading is in use, the coverage bitmask only has bits set for samples that correspond to the fragment shader invocation that shades those samples.

This pipeline stage occurs after sample counting and before blending, and is always performed after fragment shading regardless of the setting of `EarlyFragmentTests`.

If `coverageToColorEnable` is `VK_FALSE`, these operations are skipped. If this structure is not present, it is as if `coverageToColorEnable` is `VK_FALSE`.

Valid Usage

- If `coverageToColorEnable` is `VK_TRUE`, then the render pass subpass indicated by VkGraphicsPipelineCreateInfo::`renderPass` and VkGraphicsPipelineCreateInfo::`subpass` must have a color attachment at the location selected by `coverageToColorLocation`, with a VkFormat of `VK_FORMAT_R8_UINT`, `VK_FORMAT_R8_SINT`, `VK_FORMAT_R16_UINT`, `VK_FORMAT_R16_SINT`, `VK_FORMAT_R32_UINT`, or `VK_FORMAT_R32_SINT`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_COVERAGE_TO_COLOR_STATE_CREATE_INFO_NV`

- `flags` must be `0`

    typedef VkFlags VkPipelineCoverageToColorStateCreateFlagsNV;

`VkPipelineCoverageToColorStateCreateFlagsNV` is a bitmask type for setting a mask, but is currently reserved for future use.

### 27.17. Coverage Reduction

Coverage reduction generates a color sample mask from the coverage mask, with one bit for each sample in the color attachment(s) for the subpass. If a bit in the color sample mask is 0, then blending and writing to the framebuffer are not performed for that sample.

When the `VK_NV_framebuffer_mixed_samples` extension is not enabled, each color sample is associated with a unique rasterization sample, and the value of the coverage mask is assigned to the color sample mask.

If the render pass has a fragment density map attachment, `rasterizationSamples` is greater than 1, and the fragment area covers multiple pixels; there is an implementation-dependent association of rasterization samples to color attachment samples within the fragment. Each color sample’s mask bit is assigned the union of the coverage bits of its associated raster samples.

If the pipeline’s VkPipelineMultisampleStateCreateInfo::`rasterizationSamples` is greater than the VkAttachmentDescription::`samples` of the color attachments in the subpass, then the fragment’s coverage is reduced from `rasterizationSamples` bits to a color sample mask with VkAttachmentDescription::`samples` bits.

When the `VK_NV_coverage_reduction_mode` extension is enabled, the pipeline state controlling coverage reduction is specified through the members of the `VkPipelineCoverageReductionStateCreateInfoNV` structure.

The `VkPipelineCoverageReductionStateCreateInfoNV` structure is defined as:

    typedef struct VkPipelineCoverageReductionStateCreateInfoNV {
        VkStructureType                                  sType;
        const void*                                      pNext;
        VkPipelineCoverageReductionStateCreateFlagsNV    flags;
        VkCoverageReductionModeNV                        coverageReductionMode;
    } VkPipelineCoverageReductionStateCreateInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `coverageReductionMode` is a VkCoverageReductionModeNV value controlling how the color sample mask is generated from the coverage mask.

If this structure is not present, the default coverage reduction mode is inferred as follows:

- If the `VK_NV_framebuffer_mixed_samples` extension is enabled, then it is as if the `coverageReductionMode` is `VK_COVERAGE_REDUCTION_MODE_MERGE_NV`.

- If the `VK_AMD_mixed_attachment_samples` extension is enabled, then it is as if the `coverageReductionMode` is `VK_COVERAGE_REDUCTION_MODE_TRUNCATE_NV`.

- If both `VK_NV_framebuffer_mixed_samples` and `VK_AMD_mixed_attachment_samples` are enabled, then the default coverage reduction mode is implementation-dependent.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_COVERAGE_REDUCTION_STATE_CREATE_INFO_NV`

- `flags` must be `0`

- `coverageReductionMode` must be a valid VkCoverageReductionModeNV value

    typedef VkFlags VkPipelineCoverageReductionStateCreateFlagsNV;

`VkPipelineCoverageReductionStateCreateFlagsNV` is a bitmask type for setting a mask, but is currently reserved for future use.

Possible values of VkPipelineCoverageReductionStateCreateInfoNV::`coverageReductionMode`, specifying how the coverage mask is reduced to color sample mask, are:

    typedef enum VkCoverageReductionModeNV {
        VK_COVERAGE_REDUCTION_MODE_MERGE_NV = 0,
        VK_COVERAGE_REDUCTION_MODE_TRUNCATE_NV = 1,
        VK_COVERAGE_REDUCTION_MODE_MAX_ENUM_NV = 0x7FFFFFFF
    } VkCoverageReductionModeNV;

- `VK_COVERAGE_REDUCTION_MODE_MERGE_NV`: In this mode, there is an implementation-dependent association of each raster sample to a color sample. The reduced color sample mask is computed such that the bit for each color sample is 1 if any of the associated bits in the fragment’s coverage is on, and 0 otherwise.

- `VK_COVERAGE_REDUCTION_MODE_TRUNCATE_NV`: In this mode, only the first M raster samples are associated with the color samples such that raster sample i maps to color sample i, where M is the number of color samples.

If the `VK_NV_coverage_reduction_mode` extension is not enabled, there is an implementation-dependent association of raster samples to color samples. The reduced color sample mask is computed such that the bit for each color sample is 1 if any of the associated bits in the fragment’s coverage is on, and 0 otherwise.

To query the set of mixed sample combinations of coverage reduction mode, rasterization samples and color, depth, stencil attachment sample counts that are supported by a physical device, call:

    VkResult vkGetPhysicalDeviceSupportedFramebufferMixedSamplesCombinationsNV(
        VkPhysicalDevice                            physicalDevice,
        uint32_t*                                   pCombinationCount,
        VkFramebufferMixedSamplesCombinationNV*     pCombinations);

- `physicalDevice` is the physical device from which to query the set of combinations.

- `pCombinationCount` is a pointer to an integer related to the number of combinations available or queried, as described below.

- `pCombinations` is either `NULL` or a pointer to an array of VkFramebufferMixedSamplesCombinationNV values, indicating the supported combinations of coverage reduction mode, rasterization samples, and color, depth, stencil attachment sample counts.

If `pCombinations` is `NULL`, then the number of supported combinations for the given `physicalDevice` is returned in `pCombinationCount`. Otherwise, `pCombinationCount` must point to a variable set by the user to the number of elements in the `pCombinations` array, and on return the variable is overwritten with the number of values actually written to `pCombinations`. If the value of `pCombinationCount` is less than the number of combinations supported for the given `physicalDevice`, at most `pCombinationCount` values will be written `pCombinations` and `VK_INCOMPLETE` will be returned instead of `VK_SUCCESS` to indicate that not all the supported values were returned.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pCombinationCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pCombinationCount` is not `0`, and `pCombinations` is not `NULL`, `pCombinations` must be a valid pointer to an array of `pCombinationCount` VkFramebufferMixedSamplesCombinationNV structures

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkFramebufferMixedSamplesCombinationNV` structure is defined as:

    typedef struct VkFramebufferMixedSamplesCombinationNV {
        VkStructureType              sType;
        void*                        pNext;
        VkCoverageReductionModeNV    coverageReductionMode;
        VkSampleCountFlagBits        rasterizationSamples;
        VkSampleCountFlags           depthStencilSamples;
        VkSampleCountFlags           colorSamples;
    } VkFramebufferMixedSamplesCombinationNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `coverageReductionMode` is a VkCoverageReductionModeNV value specifying the coverage reduction mode.

- `rasterizationSamples` specifies the number of rasterization samples in the supported combination.

- `depthStencilSamples` specifies the number of samples in the depth stencil attachment in the supported combination. A value of 0 indicates the combination does not have a depth stencil attachment.

- `colorSamples` specifies the number of color samples in a color attachment in the supported combination. A value of 0 indicates the combination does not have a color attachment.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_FRAMEBUFFER_MIXED_SAMPLES_COMBINATION_NV`

- `pNext` must be `NULL`

#### 27.17.1. Coverage Modulation

As part of coverage reduction, fragment color values can also be modulated (multiplied) by a value that is a function of fraction of covered rasterization samples associated with that color sample.

Pipeline state controlling coverage modulation is specified through the members of the `VkPipelineCoverageModulationStateCreateInfoNV` structure.

The `VkPipelineCoverageModulationStateCreateInfoNV` structure is defined as:

    typedef struct VkPipelineCoverageModulationStateCreateInfoNV {
        VkStructureType                                   sType;
        const void*                                       pNext;
        VkPipelineCoverageModulationStateCreateFlagsNV    flags;
        VkCoverageModulationModeNV                        coverageModulationMode;
        VkBool32                                          coverageModulationTableEnable;
        uint32_t                                          coverageModulationTableCount;
        const float*                                      pCoverageModulationTable;
    } VkPipelineCoverageModulationStateCreateInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `coverageModulationMode` is a VkCoverageModulationModeNV value controlling which color components are modulated.

- `coverageModulationTableEnable` controls whether the modulation factor is looked up from a table in `pCoverageModulationTable`.

- `coverageModulationTableCount` is the number of elements in `pCoverageModulationTable`.

- `pCoverageModulationTable` is a table of modulation factors containing a value for each number of covered samples.

If `coverageModulationTableEnable` is `VK_FALSE`, then for each color sample the associated bits of the fragment’s coverage are counted and divided by the number of associated bits to produce a modulation factor R in the range (0,1] (a value of zero would have been killed due to a color coverage of 0). Specifically:

- N = value of `rasterizationSamples`

- M = value of VkAttachmentDescription::`samples` for any color attachments

- R = popcount(associated coverage bits) / (N / M)

If `coverageModulationTableEnable` is `VK_TRUE`, the value R is computed using a programmable lookup table. The lookup table has N / M elements, and the element of the table is selected by:

- R = `pCoverageModulationTable`[popcount(associated coverage bits)-1]

Note that the table does not have an entry for popcount(associated coverage bits) = 0, because such samples would have been killed.

The values of `pCoverageModulationTable` may be rounded to an implementation-dependent precision, which is at least as fine as 1 / N, and clamped to [0,1].

For each color attachment with a floating point or normalized color format, each fragment output color value is replicated to M values which can each be modulated (multiplied) by that color sample’s associated value of R. Which components are modulated is controlled by `coverageModulationMode`.

If this structure is not present, it is as if `coverageModulationMode` is `VK_COVERAGE_MODULATION_MODE_NONE_NV`.

If the coverage reduction mode is `VK_COVERAGE_REDUCTION_MODE_TRUNCATE_NV`, each color sample is associated with only a single coverage sample. In this case, it is as if `coverageModulationMode` is `VK_COVERAGE_MODULATION_MODE_NONE_NV`.

Valid Usage

- If `coverageModulationTableEnable` is `VK_TRUE`, `coverageModulationTableCount` must be equal to the number of rasterization samples divided by the number of color samples in the subpass

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_COVERAGE_MODULATION_STATE_CREATE_INFO_NV`

- `flags` must be `0`

- `coverageModulationMode` must be a valid VkCoverageModulationModeNV value

    typedef VkFlags VkPipelineCoverageModulationStateCreateFlagsNV;

`VkPipelineCoverageModulationStateCreateFlagsNV` is a bitmask type for setting a mask, but is currently reserved for future use.

Possible values of VkPipelineCoverageModulationStateCreateInfoNV::`coverageModulationMode`, specifying which color components are modulated, are:

    typedef enum VkCoverageModulationModeNV {
        VK_COVERAGE_MODULATION_MODE_NONE_NV = 0,
        VK_COVERAGE_MODULATION_MODE_RGB_NV = 1,
        VK_COVERAGE_MODULATION_MODE_ALPHA_NV = 2,
        VK_COVERAGE_MODULATION_MODE_RGBA_NV = 3,
        VK_COVERAGE_MODULATION_MODE_MAX_ENUM_NV = 0x7FFFFFFF
    } VkCoverageModulationModeNV;

- `VK_COVERAGE_MODULATION_MODE_NONE_NV` specifies that no components are multiplied by the modulation factor.

- `VK_COVERAGE_MODULATION_MODE_RGB_NV` specifies that the red, green, and blue components are multiplied by the modulation factor.

- `VK_COVERAGE_MODULATION_MODE_ALPHA_NV` specifies that the alpha component is multiplied by the modulation factor.

- `VK_COVERAGE_MODULATION_MODE_RGBA_NV` specifies that all components are multiplied by the modulation factor.

## 28. The Framebuffer

### 28.1. Blending

Blending combines the incoming source fragment’s R, G, B, and A values with the destination R, G, B, and A values of each sample stored in the framebuffer at the fragment’s (xf,yf) location. Blending is performed for each color sample covered by the fragment, rather than just once for each fragment.

Source and destination values are combined according to the blend operation, quadruplets of source and destination weighting factors determined by the blend factors, and a blend constant, to obtain a new set of R, G, B, and A values, as described below.

Blending is computed and applied separately to each color attachment used by the subpass, with separate controls for each attachment.

Prior to performing the blend operation, signed and unsigned normalized fixed-point color components undergo an implied conversion to floating-point as specified by Conversion from Normalized Fixed-Point to Floating-Point. Blending computations are treated as if carried out in floating-point, and basic blend operations are performed with a precision and dynamic range no lower than that used to represent destination components. Advanced blending operations are performed with a precision and dynamic range no lower than the smaller of that used to represent destination components or that used to represent 16-bit floating-point values.

Blending applies only to fixed-point and floating-point color attachments. If the color attachment has an integer format, blending is not applied.

The pipeline blend state is included in the `VkPipelineColorBlendStateCreateInfo` structure during graphics pipeline creation:

The `VkPipelineColorBlendStateCreateInfo` structure is defined as:

    typedef struct VkPipelineColorBlendStateCreateInfo {
        VkStructureType                               sType;
        const void*                                   pNext;
        VkPipelineColorBlendStateCreateFlags          flags;
        VkBool32                                      logicOpEnable;
        VkLogicOp                                     logicOp;
        uint32_t                                      attachmentCount;
        const VkPipelineColorBlendAttachmentState*    pAttachments;
        float                                         blendConstants[4];
    } VkPipelineColorBlendStateCreateInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `logicOpEnable` controls whether to apply Logical Operations.

- `logicOp` selects which logical operation to apply.

- `attachmentCount` is the number of `VkPipelineColorBlendAttachmentState` elements in `pAttachments`. This value must equal the `colorAttachmentCount` for the subpass in which this pipeline is used.

- `pAttachments`: is a pointer to an array of per target attachment states.

- `blendConstants` is a pointer to an array of four values used as the R, G, B, and A components of the blend constant that are used in blending, depending on the blend factor.

Each element of the `pAttachments` array is a VkPipelineColorBlendAttachmentState structure specifying per-target blending state for each individual color attachment. If the independent blending feature is not enabled on the device, all VkPipelineColorBlendAttachmentState elements in the `pAttachments` array must be identical.

Valid Usage

- If the independent blending feature is not enabled, all elements of `pAttachments` must be identical

- If the logic operations feature is not enabled, `logicOpEnable` must be `VK_FALSE`

- If `logicOpEnable` is `VK_TRUE`, `logicOp` must be a valid VkLogicOp value

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_STATE_CREATE_INFO`

- `pNext` must be `NULL` or a pointer to a valid instance of VkPipelineColorBlendAdvancedStateCreateInfoEXT

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be `0`

- If `attachmentCount` is not `0`, `pAttachments` must be a valid pointer to an array of `attachmentCount` valid VkPipelineColorBlendAttachmentState structures

    typedef VkFlags VkPipelineColorBlendStateCreateFlags;

`VkPipelineColorBlendStateCreateFlags` is a bitmask type for setting a mask, but is currently reserved for future use.

The `VkPipelineColorBlendAttachmentState` structure is defined as:

    typedef struct VkPipelineColorBlendAttachmentState {
        VkBool32                 blendEnable;
        VkBlendFactor            srcColorBlendFactor;
        VkBlendFactor            dstColorBlendFactor;
        VkBlendOp                colorBlendOp;
        VkBlendFactor            srcAlphaBlendFactor;
        VkBlendFactor            dstAlphaBlendFactor;
        VkBlendOp                alphaBlendOp;
        VkColorComponentFlags    colorWriteMask;
    } VkPipelineColorBlendAttachmentState;

- `blendEnable` controls whether blending is enabled for the corresponding color attachment. If blending is not enabled, the source fragment’s color for that attachment is passed through unmodified.

- `srcColorBlendFactor` selects which blend factor is used to determine the source factors (Sr,Sg,Sb).

- `dstColorBlendFactor` selects which blend factor is used to determine the destination factors (Dr,Dg,Db).

- `colorBlendOp` selects which blend operation is used to calculate the RGB values to write to the color attachment.

- `srcAlphaBlendFactor` selects which blend factor is used to determine the source factor Sa.

- `dstAlphaBlendFactor` selects which blend factor is used to determine the destination factor Da.

- `alphaBlendOp` selects which blend operation is use to calculate the alpha values to write to the color attachment.

- `colorWriteMask` is a bitmask of VkColorComponentFlagBits specifying which of the R, G, B, and/or A components are enabled for writing, as described for the Color Write Mask.

Valid Usage

- If the dual source blending feature is not enabled, `srcColorBlendFactor` must not be `VK_BLEND_FACTOR_SRC1_COLOR`, `VK_BLEND_FACTOR_ONE_MINUS_SRC1_COLOR`, `VK_BLEND_FACTOR_SRC1_ALPHA`, or `VK_BLEND_FACTOR_ONE_MINUS_SRC1_ALPHA`

- If the dual source blending feature is not enabled, `dstColorBlendFactor` must not be `VK_BLEND_FACTOR_SRC1_COLOR`, `VK_BLEND_FACTOR_ONE_MINUS_SRC1_COLOR`, `VK_BLEND_FACTOR_SRC1_ALPHA`, or `VK_BLEND_FACTOR_ONE_MINUS_SRC1_ALPHA`

- If the dual source blending feature is not enabled, `srcAlphaBlendFactor` must not be `VK_BLEND_FACTOR_SRC1_COLOR`, `VK_BLEND_FACTOR_ONE_MINUS_SRC1_COLOR`, `VK_BLEND_FACTOR_SRC1_ALPHA`, or `VK_BLEND_FACTOR_ONE_MINUS_SRC1_ALPHA`

- If the dual source blending feature is not enabled, `dstAlphaBlendFactor` must not be `VK_BLEND_FACTOR_SRC1_COLOR`, `VK_BLEND_FACTOR_ONE_MINUS_SRC1_COLOR`, `VK_BLEND_FACTOR_SRC1_ALPHA`, or `VK_BLEND_FACTOR_ONE_MINUS_SRC1_ALPHA`

- If either of `colorBlendOp` or `alphaBlendOp` is an advanced blend operation, then `colorBlendOp` must equal `alphaBlendOp`

- If VkPhysicalDeviceBlendOperationAdvancedPropertiesEXT::`advancedBlendIndependentBlend` is `VK_FALSE` and `colorBlendOp` is an advanced blend operation, then `colorBlendOp` must be the same for all attachments.

- If VkPhysicalDeviceBlendOperationAdvancedPropertiesEXT::`advancedBlendIndependentBlend` is `VK_FALSE` and `alphaBlendOp` is an advanced blend operation, then `alphaBlendOp` must be the same for all attachments.

- If VkPhysicalDeviceBlendOperationAdvancedPropertiesEXT::`advancedBlendAllOperations` is `VK_FALSE`, then `colorBlendOp` must not be `VK_BLEND_OP_ZERO_EXT`, `VK_BLEND_OP_SRC_EXT`, `VK_BLEND_OP_DST_EXT`, `VK_BLEND_OP_SRC_OVER_EXT`, `VK_BLEND_OP_DST_OVER_EXT`, `VK_BLEND_OP_SRC_IN_EXT`, `VK_BLEND_OP_DST_IN_EXT`, `VK_BLEND_OP_SRC_OUT_EXT`, `VK_BLEND_OP_DST_OUT_EXT`, `VK_BLEND_OP_SRC_ATOP_EXT`, `VK_BLEND_OP_DST_ATOP_EXT`, `VK_BLEND_OP_XOR_EXT`, `VK_BLEND_OP_INVERT_EXT`, `VK_BLEND_OP_INVERT_RGB_EXT`, `VK_BLEND_OP_LINEARDODGE_EXT`, `VK_BLEND_OP_LINEARBURN_EXT`, `VK_BLEND_OP_VIVIDLIGHT_EXT`, `VK_BLEND_OP_LINEARLIGHT_EXT`, `VK_BLEND_OP_PINLIGHT_EXT`, `VK_BLEND_OP_HARDMIX_EXT`, `VK_BLEND_OP_PLUS_EXT`, `VK_BLEND_OP_PLUS_CLAMPED_EXT`, `VK_BLEND_OP_PLUS_CLAMPED_ALPHA_EXT`, `VK_BLEND_OP_PLUS_DARKER_EXT`, `VK_BLEND_OP_MINUS_EXT`, `VK_BLEND_OP_MINUS_CLAMPED_EXT`, `VK_BLEND_OP_CONTRAST_EXT`, `VK_BLEND_OP_INVERT_OVG_EXT`, `VK_BLEND_OP_RED_EXT`, `VK_BLEND_OP_GREEN_EXT`, or `VK_BLEND_OP_BLUE_EXT`

- If `colorBlendOp` or `alphaBlendOp` is an advanced blend operation, then VkSubpassDescription::`colorAttachmentCount` of the subpass this pipeline is compiled against must be less than or equal to VkPhysicalDeviceBlendOperationAdvancedPropertiesEXT::advancedBlendMaxColorAttachments

Valid Usage (Implicit)

- `srcColorBlendFactor` must be a valid VkBlendFactor value

- `dstColorBlendFactor` must be a valid VkBlendFactor value

- `colorBlendOp` must be a valid VkBlendOp value

- `srcAlphaBlendFactor` must be a valid VkBlendFactor value

- `dstAlphaBlendFactor` must be a valid VkBlendFactor value

- `alphaBlendOp` must be a valid VkBlendOp value

- `colorWriteMask` must be a valid combination of VkColorComponentFlagBits values

#### 28.1.1. Blend Factors

The source and destination color and alpha blending factors are selected from the enum:

    typedef enum VkBlendFactor {
        VK_BLEND_FACTOR_ZERO = 0,
        VK_BLEND_FACTOR_ONE = 1,
        VK_BLEND_FACTOR_SRC_COLOR = 2,
        VK_BLEND_FACTOR_ONE_MINUS_SRC_COLOR = 3,
        VK_BLEND_FACTOR_DST_COLOR = 4,
        VK_BLEND_FACTOR_ONE_MINUS_DST_COLOR = 5,
        VK_BLEND_FACTOR_SRC_ALPHA = 6,
        VK_BLEND_FACTOR_ONE_MINUS_SRC_ALPHA = 7,
        VK_BLEND_FACTOR_DST_ALPHA = 8,
        VK_BLEND_FACTOR_ONE_MINUS_DST_ALPHA = 9,
        VK_BLEND_FACTOR_CONSTANT_COLOR = 10,
        VK_BLEND_FACTOR_ONE_MINUS_CONSTANT_COLOR = 11,
        VK_BLEND_FACTOR_CONSTANT_ALPHA = 12,
        VK_BLEND_FACTOR_ONE_MINUS_CONSTANT_ALPHA = 13,
        VK_BLEND_FACTOR_SRC_ALPHA_SATURATE = 14,
        VK_BLEND_FACTOR_SRC1_COLOR = 15,
        VK_BLEND_FACTOR_ONE_MINUS_SRC1_COLOR = 16,
        VK_BLEND_FACTOR_SRC1_ALPHA = 17,
        VK_BLEND_FACTOR_ONE_MINUS_SRC1_ALPHA = 18,
        VK_BLEND_FACTOR_MAX_ENUM = 0x7FFFFFFF
    } VkBlendFactor;

The semantics of each enum value is described in the table below:

Table 32. Blend Factors
VkBlendFactor | RGB Blend Factors (Sr,Sg,Sb) or (Dr,Dg,Db) | Alpha Blend Factor (Sa or Da)
--- | --- | ---
`VK_BLEND_FACTOR_ZERO` | (0,0,0) | 0
`VK_BLEND_FACTOR_ONE` | (1,1,1) | 1
`VK_BLEND_FACTOR_SRC_COLOR` | (Rs0,Gs0,Bs0) | As0
`VK_BLEND_FACTOR_ONE_MINUS_SRC_COLOR` | (1-Rs0,1-Gs0,1-Bs0) | 1-As0
`VK_BLEND_FACTOR_DST_COLOR` | (Rd,Gd,Bd) | Ad
`VK_BLEND_FACTOR_ONE_MINUS_DST_COLOR` | (1-Rd,1-Gd,1-Bd) | 1-Ad
`VK_BLEND_FACTOR_SRC_ALPHA` | (As0,As0,As0) | As0
`VK_BLEND_FACTOR_ONE_MINUS_SRC_ALPHA` | (1-As0,1-As0,1-As0) | 1-As0
`VK_BLEND_FACTOR_DST_ALPHA` | (Ad,Ad,Ad) | Ad
`VK_BLEND_FACTOR_ONE_MINUS_DST_ALPHA` | (1-Ad,1-Ad,1-Ad) | 1-Ad
`VK_BLEND_FACTOR_CONSTANT_COLOR` | (Rc,Gc,Bc) | Ac
`VK_BLEND_FACTOR_ONE_MINUS_CONSTANT_COLOR` | (1-Rc,1-Gc,1-Bc) | 1-Ac
`VK_BLEND_FACTOR_CONSTANT_ALPHA` | (Ac,Ac,Ac) | Ac
`VK_BLEND_FACTOR_ONE_MINUS_CONSTANT_ALPHA` | (1-Ac,1-Ac,1-Ac) | 1-Ac
`VK_BLEND_FACTOR_SRC_ALPHA_SATURATE` | (f,f,f); f = min(As0,1-Ad) | 1
`VK_BLEND_FACTOR_SRC1_COLOR` | (Rs1,Gs1,Bs1) | As1
`VK_BLEND_FACTOR_ONE_MINUS_SRC1_COLOR` | (1-Rs1,1-Gs1,1-Bs1) | 1-As1
`VK_BLEND_FACTOR_SRC1_ALPHA` | (As1,As1,As1) | As1
`VK_BLEND_FACTOR_ONE_MINUS_SRC1_ALPHA` | (1-As1,1-As1,1-As1) | 1-As1

In this table, the following conventions are used:

- Rs0,Gs0,Bs0 and As0 represent the first source color R, G, B, and A components, respectively, for the fragment output location corresponding to the color attachment being blended.

- Rs1,Gs1,Bs1 and As1 represent the second source color R, G, B, and A components, respectively, used in dual source blending modes, for the fragment output location corresponding to the color attachment being blended.

- Rd,Gd,Bd and Ad represent the R, G, B, and A components of the destination color. That is, the color currently in the corresponding color attachment for this fragment/sample.

- Rc,Gc,Bc and Ac represent the blend constant R, G, B, and A components, respectively.

If the pipeline state object is created without the `VK_DYNAMIC_STATE_BLEND_CONSTANTS` dynamic state enabled then the blend constant (Rc,Gc,Bc,Ac) is specified via the `blendConstants` member of VkPipelineColorBlendStateCreateInfo.

Otherwise, to dynamically set and change the blend constant, call:

    void vkCmdSetBlendConstants(
        VkCommandBuffer                             commandBuffer,
        const float                                 blendConstants[4]);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `blendConstants` is a pointer to an array of four values specifying the R, G, B, and A components of the blend constant color used in blending, depending on the blend factor.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics operations

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics |

#### 28.1.2. Dual-Source Blending

Blend factors that use the secondary color input (Rs1,Gs1,Bs1,As1) (`VK_BLEND_FACTOR_SRC1_COLOR`, `VK_BLEND_FACTOR_ONE_MINUS_SRC1_COLOR`, `VK_BLEND_FACTOR_SRC1_ALPHA`, and `VK_BLEND_FACTOR_ONE_MINUS_SRC1_ALPHA`) may consume implementation resources that could otherwise be used for rendering to multiple color attachments. Therefore, the number of color attachments that can be used in a framebuffer may be lower when using dual-source blending.

Dual-source blending is only supported if the `dualSrcBlend` feature is enabled.

The maximum number of color attachments that can be used in a subpass when using dual-source blending functions is implementation-dependent and is reported as the `maxFragmentDualSrcAttachments` member of `VkPhysicalDeviceLimits`.

When using a fragment shader with dual-source blending functions, the color outputs are bound to the first and second inputs of the blender using the `Index` decoration, as described in Fragment Output Interface. If the second color input to the blender is not written in the shader, or if no output is bound to the second input of a blender, the result of the blending operation is not defined.

#### 28.1.3. Blend Operations

Once the source and destination blend factors have been selected, they along with the source and destination components are passed to the blending operations. RGB and alpha components can use different operations. Possible values of VkBlendOp, specifying the operations, are:

    typedef enum VkBlendOp {
        VK_BLEND_OP_ADD = 0,
        VK_BLEND_OP_SUBTRACT = 1,
        VK_BLEND_OP_REVERSE_SUBTRACT = 2,
        VK_BLEND_OP_MIN = 3,
        VK_BLEND_OP_MAX = 4,
        VK_BLEND_OP_ZERO_EXT = 1000148000,
        VK_BLEND_OP_SRC_EXT = 1000148001,
        VK_BLEND_OP_DST_EXT = 1000148002,
        VK_BLEND_OP_SRC_OVER_EXT = 1000148003,
        VK_BLEND_OP_DST_OVER_EXT = 1000148004,
        VK_BLEND_OP_SRC_IN_EXT = 1000148005,
        VK_BLEND_OP_DST_IN_EXT = 1000148006,
        VK_BLEND_OP_SRC_OUT_EXT = 1000148007,
        VK_BLEND_OP_DST_OUT_EXT = 1000148008,
        VK_BLEND_OP_SRC_ATOP_EXT = 1000148009,
        VK_BLEND_OP_DST_ATOP_EXT = 1000148010,
        VK_BLEND_OP_XOR_EXT = 1000148011,
        VK_BLEND_OP_MULTIPLY_EXT = 1000148012,
        VK_BLEND_OP_SCREEN_EXT = 1000148013,
        VK_BLEND_OP_OVERLAY_EXT = 1000148014,
        VK_BLEND_OP_DARKEN_EXT = 1000148015,
        VK_BLEND_OP_LIGHTEN_EXT = 1000148016,
        VK_BLEND_OP_COLORDODGE_EXT = 1000148017,
        VK_BLEND_OP_COLORBURN_EXT = 1000148018,
        VK_BLEND_OP_HARDLIGHT_EXT = 1000148019,
        VK_BLEND_OP_SOFTLIGHT_EXT = 1000148020,
        VK_BLEND_OP_DIFFERENCE_EXT = 1000148021,
        VK_BLEND_OP_EXCLUSION_EXT = 1000148022,
        VK_BLEND_OP_INVERT_EXT = 1000148023,
        VK_BLEND_OP_INVERT_RGB_EXT = 1000148024,
        VK_BLEND_OP_LINEARDODGE_EXT = 1000148025,
        VK_BLEND_OP_LINEARBURN_EXT = 1000148026,
        VK_BLEND_OP_VIVIDLIGHT_EXT = 1000148027,
        VK_BLEND_OP_LINEARLIGHT_EXT = 1000148028,
        VK_BLEND_OP_PINLIGHT_EXT = 1000148029,
        VK_BLEND_OP_HARDMIX_EXT = 1000148030,
        VK_BLEND_OP_HSL_HUE_EXT = 1000148031,
        VK_BLEND_OP_HSL_SATURATION_EXT = 1000148032,
        VK_BLEND_OP_HSL_COLOR_EXT = 1000148033,
        VK_BLEND_OP_HSL_LUMINOSITY_EXT = 1000148034,
        VK_BLEND_OP_PLUS_EXT = 1000148035,
        VK_BLEND_OP_PLUS_CLAMPED_EXT = 1000148036,
        VK_BLEND_OP_PLUS_CLAMPED_ALPHA_EXT = 1000148037,
        VK_BLEND_OP_PLUS_DARKER_EXT = 1000148038,
        VK_BLEND_OP_MINUS_EXT = 1000148039,
        VK_BLEND_OP_MINUS_CLAMPED_EXT = 1000148040,
        VK_BLEND_OP_CONTRAST_EXT = 1000148041,
        VK_BLEND_OP_INVERT_OVG_EXT = 1000148042,
        VK_BLEND_OP_RED_EXT = 1000148043,
        VK_BLEND_OP_GREEN_EXT = 1000148044,
        VK_BLEND_OP_BLUE_EXT = 1000148045,
        VK_BLEND_OP_MAX_ENUM = 0x7FFFFFFF
    } VkBlendOp;

The semantics of each basic blend operations is described in the table below:

Table 33. Basic Blend Operations
VkBlendOp | RGB Components | Alpha Component
--- | --- | ---
`VK_BLEND_OP_ADD` | R = Rs0 × Sr + Rd × Dr G = Gs0 × Sg + Gd × Dg B = Bs0 × Sb + Bd × Db | A = As0 × Sa + Ad × Da
`VK_BLEND_OP_SUBTRACT` | R = Rs0 × Sr - Rd × Dr G = Gs0 × Sg - Gd × Dg B = Bs0 × Sb - Bd × Db | A = As0 × Sa - Ad × Da
`VK_BLEND_OP_REVERSE_SUBTRACT` | R = Rd × Dr - Rs0 × Sr G = Gd × Dg - Gs0 × Sg B = Bd × Db - Bs0 × Sb | A = Ad × Da - As0 × Sa
`VK_BLEND_OP_MIN` | R = min(Rs0,Rd) G = min(Gs0,Gd) B = min(Bs0,Bd) | A = min(As0,Ad)
`VK_BLEND_OP_MAX` | R = max(Rs0,Rd) G = max(Gs0,Gd) B = max(Bs0,Bd) | A = max(As0,Ad)

In this table, the following conventions are used:

- Rs0, Gs0, Bs0 and As0 represent the first source color R, G, B, and A components, respectively.

- Rd, Gd, Bd and Ad represent the R, G, B, and A components of the destination color. That is, the color currently in the corresponding color attachment for this fragment/sample.

- Sr, Sg, Sb and Sa represent the source blend factor R, G, B, and A components, respectively.

- Dr, Dg, Db and Da represent the destination blend factor R, G, B, and A components, respectively.

The blending operation produces a new set of values R, G, B and A, which are written to the framebuffer attachment. If blending is not enabled for this attachment, then R, G, B and A are assigned Rs0, Gs0, Bs0 and As0, respectively.

If the color attachment is fixed-point, the components of the source and destination values and blend factors are each clamped to [0,1] or [-1,1] respectively for an unsigned normalized or signed normalized color attachment prior to evaluating the blend operations. If the color attachment is floating-point, no clamping occurs.

If the numeric format of a framebuffer attachment uses sRGB encoding, the R, G, and B destination color values (after conversion from fixed-point to floating-point) are considered to be encoded for the sRGB color space and hence are linearized prior to their use in blending. Each R, G, and B component is converted from nonlinear to linear as described in the “sRGB EOTF” section of the Khronos Data Format Specification. If the format is not sRGB, no linearization is performed.

If the numeric format of a framebuffer attachment uses sRGB encoding, then the final R, G and B values are converted into the nonlinear sRGB representation before being written to the framebuffer attachment as described in the “sRGB EOTF -1” section of the Khronos Data Format Specification.

If the framebuffer color attachment numeric format is not sRGB encoded then the resulting cs values for R, G and B are unmodified. The value of A is never sRGB encoded. That is, the alpha component is always stored in memory as linear.

If the framebuffer color attachment is `VK_ATTACHMENT_UNUSED`, no writes are performed through that attachment. Framebuffer color attachments greater than or equal to `VkSubpassDescription`::`colorAttachmentCount` perform no writes.

#### 28.1.4. Advanced Blend Operations

The advanced blend operations are those listed in tables f/X/Y/Z Advanced Blend Operations, Hue-Saturation-Luminosity Advanced Blend Operations, and Additional RGB Blend Operations.

If the `pNext` chain of VkPipelineColorBlendStateCreateInfo includes a `VkPipelineColorBlendAdvancedStateCreateInfoEXT` structure, then that structure includes parameters that affect advanced blend operations.

The `VkPipelineColorBlendAdvancedStateCreateInfoEXT` structure is defined as:

    typedef struct VkPipelineColorBlendAdvancedStateCreateInfoEXT {
        VkStructureType      sType;
        const void*          pNext;
        VkBool32             srcPremultiplied;
        VkBool32             dstPremultiplied;
        VkBlendOverlapEXT    blendOverlap;
    } VkPipelineColorBlendAdvancedStateCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `srcPremultiplied` specifies whether the source color of the blend operation is treated as premultiplied.

- `dstPremultiplied` specifies whether the destination color of the blend operation is treated as premultiplied.

- `blendOverlap` is a VkBlendOverlapEXT value specifying how the source and destination sample’s coverage is correlated.

If this structure is not present, `srcPremultiplied` and `dstPremultiplied` are both considered to be `VK_TRUE`, and `blendOverlap` is considered to be `VK_BLEND_OVERLAP_UNCORRELATED_EXT`.

Valid Usage

- If the non-premultiplied source color property is not supported, `srcPremultiplied` must be `VK_TRUE`

- If the non-premultiplied destination color property is not supported, `dstPremultiplied` must be `VK_TRUE`

- If the correlated overlap property is not supported, `blendOverlap` must be `VK_BLEND_OVERLAP_UNCORRELATED_EXT`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_ADVANCED_STATE_CREATE_INFO_EXT`

- `blendOverlap` must be a valid VkBlendOverlapEXT value

When using one of the operations in table f/X/Y/Z Advanced Blend Operations or Hue-Saturation-Luminosity Advanced Blend Operations, blending is performed according to the following equations:

\[\begin{aligned} R & = & f(R_s',R_d')*p_0(A_s,A_d) & + & Y*R_s'*p_1(A_s,A_d) & + & Z*R_d'*p_2(A_s,A_d) \\ G & = & f(G_s',G_d')*p_0(A_s,A_d) & + & Y*G_s'*p_1(A_s,A_d) & + & Z*G_d'*p_2(A_s,A_d) \\ B & = & f(B_s',B_d')*p_0(A_s,A_d) & + & Y*B_s'*p_1(A_s,A_d) & + & Z*B_d'*p_2(A_s,A_d) \\ A & = & X*p_0(A_s,A_d) & + & Y*p_1(A_s,A_d) & + & Z*p_2(A_s,A_d) \end{aligned}\]

where the function f and terms X, Y, and Z are specified in the table. The R, G, and B components of the source color used for blending are derived according to `srcPremultiplied`. If `srcPremultiplied` is set to `VK_TRUE`, the fragment color components are considered to have been premultiplied by the A component prior to blending. The base source color (Rs',Gs',Bs') is obtained by dividing through by the A component:

\[\begin{aligned} (R_s', G_s', B_s') & = \begin{cases} (0, 0, 0) & A_s = 0 \\ (\frac{R_s}{A_s}, \frac{G_s}{A_s}, \frac{B_s}{A_s}) & \text{otherwise} \end{cases} \end{aligned}\]

If `srcPremultiplied` is `VK_FALSE`, the fragment color components are used as the base color:

\[\begin{aligned} (R_s', G_s', B_s') & = (R_s, G_s, B_s) \end{aligned}\]

The R, G, and B components of the destination color used for blending are derived according to `dstPremultiplied`. If `dstPremultiplied` is set to `VK_TRUE`, the destination components are considered to have been premultiplied by the A component prior to blending. The base destination color (Rd',Gd',Bd') is obtained by dividing through by the A component:

\[\begin{aligned} (R_d', G_d', B_d') & = \begin{cases} (0, 0, 0) & A_d = 0 \\ (\frac{R_d}{A_d}, \frac{G_d}{A_d}, \frac{B_d}{A_d}) & \text{otherwise} \end{cases} \end{aligned}\]

If `dstPremultiplied` is `VK_FALSE`, the destination color components are used as the base color:

\[\begin{aligned} (R_d', G_d', B_d') & = (R_d, G_d, B_d) \end{aligned}\]

When blending using advanced blend operations, we expect that the R, G, and B components of premultiplied source and destination color inputs be stored as the product of non-premultiplied R, G, and B component values and the A component of the color. If any R, G, or B component of a premultiplied input color is non-zero and the A component is zero, the color is considered ill-formed, and the corresponding component of the blend result is undefined.

All of the advanced blend operation formulas in this chapter compute the result as a premultiplied color. If `dstPremultiplied` is `VK_FALSE`, that result color’s R, G, and B components are divided by the A component before being written to the framebuffer. If any R, G, or B component of the color is non-zero and the A component is zero, the result is considered ill-formed, and the corresponding component of the blend result is undefined. If all components are zero, that value is unchanged.

If the A component of any input or result color is less than zero, the color is considered ill-formed, and all components of the blend result are undefined.

The weighting functions p0, p1, and p2 are defined in table Advanced Blend Overlap Modes. In these functions, the A components of the source and destination colors are taken to indicate the portion of the pixel covered by the fragment (source) and the fragments previously accumulated in the pixel (destination). The functions p0, p1, and p2 approximate the relative portion of the pixel covered by the intersection of the source and destination, covered only by the source, and covered only by the destination, respectively.

Possible values of VkPipelineColorBlendAdvancedStateCreateInfoEXT::`blendOverlap`, specifying the blend overlap functions, are:

    typedef enum VkBlendOverlapEXT {
        VK_BLEND_OVERLAP_UNCORRELATED_EXT = 0,
        VK_BLEND_OVERLAP_DISJOINT_EXT = 1,
        VK_BLEND_OVERLAP_CONJOINT_EXT = 2,
        VK_BLEND_OVERLAP_MAX_ENUM_EXT = 0x7FFFFFFF
    } VkBlendOverlapEXT;

- `VK_BLEND_OVERLAP_UNCORRELATED_EXT` specifies that there is no correlation between the source and destination coverage.

- `VK_BLEND_OVERLAP_CONJOINT_EXT` specifies that the source and destination coverage are considered to have maximal overlap.

- `VK_BLEND_OVERLAP_DISJOINT_EXT` specifies that the source and destination coverage are considered to have minimal overlap.

Table 34. Advanced Blend Overlap Modes
Overlap Mode | Weighting Equations
--- | ---
`VK_BLEND_OVERLAP_UNCORRELATED_EXT` | \[ \begin{aligned} p_0(A_s,A_d) & = A_sA_d \\ p_1(A_s,A_d) & = A_s(1-A_d) \\ p_2(A_s,A_d) & = A_d(1-A_s) \\ \end{aligned}\]
`VK_BLEND_OVERLAP_CONJOINT_EXT` | \[ \begin{aligned} p_0(A_s,A_d) & = min(A_s,A_d) \\ p_1(A_s,A_d) & = max(A_s-A_d,0) \\ p_2(A_s,A_d) & = max(A_d-A_s,0) \\ \end{aligned}\]
`VK_BLEND_OVERLAP_DISJOINT_EXT` | \[ \begin{aligned} p_0(A_s,A_d) & = max(A_s+A_d-1,0) \\ p_1(A_s,A_d) & = min(A_s,1-A_d) \\ p_2(A_s,A_d) & = min(A_d,1-A_s) \\ \end{aligned}\]

Table 35. f/X/Y/Z Advanced Blend Operations
Mode | Blend Coefficients
--- | ---
`VK_BLEND_OP_ZERO_EXT` | \[ \begin{aligned} (X,Y,Z) & = (0,0,0) \\ f(C_s,C_d) & = 0 \end{aligned}\]
`VK_BLEND_OP_SRC_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,0) \\ f(C_s,C_d) & = C_s \end{aligned}\]
`VK_BLEND_OP_DST_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,0,1) \\ f(C_s,C_d) & = C_d \end{aligned}\]
`VK_BLEND_OP_SRC_OVER_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,1) \\ f(C_s,C_d) & = C_s \end{aligned}\]
`VK_BLEND_OP_DST_OVER_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,1) \\ f(C_s,C_d) & = C_d \end{aligned}\]
`VK_BLEND_OP_SRC_IN_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,0,0) \\ f(C_s,C_d) & = C_s \end{aligned}\]
`VK_BLEND_OP_DST_IN_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,0,0) \\ f(C_s,C_d) & = C_d \end{aligned}\]
`VK_BLEND_OP_SRC_OUT_EXT` | \[ \begin{aligned} (X,Y,Z) & = (0,1,0) \\ f(C_s,C_d) & = 0 \end{aligned}\]
`VK_BLEND_OP_DST_OUT_EXT` | \[ \begin{aligned} (X,Y,Z) & = (0,0,1) \\ f(C_s,C_d) & = 0 \end{aligned}\]
`VK_BLEND_OP_SRC_ATOP_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,0,1) \\ f(C_s,C_d) & = C_s \end{aligned}\]
`VK_BLEND_OP_DST_ATOP_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,0) \\ f(C_s,C_d) & = C_d \end{aligned}\]
`VK_BLEND_OP_XOR_EXT` | \[ \begin{aligned} (X,Y,Z) & = (0,1,1) \\ f(C_s,C_d) & = 0 \end{aligned}\]
`VK_BLEND_OP_MULTIPLY_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,1) \\ f(C_s,C_d) & = C_sC_d \end{aligned}\]
`VK_BLEND_OP_SCREEN_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,1) \\ f(C_s,C_d) & = C_s+C_d-C_sC_d \end{aligned}\]
`VK_BLEND_OP_OVERLAY_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,1) \\ f(C_s,C_d) & = \begin{cases} 2 C_sC_d & C_d \leq 0.5 \\ 1-2 (1-C_s)(1-C_d) & \text{otherwise} \end{cases} \end{aligned}\]
`VK_BLEND_OP_DARKEN_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,1) \\ f(C_s,C_d) & = min(C_s,C_d) \end{aligned}\]
`VK_BLEND_OP_LIGHTEN_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,1) \\ f(C_s,C_d) & = max(C_s,C_d) \end{aligned}\]
`VK_BLEND_OP_COLORDODGE_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,1) \\ f(C_s,C_d) & = \begin{cases} 0 & C_d \leq 0 \\ min(1,\frac{C_d}{1-C_s}) & C_d \gt 0 \text{ and } C_s \lt 1 \\ 1 & C_d \gt 0 \text{ and } C_s \geq 1 \end{cases} \end{aligned}\]
`VK_BLEND_OP_COLORBURN_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,1) \\ f(C_s,C_d) & = \begin{cases} 1 & C_d \geq 1 \\ 1 - min(1,\frac{1-C_d}{C_s}) & C_d \lt 1 \text{ and } C_s \gt 0 \\ 0 & C_d \lt 1 \text{ and } C_s \leq 0 \end{cases} \end{aligned}\]
`VK_BLEND_OP_HARDLIGHT_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,1) \\ f(C_s,C_d) & = \begin{cases} 2 C_sC_d & C_s \leq 0.5 \\ 1-2 (1-C_s)(1-C_d) & \text{otherwise} \end{cases} \end{aligned}\]
`VK_BLEND_OP_SOFTLIGHT_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,1) \\ f(C_s,C_d) & = \begin{cases} C_d-(1-2 C_s)C_d(1-C_d) & C_s \leq 0.5 \\ C_d+(2 C_s-1)C_d((16 C_d-12)C_d+3) & C_s \gt 0.5 \text{ and } C_d \leq 0.25 \\ C_d+(2 C_s-1)(\sqrt{C_d}-C_d) & C_s \gt 0.5 \text{ and } C_d \gt 0.25 \end{cases} \end{aligned}\]
`VK_BLEND_OP_DIFFERENCE_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,1) \\ f(C_s,C_d) & = \lvert C_d-C_s \rvert \end{aligned}\]
`VK_BLEND_OP_EXCLUSION_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,1) \\ f(C_s,C_d) & = C_s+C_d-2C_sC_d \end{aligned}\]
`VK_BLEND_OP_INVERT_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,0,1) \\ f(C_s,C_d) & = 1-C_d \end{aligned}\]
`VK_BLEND_OP_INVERT_RGB_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,0,1) \\ f(C_s,C_d) & = C_s(1-C_d) \end{aligned}\]
`VK_BLEND_OP_LINEARDODGE_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,1) \\ f(C_s,C_d) & = \begin{cases} C_s+C_d & C_s+C_d \leq 1 \\ 1 & \text{otherwise} \end{cases} \end{aligned}\]
`VK_BLEND_OP_LINEARBURN_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,1) \\ f(C_s,C_d) & = \begin{cases} C_s+C_d-1 & C_s+C_d \gt 1 \\ 0 & \text{otherwise} \end{cases} \end{aligned}\]
`VK_BLEND_OP_VIVIDLIGHT_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,1) \\ f(C_s,C_d) & = \begin{cases} 1-min(1,\frac{1-C_d}{2C_s}) & 0 \lt C_s \lt 0.5 \\ 0 & C_s \leq 0 \\ min(1,\frac{C_d}{2(1-C_s)}) & 0.5 \leq C_s \lt 1 \\ 1 & C_s \geq 1 \end{cases} \end{aligned}\]
`VK_BLEND_OP_LINEARLIGHT_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,1) \\ f(C_s,C_d) & = \begin{cases} 1 & 2C_s+C_d \gt 2 \\ 2C_s+C_d-1 & 1 \lt 2C_s+C_d \leq 2 \\ 0 & 2C_s+C_d \leq 1 \end{cases} \end{aligned}\]
`VK_BLEND_OP_PINLIGHT_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,1) \\ f(C_s,C_d) & = \begin{cases} 0 & 2C_s-1 \gt C_d \text{ and } C_s \lt 0.5 \\ 2C_s-1 & 2C_s-1 \gt C_d \text{ and } C_s \geq 0.5 \\ 2C_s & 2C_s-1 \leq C_d \text{ and } C_s \lt 0.5C_d \\ C_d & 2C_s-1 \leq C_d \text{ and } C_s \geq 0.5C_d \end{cases} \end{aligned}\]
`VK_BLEND_OP_HARDMIX_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,1) \\ f(C_s,C_d) & = \begin{cases} 0 & C_s+C_d \lt 1 \\ 1 & \text{otherwise} \end{cases} \end{aligned}\]

When using one of the HSL blend operations in table Hue-Saturation-Luminosity Advanced Blend Operations as the blend operation, the RGB color components produced by the function f are effectively obtained by converting both the non-premultiplied source and destination colors to the HSL (hue, saturation, luminosity) color space, generating a new HSL color by selecting H, S, and L components from the source or destination according to the blend operation, and then converting the result back to RGB. In the equations below, a blended RGB color is produced according to the following pseudocode:

      float minv3(vec3 c) {
        return min(min(c.r, c.g), c.b);
      }
      float maxv3(vec3 c) {
        return max(max(c.r, c.g), c.b);
      }
      float lumv3(vec3 c) {
        return dot(c, vec3(0.30, 0.59, 0.11));
      }
      float satv3(vec3 c) {
        return maxv3(c) - minv3(c);
      }

      // If any color components are outside [0,1], adjust the color to
      // get the components in range.
      vec3 ClipColor(vec3 color) {
        float lum = lumv3(color);
        float mincol = minv3(color);
        float maxcol = maxv3(color);
        if (mincol < 0.0) {
          color = lum + ((color-lum)*lum) / (lum-mincol);
        }
        if (maxcol > 1.0) {
          color = lum + ((color-lum)*(1-lum)) / (maxcol-lum);
        }
        return color;
      }

      // Take the base RGB color <cbase> and override its luminosity
      // with that of the RGB color <clum>.
      vec3 SetLum(vec3 cbase, vec3 clum) {
        float lbase = lumv3(cbase);
        float llum = lumv3(clum);
        float ldiff = llum - lbase;
        vec3 color = cbase + vec3(ldiff);
        return ClipColor(color);
      }

      // Take the base RGB color <cbase> and override its saturation with
      // that of the RGB color <csat>.  The override the luminosity of the
      // result with that of the RGB color <clum>.
      vec3 SetLumSat(vec3 cbase, vec3 csat, vec3 clum)
      {
        float minbase = minv3(cbase);
        float sbase = satv3(cbase);
        float ssat = satv3(csat);
        vec3 color;
        if (sbase > 0) {
          // Equivalent (modulo rounding errors) to setting the
          // smallest (R,G,B) component to 0, the largest to <ssat>,
          // and interpolating the "middle" component based on its
          // original value relative to the smallest/largest.
          color = (cbase - minbase) * ssat / sbase;
        } else {
          color = vec3(0.0);
        }
        return SetLum(color, clum);
      }

Table 36. Hue-Saturation-Luminosity Advanced Blend Operations
Mode | Result
--- | ---
`VK_BLEND_OP_HSL_HUE_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,1) \\ f(C_s,C_d) & = SetLumSat(C_s,C_d,C_d) \end{aligned}\]
`VK_BLEND_OP_HSL_SATURATION_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,1) \\ f(C_s,C_d) & = SetLumSat(C_d,C_s,C_d) \end{aligned}\]
`VK_BLEND_OP_HSL_COLOR_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,1) \\ f(C_s,C_d) & = SetLum(C_s,C_d) \end{aligned}\]
`VK_BLEND_OP_HSL_LUMINOSITY_EXT` | \[ \begin{aligned} (X,Y,Z) & = (1,1,1) \\ f(C_s,C_d) & = SetLum(C_d,C_s) \end{aligned}\]

When using one of the operations in table Additional RGB Blend Operations as the blend operation, the source and destination colors used by these blending operations are interpreted according to `srcPremultiplied` and `dstPremultiplied`. The blending operations below are evaluated where the RGB source and destination color components are both considered to have been premultiplied by the corresponding A component.

\[\begin{aligned} (R_s', G_s', B_s') & = \begin{cases} (R_s, G_s, B_s) & \text{if srcPremultiplied is VK\_TRUE} \\ (R_sA_s, G_sA_s, B_sA_s) & \text{if srcPremultiplied is VK\_FALSE} \end{cases} \\ (R_d', G_d', B_d') & = \begin{cases} (R_d, G_d, B_d) & \text{if dstPremultiplied is VK\_TRUE} \\ (R_dA_d, G_dA_d, B_dA_d) & \text{if dstPremultiplied is VK\_FALSE} \end{cases} \end{aligned}\]

Table 37. Additional RGB Blend Operations
Mode | Result
--- | ---
`VK_BLEND_OP_PLUS_EXT` | \[ \begin{aligned} (R,G,B,A) = ( & R_s'+R_d', \\ & G_s'+G_d', \\ & B_s'+B_d', \\ & A_s+A_d) \end{aligned}\]
`VK_BLEND_OP_PLUS_CLAMPED_EXT` | \[ \begin{aligned} (R,G,B,A) = ( & min(1,R_s'+R_d'), \\ & min(1,G_s'+G_d'), \\ & min(1,B_s'+B_d'), \\ & min(1,A_s+A_d)) \end{aligned}\]
`VK_BLEND_OP_PLUS_CLAMPED_ALPHA_EXT` | \[ \begin{aligned} (R,G,B,A) = ( & min(min(1,A_s+A_d),R_s'+R_d'), \\ & min(min(1,A_s+A_d),G_s'+G_d'), \\ & min(min(1,A_s+A_d),B_s'+B_d'), \\ & min(1,A_s+A_d)) \end{aligned}\]
`VK_BLEND_OP_PLUS_DARKER_EXT` | \[ \begin{aligned} (R,G,B,A) = ( & max(0,min(1,A_s+A_d)-((A_s-R_s')+(A_d-R_d'))), \\ & max(0,min(1,A_s+A_d)-((A_s-G_s')+(A_d-G_d'))), \\ & max(0,min(1,A_s+A_d)-((A_s-B_s')+(A_d-B_d'))), \\ & min(1,A_s+A_d)) \end{aligned}\]
`VK_BLEND_OP_MINUS_EXT` | \[ \begin{aligned} (R,G,B,A) = ( & R_d'-R_s', \\ & G_d'-G_s', \\ & B_d'-B_s', \\ & A_d-A_s) \end{aligned}\]
`VK_BLEND_OP_MINUS_CLAMPED_EXT` | \[ \begin{aligned} (R,G,B,A) = ( & max(0,R_d'-R_s'), \\ & max(0,G_d'-G_s'), \\ & max(0,B_d'-B_s'), \\ & max(0,A_d-A_s)) \end{aligned}\]
`VK_BLEND_OP_CONTRAST_EXT` | \[ \begin{aligned} (R,G,B,A) = ( & \frac{A_d}{2} + 2(R_d'-\frac{A_d}{2})(R_s'-\frac{A_s}{2}), \\ & \frac{A_d}{2} + 2(G_d'-\frac{A_d}{2})(G_s'-\frac{A_s}{2}), \\ & \frac{A_d}{2} + 2(B_d'-\frac{A_d}{2})(B_s'-\frac{A_s}{2}), \\ & A_d) \end{aligned}\]
`VK_BLEND_OP_INVERT_OVG_EXT` | \[ \begin{aligned} (R,G,B,A) = ( & A_s(1-R_d') + (1-A_s)R_d', \\ & A_s(1-G_d') + (1-A_s)G_d', \\ & A_s(1-B_d') + (1-A_s)B_d', \\ & A_s+A_d-A_sA_d) \end{aligned}\]
`VK_BLEND_OP_RED_EXT` | \[ \begin{aligned} (R,G,B,A) & = (R_s', G_d', B_d', A_d) \end{aligned}\]
`VK_BLEND_OP_GREEN_EXT` | \[ \begin{aligned} (R,G,B,A) & = (R_d', G_s', B_d', A_d) \end{aligned}\]
`VK_BLEND_OP_BLUE_EXT` | \[ \begin{aligned} (R,G,B,A) & = (R_d', G_d', B_s', A_d) \end{aligned}\]

### 28.2. Logical Operations

The application can enable a logical operation between the fragment’s color values and the existing value in the framebuffer attachment. This logical operation is applied prior to updating the framebuffer attachment. Logical operations are applied only for signed and unsigned integer and normalized integer framebuffers. Logical operations are not applied to floating-point or sRGB format color attachments.

Logical operations are controlled by the `logicOpEnable` and `logicOp` members of VkPipelineColorBlendStateCreateInfo. If `logicOpEnable` is `VK_TRUE`, then a logical operation selected by `logicOp` is applied between each color attachment and the fragment’s corresponding output value, and blending of all attachments is treated as if it were disabled. Any attachments using color formats for which logical operations are not supported simply pass through the color values unmodified. The logical operation is applied independently for each of the red, green, blue, and alpha components. The `logicOp` is selected from the following operations:

    typedef enum VkLogicOp {
        VK_LOGIC_OP_CLEAR = 0,
        VK_LOGIC_OP_AND = 1,
        VK_LOGIC_OP_AND_REVERSE = 2,
        VK_LOGIC_OP_COPY = 3,
        VK_LOGIC_OP_AND_INVERTED = 4,
        VK_LOGIC_OP_NO_OP = 5,
        VK_LOGIC_OP_XOR = 6,
        VK_LOGIC_OP_OR = 7,
        VK_LOGIC_OP_NOR = 8,
        VK_LOGIC_OP_EQUIVALENT = 9,
        VK_LOGIC_OP_INVERT = 10,
        VK_LOGIC_OP_OR_REVERSE = 11,
        VK_LOGIC_OP_COPY_INVERTED = 12,
        VK_LOGIC_OP_OR_INVERTED = 13,
        VK_LOGIC_OP_NAND = 14,
        VK_LOGIC_OP_SET = 15,
        VK_LOGIC_OP_MAX_ENUM = 0x7FFFFFFF
    } VkLogicOp;

The logical operations supported by Vulkan are summarized in the following table in which

- ¬ is bitwise invert,

- ∧ is bitwise and,

- ∨ is bitwise or,

- ⊕ is bitwise exclusive or,

- s is the fragment’s Rs0, Gs0, Bs0 or As0 component value for the fragment output corresponding to the color attachment being updated, and

- d is the color attachment’s R, G, B or A component value:

Table 38. Logical Operations
Mode | Operation
--- | ---
`VK_LOGIC_OP_CLEAR` | 0
`VK_LOGIC_OP_AND` | s ∧ d
`VK_LOGIC_OP_AND_REVERSE` | s ∧ ¬ d
`VK_LOGIC_OP_COPY` | s
`VK_LOGIC_OP_AND_INVERTED` | ¬ s ∧ d
`VK_LOGIC_OP_NO_OP` | d
`VK_LOGIC_OP_XOR` | s ⊕ d
`VK_LOGIC_OP_OR` | s ∨ d
`VK_LOGIC_OP_NOR` | ¬ (s ∨ d)
`VK_LOGIC_OP_EQUIVALENT` | ¬ (s ⊕ d)
`VK_LOGIC_OP_INVERT` | ¬ d
`VK_LOGIC_OP_OR_REVERSE` | s ∨ ¬ d
`VK_LOGIC_OP_COPY_INVERTED` | ¬ s
`VK_LOGIC_OP_OR_INVERTED` | ¬ s ∨ d
`VK_LOGIC_OP_NAND` | ¬ (s ∧ d)
`VK_LOGIC_OP_SET` | all 1s

The result of the logical operation is then written to the color attachment as controlled by the component write mask, described in Blend Operations.

### 28.3. Color Write Mask

Bits which can be set in VkPipelineColorBlendAttachmentState::`colorWriteMask` to determine whether the final color values R, G, B and A are written to the framebuffer attachment are:

    typedef enum VkColorComponentFlagBits {
        VK_COLOR_COMPONENT_R_BIT = 0x00000001,
        VK_COLOR_COMPONENT_G_BIT = 0x00000002,
        VK_COLOR_COMPONENT_B_BIT = 0x00000004,
        VK_COLOR_COMPONENT_A_BIT = 0x00000008,
        VK_COLOR_COMPONENT_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkColorComponentFlagBits;

- `VK_COLOR_COMPONENT_R_BIT` specifies that the R value is written to the color attachment for the appropriate sample. Otherwise, the value in memory is unmodified.

- `VK_COLOR_COMPONENT_G_BIT` specifies that the G value is written to the color attachment for the appropriate sample. Otherwise, the value in memory is unmodified.

- `VK_COLOR_COMPONENT_B_BIT` specifies that the B value is written to the color attachment for the appropriate sample. Otherwise, the value in memory is unmodified.

- `VK_COLOR_COMPONENT_A_BIT` specifies that the A value is written to the color attachment for the appropriate sample. Otherwise, the value in memory is unmodified.

The color write mask operation is applied regardless of whether blending is enabled.

    typedef VkFlags VkColorComponentFlags;

`VkColorComponentFlags` is a bitmask type for setting a mask of zero or more VkColorComponentFlagBits.

## 29. Dispatching Commands

Dispatching commands (commands with `Dispatch` in the name) provoke work in a compute pipeline. Dispatching commands are recorded into a command buffer and when executed by a queue, will produce work which executes according to the bound compute pipeline. A compute pipeline must be bound to a command buffer before any dispatch commands are recorded in that command buffer.

To record a dispatch, call:

    void vkCmdDispatch(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    groupCountX,
        uint32_t                                    groupCountY,
        uint32_t                                    groupCountZ);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `groupCountX` is the number of local workgroups to dispatch in the X dimension.

- `groupCountY` is the number of local workgroups to dispatch in the Y dimension.

- `groupCountZ` is the number of local workgroups to dispatch in the Z dimension.

When the command is executed, a global workgroup consisting of `groupCountX` × `groupCountY` × `groupCountZ` local workgroups is assembled.

Valid Usage

- If a `VkImageView` is sampled with `VK_FILTER_LINEAR` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT`

- If a `VkImageView` is accessed using atomic operations as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT`

- If a `VkImageView` is sampled with `VK_FILTER_CUBIC_EXT` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_EXT`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` as a result of this command must have a VkImageViewType and format that supports cubic filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubic` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` with a reduction mode of either `VK_SAMPLER_REDUCTION_MODE_MIN` or `VK_SAMPLER_REDUCTION_MODE_MAX` as a result of this command must have a VkImageViewType and format that supports cubic filtering together with minmax filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubicMinmax` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImage created with a VkImageCreateInfo::`flags` containing `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV` sampled as a result of this command must only be sampled using a VkSamplerAddressMode of `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`.

- For each set n that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a descriptor set must have been bound to n at the same pipeline bind point, with a `VkPipelineLayout` that is compatible for set n, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- For each push constant that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a push constant value must have been set for the same pipeline bind point, with a `VkPipelineLayout` that is compatible for push constants, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- Descriptors in each bound descriptor set, specified via `vkCmdBindDescriptorSets`, must be valid if they are statically used by the `VkPipeline` bound to the pipeline bind point used by this command

- A valid pipeline must be bound to the pipeline bind point used by this command

- If the `VkPipeline` object bound to the pipeline bind point used by this command requires any dynamic state, that state must have been set for `commandBuffer`, and done so after any previously bound pipeline with the corresponding state not specified as dynamic

- There must not have been any calls to dynamic state setting commands for any state not specified as dynamic in the `VkPipeline` object bound to the pipeline bind point used by this command, since that pipeline was bound

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used to sample from any `VkImage` with a `VkImageView` of the type `VK_IMAGE_VIEW_TYPE_3D`, `VK_IMAGE_VIEW_TYPE_CUBE`, `VK_IMAGE_VIEW_TYPE_1D_ARRAY`, `VK_IMAGE_VIEW_TYPE_2D_ARRAY` or `VK_IMAGE_VIEW_TYPE_CUBE_ARRAY`, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions with `ImplicitLod`, `Dref` or `Proj` in their name, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions that includes a LOD bias or any offset values, in any shader stage

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a uniform buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a storage buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If `commandBuffer` is an unprotected command buffer, any resource accessed by the `VkPipeline` object bound to the pipeline bind point used by this command must not be a protected resource

- If `commandBuffer` is a protected command buffer, any resource written to by the `VkPipeline` object bound to the pipeline bind point used by this command must not be an unprotected resource

- If `commandBuffer` is a protected command buffer, pipeline stages other than the framebuffer-space and compute stages in the `VkPipeline` object bound to the pipeline bind point must not write to any resource

- `groupCountX` must be less than or equal to `VkPhysicalDeviceLimits`::`maxComputeWorkGroupCount`[0]

- `groupCountY` must be less than or equal to `VkPhysicalDeviceLimits`::`maxComputeWorkGroupCount`[1]

- `groupCountZ` must be less than or equal to `VkPhysicalDeviceLimits`::`maxComputeWorkGroupCount`[2]

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support compute operations

- This command must only be called outside of a render pass instance

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Compute | Compute

To record an indirect command dispatch, call:

    void vkCmdDispatchIndirect(
        VkCommandBuffer                             commandBuffer,
        VkBuffer                                    buffer,
        VkDeviceSize                                offset);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `buffer` is the buffer containing dispatch parameters.

- `offset` is the byte offset into `buffer` where parameters begin.

`vkCmdDispatchIndirect` behaves similarly to vkCmdDispatch except that the parameters are read by the device from a buffer during execution. The parameters of the dispatch are encoded in a VkDispatchIndirectCommand structure taken from `buffer` starting at `offset`.

Valid Usage

- If a `VkImageView` is sampled with `VK_FILTER_LINEAR` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT`

- If a `VkImageView` is accessed using atomic operations as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT`

- If a `VkImageView` is sampled with `VK_FILTER_CUBIC_EXT` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_EXT`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` as a result of this command must have a VkImageViewType and format that supports cubic filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubic` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` with a reduction mode of either `VK_SAMPLER_REDUCTION_MODE_MIN` or `VK_SAMPLER_REDUCTION_MODE_MAX` as a result of this command must have a VkImageViewType and format that supports cubic filtering together with minmax filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubicMinmax` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImage created with a VkImageCreateInfo::`flags` containing `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV` sampled as a result of this command must only be sampled using a VkSamplerAddressMode of `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`.

- For each set n that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a descriptor set must have been bound to n at the same pipeline bind point, with a `VkPipelineLayout` that is compatible for set n, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- For each push constant that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a push constant value must have been set for the same pipeline bind point, with a `VkPipelineLayout` that is compatible for push constants, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- Descriptors in each bound descriptor set, specified via `vkCmdBindDescriptorSets`, must be valid if they are statically used by the `VkPipeline` bound to the pipeline bind point used by this command

- A valid pipeline must be bound to the pipeline bind point used by this command

- If the `VkPipeline` object bound to the pipeline bind point used by this command requires any dynamic state, that state must have been set for `commandBuffer`, and done so after any previously bound pipeline with the corresponding state not specified as dynamic

- There must not have been any calls to dynamic state setting commands for any state not specified as dynamic in the `VkPipeline` object bound to the pipeline bind point used by this command, since that pipeline was bound

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used to sample from any `VkImage` with a `VkImageView` of the type `VK_IMAGE_VIEW_TYPE_3D`, `VK_IMAGE_VIEW_TYPE_CUBE`, `VK_IMAGE_VIEW_TYPE_1D_ARRAY`, `VK_IMAGE_VIEW_TYPE_2D_ARRAY` or `VK_IMAGE_VIEW_TYPE_CUBE_ARRAY`, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions with `ImplicitLod`, `Dref` or `Proj` in their name, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions that includes a LOD bias or any offset values, in any shader stage

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a uniform buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a storage buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If `commandBuffer` is an unprotected command buffer, any resource accessed by the `VkPipeline` object bound to the pipeline bind point used by this command must not be a protected resource

- If `buffer` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `buffer` must have been created with the `VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT` bit set

- `offset` must be a multiple of `4`

- `commandBuffer` must not be a protected command buffer

- The sum of `offset` and the size of `VkDispatchIndirectCommand` must be less than or equal to the size of `buffer`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `buffer` must be a valid VkBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support compute operations

- This command must only be called outside of a render pass instance

- Both of `buffer`, and `commandBuffer` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Compute | Compute

The `VkDispatchIndirectCommand` structure is defined as:

    typedef struct VkDispatchIndirectCommand {
        uint32_t    x;
        uint32_t    y;
        uint32_t    z;
    } VkDispatchIndirectCommand;

- `x` is the number of local workgroups to dispatch in the X dimension.

- `y` is the number of local workgroups to dispatch in the Y dimension.

- `z` is the number of local workgroups to dispatch in the Z dimension.

The members of `VkDispatchIndirectCommand` have the same meaning as the corresponding parameters of vkCmdDispatch.

Valid Usage

- `x` must be less than or equal to `VkPhysicalDeviceLimits`::`maxComputeWorkGroupCount`[0]

- `y` must be less than or equal to `VkPhysicalDeviceLimits`::`maxComputeWorkGroupCount`[1]

- `z` must be less than or equal to `VkPhysicalDeviceLimits`::`maxComputeWorkGroupCount`[2]

To record a dispatch using non-zero base values for the components of `WorkgroupId`, call:

    void vkCmdDispatchBase(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    baseGroupX,
        uint32_t                                    baseGroupY,
        uint32_t                                    baseGroupZ,
        uint32_t                                    groupCountX,
        uint32_t                                    groupCountY,
        uint32_t                                    groupCountZ);

or the equivalent command

    void vkCmdDispatchBaseKHR(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    baseGroupX,
        uint32_t                                    baseGroupY,
        uint32_t                                    baseGroupZ,
        uint32_t                                    groupCountX,
        uint32_t                                    groupCountY,
        uint32_t                                    groupCountZ);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `baseGroupX` is the start value for the X component of `WorkgroupId`.

- `baseGroupY` is the start value for the Y component of `WorkgroupId`.

- `baseGroupZ` is the start value for the Z component of `WorkgroupId`.

- `groupCountX` is the number of local workgroups to dispatch in the X dimension.

- `groupCountY` is the number of local workgroups to dispatch in the Y dimension.

- `groupCountZ` is the number of local workgroups to dispatch in the Z dimension.

When the command is executed, a global workgroup consisting of `groupCountX` × `groupCountY` × `groupCountZ` local workgroups is assembled, with `WorkgroupId` values ranging from [`baseGroup*`, `baseGroup*` + `groupCount*`) in each component. vkCmdDispatch is equivalent to `vkCmdDispatchBase(0,0,0,groupCountX,groupCountY,groupCountZ)`.

Valid Usage

- If a `VkImageView` is sampled with `VK_FILTER_LINEAR` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT`

- If a `VkImageView` is accessed using atomic operations as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT`

- If a `VkImageView` is sampled with `VK_FILTER_CUBIC_EXT` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_EXT`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` as a result of this command must have a VkImageViewType and format that supports cubic filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubic` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` with a reduction mode of either `VK_SAMPLER_REDUCTION_MODE_MIN` or `VK_SAMPLER_REDUCTION_MODE_MAX` as a result of this command must have a VkImageViewType and format that supports cubic filtering together with minmax filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubicMinmax` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImage created with a VkImageCreateInfo::`flags` containing `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV` sampled as a result of this command must only be sampled using a VkSamplerAddressMode of `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`.

- For each set n that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a descriptor set must have been bound to n at the same pipeline bind point, with a `VkPipelineLayout` that is compatible for set n, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- For each push constant that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a push constant value must have been set for the same pipeline bind point, with a `VkPipelineLayout` that is compatible for push constants, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- Descriptors in each bound descriptor set, specified via `vkCmdBindDescriptorSets`, must be valid if they are statically used by the `VkPipeline` bound to the pipeline bind point used by this command

- A valid pipeline must be bound to the pipeline bind point used by this command

- If the `VkPipeline` object bound to the pipeline bind point used by this command requires any dynamic state, that state must have been set for `commandBuffer`, and done so after any previously bound pipeline with the corresponding state not specified as dynamic

- There must not have been any calls to dynamic state setting commands for any state not specified as dynamic in the `VkPipeline` object bound to the pipeline bind point used by this command, since that pipeline was bound

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used to sample from any `VkImage` with a `VkImageView` of the type `VK_IMAGE_VIEW_TYPE_3D`, `VK_IMAGE_VIEW_TYPE_CUBE`, `VK_IMAGE_VIEW_TYPE_1D_ARRAY`, `VK_IMAGE_VIEW_TYPE_2D_ARRAY` or `VK_IMAGE_VIEW_TYPE_CUBE_ARRAY`, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions with `ImplicitLod`, `Dref` or `Proj` in their name, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions that includes a LOD bias or any offset values, in any shader stage

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a uniform buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a storage buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If `commandBuffer` is an unprotected command buffer, any resource accessed by the `VkPipeline` object bound to the pipeline bind point used by this command must not be a protected resource

- `baseGroupX` must be less than `VkPhysicalDeviceLimits`::`maxComputeWorkGroupCount`[0]

- `baseGroupX` must be less than `VkPhysicalDeviceLimits`::`maxComputeWorkGroupCount`[1]

- `baseGroupZ` must be less than `VkPhysicalDeviceLimits`::`maxComputeWorkGroupCount`[2]

- `groupCountX` must be less than or equal to `VkPhysicalDeviceLimits`::`maxComputeWorkGroupCount`[0] minus `baseGroupX`

- `groupCountY` must be less than or equal to `VkPhysicalDeviceLimits`::`maxComputeWorkGroupCount`[1] minus `baseGroupY`

- `groupCountZ` must be less than or equal to `VkPhysicalDeviceLimits`::`maxComputeWorkGroupCount`[2] minus `baseGroupZ`

- If any of `baseGroupX`, `baseGroupY`, or `baseGroupZ` are not zero, then the bound compute pipeline must have been created with the `VK_PIPELINE_CREATE_DISPATCH_BASE` flag.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support compute operations

- This command must only be called outside of a render pass instance

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Compute |

## 30. Device-Generated Commands

This chapter discusses the generation of command buffer content on the device, for which these principle steps are to be taken:

- Define via `VkIndirectCommandsLayoutNV` the sequence of commands which should be generated.

- Optionally make use of device-bindable Shader Groups.

- Retrieve device addresses by vkGetBufferDeviceAddressEXT for setting buffers on the device.

- Fill one or more `VkBuffer` with the appropriate content that gets interpreted by `VkIndirectCommandsLayoutNV`.

- Create a `preprocess` `VkBuffer` using the allocation information from vkGetGeneratedCommandsMemoryRequirementsNV.

- Optionally preprocess the input data using vkCmdPreprocessGeneratedCommandsNV in a separate action.

- Generate and execute the actual commands via vkCmdExecuteGeneratedCommandsNV passing all required data.

vkCmdPreprocessGeneratedCommandsNV executes in a separate logical pipeline from either graphics or compute. When preprocessing commands in a separate step they must be explicitly synchronized against the command execution. When not preprocessing, the preprocessing is automatically synchronized against the command execution.

### 30.1. Indirect Commands Layout

The device-side command generation happens through an iterative processing of an atomic sequence comprised of command tokens, which are represented by:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkIndirectCommandsLayoutNV)

#### 30.1.1. Creation and Deletion

Indirect command layouts are created by:

    VkResult vkCreateIndirectCommandsLayoutNV(
        VkDevice                                    device,
        const VkIndirectCommandsLayoutCreateInfoNV* pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkIndirectCommandsLayoutNV*                 pIndirectCommandsLayout);

- `device` is the logical device that creates the indirect command layout.

- `pCreateInfo` is a pointer to an instance of the `VkIndirectCommandsLayoutCreateInfoNV` structure containing parameters affecting creation of the indirect command layout.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pIndirectCommandsLayout` points to a `VkIndirectCommandsLayoutNV` handle in which the resulting indirect command layout is returned.

Valid Usage

- The `VkPhysicalDeviceDeviceGeneratedCommandsFeaturesNV`→`deviceGeneratedCommands` feature must be enabled

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkIndirectCommandsLayoutCreateInfoNV structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pIndirectCommandsLayout` must be a valid pointer to a VkIndirectCommandsLayoutNV handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkIndirectCommandsLayoutCreateInfoNV` structure is defined as:

    typedef struct VkIndirectCommandsLayoutCreateInfoNV {
        VkStructureType                           sType;
        const void*                               pNext;
        VkIndirectCommandsLayoutUsageFlagsNV      flags;
        VkPipelineBindPoint                       pipelineBindPoint;
        uint32_t                                  tokenCount;
        const VkIndirectCommandsLayoutTokenNV*    pTokens;
        uint32_t                                  streamCount;
        const uint32_t*                           pStreamStrides;
    } VkIndirectCommandsLayoutCreateInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `pipelineBindPoint` is the VkPipelineBindPoint that this layout targets.

- `flags` is a bitmask of VkIndirectCommandsLayoutUsageFlagBitsNV specifying usage hints of this layout.

- `tokenCount` is the length of the individual command sequence.

- `pTokens` is an array describing each command token in detail. See VkIndirectCommandsTokenTypeNV and VkIndirectCommandsLayoutTokenNV below for details.

- `streamCount` is the number of streams used to provide the token inputs.

- `pStreamStrides` is an array defining the byte stride for each input stream.

The following code illustrates some of the flags:

    void cmdProcessAllSequences(cmd, pipeline, indirectCommandsLayout, pIndirectCommandsTokens, sequencesCount, indexbuffer, indexbufferOffset)
    {
      for (s = 0; s < sequencesCount; s++)
      {
        sUsed = s;

        if (indirectCommandsLayout.flags & VK_INDIRECT_COMMANDS_LAYOUT_USAGE_INDEXED_SEQUENCES_BIT_NV) {
          sUsed = indexbuffer.load_uint32( sUsed * sizeof(uint32_t) + indexbufferOffset);
        }

        if (indirectCommandsLayout.flags & VK_INDIRECT_COMMANDS_LAYOUT_USAGE_UNORDERED_SEQUENCES_BIT_NV) {
          sUsed = incoherent_implementation_dependent_permutation[ sUsed ];
        }

        cmdProcessSequence( cmd, pipeline, indirectCommandsLayout, pIndirectCommandsTokens, sUsed );
      }
    }

Valid Usage

- The `pipelineBindPoint` must be `VK_PIPELINE_BIND_POINT_GRAPHICS`

- `tokenCount` must be greater than `0` and less than or equal to `VkPhysicalDeviceDeviceGeneratedCommandsPropertiesNV`::`maxIndirectCommandsTokenCount`

- If `pTokens` contains an entry of `VK_INDIRECT_COMMANDS_TOKEN_TYPE_SHADER_GROUP_NV` it must be the first element of the array and there must be only a single element of such token type.

- If `pTokens` contains an entry of `VK_INDIRECT_COMMANDS_TOKEN_TYPE_STATE_FLAGS_NV` there must be only a single element of such token type.

- All state tokens in `pTokens` must occur prior work provoking tokens (`VK_INDIRECT_COMMANDS_TOKEN_TYPE_DRAW_NV`, `VK_INDIRECT_COMMANDS_TOKEN_TYPE_DRAW_INDEXED_NV`, `VK_INDIRECT_COMMANDS_TOKEN_TYPE_DRAW_TASKS_NV`).

- The content of `pTokens` must include one single work provoking token that is compatible with the `pipelineBindPoint`.

- `streamCount` must be greater than `0` and less or equal to `VkPhysicalDeviceDeviceGeneratedCommandsPropertiesNV`::`maxIndirectCommandsStreamCount`

- each element of `pStreamStrides` must be greater than `0`and less than or equal to `VkPhysicalDeviceDeviceGeneratedCommandsPropertiesNV`::`maxIndirectCommandsStreamStride`. Furthermore the alignment of each token input must be ensured.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_INDIRECT_COMMANDS_LAYOUT_CREATE_INFO_NV`

- `pNext` must be `NULL`

- `flags` must be a valid combination of VkIndirectCommandsLayoutUsageFlagBitsNV values

- `flags` must not be `0`

- `pipelineBindPoint` must be a valid VkPipelineBindPoint value

- `pTokens` must be a valid pointer to an array of `tokenCount` valid VkIndirectCommandsLayoutTokenNV structures

- `pStreamStrides` must be a valid pointer to an array of `streamCount` `uint32_t` values

- `tokenCount` must be greater than `0`

- `streamCount` must be greater than `0`

Bits which can be set in VkIndirectCommandsLayoutCreateInfoNV::`flags`, specifying usage hints of an indirect command layout, are:

    typedef enum VkIndirectCommandsLayoutUsageFlagBitsNV {
        VK_INDIRECT_COMMANDS_LAYOUT_USAGE_EXPLICIT_PREPROCESS_BIT_NV = 0x00000001,
        VK_INDIRECT_COMMANDS_LAYOUT_USAGE_INDEXED_SEQUENCES_BIT_NV = 0x00000002,
        VK_INDIRECT_COMMANDS_LAYOUT_USAGE_UNORDERED_SEQUENCES_BIT_NV = 0x00000004,
        VK_INDIRECT_COMMANDS_LAYOUT_USAGE_FLAG_BITS_MAX_ENUM_NV = 0x7FFFFFFF
    } VkIndirectCommandsLayoutUsageFlagBitsNV;

- `VK_INDIRECT_COMMANDS_LAYOUT_USAGE_EXPLICIT_PREPROCESS_BIT_NV` specifies that the layout is always used with the manual preprocessing step through calling vkCmdPreprocessGeneratedCommandsNV and executed by vkCmdExecuteGeneratedCommandsNV with `isPreprocessed` set to `VK_TRUE`.

- `VK_INDIRECT_COMMANDS_LAYOUT_USAGE_INDEXED_SEQUENCES_BIT_NV` specifies that the input data for the sequences is not implicitly indexed from 0..sequencesUsed but a user provided `VkBuffer` encoding the index is provided.

- `VK_INDIRECT_COMMANDS_LAYOUT_USAGE_UNORDERED_SEQUENCES_BIT_NV` specifies that the processing of sequences can happen at an implementation-dependent order, which is not: guaranteed to be coherent using the same input data.

    typedef VkFlags VkIndirectCommandsLayoutUsageFlagsNV;

`VkIndirectCommandsLayoutUsageFlagsNV` is a bitmask type for setting a mask of zero or more VkIndirectCommandsLayoutUsageFlagBitsNV.

Indirect command layouts are destroyed by:

    void vkDestroyIndirectCommandsLayoutNV(
        VkDevice                                    device,
        VkIndirectCommandsLayoutNV                  indirectCommandsLayout,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the logical device that destroys the layout.

- `indirectCommandsLayout` is the layout to destroy.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage

- All submitted commands that refer to `indirectCommandsLayout` must have completed execution

- If `VkAllocationCallbacks` were provided when `indirectCommandsLayout` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `indirectCommandsLayout` was created, `pAllocator` must be `NULL`

- The `VkPhysicalDeviceDeviceGeneratedCommandsFeaturesNV`→`deviceGeneratedCommands` feature must be enabled

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `indirectCommandsLayout` must be a valid VkIndirectCommandsLayoutNV handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `indirectCommandsLayout` must have been created, allocated, or retrieved from `device`

#### 30.1.2. Token Input Streams

The `VkIndirectCommandsStreamNV` structure specifies the input data for one or more tokens at processing time.

    typedef struct VkIndirectCommandsStreamNV {
        VkBuffer        buffer;
        VkDeviceSize    offset;
    } VkIndirectCommandsStreamNV;

- `buffer` specifies the VkBuffer storing the functional arguments for each sequence. These arguments can be written by the device.

- `offset` specified an offset into `buffer` where the arguments start.

Valid Usage

- The `buffer`’s usage flag must have the `VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT` bit set.

- The `offset` must be aligned to `VkPhysicalDeviceDeviceGeneratedCommandsPropertiesNV`::`minIndirectCommandsBufferOffsetAlignment`.

Valid Usage (Implicit)

- `buffer` must be a valid VkBuffer handle

The input streams can contain raw `uint32_t` values, existing indirect commands such as:

- VkDrawIndirectCommand

- VkDrawIndexedIndirectCommand

- VkDrawMeshTasksIndirectCommandNV

or additional commands as listed below. How the data is used is described in the next section.

The `VkBindShaderGroupIndirectCommandNV` structure specifies the input data for the `VK_INDIRECT_COMMANDS_TOKEN_TYPE_SHADER_GROUP_NV` token.

    typedef struct VkBindShaderGroupIndirectCommandNV {
        uint32_t    groupIndex;
    } VkBindShaderGroupIndirectCommandNV;

- `index` specifies which shader group of the current bound graphics pipeline is used.

Valid Usage

- The current bound graphics pipeline, as well as the pipelines it may reference, must have been created with `VK_PIPELINE_CREATE_INDIRECT_BINDABLE_BIT_NV`

- The `index` must be within range of the accessible shader groups of the current bound graphics pipeline. See vkCmdBindPipelineShaderGroupNV for further details.

The `VkBindIndexBufferIndirectCommandNV` structure specifies the input data for the `VK_INDIRECT_COMMANDS_TOKEN_TYPE_INDEX_BUFFER_NV` token.

    typedef struct VkBindIndexBufferIndirectCommandNV {
        VkDeviceAddress    bufferAddress;
        uint32_t           size;
        VkIndexType        indexType;
    } VkBindIndexBufferIndirectCommandNV;

- `bufferAddress` specifies a physical address of the VkBuffer used as index buffer.

- `size` is the byte size range which is available for this operation from the provided address.

- `indexType` is a VkIndexType value specifying how indices are treated. Instead of the Vulkan enum values, a custom `uint32_t` value can be mapped to an VkIndexType by specifying the `VkIndirectCommandsLayoutTokenNV`::`pIndexTypes` and `VkIndirectCommandsLayoutTokenNV`::`pIndexTypeValues` arrays.

Valid Usage

- The buffer’s usage flag from which the address was acquired must have the `VK_BUFFER_USAGE_INDEX_BUFFER_BIT` bit set.

- The `bufferAddress` must be aligned to the `indexType` used.

- Each element of the buffer from which the address was acquired and that is non-sparse must be bound completely and contiguously to a single `VkDeviceMemory` object

Valid Usage (Implicit)

- `indexType` must be a valid VkIndexType value

The `VkBindVertexBufferIndirectCommandNV` structure specifies the input data for the `VK_INDIRECT_COMMANDS_TOKEN_TYPE_VERTEX_BUFFER_NV` token.

    typedef struct VkBindVertexBufferIndirectCommandNV {
        VkDeviceAddress    bufferAddress;
        uint32_t           size;
        uint32_t           stride;
    } VkBindVertexBufferIndirectCommandNV;

- `bufferAddress` specifies a physical address of the VkBuffer used as vertex input binding.

- `size` is the byte size range which is available for this operation from the provided address.

- `stride` is the byte size stride for this vertex input binding as in `VkVertexInputBindingDescription`::`stride`. It is only used if `VkIndirectCommandsLayoutTokenNV`::`vertexDynamicStride` was set, otherwise the stride is inherited from the current bound graphics pipeline.

Valid Usage

- The buffer’s usage flag from which the address was acquired must have the `VK_BUFFER_USAGE_VERTEX_BUFFER_BIT` bit set.

- Each element of the buffer from which the address was acquired and that is non-sparse must be bound completely and contiguously to a single `VkDeviceMemory` object

The `VkSetStateFlagsIndirectCommandNV` structure specifies the input data for the `VK_INDIRECT_COMMANDS_TOKEN_TYPE_STATE_FLAGS_NV` token. Which state is changed depends on the VkIndirectStateFlagBitsNV specified at `VkIndirectCommandsLayoutNV` creation time.

    typedef struct VkSetStateFlagsIndirectCommandNV {
        uint32_t    data;
    } VkSetStateFlagsIndirectCommandNV;

- `data` encodes packed state that this command alters.

  - Bit `0`: If set represents `VK_FRONT_FACE_CLOCKWISE`, otherwise `VK_FRONT_FACE_COUNTER_CLOCKWISE`

A subset of the graphics pipeline state can be altered using indirect state flags:

    typedef enum VkIndirectStateFlagBitsNV {
        VK_INDIRECT_STATE_FLAG_FRONTFACE_BIT_NV = 0x00000001,
        VK_INDIRECT_STATE_FLAG_BITS_MAX_ENUM_NV = 0x7FFFFFFF
    } VkIndirectStateFlagBitsNV;

- `VK_INDIRECT_STATE_FLAG_FRONTFACE_BIT_NV` allows to toggle the VkFrontFace rasterization state for subsequent draw operations.

    typedef VkFlags VkIndirectStateFlagsNV;

`VkIndirectStateFlagsNV` is a bitmask type for setting a mask of zero or more VkIndirectStateFlagBitsNV.

#### 30.1.3. Tokenized Command Processing

The processing is in principle illustrated below:

    void cmdProcessSequence(cmd, pipeline, indirectCommandsLayout, pIndirectCommandsStreams, s)
    {
      for (t = 0; t < indirectCommandsLayout.tokenCount; t++)
      {
        uint32_t stream  = indirectCommandsLayout.pTokens[t].stream;
        uint32_t offset  = indirectCommandsLayout.pTokens[t].offset;
        uint32_t stride  = indirectCommandsLayout.pStreamStrides[stream];
        stream            = pIndirectCommandsStreams[stream];
        const void* input = stream.buffer.pointer( stream.offset + stride * s + offset )

        // further details later
        indirectCommandsLayout.pTokens[t].command (cmd, pipeline, input, s);
      }
    }

    void cmdProcessAllSequences(cmd, pipeline, indirectCommandsLayout, pIndirectCommandsStreams, sequencesCount)
    {
      for (s = 0; s < sequencesCount; s++)
      {
        cmdProcessSequence(cmd, pipeline, indirectCommandsLayout, pIndirectCommandsStreams, s);
      }
    }

The processing of each sequence is considered stateless, therefore all state changes must occur prior work provoking commands within the sequence. A single sequence is strictly targeting the VkPipelineBindPoint it was created with.

The primary input data for each token is provided through `VkBuffer` content at preprocessing using vkCmdPreprocessGeneratedCommandsNV or execution time using using vkCmdExecuteGeneratedCommandsNV, however some functional arguments, for example binding sets, are specified at layout creation time. The input size is different for each token.

Possible values of those elements of the VkIndirectCommandsLayoutCreateInfoNV::`pTokens` array which specify command tokens (other elements of the array specify command parameters) are:

    typedef enum VkIndirectCommandsTokenTypeNV {
        VK_INDIRECT_COMMANDS_TOKEN_TYPE_SHADER_GROUP_NV = 0,
        VK_INDIRECT_COMMANDS_TOKEN_TYPE_STATE_FLAGS_NV = 1,
        VK_INDIRECT_COMMANDS_TOKEN_TYPE_INDEX_BUFFER_NV = 2,
        VK_INDIRECT_COMMANDS_TOKEN_TYPE_VERTEX_BUFFER_NV = 3,
        VK_INDIRECT_COMMANDS_TOKEN_TYPE_PUSH_CONSTANT_NV = 4,
        VK_INDIRECT_COMMANDS_TOKEN_TYPE_DRAW_INDEXED_NV = 5,
        VK_INDIRECT_COMMANDS_TOKEN_TYPE_DRAW_NV = 6,
        VK_INDIRECT_COMMANDS_TOKEN_TYPE_DRAW_TASKS_NV = 7,
        VK_INDIRECT_COMMANDS_TOKEN_TYPE_MAX_ENUM_NV = 0x7FFFFFFF
    } VkIndirectCommandsTokenTypeNV;

Table 39. Supported indirect command tokens
Token type | Equivalent command
--- | ---
`VK_INDIRECT_COMMANDS_TOKEN_TYPE_SHADER_GROUP_NV` | vkCmdBindPipelineShaderGroupNV
`VK_INDIRECT_COMMANDS_TOKEN_TYPE_STATE_FLAGS_NV` | -
`VK_INDIRECT_COMMANDS_TOKEN_TYPE_INDEX_BUFFER_NV` | vkCmdBindIndexBuffer
`VK_INDIRECT_COMMANDS_TOKEN_TYPE_VERTEX_BUFFER_NV` | vkCmdBindVertexBuffers
`VK_INDIRECT_COMMANDS_TOKEN_TYPE_PUSH_CONSTANT_NV` | vkCmdPushConstants
`VK_INDIRECT_COMMANDS_TOKEN_TYPE_DRAW_INDEXED_NV` | vkCmdDrawIndexedIndirect
`VK_INDIRECT_COMMANDS_TOKEN_TYPE_DRAW_NV` | vkCmdDrawIndirect
`VK_INDIRECT_COMMANDS_TOKEN_TYPE_DRAW_TASKS_NV` | vkCmdDrawMeshTasksIndirectNV

The `VkIndirectCommandsLayoutTokenNV` structure specifies details to the function arguments that need to be known at layout creation time:

    typedef struct VkIndirectCommandsLayoutTokenNV {
        VkStructureType                  sType;
        const void*                      pNext;
        VkIndirectCommandsTokenTypeNV    tokenType;
        uint32_t                         stream;
        uint32_t                         offset;
        uint32_t                         vertexBindingUnit;
        VkBool32                         vertexDynamicStride;
        VkPipelineLayout                 pushconstantPipelineLayout;
        VkShaderStageFlags               pushconstantShaderStageFlags;
        uint32_t                         pushconstantOffset;
        uint32_t                         pushconstantSize;
        VkIndirectStateFlagsNV           indirectStateFlags;
        uint32_t                         indexTypeCount;
        const VkIndexType*               pIndexTypes;
        const uint32_t*                  pIndexTypeValues;
    } VkIndirectCommandsLayoutTokenNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `tokenType` specifies the token command type.

- `stream` is the index of the input stream that contains the token argument data.

- `offset` is a relative starting offset within the input stream memory for the token argument data.

- `vertexBindingUnit` is used for the vertex buffer binding command.

- `vertexDynamicStride` sets if the vertex buffer stride is provided by the binding command rather than the current bound graphics pipeline state.

- `pushconstantPipelineLayout` is the `VkPipelineLayout` used for the push constant command.

- `pushconstantShaderStageFlags` are the shader stage flags used for the push constant command.

- `pushconstantOffset` is the offset used for the push constant command.

- `pushconstantSize` is the size used for the push constant command.

- `indirectStateFlags` are the active states for the state flag command.

- `indexTypeCount` is the optional size of the `pIndexTypes` and `pIndexTypeValues` array pairings. If not zero, it allows to register a custom `uint32_t` value to be treated as specific `VkIndexType`.

- `pIndexTypes` is the used `VkIndexType` for the corresponding `uint32_t` value entry in pname::pIndexTypeValues.

Valid Usage

- `stream` must be smaller than `VkIndirectCommandsLayoutCreateInfoNV`::`streamCount`.

- `offset` must be less than or equal to `VkPhysicalDeviceDeviceGeneratedCommandsPropertiesNV`::`maxIndirectCommandsTokenOffset`.

- `vertexBindingUnit` must stay within device supported limits for the appropriate commands.

- `pushconstantOffset` must stay within device supported limits for the appropriate commands.

- `pushconstantSize` must stay within device supported limits for the appropriate commands.

- `indirectStateFlags` must not be ´0´.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_INDIRECT_COMMANDS_LAYOUT_TOKEN_NV`

- `pNext` must be `NULL`

- `tokenType` must be a valid VkIndirectCommandsTokenTypeNV value

- If `pushconstantPipelineLayout` is not VK_NULL_HANDLE, `pushconstantPipelineLayout` must be a valid VkPipelineLayout handle

- `pushconstantShaderStageFlags` must be a valid combination of VkShaderStageFlagBits values

- `indirectStateFlags` must be a valid combination of VkIndirectStateFlagBitsNV values

- If `indexTypeCount` is not `0`, `pIndexTypes` must be a valid pointer to an array of `indexTypeCount` valid VkIndexType values

- If `indexTypeCount` is not `0`, `pIndexTypeValues` must be a valid pointer to an array of `indexTypeCount` `uint32_t` values

The following code provides detailed information on how an individual sequence is processed. For valid usage, all restrictions from the regular commands apply.

    void cmdProcessSequence(cmd, pipeline, indirectCommandsLayout, pIndirectCommandsStreams, s)
    {
      for (uint32_t t = 0; t < indirectCommandsLayout.tokenCount; t++){
        token = indirectCommandsLayout.pTokens[t];

        uint32_t stride   = indirectCommandsLayout.pStreamStrides[token.stream];
        stream            = pIndirectCommandsStreams[token.stream];
        uint32_t offset   = stream.offset + stride * s + token.offset;
        const void* input = stream.buffer.pointer( offset )

        switch(input.type){
        VK_INDIRECT_COMMANDS_TOKEN_TYPE_SHADER_GROUP_NV:
          VkBindShaderGroupIndirectCommandNV* bind = input;

          vkCmdBindPipelineShaderGroupNV(cmd, indirectCommandsLayout.pipelineBindPoint,
            pipeline, bind->groupIndex);
        break;

        VK_INDIRECT_COMMANDS_TOKEN_TYPE_STATE_FLAGS_NV:
          VkSetStateFlagsIndirectCommandNV* state = input;

          if (token.indirectStateFlags & VK_INDIRECT_STATE_FLAG_FRONTFACE_BIT_NV){
            if (state.data & (1 << 0)){
              set VK_FRONT_FACE_CLOCKWISE;
            } else {
              set VK_FRONT_FACE_COUNTER_CLOCKWISE;
            }
          }
        break;

        VK_INDIRECT_COMMANDS_TOKEN_TYPE_PUSH_CONSTANT_NV:
          uint32_t* data = input;

          vkCmdPushConstants(cmd,
            token.pushconstantPipelineLayout
            token.pushconstantStageFlags,
            token.pushconstantOffset,
            token.pushconstantSize, data);
        break;

        VK_INDIRECT_COMMANDS_TOKEN_TYPE_INDEX_BUFFER_NV:
          VkBindIndexBufferIndirectCommandNV* data = input;

          // the indexType may optionally be remapped
          // from a custom uint32_t value, via
          // VkIndirectCommandsLayoutTokenNV::pIndexTypeValues

          vkCmdBindIndexBuffer(cmd,
            deriveBuffer(data->bufferAddress),
            deriveOffset(data->bufferAddress),
            data->indexType);
        break;

        VK_INDIRECT_COMMANDS_TOKEN_TYPE_VERTEX_BUFFER_NV:
          VkBindVertexBufferIndirectCommandNV* data = input;

          // if token.vertexDynamicStride is VK_TRUE
          // then the stride for this binding is set
          // using data->stride as well

          vkCmdBindVertexBuffers(cmd,
            token.vertexBindingUnit, 1,
            &deriveBuffer(data->bufferAddress),
            &deriveOffset(data->bufferAddress));
        break;

        VK_INDIRECT_COMMANDS_TOKEN_TYPE_DRAW_INDEXED_NV:
          vkCmdDrawIndexedIndirect(cmd,
            stream.buffer, offset, 1, 0);
        break;

        VK_INDIRECT_COMMANDS_TOKEN_TYPE_DRAW_NV:
          vkCmdDrawIndirect(cmd,
            stream.buffer,
            offset, 1, 0);
        break;

        // only available if VK_NV_mesh_shader is supported
        VK_INDIRECT_COMMANDS_TOKEN_TYPE_DISPATCH_NV:
          vkCmdDrawMeshTasksIndirectNV(cmd,
            stream.buffer, offset, 1, 0);
        break;
        }
      }
    }

### 30.2. Indirect Commands Generation And Execution

The generation of commands on the device requires a `preprocess` buffer. To retrieve the memory size and alignment requirements of a particular execution state call:

    void vkGetGeneratedCommandsMemoryRequirementsNV(
        VkDevice                                    device,
        const VkGeneratedCommandsMemoryRequirementsInfoNV* pInfo,
        VkMemoryRequirements2*                      pMemoryRequirements);

- `device` is the logical device that owns the buffer.

- `pInfo` is a pointer to an instance of the `VkGeneratedCommandsMemoryRequirementsInfoNV` structure containing parameters required for the memory requirements query.

- `pMemoryRequirements` points to an instance of the VkMemoryRequirements2 structure in which the memory requirements of the buffer object are returned.

Valid Usage

- The `VkPhysicalDeviceDeviceGeneratedCommandsFeaturesNV`→`deviceGeneratedCommands` feature must be enabled

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pInfo` must be a valid pointer to a valid VkGeneratedCommandsMemoryRequirementsInfoNV structure

- `pMemoryRequirements` must be a valid pointer to a VkMemoryRequirements2 structure

    typedef struct VkGeneratedCommandsMemoryRequirementsInfoNV {
        VkStructureType               sType;
        const void*                   pNext;
        VkPipelineBindPoint           pipelineBindPoint;
        VkPipeline                    pipeline;
        VkIndirectCommandsLayoutNV    indirectCommandsLayout;
        uint32_t                      maxSequencesCount;
    } VkGeneratedCommandsMemoryRequirementsInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `pipelineBindPoint` is the VkPipelineBindPoint of the `pipeline` that this buffer memory is intended to be used with during the execution.

- `pipeline` is the slink::VkPipeline that this buffer memory is intended to be used with during the execution.

- `indirectCommandsLayout` is the VkIndirectCommandsLayoutNV that this buffer memory is intended to be used with.

- `maxSequencesCount` is the maximum number of sequences that this buffer memory in combination with the other state provided can be used with.

Valid Usage

- `maxSequencesCount` must be less or equal to VkPhysicalDeviceDeviceGeneratedCommandsPropertiesNV::`maxIndirectSequenceCount`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_GENERATED_COMMANDS_MEMORY_REQUIREMENTS_INFO_NV`

- `pNext` must be `NULL`

The actual generation of commands as well as their execution on the device is handled as single action with:

    void vkCmdExecuteGeneratedCommandsNV(
        VkCommandBuffer                             commandBuffer,
        VkBool32                                    isPreprocessed,
        const VkGeneratedCommandsInfoNV*            pGeneratedCommandsInfo);

- `commandBuffer` is the command buffer into which the command is recorded.

- `isPreprocessed` represents whether the input data has already been preprocessed on the device. If it is `VK_FALSE` this command will implicitly trigger the preprocessing step, otherwise not.

- `pGeneratedCommandsInfo` is a pointer to an instance of the VkGeneratedCommandsInfoNV structure containing parameters affecting the generation of commands.

Valid Usage

- If `isPreprocessed` is `VK_TRUE` then vkCmdPreprocessGeneratedCommandsNV must have already been executed on the device, using the same `pGeneratedCommandsInfo` content as well as the content of the input buffers it references (all except VkGeneratedCommandsInfoNV::`preprocessBuffer`). Furthermore `pGeneratedCommandsInfo``s `indirectCommandsLayout` must have been created with the `VK_INDIRECT_COMMANDS_LAYOUT_USAGE_EXPLICIT_PREPROCESS_BIT_NV` bit set.

- `VkGeneratedCommandsInfoNV`::`pipeline` must match the current bound pipeline at `VkGeneratedCommandsInfoNV`::`pipelineBindPoint`.

- Transform feedback must not be active.

- The `VkPhysicalDeviceDeviceGeneratedCommandsFeaturesNV`→`deviceGeneratedCommands` feature must be enabled

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pGeneratedCommandsInfo` must be a valid pointer to a valid VkGeneratedCommandsInfoNV structure

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

- This command must only be called inside of a render pass instance

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Inside | Graphics Compute |

    typedef struct VkGeneratedCommandsInfoNV {
        VkStructureType                      sType;
        const void*                          pNext;
        VkPipelineBindPoint                  pipelineBindPoint;
        VkPipeline                           pipeline;
        VkIndirectCommandsLayoutNV           indirectCommandsLayout;
        uint32_t                             streamCount;
        const VkIndirectCommandsStreamNV*    pStreams;
        uint32_t                             sequencesCount;
        VkBuffer                             preprocessBuffer;
        VkDeviceSize                         preprocessOffset;
        VkDeviceSize                         preprocessSize;
        VkBuffer                             sequencesCountBuffer;
        VkDeviceSize                         sequencesCountOffset;
        VkBuffer                             sequencesIndexBuffer;
        VkDeviceSize                         sequencesIndexOffset;
    } VkGeneratedCommandsInfoNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `pipelineBindPoint` is the VkPipelineBindPoint used for the `pipeline`.

- `pipeline` is the VkPipeline used in the generation and execution process.

- `indirectCommandsLayout` is the VkIndirectCommandsLayoutNV that provides the command sequence to generate.

- `streamCount` defines the number of input streams

- `pStreams` provides an array of VkIndirectCommandsStreamNV that provide the input data for the tokens used in `indirectCommandsLayout`.

- `sequencesCount` is the maximum number of sequences to reserve. If `sequencesCountBuffer` is VK_NULL_HANDLE, this is also the actual number of sequences generated.

- `preprocessBuffer` is the VkBuffer that is used for preprocessing the input data for execution. If this structure is used with vkCmdExecuteGeneratedCommandsNV with its `isPreprocessed` set to `VK_TRUE`, then the preprocessing step is skipped and data is only read from this buffer.

- `preprocessOffset` is the byte offset into `preprocessBuffer` where the preprocessed data is stored.

- `preprocessSize` is the maximum byte size within the `preprocessBuffer` after the `preprocessOffset` that is available for preprocessing.

- `sequencesCountBuffer` is a `VkBuffer` in which the actual number of sequences is provided as single `uint32_t` value.

- `sequencesCountOffset` is the byte offset into `sequencesCountBuffer` where the count value is stored.

- `sequencesIndexBuffer` is a `VkBuffer` that encodes the used sequence indices as `uint32_t` array.

- `sequencesIndexOffset` is the byte offset into `sequencesIndexBuffer` where the index values start.

Valid Usage

- The provided `pipeline` must match the pipeline bound at execution time.

- If the `indirectCommandsLayout` uses a token of `VK_INDIRECT_COMMANDS_TOKEN_TYPE_SHADER_GROUP_NV`, then the `pipeline` must have been created with multiple shader groups.

- If the `indirectCommandsLayout` uses a token of `VK_INDIRECT_COMMANDS_TOKEN_TYPE_SHADER_GROUP_NV`, then the `pipeline` must have been created with `VK_PIPELINE_CREATE_INDIRECT_BINDABLE_BIT_NV` set in `VkGraphicsPipelineCreateInfo`::`flags`.

- If the `indirectCommandsLayout` uses a token of `VK_INDIRECT_COMMANDS_TOKEN_TYPE_PUSH_CONSTANT_NV`, then the `pipeline``s `VkPipelineLayout` must match the VkIndirectCommandsLayoutTokenNV::`pushconstantPipelineLayout`.

- `streamCount` must match the `indirectCommandsLayout`’s `streamCount`

- `sequencesCount` must be less or equal to VkPhysicalDeviceDeviceGeneratedCommandsPropertiesNV::`maxIndirectSequenceCount` and VkGeneratedCommandsMemoryRequirementsInfoNV::`maxSequencesCount` that was used to determine the `preprocessSize`.

- `preprocessBuffer` must have the `VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT` bit set in its usage flag.

- `preprocessOffset` must be aligned to VkPhysicalDeviceDeviceGeneratedCommandsPropertiesNV::`minIndirectCommandsBufferOffsetAlignment`

- `preprocessSize` must be at least equal to the memory requirement`s size returned by vkGetGeneratedCommandsMemoryRequirementsNV using the matching inputs (`indirectCommandsLayout`, …​) as within this structure.

- `sequencesCountBuffer` can be set if the actual used count of sequences is sourced from the provided buffer. In that case the `sequencesCount` serves as upper bound.

- If `sequencesCountBuffer` is used, its usage flag must have the `VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT` bit set

- If `sequencesCountBuffer` is used, `sequencesCountOffset` must be aligned to `VkPhysicalDeviceDeviceGeneratedCommandsPropertiesNV`::`minSequencesCountBufferOffsetAlignment`

- `sequencesIndexBuffer` must be set if `indirectCommandsLayout`’s `VK_INDIRECT_COMMANDS_LAYOUT_USAGE_INDEXED_SEQUENCES_BIT_NV` is set, otherwise it must be VK_NULL_HANDLE.

- If `sequencesIndexBuffer` is used, its usage flag must have the `VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT` bit set

- If `sequencesIndexBuffer` is used, `sequencesIndexOffset` must be aligned to `VkPhysicalDeviceDeviceGeneratedCommandsPropertiesNV`::`minSequencesIndexBufferOffsetAlignment`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_GENERATED_COMMANDS_INFO_NV`

- `pNext` must be `NULL`

- `pipelineBindPoint` must be a valid VkPipelineBindPoint value

- `pipeline` must be a valid VkPipeline handle

- `indirectCommandsLayout` must be a valid VkIndirectCommandsLayoutNV handle

- `pStreams` must be a valid pointer to an array of `streamCount` valid VkIndirectCommandsStreamNV structures

- `preprocessBuffer` must be a valid VkBuffer handle

- If `sequencesCountBuffer` is not VK_NULL_HANDLE, `sequencesCountBuffer` must be a valid VkBuffer handle

- If `sequencesIndexBuffer` is not VK_NULL_HANDLE, `sequencesIndexBuffer` must be a valid VkBuffer handle

- `streamCount` must be greater than `0`

- Each of `indirectCommandsLayout`, `pipeline`, `preprocessBuffer`, `sequencesCountBuffer`, and `sequencesIndexBuffer` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

Referencing the functions defined in Indirect Commands Layout, `vkCmdExecuteGeneratedCommandsNV` behaves as:

    uint32_t sequencesCount = sequencesCountBuffer ?
          min(maxSequencesCount, sequencesCountBuffer.load_uint32(sequencesCountOffset) :
          maxSequencesCount;

    cmdProcessAllSequences(commandBuffer, pipeline,
                           indirectCommandsLayout, pIndirectCommandsStreams,
                           sequencesCount,
                           sequencesIndexBuffer, sequencesIndexOffset);

    // The stateful commands within indirectCommandsLayout will not
    // affect the state of subsequent commands in the target
    // command buffer (cmd)

| Note It is important to note that all state related to the `pipelineBindPoint` used is considered undefined after this command.

Commands can be preprocessed prior execution using the following command:

    void vkCmdPreprocessGeneratedCommandsNV(
        VkCommandBuffer                             commandBuffer,
        const VkGeneratedCommandsInfoNV*            pGeneratedCommandsInfo);

- `commandBuffer` is the command buffer which does the preprocessing.

- `pGeneratedCommandsInfo` is a pointer to an instance of the VkGeneratedCommandsInfoNV structure containing parameters affecting the preprocessing step.

Valid Usage

- `pGeneratedCommandsInfo``s `indirectCommandsLayout` must have been created with the `VK_INDIRECT_COMMANDS_LAYOUT_USAGE_EXPLICIT_PREPROCESS_BIT_NV` bit set.

- The `VkPhysicalDeviceDeviceGeneratedCommandsFeaturesNV`→`deviceGeneratedCommands` feature must be enabled

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pGeneratedCommandsInfo` must be a valid pointer to a valid VkGeneratedCommandsInfoNV structure

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

- This command must only be called outside of a render pass instance

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Graphics Compute |

## 31. Sparse Resources

As documented in Resource Memory Association, `VkBuffer` and `VkImage` resources in Vulkan must be bound completely and contiguously to a single `VkDeviceMemory` object. This binding must be done before the resource is used, and the binding is immutable for the lifetime of the resource.

Sparse resources relax these restrictions and provide these additional features:

- Sparse resources can be bound non-contiguously to one or more `VkDeviceMemory` allocations.

- Sparse resources can be re-bound to different memory allocations over the lifetime of the resource.

- Sparse resources can have descriptors generated and used orthogonally with memory binding commands.

### 31.1. Sparse Resource Features

Sparse resources have several features that must be enabled explicitly at resource creation time. The features are enabled by including bits in the `flags` parameter of VkImageCreateInfo or VkBufferCreateInfo. Each feature also has one or more corresponding feature enables specified in VkPhysicalDeviceFeatures.

- Sparse binding is the base feature, and provides the following capabilities:

  - Resources can be bound at some defined (sparse block) granularity.

  - The entire resource must be bound to memory before use regardless of regions actually accessed.

  - No specific mapping of image region to memory offset is defined, i.e. the location that each texel corresponds to in memory is implementation-dependent.

  - Sparse buffers have a well-defined mapping of buffer range to memory range, where an offset into a range of the buffer that is bound to a single contiguous range of memory corresponds to an identical offset within that range of memory.

  - Requested via the `VK_IMAGE_CREATE_SPARSE_BINDING_BIT` and `VK_BUFFER_CREATE_SPARSE_BINDING_BIT` bits.

  - A sparse image created using `VK_IMAGE_CREATE_SPARSE_BINDING_BIT` (but not `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`) supports all formats that non-sparse usage supports, and supports both `VK_IMAGE_TILING_OPTIMAL` and `VK_IMAGE_TILING_LINEAR` tiling.

- Sparse Residency builds on (and requires) the `sparseBinding` feature. It includes the following capabilities:

  - Resources do not have to be completely bound to memory before use on the device.

  - Images have a prescribed sparse image block layout, allowing specific rectangular regions of the image to be bound to specific offsets in memory allocations.

  - Consistency of access to unbound regions of the resource is defined by the absence or presence of `VkPhysicalDeviceSparseProperties`::`residencyNonResidentStrict`. If this property is present, accesses to unbound regions of the resource are well defined and behave as if the data bound is populated with all zeros; writes are discarded. When this property is absent, accesses are considered safe, but reads will return undefined values.

  - Requested via the `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT` and `VK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT` bits.

  - Sparse residency support is advertised on a finer grain via the following features:

    - `sparseResidencyBuffer`: Support for creating `VkBuffer` objects with the `VK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT`.

    - `sparseResidencyImage2D`: Support for creating 2D single-sampled `VkImage` objects with `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`.

    - `sparseResidencyImage3D`: Support for creating 3D `VkImage` objects with `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`.

    - `sparseResidency2Samples`: Support for creating 2D `VkImage` objects with 2 samples and `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`.

    - `sparseResidency4Samples`: Support for creating 2D `VkImage` objects with 4 samples and `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`.

    - `sparseResidency8Samples`: Support for creating 2D `VkImage` objects with 8 samples and `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`.

    - `sparseResidency16Samples`: Support for creating 2D `VkImage` objects with 16 samples and `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`.

    Implementations supporting `sparseResidencyImage2D` are only required to support sparse 2D, single-sampled images. Support for sparse 3D and MSAA images is optional and can be enabled via `sparseResidencyImage3D`, `sparseResidency2Samples`, `sparseResidency4Samples`, `sparseResidency8Samples`, and `sparseResidency16Samples`.

  - A sparse image created using `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT` supports all non-compressed color formats with power-of-two element size that non-sparse usage supports. Additional formats may also be supported and can be queried via vkGetPhysicalDeviceSparseImageFormatProperties. `VK_IMAGE_TILING_LINEAR` tiling is not supported.

- Sparse aliasing provides the following capability that can be enabled per resource:

  Allows physical memory ranges to be shared between multiple locations in the same sparse resource or between multiple sparse resources, with each binding of a memory location observing a consistent interpretation of the memory contents.

  See Sparse Memory Aliasing for more information.

### 31.2. Sparse Buffers and Fully-Resident Images

Both `VkBuffer` and `VkImage` objects created with the `VK_IMAGE_CREATE_SPARSE_BINDING_BIT` or `VK_BUFFER_CREATE_SPARSE_BINDING_BIT` bits can be thought of as a linear region of address space. In the `VkImage` case if `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT` is not used, this linear region is entirely opaque, meaning that there is no application-visible mapping between texel location and memory offset.

Unless `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT` or `VK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT` are also used, the entire resource must be bound to one or more `VkDeviceMemory` objects before use.

#### 31.2.1. Sparse Buffer and Fully-Resident Image Block Size

The sparse block size in bytes for sparse buffers and fully-resident images is reported as `VkMemoryRequirements`::`alignment`. `alignment` represents both the memory alignment requirement and the binding granularity (in bytes) for sparse resources.

### 31.3. Sparse Partially-Resident Buffers

`VkBuffer` objects created with the `VK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT` bit allow the buffer to be made only partially resident. Partially resident `VkBuffer` objects are allocated and bound identically to `VkBuffer` objects using only the `VK_BUFFER_CREATE_SPARSE_BINDING_BIT` feature. The only difference is the ability for some regions of the buffer to be unbound during device use.

### 31.4. Sparse Partially-Resident Images

`VkImage` objects created with the `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT` bit allow specific rectangular regions of the image called sparse image blocks to be bound to specific ranges of memory. This allows the application to manage residency at either image subresource or sparse image block granularity. Each image subresource (outside of the mip tail) starts on a sparse block boundary and has dimensions that are integer multiples of the corresponding dimensions of the sparse image block.

| Note Applications can use these types of images to control LOD based on total memory consumption. If memory pressure becomes an issue the application can unbind and disable specific mipmap levels of images without having to recreate resources or modify texel data of unaffected levels. The application can also use this functionality to access subregions of the image in a “megatexture” fashion. The application can create a large image and only populate the region of the image that is currently being used in the scene.

#### 31.4.1. Accessing Unbound Regions

The following member of `VkPhysicalDeviceSparseProperties` affects how data in unbound regions of sparse resources are handled by the implementation:

- `residencyNonResidentStrict`

If this property is not present, reads of unbound regions of the image will return undefined values. Both reads and writes are still considered safe and will not affect other resources or populated regions of the image.

If this property is present, all reads of unbound regions of the image will behave as if the region was bound to memory populated with all zeros; writes will be discarded.

Formatted accesses to unbound memory may still alter some component values in the natural way for those accesses, e.g. substituting a value of one for alpha in formats that do not have an alpha component.

Example: Reading the alpha component of an unbacked `VK_FORMAT_R8_UNORM` image will return a value of 1.0f.

See Physical Device Enumeration for instructions for retrieving physical device properties.

Implementor’s Note

For implementations that cannot natively handle access to unbound regions of a resource, the implementation may allocate and bind memory to the unbound regions. Reads and writes to unbound regions will access the implementation-managed memory instead.

Given that the values resulting from reads of unbound regions are undefined in this scenario, implementations may use the same physical memory for all unbound regions of multiple resources within the same process.

#### 31.4.2. Mip Tail Regions

Sparse images created using `VK_IMAGE_CREATE_SPARSE_BINDING_BIT` (without also using `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`) have no specific mapping of image region or image subresource to memory offset defined, so the entire image can be thought of as a linear opaque address region. However, images created with `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT` do have a prescribed sparse image block layout, and hence each image subresource must start on a sparse block boundary. Within each array layer, the set of mip levels that have a smaller size than the sparse block size in bytes are grouped together into a mip tail region.

If the `VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BIT` flag is present in the `flags` member of `VkSparseImageFormatProperties`, for the image’s `format`, then any mip level which has dimensions that are not integer multiples of the corresponding dimensions of the sparse image block, and all subsequent mip levels, are also included in the mip tail region.

The following member of `VkPhysicalDeviceSparseProperties` may affect how the implementation places mip levels in the mip tail region:

- `residencyAlignedMipSize`

Each mip tail region is bound to memory as an opaque region (i.e. must be bound using a VkSparseImageOpaqueMemoryBindInfo structure) and may be of a size greater than or equal to the sparse block size in bytes. This size is guaranteed to be an integer multiple of the sparse block size in bytes.

An implementation may choose to allow each array-layer’s mip tail region to be bound to memory independently or require that all array-layer’s mip tail regions be treated as one. This is dictated by `VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT` in `VkSparseImageMemoryRequirements`::`flags`.

The following diagrams depict how `VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BIT` and `VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT` alter memory usage and requirements.

Figure 19. Sparse Image

In the absence of `VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BIT` and `VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT`, each array layer contains a mip tail region containing texel data for all mip levels smaller than the sparse image block in any dimension.

Mip levels that are as large or larger than a sparse image block in all dimensions can be bound individually. Right-edges and bottom-edges of each level are allowed to have partially used sparse blocks. Any bound partially-used-sparse-blocks must still have their full sparse block size in bytes allocated in memory.

Figure 20. Sparse Image with Single Mip Tail

When `VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT` is present all array layers will share a single mip tail region.

Figure 21. Sparse Image with Aligned Mip Size

| Note The mip tail regions are presented here in 2D arrays simply for figure size reasons. Each mip tail is logically a single array of sparse blocks with an implementation-dependent mapping of texels or compressed texel blocks to sparse blocks.

When `VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BIT` is present the first mip level that would contain partially used sparse blocks begins the mip tail region. This level and all subsequent levels are placed in the mip tail. Only the first N mip levels whose dimensions are an exact multiple of the sparse image block dimensions can be bound and unbound on a sparse block basis.

Figure 22. Sparse Image with Aligned Mip Size and Single Mip Tail

| Note The mip tail region is presented here in a 2D array simply for figure size reasons. It is logically a single array of sparse blocks with an implementation-dependent mapping of texels or compressed texel blocks to sparse blocks.

When both `VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BIT` and `VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT` are present the constraints from each of these flags are in effect.

#### 31.4.3. Standard Sparse Image Block Shapes

Standard sparse image block shapes define a standard set of dimensions for sparse image blocks that depend on the format of the image. Layout of texels or compressed texel blocks within a sparse image block is implementation dependent. All currently defined standard sparse image block shapes are 64 KB in size.

For block-compressed formats (e.g. `VK_FORMAT_BC5_UNORM_BLOCK`), the texel size is the size of the compressed texel block (e.g. 128-bit for `BC5`) thus the dimensions of the standard sparse image block shapes apply in terms of compressed texel blocks.

| Note For block-compressed formats, the dimensions of a sparse image block in terms of texels can be calculated by multiplying the sparse image block dimensions by the compressed texel block dimensions.

Table 40. Standard Sparse Image Block Shapes (Single Sample)
TEXEL SIZE (bits) | Block Shape (2D) | Block Shape (3D)
--- | --- | ---
8-Bit | 256 × 256 × 1 | 64 × 32 × 32
16-Bit | 256 × 128 × 1 | 32 × 32 × 32
32-Bit | 128 × 128 × 1 | 32 × 32 × 16
64-Bit | 128 × 64 × 1 | 32 × 16 × 16
128-Bit | 64 × 64 × 1 | 16 × 16 × 16

Table 41. Standard Sparse Image Block Shapes (MSAA)
TEXEL SIZE (bits) | Block Shape (2X) | Block Shape (4X) | Block Shape (8X) | Block Shape (16X)
--- | --- | --- | --- | ---
8-Bit | 128 × 256 × 1 | 128 × 128 × 1 | 64 × 128 × 1 | 64 × 64 × 1
16-Bit | 128 × 128 × 1 | 128 × 64 × 1 | 64 × 64 × 1 | 64 × 32 × 1
32-Bit | 64 × 128 × 1 | 64 × 64 × 1 | 32 × 64 × 1 | 32 × 32 × 1
64-Bit | 64 × 64 × 1 | 64 × 32 × 1 | 32 × 32 × 1 | 32 × 16 × 1
128-Bit | 32 × 64 × 1 | 32 × 32 × 1 | 16 × 32 × 1 | 16 × 16 × 1

Implementations that support the standard sparse image block shape for all formats listed in the Standard Sparse Image Block Shapes (Single Sample) and Standard Sparse Image Block Shapes (MSAA) tables may advertise the following `VkPhysicalDeviceSparseProperties`:

- `residencyStandard2DBlockShape`

- `residencyStandard2DMultisampleBlockShape`

- `residencyStandard3DBlockShape`

Reporting each of these features does not imply that all possible image types are supported as sparse. Instead, this indicates that no supported sparse image of the corresponding type will use custom sparse image block dimensions for any formats that have a corresponding standard sparse image block shape.

#### 31.4.4. Custom Sparse Image Block Shapes

An implementation that does not support a standard image block shape for a particular sparse partially-resident image may choose to support a custom sparse image block shape for it instead. The dimensions of such a custom sparse image block shape are reported in `VkSparseImageFormatProperties`::`imageGranularity`. As with standard sparse image block shapes, the size in bytes of the custom sparse image block shape will be reported in `VkMemoryRequirements`::`alignment`.

Custom sparse image block dimensions are reported through `vkGetPhysicalDeviceSparseImageFormatProperties` and `vkGetImageSparseMemoryRequirements`.

An implementation must not support both the standard sparse image block shape and a custom sparse image block shape for the same image. The standard sparse image block shape must be used if it is supported.

#### 31.4.5. Multiple Aspects

Partially resident images are allowed to report separate sparse properties for different aspects of the image. One example is for depth/stencil images where the implementation separates the depth and stencil data into separate planes. Another reason for multiple aspects is to allow the application to manage memory allocation for implementation-private metadata associated with the image. See the figure below:

Figure 23. Multiple Aspect Sparse Image

| Note The mip tail regions are presented here in 2D arrays simply for figure size reasons. Each mip tail is logically a single array of sparse blocks with an implementation-dependent mapping of texels or compressed texel blocks to sparse blocks.

In the figure above the depth, stencil, and metadata aspects all have unique sparse properties. The per-texel stencil data is ¼ the size of the depth data, hence the stencil sparse blocks include 4 × the number of texels. The sparse block size in bytes for all of the aspects is identical and defined by `VkMemoryRequirements`::`alignment`.

##### Metadata

The metadata aspect of an image has the following constraints:

- All metadata is reported in the mip tail region of the metadata aspect.

- All metadata must be bound prior to device use of the sparse image.

### 31.5. Sparse Memory Aliasing

By default sparse resources have the same aliasing rules as non-sparse resources. See Memory Aliasing for more information.

`VkDevice` objects that have the sparseResidencyAliased feature enabled are able to use the `VK_BUFFER_CREATE_SPARSE_ALIASED_BIT` and `VK_IMAGE_CREATE_SPARSE_ALIASED_BIT` flags for resource creation. These flags allow resources to access physical memory bound into multiple locations within one or more sparse resources in a data consistent fashion. This means that reading physical memory from multiple aliased locations will return the same value.

Care must be taken when performing a write operation to aliased physical memory. Memory dependencies must be used to separate writes to one alias from reads or writes to another alias. Writes to aliased memory that are not properly guarded against accesses to different aliases will have undefined results for all accesses to the aliased memory.

Applications that wish to make use of data consistent sparse memory aliasing must abide by the following guidelines:

- All sparse resources that are bound to aliased physical memory must be created with the `VK_BUFFER_CREATE_SPARSE_ALIASED_BIT` / `VK_IMAGE_CREATE_SPARSE_ALIASED_BIT` flag.

- All resources that access aliased physical memory must interpret the memory in the same way. This implies the following:

  - Buffers and images cannot alias the same physical memory in a data consistent fashion. The physical memory ranges must be used exclusively by buffers or used exclusively by images for data consistency to be guaranteed.

  - Memory in sparse image mip tail regions cannot access aliased memory in a data consistent fashion.

  - Sparse images that alias the same physical memory must have compatible formats and be using the same sparse image block shape in order to access aliased memory in a data consistent fashion.

Failure to follow any of the above guidelines will require the application to abide by the normal, non-sparse resource aliasing rules. In this case memory cannot be accessed in a data consistent fashion.

| Note Enabling sparse resource memory aliasing can be a way to lower physical memory use, but it may reduce performance on some implementations. An application developer can test on their target HW and balance the memory / performance trade-offs measured.

### 31.6. Sparse Resource Implementation Guidelines

This section is Informative. It is included to aid in implementors’ understanding of sparse resources.

Device Virtual Address

The basic `sparseBinding` feature allows the resource to reserve its own device virtual address range at resource creation time rather than relying on a bind operation to set this. Without any other creation flags, no other constraints are relaxed compared to normal resources. All pages must be bound to physical memory before the device accesses the resource.

The sparse residency features allow sparse resources to be used even when not all pages are bound to memory. Implementations that support access to unbound pages without causing a fault may support `residencyNonResidentStrict`.

Not faulting on access to unbound pages is not enough to support `residencyNonResidentStrict`. An implementation must also guarantee that reads after writes to unbound regions of the resource always return data for the read as if the memory contains zeros. Depending on any caching hierarchy of the implementation this may not always be possible.

Any implementation that does not fault, but does not guarantee correct read values must not support `residencyNonResidentStrict`.

Any implementation that cannot access unbound pages without causing a fault will require the implementation to bind the entire device virtual address range to physical memory. Any pages that the application does not bind to memory may be bound to one (or more) “dummy” physical page(s) allocated by the implementation. Given the following properties:

- A process must not access memory from another process

- Reads return undefined values

It is sufficient for each host process to allocate these dummy pages and use them for all resources in that process. Implementations may allocate more often (per instance, per device, or per resource).

Binding Memory

The byte size reported in `VkMemoryRequirements`::`size` must be greater than or equal to the amount of physical memory required to fully populate the resource. Some implementations require “holes” in the device virtual address range that are never accessed. These holes may be included in the `size` reported for the resource.

Including or not including the device virtual address holes in the resource size will alter how the implementation provides support for `VkSparseImageOpaqueMemoryBindInfo`. This operation must be supported for all sparse images, even ones created with `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`.

| editing-note @ntrevett suggested expanding the NOTE tag below to encompass everything from “The cost is…​” in the first bullet point through the current note. TBD.

- If the holes are included in the size, this bind function becomes very easy. In most cases the `resourceOffset` is simply a device virtual address offset and the implementation can easily determine what device virtual address to bind. The cost is that the application may allocate more physical memory for the resource than it needs.

- If the holes are not included in the size, the application can allocate less physical memory than otherwise for the resource. However, in this case the implementation must account for the holes when mapping `resourceOffset` to the actual device virtual address intended to be mapped.

| Note If the application always uses `VkSparseImageMemoryBindInfo` to bind memory for the non-tail mip levels, any holes that are present in the resource size may never be bound. Since `VkSparseImageMemoryBindInfo` uses texel locations to determine which device virtual addresses to bind, it is impossible to bind device virtual address holes with this operation.

Binding Metadata Memory

All metadata for sparse images have their own sparse properties and are embedded in the mip tail region for said properties. See the Multiaspect section for details.

Given that metadata is in a mip tail region, and the mip tail region must be reported as contiguous (either globally or per-array-layer), some implementations will have to resort to complicated offset → device virtual address mapping for handling `VkSparseImageOpaqueMemoryBindInfo`.

To make this easier on the implementation, the `VK_SPARSE_MEMORY_BIND_METADATA_BIT` explicitly specifies when metadata is bound with `VkSparseImageOpaqueMemoryBindInfo`. When this flag is not present, the `resourceOffset` may be treated as a strict device virtual address offset.

When `VK_SPARSE_MEMORY_BIND_METADATA_BIT` is present, the `resourceOffset` must have been derived explicitly from the `imageMipTailOffset` in the sparse resource properties returned for the metadata aspect. By manipulating the value returned for `imageMipTailOffset`, the `resourceOffset` does not have to correlate directly to a device virtual address offset, and may instead be whatever values makes it easiest for the implementation to derive the correct device virtual address.

### 31.7. Sparse Resource API

The APIs related to sparse resources are grouped into the following categories:

- Physical Device Features

- Physical Device Sparse Properties

- Sparse Image Format Properties

- Sparse Resource Creation

- Sparse Resource Memory Requirements

- Binding Resource Memory

#### 31.7.1. Physical Device Features

Some sparse-resource related features are reported and enabled in `VkPhysicalDeviceFeatures`. These features must be supported and enabled on the `VkDevice` object before applications can use them. See Physical Device Features for information on how to get and set enabled device features, and for more detailed explanations of these features.

##### Sparse Physical Device Features

- `sparseBinding`: Support for creating VkBuffer and `VkImage` objects with the `VK_BUFFER_CREATE_SPARSE_BINDING_BIT` and `VK_IMAGE_CREATE_SPARSE_BINDING_BIT` flags, respectively.

- `sparseResidencyBuffer`: Support for creating VkBuffer objects with the `VK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT` flag.

- `sparseResidencyImage2D`: Support for creating 2D single-sampled `VkImage` objects with `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`.

- `sparseResidencyImage3D`: Support for creating 3D VkImage objects with `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`.

- `sparseResidency2Samples`: Support for creating 2D VkImage objects with 2 samples and `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`.

- `sparseResidency4Samples`: Support for creating 2D VkImage objects with 4 samples and `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`.

- `sparseResidency8Samples`: Support for creating 2D VkImage objects with 8 samples and `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`.

- `sparseResidency16Samples`: Support for creating 2D VkImage objects with 16 samples and `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`.

- `sparseResidencyAliased`: Support for creating VkBuffer and `VkImage` objects with the `VK_BUFFER_CREATE_SPARSE_ALIASED_BIT` and `VK_IMAGE_CREATE_SPARSE_ALIASED_BIT` flags, respectively.

#### 31.7.2. Physical Device Sparse Properties

Some features of the implementation are not possible to disable, and are reported to allow applications to alter their sparse resource usage accordingly. These read-only capabilities are reported in the VkPhysicalDeviceProperties::`sparseProperties` member, which is a structure of type `VkPhysicalDeviceSparseProperties`.

The `VkPhysicalDeviceSparseProperties` structure is defined as:

    typedef struct VkPhysicalDeviceSparseProperties {
        VkBool32    residencyStandard2DBlockShape;
        VkBool32    residencyStandard2DMultisampleBlockShape;
        VkBool32    residencyStandard3DBlockShape;
        VkBool32    residencyAlignedMipSize;
        VkBool32    residencyNonResidentStrict;
    } VkPhysicalDeviceSparseProperties;

- `residencyStandard2DBlockShape` is `VK_TRUE` if the physical device will access all single-sample 2D sparse resources using the standard sparse image block shapes (based on image format), as described in the Standard Sparse Image Block Shapes (Single Sample) table. If this property is not supported the value returned in the `imageGranularity` member of the `VkSparseImageFormatProperties` structure for single-sample 2D images is not required to match the standard sparse image block dimensions listed in the table.

- `residencyStandard2DMultisampleBlockShape` is `VK_TRUE` if the physical device will access all multisample 2D sparse resources using the standard sparse image block shapes (based on image format), as described in the Standard Sparse Image Block Shapes (MSAA) table. If this property is not supported, the value returned in the `imageGranularity` member of the `VkSparseImageFormatProperties` structure for multisample 2D images is not required to match the standard sparse image block dimensions listed in the table.

- `residencyStandard3DBlockShape` is `VK_TRUE` if the physical device will access all 3D sparse resources using the standard sparse image block shapes (based on image format), as described in the Standard Sparse Image Block Shapes (Single Sample) table. If this property is not supported, the value returned in the `imageGranularity` member of the `VkSparseImageFormatProperties` structure for 3D images is not required to match the standard sparse image block dimensions listed in the table.

- `residencyAlignedMipSize` is `VK_TRUE` if images with mip level dimensions that are not integer multiples of the corresponding dimensions of the sparse image block may be placed in the mip tail. If this property is not reported, only mip levels with dimensions smaller than the `imageGranularity` member of the `VkSparseImageFormatProperties` structure will be placed in the mip tail. If this property is reported the implementation is allowed to return `VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BIT` in the `flags` member of `VkSparseImageFormatProperties`, indicating that mip level dimensions that are not integer multiples of the corresponding dimensions of the sparse image block will be placed in the mip tail.

- `residencyNonResidentStrict` specifies whether the physical device can consistently access non-resident regions of a resource. If this property is `VK_TRUE`, access to non-resident regions of resources will be guaranteed to return values as if the resource were populated with 0; writes to non-resident regions will be discarded.

#### 31.7.3. Sparse Image Format Properties

Given that certain aspects of sparse image support, including the sparse image block dimensions, may be implementation-dependent, vkGetPhysicalDeviceSparseImageFormatProperties can be used to query for sparse image format properties prior to resource creation. This command is used to check whether a given set of sparse image parameters is supported and what the sparse image block shape will be.

##### Sparse Image Format Properties API

The `VkSparseImageFormatProperties` structure is defined as:

    typedef struct VkSparseImageFormatProperties {
        VkImageAspectFlags          aspectMask;
        VkExtent3D                  imageGranularity;
        VkSparseImageFormatFlags    flags;
    } VkSparseImageFormatProperties;

- `aspectMask` is a bitmask VkImageAspectFlagBits specifying which aspects of the image the properties apply to.

- `imageGranularity` is the width, height, and depth of the sparse image block in texels or compressed texel blocks.

- `flags` is a bitmask of VkSparseImageFormatFlagBits specifying additional information about the sparse resource.

Bits which may be set in VkSparseImageFormatProperties::`flags`, specifying additional information about the sparse resource, are:

    typedef enum VkSparseImageFormatFlagBits {
        VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT = 0x00000001,
        VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BIT = 0x00000002,
        VK_SPARSE_IMAGE_FORMAT_NONSTANDARD_BLOCK_SIZE_BIT = 0x00000004,
        VK_SPARSE_IMAGE_FORMAT_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkSparseImageFormatFlagBits;

- `VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT` specifies that the image uses a single mip tail region for all array layers.

- `VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BIT` specifies that the first mip level whose dimensions are not integer multiples of the corresponding dimensions of the sparse image block begins the mip tail region.

- `VK_SPARSE_IMAGE_FORMAT_NONSTANDARD_BLOCK_SIZE_BIT` specifies that the image uses non-standard sparse image block dimensions, and the `imageGranularity` values do not match the standard sparse image block dimensions for the given format.

    typedef VkFlags VkSparseImageFormatFlags;

`VkSparseImageFormatFlags` is a bitmask type for setting a mask of zero or more VkSparseImageFormatFlagBits.

`vkGetPhysicalDeviceSparseImageFormatProperties` returns an array of VkSparseImageFormatProperties. Each element will describe properties for one set of image aspects that are bound simultaneously in the image. This is usually one element for each aspect in the image, but for interleaved depth/stencil images there is only one element describing the combined aspects.

    void vkGetPhysicalDeviceSparseImageFormatProperties(
        VkPhysicalDevice                            physicalDevice,
        VkFormat                                    format,
        VkImageType                                 type,
        VkSampleCountFlagBits                       samples,
        VkImageUsageFlags                           usage,
        VkImageTiling                               tiling,
        uint32_t*                                   pPropertyCount,
        VkSparseImageFormatProperties*              pProperties);

- `physicalDevice` is the physical device from which to query the sparse image capabilities.

- `format` is the image format.

- `type` is the dimensionality of image.

- `samples` is the number of samples per texel as defined in VkSampleCountFlagBits.

- `usage` is a bitmask describing the intended usage of the image.

- `tiling` is the tiling arrangement of the texel blocks in memory.

- `pPropertyCount` is a pointer to an integer related to the number of sparse format properties available or queried, as described below.

- `pProperties` is either `NULL` or a pointer to an array of VkSparseImageFormatProperties structures.

If `pProperties` is `NULL`, then the number of sparse format properties available is returned in `pPropertyCount`. Otherwise, `pPropertyCount` must point to a variable set by the user to the number of elements in the `pProperties` array, and on return the variable is overwritten with the number of structures actually written to `pProperties`. If `pPropertyCount` is less than the number of sparse format properties available, at most `pPropertyCount` structures will be written.

If `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT` is not supported for the given arguments, `pPropertyCount` will be set to zero upon return, and no data will be written to `pProperties`.

Multiple aspects are returned for depth/stencil images that are implemented as separate planes by the implementation. The depth and stencil data planes each have unique `VkSparseImageFormatProperties` data.

Depth/stencil images with depth and stencil data interleaved into a single plane will return a single `VkSparseImageFormatProperties` structure with the `aspectMask` set to `VK_IMAGE_ASPECT_DEPTH_BIT` | `VK_IMAGE_ASPECT_STENCIL_BIT`.

Valid Usage

- `samples` must be a bit value that is set in `VkImageFormatProperties`::`sampleCounts` returned by `vkGetPhysicalDeviceImageFormatProperties` with `format`, `type`, `tiling`, and `usage` equal to those in this command and `flags` equal to the value that is set in `VkImageCreateInfo`::`flags` when the image is created

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `format` must be a valid VkFormat value

- `type` must be a valid VkImageType value

- `samples` must be a valid VkSampleCountFlagBits value

- `usage` must be a valid combination of VkImageUsageFlagBits values

- `usage` must not be `0`

- `tiling` must be a valid VkImageTiling value

- `pPropertyCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pPropertyCount` is not `0`, and `pProperties` is not `NULL`, `pProperties` must be a valid pointer to an array of `pPropertyCount` VkSparseImageFormatProperties structures

`vkGetPhysicalDeviceSparseImageFormatProperties2` returns an array of VkSparseImageFormatProperties2. Each element will describe properties for one set of image aspects that are bound simultaneously in the image. This is usually one element for each aspect in the image, but for interleaved depth/stencil images there is only one element describing the combined aspects.

    void vkGetPhysicalDeviceSparseImageFormatProperties2(
        VkPhysicalDevice                            physicalDevice,
        const VkPhysicalDeviceSparseImageFormatInfo2* pFormatInfo,
        uint32_t*                                   pPropertyCount,
        VkSparseImageFormatProperties2*             pProperties);

or the equivalent command

    void vkGetPhysicalDeviceSparseImageFormatProperties2KHR(
        VkPhysicalDevice                            physicalDevice,
        const VkPhysicalDeviceSparseImageFormatInfo2* pFormatInfo,
        uint32_t*                                   pPropertyCount,
        VkSparseImageFormatProperties2*             pProperties);

- `physicalDevice` is the physical device from which to query the sparse image capabilities.

- `pFormatInfo` is a pointer to a VkPhysicalDeviceSparseImageFormatInfo2 structure containing input parameters to the command.

- `pPropertyCount` is a pointer to an integer related to the number of sparse format properties available or queried, as described below.

- `pProperties` is either `NULL` or a pointer to an array of VkSparseImageFormatProperties2 structures.

`vkGetPhysicalDeviceSparseImageFormatProperties2` behaves identically to vkGetPhysicalDeviceSparseImageFormatProperties, with the ability to return extended information by adding extension structures to the `pNext` chain of its `pProperties` parameter.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pFormatInfo` must be a valid pointer to a valid VkPhysicalDeviceSparseImageFormatInfo2 structure

- `pPropertyCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pPropertyCount` is not `0`, and `pProperties` is not `NULL`, `pProperties` must be a valid pointer to an array of `pPropertyCount` VkSparseImageFormatProperties2 structures

The `VkPhysicalDeviceSparseImageFormatInfo2` structure is defined as:

    typedef struct VkPhysicalDeviceSparseImageFormatInfo2 {
        VkStructureType          sType;
        const void*              pNext;
        VkFormat                 format;
        VkImageType              type;
        VkSampleCountFlagBits    samples;
        VkImageUsageFlags        usage;
        VkImageTiling            tiling;
    } VkPhysicalDeviceSparseImageFormatInfo2;

or the equivalent

    typedef VkPhysicalDeviceSparseImageFormatInfo2 VkPhysicalDeviceSparseImageFormatInfo2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `format` is the image format.

- `type` is the dimensionality of image.

- `samples` is the number of samples per texel as defined in VkSampleCountFlagBits.

- `usage` is a bitmask describing the intended usage of the image.

- `tiling` is the tiling arrangement of the texel blocks in memory.

Valid Usage

- `samples` must be a bit value that is set in `VkImageFormatProperties`::`sampleCounts` returned by `vkGetPhysicalDeviceImageFormatProperties` with `format`, `type`, `tiling`, and `usage` equal to those in this command and `flags` equal to the value that is set in `VkImageCreateInfo`::`flags` when the image is created

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SPARSE_IMAGE_FORMAT_INFO_2`

- `pNext` must be `NULL`

- `format` must be a valid VkFormat value

- `type` must be a valid VkImageType value

- `samples` must be a valid VkSampleCountFlagBits value

- `usage` must be a valid combination of VkImageUsageFlagBits values

- `usage` must not be `0`

- `tiling` must be a valid VkImageTiling value

The `VkSparseImageFormatProperties2` structure is defined as:

    typedef struct VkSparseImageFormatProperties2 {
        VkStructureType                  sType;
        void*                            pNext;
        VkSparseImageFormatProperties    properties;
    } VkSparseImageFormatProperties2;

or the equivalent

    typedef VkSparseImageFormatProperties2 VkSparseImageFormatProperties2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `properties` is a VkSparseImageFormatProperties structure which is populated with the same values as in vkGetPhysicalDeviceSparseImageFormatProperties.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SPARSE_IMAGE_FORMAT_PROPERTIES_2`

- `pNext` must be `NULL`

#### 31.7.4. Sparse Resource Creation

Sparse resources require that one or more sparse feature flags be specified (as part of the `VkPhysicalDeviceFeatures` structure described previously in the Physical Device Features section) at CreateDevice time. When the appropriate device features are enabled, the `VK_BUFFER_CREATE_SPARSE_*` and `VK_IMAGE_CREATE_SPARSE_*` flags can be used. See vkCreateBuffer and vkCreateImage for details of the resource creation APIs.

| Note Specifying `VK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT` or `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT` requires specifying `VK_BUFFER_CREATE_SPARSE_BINDING_BIT` or `VK_IMAGE_CREATE_SPARSE_BINDING_BIT`, respectively, as well. This means that resources must be created with the appropriate `*_SPARSE_BINDING_BIT` to be used with the sparse binding command (`vkQueueBindSparse`).

#### 31.7.5. Sparse Resource Memory Requirements

Sparse resources have specific memory requirements related to binding sparse memory. These memory requirements are reported differently for `VkBuffer` objects and `VkImage` objects.

##### Buffer and Fully-Resident Images

Buffers (both fully and partially resident) and fully-resident images can be bound to memory using only the data from `VkMemoryRequirements`. For all sparse resources the `VkMemoryRequirements`::`alignment` member specifies both the bindable sparse block size in bytes and required alignment of `VkDeviceMemory`.

##### Partially Resident Images

Partially resident images have a different method for binding memory. As with buffers and fully resident images, the `VkMemoryRequirements`::`alignment` field specifies the bindable sparse block size in bytes for the image.

Requesting sparse memory requirements for `VkImage` objects using `vkGetImageSparseMemoryRequirements` will return an array of one or more `VkSparseImageMemoryRequirements` structures. Each structure describes the sparse memory requirements for a group of aspects of the image.

The sparse image must have been created using the `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT` flag to retrieve valid sparse image memory requirements.

##### Sparse Image Memory Requirements

The `VkSparseImageMemoryRequirements` structure is defined as:

    typedef struct VkSparseImageMemoryRequirements {
        VkSparseImageFormatProperties    formatProperties;
        uint32_t                         imageMipTailFirstLod;
        VkDeviceSize                     imageMipTailSize;
        VkDeviceSize                     imageMipTailOffset;
        VkDeviceSize                     imageMipTailStride;
    } VkSparseImageMemoryRequirements;

- `formatProperties.aspectMask` is the set of aspects of the image that this sparse memory requirement applies to. This will usually have a single aspect specified. However, depth/stencil images may have depth and stencil data interleaved in the same sparse block, in which case both `VK_IMAGE_ASPECT_DEPTH_BIT` and `VK_IMAGE_ASPECT_STENCIL_BIT` would be present.

- `formatProperties.imageGranularity` describes the dimensions of a single bindable sparse image block in texel units. For aspect `VK_IMAGE_ASPECT_METADATA_BIT`, all dimensions will be zero. All metadata is located in the mip tail region.

- `formatProperties.flags` is a bitmask of VkSparseImageFormatFlagBits:

  - If `VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT` is set the image uses a single mip tail region for all array layers.

  - If `VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BIT` is set the dimensions of mip levels must be integer multiples of the corresponding dimensions of the sparse image block for levels not located in the mip tail.

  - If `VK_SPARSE_IMAGE_FORMAT_NONSTANDARD_BLOCK_SIZE_BIT` is set the image uses non-standard sparse image block dimensions. The `formatProperties.imageGranularity` values do not match the standard sparse image block dimension corresponding to the image’s format.

- `imageMipTailFirstLod` is the first mip level at which image subresources are included in the mip tail region.

- `imageMipTailSize` is the memory size (in bytes) of the mip tail region. If `formatProperties.flags` contains `VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT`, this is the size of the whole mip tail, otherwise this is the size of the mip tail of a single array layer. This value is guaranteed to be a multiple of the sparse block size in bytes.

- `imageMipTailOffset` is the opaque memory offset used with VkSparseImageOpaqueMemoryBindInfo to bind the mip tail region(s).

- `imageMipTailStride` is the offset stride between each array-layer’s mip tail, if `formatProperties.flags` does not contain `VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT` (otherwise the value is undefined).

To query sparse memory requirements for an image, call:

    void vkGetImageSparseMemoryRequirements(
        VkDevice                                    device,
        VkImage                                     image,
        uint32_t*                                   pSparseMemoryRequirementCount,
        VkSparseImageMemoryRequirements*            pSparseMemoryRequirements);

- `device` is the logical device that owns the image.

- `image` is the VkImage object to get the memory requirements for.

- `pSparseMemoryRequirementCount` is a pointer to an integer related to the number of sparse memory requirements available or queried, as described below.

- `pSparseMemoryRequirements` is either `NULL` or a pointer to an array of `VkSparseImageMemoryRequirements` structures.

If `pSparseMemoryRequirements` is `NULL`, then the number of sparse memory requirements available is returned in `pSparseMemoryRequirementCount`. Otherwise, `pSparseMemoryRequirementCount` must point to a variable set by the user to the number of elements in the `pSparseMemoryRequirements` array, and on return the variable is overwritten with the number of structures actually written to `pSparseMemoryRequirements`. If `pSparseMemoryRequirementCount` is less than the number of sparse memory requirements available, at most `pSparseMemoryRequirementCount` structures will be written.

If the image was not created with `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT` then `pSparseMemoryRequirementCount` will be set to zero and `pSparseMemoryRequirements` will not be written to.

| Note It is legal for an implementation to report a larger value in `VkMemoryRequirements`::`size` than would be obtained by adding together memory sizes for all `VkSparseImageMemoryRequirements` returned by `vkGetImageSparseMemoryRequirements`. This may occur when the implementation requires unused padding in the address range describing the resource.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `image` must be a valid VkImage handle

- `pSparseMemoryRequirementCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pSparseMemoryRequirementCount` is not `0`, and `pSparseMemoryRequirements` is not `NULL`, `pSparseMemoryRequirements` must be a valid pointer to an array of `pSparseMemoryRequirementCount` VkSparseImageMemoryRequirements structures

- `image` must have been created, allocated, or retrieved from `device`

To query sparse memory requirements for an image, call:

    void vkGetImageSparseMemoryRequirements2(
        VkDevice                                    device,
        const VkImageSparseMemoryRequirementsInfo2* pInfo,
        uint32_t*                                   pSparseMemoryRequirementCount,
        VkSparseImageMemoryRequirements2*           pSparseMemoryRequirements);

or the equivalent command

    void vkGetImageSparseMemoryRequirements2KHR(
        VkDevice                                    device,
        const VkImageSparseMemoryRequirementsInfo2* pInfo,
        uint32_t*                                   pSparseMemoryRequirementCount,
        VkSparseImageMemoryRequirements2*           pSparseMemoryRequirements);

- `device` is the logical device that owns the image.

- `pInfo` is a pointer to a `VkImageSparseMemoryRequirementsInfo2` structure containing parameters required for the memory requirements query.

- `pSparseMemoryRequirementCount` is a pointer to an integer related to the number of sparse memory requirements available or queried, as described below.

- `pSparseMemoryRequirements` is either `NULL` or a pointer to an array of `VkSparseImageMemoryRequirements2` structures.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pInfo` must be a valid pointer to a valid VkImageSparseMemoryRequirementsInfo2 structure

- `pSparseMemoryRequirementCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pSparseMemoryRequirementCount` is not `0`, and `pSparseMemoryRequirements` is not `NULL`, `pSparseMemoryRequirements` must be a valid pointer to an array of `pSparseMemoryRequirementCount` VkSparseImageMemoryRequirements2 structures

The `VkImageSparseMemoryRequirementsInfo2` structure is defined as:

    typedef struct VkImageSparseMemoryRequirementsInfo2 {
        VkStructureType    sType;
        const void*        pNext;
        VkImage            image;
    } VkImageSparseMemoryRequirementsInfo2;

or the equivalent

    typedef VkImageSparseMemoryRequirementsInfo2 VkImageSparseMemoryRequirementsInfo2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `image` is the image to query.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMAGE_SPARSE_MEMORY_REQUIREMENTS_INFO_2`

- `pNext` must be `NULL`

- `image` must be a valid VkImage handle

The `VkSparseImageMemoryRequirements2` structure is defined as:

    typedef struct VkSparseImageMemoryRequirements2 {
        VkStructureType                    sType;
        void*                              pNext;
        VkSparseImageMemoryRequirements    memoryRequirements;
    } VkSparseImageMemoryRequirements2;

or the equivalent

    typedef VkSparseImageMemoryRequirements2 VkSparseImageMemoryRequirements2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `memoryRequirements` is a VkSparseImageMemoryRequirements structure describing the memory requirements of the sparse image.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SPARSE_IMAGE_MEMORY_REQUIREMENTS_2`

- `pNext` must be `NULL`

#### 31.7.6. Binding Resource Memory

Non-sparse resources are backed by a single physical allocation prior to device use (via `vkBindImageMemory` or `vkBindBufferMemory`), and their backing must not be changed. On the other hand, sparse resources can be bound to memory non-contiguously and these bindings can be altered during the lifetime of the resource.

| Note It is important to note that freeing a `VkDeviceMemory` object with `vkFreeMemory` will not cause resources (or resource regions) bound to the memory object to become unbound. Applications must not access resources bound to memory that has been freed.

Sparse memory bindings execute on a queue that includes the `VK_QUEUE_SPARSE_BINDING_BIT` bit. Applications must use synchronization primitives to guarantee that other queues do not access ranges of memory concurrently with a binding change. Applications can access other ranges of the same resource while a bind operation is executing.

| Note Implementations must provide a guarantee that simultaneously binding sparse blocks while another queue accesses those same sparse blocks via a sparse resource must not access memory owned by another process or otherwise corrupt the system.

While some implementations may include `VK_QUEUE_SPARSE_BINDING_BIT` support in queue families that also include graphics and compute support, other implementations may only expose a `VK_QUEUE_SPARSE_BINDING_BIT`-only queue family. In either case, applications must use synchronization primitives to explicitly request any ordering dependencies between sparse memory binding operations and other graphics/compute/transfer operations, as sparse binding operations are not automatically ordered against command buffer execution, even within a single queue.

When binding memory explicitly for the `VK_IMAGE_ASPECT_METADATA_BIT` the application must use the `VK_SPARSE_MEMORY_BIND_METADATA_BIT` in the `VkSparseMemoryBind`::`flags` field when binding memory. Binding memory for metadata is done the same way as binding memory for the mip tail, with the addition of the `VK_SPARSE_MEMORY_BIND_METADATA_BIT` flag.

Binding the mip tail for any aspect must only be performed using VkSparseImageOpaqueMemoryBindInfo. If `formatProperties.flags` contains `VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT`, then it can be bound with a single VkSparseMemoryBind structure, with `resourceOffset` = `imageMipTailOffset` and `size` = `imageMipTailSize`.

If `formatProperties.flags` does not contain `VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT` then the offset for the mip tail in each array layer is given as:

    arrayMipTailOffset = imageMipTailOffset + arrayLayer * imageMipTailStride;

and the mip tail can be bound with `layerCount` VkSparseMemoryBind structures, each using `size` = `imageMipTailSize` and `resourceOffset` = `arrayMipTailOffset` as defined above.

Sparse memory binding is handled by the following APIs and related data structures.

##### Sparse Memory Binding Functions

The `VkSparseMemoryBind` structure is defined as:

    typedef struct VkSparseMemoryBind {
        VkDeviceSize               resourceOffset;
        VkDeviceSize               size;
        VkDeviceMemory             memory;
        VkDeviceSize               memoryOffset;
        VkSparseMemoryBindFlags    flags;
    } VkSparseMemoryBind;

- `resourceOffset` is the offset into the resource.

- `size` is the size of the memory region to be bound.

- `memory` is the VkDeviceMemory object that the range of the resource is bound to. If `memory` is VK_NULL_HANDLE, the range is unbound.

- `memoryOffset` is the offset into the VkDeviceMemory object to bind the resource range to. If `memory` is VK_NULL_HANDLE, this value is ignored.

- `flags` is a bitmask of VkSparseMemoryBindFlagBits specifying usage of the binding operation.

The binding range [`resourceOffset`, `resourceOffset` + `size`) has different constraints based on `flags`. If `flags` contains `VK_SPARSE_MEMORY_BIND_METADATA_BIT`, the binding range must be within the mip tail region of the metadata aspect. This metadata region is defined by:

  metadataRegion = [base, base + `imageMipTailSize`)

  base = `imageMipTailOffset` + `imageMipTailStride` × n

and `imageMipTailOffset`, `imageMipTailSize`, and `imageMipTailStride` values are from the VkSparseImageMemoryRequirements corresponding to the metadata aspect of the image, and n is a valid array layer index for the image,

`imageMipTailStride` is considered to be zero for aspects where `VkSparseImageMemoryRequirements`::`formatProperties.flags` contains `VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT`.

If `flags` does not contain `VK_SPARSE_MEMORY_BIND_METADATA_BIT`, the binding range must be within the range [0,VkMemoryRequirements::`size`).

Valid Usage

- If `memory` is not VK_NULL_HANDLE, `memory` and `memoryOffset` must match the memory requirements of the resource, as described in section Resource Memory Association

- If `memory` is not VK_NULL_HANDLE, `memory` must not have been created with a memory type that reports `VK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BIT` bit set

- `size` must be greater than `0`

- `resourceOffset` must be less than the size of the resource

- `size` must be less than or equal to the size of the resource minus `resourceOffset`

- `memoryOffset` must be less than the size of `memory`

- `size` must be less than or equal to the size of `memory` minus `memoryOffset`

- If `memory` was created with VkExportMemoryAllocateInfo::`handleTypes` not equal to `0`, at least one handle type it contained must also have been set in VkExternalMemoryBufferCreateInfo::`handleTypes` or VkExternalMemoryImageCreateInfo::`handleTypes` when the resource was created.

- If `memory` was created by a memory import operation, the external handle type of the imported memory must also have been set in VkExternalMemoryBufferCreateInfo::`handleTypes` or VkExternalMemoryImageCreateInfo::`handleTypes` when the resource was created.

Valid Usage (Implicit)

- If `memory` is not VK_NULL_HANDLE, `memory` must be a valid VkDeviceMemory handle

- `flags` must be a valid combination of VkSparseMemoryBindFlagBits values

Bits which can be set in VkSparseMemoryBind::`flags`, specifying usage of a sparse memory binding operation, are:

    typedef enum VkSparseMemoryBindFlagBits {
        VK_SPARSE_MEMORY_BIND_METADATA_BIT = 0x00000001,
        VK_SPARSE_MEMORY_BIND_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkSparseMemoryBindFlagBits;

- `VK_SPARSE_MEMORY_BIND_METADATA_BIT` specifies that the memory being bound is only for the metadata aspect.

    typedef VkFlags VkSparseMemoryBindFlags;

`VkSparseMemoryBindFlags` is a bitmask type for setting a mask of zero or more VkSparseMemoryBindFlagBits.

Memory is bound to `VkBuffer` objects created with the `VK_BUFFER_CREATE_SPARSE_BINDING_BIT` flag using the following structure:

    typedef struct VkSparseBufferMemoryBindInfo {
        VkBuffer                     buffer;
        uint32_t                     bindCount;
        const VkSparseMemoryBind*    pBinds;
    } VkSparseBufferMemoryBindInfo;

- `buffer` is the VkBuffer object to be bound.

- `bindCount` is the number of VkSparseMemoryBind structures in the `pBinds` array.

- `pBinds` is a pointer to array of VkSparseMemoryBind structures.

Valid Usage (Implicit)

- `buffer` must be a valid VkBuffer handle

- `pBinds` must be a valid pointer to an array of `bindCount` valid VkSparseMemoryBind structures

- `bindCount` must be greater than `0`

Memory is bound to opaque regions of `VkImage` objects created with the `VK_IMAGE_CREATE_SPARSE_BINDING_BIT` flag using the following structure:

    typedef struct VkSparseImageOpaqueMemoryBindInfo {
        VkImage                      image;
        uint32_t                     bindCount;
        const VkSparseMemoryBind*    pBinds;
    } VkSparseImageOpaqueMemoryBindInfo;

- `image` is the VkImage object to be bound.

- `bindCount` is the number of VkSparseMemoryBind structures in the `pBinds` array.

- `pBinds` is a pointer to an array of VkSparseMemoryBind structures.

Valid Usage

- If the `flags` member of any element of `pBinds` contains `VK_SPARSE_MEMORY_BIND_METADATA_BIT`, the binding range defined must be within the mip tail region of the metadata aspect of `image`

Valid Usage (Implicit)

- `image` must be a valid VkImage handle

- `pBinds` must be a valid pointer to an array of `bindCount` valid VkSparseMemoryBind structures

- `bindCount` must be greater than `0`

| Note This operation is normally used to bind memory to fully-resident sparse images or for mip tail regions of partially resident images. However, it can also be used to bind memory for the entire binding range of partially resident images. In case `flags` does not contain `VK_SPARSE_MEMORY_BIND_METADATA_BIT`, the `resourceOffset` is in the range [0, VkMemoryRequirements::`size`), This range includes data from all aspects of the image, including metadata. For most implementations this will probably mean that the `resourceOffset` is a simple device address offset within the resource. It is possible for an application to bind a range of memory that includes both resource data and metadata. However, the application would not know what part of the image the memory is used for, or if any range is being used for metadata. When `flags` contains `VK_SPARSE_MEMORY_BIND_METADATA_BIT`, the binding range specified must be within the mip tail region of the metadata aspect. In this case the `resourceOffset` is not required to be a simple device address offset within the resource. However, it is defined to be within [`imageMipTailOffset`, `imageMipTailOffset` + `imageMipTailSize`) for the metadata aspect. See VkSparseMemoryBind for the full constraints on binding region with this flag present.

| editing-note (Jon) The preceding NOTE refers to `flags`, which is presumably a reference to VkSparseMemoryBind above, even though that is not contextually clear.

Memory can be bound to sparse image blocks of `VkImage` objects created with the `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT` flag using the following structure:

    typedef struct VkSparseImageMemoryBindInfo {
        VkImage                           image;
        uint32_t                          bindCount;
        const VkSparseImageMemoryBind*    pBinds;
    } VkSparseImageMemoryBindInfo;

- `image` is the VkImage object to be bound

- `bindCount` is the number of VkSparseImageMemoryBind structures in `pBinds` array

- `pBinds` is a pointer to an array of VkSparseImageMemoryBind structures

Valid Usage

- The `subresource.mipLevel` member of each element of `pBinds` must be less than the `mipLevels` specified in VkImageCreateInfo when `image` was created

- The `subresource.arrayLayer` member of each element of `pBinds` must be less than the `arrayLayers` specified in VkImageCreateInfo when `image` was created

- `image` must have been created with `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT` set

Valid Usage (Implicit)

- `image` must be a valid VkImage handle

- `pBinds` must be a valid pointer to an array of `bindCount` valid VkSparseImageMemoryBind structures

- `bindCount` must be greater than `0`

The `VkSparseImageMemoryBind` structure is defined as:

    typedef struct VkSparseImageMemoryBind {
        VkImageSubresource         subresource;
        VkOffset3D                 offset;
        VkExtent3D                 extent;
        VkDeviceMemory             memory;
        VkDeviceSize               memoryOffset;
        VkSparseMemoryBindFlags    flags;
    } VkSparseImageMemoryBind;

- `subresource` is the image aspect and region of interest in the image.

- `offset` are the coordinates of the first texel within the image subresource to bind.

- `extent` is the size in texels of the region within the image subresource to bind. The extent must be a multiple of the sparse image block dimensions, except when binding sparse image blocks along the edge of an image subresource it can instead be such that any coordinate of `offset` + `extent` equals the corresponding dimensions of the image subresource.

- `memory` is the VkDeviceMemory object that the sparse image blocks of the image are bound to. If `memory` is VK_NULL_HANDLE, the sparse image blocks are unbound.

- `memoryOffset` is an offset into VkDeviceMemory object. If `memory` is VK_NULL_HANDLE, this value is ignored.

- `flags` are sparse memory binding flags.

Valid Usage

- If the sparse aliased residency feature is not enabled, and if any other resources are bound to ranges of `memory`, the range of `memory` being bound must not overlap with those bound ranges

- `memory` and `memoryOffset` must match the memory requirements of the calling command’s `image`, as described in section Resource Memory Association

- `subresource` must be a valid image subresource for `image` (see Image Views)

- `offset.x` must be a multiple of the sparse image block width (`VkSparseImageFormatProperties`::`imageGranularity.width`) of the image

- `extent.width` must either be a multiple of the sparse image block width of the image, or else (`extent.width` + `offset.x`) must equal the width of the image subresource

- `offset.y` must be a multiple of the sparse image block height (`VkSparseImageFormatProperties`::`imageGranularity.height`) of the image

- `extent.height` must either be a multiple of the sparse image block height of the image, or else (`extent.height` + `offset.y`) must equal the height of the image subresource

- `offset.z` must be a multiple of the sparse image block depth (`VkSparseImageFormatProperties`::`imageGranularity.depth`) of the image

- `extent.depth` must either be a multiple of the sparse image block depth of the image, or else (`extent.depth` + `offset.z`) must equal the depth of the image subresource

- If `memory` was created with VkExportMemoryAllocateInfo::`handleTypes` not equal to `0`, at least one handle type it contained must also have been set in VkExternalMemoryImageCreateInfo::`handleTypes` when the image was created.

- If `memory` was created by a memory import operation, the external handle type of the imported memory must also have been set in VkExternalMemoryImageCreateInfo::`handleTypes` when `image` was created.

Valid Usage (Implicit)

- `subresource` must be a valid VkImageSubresource structure

- If `memory` is not VK_NULL_HANDLE, `memory` must be a valid VkDeviceMemory handle

- `flags` must be a valid combination of VkSparseMemoryBindFlagBits values

To submit sparse binding operations to a queue, call:

    VkResult vkQueueBindSparse(
        VkQueue                                     queue,
        uint32_t                                    bindInfoCount,
        const VkBindSparseInfo*                     pBindInfo,
        VkFence                                     fence);

- `queue` is the queue that the sparse binding operations will be submitted to.

- `bindInfoCount` is the number of elements in the `pBindInfo` array.

- `pBindInfo` is a pointer to an array of VkBindSparseInfo structures, each specifying a sparse binding submission batch.

- `fence` is an optional handle to a fence to be signaled. If `fence` is not VK_NULL_HANDLE, it defines a fence signal operation.

`vkQueueBindSparse` is a queue submission command, with each batch defined by an element of `pBindInfo` as a VkBindSparseInfo structure. Batches begin execution in the order they appear in `pBindInfo`, but may complete out of order.

Within a batch, a given range of a resource must not be bound more than once. Across batches, if a range is to be bound to one allocation and offset and then to another allocation and offset, then the application must guarantee (usually using semaphores) that the binding operations are executed in the correct order, as well as to order binding operations against the execution of command buffer submissions.

As no operation to vkQueueBindSparse causes any pipeline stage to access memory, synchronization primitives used in this command effectively only define execution dependencies.

Additional information about fence and semaphore operation is described in the synchronization chapter.

Valid Usage

- If `fence` is not VK_NULL_HANDLE, `fence` must be unsignaled

- If `fence` is not VK_NULL_HANDLE, `fence` must not be associated with any other queue command that has not yet completed execution on that queue

- Each element of the `pSignalSemaphores` member of each element of `pBindInfo` must be unsignaled when the semaphore signal operation it defines is executed on the device

- When a semaphore wait operation referring to a binary semaphore defined by any element of the `pWaitSemaphores` member of any element of `pBindInfo` executes on `queue`, there must be no other queues waiting on the same semaphore.

- All elements of the `pWaitSemaphores` member of all elements of `pBindInfo` member referring to a binary semaphore must be semaphores that are signaled, or have semaphore signal operations previously submitted for execution.

- All elements of the `pWaitSemaphores` member of all elements of `pBindInfo` created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_BINARY` must reference a semaphore signal operation that has been submitted for execution and any semaphore signal operations on which it depends (if any) must have also been submitted for execution.

Valid Usage (Implicit)

- `queue` must be a valid VkQueue handle

- If `bindInfoCount` is not `0`, `pBindInfo` must be a valid pointer to an array of `bindInfoCount` valid VkBindSparseInfo structures

- If `fence` is not VK_NULL_HANDLE, `fence` must be a valid VkFence handle

- The `queue` must support sparse binding operations

- Both of `fence`, and `queue` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `queue` must be externally synchronized

- Host access to `pBindInfo`[].pBufferBinds[].buffer must be externally synchronized

- Host access to `pBindInfo`[].pImageOpaqueBinds[].image must be externally synchronized

- Host access to `pBindInfo`[].pImageBinds[].image must be externally synchronized

- Host access to `fence` must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
- | - | SPARSE_BINDING | -

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_DEVICE_LOST`

The `VkBindSparseInfo` structure is defined as:

    typedef struct VkBindSparseInfo {
        VkStructureType                             sType;
        const void*                                 pNext;
        uint32_t                                    waitSemaphoreCount;
        const VkSemaphore*                          pWaitSemaphores;
        uint32_t                                    bufferBindCount;
        const VkSparseBufferMemoryBindInfo*         pBufferBinds;
        uint32_t                                    imageOpaqueBindCount;
        const VkSparseImageOpaqueMemoryBindInfo*    pImageOpaqueBinds;
        uint32_t                                    imageBindCount;
        const VkSparseImageMemoryBindInfo*          pImageBinds;
        uint32_t                                    signalSemaphoreCount;
        const VkSemaphore*                          pSignalSemaphores;
    } VkBindSparseInfo;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `waitSemaphoreCount` is the number of semaphores upon which to wait before executing the sparse binding operations for the batch.

- `pWaitSemaphores` is a pointer to an array of semaphores upon which to wait on before the sparse binding operations for this batch begin execution. If semaphores to wait on are provided, they define a semaphore wait operation.

- `bufferBindCount` is the number of sparse buffer bindings to perform in the batch.

- `pBufferBinds` is a pointer to an array of VkSparseBufferMemoryBindInfo structures.

- `imageOpaqueBindCount` is the number of opaque sparse image bindings to perform.

- `pImageOpaqueBinds` is a pointer to an array of VkSparseImageOpaqueMemoryBindInfo structures, indicating opaque sparse image bindings to perform.

- `imageBindCount` is the number of sparse image bindings to perform.

- `pImageBinds` is a pointer to an array of VkSparseImageMemoryBindInfo structures, indicating sparse image bindings to perform.

- `signalSemaphoreCount` is the number of semaphores to be signaled once the sparse binding operations specified by the structure have completed execution.

- `pSignalSemaphores` is a pointer to an array of semaphores which will be signaled when the sparse binding operations for this batch have completed execution. If semaphores to be signaled are provided, they define a semaphore signal operation.

Valid Usage

- If any element of `pWaitSemaphores` or `pSignalSemaphores` was created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE` then the `pNext` chain must include a VkTimelineSemaphoreSubmitInfo structure

- If the `pNext` chain of this structure includes a VkTimelineSemaphoreSubmitInfo structure and any element of `pWaitSemaphores` was created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE` then its `waitSemaphoreValueCount` member must equal `waitSemaphoreCount`

- If the `pNext` chain of this structure includes a VkTimelineSemaphoreSubmitInfo structure and any element of `pSignalSemaphores` was created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE` then its `signalSemaphoreValueCount` member must equal `signalSemaphoreCount`

- For each element of `pSignalSemaphores` created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE` the corresponding element of VkTimelineSemaphoreSubmitInfo::pSignalSemaphoreValues must have a value greater than the current value of the semaphore when the semaphore signal operation is executed

- For each element of `pWaitSemaphores` created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE` the corresponding element of VkTimelineSemaphoreSubmitInfo::pWaitSemaphoreValues must have a value which does not differ from the current value of the semaphore or from the value of any outstanding semaphore wait or signal operation on that semaphore by more than `maxTimelineSemaphoreValueDifference`.

- For each element of `pSignalSemaphores` created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE` the corresponding element of VkTimelineSemaphoreSubmitInfo::pSignalSemaphoreValues must have a value which does not differ from the current value of the semaphore or from the value of any outstanding semaphore wait or signal operation on that semaphore by more than `maxTimelineSemaphoreValueDifference`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_BIND_SPARSE_INFO`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkDeviceGroupBindSparseInfo or VkTimelineSemaphoreSubmitInfo

- The `sType` value of each struct in the `pNext` chain must be unique

- If `waitSemaphoreCount` is not `0`, `pWaitSemaphores` must be a valid pointer to an array of `waitSemaphoreCount` valid VkSemaphore handles

- If `bufferBindCount` is not `0`, `pBufferBinds` must be a valid pointer to an array of `bufferBindCount` valid VkSparseBufferMemoryBindInfo structures

- If `imageOpaqueBindCount` is not `0`, `pImageOpaqueBinds` must be a valid pointer to an array of `imageOpaqueBindCount` valid VkSparseImageOpaqueMemoryBindInfo structures

- If `imageBindCount` is not `0`, `pImageBinds` must be a valid pointer to an array of `imageBindCount` valid VkSparseImageMemoryBindInfo structures

- If `signalSemaphoreCount` is not `0`, `pSignalSemaphores` must be a valid pointer to an array of `signalSemaphoreCount` valid VkSemaphore handles

- Both of the elements of `pSignalSemaphores`, and the elements of `pWaitSemaphores` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

To specify the values to use when waiting for and signaling semaphores created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE`, add a VkTimelineSemaphoreSubmitInfo structure to the `pNext` chain of the VkBindSparseInfo structure.

If the `pNext` chain of VkBindSparseInfo includes a `VkDeviceGroupBindSparseInfo` structure, then that structure includes device indices specifying which instance of the resources and memory are bound.

The `VkDeviceGroupBindSparseInfo` structure is defined as:

    typedef struct VkDeviceGroupBindSparseInfo {
        VkStructureType    sType;
        const void*        pNext;
        uint32_t           resourceDeviceIndex;
        uint32_t           memoryDeviceIndex;
    } VkDeviceGroupBindSparseInfo;

or the equivalent

    typedef VkDeviceGroupBindSparseInfo VkDeviceGroupBindSparseInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `resourceDeviceIndex` is a device index indicating which instance of the resource is bound.

- `memoryDeviceIndex` is a device index indicating which instance of the memory the resource instance is bound to.

These device indices apply to all buffer and image memory binds included in the batch pointing to this structure. The semaphore waits and signals for the batch are executed only by the physical device specified by the `resourceDeviceIndex`.

If this structure is not present, `resourceDeviceIndex` and `memoryDeviceIndex` are assumed to be zero.

Valid Usage

- `resourceDeviceIndex` and `memoryDeviceIndex` must both be valid device indices.

- Each memory allocation bound in this batch must have allocated an instance for `memoryDeviceIndex`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEVICE_GROUP_BIND_SPARSE_INFO`

### 31.8. Examples

The following examples illustrate basic creation of sparse images and binding them to physical memory.

#### 31.8.1. Basic Sparse Resources

This basic example creates a normal `VkImage` object but uses fine-grained memory allocation to back the resource with multiple memory ranges.

    VkDevice                device;
    VkQueue                 queue;
    VkImage                 sparseImage;
    VkAllocationCallbacks*  pAllocator = NULL;
    VkMemoryRequirements    memoryRequirements = {};
    VkDeviceSize            offset = 0;
    VkSparseMemoryBind      binds[MAX_CHUNKS] = {}; // MAX_CHUNKS is NOT part of Vulkan
    uint32_t                bindCount = 0;

    // ...

    // Allocate image object
    const VkImageCreateInfo sparseImageInfo =
    {
        VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO,        // sType
        NULL,                                       // pNext
        VK_IMAGE_CREATE_SPARSE_BINDING_BIT | ...,   // flags
        ...
    };
    vkCreateImage(device, &sparseImageInfo, pAllocator, &sparseImage);

    // Get memory requirements
    vkGetImageMemoryRequirements(
        device,
        sparseImage,
        &memoryRequirements);

    // Bind memory in fine-grained fashion, find available memory ranges
    // from potentially multiple VkDeviceMemory pools.
    // (Illustration purposes only, can be optimized for perf)
    while (memoryRequirements.size && bindCount < MAX_CHUNKS)
    {
        VkSparseMemoryBind* pBind = &binds[bindCount];
        pBind->resourceOffset = offset;

        AllocateOrGetMemoryRange(
            device,
            &memoryRequirements,
            &pBind->memory,
            &pBind->memoryOffset,
            &pBind->size);

        // memory ranges must be sized as multiples of the alignment
        assert(IsMultiple(pBind->size, memoryRequirements.alignment));
        assert(IsMultiple(pBind->memoryOffset, memoryRequirements.alignment));

        memoryRequirements.size -= pBind->size;
        offset                  += pBind->size;
        bindCount++;
    }

    // Ensure all image has backing
    if (memoryRequirements.size)
    {
        // Error condition - too many chunks
    }

    const VkSparseImageOpaqueMemoryBindInfo opaqueBindInfo =
    {
        sparseImage,                                // image
        bindCount,                                  // bindCount
        binds                                       // pBinds
    };

    const VkBindSparseInfo bindSparseInfo =
    {
        VK_STRUCTURE_TYPE_BIND_SPARSE_INFO,         // sType
        NULL,                                       // pNext
        ...
        1,                                          // imageOpaqueBindCount
        &opaqueBindInfo,                            // pImageOpaqueBinds
        ...
    };

    // vkQueueBindSparse is externally synchronized per queue object.
    AcquireQueueOwnership(queue);

    // Actually bind memory
    vkQueueBindSparse(queue, 1, &bindSparseInfo, VK_NULL_HANDLE);

    ReleaseQueueOwnership(queue);

#### 31.8.2. Advanced Sparse Resources

This more advanced example creates an arrayed color attachment / texture image and binds only LOD zero and the required metadata to physical memory.

    VkDevice                            device;
    VkQueue                             queue;
    VkImage                             sparseImage;
    VkAllocationCallbacks*              pAllocator = NULL;
    VkMemoryRequirements                memoryRequirements = {};
    uint32_t                            sparseRequirementsCount = 0;
    VkSparseImageMemoryRequirements*    pSparseReqs = NULL;
    VkSparseMemoryBind                  binds[MY_IMAGE_ARRAY_SIZE] = {};
    VkSparseImageMemoryBind             imageBinds[MY_IMAGE_ARRAY_SIZE] = {};
    uint32_t                            bindCount = 0;

    // Allocate image object (both renderable and sampleable)
    const VkImageCreateInfo sparseImageInfo =
    {
        VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO,        // sType
        NULL,                                       // pNext
        VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT | ..., // flags
        ...
        VK_FORMAT_R8G8B8A8_UNORM,                   // format
        ...
        MY_IMAGE_ARRAY_SIZE,                        // arrayLayers
        ...
        VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT |
        VK_IMAGE_USAGE_SAMPLED_BIT,                 // usage
        ...
    };
    vkCreateImage(device, &sparseImageInfo, pAllocator, &sparseImage);

    // Get memory requirements
    vkGetImageMemoryRequirements(
        device,
        sparseImage,
        &memoryRequirements);

    // Get sparse image aspect properties
    vkGetImageSparseMemoryRequirements(
        device,
        sparseImage,
        &sparseRequirementsCount,
        NULL);

    pSparseReqs = (VkSparseImageMemoryRequirements*)
        malloc(sparseRequirementsCount * sizeof(VkSparseImageMemoryRequirements));

    vkGetImageSparseMemoryRequirements(
        device,
        sparseImage,
        &sparseRequirementsCount,
        pSparseReqs);

    // Bind LOD level 0 and any required metadata to memory
    for (uint32_t i = 0; i < sparseRequirementsCount; ++i)
    {
        if (pSparseReqs[i].formatProperties.aspectMask &
            VK_IMAGE_ASPECT_METADATA_BIT)
        {
            // Metadata must not be combined with other aspects
            assert(pSparseReqs[i].formatProperties.aspectMask ==
                   VK_IMAGE_ASPECT_METADATA_BIT);

            if (pSparseReqs[i].formatProperties.flags &
                VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT)
            {
                VkSparseMemoryBind* pBind = &binds[bindCount];
                pBind->memorySize = pSparseReqs[i].imageMipTailSize;
                bindCount++;

                // ... Allocate memory range

                pBind->resourceOffset = pSparseReqs[i].imageMipTailOffset;
                pBind->memoryOffset = /* allocated memoryOffset */;
                pBind->memory = /* allocated memory */;
                pBind->flags = VK_SPARSE_MEMORY_BIND_METADATA_BIT;

            }
            else
            {
                // Need a mip tail region per array layer.
                for (uint32_t a = 0; a < sparseImageInfo.arrayLayers; ++a)
                {
                    VkSparseMemoryBind* pBind = &binds[bindCount];
                    pBind->memorySize = pSparseReqs[i].imageMipTailSize;
                    bindCount++;

                    // ... Allocate memory range

                    pBind->resourceOffset = pSparseReqs[i].imageMipTailOffset +
                                            (a * pSparseReqs[i].imageMipTailStride);

                    pBind->memoryOffset = /* allocated memoryOffset */;
                    pBind->memory = /* allocated memory */
                    pBind->flags = VK_SPARSE_MEMORY_BIND_METADATA_BIT;
                }
            }
        }
        else
        {
            // resource data
            VkExtent3D lod0BlockSize =
            {
                AlignedDivide(
                    sparseImageInfo.extent.width,
                    pSparseReqs[i].formatProperties.imageGranularity.width);
                AlignedDivide(
                    sparseImageInfo.extent.height,
                    pSparseReqs[i].formatProperties.imageGranularity.height);
                AlignedDivide(
                    sparseImageInfo.extent.depth,
                    pSparseReqs[i].formatProperties.imageGranularity.depth);
            }
            size_t totalBlocks =
                lod0BlockSize.width *
                lod0BlockSize.height *
                lod0BlockSize.depth;

            // Each block is the same size as the alignment requirement,
            // calculate total memory size for level 0
            VkDeviceSize lod0MemSize = totalBlocks * memoryRequirements.alignment;

            // Allocate memory for each array layer
            for (uint32_t a = 0; a < sparseImageInfo.arrayLayers; ++a)
            {
                // ... Allocate memory range

                VkSparseImageMemoryBind* pBind = &imageBinds[a];
                pBind->subresource.aspectMask = pSparseReqs[i].formatProperties.aspectMask;
                pBind->subresource.mipLevel = 0;
                pBind->subresource.arrayLayer = a;

                pBind->offset = (VkOffset3D){0, 0, 0};
                pBind->extent = sparseImageInfo.extent;
                pBind->memoryOffset = /* allocated memoryOffset */;
                pBind->memory = /* allocated memory */;
                pBind->flags = 0;
            }
        }

        free(pSparseReqs);
    }

    const VkSparseImageOpaqueMemoryBindInfo opaqueBindInfo =
    {
        sparseImage,                                // image
        bindCount,                                  // bindCount
        binds                                       // pBinds
    };

    const VkSparseImageMemoryBindInfo imageBindInfo =
    {
        sparseImage,                                // image
        sparseImageInfo.arrayLayers,                // bindCount
        imageBinds                                  // pBinds
    };

    const VkBindSparseInfo bindSparseInfo =
    {
        VK_STRUCTURE_TYPE_BIND_SPARSE_INFO,         // sType
        NULL,                                       // pNext
        ...
        1,                                          // imageOpaqueBindCount
        &opaqueBindInfo,                            // pImageOpaqueBinds
        1,                                          // imageBindCount
        &imageBindInfo,                             // pImageBinds
        ...
    };

    // vkQueueBindSparse is externally synchronized per queue object.
    AcquireQueueOwnership(queue);

    // Actually bind memory
    vkQueueBindSparse(queue, 1, &bindSparseInfo, VK_NULL_HANDLE);

    ReleaseQueueOwnership(queue);

## 32. Window System Integration (WSI)

This chapter discusses the window system integration (WSI) between the Vulkan API and the various forms of displaying the results of rendering to a user. Since the Vulkan API can be used without displaying results, WSI is provided through the use of optional Vulkan extensions. This chapter provides an overview of WSI. See the appendix for additional details of each WSI extension, including which extensions must be enabled in order to use each of the functions described in this chapter.

### 32.1. WSI Platform

A platform is an abstraction for a window system, OS, etc. Some examples include MS Windows, Android, and Wayland. The Vulkan API may be integrated in a unique manner for each platform.

The Vulkan API does not define any type of platform object. Platform-specific WSI extensions are defined, each containing platform-specific functions for using WSI. Use of these extensions is guarded by preprocessor symbols as defined in the Window System-Specific Header Control appendix.

In order for an application to be compiled to use WSI with a given platform, it must either:

- #define the appropriate preprocessor symbol prior to including the `vulkan.h` header file, or

- include `vulkan_core.h` and any native platform headers, followed by the appropriate platform-specific header.

The preprocessor symbols and platform-specific headers are defined in the Window System Extensions and Headers table.

Each platform-specific extension is an instance extension. The application must enable instance extensions with `vkCreateInstance` before using them.

### 32.2. WSI Surface

Native platform surface or window objects are abstracted by surface objects, which are represented by `VkSurfaceKHR` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkSurfaceKHR)

The `VK_KHR_surface` extension declares the `VkSurfaceKHR` object, and provides a function for destroying `VkSurfaceKHR` objects. Separate platform-specific extensions each provide a function for creating a `VkSurfaceKHR` object for the respective platform. From the application’s perspective this is an opaque handle, just like the handles of other Vulkan objects.

| Note On certain platforms, the Vulkan loader and ICDs may have conventions that treat the handle as a pointer to a structure containing the platform-specific information about the surface. This will be described in the documentation for the loader-ICD interface, and in the `vk_icd.h` header file of the LoaderAndTools source-code repository. This does not affect the loader-layer interface; layers may wrap `VkSurfaceKHR` objects.

| editing-note TODO: Consider replacing the above note editing note with a pointer to the loader spec when it exists. However, the information is not relevant to users of the API nor does it affect conformance of a Vulkan implementation to this spec.

#### 32.2.1. Android Platform

To create a `VkSurfaceKHR` object for an Android native window, call:

    VkResult vkCreateAndroidSurfaceKHR(
        VkInstance                                  instance,
        const VkAndroidSurfaceCreateInfoKHR*        pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkSurfaceKHR*                               pSurface);

- `instance` is the instance to associate the surface with.

- `pCreateInfo` is a pointer to a `VkAndroidSurfaceCreateInfoKHR` structure containing parameters affecting the creation of the surface object.

- `pAllocator` is the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation).

- `pSurface` is a pointer to a VkSurfaceKHR handle in which the created surface object is returned.

During the lifetime of a surface created using a particular ANativeWindow handle any attempts to create another surface for the same ANativeWindow and any attempts to connect to the same ANativeWindow through other platform mechanisms will fail.

| Note In particular, only one `VkSurfaceKHR` can exist at a time for a given window. Similarly, a native window cannot be used by both a `VkSurfaceKHR` and `EGLSurface` simultaneously.

If successful, `vkCreateAndroidSurfaceKHR` increments the ANativeWindow’s reference count, and `vkDestroySurfaceKHR` will decrement it.

On Android, when a swapchain’s `imageExtent` does not match the surface’s `currentExtent`, the presentable images will be scaled to the surface’s dimensions during presentation. `minImageExtent` is (1,1), and `maxImageExtent` is the maximum image size supported by the consumer. For the system compositor, `currentExtent` is the window size (i.e. the consumer’s preferred size).

Valid Usage (Implicit)

- `instance` must be a valid VkInstance handle

- `pCreateInfo` must be a valid pointer to a valid VkAndroidSurfaceCreateInfoKHR structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pSurface` must be a valid pointer to a VkSurfaceKHR handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_NATIVE_WINDOW_IN_USE_KHR`

The `VkAndroidSurfaceCreateInfoKHR` structure is defined as:

    typedef struct VkAndroidSurfaceCreateInfoKHR {
        VkStructureType                   sType;
        const void*                       pNext;
        VkAndroidSurfaceCreateFlagsKHR    flags;
        struct ANativeWindow*             window;
    } VkAndroidSurfaceCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `window` is a pointer to the ANativeWindow to associate the surface with.

Valid Usage

- `window` must point to a valid Android ANativeWindow.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_ANDROID_SURFACE_CREATE_INFO_KHR`

- `pNext` must be `NULL`

- `flags` must be `0`

To remove an unnecessary compile-time dependency, an incomplete type definition of ANativeWindow is provided in the Vulkan headers:

    struct ANativeWindow;

The actual ANativeWindow type is defined in Android NDK headers.

#### 32.2.2. Wayland Platform

To create a `VkSurfaceKHR` object for a Wayland surface, call:

    VkResult vkCreateWaylandSurfaceKHR(
        VkInstance                                  instance,
        const VkWaylandSurfaceCreateInfoKHR*        pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkSurfaceKHR*                               pSurface);

- `instance` is the instance to associate the surface with.

- `pCreateInfo` is a pointer to a VkWaylandSurfaceCreateInfoKHR structure containing parameters affecting the creation of the surface object.

- `pAllocator` is the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation).

- `pSurface` is a pointer to a VkSurfaceKHR handle in which the created surface object is returned.

Valid Usage (Implicit)

- `instance` must be a valid VkInstance handle

- `pCreateInfo` must be a valid pointer to a valid VkWaylandSurfaceCreateInfoKHR structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pSurface` must be a valid pointer to a VkSurfaceKHR handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkWaylandSurfaceCreateInfoKHR` structure is defined as:

    typedef struct VkWaylandSurfaceCreateInfoKHR {
        VkStructureType                   sType;
        const void*                       pNext;
        VkWaylandSurfaceCreateFlagsKHR    flags;
        struct wl_display*                display;
        struct wl_surface*                surface;
    } VkWaylandSurfaceCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `display` and `surface` are pointers to the Wayland `wl_display` and `wl_surface` to associate the surface with.

Valid Usage

- `display` must point to a valid Wayland `wl_display`.

- `surface` must point to a valid Wayland `wl_surface`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_WAYLAND_SURFACE_CREATE_INFO_KHR`

- `pNext` must be `NULL`

- `flags` must be `0`

On Wayland, `currentExtent` is the special value (0xFFFFFFFF, 0xFFFFFFFF), indicating that the surface size will be determined by the extent of a swapchain targeting the surface. Whatever the application sets a swapchain’s `imageExtent` to will be the size of the window, after the first image is presented. `minImageExtent` is (1,1), and `maxImageExtent` is the maximum supported surface size. Any calls to vkGetPhysicalDeviceSurfacePresentModesKHR on a surface created with `vkCreateWaylandSurfaceKHR` are required to return `VK_PRESENT_MODE_MAILBOX_KHR` as one of the valid present modes.

Some Vulkan functions may send protocol over the specified `wl_display` connection when using a swapchain or presentable images created from a `VkSurfaceKHR` referring to a `wl_surface`. Applications must therefore ensure that both the `wl_display` and the `wl_surface` remain valid for the lifetime of any `VkSwapchainKHR` objects created from a particular `wl_display` and `wl_surface`. Also, calling vkQueuePresentKHR will result in Vulkan sending `wl_surface.commit` requests to the underlying `wl_surface` of each `VkSwapchainKHR` objects referenced by `pPresentInfo`. If the swapchain is created with a present mode of `VK_PRESENT_MODE_MAILBOX_KHR` or `VK_PRESENT_MODE_IMMEDIATE_KHR`, then the corresponding `wl_surface.attach`, `wl_surface.damage`, and `wl_surface.commit` request must be issued by the implementation during the call to vkQueuePresentKHR and must not be issued by the implementation outside of vkQueuePresentKHR. This ensures that any Wayland requests sent by the client after the call to vkQueuePresentKHR returns will be received by the compositor after the `wl_surface.commit`. Regardless of the mode of swapchain creation, a new `wl_event_queue` must be created for each successful vkCreateWaylandSurfaceKHR call, and every Wayland object created by the implementation must be assigned to this event queue. If the platform provides Wayland 1.11 or greater, this must be implemented by the use of Wayland proxy object wrappers, to avoid race conditions.

If the application wishes to synchronize any window changes with a particular frame, such requests must be sent to the Wayland display server prior to calling vkQueuePresentKHR. For full control over interactions between Vulkan rendering and other Wayland protocol requests and events, a present mode of `VK_PRESENT_MODE_MAILBOX_KHR` should be used.

#### 32.2.3. Win32 Platform

To create a `VkSurfaceKHR` object for a Win32 window, call:

    VkResult vkCreateWin32SurfaceKHR(
        VkInstance                                  instance,
        const VkWin32SurfaceCreateInfoKHR*          pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkSurfaceKHR*                               pSurface);

- `instance` is the instance to associate the surface with.

- `pCreateInfo` is a pointer to a `VkWin32SurfaceCreateInfoKHR` structure containing parameters affecting the creation of the surface object.

- `pAllocator` is the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation).

- `pSurface` is a pointer to a VkSurfaceKHR handle in which the created surface object is returned.

Valid Usage (Implicit)

- `instance` must be a valid VkInstance handle

- `pCreateInfo` must be a valid pointer to a valid VkWin32SurfaceCreateInfoKHR structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pSurface` must be a valid pointer to a VkSurfaceKHR handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkWin32SurfaceCreateInfoKHR` structure is defined as:

    typedef struct VkWin32SurfaceCreateInfoKHR {
        VkStructureType                 sType;
        const void*                     pNext;
        VkWin32SurfaceCreateFlagsKHR    flags;
        HINSTANCE                       hinstance;
        HWND                            hwnd;
    } VkWin32SurfaceCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `hinstance` is the Win32 `HINSTANCE` for the window to associate the surface with.

- `hwnd` is the Win32 `HWND` for the window to associate the surface with.

Valid Usage

- `hinstance` must be a valid Win32 `HINSTANCE`.

- `hwnd` must be a valid Win32 `HWND`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_WIN32_SURFACE_CREATE_INFO_KHR`

- `pNext` must be `NULL`

- `flags` must be `0`

With Win32, `minImageExtent`, `maxImageExtent`, and `currentExtent` must always equal the window size.

The `currentExtent` of a Win32 surface must have both `width` and `height` greater than 0, or both of them 0.

| Note Due to above restrictions, it is only possible to create a new swapchain on this platform with `imageExtent` being equal to the current size of the window. The window size may become (0, 0) on this platform (e.g. when the window is minimized), and so a swapchain cannot be created until the size changes.

    typedef VkFlags VkWin32SurfaceCreateFlagsKHR;

`VkWin32SurfaceCreateFlagsKHR` is a bitmask type for setting a mask, but is currently reserved for future use.

#### 32.2.4. XCB Platform

To create a `VkSurfaceKHR` object for an X11 window, using the XCB client-side library, call:

    VkResult vkCreateXcbSurfaceKHR(
        VkInstance                                  instance,
        const VkXcbSurfaceCreateInfoKHR*            pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkSurfaceKHR*                               pSurface);

- `instance` is the instance to associate the surface with.

- `pCreateInfo` is a pointer to a `VkXcbSurfaceCreateInfoKHR` structure containing parameters affecting the creation of the surface object.

- `pAllocator` is the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation).

- `pSurface` is a pointer to a VkSurfaceKHR handle in which the created surface object is returned.

Valid Usage (Implicit)

- `instance` must be a valid VkInstance handle

- `pCreateInfo` must be a valid pointer to a valid VkXcbSurfaceCreateInfoKHR structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pSurface` must be a valid pointer to a VkSurfaceKHR handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkXcbSurfaceCreateInfoKHR` structure is defined as:

    typedef struct VkXcbSurfaceCreateInfoKHR {
        VkStructureType               sType;
        const void*                   pNext;
        VkXcbSurfaceCreateFlagsKHR    flags;
        xcb_connection_t*             connection;
        xcb_window_t                  window;
    } VkXcbSurfaceCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `connection` is a pointer to an `xcb_connection_t` to the X server.

- `window` is the `xcb_window_t` for the X11 window to associate the surface with.

Valid Usage

- `connection` must point to a valid X11 `xcb_connection_t`.

- `window` must be a valid X11 `xcb_window_t`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_XCB_SURFACE_CREATE_INFO_KHR`

- `pNext` must be `NULL`

- `flags` must be `0`

With Xcb, `minImageExtent`, `maxImageExtent`, and `currentExtent` must always equal the window size.

The `currentExtent` of an Xcb surface must have both `width` and `height` greater than 0, or both of them 0.

| Note Due to above restrictions, it is only possible to create a new swapchain on this platform with `imageExtent` being equal to the current size of the window. The window size may become (0, 0) on this platform (e.g. when the window is minimized), and so a swapchain cannot be created until the size changes.

Some Vulkan functions may send protocol over the specified xcb connection when using a swapchain or presentable images created from a VkSurfaceKHR referring to an xcb window. Applications must therefore ensure the xcb connection is available to Vulkan for the duration of any functions that manipulate such swapchains or their presentable images, and any functions that build or queue command buffers that operate on such presentable images. Specifically, applications using Vulkan with xcb-based swapchains must

- Avoid holding a server grab on an xcb connection while waiting for Vulkan operations to complete using a swapchain derived from a different xcb connection referring to the same X server instance. Failing to do so may result in deadlock.

#### 32.2.5. Xlib Platform

To create a `VkSurfaceKHR` object for an X11 window, using the Xlib client-side library, call:

    VkResult vkCreateXlibSurfaceKHR(
        VkInstance                                  instance,
        const VkXlibSurfaceCreateInfoKHR*           pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkSurfaceKHR*                               pSurface);

- `instance` is the instance to associate the surface with.

- `pCreateInfo` is a pointer to a `VkXlibSurfaceCreateInfoKHR` structure containing the parameters affecting the creation of the surface object.

- `pAllocator` is the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation).

- `pSurface` is a pointer to a VkSurfaceKHR handle in which the created surface object is returned.

Valid Usage (Implicit)

- `instance` must be a valid VkInstance handle

- `pCreateInfo` must be a valid pointer to a valid VkXlibSurfaceCreateInfoKHR structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pSurface` must be a valid pointer to a VkSurfaceKHR handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkXlibSurfaceCreateInfoKHR` structure is defined as:

    typedef struct VkXlibSurfaceCreateInfoKHR {
        VkStructureType                sType;
        const void*                    pNext;
        VkXlibSurfaceCreateFlagsKHR    flags;
        Display*                       dpy;
        Window                         window;
    } VkXlibSurfaceCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `dpy` is a pointer to an Xlib `Display` connection to the X server.

- `window` is an Xlib `Window` to associate the surface with.

Valid Usage

- `dpy` must point to a valid Xlib `Display`.

- `window` must be a valid Xlib `Window`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_XLIB_SURFACE_CREATE_INFO_KHR`

- `pNext` must be `NULL`

- `flags` must be `0`

With Xlib, `minImageExtent`, `maxImageExtent`, and `currentExtent` must always equal the window size.

The `currentExtent` of an Xlib surface must have both `width` and `height` greater than 0, or both of them 0.

| Note Due to above restrictions, it is only possible to create a new swapchain on this platform with `imageExtent` being equal to the current size of the window. The window size may become (0, 0) on this platform (e.g. when the window is minimized), and so a swapchain cannot be created until the size changes.

Some Vulkan functions may send protocol over the specified Xlib `Display` connection when using a swapchain or presentable images created from a VkSurfaceKHR referring to an Xlib window. Applications must therefore ensure the display connection is available to Vulkan for the duration of any functions that manipulate such swapchains or their presentable images, and any functions that build or queue command buffers that operate on such presentable images. Specifically, applications using Vulkan with Xlib-based swapchains must

- Avoid holding a server grab on a display connection while waiting for Vulkan operations to complete using a swapchain derived from a different display connection referring to the same X server instance. Failing to do so may result in deadlock.

Some implementations may require threads to implement some presentation modes so applications must call `XInitThreads`() before calling any other Xlib functions.

#### 32.2.6. Fuchsia Platform

To create a `VkSurfaceKHR` object for a Fuchsia ImagePipe, call:

    VkResult vkCreateImagePipeSurfaceFUCHSIA(
        VkInstance                                  instance,
        const VkImagePipeSurfaceCreateInfoFUCHSIA*  pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkSurfaceKHR*                               pSurface);

- `instance` is the instance to associate with the surface.

- `pCreateInfo` is a pointer to a VkImagePipeSurfaceCreateInfoFUCHSIA structure containing parameters affecting the creation of the surface object.

- `pAllocator` is the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation).

- `pSurface` is a pointer to a VkSurfaceKHR handle in which the created surface object is returned.

Valid Usage (Implicit)

- `instance` must be a valid VkInstance handle

- `pCreateInfo` must be a valid pointer to a valid VkImagePipeSurfaceCreateInfoFUCHSIA structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pSurface` must be a valid pointer to a VkSurfaceKHR handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkImagePipeSurfaceCreateInfoFUCHSIA` structure is defined as:

    typedef struct VkImagePipeSurfaceCreateInfoFUCHSIA {
        VkStructureType                         sType;
        const void*                             pNext;
        VkImagePipeSurfaceCreateFlagsFUCHSIA    flags;
        zx_handle_t                             imagePipeHandle;
    } VkImagePipeSurfaceCreateInfoFUCHSIA;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `imagePipeHandle` is a `zx_handle_t` referring to the ImagePipe to associate with the surface.

Valid Usage

- `imagePipeHandle` must be a valid `zx_handle_t`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMAGEPIPE_SURFACE_CREATE_INFO_FUCHSIA`

- `pNext` must be `NULL`

- `flags` must be `0`

On Fuchsia, the surface `currentExtent` is the special value (0xFFFFFFFF, 0xFFFFFFFF), indicating that the surface size will be determined by the extent of a swapchain targeting the surface.

#### 32.2.7. Google Games Platform

To create a `VkSurfaceKHR` object for a Google Games Platform stream descriptor, call:

    VkResult vkCreateStreamDescriptorSurfaceGGP(
        VkInstance                                  instance,
        const VkStreamDescriptorSurfaceCreateInfoGGP* pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkSurfaceKHR*                               pSurface);

- `instance` is the instance to associate with the surface.

- `pCreateInfo` is a pointer to a `VkStreamDescriptorSurfaceCreateInfoGGP` structure containing parameters that affect the creation of the surface object.

- `pAllocator` is the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation).

- `pSurface` is a pointer to a VkSurfaceKHR handle in which the created surface object is returned.

Valid Usage (Implicit)

- `instance` must be a valid VkInstance handle

- `pCreateInfo` must be a valid pointer to a valid VkStreamDescriptorSurfaceCreateInfoGGP structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pSurface` must be a valid pointer to a VkSurfaceKHR handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_NATIVE_WINDOW_IN_USE_KHR`

The `VkStreamDescriptorSurfaceCreateInfoGGP` structure is defined as:

    typedef struct VkStreamDescriptorSurfaceCreateInfoGGP {
        VkStructureType                            sType;
        const void*                                pNext;
        VkStreamDescriptorSurfaceCreateFlagsGGP    flags;
        GgpStreamDescriptor                        streamDescriptor;
    } VkStreamDescriptorSurfaceCreateInfoGGP;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `streamDescriptor` is a `GgpStreamDescriptor` referring to the GGP stream descriptor to associate with the surface.

Valid Usage

- `streamDescriptor` must be a valid `GgpStreamDescriptor`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_STREAM_DESCRIPTOR_SURFACE_CREATE_INFO_GGP`

- `pNext` must be `NULL`

- `flags` must be `0`

On Google Games Platform, the surface extents are dynamic. The `minImageExtent` will never be greater than 1080p and the `maxImageExtent` will never be less than 1080p. The `currentExtent` will reflect the current optimal resolution.

Applications are expected to choose an appropriate size for the swapchain’s `imageExtent`, within the bounds of the surface. Using the surface’s `currentExtent` will offer the best performance and quality. When a swapchain’s `imageExtent` does not match the surface’s `currentExtent`, the presentable images are scaled to the surface’s dimensions during presentation if possible and `VK_SUBOPTIMAL_KHR` is returned, otherwise presentation fails with `VK_ERROR_OUT_OF_DATE_KHR`.

#### 32.2.8. iOS Platform

To create a `VkSurfaceKHR` object for an iOS `UIView`, call:

    VkResult vkCreateIOSSurfaceMVK(
        VkInstance                                  instance,
        const VkIOSSurfaceCreateInfoMVK*            pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkSurfaceKHR*                               pSurface);

- `instance` is the instance with which to associate the surface.

- `pCreateInfo` is a pointer to a VkIOSSurfaceCreateInfoMVK structure containing parameters affecting the creation of the surface object.

- `pAllocator` is the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation).

- `pSurface` is a pointer to a VkSurfaceKHR handle in which the created surface object is returned.

Valid Usage (Implicit)

- `instance` must be a valid VkInstance handle

- `pCreateInfo` must be a valid pointer to a valid VkIOSSurfaceCreateInfoMVK structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pSurface` must be a valid pointer to a VkSurfaceKHR handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_NATIVE_WINDOW_IN_USE_KHR`

The VkIOSSurfaceCreateInfoMVK structure is defined as:

    typedef struct VkIOSSurfaceCreateInfoMVK {
        VkStructureType               sType;
        const void*                   pNext;
        VkIOSSurfaceCreateFlagsMVK    flags;
        const void*                   pView;
    } VkIOSSurfaceCreateInfoMVK;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `pView` is a reference to a `UIView` object which will display this surface. This `UIView` must be backed by a `CALayer` instance of type CAMetalLayer.

Valid Usage

- `pView` must be a valid `UIView` and must be backed by a `CALayer` instance of type CAMetalLayer.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IOS_SURFACE_CREATE_INFO_MVK`

- `pNext` must be `NULL`

- `flags` must be `0`

#### 32.2.9. macOS Platform

To create a `VkSurfaceKHR` object for a macOS `NSView`, call:

    VkResult vkCreateMacOSSurfaceMVK(
        VkInstance                                  instance,
        const VkMacOSSurfaceCreateInfoMVK*          pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkSurfaceKHR*                               pSurface);

- `instance` is the instance with which to associate the surface.

- `pCreateInfo` is a pointer to a VkMacOSSurfaceCreateInfoMVK structure containing parameters affecting the creation of the surface object.

- `pAllocator` is the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation).

- `pSurface` is a pointer to a VkSurfaceKHR handle in which the created surface object is returned.

Valid Usage (Implicit)

- `instance` must be a valid VkInstance handle

- `pCreateInfo` must be a valid pointer to a valid VkMacOSSurfaceCreateInfoMVK structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pSurface` must be a valid pointer to a VkSurfaceKHR handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_NATIVE_WINDOW_IN_USE_KHR`

The VkMacOSSurfaceCreateInfoMVK structure is defined as:

    typedef struct VkMacOSSurfaceCreateInfoMVK {
        VkStructureType                 sType;
        const void*                     pNext;
        VkMacOSSurfaceCreateFlagsMVK    flags;
        const void*                     pView;
    } VkMacOSSurfaceCreateInfoMVK;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `pView` is a reference to a `NSView` object which will display this surface. This `NSView` must be backed by a `CALayer` instance of type CAMetalLayer.

Valid Usage

- `pView` must be a valid `NSView` and must be backed by a `CALayer` instance of type CAMetalLayer.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_MACOS_SURFACE_CREATE_INFO_MVK`

- `pNext` must be `NULL`

- `flags` must be `0`

#### 32.2.10. VI Platform

To create a `VkSurfaceKHR` object for an `nn`::`vi`::`Layer`, query the layer’s native handle using `nn`::`vi`::`GetNativeWindow`, and then call:

    VkResult vkCreateViSurfaceNN(
        VkInstance                                  instance,
        const VkViSurfaceCreateInfoNN*              pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkSurfaceKHR*                               pSurface);

- `instance` is the instance with which to associate the surface.

- `pCreateInfo` is a pointer to a `VkViSurfaceCreateInfoNN` structure containing parameters affecting the creation of the surface object.

- `pAllocator` is the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation).

- `pSurface` is a pointer to a VkSurfaceKHR handle in which the created surface object is returned.

During the lifetime of a surface created using a particular `nn`::`vi`::`NativeWindowHandle`, applications must not attempt to create another surface for the same `nn`::`vi`::`Layer` or attempt to connect to the same `nn`::`vi`::`Layer` through other platform mechanisms.

If the native window is created with a specified size, `currentExtent` will reflect that size. In this case, applications should use the same size for the swapchain’s `imageExtent`. Otherwise, the `currentExtent` will have the special value (0xFFFFFFFF, 0xFFFFFFFF), indicating that applications are expected to choose an appropriate size for the swapchain’s `imageExtent` (e.g., by matching the result of a call to `nn`::`vi`::`GetDisplayResolution`).

Valid Usage (Implicit)

- `instance` must be a valid VkInstance handle

- `pCreateInfo` must be a valid pointer to a valid VkViSurfaceCreateInfoNN structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pSurface` must be a valid pointer to a VkSurfaceKHR handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_NATIVE_WINDOW_IN_USE_KHR`

The `VkViSurfaceCreateInfoNN` structure is defined as:

    typedef struct VkViSurfaceCreateInfoNN {
        VkStructureType             sType;
        const void*                 pNext;
        VkViSurfaceCreateFlagsNN    flags;
        void*                       window;
    } VkViSurfaceCreateInfoNN;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `window` is the `nn`::`vi`::`NativeWindowHandle` for the `nn`::`vi`::`Layer` with which to associate the surface.

Valid Usage

- `window` must be a valid `nn`::`vi`::`NativeWindowHandle`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_VI_SURFACE_CREATE_INFO_NN`

- `pNext` must be `NULL`

- `flags` must be `0`

#### 32.2.11. Metal Platform

To create a `VkSurfaceKHR` object for a CAMetalLayer, call:

    VkResult vkCreateMetalSurfaceEXT(
        VkInstance                                  instance,
        const VkMetalSurfaceCreateInfoEXT*          pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkSurfaceKHR*                               pSurface);

- `instance` is the instance with which to associate the surface.

- `pCreateInfo` is a pointer to a VkMetalSurfaceCreateInfoEXT structure specifying parameters affecting the creation of the surface object.

- `pAllocator` is the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation).

- `pSurface` is a pointer to a `VkSurfaceKHR` handle in which the created surface object is returned.

Valid Usage (Implicit)

- `instance` must be a valid VkInstance handle

- `pCreateInfo` must be a valid pointer to a valid VkMetalSurfaceCreateInfoEXT structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pSurface` must be a valid pointer to a VkSurfaceKHR handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_NATIVE_WINDOW_IN_USE_KHR`

The VkMetalSurfaceCreateInfoEXT structure is defined as:

    typedef struct VkMetalSurfaceCreateInfoEXT {
        VkStructureType                 sType;
        const void*                     pNext;
        VkMetalSurfaceCreateFlagsEXT    flags;
        const CAMetalLayer*             pLayer;
    } VkMetalSurfaceCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

- `pLayer` is a reference to a CAMetalLayer object representing a renderable surface.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_METAL_SURFACE_CREATE_INFO_EXT`

- `pNext` must be `NULL`

- `flags` must be `0`

To remove an unnecessary compile-time dependency, an incomplete type definition of CAMetalLayer is provided in the Vulkan headers:

    #ifdef __OBJC__
    @class CAMetalLayer;
    #else
    typedef void CAMetalLayer;
    #endif

The actual CAMetalLayer type is defined in the QuartzCore framework.

#### 32.2.12. Platform-Independent Information

Once created, `VkSurfaceKHR` objects can be used in this and other extensions, in particular the `VK_KHR_swapchain` extension.

Several WSI functions return `VK_ERROR_SURFACE_LOST_KHR` if the surface becomes no longer available. After such an error, the surface (and any child swapchain, if one exists) should be destroyed, as there is no way to restore them to a not-lost state. Applications may attempt to create a new `VkSurfaceKHR` using the same native platform window object, but whether such re-creation will succeed is platform-dependent and may depend on the reason the surface became unavailable. A lost surface does not otherwise cause devices to be lost.

To destroy a `VkSurfaceKHR` object, call:

    void vkDestroySurfaceKHR(
        VkInstance                                  instance,
        VkSurfaceKHR                                surface,
        const VkAllocationCallbacks*                pAllocator);

- `instance` is the instance used to create the surface.

- `surface` is the surface to destroy.

- `pAllocator` is the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation).

Destroying a `VkSurfaceKHR` merely severs the connection between Vulkan and the native surface, and does not imply destroying the native surface, closing a window, or similar behavior.

Valid Usage

- All `VkSwapchainKHR` objects created for `surface` must have been destroyed prior to destroying `surface`

- If `VkAllocationCallbacks` were provided when `surface` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `surface` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `instance` must be a valid VkInstance handle

- If `surface` is not VK_NULL_HANDLE, `surface` must be a valid VkSurfaceKHR handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- If `surface` is a valid handle, it must have been created, allocated, or retrieved from `instance`

Host Synchronization

- Host access to `surface` must be externally synchronized

### 32.3. Presenting Directly to Display Devices

In some environments applications can also present Vulkan rendering directly to display devices without using an intermediate windowing system. This can be useful for embedded applications, or implementing the rendering/presentation backend of a windowing system using Vulkan. The `VK_KHR_display` extension provides the functionality necessary to enumerate display devices and create `VkSurfaceKHR` objects that target displays.

#### 32.3.1. Display Enumeration

Displays are represented by `VkDisplayKHR` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkDisplayKHR)

Various functions are provided for enumerating the available display devices present on a Vulkan physical device. To query information about the available displays, call:

    VkResult vkGetPhysicalDeviceDisplayPropertiesKHR(
        VkPhysicalDevice                            physicalDevice,
        uint32_t*                                   pPropertyCount,
        VkDisplayPropertiesKHR*                     pProperties);

- `physicalDevice` is a physical device.

- `pPropertyCount` is a pointer to an integer related to the number of display devices available or queried, as described below.

- `pProperties` is either `NULL` or a pointer to an array of `VkDisplayPropertiesKHR` structures.

If `pProperties` is `NULL`, then the number of display devices available for `physicalDevice` is returned in `pPropertyCount`. Otherwise, `pPropertyCount` must point to a variable set by the user to the number of elements in the `pProperties` array, and on return the variable is overwritten with the number of structures actually written to `pProperties`. If the value of `pPropertyCount` is less than the number of display devices for `physicalDevice`, at most `pPropertyCount` structures will be written. If `pPropertyCount` is smaller than the number of display devices available for `physicalDevice`, `VK_INCOMPLETE` will be returned instead of `VK_SUCCESS` to indicate that not all the available values were returned.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pPropertyCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pPropertyCount` is not `0`, and `pProperties` is not `NULL`, `pProperties` must be a valid pointer to an array of `pPropertyCount` VkDisplayPropertiesKHR structures

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkDisplayPropertiesKHR` structure is defined as:

    typedef struct VkDisplayPropertiesKHR {
        VkDisplayKHR                  display;
        const char*                   displayName;
        VkExtent2D                    physicalDimensions;
        VkExtent2D                    physicalResolution;
        VkSurfaceTransformFlagsKHR    supportedTransforms;
        VkBool32                      planeReorderPossible;
        VkBool32                      persistentContent;
    } VkDisplayPropertiesKHR;

- `display` is a handle that is used to refer to the display described here. This handle will be valid for the lifetime of the Vulkan instance.

- `displayName` is a pointer to a null-terminated UTF-8 string containing the name of the display. Generally, this will be the name provided by the display’s EDID. It can be `NULL` if no suitable name is available. If not `NULL`, the memory it points to must remain accessible as long as `display` is valid.

- `physicalDimensions` describes the physical width and height of the visible portion of the display, in millimeters.

- `physicalResolution` describes the physical, native, or preferred resolution of the display.

| Note For devices which have no natural value to return here, implementations should return the maximum resolution supported.

- `supportedTransforms` is a bitmask of VkSurfaceTransformFlagBitsKHR describing which transforms are supported by this display.

- `planeReorderPossible` tells whether the planes on this display can have their z order changed. If this is `VK_TRUE`, the application can re-arrange the planes on this display in any order relative to each other.

- `persistentContent` tells whether the display supports self-refresh/internal buffering. If this is true, the application can submit persistent present operations on swapchains created against this display.

| Note Persistent presents may have higher latency, and may use less power when the screen content is updated infrequently, or when only a portion of the screen needs to be updated in most frames.

To query information about the available displays, call:

    VkResult vkGetPhysicalDeviceDisplayProperties2KHR(
        VkPhysicalDevice                            physicalDevice,
        uint32_t*                                   pPropertyCount,
        VkDisplayProperties2KHR*                    pProperties);

- `physicalDevice` is a physical device.

- `pPropertyCount` is a pointer to an integer related to the number of display devices available or queried, as described below.

- `pProperties` is either `NULL` or a pointer to an array of `VkDisplayProperties2KHR` structures.

`vkGetPhysicalDeviceDisplayProperties2KHR` behaves similarly to vkGetPhysicalDeviceDisplayPropertiesKHR, with the ability to return extended information via chained output structures.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pPropertyCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pPropertyCount` is not `0`, and `pProperties` is not `NULL`, `pProperties` must be a valid pointer to an array of `pPropertyCount` VkDisplayProperties2KHR structures

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkDisplayProperties2KHR` structure is defined as:

    typedef struct VkDisplayProperties2KHR {
        VkStructureType           sType;
        void*                     pNext;
        VkDisplayPropertiesKHR    displayProperties;
    } VkDisplayProperties2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `displayProperties` is a VkDisplayPropertiesKHR structure.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DISPLAY_PROPERTIES_2_KHR`

- `pNext` must be `NULL`

##### Acquiring and Releasing Displays

On some platforms, access to displays is limited to a single process or native driver instance. On such platforms, some or all of the displays may not be available to Vulkan if they are already in use by a native windowing system or other application.

To acquire permission to directly access a display in Vulkan from an X11 server, call:

    VkResult vkAcquireXlibDisplayEXT(
        VkPhysicalDevice                            physicalDevice,
        Display*                                    dpy,
        VkDisplayKHR                                display);

- `physicalDevice` The physical device the display is on.

- `dpy` A connection to the X11 server that currently owns `display`.

- `display` The display the caller wishes to control in Vulkan.

All permissions necessary to control the display are granted to the Vulkan instance associated with `physicalDevice` until the display is released or the X11 connection specified by `dpy` is terminated. Permission to access the display may be temporarily revoked during periods when the X11 server from which control was acquired itself loses access to `display`. During such periods, operations which require access to the display must fail with an approriate error code. If the X11 server associated with `dpy` does not own `display`, or if permission to access it has already been acquired by another entity, the call must return the error code `VK_ERROR_INITIALIZATION_FAILED`.

| Note One example of when an X11 server loses access to a display is when it loses ownership of its virtual terminal.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `dpy` must be a valid pointer to a `Display` value

- `display` must be a valid VkDisplayKHR handle

- `display` must have been created, allocated, or retrieved from `physicalDevice`

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_INITIALIZATION_FAILED`

When acquiring displays from an X11 server, an application may also wish to enumerate and identify them using a native handle rather than a `VkDisplayKHR` handle. To determine the `VkDisplayKHR` handle corresponding to an X11 RandR Output, call:

    VkResult vkGetRandROutputDisplayEXT(
        VkPhysicalDevice                            physicalDevice,
        Display*                                    dpy,
        RROutput                                    rrOutput,
        VkDisplayKHR*                               pDisplay);

- `physicalDevice` The physical device to query the display handle on.

- `dpy` A connection to the X11 server from which `rrOutput` was queried.

- `rrOutput` An X11 RandR output ID.

- `pDisplay` The corresponding VkDisplayKHR handle will be returned here.

If there is no VkDisplayKHR corresponding to `rrOutput` on `physicalDevice`, VK_NULL_HANDLE must be returned in `pDisplay`.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `dpy` must be a valid pointer to a `Display` value

- `pDisplay` must be a valid pointer to a VkDisplayKHR handle

Return Codes

Success

  - `VK_SUCCESS`

To release a previously acquired display, call:

    VkResult vkReleaseDisplayEXT(
        VkPhysicalDevice                            physicalDevice,
        VkDisplayKHR                                display);

- `physicalDevice` The physical device the display is on.

- `display` The display to release control of.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `display` must be a valid VkDisplayKHR handle

- `display` must have been created, allocated, or retrieved from `physicalDevice`

Return Codes

Success

  - `VK_SUCCESS`

##### Display Planes

Images are presented to individual planes on a display. Devices must support at least one plane on each display. Planes can be stacked and blended to composite multiple images on one display. Devices may support only a fixed stacking order and fixed mapping between planes and displays, or they may allow arbitrary application specified stacking orders and mappings between planes and displays. To query the properties of device display planes, call:

    VkResult vkGetPhysicalDeviceDisplayPlanePropertiesKHR(
        VkPhysicalDevice                            physicalDevice,
        uint32_t*                                   pPropertyCount,
        VkDisplayPlanePropertiesKHR*                pProperties);

- `physicalDevice` is a physical device.

- `pPropertyCount` is a pointer to an integer related to the number of display planes available or queried, as described below.

- `pProperties` is either `NULL` or a pointer to an array of `VkDisplayPlanePropertiesKHR` structures.

If `pProperties` is `NULL`, then the number of display planes available for `physicalDevice` is returned in `pPropertyCount`. Otherwise, `pPropertyCount` must point to a variable set by the user to the number of elements in the `pProperties` array, and on return the variable is overwritten with the number of structures actually written to `pProperties`. If the value of `pPropertyCount` is less than the number of display planes for `physicalDevice`, at most `pPropertyCount` structures will be written.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pPropertyCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pPropertyCount` is not `0`, and `pProperties` is not `NULL`, `pProperties` must be a valid pointer to an array of `pPropertyCount` VkDisplayPlanePropertiesKHR structures

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkDisplayPlanePropertiesKHR` structure is defined as:

    typedef struct VkDisplayPlanePropertiesKHR {
        VkDisplayKHR    currentDisplay;
        uint32_t        currentStackIndex;
    } VkDisplayPlanePropertiesKHR;

- `currentDisplay` is the handle of the display the plane is currently associated with. If the plane is not currently attached to any displays, this will be VK_NULL_HANDLE.

- `currentStackIndex` is the current z-order of the plane. This will be between 0 and the value returned by `vkGetPhysicalDeviceDisplayPlanePropertiesKHR` in `pPropertyCount`.

To query the properties of a device’s display planes, call:

    VkResult vkGetPhysicalDeviceDisplayPlaneProperties2KHR(
        VkPhysicalDevice                            physicalDevice,
        uint32_t*                                   pPropertyCount,
        VkDisplayPlaneProperties2KHR*               pProperties);

- `physicalDevice` is a physical device.

- `pPropertyCount` is a pointer to an integer related to the number of display planes available or queried, as described below.

- `pProperties` is either `NULL` or a pointer to an array of `VkDisplayPlaneProperties2KHR` structures.

`vkGetPhysicalDeviceDisplayPlaneProperties2KHR` behaves similarly to vkGetPhysicalDeviceDisplayPlanePropertiesKHR, with the ability to return extended information via chained output structures.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pPropertyCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pPropertyCount` is not `0`, and `pProperties` is not `NULL`, `pProperties` must be a valid pointer to an array of `pPropertyCount` VkDisplayPlaneProperties2KHR structures

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkDisplayPlaneProperties2KHR` structure is defined as:

    typedef struct VkDisplayPlaneProperties2KHR {
        VkStructureType                sType;
        void*                          pNext;
        VkDisplayPlanePropertiesKHR    displayPlaneProperties;
    } VkDisplayPlaneProperties2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `displayPlaneProperties` is a VkDisplayPlanePropertiesKHR structure.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DISPLAY_PLANE_PROPERTIES_2_KHR`

- `pNext` must be `NULL`

To determine which displays a plane is usable with, call

    VkResult vkGetDisplayPlaneSupportedDisplaysKHR(
        VkPhysicalDevice                            physicalDevice,
        uint32_t                                    planeIndex,
        uint32_t*                                   pDisplayCount,
        VkDisplayKHR*                               pDisplays);

- `physicalDevice` is a physical device.

- `planeIndex` is the plane which the application wishes to use, and must be in the range [0, physical device plane count - 1].

- `pDisplayCount` is a pointer to an integer related to the number of displays available or queried, as described below.

- `pDisplays` is either `NULL` or a pointer to an array of `VkDisplayKHR` handles.

If `pDisplays` is `NULL`, then the number of displays usable with the specified `planeIndex` for `physicalDevice` is returned in `pDisplayCount`. Otherwise, `pDisplayCount` must point to a variable set by the user to the number of elements in the `pDisplays` array, and on return the variable is overwritten with the number of handles actually written to `pDisplays`. If the value of `pDisplayCount` is less than the number of display planes for `physicalDevice`, at most `pDisplayCount` handles will be written. If `pDisplayCount` is smaller than the number of displays usable with the specified `planeIndex` for `physicalDevice`, `VK_INCOMPLETE` will be returned instead of `VK_SUCCESS` to indicate that not all the available values were returned.

Valid Usage

- `planeIndex` must be less than the number of display planes supported by the device as determined by calling `vkGetPhysicalDeviceDisplayPlanePropertiesKHR`

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pDisplayCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pDisplayCount` is not `0`, and `pDisplays` is not `NULL`, `pDisplays` must be a valid pointer to an array of `pDisplayCount` VkDisplayKHR handles

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

Additional properties of displays are queried using specialized query functions.

##### Display Modes

Display modes are represented by `VkDisplayModeKHR` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkDisplayModeKHR)

Each display has one or more supported modes associated with it by default. These built-in modes are queried by calling:

    VkResult vkGetDisplayModePropertiesKHR(
        VkPhysicalDevice                            physicalDevice,
        VkDisplayKHR                                display,
        uint32_t*                                   pPropertyCount,
        VkDisplayModePropertiesKHR*                 pProperties);

- `physicalDevice` is the physical device associated with `display`.

- `display` is the display to query.

- `pPropertyCount` is a pointer to an integer related to the number of display modes available or queried, as described below.

- `pProperties` is either `NULL` or a pointer to an array of `VkDisplayModePropertiesKHR` structures.

If `pProperties` is `NULL`, then the number of display modes available on the specified `display` for `physicalDevice` is returned in `pPropertyCount`. Otherwise, `pPropertyCount` must point to a variable set by the user to the number of elements in the `pProperties` array, and on return the variable is overwritten with the number of structures actually written to `pProperties`. If the value of `pPropertyCount` is less than the number of display modes for `physicalDevice`, at most `pPropertyCount` structures will be written. If `pPropertyCount` is smaller than the number of display modes available on the specified `display` for `physicalDevice`, `VK_INCOMPLETE` will be returned instead of `VK_SUCCESS` to indicate that not all the available values were returned.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `display` must be a valid VkDisplayKHR handle

- `pPropertyCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pPropertyCount` is not `0`, and `pProperties` is not `NULL`, `pProperties` must be a valid pointer to an array of `pPropertyCount` VkDisplayModePropertiesKHR structures

- `display` must have been created, allocated, or retrieved from `physicalDevice`

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkDisplayModePropertiesKHR` structure is defined as:

    typedef struct VkDisplayModePropertiesKHR {
        VkDisplayModeKHR              displayMode;
        VkDisplayModeParametersKHR    parameters;
    } VkDisplayModePropertiesKHR;

- `displayMode` is a handle to the display mode described in this structure. This handle will be valid for the lifetime of the Vulkan instance.

- `parameters` is a VkDisplayModeParametersKHR structure describing the display parameters associated with `displayMode`.

    typedef VkFlags VkDisplayModeCreateFlagsKHR;

`VkDisplayModeCreateFlagsKHR` is a bitmask type for setting a mask, but is currently reserved for future use.

To query the properties of a device’s built-in display modes, call:

    VkResult vkGetDisplayModeProperties2KHR(
        VkPhysicalDevice                            physicalDevice,
        VkDisplayKHR                                display,
        uint32_t*                                   pPropertyCount,
        VkDisplayModeProperties2KHR*                pProperties);

- `physicalDevice` is the physical device associated with `display`.

- `display` is the display to query.

- `pPropertyCount` is a pointer to an integer related to the number of display modes available or queried, as described below.

- `pProperties` is either `NULL` or a pointer to an array of `VkDisplayModeProperties2KHR` structures.

`vkGetDisplayModeProperties2KHR` behaves similarly to vkGetDisplayModePropertiesKHR, with the ability to return extended information via chained output structures.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `display` must be a valid VkDisplayKHR handle

- `pPropertyCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pPropertyCount` is not `0`, and `pProperties` is not `NULL`, `pProperties` must be a valid pointer to an array of `pPropertyCount` VkDisplayModeProperties2KHR structures

- `display` must have been created, allocated, or retrieved from `physicalDevice`

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkDisplayModeProperties2KHR` structure is defined as:

    typedef struct VkDisplayModeProperties2KHR {
        VkStructureType               sType;
        void*                         pNext;
        VkDisplayModePropertiesKHR    displayModeProperties;
    } VkDisplayModeProperties2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `displayModeProperties` is a VkDisplayModePropertiesKHR structure.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DISPLAY_MODE_PROPERTIES_2_KHR`

- `pNext` must be `NULL`

The `VkDisplayModeParametersKHR` structure is defined as:

    typedef struct VkDisplayModeParametersKHR {
        VkExtent2D    visibleRegion;
        uint32_t      refreshRate;
    } VkDisplayModeParametersKHR;

- `visibleRegion` is the 2D extents of the visible region.

- `refreshRate` is a `uint32_t` that is the number of times the display is refreshed each second multiplied by 1000.

| Note For example, a 60Hz display mode would report a `refreshRate` of 60,000.

Valid Usage

- The `width` member of `visibleRegion` must be greater than `0`

- The `height` member of `visibleRegion` must be greater than `0`

- `refreshRate` must be greater than `0`

Additional modes may also be created by calling:

    VkResult vkCreateDisplayModeKHR(
        VkPhysicalDevice                            physicalDevice,
        VkDisplayKHR                                display,
        const VkDisplayModeCreateInfoKHR*           pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkDisplayModeKHR*                           pMode);

- `physicalDevice` is the physical device associated with `display`.

- `display` is the display to create an additional mode for.

- `pCreateInfo` is a VkDisplayModeCreateInfoKHR structure describing the new mode to create.

- `pAllocator` is the allocator used for host memory allocated for the display mode object when there is no more specific allocator available (see Memory Allocation).

- `pMode` returns the handle of the mode created.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `display` must be a valid VkDisplayKHR handle

- `pCreateInfo` must be a valid pointer to a valid VkDisplayModeCreateInfoKHR structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pMode` must be a valid pointer to a VkDisplayModeKHR handle

- `display` must have been created, allocated, or retrieved from `physicalDevice`

Host Synchronization

- Host access to `display` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_INITIALIZATION_FAILED`

The `VkDisplayModeCreateInfoKHR` structure is defined as:

    typedef struct VkDisplayModeCreateInfoKHR {
        VkStructureType                sType;
        const void*                    pNext;
        VkDisplayModeCreateFlagsKHR    flags;
        VkDisplayModeParametersKHR     parameters;
    } VkDisplayModeCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use, and must be zero.

- `parameters` is a VkDisplayModeParametersKHR structure describing the display parameters to use in creating the new mode. If the parameters are not compatible with the specified display, the implementation must return `VK_ERROR_INITIALIZATION_FAILED`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DISPLAY_MODE_CREATE_INFO_KHR`

- `pNext` must be `NULL`

- `flags` must be `0`

- `parameters` must be a valid VkDisplayModeParametersKHR structure

Applications that wish to present directly to a display must select which layer, or “plane” of the display they wish to target, and a mode to use with the display. Each display supports at least one plane. The capabilities of a given mode and plane combination are determined by calling:

    VkResult vkGetDisplayPlaneCapabilitiesKHR(
        VkPhysicalDevice                            physicalDevice,
        VkDisplayModeKHR                            mode,
        uint32_t                                    planeIndex,
        VkDisplayPlaneCapabilitiesKHR*              pCapabilities);

- `physicalDevice` is the physical device associated with `display`

- `mode` is the display mode the application intends to program when using the specified plane. Note this parameter also implicitly specifies a display.

- `planeIndex` is the plane which the application intends to use with the display, and is less than the number of display planes supported by the device.

- `pCapabilities` is a pointer to a VkDisplayPlaneCapabilitiesKHR structure in which the capabilities are returned.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `mode` must be a valid VkDisplayModeKHR handle

- `pCapabilities` must be a valid pointer to a VkDisplayPlaneCapabilitiesKHR structure

Host Synchronization

- Host access to `mode` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkDisplayPlaneCapabilitiesKHR` structure is defined as:

    typedef struct VkDisplayPlaneCapabilitiesKHR {
        VkDisplayPlaneAlphaFlagsKHR    supportedAlpha;
        VkOffset2D                     minSrcPosition;
        VkOffset2D                     maxSrcPosition;
        VkExtent2D                     minSrcExtent;
        VkExtent2D                     maxSrcExtent;
        VkOffset2D                     minDstPosition;
        VkOffset2D                     maxDstPosition;
        VkExtent2D                     minDstExtent;
        VkExtent2D                     maxDstExtent;
    } VkDisplayPlaneCapabilitiesKHR;

- `supportedAlpha` is a bitmask of VkDisplayPlaneAlphaFlagBitsKHR describing the supported alpha blending modes.

- `minSrcPosition` is the minimum source rectangle offset supported by this plane using the specified mode.

- `maxSrcPosition` is the maximum source rectangle offset supported by this plane using the specified mode. The `x` and `y` components of `maxSrcPosition` must each be greater than or equal to the `x` and `y` components of `minSrcPosition`, respectively.

- `minSrcExtent` is the minimum source rectangle size supported by this plane using the specified mode.

- `maxSrcExtent` is the maximum source rectangle size supported by this plane using the specified mode.

- `minDstPosition`, `maxDstPosition`, `minDstExtent`, `maxDstExtent` all have similar semantics to their corresponding `*Src*` equivalents, but apply to the output region within the mode rather than the input region within the source image. Unlike the `*Src*` offsets, `minDstPosition` and `maxDstPosition` may contain negative values.

The minimum and maximum position and extent fields describe the implementation limits, if any, as they apply to the specified display mode and plane. Vendors may support displaying a subset of a swapchain’s presentable images on the specified display plane. This is expressed by returning `minSrcPosition`, `maxSrcPosition`, `minSrcExtent`, and `maxSrcExtent` values that indicate a range of possible positions and sizes may be used to specify the region within the presentable images that source pixels will be read from when creating a swapchain on the specified display mode and plane.

Vendors may also support mapping the presentable images’ content to a subset or superset of the visible region in the specified display mode. This is expressed by returning `minDstPosition`, `maxDstPosition`, `minDstExtent` and `maxDstExtent` values that indicate a range of possible positions and sizes may be used to describe the region within the display mode that the source pixels will be mapped to.

Other vendors may support only a 1-1 mapping between pixels in the presentable images and the display mode. This may be indicated by returning (0,0) for `minSrcPosition`, `maxSrcPosition`, `minDstPosition`, and `maxDstPosition`, and (display mode width, display mode height) for `minSrcExtent`, `maxSrcExtent`, `minDstExtent`, and `maxDstExtent`.

These values indicate the limits of the implementation’s individual fields. Not all combinations of values within the offset and extent ranges returned in `VkDisplayPlaneCapabilitiesKHR` are guaranteed to be supported. Presentation requests specifying unsupported combinations may fail.

To query the capabilities of a given mode and plane combination, call:

    VkResult vkGetDisplayPlaneCapabilities2KHR(
        VkPhysicalDevice                            physicalDevice,
        const VkDisplayPlaneInfo2KHR*               pDisplayPlaneInfo,
        VkDisplayPlaneCapabilities2KHR*             pCapabilities);

- `physicalDevice` is the physical device associated with `pDisplayPlaneInfo`.

- `pDisplayPlaneInfo` is a pointer to a VkDisplayPlaneInfo2KHR structure describing the plane and mode.

- `pCapabilities` is a pointer to a VkDisplayPlaneCapabilities2KHR structure in which the capabilities are returned.

`vkGetDisplayPlaneCapabilities2KHR` behaves similarly to vkGetDisplayPlaneCapabilitiesKHR, with the ability to specify extended inputs via chained input structures, and to return extended information via chained output structures.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pDisplayPlaneInfo` must be a valid pointer to a valid VkDisplayPlaneInfo2KHR structure

- `pCapabilities` must be a valid pointer to a VkDisplayPlaneCapabilities2KHR structure

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkDisplayPlaneInfo2KHR` structure is defined as:

    typedef struct VkDisplayPlaneInfo2KHR {
        VkStructureType     sType;
        const void*         pNext;
        VkDisplayModeKHR    mode;
        uint32_t            planeIndex;
    } VkDisplayPlaneInfo2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `mode` is the display mode the application intends to program when using the specified plane.

| Note This parameter also implicitly specifies a display.

- `planeIndex` is the plane which the application intends to use with the display.

The members of `VkDisplayPlaneInfo2KHR` correspond to the arguments to vkGetDisplayPlaneCapabilitiesKHR, with `sType` and `pNext` added for extensibility.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DISPLAY_PLANE_INFO_2_KHR`

- `pNext` must be `NULL`

- `mode` must be a valid VkDisplayModeKHR handle

Host Synchronization

- Host access to `mode` must be externally synchronized

The `VkDisplayPlaneCapabilities2KHR` structure is defined as:

    typedef struct VkDisplayPlaneCapabilities2KHR {
        VkStructureType                  sType;
        void*                            pNext;
        VkDisplayPlaneCapabilitiesKHR    capabilities;
    } VkDisplayPlaneCapabilities2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `capabilities` is a VkDisplayPlaneCapabilitiesKHR structure.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DISPLAY_PLANE_CAPABILITIES_2_KHR`

- `pNext` must be `NULL`

#### 32.3.2. Display Control

To set the power state of a display, call:

    VkResult vkDisplayPowerControlEXT(
        VkDevice                                    device,
        VkDisplayKHR                                display,
        const VkDisplayPowerInfoEXT*                pDisplayPowerInfo);

- `device` is a logical device associated with `display`.

- `display` is the display whose power state is modified.

- `pDisplayPowerInfo` is a VkDisplayPowerInfoEXT structure specifying the new power state of `display`.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `display` must be a valid VkDisplayKHR handle

- `pDisplayPowerInfo` must be a valid pointer to a valid VkDisplayPowerInfoEXT structure

- Both of `device`, and `display` must have been created, allocated, or retrieved from the same VkPhysicalDevice

Return Codes

Success

  - `VK_SUCCESS`

The `VkDisplayPowerInfoEXT` structure is defined as:

    typedef struct VkDisplayPowerInfoEXT {
        VkStructureType           sType;
        const void*               pNext;
        VkDisplayPowerStateEXT    powerState;
    } VkDisplayPowerInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `powerState` is a VkDisplayPowerStateEXT value specifying the new power state of the display.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DISPLAY_POWER_INFO_EXT`

- `pNext` must be `NULL`

- `powerState` must be a valid VkDisplayPowerStateEXT value

Possible values of VkDisplayPowerInfoEXT::`powerState`, specifying the new power state of a display, are:

    typedef enum VkDisplayPowerStateEXT {
        VK_DISPLAY_POWER_STATE_OFF_EXT = 0,
        VK_DISPLAY_POWER_STATE_SUSPEND_EXT = 1,
        VK_DISPLAY_POWER_STATE_ON_EXT = 2,
        VK_DISPLAY_POWER_STATE_MAX_ENUM_EXT = 0x7FFFFFFF
    } VkDisplayPowerStateEXT;

- `VK_DISPLAY_POWER_STATE_OFF_EXT` specifies that the display is powered down.

- `VK_DISPLAY_POWER_STATE_SUSPEND_EXT` specifies that the display is put into a low power mode, from which it may be able to transition back to `VK_DISPLAY_POWER_STATE_ON_EXT` more quickly than if it were in `VK_DISPLAY_POWER_STATE_OFF_EXT`. This state may be the same as `VK_DISPLAY_POWER_STATE_OFF_EXT`.

- `VK_DISPLAY_POWER_STATE_ON_EXT` specifies that the display is powered on.

#### 32.3.3. Display Surfaces

A complete display configuration includes a mode, one or more display planes and any parameters describing their behavior, and parameters describing some aspects of the images associated with those planes. Display surfaces describe the configuration of a single plane within a complete display configuration. To create a `VkSurfaceKHR` structure for a display surface, call:

    VkResult vkCreateDisplayPlaneSurfaceKHR(
        VkInstance                                  instance,
        const VkDisplaySurfaceCreateInfoKHR*        pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkSurfaceKHR*                               pSurface);

- `instance` is the instance corresponding to the physical device the targeted display is on.

- `pCreateInfo` is a pointer to a VkDisplaySurfaceCreateInfoKHR structure specifying which mode, plane, and other parameters to use, as described below.

- `pAllocator` is the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation).

- `pSurface` is a pointer to a VkSurfaceKHR handle in which the created surface is returned.

Valid Usage (Implicit)

- `instance` must be a valid VkInstance handle

- `pCreateInfo` must be a valid pointer to a valid VkDisplaySurfaceCreateInfoKHR structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pSurface` must be a valid pointer to a VkSurfaceKHR handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkDisplaySurfaceCreateInfoKHR` structure is defined as:

    typedef struct VkDisplaySurfaceCreateInfoKHR {
        VkStructureType                   sType;
        const void*                       pNext;
        VkDisplaySurfaceCreateFlagsKHR    flags;
        VkDisplayModeKHR                  displayMode;
        uint32_t                          planeIndex;
        uint32_t                          planeStackIndex;
        VkSurfaceTransformFlagBitsKHR     transform;
        float                             globalAlpha;
        VkDisplayPlaneAlphaFlagBitsKHR    alphaMode;
        VkExtent2D                        imageExtent;
    } VkDisplaySurfaceCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use, and must be zero.

- `displayMode` is a VkDisplayModeKHR handle specifying the mode to use when displaying this surface.

- `planeIndex` is the plane on which this surface appears.

- `planeStackIndex` is the z-order of the plane.

- `transform` is a VkSurfaceTransformFlagBitsKHR value specifying the transformation to apply to images as part of the scanout operation.

- `globalAlpha` is the global alpha value. This value is ignored if `alphaMode` is not `VK_DISPLAY_PLANE_ALPHA_GLOBAL_BIT_KHR`.

- `alphaMode` is a VkDisplayPlaneAlphaFlagBitsKHR value specifying the type of alpha blending to use.

- `imageExtent` The size of the presentable images to use with the surface.

| Note Creating a display surface must not modify the state of the displays, planes, or other resources it names. For example, it must not apply the specified mode to be set on the associated display. Application of display configuration occurs as a side effect of presenting to a display surface.

Valid Usage

- `planeIndex` must be less than the number of display planes supported by the device as determined by calling `vkGetPhysicalDeviceDisplayPlanePropertiesKHR`

- If the `planeReorderPossible` member of the `VkDisplayPropertiesKHR` structure returned by `vkGetPhysicalDeviceDisplayPropertiesKHR` for the display corresponding to `displayMode` is `VK_TRUE` then `planeStackIndex` must be less than the number of display planes supported by the device as determined by calling `vkGetPhysicalDeviceDisplayPlanePropertiesKHR`; otherwise `planeStackIndex` must equal the `currentStackIndex` member of `VkDisplayPlanePropertiesKHR` returned by `vkGetPhysicalDeviceDisplayPlanePropertiesKHR` for the display plane corresponding to `displayMode`

- If `alphaMode` is `VK_DISPLAY_PLANE_ALPHA_GLOBAL_BIT_KHR` then `globalAlpha` must be between `0` and `1`, inclusive

- `alphaMode` must be `0` or one of the bits present in the `supportedAlpha` member of `VkDisplayPlaneCapabilitiesKHR` returned by `vkGetDisplayPlaneCapabilitiesKHR` for the display plane corresponding to `displayMode`

- The `width` and `height` members of `imageExtent` must be less than the `maxImageDimensions2D` member of `VkPhysicalDeviceLimits`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DISPLAY_SURFACE_CREATE_INFO_KHR`

- `pNext` must be `NULL`

- `flags` must be `0`

- `displayMode` must be a valid VkDisplayModeKHR handle

- `transform` must be a valid VkSurfaceTransformFlagBitsKHR value

- `alphaMode` must be a valid VkDisplayPlaneAlphaFlagBitsKHR value

    typedef VkFlags VkDisplaySurfaceCreateFlagsKHR;

`VkDisplaySurfaceCreateFlagsKHR` is a bitmask type for setting a mask, but is currently reserved for future use.

Possible values of VkDisplaySurfaceCreateInfoKHR::`alphaMode`, specifying the type of alpha blending to use on a display, are:

    typedef enum VkDisplayPlaneAlphaFlagBitsKHR {
        VK_DISPLAY_PLANE_ALPHA_OPAQUE_BIT_KHR = 0x00000001,
        VK_DISPLAY_PLANE_ALPHA_GLOBAL_BIT_KHR = 0x00000002,
        VK_DISPLAY_PLANE_ALPHA_PER_PIXEL_BIT_KHR = 0x00000004,
        VK_DISPLAY_PLANE_ALPHA_PER_PIXEL_PREMULTIPLIED_BIT_KHR = 0x00000008,
        VK_DISPLAY_PLANE_ALPHA_FLAG_BITS_MAX_ENUM_KHR = 0x7FFFFFFF
    } VkDisplayPlaneAlphaFlagBitsKHR;

- `VK_DISPLAY_PLANE_ALPHA_OPAQUE_BIT_KHR` specifies that the source image will be treated as opaque.

- `VK_DISPLAY_PLANE_ALPHA_GLOBAL_BIT_KHR` specifies that a global alpha value must be specified that will be applied to all pixels in the source image.

- `VK_DISPLAY_PLANE_ALPHA_PER_PIXEL_BIT_KHR` specifies that the alpha value will be determined by the alpha channel of the source image’s pixels. If the source format contains no alpha values, no blending will be applied. The source alpha values are not premultiplied into the source image’s other color channels.

- `VK_DISPLAY_PLANE_ALPHA_PER_PIXEL_PREMULTIPLIED_BIT_KHR` is equivalent to `VK_DISPLAY_PLANE_ALPHA_PER_PIXEL_BIT_KHR`, except the source alpha values are assumed to be premultiplied into the source image’s other color channels.

    typedef VkFlags VkDisplayPlaneAlphaFlagsKHR;

`VkDisplayPlaneAlphaFlagsKHR` is a bitmask type for setting a mask of zero or more VkDisplayPlaneAlphaFlagBitsKHR.

#### 32.3.4. Presenting to headless surfaces

Vulkan rendering can be presented to a headless surface, where the presentation operation is a no-op producing no externally-visible result.

| Note Because there is no real presentation target, the headless presentation engine may be extended to impose an arbitrary or customisable set of restrictions and features. This makes it a useful portable test target for applications targeting a wide range of presentation engines where the actual target presentation engines might be scarce, unavailable or otherwise undesirable or inconvenient to use for general Vulkan application development. The usual surface query mechanisms must be used to determine the actual restrictions and features of the implementation.

To create a headless `VkSurfaceKHR` object, call:

    VkResult vkCreateHeadlessSurfaceEXT(
        VkInstance                                  instance,
        const VkHeadlessSurfaceCreateInfoEXT*       pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkSurfaceKHR*                               pSurface);

- `instance` is the instance to associate the surface with.

- `pCreateInfo` is a pointer to a VkHeadlessSurfaceCreateInfoEXT structure containing parameters affecting the creation of the surface object.

- `pAllocator` is the allocator used for host memory allocated for the surface object when there is no more specific allocator available (see Memory Allocation).

- `pSurface` is a pointer to a `VkSurfaceKHR` handle in which the created surface object is returned.

Valid Usage (Implicit)

- `instance` must be a valid VkInstance handle

- `pCreateInfo` must be a valid pointer to a valid VkHeadlessSurfaceCreateInfoEXT structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pSurface` must be a valid pointer to a VkSurfaceKHR handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkHeadlessSurfaceCreateInfoEXT` structure is defined as:

    typedef struct VkHeadlessSurfaceCreateInfoEXT {
        VkStructureType                    sType;
        const void*                        pNext;
        VkHeadlessSurfaceCreateFlagsEXT    flags;
    } VkHeadlessSurfaceCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is reserved for future use.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_HEADLESS_SURFACE_CREATE_INFO_EXT`

- `pNext` must be `NULL`

- `flags` must be `0`

For headless surfaces, `currentExtent` is undefined (0xFFFFFFFF, 0xFFFFFFFF). Whatever the application sets a swapchain’s `imageExtent` to will be the size of the surface, after the first image is presented.

### 32.4. Querying for WSI Support

Not all physical devices will include WSI support. Within a physical device, not all queue families will support presentation. WSI support and compatibility can be determined in a platform-neutral manner (which determines support for presentation to a particular surface object) and additionally may be determined in platform-specific manners (which determine support for presentation on the specified physical device but do not guarantee support for presentation to a particular surface object).

To determine whether a queue family of a physical device supports presentation to a given surface, call:

    VkResult vkGetPhysicalDeviceSurfaceSupportKHR(
        VkPhysicalDevice                            physicalDevice,
        uint32_t                                    queueFamilyIndex,
        VkSurfaceKHR                                surface,
        VkBool32*                                   pSupported);

- `physicalDevice` is the physical device.

- `queueFamilyIndex` is the queue family.

- `surface` is the surface.

- `pSupported` is a pointer to a `VkBool32`, which is set to `VK_TRUE` to indicate support, and `VK_FALSE` otherwise.

Valid Usage

- `queueFamilyIndex` must be less than `pQueueFamilyPropertyCount` returned by `vkGetPhysicalDeviceQueueFamilyProperties` for the given `physicalDevice`

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `surface` must be a valid VkSurfaceKHR handle

- `pSupported` must be a valid pointer to a `VkBool32` value

- Both of `physicalDevice`, and `surface` must have been created, allocated, or retrieved from the same VkInstance

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_SURFACE_LOST_KHR`

#### 32.4.1. Android Platform

On Android, all physical devices and queue families must be capable of presentation with any native window. As a result there is no Android-specific query for these capabilities.

#### 32.4.2. Wayland Platform

To determine whether a queue family of a physical device supports presentation to a Wayland compositor, call:

    VkBool32 vkGetPhysicalDeviceWaylandPresentationSupportKHR(
        VkPhysicalDevice                            physicalDevice,
        uint32_t                                    queueFamilyIndex,
        struct wl_display*                          display);

- `physicalDevice` is the physical device.

- `queueFamilyIndex` is the queue family index.

- `display` is a pointer to the `wl_display` associated with a Wayland compositor.

This platform-specific function can be called prior to creating a surface.

Valid Usage

- `queueFamilyIndex` must be less than `pQueueFamilyPropertyCount` returned by `vkGetPhysicalDeviceQueueFamilyProperties` for the given `physicalDevice`

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `display` must be a valid pointer to a `wl_display` value

#### 32.4.3. Win32 Platform

To determine whether a queue family of a physical device supports presentation to the Microsoft Windows desktop, call:

    VkBool32 vkGetPhysicalDeviceWin32PresentationSupportKHR(
        VkPhysicalDevice                            physicalDevice,
        uint32_t                                    queueFamilyIndex);

- `physicalDevice` is the physical device.

- `queueFamilyIndex` is the queue family index.

This platform-specific function can be called prior to creating a surface.

Valid Usage

- `queueFamilyIndex` must be less than `pQueueFamilyPropertyCount` returned by `vkGetPhysicalDeviceQueueFamilyProperties` for the given `physicalDevice`

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

#### 32.4.4. XCB Platform

To determine whether a queue family of a physical device supports presentation to an X11 server, using the XCB client-side library, call:

    VkBool32 vkGetPhysicalDeviceXcbPresentationSupportKHR(
        VkPhysicalDevice                            physicalDevice,
        uint32_t                                    queueFamilyIndex,
        xcb_connection_t*                           connection,
        xcb_visualid_t                              visual_id);

- `physicalDevice` is the physical device.

- `queueFamilyIndex` is the queue family index.

- `connection` is a pointer to an `xcb_connection_t` to the X server.

- `visual_id` is an X11 visual (`xcb_visualid_t`).

This platform-specific function can be called prior to creating a surface.

Valid Usage

- `queueFamilyIndex` must be less than `pQueueFamilyPropertyCount` returned by `vkGetPhysicalDeviceQueueFamilyProperties` for the given `physicalDevice`

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `connection` must be a valid pointer to an `xcb_connection_t` value

#### 32.4.5. Xlib Platform

To determine whether a queue family of a physical device supports presentation to an X11 server, using the Xlib client-side library, call:

    VkBool32 vkGetPhysicalDeviceXlibPresentationSupportKHR(
        VkPhysicalDevice                            physicalDevice,
        uint32_t                                    queueFamilyIndex,
        Display*                                    dpy,
        VisualID                                    visualID);

- `physicalDevice` is the physical device.

- `queueFamilyIndex` is the queue family index.

- `dpy` is a pointer to an Xlib `Display` connection to the server.

- `visualId` is an X11 visual (`VisualID`).

This platform-specific function can be called prior to creating a surface.

Valid Usage

- `queueFamilyIndex` must be less than `pQueueFamilyPropertyCount` returned by `vkGetPhysicalDeviceQueueFamilyProperties` for the given `physicalDevice`

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `dpy` must be a valid pointer to a `Display` value

#### 32.4.6. Fuchsia Platform

On Fuchsia, all physical devices and queue families must be capable of presentation with any ImagePipe. As a result there is no Fuchsia-specific query for these capabilities.

#### 32.4.7. Google Games Platform

On Google Games Platform, all physical devices and queue families with the `VK_QUEUE_GRAPHICS_BIT` or `VK_QUEUE_COMPUTE_BIT` capabilities must be capable of presentation with any Google Games Platform stream descriptor. As a result, there is no query specific to Google Games Platform for these capabilities.

#### 32.4.8. iOS Platform

On iOS, all physical devices and queue families must be capable of presentation with any layer. As a result there is no iOS-specific query for these capabilities.

#### 32.4.9. macOS Platform

On macOS, all physical devices and queue families must be capable of presentation with any layer. As a result there is no macOS-specific query for these capabilities.

#### 32.4.10. VI Platform

On VI, all physical devices and queue families must be capable of presentation with any layer. As a result there is no VI-specific query for these capabilities.

### 32.5. Surface Queries

The capabilities of a swapchain targeting a surface are the intersection of the capabilities of the WSI platform, the native window or display, and the physical device. The resulting capabilities can be obtained with the queries listed below in this section.

| Note In addition to the surface capabilities as obtained by surface queries below, swapchain images are also subject to ordinary image creation limits as reported by vkGetPhysicalDeviceImageFormatProperties. As an application is instructed by the appropriate Valid Usage sections, both the surface capabilities and the image creation limits have to be satisfied whenever swapchain images are created.

#### 32.5.1. Surface Capabilities

To query the basic capabilities of a surface, needed in order to create a swapchain, call:

    VkResult vkGetPhysicalDeviceSurfaceCapabilitiesKHR(
        VkPhysicalDevice                            physicalDevice,
        VkSurfaceKHR                                surface,
        VkSurfaceCapabilitiesKHR*                   pSurfaceCapabilities);

- `physicalDevice` is the physical device that will be associated with the swapchain to be created, as described for vkCreateSwapchainKHR.

- `surface` is the surface that will be associated with the swapchain.

- `pSurfaceCapabilities` is a pointer to a VkSurfaceCapabilitiesKHR structure in which the capabilities are returned.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `surface` must be a valid VkSurfaceKHR handle

- `pSurfaceCapabilities` must be a valid pointer to a VkSurfaceCapabilitiesKHR structure

- Both of `physicalDevice`, and `surface` must have been created, allocated, or retrieved from the same VkInstance

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_SURFACE_LOST_KHR`

The `VkSurfaceCapabilitiesKHR` structure is defined as:

    typedef struct VkSurfaceCapabilitiesKHR {
        uint32_t                         minImageCount;
        uint32_t                         maxImageCount;
        VkExtent2D                       currentExtent;
        VkExtent2D                       minImageExtent;
        VkExtent2D                       maxImageExtent;
        uint32_t                         maxImageArrayLayers;
        VkSurfaceTransformFlagsKHR       supportedTransforms;
        VkSurfaceTransformFlagBitsKHR    currentTransform;
        VkCompositeAlphaFlagsKHR         supportedCompositeAlpha;
        VkImageUsageFlags                supportedUsageFlags;
    } VkSurfaceCapabilitiesKHR;

- `minImageCount` is the minimum number of images the specified device supports for a swapchain created for the surface, and will be at least one.

- `maxImageCount` is the maximum number of images the specified device supports for a swapchain created for the surface, and will be either 0, or greater than or equal to `minImageCount`. A value of 0 means that there is no limit on the number of images, though there may be limits related to the total amount of memory used by presentable images.

- `currentExtent` is the current width and height of the surface, or the special value (0xFFFFFFFF, 0xFFFFFFFF) indicating that the surface size will be determined by the extent of a swapchain targeting the surface.

- `minImageExtent` contains the smallest valid swapchain extent for the surface on the specified device. The `width` and `height` of the extent will each be less than or equal to the corresponding `width` and `height` of `currentExtent`, unless `currentExtent` has the special value described above.

- `maxImageExtent` contains the largest valid swapchain extent for the surface on the specified device. The `width` and `height` of the extent will each be greater than or equal to the corresponding `width` and `height` of `minImageExtent`. The `width` and `height` of the extent will each be greater than or equal to the corresponding `width` and `height` of `currentExtent`, unless `currentExtent` has the special value described above.

- `maxImageArrayLayers` is the maximum number of layers presentable images can have for a swapchain created for this device and surface, and will be at least one.

- `supportedTransforms` is a bitmask of VkSurfaceTransformFlagBitsKHR indicating the presentation transforms supported for the surface on the specified device. At least one bit will be set.

- `currentTransform` is VkSurfaceTransformFlagBitsKHR value indicating the surface’s current transform relative to the presentation engine’s natural orientation.

- `supportedCompositeAlpha` is a bitmask of VkCompositeAlphaFlagBitsKHR, representing the alpha compositing modes supported by the presentation engine for the surface on the specified device, and at least one bit will be set. Opaque composition can be achieved in any alpha compositing mode by either using an image format that has no alpha component, or by ensuring that all pixels in the presentable images have an alpha value of 1.0.

- `supportedUsageFlags` is a bitmask of VkImageUsageFlagBits representing the ways the application can use the presentable images of a swapchain created with VkPresentModeKHR set to `VK_PRESENT_MODE_IMMEDIATE_KHR`, `VK_PRESENT_MODE_MAILBOX_KHR`, `VK_PRESENT_MODE_FIFO_KHR` or `VK_PRESENT_MODE_FIFO_RELAXED_KHR` for the surface on the specified device. `VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT` must be included in the set but implementations may support additional usages.

| Note Supported usage flags of a presentable image when using `VK_PRESENT_MODE_SHARED_DEMAND_REFRESH_KHR` or `VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR` presentation mode are provided by VkSharedPresentSurfaceCapabilitiesKHR::`sharedPresentSupportedUsageFlags`.

| Note Formulas such as min(N, `maxImageCount`) are not correct, since `maxImageCount` may be zero.

To query the basic capabilities of a surface defined by the core or extensions, call:

    VkResult vkGetPhysicalDeviceSurfaceCapabilities2KHR(
        VkPhysicalDevice                            physicalDevice,
        const VkPhysicalDeviceSurfaceInfo2KHR*      pSurfaceInfo,
        VkSurfaceCapabilities2KHR*                  pSurfaceCapabilities);

- `physicalDevice` is the physical device that will be associated with the swapchain to be created, as described for vkCreateSwapchainKHR.

- `pSurfaceInfo` is a pointer to a VkPhysicalDeviceSurfaceInfo2KHR structure describing the surface and other fixed parameters that would be consumed by vkCreateSwapchainKHR.

- `pSurfaceCapabilities` is a pointer to a VkSurfaceCapabilities2KHR structure in which the capabilities are returned.

`vkGetPhysicalDeviceSurfaceCapabilities2KHR` behaves similarly to vkGetPhysicalDeviceSurfaceCapabilitiesKHR, with the ability to specify extended inputs via chained input structures, and to return extended information via chained output structures.

Valid Usage

- If a VkSurfaceCapabilitiesFullScreenExclusiveEXT structure is included in the `pNext` chain of `pSurfaceCapabilities`, a VkSurfaceFullScreenExclusiveWin32InfoEXT structure must be included in the `pNext` chain of `pSurfaceInfo`.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pSurfaceInfo` must be a valid pointer to a valid VkPhysicalDeviceSurfaceInfo2KHR structure

- `pSurfaceCapabilities` must be a valid pointer to a VkSurfaceCapabilities2KHR structure

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_SURFACE_LOST_KHR`

The `VkPhysicalDeviceSurfaceInfo2KHR` structure is defined as:

    typedef struct VkPhysicalDeviceSurfaceInfo2KHR {
        VkStructureType    sType;
        const void*        pNext;
        VkSurfaceKHR       surface;
    } VkPhysicalDeviceSurfaceInfo2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `surface` is the surface that will be associated with the swapchain.

The members of `VkPhysicalDeviceSurfaceInfo2KHR` correspond to the arguments to vkGetPhysicalDeviceSurfaceCapabilitiesKHR, with `sType` and `pNext` added for extensibility.

Additional capabilities of a surface may be available to swapchains created with different full-screen exclusive settings - particularly if exclusive full-screen access is application controlled. These additional capabilities can be queried by adding a VkSurfaceFullScreenExclusiveInfoEXT structure to the `pNext` chain of this structure when used to query surface properties. Additionally, for Win32 surfaces with application controlled exclusive full-screen access, chaining a VkSurfaceFullScreenExclusiveWin32InfoEXT structure may also report additional surface capabilities. These additional capabilities only apply to swapchains created with the same parameters included in the `pNext` chain of VkSwapchainCreateInfoKHR.

Valid Usage

- If the `pNext` chain includes a VkSurfaceFullScreenExclusiveInfoEXT structure with its `fullScreenExclusive` member set to `VK_FULL_SCREEN_EXCLUSIVE_APPLICATION_CONTROLLED_EXT`, and `surface` was created using vkCreateWin32SurfaceKHR, a VkSurfaceFullScreenExclusiveWin32InfoEXT structure must be included in the `pNext` chain

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SURFACE_INFO_2_KHR`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkSurfaceFullScreenExclusiveInfoEXT or VkSurfaceFullScreenExclusiveWin32InfoEXT

- The `sType` value of each struct in the `pNext` chain must be unique

- `surface` must be a valid VkSurfaceKHR handle

If the `pNext` chain of VkSwapchainCreateInfoKHR includes a `VkSurfaceFullScreenExclusiveInfoEXT` structure, then that structure specifies the application’s preferred full-screen transition behavior.

The `VkSurfaceFullScreenExclusiveInfoEXT` structure is defined as:

    typedef struct VkSurfaceFullScreenExclusiveInfoEXT {
        VkStructureType             sType;
        void*                       pNext;
        VkFullScreenExclusiveEXT    fullScreenExclusive;
    } VkSurfaceFullScreenExclusiveInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `fullScreenExclusive` is a VkFullScreenExclusiveEXT value specifying the preferred full-screen transition behavior.

If this structure is not present, `fullScreenExclusive` is considered to be `VK_FULL_SCREEN_EXCLUSIVE_DEFAULT_EXT`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SURFACE_FULL_SCREEN_EXCLUSIVE_INFO_EXT`

- `fullScreenExclusive` must be a valid VkFullScreenExclusiveEXT value

Possible values of `VkSurfaceFullScreenExclusiveInfoEXT`::`fullScreenExclusive` are:

    typedef enum VkFullScreenExclusiveEXT {
        VK_FULL_SCREEN_EXCLUSIVE_DEFAULT_EXT = 0,
        VK_FULL_SCREEN_EXCLUSIVE_ALLOWED_EXT = 1,
        VK_FULL_SCREEN_EXCLUSIVE_DISALLOWED_EXT = 2,
        VK_FULL_SCREEN_EXCLUSIVE_APPLICATION_CONTROLLED_EXT = 3,
        VK_FULL_SCREEN_EXCLUSIVE_MAX_ENUM_EXT = 0x7FFFFFFF
    } VkFullScreenExclusiveEXT;

- `VK_FULL_SCREEN_EXCLUSIVE_DEFAULT_EXT` indicates the implementation should determine the appropriate full-screen method by whatever means it deems appropriate.

- `VK_FULL_SCREEN_EXCLUSIVE_ALLOWED_EXT` indicates the implementation may use full-screen exclusive mechanisms when available. Such mechanisms may result in better performance and/or the availability of different presentation capabilities, but may require a more disruptive transition during swapchain initialization, first presentation and/or destruction.

- `VK_FULL_SCREEN_EXCLUSIVE_DISALLOWED_EXT` indicates the implementation should avoid using full-screen mechanisms which rely on disruptive transitions.

- `VK_FULL_SCREEN_EXCLUSIVE_APPLICATION_CONTROLLED_EXT` indicates the application will manage full-screen exclusive mode by using the vkAcquireFullScreenExclusiveModeEXT and vkReleaseFullScreenExclusiveModeEXT commands.

The `VkSurfaceFullScreenExclusiveWin32InfoEXT` structure is defined as:

    typedef struct VkSurfaceFullScreenExclusiveWin32InfoEXT {
        VkStructureType    sType;
        const void*        pNext;
        HMONITOR           hmonitor;
    } VkSurfaceFullScreenExclusiveWin32InfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `hmonitor` is the Win32 `HMONITOR` handle identifying the display to create the surface with.

| Note If `hmonitor` is invalidated (e.g. the monitor is unplugged) during the lifetime of a swapchain created with this structure, operations on that swapchain will return `VK_ERROR_OUT_OF_DATE_KHR`.

| Note It’s the responsibility of the application to change the display settings of the targeted Win32 display using the appropriate platform APIs. Such changes may alter the surface capabilities reported for the created surface.

Valid Usage

- `hmonitor` must be a valid `HMONITOR`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SURFACE_FULL_SCREEN_EXCLUSIVE_WIN32_INFO_EXT`

The `VkSurfaceCapabilities2KHR` structure is defined as:

    typedef struct VkSurfaceCapabilities2KHR {
        VkStructureType             sType;
        void*                       pNext;
        VkSurfaceCapabilitiesKHR    surfaceCapabilities;
    } VkSurfaceCapabilities2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `surfaceCapabilities` is a VkSurfaceCapabilitiesKHR structure describing the capabilities of the specified surface.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SURFACE_CAPABILITIES_2_KHR`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkDisplayNativeHdrSurfaceCapabilitiesAMD, VkSharedPresentSurfaceCapabilitiesKHR, VkSurfaceCapabilitiesFullScreenExclusiveEXT, or VkSurfaceProtectedCapabilitiesKHR

- The `sType` value of each struct in the `pNext` chain must be unique

An application queries if a protected VkSurfaceKHR is displayable on a specific windowing system using `VkSurfaceProtectedCapabilitiesKHR`, which can be passed in `pNext` parameter of `VkSurfaceCapabilities2KHR`.

The `VkSurfaceProtectedCapabilitiesKHR` structure is defined as:

    typedef struct VkSurfaceProtectedCapabilitiesKHR {
        VkStructureType    sType;
        const void*        pNext;
        VkBool32           supportsProtected;
    } VkSurfaceProtectedCapabilitiesKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `supportsProtected` specifies whether a protected swapchain created from VkPhysicalDeviceSurfaceInfo2KHR::`surface` for a particular windowing system can be displayed on screen or not. If `supportsProtected` is `VK_TRUE`, then creation of swapchains with the `VK_SWAPCHAIN_CREATE_PROTECTED_BIT_KHR` flag set must be supported for `surface`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SURFACE_PROTECTED_CAPABILITIES_KHR`

The `VkSharedPresentSurfaceCapabilitiesKHR` structure is defined as:

    typedef struct VkSharedPresentSurfaceCapabilitiesKHR {
        VkStructureType      sType;
        void*                pNext;
        VkImageUsageFlags    sharedPresentSupportedUsageFlags;
    } VkSharedPresentSurfaceCapabilitiesKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `sharedPresentSupportedUsageFlags` is a bitmask of VkImageUsageFlagBits representing the ways the application can use the shared presentable image from a swapchain created with VkPresentModeKHR set to `VK_PRESENT_MODE_SHARED_DEMAND_REFRESH_KHR` or `VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR` for the surface on the specified device. `VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT` must be included in the set but implementations may support additional usages.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SHARED_PRESENT_SURFACE_CAPABILITIES_KHR`

The `VkDisplayNativeHdrSurfaceCapabilitiesAMD` structure is defined as:

    typedef struct VkDisplayNativeHdrSurfaceCapabilitiesAMD {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           localDimmingSupport;
    } VkDisplayNativeHdrSurfaceCapabilitiesAMD;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `localDimmingSupport` specifies whether the surface supports local dimming. If this is `VK_TRUE`, VkSwapchainDisplayNativeHdrCreateInfoAMD can be used to explicitly enable or disable local dimming for the surface. Local dimming may also be overriden by vkSetLocalDimmingAMD during the lifetime of the swapchain.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DISPLAY_NATIVE_HDR_SURFACE_CAPABILITIES_AMD`

The `VkSurfaceCapabilitiesFullScreenExclusiveEXT` structure is defined as:

    typedef struct VkSurfaceCapabilitiesFullScreenExclusiveEXT {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           fullScreenExclusiveSupported;
    } VkSurfaceCapabilitiesFullScreenExclusiveEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `fullScreenExclusiveControlSupported` is a boolean describing whether the surface is able to make use of exclusive full-screen access.

This structure can be included in the `pNext` chain of VkSurfaceCapabilities2KHR to determine support for exclusive full-screen access. If `fullScreenExclusiveSupported` is `VK_FALSE`, it indicates that exclusive full-screen access is not obtainable for this surface.

Applications must not attempt to create swapchains with `VK_FULL_SCREEN_EXCLUSIVE_APPLICATION_CONTROLLED_EXT` set if `fullScreenExclusiveSupported` is `VK_FALSE`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SURFACE_CAPABILITIES_FULL_SCREEN_EXCLUSIVE_EXT`

To query the basic capabilities of a surface, needed in order to create a swapchain, call:

    VkResult vkGetPhysicalDeviceSurfaceCapabilities2EXT(
        VkPhysicalDevice                            physicalDevice,
        VkSurfaceKHR                                surface,
        VkSurfaceCapabilities2EXT*                  pSurfaceCapabilities);

- `physicalDevice` is the physical device that will be associated with the swapchain to be created, as described for vkCreateSwapchainKHR.

- `surface` is the surface that will be associated with the swapchain.

- `pSurfaceCapabilities` is a pointer to a VkSurfaceCapabilities2EXT structure in which the capabilities are returned.

`vkGetPhysicalDeviceSurfaceCapabilities2EXT` behaves similarly to vkGetPhysicalDeviceSurfaceCapabilitiesKHR, with the ability to return extended information by adding extension structures to the `pNext` chain of its `pSurfaceCapabilities` parameter.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `surface` must be a valid VkSurfaceKHR handle

- `pSurfaceCapabilities` must be a valid pointer to a VkSurfaceCapabilities2EXT structure

- Both of `physicalDevice`, and `surface` must have been created, allocated, or retrieved from the same VkInstance

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_SURFACE_LOST_KHR`

The `VkSurfaceCapabilities2EXT` structure is defined as:

    typedef struct VkSurfaceCapabilities2EXT {
        VkStructureType                  sType;
        void*                            pNext;
        uint32_t                         minImageCount;
        uint32_t                         maxImageCount;
        VkExtent2D                       currentExtent;
        VkExtent2D                       minImageExtent;
        VkExtent2D                       maxImageExtent;
        uint32_t                         maxImageArrayLayers;
        VkSurfaceTransformFlagsKHR       supportedTransforms;
        VkSurfaceTransformFlagBitsKHR    currentTransform;
        VkCompositeAlphaFlagsKHR         supportedCompositeAlpha;
        VkImageUsageFlags                supportedUsageFlags;
        VkSurfaceCounterFlagsEXT         supportedSurfaceCounters;
    } VkSurfaceCapabilities2EXT;

All members of `VkSurfaceCapabilities2EXT` are identical to the corresponding members of VkSurfaceCapabilitiesKHR where one exists. The remaining members are:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `supportedSurfaceCounters` is a bitmask of VkSurfaceCounterFlagBitsEXT indicating the supported surface counter types.

Valid Usage

- `supportedSurfaceCounters` must not include `VK_SURFACE_COUNTER_VBLANK_EXT` unless the surface queried is a display surface.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SURFACE_CAPABILITIES_2_EXT`

- `pNext` must be `NULL`

Bits which can be set in VkSurfaceCapabilities2EXT::`supportedSurfaceCounters`, indicating supported surface counter types, are:

    typedef enum VkSurfaceCounterFlagBitsEXT {
        VK_SURFACE_COUNTER_VBLANK_EXT = 0x00000001,
        VK_SURFACE_COUNTER_FLAG_BITS_MAX_ENUM_EXT = 0x7FFFFFFF
    } VkSurfaceCounterFlagBitsEXT;

- `VK_SURFACE_COUNTER_VBLANK_EXT` specifies a counter incrementing once every time a vertical blanking period occurs on the display associated with the surface.

    typedef VkFlags VkSurfaceCounterFlagsEXT;

`VkSurfaceCounterFlagsEXT` is a bitmask type for setting a mask of zero or more VkSurfaceCounterFlagBitsEXT.

Bits which may be set in VkSurfaceCapabilitiesKHR::`supportedTransforms` indicating the presentation transforms supported for the surface on the specified device, and possible values of VkSurfaceCapabilitiesKHR::`currentTransform` is indicating the surface’s current transform relative to the presentation engine’s natural orientation, are:

    typedef enum VkSurfaceTransformFlagBitsKHR {
        VK_SURFACE_TRANSFORM_IDENTITY_BIT_KHR = 0x00000001,
        VK_SURFACE_TRANSFORM_ROTATE_90_BIT_KHR = 0x00000002,
        VK_SURFACE_TRANSFORM_ROTATE_180_BIT_KHR = 0x00000004,
        VK_SURFACE_TRANSFORM_ROTATE_270_BIT_KHR = 0x00000008,
        VK_SURFACE_TRANSFORM_HORIZONTAL_MIRROR_BIT_KHR = 0x00000010,
        VK_SURFACE_TRANSFORM_HORIZONTAL_MIRROR_ROTATE_90_BIT_KHR = 0x00000020,
        VK_SURFACE_TRANSFORM_HORIZONTAL_MIRROR_ROTATE_180_BIT_KHR = 0x00000040,
        VK_SURFACE_TRANSFORM_HORIZONTAL_MIRROR_ROTATE_270_BIT_KHR = 0x00000080,
        VK_SURFACE_TRANSFORM_INHERIT_BIT_KHR = 0x00000100,
        VK_SURFACE_TRANSFORM_FLAG_BITS_MAX_ENUM_KHR = 0x7FFFFFFF
    } VkSurfaceTransformFlagBitsKHR;

- `VK_SURFACE_TRANSFORM_IDENTITY_BIT_KHR` specifies that image content is presented without being transformed.

- `VK_SURFACE_TRANSFORM_ROTATE_90_BIT_KHR` specifies that image content is rotated 90 degrees clockwise.

- `VK_SURFACE_TRANSFORM_ROTATE_180_BIT_KHR` specifies that image content is rotated 180 degrees clockwise.

- `VK_SURFACE_TRANSFORM_ROTATE_270_BIT_KHR` specifies that image content is rotated 270 degrees clockwise.

- `VK_SURFACE_TRANSFORM_HORIZONTAL_MIRROR_BIT_KHR` specifies that image content is mirrored horizontally.

- `VK_SURFACE_TRANSFORM_HORIZONTAL_MIRROR_ROTATE_90_BIT_KHR` specifies that image content is mirrored horizontally, then rotated 90 degrees clockwise.

- `VK_SURFACE_TRANSFORM_HORIZONTAL_MIRROR_ROTATE_180_BIT_KHR` specifies that image content is mirrored horizontally, then rotated 180 degrees clockwise.

- `VK_SURFACE_TRANSFORM_HORIZONTAL_MIRROR_ROTATE_270_BIT_KHR` specifies that image content is mirrored horizontally, then rotated 270 degrees clockwise.

- `VK_SURFACE_TRANSFORM_INHERIT_BIT_KHR` specifies that the presentation transform is not specified, and is instead determined by platform-specific considerations and mechanisms outside Vulkan.

    typedef VkFlags VkSurfaceTransformFlagsKHR;

`VkSurfaceTransformFlagsKHR` is a bitmask type for setting a mask of zero or more VkSurfaceTransformFlagBitsKHR.

The `supportedCompositeAlpha` member is of type VkCompositeAlphaFlagBitsKHR, which contains the following values:

    typedef enum VkCompositeAlphaFlagBitsKHR {
        VK_COMPOSITE_ALPHA_OPAQUE_BIT_KHR = 0x00000001,
        VK_COMPOSITE_ALPHA_PRE_MULTIPLIED_BIT_KHR = 0x00000002,
        VK_COMPOSITE_ALPHA_POST_MULTIPLIED_BIT_KHR = 0x00000004,
        VK_COMPOSITE_ALPHA_INHERIT_BIT_KHR = 0x00000008,
        VK_COMPOSITE_ALPHA_FLAG_BITS_MAX_ENUM_KHR = 0x7FFFFFFF
    } VkCompositeAlphaFlagBitsKHR;

These values are described as follows:

- `VK_COMPOSITE_ALPHA_OPAQUE_BIT_KHR`: The alpha channel, if it exists, of the images is ignored in the compositing process. Instead, the image is treated as if it has a constant alpha of 1.0.

- `VK_COMPOSITE_ALPHA_PRE_MULTIPLIED_BIT_KHR`: The alpha channel, if it exists, of the images is respected in the compositing process. The non-alpha channels of the image are expected to already be multiplied by the alpha channel by the application.

- `VK_COMPOSITE_ALPHA_POST_MULTIPLIED_BIT_KHR`: The alpha channel, if it exists, of the images is respected in the compositing process. The non-alpha channels of the image are not expected to already be multiplied by the alpha channel by the application; instead, the compositor will multiply the non-alpha channels of the image by the alpha channel during compositing.

- `VK_COMPOSITE_ALPHA_INHERIT_BIT_KHR`: The way in which the presentation engine treats the alpha channel in the images is unknown to the Vulkan API. Instead, the application is responsible for setting the composite alpha blending mode using native window system commands. If the application does not set the blending mode using native window system commands, then a platform-specific default will be used.

    typedef VkFlags VkCompositeAlphaFlagsKHR;

`VkCompositeAlphaFlagsKHR` is a bitmask type for setting a mask of zero or more VkCompositeAlphaFlagBitsKHR.

#### 32.5.2. Surface Format Support

To query the supported swapchain format-color space pairs for a surface, call:

    VkResult vkGetPhysicalDeviceSurfaceFormatsKHR(
        VkPhysicalDevice                            physicalDevice,
        VkSurfaceKHR                                surface,
        uint32_t*                                   pSurfaceFormatCount,
        VkSurfaceFormatKHR*                         pSurfaceFormats);

- `physicalDevice` is the physical device that will be associated with the swapchain to be created, as described for vkCreateSwapchainKHR.

- `surface` is the surface that will be associated with the swapchain.

- `pSurfaceFormatCount` is a pointer to an integer related to the number of format pairs available or queried, as described below.

- `pSurfaceFormats` is either `NULL` or a pointer to an array of `VkSurfaceFormatKHR` structures.

If `pSurfaceFormats` is `NULL`, then the number of format pairs supported for the given `surface` is returned in `pSurfaceFormatCount`. Otherwise, `pSurfaceFormatCount` must point to a variable set by the user to the number of elements in the `pSurfaceFormats` array, and on return the variable is overwritten with the number of structures actually written to `pSurfaceFormats`. If the value of `pSurfaceFormatCount` is less than the number of format pairs supported, at most `pSurfaceFormatCount` structures will be written. If `pSurfaceFormatCount` is smaller than the number of format pairs supported for the given `surface`, `VK_INCOMPLETE` will be returned instead of `VK_SUCCESS` to indicate that not all the available values were returned.

The number of format pairs supported must be greater than or equal to 1. `pSurfaceFormats` must not contain an entry whose value for `format` is `VK_FORMAT_UNDEFINED`.

If `pSurfaceFormats` includes an entry whose value for `colorSpace` is `VK_COLOR_SPACE_SRGB_NONLINEAR_KHR` and whose value for `format` is a UNORM (or SRGB) format and the corresponding SRGB (or UNORM) format is a color renderable format for `VK_IMAGE_TILING_OPTIMAL`, then `pSurfaceFormats` must also contain an entry with the same value for `colorSpace` and `format` equal to the corresponding SRGB (or UNORM) format.

Valid Usage

- `surface` must be supported by `physicalDevice`, as reported by vkGetPhysicalDeviceSurfaceSupportKHR or an equivalent platform-specific mechanism.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `surface` must be a valid VkSurfaceKHR handle

- `pSurfaceFormatCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pSurfaceFormatCount` is not `0`, and `pSurfaceFormats` is not `NULL`, `pSurfaceFormats` must be a valid pointer to an array of `pSurfaceFormatCount` VkSurfaceFormatKHR structures

- Both of `physicalDevice`, and `surface` must have been created, allocated, or retrieved from the same VkInstance

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_SURFACE_LOST_KHR`

The `VkSurfaceFormatKHR` structure is defined as:

    typedef struct VkSurfaceFormatKHR {
        VkFormat           format;
        VkColorSpaceKHR    colorSpace;
    } VkSurfaceFormatKHR;

- `format` is a VkFormat that is compatible with the specified surface.

- `colorSpace` is a presentation VkColorSpaceKHR that is compatible with the surface.

To query the supported swapchain format tuples for a surface, call:

    VkResult vkGetPhysicalDeviceSurfaceFormats2KHR(
        VkPhysicalDevice                            physicalDevice,
        const VkPhysicalDeviceSurfaceInfo2KHR*      pSurfaceInfo,
        uint32_t*                                   pSurfaceFormatCount,
        VkSurfaceFormat2KHR*                        pSurfaceFormats);

- `physicalDevice` is the physical device that will be associated with the swapchain to be created, as described for vkCreateSwapchainKHR.

- `pSurfaceInfo` is a pointer to a VkPhysicalDeviceSurfaceInfo2KHR structure describing the surface and other fixed parameters that would be consumed by vkCreateSwapchainKHR.

- `pSurfaceFormatCount` is a pointer to an integer related to the number of format tuples available or queried, as described below.

- `pSurfaceFormats` is either `NULL` or a pointer to an array of VkSurfaceFormat2KHR structures.

vkGetPhysicalDeviceSurfaceFormats2KHR behaves similarly to vkGetPhysicalDeviceSurfaceFormatsKHR, with the ability to be extended via `pNext` chains.

If `pSurfaceFormats` is `NULL`, then the number of format tuples supported for the given `surface` is returned in `pSurfaceFormatCount`. Otherwise, `pSurfaceFormatCount` must point to a variable set by the user to the number of elements in the `pSurfaceFormats` array, and on return the variable is overwritten with the number of structures actually written to `pSurfaceFormats`. If the value of `pSurfaceFormatCount` is less than the number of format tuples supported, at most `pSurfaceFormatCount` structures will be written. If `pSurfaceFormatCount` is smaller than the number of format tuples supported for the surface parameters described in `pSurfaceInfo`, `VK_INCOMPLETE` will be returned instead of `VK_SUCCESS` to indicate that not all the available values were returned.

Valid Usage

- `pSurfaceInfo->surface` must be supported by `physicalDevice`, as reported by vkGetPhysicalDeviceSurfaceSupportKHR or an equivalent platform-specific mechanism.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pSurfaceInfo` must be a valid pointer to a valid VkPhysicalDeviceSurfaceInfo2KHR structure

- `pSurfaceFormatCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pSurfaceFormatCount` is not `0`, and `pSurfaceFormats` is not `NULL`, `pSurfaceFormats` must be a valid pointer to an array of `pSurfaceFormatCount` VkSurfaceFormat2KHR structures

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_SURFACE_LOST_KHR`

The `VkSurfaceFormat2KHR` structure is defined as:

    typedef struct VkSurfaceFormat2KHR {
        VkStructureType       sType;
        void*                 pNext;
        VkSurfaceFormatKHR    surfaceFormat;
    } VkSurfaceFormat2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `surfaceFormat` is a VkSurfaceFormatKHR structure describing a format-color space pair that is compatible with the specified surface.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SURFACE_FORMAT_2_KHR`

- `pNext` must be `NULL`

While the `format` of a presentable image refers to the encoding of each pixel, the `colorSpace` determines how the presentation engine interprets the pixel values. A color space in this document refers to a specific color space (defined by the chromaticities of its primaries and a white point in CIE Lab), and a transfer function that is applied before storing or transmitting color data in the given color space.

Possible values of VkSurfaceFormatKHR::`colorSpace`, specifying supported color spaces of a presentation engine, are:

    typedef enum VkColorSpaceKHR {
        VK_COLOR_SPACE_SRGB_NONLINEAR_KHR = 0,
        VK_COLOR_SPACE_DISPLAY_P3_NONLINEAR_EXT = 1000104001,
        VK_COLOR_SPACE_EXTENDED_SRGB_LINEAR_EXT = 1000104002,
        VK_COLOR_SPACE_DISPLAY_P3_LINEAR_EXT = 1000104003,
        VK_COLOR_SPACE_DCI_P3_NONLINEAR_EXT = 1000104004,
        VK_COLOR_SPACE_BT709_LINEAR_EXT = 1000104005,
        VK_COLOR_SPACE_BT709_NONLINEAR_EXT = 1000104006,
        VK_COLOR_SPACE_BT2020_LINEAR_EXT = 1000104007,
        VK_COLOR_SPACE_HDR10_ST2084_EXT = 1000104008,
        VK_COLOR_SPACE_DOLBYVISION_EXT = 1000104009,
        VK_COLOR_SPACE_HDR10_HLG_EXT = 1000104010,
        VK_COLOR_SPACE_ADOBERGB_LINEAR_EXT = 1000104011,
        VK_COLOR_SPACE_ADOBERGB_NONLINEAR_EXT = 1000104012,
        VK_COLOR_SPACE_PASS_THROUGH_EXT = 1000104013,
        VK_COLOR_SPACE_EXTENDED_SRGB_NONLINEAR_EXT = 1000104014,
        VK_COLOR_SPACE_DISPLAY_NATIVE_AMD = 1000213000,
        VK_COLORSPACE_SRGB_NONLINEAR_KHR = VK_COLOR_SPACE_SRGB_NONLINEAR_KHR,
        VK_COLOR_SPACE_DCI_P3_LINEAR_EXT = VK_COLOR_SPACE_DISPLAY_P3_LINEAR_EXT,
        VK_COLOR_SPACE_MAX_ENUM_KHR = 0x7FFFFFFF
    } VkColorSpaceKHR;

- `VK_COLOR_SPACE_SRGB_NONLINEAR_KHR` specifies support for the sRGB color space.

- `VK_COLOR_SPACE_DISPLAY_P3_NONLINEAR_EXT` specifies support for the Display-P3 color space to be displayed using an sRGB-like EOTF (defined below).

- `VK_COLOR_SPACE_EXTENDED_SRGB_LINEAR_EXT` specifies support for the extended sRGB color space to be displayed using a linear EOTF.

- `VK_COLOR_SPACE_EXTENDED_SRGB_NONLINEAR_EXT` specifies support for the extended sRGB color space to be displayed using an sRGB EOTF.

- `VK_COLOR_SPACE_DISPLAY_P3_LINEAR_EXT` specifies support for the Display-P3 color space to be displayed using a linear EOTF.

- `VK_COLOR_SPACE_DCI_P3_NONLINEAR_EXT` specifies support for the DCI-P3 color space to be displayed using the DCI-P3 EOTF. Note that values in such an image are interpreted as XYZ encoded color data by the presentation engine.

- `VK_COLOR_SPACE_BT709_LINEAR_EXT` specifies support for the BT709 color space to be displayed using a linear EOTF.

- `VK_COLOR_SPACE_BT709_NONLINEAR_EXT` specifies support for the BT709 color space to be displayed using the SMPTE 170M EOTF.

- `VK_COLOR_SPACE_BT2020_LINEAR_EXT` specifies support for the BT2020 color space to be displayed using a linear EOTF.

- `VK_COLOR_SPACE_HDR10_ST2084_EXT` specifies support for the HDR10 (BT2020 color) space to be displayed using the SMPTE ST2084 Perceptual Quantizer (PQ) EOTF.

- `VK_COLOR_SPACE_DOLBYVISION_EXT` specifies support for the Dolby Vision (BT2020 color space), proprietary encoding, to be displayed using the SMPTE ST2084 EOTF.

- `VK_COLOR_SPACE_HDR10_HLG_EXT` specifies support for the HDR10 (BT2020 color space) to be displayed using the Hybrid Log Gamma (HLG) EOTF.

- `VK_COLOR_SPACE_ADOBERGB_LINEAR_EXT` specifies support for the AdobeRGB color space to be displayed using a linear EOTF.

- `VK_COLOR_SPACE_ADOBERGB_NONLINEAR_EXT` specifies support for the AdobeRGB color space to be displayed using the Gamma 2.2 EOTF.

- `VK_COLOR_SPACE_PASS_THROUGH_EXT` specifies that color components are used “as is”. This is intended to allow applications to supply data for color spaces not described here.

- `VK_COLOR_SPACE_DISPLAY_NATIVE_AMD` specifies support for the display’s native color space. This matches the color space expectations of AMD’s FreeSync2 standard, for displays supporting it.

| Note In the initial release of the `VK_KHR_surface` and `VK_KHR_swapchain` extensions, the token `VK_COLORSPACE_SRGB_NONLINEAR_KHR` was used. Starting in the 2016-05-13 updates to the extension branches, matching release 1.0.13 of the core API specification, `VK_COLOR_SPACE_SRGB_NONLINEAR_KHR` is used instead for consistency with Vulkan naming rules. The older enum is still available for backwards compatibility.

| Note In older versions of this extension `VK_COLOR_SPACE_DISPLAY_P3_LINEAR_EXT` was misnamed `VK_COLOR_SPACE_DCI_P3_LINEAR_EXT`. This has been updated to indicate that it uses RGB color encoding, not XYZ. The old name is deprecated but is maintained for backwards compatibility.

The color components of non-linear color space swap chain images must have had the appropriate transfer function applied. The color space selected for the swap chain image will not affect the processing of data written into the image by the implementation. Vulkan requires that all implementations support the sRGB transfer function by use of an SRGB pixel format. Other transfer functions, such as SMPTE 170M or SMPTE2084, can be performed by the application shader. This extension defines enums for VkColorSpaceKHR that correspond to the following color spaces:

Table 42. Color Spaces and Attributes
Name | Red Primary | Green Primary | Blue Primary | White-point | Transfer function
--- | --- | --- | --- | --- | ---
DCI-P3 | 1.000, 0.000 | 0.000, 1.000 | 0.000, 0.000 | 0.3333, 0.3333 | DCI P3
Display-P3 | 0.680, 0.320 | 0.265, 0.690 | 0.150, 0.060 | 0.3127, 0.3290 (D65) | Display-P3
BT709 | 0.640, 0.330 | 0.300, 0.600 | 0.150, 0.060 | 0.3127, 0.3290 (D65) | ITU (SMPTE 170M)
sRGB | 0.640, 0.330 | 0.300, 0.600 | 0.150, 0.060 | 0.3127, 0.3290 (D65) | sRGB
extended sRGB | 0.640, 0.330 | 0.300, 0.600 | 0.150, 0.060 | 0.3127, 0.3290 (D65) | extended sRGB
HDR10_ST2084 | 0.708, 0.292 | 0.170, 0.797 | 0.131, 0.046 | 0.3127, 0.3290 (D65) | ST2084 PQ
DOLBYVISION | 0.708, 0.292 | 0.170, 0.797 | 0.131, 0.046 | 0.3127, 0.3290 (D65) | ST2084 PQ
HDR10_HLG | 0.708, 0.292 | 0.170, 0.797 | 0.131, 0.046 | 0.3127, 0.3290 (D65) | HLG
AdobeRGB | 0.640, 0.330 | 0.210, 0.710 | 0.150, 0.060 | 0.3127, 0.3290 (D65) | AdobeRGB

The transfer functions are described in the “Transfer Functions” chapter of the Khronos Data Format Specification.

Except Display-P3 OETF, which is:

\[\begin{aligned} E & = \begin{cases} 1.055 \times L^{1 \over 2.4} - 0.055 & \text{for}\ 0.0030186 \leq L \leq 1 \\ 12.92 \times L & \text{for}\ 0 \leq L < 0.0030186 \end{cases} \end{aligned}\]

where L is the linear value of a color channel and E is the encoded value (as stored in the image in memory).

| Note For most uses, the sRGB OETF is equivalent.

#### 32.5.3. Surface Presentation Mode Support

To query the supported presentation modes for a surface, call:

    VkResult vkGetPhysicalDeviceSurfacePresentModesKHR(
        VkPhysicalDevice                            physicalDevice,
        VkSurfaceKHR                                surface,
        uint32_t*                                   pPresentModeCount,
        VkPresentModeKHR*                           pPresentModes);

- `physicalDevice` is the physical device that will be associated with the swapchain to be created, as described for vkCreateSwapchainKHR.

- `surface` is the surface that will be associated with the swapchain.

- `pPresentModeCount` is a pointer to an integer related to the number of presentation modes available or queried, as described below.

- `pPresentModes` is either `NULL` or a pointer to an array of VkPresentModeKHR values, indicating the supported presentation modes.

If `pPresentModes` is `NULL`, then the number of presentation modes supported for the given `surface` is returned in `pPresentModeCount`. Otherwise, `pPresentModeCount` must point to a variable set by the user to the number of elements in the `pPresentModes` array, and on return the variable is overwritten with the number of values actually written to `pPresentModes`. If the value of `pPresentModeCount` is less than the number of presentation modes supported, at most `pPresentModeCount` values will be written. If `pPresentModeCount` is smaller than the number of presentation modes supported for the given `surface`, `VK_INCOMPLETE` will be returned instead of `VK_SUCCESS` to indicate that not all the available values were returned.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `surface` must be a valid VkSurfaceKHR handle

- `pPresentModeCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pPresentModeCount` is not `0`, and `pPresentModes` is not `NULL`, `pPresentModes` must be a valid pointer to an array of `pPresentModeCount` VkPresentModeKHR values

- Both of `physicalDevice`, and `surface` must have been created, allocated, or retrieved from the same VkInstance

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_SURFACE_LOST_KHR`

Alternatively, to query the supported presentation modes for a surface combined with select other fixed swapchain creation parameters, call:

    VkResult vkGetPhysicalDeviceSurfacePresentModes2EXT(
        VkPhysicalDevice                            physicalDevice,
        const VkPhysicalDeviceSurfaceInfo2KHR*      pSurfaceInfo,
        uint32_t*                                   pPresentModeCount,
        VkPresentModeKHR*                           pPresentModes);

- `physicalDevice` is the physical device that will be associated with the swapchain to be created, as described for vkCreateSwapchainKHR.

- `pSurfaceInfo` is a pointer to a VkPhysicalDeviceSurfaceInfo2KHR structure describing the surface and other fixed parameters that would be consumed by vkCreateSwapchainKHR.

- `pPresentModeCount` is a pointer to an integer related to the number of presentation modes available or queried, as described below.

- `pPresentModes` is either `NULL` or a pointer to an array of VkPresentModeKHR values, indicating the supported presentation modes.

`vkGetPhysicalDeviceSurfacePresentModes2EXT` behaves similarly to vkGetPhysicalDeviceSurfacePresentModesKHR, with the ability to specify extended inputs via chained input structures.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pSurfaceInfo` must be a valid pointer to a valid VkPhysicalDeviceSurfaceInfo2KHR structure

- `pPresentModeCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pPresentModeCount` is not `0`, and `pPresentModes` is not `NULL`, `pPresentModes` must be a valid pointer to an array of `pPresentModeCount` VkPresentModeKHR values

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_SURFACE_LOST_KHR`

Possible values of elements of the vkGetPhysicalDeviceSurfacePresentModesKHR::`pPresentModes` array, indicating the supported presentation modes for a surface, are:

    typedef enum VkPresentModeKHR {
        VK_PRESENT_MODE_IMMEDIATE_KHR = 0,
        VK_PRESENT_MODE_MAILBOX_KHR = 1,
        VK_PRESENT_MODE_FIFO_KHR = 2,
        VK_PRESENT_MODE_FIFO_RELAXED_KHR = 3,
        VK_PRESENT_MODE_SHARED_DEMAND_REFRESH_KHR = 1000111000,
        VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR = 1000111001,
        VK_PRESENT_MODE_MAX_ENUM_KHR = 0x7FFFFFFF
    } VkPresentModeKHR;

- `VK_PRESENT_MODE_IMMEDIATE_KHR` specifies that the presentation engine does not wait for a vertical blanking period to update the current image, meaning this mode may result in visible tearing. No internal queuing of presentation requests is needed, as the requests are applied immediately.

- `VK_PRESENT_MODE_MAILBOX_KHR` specifies that the presentation engine waits for the next vertical blanking period to update the current image. Tearing cannot be observed. An internal single-entry queue is used to hold pending presentation requests. If the queue is full when a new presentation request is received, the new request replaces the existing entry, and any images associated with the prior entry become available for re-use by the application. One request is removed from the queue and processed during each vertical blanking period in which the queue is non-empty.

- `VK_PRESENT_MODE_FIFO_KHR` specifies that the presentation engine waits for the next vertical blanking period to update the current image. Tearing cannot be observed. An internal queue is used to hold pending presentation requests. New requests are appended to the end of the queue, and one request is removed from the beginning of the queue and processed during each vertical blanking period in which the queue is non-empty. This is the only value of `presentMode` that is required to be supported.

- `VK_PRESENT_MODE_FIFO_RELAXED_KHR` specifies that the presentation engine generally waits for the next vertical blanking period to update the current image. If a vertical blanking period has already passed since the last update of the current image then the presentation engine does not wait for another vertical blanking period for the update, meaning this mode may result in visible tearing in this case. This mode is useful for reducing visual stutter with an application that will mostly present a new image before the next vertical blanking period, but may occasionally be late, and present a new image just after the next vertical blanking period. An internal queue is used to hold pending presentation requests. New requests are appended to the end of the queue, and one request is removed from the beginning of the queue and processed during or after each vertical blanking period in which the queue is non-empty.

- `VK_PRESENT_MODE_SHARED_DEMAND_REFRESH_KHR` specifies that the presentation engine and application have concurrent access to a single image, which is referred to as a shared presentable image. The presentation engine is only required to update the current image after a new presentation request is received. Therefore the application must make a presentation request whenever an update is required. However, the presentation engine may update the current image at any point, meaning this mode may result in visible tearing.

- `VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR` specifies that the presentation engine and application have concurrent access to a single image, which is referred to as a shared presentable image. The presentation engine periodically updates the current image on its regular refresh cycle. The application is only required to make one initial presentation request, after which the presentation engine must update the current image without any need for further presentation requests. The application can indicate the image contents have been updated by making a presentation request, but this does not guarantee the timing of when it will be updated. This mode may result in visible tearing if rendering to the image is not timed correctly.

The supported VkImageUsageFlagBits of the presentable images of a swapchain created for a surface may differ depending on the presentation mode, and can be determined as per the table below:

Table 43. Presentable image usage queries
Presentation mode | Image usage flags
--- | ---
`VK_PRESENT_MODE_IMMEDIATE_KHR` | VkSurfaceCapabilitiesKHR::`supportedUsageFlags`
`VK_PRESENT_MODE_MAILBOX_KHR` | VkSurfaceCapabilitiesKHR::`supportedUsageFlags`
`VK_PRESENT_MODE_FIFO_KHR` | VkSurfaceCapabilitiesKHR::`supportedUsageFlags`
`VK_PRESENT_MODE_FIFO_RELAXED_KHR` | VkSurfaceCapabilitiesKHR::`supportedUsageFlags`
`VK_PRESENT_MODE_SHARED_DEMAND_REFRESH_KHR` | VkSharedPresentSurfaceCapabilitiesKHR::`sharedPresentSupportedUsageFlags`
`VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR` | VkSharedPresentSurfaceCapabilitiesKHR::`sharedPresentSupportedUsageFlags`

| Note For reference, the mode indicated by `VK_PRESENT_MODE_FIFO_KHR` is equivalent to the behavior of {wgl|glX|egl}SwapBuffers with a swap interval of 1, while the mode indicated by `VK_PRESENT_MODE_FIFO_RELAXED_KHR` is equivalent to the behavior of {wgl|glX}SwapBuffers with a swap interval of -1 (from the {WGL|GLX}_EXT_swap_control_tear extensions).

### 32.6. Full Screen Exclusive Control

Swapchains created with `fullScreenExclusive` set to `VK_FULL_SCREEN_EXCLUSIVE_APPLICATION_CONTROLLED_EXT` must acquire and release exclusive full-screen access explicitly, using the following commands.

To acquire exclusive full-screen access for a swapchain, call:

    VkResult vkAcquireFullScreenExclusiveModeEXT(
        VkDevice                                    device,
        VkSwapchainKHR                              swapchain);

- `device` is the device associated with `swapchain`.

- `swapchain` is the swapchain to acquire exclusive full-screen access for.

Valid Usage

- `swapchain` must not be in the retired state

- `swapchain` must be a swapchain created with a VkSurfaceFullScreenExclusiveInfoEXT structure, with `fullScreenExclusive` set to `VK_FULL_SCREEN_EXCLUSIVE_APPLICATION_CONTROLLED_EXT`

- `swapchain` must not currently have exclusive full-screen access

A return value of `VK_SUCCESS` indicates that the `swapchain` successfully acquired exclusive full-screen access. The swapchain will retain this exclusivity until either the application releases exclusive full-screen access with vkReleaseFullScreenExclusiveModeEXT, destroys the swapchain, or if any of the swapchain commands return `VK_ERROR_FULL_SCREEN_EXCLUSIVE_MODE_LOST_EXT` indicating that the mode was lost because of platform-specific changes.

If the swapchain was unable to acquire exclusive full-screen access to the display then `VK_ERROR_INITIALIZATION_FAILED` is returned. An application can attempt to acquire exclusive full-screen access again for the same swapchain even if this command fails, or if `VK_ERROR_FULL_SCREEN_EXCLUSIVE_MODE_LOST_EXT` has been returned by a swapchain command.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `swapchain` must be a valid VkSwapchainKHR handle

- Both of `device`, and `swapchain` must have been created, allocated, or retrieved from the same VkInstance

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_INITIALIZATION_FAILED`

  - `VK_ERROR_SURFACE_LOST_KHR`

To release exclusive full-screen access from a swapchain, call:

    VkResult vkReleaseFullScreenExclusiveModeEXT(
        VkDevice                                    device,
        VkSwapchainKHR                              swapchain);

- `device` is the device associated with `swapchain`.

- `swapchain` is the swapchain to release exclusive full-screen access from.

| Note Applications will not be able to present to `swapchain` after this call until exclusive full-screen access is reacquired. This is usually useful to handle when an application is minimised or otherwise intends to stop presenting for a time.

Valid Usage

- `swapchain` must not be in the retired state

- `swapchain` must be a swapchain created with a VkSurfaceFullScreenExclusiveInfoEXT structure, with `fullScreenExclusive` set to `VK_FULL_SCREEN_EXCLUSIVE_APPLICATION_CONTROLLED_EXT`

### 32.7. Device Group Queries

A logical device that represents multiple physical devices may support presenting from images on more than one physical device, or combining images from multiple physical devices.

To query these capabilities, call:

    VkResult vkGetDeviceGroupPresentCapabilitiesKHR(
        VkDevice                                    device,
        VkDeviceGroupPresentCapabilitiesKHR*        pDeviceGroupPresentCapabilities);

- `device` is the logical device.

- `pDeviceGroupPresentCapabilities` is a pointer to a VkDeviceGroupPresentCapabilitiesKHR structure in which the device’s capabilities are returned.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pDeviceGroupPresentCapabilities` must be a valid pointer to a VkDeviceGroupPresentCapabilitiesKHR structure

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkDeviceGroupPresentCapabilitiesKHR` structure is defined as:

    typedef struct VkDeviceGroupPresentCapabilitiesKHR {
        VkStructureType                     sType;
        const void*                         pNext;
        uint32_t                            presentMask[VK_MAX_DEVICE_GROUP_SIZE];
        VkDeviceGroupPresentModeFlagsKHR    modes;
    } VkDeviceGroupPresentCapabilitiesKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `presentMask` is an array of `VK_MAX_DEVICE_GROUP_SIZE` `uint32_t` masks, where the mask at element i is non-zero if physical device i has a presentation engine, and where bit j is set in element i if physical device i can present swapchain images from physical device j. If element i is non-zero, then bit i must be set.

- `modes` is a bitmask of VkDeviceGroupPresentModeFlagBitsKHR indicating which device group presentation modes are supported.

`modes` always has `VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_BIT_KHR` set.

The present mode flags are also used when presenting an image, in VkDeviceGroupPresentInfoKHR::`mode`.

If a device group only includes a single physical device, then `modes` must equal `VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_BIT_KHR`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEVICE_GROUP_PRESENT_CAPABILITIES_KHR`

- `pNext` must be `NULL`

Bits which may be set in VkDeviceGroupPresentCapabilitiesKHR::`modes` to indicate which device group presentation modes are supported are:

    typedef enum VkDeviceGroupPresentModeFlagBitsKHR {
        VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_BIT_KHR = 0x00000001,
        VK_DEVICE_GROUP_PRESENT_MODE_REMOTE_BIT_KHR = 0x00000002,
        VK_DEVICE_GROUP_PRESENT_MODE_SUM_BIT_KHR = 0x00000004,
        VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_MULTI_DEVICE_BIT_KHR = 0x00000008,
        VK_DEVICE_GROUP_PRESENT_MODE_FLAG_BITS_MAX_ENUM_KHR = 0x7FFFFFFF
    } VkDeviceGroupPresentModeFlagBitsKHR;

- `VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_BIT_KHR` specifies that any physical device with a presentation engine can present its own swapchain images.

- `VK_DEVICE_GROUP_PRESENT_MODE_REMOTE_BIT_KHR` specifies that any physical device with a presentation engine can present swapchain images from any physical device in its `presentMask`.

- `VK_DEVICE_GROUP_PRESENT_MODE_SUM_BIT_KHR` specifies that any physical device with a presentation engine can present the sum of swapchain images from any physical devices in its `presentMask`.

- `VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_MULTI_DEVICE_BIT_KHR` specifies that multiple physical devices with a presentation engine can each present their own swapchain images.

    typedef VkFlags VkDeviceGroupPresentModeFlagsKHR;

`VkDeviceGroupPresentModeFlagsKHR` is a bitmask type for setting a mask of zero or more VkDeviceGroupPresentModeFlagBitsKHR.

Some surfaces may not be capable of using all the device group present modes.

To query the supported device group present modes for a particular surface, call:

    VkResult vkGetDeviceGroupSurfacePresentModesKHR(
        VkDevice                                    device,
        VkSurfaceKHR                                surface,
        VkDeviceGroupPresentModeFlagsKHR*           pModes);

- `device` is the logical device.

- `surface` is the surface.

- `pModes` is a pointer to a VkDeviceGroupPresentModeFlagsKHR in which the supported device group present modes for the surface are returned.

The modes returned by this command are not invariant, and may change in response to the surface being moved, resized, or occluded. These modes must be a subset of the modes returned by vkGetDeviceGroupPresentCapabilitiesKHR.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `surface` must be a valid VkSurfaceKHR handle

- `pModes` must be a valid pointer to a VkDeviceGroupPresentModeFlagsKHR value

- Both of `device`, and `surface` must have been created, allocated, or retrieved from the same VkInstance

Host Synchronization

- Host access to `surface` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_SURFACE_LOST_KHR`

Alternatively, to query the supported device group presentation modes for a surface combined with select other fixed swapchain creation parameters, call:

    VkResult vkGetDeviceGroupSurfacePresentModes2EXT(
        VkDevice                                    device,
        const VkPhysicalDeviceSurfaceInfo2KHR*      pSurfaceInfo,
        VkDeviceGroupPresentModeFlagsKHR*           pModes);

- `device` is the logical device.

- `pSurfaceInfo` is a pointer to a VkPhysicalDeviceSurfaceInfo2KHR structure describing the surface and other fixed parameters that would be consumed by vkCreateSwapchainKHR.

- `pModes` is a pointer to a VkDeviceGroupPresentModeFlagsKHR in which the supported device group present modes for the surface are returned.

`vkGetDeviceGroupSurfacePresentModes2EXT` behaves similarly to vkGetDeviceGroupSurfacePresentModesKHR, with the ability to specify extended inputs via chained input structures.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pSurfaceInfo` must be a valid pointer to a valid VkPhysicalDeviceSurfaceInfo2KHR structure

- `pModes` must be a valid pointer to a VkDeviceGroupPresentModeFlagsKHR value

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_SURFACE_LOST_KHR`

When using `VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_MULTI_DEVICE_BIT_KHR`, the application may need to know which regions of the surface are used when presenting locally on each physical device. Presentation of swapchain images to this surface need only have valid contents in the regions returned by this command.

To query a set of rectangles used in presentation on the physical device, call:

    VkResult vkGetPhysicalDevicePresentRectanglesKHR(
        VkPhysicalDevice                            physicalDevice,
        VkSurfaceKHR                                surface,
        uint32_t*                                   pRectCount,
        VkRect2D*                                   pRects);

- `physicalDevice` is the physical device.

- `surface` is the surface.

- `pRectCount` is a pointer to an integer related to the number of rectangles available or queried, as described below.

- `pRects` is either `NULL` or a pointer to an array of VkRect2D structures.

If `pRects` is `NULL`, then the number of rectangles used when presenting the given `surface` is returned in `pRectCount`. Otherwise, `pRectCount` must point to a variable set by the user to the number of elements in the `pRects` array, and on return the variable is overwritten with the number of structures actually written to `pRects`. If the value of `pRectCount` is less than the number of rectangles, at most `pRectCount` structures will be written. If `pRectCount` is smaller than the number of rectangles used for the given `surface`, `VK_INCOMPLETE` will be returned instead of `VK_SUCCESS` to indicate that not all the available values were returned.

The values returned by this command are not invariant, and may change in response to the surface being moved, resized, or occluded.

The rectangles returned by this command must not overlap.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `surface` must be a valid VkSurfaceKHR handle

- `pRectCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pRectCount` is not `0`, and `pRects` is not `NULL`, `pRects` must be a valid pointer to an array of `pRectCount` VkRect2D structures

- Both of `physicalDevice`, and `surface` must have been created, allocated, or retrieved from the same VkInstance

Host Synchronization

- Host access to `surface` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

### 32.8. Display Timing Queries

Traditional game and real-time-animation applications frequently use `VK_PRESENT_MODE_FIFO_KHR` so that presentable images are updated during the vertical blanking period of a given refresh cycle (RC) of the presentation engine’s display. This avoids the visual anomaly known as tearing.

However, synchronizing the presentation of images with the RC does not prevent all forms of visual anomalies. Stuttering occurs when the geometry for each presentable image is not accurately positioned for when that image will be displayed. The geometry may appear to move too little some RCs, and too much for others. Sometimes the animation appears to freeze, when the same image is used for more than one RC.

In order to minimize stuttering, an application needs to correctly position their geometry for when the presentable image will be displayed to the user. To accomplish this, applications need various timing information about the presentation engine’s display. They need to know when presentable images were actually presented, and when they could have been presented. Applications also need to tell the presentation engine to display an image no sooner than a given time. This can allow the application’s animation to look smooth to the user, with no stuttering. The `VK_GOOGLE_display_timing` extension allows an application to satisfy these needs.

The presentation engine’s display typically refreshes the pixels that are displayed to the user on a periodic basis. The period may be fixed or variable. In many cases, the presentation engine is associated with fixed refresh rate (FRR) display technology, with a fixed refresh rate (RR, e.g. 60Hz). In some cases, the presentation engine is associated with variable refresh rate (VRR) display technology, where each refresh cycle (RC) can vary in length. This extension treats VRR displays as if they are FRR.

To query the duration of a refresh cycle (RC) for the presentation engine’s display, call:

    VkResult vkGetRefreshCycleDurationGOOGLE(
        VkDevice                                    device,
        VkSwapchainKHR                              swapchain,
        VkRefreshCycleDurationGOOGLE*               pDisplayTimingProperties);

- `device` is the device associated with `swapchain`.

- `swapchain` is the swapchain to obtain the refresh duration for.

- `pDisplayTimingProperties` is a pointer to a `VkRefreshCycleDurationGOOGLE` structure.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `swapchain` must be a valid VkSwapchainKHR handle

- `pDisplayTimingProperties` must be a valid pointer to a VkRefreshCycleDurationGOOGLE structure

- Both of `device`, and `swapchain` must have been created, allocated, or retrieved from the same VkInstance

Host Synchronization

- Host access to `swapchain` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_DEVICE_LOST`

  - `VK_ERROR_SURFACE_LOST_KHR`

The `VkRefreshCycleDurationGOOGLE` structure is defined as:

    typedef struct VkRefreshCycleDurationGOOGLE {
        uint64_t    refreshDuration;
    } VkRefreshCycleDurationGOOGLE;

- `refreshDuration` is the number of nanoseconds from the start of one refresh cycle to the next.

| Note The rate at which an application renders and presents new images is known as the image present rate (IPR, aka frame rate). The inverse of IPR, or the duration between each image present, is the image present duration (IPD). In order to provide a smooth, stutter-free animation, an application will want its IPD to be a multiple of `refreshDuration`. For example, if a display has a 60Hz refresh rate, `refreshDuration` will be a value in nanoseconds that is approximately equal to 16.67ms. In such a case, an application will want an IPD of 16.67ms (1X multiplier of `refreshDuration`), or 33.33ms (2X multiplier of `refreshDuration`), or 50.0ms (3X multiplier of `refreshDuration`), etc. In order to determine a target IPD for a display (i.e. a multiple of `refreshDuration`), an application needs to determine when its images are actually displayed. Let’s say that an application has an initial target IPD of 16.67ms (1X multiplier of `refreshDuration`). It will therefore position the geometry of a new image 16.67ms later than the previous image. Let’s say that this application is running on slower hardware, so that it actually takes 20ms to render each new image. This will create visual anomalies, because the images will not be displayed to the user every 16.67ms, nor every 20ms. In this case, it is better for the application to adjust its target IPD to 33.33ms (i.e. a 2X multiplier of `refreshDuration`), and tell the presentation engine to not present images any sooner than every 33.33ms. This will allow the geometry to be correctly positioned for each presentable image. Adjustments to an application’s IPD may be needed because different views of an application’s geometry can take different amounts of time to render. For example, looking at the sky may take less time to render than looking at multiple, complex items in a room. In general, it is good to not frequently change IPD, as that can cause visual anomalies. Adjustments to a larger IPD because of late images should happen quickly, but adjustments to a smaller IPD should only happen if the `actualPresentTime` and `earliestPresentTime` members of the VkPastPresentationTimingGOOGLE structure are consistently different, and if `presentMargin` is consistently large, over multiple images.

The implementation will maintain a limited amount of history of timing information about previous presents. Because of the asynchronous nature of the presentation engine, the timing information for a given vkQueuePresentKHR command will become available some time later. These time values can be asynchronously queried, and will be returned if available. All time values are in nanoseconds, relative to a monotonically-increasing clock (e.g. `CLOCK_MONOTONIC` (see clock_gettime(2)) on Android and Linux).

To asynchronously query the presentation engine, for newly-available timing information about one or more previous presents to a given swapchain, call:

    VkResult vkGetPastPresentationTimingGOOGLE(
        VkDevice                                    device,
        VkSwapchainKHR                              swapchain,
        uint32_t*                                   pPresentationTimingCount,
        VkPastPresentationTimingGOOGLE*             pPresentationTimings);

- `device` is the device associated with `swapchain`.

- `swapchain` is the swapchain to obtain presentation timing information duration for.

- `pPresentationTimingCount` is a pointer to an integer related to the number of `VkPastPresentationTimingGOOGLE` structures to query, as described below.

- `pPresentationTimings` is either `NULL` or a pointer to an array of `VkPastPresentationTimingGOOGLE` structures.

If `pPresentationTimings` is `NULL`, then the number of newly-available timing records for the given `swapchain` is returned in `pPresentationTimingCount`. Otherwise, `pPresentationTimingCount` must point to a variable set by the user to the number of elements in the `pPresentationTimings` array, and on return the variable is overwritten with the number of structures actually written to `pPresentationTimings`. If the value of `pPresentationTimingCount` is less than the number of newly-available timing records, at most `pPresentationTimingCount` structures will be written. If `pPresentationTimingCount` is smaller than the number of newly-available timing records for the given `swapchain`, `VK_INCOMPLETE` will be returned instead of `VK_SUCCESS` to indicate that not all the available values were returned.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `swapchain` must be a valid VkSwapchainKHR handle

- `pPresentationTimingCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pPresentationTimingCount` is not `0`, and `pPresentationTimings` is not `NULL`, `pPresentationTimings` must be a valid pointer to an array of `pPresentationTimingCount` VkPastPresentationTimingGOOGLE structures

- Both of `device`, and `swapchain` must have been created, allocated, or retrieved from the same VkInstance

Host Synchronization

- Host access to `swapchain` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_DEVICE_LOST`

  - `VK_ERROR_OUT_OF_DATE_KHR`

  - `VK_ERROR_SURFACE_LOST_KHR`

The `VkPastPresentationTimingGOOGLE` structure is defined as:

    typedef struct VkPastPresentationTimingGOOGLE {
        uint32_t    presentID;
        uint64_t    desiredPresentTime;
        uint64_t    actualPresentTime;
        uint64_t    earliestPresentTime;
        uint64_t    presentMargin;
    } VkPastPresentationTimingGOOGLE;

- `presentID` is an application-provided value that was given to a previous `vkQueuePresentKHR` command via VkPresentTimeGOOGLE::`presentID` (see below). It can be used to uniquely identify a previous present with the vkQueuePresentKHR command.

- `desiredPresentTime` is an application-provided value that was given to a previous vkQueuePresentKHR command via VkPresentTimeGOOGLE::`desiredPresentTime`. If non-zero, it was used by the application to indicate that an image not be presented any sooner than `desiredPresentTime`.

- `actualPresentTime` is the time when the image of the `swapchain` was actually displayed.

- `earliestPresentTime` is the time when the image of the `swapchain` could have been displayed. This may differ from `actualPresentTime` if the application requested that the image be presented no sooner than VkPresentTimeGOOGLE::`desiredPresentTime`.

- `presentMargin` is an indication of how early the `vkQueuePresentKHR` command was processed compared to how soon it needed to be processed, and still be presented at `earliestPresentTime`.

The results for a given `swapchain` and `presentID` are only returned once from `vkGetPastPresentationTimingGOOGLE`.

The application can use the `VkPastPresentationTimingGOOGLE` values to occasionally adjust its timing. For example, if `actualPresentTime` is later than expected (e.g. one `refreshDuration` late), the application may increase its target IPD to a higher multiple of `refreshDuration` (e.g. decrease its frame rate from 60Hz to 30Hz). If `actualPresentTime` and `earliestPresentTime` are consistently different, and if `presentMargin` is consistently large enough, the application may decrease its target IPD to a smaller multiple of `refreshDuration` (e.g. increase its frame rate from 30Hz to 60Hz). If `actualPresentTime` and `earliestPresentTime` are same, and if `presentMargin` is consistently high, the application may delay the start of its input-render-present loop in order to decrease the latency between user input and the corresponding present (always leaving some margin in case a new image takes longer to render than the previous image). An application that desires its target IPD to always be the same as `refreshDuration`, can also adjust features until `actualPresentTime` is never late and `presentMargin` is satisfactory.

The full `VK_GOOGLE_display_timing` extension semantics are described for swapchains created with `VK_PRESENT_MODE_FIFO_KHR`. For example, non-zero values of `VkPresentTimeGOOGLE`::`desiredPresentTime` must be honored, and `vkGetPastPresentationTimingGOOGLE` should return a `VkPastPresentationTimingGOOGLE` structure with valid values for all images presented with `vkQueuePresentKHR`. The semantics for other present modes are as follows:

- `VK_PRESENT_MODE_IMMEDIATE_KHR`. The presentation engine may ignore non-zero values of `VkPresentTimeGOOGLE`::`desiredPresentTime` in favor of presenting immediately. The value of `VkPastPresentationTimingGOOGLE`::`earliestPresentTime` must be the same as `VkPastPresentationTimingGOOGLE`::`actualPresentTime`, which should be when the presentation engine displayed the image.

- `VK_PRESENT_MODE_MAILBOX_KHR`. The intention of using this present mode with this extension is to handle cases where an image is presented late, and the next image is presented soon enough to replace it at the next vertical blanking period. For images that are displayed to the user, the value of `VkPastPresentationTimingGOOGLE`::`actualPresentTime` must be when the image was displayed. For images that are not displayed to the user, `vkGetPastPresentationTimingGOOGLE` may not return a `VkPastPresentationTimingGOOGLE` structure, or it may return a `VkPastPresentationTimingGOOGLE` structure with the value of zero for both `VkPastPresentationTimingGOOGLE`::`actualPresentTime` and `VkPastPresentationTimingGOOGLE`::`earliestPresentTime`. It is possible that an application can submit images with `VkPresentTimeGOOGLE`::`desiredPresentTime` values such that new images may not be displayed. For example, if `VkPresentTimeGOOGLE`::`desiredPresentTime` is far enough in the future that an image is not presented before `vkQueuePresentKHR` is called to present another image, the first image will not be displayed to the user. If the application continues to do that, the presentation may not display new images.

- `VK_PRESENT_MODE_FIFO_RELAXED_KHR`. For images that are presented in time to be displayed at the next vertical blanking period, the semantics are identical as for `VK_PRESENT_MODE_FIFO_RELAXED_KHR`. For images that are presented late, and are displayed after the start of the vertical blanking period (i.e. with tearing), the values of `VkPastPresentationTimingGOOGLE` may be treated as if the image was displayed at the start of the vertical blanking period, or may be treated the same as for `VK_PRESENT_MODE_IMMEDIATE_KHR`.

### 32.9. WSI Swapchain

A swapchain object (a.k.a. swapchain) provides the ability to present rendering results to a surface. Swapchain objects are represented by `VkSwapchainKHR` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkSwapchainKHR)

A swapchain is an abstraction for an array of presentable images that are associated with a surface. The presentable images are represented by `VkImage` objects created by the platform. One image (which can be an array image for multiview/stereoscopic-3D surfaces) is displayed at a time, but multiple images can be queued for presentation. An application renders to the image, and then queues the image for presentation to the surface.

A native window cannot be associated with more than one non-retired swapchain at a time. Further, swapchains cannot be created for native windows that have a non-Vulkan graphics API surface associated with them.

| Note The presentation engine is an abstraction for the platform’s compositor or display engine. The presentation engine may be synchronous or asynchronous with respect to the application and/or logical device. Some implementations may use the device’s graphics queue or dedicated presentation hardware to perform presentation.

The presentable images of a swapchain are owned by the presentation engine. An application can acquire use of a presentable image from the presentation engine. Use of a presentable image must occur only after the image is returned by `vkAcquireNextImageKHR`, and before it is presented by `vkQueuePresentKHR`. This includes transitioning the image layout and rendering commands.

An application can acquire use of a presentable image with `vkAcquireNextImageKHR`. After acquiring a presentable image and before modifying it, the application must use a synchronization primitive to ensure that the presentation engine has finished reading from the image. The application can then transition the image’s layout, queue rendering commands to it, etc. Finally, the application presents the image with `vkQueuePresentKHR`, which releases the acquisition of the image.

The presentation engine controls the order in which presentable images are acquired for use by the application.

| Note This allows the platform to handle situations which require out-of-order return of images after presentation. At the same time, it allows the application to generate command buffers referencing all of the images in the swapchain at initialization time, rather than in its main loop.

How this all works is described below.

If a swapchain is created with `presentMode` set to either `VK_PRESENT_MODE_SHARED_DEMAND_REFRESH_KHR` or `VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR`, a single presentable image can be acquired, referred to as a shared presentable image. A shared presentable image may be concurrently accessed by the application and the presentation engine, without transitioning the image’s layout after it is initially presented.

- With `VK_PRESENT_MODE_SHARED_DEMAND_REFRESH_KHR`, the presentation engine is only required to update to the latest contents of a shared presentable image after a present. The application must call `vkQueuePresentKHR` to guarantee an update. However, the presentation engine may update from it at any time.

- With `VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR`, the presentation engine will automatically present the latest contents of a shared presentable image during every refresh cycle. The application is only required to make one initial call to `vkQueuePresentKHR`, after which the presentation engine will update from it without any need for further present calls. The application can indicate the image contents have been updated by calling `vkQueuePresentKHR`, but this does not guarantee the timing of when updates will occur.

The presentation engine may access a shared presentable image at any time after it is first presented. To avoid tearing, an application should coordinate access with the presentation engine. This requires presentation engine timing information through platform-specific mechanisms and ensuring that color attachment writes are made available during the portion of the presentation engine’s refresh cycle they are intended for.

| Note The `VK_KHR_shared_presentable_image` extension does not provide functionality for determining the timing of the presentation engine’s refresh cycles.

In order to query a swapchain’s status when rendering to a shared presentable image, call:

    VkResult vkGetSwapchainStatusKHR(
        VkDevice                                    device,
        VkSwapchainKHR                              swapchain);

- `device` is the device associated with `swapchain`.

- `swapchain` is the swapchain to query.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `swapchain` must be a valid VkSwapchainKHR handle

- Both of `device`, and `swapchain` must have been created, allocated, or retrieved from the same VkInstance

Host Synchronization

- Host access to `swapchain` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_SUBOPTIMAL_KHR`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_DEVICE_LOST`

  - `VK_ERROR_OUT_OF_DATE_KHR`

  - `VK_ERROR_SURFACE_LOST_KHR`

  - `VK_ERROR_FULL_SCREEN_EXCLUSIVE_MODE_LOST_EXT`

The possible return values for `vkGetSwapchainStatusKHR` should be interpreted as follows:

- `VK_SUCCESS` specifies the presentation engine is presenting the contents of the shared presentable image, as per the swapchain’s VkPresentModeKHR.

- `VK_SUBOPTIMAL_KHR` the swapchain no longer matches the surface properties exactly, but the presentation engine is presenting the contents of the shared presentable image, as per the swapchain’s VkPresentModeKHR.

- `VK_ERROR_OUT_OF_DATE_KHR` the surface has changed in such a way that it is no longer compatible with the swapchain.

- `VK_ERROR_SURFACE_LOST_KHR` the surface is no longer available.

| Note The swapchain state may be cached by implementations, so applications should regularly call `vkGetSwapchainStatusKHR` when using a swapchain with VkPresentModeKHR set to `VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR`.

To create a swapchain, call:

    VkResult vkCreateSwapchainKHR(
        VkDevice                                    device,
        const VkSwapchainCreateInfoKHR*             pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkSwapchainKHR*                             pSwapchain);

- `device` is the device to create the swapchain for.

- `pCreateInfo` is a pointer to a VkSwapchainCreateInfoKHR structure specifying the parameters of the created swapchain.

- `pAllocator` is the allocator used for host memory allocated for the swapchain object when there is no more specific allocator available (see Memory Allocation).

- `pSwapchain` is a pointer to a VkSwapchainKHR handle in which the created swapchain object will be returned.

If the `oldSwapchain` parameter of `pCreateInfo` is a valid swapchain, which has exclusive full-screen access, that access is released from `oldSwapchain`. If the command succeeds in this case, the newly created swapchain will automatically acquire exclusive full-screen access from `oldSwapchain`.

| Note This implicit transfer is intended to avoid exiting and entering full-screen exclusive mode, which may otherwise cause unwanted visual updates to the display.

In some cases, swapchain creation may fail if exclusive full-screen mode is requested for application control, but for some implementation-specific reason exclusive full-screen access is unavailable for the particular combination of parameters provided. If this occurs, `VK_ERROR_INITIALIZATION_FAILED` will be returned.

| Note In particular, it will fail if the `imageExtent` member of `pCreateInfo` does not match the extents of the monitor. Other reasons for failure may include the app not being set as high-dpi aware, or if the physical device and monitor are not compatible in this mode.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfo` must be a valid pointer to a valid VkSwapchainCreateInfoKHR structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pSwapchain` must be a valid pointer to a VkSwapchainKHR handle

Host Synchronization

- Host access to `pCreateInfo.surface` must be externally synchronized

- Host access to `pCreateInfo.oldSwapchain` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_DEVICE_LOST`

  - `VK_ERROR_SURFACE_LOST_KHR`

  - `VK_ERROR_NATIVE_WINDOW_IN_USE_KHR`

  - `VK_ERROR_INITIALIZATION_FAILED`

The `VkSwapchainCreateInfoKHR` structure is defined as:

    typedef struct VkSwapchainCreateInfoKHR {
        VkStructureType                  sType;
        const void*                      pNext;
        VkSwapchainCreateFlagsKHR        flags;
        VkSurfaceKHR                     surface;
        uint32_t                         minImageCount;
        VkFormat                         imageFormat;
        VkColorSpaceKHR                  imageColorSpace;
        VkExtent2D                       imageExtent;
        uint32_t                         imageArrayLayers;
        VkImageUsageFlags                imageUsage;
        VkSharingMode                    imageSharingMode;
        uint32_t                         queueFamilyIndexCount;
        const uint32_t*                  pQueueFamilyIndices;
        VkSurfaceTransformFlagBitsKHR    preTransform;
        VkCompositeAlphaFlagBitsKHR      compositeAlpha;
        VkPresentModeKHR                 presentMode;
        VkBool32                         clipped;
        VkSwapchainKHR                   oldSwapchain;
    } VkSwapchainCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkSwapchainCreateFlagBitsKHR indicating parameters of the swapchain creation.

- `surface` is the surface onto which the swapchain will present images. If the creation succeeds, the swapchain becomes associated with `surface`.

- `minImageCount` is the minimum number of presentable images that the application needs. The implementation will either create the swapchain with at least that many images, or it will fail to create the swapchain.

- `imageFormat` is a VkFormat value specifying the format the swapchain image(s) will be created with.

- `imageColorSpace` is a VkColorSpaceKHR value specifying the way the swapchain interprets image data.

- `imageExtent` is the size (in pixels) of the swapchain image(s). The behavior is platform-dependent if the image extent does not match the surface’s `currentExtent` as returned by `vkGetPhysicalDeviceSurfaceCapabilitiesKHR`.

| Note On some platforms, it is normal that `maxImageExtent` may become `(0, 0)`, for example when the window is minimized. In such a case, it is not possible to create a swapchain due to the Valid Usage requirements.

- `imageArrayLayers` is the number of views in a multiview/stereo surface. For non-stereoscopic-3D applications, this value is 1.

- `imageUsage` is a bitmask of VkImageUsageFlagBits describing the intended usage of the (acquired) swapchain images.

- `imageSharingMode` is the sharing mode used for the image(s) of the swapchain.

- `queueFamilyIndexCount` is the number of queue families having access to the image(s) of the swapchain when `imageSharingMode` is `VK_SHARING_MODE_CONCURRENT`.

- `pQueueFamilyIndices` is a pointer to an array of queue family indices having access to the images(s) of the swapchain when `imageSharingMode` is `VK_SHARING_MODE_CONCURRENT`.

- `preTransform` is a VkSurfaceTransformFlagBitsKHR value describing the transform, relative to the presentation engine’s natural orientation, applied to the image content prior to presentation. If it does not match the `currentTransform` value returned by `vkGetPhysicalDeviceSurfaceCapabilitiesKHR`, the presentation engine will transform the image content as part of the presentation operation.

- `compositeAlpha` is a VkCompositeAlphaFlagBitsKHR value indicating the alpha compositing mode to use when this surface is composited together with other surfaces on certain window systems.

- `presentMode` is the presentation mode the swapchain will use. A swapchain’s present mode determines how incoming present requests will be processed and queued internally.

- `clipped` specifies whether the Vulkan implementation is allowed to discard rendering operations that affect regions of the surface that are not visible.

  - If set to `VK_TRUE`, the presentable images associated with the swapchain may not own all of their pixels. Pixels in the presentable images that correspond to regions of the target surface obscured by another window on the desktop, or subject to some other clipping mechanism will have undefined content when read back. Fragment shaders may not execute for these pixels, and thus any side effects they would have had will not occur. `VK_TRUE` value does not guarantee any clipping will occur, but allows more optimal presentation methods to be used on some platforms.

  - If set to `VK_FALSE`, presentable images associated with the swapchain will own all of the pixels they contain.

| Note Applications should set this value to `VK_TRUE` if they do not expect to read back the content of presentable images before presenting them or after reacquiring them, and if their fragment shaders do not have any side effects that require them to run for all pixels in the presentable image.

- `oldSwapchain` is VK_NULL_HANDLE, or the existing non-retired swapchain currently associated with `surface`. Providing a valid `oldSwapchain` may aid in the resource reuse, and also allows the application to still present any images that are already acquired from it.

Upon calling `vkCreateSwapchainKHR` with an `oldSwapchain` that is not VK_NULL_HANDLE, `oldSwapchain` is retired — even if creation of the new swapchain fails. The new swapchain is created in the non-retired state whether or not `oldSwapchain` is VK_NULL_HANDLE.

Upon calling `vkCreateSwapchainKHR` with an `oldSwapchain` that is not VK_NULL_HANDLE, any images from `oldSwapchain` that are not acquired by the application may be freed by the implementation, which may occur even if creation of the new swapchain fails. The application can destroy `oldSwapchain` to free all memory associated with `oldSwapchain`.

| Note Multiple retired swapchains can be associated with the same `VkSurfaceKHR` through multiple uses of `oldSwapchain` that outnumber calls to vkDestroySwapchainKHR. After `oldSwapchain` is retired, the application can pass to vkQueuePresentKHR any images it had already acquired from `oldSwapchain`. E.g., an application may present an image from the old swapchain before an image from the new swapchain is ready to be presented. As usual, vkQueuePresentKHR may fail if `oldSwapchain` has entered a state that causes `VK_ERROR_OUT_OF_DATE_KHR` to be returned. The application can continue to use a shared presentable image obtained from `oldSwapchain` until a presentable image is acquired from the new swapchain, as long as it has not entered a state that causes it to return `VK_ERROR_OUT_OF_DATE_KHR`.

Valid Usage

- `surface` must be a surface that is supported by the device as determined using vkGetPhysicalDeviceSurfaceSupportKHR

- `minImageCount` must be less than or equal to the value returned in the `maxImageCount` member of the `VkSurfaceCapabilitiesKHR` structure returned by `vkGetPhysicalDeviceSurfaceCapabilitiesKHR` for the surface if the returned `maxImageCount` is not zero

- If `presentMode` is not `VK_PRESENT_MODE_SHARED_DEMAND_REFRESH_KHR` nor `VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR`, then `minImageCount` must be greater than or equal to the value returned in the `minImageCount` member of the `VkSurfaceCapabilitiesKHR` structure returned by vkGetPhysicalDeviceSurfaceCapabilitiesKHR for the surface

- `minImageCount` must be `1` if `presentMode` is either `VK_PRESENT_MODE_SHARED_DEMAND_REFRESH_KHR` or `VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR`

- `imageFormat` and `imageColorSpace` must match the `format` and `colorSpace` members, respectively, of one of the `VkSurfaceFormatKHR` structures returned by `vkGetPhysicalDeviceSurfaceFormatsKHR` for the surface

- `imageExtent` must be between `minImageExtent` and `maxImageExtent`, inclusive, where `minImageExtent` and `maxImageExtent` are members of the `VkSurfaceCapabilitiesKHR` structure returned by `vkGetPhysicalDeviceSurfaceCapabilitiesKHR` for the surface

- `imageExtent` members `width` and `height` must both be non-zero

- `imageArrayLayers` must be greater than `0` and less than or equal to the `maxImageArrayLayers` member of the `VkSurfaceCapabilitiesKHR` structure returned by `vkGetPhysicalDeviceSurfaceCapabilitiesKHR` for the surface

- If `presentMode` is `VK_PRESENT_MODE_IMMEDIATE_KHR`, `VK_PRESENT_MODE_MAILBOX_KHR`, `VK_PRESENT_MODE_FIFO_KHR` or `VK_PRESENT_MODE_FIFO_RELAXED_KHR`, `imageUsage` must be a subset of the supported usage flags present in the `supportedUsageFlags` member of the VkSurfaceCapabilitiesKHR structure returned by vkGetPhysicalDeviceSurfaceCapabilitiesKHR for `surface`

- If `presentMode` is `VK_PRESENT_MODE_SHARED_DEMAND_REFRESH_KHR` or `VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR`, `imageUsage` must be a subset of the supported usage flags present in the `sharedPresentSupportedUsageFlags` member of the VkSharedPresentSurfaceCapabilitiesKHR structure returned by vkGetPhysicalDeviceSurfaceCapabilities2KHR for `surface`

- If `imageSharingMode` is `VK_SHARING_MODE_CONCURRENT`, `pQueueFamilyIndices` must be a valid pointer to an array of `queueFamilyIndexCount` `uint32_t` values

- If `imageSharingMode` is `VK_SHARING_MODE_CONCURRENT`, `queueFamilyIndexCount` must be greater than `1`

- If `imageSharingMode` is `VK_SHARING_MODE_CONCURRENT`, each element of `pQueueFamilyIndices` must be unique and must be less than `pQueueFamilyPropertyCount` returned by either vkGetPhysicalDeviceQueueFamilyProperties or vkGetPhysicalDeviceQueueFamilyProperties2 for the `physicalDevice` that was used to create `device`

- `preTransform` must be one of the bits present in the `supportedTransforms` member of the `VkSurfaceCapabilitiesKHR` structure returned by `vkGetPhysicalDeviceSurfaceCapabilitiesKHR` for the surface

- `compositeAlpha` must be one of the bits present in the `supportedCompositeAlpha` member of the `VkSurfaceCapabilitiesKHR` structure returned by `vkGetPhysicalDeviceSurfaceCapabilitiesKHR` for the surface

- `presentMode` must be one of the VkPresentModeKHR values returned by `vkGetPhysicalDeviceSurfacePresentModesKHR` for the surface

- If the logical device was created with VkDeviceGroupDeviceCreateInfo::`physicalDeviceCount` equal to 1, `flags` must not contain `VK_SWAPCHAIN_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT_KHR`

- If `oldSwapchain` is not VK_NULL_HANDLE, `oldSwapchain` must be a non-retired swapchain associated with native window referred to by `surface`

- The implied image creation parameters of the swapchain must be supported as reported by vkGetPhysicalDeviceImageFormatProperties

- If `flags` contains `VK_SWAPCHAIN_CREATE_MUTABLE_FORMAT_BIT_KHR` then the `pNext` chain must include a VkImageFormatListCreateInfo structure with a `viewFormatCount` greater than zero and `pViewFormats` must have an element equal to `imageFormat`

- If `flags` contains `VK_SWAPCHAIN_CREATE_PROTECTED_BIT_KHR`, then `VkSurfaceProtectedCapabilitiesKHR`::`supportsProtected` must be `VK_TRUE` in the VkSurfaceProtectedCapabilitiesKHR structure returned by vkGetPhysicalDeviceSurfaceCapabilities2KHR for `surface`

- If the `pNext` chain includes a VkSurfaceFullScreenExclusiveInfoEXT structure with its `fullScreenExclusive` member set to `VK_FULL_SCREEN_EXCLUSIVE_APPLICATION_CONTROLLED_EXT`, and `surface` was created using vkCreateWin32SurfaceKHR, a VkSurfaceFullScreenExclusiveWin32InfoEXT structure must be included in the `pNext` chain

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SWAPCHAIN_CREATE_INFO_KHR`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkDeviceGroupSwapchainCreateInfoKHR, VkImageFormatListCreateInfo, VkSurfaceFullScreenExclusiveInfoEXT, VkSurfaceFullScreenExclusiveWin32InfoEXT, VkSwapchainCounterCreateInfoEXT, or VkSwapchainDisplayNativeHdrCreateInfoAMD

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be a valid combination of VkSwapchainCreateFlagBitsKHR values

- `surface` must be a valid VkSurfaceKHR handle

- `imageFormat` must be a valid VkFormat value

- `imageColorSpace` must be a valid VkColorSpaceKHR value

- `imageUsage` must be a valid combination of VkImageUsageFlagBits values

- `imageUsage` must not be `0`

- `imageSharingMode` must be a valid VkSharingMode value

- `preTransform` must be a valid VkSurfaceTransformFlagBitsKHR value

- `compositeAlpha` must be a valid VkCompositeAlphaFlagBitsKHR value

- `presentMode` must be a valid VkPresentModeKHR value

- If `oldSwapchain` is not VK_NULL_HANDLE, `oldSwapchain` must be a valid VkSwapchainKHR handle

- If `oldSwapchain` is a valid handle, it must have been created, allocated, or retrieved from `surface`

- Both of `oldSwapchain`, and `surface` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkInstance

Bits which can be set in VkSwapchainCreateInfoKHR::`flags`, specifying parameters of swapchain creation, are:

    typedef enum VkSwapchainCreateFlagBitsKHR {
        VK_SWAPCHAIN_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT_KHR = 0x00000001,
        VK_SWAPCHAIN_CREATE_PROTECTED_BIT_KHR = 0x00000002,
        VK_SWAPCHAIN_CREATE_MUTABLE_FORMAT_BIT_KHR = 0x00000004,
        VK_SWAPCHAIN_CREATE_FLAG_BITS_MAX_ENUM_KHR = 0x7FFFFFFF
    } VkSwapchainCreateFlagBitsKHR;

- `VK_SWAPCHAIN_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT_KHR` specifies that images created from the swapchain (i.e. with the `swapchain` member of VkImageSwapchainCreateInfoKHR set to this swapchain’s handle) must use `VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT`.

- `VK_SWAPCHAIN_CREATE_PROTECTED_BIT_KHR` specifies that images created from the swapchain are protected images.

- `VK_SWAPCHAIN_CREATE_MUTABLE_FORMAT_BIT_KHR` specifies that the images of the swapchain can be used to create a `VkImageView` with a different format than what the swapchain was created with. The list of allowed image view formats are specified by adding a VkImageFormatListCreateInfo structure to the `pNext` chain of `VkSwapchainCreateInfoKHR`. In addition, this flag also specifies that the swapchain can be created with usage flags that are not supported for the format the swapchain is created with but are supported for at least one of the allowed image view formats.

    typedef VkFlags VkSwapchainCreateFlagsKHR;

`VkSwapchainCreateFlagsKHR` is a bitmask type for setting a mask of zero or more VkSwapchainCreateFlagBitsKHR.

If the `pNext` chain of VkSwapchainCreateInfoKHR includes a `VkDeviceGroupSwapchainCreateInfoKHR` structure, then that structure includes a set of device group present modes that the swapchain can be used with.

The `VkDeviceGroupSwapchainCreateInfoKHR` structure is defined as:

    typedef struct VkDeviceGroupSwapchainCreateInfoKHR {
        VkStructureType                     sType;
        const void*                         pNext;
        VkDeviceGroupPresentModeFlagsKHR    modes;
    } VkDeviceGroupSwapchainCreateInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `modes` is a bitfield of modes that the swapchain can be used with.

If this structure is not present, `modes` is considered to be `VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_BIT_KHR`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEVICE_GROUP_SWAPCHAIN_CREATE_INFO_KHR`

- `modes` must be a valid combination of VkDeviceGroupPresentModeFlagBitsKHR values

- `modes` must not be `0`

If the `pNext` chain of VkSwapchainCreateInfoKHR includes a `VkSwapchainDisplayNativeHdrCreateInfoAMD` structure, then that structure includes additional swapchain creation parameters specific to display native HDR support.

The `VkSwapchainDisplayNativeHdrCreateInfoAMD` structure is defined as:

    typedef struct VkSwapchainDisplayNativeHdrCreateInfoAMD {
        VkStructureType    sType;
        const void*        pNext;
        VkBool32           localDimmingEnable;
    } VkSwapchainDisplayNativeHdrCreateInfoAMD;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `localDimmingEnable` specifies whether local dimming is enabled for the swapchain.

If the `pNext` chain of VkSwapchainCreateInfoKHR does not include this structure, the default value for `localDimmingEnable` is `VK_TRUE`, meaning local dimming is initially enabled for the swapchain.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SWAPCHAIN_DISPLAY_NATIVE_HDR_CREATE_INFO_AMD`

Valid Usage

- It is only valid to set `localDimmingEnable` to `VK_TRUE` if VkDisplayNativeHdrSurfaceCapabilitiesAMD::`localDimmingSupport` is supported.

The local dimming HDR setting may also be changed over the life of a swapchain by calling:

    void vkSetLocalDimmingAMD(
        VkDevice                                    device,
        VkSwapchainKHR                              swapChain,
        VkBool32                                    localDimmingEnable);

- `device` is the device associated with `swapChain`.

- `swapChain` handle to enable local dimming.

- `localDimmingEnable` specifies whether local dimming is enabled for the swapchain.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `swapChain` must be a valid VkSwapchainKHR handle

- Both of `device`, and `swapChain` must have been created, allocated, or retrieved from the same VkInstance

Valid Usage

- It is only valid to call vkSetLocalDimmingAMD if VkDisplayNativeHdrSurfaceCapabilitiesAMD::`localDimmingSupport` is supported.

If the `pNext` chain of VkSwapchainCreateInfoKHR includes a VkSurfaceFullScreenExclusiveInfoEXT structure, then that structure specifies the application’s preferred full-screen presentation behavior. If this structure is not present, `fullScreenExclusive` is considered to be `VK_FULL_SCREEN_EXCLUSIVE_DEFAULT_EXT`.

To enable surface counters when creating a swapchain, add a `VkSwapchainCounterCreateInfoEXT` structure to the `pNext` chain of VkSwapchainCreateInfoKHR. `VkSwapchainCounterCreateInfoEXT` is defined as:

    typedef struct VkSwapchainCounterCreateInfoEXT {
        VkStructureType             sType;
        const void*                 pNext;
        VkSurfaceCounterFlagsEXT    surfaceCounters;
    } VkSwapchainCounterCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `surfaceCounters` is a bitmask of VkSurfaceCounterFlagBitsEXT specifying surface counters to enable for the swapchain.

Valid Usage

- The bits in `surfaceCounters` must be supported by VkSwapchainCreateInfoKHR::`surface`, as reported by vkGetPhysicalDeviceSurfaceCapabilities2EXT.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SWAPCHAIN_COUNTER_CREATE_INFO_EXT`

- `surfaceCounters` must be a valid combination of VkSurfaceCounterFlagBitsEXT values

The requested counters become active when the first presentation command for the associated swapchain is processed by the presentation engine. To query the value of an active counter, use:

    VkResult vkGetSwapchainCounterEXT(
        VkDevice                                    device,
        VkSwapchainKHR                              swapchain,
        VkSurfaceCounterFlagBitsEXT                 counter,
        uint64_t*                                   pCounterValue);

- `device` is the VkDevice associated with `swapchain`.

- `swapchain` is the swapchain from which to query the counter value.

- `counter` is the counter to query.

- `pCounterValue` will return the current value of the counter.

If a counter is not available because the swapchain is out of date, the implementation may return `VK_ERROR_OUT_OF_DATE_KHR`.

Valid Usage

- One or more present commands on `swapchain` must have been processed by the presentation engine.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `swapchain` must be a valid VkSwapchainKHR handle

- `counter` must be a valid VkSurfaceCounterFlagBitsEXT value

- `pCounterValue` must be a valid pointer to a `uint64_t` value

- Both of `device`, and `swapchain` must have been created, allocated, or retrieved from the same VkInstance

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_DEVICE_LOST`

  - `VK_ERROR_OUT_OF_DATE_KHR`

As mentioned above, if `vkCreateSwapchainKHR` succeeds, it will return a handle to a swapchain containing an array of at least `minImageCount` presentable images.

While acquired by the application, presentable images can be used in any way that equivalent non-presentable images can be used. A presentable image is equivalent to a non-presentable image created with the following `VkImageCreateInfo` parameters:

`VkImageCreateInfo` Field | Value
--- | ---
`flags` | `VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT` is set if `VK_SWAPCHAIN_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT_KHR` is set `VK_IMAGE_CREATE_PROTECTED_BIT` is set if `VK_SWAPCHAIN_CREATE_PROTECTED_BIT_KHR` is set `VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT` and `VK_IMAGE_CREATE_EXTENDED_USAGE_BIT_KHR` are both set if `VK_SWAPCHAIN_CREATE_MUTABLE_FORMAT_BIT_KHR` is set all other bits are unset
`imageType` | `VK_IMAGE_TYPE_2D`
`format` | `pCreateInfo->imageFormat`
`extent` | {`pCreateInfo->imageExtent.width`, `pCreateInfo->imageExtent.height`, `1`}
`mipLevels` | 1
`arrayLayers` | `pCreateInfo->imageArrayLayers`
`samples` | `VK_SAMPLE_COUNT_1_BIT`
`tiling` | `VK_IMAGE_TILING_OPTIMAL`
`usage` | `pCreateInfo->imageUsage`
`sharingMode` | `pCreateInfo->imageSharingMode`
`queueFamilyIndexCount` | `pCreateInfo->queueFamilyIndexCount`
`pQueueFamilyIndices` | `pCreateInfo->pQueueFamilyIndices`
`initialLayout` | `VK_IMAGE_LAYOUT_UNDEFINED`

The `surface` must not be destroyed until after the swapchain is destroyed.

If `oldSwapchain` is VK_NULL_HANDLE, and the native window referred to by `surface` is already associated with a Vulkan swapchain, `VK_ERROR_NATIVE_WINDOW_IN_USE_KHR` must be returned.

If the native window referred to by `surface` is already associated with a non-Vulkan graphics API surface, `VK_ERROR_NATIVE_WINDOW_IN_USE_KHR` must be returned.

The native window referred to by `surface` must not become associated with a non-Vulkan graphics API surface before all associated Vulkan swapchains have been destroyed.

Like core functions, several WSI functions, including `vkCreateSwapchainKHR` return `VK_ERROR_DEVICE_LOST` if the logical device was lost. See Lost Device. As with most core objects, `VkSwapchainKHR` is a child of the device and is affected by the lost state; it must be destroyed before destroying the `VkDevice`. However, `VkSurfaceKHR` is not a child of any `VkDevice` and is not otherwise affected by the lost device. After successfully recreating a `VkDevice`, the same `VkSurfaceKHR` can be used to create a new `VkSwapchainKHR`, provided the previous one was destroyed.

| Note As mentioned in Lost Device, after a lost device event, the `VkPhysicalDevice` may also be lost. If other `VkPhysicalDevice` are available, they can be used together with the same `VkSurfaceKHR` to create the new `VkSwapchainKHR`, however the application must query the surface capabilities again, because they may differ on a per-physical device basis.

To destroy a swapchain object call:

    void vkDestroySwapchainKHR(
        VkDevice                                    device,
        VkSwapchainKHR                              swapchain,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the VkDevice associated with `swapchain`.

- `swapchain` is the swapchain to destroy.

- `pAllocator` is the allocator used for host memory allocated for the swapchain object when there is no more specific allocator available (see Memory Allocation).

The application must not destroy a swapchain until after completion of all outstanding operations on images that were acquired from the swapchain. `swapchain` and all associated `VkImage` handles are destroyed, and must not be acquired or used any more by the application. The memory of each `VkImage` will only be freed after that image is no longer used by the presentation engine. For example, if one image of the swapchain is being displayed in a window, the memory for that image may not be freed until the window is destroyed, or another swapchain is created for the window. Destroying the swapchain does not invalidate the parent `VkSurfaceKHR`, and a new swapchain can be created with it.

When a swapchain associated with a display surface is destroyed, if the image most recently presented to the display surface is from the swapchain being destroyed, then either any display resources modified by presenting images from any swapchain associated with the display surface must be reverted by the implementation to their state prior to the first present performed on one of these swapchains, or such resources must be left in their current state.

If `swapchain` has exclusive full-screen access, it is released before the swapchain is destroyed.

Valid Usage

- All uses of presentable images acquired from `swapchain` must have completed execution

- If `VkAllocationCallbacks` were provided when `swapchain` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `swapchain` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `swapchain` is not VK_NULL_HANDLE, `swapchain` must be a valid VkSwapchainKHR handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- Both of `device`, and `swapchain` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkInstance

Host Synchronization

- Host access to `swapchain` must be externally synchronized

When the `VK_KHR_display_swapchain` extension is enabled, multiple swapchains that share presentable images are created by calling:

    VkResult vkCreateSharedSwapchainsKHR(
        VkDevice                                    device,
        uint32_t                                    swapchainCount,
        const VkSwapchainCreateInfoKHR*             pCreateInfos,
        const VkAllocationCallbacks*                pAllocator,
        VkSwapchainKHR*                             pSwapchains);

- `device` is the device to create the swapchains for.

- `swapchainCount` is the number of swapchains to create.

- `pCreateInfos` is a pointer to an array of VkSwapchainCreateInfoKHR structures specifying the parameters of the created swapchains.

- `pAllocator` is the allocator used for host memory allocated for the swapchain objects when there is no more specific allocator available (see Memory Allocation).

- `pSwapchains` is a pointer to an array of VkSwapchainKHR handles in which the created swapchain objects will be returned.

`vkCreateSharedSwapchainsKHR` is similar to vkCreateSwapchainKHR, except that it takes an array of VkSwapchainCreateInfoKHR structures, and returns an array of swapchain objects.

The swapchain creation parameters that affect the properties and number of presentable images must match between all the swapchains. If the displays used by any of the swapchains do not use the same presentable image layout or are incompatible in a way that prevents sharing images, swapchain creation will fail with the result code `VK_ERROR_INCOMPATIBLE_DISPLAY_KHR`. If any error occurs, no swapchains will be created. Images presented to multiple swapchains must be re-acquired from all of them before transitioning away from `VK_IMAGE_LAYOUT_PRESENT_SRC_KHR`. After destroying one or more of the swapchains, the remaining swapchains and the presentable images can continue to be used.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pCreateInfos` must be a valid pointer to an array of `swapchainCount` valid VkSwapchainCreateInfoKHR structures

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pSwapchains` must be a valid pointer to an array of `swapchainCount` VkSwapchainKHR handles

- `swapchainCount` must be greater than `0`

Host Synchronization

- Host access to `pCreateInfos`[].surface must be externally synchronized

- Host access to `pCreateInfos`[].oldSwapchain must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_INCOMPATIBLE_DISPLAY_KHR`

  - `VK_ERROR_DEVICE_LOST`

  - `VK_ERROR_SURFACE_LOST_KHR`

To obtain the array of presentable images associated with a swapchain, call:

    VkResult vkGetSwapchainImagesKHR(
        VkDevice                                    device,
        VkSwapchainKHR                              swapchain,
        uint32_t*                                   pSwapchainImageCount,
        VkImage*                                    pSwapchainImages);

- `device` is the device associated with `swapchain`.

- `swapchain` is the swapchain to query.

- `pSwapchainImageCount` is a pointer to an integer related to the number of presentable images available or queried, as described below.

- `pSwapchainImages` is either `NULL` or a pointer to an array of `VkImage` handles.

If `pSwapchainImages` is `NULL`, then the number of presentable images for `swapchain` is returned in `pSwapchainImageCount`. Otherwise, `pSwapchainImageCount` must point to a variable set by the user to the number of elements in the `pSwapchainImages` array, and on return the variable is overwritten with the number of structures actually written to `pSwapchainImages`. If the value of `pSwapchainImageCount` is less than the number of presentable images for `swapchain`, at most `pSwapchainImageCount` structures will be written. If `pSwapchainImageCount` is smaller than the number of presentable images for `swapchain`, `VK_INCOMPLETE` will be returned instead of `VK_SUCCESS` to indicate that not all the available values were returned.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `swapchain` must be a valid VkSwapchainKHR handle

- `pSwapchainImageCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pSwapchainImageCount` is not `0`, and `pSwapchainImages` is not `NULL`, `pSwapchainImages` must be a valid pointer to an array of `pSwapchainImageCount` VkImage handles

- Both of `device`, and `swapchain` must have been created, allocated, or retrieved from the same VkInstance

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

| Note By knowing all presentable images used in the swapchain, the application can create command buffers that reference these images prior to entering its main rendering loop.

Images returned by vkGetSwapchainImagesKHR are fully backed by memory before they are passed to the application. All presentable images are initially in the `VK_IMAGE_LAYOUT_UNDEFINED` layout, thus before using presentable images, the application must transition them to a valid layout for the intended use.

Further, the lifetime of presentable images is controlled by the implementation, so applications must not destroy a presentable image. See vkDestroySwapchainKHR for further details on the lifetime of presentable images.

Images can also be created by using vkCreateImage with VkImageSwapchainCreateInfoKHR and bound to swapchain memory using vkBindImageMemory2KHR with VkBindImageMemorySwapchainInfoKHR. These images can be used anywhere swapchain images are used, and are useful in logical devices with multiple physical devices to create peer memory bindings of swapchain memory. These images and bindings have no effect on what memory is presented. Unlike images retrieved from `vkGetSwapchainImagesKHR`, these images must be destroyed with vkDestroyImage.

To acquire an available presentable image to use, and retrieve the index of that image, call:

    VkResult vkAcquireNextImageKHR(
        VkDevice                                    device,
        VkSwapchainKHR                              swapchain,
        uint64_t                                    timeout,
        VkSemaphore                                 semaphore,
        VkFence                                     fence,
        uint32_t*                                   pImageIndex);

- `device` is the device associated with `swapchain`.

- `swapchain` is the non-retired swapchain from which an image is being acquired.

- `timeout` specifies how long the function waits, in nanoseconds, if no image is available.

- `semaphore` is VK_NULL_HANDLE or a semaphore to signal.

- `fence` is VK_NULL_HANDLE or a fence to signal.

- `pImageIndex` is a pointer to a `uint32_t` in which the index of the next image to use (i.e. an index into the array of images returned by `vkGetSwapchainImagesKHR`) is returned.

Valid Usage

- `swapchain` must not be in the retired state

- If `semaphore` is not VK_NULL_HANDLE it must be unsignaled

- If `semaphore` is not VK_NULL_HANDLE it must not have any uncompleted signal or wait operations pending

- If `fence` is not VK_NULL_HANDLE it must be unsignaled and must not be associated with any other queue command that has not yet completed execution on that queue

- `semaphore` and `fence` must not both be equal to VK_NULL_HANDLE

- If the number of currently acquired images is greater than the difference between the number of images in `swapchain` and the value of VkSurfaceCapabilitiesKHR::`minImageCount` as returned by a call to vkGetPhysicalDeviceSurfaceCapabilities2KHR with the `surface` used to create `swapchain`, `timeout` must not be `UINT64_MAX`

- `semaphore` must have a VkSemaphoreType of `VK_SEMAPHORE_TYPE_BINARY`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `swapchain` must be a valid VkSwapchainKHR handle

- If `semaphore` is not VK_NULL_HANDLE, `semaphore` must be a valid VkSemaphore handle

- If `fence` is not VK_NULL_HANDLE, `fence` must be a valid VkFence handle

- `pImageIndex` must be a valid pointer to a `uint32_t` value

- If `semaphore` is a valid handle, it must have been created, allocated, or retrieved from `device`

- If `fence` is a valid handle, it must have been created, allocated, or retrieved from `device`

- Both of `device`, and `swapchain` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkInstance

Host Synchronization

- Host access to `swapchain` must be externally synchronized

- Host access to `semaphore` must be externally synchronized

- Host access to `fence` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_TIMEOUT`

  - `VK_NOT_READY`

  - `VK_SUBOPTIMAL_KHR`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_DEVICE_LOST`

  - `VK_ERROR_OUT_OF_DATE_KHR`

  - `VK_ERROR_SURFACE_LOST_KHR`

  - `VK_ERROR_FULL_SCREEN_EXCLUSIVE_MODE_LOST_EXT`

When successful, `vkAcquireNextImageKHR` acquires a presentable image from `swapchain` that an application can use, and sets `pImageIndex` to the index of that image within the swapchain. The presentation engine may not have finished reading from the image at the time it is acquired, so the application must use `semaphore` and/or `fence` to ensure that the image layout and contents are not modified until the presentation engine reads have completed. If `semaphore` is not VK_NULL_HANDLE, the application may assume that, once `vkAcquireNextImageKHR` returns, the semaphore signal operation referenced by `semaphore` has been submitted for execution. The order in which images are acquired is implementation-dependent, and may be different than the order the images were presented.

If `timeout` is zero, then `vkAcquireNextImageKHR` does not wait, and will either successfully acquire an image, or fail and return `VK_NOT_READY` if no image is available.

If the specified timeout period expires before an image is acquired, `vkAcquireNextImageKHR` returns `VK_TIMEOUT`. If `timeout` is `UINT64_MAX`, the timeout period is treated as infinite, and `vkAcquireNextImageKHR` will block until an image is acquired or an error occurs.

An image will eventually be acquired if the number of images that the application has currently acquired (but not yet presented) is less than or equal to the difference between the number of images in `swapchain` and the value of VkSurfaceCapabilitiesKHR::`minImageCount`. If the number of currently acquired images is greater than this, `vkAcquireNextImageKHR` should not be called; if it is, `timeout` must not be `UINT64_MAX`.

If an image is acquired successfully, `vkAcquireNextImageKHR` must either return `VK_SUCCESS`, or `VK_SUBOPTIMAL_KHR` if the swapchain no longer matches the surface properties exactly, but can still be used for presentation.

| Note This may happen, for example, if the platform surface has been resized but the platform is able to scale the presented images to the new size to produce valid surface updates. It is up to the application to decide whether it prefers to continue using the current swapchain in this state, or to re-create the swapchain to better match the platform surface properties.

If the swapchain images no longer match native surface properties, either `VK_SUBOPTIMAL_KHR` or `VK_ERROR_OUT_OF_DATE_KHR` must be returned. If `VK_ERROR_OUT_OF_DATE_KHR` is returned, no image is acquired and attempts to present previously acquired images to the swapchain will also fail with `VK_ERROR_OUT_OF_DATE_KHR`. Applications need to create a new swapchain for the surface to continue presenting if `VK_ERROR_OUT_OF_DATE_KHR` is returned.

If device loss occurs (see Lost Device) before the timeout has expired, `vkAcquireNextImageKHR` must return in finite time with either one of the allowed success codes, or `VK_ERROR_DEVICE_LOST`.

If `semaphore` is not VK_NULL_HANDLE, the semaphore must be unsignaled, with no signal or wait operations pending. It will become signaled when the application can use the image.

| Note Use of `semaphore` allows rendering operations to be recorded and submitted before the presentation engine has completed its use of the image.

If `fence` is not equal to VK_NULL_HANDLE, the fence must be unsignaled, with no signal operations pending. It will become signaled when the application can use the image.

| Note Applications should not rely on `vkAcquireNextImageKHR` blocking in order to meter their rendering speed. The implementation may return from this function immediately regardless of how many presentation requests are queued, and regardless of when queued presentation requests will complete relative to the call. Instead, applications can use `fence` to meter their frame generation work to match the presentation rate.

An application must wait until either the `semaphore` or `fence` is signaled before accessing the image’s data.

| Note When the presentable image will be accessed by some stage S, the recommended idiom for ensuring correct synchronization is: The VkSubmitInfo used to submit the image layout transition for execution includes `vkAcquireNextImageKHR`::`semaphore` in its `pWaitSemaphores` member, with the corresponding element of `pWaitDstStageMask` including S. The synchronization command that performs any necessary image layout transition includes S in both the `srcStageMask` and `dstStageMask`.

After a successful return, the image indicated by `pImageIndex` and its data will be unmodified compared to when it was presented.

| Note Exclusive ownership of presentable images corresponding to a swapchain created with `VK_SHARING_MODE_EXCLUSIVE` as defined in Resource Sharing is not altered by a call to `vkAcquireNextImageKHR`. That means upon the first acquisition from such a swapchain presentable images are not owned by any queue family, while at subsequent acquisitions the presentable images remain owned by the queue family the image was previously presented on.

The possible return values for `vkAcquireNextImageKHR` depend on the `timeout` provided:

- `VK_SUCCESS` is returned if an image became available.

- `VK_ERROR_SURFACE_LOST_KHR` if the surface becomes no longer available.

- `VK_NOT_READY` is returned if `timeout` is zero and no image was available.

- `VK_TIMEOUT` is returned if `timeout` is greater than zero and less than `UINT64_MAX`, and no image became available within the time allowed.

- `VK_SUBOPTIMAL_KHR` is returned if an image became available, and the swapchain no longer matches the surface properties exactly, but can still be used to present to the surface successfully.

| Note This may happen, for example, if the platform surface has been resized but the platform is able to scale the presented images to the new size to produce valid surface updates. It is up to the application to decide whether it prefers to continue using the current swapchain indefinitely or temporarily in this state, or to re-create the swapchain to better match the platform surface properties.

- `VK_ERROR_OUT_OF_DATE_KHR` is returned if the surface has changed in such a way that it is no longer compatible with the swapchain, and further presentation requests using the swapchain will fail. Applications must query the new surface properties and recreate their swapchain if they wish to continue presenting to the surface.

If the native surface and presented image sizes no longer match, presentation may fail. If presentation does succeed, the mapping from the presented image to the native surface is implementation-defined. It is the application’s responsibility to detect surface size changes and react appropriately. If presentation fails because of a mismatch in the surface and presented image sizes, a `VK_ERROR_OUT_OF_DATE_KHR` error will be returned.

| Note For example, consider a 4x3 window/surface that gets resized to be 3x4 (taller than wider). On some window systems, the portion of the window/surface that was previously and still is visible (the 3x3 part) will contain the same contents as before, while the remaining parts of the window will have undefined contents. Other window systems may squash/stretch the image to fill the new window size without any undefined contents, or apply some other mapping.

To acquire an available presentable image to use, and retrieve the index of that image, call:

    VkResult vkAcquireNextImage2KHR(
        VkDevice                                    device,
        const VkAcquireNextImageInfoKHR*            pAcquireInfo,
        uint32_t*                                   pImageIndex);

- `device` is the device associated with `swapchain`.

- `pAcquireInfo` is a pointer to a VkAcquireNextImageInfoKHR structure containing parameters of the acquire.

- `pImageIndex` is a pointer to a `uint32_t` that is set to the index of the next image to use.

Valid Usage

- If the number of currently acquired images is greater than the difference between the number of images in the `swapchain` member of `pAcquireInfo` and the value of VkSurfaceCapabilitiesKHR::`minImageCount` as returned by a call to vkGetPhysicalDeviceSurfaceCapabilities2KHR with the `surface` used to create `swapchain`, the `timeout` member of `pAcquireInfo` must not be `UINT64_MAX`

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pAcquireInfo` must be a valid pointer to a valid VkAcquireNextImageInfoKHR structure

- `pImageIndex` must be a valid pointer to a `uint32_t` value

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_TIMEOUT`

  - `VK_NOT_READY`

  - `VK_SUBOPTIMAL_KHR`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_DEVICE_LOST`

  - `VK_ERROR_OUT_OF_DATE_KHR`

  - `VK_ERROR_SURFACE_LOST_KHR`

  - `VK_ERROR_FULL_SCREEN_EXCLUSIVE_MODE_LOST_EXT`

The `VkAcquireNextImageInfoKHR` structure is defined as:

    typedef struct VkAcquireNextImageInfoKHR {
        VkStructureType    sType;
        const void*        pNext;
        VkSwapchainKHR     swapchain;
        uint64_t           timeout;
        VkSemaphore        semaphore;
        VkFence            fence;
        uint32_t           deviceMask;
    } VkAcquireNextImageInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `swapchain` is a non-retired swapchain from which an image is acquired.

- `timeout` specifies how long the function waits, in nanoseconds, if no image is available.

- `semaphore` is VK_NULL_HANDLE or a semaphore to signal.

- `fence` is VK_NULL_HANDLE or a fence to signal.

- `deviceMask` is a mask of physical devices for which the swapchain image will be ready to use when the semaphore or fence is signaled.

If vkAcquireNextImageKHR is used, the device mask is considered to include all physical devices in the logical device.

| Note vkAcquireNextImage2KHR signals at most one semaphore, even if the application requests waiting for multiple physical devices to be ready via the `deviceMask`. However, only a single physical device can wait on that semaphore, since the semaphore becomes unsignaled when the wait succeeds. For other physical devices to wait for the image to be ready, it is necessary for the application to submit semaphore signal operation(s) to that first physical device to signal additional semaphore(s) after the wait succeeds, which the other physical device(s) can wait upon.

Valid Usage

- `swapchain` must not be in the retired state

- If `semaphore` is not VK_NULL_HANDLE it must be unsignaled

- If `semaphore` is not VK_NULL_HANDLE it must not have any uncompleted signal or wait operations pending

- If `fence` is not VK_NULL_HANDLE it must be unsignaled and must not be associated with any other queue command that has not yet completed execution on that queue

- `semaphore` and `fence` must not both be equal to VK_NULL_HANDLE

- `deviceMask` must be a valid device mask

- `deviceMask` must not be zero

- `semaphore` must have a VkSemaphoreType of `VK_SEMAPHORE_TYPE_BINARY`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_ACQUIRE_NEXT_IMAGE_INFO_KHR`

- `pNext` must be `NULL`

- `swapchain` must be a valid VkSwapchainKHR handle

- If `semaphore` is not VK_NULL_HANDLE, `semaphore` must be a valid VkSemaphore handle

- If `fence` is not VK_NULL_HANDLE, `fence` must be a valid VkFence handle

- Each of `fence`, `semaphore`, and `swapchain` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkInstance

Host Synchronization

- Host access to `swapchain` must be externally synchronized

- Host access to `semaphore` must be externally synchronized

- Host access to `fence` must be externally synchronized

After queueing all rendering commands and transitioning the image to the correct layout, to queue an image for presentation, call:

    VkResult vkQueuePresentKHR(
        VkQueue                                     queue,
        const VkPresentInfoKHR*                     pPresentInfo);

- `queue` is a queue that is capable of presentation to the target surface’s platform on the same device as the image’s swapchain.

- `pPresentInfo` is a pointer to a VkPresentInfoKHR structure specifying parameters of the presentation.

| Note There is no requirement for an application to present images in the same order that they were acquired - applications can arbitrarily present any image that is currently acquired.

Valid Usage

- Each element of `pSwapchains` member of `pPresentInfo` must be a swapchain that is created for a surface for which presentation is supported from `queue` as determined using a call to `vkGetPhysicalDeviceSurfaceSupportKHR`

- If more than one member of `pSwapchains` was created from a display surface, all display surfaces referenced that refer to the same display must use the same display mode

- When a semaphore wait operation referring to a binary semaphore defined by the elements of the `pWaitSemaphores` member of `pPresentInfo` executes on `queue`, there must be no other queues waiting on the same semaphore.

- All elements of the `pWaitSemaphores` member of `pPresentInfo` must be semaphores that are signaled, or have semaphore signal operations previously submitted for execution.

- All elements of the `pWaitSemaphores` member of `pPresentInfo` must be created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_BINARY`.

- All elements of the `pWaitSemaphores` member of `pPresentInfo` must reference a semaphore signal operation that has been submitted for execution and any semaphore signal operations on which it depends (if any) must have also been submitted for execution.

Any writes to memory backing the images referenced by the `pImageIndices` and `pSwapchains` members of `pPresentInfo`, that are available before vkQueuePresentKHR is executed, are automatically made visible to the read access performed by the presentation engine. This automatic visibility operation for an image happens-after the semaphore signal operation, and happens-before the presentation engine accesses the image.

Queueing an image for presentation defines a set of queue operations, including waiting on the semaphores and submitting a presentation request to the presentation engine. However, the scope of this set of queue operations does not include the actual processing of the image by the presentation engine.

If `vkQueuePresentKHR` fails to enqueue the corresponding set of queue operations, it may return `VK_ERROR_OUT_OF_HOST_MEMORY` or `VK_ERROR_OUT_OF_DEVICE_MEMORY`. If it does, the implementation must ensure that the state and contents of any resources or synchronization primitives referenced is unaffected by the call or its failure.

If `vkQueuePresentKHR` fails in such a way that the implementation is unable to make that guarantee, the implementation must return `VK_ERROR_DEVICE_LOST`.

However, if the presentation request is rejected by the presentation engine with an error `VK_ERROR_OUT_OF_DATE_KHR` or `VK_ERROR_SURFACE_LOST_KHR`, the set of queue operations are still considered to be enqueued and thus any semaphore wait operation specified in VkPresentInfoKHR will execute when the corresponding queue operation is complete.

If any `swapchain` member of `pPresentInfo` was created with `VK_FULL_SCREEN_EXCLUSIVE_APPLICATION_CONTROLLED_EXT`, `VK_ERROR_FULL_SCREEN_EXCLUSIVE_MODE_LOST_EXT` will be returned if that swapchain does not have exclusive full-screen access, possibly for implementation-specific reasons outside of the application’s control.

Valid Usage (Implicit)

- `queue` must be a valid VkQueue handle

- `pPresentInfo` must be a valid pointer to a valid VkPresentInfoKHR structure

Host Synchronization

- Host access to `queue` must be externally synchronized

- Host access to `pPresentInfo.pWaitSemaphores`[] must be externally synchronized

- Host access to `pPresentInfo.pSwapchains`[] must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
- | - | Any | -

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_SUBOPTIMAL_KHR`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_DEVICE_LOST`

  - `VK_ERROR_OUT_OF_DATE_KHR`

  - `VK_ERROR_SURFACE_LOST_KHR`

  - `VK_ERROR_FULL_SCREEN_EXCLUSIVE_MODE_LOST_EXT`

The `VkPresentInfoKHR` structure is defined as:

    typedef struct VkPresentInfoKHR {
        VkStructureType          sType;
        const void*              pNext;
        uint32_t                 waitSemaphoreCount;
        const VkSemaphore*       pWaitSemaphores;
        uint32_t                 swapchainCount;
        const VkSwapchainKHR*    pSwapchains;
        const uint32_t*          pImageIndices;
        VkResult*                pResults;
    } VkPresentInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `waitSemaphoreCount` is the number of semaphores to wait for before issuing the present request. The number may be zero.

- `pWaitSemaphores` is `NULL` or a pointer to an array of VkSemaphore objects with `waitSemaphoreCount` entries, and specifies the semaphores to wait for before issuing the present request.

- `swapchainCount` is the number of swapchains being presented to by this command.

- `pSwapchains` is a pointer to an array of VkSwapchainKHR objects with `swapchainCount` entries. A given swapchain must not appear in this list more than once.

- `pImageIndices` is a pointer to an array of indices into the array of each swapchain’s presentable images, with `swapchainCount` entries. Each entry in this array identifies the image to present on the corresponding entry in the `pSwapchains` array.

- `pResults` is a pointer to an array of VkResult typed elements with `swapchainCount` entries. Applications that do not need per-swapchain results can use `NULL` for `pResults`. If non-`NULL`, each entry in `pResults` will be set to the VkResult for presenting the swapchain corresponding to the same index in `pSwapchains`.

Before an application can present an image, the image’s layout must be transitioned to the `VK_IMAGE_LAYOUT_PRESENT_SRC_KHR` layout, or for a shared presentable image the `VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR` layout.

| Note When transitioning the image to `VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR` or `VK_IMAGE_LAYOUT_PRESENT_SRC_KHR`, there is no need to delay subsequent processing, or perform any visibility operations (as vkQueuePresentKHR performs automatic visibility operations). To achieve this, the `dstAccessMask` member of the VkImageMemoryBarrier should be set to `0`, and the `dstStageMask` parameter should be set to `VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT`.

Valid Usage

- Each element of `pImageIndices` must be the index of a presentable image acquired from the swapchain specified by the corresponding element of the `pSwapchains` array, and the presented image subresource must be in the `VK_IMAGE_LAYOUT_PRESENT_SRC_KHR` or `VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR` layout at the time the operation is executed on a `VkDevice`

- All elements of the `pWaitSemaphores` must have a VkSemaphoreType of `VK_SEMAPHORE_TYPE_BINARY`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PRESENT_INFO_KHR`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkDeviceGroupPresentInfoKHR, VkDisplayPresentInfoKHR, VkPresentFrameTokenGGP, VkPresentRegionsKHR, or VkPresentTimesInfoGOOGLE

- The `sType` value of each struct in the `pNext` chain must be unique

- If `waitSemaphoreCount` is not `0`, `pWaitSemaphores` must be a valid pointer to an array of `waitSemaphoreCount` valid VkSemaphore handles

- `pSwapchains` must be a valid pointer to an array of `swapchainCount` valid VkSwapchainKHR handles

- `pImageIndices` must be a valid pointer to an array of `swapchainCount` `uint32_t` values

- If `pResults` is not `NULL`, `pResults` must be a valid pointer to an array of `swapchainCount` VkResult values

- `swapchainCount` must be greater than `0`

- Both of the elements of `pSwapchains`, and the elements of `pWaitSemaphores` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkInstance

When the `VK_KHR_incremental_present` extension is enabled, additional fields can be specified that allow an application to specify that only certain rectangular regions of the presentable images of a swapchain are changed. This is an optimization hint that a presentation engine may use to only update the region of a surface that is actually changing. The application still must ensure that all pixels of a presented image contain the desired values, in case the presentation engine ignores this hint. An application can provide this hint by adding a `VkPresentRegionsKHR` structure to the `pNext` chain of the `VkPresentInfoKHR` structure.

The `VkPresentRegionsKHR` structure is defined as:

    typedef struct VkPresentRegionsKHR {
        VkStructureType              sType;
        const void*                  pNext;
        uint32_t                     swapchainCount;
        const VkPresentRegionKHR*    pRegions;
    } VkPresentRegionsKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `swapchainCount` is the number of swapchains being presented to by this command.

- `pRegions` is `NULL` or a pointer to an array of `VkPresentRegionKHR` elements with `swapchainCount` entries. If not `NULL`, each element of `pRegions` contains the region that has changed since the last present to the swapchain in the corresponding entry in the `VkPresentInfoKHR`::`pSwapchains` array.

Valid Usage

- `swapchainCount` must be the same value as `VkPresentInfoKHR`::`swapchainCount`, where `VkPresentInfoKHR` is included in the `pNext` chain of this `VkPresentRegionsKHR` structure

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PRESENT_REGIONS_KHR`

- If `pRegions` is not `NULL`, `pRegions` must be a valid pointer to an array of `swapchainCount` valid VkPresentRegionKHR structures

- `swapchainCount` must be greater than `0`

For a given image and swapchain, the region to present is specified by the `VkPresentRegionKHR` structure, which is defined as:

    typedef struct VkPresentRegionKHR {
        uint32_t                 rectangleCount;
        const VkRectLayerKHR*    pRectangles;
    } VkPresentRegionKHR;

- `rectangleCount` is the number of rectangles in `pRectangles`, or zero if the entire image has changed and should be presented.

- `pRectangles` is either `NULL` or a pointer to an array of `VkRectLayerKHR` structures. The `VkRectLayerKHR` structure is the framebuffer coordinates, plus layer, of a portion of a presentable image that has changed and must be presented. If non-`NULL`, each entry in `pRectangles` is a rectangle of the given image that has changed since the last image was presented to the given swapchain.

Valid Usage (Implicit)

- If `rectangleCount` is not `0`, and `pRectangles` is not `NULL`, `pRectangles` must be a valid pointer to an array of `rectangleCount` valid VkRectLayerKHR structures

The `VkRectLayerKHR` structure is defined as:

    typedef struct VkRectLayerKHR {
        VkOffset2D    offset;
        VkExtent2D    extent;
        uint32_t      layer;
    } VkRectLayerKHR;

- `offset` is the origin of the rectangle, in pixels.

- `extent` is the size of the rectangle, in pixels.

- `layer` is the layer of the image. For images with only one layer, the value of `layer` must be 0.

Valid Usage

- The sum of `offset` and `extent` must be no greater than the `imageExtent` member of the `VkSwapchainCreateInfoKHR` structure given to vkCreateSwapchainKHR.

- `layer` must be less than `imageArrayLayers` member of the `VkSwapchainCreateInfoKHR` structure given to vkCreateSwapchainKHR.

Some platforms allow the size of a surface to change, and then scale the pixels of the image to fit the surface. `VkRectLayerKHR` specifies pixels of the swapchain’s image(s), which will be constant for the life of the swapchain.

When the `VK_KHR_display_swapchain` extension is enabled additional fields can be specified when presenting an image to a swapchain by setting VkPresentInfoKHR::`pNext` to point to a VkDisplayPresentInfoKHR structure.

The `VkDisplayPresentInfoKHR` structure is defined as:

    typedef struct VkDisplayPresentInfoKHR {
        VkStructureType    sType;
        const void*        pNext;
        VkRect2D           srcRect;
        VkRect2D           dstRect;
        VkBool32           persistent;
    } VkDisplayPresentInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `srcRect` is a rectangular region of pixels to present. It must be a subset of the image being presented. If `VkDisplayPresentInfoKHR` is not specified, this region will be assumed to be the entire presentable image.

- `dstRect` is a rectangular region within the visible region of the swapchain’s display mode. If `VkDisplayPresentInfoKHR` is not specified, this region will be assumed to be the entire visible region of the visible region of the swapchain’s mode. If the specified rectangle is a subset of the display mode’s visible region, content from display planes below the swapchain’s plane will be visible outside the rectangle. If there are no planes below the swapchain’s, the area outside the specified rectangle will be black. If portions of the specified rectangle are outside of the display’s visible region, pixels mapping only to those portions of the rectangle will be discarded.

- `persistent`: If this is `VK_TRUE`, the display engine will enable buffered mode on displays that support it. This allows the display engine to stop sending content to the display until a new image is presented. The display will instead maintain a copy of the last presented image. This allows less power to be used, but may increase presentation latency. If `VkDisplayPresentInfoKHR` is not specified, persistent mode will not be used.

If the extent of the `srcRect` and `dstRect` are not equal, the presented pixels will be scaled accordingly.

Valid Usage

- `srcRect` must specify a rectangular region that is a subset of the image being presented

- `dstRect` must specify a rectangular region that is a subset of the `visibleRegion` parameter of the display mode the swapchain being presented uses

- If the `persistentContent` member of the `VkDisplayPropertiesKHR` structure returned by `vkGetPhysicalDeviceDisplayPropertiesKHR` for the display the present operation targets then `persistent` must be `VK_FALSE`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DISPLAY_PRESENT_INFO_KHR`

If the `pNext` chain of VkPresentInfoKHR includes a `VkDeviceGroupPresentInfoKHR` structure, then that structure includes an array of device masks and a device group present mode.

The `VkDeviceGroupPresentInfoKHR` structure is defined as:

    typedef struct VkDeviceGroupPresentInfoKHR {
        VkStructureType                        sType;
        const void*                            pNext;
        uint32_t                               swapchainCount;
        const uint32_t*                        pDeviceMasks;
        VkDeviceGroupPresentModeFlagBitsKHR    mode;
    } VkDeviceGroupPresentInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `swapchainCount` is zero or the number of elements in `pDeviceMasks`.

- `pDeviceMasks` is a pointer to an array of device masks, one for each element of VkPresentInfoKHR::pSwapchains.

- `mode` is the device group present mode that will be used for this present.

If `mode` is `VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_BIT_KHR`, then each element of `pDeviceMasks` selects which instance of the swapchain image is presented. Each element of `pDeviceMasks` must have exactly one bit set, and the corresponding physical device must have a presentation engine as reported by VkDeviceGroupPresentCapabilitiesKHR.

If `mode` is `VK_DEVICE_GROUP_PRESENT_MODE_REMOTE_BIT_KHR`, then each element of `pDeviceMasks` selects which instance of the swapchain image is presented. Each element of `pDeviceMasks` must have exactly one bit set, and some physical device in the logical device must include that bit in its VkDeviceGroupPresentCapabilitiesKHR::`presentMask`.

If `mode` is `VK_DEVICE_GROUP_PRESENT_MODE_SUM_BIT_KHR`, then each element of `pDeviceMasks` selects which instances of the swapchain image are component-wise summed and the sum of those images is presented. If the sum in any component is outside the representable range, the value of that component is undefined. Each element of `pDeviceMasks` must have a value for which all set bits are set in one of the elements of VkDeviceGroupPresentCapabilitiesKHR::`presentMask`.

If `mode` is `VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_MULTI_DEVICE_BIT_KHR`, then each element of `pDeviceMasks` selects which instance(s) of the swapchain images are presented. For each bit set in each element of `pDeviceMasks`, the corresponding physical device must have a presentation engine as reported by VkDeviceGroupPresentCapabilitiesKHR.

If `VkDeviceGroupPresentInfoKHR` is not provided or `swapchainCount` is zero then the masks are considered to be `1`. If `VkDeviceGroupPresentInfoKHR` is not provided, `mode` is considered to be `VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_BIT_KHR`.

Valid Usage

- `swapchainCount` must equal `0` or VkPresentInfoKHR::`swapchainCount`

- If `mode` is `VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_BIT_KHR`, then each element of `pDeviceMasks` must have exactly one bit set, and the corresponding element of VkDeviceGroupPresentCapabilitiesKHR::`presentMask` must be non-zero

- If `mode` is `VK_DEVICE_GROUP_PRESENT_MODE_REMOTE_BIT_KHR`, then each element of `pDeviceMasks` must have exactly one bit set, and some physical device in the logical device must include that bit in its VkDeviceGroupPresentCapabilitiesKHR::`presentMask`.

- If `mode` is `VK_DEVICE_GROUP_PRESENT_MODE_SUM_BIT_KHR`, then each element of `pDeviceMasks` must have a value for which all set bits are set in one of the elements of VkDeviceGroupPresentCapabilitiesKHR::`presentMask`

- If `mode` is `VK_DEVICE_GROUP_PRESENT_MODE_LOCAL_MULTI_DEVICE_BIT_KHR`, then for each bit set in each element of `pDeviceMasks`, the corresponding element of VkDeviceGroupPresentCapabilitiesKHR::`presentMask` must be non-zero

- The value of each element of `pDeviceMasks` must be equal to the device mask passed in VkAcquireNextImageInfoKHR::`deviceMask` when the image index was last acquired

- `mode` must have exactly one bit set, and that bit must have been included in VkDeviceGroupSwapchainCreateInfoKHR::`modes`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEVICE_GROUP_PRESENT_INFO_KHR`

- If `swapchainCount` is not `0`, `pDeviceMasks` must be a valid pointer to an array of `swapchainCount` `uint32_t` values

- `mode` must be a valid VkDeviceGroupPresentModeFlagBitsKHR value

When the `VK_GOOGLE_display_timing` extension is enabled, additional fields can be specified that allow an application to specify the earliest time that an image should be displayed. This allows an application to avoid stutter that is caused by an image being displayed earlier than planned. Such stuttering can occur with both fixed and variable-refresh-rate displays, because stuttering occurs when the geometry is not correctly positioned for when the image is displayed. An application can instruct the presentation engine that an image should not be displayed earlier than a specified time by adding a `VkPresentTimesInfoGOOGLE` structure to the `pNext` chain of the `VkPresentInfoKHR` structure.

The `VkPresentTimesInfoGOOGLE` structure is defined as:

    typedef struct VkPresentTimesInfoGOOGLE {
        VkStructureType               sType;
        const void*                   pNext;
        uint32_t                      swapchainCount;
        const VkPresentTimeGOOGLE*    pTimes;
    } VkPresentTimesInfoGOOGLE;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `swapchainCount` is the number of swapchains being presented to by this command.

- `pTimes` is `NULL` or a pointer to an array of `VkPresentTimeGOOGLE` elements with `swapchainCount` entries. If not `NULL`, each element of `pTimes` contains the earliest time to present the image corresponding to the entry in the `VkPresentInfoKHR`::`pImageIndices` array.

Valid Usage

- `swapchainCount` must be the same value as `VkPresentInfoKHR`::`swapchainCount`, where `VkPresentInfoKHR` is included in the `pNext` chain of this `VkPresentTimesInfoGOOGLE` structure.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PRESENT_TIMES_INFO_GOOGLE`

- If `pTimes` is not `NULL`, `pTimes` must be a valid pointer to an array of `swapchainCount` VkPresentTimeGOOGLE structures

- `swapchainCount` must be greater than `0`

The `VkPresentTimeGOOGLE` structure is defined as:

    typedef struct VkPresentTimeGOOGLE {
        uint32_t    presentID;
        uint64_t    desiredPresentTime;
    } VkPresentTimeGOOGLE;

- `presentID` is an application-provided identification value, that can be used with the results of vkGetPastPresentationTimingGOOGLE, in order to uniquely identify this present. In order to be useful to the application, it should be unique within some period of time that is meaningful to the application.

- `desiredPresentTime` specifies that the image given should not be displayed to the user any earlier than this time. `desiredPresentTime` is a time in nanoseconds, relative to a monotonically-increasing clock (e.g. `CLOCK_MONOTONIC` (see clock_gettime(2)) on Android and Linux). A value of zero specifies that the presentation engine may display the image at any time. This is useful when the application desires to provide `presentID`, but does not need a specific `desiredPresentTime`.

When the `VK_GGP_frame_token` extension is enabled, a Google Games Platform frame token can be specified when presenting an image to a swapchain by adding a `VkPresentFrameTokenGGP` structure to the `pNext` chain of the `VkPresentInfoKHR` structure.

The `VkPresentFrameTokenGGP` structure is defined as:

    typedef struct VkPresentFrameTokenGGP {
        VkStructureType    sType;
        const void*        pNext;
        GgpFrameToken      frameToken;
    } VkPresentFrameTokenGGP;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `frameToken` is the Google Games Platform frame token.

Valid Usage

- `frameToken` must be a valid `GgpFrameToken`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PRESENT_FRAME_TOKEN_GGP`

`vkQueuePresentKHR`, releases the acquisition of the images referenced by `imageIndices`. The queue family corresponding to the queue `vkQueuePresentKHR` is executed on must have ownership of the presented images as defined in Resource Sharing. `vkQueuePresentKHR` does not alter the queue family ownership, but the presented images must not be used again before they have been reacquired using `vkAcquireNextImageKHR`.

The processing of the presentation happens in issue order with other queue operations, but semaphores have to be used to ensure that prior rendering and other commands in the specified queue complete before the presentation begins. The presentation command itself does not delay processing of subsequent commands on the queue, however, presentation requests sent to a particular queue are always performed in order. Exact presentation timing is controlled by the semantics of the presentation engine and native platform in use.

If an image is presented to a swapchain created from a display surface, the mode of the associated display will be updated, if necessary, to match the mode specified when creating the display surface. The mode switch and presentation of the specified image will be performed as one atomic operation.

The result codes `VK_ERROR_OUT_OF_DATE_KHR` and `VK_SUBOPTIMAL_KHR` have the same meaning when returned by `vkQueuePresentKHR` as they do when returned by `vkAcquireNextImageKHR`. If multiple swapchains are presented, the result code is determined applying the following rules in order:

- If the device is lost, `VK_ERROR_DEVICE_LOST` is returned.

- If any of the target surfaces are no longer available the error `VK_ERROR_SURFACE_LOST_KHR` is returned.

- If any of the presents would have a result of `VK_ERROR_OUT_OF_DATE_KHR` if issued separately then `VK_ERROR_OUT_OF_DATE_KHR` is returned.

- If any of the presents would have a result of `VK_ERROR_FULL_SCREEN_EXCLUSIVE_MODE_LOST_EXT` if issued separately then `VK_ERROR_FULL_SCREEN_EXCLUSIVE_MODE_LOST_EXT` is returned.

- If any of the presents would have a result of `VK_SUBOPTIMAL_KHR` if issued separately then `VK_SUBOPTIMAL_KHR` is returned.

- Otherwise `VK_SUCCESS` is returned.

Presentation is a read-only operation that will not affect the content of the presentable images. Upon reacquiring the image and transitioning it away from the `VK_IMAGE_LAYOUT_PRESENT_SRC_KHR` layout, the contents will be the same as they were prior to transitioning the image to the present source layout and presenting it. However, if a mechanism other than Vulkan is used to modify the platform window associated with the swapchain, the content of all presentable images in the swapchain becomes undefined.

| Note The application can continue to present any acquired images from a retired swapchain as long as the swapchain has not entered a state that causes vkQueuePresentKHR to return `VK_ERROR_OUT_OF_DATE_KHR`.

### 32.10. Hdr Metadata

To improve color reproduction of content it is useful to have information that can be used to better reproduce the colors as seen on the mastering display. That information can be provided to an implementation by calling `vkSetHdrMetadataEXT`. The metadata will be applied to the specified `VkSwapchainKHR` objects at the next `vkQueuePresentKHR` call using that `VkSwapchainKHR` object. The metadata will persist until a subsequent `vkSetHdrMetadataEXT` changes it. The definitions below are from the associated SMPTE 2086, CTA 861.3 and CIE 15:2004 specifications.

The definition of `vkSetHdrMetadataEXT` is:

    void vkSetHdrMetadataEXT(
        VkDevice                                    device,
        uint32_t                                    swapchainCount,
        const VkSwapchainKHR*                       pSwapchains,
        const VkHdrMetadataEXT*                     pMetadata);

- `device` is the logical device where the swapchain(s) were created.

- `swapchainCount` is the number of swapchains included in `pSwapchains`.

- `pSwapchains` is a pointer to an array of `swapchainCount` VkSwapchainKHR handles.

- `pMetadata` is a pointer to an array of `swapchainCount` VkHdrMetadataEXT structures.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pSwapchains` must be a valid pointer to an array of `swapchainCount` valid VkSwapchainKHR handles

- `pMetadata` must be a valid pointer to an array of `swapchainCount` valid VkHdrMetadataEXT structures

- `swapchainCount` must be greater than `0`

- Both of `device`, and the elements of `pSwapchains` must have been created, allocated, or retrieved from the same VkInstance

    typedef struct VkXYColorEXT {
        float    x;
        float    y;
    } VkXYColorEXT;

Chromaticity coordinates x and y are as specified in CIE 15:2004 “Calculation of chromaticity coordinates” (Section 7.3) and are limited to between 0 and 1 for real colors for the mastering display.

    typedef struct VkHdrMetadataEXT {
        VkStructureType    sType;
        const void*        pNext;
        VkXYColorEXT       displayPrimaryRed;
        VkXYColorEXT       displayPrimaryGreen;
        VkXYColorEXT       displayPrimaryBlue;
        VkXYColorEXT       whitePoint;
        float              maxLuminance;
        float              minLuminance;
        float              maxContentLightLevel;
        float              maxFrameAverageLightLevel;
    } VkHdrMetadataEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `displayPrimaryRed` is the mastering display’s red primary in chromaticity coordinates

- `displayPrimaryGreen` is the mastering display’s green primary in chromaticity coordinates

- `displayPrimaryBlue` is the mastering display’s blue primary in chromaticity coordinates

- `whitePoint` is the mastering display’s white-point in chromaticity coordinates

- `maxLuminance` is the maximum luminance of the mastering display in nits

- `minLuminance` is the minimum luminance of the mastering display in nits

- `maxContentLightLevel` is content’s maximum luminance in nits

- `maxFrameAverageLightLevel` is the maximum frame average light level in nits

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_HDR_METADATA_EXT`

- `pNext` must be `NULL`

| Note The validity and use of this data is outside the scope of Vulkan.

## 33. Deferred Host Operations

Certain Vulkan commands are inherently expensive for the host CPU to execute. It is often desirable to offload such work onto background threads, and to parallelize the work across multiple CPUs. The concept of deferred operations allows applications and drivers to coordinate the execution of expensive host commands using an application-managed thread pool.

The VK_KHR_deferred_host_operations extension defines the infrastructure and usage patterns for deferrable commands, but does not specify any commands as deferrable. This is left to additional dependant extensions. Commands must not be deferred unless the deferral is specifically allowed by another extension which depends on VK_KHR_deferred_host_operations. This specification will refer to such extensions as deferral extensions.

### 33.1. Requesting Deferral

The `VkDeferredOperationInfoKHR` structure is defined as:

    typedef struct VkDeferredOperationInfoKHR {
        VkStructureType           sType;
        const void*               pNext;
        VkDeferredOperationKHR    operationHandle;
    } VkDeferredOperationInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `operationHandle` is a handle to a tracking object to associate with the deferred operation.

The application can request deferral of an operation by adding this structure to the argument list of a command or by providing this in the `pNext` chain of a relevant structure for an operation when the corresponding command is invoked. If this structure is not present, no deferral is requested. If `operationHandle` is VK_NULL_HANDLE, no deferral is requested and the command proceeds as if no VkDeferredOperationInfoKHR structure was provided.

When an application requests an operation deferral, the implementation may defer the operation. When deferral is requested and the implementation defers any operation, the implementation must return `VK_OPERATION_DEFERRED_KHR` as the success code if no errors occurred. When deferral is requested, the implementation should defer the operation when the workload is significant, however if the implementation chooses not to defer any of the requested operations and instead executes all of them immediately, the implementation must return `VK_OPERATION_NOT_DEFERRED_KHR` as the success code if no errors occurred.

A deferred operation is created complete with an initial result value of `VK_SUCCESS`. The deferred operation becomes pending when an operation has been successfully deferred with that `operationHandle`.

A deferred operation is considered pending until the deferred operation completes. A pending deferred operation becomes complete when it has been fully executed by one or more threads. Pending deferred operations will never complete until they are joined by an application thread, using vkDeferredOperationJoinKHR. Applications can join multiple threads to the same deferred operation, enabling concurrent execution of subtasks within that operation.

The application can query the status of a VkDeferredOperationKHR using the vkGetDeferredOperationMaxConcurrencyKHR or vkGetDeferredOperationResultKHR commands.

From the perspective of other commands - parameters to the original command that are externally synchronized must not be accessed before the deferred operation completes, and the result of the deferred operation (e.g. object creation) are not considered complete until the deferred operation completes.

If the deferred operation is one which creates an object (for example, a pipeline object), the implementation must allocate that object as it normally would, and return a valid handle to the application. This object is a pending object, and must not be used by the application until the deferred operation is completed (unless otherwise specified by the deferral extension). When the deferred operation is complete, the application should call vkGetDeferredOperationResultKHR to obtain the result of the operation. If `vkGetDeferredOperationResultKHR` indicates failure, the application must destroy the pending object using an appropriate command, so that the implementation has an opportunity to recover the handle. The application must not perform this destruction until the deferred operation is complete. Construction of the pending object uses the same allocator which would have been used if the operation had not been deferred.

Valid Usage

- Any previous deferred operation that was associated with `operationHandle` must be complete

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEFERRED_OPERATION_INFO_KHR`

### 33.2. Deferred Host Operations API

The `VkDeferredOperationKHR` handle is defined as:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkDeferredOperationKHR)

This handle refers to a tracking structure which manages the execution state for a deferred command.

To construct the tracking object for a deferred command, call:

    VkResult vkCreateDeferredOperationKHR(
        VkDevice                                    device,
        const VkAllocationCallbacks*                pAllocator,
        VkDeferredOperationKHR*                     pDeferredOperation);

- `device` is the device which owns `operation`.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pDeferredOperation` is a pointer to a handle in which the created VkDeferredOperationKHR is returned.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pDeferredOperation` must be a valid pointer to a VkDeferredOperationKHR handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

To assign a thread to a deferred operation, call:

    VkResult vkDeferredOperationJoinKHR(
        VkDevice                                    device,
        VkDeferredOperationKHR                      operation);

- `device` is the device which owns `operation`.

- `operation` is the deferred operation that the calling thread should work on.

The `vkDeferredOperationJoinKHR` command will execute a portion of the deferred operation on the calling thread.

The return value will be one of the following:

- A return value of `VK_SUCCESS` indicates that `operation` is complete. The application should use vkGetDeferredOperationResultKHR to retrieve the result of `operation`.

- A return value of `VK_THREAD_DONE_KHR` indicates that the deferred operation is not complete, but there is no work remaining to assign to threads. Future calls to vkDeferredOperationJoinKHR are not necessary and will simply harm performance. This situation may occur when other threads executing vkDeferredOperationJoinKHR are about to complete `operation`, and the implementation is unable to partition the workload any further.

- A return value of `VK_THREAD_IDLE_KHR` indicates that the deferred operation is not complete, and there is no work for the thread to do at the time of the call. This situation may occur if the operation encounters a temporary reduction in parallelism. By returning `VK_THREAD_IDLE_KHR`, the implementation is signaling that it expects that more opportunities for parallelism will emerge as execution progresses, and that future calls to vkDeferredOperationJoinKHR can be beneficial. In the meantime, the application can perform other work on the calling thread.

Implementations must guarantee forward progress by enforcing the following invariants:

1. If only one thread has invoked vkDeferredOperationJoinKHR on a given operation, that thread must execute the operation to completion and return `VK_SUCCESS`.

2. If multiple threads have concurrently invoked vkDeferredOperationJoinKHR on the same operation, then at least one of them must complete the operation and return `VK_SUCCESS`.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `operation` must be a valid VkDeferredOperationKHR handle

- `operation` must have been created, allocated, or retrieved from `device`

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_THREAD_DONE_KHR`

  - `VK_THREAD_IDLE_KHR`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

When a deferred operation is completed, the application can destroy the tracking object by calling:

    void vkDestroyDeferredOperationKHR(
        VkDevice                                    device,
        VkDeferredOperationKHR                      operation,
        const VkAllocationCallbacks*                pAllocator);

- `device` is the device which owns `operation`.

- `operation` is the completed operation to be destroyed.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage

- If `VkAllocationCallbacks` were provided when `operation` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `operation` was created, `pAllocator` must be NULL

- `operation` must be completed

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `operation` must be a valid VkDeferredOperationKHR handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `operation` must have been created, allocated, or retrieved from `device`

The `vkGetDeferredOperationMaxConcurrencyKHR` function is defined as:

    uint32_t vkGetDeferredOperationMaxConcurrencyKHR(
        VkDevice                                    device,
        VkDeferredOperationKHR                      operation);

- `device` is the device which owns `operation`.

- `operation` is the deferred operation to be queried.

The returned value is the maximum number of threads that can usefully execute a deferred operation concurrently, reported for the state of the deferred operation at the point this command is called. This value is intended to be used to better schedule work onto available threads. Applications can join any number of threads to the deferred operation and expect it to eventually complete, though excessive joins may return `VK_THREAD_IDLE_KHR` immediately, performing no useful work.

If the deferred operation is currently joined to any threads, the value returned by this command may immediately be out of date.

Implementations must not return zero.

Implementations may return 232-1 to indicate that the maximum concurrency is unknown and cannot be easily derived. Implementations may return values larger than the maximum concurrency available on the host CPU. In these situations, an application should clamp the return value rather than oversubscribing the machine.

Valid Usage
Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `operation` must be a valid VkDeferredOperationKHR handle

- `operation` must have been created, allocated, or retrieved from `device`

The `vkGetDeferredOperationResultKHR` function is defined as:

    VkResult vkGetDeferredOperationResultKHR(
        VkDevice                                    device,
        VkDeferredOperationKHR                      operation);

- `device` is the device which owns `operation`.

- `operation` is the operation whose deferred result is being queried.

If the deferred operation is pending, `vkGetDeferredOperationResultKHR` returns `VK_NOT_READY`. Otherwise, it returns the result of the deferred operation. This value must be one of the VkResult values which could have been returned by the original command if the operation had not been deferred.

Valid Usage
Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `operation` must be a valid VkDeferredOperationKHR handle

- `operation` must have been created, allocated, or retrieved from `device`

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_NOT_READY`

## 34. Ray Traversal

Ray traversal is the process which handles intersections between a traced ray and geometry in an acceleration structure.

Ray traversal cannot be started by a Vulkan API command directly - a shader must execute `OpRayQueryProceedKHR` or `OpTraceRayKHR`. When the `rayTracing` feature is enabled, `OpTraceRayKHR` can be used for ray tracing in a ray tracing pipeline. When the `rayQuery` feature is enabled, `OpRayQueryProceedKHR` can be used in any shader stage.

### 34.1. Ray Intersection Candidate Determination

Once tracing begins, rays will be tested against geometries in an acceleration structure to determine if a hit occurred between them, initially based only on their geometric properties (i.e. their vertices). The implementation performs similar operations to that of rasterization, but with the effective viewport determined by the parameters of the ray, and the geometry transformed into a space determined by that viewport.

The acceleration structure space coordinates of each primitive are transformed according to the origin and direction of the ray as follows:

\[\left( \begin{array}{c} x_{r} \\ y_{r}\\ z_{r} \end{array} \right) = \left( \begin{array}{c} x_{as} - o_x \\ y_{as} - o_y \\ z_{as} - o_z \end{array} \right) \left( \begin{matrix} a_x^2(1-c) + c & a_xa_y(1-c) - sa_z & a_xa_z(1-c) + sa_y \\ a_xa_y(1-c) + sa_z & a_y^2(1-c) + c & a_ya_z(1-c) - sa_x \\ a_xa_z(1-c) - sa_y & a_ya_z(1-c) + sa_x & a_z^2(1-c) + c \end{matrix} \right)\]

a is the axis of rotation between k and d

\[a = \frac{k \times d}{|| k \times d ||}\]

s and c are the sine and cosine of the angle α between k and d

\[\begin{aligned} \alpha &= \arccos(u \cdot d) \\ c &= \cos(\alpha) \\ s &= \sin(\alpha) \end{aligned}\]

k is the unit vector

\[k = \left( \begin{array}{c} 0 \\ 0 \\ 1 \end{array} \right)\]

o and d are the ray origin and direction, respectively; the vector described by xas, yas, and zas is any position in acceleration structure space; and the vector described by xr, yr, and zr is the same position in ray space.

An intersection candidate is a unique point of intersection between a ray and a geometric primitive. For any primitive that has within its bounds a position xyzas such that

\[\begin{aligned} x_r &= 0 \\ y_r &= 0 \\ T_{Min} \leq z_r &\leq T_{Max} \end{aligned}\]

an intersection candidate exists.

The determination of this condition is performed in an implementation specific manner, and may be performed with floating point operations. Due to the complexity and number of operations involved, inaccuracies are expected, particularly as the scale of values involved begins to diverge. Implementations should take efforts to maintain as much precision as possible.

| Note One very common case is when geometries are close to each other at some distance from the origin in acceleration structure space, where an effect similar to "z-fighting" is likely to be observed. Applications can mitigate this by ensuring their detailed geometries remain close to the origin. Another likely case is when the origin of a ray is set to a position on a previously intersected surface, and its tmin is zero or near zero; an intersection may be detected on the emitting surface. This case can usually be mitigated by offsetting tmin slightly.

In the case of AABB geometries, implementations may increase their size in an acceleration structure in order to mitigate precision issues. This may result in false positives being reported to the application.

For triangle intersection candidates, the a and b barycentric coordinates on the triangle where the above condition is met are made available to future shading. If the ray was traced with `OpTraceRayKHR`, these values are available as a vector of 2 32-bit floating point values in the `HitAttributeKHR` storage class.

Once an intersection candidate is determined, it proceeds through the following operations, in order:

1. Ray Intersection Culling

2. Ray Intersection Confirmation

3. Ray Closest Hit Determination

4. Ray Result Determination

The sections below describe the exact details of these tests. There is no ordering guarantee between operations performed on different intersection candidates.

#### 34.1.1. Watertightness

For a set of triangles with identical transforms, within a single instance:

- Any set of two or more triangles where all triangles have one vertex with an identical position value, that vertex is a shared vertex.

- Any set of two triangles with two shared vertices that were specified in the same winding order in each triangle have a shared edge defined by those vertices.

A closed fan is a set of three or more triangles where:

- All triangles in the set have the same shared vertex as one of their vertices.

- All edges that include the above vertex are shared edges.

- All above shared edges are shared by exactly two triangles from the set.

- No two triangles in the set intersect, except at shared edges.

- Every triangle in the set is joined to every other triangle in the set by a series of the above shared edges.

Implementations should not double-hit or miss when a ray intersects a shared edge, or a shared vertex of a closed fan.

### 34.2. Ray Intersection Culling

Candidate intersections go through several phases of culling before confirmation as an actual hit. There is no particular ordering dependency between the different culling operations.

#### 34.2.1. Ray Primitive Culling

If the `rayTracingPrimitiveCulling` feature is enabled, the `SkipTrianglesKHR` and `SkipAABBsKHR` ray flags can be specified when tracing a ray.

If `SkipTrianglesKHR` was included in the `Ray Flags` operand of the ray trace instruction, and the intersection is with a triangle primitive, the intersection is dropped, and no further processing of this intersection occurs. If `VK_PIPELINE_CREATE_RAY_TRACING_SKIP_TRIANGLES_BIT_KHR` was included in the pipeline, traversal with `OpTraceKHR` calls will all behave as if `SkipTrianglesKHR` was included in its `Ray Flags` operand.

If `SkipAABBsKHR` was included in the `Ray Flags` operand of the ray trace instruction, and the intersection is with an AABB primitive, the intersection is dropped, and no further processing of this intersection occurs. If `VK_PIPELINE_CREATE_RAY_TRACING_SKIP_AABBS_BIT_KHR` was included in the pipeline, traversal with `OpTraceKHR` calls will all behave as if `SkipTrianglesKHR` was included in its `Ray Flags` operand.

#### 34.2.2. Ray Mask Culling

Instances can be made invisible to particular rays based on the value of VkAccelerationStructureInstanceKHR::`mask` used to add that instance to a top-level acceleration structure, and the `Cull Mask` parameter used to trace the ray.

For the instance which is intersected, if `mask` & `Cull Mask` == 0, the intersection is dropped, and no further processing occurs.

#### 34.2.3. Ray Face Culling

As in polygon rasterization, one of the stages of ray traversal is to determine if a triangle primitive is back- or front-facing, and primitives can be culled based on that facing.

If the intersection candidate is with an AABB primitive, this operation is skipped.

Determination

When a ray intersects a triangle primitive, the order that vertices are specified for the polygon affects whether the ray intersects the front or back face. Front or back facing is determined in the same way as they are for rasterization, based on the sign of the polygon’s area but using the ray space coordinates instead of framebuffer coordinates. One way to compute this area is:

\[a = -{1 \over 2}\sum_{i=0}^{n-1} x_r^i y_r^{i \oplus 1} - x_r^{i \oplus 1} y_r^i\]

where \(x_r^i\) and \(y_r^i\) are the x and y ray space coordinates of the ith vertex of the n-vertex polygon (vertices are numbered starting at zero for the purposes of this computation) and i ⊕ 1 is (i + 1) mod n.

If `VK_GEOMETRY_INSTANCE_TRIANGLE_FRONT_COUNTERCLOCKWISE_BIT_KHR` is included in VkAccelerationStructureInstanceKHR::`flags` for the instance containing the intersected triangle, if a is positive then the intersection is with the front face of the triangle, otherwise it is with the back face. If `VK_GEOMETRY_INSTANCE_TRIANGLE_FRONT_COUNTERCLOCKWISE_BIT_KHR` was not included, this determination is reversed. Additionally, if a is 0, the intersection candidate is treated as not intersecting with any face, irrespective of the sign.

If the ray was traced with `OpTraceRayKHR`, the `HitKindKHR` built-in is set to `HitKindFrontFacingTriangleKHR` if the intersection is with front-facing geometry, and `HitKindBackFacingTriangleKHR` if the intersection is with back-facing geometry, for shader stages considering this intersection.

If the ray was traced with `OpRayQueryProceedKHR`, `OpRayQueryGetIntersectionFrontFaceKHR` will return true for intersection candidates with front faces, or false for back faces.

Culling

If `CullBackFacingTrianglesKHR` was included in the `Ray Flags` parameter of the ray trace instruction, and the intersection is determined as with the back face of a triangle primitive, the intersection is dropped, and no further processing of this intersection occurs.

If `CullFrontFacingTrianglesKHR` was included in the `Ray Flags` parameter of the ray trace instruction, and the intersection is determined as with the front face of a triangle primitive, the intersection is dropped, and no further processing of this intersection occurs.

This culling is disabled if `VK_GEOMETRY_INSTANCE_TRIANGLE_FACING_CULL_DISABLE_BIT_KHR` was included in VkAccelerationStructureInstanceKHR::`flags` for the instance which the intersected geometry belongs to.

Intersection candidates that have not intersected with any face (a == 0) are unconditionally culled, irrespective of ray flags and geometry instance flags.

#### 34.2.4. Ray Opacity Culling

Each geometry in the acceleration structure may be considered either opaque or not. Opaque geometries continue through traversal as normal, whereas non-opaque geometries need to be either confirmed or discarded by shader code. Intersection candidates can also be culled based on their opacity.

Determination

Each individual intersection candidate is initally determined as opaque if `VK_GEOMETRY_OPAQUE_BIT_KHR` was included in the VkAccelerationStructureGeometryKHR::`flags` when the geometry it intersected with was built, otherwise it is considered non-opaque.

If the intersection candidate was generated by an intersection shader, the intersection is initially considered to have opacity matching the AABB candidate that it was generated from.

However, this opacity can be overridden when it is built into an instance. Setting `VK_GEOMETRY_INSTANCE_FORCE_OPAQUE_BIT_KHR` in VkAccelerationStructureInstanceKHR::`flags` will force all geometries in the instance to be considered opaque. Similarly, setting `VK_GEOMETRY_INSTANCE_FORCE_NO_OPAQUE_BIT_KHR` will force all geometries in the instance to be considered non-opaque.

This can again be overridden by including `OpaqueKHR` or `NoOpaqueKHR` in the `Ray Flags` parameter when tracing a ray. `OpaqueKHR` forces all geometries to behave as if they are opaque, regardless of their build parameters. Similarly, `NoOpaqueKHR` forces all geometries to behave as if they are non-opaque.

If the ray was traced with `OpRayQueryProceedKHR`, to determine the opacity of AABB intersection candidates, `OpRayQueryGetIntersectionCandidateAABBOpaqueKHR` can be used. This instruction will return `true` for opaque intersection candidates, and `false` for non-opaque intersection candidates.

Culling

If `CullOpaqueKHR` is included in the `Ray Flags` parameter when tracing a ray, an intersection with a geometry that is considered opaque is dropped, and no further processing occurs.

If `CullNoOpaqueKHR` is included in the `Ray Flags` parameter when tracing a ray, an intersection with a geometry that is considered non-opaque is dropped, and no further processing occurs.

### 34.3. Ray Intersection Confirmation

Depending on the opacity of intersected geometry and whether it’s a triangle or AABB, candidate intersections are further processed to determine the eventual hit result. Candidates generated from AABB intersections run through the same confirmation process as triangle hits.

#### 34.3.1. AABB Intersection Candidates

For intersection candidates with an AABB geometry generated by [Ray Intersection Candidate Determination], shader code is executed to determine whether any hits should be reported to the traversal infrastructure; no further processing of this intersection candidate occurs.

If the ray was traced with `OpTraceRayKHR`, an intersection shader is invoked from the Shader Binding Table according to the specified indexing for the intersected geometry. If this shader calls `OpReportIntersectionKHR`, a new intersection candidate is generated as described below.

Each new candidate generated as a result of this processing is a generated intersection candidate that intersects the AABB geometry, with a t value equal to the `Hit` parameter of the `OpReportIntersectionKHR` instruction. The new generated candidate is then independently run through [Ray Intersection Confirmation] as a generated intersection.

If the ray was traced with `OpRayQueryProceedKHR`, control is returned to the shader which executed `OpRayQueryProceedKHR`, returning `true`. The resulting ray query has a candidate intersection type of `RayQueryCandidateIntersectionAABBKHR`. `OpRayQueryGenerateIntersectionKHR` can be called to commit a new intersection candidate with committed intersection type of `RayQueryCommittedIntersectionGeneratedKHR`. Further ray query processing can be continued by executing `OpRayQueryProceedKHR` with the same ray query, or intersection can be terminated with `OpRayQueryTerminateKHR`. Unlike rays traced with `OpTraceKHR`, candidates generated in this way skip generated intersection candidate confirmation; applications should make this determination before generating the intersection.

This operation may be executed multiple times for the same intersection candidate.

#### 34.3.2. Triangle and Generated Intersection Candidates

For triangle and generated intersection candidates, additional shader code may be executed based on the intersections opacity.

If the intersection is opaque, the candidate is immediately confirmed as a valid hit and passes to the next stage of processing.

For non-opaque intersection candidates, shader code is executed to determine whether a hit occurred or not.

If the ray was traced with `OpTraceRayKHR`, an any hit shader is invoked from the Shader Binding Table according to the specified indexing. If this shader calls `OpIgnoreIntersectionKHR`, the candidate is dropped and no further processing of the candidate occurs. If the any hit shader identified is `VK_SHADER_UNUSED_KHR`, the candidate is immediately confirmed as a valid hit and passes to the next stage of processing.

If the ray was traced with `OpRayQueryProceedKHR`, control is returned to the shader which executed `OpRayQueryProceedKHR`, returning `true`. As only triangle candidates participate in this operation with ray queries, the resulting candidate intersection type is always `RayQueryCandidateIntersectionTriangleKHR`. `OpRayQueryConfirmIntersectionKHR` can be called on the ray query to confirm the candidate as a hit with committed intersection type of `RayQueryCommittedIntersectionTriangleKHR`. Further ray query processing can be continued by executing `OpRayQueryProceedKHR` with the same ray query, or intersection can be terminated with `OpRayQueryTerminateKHR`. If `OpRayQueryConfirmIntersectionKHR` has not been executed, the candidate is dropped and no further processing of the candidate occurs.

This operation may be executed multiple times for the same intersection candidate unless `VK_GEOMETRY_NO_DUPLICATE_ANY_HIT_INVOCATION_BIT_KHR` was specified for the intersected geometry.

### 34.4. Ray Closest Hit Determination

Unless the ray was traced with the `TerminateOnFirstHitKHR` ray flag, the implementation must track the closest confirmed hit until all geometries have been tested and either confirmed or dropped.

After an intersection candidate is confirmed, its t value is compared to tmax to determine which intersection is closer, where t is the parametric distance along the ray at which the intersection occurred.

- If t < tmax, tmax is set to t and the candidate is set as the current closest hit.

- If t > tmax, the candidate is dropped and no further processing of that candidate occurs.

- If t = tmax, the candidate may be set as the current closest hit or dropped.

If `TerminateOnFirstHitKHR` was included in the `Ray Flags` used to trace the ray, once the first hit is confirmed, the ray trace is terminated.

### 34.5. Ray Result Determination

Once all candidates have finished processing the prior stages, or if the ray is forcibly terminated, the final result of the ray trace is determined.

If a closest hit result was identified by Ray Closest Hit Determination, a closest hit has occurred, otherwise the final result is a miss.

For rays traced with `OpTraceRayKHR`, if a closest hit result was identified, a closest-hit shader is invoked from the Shader Binding Table according to the specified indexing for the intersected geometry. Control returns to the shader that executed `OpTraceRayKHR` once this shader returns. This shader is skipped if either the ray flags included `SkipClosestHitShaderKHR`, or if the closest-hit shader identified is `VK_SHADER_UNUSED_NV`.

For rays traced with `OpTraceRayKHR` where no hit result was identified, the miss shader identified by the `Miss Index` parameter of `OpTraceRayKHR` is invoked. Control returns to the shader that executed `OpTraceRayKHR` once this shader returns.

If the ray was traced with `OpRayQueryProceedKHR`, control is returned to the shader which executed `OpRayQueryProceedKHR`, returning `false`. If a closest hit was identified by Ray Closest Hit Determination, the ray query will now have a committed intersection type of `RayQueryCommittedIntersectionGeneratedKHR` or `RayQueryCommittedIntersectionTriangleKHR`. If no closest hit was identified, the committed intersection type will be `RayQueryCommittedIntersectionNoneKHR`.

No further processing of a ray query occurs after this result is determined.

## 35. Ray Tracing

Ray tracing uses a separate rendering pipeline from both the graphics and compute pipelines (see Ray Tracing Pipeline).

Figure 24. Ray tracing pipeline execution
Caption

Interaction between the different shader stages in the ray tracing pipeline

Within the ray tracing pipeline, `OpTraceRayKHR` can be called to perform a ray traversal that invokes the various ray tracing shader stages during its execution. The relationship between the ray tracing pipeline object and the geometries present in the acceleration structure traversed is passed into the ray tracing command in a VkBuffer object known as a shader binding table. `OpExecuteCallableKHR` can also be used in ray tracing pipelines to invoke a callable shader.

During execution, control alternates between scheduling and other operations. The scheduling functionality is implementation-specific and is responsible for workload execution. The shader stages are programmable. Traversal, which refers to the process of traversing acceleration structures to find potential intersections of rays with geometry, is fixed function.

The programmable portions of the pipeline are exposed in a single-ray programming model, with each invocation handling one ray at a time. Memory operations can be synchronized using standard memory barriers. The `Workgroup` scope and variables with a storage class of `Workgroup` must not be used in the ray tracing pipeline.

### 35.1. Shader Call Instructions

A shader call is an instruction which may cause execution to continue elsewhere by creating one or more invocations that execute a different shader stage.

The shader call instructions are:

- `OpTraceRayKHR` which may invoke intersection, any-hit, closest hit, or miss shaders,

- `OpReportIntersectionKHR` which may invoke any-hit shaders, and

- `OpExecuteCallableKHR` which will invoke a callable shader.

The invocations created by shader call instructions are grouped into subgroups by the implementation. Those subgroups may be unrelated to the subgroup of the parent invocation.

Shader call instructions can be used recursively; invoked shaders can themselves execute shader call instructions, to a maximum depth defined by the `maxRecursionDepth` limit.

Shaders directly invoked from the API always have a recursion depth of 0; each shader executed by a shader call instruction has a recursion depth one higher than the recursion depth of the shader which invoked it. Applications must not invoke a shader with a recursion depth greater than the value of `maxRecursionDepth` specified in the pipeline.

An invocation repack instruction is a ray tracing shader call instruction where the implementation may change the set of invocations that are executing. When a repack instruction is encountered, the invocation is suspended and a new invocation begins and executes the instruction. After executing the repack instruction (which may result in other ray tracing shader stages executing) the new invocation ends and the original invocation is resumed, but it may be resumed in a different subgroup or at a different `SubgroupLocalInvocationId` within the same subgroup. When a subset of invocations in a subgroup execute the invocation repack instruction, those that do not execute it remain in the same subgroup at the same `SubgroupLocalInvocationId`.

The `OpTraceRayKHR`, `OpReportIntersectionKHR`, and `OpExecuteCallableKHR` instructions are invocation repack instructions.

The invocations that are executing before an invocation repack instruction, after the instruction, or are created by the instruction, are shader-call-related.

If the implementation changes the composition of subgroups, the values of `SubgroupLocalInvocationId`, `SMIDNV`, `WarpIDNV`, and builtin variables that are derived from them (`SubgroupEqMask`, `SubgroupGeMask`, `SubgroupGtMask`, `SubgroupLeMask`, `SubgroupLtMask`) must be changed accordingly by the invocation repack instruction.

| Note Subgroup operations are permitted in the programmable ray tracing shader stages. However, shader call instructions place a bound on where results of subgroup instructions or subgroup-scoped instructions that execute the dynamic instance of that instruction are potentially valid. For example, care must be taken when using the result of a ballot operation that was computed before an invocation repack instruction, after that repack instruction. The ballot may be incorrect as the set of invocations could have changed. For clock operations, the value of a `Subgroup` scoped `OpReadClockKHR` read before the dynamic instance of a repack instruction should not be compared to the result of that clock instruction after the repack instruction.

When a ray tracing shader executes a dynamic instance of an invocation repack instruction which results in another ray tracing shader being invoked, their instructions are related by shader-call-order.

For ray tracing invocations that are shader-call-related:

- memory operations on `StorageBuffer`, `Image`, and `ShaderRecordBufferKHR` storage classes can be synchronized using the `ShaderCallKHR` scope.

- the `CallableDataKHR`, `IncomingCallableDataKHR`, `RayPayloadKHR`, `HitAttributeKHR`, and `IncomingRayPayloadKHR` storage classes are system-synchronized and no application availability and visibility operations are required.

- memory operations within a single invocation before and after the invocation repack instruction are ordered by program-order and do not require explicit synchronzation.

### 35.2. Ray Tracing Commands

Ray tracing commands provoke work in the ray tracing pipeline. Ray tracing commands are recorded into a command buffer and when executed by a queue will produce work that executes according to the currently bound ray tracing pipeline. A ray tracing pipeline must be bound to a command buffer before any ray tracing commands are recorded in that command buffer.

To dispatch ray tracing use:

    void vkCmdTraceRaysNV(
        VkCommandBuffer                             commandBuffer,
        VkBuffer                                    raygenShaderBindingTableBuffer,
        VkDeviceSize                                raygenShaderBindingOffset,
        VkBuffer                                    missShaderBindingTableBuffer,
        VkDeviceSize                                missShaderBindingOffset,
        VkDeviceSize                                missShaderBindingStride,
        VkBuffer                                    hitShaderBindingTableBuffer,
        VkDeviceSize                                hitShaderBindingOffset,
        VkDeviceSize                                hitShaderBindingStride,
        VkBuffer                                    callableShaderBindingTableBuffer,
        VkDeviceSize                                callableShaderBindingOffset,
        VkDeviceSize                                callableShaderBindingStride,
        uint32_t                                    width,
        uint32_t                                    height,
        uint32_t                                    depth);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `raygenShaderBindingTableBuffer` is the buffer object that holds the shader binding table data for the ray generation shader stage.

- `raygenShaderBindingOffset` is the offset in bytes (relative to `raygenShaderBindingTableBuffer`) of the ray generation shader being used for the trace.

- `missShaderBindingTableBuffer` is the buffer object that holds the shader binding table data for the miss shader stage.

- `missShaderBindingOffset` is the offset in bytes (relative to `missShaderBindingTableBuffer`) of the miss shader being used for the trace.

- `missShaderBindingStride` is the size in bytes of each shader binding table record in `missShaderBindingTableBuffer`.

- `hitShaderBindingTableBuffer` is the buffer object that holds the shader binding table data for the hit shader stages.

- `hitShaderBindingOffset` is the offset in bytes (relative to `hitShaderBindingTableBuffer`) of the hit shader group being used for the trace.

- `hitShaderBindingStride` is the size in bytes of each shader binding table record in `hitShaderBindingTableBuffer`.

- `callableShaderBindingTableBuffer` is the buffer object that holds the shader binding table data for the callable shader stage.

- `callableShaderBindingOffset` is the offset in bytes (relative to `callableShaderBindingTableBuffer`) of the callable shader being used for the trace.

- `callableShaderBindingStride` is the size in bytes of each shader binding table record in `callableShaderBindingTableBuffer`.

- `width` is the width of the ray trace query dimensions.

- `height` is height of the ray trace query dimensions.

- `depth` is depth of the ray trace query dimensions.

When the command is executed, a ray generation group of `width` × `height` × `depth` rays is assembled.

Valid Usage

- If a `VkImageView` is sampled with `VK_FILTER_LINEAR` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT`

- If a `VkImageView` is accessed using atomic operations as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT`

- If a `VkImageView` is sampled with `VK_FILTER_CUBIC_EXT` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_EXT`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` as a result of this command must have a VkImageViewType and format that supports cubic filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubic` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` with a reduction mode of either `VK_SAMPLER_REDUCTION_MODE_MIN` or `VK_SAMPLER_REDUCTION_MODE_MAX` as a result of this command must have a VkImageViewType and format that supports cubic filtering together with minmax filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubicMinmax` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImage created with a VkImageCreateInfo::`flags` containing `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV` sampled as a result of this command must only be sampled using a VkSamplerAddressMode of `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`.

- For each set n that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a descriptor set must have been bound to n at the same pipeline bind point, with a `VkPipelineLayout` that is compatible for set n, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- For each push constant that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a push constant value must have been set for the same pipeline bind point, with a `VkPipelineLayout` that is compatible for push constants, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- Descriptors in each bound descriptor set, specified via `vkCmdBindDescriptorSets`, must be valid if they are statically used by the `VkPipeline` bound to the pipeline bind point used by this command

- A valid pipeline must be bound to the pipeline bind point used by this command

- If the `VkPipeline` object bound to the pipeline bind point used by this command requires any dynamic state, that state must have been set for `commandBuffer`, and done so after any previously bound pipeline with the corresponding state not specified as dynamic

- There must not have been any calls to dynamic state setting commands for any state not specified as dynamic in the `VkPipeline` object bound to the pipeline bind point used by this command, since that pipeline was bound

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used to sample from any `VkImage` with a `VkImageView` of the type `VK_IMAGE_VIEW_TYPE_3D`, `VK_IMAGE_VIEW_TYPE_CUBE`, `VK_IMAGE_VIEW_TYPE_1D_ARRAY`, `VK_IMAGE_VIEW_TYPE_2D_ARRAY` or `VK_IMAGE_VIEW_TYPE_CUBE_ARRAY`, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions with `ImplicitLod`, `Dref` or `Proj` in their name, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions that includes a LOD bias or any offset values, in any shader stage

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a uniform buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a storage buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If `commandBuffer` is an unprotected command buffer, any resource accessed by the `VkPipeline` object bound to the pipeline bind point used by this command must not be a protected resource

- `raygenShaderBindingOffset` must be less than the size of `raygenShaderBindingTableBuffer`

- `raygenShaderBindingOffset` must be a multiple of `VkPhysicalDeviceRayTracingPropertiesKHR`::`shaderGroupBaseAlignment`

- `missShaderBindingOffset` must be less than the size of `missShaderBindingTableBuffer`

- `missShaderBindingOffset` must be a multiple of `VkPhysicalDeviceRayTracingPropertiesKHR`::`shaderGroupBaseAlignment`

- `hitShaderBindingOffset` must be less than the size of `hitShaderBindingTableBuffer`

- `hitShaderBindingOffset` must be a multiple of `VkPhysicalDeviceRayTracingPropertiesKHR`::`shaderGroupBaseAlignment`

- `callableShaderBindingOffset` must be less than the size of `callableShaderBindingTableBuffer`

- `callableShaderBindingOffset` must be a multiple of `VkPhysicalDeviceRayTracingPropertiesKHR`::`shaderGroupBaseAlignment`

- `missShaderBindingStride` must be a multiple of `VkPhysicalDeviceRayTracingPropertiesKHR`::`shaderGroupHandleSize`

- `hitShaderBindingStride` must be a multiple of `VkPhysicalDeviceRayTracingPropertiesKHR`::`shaderGroupHandleSize`

- `callableShaderBindingStride` must be a multiple of `VkPhysicalDeviceRayTracingPropertiesKHR`::`shaderGroupHandleSize`

- `missShaderBindingStride` must be less than or equal to `VkPhysicalDeviceRayTracingPropertiesKHR`::`maxShaderGroupStride`

- `hitShaderBindingStride` must be less than or equal to `VkPhysicalDeviceRayTracingPropertiesKHR`::`maxShaderGroupStride`

- `callableShaderBindingStride` must be less than or equal to `VkPhysicalDeviceRayTracingPropertiesKHR`::`maxShaderGroupStride`

- Any shader group handle referenced by this call must have been queried from the currently bound ray tracing shader pipeline

- This command must not cause a shader call instruction to be executed from a shader invocation with a recursion depth greater than the value of `maxRecursionDepth` used to create the bound ray tracing pipeline.

- If `commandBuffer` is a protected command buffer, any resource written to by the `VkPipeline` object bound to the pipeline bind point used by this command must not be an unprotected resource

- If `commandBuffer` is a protected command buffer, pipeline stages other than the framebuffer-space and compute stages in the `VkPipeline` object bound to the pipeline bind point must not write to any resource

- `width` must be less than or equal to `VkPhysicalDeviceLimits`::`maxComputeWorkGroupCount`[0]

- `height` must be less than or equal to `VkPhysicalDeviceLimits`::`maxComputeWorkGroupCount`[1]

- `depth` must be less than or equal to `VkPhysicalDeviceLimits`::`maxComputeWorkGroupCount`[2]

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `raygenShaderBindingTableBuffer` must be a valid VkBuffer handle

- If `missShaderBindingTableBuffer` is not VK_NULL_HANDLE, `missShaderBindingTableBuffer` must be a valid VkBuffer handle

- If `hitShaderBindingTableBuffer` is not VK_NULL_HANDLE, `hitShaderBindingTableBuffer` must be a valid VkBuffer handle

- If `callableShaderBindingTableBuffer` is not VK_NULL_HANDLE, `callableShaderBindingTableBuffer` must be a valid VkBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support compute operations

- This command must only be called outside of a render pass instance

- Each of `callableShaderBindingTableBuffer`, `commandBuffer`, `hitShaderBindingTableBuffer`, `missShaderBindingTableBuffer`, and `raygenShaderBindingTableBuffer` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Compute |

To dispatch ray tracing use:

    void vkCmdTraceRaysKHR(
        VkCommandBuffer                             commandBuffer,
        const VkStridedBufferRegionKHR*             pRaygenShaderBindingTable,
        const VkStridedBufferRegionKHR*             pMissShaderBindingTable,
        const VkStridedBufferRegionKHR*             pHitShaderBindingTable,
        const VkStridedBufferRegionKHR*             pCallableShaderBindingTable,
        uint32_t                                    width,
        uint32_t                                    height,
        uint32_t                                    depth);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `pRaygenShaderBindingTable` is the strided buffer range that holds the shader binding table data for the ray generation shader stage.

- `pMissShaderBindingTable` is the strided buffer range that holds the shader binding table data for the miss shader stage.

- `pHitShaderBindingTable` is the strided buffer range that holds the shader binding table data for the hit shader stage.

- `pCallableShaderBindingTable` is the strided buffer range that holds the shader binding table data for the callable shader stage.

- `width` is the width of the ray trace query dimensions.

- `height` is height of the ray trace query dimensions.

- `depth` is depth of the ray trace query dimensions.

When the command is executed, a ray generation group of `width` × `height` × `depth` rays is assembled.

Valid Usage

- If a `VkImageView` is sampled with `VK_FILTER_LINEAR` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT`

- If a `VkImageView` is accessed using atomic operations as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT`

- If a `VkImageView` is sampled with `VK_FILTER_CUBIC_EXT` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_EXT`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` as a result of this command must have a VkImageViewType and format that supports cubic filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubic` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` with a reduction mode of either `VK_SAMPLER_REDUCTION_MODE_MIN` or `VK_SAMPLER_REDUCTION_MODE_MAX` as a result of this command must have a VkImageViewType and format that supports cubic filtering together with minmax filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubicMinmax` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImage created with a VkImageCreateInfo::`flags` containing `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV` sampled as a result of this command must only be sampled using a VkSamplerAddressMode of `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`.

- For each set n that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a descriptor set must have been bound to n at the same pipeline bind point, with a `VkPipelineLayout` that is compatible for set n, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- For each push constant that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a push constant value must have been set for the same pipeline bind point, with a `VkPipelineLayout` that is compatible for push constants, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- Descriptors in each bound descriptor set, specified via `vkCmdBindDescriptorSets`, must be valid if they are statically used by the `VkPipeline` bound to the pipeline bind point used by this command

- A valid pipeline must be bound to the pipeline bind point used by this command

- If the `VkPipeline` object bound to the pipeline bind point used by this command requires any dynamic state, that state must have been set for `commandBuffer`, and done so after any previously bound pipeline with the corresponding state not specified as dynamic

- There must not have been any calls to dynamic state setting commands for any state not specified as dynamic in the `VkPipeline` object bound to the pipeline bind point used by this command, since that pipeline was bound

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used to sample from any `VkImage` with a `VkImageView` of the type `VK_IMAGE_VIEW_TYPE_3D`, `VK_IMAGE_VIEW_TYPE_CUBE`, `VK_IMAGE_VIEW_TYPE_1D_ARRAY`, `VK_IMAGE_VIEW_TYPE_2D_ARRAY` or `VK_IMAGE_VIEW_TYPE_CUBE_ARRAY`, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions with `ImplicitLod`, `Dref` or `Proj` in their name, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions that includes a LOD bias or any offset values, in any shader stage

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a uniform buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a storage buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If `commandBuffer` is an unprotected command buffer, any resource accessed by the `VkPipeline` object bound to the pipeline bind point used by this command must not be a protected resource

- `raygenShaderBindingOffset` must be less than the size of `raygenShaderBindingTableBuffer`

- `raygenShaderBindingOffset` must be a multiple of `VkPhysicalDeviceRayTracingPropertiesKHR`::`shaderGroupBaseAlignment`

- `missShaderBindingOffset` must be less than the size of `missShaderBindingTableBuffer`

- `missShaderBindingOffset` must be a multiple of `VkPhysicalDeviceRayTracingPropertiesKHR`::`shaderGroupBaseAlignment`

- `hitShaderBindingOffset` must be less than the size of `hitShaderBindingTableBuffer`

- `hitShaderBindingOffset` must be a multiple of `VkPhysicalDeviceRayTracingPropertiesKHR`::`shaderGroupBaseAlignment`

- `callableShaderBindingOffset` must be less than the size of `callableShaderBindingTableBuffer`

- `callableShaderBindingOffset` must be a multiple of `VkPhysicalDeviceRayTracingPropertiesKHR`::`shaderGroupBaseAlignment`

- `missShaderBindingStride` must be a multiple of `VkPhysicalDeviceRayTracingPropertiesKHR`::`shaderGroupHandleSize`

- `hitShaderBindingStride` must be a multiple of `VkPhysicalDeviceRayTracingPropertiesKHR`::`shaderGroupHandleSize`

- `callableShaderBindingStride` must be a multiple of `VkPhysicalDeviceRayTracingPropertiesKHR`::`shaderGroupHandleSize`

- `missShaderBindingStride` must be less than or equal to `VkPhysicalDeviceRayTracingPropertiesKHR`::`maxShaderGroupStride`

- `hitShaderBindingStride` must be less than or equal to `VkPhysicalDeviceRayTracingPropertiesKHR`::`maxShaderGroupStride`

- `callableShaderBindingStride` must be less than or equal to `VkPhysicalDeviceRayTracingPropertiesKHR`::`maxShaderGroupStride`

- Any shader group handle referenced by this call must have been queried from the currently bound ray tracing shader pipeline

- This command must not cause a shader call instruction to be executed from a shader invocation with a recursion depth greater than the value of `maxRecursionDepth` used to create the bound ray tracing pipeline.

- If `commandBuffer` is a protected command buffer, any resource written to by the `VkPipeline` object bound to the pipeline bind point used by this command must not be an unprotected resource

- If `commandBuffer` is a protected command buffer, pipeline stages other than the framebuffer-space and compute stages in the `VkPipeline` object bound to the pipeline bind point must not write to any resource

- `width` must be less than or equal to `VkPhysicalDeviceLimits`::`maxComputeWorkGroupCount`[0]

- `height` must be less than or equal to `VkPhysicalDeviceLimits`::`maxComputeWorkGroupCount`[1]

- `depth` must be less than or equal to `VkPhysicalDeviceLimits`::`maxComputeWorkGroupCount`[2]

- If the currently bound ray tracing pipeline was created with `flags` that included `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_ANY_HIT_SHADERS_BIT_KHR`, the `buffer` member of `hitShaderBindingTable` must not be VK_NULL_HANDLE

- If the currently bound ray tracing pipeline was created with `flags` that included `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_CLOSEST_HIT_SHADERS_BIT_KHR`, the `buffer` member of `hitShaderBindingTable` must not be VK_NULL_HANDLE

- If the currently bound ray tracing pipeline was created with `flags` that included `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_INTERSECTION_SHADERS_BIT_KHR`, the `buffer` member of `hitShaderBindingTable` must not be VK_NULL_HANDLE

- If the currently bound ray tracing pipeline was created with `flags` that included `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_MISS_SHADERS_BIT_KHR`, the shader group handle identified by `missShaderBindingTable` must contain a valid miss shader

- If the currently bound ray tracing pipeline was created with `flags` that included `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_ANY_HIT_SHADERS_BIT_KHR`, entries in `hitShaderBindingTable` accessed as a result of this command in order to execute an any hit shader must not be set to zero

- If the currently bound ray tracing pipeline was created with `flags` that included `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_CLOSEST_HIT_SHADERS_BIT_KHR`, entries in `hitShaderBindingTable` accessed as a result of this command in order to execute a closest hit shader must not be set to zero

- If the currently bound ray tracing pipeline was created with `flags` that included `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_INTERSECTION_SHADERS_BIT_KHR`, entries in `hitShaderBindingTable` accessed as a result of this command in order to execute an intersection shader must not be set to zero

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pRaygenShaderBindingTable` must be a valid pointer to a valid VkStridedBufferRegionKHR structure

- `pMissShaderBindingTable` must be a valid pointer to a valid VkStridedBufferRegionKHR structure

- `pHitShaderBindingTable` must be a valid pointer to a valid VkStridedBufferRegionKHR structure

- `pCallableShaderBindingTable` must be a valid pointer to a valid VkStridedBufferRegionKHR structure

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support compute operations

- This command must only be called outside of a render pass instance

Host Synchronization

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Compute |

The `VkStridedBufferRegionKHR` structure is defined as:

    typedef struct VkStridedBufferRegionKHR {
        VkBuffer        buffer;
        VkDeviceSize    offset;
        VkDeviceSize    stride;
        VkDeviceSize    size;
    } VkStridedBufferRegionKHR;

- `buffer` is the buffer containing this region.

- `offset` is the byte offset in `buffer` at which the region starts.

- `stride` is the byte stride between consecutive elements.

- `size` is the size in bytes of the region starting at `offset`.

Valid Usage

- If `buffer` is not VK_NULL_HANDLE, `size` plus `offset` must be less than or equal to the size of `buffer`

- If `buffer` is not VK_NULL_HANDLE, `stride` must be less than the size of `buffer`

Valid Usage (Implicit)

- If `buffer` is not VK_NULL_HANDLE, `buffer` must be a valid VkBuffer handle

To dispatch ray tracing, with some parameters sourced on the device, use:

    void vkCmdTraceRaysIndirectKHR(
        VkCommandBuffer                             commandBuffer,
        const VkStridedBufferRegionKHR*             pRaygenShaderBindingTable,
        const VkStridedBufferRegionKHR*             pMissShaderBindingTable,
        const VkStridedBufferRegionKHR*             pHitShaderBindingTable,
        const VkStridedBufferRegionKHR*             pCallableShaderBindingTable,
        VkBuffer                                    buffer,
        VkDeviceSize                                offset);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `pRaygenShaderBindingTable` is the strided buffer range that holds the shader binding table data for the ray generation shader stage.

- `pMissShaderBindingTable` is the strided buffer range that holds the shader binding table data for the miss shader stage.

- `pHitShaderBindingTable` is the strided buffer range that holds the shader binding table data for the hit shader stage.

- `pCallableShaderBindingTable` is the strided buffer range that holds the shader binding table data for the callable shader stage.

- `buffer` is the buffer containing the trace ray parameters.

- `offset` is the byte offset into `buffer` where parameters begin.

`vkCmdTraceRaysIndirectKHR` behaves similarly to vkCmdTraceRaysKHR except that the ray trace query dimensions are read by the device from a buffer during execution. The parameters of trace ray are encoded in the VkTraceRaysIndirectCommandKHR structure.

Valid Usage

- If a `VkImageView` is sampled with `VK_FILTER_LINEAR` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT`

- If a `VkImageView` is accessed using atomic operations as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT`

- If a `VkImageView` is sampled with `VK_FILTER_CUBIC_EXT` as a result of this command, then the image view’s format features must contain `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_EXT`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` as a result of this command must have a VkImageViewType and format that supports cubic filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubic` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImageView being sampled with `VK_FILTER_CUBIC_EXT` with a reduction mode of either `VK_SAMPLER_REDUCTION_MODE_MIN` or `VK_SAMPLER_REDUCTION_MODE_MAX` as a result of this command must have a VkImageViewType and format that supports cubic filtering together with minmax filtering, as specified by `VkFilterCubicImageViewImageFormatPropertiesEXT`::`filterCubicMinmax` returned by `vkGetPhysicalDeviceImageFormatProperties2`

- Any VkImage created with a VkImageCreateInfo::`flags` containing `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV` sampled as a result of this command must only be sampled using a VkSamplerAddressMode of `VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE`.

- For each set n that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a descriptor set must have been bound to n at the same pipeline bind point, with a `VkPipelineLayout` that is compatible for set n, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- For each push constant that is statically used by the `VkPipeline` bound to the pipeline bind point used by this command, a push constant value must have been set for the same pipeline bind point, with a `VkPipelineLayout` that is compatible for push constants, with the `VkPipelineLayout` used to create the current `VkPipeline`, as described in Pipeline Layout Compatibility

- Descriptors in each bound descriptor set, specified via `vkCmdBindDescriptorSets`, must be valid if they are statically used by the `VkPipeline` bound to the pipeline bind point used by this command

- A valid pipeline must be bound to the pipeline bind point used by this command

- If the `VkPipeline` object bound to the pipeline bind point used by this command requires any dynamic state, that state must have been set for `commandBuffer`, and done so after any previously bound pipeline with the corresponding state not specified as dynamic

- There must not have been any calls to dynamic state setting commands for any state not specified as dynamic in the `VkPipeline` object bound to the pipeline bind point used by this command, since that pipeline was bound

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used to sample from any `VkImage` with a `VkImageView` of the type `VK_IMAGE_VIEW_TYPE_3D`, `VK_IMAGE_VIEW_TYPE_CUBE`, `VK_IMAGE_VIEW_TYPE_1D_ARRAY`, `VK_IMAGE_VIEW_TYPE_2D_ARRAY` or `VK_IMAGE_VIEW_TYPE_CUBE_ARRAY`, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions with `ImplicitLod`, `Dref` or `Proj` in their name, in any shader stage

- If the `VkPipeline` object bound to the pipeline bind point used by this command accesses a `VkSampler` object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V `OpImageSample*` or `OpImageSparseSample*` instructions that includes a LOD bias or any offset values, in any shader stage

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a uniform buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If the robust buffer access feature is not enabled, and if the `VkPipeline` object bound to the pipeline bind point used by this command accesses a storage buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point

- If `commandBuffer` is an unprotected command buffer, any resource accessed by the `VkPipeline` object bound to the pipeline bind point used by this command must not be a protected resource

- `raygenShaderBindingOffset` must be less than the size of `raygenShaderBindingTableBuffer`

- `raygenShaderBindingOffset` must be a multiple of `VkPhysicalDeviceRayTracingPropertiesKHR`::`shaderGroupBaseAlignment`

- `missShaderBindingOffset` must be less than the size of `missShaderBindingTableBuffer`

- `missShaderBindingOffset` must be a multiple of `VkPhysicalDeviceRayTracingPropertiesKHR`::`shaderGroupBaseAlignment`

- `hitShaderBindingOffset` must be less than the size of `hitShaderBindingTableBuffer`

- `hitShaderBindingOffset` must be a multiple of `VkPhysicalDeviceRayTracingPropertiesKHR`::`shaderGroupBaseAlignment`

- `callableShaderBindingOffset` must be less than the size of `callableShaderBindingTableBuffer`

- `callableShaderBindingOffset` must be a multiple of `VkPhysicalDeviceRayTracingPropertiesKHR`::`shaderGroupBaseAlignment`

- `missShaderBindingStride` must be a multiple of `VkPhysicalDeviceRayTracingPropertiesKHR`::`shaderGroupHandleSize`

- `hitShaderBindingStride` must be a multiple of `VkPhysicalDeviceRayTracingPropertiesKHR`::`shaderGroupHandleSize`

- `callableShaderBindingStride` must be a multiple of `VkPhysicalDeviceRayTracingPropertiesKHR`::`shaderGroupHandleSize`

- `missShaderBindingStride` must be less than or equal to `VkPhysicalDeviceRayTracingPropertiesKHR`::`maxShaderGroupStride`

- `hitShaderBindingStride` must be less than or equal to `VkPhysicalDeviceRayTracingPropertiesKHR`::`maxShaderGroupStride`

- `callableShaderBindingStride` must be less than or equal to `VkPhysicalDeviceRayTracingPropertiesKHR`::`maxShaderGroupStride`

- Any shader group handle referenced by this call must have been queried from the currently bound ray tracing shader pipeline

- This command must not cause a shader call instruction to be executed from a shader invocation with a recursion depth greater than the value of `maxRecursionDepth` used to create the bound ray tracing pipeline.

- If `buffer` is non-sparse then it must be bound completely and contiguously to a single `VkDeviceMemory` object

- `buffer` must have been created with the `VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT` bit set

- `offset` must be a multiple of `4`

- `commandBuffer` must not be a protected command buffer

- (`offset` + `sizeof`(`VkTraceRaysIndirectCommandKHR`)) must be less than or equal to the size of `buffer`

- the `VkPhysicalDeviceRayTracingFeaturesKHR`→`rayTracingIndirectTraceRays` feature must be enabled

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pRaygenShaderBindingTable` must be a valid pointer to a valid VkStridedBufferRegionKHR structure

- `pMissShaderBindingTable` must be a valid pointer to a valid VkStridedBufferRegionKHR structure

- `pHitShaderBindingTable` must be a valid pointer to a valid VkStridedBufferRegionKHR structure

- `pCallableShaderBindingTable` must be a valid pointer to a valid VkStridedBufferRegionKHR structure

- `buffer` must be a valid VkBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support compute operations

- This command must only be called outside of a render pass instance

- Both of `buffer`, and `commandBuffer` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Compute |

The `VkTraceRaysIndirectCommandKHR` structure is defined as:

    typedef struct VkTraceRaysIndirectCommandKHR {
        uint32_t    width;
        uint32_t    height;
        uint32_t    depth;
    } VkTraceRaysIndirectCommandKHR;

- `width` is the width of the ray trace query dimensions.

- `height` is height of the ray trace query dimensions.

- `depth` is depth of the ray trace query dimensions.

The members of `VkTraceRaysIndirectCommandKHR` have the same meaning as the similarly named parameters of vkCmdTraceRaysKHR.

Valid Usage

- `width` must be less than or equal to `VkPhysicalDeviceLimits`::`maxComputeWorkGroupCount`[0]

- `height` must be less than or equal to `VkPhysicalDeviceLimits`::`maxComputeWorkGroupCount`[1]

- `depth` must be less than or equal to `VkPhysicalDeviceLimits`::`maxComputeWorkGroupCount`[2]

### 35.3. Shader Binding Table

A shader binding table is a resource which establishes the relationship between the ray tracing pipeline and the acceleration structures that were built for the ray tracing query. It indicates the shaders that operate on each geometry in an acceleration structure. In addition, it contains the resources accessed by each shader, including indices of textures and constants. The application allocates and manages shader binding tables as VkBuffer objects.

Each entry in the shader binding table consists of `shaderGroupHandleSize` bytes of data as queried by vkGetRayTracingShaderGroupHandlesKHR to refer to the shader that it invokes. The remainder of the data specified by the stride is application-visible data that can be referenced by a `ShaderRecordBufferKHR` block in the shader.

The shader binding tables to use in a ray tracing query are passed to vkCmdTraceRaysKHR. Shader binding tables are read-only in shaders that are executing on the ray tracing pipeline.

#### 35.3.1. Indexing Rules

In order to execute the correct shaders and access the correct resources during a ray tracing dispatch, the implementation must be able to locate shader binding table entries at various stages of execution. This is accomplished by defining a set of indexing rules that compute shader binding table record positions relative to the buffer’s base address in memory. The application must organize the contents of the shader binding table’s memory in a way that application of the indexing rules will lead to correct records.

##### Ray Generation Shaders

Only one ray generation shader is executed per ray tracing dispatch. Its location is passed into vkCmdTraceRaysKHR using the `pRaygenShaderBindingTable`::`buffer` and `pRaygenShaderBindingTable`::`offset` parameters — there is no indexing. `pRaygenShaderBindingTable`::`stride` is unused.

For vkCmdTraceRaysNV, the offset and stride come from direct parameters, so the buffer and offset come from `raygenShaderBindingBuffer` and `raygenShaderBindingOffset`

All data accessed must be less than `pRaygenShaderBindingTable`::`size` bytes from the base offset.

##### Hit Shaders

The base for the computation of intersection, any-hit and closest hit shader locations is the `instanceShaderBindingTableRecordOffset` value stored with each instance of a top-level acceleration structure. This value determines the beginning of the shader binding table records for a given instance. Each geometry in the instance must map to at least one hit program record.

In the following rule, geometryIndex refers to the location of the geometry within the instance. This index is available to ray shaders via the `RayGeometryIndexKHR` built-in.

The `sbtRecordStride` and `sbtRecordOffset` values are passed in as parameters to `traceNV`() or `traceRayEXT`() calls made in the shaders. See Section 8.19 (Ray Tracing Functions) of the OpenGL Shading Language Specification for more details. In SPIR-V, these correspond to the `SBTOffset` and `SBTStride` parameters to the `OpTraceRayKHR` instruction.

The result of this computation is then added to `pHitShaderBindingTable`::`offset` or `hitShaderBindingOffset` , a base offset passed to vkCmdTraceRaysKHR or vkCmdTraceRaysNV respectively .

The complete rule to compute a hit shader binding table record address in the `pHitShaderBindingTable`::`buffer` is:

  `pHitShaderBindingTable`::`offset` + `pHitShaderBindingTable`::`stride` × ( `instanceShaderBindingTableRecordOffset` + geometryIndex × `sbtRecordStride` + `sbtRecordOffset` )

All data accessed must be less than `pHitShaderBindingTable`::`size` bytes from the base offset.

For vkCmdTraceRaysNV, the offset and stride come from direct parameters, so the full rule is equivalently:

  `hitShaderBindingOffset` + `hitShaderBindingStride` × ( `instanceShaderBindingTableRecordOffset` + geometryIndex × `sbtRecordStride` + `sbtRecordOffset` )

##### Miss Shaders

A miss shader is executed whenever a ray query fails to find an intersection for the given scene geometry. Multiple miss shaders may be executed throughout a ray tracing dispatch.

The base for the computation of miss shader locations is `pMissShaderBindingTable`::`offset`, a base offset passed into vkCmdTraceRaysKHR.

The `missIndex` value is passed in as a parameter to `traceNV`() or `traceRayEXT`() calls made in the shaders. See Section 8.19 (Ray Tracing Functions) of the OpenGL Shading Language Specification for more details. In SPIR-V, this corresponds to the `MissIndex` parameter to the `OpTraceRayKHR` instruction.

The complete rule to compute a miss shader binding table record address in the `pMissShaderBindingTable`::`buffer` is:

  `pMissShaderBindingTable`::`offset` + `pMissShaderBindingTable`::`stride` × `missIndex`

All data accessed must be less than `pMissShaderBindingTable`::`size` bytes from the base offset.

For vkCmdTraceRaysNV, the offset and stride come from direct parameters, so the full rule is equivalently:

  `missShaderBindingOffset` + `missShaderBindingStride` × `missIndex`

##### Callable Shaders

A callable shader is executed when requested by a ray tracing shader. Multiple callable shaders may be executed throughout a ray tracing dispatch.

The base for the computation of callable shader locations is `pCallableShaderBindingTable`::`offset`, a base offset passed into vkCmdTraceRaysKHR.

The `sbtRecordIndex` value is passed in as a parameter to `executeCallableNV`() or `executeCallableEXT`() calls made in the shaders. See Section 8.19 (Ray Tracing Functions) of the OpenGL Shading Language Specification for more details. In SPIR-V, this corresponds to the `SBTIndex` parameter to the `OpExecuteCallableKHR` instruction.

The complete rule to compute a callable shader binding table record address in the `pCallableShaderBindingTable`::`buffer` is:

  `pCallableShaderBindingTable`::`offset` + `pCallableShaderBindingTable`::`stride` × `sbtRecordIndex`

All data accessed must be less than `pCallableShaderBindingTable`::`size` bytes from the base offset.

For vkCmdTraceRaysNV, the offset and stride come from direct parameters, so the full rule is equivalently:

  `callableShaderBindingOffset` + `callableShaderBindingStride` × `sbtRecordIndex`

### 35.4. Acceleration Structures

Acceleration structures are data structures used by the implementation to efficiently manage scene geometry as it is traversed during a ray tracing query. The application is responsible for managing acceleration structure objects (see Acceleration Structures), including allocation, destruction, executing builds or updates, and synchronizing resources used during ray tracing queries.

There are two types of acceleration structures, top level acceleration structures and bottom level acceleration structures.

Figure 25. Acceleration Structure
Caption

The diagram shows the relationship between top and bottom level acceleration structures.

#### 35.4.1. Geometry

Geometries refer to a triangle or axis-aligned bounding box.

#### 35.4.2. Inactive Primitives and Instances

Acceleration structures allow the use of particular input values to signal inactive primitives or instances.

An inactive triangle is one for which the first (X) component of each vertex is NaN. If any other vertex component is NaN, and the first is not, the behavior is undefined. If the vertex format does not have a NaN representation, then all triangles are considered active.

An inactive instance is one whose acceleration structure handle is NULL.

An inactive AABB is one for which the minimum X coordinate is NaN. If any other component is NaN, and the first is not, the behavior is undefined.

In the above definitions, "NaN" refers to any type of NaN. Signaling, non-signaling, quiet, loud, or otherwise.

An inactive object is considered invisible to all rays, and should not be represented in the acceleration structure. Implementations should ensure that the presence of inactive objects does not seriously degrade ray tracing performance.

Inactive objects are counted in the auto-generated index sequences which are provided to shaders via `InstanceId` and `PrimitiveId` SPIR-V decorations. This allows objects in the scene to change freely between the active and inactive states, without affecting the layout of any arrays which are being indexed using the ID values.

Any transition between the active and inactive states requires a full acceleration structure rebuild. An update is not sufficient. If an inactive object is made active by an update operation (or vice versa), the results are undefined.

#### 35.4.3. Top Level Acceleration Structures

Opaque acceleration structure for an array of instances. The descriptor referencing this is the starting point for tracing

#### 35.4.4. Bottom Level Acceleration Structures

Opaque acceleration structure for an array of geometries.

#### 35.4.5. Building Acceleration Structures

To build an acceleration structure call:

    void vkCmdBuildAccelerationStructureNV(
        VkCommandBuffer                             commandBuffer,
        const VkAccelerationStructureInfoNV*        pInfo,
        VkBuffer                                    instanceData,
        VkDeviceSize                                instanceOffset,
        VkBool32                                    update,
        VkAccelerationStructureKHR                  dst,
        VkAccelerationStructureKHR                  src,
        VkBuffer                                    scratch,
        VkDeviceSize                                scratchOffset);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `pInfo` contains the shared information for the acceleration structure’s structure.

- `instanceData` is the buffer containing an array of VkAccelerationStructureInstanceKHR structures defining acceleration structures. This parameter must be `NULL` for bottom level acceleration structures.

- `instanceOffset` is the offset in bytes (relative to the start of `instanceData`) at which the instance data is located.

- `update` specifies whether to update the `dst` acceleration structure with the data in `src`.

- `dst` is a pointer to the target acceleration structure for the build.

- `src` is a pointer to an existing acceleration structure that is to be used to update the `dst` acceleration structure.

- `scratch` is the VkBuffer that will be used as scratch memory for the build.

- `scratchOffset` is the offset in bytes relative to the start of `scratch` that will be used as a scratch memory.

Valid Usage

- `geometryCount` must be less than or equal to VkPhysicalDeviceRayTracingPropertiesNV::`maxGeometryCount`

- `dst` must have been created with compatible VkAccelerationStructureInfoNV where VkAccelerationStructureInfoNV::`type` and VkAccelerationStructureInfoNV::`flags` are identical, VkAccelerationStructureInfoNV::`instanceCount` and VkAccelerationStructureInfoNV::`geometryCount` for `dst` are greater than or equal to the build size and each geometry in VkAccelerationStructureInfoNV::`pGeometries` for `dst` has greater than or equal to the number of vertices, indices, and AABBs.

- If `update` is `VK_TRUE`, `src` must not be VK_NULL_HANDLE

- If `update` is `VK_TRUE`, `src` must have been built before with `VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_UPDATE_BIT_NV` set in VkAccelerationStructureInfoNV::`flags`

- If `update` is `VK_FALSE`, the `size` member of the VkMemoryRequirements structure returned from a call to vkGetAccelerationStructureMemoryRequirementsNV with VkAccelerationStructureMemoryRequirementsInfoNV::`accelerationStructure` set to `dst` and VkAccelerationStructureMemoryRequirementsInfoNV::`type` set to `VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_BUILD_SCRATCH_NV` must be less than or equal to the size of `scratch` minus `scratchOffset`

- If `update` is `VK_TRUE`, the `size` member of the VkMemoryRequirements structure returned from a call to vkGetAccelerationStructureMemoryRequirementsNV with VkAccelerationStructureMemoryRequirementsInfoNV::`accelerationStructure` set to `dst` and VkAccelerationStructureMemoryRequirementsInfoNV::`type` set to `VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_UPDATE_SCRATCH_NV` must be less than or equal to the size of `scratch` minus `scratchOffset`

- `scratch` must have been created with `VK_BUFFER_USAGE_RAY_TRACING_BIT_NV` usage flag

- If `instanceData` is not VK_NULL_HANDLE, `instanceData` must have been created with `VK_BUFFER_USAGE_RAY_TRACING_BIT_NV` usage flag

- If `update` is `VK_TRUE`, then objects that were previously active must not be made inactive as per Inactive Primitives and Instances

- If `update` is `VK_TRUE`, then objects that were previously inactive must not be made active as per Inactive Primitives and Instances

- If `update` is `VK_TRUE`, the `src` and `dst` objects must either be the same object or not have any memory aliasing

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pInfo` must be a valid pointer to a valid VkAccelerationStructureInfoNV structure

- If `instanceData` is not VK_NULL_HANDLE, `instanceData` must be a valid VkBuffer handle

- `dst` must be a valid VkAccelerationStructureKHR handle

- If `src` is not VK_NULL_HANDLE, `src` must be a valid VkAccelerationStructureKHR handle

- `scratch` must be a valid VkBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support compute operations

- This command must only be called outside of a render pass instance

- Each of `commandBuffer`, `dst`, `instanceData`, `scratch`, and `src` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Compute |

To build acceleration structures call:

    void vkCmdBuildAccelerationStructureKHR(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    infoCount,
        const VkAccelerationStructureBuildGeometryInfoKHR* pInfos,
        const VkAccelerationStructureBuildOffsetInfoKHR* const* ppOffsetInfos);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `infoCount` is the number of acceleration structures to build. It specifies the number of the `pInfos` structures and `ppOffsetInfos` pointers that must be provided.

- `pInfos` is an array of `infoCount` VkAccelerationStructureBuildGeometryInfoKHR structures defining the geometry used to build each acceleration structure.

- `ppOffsetInfos` is an array of `infoCount` pointers to arrays of VkAccelerationStructureBuildOffsetInfoKHR structures. Each `ppOffsetInfos`[i] is an array of `pInfos`[i]→`geometryCount` VkAccelerationStructureBuildOffsetInfoKHR structures defining dynamic offsets to the addresses where geometry data is stored, as defined by `pInfos`[i].

The `vkCmdBuildAccelerationStructureKHR` command provides the ability to initiate multiple acceleration structures builds, however there is no ordering or synchronization implied between any of the individual acceleration structure builds.

| Note This means that an application cannot build a top-level acceleration structure in the same vkCmdBuildAccelerationStructureKHR call as the associated bottom-level or instance acceleration structures are being built. There also cannot be any memory aliasing between any acceleration structure memories or scratch memories being used by any of the builds.

Valid Usage

- `pOffsetInfos`[i] must be a valid pointer to an array of `pInfos`[i]→`geometryCount` `VkAccelerationStructureBuildOffsetInfoKHR` structures

- Each `pInfos`[i].`srcAccelerationStructure` must not refer to the same acceleration structure as any `pInfos`[i].`dstAccelerationStructure` that is provided to the same build command unless it is identical for an update

- For each `pInfos`[i], `dstAccelerationStructure` must have been created with compatible VkAccelerationStructureCreateInfoKHR where VkAccelerationStructureCreateInfoKHR::`type` and VkAccelerationStructureCreateInfoKHR::`flags` are identical to VkAccelerationStructureBuildGeometryInfoKHR::`type` and VkAccelerationStructureBuildGeometryInfoKHR::`flags` respectively, VkAccelerationStructureBuildGeometryInfoKHR::`geometryCount` for `dstAccelerationStructure` are greater than or equal to the build size, and each geometry in VkAccelerationStructureBuildGeometryInfoKHR::`ppGeometries` for `dstAccelerationStructure` has greater than or equal to the number of vertices, indices, and AABBs, VkAccelerationStructureGeometryTrianglesDataKHR::`transformData` is both 0 or both non-zero, and all other parameters are the same.

- For each `pInfos`[i], if `update` is `VK_TRUE`, then objects that were previously active for that acceleration structure must not be made inactive as per Inactive Primitives and Instances

- For each `pInfos`[i], if `update` is `VK_TRUE`, then objects that were previously inactive for that acceleration structure must not be made active as per Inactive Primitives and Instances

- Any acceleration structure instance in any top level build in this command must not reference any bottom level acceleration structure built by this command

- There must not be any memory aliasing between the scratch memories that are provided in all the `pInfos`[i].`scratchData` memories for the acceleration structure builds

- There must not be any memory aliasing between memory bound to any top level, bottom level, or instance acceleration structure accessed by this command

- If `update` is `VK_FALSE`, all addresses between `pInfos`[i].`scratchData` and `pInfos`[i].`scratchData` + N - 1 must be in the buffer device address range of the same buffer, where N is given by the `size` member of the VkMemoryRequirements structure returned from a call to vkGetAccelerationStructureMemoryRequirementsKHR with VkAccelerationStructureMemoryRequirementsInfoKHR::`accelerationStructure` set to `pInfos`[i].`dstAccelerationStructure` and VkAccelerationStructureMemoryRequirementsInfoKHR::`type` set to `VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_BUILD_SCRATCH_KHR`

- If `update` is `VK_TRUE`, all addresses between `pInfos`[i].`scratchData` and `pInfos`[i].`scratchData` + N - 1 must be in the buffer device address range of the same buffer, where N is given by the `size` member of the VkMemoryRequirements structure returned from a call to vkGetAccelerationStructureMemoryRequirementsKHR with VkAccelerationStructureMemoryRequirementsInfoKHR::`accelerationStructure` set to `pInfos`[i].`dstAccelerationStructure` and VkAccelerationStructureMemoryRequirementsInfoKHR::`type` set to `VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_UPDATE_SCRATCH_KHR`

- The buffer from which the buffer device address `pInfos`[i].`scratchData` is queried must have been created with `VK_BUFFER_USAGE_RAY_TRACING_BIT_KHR` usage flag

- All VkDeviceOrHostAddressKHR or VkDeviceOrHostAddressConstKHR referenced by this command must contain valid device addresses

- All `VkAccelerationStructureKHR` objects referenced by this command must be bound to device memory

- The VkDeferredOperationInfoKHR structure must not be included in the `pNext` chain of any of the provided VkAccelerationStructureBuildGeometryInfoKHR structures.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pInfos` must be a valid pointer to an array of `infoCount` valid VkAccelerationStructureBuildGeometryInfoKHR structures

- `ppOffsetInfos` must be a valid pointer to an array of `infoCount` VkAccelerationStructureBuildOffsetInfoKHR structures

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support compute operations

- This command must only be called outside of a render pass instance

- `infoCount` must be greater than `0`

Host Synchronization

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Compute |

To build an acceleration structure with some parameters sourced on the device call:

    void vkCmdBuildAccelerationStructureIndirectKHR(
        VkCommandBuffer                             commandBuffer,
        const VkAccelerationStructureBuildGeometryInfoKHR* pInfo,
        VkBuffer                                    indirectBuffer,
        VkDeviceSize                                indirectOffset,
        uint32_t                                    indirectStride);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `pInfo` is a pointer to a VkAccelerationStructureBuildGeometryInfoKHR structure defining the geometry used to build the acceleration structure.

- `indirectBuffer` is the VkBuffer containing `pInfo->pname`:geometryCount VkAccelerationStructureBuildOffsetInfoKHR structures defining dynamic offsets to the addresses where geometry data is stored, as defined by `pInfo`.

- `indirectOffset` is the byte offset into `indirectBuffer` where offset parameters begin.

- `stride` is the byte stride between successive sets of offset parameters.

Valid Usage

- All VkDeviceOrHostAddressKHR or VkDeviceOrHostAddressConstKHR referenced by this command must contain valid device addresses

- All `VkAccelerationStructureKHR` objects referenced by this command must be bound to device memory

- The `VkPhysicalDeviceRayTracingFeaturesKHR`→`rayTracingIndirectAccelerationStructureBuild` feature must be enabled

- The VkDeferredOperationInfoKHR structure must not be included in the `pNext` chain of any of the provided VkAccelerationStructureBuildGeometryInfoKHR structures.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pInfo` must be a valid pointer to a valid VkAccelerationStructureBuildGeometryInfoKHR structure

- `indirectBuffer` must be a valid VkBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support compute operations

- This command must only be called outside of a render pass instance

- Both of `commandBuffer`, and `indirectBuffer` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Compute |

The `VkAccelerationStructureBuildGeometryInfoKHR` structure is defined as:

    typedef struct VkAccelerationStructureBuildGeometryInfoKHR {
        VkStructureType                                     sType;
        const void*                                         pNext;
        VkAccelerationStructureTypeKHR                      type;
        VkBuildAccelerationStructureFlagsKHR                flags;
        VkBool32                                            update;
        VkAccelerationStructureKHR                          srcAccelerationStructure;
        VkAccelerationStructureKHR                          dstAccelerationStructure;
        VkBool32                                            geometryArrayOfPointers;
        uint32_t                                            geometryCount;
        const VkAccelerationStructureGeometryKHR* const*    ppGeometries;
        VkDeviceOrHostAddressKHR                            scratchData;
    } VkAccelerationStructureBuildGeometryInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `type` is a VkAccelerationStructureTypeKHR value specifying the type of acceleration structure being built.

- `flags` is a bitmask of VkBuildAccelerationStructureFlagBitsKHR specifying additional parameters of the acceleration structure.

- `update` specifies whether to update `dstAccelerationStructure` with the data in `srcAccelerationStructure` or not.

- `srcAccelerationStructure` points to an existing acceleration structure that is to be used to update the `dst` acceleration structure when `update` is `VK_TRUE`.

- `dstAccelerationStructure` points to the target acceleration structure for the build.

- `geometryArrayOfPointers` specifies whether `ppGeometries` is used as a pointer to an array of pointers or a pointer to a pointer to an array.

- `geometryCount` specifies the number of geometries that will be built into `dstAccelerationStructure`.

- `ppGeometries` is either a pointer to an array of pointers to VkAccelerationStructureGeometryKHR structures if `geometryArrayOfPointers` is `VK_TRUE`, or a pointer to a pointer to an array of VkAccelerationStructureGeometryKHR structures if it’s `VK_FALSE`. Each element of the array describes the data used to build each acceleration structure geometry.

- `scratchData` is the device or host address to memory that will be used as scratch memory for the build.

| Note Elements of `ppGeometries` are accessed as follows, based on `geometryArrayOfPointers`:
    if (geometryArrayOfPointers) {
        use *(ppGeometries[i]);
    } else {
        use (*ppGeometries)[i];
    }

Valid Usage

- If `update` is `VK_TRUE`, `srcAccelerationStructure` must not be VK_NULL_HANDLE

- If `update` is `VK_TRUE`, `srcAccelerationStructure` must have been built before with `VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_UPDATE_BIT_KHR` set in VkAccelerationStructureBuildGeometryInfoKHR::`flags`

- `scratchData` must have been created with `VK_BUFFER_USAGE_RAY_TRACING_BIT_KHR` usage flag

- If `update` is enam:VK_TRUE, the `srcAccelerationStructure` and `dstAccelerationStructure` objects must either be the same object or not have any memory aliasing

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_BUILD_GEOMETRY_INFO_KHR`

- `pNext` must be `NULL` or a pointer to a valid instance of VkDeferredOperationInfoKHR

- The `sType` value of each struct in the `pNext` chain must be unique

- `type` must be a valid VkAccelerationStructureTypeKHR value

- `flags` must be a valid combination of VkBuildAccelerationStructureFlagBitsKHR values

- If `srcAccelerationStructure` is not VK_NULL_HANDLE, `srcAccelerationStructure` must be a valid VkAccelerationStructureKHR handle

- `dstAccelerationStructure` must be a valid VkAccelerationStructureKHR handle

- `scratchData` must be a valid VkDeviceOrHostAddressKHR union

- Both of `dstAccelerationStructure`, and `srcAccelerationStructure` that are valid handles of non-ignored parameters must have been created, allocated, or retrieved from the same VkDevice

The `VkDeviceOrHostAddressKHR` union is defined as:

    typedef union VkDeviceOrHostAddressKHR {
        VkDeviceAddress    deviceAddress;
        void*              hostAddress;
    } VkDeviceOrHostAddressKHR;

- `deviceAddress` is a buffer device address as returned by the vkGetBufferDeviceAddressKHR command.

- `hostAddress` is a host memory address.

The `VkDeviceOrHostAddressConstKHR` union is defined as:

    typedef union VkDeviceOrHostAddressConstKHR {
        VkDeviceAddress    deviceAddress;
        const void*        hostAddress;
    } VkDeviceOrHostAddressConstKHR;

- `deviceAddress` is a buffer device address as returned by the vkGetBufferDeviceAddressKHR command.

- `hostAddress` is a const host memory address.

The `VkAccelerationStructureGeometryKHR` structure is defined as:

    typedef struct VkAccelerationStructureGeometryKHR {
        VkStructureType                           sType;
        const void*                               pNext;
        VkGeometryTypeKHR                         geometryType;
        VkAccelerationStructureGeometryDataKHR    geometry;
        VkGeometryFlagsKHR                        flags;
    } VkAccelerationStructureGeometryKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `geometryType` describes which type of geometry this `VkAccelerationStructureGeometryKHR` refers to.

- `geometry` is a VkAccelerationStructureGeometryDataKHR union describing the geometry data for the relevant geometry type.

- `flags` is a bitmask of VkGeometryFlagBitsKHR values describing additional properties of how the geometry should be built.

Valid Usage

- If `geometryType` is `VK_GEOMETRY_TYPE_AABBS_KHR`, the `aabbs` member of `geometry` must be a valid VkAccelerationStructureGeometryAabbsDataKHR structure

- If `geometryType` is `VK_GEOMETRY_TYPE_TRIANGLES_KHR`, the `triangles` member of `geometry` must be a valid VkAccelerationStructureGeometryTrianglesDataKHR structure

- If `geometryType` is `VK_GEOMETRY_TYPE_INSTANCES_KHR`, the `instances` member of `geometry` must be a valid VkAccelerationStructureGeometryInstancesDataKHR structure

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_GEOMETRY_KHR`

- `pNext` must be `NULL`

- `geometryType` must be a valid VkGeometryTypeKHR value

- `geometry` must be a valid VkAccelerationStructureGeometryDataKHR union

- `flags` must be a valid combination of VkGeometryFlagBitsKHR values

The `VkAccelerationStructureGeometryDataKHR` union is defined as:

    typedef union VkAccelerationStructureGeometryDataKHR {
        VkAccelerationStructureGeometryTrianglesDataKHR    triangles;
        VkAccelerationStructureGeometryAabbsDataKHR        aabbs;
        VkAccelerationStructureGeometryInstancesDataKHR    instances;
    } VkAccelerationStructureGeometryDataKHR;

- `triangles` is a VkAccelerationStructureGeometryTrianglesDataKHR structure.

- `aabbs` is a VkAccelerationStructureGeometryAabbsDataKHR struture.

- `instances` is a VkAccelerationStructureGeometryInstancesDataKHR structure.

Valid Usage (Implicit)

- `triangles` must be a valid VkAccelerationStructureGeometryTrianglesDataKHR structure

- `aabbs` must be a valid VkAccelerationStructureGeometryAabbsDataKHR structure

- `instances` must be a valid VkAccelerationStructureGeometryInstancesDataKHR structure

The `VkAccelerationStructureGeometryTrianglesDataKHR` structure is defined as:

    typedef struct VkAccelerationStructureGeometryTrianglesDataKHR {
        VkStructureType                  sType;
        const void*                      pNext;
        VkFormat                         vertexFormat;
        VkDeviceOrHostAddressConstKHR    vertexData;
        VkDeviceSize                     vertexStride;
        VkIndexType                      indexType;
        VkDeviceOrHostAddressConstKHR    indexData;
        VkDeviceOrHostAddressConstKHR    transformData;
    } VkAccelerationStructureGeometryTrianglesDataKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `vertexFormat` is the VkFormat of each vertex element.

- `vertexData` is a device or host address to memory containing vertex data for this geometry.

- `vertexStride` is the stride in bytes between each vertex.

- `indexType` is the VkIndexType of each index element.

- `indexData` is the device or host address to memory containing index data for this geometry.

- `transformData` is a device or host address to memory containing an optional reference to a VkTransformMatrixKHR structure defining a transformation that should be applied to vertices in this geometry.

Valid Usage
Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_GEOMETRY_TRIANGLES_DATA_KHR`

- `pNext` must be `NULL`

- `vertexFormat` must be a valid VkFormat value

- `vertexData` must be a valid VkDeviceOrHostAddressConstKHR union

- `indexType` must be a valid VkIndexType value

- If `indexData` is not `0`, `indexData` must be a valid VkDeviceOrHostAddressConstKHR union

- If `transformData` is not `0`, `transformData` must be a valid VkDeviceOrHostAddressConstKHR union

The `VkTransformMatrixKHR` structure is defined as:

    typedef struct VkTransformMatrixKHR {
        float    matrix[3][4];
    } VkTransformMatrixKHR;

or the equivalent

    typedef VkTransformMatrixKHR VkTransformMatrixNV;

- `matrix` is a 3x4 row-major affine transformation matrix.

The `VkAccelerationStructureGeometryAabbsDataKHR` structure is defined as:

    typedef struct VkAccelerationStructureGeometryAabbsDataKHR {
        VkStructureType                  sType;
        const void*                      pNext;
        VkDeviceOrHostAddressConstKHR    data;
        VkDeviceSize                     stride;
    } VkAccelerationStructureGeometryAabbsDataKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `data` is a device or host address to memory containing VkAabbPositionsKHR structures containing position data for each axis-aligned bounding box in the geometry.

- `stride` is the stride in bytes between each entry in `data`.

Valid Usage

- `data` must be aligned to `8` bytes

- `stride` must be a multiple of `8`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_GEOMETRY_AABBS_DATA_KHR`

- `pNext` must be `NULL`

- `data` must be a valid VkDeviceOrHostAddressConstKHR union

An axis-aligned bounding box positions are defined by the structure:

    typedef struct VkAabbPositionsKHR {
        float    minX;
        float    minY;
        float    minZ;
        float    maxX;
        float    maxY;
        float    maxZ;
    } VkAabbPositionsKHR;

or the equivalent

    typedef VkAabbPositionsKHR VkAabbPositionsNV;

- `minX` is the x position of one opposing corner of a bounding box.

- `minY` is the y position of one opposing corner of a bounding box.

- `minZ` is the z position of one opposing corner of a bounding box.

- `maxX` is the x position of the other opposing corner of a bounding box.

- `maxY` is the y position of the other opposing corner of a bounding box.

- `maxZ` is the z position of the other opposing corner of a bounding box.

Valid Usage

- `minX` must be less than or equal to `maxX`

- `minY` must be less than or equal to `maxY`

- `minZ` must be less than or equal to `maxZ`

The `VkAccelerationStructureGeometryInstancesDataKHR` structure is defined as:

    typedef struct VkAccelerationStructureGeometryInstancesDataKHR {
        VkStructureType                  sType;
        const void*                      pNext;
        VkBool32                         arrayOfPointers;
        VkDeviceOrHostAddressConstKHR    data;
    } VkAccelerationStructureGeometryInstancesDataKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `arrayOfPointers` specifies whether `data` is used as an array of addresses or just an array.

- `data` is either the address of an array of device or host addresses referencing individual VkAccelerationStructureInstanceKHR structures if `arrayOfPointers` is `VK_TRUE`, or the address of an array of VkAccelerationStructureInstanceKHR structures.

Valid Usage

- `data` must be aligned to `16` bytes

- If `arrayOfPointers` is true, each pointer must be aligned to `16` bytes

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_GEOMETRY_INSTANCES_DATA_KHR`

- `pNext` must be `NULL`

- `data` must be a valid VkDeviceOrHostAddressConstKHR union

Acceleration structure instances can be built into top-level acceleration structures. Each acceleration structure instance is a separate entry in the top-level acceleration structure which includes all the geometry of a bottom-level acceleration structure at a transformed location. Multiple instances can point to the same bottom level acceleration structure.

An acceleration structure instance is defined by the structure:

    typedef struct VkAccelerationStructureInstanceKHR {
        VkTransformMatrixKHR          transform;
        uint32_t                      instanceCustomIndex:24;
        uint32_t                      mask:8;
        uint32_t                      instanceShaderBindingTableRecordOffset:24;
        VkGeometryInstanceFlagsKHR    flags:8;
        uint64_t                      accelerationStructureReference;
    } VkAccelerationStructureInstanceKHR;

or the equivalent

    typedef VkAccelerationStructureInstanceKHR VkAccelerationStructureInstanceNV;

- `transform` is a VkTransformMatrixKHR structure describing a transformation to be applied to the acceleration structure.

- `instanceCustomIndex` a 24-bit user-specified index value accessible to ray shaders in the `InstanceCustomIndexKHR` built-in.

- `mask` is an 8-bit visibility mask for the geometry. The instance may only be hit if `rayMask & instance.mask != 0`

- `instanceShaderBindingTableRecordOffset` is a 24-bit offset used in calculating the hit shader binding table index.

- `flags` is an 8-bit mask of VkGeometryInstanceFlagBitsKHR values to apply to this instance.

- `accelerationStructureReference` is either:

  - a device address containing the value obtained from vkGetAccelerationStructureDeviceAddressKHR or vkGetAccelerationStructureHandleNV (used by device operations which reference acceleration structures) or,

  - a VkAccelerationStructureKHR object (used by host operations which reference acceleration structures).

The C language spec does not define the ordering of bit-fields, but in practice, this struct produces the correct layout with existing compilers. The intended bit pattern is for the following:

- `instanceCustomIndex` and `mask` occupy the same memory as if a single `int32_t` was specified in their place

  - `instanceCustomIndex` occupies the 24 least significant bits of that memory

  - `mask` occupies the 8 most significant bits of that memory

- `instanceShaderBindingTableRecordOffset` and `flags` occupy the same memory as if a single `int32_t` was specified in their place

  - `instanceShaderBindingTableRecordOffset` occupies the 24 least significant bits of that memory

  - `flags` occupies the 8 most significant bits of that memory

If a compiler produces code that diverges from that pattern, applications must employ another method to set values according to the correct bit pattern.

Valid Usage
Valid Usage (Implicit)

- `flags` must be a valid combination of VkGeometryInstanceFlagBitsKHR values

Possible values of `flags` in the instance modifying the behavior of that instance are:,

    typedef enum VkGeometryInstanceFlagBitsKHR {
        VK_GEOMETRY_INSTANCE_TRIANGLE_FACING_CULL_DISABLE_BIT_KHR = 0x00000001,
        VK_GEOMETRY_INSTANCE_TRIANGLE_FRONT_COUNTERCLOCKWISE_BIT_KHR = 0x00000002,
        VK_GEOMETRY_INSTANCE_FORCE_OPAQUE_BIT_KHR = 0x00000004,
        VK_GEOMETRY_INSTANCE_FORCE_NO_OPAQUE_BIT_KHR = 0x00000008,
        VK_GEOMETRY_INSTANCE_TRIANGLE_CULL_DISABLE_BIT_NV = VK_GEOMETRY_INSTANCE_TRIANGLE_FACING_CULL_DISABLE_BIT_KHR,
        VK_GEOMETRY_INSTANCE_TRIANGLE_FRONT_COUNTERCLOCKWISE_BIT_NV = VK_GEOMETRY_INSTANCE_TRIANGLE_FRONT_COUNTERCLOCKWISE_BIT_KHR,
        VK_GEOMETRY_INSTANCE_FORCE_OPAQUE_BIT_NV = VK_GEOMETRY_INSTANCE_FORCE_OPAQUE_BIT_KHR,
        VK_GEOMETRY_INSTANCE_FORCE_NO_OPAQUE_BIT_NV = VK_GEOMETRY_INSTANCE_FORCE_NO_OPAQUE_BIT_KHR,
        VK_GEOMETRY_INSTANCE_FLAG_BITS_MAX_ENUM_KHR = 0x7FFFFFFF
    } VkGeometryInstanceFlagBitsKHR;

or the equivalent

    typedef VkGeometryInstanceFlagBitsKHR VkGeometryInstanceFlagBitsNV;

- `VK_GEOMETRY_INSTANCE_TRIANGLE_FACING_CULL_DISABLE_BIT_KHR` disables face culling for this instance.

- `VK_GEOMETRY_INSTANCE_TRIANGLE_FRONT_COUNTERCLOCKWISE_BIT_KHR` indicates that the front face of the triangle for culling purposes is the face that is counter clockwise in object space relative to the ray origin. Because the facing is determined in object space, an instance transform matrix does not change the winding, but a geometry transform does.

- `VK_GEOMETRY_INSTANCE_FORCE_OPAQUE_BIT_KHR` causes this instance to act as though `VK_GEOMETRY_OPAQUE_BIT_KHR` were specified on all geometries referenced by this instance. This behavior can be overridden by the SPIR-V `NoOpaqueKHR` ray flag.

- `VK_GEOMETRY_INSTANCE_FORCE_NO_OPAQUE_BIT_KHR` causes this instance to act as though `VK_GEOMETRY_OPAQUE_BIT_KHR` were not specified on all geometries referenced by this instance. This behavior can be overridden by the SPIR-V `OpaqueKHR` ray flag.

`VK_GEOMETRY_INSTANCE_FORCE_NO_OPAQUE_BIT_KHR` and `VK_GEOMETRY_INSTANCE_FORCE_OPAQUE_BIT_KHR` must not be used in the same flag.

    typedef VkFlags VkGeometryInstanceFlagsKHR;

or the equivalent

    typedef VkGeometryInstanceFlagsKHR VkGeometryInstanceFlagsNV;

`VkGeometryInstanceFlagsKHR` is a bitmask type for setting a mask of zero or more VkGeometryInstanceFlagBitsKHR.

`VkAccelerationStructureBuildOffsetInfoKHR` is defined as:

    typedef struct VkAccelerationStructureBuildOffsetInfoKHR {
        uint32_t    primitiveCount;
        uint32_t    primitiveOffset;
        uint32_t    firstVertex;
        uint32_t    transformOffset;
    } VkAccelerationStructureBuildOffsetInfoKHR;

- `primitiveCount` defines the number of primitives for a corresponding acceleration structure geometry.

- `primitiveOffset` defines an offset in bytes into the memory where primitive data is defined.

- `firstVertex` is the index of the first vertex to build from for triangle geometry.

- `transformOffset` defines an offset in bytes into the memory where a transform matrix is defined.

The primitive count and primitive offset are interpreted differently depending on the VkGeometryTypeKHR used:

- For geometries of type `VK_GEOMETRY_TYPE_TRIANGLES_KHR`, `primitiveCount` is the number of triangles to be built, where each triangle is treated as 3 vertices.

  - If the geometry uses indices, `primitiveCount` × 3 indices are consumed from VkAccelerationStructureGeometryTrianglesDataKHR::`indexData`, starting at an offset of `primitiveOffset`. The value of `firstVertex` is added to the index values before fetching vertices.

  - If the geometry does not use indices, `primitiveCount` × 3 vertices are consumed from VkAccelerationStructureGeometryTrianglesDataKHR::`vertexData`, starting at an offset of `primitiveOffset` + VkAccelerationStructureGeometryTrianglesDataKHR::`vertexStride` × `firstVertex`.

  - A single VkTransformMatrixKHR structure is consumed from VkAccelerationStructureGeometryTrianglesDataKHR::`transformData`, at an offset of `transformOffset`. This transformation matrix is used by all triangles.

- For geometries of type `VK_GEOMETRY_TYPE_AABBS_KHR`, `primitiveCount` is the number of axis-aligned bounding boxes. `primitiveCount` VkAabbPositionsKHR structures are consumed from VkAccelerationStructureGeometryAabbsDataKHR::`data`, starting at an offset of `primitiveOffset`.

- For geometries of type `VK_GEOMETRY_TYPE_INSTANCES_KHR`, `primitiveCount` is the number of acceleration structures. `primitiveCount` VkAccelerationStructureInstanceKHR structures are consumed from VkAccelerationStructureGeometryInstancesDataKHR::`data`, starting at an offset of `primitiveOffset`.

Valid Usage

- For geometries of type `VK_GEOMETRY_TYPE_TRIANGLES_KHR`, if the geometry uses indices, the offset `primitiveOffset` from VkAccelerationStructureGeometryTrianglesDataKHR::`indexData` must be a multiple of the element size of VkAccelerationStructureGeometryTrianglesDataKHR::`indexType`

- For geometries of type `VK_GEOMETRY_TYPE_TRIANGLES_KHR`, if the geometry doesn’t use indices, the offset `primitiveOffset` from VkAccelerationStructureGeometryTrianglesDataKHR::`vertexData` must be a multiple of the component size of VkAccelerationStructureGeometryTrianglesDataKHR::`vertexType`

- For geometries of type `VK_GEOMETRY_TYPE_TRIANGLES_KHR`, the offset `transformOffset` from VkAccelerationStructureGeometryTrianglesDataKHR::`transformData` must be a multiple of 16

- For geometries of type `VK_GEOMETRY_TYPE_AABBS_KHR`, the offset `primitiveOffset` from VkAccelerationStructureGeometryAabbsDataKHR::`data` must be a multiple of 8

- For geometries of type `VK_GEOMETRY_TYPE_INSTANCES_KHR`, the offset `primitiveOffset` from VkAccelerationStructureGeometryInstancesDataKHR::`data` must be a multiple of 16 // TODO - Almost certainly should be more here

#### 35.4.6. Copying Acceleration Structures

An additional command exists for copying acceleration structures without updating their contents. The acceleration structure object can be compacted in order to improve performance. Before copying, an application must query the size of the resulting acceleration structure.

To query acceleration structure size parameters call:

    void vkCmdWriteAccelerationStructuresPropertiesKHR(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    accelerationStructureCount,
        const VkAccelerationStructureKHR*           pAccelerationStructures,
        VkQueryType                                 queryType,
        VkQueryPool                                 queryPool,
        uint32_t                                    firstQuery);

or the equivalent command

    void vkCmdWriteAccelerationStructuresPropertiesNV(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    accelerationStructureCount,
        const VkAccelerationStructureKHR*           pAccelerationStructures,
        VkQueryType                                 queryType,
        VkQueryPool                                 queryPool,
        uint32_t                                    firstQuery);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `accelerationStructureCount` is the count of acceleration structures for which to query the property.

- `pAccelerationStructures` is a pointer to an array of existing previously built acceleration structures.

- `queryType` is a VkQueryType value specifying the type of queries managed by the pool.

- `queryPool` is the query pool that will manage the results of the query.

- `firstQuery` is the first query index within the query pool that will contain the `accelerationStructureCount` number of results.

Valid Usage

- `queryPool` must have been created with a `queryType` matching `queryType`

- The queries identified by `queryPool` and `firstQuery` must be unavailable

- All acceleration structures in `accelerationStructures` must have been built with `VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_COMPACTION_BIT_KHR` if `queryType` is `VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_KHR`

- `queryType` must be `VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_KHR` or `VK_QUERY_TYPE_ACCELERATION_STRUCTURE_SERIALIZATION_SIZE_KHR`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pAccelerationStructures` must be a valid pointer to an array of `accelerationStructureCount` valid VkAccelerationStructureKHR handles

- `queryType` must be a valid VkQueryType value

- `queryPool` must be a valid VkQueryPool handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support compute operations

- This command must only be called outside of a render pass instance

- `accelerationStructureCount` must be greater than `0`

- Each of `commandBuffer`, `queryPool`, and the elements of `pAccelerationStructures` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Compute |

To copy an acceleration structure call:

    void vkCmdCopyAccelerationStructureNV(
        VkCommandBuffer                             commandBuffer,
        VkAccelerationStructureKHR                  dst,
        VkAccelerationStructureKHR                  src,
        VkCopyAccelerationStructureModeKHR          mode);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `dst` is a pointer to the target acceleration structure for the copy.

- `src` is a pointer to the source acceleration structure for the copy.

- `mode` is a VkCopyAccelerationStructureModeKHR value specifying additional operations to perform during the copy.

Valid Usage

- `mode` must be `VK_COPY_ACCELERATION_STRUCTURE_MODE_COMPACT_KHR` or `VK_COPY_ACCELERATION_STRUCTURE_MODE_CLONE_KHR`

- `src` must have been built with `VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_COMPACTION_BIT_KHR` if `mode` is `VK_COPY_ACCELERATION_STRUCTURE_MODE_COMPACT_KHR`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `dst` must be a valid VkAccelerationStructureKHR handle

- `src` must be a valid VkAccelerationStructureKHR handle

- `mode` must be a valid VkCopyAccelerationStructureModeKHR value

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support compute operations

- This command must only be called outside of a render pass instance

- Each of `commandBuffer`, `dst`, and `src` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Compute |

To copy an acceleration structure call:

    void vkCmdCopyAccelerationStructureKHR(
        VkCommandBuffer                             commandBuffer,
        const VkCopyAccelerationStructureInfoKHR*   pInfo);

- `commandBuffer` is the command buffer into which the command will be recorded.

- `pInfo` is a pointer to a VkCopyAccelerationStructureInfoKHR structure defining the copy operation.

Valid Usage

- All `VkAccelerationStructureKHR` objects referenced by this command must be bound to device memory.

- The VkDeferredOperationInfoKHR structure must not be included in the `pNext` chain of the VkCopyAccelerationStructureInfoKHR structure.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pInfo` must be a valid pointer to a valid VkCopyAccelerationStructureInfoKHR structure

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support compute operations

- This command must only be called outside of a render pass instance

Host Synchronization

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Compute |

The `VkCopyAccelerationStructureInfoKHR` structure is defined as:

    typedef struct VkCopyAccelerationStructureInfoKHR {
        VkStructureType                       sType;
        const void*                           pNext;
        VkAccelerationStructureKHR            src;
        VkAccelerationStructureKHR            dst;
        VkCopyAccelerationStructureModeKHR    mode;
    } VkCopyAccelerationStructureInfoKHR;

- `src` is the source acceleration structure for the copy.

- `dst` is the target acceleration structure for the copy.

- `mode` is a VkCopyAccelerationStructureModeKHR value that specifies additional operations to perform during the copy.

Valid Usage

- `mode` must be `VK_COPY_ACCELERATION_STRUCTURE_MODE_COMPACT_KHR` or `VK_COPY_ACCELERATION_STRUCTURE_MODE_CLONE_KHR`

- `src` must have been built with `VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_COMPACTION_BIT_KHR` if `mode` is `VK_COPY_ACCELERATION_STRUCTURE_MODE_COMPACT_KHR`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_COPY_ACCELERATION_STRUCTURE_INFO_KHR`

- `pNext` must be `NULL` or a pointer to a valid instance of VkDeferredOperationInfoKHR

- The `sType` value of each struct in the `pNext` chain must be unique

- `src` must be a valid VkAccelerationStructureKHR handle

- `dst` must be a valid VkAccelerationStructureKHR handle

- `mode` must be a valid VkCopyAccelerationStructureModeKHR value

- Both of `dst`, and `src` must have been created, allocated, or retrieved from the same VkDevice

Possible values of `mode` specifying additional operations to perform during the copy, are:

    typedef enum VkCopyAccelerationStructureModeKHR {
        VK_COPY_ACCELERATION_STRUCTURE_MODE_CLONE_KHR = 0,
        VK_COPY_ACCELERATION_STRUCTURE_MODE_COMPACT_KHR = 1,
        VK_COPY_ACCELERATION_STRUCTURE_MODE_SERIALIZE_KHR = 2,
        VK_COPY_ACCELERATION_STRUCTURE_MODE_DESERIALIZE_KHR = 3,
        VK_COPY_ACCELERATION_STRUCTURE_MODE_CLONE_NV = VK_COPY_ACCELERATION_STRUCTURE_MODE_CLONE_KHR,
        VK_COPY_ACCELERATION_STRUCTURE_MODE_COMPACT_NV = VK_COPY_ACCELERATION_STRUCTURE_MODE_COMPACT_KHR,
        VK_COPY_ACCELERATION_STRUCTURE_MODE_MAX_ENUM_KHR = 0x7FFFFFFF
    } VkCopyAccelerationStructureModeKHR;

or the equivalent

    typedef VkCopyAccelerationStructureModeKHR VkCopyAccelerationStructureModeNV;

- `VK_COPY_ACCELERATION_STRUCTURE_MODE_CLONE_KHR` creates a direct copy of the acceleration structure specified in `src` into the one specified by `dst`. The `dst` acceleration structure must have been created with the same parameters as `src`.

- `VK_COPY_ACCELERATION_STRUCTURE_MODE_COMPACT_KHR` creates a more compact version of an acceleration structure `src` into `dst`. The acceleration structure `dst` must have been created with a `compactedSize` corresponding to the one returned by vkCmdWriteAccelerationStructuresPropertiesKHR after the build of the acceleration structure specified by `src`.

- `VK_COPY_ACCELERATION_STRUCTURE_MODE_SERIALIZE_KHR` serializes the acceleration structure to a semi-opaque format which can be reloaded on a compatible implementation.

- `VK_COPY_ACCELERATION_STRUCTURE_MODE_DESERIALIZE_KHR` deserializes the semi-opaque serialization format in the buffer to the acceleration structure.

To copy an acceleration structure to device memory call:

    void vkCmdCopyAccelerationStructureToMemoryKHR(
        VkCommandBuffer                             commandBuffer,
        const VkCopyAccelerationStructureToMemoryInfoKHR* pInfo);

This command produces the same results as vkCopyAccelerationStructureToMemoryKHR, but writes its result to a device address, and is executed on the device rather than the host. The output may not necessarily be bit-for-bit identical, but it can be equally used by either vkCmdCopyMemoryToAccelerationStructureKHR or vkCopyMemoryToAccelerationStructureKHR.

- `commandBuffer` is the command buffer into which the command will be recorded.

- `pInfo` is an a pointer to a VkCopyAccelerationStructureToMemoryInfoKHR structure defining the copy operation.

The defined header structure for the serialized data consists of:

- `VK_UUID_SIZE` bytes of data matching `VkPhysicalDeviceIDProperties`::`driverUUID`

- `VK_UUID_SIZE` bytes of data identifying the compatibility for comparison using vkGetDeviceAccelerationStructureCompatibilityKHR

- A 64-bit integer of the total size matching the value queried using `VK_QUERY_TYPE_ACCELERATION_STRUCTURE_SERIALIZATION_SIZE_KHR`

- A 64-bit integer of the deserialized size to be passed in to `VkAccelerationStructureCreateInfoKHR`::`compactedSize`

- A 64-bit integer of the count of the number of acceleration structure handles following. This will be zero for a bottom-level acceleration structure.

The corresponding handles matching the values returned by vkGetAccelerationStructureDeviceAddressKHR or vkGetAccelerationStructureHandleNV are tightly packed in the buffer following the count. The application is expected to store a mapping between those handles and the original application-generated bottom-level acceleration structures to provide when deserializing.

Valid Usage

- All `VkDeviceOrHostAddressConstKHR` referenced by this command must contain valid device addresses.

- All `VkAccelerationStructureKHR` objects referenced by this command must be bound to device memory.

- The VkDeferredOperationInfoKHR structure must not be included in the `pNext` chain of the VkCopyAccelerationStructureToMemoryInfoKHR structure.

- `mode` must be `VK_COPY_ACCELERATION_STRUCTURE_MODE_SERIALIZE_KHR`

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pInfo` must be a valid pointer to a valid VkCopyAccelerationStructureToMemoryInfoKHR structure

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support compute operations

- This command must only be called outside of a render pass instance

Host Synchronization

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Compute |

    typedef struct VkCopyAccelerationStructureToMemoryInfoKHR {
        VkStructureType                       sType;
        const void*                           pNext;
        VkAccelerationStructureKHR            src;
        VkDeviceOrHostAddressKHR              dst;
        VkCopyAccelerationStructureModeKHR    mode;
    } VkCopyAccelerationStructureToMemoryInfoKHR;

- `src` is the source acceleration structure for the copy

- `dst` is the device or host address to memory which is the target for the copy

- `mode` is a VkCopyAccelerationStructureModeKHR value that specifies additional operations to perform during the copy.

Valid Usage

- The memory pointed to by `dst` must be at least as large as the serialization size of `src`, as reported by `VK_QUERY_TYPE_ACCELERATION_STRUCTURE_SERIALIZATION_SIZE_KHR`.

- `mode` must be `VK_COPY_ACCELERATION_STRUCTURE_MODE_SERIALIZE_KHR`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_COPY_ACCELERATION_STRUCTURE_TO_MEMORY_INFO_KHR`

- `pNext` must be `NULL` or a pointer to a valid instance of VkDeferredOperationInfoKHR

- The `sType` value of each struct in the `pNext` chain must be unique

- `src` must be a valid VkAccelerationStructureKHR handle

- `dst` must be a valid VkDeviceOrHostAddressKHR union

- `mode` must be a valid VkCopyAccelerationStructureModeKHR value

To copy device memory to an acceleration structure call:

    void vkCmdCopyMemoryToAccelerationStructureKHR(
        VkCommandBuffer                             commandBuffer,
        const VkCopyMemoryToAccelerationStructureInfoKHR* pInfo);

This command can accept acceleration structures produced by either vkCmdCopyAccelerationStructureToMemoryKHR or vkCopyAccelerationStructureToMemoryKHR.

- `commandBuffer` is the command buffer into which the command will be recorded.

- `pInfo` is a pointer to a VkCopyMemoryToAccelerationStructureInfoKHR structure defining the copy operation.

The structure provided as input to deserialize is as described in vkCmdCopyAccelerationStructureToMemoryKHR, with any acceleration structure handles filled in with the newly-queried handles to bottom level acceleration structures created before deserialization. These do not need to be built at deserialize time, but must be created.

Valid Usage

- All `VkDeviceOrHostAddressKHR` referenced by this command must contain valid device addresses.

- All `VkAccelerationStructureKHR` objects referenced by this command must be bound to device memory.

- The VkDeferredOperationInfoKHR structure must not be included in the `pNext` chain of the VkCopyMemoryToAccelerationStructureInfoKHR structure.

- `mode` must be `VK_COPY_ACCELERATION_STRUCTURE_MODE_DESERIALIZE_KHR`

- The data in `pInfo->pname`:src must have a format compatible with the destination physical device as returned by vkGetDeviceAccelerationStructureCompatibilityKHR

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pInfo` must be a valid pointer to a valid VkCopyMemoryToAccelerationStructureInfoKHR structure

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support compute operations

- This command must only be called outside of a render pass instance

Host Synchronization

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Outside | Compute |

The `VkCopyMemoryToAccelerationStructureInfoKHR` structure is defined as:

    typedef struct VkCopyMemoryToAccelerationStructureInfoKHR {
        VkStructureType                       sType;
        const void*                           pNext;
        VkDeviceOrHostAddressConstKHR         src;
        VkAccelerationStructureKHR            dst;
        VkCopyAccelerationStructureModeKHR    mode;
    } VkCopyMemoryToAccelerationStructureInfoKHR;

- `src` is the device or host address to memory containing the source data for the copy.

- `dst` is the target acceleration structure for the copy.

- `mode` is a VkCopyAccelerationStructureModeKHR value that specifies additional operations to perform during the copy.

Valid Usage

- `mode` must be `VK_COPY_ACCELERATION_STRUCTURE_MODE_DESERIALIZE_KHR`

- The data in `pInfo->pname`:src must have a format compatible with the destination physical device as returned by vkGetDeviceAccelerationStructureCompatibilityKHR

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_COPY_MEMORY_TO_ACCELERATION_STRUCTURE_INFO_KHR`

- `pNext` must be `NULL` or a pointer to a valid instance of VkDeferredOperationInfoKHR

- The `sType` value of each struct in the `pNext` chain must be unique

- `src` must be a valid VkDeviceOrHostAddressConstKHR union

- `dst` must be a valid VkAccelerationStructureKHR handle

- `mode` must be a valid VkCopyAccelerationStructureModeKHR value

To check if a serialized acceleration structure is compatible with the current device call:

    VkResult vkGetDeviceAccelerationStructureCompatibilityKHR(
        VkDevice                                    device,
        const VkAccelerationStructureVersionKHR*    version);

- `device` is the device to check the version against.

- `version` points to the VkAccelerationStructureVersionKHR version information to check against the device.

This possible return values for `vkGetDeviceAccelerationStructureCompatibilityKHR` are:

- `VK_SUCCESS` is returned if an acceleration structure serialized with `version` as the version information is compatible with `device`.

- `VK_ERROR_INCOMPATIBLE_VERSION_KHR` is returned if an acceleration structure serialized with `version` as the version information is not compatible with `device`.

Valid Usage

- The `rayTracing` or `rayQuery` feature must be enabled

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `version` must be a valid pointer to a valid VkAccelerationStructureVersionKHR structure

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_INCOMPATIBLE_VERSION_KHR`

The `VkAccelerationStructureVersionKHR` structure is defined as:

    typedef struct VkAccelerationStructureVersionKHR {
        VkStructureType    sType;
        const void*        pNext;
        const uint8_t*     versionData;
    } VkAccelerationStructureVersionKHR;

- `versionData` is a pointer to the version header as defined in VkCopyAccelerationStructureModeKHR

Valid Usage

- TBD

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_VERSION_KHR`

- `pNext` must be `NULL`

- `versionData` must be a valid pointer to an array of `2`*VK_UUID_SIZE `uint8_t` values

### 35.5. Host Acceleration Structure Operations

Implementations are also required to provide host implementations of the acceleration structure operations if the `rayTracingHostAccelerationStructureCommands` feature is enabled:

- vkBuildAccelerationStructureKHR corresponding to vkCmdBuildAccelerationStructureKHR

- vkCopyAccelerationStructureKHR corresponding to vkCmdCopyAccelerationStructureKHR

- vkCopyAccelerationStructureToMemoryKHR corresponding to vkCmdCopyAccelerationStructureToMemoryKHR

- vkCopyMemoryToAccelerationStructureKHR corresponding to vkCmdCopyMemoryToAccelerationStructureKHR

- vkWriteAccelerationStructuresPropertiesKHR corresponding to vkCmdWriteAccelerationStructuresPropertiesKHR

These commands are functionally equivalent to their device counterparts, except that they are executed on the host timeline, rather than being enqueued into command buffers.

All acceleration structures used by the host commands must be bound to host-visible memory, and all input data for acceleration structure builds must be referenced using host addresses instead of device addresses. Applications are not required to map acceleration structure memory when using the host commands.

| Note The vkBuildAccelerationStructureKHR and vkCmdBuildAccelerationStructureKHR may use different algorithms, and thus are not required to produce identical structures. The structures produced by these two commands may exhibit different memory footprints or traversal performance, but should strive to be similar where possible. Apart from these details, the host and device operations are interchangable. For example, an application can use vkBuildAccelerationStructureKHR to build a structure, compact it on the device using vkCmdCopyAccelerationStructureKHR, and serialize the result using vkCopyAccelerationStructureToMemoryKHR.

To build acceleration structures on the host, call:

    VkResult vkBuildAccelerationStructureKHR(
        VkDevice                                    device,
        uint32_t                                    infoCount,
        const VkAccelerationStructureBuildGeometryInfoKHR* pInfos,
        const VkAccelerationStructureBuildOffsetInfoKHR* const* ppOffsetInfos);

This command fulfills the same task as vkCmdBuildAccelerationStructureKHR but executed by the host.

- `device` is the `VkDevice` for which the acceleration structures are being built.

- `infoCount` is the number of acceleration structures to build. It specifies the number of the `pInfos` structures and `ppOffsetInfos` pointers that must be provided.

- `pInfos` is a pointer to an array of `infoCount` VkAccelerationStructureBuildGeometryInfoKHR structures defining the geometry used to build each acceleration structure.

- `ppOffsetInfos` is an array of `infoCount` pointers to arrays of VkAccelerationStructureBuildOffsetInfoKHR structures. Each `ppOffsetInfos`[i] is an array of `pInfos`[i]→`geometryCount` VkAccelerationStructureBuildOffsetInfoKHR structures defining dynamic offsets to the addresses where geometry data is stored, as defined by `pInfos`[i].

The `vkBuildAccelerationStructureKHR` command provides the ability to initiate multiple acceleration structures builds, however there is no ordering or synchronization implied between any of the individual acceleration structure builds.

| Note This means that an application cannot build a top-level acceleration structure in the same vkBuildAccelerationStructureKHR call as the associated bottom-level or instance acceleration structures are being built. There also cannot be any memory aliasing between any acceleration structure memories or scratch memories being used by any of the builds.

If the VkDeferredOperationInfoKHR structure is included in the `pNext` chain of any VkAccelerationStructureBuildGeometryInfoKHR structure, the operation of this command is deferred, as defined in the Deferred Host Operations chapter.

Valid Usage

- `pOffsetInfos`[i] must be a valid pointer to an array of `pInfos`[i]→`geometryCount` `VkAccelerationStructureBuildOffsetInfoKHR` structures

- Each `pInfos`[i].`srcAccelerationStructure` must not refer to the same acceleration structure as any `pInfos`[i].`dstAccelerationStructure` that is provided to the same build command unless it is identical for an update

- For each `pInfos`[i], `dstAccelerationStructure` must have been created with compatible VkAccelerationStructureCreateInfoKHR where VkAccelerationStructureCreateInfoKHR::`type` and VkAccelerationStructureCreateInfoKHR::`flags` are identical to VkAccelerationStructureBuildGeometryInfoKHR::`type` and VkAccelerationStructureBuildGeometryInfoKHR::`flags` respectively, VkAccelerationStructureBuildGeometryInfoKHR::`geometryCount` for `dstAccelerationStructure` are greater than or equal to the build size, and each geometry in VkAccelerationStructureBuildGeometryInfoKHR::`ppGeometries` for `dstAccelerationStructure` has greater than or equal to the number of vertices, indices, and AABBs, VkAccelerationStructureGeometryTrianglesDataKHR::`transformData` is both 0 or both non-zero, and all other parameters are the same.

- For each `pInfos`[i], if `update` is `VK_TRUE`, then objects that were previously active for that acceleration structure must not be made inactive as per Inactive Primitives and Instances

- For each `pInfos`[i], if `update` is `VK_TRUE`, then objects that were previously inactive for that acceleration structure must not be made active as per Inactive Primitives and Instances

- Any acceleration structure instance in any top level build in this command must not reference any bottom level acceleration structure built by this command

- There must not be any memory aliasing between the scratch memories that are provided in all the `pInfos`[i].`scratchData` memories for the acceleration structure builds

- There must not be any memory aliasing between memory bound to any top level, bottom level, or instance acceleration structure accessed by this command

- All VkDeviceOrHostAddressKHR or VkDeviceOrHostAddressConstKHR referenced by this command must contain valid host addresses

- All `VkAccelerationStructureKHR` objects referenced by this command must be bound to host-visible memory

- The `VkPhysicalDeviceRayTracingFeaturesKHR`→`rayTracingHostAccelerationStructureCommands` feature must be enabled

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pInfos` must be a valid pointer to an array of `infoCount` valid VkAccelerationStructureBuildGeometryInfoKHR structures

- `ppOffsetInfos` must be a valid pointer to an array of `infoCount` VkAccelerationStructureBuildOffsetInfoKHR structures

- `infoCount` must be greater than `0`

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_OPERATION_DEFERRED_KHR`

  - `VK_OPERATION_NOT_DEFERRED_KHR`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

To copy or compact an acceleration structure on the host, call:

    VkResult vkCopyAccelerationStructureKHR(
        VkDevice                                    device,
        const VkCopyAccelerationStructureInfoKHR*   pInfo);

This command fulfills the same task as vkCmdCopyAccelerationStructureKHR but executed by the host.

- `device` is the device which owns the acceleration structures.

- `pInfo` is a pointer to a VkCopyAccelerationStructureInfoKHR structure defining the copy operation.

If the VkDeferredOperationInfoKHR structure is included in the `pNext` chain of the VkCopyAccelerationStructureInfoKHR structure, the operation of this command is deferred, as defined in the Deferred Host Operations chapter.

Valid Usage

- All `VkAccelerationStructureKHR` objects referenced by this command must be bound to host-visible memory.

- the `VkPhysicalDeviceRayTracingFeaturesKHR`→`rayTracingHostAccelerationStructureCommands` feature must be enabled

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pInfo` must be a valid pointer to a valid VkCopyAccelerationStructureInfoKHR structure

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_OPERATION_DEFERRED_KHR`

  - `VK_OPERATION_NOT_DEFERRED_KHR`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

    VkResult vkCopyMemoryToAccelerationStructureKHR(
        VkDevice                                    device,
        const VkCopyMemoryToAccelerationStructureInfoKHR* pInfo);

This command fulfills the same task as vkCmdCopyMemoryToAccelerationStructureKHR but is executed by the host.

This command can accept acceleration structures produced by either vkCmdCopyAccelerationStructureToMemoryKHR or vkCopyAccelerationStructureToMemoryKHR.

- `device` is the device which owns `pInfo->pname`:dst.

- `pInfo` is a pointer to a VkCopyMemoryToAccelerationStructureInfoKHR structure defining the copy operation.

If the VkDeferredOperationInfoKHR structure is included in the `pNext` chain of the VkCopyMemoryToAccelerationStructureInfoKHR structure, the operation of this command is deferred, as defined in the Deferred Host Operations chapter.

Valid Usage

- All `VkAccelerationStructureKHR` objects referenced by this command must be bound to host-visible memory.

- All `VkDeviceOrHostAddressConstKHR` referenced by this command must contain valid host pointers.

- the `VkPhysicalDeviceRayTracingFeaturesKHR`→`rayTracingHostAccelerationStructureCommands` feature must be enabled

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pInfo` must be a valid pointer to a valid VkCopyMemoryToAccelerationStructureInfoKHR structure

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_OPERATION_DEFERRED_KHR`

  - `VK_OPERATION_NOT_DEFERRED_KHR`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

    VkResult vkCopyAccelerationStructureToMemoryKHR(
        VkDevice                                    device,
        const VkCopyAccelerationStructureToMemoryInfoKHR* pInfo);

This command fulfills the same task as vkCmdCopyAccelerationStructureToMemoryKHR but executed by the host.

This command produces the same results as vkCmdCopyAccelerationStructureToMemoryKHR, but writes its result directly to a host pointer, and is executed on the host rather than the device. The output may not necessarily be bit-for-bit identical, but it can be equally used by either vkCmdCopyMemoryToAccelerationStructureKHR or vkCopyMemoryToAccelerationStructureKHR.

- `device` is the device which owns `pInfo->pname`:src.

- `pInfo` is a pointer to a VkCopyAccelerationStructureToMemoryInfoKHR structure defining the copy operation.

If the VkDeferredOperationInfoKHR structure is included in the `pNext` chain of the VkCopyAccelerationStructureToMemoryInfoKHR structure, the operation of this command is deferred, as defined in the Deferred Host Operations chapter.

Valid Usage

- All `VkAccelerationStructureKHR` objects referenced by this command must be bound to host-visible memory.

- All `VkDeviceOrHostAddressKHR` referenced by this command must contain valid host pointers.

- the `VkPhysicalDeviceRayTracingFeaturesKHR`→`rayTracingHostAccelerationStructureCommands` feature must be enabled

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pInfo` must be a valid pointer to a valid VkCopyAccelerationStructureToMemoryInfoKHR structure

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_OPERATION_DEFERRED_KHR`

  - `VK_OPERATION_NOT_DEFERRED_KHR`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

    VkResult vkWriteAccelerationStructuresPropertiesKHR(
        VkDevice                                    device,
        uint32_t                                    accelerationStructureCount,
        const VkAccelerationStructureKHR*           pAccelerationStructures,
        VkQueryType                                 queryType,
        size_t                                      dataSize,
        void*                                       pData,
        size_t                                      stride);

This command fulfills the same task as vkCmdWriteAccelerationStructuresPropertiesKHR but executed by the host.

- `device` is the device which owns the acceleration structures in `pAccelerationStructures`.

- `accelerationStructureCount` is the count of acceleration structures for which to query the property.

- `pAccelerationStructures` points to an array of existing previously built acceleration structures.

- `queryType` is a VkQueryType value specifying the property to be queried.

- `dataSize` is the size in bytes of the buffer pointed to by `pData`.

- `pData` is a pointer to a user-allocated buffer where the results will be written.

- `stride` is the stride in bytes between results for individual queries within `pData`.

Valid Usage

- If `queryType` is `VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_KHR`, then `stride` must be a multiple of the size of `VkDeviceSize`

- If `queryType` is `VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_KHR`, then `data` must point to a `VkDeviceSize`

- If `queryType` is `VK_QUERY_TYPE_ACCELERATION_STRUCTURE_SERIALIZATION_SIZE_KHR`, then `stride` must be a multiple of the size of `VkDeviceSize`

- If `queryType` is `VK_QUERY_TYPE_ACCELERATION_STRUCTURE_SERIALIZATION_SIZE_KHR`, then `data` must point to a `VkDeviceSize`

- `dataSize` must be greater than or equal to `accelerationStructureCount`*`stride`

- The acceleration structures referenced by `pAccelerationStructures` must be bound to host-visible memory

- All acceleration structures in `accelerationStructures` must have been built with `VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_COMPACTION_BIT_KHR` if `queryType` is `VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_KHR`

- `queryType` must be `VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_KHR` or `VK_QUERY_TYPE_ACCELERATION_STRUCTURE_SERIALIZATION_SIZE_KHR`

- the `VkPhysicalDeviceRayTracingFeaturesKHR`→`rayTracingHostAccelerationStructureCommands` feature must be enabled

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pAccelerationStructures` must be a valid pointer to an array of `accelerationStructureCount` valid VkAccelerationStructureKHR handles

- `queryType` must be a valid VkQueryType value

- `pData` must be a valid pointer to an array of `dataSize` bytes

- `accelerationStructureCount` must be greater than `0`

- `dataSize` must be greater than `0`

- Each element of `pAccelerationStructures` must have been created, allocated, or retrieved from `device`

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

## 36. Extending Vulkan

New functionality may be added to Vulkan via either new extensions or new versions of the core, or new versions of an extension in some cases.

This chapter describes how Vulkan is versioned, how compatibility is affected between different versions, and compatibility rules that are followed by the Vulkan Working Group.

### 36.1. Instance and Device Functionality

Commands that enumerate instance properties, or that accept a VkInstance object as a parameter, are considered instance-level functionality. Commands that enumerate physical device properties, or that accept a VkDevice object or any of a device’s child objects as a parameter, are considered device-level functionality.

| Note Applications usually interface to Vulkan using a loader that implements only instance-level functionality, passing device-level functionality to implementations of the full Vulkan API on the system. In some circumstances, as these may be implemented independently, it is possible that the loader and device implementations on a given installation will support different versions. To allow for this and call out when it happens, the Vulkan specification enumerates device and instance level functionality separately - they have independent version queries.

| Note Vulkan 1.0 initially specified new physical device enumeration functionality as instance-level, requiring it to be included in an instance extension. As the capabilities of device-level functionality require discovery via physical device enumeration, this led to the situation where many device extensions required an instance extension as well. To alleviate this extra work, `VK_KHR_get_physical_device_properties2` (and subsequently Vulkan 1.1) redefined device-level functionality to include physical device enumeration.

### 36.2. Core Versions

The Vulkan Specification is regularly updated with bug fixes and clarifications. Occasionally new functionality is added to the core and at some point it is expected that there will be a desire to perform a large, breaking change to the API. In order to indicate to developers how and when these changes are made to the specification, and to provide a way to identify each set of changes, the Vulkan API maintains a version number.

#### 36.2.1. Version Numbers

The Vulkan version number comprises three parts indicating the major, minor and patch version of the Vulkan API Specification.

The major version indicates a significant change in the API, which will encompass a wholly new version of the specification.

The minor version indicates the incorporation of new functionality into the core specification.

The patch version indicates bug fixes, clarifications, and language improvements have been incorporated into the specification.

Compatibility guarantees made about versions of the API sharing any of the same version numbers are documented in Core Versions

The version number is used in several places in the API. In each such use, the version numbers are packed into a 32-bit integer as follows:

- The major version is a 10-bit integer packed into bits 31-22.

- The minor version number is a 10-bit integer packed into bits 21-12.

- The patch version number is a 12-bit integer packed into bits 11-0.

`VK_VERSION_MAJOR` extracts the API major version number from a packed version number:

    #define VK_VERSION_MAJOR(version) ((uint32_t)(version) >> 22)

`VK_VERSION_MINOR` extracts the API minor version number from a packed version number:

    #define VK_VERSION_MINOR(version) (((uint32_t)(version) >> 12) & 0x3ff)

`VK_VERSION_PATCH` extracts the API patch version number from a packed version number:

    #define VK_VERSION_PATCH(version) ((uint32_t)(version) & 0xfff)

`VK_MAKE_VERSION` constructs an API version number.

    #define VK_MAKE_VERSION(major, minor, patch) \
        (((major) << 22) | ((minor) << 12) | (patch))

- `major` is the major version number.

- `minor` is the minor version number.

- `patch` is the patch version number.

`VK_API_VERSION_1_0` returns the API version number for Vulkan 1.0.0.

    // Vulkan 1.0 version number
    #define VK_API_VERSION_1_0 VK_MAKE_VERSION(1, 0, 0)// Patch version should always be set to 0

`VK_API_VERSION_1_1` returns the API version number for Vulkan 1.1.0.

    // Vulkan 1.1 version number
    #define VK_API_VERSION_1_1 VK_MAKE_VERSION(1, 1, 0)// Patch version should always be set to 0

`VK_API_VERSION_1_2` returns the API version number for Vulkan 1.2.0.

    // Vulkan 1.2 version number
    #define VK_API_VERSION_1_2 VK_MAKE_VERSION(1, 2, 0)// Patch version should always be set to 0

#### 36.2.2. Querying Version Support

The version of instance-level functionality can be queried by calling vkEnumerateInstanceVersion.

The version of device-level functionality can be queried by calling vkGetPhysicalDeviceProperties or vkGetPhysicalDeviceProperties2, and is returned in VkPhysicalDeviceProperties::`apiVersion`, encoded as described in Version Numbers.

### 36.3. Layers

When a layer is enabled, it inserts itself into the call chain for Vulkan commands the layer is interested in. Layers can be used for a variety of tasks that extend the base behavior of Vulkan beyond what is required by the specification - such as call logging, tracing, validation, or providing additional extensions.

| Note For example, an implementation is not expected to check that the value of enums used by the application fall within allowed ranges. Instead, a validation layer would do those checks and flag issues. This avoids a performance penalty during production use of the application because those layers would not be enabled in production.

| Note Vulkan layers may wrap object handles (i.e. return a different handle value to the application than that generated by the implementation). This is generally discouraged, as it increases the probability of incompatibilities with new extensions. The validation layers wrap handles in order to track the proper use and destruction of each object. See the “Vulkan Loader Specification and Architecture Overview” document for additional information.

To query the available layers, call:

    VkResult vkEnumerateInstanceLayerProperties(
        uint32_t*                                   pPropertyCount,
        VkLayerProperties*                          pProperties);

- `pPropertyCount` is a pointer to an integer related to the number of layer properties available or queried, as described below.

- `pProperties` is either `NULL` or a pointer to an array of VkLayerProperties structures.

If `pProperties` is `NULL`, then the number of layer properties available is returned in `pPropertyCount`. Otherwise, `pPropertyCount` must point to a variable set by the user to the number of elements in the `pProperties` array, and on return the variable is overwritten with the number of structures actually written to `pProperties`. If `pPropertyCount` is less than the number of layer properties available, at most `pPropertyCount` structures will be written. If `pPropertyCount` is smaller than the number of layers available, `VK_INCOMPLETE` will be returned instead of `VK_SUCCESS`, to indicate that not all the available layer properties were returned.

The list of available layers may change at any time due to actions outside of the Vulkan implementation, so two calls to `vkEnumerateInstanceLayerProperties` with the same parameters may return different results, or retrieve different `pPropertyCount` values or `pProperties` contents. Once an instance has been created, the layers enabled for that instance will continue to be enabled and valid for the lifetime of that instance, even if some of them become unavailable for future instances.

Valid Usage (Implicit)

- `pPropertyCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pPropertyCount` is not `0`, and `pProperties` is not `NULL`, `pProperties` must be a valid pointer to an array of `pPropertyCount` VkLayerProperties structures

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkLayerProperties` structure is defined as:

    typedef struct VkLayerProperties {
        char        layerName[VK_MAX_EXTENSION_NAME_SIZE];
        uint32_t    specVersion;
        uint32_t    implementationVersion;
        char        description[VK_MAX_DESCRIPTION_SIZE];
    } VkLayerProperties;

- `layerName` is an array of `VK_MAX_EXTENSION_NAME_SIZE` `char` containing a null-terminated UTF-8 string which is the name of the layer. Use this name in the `ppEnabledLayerNames` array passed in the VkInstanceCreateInfo structure to enable this layer for an instance.

- `specVersion` is the Vulkan version the layer was written to, encoded as described in Version Numbers.

- `implementationVersion` is the version of this layer. It is an integer, increasing with backward compatible changes.

- `description` is an array of `VK_MAX_DESCRIPTION_SIZE` `char` containing a null-terminated UTF-8 string which provides additional details that can be used by the application to identify the layer.

To enable a layer, the name of the layer should be added to the `ppEnabledLayerNames` member of VkInstanceCreateInfo when creating a `VkInstance`.

Loader implementations may provide mechanisms outside the Vulkan API for enabling specific layers. Layers enabled through such a mechanism are implicitly enabled, while layers enabled by including the layer name in the `ppEnabledLayerNames` member of VkInstanceCreateInfo are explicitly enabled. Implicitly enabled layers are loaded before explicitly enabled layers, such that implicitly enabled layers are closer to the application, and explicitly enabled layers are closer to the driver. Except where otherwise specified, implicitly enabled and explicitly enabled layers differ only in the way they are enabled, and the order in which they are loaded. Explicitly enabling a layer that is implicitly enabled results in this layer being loaded as an implicitly enabled layer; it has no additional effect.

#### 36.3.1. Device Layer Deprecation

Previous versions of this specification distinguished between instance and device layers. Instance layers were only able to intercept commands that operate on `VkInstance` and `VkPhysicalDevice`, except they were not able to intercept vkCreateDevice. Device layers were enabled for individual devices when they were created, and could only intercept commands operating on that device or its child objects.

Device-only layers are now deprecated, and this specification no longer distinguishes between instance and device layers. Layers are enabled during instance creation, and are able to intercept all commands operating on that instance or any of its child objects. At the time of deprecation there were no known device-only layers and no compelling reason to create one.

In order to maintain compatibility with implementations released prior to device-layer deprecation, applications should still enumerate and enable device layers. The behavior of `vkEnumerateDeviceLayerProperties` and valid usage of the `ppEnabledLayerNames` member of `VkDeviceCreateInfo` maximizes compatibility with applications written to work with the previous requirements.

To enumerate device layers, call:

    VkResult vkEnumerateDeviceLayerProperties(
        VkPhysicalDevice                            physicalDevice,
        uint32_t*                                   pPropertyCount,
        VkLayerProperties*                          pProperties);

- `pPropertyCount` is a pointer to an integer related to the number of layer properties available or queried.

- `pProperties` is either `NULL` or a pointer to an array of VkLayerProperties structures.

If `pProperties` is `NULL`, then the number of layer properties available is returned in `pPropertyCount`. Otherwise, `pPropertyCount` must point to a variable set by the user to the number of elements in the `pProperties` array, and on return the variable is overwritten with the number of structures actually written to `pProperties`. If `pPropertyCount` is less than the number of layer properties available, at most `pPropertyCount` structures will be written. If `pPropertyCount` is smaller than the number of layers available, `VK_INCOMPLETE` will be returned instead of `VK_SUCCESS`, to indicate that not all the available layer properties were returned.

The list of layers enumerated by `vkEnumerateDeviceLayerProperties` must be exactly the sequence of layers enabled for the instance. The members of `VkLayerProperties` for each enumerated layer must be the same as the properties when the layer was enumerated by `vkEnumerateInstanceLayerProperties`.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pPropertyCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pPropertyCount` is not `0`, and `pProperties` is not `NULL`, `pProperties` must be a valid pointer to an array of `pPropertyCount` VkLayerProperties structures

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `ppEnabledLayerNames` and `enabledLayerCount` members of `VkDeviceCreateInfo` are deprecated and their values must be ignored by implementations. However, for compatibility, only an empty list of layers or a list that exactly matches the sequence enabled at instance creation time are valid, and validation layers should issue diagnostics for other cases.

Regardless of the enabled layer list provided in `VkDeviceCreateInfo`, the sequence of layers active for a device will be exactly the sequence of layers enabled when the parent instance was created.

### 36.4. Extensions

Extensions may define new Vulkan commands, structures, and enumerants. For compilation purposes, the interfaces defined by registered extensions, including new structures and enumerants as well as function pointer types for new commands, are defined in the Khronos-supplied `vulkan_core.h` together with the core API. However, commands defined by extensions may not be available for static linking - in which case function pointers to these commands should be queried at runtime as described in Command Function Pointers. Extensions may be provided by layers as well as by a Vulkan implementation.

Because extensions may extend or change the behavior of the Vulkan API, extension authors should add support for their extensions to the Khronos validation layers. This is especially important for new commands whose parameters have been wrapped by the validation layers. See the “Vulkan Loader Specification and Architecture Overview” document for additional information.

| Note To enable an instance extension, the name of the extension can be added to the `ppEnabledExtensionNames` member of VkInstanceCreateInfo when creating a `VkInstance`. To enable a device extension, the name of the extension can be added to the `ppEnabledExtensionNames` member of VkDeviceCreateInfo when creating a `VkDevice`. Physical-Device-Level functionality does not have any enabling mechanism and can be used as long as the VkPhysicalDevice supports the device extension as determined by vkEnumerateDeviceExtensionProperties. Enabling an extension does not change the behavior of functionality exposed by the core Vulkan API or any other extension, other than making valid the use of the commands, enums and structures defined by that extension. Valid Usage sections for individual commands and structures do not currently contain which extensions have to be enabled in order to make their use valid, although they might do so in the future. It is defined only in the Valid Usage for Extensions section.

#### 36.4.1. Instance Extensions

Instance extensions add new instance-level functionality to the API, outside of the core specification.

To query the available instance extensions, call:

    VkResult vkEnumerateInstanceExtensionProperties(
        const char*                                 pLayerName,
        uint32_t*                                   pPropertyCount,
        VkExtensionProperties*                      pProperties);

- `pLayerName` is either `NULL` or a pointer to a null-terminated UTF-8 string naming the layer to retrieve extensions from.

- `pPropertyCount` is a pointer to an integer related to the number of extension properties available or queried, as described below.

- `pProperties` is either `NULL` or a pointer to an array of VkExtensionProperties structures.

When `pLayerName` parameter is `NULL`, only extensions provided by the Vulkan implementation or by implicitly enabled layers are returned. When `pLayerName` is the name of a layer, the instance extensions provided by that layer are returned.

If `pProperties` is `NULL`, then the number of extensions properties available is returned in `pPropertyCount`. Otherwise, `pPropertyCount` must point to a variable set by the user to the number of elements in the `pProperties` array, and on return the variable is overwritten with the number of structures actually written to `pProperties`. If `pPropertyCount` is less than the number of extension properties available, at most `pPropertyCount` structures will be written. If `pPropertyCount` is smaller than the number of extensions available, `VK_INCOMPLETE` will be returned instead of `VK_SUCCESS`, to indicate that not all the available properties were returned.

Because the list of available layers may change externally between calls to vkEnumerateInstanceExtensionProperties, two calls may retrieve different results if a `pLayerName` is available in one call but not in another. The extensions supported by a layer may also change between two calls, e.g. if the layer implementation is replaced by a different version between those calls.

Implementations must not advertise any pair of extensions that cannot be enabled together due to behavioral differences, or any extension that cannot be enabled against the advertised version.

Valid Usage (Implicit)

- If `pLayerName` is not `NULL`, `pLayerName` must be a null-terminated UTF-8 string

- `pPropertyCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pPropertyCount` is not `0`, and `pProperties` is not `NULL`, `pProperties` must be a valid pointer to an array of `pPropertyCount` VkExtensionProperties structures

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_LAYER_NOT_PRESENT`

#### 36.4.2. Device Extensions

Device extensions add new device-level functionality to the API, outside of the core specification.

To query the extensions available to a given physical device, call:

    VkResult vkEnumerateDeviceExtensionProperties(
        VkPhysicalDevice                            physicalDevice,
        const char*                                 pLayerName,
        uint32_t*                                   pPropertyCount,
        VkExtensionProperties*                      pProperties);

- `physicalDevice` is the physical device that will be queried.

- `pLayerName` is either `NULL` or a pointer to a null-terminated UTF-8 string naming the layer to retrieve extensions from.

- `pPropertyCount` is a pointer to an integer related to the number of extension properties available or queried, and is treated in the same fashion as the vkEnumerateInstanceExtensionProperties::`pPropertyCount` parameter.

- `pProperties` is either `NULL` or a pointer to an array of VkExtensionProperties structures.

When `pLayerName` parameter is `NULL`, only extensions provided by the Vulkan implementation or by implicitly enabled layers are returned. When `pLayerName` is the name of a layer, the device extensions provided by that layer are returned.

Implementations must not advertise any pair of extensions that cannot be enabled together due to behavioral differences, or any extension that cannot be enabled against the advertised version.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- If `pLayerName` is not `NULL`, `pLayerName` must be a null-terminated UTF-8 string

- `pPropertyCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pPropertyCount` is not `0`, and `pProperties` is not `NULL`, `pProperties` must be a valid pointer to an array of `pPropertyCount` VkExtensionProperties structures

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_LAYER_NOT_PRESENT`

The `VkExtensionProperties` structure is defined as:

    typedef struct VkExtensionProperties {
        char        extensionName[VK_MAX_EXTENSION_NAME_SIZE];
        uint32_t    specVersion;
    } VkExtensionProperties;

- `extensionName` is an array of `VK_MAX_EXTENSION_NAME_SIZE` `char` containing a null-terminated UTF-8 string which is the name of the extension.

- `specVersion` is the version of this extension. It is an integer, incremented with backward compatible changes.

### 36.5. Extension Dependencies

Some extensions are dependent on other extensions to function. To enable extensions with dependencies, such required extensions must also be enabled through the same API mechanisms when creating an instance with vkCreateInstance or a device with vkCreateDevice. Each extension which has such dependencies documents them in the appendix summarizing that extension.

If an extension is supported (as queried by vkEnumerateInstanceExtensionProperties or vkEnumerateDeviceExtensionProperties), then required extensions of that extension must also be supported for the same instance or physical device.

Any device extension that has an instance extension dependency that is not enabled by vkCreateInstance is considered to be unsupported, hence it must not be returned by vkEnumerateDeviceExtensionProperties for any VkPhysicalDevice child of the instance.

If a required extension has been promoted to another extension or to a core API version, then as a general rule, the dependency is also satisfied by the promoted extension or core version. This will be true so long as any features required by the original extension are also required or enabled by the promoted extension or core version. However, in some cases an extension is promoted while making some of its features optional in the promoted extension or core version. In this case, the dependency may not be satisfied. The only way to be certain is to look at the descriptions of the original dependency and the promoted version in the Layers & Extensions and Core Revisions appendices.

| Note There is metadata in `vk.xml` describing some aspects of promotion, especially `requires`, `promotedto` and `deprecatedby` attributes of `<extension>` tags. However, the metadata does not yet fully describe this scenario. In the future, we may extend the XML schema to describe the full set of extensions and versions satisfying a dependency.

### 36.6. Compatibility Guarantees (Informative)

This section is marked as informal as there is no binding responsibility on implementations of the Vulkan API - these guarantees are however a contract between the Vulkan Working Group and developers using this Specification.

#### 36.6.1. Core Versions

Each of the major, minor, and patch versions of the Vulkan specification provide different compatibility guarantees.

##### Patch Versions

A difference in the patch version indicates that a set of bug fixes or clarifications have been made to the Specification. Informative enums returned by Vulkan commands that will not affect the runtime behavior of a valid application may be added in a patch version (e.g. VkVendorId).

The specification’s patch version is strictly increasing for a given major version of the specification; any change to a specification as described above will result in the patch version being increased by 1. Patch versions are applied to all minor versions, even if a given minor version is not affected by the provoking change.

Specifications with different patch versions but the same major and minor version are fully compatible with each other - such that a valid application written against one will work with an implementation of another.

| Note If a patch version includes a bug fix or clarification that could have a significant impact on developer expectations, these will be highlighted in the change log. Generally the Vulkan Working Group tries to avoid these kinds of changes, instead fixing them in either an extension or core version.

##### Minor Versions

Changes in the minor version of the specification indicate that new functionality has been added to the core specification. This will usually include new interfaces in the header, and may also include behavior changes and bug fixes. Core functionality may be deprecated in a minor version, but will not be obsoleted or removed.

The specification’s minor version is strictly increasing for a given major version of the specification; any change to a specification as described above will result in the minor version being increased by 1. Changes that can be accommodated in a patch version will not increase the minor version.

Specifications with a lower minor version are backwards compatible with an implementation of a specification with a higher minor version for core functionality and extensions issued with the KHR vendor tag. Vendor and multi-vendor extensions are not guaranteed to remain functional across minor versions, though in general they are with few exceptions - see Obsoletion for more information.

##### Major Versions

A difference in the major version of specifications indicates a large set of changes which will likely include interface changes, behavioral changes, removal of deprecated functionality, and the modification, addition, or replacement of other functionality.

The specification’s major version is monotonically increasing; any change to the specification as described above will result in the major version being increased. Changes that can be accommodated in a patch or minor version will not increase the major version.

The Vulkan Working Group intends to only issue a new major version of the Specification in order to realise significant improvements to the Vulkan API that will necessarily require breaking compatibility.

A new major version will likely include a wholly new version of the specification to be issued - which could include an overhaul of the versioning semantics for the minor and patch versions. The patch and minor versions of a specification are therefore not meaningful across major versions. If a major version of the specification includes similar versioning semantics, it is expected that the the patch and minor version will be reset to 0 for that major version.

#### 36.6.2. Extensions

A KHR extension must be able to be enabled alongside any other KHR extension, and for any minor or patch version of the core Specification beyond the minimum version it requires. A multi-vendor extension should be able to be enabled alongside any KHR extension or other multi-vendor extension, and for any minor or patch version of the core Specification beyond the minimum version it requires. A vendor extension should be able to be enabled alongside any KHR extension, multi-vendor extension, or other vendor extension from the same vendor, and for any minor or patch version of the core Specification beyond the minimum version it requires. A vendor extension may be able to be enabled alongside vendor extensions from another vendor.

The one other exception to this is if a vendor or multi-vendor extension is made obsolete by either a core version or another extension, which will be highlighted in the extension appendix.

##### Promotion

Extensions, or features of an extension, may be promoted to a new core version of the API, or a newer extension which an equal or greater number of implementors are in favour of.

When extension functionality is promoted, minor changes may be introduced, limited to the following:

- Naming

- Non-intrusive parameters changes

- Feature advertisement/enablement

- Combining structure parameters into larger structures

- Author ID suffixes changed or removed

| Note If extension functionality is promoted, there is no guarantee of direct compatibility, however it should require little effort to port code from the original feature to the promoted one. The Vulkan Working Group endeavours to ensure that larger changes are marked as either deprecated or obsoleted as appropriate, and can do so retroactively if necessary.

Extensions that are promoted are listed as being promoted in their extension appendices, with reference to where they were promoted to.

When an extension is promoted, any backwards compatibility aliases which exist in the extension will not be promoted.

| Note As a hypothetical example, if the `VK_KHR_surface` extension were promoted to part of a future core version, the `VK_COLOR_SPACE_SRGB_NONLINEAR_KHR` token defined by that extension would be promoted to `VK_COLOR_SPACE_SRGB_NONLINEAR`. However, the `VK_COLORSPACE_SRGB_NONLINEAR_KHR` token aliases `VK_COLOR_SPACE_SRGB_NONLINEAR_KHR`. The `VK_COLORSPACE_SRGB_NONLINEAR_KHR` would not be promoted, because it is a backwards compatibility alias that exists only due to a naming mistake when the extension was initially published.

##### Deprecation

Extensions may be marked as deprecated when the intended use cases either become irrelevant or can be solved in other ways. Generally, a new feature will become available to solve the use case in another extension or core version of the API, but it is not guaranteed.

| Note Features that are intended to replace deprecated functionality have no guarantees of compatibility, and applications may require drastic modification in order to make use of the new features.

Extensions that are deprecated are listed as being deprecated in their extension appendices, with an explanation of the deprecation and any features that are relevant.

##### Obsoletion

Occasionally, an extension will be marked as obsolete if a new version of the core API or a new extension is fundamentally incompatible with it. An obsoleted extension must not be used with the extension or core version that obsoleted it.

Extensions that are obsoleted are listed as being obsoleted in their extension appendices, with reference to what they were obsoleted by.

##### Aliases

When an extension is promoted or deprecated by a newer feature, some or all of its functionality may be replicated into the newer feature. Rather than duplication of all the documentation and definitions, the specification instead identifies the identical commands and types as aliases of one another. Each alias is mentioned together with the definition it aliases, with the older aliases marked as “equivalents”. Each alias of the same command has identical behavior, and each alias of the same type has identical meaning - they can be used interchangeably in an application with no compatibility issues.

| Note For promoted types, the aliased extension type is semantically identical to the new core type. The C99 headers simply `typedef` the older aliases to the promoted types. For promoted command aliases, however, there are two separate entry point definitions, due to the fact that the C99 ABI has no way to alias command definitions without resorting to macros. Calling via either entry point definition will produce identical behavior within the bounds of the specification, and should still invoke the same entry point in the implementation. Debug tools may use separate entry points with different debug behavior; to write the appropriate command name to an output log, for instance.

## 37. Features

Features describe functionality which is not supported on all implementations. Features are properties of the physical device. Features are optional, and must be explicitly enabled before use. Support for features is reported and enabled on a per-feature basis.

| Note Features are reported via the basic VkPhysicalDeviceFeatures structure, as well as the extensible structure `VkPhysicalDeviceFeatures2`, which was added in the `VK_KHR_get_physical_device_properties2` extension and included in Vulkan 1.1. When new features are added in future Vulkan versions or extensions, each extension should introduce one new feature structure, if needed. This structure can be added to the `pNext` chain of the `VkPhysicalDeviceFeatures2` structure.

For convenience, new core versions of Vulkan may introduce new unified features structures for features promoted from extensions. At the same time, the extension’s original features structure (if any) is also promoted to the core API, and is an alias of the extension’s structure. This results in multiple names for the same feature: in the original extension’s feature structure and the promoted structure alias, in the unified feature structure. When a feature was implicitly supported and enabled in the extension, but an explicit name was added during promotion, then the extension itself acts as an alias for the feature as listed in the table below.

All aliases of the same feature in the core API must be reported consistently: either all must be reported as supported, or none of them. When a promoted extension is available, any corresponding feature aliases must be supported.

Table 44. Extension Feature Aliases
Extension | Feature(s)
--- | ---
`VK_KHR_draw_indirect_count` | drawIndirectCount
`VK_KHR_sampler_mirror_clamp_to_edge` | samplerMirrorClampToEdge
`VK_EXT_descriptor_indexing` | descriptorIndexing
`VK_EXT_sampler_filter_minmax` | samplerFilterMinmax
`VK_EXT_shader_viewport_index_layer` | shaderOutputViewportIndex, shaderOutputLayer

To query supported features, call:

    void vkGetPhysicalDeviceFeatures(
        VkPhysicalDevice                            physicalDevice,
        VkPhysicalDeviceFeatures*                   pFeatures);

- `physicalDevice` is the physical device from which to query the supported features.

- `pFeatures` is a pointer to a VkPhysicalDeviceFeatures structure in which the physical device features are returned. For each feature, a value of `VK_TRUE` specifies that the feature is supported on this physical device, and `VK_FALSE` specifies that the feature is not supported.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pFeatures` must be a valid pointer to a VkPhysicalDeviceFeatures structure

Fine-grained features used by a logical device must be enabled at `VkDevice` creation time. If a feature is enabled that the physical device does not support, `VkDevice` creation will fail and return `VK_ERROR_FEATURE_NOT_PRESENT`.

The fine-grained features are enabled by passing a pointer to the `VkPhysicalDeviceFeatures` structure via the `pEnabledFeatures` member of the `VkDeviceCreateInfo` structure that is passed into the `vkCreateDevice` call. If a member of `pEnabledFeatures` is set to `VK_TRUE` or `VK_FALSE`, then the device will be created with the indicated feature enabled or disabled, respectively. Features can also be enabled by using the VkPhysicalDeviceFeatures2 structure.

If an application wishes to enable all features supported by a device, it can simply pass in the `VkPhysicalDeviceFeatures` structure that was previously returned by `vkGetPhysicalDeviceFeatures`. To disable an individual feature, the application can set the desired member to `VK_FALSE` in the same structure. Setting `pEnabledFeatures` to `NULL` and not including a VkPhysicalDeviceFeatures2 in the `pNext` chain of VkDeviceCreateInfo is equivalent to setting all members of the structure to `VK_FALSE`.

| Note Some features, such as `robustBufferAccess`, may incur a run-time performance cost. Application writers should carefully consider the implications of enabling all supported features.

To query supported features defined by the core or extensions, call:

    void vkGetPhysicalDeviceFeatures2(
        VkPhysicalDevice                            physicalDevice,
        VkPhysicalDeviceFeatures2*                  pFeatures);

or the equivalent command

    void vkGetPhysicalDeviceFeatures2KHR(
        VkPhysicalDevice                            physicalDevice,
        VkPhysicalDeviceFeatures2*                  pFeatures);

- `physicalDevice` is the physical device from which to query the supported features.

- `pFeatures` is a pointer to a VkPhysicalDeviceFeatures2 structure in which the physical device features are returned.

Each structure in `pFeatures` and its `pNext` chain contains members corresponding to fine-grained features. `vkGetPhysicalDeviceFeatures2` writes each member to a boolean value indicating whether that feature is supported.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pFeatures` must be a valid pointer to a VkPhysicalDeviceFeatures2 structure

The `VkPhysicalDeviceFeatures2` structure is defined as:

    typedef struct VkPhysicalDeviceFeatures2 {
        VkStructureType             sType;
        void*                       pNext;
        VkPhysicalDeviceFeatures    features;
    } VkPhysicalDeviceFeatures2;

or the equivalent

    typedef VkPhysicalDeviceFeatures2 VkPhysicalDeviceFeatures2KHR;

The `VkPhysicalDeviceFeatures2` structure is defined as:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `features` is a VkPhysicalDeviceFeatures structure describing the fine-grained features of the Vulkan 1.0 API.

The `pNext` chain of this structure is used to extend the structure with features defined by extensions. This structure can be used in vkGetPhysicalDeviceFeatures2 or can be included in the `pNext` chain of a VkDeviceCreateInfo structure, in which case it controls which features are enabled in the device in lieu of `pEnabledFeatures`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FEATURES_2`

The `VkPhysicalDeviceFeatures` structure is defined as:

    typedef struct VkPhysicalDeviceFeatures {
        VkBool32    robustBufferAccess;
        VkBool32    fullDrawIndexUint32;
        VkBool32    imageCubeArray;
        VkBool32    independentBlend;
        VkBool32    geometryShader;
        VkBool32    tessellationShader;
        VkBool32    sampleRateShading;
        VkBool32    dualSrcBlend;
        VkBool32    logicOp;
        VkBool32    multiDrawIndirect;
        VkBool32    drawIndirectFirstInstance;
        VkBool32    depthClamp;
        VkBool32    depthBiasClamp;
        VkBool32    fillModeNonSolid;
        VkBool32    depthBounds;
        VkBool32    wideLines;
        VkBool32    largePoints;
        VkBool32    alphaToOne;
        VkBool32    multiViewport;
        VkBool32    samplerAnisotropy;
        VkBool32    textureCompressionETC2;
        VkBool32    textureCompressionASTC_LDR;
        VkBool32    textureCompressionBC;
        VkBool32    occlusionQueryPrecise;
        VkBool32    pipelineStatisticsQuery;
        VkBool32    vertexPipelineStoresAndAtomics;
        VkBool32    fragmentStoresAndAtomics;
        VkBool32    shaderTessellationAndGeometryPointSize;
        VkBool32    shaderImageGatherExtended;
        VkBool32    shaderStorageImageExtendedFormats;
        VkBool32    shaderStorageImageMultisample;
        VkBool32    shaderStorageImageReadWithoutFormat;
        VkBool32    shaderStorageImageWriteWithoutFormat;
        VkBool32    shaderUniformBufferArrayDynamicIndexing;
        VkBool32    shaderSampledImageArrayDynamicIndexing;
        VkBool32    shaderStorageBufferArrayDynamicIndexing;
        VkBool32    shaderStorageImageArrayDynamicIndexing;
        VkBool32    shaderClipDistance;
        VkBool32    shaderCullDistance;
        VkBool32    shaderFloat64;
        VkBool32    shaderInt64;
        VkBool32    shaderInt16;
        VkBool32    shaderResourceResidency;
        VkBool32    shaderResourceMinLod;
        VkBool32    sparseBinding;
        VkBool32    sparseResidencyBuffer;
        VkBool32    sparseResidencyImage2D;
        VkBool32    sparseResidencyImage3D;
        VkBool32    sparseResidency2Samples;
        VkBool32    sparseResidency4Samples;
        VkBool32    sparseResidency8Samples;
        VkBool32    sparseResidency16Samples;
        VkBool32    sparseResidencyAliased;
        VkBool32    variableMultisampleRate;
        VkBool32    inheritedQueries;
    } VkPhysicalDeviceFeatures;

The members of the `VkPhysicalDeviceFeatures` structure describe the following features:

- `robustBufferAccess` specifies that accesses to buffers are bounds-checked against the range of the buffer descriptor (as determined by `VkDescriptorBufferInfo`::`range`, `VkBufferViewCreateInfo`::`range`, or the size of the buffer). Out of bounds accesses must not cause application termination, and the effects of shader loads, stores, and atomics must conform to an implementation-dependent behavior as described below.

  - A buffer access is considered to be out of bounds if any of the following are true:

    - The pointer was formed by `OpImageTexelPointer` and the coordinate is less than zero or greater than or equal to the number of whole elements in the bound range.

    - The pointer was not formed by `OpImageTexelPointer` and the object pointed to is not wholly contained within the bound range. This includes accesses performed via variable pointers where the buffer descriptor being accessed cannot be statically determined. Uninitialized pointers and pointers equal to `OpConstantNull` are treated as pointing to a zero-sized object, so all accesses through such pointers are considered to be out of bounds. Buffer accesses through buffer device addresses are not bounds-checked. If the `cooperativeMatrixRobustBufferAccess` feature is not enabled, then accesses using `OpCooperativeMatrixLoadNV` and `OpCooperativeMatrixStoreNV` may not be bounds-checked.

      | Note If a SPIR-V `OpLoad` instruction loads a structure and the tail end of the structure is out of bounds, then all members of the structure are considered out of bounds even if the members at the end are not statically used.

    - If any buffer access is determined to be out of bounds, then any other access of the same type (load, store, or atomic) to the same buffer that accesses an address less than 16 bytes away from the out of bounds address may also be considered out of bounds.

  - Out-of-bounds buffer loads will return any of the following values:

    - Values from anywhere within the memory range(s) bound to the buffer (possibly including bytes of memory past the end of the buffer, up to the end of the bound range).

    - Zero values, or (0,0,0,x) vectors for vector reads where x is a valid value represented in the type of the vector components and may be any of:

      - 0, 1, or the maximum representable positive integer value, for signed or unsigned integer components

      - 0.0 or 1.0, for floating-point components

  - Out-of-bounds writes may modify values within the memory range(s) bound to the buffer, but must not modify any other memory.

  - Out-of-bounds atomics may modify values within the memory range(s) bound to the buffer, but must not modify any other memory, and return an undefined value.

  - Vertex input attributes are considered out of bounds if the offset of the attribute in the bound vertex buffer range plus the size of the attribute is greater than either:

    - `vertexBufferRangeSize`, if `bindingStride` == 0; or

    - (`vertexBufferRangeSize` - (`vertexBufferRangeSize` % `bindingStride`))

    where `vertexBufferRangeSize` is the byte size of the memory range bound to the vertex buffer binding and `bindingStride` is the byte stride of the corresponding vertex input binding. Further, if any vertex input attribute using a specific vertex input binding is out of bounds, then all vertex input attributes using that vertex input binding for that vertex shader invocation are considered out of bounds.

    - If a vertex input attribute is out of bounds, it will be assigned one of the following values:

      - Values from anywhere within the memory range(s) bound to the buffer, converted according to the format of the attribute.

      - Zero values, format converted according to the format of the attribute.

      - Zero values, or (0,0,0,x) vectors, as described above.

  - If `robustBufferAccess` is not enabled, applications must not perform out of bounds accesses.

- `fullDrawIndexUint32` specifies the full 32-bit range of indices is supported for indexed draw calls when using a VkIndexType of `VK_INDEX_TYPE_UINT32`. `maxDrawIndexedIndexValue` is the maximum index value that may be used (aside from the primitive restart index, which is always 232-1 when the VkIndexType is `VK_INDEX_TYPE_UINT32`). If this feature is supported, `maxDrawIndexedIndexValue` must be 232-1; otherwise it must be no smaller than 224-1. See maxDrawIndexedIndexValue.

- `imageCubeArray` specifies whether image views with a VkImageViewType of `VK_IMAGE_VIEW_TYPE_CUBE_ARRAY` can be created, and that the corresponding `SampledCubeArray` and `ImageCubeArray` SPIR-V capabilities can be used in shader code.

- `independentBlend` specifies whether the `VkPipelineColorBlendAttachmentState` settings are controlled independently per-attachment. If this feature is not enabled, the `VkPipelineColorBlendAttachmentState` settings for all color attachments must be identical. Otherwise, a different `VkPipelineColorBlendAttachmentState` can be provided for each bound color attachment.

- `geometryShader` specifies whether geometry shaders are supported. If this feature is not enabled, the `VK_SHADER_STAGE_GEOMETRY_BIT` and `VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT` enum values must not be used. This also specifies whether shader modules can declare the `Geometry` capability.

- `tessellationShader` specifies whether tessellation control and evaluation shaders are supported. If this feature is not enabled, the `VK_SHADER_STAGE_TESSELLATION_CONTROL_BIT`, `VK_SHADER_STAGE_TESSELLATION_EVALUATION_BIT`, `VK_PIPELINE_STAGE_TESSELLATION_CONTROL_SHADER_BIT`, `VK_PIPELINE_STAGE_TESSELLATION_EVALUATION_SHADER_BIT`, and `VK_STRUCTURE_TYPE_PIPELINE_TESSELLATION_STATE_CREATE_INFO` enum values must not be used. This also specifies whether shader modules can declare the `Tessellation` capability.

- `sampleRateShading` specifies whether Sample Shading and multisample interpolation are supported. If this feature is not enabled, the `sampleShadingEnable` member of the `VkPipelineMultisampleStateCreateInfo` structure must be set to `VK_FALSE` and the `minSampleShading` member is ignored. This also specifies whether shader modules can declare the `SampleRateShading` capability.

- `dualSrcBlend` specifies whether blend operations which take two sources are supported. If this feature is not enabled, the `VK_BLEND_FACTOR_SRC1_COLOR`, `VK_BLEND_FACTOR_ONE_MINUS_SRC1_COLOR`, `VK_BLEND_FACTOR_SRC1_ALPHA`, and `VK_BLEND_FACTOR_ONE_MINUS_SRC1_ALPHA` enum values must not be used as source or destination blending factors. See Dual-Source Blending.

- `logicOp` specifies whether logic operations are supported. If this feature is not enabled, the `logicOpEnable` member of the `VkPipelineColorBlendStateCreateInfo` structure must be set to `VK_FALSE`, and the `logicOp` member is ignored.

- `multiDrawIndirect` specifies whether multiple draw indirect is supported. If this feature is not enabled, the `drawCount` parameter to the `vkCmdDrawIndirect` and `vkCmdDrawIndexedIndirect` commands must be 0 or 1. The `maxDrawIndirectCount` member of the `VkPhysicalDeviceLimits` structure must also be 1 if this feature is not supported. See maxDrawIndirectCount.

- `drawIndirectFirstInstance` specifies whether indirect draw calls support the `firstInstance` parameter. If this feature is not enabled, the `firstInstance` member of all `VkDrawIndirectCommand` and `VkDrawIndexedIndirectCommand` structures that are provided to the `vkCmdDrawIndirect` and `vkCmdDrawIndexedIndirect` commands must be 0.

- `depthClamp` specifies whether depth clamping is supported. If this feature is not enabled, the `depthClampEnable` member of the `VkPipelineRasterizationStateCreateInfo` structure must be set to `VK_FALSE`. Otherwise, setting `depthClampEnable` to `VK_TRUE` will enable depth clamping.

- `depthBiasClamp` specifies whether depth bias clamping is supported. If this feature is not enabled, the `depthBiasClamp` member of the `VkPipelineRasterizationStateCreateInfo` structure must be set to 0.0 unless the `VK_DYNAMIC_STATE_DEPTH_BIAS` dynamic state is enabled, and the `depthBiasClamp` parameter to `vkCmdSetDepthBias` must be set to 0.0.

- `fillModeNonSolid` specifies whether point and wireframe fill modes are supported. If this feature is not enabled, the `VK_POLYGON_MODE_POINT` and `VK_POLYGON_MODE_LINE` enum values must not be used.

- `depthBounds` specifies whether depth bounds tests are supported. If this feature is not enabled, the `depthBoundsTestEnable` member of the `VkPipelineDepthStencilStateCreateInfo` structure must be set to `VK_FALSE`. When `depthBoundsTestEnable` is set to `VK_FALSE`, the `minDepthBounds` and `maxDepthBounds` members of the `VkPipelineDepthStencilStateCreateInfo` structure are ignored.

- `wideLines` specifies whether lines with width other than 1.0 are supported. If this feature is not enabled, the `lineWidth` member of the `VkPipelineRasterizationStateCreateInfo` structure must be set to 1.0 unless the `VK_DYNAMIC_STATE_LINE_WIDTH` dynamic state is enabled, and the `lineWidth` parameter to `vkCmdSetLineWidth` must be set to 1.0. When this feature is supported, the range and granularity of supported line widths are indicated by the `lineWidthRange` and `lineWidthGranularity` members of the `VkPhysicalDeviceLimits` structure, respectively.

- `largePoints` specifies whether points with size greater than 1.0 are supported. If this feature is not enabled, only a point size of 1.0 written by a shader is supported. The range and granularity of supported point sizes are indicated by the `pointSizeRange` and `pointSizeGranularity` members of the `VkPhysicalDeviceLimits` structure, respectively.

- `alphaToOne` specifies whether the implementation is able to replace the alpha value of the color fragment output from the fragment shader with the maximum representable alpha value for fixed-point colors or 1.0 for floating-point colors. If this feature is not enabled, then the `alphaToOneEnable` member of the `VkPipelineMultisampleStateCreateInfo` structure must be set to `VK_FALSE`. Otherwise setting `alphaToOneEnable` to `VK_TRUE` will enable alpha-to-one behavior.

- `multiViewport` specifies whether more than one viewport is supported. If this feature is not enabled:

  - The `viewportCount` and `scissorCount` members of the `VkPipelineViewportStateCreateInfo` structure must be set to 1.

  - The `firstViewport` and `viewportCount` parameters to the `vkCmdSetViewport` command must be set to 0 and 1, respectively.

  - The `firstScissor` and `scissorCount` parameters to the `vkCmdSetScissor` command must be set to 0 and 1, respectively.

  - The `exclusiveScissorCount` member of the `VkPipelineViewportExclusiveScissorStateCreateInfoNV` structure must be set to 0 or 1.

  - The `firstExclusiveScissor` and `exclusiveScissorCount` parameters to the `vkCmdSetExclusiveScissorNV` command must be set to 0 and 1, respectively.

- `samplerAnisotropy` specifies whether anisotropic filtering is supported. If this feature is not enabled, the `anisotropyEnable` member of the `VkSamplerCreateInfo` structure must be `VK_FALSE`.

- `textureCompressionETC2` specifies whether all of the ETC2 and EAC compressed texture formats are supported. If this feature is enabled, then the `VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT`, `VK_FORMAT_FEATURE_BLIT_SRC_BIT` and `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT` features must be supported in `optimalTilingFeatures` for the following formats:

  - `VK_FORMAT_ETC2_R8G8B8_UNORM_BLOCK`

  - `VK_FORMAT_ETC2_R8G8B8_SRGB_BLOCK`

  - `VK_FORMAT_ETC2_R8G8B8A1_UNORM_BLOCK`

  - `VK_FORMAT_ETC2_R8G8B8A1_SRGB_BLOCK`

  - `VK_FORMAT_ETC2_R8G8B8A8_UNORM_BLOCK`

  - `VK_FORMAT_ETC2_R8G8B8A8_SRGB_BLOCK`

  - `VK_FORMAT_EAC_R11_UNORM_BLOCK`

  - `VK_FORMAT_EAC_R11_SNORM_BLOCK`

  - `VK_FORMAT_EAC_R11G11_UNORM_BLOCK`

  - `VK_FORMAT_EAC_R11G11_SNORM_BLOCK`

  To query for additional properties, or if the feature is not enabled, vkGetPhysicalDeviceFormatProperties and vkGetPhysicalDeviceImageFormatProperties can be used to check for supported properties of individual formats as normal.

- `textureCompressionASTC_LDR` specifies whether all of the ASTC LDR compressed texture formats are supported. If this feature is enabled, then the `VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT`, `VK_FORMAT_FEATURE_BLIT_SRC_BIT` and `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT` features must be supported in `optimalTilingFeatures` for the following formats:

  - `VK_FORMAT_ASTC_4x4_UNORM_BLOCK`

  - `VK_FORMAT_ASTC_4x4_SRGB_BLOCK`

  - `VK_FORMAT_ASTC_5x4_UNORM_BLOCK`

  - `VK_FORMAT_ASTC_5x4_SRGB_BLOCK`

  - `VK_FORMAT_ASTC_5x5_UNORM_BLOCK`

  - `VK_FORMAT_ASTC_5x5_SRGB_BLOCK`

  - `VK_FORMAT_ASTC_6x5_UNORM_BLOCK`

  - `VK_FORMAT_ASTC_6x5_SRGB_BLOCK`

  - `VK_FORMAT_ASTC_6x6_UNORM_BLOCK`

  - `VK_FORMAT_ASTC_6x6_SRGB_BLOCK`

  - `VK_FORMAT_ASTC_8x5_UNORM_BLOCK`

  - `VK_FORMAT_ASTC_8x5_SRGB_BLOCK`

  - `VK_FORMAT_ASTC_8x6_UNORM_BLOCK`

  - `VK_FORMAT_ASTC_8x6_SRGB_BLOCK`

  - `VK_FORMAT_ASTC_8x8_UNORM_BLOCK`

  - `VK_FORMAT_ASTC_8x8_SRGB_BLOCK`

  - `VK_FORMAT_ASTC_10x5_UNORM_BLOCK`

  - `VK_FORMAT_ASTC_10x5_SRGB_BLOCK`

  - `VK_FORMAT_ASTC_10x6_UNORM_BLOCK`

  - `VK_FORMAT_ASTC_10x6_SRGB_BLOCK`

  - `VK_FORMAT_ASTC_10x8_UNORM_BLOCK`

  - `VK_FORMAT_ASTC_10x8_SRGB_BLOCK`

  - `VK_FORMAT_ASTC_10x10_UNORM_BLOCK`

  - `VK_FORMAT_ASTC_10x10_SRGB_BLOCK`

  - `VK_FORMAT_ASTC_12x10_UNORM_BLOCK`

  - `VK_FORMAT_ASTC_12x10_SRGB_BLOCK`

  - `VK_FORMAT_ASTC_12x12_UNORM_BLOCK`

  - `VK_FORMAT_ASTC_12x12_SRGB_BLOCK`

  To query for additional properties, or if the feature is not enabled, vkGetPhysicalDeviceFormatProperties and vkGetPhysicalDeviceImageFormatProperties can be used to check for supported properties of individual formats as normal.

- `textureCompressionBC` specifies whether all of the BC compressed texture formats are supported. If this feature is enabled, then the `VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT`, `VK_FORMAT_FEATURE_BLIT_SRC_BIT` and `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT` features must be supported in `optimalTilingFeatures` for the following formats:

  - `VK_FORMAT_BC1_RGB_UNORM_BLOCK`

  - `VK_FORMAT_BC1_RGB_SRGB_BLOCK`

  - `VK_FORMAT_BC1_RGBA_UNORM_BLOCK`

  - `VK_FORMAT_BC1_RGBA_SRGB_BLOCK`

  - `VK_FORMAT_BC2_UNORM_BLOCK`

  - `VK_FORMAT_BC2_SRGB_BLOCK`

  - `VK_FORMAT_BC3_UNORM_BLOCK`

  - `VK_FORMAT_BC3_SRGB_BLOCK`

  - `VK_FORMAT_BC4_UNORM_BLOCK`

  - `VK_FORMAT_BC4_SNORM_BLOCK`

  - `VK_FORMAT_BC5_UNORM_BLOCK`

  - `VK_FORMAT_BC5_SNORM_BLOCK`

  - `VK_FORMAT_BC6H_UFLOAT_BLOCK`

  - `VK_FORMAT_BC6H_SFLOAT_BLOCK`

  - `VK_FORMAT_BC7_UNORM_BLOCK`

  - `VK_FORMAT_BC7_SRGB_BLOCK`

  To query for additional properties, or if the feature is not enabled, vkGetPhysicalDeviceFormatProperties and vkGetPhysicalDeviceImageFormatProperties can be used to check for supported properties of individual formats as normal.

- `occlusionQueryPrecise` specifies whether occlusion queries returning actual sample counts are supported. Occlusion queries are created in a `VkQueryPool` by specifying the `queryType` of `VK_QUERY_TYPE_OCCLUSION` in the `VkQueryPoolCreateInfo` structure which is passed to `vkCreateQueryPool`. If this feature is enabled, queries of this type can enable `VK_QUERY_CONTROL_PRECISE_BIT` in the `flags` parameter to `vkCmdBeginQuery`. If this feature is not supported, the implementation supports only boolean occlusion queries. When any samples are passed, boolean queries will return a non-zero result value, otherwise a result value of zero is returned. When this feature is enabled and `VK_QUERY_CONTROL_PRECISE_BIT` is set, occlusion queries will report the actual number of samples passed.

- `pipelineStatisticsQuery` specifies whether the pipeline statistics queries are supported. If this feature is not enabled, queries of type `VK_QUERY_TYPE_PIPELINE_STATISTICS` cannot be created, and none of the VkQueryPipelineStatisticFlagBits bits can be set in the `pipelineStatistics` member of the `VkQueryPoolCreateInfo` structure.

- `vertexPipelineStoresAndAtomics` specifies whether storage buffers and images support stores and atomic operations in the vertex, tessellation, and geometry shader stages. If this feature is not enabled, all storage image, storage texel buffers, and storage buffer variables used by these stages in shader modules must be decorated with the `NonWritable` decoration (or the `readonly` memory qualifier in GLSL).

- `fragmentStoresAndAtomics` specifies whether storage buffers and images support stores and atomic operations in the fragment shader stage. If this feature is not enabled, all storage image, storage texel buffers, and storage buffer variables used by the fragment stage in shader modules must be decorated with the `NonWritable` decoration (or the `readonly` memory qualifier in GLSL).

- `shaderTessellationAndGeometryPointSize` specifies whether the `PointSize` built-in decoration is available in the tessellation control, tessellation evaluation, and geometry shader stages. If this feature is not enabled, members decorated with the `PointSize` built-in decoration must not be read from or written to and all points written from a tessellation or geometry shader will have a size of 1.0. This also specifies whether shader modules can declare the `TessellationPointSize` capability for tessellation control and evaluation shaders, or if the shader modules can declare the `GeometryPointSize` capability for geometry shaders. An implementation supporting this feature must also support one or both of the `tessellationShader` or `geometryShader` features.

- `shaderImageGatherExtended` specifies whether the extended set of image gather instructions are available in shader code. If this feature is not enabled, the `OpImage`*`Gather` instructions do not support the `Offset` and `ConstOffsets` operands. This also specifies whether shader modules can declare the `ImageGatherExtended` capability.

- `shaderStorageImageExtendedFormats` specifies whether all the “storage image extended formats” below are supported; if this feature is supported, then the `VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT` must be supported in `optimalTilingFeatures` for the following formats:

  - `VK_FORMAT_R16G16_SFLOAT`

  - `VK_FORMAT_B10G11R11_UFLOAT_PACK32`

  - `VK_FORMAT_R16_SFLOAT`

  - `VK_FORMAT_R16G16B16A16_UNORM`

  - `VK_FORMAT_A2B10G10R10_UNORM_PACK32`

  - `VK_FORMAT_R16G16_UNORM`

  - `VK_FORMAT_R8G8_UNORM`

  - `VK_FORMAT_R16_UNORM`

  - `VK_FORMAT_R8_UNORM`

  - `VK_FORMAT_R16G16B16A16_SNORM`

  - `VK_FORMAT_R16G16_SNORM`

  - `VK_FORMAT_R8G8_SNORM`

  - `VK_FORMAT_R16_SNORM`

  - `VK_FORMAT_R8_SNORM`

  - `VK_FORMAT_R16G16_SINT`

  - `VK_FORMAT_R8G8_SINT`

  - `VK_FORMAT_R16_SINT`

  - `VK_FORMAT_R8_SINT`

  - `VK_FORMAT_A2B10G10R10_UINT_PACK32`

  - `VK_FORMAT_R16G16_UINT`

  - `VK_FORMAT_R8G8_UINT`

  - `VK_FORMAT_R16_UINT`

  - `VK_FORMAT_R8_UINT`

  | Note `shaderStorageImageExtendedFormats` feature only adds a guarantee of format support, which is specified for the whole physical device. Therefore enabling or disabling the feature via vkCreateDevice has no practical effect. To query for additional properties, or if the feature is not supported, vkGetPhysicalDeviceFormatProperties and vkGetPhysicalDeviceImageFormatProperties can be used to check for supported properties of individual formats, as usual rules allow. `VK_FORMAT_R32G32_UINT`, `VK_FORMAT_R32G32_SINT`, and `VK_FORMAT_R32G32_SFLOAT` from `StorageImageExtendedFormats` SPIR-V capability, are already covered by core Vulkan mandatory format support.

- `shaderStorageImageMultisample` specifies whether multisampled storage images are supported. If this feature is not enabled, images that are created with a `usage` that includes `VK_IMAGE_USAGE_STORAGE_BIT` must be created with `samples` equal to `VK_SAMPLE_COUNT_1_BIT`. This also specifies whether shader modules can declare the `StorageImageMultisample` capability.

- `shaderStorageImageReadWithoutFormat` specifies whether storage images require a format qualifier to be specified when reading from storage images. If this feature is not enabled, the `OpImageRead` instruction must not have an `OpTypeImage` of `Unknown`. This also specifies whether shader modules can declare the `StorageImageReadWithoutFormat` capability.

- `shaderStorageImageWriteWithoutFormat` specifies whether storage images require a format qualifier to be specified when writing to storage images. If this feature is not enabled, the `OpImageWrite` instruction must not have an `OpTypeImage` of `Unknown`. This also specifies whether shader modules can declare the `StorageImageWriteWithoutFormat` capability.

- `shaderUniformBufferArrayDynamicIndexing` specifies whether arrays of uniform buffers can be indexed by dynamically uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER` or `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC` must be indexed only by constant integral expressions when aggregated into arrays in shader code. This also specifies whether shader modules can declare the `UniformBufferArrayDynamicIndexing` capability.

- `shaderSampledImageArrayDynamicIndexing` specifies whether arrays of samplers or sampled images can be indexed by dynamically uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_SAMPLER`, `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, or `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE` must be indexed only by constant integral expressions when aggregated into arrays in shader code. This also specifies whether shader modules can declare the `SampledImageArrayDynamicIndexing` capability.

- `shaderStorageBufferArrayDynamicIndexing` specifies whether arrays of storage buffers can be indexed by dynamically uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER` or `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC` must be indexed only by constant integral expressions when aggregated into arrays in shader code. This also specifies whether shader modules can declare the `StorageBufferArrayDynamicIndexing` capability.

- `shaderStorageImageArrayDynamicIndexing` specifies whether arrays of storage images can be indexed by dynamically uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE` must be indexed only by constant integral expressions when aggregated into arrays in shader code. This also specifies whether shader modules can declare the `StorageImageArrayDynamicIndexing` capability.

- `shaderClipDistance` specifies whether clip distances are supported in shader code. If this feature is not enabled, any members decorated with the `ClipDistance` built-in decoration must not be read from or written to in shader modules. This also specifies whether shader modules can declare the `ClipDistance` capability.

- `shaderCullDistance` specifies whether cull distances are supported in shader code. If this feature is not enabled, any members decorated with the `CullDistance` built-in decoration must not be read from or written to in shader modules. This also specifies whether shader modules can declare the `CullDistance` capability.

- `shaderFloat64` specifies whether 64-bit floats (doubles) are supported in shader code. If this feature is not enabled, 64-bit floating-point types must not be used in shader code. This also specifies whether shader modules can declare the `Float64` capability. Declaring and using 64-bit floats is enabled for all storage classes that SPIR-V allows with the `Float64` capability.

- `shaderInt64` specifies whether 64-bit integers (signed and unsigned) are supported in shader code. If this feature is not enabled, 64-bit integer types must not be used in shader code. This also specifies whether shader modules can declare the `Int64` capability. Declaring and using 64-bit integers is enabled for all storage classes that SPIR-V allows with the `Int64` capability.

- `shaderInt16` specifies whether 16-bit integers (signed and unsigned) are supported in shader code. If this feature is not enabled, 16-bit integer types must not be used in shader code. This also specifies whether shader modules can declare the `Int16` capability. However, this only enables a subset of the storage classes that SPIR-V allows for the `Int16` SPIR-V capability: Declaring and using 16-bit integers in the `Private`, `Workgroup`, and `Function` storage classes is enabled, while declaring them in the interface storage classes (e.g., `UniformConstant`, `Uniform`, `StorageBuffer`, `Input`, `Output`, and `PushConstant`) is not enabled.

- `shaderResourceResidency` specifies whether image operations that return resource residency information are supported in shader code. If this feature is not enabled, the `OpImageSparse`* instructions must not be used in shader code. This also specifies whether shader modules can declare the `SparseResidency` capability. The feature requires at least one of the `sparseResidency*` features to be supported.

- `shaderResourceMinLod` specifies whether image operations specifying the minimum resource LOD are supported in shader code. If this feature is not enabled, the `MinLod` image operand must not be used in shader code. This also specifies whether shader modules can declare the `MinLod` capability.

- `sparseBinding` specifies whether resource memory can be managed at opaque sparse block level instead of at the object level. If this feature is not enabled, resource memory must be bound only on a per-object basis using the `vkBindBufferMemory` and `vkBindImageMemory` commands. In this case, buffers and images must not be created with `VK_BUFFER_CREATE_SPARSE_BINDING_BIT` and `VK_IMAGE_CREATE_SPARSE_BINDING_BIT` set in the `flags` member of the `VkBufferCreateInfo` and `VkImageCreateInfo` structures, respectively. Otherwise resource memory can be managed as described in Sparse Resource Features.

- `sparseResidencyBuffer` specifies whether the device can access partially resident buffers. If this feature is not enabled, buffers must not be created with `VK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT` set in the `flags` member of the `VkBufferCreateInfo` structure.

- `sparseResidencyImage2D` specifies whether the device can access partially resident 2D images with 1 sample per pixel. If this feature is not enabled, images with an `imageType` of `VK_IMAGE_TYPE_2D` and `samples` set to `VK_SAMPLE_COUNT_1_BIT` must not be created with `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT` set in the `flags` member of the `VkImageCreateInfo` structure.

- `sparseResidencyImage3D` specifies whether the device can access partially resident 3D images. If this feature is not enabled, images with an `imageType` of `VK_IMAGE_TYPE_3D` must not be created with `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT` set in the `flags` member of the `VkImageCreateInfo` structure.

- `sparseResidency2Samples` specifies whether the physical device can access partially resident 2D images with 2 samples per pixel. If this feature is not enabled, images with an `imageType` of `VK_IMAGE_TYPE_2D` and `samples` set to `VK_SAMPLE_COUNT_2_BIT` must not be created with `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT` set in the `flags` member of the `VkImageCreateInfo` structure.

- `sparseResidency4Samples` specifies whether the physical device can access partially resident 2D images with 4 samples per pixel. If this feature is not enabled, images with an `imageType` of `VK_IMAGE_TYPE_2D` and `samples` set to `VK_SAMPLE_COUNT_4_BIT` must not be created with `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT` set in the `flags` member of the `VkImageCreateInfo` structure.

- `sparseResidency8Samples` specifies whether the physical device can access partially resident 2D images with 8 samples per pixel. If this feature is not enabled, images with an `imageType` of `VK_IMAGE_TYPE_2D` and `samples` set to `VK_SAMPLE_COUNT_8_BIT` must not be created with `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT` set in the `flags` member of the `VkImageCreateInfo` structure.

- `sparseResidency16Samples` specifies whether the physical device can access partially resident 2D images with 16 samples per pixel. If this feature is not enabled, images with an `imageType` of `VK_IMAGE_TYPE_2D` and `samples` set to `VK_SAMPLE_COUNT_16_BIT` must not be created with `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT` set in the `flags` member of the `VkImageCreateInfo` structure.

- `sparseResidencyAliased` specifies whether the physical device can correctly access data aliased into multiple locations. If this feature is not enabled, the `VK_BUFFER_CREATE_SPARSE_ALIASED_BIT` and `VK_IMAGE_CREATE_SPARSE_ALIASED_BIT` enum values must not be used in `flags` members of the `VkBufferCreateInfo` and `VkImageCreateInfo` structures, respectively.

- `variableMultisampleRate` specifies whether all pipelines that will be bound to a command buffer during a subpass with no attachments must have the same value for `VkPipelineMultisampleStateCreateInfo`::`rasterizationSamples`. If set to `VK_TRUE`, the implementation supports variable multisample rates in a subpass with no attachments. If set to `VK_FALSE`, then all pipelines bound in such a subpass must have the same multisample rate. This has no effect in situations where a subpass uses any attachments.

- `inheritedQueries` specifies whether a secondary command buffer may be executed while a query is active.

The `VkPhysicalDeviceVulkan11Features` structure is defined as:

    typedef struct VkPhysicalDeviceVulkan11Features {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           storageBuffer16BitAccess;
        VkBool32           uniformAndStorageBuffer16BitAccess;
        VkBool32           storagePushConstant16;
        VkBool32           storageInputOutput16;
        VkBool32           multiview;
        VkBool32           multiviewGeometryShader;
        VkBool32           multiviewTessellationShader;
        VkBool32           variablePointersStorageBuffer;
        VkBool32           variablePointers;
        VkBool32           protectedMemory;
        VkBool32           samplerYcbcrConversion;
        VkBool32           shaderDrawParameters;
    } VkPhysicalDeviceVulkan11Features;

The members of the `VkPhysicalDeviceVulkan11Features` structure describe the following features:

- `storageBuffer16BitAccess` specifies whether objects in the `StorageBuffer` or `PhysicalStorageBuffer` storage class with the `Block` decoration can have 16-bit integer and 16-bit floating-point members. If this feature is not enabled, 16-bit integer or 16-bit floating-point members must not be used in such objects. This also specifies whether shader modules can declare the `StorageBuffer16BitAccess` capability.

- `uniformAndStorageBuffer16BitAccess` specifies whether objects in the `Uniform` storage class with the `Block` decoration and in the `StorageBuffer` or `PhysicalStorageBuffer` storage class with the same decoration can have 16-bit integer and 16-bit floating-point members. If this feature is not enabled, 16-bit integer or 16-bit floating-point members must not be used in such objects. This also specifies whether shader modules can declare the `UniformAndStorageBuffer16BitAccess` capability.

- `storagePushConstant16` specifies whether objects in the `PushConstant` storage class can have 16-bit integer and 16-bit floating-point members. If this feature is not enabled, 16-bit integer or floating-point members must not be used in such objects. This also specifies whether shader modules can declare the `StoragePushConstant16` capability.

- `storageInputOutput16` specifies whether objects in the `Input` and `Output` storage classes can have 16-bit integer and 16-bit floating-point members. If this feature is not enabled, 16-bit integer or 16-bit floating-point members must not be used in such objects. This also specifies whether shader modules can declare the `StorageInputOutput16` capability.

- `multiview` specifies whether the implementation supports multiview rendering within a render pass. If this feature is not enabled, the view mask of each subpass must always be zero.

- `multiviewGeometryShader` specifies whether the implementation supports multiview rendering within a render pass, with geometry shaders. If this feature is not enabled, then a pipeline compiled against a subpass with a non-zero view mask must not include a geometry shader.

- `multiviewTessellationShader` specifies whether the implementation supports multiview rendering within a render pass, with tessellation shaders. If this feature is not enabled, then a pipeline compiled against a subpass with a non-zero view mask must not include any tessellation shaders.

- `variablePointersStorageBuffer` specifies whether the implementation supports the SPIR-V `VariablePointersStorageBuffer` capability. When this feature is not enabled, shader modules must not declare the `SPV_KHR_variable_pointers` extension or the `VariablePointersStorageBuffer` capability.

- `variablePointers` specifies whether the implementation supports the SPIR-V `VariablePointers` capability. When this feature is not enabled, shader modules must not declare the `VariablePointers` capability.

- `protectedMemory` specifies whether protected memory is supported.

- `samplerYcbcrConversion` specifies whether the implementation supports sampler Y′CBCR conversion. If `samplerYcbcrConversion` is `VK_FALSE`, sampler Y′CBCR conversion is not supported, and samplers using sampler Y′CBCR conversion must not be used.

- `shaderDrawParameters` specifies whether shader draw parameters are supported.

If the `VkPhysicalDeviceVulkan11Features` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether each feature is supported. `VkPhysicalDeviceVulkan11Features` can also be used in the `pNext` chain of VkDeviceCreateInfo to enable the features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VULKAN_1_1_FEATURES`

The `VkPhysicalDeviceVulkan12Features` structure is defined as:

    typedef struct VkPhysicalDeviceVulkan12Features {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           samplerMirrorClampToEdge;
        VkBool32           drawIndirectCount;
        VkBool32           storageBuffer8BitAccess;
        VkBool32           uniformAndStorageBuffer8BitAccess;
        VkBool32           storagePushConstant8;
        VkBool32           shaderBufferInt64Atomics;
        VkBool32           shaderSharedInt64Atomics;
        VkBool32           shaderFloat16;
        VkBool32           shaderInt8;
        VkBool32           descriptorIndexing;
        VkBool32           shaderInputAttachmentArrayDynamicIndexing;
        VkBool32           shaderUniformTexelBufferArrayDynamicIndexing;
        VkBool32           shaderStorageTexelBufferArrayDynamicIndexing;
        VkBool32           shaderUniformBufferArrayNonUniformIndexing;
        VkBool32           shaderSampledImageArrayNonUniformIndexing;
        VkBool32           shaderStorageBufferArrayNonUniformIndexing;
        VkBool32           shaderStorageImageArrayNonUniformIndexing;
        VkBool32           shaderInputAttachmentArrayNonUniformIndexing;
        VkBool32           shaderUniformTexelBufferArrayNonUniformIndexing;
        VkBool32           shaderStorageTexelBufferArrayNonUniformIndexing;
        VkBool32           descriptorBindingUniformBufferUpdateAfterBind;
        VkBool32           descriptorBindingSampledImageUpdateAfterBind;
        VkBool32           descriptorBindingStorageImageUpdateAfterBind;
        VkBool32           descriptorBindingStorageBufferUpdateAfterBind;
        VkBool32           descriptorBindingUniformTexelBufferUpdateAfterBind;
        VkBool32           descriptorBindingStorageTexelBufferUpdateAfterBind;
        VkBool32           descriptorBindingUpdateUnusedWhilePending;
        VkBool32           descriptorBindingPartiallyBound;
        VkBool32           descriptorBindingVariableDescriptorCount;
        VkBool32           runtimeDescriptorArray;
        VkBool32           samplerFilterMinmax;
        VkBool32           scalarBlockLayout;
        VkBool32           imagelessFramebuffer;
        VkBool32           uniformBufferStandardLayout;
        VkBool32           shaderSubgroupExtendedTypes;
        VkBool32           separateDepthStencilLayouts;
        VkBool32           hostQueryReset;
        VkBool32           timelineSemaphore;
        VkBool32           bufferDeviceAddress;
        VkBool32           bufferDeviceAddressCaptureReplay;
        VkBool32           bufferDeviceAddressMultiDevice;
        VkBool32           vulkanMemoryModel;
        VkBool32           vulkanMemoryModelDeviceScope;
        VkBool32           vulkanMemoryModelAvailabilityVisibilityChains;
        VkBool32           shaderOutputViewportIndex;
        VkBool32           shaderOutputLayer;
        VkBool32           subgroupBroadcastDynamicId;
    } VkPhysicalDeviceVulkan12Features;

The members of the `VkPhysicalDeviceVulkan12Features` structure describe the following features:

- `samplerMirrorClampToEdge` indicates whether the implementation supports the `VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE` sampler address mode. If this feature is not enabled, the `VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE` sampler address mode must not be used.

- `drawIndirectCount` indicates whether the implementation supports the vkCmdDrawIndirectCount and vkCmdDrawIndexedIndirectCount functions. If this feature is not enabled, these functions must not be used.

- `storageBuffer8BitAccess` indicates whether objects in the `StorageBuffer` or `PhysicalStorageBuffer` storage class with the `Block` decoration can have 8-bit integer members. If this feature is not enabled, 8-bit integer members must not be used in such objects. This also indicates whether shader modules can declare the `StorageBuffer8BitAccess` capability.

- `uniformAndStorageBuffer8BitAccess` indicates whether objects in the `Uniform` storage class with the `Block` decoration and in the `StorageBuffer` or `PhysicalStorageBuffer` storage class with the same decoration can have 8-bit integer members. If this feature is not enabled, 8-bit integer members must not be used in such objects. This also indicates whether shader modules can declare the `UniformAndStorageBuffer8BitAccess` capability.

- `storagePushConstant8` indicates whether objects in the `PushConstant` storage class can have 8-bit integer members. If this feature is not enabled, 8-bit integer members must not be used in such objects. This also indicates whether shader modules can declare the `StoragePushConstant8` capability.

- `shaderBufferInt64Atomics` indicates whether shaders can support 64-bit unsigned and signed integer atomic operations on buffers.

- `shaderSharedInt64Atomics` indicates whether shaders can support 64-bit unsigned and signed integer atomic operations on shared memory.

- `shaderFloat16` indicates whether 16-bit floats (halfs) are supported in shader code. This also indicates whether shader modules can declare the `Float16` capability. However, this only enables a subset of the storage classes that SPIR-V allows for the `Float16` SPIR-V capability: Declaring and using 16-bit floats in the `Private`, `Workgroup`, and `Function` storage classes is enabled, while declaring them in the interface storage classes (e.g., `UniformConstant`, `Uniform`, `StorageBuffer`, `Input`, `Output`, and `PushConstant`) is not enabled.

- `shaderInt8` indicates whether 8-bit integers (signed and unsigned) are supported in shader code. This also indicates whether shader modules can declare the `Int8` capability. However, this only enables a subset of the storage classes that SPIR-V allows for the `Int8` SPIR-V capability: Declaring and using 8-bit integers in the `Private`, `Workgroup`, and `Function` storage classes is enabled, while declaring them in the interface storage classes (e.g., `UniformConstant`, `Uniform`, `StorageBuffer`, `Input`, `Output`, and `PushConstant`) is not enabled.

- `descriptorIndexing` indicates whether the implementation supports the minimum set of descriptor indexing features as described in the Feature Requirements section. Enabling the `descriptorIndexing` member when vkCreateDevice is called does not imply the other minimum descriptor indexing features are also enabled. Those other descriptor indexing features must be enabled individually as needed by the application.

- `shaderInputAttachmentArrayDynamicIndexing` indicates whether arrays of input attachments can be indexed by dynamically uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT` must be indexed only by constant integral expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare the `InputAttachmentArrayDynamicIndexing` capability.

- `shaderUniformTexelBufferArrayDynamicIndexing` indicates whether arrays of uniform texel buffers can be indexed by dynamically uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER` must be indexed only by constant integral expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare the `UniformTexelBufferArrayDynamicIndexing` capability.

- `shaderStorageTexelBufferArrayDynamicIndexing` indicates whether arrays of storage texel buffers can be indexed by dynamically uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER` must be indexed only by constant integral expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare the `StorageTexelBufferArrayDynamicIndexing` capability.

- `shaderUniformBufferArrayNonUniformIndexing` indicates whether arrays of uniform buffers can be indexed by non-uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER` or `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC` must not be indexed by non-uniform integer expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare the `UniformBufferArrayNonUniformIndexing` capability.

- `shaderSampledImageArrayNonUniformIndexing` indicates whether arrays of samplers or sampled images can be indexed by non-uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_SAMPLER`, `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, or `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE` must not be indexed by non-uniform integer expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare the `SampledImageArrayNonUniformIndexing` capability.

- `shaderStorageBufferArrayNonUniformIndexing` indicates whether arrays of storage buffers can be indexed by non-uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER` or `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC` must not be indexed by non-uniform integer expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare the `StorageBufferArrayNonUniformIndexing` capability.

- `shaderStorageImageArrayNonUniformIndexing` indicates whether arrays of storage images can be indexed by non-uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE` must not be indexed by non-uniform integer expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare the `StorageImageArrayNonUniformIndexing` capability.

- `shaderInputAttachmentArrayNonUniformIndexing` indicates whether arrays of input attachments can be indexed by non-uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT` must not be indexed by non-uniform integer expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare the `InputAttachmentArrayNonUniformIndexing` capability.

- `shaderUniformTexelBufferArrayNonUniformIndexing` indicates whether arrays of uniform texel buffers can be indexed by non-uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER` must not be indexed by non-uniform integer expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare the `UniformTexelBufferArrayNonUniformIndexing` capability.

- `shaderStorageTexelBufferArrayNonUniformIndexing` indicates whether arrays of storage texel buffers can be indexed by non-uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER` must not be indexed by non-uniform integer expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare the `StorageTexelBufferArrayNonUniformIndexing` capability.

- `descriptorBindingUniformBufferUpdateAfterBind` indicates whether the implementation supports updating uniform buffer descriptors after a set is bound. If this feature is not enabled, `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT` must not be used with `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER`.

- `descriptorBindingSampledImageUpdateAfterBind` indicates whether the implementation supports updating sampled image descriptors after a set is bound. If this feature is not enabled, `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT` must not be used with `VK_DESCRIPTOR_TYPE_SAMPLER`, `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, or `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE`.

- `descriptorBindingStorageImageUpdateAfterBind` indicates whether the implementation supports updating storage image descriptors after a set is bound. If this feature is not enabled, `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT` must not be used with `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE`.

- `descriptorBindingStorageBufferUpdateAfterBind` indicates whether the implementation supports updating storage buffer descriptors after a set is bound. If this feature is not enabled, `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT` must not be used with `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER`.

- `descriptorBindingUniformTexelBufferUpdateAfterBind` indicates whether the implementation supports updating uniform texel buffer descriptors after a set is bound. If this feature is not enabled, `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT` must not be used with `VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER`.

- `descriptorBindingStorageTexelBufferUpdateAfterBind` indicates whether the implementation supports updating storage texel buffer descriptors after a set is bound. If this feature is not enabled, `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT` must not be used with `VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER`.

- `descriptorBindingUpdateUnusedWhilePending` indicates whether the implementation supports updating descriptors while the set is in use. If this feature is not enabled, `VK_DESCRIPTOR_BINDING_UPDATE_UNUSED_WHILE_PENDING_BIT` must not be used.

- `descriptorBindingPartiallyBound` indicates whether the implementation supports statically using a descriptor set binding in which some descriptors are not valid. If this feature is not enabled, `VK_DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT` must not be used.

- `descriptorBindingVariableDescriptorCount` indicates whether the implementation supports descriptor sets with a variable-sized last binding. If this feature is not enabled, `VK_DESCRIPTOR_BINDING_VARIABLE_DESCRIPTOR_COUNT_BIT` must not be used.

- `runtimeDescriptorArray` indicates whether the implementation supports the SPIR-V `RuntimeDescriptorArray` capability. If this feature is not enabled, descriptors must not be declared in runtime arrays.

- `samplerFilterMinmax` indicates whether the implementation supports a minimum set of required formats supporting min/max filtering as defined by the `filterMinmaxSingleComponentFormats` property minimum requirements. If this feature is not enabled, then no VkSamplerCreateInfo `pNext` chain can include a VkSamplerReductionModeCreateInfo structure.

- `scalarBlockLayout` indicates that the implementation supports the layout of resource blocks in shaders using scalar alignment.

- `imagelessFramebuffer` indicates that the implementation supports specifying the image view for attachments at render pass begin time via VkRenderPassAttachmentBeginInfo.

- `uniformBufferStandardLayout` indicates that the implementation supports the same layouts for uniform buffers as for storage and other kinds of buffers. See Standard Buffer Layout.

- `shaderSubgroupExtendedTypes` is a boolean that specifies whether subgroup operations can use 8-bit integer, 16-bit integer, 64-bit integer, 16-bit floating-point, and vectors of these types in group operations with subgroup scopeif the implementation supports the types.

- `separateDepthStencilLayouts` indicates whether the implementation supports a `VkImageMemoryBarrier` for a depth/stencil image with only one of `VK_IMAGE_ASPECT_DEPTH_BIT` or `VK_IMAGE_ASPECT_STENCIL_BIT` set, and whether `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL`, or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL` can be used.

- `hostQueryReset` indicates that the implementation supports resetting queries from the host with vkResetQueryPool.

- `timelineSemaphore` indicates whether semaphores created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE` are supported.

- `bufferDeviceAddress` indicates that the implementation supports accessing buffer memory in shaders as storage buffers via an address queried from vkGetBufferDeviceAddress.

- `bufferDeviceAddressCaptureReplay` indicates that the implementation supports saving and reusing buffer and device addresses, e.g. for trace capture and replay.

- `bufferDeviceAddressMultiDevice` indicates that the implementation supports the `bufferDeviceAddress` and `rayTracing` features for logical devices created with multiple physical devices. If this feature is not supported, buffer and acceleration structure addresses must not be queried on a logical device created with more than one physical device.

- `vulkanMemoryModel` indicates whether the Vulkan Memory Model is supported, as defined in Vulkan Memory Model. This also indicates whether shader modules can declare the `VulkanMemoryModel` capability.

- `vulkanMemoryModelDeviceScope` indicates whether the Vulkan Memory Model can use `Device` scope synchronization. This also indicates whether shader modules can declare the `VulkanMemoryModelDeviceScope` capability.

- `vulkanMemoryModelAvailabilityVisibilityChains` indicates whether the Vulkan Memory Model can use availability and visibility chains with more than one element.

- `shaderOutputViewportIndex` indicates whether the implementation supports the `ShaderViewportIndex` SPIR-V capability enabling variables decorated with the `ViewportIndex` built-in to be exported from vertex or tessellation evaluation shaders. If this feature is not enabled, the `ViewportIndex` built-in decoration must not be used on outputs in vertex or tessellation evaluation shaders.

- `shaderOutputLayer` indicates whether the implementation supports the `ShaderLayer` SPIR-V capability enabling variables decorated with the `Layer` built-in to be exported from vertex or tessellation evaluation shaders. If this feature is not enabled, the `Layer` built-in decoration must not be used on outputs in vertex or tessellation evaluation shaders.

- If `subgroupBroadcastDynamicId` is `VK_TRUE`, the “Id” operand of `OpGroupNonUniformBroadcast` can be dynamically uniform within a subgroup, and the “Index” operand of `OpGroupNonUniformQuadBroadcast` can be dynamically uniform within the derivative group. If it is `VK_FALSE`, these operands must be constants.

If the `VkPhysicalDeviceVulkan12Features` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether each feature is supported. `VkPhysicalDeviceVulkan12Features` can also be used in the `pNext` chain of VkDeviceCreateInfo to enable the features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VULKAN_1_2_FEATURES`

The `VkPhysicalDeviceVariablePointersFeatures` structure is defined as:

    typedef struct VkPhysicalDeviceVariablePointersFeatures {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           variablePointersStorageBuffer;
        VkBool32           variablePointers;
    } VkPhysicalDeviceVariablePointersFeatures;

or the equivalent

    typedef VkPhysicalDeviceVariablePointersFeatures VkPhysicalDeviceVariablePointersFeaturesKHR;

The members of the `VkPhysicalDeviceVariablePointersFeatures` structure describe the following features:

- `variablePointersStorageBuffer` specifies whether the implementation supports the SPIR-V `VariablePointersStorageBuffer` capability. When this feature is not enabled, shader modules must not declare the `SPV_KHR_variable_pointers` extension or the `VariablePointersStorageBuffer` capability.

- `variablePointers` specifies whether the implementation supports the SPIR-V `VariablePointers` capability. When this feature is not enabled, shader modules must not declare the `VariablePointers` capability.

If the `VkPhysicalDeviceVariablePointersFeatures` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether each feature is supported. `VkPhysicalDeviceVariablePointersFeatures` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable the features.

Valid Usage

- If `variablePointers` is enabled then `variablePointersStorageBuffer` must also be enabled.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VARIABLE_POINTERS_FEATURES`

The `VkPhysicalDeviceMultiviewFeatures` structure is defined as:

    typedef struct VkPhysicalDeviceMultiviewFeatures {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           multiview;
        VkBool32           multiviewGeometryShader;
        VkBool32           multiviewTessellationShader;
    } VkPhysicalDeviceMultiviewFeatures;

or the equivalent

    typedef VkPhysicalDeviceMultiviewFeatures VkPhysicalDeviceMultiviewFeaturesKHR;

The members of the `VkPhysicalDeviceMultiviewFeatures` structure describe the following features:

- `multiview` specifies whether the implementation supports multiview rendering within a render pass. If this feature is not enabled, the view mask of each subpass must always be zero.

- `multiviewGeometryShader` specifies whether the implementation supports multiview rendering within a render pass, with geometry shaders. If this feature is not enabled, then a pipeline compiled against a subpass with a non-zero view mask must not include a geometry shader.

- `multiviewTessellationShader` specifies whether the implementation supports multiview rendering within a render pass, with tessellation shaders. If this feature is not enabled, then a pipeline compiled against a subpass with a non-zero view mask must not include any tessellation shaders.

If the `VkPhysicalDeviceMultiviewFeatures` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether each feature is supported. `VkPhysicalDeviceMultiviewFeatures` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable the features.

Valid Usage

- If `multiviewGeometryShader` is enabled then `multiview` must also be enabled.

- If `multiviewTessellationShader` is enabled then `multiview` must also be enabled.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_FEATURES`

To query 64-bit atomic support for signed and unsigned integers call vkGetPhysicalDeviceFeatures2 with a `VkPhysicalDeviceShaderAtomicInt64Features` structure included in the `pNext` chain of its `pFeatures` parameter.

The VkPhysicalDeviceShaderAtomicInt64Features structure is defined as:

    typedef struct VkPhysicalDeviceShaderAtomicInt64Features {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           shaderBufferInt64Atomics;
        VkBool32           shaderSharedInt64Atomics;
    } VkPhysicalDeviceShaderAtomicInt64Features;

or the equivalent

    typedef VkPhysicalDeviceShaderAtomicInt64Features VkPhysicalDeviceShaderAtomicInt64FeaturesKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `shaderBufferInt64Atomics` indicates whether shaders can support 64-bit unsigned and signed integer atomic operations on buffers.

- `shaderSharedInt64Atomics` indicates whether shaders can support 64-bit unsigned and signed integer atomic operations on shared memory.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_ATOMIC_INT64_FEATURES`

To query 8-bit storage features additionally supported call vkGetPhysicalDeviceFeatures2 with a `VkPhysicalDevice8BitStorageFeatures` structure included in the `pNext` chain of its `pFeatures` parameter. The `VkPhysicalDevice8BitStorageFeatures` structure can also be included in the `pNext` chain of a VkDeviceCreateInfo structure, in which case it controls which additional features are enabled in the device.

The VkPhysicalDevice8BitStorageFeatures structure is defined as:

    typedef struct VkPhysicalDevice8BitStorageFeatures {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           storageBuffer8BitAccess;
        VkBool32           uniformAndStorageBuffer8BitAccess;
        VkBool32           storagePushConstant8;
    } VkPhysicalDevice8BitStorageFeatures;

or the equivalent

    typedef VkPhysicalDevice8BitStorageFeatures VkPhysicalDevice8BitStorageFeaturesKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `storageBuffer8BitAccess` indicates whether objects in the `StorageBuffer` or `PhysicalStorageBuffer` storage class with the `Block` decoration can have 8-bit integer members. If this feature is not enabled, 8-bit integer members must not be used in such objects. This also indicates whether shader modules can declare the `StorageBuffer8BitAccess` capability.

- `uniformAndStorageBuffer8BitAccess` indicates whether objects in the `Uniform` storage class with the `Block` decoration and in the `StorageBuffer` or `PhysicalStorageBuffer` storage class with the same decoration can have 8-bit integer members. If this feature is not enabled, 8-bit integer members must not be used in such objects. This also indicates whether shader modules can declare the `UniformAndStorageBuffer8BitAccess` capability.

- `storagePushConstant8` indicates whether objects in the `PushConstant` storage class can have 8-bit integer members. If this feature is not enabled, 8-bit integer members must not be used in such objects. This also indicates whether shader modules can declare the `StoragePushConstant8` capability.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_8BIT_STORAGE_FEATURES`

To query 16-bit storage features additionally supported call vkGetPhysicalDeviceFeatures2 with a `VkPhysicalDevice16BitStorageFeatures` structure included in the `pNext` chain of its `pFeatures` parameter. The `VkPhysicalDevice16BitStorageFeatures` structure can also be included in the `pNext` chain of a VkDeviceCreateInfo structure, in which case it controls which additional features are enabled in the device.

The VkPhysicalDevice16BitStorageFeatures structure is defined as:

    typedef struct VkPhysicalDevice16BitStorageFeatures {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           storageBuffer16BitAccess;
        VkBool32           uniformAndStorageBuffer16BitAccess;
        VkBool32           storagePushConstant16;
        VkBool32           storageInputOutput16;
    } VkPhysicalDevice16BitStorageFeatures;

or the equivalent

    typedef VkPhysicalDevice16BitStorageFeatures VkPhysicalDevice16BitStorageFeaturesKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `storageBuffer16BitAccess` specifies whether objects in the `StorageBuffer` or `PhysicalStorageBuffer` storage class with the `Block` decoration can have 16-bit integer and 16-bit floating-point members. If this feature is not enabled, 16-bit integer or 16-bit floating-point members must not be used in such objects. This also specifies whether shader modules can declare the `StorageBuffer16BitAccess` capability.

- `uniformAndStorageBuffer16BitAccess` specifies whether objects in the `Uniform` storage class with the `Block` decoration and in the `StorageBuffer` or `PhysicalStorageBuffer` storage class with the same decoration can have 16-bit integer and 16-bit floating-point members. If this feature is not enabled, 16-bit integer or 16-bit floating-point members must not be used in such objects. This also specifies whether shader modules can declare the `UniformAndStorageBuffer16BitAccess` capability.

- `storagePushConstant16` specifies whether objects in the `PushConstant` storage class can have 16-bit integer and 16-bit floating-point members. If this feature is not enabled, 16-bit integer or floating-point members must not be used in such objects. This also specifies whether shader modules can declare the `StoragePushConstant16` capability.

- `storageInputOutput16` specifies whether objects in the `Input` and `Output` storage classes can have 16-bit integer and 16-bit floating-point members. If this feature is not enabled, 16-bit integer or 16-bit floating-point members must not be used in such objects. This also specifies whether shader modules can declare the `StorageInputOutput16` capability.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_16BIT_STORAGE_FEATURES`

To query features additionally supported by the `VK_KHR_shader_float16_int8` extension, call vkGetPhysicalDeviceFeatures2KHR with a `VkPhysicalDeviceShaderFloat16Int8Features` structure included in the `pNext` chain. The `VkPhysicalDeviceShaderFloat16Int8Features` structure can also be included in the `pNext` chain of a VkDeviceCreateInfo structure, in which case it controls which additional features are enabled in the device.

The `VkPhysicalDeviceShaderFloat16Int8Features` structure is defined as:

    typedef struct VkPhysicalDeviceShaderFloat16Int8Features {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           shaderFloat16;
        VkBool32           shaderInt8;
    } VkPhysicalDeviceShaderFloat16Int8Features;

or the equivalent

    typedef VkPhysicalDeviceShaderFloat16Int8Features VkPhysicalDeviceShaderFloat16Int8FeaturesKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `shaderFloat16` indicates whether 16-bit floats (halfs) are supported in shader code. This also indicates whether shader modules can declare the `Float16` capability. However, this only enables a subset of the storage classes that SPIR-V allows for the `Float16` SPIR-V capability: Declaring and using 16-bit floats in the `Private`, `Workgroup`, and `Function` storage classes is enabled, while declaring them in the interface storage classes (e.g., `UniformConstant`, `Uniform`, `StorageBuffer`, `Input`, `Output`, and `PushConstant`) is not enabled.

- `shaderInt8` indicates whether 8-bit integers (signed and unsigned) are supported in shader code. This also indicates whether shader modules can declare the `Int8` capability. However, this only enables a subset of the storage classes that SPIR-V allows for the `Int8` SPIR-V capability: Declaring and using 8-bit integers in the `Private`, `Workgroup`, and `Function` storage classes is enabled, while declaring them in the interface storage classes (e.g., `UniformConstant`, `Uniform`, `StorageBuffer`, `Input`, `Output`, and `PushConstant`) is not enabled.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_FLOAT16_INT8_FEATURES`

To query shader clock support, call vkGetPhysicalDeviceFeatures2 with a `VkPhysicalDeviceShaderClockFeaturesKHR` structure included in the `pNext` chain of its `pFeatures` parameter.

The VkPhysicalDeviceShaderClockFeaturesKHR structure is defined as:

    typedef struct VkPhysicalDeviceShaderClockFeaturesKHR {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           shaderSubgroupClock;
        VkBool32           shaderDeviceClock;
    } VkPhysicalDeviceShaderClockFeaturesKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `shaderSubgroupClock` indicates whether shaders can support `Subgroup` scoped clock reads.

- `shaderDeviceClock` indicates whether shaders can support `Device` scoped clock reads.

If the VkPhysicalDeviceShaderClockFeaturesKHR structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether each feature is supported. VkPhysicalDeviceShaderClockFeaturesKHR can also be included in the `pNext` chain of VkDeviceCreateInfo to enable the features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_CLOCK_FEATURES_KHR`

The `VkPhysicalDeviceSamplerYcbcrConversionFeatures` structure is defined as:

    typedef struct VkPhysicalDeviceSamplerYcbcrConversionFeatures {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           samplerYcbcrConversion;
    } VkPhysicalDeviceSamplerYcbcrConversionFeatures;

or the equivalent

    typedef VkPhysicalDeviceSamplerYcbcrConversionFeatures VkPhysicalDeviceSamplerYcbcrConversionFeaturesKHR;

The members of the `VkPhysicalDeviceSamplerYcbcrConversionFeatures` structure describe the following feature:

- `samplerYcbcrConversion` specifies whether the implementation supports sampler Y′CBCR conversion. If `samplerYcbcrConversion` is `VK_FALSE`, sampler Y′CBCR conversion is not supported, and samplers using sampler Y′CBCR conversion must not be used.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SAMPLER_YCBCR_CONVERSION_FEATURES`

The `VkPhysicalDeviceProtectedMemoryFeatures` structure is defined as:

    typedef struct VkPhysicalDeviceProtectedMemoryFeatures {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           protectedMemory;
    } VkPhysicalDeviceProtectedMemoryFeatures;

- `protectedMemory` specifies whether protected memory is supported.

If the `VkPhysicalDeviceProtectedMemoryFeatures` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with a value indicating whether the feature is supported.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROTECTED_MEMORY_FEATURES`

The `VkPhysicalDeviceBlendOperationAdvancedFeaturesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceBlendOperationAdvancedFeaturesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           advancedBlendCoherentOperations;
    } VkPhysicalDeviceBlendOperationAdvancedFeaturesEXT;

The members of the `VkPhysicalDeviceBlendOperationAdvancedFeaturesEXT` structure describe the following features:

- `advancedBlendCoherentOperations` specifies whether blending using advanced blend operations is guaranteed to execute atomically and in primitive order. If this is `VK_TRUE`, `VK_ACCESS_COLOR_ATTACHMENT_READ_NONCOHERENT_BIT_EXT` is treated the same as `VK_ACCESS_COLOR_ATTACHMENT_READ_BIT`, and advanced blending needs no additional synchronization over basic blending. If this is `VK_FALSE`, then memory dependencies are required to guarantee order between two advanced blending operations that occur on the same sample.

If the `VkPhysicalDeviceBlendOperationAdvancedFeaturesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether each feature is supported. `VkPhysicalDeviceBlendOperationAdvancedFeaturesEXT` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable the features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_BLEND_OPERATION_ADVANCED_FEATURES_EXT`

The `VkPhysicalDeviceConditionalRenderingFeaturesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceConditionalRenderingFeaturesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           conditionalRendering;
        VkBool32           inheritedConditionalRendering;
    } VkPhysicalDeviceConditionalRenderingFeaturesEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `conditionalRendering` specifies whether conditional rendering is supported.

- `inheritedConditionalRendering` specifies whether a secondary command buffer can be executed while conditional rendering is active in the primary command buffer.

If the `VkPhysicalDeviceConditionalRenderingFeaturesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating the implementation-dependent behavior. `VkPhysicalDeviceConditionalRenderingFeaturesEXT` can also be included in `pNext` chain of VkDeviceCreateInfo to enable the features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_CONDITIONAL_RENDERING_FEATURES_EXT`

The `VkPhysicalDeviceShaderDrawParametersFeatures` structure is defined as:

    typedef struct VkPhysicalDeviceShaderDrawParametersFeatures {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           shaderDrawParameters;
    } VkPhysicalDeviceShaderDrawParametersFeatures;

- `shaderDrawParameters` specifies whether shader draw parameters are supported.

If the `VkPhysicalDeviceShaderDrawParametersFeatures` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with a value indicating whether the feature is supported.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_DRAW_PARAMETERS_FEATURES`

The `VkPhysicalDeviceMeshShaderFeaturesNV` structure is defined as:

    typedef struct VkPhysicalDeviceMeshShaderFeaturesNV {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           taskShader;
        VkBool32           meshShader;
    } VkPhysicalDeviceMeshShaderFeaturesNV;

- `taskShader` indicates whether the task shader stage is supported.

- `meshShader` indicates whether the mesh shader stage is supported.

If the `VkPhysicalDeviceMeshShaderFeaturesNV` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with a value indicating whether the feature is supported. `VkPhysicalDeviceMeshShaderFeaturesNV` can also be included in `pNext` chain of VkDeviceCreateInfo to enable the features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MESH_SHADER_FEATURES_NV`

The `VkPhysicalDeviceDescriptorIndexingFeatures` structure is defined as:

    typedef struct VkPhysicalDeviceDescriptorIndexingFeatures {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           shaderInputAttachmentArrayDynamicIndexing;
        VkBool32           shaderUniformTexelBufferArrayDynamicIndexing;
        VkBool32           shaderStorageTexelBufferArrayDynamicIndexing;
        VkBool32           shaderUniformBufferArrayNonUniformIndexing;
        VkBool32           shaderSampledImageArrayNonUniformIndexing;
        VkBool32           shaderStorageBufferArrayNonUniformIndexing;
        VkBool32           shaderStorageImageArrayNonUniformIndexing;
        VkBool32           shaderInputAttachmentArrayNonUniformIndexing;
        VkBool32           shaderUniformTexelBufferArrayNonUniformIndexing;
        VkBool32           shaderStorageTexelBufferArrayNonUniformIndexing;
        VkBool32           descriptorBindingUniformBufferUpdateAfterBind;
        VkBool32           descriptorBindingSampledImageUpdateAfterBind;
        VkBool32           descriptorBindingStorageImageUpdateAfterBind;
        VkBool32           descriptorBindingStorageBufferUpdateAfterBind;
        VkBool32           descriptorBindingUniformTexelBufferUpdateAfterBind;
        VkBool32           descriptorBindingStorageTexelBufferUpdateAfterBind;
        VkBool32           descriptorBindingUpdateUnusedWhilePending;
        VkBool32           descriptorBindingPartiallyBound;
        VkBool32           descriptorBindingVariableDescriptorCount;
        VkBool32           runtimeDescriptorArray;
    } VkPhysicalDeviceDescriptorIndexingFeatures;

or the equivalent

    typedef VkPhysicalDeviceDescriptorIndexingFeatures VkPhysicalDeviceDescriptorIndexingFeaturesEXT;

The members of the `VkPhysicalDeviceDescriptorIndexingFeatures` structure describe the following features:

- `shaderInputAttachmentArrayDynamicIndexing` indicates whether arrays of input attachments can be indexed by dynamically uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT` must be indexed only by constant integral expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare the `InputAttachmentArrayDynamicIndexing` capability.

- `shaderUniformTexelBufferArrayDynamicIndexing` indicates whether arrays of uniform texel buffers can be indexed by dynamically uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER` must be indexed only by constant integral expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare the `UniformTexelBufferArrayDynamicIndexing` capability.

- `shaderStorageTexelBufferArrayDynamicIndexing` indicates whether arrays of storage texel buffers can be indexed by dynamically uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER` must be indexed only by constant integral expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare the `StorageTexelBufferArrayDynamicIndexing` capability.

- `shaderUniformBufferArrayNonUniformIndexing` indicates whether arrays of uniform buffers can be indexed by non-uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER` or `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC` must not be indexed by non-uniform integer expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare the `UniformBufferArrayNonUniformIndexing` capability.

- `shaderSampledImageArrayNonUniformIndexing` indicates whether arrays of samplers or sampled images can be indexed by non-uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_SAMPLER`, `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, or `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE` must not be indexed by non-uniform integer expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare the `SampledImageArrayNonUniformIndexing` capability.

- `shaderStorageBufferArrayNonUniformIndexing` indicates whether arrays of storage buffers can be indexed by non-uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER` or `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC` must not be indexed by non-uniform integer expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare the `StorageBufferArrayNonUniformIndexing` capability.

- `shaderStorageImageArrayNonUniformIndexing` indicates whether arrays of storage images can be indexed by non-uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE` must not be indexed by non-uniform integer expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare the `StorageImageArrayNonUniformIndexing` capability.

- `shaderInputAttachmentArrayNonUniformIndexing` indicates whether arrays of input attachments can be indexed by non-uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT` must not be indexed by non-uniform integer expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare the `InputAttachmentArrayNonUniformIndexing` capability.

- `shaderUniformTexelBufferArrayNonUniformIndexing` indicates whether arrays of uniform texel buffers can be indexed by non-uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER` must not be indexed by non-uniform integer expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare the `UniformTexelBufferArrayNonUniformIndexing` capability.

- `shaderStorageTexelBufferArrayNonUniformIndexing` indicates whether arrays of storage texel buffers can be indexed by non-uniform integer expressions in shader code. If this feature is not enabled, resources with a descriptor type of `VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER` must not be indexed by non-uniform integer expressions when aggregated into arrays in shader code. This also indicates whether shader modules can declare the `StorageTexelBufferArrayNonUniformIndexing` capability.

- `descriptorBindingUniformBufferUpdateAfterBind` indicates whether the implementation supports updating uniform buffer descriptors after a set is bound. If this feature is not enabled, `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT` must not be used with `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER`.

- `descriptorBindingSampledImageUpdateAfterBind` indicates whether the implementation supports updating sampled image descriptors after a set is bound. If this feature is not enabled, `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT` must not be used with `VK_DESCRIPTOR_TYPE_SAMPLER`, `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, or `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE`.

- `descriptorBindingStorageImageUpdateAfterBind` indicates whether the implementation supports updating storage image descriptors after a set is bound. If this feature is not enabled, `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT` must not be used with `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE`.

- `descriptorBindingStorageBufferUpdateAfterBind` indicates whether the implementation supports updating storage buffer descriptors after a set is bound. If this feature is not enabled, `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT` must not be used with `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER`.

- `descriptorBindingUniformTexelBufferUpdateAfterBind` indicates whether the implementation supports updating uniform texel buffer descriptors after a set is bound. If this feature is not enabled, `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT` must not be used with `VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER`.

- `descriptorBindingStorageTexelBufferUpdateAfterBind` indicates whether the implementation supports updating storage texel buffer descriptors after a set is bound. If this feature is not enabled, `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT` must not be used with `VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER`.

- `descriptorBindingUpdateUnusedWhilePending` indicates whether the implementation supports updating descriptors while the set is in use. If this feature is not enabled, `VK_DESCRIPTOR_BINDING_UPDATE_UNUSED_WHILE_PENDING_BIT` must not be used.

- `descriptorBindingPartiallyBound` indicates whether the implementation supports statically using a descriptor set binding in which some descriptors are not valid. If this feature is not enabled, `VK_DESCRIPTOR_BINDING_PARTIALLY_BOUND_BIT` must not be used.

- `descriptorBindingVariableDescriptorCount` indicates whether the implementation supports descriptor sets with a variable-sized last binding. If this feature is not enabled, `VK_DESCRIPTOR_BINDING_VARIABLE_DESCRIPTOR_COUNT_BIT` must not be used.

- `runtimeDescriptorArray` indicates whether the implementation supports the SPIR-V `RuntimeDescriptorArray` capability. If this feature is not enabled, descriptors must not be declared in runtime arrays.

If the `VkPhysicalDeviceDescriptorIndexingFeatures` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether each feature is supported. `VkPhysicalDeviceDescriptorIndexingFeatures` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_FEATURES`

The `VkPhysicalDeviceVertexAttributeDivisorFeaturesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceVertexAttributeDivisorFeaturesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           vertexAttributeInstanceRateDivisor;
        VkBool32           vertexAttributeInstanceRateZeroDivisor;
    } VkPhysicalDeviceVertexAttributeDivisorFeaturesEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `vertexAttributeInstanceRateDivisor` specifies whether vertex attribute fetching may be repeated in case of instanced rendering.

- `vertexAttributeInstanceRateZeroDivisor` specifies whether a zero value for `VkVertexInputBindingDivisorDescriptionEXT`::`divisor` is supported.

If the `VkPhysicalDeviceVertexAttributeDivisorFeaturesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating the implementation-dependent behavior. `VkPhysicalDeviceVertexAttributeDivisorFeaturesEXT` can also be included in `pNext` chain of VkDeviceCreateInfo to enable the feature.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VERTEX_ATTRIBUTE_DIVISOR_FEATURES_EXT`

The `VkPhysicalDeviceASTCDecodeFeaturesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceASTCDecodeFeaturesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           decodeModeSharedExponent;
    } VkPhysicalDeviceASTCDecodeFeaturesEXT;

The members of the `VkPhysicalDeviceASTCDecodeFeaturesEXT` structure describe the following features:

- `decodeModeSharedExponent` indicates whether the implementation supports decoding ASTC compressed formats to `VK_FORMAT_E5B9G9R9_UFLOAT_PACK32` internal precision.

If the `VkPhysicalDeviceASTCDecodeFeaturesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether each feature is supported. `VkPhysicalDeviceASTCDecodeFeaturesEXT` can also be included in the `pNext` chain of vkCreateDevice to enable features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_ASTC_DECODE_FEATURES_EXT`

The `VkPhysicalDeviceTransformFeedbackFeaturesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceTransformFeedbackFeaturesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           transformFeedback;
        VkBool32           geometryStreams;
    } VkPhysicalDeviceTransformFeedbackFeaturesEXT;

The members of the `VkPhysicalDeviceTransformFeedbackFeaturesEXT` structure describe the following features:

- `transformFeedback` indicates whether the implementation supports transform feedback and shader modules can declare the `TransformFeedback` capability.

- `geometryStreams` indicates whether the implementation supports the `GeometryStreams` SPIR-V capability.

If the `VkPhysicalDeviceTransformFeedbackFeaturesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether each feature is supported. `VkPhysicalDeviceTransformFeedbackFeaturesEXT` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TRANSFORM_FEEDBACK_FEATURES_EXT`

To query memory model features additionally supported call vkGetPhysicalDeviceFeatures2 with a `VkPhysicalDeviceVulkanMemoryModelFeatures` structure included in the `pNext` chain of its `pFeatures` parameter. The `VkPhysicalDeviceVulkanMemoryModelFeatures` structure can also be included in the `pNext` chain of a VkDeviceCreateInfo structure, in which case it controls which additional features are enabled in the device.

The VkPhysicalDeviceVulkanMemoryModelFeatures structure is defined as:

    typedef struct VkPhysicalDeviceVulkanMemoryModelFeatures {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           vulkanMemoryModel;
        VkBool32           vulkanMemoryModelDeviceScope;
        VkBool32           vulkanMemoryModelAvailabilityVisibilityChains;
    } VkPhysicalDeviceVulkanMemoryModelFeatures;

or the equivalent

    typedef VkPhysicalDeviceVulkanMemoryModelFeatures VkPhysicalDeviceVulkanMemoryModelFeaturesKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `vulkanMemoryModel` indicates whether the Vulkan Memory Model is supported, as defined in Vulkan Memory Model. This also indicates whether shader modules can declare the `VulkanMemoryModel` capability.

- `vulkanMemoryModelDeviceScope` indicates whether the Vulkan Memory Model can use `Device` scope synchronization. This also indicates whether shader modules can declare the `VulkanMemoryModelDeviceScope` capability.

- `vulkanMemoryModelAvailabilityVisibilityChains` indicates whether the Vulkan Memory Model can use availability and visibility chains with more than one element.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VULKAN_MEMORY_MODEL_FEATURES`

The `VkPhysicalDeviceInlineUniformBlockFeaturesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceInlineUniformBlockFeaturesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           inlineUniformBlock;
        VkBool32           descriptorBindingInlineUniformBlockUpdateAfterBind;
    } VkPhysicalDeviceInlineUniformBlockFeaturesEXT;

The members of the `VkPhysicalDeviceInlineUniformBlockFeaturesEXT` structure describe the following features:

- `inlineUniformBlock` indicates whether the implementation supports inline uniform block descriptors. If this feature is not enabled, `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` must not be used.

- `descriptorBindingInlineUniformBlockUpdateAfterBind` indicates whether the implementation supports updating inline uniform block descriptors after a set is bound. If this feature is not enabled, `VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT` must not be used with `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT`.

If the `VkPhysicalDeviceInlineUniformBlockFeaturesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether each feature is supported. `VkPhysicalDeviceInlineUniformBlockFeaturesEXT` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_INLINE_UNIFORM_BLOCK_FEATURES_EXT`

The `VkPhysicalDeviceRepresentativeFragmentTestFeaturesNV` structure is defined as:

    typedef struct VkPhysicalDeviceRepresentativeFragmentTestFeaturesNV {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           representativeFragmentTest;
    } VkPhysicalDeviceRepresentativeFragmentTestFeaturesNV;

The members of the `VkPhysicalDeviceRepresentativeFragmentTestFeaturesNV` structure describe the following features:

- `representativeFragmentTest` indicates whether the implementation supports the representative fragment test. See Representative Fragment Test.

If the `VkPhysicalDeviceRepresentativeFragmentTestFeaturesNV` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceRepresentativeFragmentTestFeaturesNV` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable the feature.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_REPRESENTATIVE_FRAGMENT_TEST_FEATURES_NV`

The `VkPhysicalDeviceExclusiveScissorFeaturesNV` structure is defined as:

    typedef struct VkPhysicalDeviceExclusiveScissorFeaturesNV {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           exclusiveScissor;
    } VkPhysicalDeviceExclusiveScissorFeaturesNV;

The members of the `VkPhysicalDeviceExclusiveScissorFeaturesNV` structure describe the following features:

- `exclusiveScissor` indicates that the implementation supports the exclusive scissor test.

See Exclusive Scissor Test for more information.

If the `VkPhysicalDeviceExclusiveScissorFeaturesNV` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceExclusiveScissorFeaturesNV` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable the feature.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXCLUSIVE_SCISSOR_FEATURES_NV`

The `VkPhysicalDeviceCornerSampledImageFeaturesNV` structure is defined as:

    typedef struct VkPhysicalDeviceCornerSampledImageFeaturesNV {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           cornerSampledImage;
    } VkPhysicalDeviceCornerSampledImageFeaturesNV;

The members of the `VkPhysicalDeviceCornerSampledImageFeaturesNV` structure describe the following features:

- `cornerSampledImage` specifies whether images can be created with a VkImageCreateInfo::`flags` containing `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV`. See Corner-Sampled Images.

If the `VkPhysicalDeviceCornerSampledImageFeaturesNV` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether each feature is supported. `VkPhysicalDeviceCornerSampledImageFeaturesNV` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_CORNER_SAMPLED_IMAGE_FEATURES_NV`

The `VkPhysicalDeviceComputeShaderDerivativesFeaturesNV` structure is defined as:

    typedef struct VkPhysicalDeviceComputeShaderDerivativesFeaturesNV {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           computeDerivativeGroupQuads;
        VkBool32           computeDerivativeGroupLinear;
    } VkPhysicalDeviceComputeShaderDerivativesFeaturesNV;

The members of the `VkPhysicalDeviceComputeShaderDerivativesFeaturesNV` structure describe the following features:

- `computeDerivativeGroupQuads` indicates that the implementation supports the `ComputeDerivativeGroupQuadsNV` SPIR-V capability.

- `computeDerivativeGroupLinear` indicates that the implementation supports the `ComputeDerivativeGroupLinearNV` SPIR-V capability.

See Compute Shader Derivatives for more information.

If the `VkPhysicalDeviceComputeShaderDerivativesFeaturesNV` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether each feature is supported. `VkPhysicalDeviceComputeShaderDerivativesFeaturesNV` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_COMPUTE_SHADER_DERIVATIVES_FEATURES_NV`

The `VkPhysicalDeviceFragmentShaderBarycentricFeaturesNV` structure is defined as:

    typedef struct VkPhysicalDeviceFragmentShaderBarycentricFeaturesNV {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           fragmentShaderBarycentric;
    } VkPhysicalDeviceFragmentShaderBarycentricFeaturesNV;

The members of the `VkPhysicalDeviceFragmentShaderBarycentricFeaturesNV` structure describe the following features:

- `fragmentShaderBarycentric` indicates that the implementation supports the `BaryCoordNV` and `BaryCoordNoPerspNV` SPIR-V fragment shader built-ins and supports the `PerVertexNV` SPIR-V decoration on fragment shader input variables.

See Barycentric Interpolation for more information.

If the `VkPhysicalDeviceFragmentShaderBarycentricFeaturesNV` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceFragmentShaderBarycentricFeaturesNV` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FRAGMENT_SHADER_BARYCENTRIC_FEATURES_NV`

The `VkPhysicalDeviceShaderImageFootprintFeaturesNV` structure is defined as:

    typedef struct VkPhysicalDeviceShaderImageFootprintFeaturesNV {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           imageFootprint;
    } VkPhysicalDeviceShaderImageFootprintFeaturesNV;

- `imageFootprint` specifies whether the implementation supports the `ImageFootprintNV` SPIR-V capability.

See Texel Footprint Evaluation for more information.

If the `VkPhysicalDeviceShaderImageFootprintFeaturesNV` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether each feature is supported. `VkPhysicalDeviceShaderImageFootprintFeaturesNV` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_IMAGE_FOOTPRINT_FEATURES_NV`

The `VkPhysicalDeviceShadingRateImageFeaturesNV` structure is defined as:

    typedef struct VkPhysicalDeviceShadingRateImageFeaturesNV {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           shadingRateImage;
        VkBool32           shadingRateCoarseSampleOrder;
    } VkPhysicalDeviceShadingRateImageFeaturesNV;

The members of the `VkPhysicalDeviceShadingRateImageFeaturesNV` structure describe the following features:

- `shadingRateImage` indicates that the implementation supports the use of a shading rate image to derive an effective shading rate for fragment processing. It also indicates that the implementation supports the `ShadingRateNV` SPIR-V execution mode.

- `shadingRateCoarseSampleOrder` indicates that the implementation supports a user-configurable ordering of coverage samples in fragments larger than one pixel.

See Shading Rate Image for more information.

If the `VkPhysicalDeviceShadingRateImageFeaturesNV` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceShadingRateImageFeaturesNV` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADING_RATE_IMAGE_FEATURES_NV`

The `VkPhysicalDeviceFragmentDensityMapFeaturesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceFragmentDensityMapFeaturesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           fragmentDensityMap;
        VkBool32           fragmentDensityMapDynamic;
        VkBool32           fragmentDensityMapNonSubsampledImages;
    } VkPhysicalDeviceFragmentDensityMapFeaturesEXT;

The members of the `VkPhysicalDeviceFragmentDensityMapFeaturesEXT` structure describe the following features:

- `fragmentDensityMap` specifies whether the implementation supports render passes with a fragment density map attachment. If this feature is not enabled and the `pNext` chain of `VkRenderPassCreateInfo` includes a `VkRenderPassFragmentDensityMapCreateInfoEXT` structure, `fragmentDensityMapAttachment` must be `VK_ATTACHMENT_UNUSED`.

- `fragmentDensityMapDynamic` specifies whether the implementation supports dynamic fragment density map image views. If this feature is not enabled, `VK_IMAGE_VIEW_CREATE_FRAGMENT_DENSITY_MAP_DYNAMIC_BIT_EXT` must not be included in `VkImageViewCreateInfo`::`flags`.

- `fragmentDensityMapNonSubsampledImages` specifies whether the implementation supports regular non-subsampled image attachments with fragment density map render passes. If this feature is not enabled, render passes with a fragment density map attachment must only have subsampled attachments bound.

If the `VkPhysicalDeviceFragmentDensityMapFeaturesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether each feature is supported. `VkPhysicalDeviceFragmentDensityMapFeaturesEXT` can also be included in `pNext` chain of VkDeviceCreateInfo to enable the features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FRAGMENT_DENSITY_MAP_FEATURES_EXT`

The `VkPhysicalDeviceScalarBlockLayoutFeatures` structure is defined as:

    typedef struct VkPhysicalDeviceScalarBlockLayoutFeatures {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           scalarBlockLayout;
    } VkPhysicalDeviceScalarBlockLayoutFeatures;

or the equivalent

    typedef VkPhysicalDeviceScalarBlockLayoutFeatures VkPhysicalDeviceScalarBlockLayoutFeaturesEXT;

The members of the `VkPhysicalDeviceScalarBlockLayoutFeatures` structure describe the following features:

- `scalarBlockLayout` indicates that the implementation supports the layout of resource blocks in shaders using scalar alignment.

If the `VkPhysicalDeviceScalarBlockLayoutFeatures` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceScalarBlockLayoutFeatures` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable this feature.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SCALAR_BLOCK_LAYOUT_FEATURES`

The `VkPhysicalDeviceUniformBufferStandardLayoutFeatures` structure is defined as:

    typedef struct VkPhysicalDeviceUniformBufferStandardLayoutFeatures {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           uniformBufferStandardLayout;
    } VkPhysicalDeviceUniformBufferStandardLayoutFeatures;

or the equivalent

    typedef VkPhysicalDeviceUniformBufferStandardLayoutFeatures VkPhysicalDeviceUniformBufferStandardLayoutFeaturesKHR;

The members of the `VkPhysicalDeviceUniformBufferStandardLayoutFeatures` structure describe the following features:

- `uniformBufferStandardLayout` indicates that the implementation supports the same layouts for uniform buffers as for storage and other kinds of buffers. See Standard Buffer Layout.

If the `VkPhysicalDeviceUniformBufferStandardLayoutFeatures` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceUniformBufferStandardLayoutFeatures` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable this feature.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_UNIFORM_BUFFER_STANDARD_LAYOUT_FEATURES`

The `VkPhysicalDeviceDepthClipEnableFeaturesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceDepthClipEnableFeaturesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           depthClipEnable;
    } VkPhysicalDeviceDepthClipEnableFeaturesEXT;

The members of the `VkPhysicalDeviceDepthClipEnableFeaturesEXT` structure describe the following features:

- `depthClipEnable` indicates that the implementation supports setting the depth clipping operation explicitly via the VkPipelineRasterizationDepthClipStateCreateInfoEXT pipeline state. Otherwise depth clipping is only enabled when `VkPipelineRasterizationStateCreateInfo`::`depthClampEnable` is set to `VK_FALSE`.

If the `VkPhysicalDeviceDepthClipEnableFeaturesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceDepthClipEnableFeaturesEXT` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable this feature.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DEPTH_CLIP_ENABLE_FEATURES_EXT`

The `VkPhysicalDeviceMemoryPriorityFeaturesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceMemoryPriorityFeaturesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           memoryPriority;
    } VkPhysicalDeviceMemoryPriorityFeaturesEXT;

The members of the `VkPhysicalDeviceMemoryPriorityFeaturesEXT` structure describe the following features:

- `memoryPriority` indicates that the implementation supports memory priorities specified at memory allocation time via VkMemoryPriorityAllocateInfoEXT.

If the `VkPhysicalDeviceMemoryPriorityFeaturesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceMemoryPriorityFeaturesEXT` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_PRIORITY_FEATURES_EXT`

The `VkPhysicalDeviceBufferDeviceAddressFeatures` structure is defined as:

    typedef struct VkPhysicalDeviceBufferDeviceAddressFeatures {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           bufferDeviceAddress;
        VkBool32           bufferDeviceAddressCaptureReplay;
        VkBool32           bufferDeviceAddressMultiDevice;
    } VkPhysicalDeviceBufferDeviceAddressFeatures;

or the equivalent

    typedef VkPhysicalDeviceBufferDeviceAddressFeatures VkPhysicalDeviceBufferDeviceAddressFeaturesKHR;

The members of the `VkPhysicalDeviceBufferDeviceAddressFeatures` structure describe the following features:

- `bufferDeviceAddress` indicates that the implementation supports accessing buffer memory in shaders as storage buffers via an address queried from vkGetBufferDeviceAddress.

- `bufferDeviceAddressCaptureReplay` indicates that the implementation supports saving and reusing buffer and device addresses, e.g. for trace capture and replay.

- `bufferDeviceAddressMultiDevice` indicates that the implementation supports the `bufferDeviceAddress` and `rayTracing` features for logical devices created with multiple physical devices. If this feature is not supported, buffer and acceleration structure addresses must not be queried on a logical device created with more than one physical device.

| Note `bufferDeviceAddressMultiDevice` exists to allow certain legacy platforms to be able to support `bufferDeviceAddress` without needing to support shared GPU virtual addresses for multi-device configurations.

See vkGetBufferDeviceAddress for more information.

If the `VkPhysicalDeviceBufferDeviceAddressFeatures` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceBufferDeviceAddressFeatures` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_BUFFER_DEVICE_ADDRESS_FEATURES`

The `VkPhysicalDeviceBufferDeviceAddressFeaturesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceBufferDeviceAddressFeaturesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           bufferDeviceAddress;
        VkBool32           bufferDeviceAddressCaptureReplay;
        VkBool32           bufferDeviceAddressMultiDevice;
    } VkPhysicalDeviceBufferDeviceAddressFeaturesEXT;

The members of the `VkPhysicalDeviceBufferDeviceAddressFeaturesEXT` structure describe the following features:

- `bufferDeviceAddress` indicates that the implementation supports accessing buffer memory in shaders as storage buffers via an address queried from vkGetBufferDeviceAddressEXT.

- `bufferDeviceAddressCaptureReplay` indicates that the implementation supports saving and reusing buffer addresses, e.g. for trace capture and replay.

- `bufferDeviceAddressMultiDevice` indicates that the implementation supports the `bufferDeviceAddress` feature for logical devices created with multiple physical devices. If this feature is not supported, buffer addresses must not be queried on a logical device created with more than one physical device.

If the `VkPhysicalDeviceBufferDeviceAddressFeaturesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceBufferDeviceAddressFeaturesEXT` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable features.

| Note The `VkPhysicalDeviceBufferDeviceAddressFeaturesEXT` structure has the same members as the `VkPhysicalDeviceBufferDeviceAddressFeatures` structure, but the functionality indicated by the members is expressed differently. The features indicated by the `VkPhysicalDeviceBufferDeviceAddressFeatures` structure requires additional flags to be passed at memory allocation time, and the capture and replay mechanism is built around opaque capture addresses for buffer and memory objects.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_BUFFER_DEVICE_ADDRESS_FEATURES_EXT`

The `VkPhysicalDeviceDedicatedAllocationImageAliasingFeaturesNV` structure is defined as:

    typedef struct VkPhysicalDeviceDedicatedAllocationImageAliasingFeaturesNV {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           dedicatedAllocationImageAliasing;
    } VkPhysicalDeviceDedicatedAllocationImageAliasingFeaturesNV;

The members of the `VkPhysicalDeviceDedicatedAllocationImageAliasingFeaturesNV` structure describe the following features:

- `dedicatedAllocationImageAliasing` indicates that the implementation supports aliasing of compatible image objects on a dedicated allocation.

If the `VkPhysicalDeviceDedicatedAllocationImageAliasingFeaturesNV` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether each feature is supported. `VkPhysicalDeviceDedicatedAllocationImageAliasingFeaturesNV` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DEDICATED_ALLOCATION_IMAGE_ALIASING_FEATURES_NV`

The `VkPhysicalDeviceImagelessFramebufferFeatures` structure is defined as:

    typedef struct VkPhysicalDeviceImagelessFramebufferFeatures {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           imagelessFramebuffer;
    } VkPhysicalDeviceImagelessFramebufferFeatures;

or the equivalent

    typedef VkPhysicalDeviceImagelessFramebufferFeatures VkPhysicalDeviceImagelessFramebufferFeaturesKHR;

The members of the `VkPhysicalDeviceImagelessFramebufferFeatures` structure describe the following features:

- `imagelessFramebuffer` indicates that the implementation supports specifying the image view for attachments at render pass begin time via VkRenderPassAttachmentBeginInfo.

If the `VkPhysicalDeviceImagelessFramebufferFeatures` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceImagelessFramebufferFeatures` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable this feature.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGELESS_FRAMEBUFFER_FEATURES`

The `VkPhysicalDeviceFragmentShaderInterlockFeaturesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceFragmentShaderInterlockFeaturesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           fragmentShaderSampleInterlock;
        VkBool32           fragmentShaderPixelInterlock;
        VkBool32           fragmentShaderShadingRateInterlock;
    } VkPhysicalDeviceFragmentShaderInterlockFeaturesEXT;

The members of the `VkPhysicalDeviceFragmentShaderInterlockFeaturesEXT` structure describe the following features:

- `fragmentShaderSampleInterlock` indicates that the implementation supports the `FragmentShaderSampleInterlockEXT` SPIR-V capability.

- `fragmentShaderPixelInterlock` indicates that the implementation supports the `FragmentShaderPixelInterlockEXT` SPIR-V capability.

- `fragmentShaderShadingRateInterlock` indicates that the implementation supports the `FragmentShaderShadingRateInterlockEXT` SPIR-V capability.

If the `VkPhysicalDeviceFragmentShaderInterlockFeaturesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceFragmentShaderInterlockFeaturesEXT` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FRAGMENT_SHADER_INTERLOCK_FEATURES_EXT`

The `VkPhysicalDeviceCooperativeMatrixFeaturesNV` structure is defined as:

    typedef struct VkPhysicalDeviceCooperativeMatrixFeaturesNV {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           cooperativeMatrix;
        VkBool32           cooperativeMatrixRobustBufferAccess;
    } VkPhysicalDeviceCooperativeMatrixFeaturesNV;

The members of the `VkPhysicalDeviceCooperativeMatrixFeaturesNV` structure describe the following features:

- `cooperativeMatrix` indicates that the implementation supports the `CooperativeMatrixNV` SPIR-V capability.

- `cooperativeMatrixRobustBufferAccess` indicates that the implementation supports robust buffer access for SPIR-V `OpCooperativeMatrixLoadNV` and `OpCooperativeMatrixStoreNV` instructions.

If the `VkPhysicalDeviceCooperativeMatrixFeaturesNV` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceCooperativeMatrixFeaturesNV` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_COOPERATIVE_MATRIX_FEATURES_NV`

The `VkPhysicalDeviceYcbcrImageArraysFeaturesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceYcbcrImageArraysFeaturesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           ycbcrImageArrays;
    } VkPhysicalDeviceYcbcrImageArraysFeaturesEXT;

The members of the `VkPhysicalDeviceYcbcrImageArraysFeaturesEXT` structure describe the following features:

- `ycbcrImageArrays` indicates that the implementation supports creating images with a format that requires Y′CBCR conversion and has multiple array layers.

If the `VkPhysicalDeviceYcbcrImageArraysFeaturesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceYcbcrImageArraysFeaturesEXT` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_YCBCR_IMAGE_ARRAYS_FEATURES_EXT`

The `VkPhysicalDeviceShaderSubgroupExtendedTypesFeatures` structure is defined as:

    typedef struct VkPhysicalDeviceShaderSubgroupExtendedTypesFeatures {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           shaderSubgroupExtendedTypes;
    } VkPhysicalDeviceShaderSubgroupExtendedTypesFeatures;

or the equivalent

    typedef VkPhysicalDeviceShaderSubgroupExtendedTypesFeatures VkPhysicalDeviceShaderSubgroupExtendedTypesFeaturesKHR;

The members of the `VkPhysicalDeviceShaderSubgroupExtendedTypesFeatures` structure describe the following features:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `shaderSubgroupExtendedTypes` is a boolean that specifies whether subgroup operations can use 8-bit integer, 16-bit integer, 64-bit integer, 16-bit floating-point, and vectors of these types in group operations with subgroup scopeif the implementation supports the types.

If the `VkPhysicalDeviceShaderSubgroupExtendedTypesFeatures` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether each feature is supported. `VkPhysicalDeviceShaderSubgroupExtendedTypesFeatures` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_SUBGROUP_EXTENDED_TYPES_FEATURES`

The `VkPhysicalDeviceHostQueryResetFeatures` structure is defined as:

    typedef struct VkPhysicalDeviceHostQueryResetFeatures {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           hostQueryReset;
    } VkPhysicalDeviceHostQueryResetFeatures;

or the equivalent

    typedef VkPhysicalDeviceHostQueryResetFeatures VkPhysicalDeviceHostQueryResetFeaturesEXT;

The members of the `VkPhysicalDeviceHostQueryResetFeatures` structure describe the following features:

- `hostQueryReset` indicates that the implementation supports resetting queries from the host with vkResetQueryPool.

If the `VkPhysicalDeviceHostQueryResetFeatures` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceHostQueryResetFeatures` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_HOST_QUERY_RESET_FEATURES`

The `VkPhysicalDeviceShaderIntegerFunctions2FeaturesINTEL` structure is defined as:

    typedef struct VkPhysicalDeviceShaderIntegerFunctions2FeaturesINTEL {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           shaderIntegerFunctions2;
    } VkPhysicalDeviceShaderIntegerFunctions2FeaturesINTEL;

The members of the `VkPhysicalDeviceShaderIntegerFunctions2FeaturesINTEL` structure describe the following features:

- `shaderIntegerFunctions2` indicates that the implementation supports the `ShaderIntegerFunctions2INTEL` SPIR-V capability.

If the `VkPhysicalDeviceShaderIntegerFunctions2FeaturesINTEL` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceShaderIntegerFunctions2FeaturesINTEL` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_INTEGER_FUNCTIONS_2_FEATURES_INTEL`

The `VkPhysicalDeviceCoverageReductionModeFeaturesNV` structure is defined as:

    typedef struct VkPhysicalDeviceCoverageReductionModeFeaturesNV {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           coverageReductionMode;
    } VkPhysicalDeviceCoverageReductionModeFeaturesNV;

The members of the `VkPhysicalDeviceCoverageReductionModeFeaturesNV` structure describe the following features:

- `coverageReductionMode` indicates whether the implementation supports coverage reduction modes. See Coverage Reduction.

If the `VkPhysicalDeviceCoverageReductionModeFeaturesNV` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceCoverageReductionModeFeaturesNV` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable the feature.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_COVERAGE_REDUCTION_MODE_FEATURES_NV`

The `VkPhysicalDeviceTimelineSemaphoreFeatures` structure is defined as:

    typedef struct VkPhysicalDeviceTimelineSemaphoreFeatures {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           timelineSemaphore;
    } VkPhysicalDeviceTimelineSemaphoreFeatures;

or the equivalent

    typedef VkPhysicalDeviceTimelineSemaphoreFeatures VkPhysicalDeviceTimelineSemaphoreFeaturesKHR;

The members of the `VkPhysicalDeviceTimelineSemaphoreFeatures` structure describe the following features:

- `timelineSemaphore` indicates whether semaphores created with a VkSemaphoreType of `VK_SEMAPHORE_TYPE_TIMELINE` are supported.

If the `VkPhysicalDeviceTimelineSemaphoreFeatures` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether each feature is supported. `VkPhysicalDeviceTimelineSemaphoreFeatures` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TIMELINE_SEMAPHORE_FEATURES`

The `VkPhysicalDeviceIndexTypeUint8FeaturesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceIndexTypeUint8FeaturesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           indexTypeUint8;
    } VkPhysicalDeviceIndexTypeUint8FeaturesEXT;

The members of the `VkPhysicalDeviceIndexTypeUint8FeaturesEXT` structure describe the following features:

- `indexTypeUint8` indicates that `VK_INDEX_TYPE_UINT8_EXT` can be used with vkCmdBindIndexBuffer.

If the `VkPhysicalDeviceIndexTypeUint8FeaturesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceIndexTypeUint8FeaturesEXT` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_INDEX_TYPE_UINT8_FEATURES_EXT`

The `VkPhysicalDeviceShaderSMBuiltinsFeaturesNV` structure is defined as:

    typedef struct VkPhysicalDeviceShaderSMBuiltinsFeaturesNV {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           shaderSMBuiltins;
    } VkPhysicalDeviceShaderSMBuiltinsFeaturesNV;

The members of the `VkPhysicalDeviceShaderSMBuiltinsFeaturesNV` structure describe the following features:

- `shaderSMBuiltins` indicates whether the implementation supports the SPIR-V `ShaderSMBuiltinsNV` capability.

If the `VkPhysicalDeviceShaderSMBuiltinsFeaturesNV` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceShaderSMBuiltinsFeaturesNV` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable the feature.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_SM_BUILTINS_FEATURES_NV`

The `VkPhysicalDeviceSeparateDepthStencilLayoutsFeatures` structure is defined as:

    typedef struct VkPhysicalDeviceSeparateDepthStencilLayoutsFeatures {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           separateDepthStencilLayouts;
    } VkPhysicalDeviceSeparateDepthStencilLayoutsFeatures;

or the equivalent

    typedef VkPhysicalDeviceSeparateDepthStencilLayoutsFeatures VkPhysicalDeviceSeparateDepthStencilLayoutsFeaturesKHR;

The members of the `VkPhysicalDeviceSeparateDepthStencilLayoutsFeatures` structure describe the following features:

- `separateDepthStencilLayouts` indicates whether the implementation supports a `VkImageMemoryBarrier` for a depth/stencil image with only one of `VK_IMAGE_ASPECT_DEPTH_BIT` or `VK_IMAGE_ASPECT_STENCIL_BIT` set, and whether `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL`, `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL`, `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL`, or `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL` can be used.

If the `VkPhysicalDeviceSeparateDepthStencilLayoutsFeatures` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceSeparateDepthStencilLayoutsFeatures` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable the feature.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SEPARATE_DEPTH_STENCIL_LAYOUTS_FEATURES`

The `VkPhysicalDevicePipelineExecutablePropertiesFeaturesKHR` structure is defined as:

    typedef struct VkPhysicalDevicePipelineExecutablePropertiesFeaturesKHR {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           pipelineExecutableInfo;
    } VkPhysicalDevicePipelineExecutablePropertiesFeaturesKHR;

The members of the `VkPhysicalDevicePipelineExecutablePropertiesFeaturesKHR` structure describe the following features:

- `pipelineExecutableInfo` indicates that the implementation supports reporting properties and statistics about the executables associated with a compiled pipeline.

If the `VkPhysicalDevicePipelineExecutablePropertiesFeaturesKHR` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDevicePipelineExecutablePropertiesFeaturesKHR` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PIPELINE_EXECUTABLE_PROPERTIES_FEATURES_KHR`

The `VkPhysicalDeviceShaderDemoteToHelperInvocationFeaturesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceShaderDemoteToHelperInvocationFeaturesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           shaderDemoteToHelperInvocation;
    } VkPhysicalDeviceShaderDemoteToHelperInvocationFeaturesEXT;

The members of the `VkPhysicalDeviceShaderDemoteToHelperInvocationFeaturesEXT` structure describe the following features:

- `shaderDemoteToHelperInvocation` indicates whether the implementation supports the SPIR-V `DemoteToHelperInvocationEXT` capability.

If the `VkPhysicalDeviceShaderDemoteToHelperInvocationFeaturesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceShaderDemoteToHelperInvocationFeaturesEXT` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable the feature.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_DEMOTE_TO_HELPER_INVOCATION_FEATURES_EXT`

The `VkPhysicalDeviceTexelBufferAlignmentFeaturesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceTexelBufferAlignmentFeaturesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           texelBufferAlignment;
    } VkPhysicalDeviceTexelBufferAlignmentFeaturesEXT;

The members of the `VkPhysicalDeviceTexelBufferAlignmentFeaturesEXT` structure describe the following features:

- `texelBufferAlignment` indicates whether the implementation uses more specific alignment requirements advertised in VkPhysicalDeviceTexelBufferAlignmentPropertiesEXT rather than VkPhysicalDeviceLimits::`minTexelBufferOffsetAlignment`.

If the `VkPhysicalDeviceTexelBufferAlignmentFeaturesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceTexelBufferAlignmentFeaturesEXT` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable the feature.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TEXEL_BUFFER_ALIGNMENT_FEATURES_EXT`

The `VkPhysicalDeviceTextureCompressionASTCHDRFeaturesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceTextureCompressionASTCHDRFeaturesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           textureCompressionASTC_HDR;
    } VkPhysicalDeviceTextureCompressionASTCHDRFeaturesEXT;

The members of the `VkPhysicalDeviceTextureCompressionASTCHDRFeaturesEXT` structure describe the following features:

- `textureCompressionASTC_HDR` indicates whether all of the ASTC HDR compressed texture formats are supported. If this feature is enabled, then the `VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT`, `VK_FORMAT_FEATURE_BLIT_SRC_BIT` and `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT` features must be supported in `optimalTilingFeatures` for the following formats:

  - `VK_FORMAT_ASTC_4x4_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_5x4_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_5x5_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_6x5_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_6x6_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_8x5_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_8x6_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_8x8_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_10x5_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_10x6_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_10x8_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_10x10_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_12x10_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_12x12_SFLOAT_BLOCK_EXT`

  To query for additional properties, or if the feature is not enabled, vkGetPhysicalDeviceFormatProperties and vkGetPhysicalDeviceImageFormatProperties can be used to check for supported properties of individual formats as normal.

If the `VkPhysicalDeviceTextureCompressionASTCHDRFeaturesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether each feature is supported. `VkPhysicalDeviceTextureCompressionASTCHDRFeaturesEXT` can also be included in the `pNext` chain of vkCreateDevice to enable features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TEXTURE_COMPRESSION_ASTC_HDR_FEATURES_EXT`

The `VkPhysicalDeviceLineRasterizationFeaturesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceLineRasterizationFeaturesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           rectangularLines;
        VkBool32           bresenhamLines;
        VkBool32           smoothLines;
        VkBool32           stippledRectangularLines;
        VkBool32           stippledBresenhamLines;
        VkBool32           stippledSmoothLines;
    } VkPhysicalDeviceLineRasterizationFeaturesEXT;

The members of the `VkPhysicalDeviceLineRasterizationFeaturesEXT` structure describe the following features:

- `rectangularLines` indicates whether the implementation supports rectangular line rasterization.

- `bresenhamLines` indicates whether the implementation supports Bresenham-style line rasterization.

- `smoothLines` indicates whether the implementation supports smooth line rasterization.

- `stippledRectangularLines` indicates whether the implementation supports stippled line rasterization with `VK_LINE_RASTERIZATION_MODE_RECTANGULAR_EXT` lines, or with `VK_LINE_RASTERIZATION_MODE_DEFAULT_EXT` lines if VkPhysicalDeviceLimits::`strictLines` is `VK_TRUE`.

- `stippledBresenhamLines` indicates whether the implementation supports stippled line rasterization with `VK_LINE_RASTERIZATION_MODE_BRESENHAM_EXT` lines.

- `stippledSmoothLines` indicates whether the implementation supports stippled line rasterization with `VK_LINE_RASTERIZATION_MODE_RECTANGULAR_SMOOTH_EXT` lines.

If the `VkPhysicalDeviceLineRasterizationFeaturesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceLineRasterizationFeaturesEXT` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable the feature.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_LINE_RASTERIZATION_FEATURES_EXT`

The `VkPhysicalDeviceSubgroupSizeControlFeaturesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceSubgroupSizeControlFeaturesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           subgroupSizeControl;
        VkBool32           computeFullSubgroups;
    } VkPhysicalDeviceSubgroupSizeControlFeaturesEXT;

The members of the `VkPhysicalDeviceSubgroupSizeControlFeaturesEXT` structure describe the following features:

- `subgroupSizeControl` indicates whether the implementation supports controlling shader subgroup sizes via the `VK_PIPELINE_SHADER_STAGE_CREATE_ALLOW_VARYING_SUBGROUP_SIZE_BIT_EXT` flag and the VkPipelineShaderStageRequiredSubgroupSizeCreateInfoEXT structure.

- `computeFullSubgroups` indicates whether the implementation supports requiring full subgroups in compute shaders via the `VK_PIPELINE_SHADER_STAGE_CREATE_REQUIRE_FULL_SUBGROUPS_BIT_EXT` flag.

If the `VkPhysicalDeviceSubgroupSizeControlFeaturesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceSubgroupSizeControlFeaturesEXT` can also be included in the `pNext` chain of VkDeviceCreateInfo to enable the feature.

| Note The `VkPhysicalDeviceSubgroupSizeControlFeaturesEXT` structure was added in version 2 of the `VK_EXT_subgroup_size_control` extension. Version 1 implementations of this extension will not fill out the features structure but applications may assume that both `subgroupSizeControl` and `computeFullSubgroups` are supported if the extension is supported. (See also the Feature Requirements section.) Applications are advised to add a `VkPhysicalDeviceSubgroupSizeControlFeaturesEXT` structure to the `pNext` chain of VkDeviceCreateInfo to enable the features regardless of the version of the extension supported by the implementation. If the implementation only supports version 1, it will safely ignore the `VkPhysicalDeviceSubgroupSizeControlFeaturesEXT` structure.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SUBGROUP_SIZE_CONTROL_FEATURES_EXT`

The `VkPhysicalDeviceCoherentMemoryFeaturesAMD` structure is defined as:

    typedef struct VkPhysicalDeviceCoherentMemoryFeaturesAMD {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           deviceCoherentMemory;
    } VkPhysicalDeviceCoherentMemoryFeaturesAMD;

The members of the `VkPhysicalDeviceCoherentMemoryFeaturesAMD` structure describe the following features:

- `deviceCoherentMemory` indicates that the implementation supports device coherent memory.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_COHERENT_MEMORY_FEATURES_AMD`

The `VkPhysicalDeviceRayTracingFeaturesKHR` structure is defined as:

    typedef struct VkPhysicalDeviceRayTracingFeaturesKHR {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           rayTracing;
        VkBool32           rayTracingShaderGroupHandleCaptureReplay;
        VkBool32           rayTracingShaderGroupHandleCaptureReplayMixed;
        VkBool32           rayTracingAccelerationStructureCaptureReplay;
        VkBool32           rayTracingIndirectTraceRays;
        VkBool32           rayTracingIndirectAccelerationStructureBuild;
        VkBool32           rayTracingHostAccelerationStructureCommands;
        VkBool32           rayQuery;
        VkBool32           rayTracingPrimitiveCulling;
    } VkPhysicalDeviceRayTracingFeaturesKHR;

The members of the `VkPhysicalDeviceRayTracingFeaturesKHR` structure describe the following features:

- `rayTracing` indicates whether the implementation supports ray tracing functionality. See Ray Tracing.

- `rayTracingShaderGroupHandleCaptureReplay` indicates whether the implementation supports saving and reusing shader group handles, e.g. for trace capture and replay.

- `rayTracingShaderGroupHandleCaptureReplayMixed` indicates whether the implementation supports reuse of shader group handles being arbitrarily mixed with creation of non-reused shader group handles. If this is `VK_FALSE`, all reused shader group handles must be specified before any non-reused handles may be created.

- `rayTracingAccelerationStructureCaptureReplay` indicates whether the implementation supports saving and reusing acceleration structure device addresses, e.g. for trace capture and replay.

- `rayTracingIndirectTraceRays` indicates whether the implementation supports indirect trace ray commands, e.g. vkCmdTraceRaysIndirectKHR.

- `rayTracingIndirectAccelerationStructureBuild` indicates whether the implementation supports indirect acceleration structure build commands, e.g. vkCmdBuildAccelerationStructureIndirectKHR.

- `rayTracingHostAccelerationStructureCommands` indicates whether the implementation supports host side acceleration structure commands, e.g. vkBuildAccelerationStructureKHR, vkCopyAccelerationStructureKHR, vkCopyAccelerationStructureToMemoryKHR, vkCopyMemoryToAccelerationStructureKHR, vkWriteAccelerationStructuresPropertiesKHR.

- `rayQuery` indicates whether the implementation supports ray query (`OpRayQueryProceedKHR`) functionality.

- `rayTracingPrimitiveCulling` indicates whether the implementation supports primitive culling during ray traversal.

If the `VkPhysicalDeviceRayTracingFeaturesKHR` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceRayTracingFeaturesKHR` can also be used in the `pNext` chain of VkDeviceCreateInfo to enable the features.

Valid Usage

- If `rayTracingShaderGroupHandleCaptureReplayMixed` is `VK_TRUE`, `rayTracingShaderGroupHandleCaptureReplay` must also be `VK_TRUE`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_RAY_TRACING_FEATURES_KHR`

The `VkPhysicalDeviceDeviceGeneratedCommandsFeaturesNV` structure is defined as:

    typedef struct VkPhysicalDeviceDeviceGeneratedCommandsFeaturesNV {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           deviceGeneratedCommands;
    } VkPhysicalDeviceDeviceGeneratedCommandsFeaturesNV;

The members of the `VkPhysicalDeviceDeviceGeneratedCommandsFeaturesNV` structure describe the following features:

- `deviceGeneratedCommands` indicates whether the implementation supports functionality to generate commands on the device. See Device-Generated Commands.

If the `VkPhysicalDeviceDeviceGeneratedCommandsFeaturesNV` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceDeviceGeneratedCommandsFeaturesNV` can also be used in the `pNext` chain of VkDeviceCreateInfo to enable the features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DEVICE_GENERATED_COMMANDS_FEATURES_NV`

The `VkPhysicalDeviceDiagnosticsConfigFeaturesNV` structure is defined as:

    typedef struct VkPhysicalDeviceDiagnosticsConfigFeaturesNV {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           diagnosticsConfig;
    } VkPhysicalDeviceDiagnosticsConfigFeaturesNV;

The members of the `VkPhysicalDeviceDiagnosticsConfigFeaturesNV` structure describe the following features:

- `diagnosticsConfig` indicates whether the implementation supports the ability to configure diagnostic tools.

If the `VkPhysicalDeviceDiagnosticsConfigFeaturesNV` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDeviceDiagnosticsConfigFeaturesNV` can also be used in the `pNext` chain of VkDeviceCreateInfo to enable the feature.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DIAGNOSTICS_CONFIG_FEATURES_NV`

The `VkPhysicalDevicePipelineCreationCacheControlFeaturesEXT` structure is defined as:

    typedef struct VkPhysicalDevicePipelineCreationCacheControlFeaturesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           pipelineCreationCacheControl;
    } VkPhysicalDevicePipelineCreationCacheControlFeaturesEXT;

The members of the `VkPhysicalDevicePipelineCreationCacheControlFeaturesEXT` structure describe the following features:

- `pipelineCreationCacheControl` indicates that the implementation supports:

  - The following can be used in `Vk*PipelineCreateInfo`::`flags`:

    - `VK_PIPELINE_CREATE_FAIL_ON_PIPELINE_COMPILE_REQUIRED_BIT_EXT`

    - `VK_PIPELINE_CREATE_EARLY_RETURN_ON_FAILURE_BIT_EXT`

  - The following can be used in `VkPipelineCacheCreateInfo`::`flags`:

    - `VK_PIPELINE_CACHE_CREATE_EXTERNALLY_SYNCHRONIZED_BIT_EXT`

If the `VkPhysicalDevicePipelineCreationCacheControlFeaturesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceFeatures2, it is filled with values indicating whether the feature is supported. `VkPhysicalDevicePipelineCreationCacheControlFeaturesEXT` can also be used in the `pNext` chain of VkDeviceCreateInfo to enable features.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PIPELINE_CREATION_CACHE_CONTROL_FEATURES_EXT`

### 37.1. Feature Requirements

All Vulkan graphics implementations must support the following features:

- `robustBufferAccess`

- `multiview`, if Vulkan 1.1 is supported.

- `uniformBufferStandardLayout`, if Vulkan 1.2 or the `VK_KHR_uniform_buffer_standard_layout` extension is supported.

- `variablePointersStorageBuffer`, if the `VK_KHR_variable_pointers` extension is supported.

- `storageBuffer8BitAccess`, if the `VK_KHR_8bit_storage` extension is supported.

- If the descriptorIndexing feature is supported, or if the `VK_EXT_descriptor_indexing` extension is supported:

  - `shaderSampledImageArrayDynamicIndexing`

  - `shaderStorageBufferArrayDynamicIndexing`

  - `shaderUniformTexelBufferArrayDynamicIndexing`

  - `shaderStorageTexelBufferArrayDynamicIndexing`

  - `shaderSampledImageArrayNonUniformIndexing`

  - `shaderStorageBufferArrayNonUniformIndexing`

  - `shaderUniformTexelBufferArrayNonUniformIndexing`

  - `descriptorBindingSampledImageUpdateAfterBind`

  - `descriptorBindingStorageImageUpdateAfterBind`

  - `descriptorBindingStorageBufferUpdateAfterBind` (see also `robustBufferAccessUpdateAfterBind`)

  - `descriptorBindingUniformTexelBufferUpdateAfterBind` (see also `robustBufferAccessUpdateAfterBind`)

  - `descriptorBindingStorageTexelBufferUpdateAfterBind` (see also `robustBufferAccessUpdateAfterBind`)

  - `descriptorBindingUpdateUnusedWhilePending`

  - `descriptorBindingPartiallyBound`

  - `runtimeDescriptorArray`

- `inlineUniformBlock`, if the `VK_EXT_inline_uniform_block` extension is supported.

- `descriptorBindingInlineUniformBlockUpdateAfterBind`, if the `VK_EXT_inline_uniform_block` extension is supported; and if the `descriptorIndexing` feature is supported, or the `VK_EXT_descriptor_indexing` extension is supported.

- `scalarBlockLayout`, if the `VK_EXT_scalar_block_layout` extension is supported.

- `subgroupBroadcastDynamicId`, if Vulkan 1.2 is supported.

- `samplerMirrorClampToEdge`, if the `VK_KHR_sampler_mirror_clamp_to_edge` extension is supported.

- `drawIndirectCount`, if the `VK_KHR_draw_indirect_count` extension is supported.

- `samplerFilterMinmax`, if the `VK_EXT_sampler_filter_minmax` extension is supported.

- `shaderOutputViewportIndex`, if the `VK_EXT_shader_viewport_index_layer` extension is supported.

- `shaderOutputLayer`, if the `VK_EXT_shader_viewport_index_layer` extension is supported.

- `subgroupSizeControl`, if the `VK_EXT_subgroup_size_control` extension is supported.

- `computeFullSubgroups`, if the `VK_EXT_subgroup_size_control` extension is supported.

- `imagelessFramebuffer`, if Vulkan 1.2 is supported.

- `separateDepthStencilLayouts`, if Vulkan 1.2 is supported.

- `hostQueryReset`, if Vulkan 1.2 is supported.

- `timelineSemaphore`, if Vulkan 1.2 or the `VK_KHR_timeline_semaphore` extension is supported.

- If the `VK_KHR_ray_tracing` extension is supported:

  - `rayTracing`

  - `rayTracingIndirectTraceRays`

  - All the features required by the descriptorIndexing feature if Vulkan 1.2 is supported, or the `VK_EXT_descriptor_indexing` extension.

  - `bufferDeviceAddress` from Vulkan 1.2 or the `VK_KHR_buffer_device_address` extension.

  - `rayTracingPrimitiveCulling`, if `rayQuery` is supported.

- `pipelineCreationCacheControl`, if the `VK_EXT_pipeline_creation_cache_control` extension is supported.

All other features defined in the Specification are optional.

## 38. Limits

Limits are implementation-dependent minimums, maximums, and other device characteristics that an application may need to be aware of.

| Note Limits are reported via the basic VkPhysicalDeviceLimits structure, as well as the extensible structure `VkPhysicalDeviceProperties2`, which was added in `VK_KHR_get_physical_device_properties2` and included in Vulkan 1.1. When limits are added in future Vulkan versions or extensions, each extension should introduce one new limit structure, if needed. This structure can be added to the `pNext` chain of the `VkPhysicalDeviceProperties2` structure.

The `VkPhysicalDeviceLimits` structure is defined as:

    typedef struct VkPhysicalDeviceLimits {
        uint32_t              maxImageDimension1D;
        uint32_t              maxImageDimension2D;
        uint32_t              maxImageDimension3D;
        uint32_t              maxImageDimensionCube;
        uint32_t              maxImageArrayLayers;
        uint32_t              maxTexelBufferElements;
        uint32_t              maxUniformBufferRange;
        uint32_t              maxStorageBufferRange;
        uint32_t              maxPushConstantsSize;
        uint32_t              maxMemoryAllocationCount;
        uint32_t              maxSamplerAllocationCount;
        VkDeviceSize          bufferImageGranularity;
        VkDeviceSize          sparseAddressSpaceSize;
        uint32_t              maxBoundDescriptorSets;
        uint32_t              maxPerStageDescriptorSamplers;
        uint32_t              maxPerStageDescriptorUniformBuffers;
        uint32_t              maxPerStageDescriptorStorageBuffers;
        uint32_t              maxPerStageDescriptorSampledImages;
        uint32_t              maxPerStageDescriptorStorageImages;
        uint32_t              maxPerStageDescriptorInputAttachments;
        uint32_t              maxPerStageResources;
        uint32_t              maxDescriptorSetSamplers;
        uint32_t              maxDescriptorSetUniformBuffers;
        uint32_t              maxDescriptorSetUniformBuffersDynamic;
        uint32_t              maxDescriptorSetStorageBuffers;
        uint32_t              maxDescriptorSetStorageBuffersDynamic;
        uint32_t              maxDescriptorSetSampledImages;
        uint32_t              maxDescriptorSetStorageImages;
        uint32_t              maxDescriptorSetInputAttachments;
        uint32_t              maxVertexInputAttributes;
        uint32_t              maxVertexInputBindings;
        uint32_t              maxVertexInputAttributeOffset;
        uint32_t              maxVertexInputBindingStride;
        uint32_t              maxVertexOutputComponents;
        uint32_t              maxTessellationGenerationLevel;
        uint32_t              maxTessellationPatchSize;
        uint32_t              maxTessellationControlPerVertexInputComponents;
        uint32_t              maxTessellationControlPerVertexOutputComponents;
        uint32_t              maxTessellationControlPerPatchOutputComponents;
        uint32_t              maxTessellationControlTotalOutputComponents;
        uint32_t              maxTessellationEvaluationInputComponents;
        uint32_t              maxTessellationEvaluationOutputComponents;
        uint32_t              maxGeometryShaderInvocations;
        uint32_t              maxGeometryInputComponents;
        uint32_t              maxGeometryOutputComponents;
        uint32_t              maxGeometryOutputVertices;
        uint32_t              maxGeometryTotalOutputComponents;
        uint32_t              maxFragmentInputComponents;
        uint32_t              maxFragmentOutputAttachments;
        uint32_t              maxFragmentDualSrcAttachments;
        uint32_t              maxFragmentCombinedOutputResources;
        uint32_t              maxComputeSharedMemorySize;
        uint32_t              maxComputeWorkGroupCount[3];
        uint32_t              maxComputeWorkGroupInvocations;
        uint32_t              maxComputeWorkGroupSize[3];
        uint32_t              subPixelPrecisionBits;
        uint32_t              subTexelPrecisionBits;
        uint32_t              mipmapPrecisionBits;
        uint32_t              maxDrawIndexedIndexValue;
        uint32_t              maxDrawIndirectCount;
        float                 maxSamplerLodBias;
        float                 maxSamplerAnisotropy;
        uint32_t              maxViewports;
        uint32_t              maxViewportDimensions[2];
        float                 viewportBoundsRange[2];
        uint32_t              viewportSubPixelBits;
        size_t                minMemoryMapAlignment;
        VkDeviceSize          minTexelBufferOffsetAlignment;
        VkDeviceSize          minUniformBufferOffsetAlignment;
        VkDeviceSize          minStorageBufferOffsetAlignment;
        int32_t               minTexelOffset;
        uint32_t              maxTexelOffset;
        int32_t               minTexelGatherOffset;
        uint32_t              maxTexelGatherOffset;
        float                 minInterpolationOffset;
        float                 maxInterpolationOffset;
        uint32_t              subPixelInterpolationOffsetBits;
        uint32_t              maxFramebufferWidth;
        uint32_t              maxFramebufferHeight;
        uint32_t              maxFramebufferLayers;
        VkSampleCountFlags    framebufferColorSampleCounts;
        VkSampleCountFlags    framebufferDepthSampleCounts;
        VkSampleCountFlags    framebufferStencilSampleCounts;
        VkSampleCountFlags    framebufferNoAttachmentsSampleCounts;
        uint32_t              maxColorAttachments;
        VkSampleCountFlags    sampledImageColorSampleCounts;
        VkSampleCountFlags    sampledImageIntegerSampleCounts;
        VkSampleCountFlags    sampledImageDepthSampleCounts;
        VkSampleCountFlags    sampledImageStencilSampleCounts;
        VkSampleCountFlags    storageImageSampleCounts;
        uint32_t              maxSampleMaskWords;
        VkBool32              timestampComputeAndGraphics;
        float                 timestampPeriod;
        uint32_t              maxClipDistances;
        uint32_t              maxCullDistances;
        uint32_t              maxCombinedClipAndCullDistances;
        uint32_t              discreteQueuePriorities;
        float                 pointSizeRange[2];
        float                 lineWidthRange[2];
        float                 pointSizeGranularity;
        float                 lineWidthGranularity;
        VkBool32              strictLines;
        VkBool32              standardSampleLocations;
        VkDeviceSize          optimalBufferCopyOffsetAlignment;
        VkDeviceSize          optimalBufferCopyRowPitchAlignment;
        VkDeviceSize          nonCoherentAtomSize;
    } VkPhysicalDeviceLimits;

The `VkPhysicalDeviceLimits` are properties of the physical device. These are available in the `limits` member of the VkPhysicalDeviceProperties structure which is returned from vkGetPhysicalDeviceProperties.

- `maxImageDimension1D` is the maximum dimension (`width`) supported for all images created with an `imageType` of `VK_IMAGE_TYPE_1D`.

- `maxImageDimension2D` is the maximum dimension (`width` or `height`) supported for all images created with an `imageType` of `VK_IMAGE_TYPE_2D` and without `VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT` set in `flags`.

- `maxImageDimension3D` is the maximum dimension (`width`, `height`, or `depth`) supported for all images created with an `imageType` of `VK_IMAGE_TYPE_3D`.

- `maxImageDimensionCube` is the maximum dimension (`width` or `height`) supported for all images created with an `imageType` of `VK_IMAGE_TYPE_2D` and with `VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT` set in `flags`.

- `maxImageArrayLayers` is the maximum number of layers (`arrayLayers`) for an image.

- `maxTexelBufferElements` is the maximum number of addressable texels for a buffer view created on a buffer which was created with the `VK_BUFFER_USAGE_UNIFORM_TEXEL_BUFFER_BIT` or `VK_BUFFER_USAGE_STORAGE_TEXEL_BUFFER_BIT` set in the `usage` member of the `VkBufferCreateInfo` structure.

- `maxUniformBufferRange` is the maximum value that can be specified in the `range` member of any VkDescriptorBufferInfo structures passed to a call to vkUpdateDescriptorSets for descriptors of type `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER` or `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC`.

- `maxStorageBufferRange` is the maximum value that can be specified in the `range` member of any VkDescriptorBufferInfo structures passed to a call to vkUpdateDescriptorSets for descriptors of type `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER` or `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC`.

- `maxPushConstantsSize` is the maximum size, in bytes, of the pool of push constant memory. For each of the push constant ranges indicated by the `pPushConstantRanges` member of the `VkPipelineLayoutCreateInfo` structure, (`offset` + `size`) must be less than or equal to this limit.

- `maxMemoryAllocationCount` is the maximum number of device memory allocations, as created by vkAllocateMemory, which can simultaneously exist.

- `maxSamplerAllocationCount` is the maximum number of sampler objects, as created by vkCreateSampler, which can simultaneously exist on a device.

- `bufferImageGranularity` is the granularity, in bytes, at which buffer or linear image resources, and optimal image resources can be bound to adjacent offsets in the same `VkDeviceMemory` object without aliasing. See Buffer-Image Granularity for more details.

- `sparseAddressSpaceSize` is the total amount of address space available, in bytes, for sparse memory resources. This is an upper bound on the sum of the size of all sparse resources, regardless of whether any memory is bound to them.

- `maxBoundDescriptorSets` is the maximum number of descriptor sets that can be simultaneously used by a pipeline. All `DescriptorSet` decorations in shader modules must have a value less than `maxBoundDescriptorSets`. See Descriptor Sets.

- `maxPerStageDescriptorSamplers` is the maximum number of samplers that can be accessible to a single shader stage in a pipeline layout. Descriptors with a type of `VK_DESCRIPTOR_TYPE_SAMPLER` or `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER` count against this limit. Only descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set count against this limit. A descriptor is accessible to a shader stage when the `stageFlags` member of the `VkDescriptorSetLayoutBinding` structure has the bit for that shader stage set. See Sampler and Combined Image Sampler.

- `maxPerStageDescriptorUniformBuffers` is the maximum number of uniform buffers that can be accessible to a single shader stage in a pipeline layout. Descriptors with a type of `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER` or `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC` count against this limit. Only descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set count against this limit. A descriptor is accessible to a shader stage when the `stageFlags` member of the `VkDescriptorSetLayoutBinding` structure has the bit for that shader stage set. See Uniform Buffer and Dynamic Uniform Buffer.

- `maxPerStageDescriptorStorageBuffers` is the maximum number of storage buffers that can be accessible to a single shader stage in a pipeline layout. Descriptors with a type of `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER` or `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC` count against this limit. Only descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set count against this limit. A descriptor is accessible to a pipeline shader stage when the `stageFlags` member of the `VkDescriptorSetLayoutBinding` structure has the bit for that shader stage set. See Storage Buffer and Dynamic Storage Buffer.

- `maxPerStageDescriptorSampledImages` is the maximum number of sampled images that can be accessible to a single shader stage in a pipeline layout. Descriptors with a type of `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE`, or `VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER` count against this limit. Only descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set count against this limit. A descriptor is accessible to a pipeline shader stage when the `stageFlags` member of the `VkDescriptorSetLayoutBinding` structure has the bit for that shader stage set. See Combined Image Sampler, Sampled Image, and Uniform Texel Buffer.

- `maxPerStageDescriptorStorageImages` is the maximum number of storage images that can be accessible to a single shader stage in a pipeline layout. Descriptors with a type of `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE`, or `VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER` count against this limit. Only descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set count against this limit. A descriptor is accessible to a pipeline shader stage when the `stageFlags` member of the `VkDescriptorSetLayoutBinding` structure has the bit for that shader stage set. See Storage Image, and Storage Texel Buffer.

- `maxPerStageDescriptorInputAttachments` is the maximum number of input attachments that can be accessible to a single shader stage in a pipeline layout. Descriptors with a type of `VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT` count against this limit. Only descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set count against this limit. A descriptor is accessible to a pipeline shader stage when the `stageFlags` member of the `VkDescriptorSetLayoutBinding` structure has the bit for that shader stage set. These are only supported for the fragment stage. See Input Attachment.

- `maxPerStageResources` is the maximum number of resources that can be accessible to a single shader stage in a pipeline layout. Descriptors with a type of `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE`, `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE`, `VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER`, `VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER`, `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER`, `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER`, `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC`, `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC`, or `VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT` count against this limit. Only descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set count against this limit. For the fragment shader stage the framebuffer color attachments also count against this limit.

- `maxDescriptorSetSamplers` is the maximum number of samplers that can be included in a pipeline layout. Descriptors with a type of `VK_DESCRIPTOR_TYPE_SAMPLER` or `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER` count against this limit. Only descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set count against this limit. See Sampler and Combined Image Sampler.

- `maxDescriptorSetUniformBuffers` is the maximum number of uniform buffers that can be included in a pipeline layout. Descriptors with a type of `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER` or `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC` count against this limit. Only descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set count against this limit. See Uniform Buffer and Dynamic Uniform Buffer.

- `maxDescriptorSetUniformBuffersDynamic` is the maximum number of dynamic uniform buffers that can be included in a pipeline layout. Descriptors with a type of `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC` count against this limit. Only descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set count against this limit. See Dynamic Uniform Buffer.

- `maxDescriptorSetStorageBuffers` is the maximum number of storage buffers that can be included in a pipeline layout. Descriptors with a type of `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER` or `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC` count against this limit. Only descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set count against this limit. See Storage Buffer and Dynamic Storage Buffer.

- `maxDescriptorSetStorageBuffersDynamic` is the maximum number of dynamic storage buffers that can be included in a pipeline layout. Descriptors with a type of `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC` count against this limit. Only descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set count against this limit. See Dynamic Storage Buffer.

- `maxDescriptorSetSampledImages` is the maximum number of sampled images that can be included in a pipeline layout. Descriptors with a type of `VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER`, `VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE`, or `VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER` count against this limit. Only descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set count against this limit. See Combined Image Sampler, Sampled Image, and Uniform Texel Buffer.

- `maxDescriptorSetStorageImages` is the maximum number of storage images that can be included in a pipeline layout. Descriptors with a type of `VK_DESCRIPTOR_TYPE_STORAGE_IMAGE`, or `VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER` count against this limit. Only descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set count against this limit. See Storage Image, and Storage Texel Buffer.

- `maxDescriptorSetInputAttachments` is the maximum number of input attachments that can be included in a pipeline layout. Descriptors with a type of `VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT` count against this limit. Only descriptors in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set count against this limit. See Input Attachment.

- `maxVertexInputAttributes` is the maximum number of vertex input attributes that can be specified for a graphics pipeline. These are described in the array of `VkVertexInputAttributeDescription` structures that are provided at graphics pipeline creation time via the `pVertexAttributeDescriptions` member of the `VkPipelineVertexInputStateCreateInfo` structure. See Vertex Attributes and Vertex Input Description.

- `maxVertexInputBindings` is the maximum number of vertex buffers that can be specified for providing vertex attributes to a graphics pipeline. These are described in the array of `VkVertexInputBindingDescription` structures that are provided at graphics pipeline creation time via the `pVertexBindingDescriptions` member of the `VkPipelineVertexInputStateCreateInfo` structure. The `binding` member of `VkVertexInputBindingDescription` must be less than this limit. See Vertex Input Description.

- `maxVertexInputAttributeOffset` is the maximum vertex input attribute offset that can be added to the vertex input binding stride. The `offset` member of the `VkVertexInputAttributeDescription` structure must be less than or equal to this limit. See Vertex Input Description.

- `maxVertexInputBindingStride` is the maximum vertex input binding stride that can be specified in a vertex input binding. The `stride` member of the `VkVertexInputBindingDescription` structure must be less than or equal to this limit. See Vertex Input Description.

- `maxVertexOutputComponents` is the maximum number of components of output variables which can be output by a vertex shader. See Vertex Shaders.

- `maxTessellationGenerationLevel` is the maximum tessellation generation level supported by the fixed-function tessellation primitive generator. See Tessellation.

- `maxTessellationPatchSize` is the maximum patch size, in vertices, of patches that can be processed by the tessellation control shader and tessellation primitive generator. The `patchControlPoints` member of the `VkPipelineTessellationStateCreateInfo` structure specified at pipeline creation time and the value provided in the `OutputVertices` execution mode of shader modules must be less than or equal to this limit. See Tessellation.

- `maxTessellationControlPerVertexInputComponents` is the maximum number of components of input variables which can be provided as per-vertex inputs to the tessellation control shader stage.

- `maxTessellationControlPerVertexOutputComponents` is the maximum number of components of per-vertex output variables which can be output from the tessellation control shader stage.

- `maxTessellationControlPerPatchOutputComponents` is the maximum number of components of per-patch output variables which can be output from the tessellation control shader stage.

- `maxTessellationControlTotalOutputComponents` is the maximum total number of components of per-vertex and per-patch output variables which can be output from the tessellation control shader stage.

- `maxTessellationEvaluationInputComponents` is the maximum number of components of input variables which can be provided as per-vertex inputs to the tessellation evaluation shader stage.

- `maxTessellationEvaluationOutputComponents` is the maximum number of components of per-vertex output variables which can be output from the tessellation evaluation shader stage.

- `maxGeometryShaderInvocations` is the maximum invocation count supported for instanced geometry shaders. The value provided in the `Invocations` execution mode of shader modules must be less than or equal to this limit. See Geometry Shading.

- `maxGeometryInputComponents` is the maximum number of components of input variables which can be provided as inputs to the geometry shader stage.

- `maxGeometryOutputComponents` is the maximum number of components of output variables which can be output from the geometry shader stage.

- `maxGeometryOutputVertices` is the maximum number of vertices which can be emitted by any geometry shader.

- `maxGeometryTotalOutputComponents` is the maximum total number of components of output, across all emitted vertices, which can be output from the geometry shader stage.

- `maxFragmentInputComponents` is the maximum number of components of input variables which can be provided as inputs to the fragment shader stage.

- `maxFragmentOutputAttachments` is the maximum number of output attachments which can be written to by the fragment shader stage.

- `maxFragmentDualSrcAttachments` is the maximum number of output attachments which can be written to by the fragment shader stage when blending is enabled and one of the dual source blend modes is in use. See Dual-Source Blending and dualSrcBlend.

- `maxFragmentCombinedOutputResources` is the total number of storage buffers, storage images, and output buffers which can be used in the fragment shader stage.

- `maxComputeSharedMemorySize` is the maximum total storage size, in bytes, available for variables declared with the `Workgroup` storage class in shader modules (or with the `shared` storage qualifier in GLSL) in the compute shader stage. The amount of storage consumed by the variables declared with the `Workgroup` storage class is implementation-dependent. However, the amount of storage consumed may not exceed the largest block size that would be obtained if all active variables declared with `Workgroup` storage class were assigned offsets in an arbitrary order by successively taking the smallest valid offset according to the Standard Storage Buffer Layout rules. (This is equivalent to using the GLSL std430 layout rules.)

- `maxComputeWorkGroupCount`[3] is the maximum number of local workgroups that can be dispatched by a single dispatch command. These three values represent the maximum number of local workgroups for the X, Y, and Z dimensions, respectively. The workgroup count parameters to the dispatch commands must be less than or equal to the corresponding limit. See Dispatching Commands.

- `maxComputeWorkGroupInvocations` is the maximum total number of compute shader invocations in a single local workgroup. The product of the X, Y, and Z sizes, as specified by the `LocalSize` execution mode in shader modules or by the object decorated by the `WorkgroupSize` decoration, must be less than or equal to this limit.

- `maxComputeWorkGroupSize`[3] is the maximum size of a local compute workgroup, per dimension. These three values represent the maximum local workgroup size in the X, Y, and Z dimensions, respectively. The `x`, `y`, and `z` sizes, as specified by the `LocalSize` execution mode or by the object decorated by the `WorkgroupSize` decoration in shader modules, must be less than or equal to the corresponding limit.

- `subPixelPrecisionBits` is the number of bits of subpixel precision in framebuffer coordinates xf and yf. See Rasterization.

- `subTexelPrecisionBits` is the number of bits of precision in the division along an axis of an image used for minification and magnification filters. 2`subTexelPrecisionBits` is the actual number of divisions along each axis of the image represented. Sub-texel values calculated during image sampling will snap to these locations when generating the filtered results.

- `mipmapPrecisionBits` is the number of bits of division that the LOD calculation for mipmap fetching get snapped to when determining the contribution from each mip level to the mip filtered results. 2`mipmapPrecisionBits` is the actual number of divisions.

- `maxDrawIndexedIndexValue` is the maximum index value that can be used for indexed draw calls when using 32-bit indices. This excludes the primitive restart index value of 0xFFFFFFFF. See fullDrawIndexUint32.

- `maxDrawIndirectCount` is the maximum draw count that is supported for indirect draw calls. See multiDrawIndirect.

- `maxSamplerLodBias` is the maximum absolute sampler LOD bias. The sum of the `mipLodBias` member of the `VkSamplerCreateInfo` structure and the `Bias` operand of image sampling operations in shader modules (or 0 if no `Bias` operand is provided to an image sampling operation) are clamped to the range [-`maxSamplerLodBias`,+`maxSamplerLodBias`]. See [samplers-mipLodBias].

- `maxSamplerAnisotropy` is the maximum degree of sampler anisotropy. The maximum degree of anisotropic filtering used for an image sampling operation is the minimum of the `maxAnisotropy` member of the `VkSamplerCreateInfo` structure and this limit. See [samplers-maxAnisotropy].

- `maxViewports` is the maximum number of active viewports. The `viewportCount` member of the `VkPipelineViewportStateCreateInfo` structure that is provided at pipeline creation must be less than or equal to this limit.

- `maxViewportDimensions`[2] are the maximum viewport dimensions in the X (width) and Y (height) dimensions, respectively. The maximum viewport dimensions must be greater than or equal to the largest image which can be created and used as a framebuffer attachment. See Controlling the Viewport.

- `viewportBoundsRange`[2] is the [minimum, maximum] range that the corners of a viewport must be contained in. This range must be at least [-2 × `size`, 2 × `size` - 1], where `size` = max(`maxViewportDimensions`[0], `maxViewportDimensions`[1]). See Controlling the Viewport.

  | Note The intent of the `viewportBoundsRange` limit is to allow a maximum sized viewport to be arbitrarily shifted relative to the output target as long as at least some portion intersects. This would give a bounds limit of [-`size` + 1, 2 × `size` - 1] which would allow all possible non-empty-set intersections of the output target and the viewport. Since these numbers are typically powers of two, picking the signed number range using the smallest possible number of bits ends up with the specified range.

- `viewportSubPixelBits` is the number of bits of subpixel precision for viewport bounds. The subpixel precision that floating-point viewport bounds are interpreted at is given by this limit.

- `minMemoryMapAlignment` is the minimum required alignment, in bytes, of host visible memory allocations within the host address space. When mapping a memory allocation with vkMapMemory, subtracting `offset` bytes from the returned pointer will always produce an integer multiple of this limit. See Host Access to Device Memory Objects.

- `minTexelBufferOffsetAlignment` is the minimum required alignment, in bytes, for the `offset` member of the `VkBufferViewCreateInfo` structure for texel buffers. If texelBufferAlignment is enabled, this limit is equivalent to the maximum of the `uniformTexelBufferOffsetAlignmentBytes` and `storageTexelBufferOffsetAlignmentBytes` members of VkPhysicalDeviceTexelBufferAlignmentPropertiesEXT, but smaller alignment is optionally: allowed by `storageTexelBufferOffsetSingleTexelAlignment` and `uniformTexelBufferOffsetSingleTexelAlignment`. If texelBufferAlignment is not enabled, VkBufferViewCreateInfo::`offset` must be a multiple of this value.

- `minUniformBufferOffsetAlignment` is the minimum required alignment, in bytes, for the `offset` member of the `VkDescriptorBufferInfo` structure for uniform buffers. When a descriptor of type `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER` or `VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC` is updated, the `offset` must be an integer multiple of this limit. Similarly, dynamic offsets for uniform buffers must be multiples of this limit.

- `minStorageBufferOffsetAlignment` is the minimum required alignment, in bytes, for the `offset` member of the `VkDescriptorBufferInfo` structure for storage buffers. When a descriptor of type `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER` or `VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC` is updated, the `offset` must be an integer multiple of this limit. Similarly, dynamic offsets for storage buffers must be multiples of this limit.

- `minTexelOffset` is the minimum offset value for the `ConstOffset` image operand of any of the `OpImageSample`* or `OpImageFetch`* image instructions.

- `maxTexelOffset` is the maximum offset value for the `ConstOffset` image operand of any of the `OpImageSample`* or `OpImageFetch`* image instructions.

- `minTexelGatherOffset` is the minimum offset value for the `Offset`, `ConstOffset`, or `ConstOffsets` image operands of any of the `OpImage`*`Gather` image instructions.

- `maxTexelGatherOffset` is the maximum offset value for the `Offset`, `ConstOffset`, or `ConstOffsets` image operands of any of the `OpImage`*`Gather` image instructions.

- `minInterpolationOffset` is the minimum negative offset value for the `offset` operand of the `InterpolateAtOffset` extended instruction.

- `maxInterpolationOffset` is the maximum positive offset value for the `offset` operand of the `InterpolateAtOffset` extended instruction.

- `subPixelInterpolationOffsetBits` is the number of subpixel fractional bits that the `x` and `y` offsets to the `InterpolateAtOffset` extended instruction may be rounded to as fixed-point values.

- `maxFramebufferWidth` is the maximum width for a framebuffer. The `width` member of the `VkFramebufferCreateInfo` structure must be less than or equal to this limit.

- `maxFramebufferHeight` is the maximum height for a framebuffer. The `height` member of the `VkFramebufferCreateInfo` structure must be less than or equal to this limit.

- `maxFramebufferLayers` is the maximum layer count for a layered framebuffer. The `layers` member of the `VkFramebufferCreateInfo` structure must be less than or equal to this limit.

- `framebufferColorSampleCounts` is a bitmask1 of VkSampleCountFlagBits indicating the color sample counts that are supported for all framebuffer color attachments with floating- or fixed-point formats. There is no limit that specifies the color sample counts that are supported for all color attachments with integer formats.

- `framebufferDepthSampleCounts` is a bitmask1 of VkSampleCountFlagBits indicating the supported depth sample counts for all framebuffer depth/stencil attachments, when the format includes a depth component.

- `framebufferStencilSampleCounts` is a bitmask1 of VkSampleCountFlagBits indicating the supported stencil sample counts for all framebuffer depth/stencil attachments, when the format includes a stencil component.

- `framebufferNoAttachmentsSampleCounts` is a bitmask1 of VkSampleCountFlagBits indicating the supported sample counts for a framebuffer with no attachments.

- `maxColorAttachments` is the maximum number of color attachments that can be used by a subpass in a render pass. The `colorAttachmentCount` member of the `VkSubpassDescription` structure must be less than or equal to this limit.

- `sampledImageColorSampleCounts` is a bitmask1 of VkSampleCountFlagBits indicating the sample counts supported for all 2D images created with `VK_IMAGE_TILING_OPTIMAL`, `usage` containing `VK_IMAGE_USAGE_SAMPLED_BIT`, and a non-integer color format.

- `sampledImageIntegerSampleCounts` is a bitmask1 of VkSampleCountFlagBits indicating the sample counts supported for all 2D images created with `VK_IMAGE_TILING_OPTIMAL`, `usage` containing `VK_IMAGE_USAGE_SAMPLED_BIT`, and an integer color format.

- `sampledImageDepthSampleCounts` is a bitmask1 of VkSampleCountFlagBits indicating the sample counts supported for all 2D images created with `VK_IMAGE_TILING_OPTIMAL`, `usage` containing `VK_IMAGE_USAGE_SAMPLED_BIT`, and a depth format.

- `sampledImageStencilSampleCounts` is a bitmask1 of VkSampleCountFlagBits indicating the sample supported for all 2D images created with `VK_IMAGE_TILING_OPTIMAL`, `usage` containing `VK_IMAGE_USAGE_SAMPLED_BIT`, and a stencil format.

- `storageImageSampleCounts` is a bitmask1 of VkSampleCountFlagBits indicating the sample counts supported for all 2D images created with `VK_IMAGE_TILING_OPTIMAL`, and `usage` containing `VK_IMAGE_USAGE_STORAGE_BIT`.

- `maxSampleMaskWords` is the maximum number of array elements of a variable decorated with the `SampleMask` built-in decoration.

- `timestampComputeAndGraphics` specifies support for timestamps on all graphics and compute queues. If this limit is set to `VK_TRUE`, all queues that advertise the `VK_QUEUE_GRAPHICS_BIT` or `VK_QUEUE_COMPUTE_BIT` in the `VkQueueFamilyProperties`::`queueFlags` support `VkQueueFamilyProperties`::`timestampValidBits` of at least 36. See Timestamp Queries.

- `timestampPeriod` is the number of nanoseconds required for a timestamp query to be incremented by 1. See Timestamp Queries.

- `maxClipDistances` is the maximum number of clip distances that can be used in a single shader stage. The size of any array declared with the `ClipDistance` built-in decoration in a shader module must be less than or equal to this limit.

- `maxCullDistances` is the maximum number of cull distances that can be used in a single shader stage. The size of any array declared with the `CullDistance` built-in decoration in a shader module must be less than or equal to this limit.

- `maxCombinedClipAndCullDistances` is the maximum combined number of clip and cull distances that can be used in a single shader stage. The sum of the sizes of any pair of arrays declared with the `ClipDistance` and `CullDistance` built-in decoration used by a single shader stage in a shader module must be less than or equal to this limit.

- `discreteQueuePriorities` is the number of discrete priorities that can be assigned to a queue based on the value of each member of `VkDeviceQueueCreateInfo`::`pQueuePriorities`. This must be at least 2, and levels must be spread evenly over the range, with at least one level at 1.0, and another at 0.0. See Queue Priority.

- `pointSizeRange`[2] is the range [`minimum`,`maximum`] of supported sizes for points. Values written to variables decorated with the `PointSize` built-in decoration are clamped to this range.

- `lineWidthRange`[2] is the range [`minimum`,`maximum`] of supported widths for lines. Values specified by the `lineWidth` member of the `VkPipelineRasterizationStateCreateInfo` or the `lineWidth` parameter to `vkCmdSetLineWidth` are clamped to this range.

- `pointSizeGranularity` is the granularity of supported point sizes. Not all point sizes in the range defined by `pointSizeRange` are supported. This limit specifies the granularity (or increment) between successive supported point sizes.

- `lineWidthGranularity` is the granularity of supported line widths. Not all line widths in the range defined by `lineWidthRange` are supported. This limit specifies the granularity (or increment) between successive supported line widths.

- `strictLines` specifies whether lines are rasterized according to the preferred method of rasterization. If set to `VK_FALSE`, lines may be rasterized under a relaxed set of rules. If set to `VK_TRUE`, lines are rasterized as per the strict definition. See Basic Line Segment Rasterization.

- `standardSampleLocations` specifies whether rasterization uses the standard sample locations as documented in Multisampling. If set to `VK_TRUE`, the implementation uses the documented sample locations. If set to `VK_FALSE`, the implementation may use different sample locations.

- `optimalBufferCopyOffsetAlignment` is the optimal buffer offset alignment in bytes for `vkCmdCopyBufferToImage` and `vkCmdCopyImageToBuffer`. The per texel alignment requirements are enforced, but applications should use the optimal alignment for optimal performance and power use.

- `optimalBufferCopyRowPitchAlignment` is the optimal buffer row pitch alignment in bytes for `vkCmdCopyBufferToImage` and `vkCmdCopyImageToBuffer`. Row pitch is the number of bytes between texels with the same X coordinate in adjacent rows (Y coordinates differ by one). The per texel alignment requirements are enforced, but applications should use the optimal alignment for optimal performance and power use.

- `nonCoherentAtomSize` is the size and alignment in bytes that bounds concurrent access to host-mapped device memory.

1

  For all bitmasks of VkSampleCountFlagBits, the sample count limits defined above represent the minimum supported sample counts for each image type. Individual images may support additional sample counts, which are queried using vkGetPhysicalDeviceImageFormatProperties as described in Supported Sample Counts.

Bits which may be set in the sample count limits returned by VkPhysicalDeviceLimits, as well as in other queries and structures representing image sample counts, are:

    typedef enum VkSampleCountFlagBits {
        VK_SAMPLE_COUNT_1_BIT = 0x00000001,
        VK_SAMPLE_COUNT_2_BIT = 0x00000002,
        VK_SAMPLE_COUNT_4_BIT = 0x00000004,
        VK_SAMPLE_COUNT_8_BIT = 0x00000008,
        VK_SAMPLE_COUNT_16_BIT = 0x00000010,
        VK_SAMPLE_COUNT_32_BIT = 0x00000020,
        VK_SAMPLE_COUNT_64_BIT = 0x00000040,
        VK_SAMPLE_COUNT_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkSampleCountFlagBits;

- `VK_SAMPLE_COUNT_1_BIT` specifies an image with one sample per pixel.

- `VK_SAMPLE_COUNT_2_BIT` specifies an image with 2 samples per pixel.

- `VK_SAMPLE_COUNT_4_BIT` specifies an image with 4 samples per pixel.

- `VK_SAMPLE_COUNT_8_BIT` specifies an image with 8 samples per pixel.

- `VK_SAMPLE_COUNT_16_BIT` specifies an image with 16 samples per pixel.

- `VK_SAMPLE_COUNT_32_BIT` specifies an image with 32 samples per pixel.

- `VK_SAMPLE_COUNT_64_BIT` specifies an image with 64 samples per pixel.

    typedef VkFlags VkSampleCountFlags;

`VkSampleCountFlags` is a bitmask type for setting a mask of zero or more VkSampleCountFlagBits.

The `VkPhysicalDevicePushDescriptorPropertiesKHR` structure is defined as:

    typedef struct VkPhysicalDevicePushDescriptorPropertiesKHR {
        VkStructureType    sType;
        void*              pNext;
        uint32_t           maxPushDescriptors;
    } VkPhysicalDevicePushDescriptorPropertiesKHR;

The members of the `VkPhysicalDevicePushDescriptorPropertiesKHR` structure describe the following implementation-dependent limits:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `maxPushDescriptors` is the maximum number of descriptors that can be used in a descriptor set created with `VK_DESCRIPTOR_SET_LAYOUT_CREATE_PUSH_DESCRIPTOR_BIT_KHR` set.

If the `VkPhysicalDevicePushDescriptorPropertiesKHR` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PUSH_DESCRIPTOR_PROPERTIES_KHR`

The `VkPhysicalDeviceMultiviewProperties` structure is defined as:

    typedef struct VkPhysicalDeviceMultiviewProperties {
        VkStructureType    sType;
        void*              pNext;
        uint32_t           maxMultiviewViewCount;
        uint32_t           maxMultiviewInstanceIndex;
    } VkPhysicalDeviceMultiviewProperties;

or the equivalent

    typedef VkPhysicalDeviceMultiviewProperties VkPhysicalDeviceMultiviewPropertiesKHR;

The members of the `VkPhysicalDeviceMultiviewProperties` structure describe the following implementation-dependent limits:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `maxMultiviewViewCount` is one greater than the maximum view index that can be used in a subpass.

- `maxMultiviewInstanceIndex` is the maximum valid value of instance index allowed to be generated by a drawing command recorded within a subpass of a multiview render pass instance.

If the `VkPhysicalDeviceMultiviewProperties` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_PROPERTIES`

The `VkPhysicalDeviceFloatControlsProperties` structure is defined as:

    typedef struct VkPhysicalDeviceFloatControlsProperties {
        VkStructureType                      sType;
        void*                                pNext;
        VkShaderFloatControlsIndependence    denormBehaviorIndependence;
        VkShaderFloatControlsIndependence    roundingModeIndependence;
        VkBool32                             shaderSignedZeroInfNanPreserveFloat16;
        VkBool32                             shaderSignedZeroInfNanPreserveFloat32;
        VkBool32                             shaderSignedZeroInfNanPreserveFloat64;
        VkBool32                             shaderDenormPreserveFloat16;
        VkBool32                             shaderDenormPreserveFloat32;
        VkBool32                             shaderDenormPreserveFloat64;
        VkBool32                             shaderDenormFlushToZeroFloat16;
        VkBool32                             shaderDenormFlushToZeroFloat32;
        VkBool32                             shaderDenormFlushToZeroFloat64;
        VkBool32                             shaderRoundingModeRTEFloat16;
        VkBool32                             shaderRoundingModeRTEFloat32;
        VkBool32                             shaderRoundingModeRTEFloat64;
        VkBool32                             shaderRoundingModeRTZFloat16;
        VkBool32                             shaderRoundingModeRTZFloat32;
        VkBool32                             shaderRoundingModeRTZFloat64;
    } VkPhysicalDeviceFloatControlsProperties;

or the equivalent

    typedef VkPhysicalDeviceFloatControlsProperties VkPhysicalDeviceFloatControlsPropertiesKHR;

The members of the `VkPhysicalDeviceFloatControlsProperties` structure describe the following implementation-dependent limits:

- `denormBehaviorIndependence` is a VkShaderFloatControlsIndependence value indicating whether, and how, denorm behavior can be set independently for different bit widths.

- `roundingModeIndependence` is a VkShaderFloatControlsIndependence value indicating whether, and how, rounding modes can be set independently for different bit widths.

- `shaderSignedZeroInfNanPreserveFloat16` is a boolean value indicating whether sign of a zero, Nans and \(\pm\infty\) can be preserved in 16-bit floating-point computations. It also indicates whether the `SignedZeroInfNanPreserve` execution mode can be used for 16-bit floating-point types.

- `shaderSignedZeroInfNanPreserveFloat32` is a boolean value indicating whether sign of a zero, Nans and \(\pm\infty\) can be preserved in 32-bit floating-point computations. It also indicates whether the `SignedZeroInfNanPreserve` execution mode can be used for 32-bit floating-point types.

- `shaderSignedZeroInfNanPreserveFloat64` is a boolean value indicating whether sign of a zero, Nans and \(\pm\infty\) can be preserved in 64-bit floating-point computations. It also indicates whether the `SignedZeroInfNanPreserve` execution mode can be used for 64-bit floating-point types.

- `shaderDenormPreserveFloat16` is a boolean value indicating whether denormals can be preserved in 16-bit floating-point computations. It also indicates whether the `DenormPreserve` execution mode can be used for 16-bit floating-point types.

- `shaderDenormPreserveFloat32` is a boolean value indicating whether denormals can be preserved in 32-bit floating-point computations. It also indicates whether the `DenormPreserve` execution mode can be used for 32-bit floating-point types.

- `shaderDenormPreserveFloat64` is a boolean value indicating whether denormals can be preserved in 64-bit floating-point computations. It also indicates whether the `DenormPreserve` execution mode can be used for 64-bit floating-point types.

- `shaderDenormFlushToZeroFloat16` is a boolean value indicating whether denormals can be flushed to zero in 16-bit floating-point computations. It also indicates whether the `DenormFlushToZero` execution mode can be used for 16-bit floating-point types.

- `shaderDenormFlushToZeroFloat32` is a boolean value indicating whether denormals can be flushed to zero in 32-bit floating-point computations. It also indicates whether the `DenormFlushToZero` execution mode can be used for 32-bit floating-point types.

- `shaderDenormFlushToZeroFloat64` is a boolean value indicating whether denormals can be flushed to zero in 64-bit floating-point computations. It also indicates whether the `DenormFlushToZero` execution mode can be used for 64-bit floating-point types.

- `shaderRoundingModeRTEFloat16` is a boolean value indicating whether an implementation supports the round-to-nearest-even rounding mode for 16-bit floating-point arithmetic and conversion instructions. It also indicates whether the `RoundingModeRTE` execution mode can be used for 16-bit floating-point types.

- `shaderRoundingModeRTEFloat32` is a boolean value indicating whether an implementation supports the round-to-nearest-even rounding mode for 32-bit floating-point arithmetic and conversion instructions. It also indicates whether the `RoundingModeRTE` execution mode can be used for 32-bit floating-point types.

- `shaderRoundingModeRTEFloat64` is a boolean value indicating whether an implementation supports the round-to-nearest-even rounding mode for 64-bit floating-point arithmetic and conversion instructions. It also indicates whether the `RoundingModeRTE` execution mode can be used for 64-bit floating-point types.

- `shaderRoundingModeRTZFloat16` is a boolean value indicating whether an implementation supports the round-towards-zero rounding mode for 16-bit floating-point arithmetic and conversion instructions. It also indicates whether the `RoundingModeRTZ` execution mode can be used for 16-bit floating-point types.

- `shaderRoundingModeRTZFloat32` is a boolean value indicating whether an implementation supports the round-towards-zero rounding mode for 32-bit floating-point arithmetic and conversion instructions. It also indicates whether the `RoundingModeRTZ` execution mode can be used for 32-bit floating-point types.

- `shaderRoundingModeRTZFloat64` is a boolean value indicating whether an implementation supports the round-towards-zero rounding mode for 64-bit floating-point arithmetic and conversion instructions. It also indicates whether the `RoundingModeRTZ` execution mode can be used for 64-bit floating-point types.

| editing-note Implementations may not be able to control behavior of denorms for floating-point atomics. This needs to be taken into account when such atomics will be added to Vulkan.

If the `VkPhysicalDeviceFloatControlsProperties` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FLOAT_CONTROLS_PROPERTIES`

Values which may be returned in the `denormBehaviorIndependence` and `roundingModeIndependence` fields of VkPhysicalDeviceFloatControlsProperties are:

    typedef enum VkShaderFloatControlsIndependence {
        VK_SHADER_FLOAT_CONTROLS_INDEPENDENCE_32_BIT_ONLY = 0,
        VK_SHADER_FLOAT_CONTROLS_INDEPENDENCE_ALL = 1,
        VK_SHADER_FLOAT_CONTROLS_INDEPENDENCE_NONE = 2,
        VK_SHADER_FLOAT_CONTROLS_INDEPENDENCE_32_BIT_ONLY_KHR = VK_SHADER_FLOAT_CONTROLS_INDEPENDENCE_32_BIT_ONLY,
        VK_SHADER_FLOAT_CONTROLS_INDEPENDENCE_ALL_KHR = VK_SHADER_FLOAT_CONTROLS_INDEPENDENCE_ALL,
        VK_SHADER_FLOAT_CONTROLS_INDEPENDENCE_NONE_KHR = VK_SHADER_FLOAT_CONTROLS_INDEPENDENCE_NONE,
        VK_SHADER_FLOAT_CONTROLS_INDEPENDENCE_MAX_ENUM = 0x7FFFFFFF
    } VkShaderFloatControlsIndependence;

- `VK_SHADER_FLOAT_CONTROLS_INDEPENDENCE_32_BIT_ONLY` specifies that shader float controls for 32-bit floating point can be set independently; other bit widths must be set identically to each other.

- `VK_SHADER_FLOAT_CONTROLS_INDEPENDENCE_ALL` specifies that shader float controls for all bit widths can be set independently.

- `VK_SHADER_FLOAT_CONTROLS_INDEPENDENCE_NONE` specifies that shader float controls for all bit widths must be set identically.

The `VkPhysicalDeviceDiscardRectanglePropertiesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceDiscardRectanglePropertiesEXT {
        VkStructureType    sType;
        void*              pNext;
        uint32_t           maxDiscardRectangles;
    } VkPhysicalDeviceDiscardRectanglePropertiesEXT;

The members of the `VkPhysicalDeviceDiscardRectanglePropertiesEXT` structure describe the following implementation-dependent limits:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `maxDiscardRectangles` is the maximum number of active discard rectangles that can be specified.

If the `VkPhysicalDeviceDiscardRectanglePropertiesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DISCARD_RECTANGLE_PROPERTIES_EXT`

The `VkPhysicalDeviceSampleLocationsPropertiesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceSampleLocationsPropertiesEXT {
        VkStructureType       sType;
        void*                 pNext;
        VkSampleCountFlags    sampleLocationSampleCounts;
        VkExtent2D            maxSampleLocationGridSize;
        float                 sampleLocationCoordinateRange[2];
        uint32_t              sampleLocationSubPixelBits;
        VkBool32              variableSampleLocations;
    } VkPhysicalDeviceSampleLocationsPropertiesEXT;

The members of the `VkPhysicalDeviceSampleLocationsPropertiesEXT` structure describe the following implementation-dependent limits:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `sampleLocationSampleCounts` is a bitmask of VkSampleCountFlagBits indicating the sample counts supporting custom sample locations.

- `maxSampleLocationGridSize` is the maximum size of the pixel grid in which sample locations can vary that is supported for all sample counts in `sampleLocationSampleCounts`.

- `sampleLocationCoordinateRange`[2] is the range of supported sample location coordinates.

- `sampleLocationSubPixelBits` is the number of bits of subpixel precision for sample locations.

- `variableSampleLocations` specifies whether the sample locations used by all pipelines that will be bound to a command buffer during a subpass must match. If set to `VK_TRUE`, the implementation supports variable sample locations in a subpass. If set to `VK_FALSE`, then the sample locations must stay constant in each subpass.

If the `VkPhysicalDeviceSampleLocationsPropertiesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SAMPLE_LOCATIONS_PROPERTIES_EXT`

The `VkPhysicalDeviceExternalMemoryHostPropertiesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceExternalMemoryHostPropertiesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkDeviceSize       minImportedHostPointerAlignment;
    } VkPhysicalDeviceExternalMemoryHostPropertiesEXT;

The members of the `VkPhysicalDeviceExternalMemoryHostPropertiesEXT` structure describe the following implementation-dependent limits:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `minImportedHostPointerAlignment` is the minimum required alignment, in bytes, for the base address and size of host pointers that can be imported to a Vulkan memory object.

If the `VkPhysicalDeviceExternalMemoryHostPropertiesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_MEMORY_HOST_PROPERTIES_EXT`

The `VkPhysicalDeviceMultiviewPerViewAttributesPropertiesNVX` structure is defined as:

    typedef struct VkPhysicalDeviceMultiviewPerViewAttributesPropertiesNVX {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           perViewPositionAllComponents;
    } VkPhysicalDeviceMultiviewPerViewAttributesPropertiesNVX;

The members of the `VkPhysicalDeviceMultiviewPerViewAttributesPropertiesNVX` structure describe the following implementation-dependent limits:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `perViewPositionAllComponents` is `VK_TRUE` if the implementation supports per-view position values that differ in components other than the X component.

If the `VkPhysicalDeviceMultiviewPerViewAttributesPropertiesNVX` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_PER_VIEW_ATTRIBUTES_PROPERTIES_NVX`

The `VkPhysicalDevicePointClippingProperties` structure is defined as:

    typedef struct VkPhysicalDevicePointClippingProperties {
        VkStructureType            sType;
        void*                      pNext;
        VkPointClippingBehavior    pointClippingBehavior;
    } VkPhysicalDevicePointClippingProperties;

or the equivalent

    typedef VkPhysicalDevicePointClippingProperties VkPhysicalDevicePointClippingPropertiesKHR;

The members of the `VkPhysicalDevicePointClippingProperties` structure describe the following implementation-dependent limit:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `pointClippingBehavior` is a VkPointClippingBehavior value specifying the point clipping behavior supported by the implementation.

If the `VkPhysicalDevicePointClippingProperties` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_POINT_CLIPPING_PROPERTIES`

The `VkPhysicalDeviceSubgroupProperties` structure is defined as:

    typedef struct VkPhysicalDeviceSubgroupProperties {
        VkStructureType           sType;
        void*                     pNext;
        uint32_t                  subgroupSize;
        VkShaderStageFlags        supportedStages;
        VkSubgroupFeatureFlags    supportedOperations;
        VkBool32                  quadOperationsInAllStages;
    } VkPhysicalDeviceSubgroupProperties;

The members of the `VkPhysicalDeviceSubgroupProperties` structure describe the following implementation-dependent limits:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `subgroupSize` is the default number of invocations in each subgroup. `subgroupSize` is at least 1 if any of the physical device’s queues support `VK_QUEUE_GRAPHICS_BIT` or `VK_QUEUE_COMPUTE_BIT`. `subgroupSize` is a power-of-two.

- `supportedStages` is a bitfield of VkShaderStageFlagBits describing the shader stages that group operations with subgroup scope are supported in. `supportedStages` will have the `VK_SHADER_STAGE_COMPUTE_BIT` bit set if any of the physical device’s queues support `VK_QUEUE_COMPUTE_BIT`.

- `supportedOperations` is a bitmask of VkSubgroupFeatureFlagBits specifying the sets of group operations with subgroup scope supported on this device. `supportedOperations` will have the `VK_SUBGROUP_FEATURE_BASIC_BIT` bit set if any of the physical device’s queues support `VK_QUEUE_GRAPHICS_BIT` or `VK_QUEUE_COMPUTE_BIT`.

- `quadOperationsInAllStages` is a boolean specifying whether quad group operations are available in all stages, or are restricted to fragment and compute stages.

If the `VkPhysicalDeviceSubgroupProperties` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

If `supportedOperations` includes `VK_SUBGROUP_FEATURE_QUAD_BIT`, `subgroupSize` must be greater than or equal to 4.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SUBGROUP_PROPERTIES`

Bits which can be set in VkPhysicalDeviceSubgroupProperties::`supportedOperations` and VkPhysicalDeviceVulkan11Properties::`subgroupSupportedOperations` to specify supported group operations with subgroup scope are:

    typedef enum VkSubgroupFeatureFlagBits {
        VK_SUBGROUP_FEATURE_BASIC_BIT = 0x00000001,
        VK_SUBGROUP_FEATURE_VOTE_BIT = 0x00000002,
        VK_SUBGROUP_FEATURE_ARITHMETIC_BIT = 0x00000004,
        VK_SUBGROUP_FEATURE_BALLOT_BIT = 0x00000008,
        VK_SUBGROUP_FEATURE_SHUFFLE_BIT = 0x00000010,
        VK_SUBGROUP_FEATURE_SHUFFLE_RELATIVE_BIT = 0x00000020,
        VK_SUBGROUP_FEATURE_CLUSTERED_BIT = 0x00000040,
        VK_SUBGROUP_FEATURE_QUAD_BIT = 0x00000080,
        VK_SUBGROUP_FEATURE_PARTITIONED_BIT_NV = 0x00000100,
        VK_SUBGROUP_FEATURE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkSubgroupFeatureFlagBits;

- `VK_SUBGROUP_FEATURE_BASIC_BIT` specifies the device will accept SPIR-V shader modules containing the `GroupNonUniform` capability.

- `VK_SUBGROUP_FEATURE_VOTE_BIT` specifies the device will accept SPIR-V shader modules containing the `GroupNonUniformVote` capability.

- `VK_SUBGROUP_FEATURE_ARITHMETIC_BIT` specifies the device will accept SPIR-V shader modules containing the `GroupNonUniformArithmetic` capability.

- `VK_SUBGROUP_FEATURE_BALLOT_BIT` specifies the device will accept SPIR-V shader modules containing the `GroupNonUniformBallot` capability.

- `VK_SUBGROUP_FEATURE_SHUFFLE_BIT` specifies the device will accept SPIR-V shader modules containing the `GroupNonUniformShuffle` capability.

- `VK_SUBGROUP_FEATURE_SHUFFLE_RELATIVE_BIT` specifies the device will accept SPIR-V shader modules containing the `GroupNonUniformShuffleRelative` capability.

- `VK_SUBGROUP_FEATURE_CLUSTERED_BIT` specifies the device will accept SPIR-V shader modules containing the `GroupNonUniformClustered` capability.

- `VK_SUBGROUP_FEATURE_QUAD_BIT` specifies the device will accept SPIR-V shader modules containing the `GroupNonUniformQuad` capability.

- `VK_SUBGROUP_FEATURE_PARTITIONED_BIT_NV` specifies the device will accept SPIR-V shader modules containing the `GroupNonUniformPartitionedNV` capability.

    typedef VkFlags VkSubgroupFeatureFlags;

`VkSubgroupFeatureFlags` is a bitmask type for setting a mask of zero or more VkSubgroupFeatureFlagBits.

The `VkPhysicalDeviceSubgroupSizeControlPropertiesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceSubgroupSizeControlPropertiesEXT {
        VkStructureType       sType;
        void*                 pNext;
        uint32_t              minSubgroupSize;
        uint32_t              maxSubgroupSize;
        uint32_t              maxComputeWorkgroupSubgroups;
        VkShaderStageFlags    requiredSubgroupSizeStages;
    } VkPhysicalDeviceSubgroupSizeControlPropertiesEXT;

The members of the `VkPhysicalDeviceSubgroupSizeControlPropertiesEXT` structure describe the following properties:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `minSubgroupSize` is the minimum subgroup size supported by this device. `minSubgroupSize` is at least one if any of the physical device’s queues support `VK_QUEUE_GRAPHICS_BIT` or `VK_QUEUE_COMPUTE_BIT`. `minSubgroupSize` is a power-of-two. `minSubgroupSize` is less than or equal to `maxSubgroupSize`. `minSubgroupSize` is less than or equal to subgroupSize.

- `maxSubgroupSize` is the maximum subgroup size supported by this device. `maxSubgroupSize` is at least one if any of the physical device’s queues support `VK_QUEUE_GRAPHICS_BIT` or `VK_QUEUE_COMPUTE_BIT`. `maxSubgroupSize` is a power-of-two. `maxSubgroupSize` is greater than or equal to `minSubgroupSize`. `maxSubgroupSize` is greater than or equal to subgroupSize.

- `maxComputeWorkgroupSubgroups` is the maximum number of subgroups supported by the implementation within a workgroup.

- `requiredSubgroupSizeStages` is a bitfield of what shader stages support having a required subgroup size specified.

If the `VkPhysicalDeviceSubgroupSizeControlPropertiesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

If VkPhysicalDeviceSubgroupProperties::`supportedOperations` includes `VK_SUBGROUP_FEATURE_QUAD_BIT`, `minSubgroupSize` must be greater than or equal to 4.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SUBGROUP_SIZE_CONTROL_PROPERTIES_EXT`

The `VkPhysicalDeviceBlendOperationAdvancedPropertiesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceBlendOperationAdvancedPropertiesEXT {
        VkStructureType    sType;
        void*              pNext;
        uint32_t           advancedBlendMaxColorAttachments;
        VkBool32           advancedBlendIndependentBlend;
        VkBool32           advancedBlendNonPremultipliedSrcColor;
        VkBool32           advancedBlendNonPremultipliedDstColor;
        VkBool32           advancedBlendCorrelatedOverlap;
        VkBool32           advancedBlendAllOperations;
    } VkPhysicalDeviceBlendOperationAdvancedPropertiesEXT;

The members of the `VkPhysicalDeviceBlendOperationAdvancedPropertiesEXT` structure describe the following implementation-dependent limits:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `advancedBlendMaxColorAttachments` is one greater than the highest color attachment index that can be used in a subpass, for a pipeline that uses an advanced blend operation.

- `advancedBlendIndependentBlend` specifies whether advanced blend operations can vary per-attachment.

- `advancedBlendNonPremultipliedSrcColor` specifies whether the source color can be treated as non-premultiplied. If this is `VK_FALSE`, then VkPipelineColorBlendAdvancedStateCreateInfoEXT::`srcPremultiplied` must be `VK_TRUE`.

- `advancedBlendNonPremultipliedDstColor` specifies whether the destination color can be treated as non-premultiplied. If this is `VK_FALSE`, then VkPipelineColorBlendAdvancedStateCreateInfoEXT::`dstPremultiplied` must be `VK_TRUE`.

- `advancedBlendCorrelatedOverlap` specifies whether the overlap mode can be treated as correlated. If this is `VK_FALSE`, then VkPipelineColorBlendAdvancedStateCreateInfoEXT::`blendOverlap` must be `VK_BLEND_OVERLAP_UNCORRELATED_EXT`.

- `advancedBlendAllOperations` specifies whether all advanced blend operation enums are supported. See the valid usage of VkPipelineColorBlendAttachmentState.

If the `VkPhysicalDeviceBlendOperationAdvancedPropertiesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_BLEND_OPERATION_ADVANCED_PROPERTIES_EXT`

The `VkPhysicalDeviceVertexAttributeDivisorPropertiesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceVertexAttributeDivisorPropertiesEXT {
        VkStructureType    sType;
        void*              pNext;
        uint32_t           maxVertexAttribDivisor;
    } VkPhysicalDeviceVertexAttributeDivisorPropertiesEXT;

The members of the `VkPhysicalDeviceVertexAttributeDivisorPropertiesEXT` structure describe the following implementation-dependent limits:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `maxVertexAttribDivisor` is the maximum value of the number of instances that will repeat the value of vertex attribute data when instanced rendering is enabled.

If the `VkPhysicalDeviceVertexAttributeDivisorPropertiesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VERTEX_ATTRIBUTE_DIVISOR_PROPERTIES_EXT`

The `VkPhysicalDeviceSamplerFilterMinmaxProperties` structure is defined as:

    typedef struct VkPhysicalDeviceSamplerFilterMinmaxProperties {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           filterMinmaxSingleComponentFormats;
        VkBool32           filterMinmaxImageComponentMapping;
    } VkPhysicalDeviceSamplerFilterMinmaxProperties;

or the equivalent

    typedef VkPhysicalDeviceSamplerFilterMinmaxProperties VkPhysicalDeviceSamplerFilterMinmaxPropertiesEXT;

The members of the `VkPhysicalDeviceSamplerFilterMinmaxProperties` structure describe the following implementation-dependent limits:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `filterMinmaxSingleComponentFormats` is a boolean value indicating whether a minimum set of required formats support min/max filtering.

- `filterMinmaxImageComponentMapping` is a boolean value indicating whether the implementation supports non-identity component mapping of the image when doing min/max filtering.

If the `VkPhysicalDeviceSamplerFilterMinmaxProperties` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

If `filterMinmaxSingleComponentFormats` is `VK_TRUE`, the following formats must support the `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_MINMAX_BIT` feature with `VK_IMAGE_TILING_OPTIMAL`, if they support `VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT`.

- `VK_FORMAT_R8_UNORM`

- `VK_FORMAT_R8_SNORM`

- `VK_FORMAT_R16_UNORM`

- `VK_FORMAT_R16_SNORM`

- `VK_FORMAT_R16_SFLOAT`

- `VK_FORMAT_R32_SFLOAT`

- `VK_FORMAT_D16_UNORM`

- `VK_FORMAT_X8_D24_UNORM_PACK32`

- `VK_FORMAT_D32_SFLOAT`

- `VK_FORMAT_D16_UNORM_S8_UINT`

- `VK_FORMAT_D24_UNORM_S8_UINT`

- `VK_FORMAT_D32_SFLOAT_S8_UINT`

If the format is a depth/stencil format, this bit only specifies that the depth aspect (not the stencil aspect) of an image of this format supports min/max filtering, and that min/max filtering of the depth aspect is supported when depth compare is disabled in the sampler.

If `filterMinmaxImageComponentMapping` is `VK_FALSE` the component mapping of the image view used with min/max filtering must have been created with the `r` component set to `VK_COMPONENT_SWIZZLE_IDENTITY`. Only the `r` component of the sampled image value is defined and the other component values are undefined. If `filterMinmaxImageComponentMapping` is `VK_TRUE` this restriction does not apply and image component mapping works as normal.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SAMPLER_FILTER_MINMAX_PROPERTIES`

The `VkPhysicalDeviceProtectedMemoryProperties` structure is defined as:

    typedef struct VkPhysicalDeviceProtectedMemoryProperties {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           protectedNoFault;
    } VkPhysicalDeviceProtectedMemoryProperties;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `protectedNoFault` specifies the behavior of the implementation when protected memory access rules are broken. If `protectedNoFault` is `VK_TRUE`, breaking those rules will not result in process termination or device loss.

If the `VkPhysicalDeviceProtectedMemoryProperties` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with a value indicating the implementation-dependent behavior.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROTECTED_MEMORY_PROPERTIES`

The `VkPhysicalDeviceMaintenance3Properties` structure is defined as:

    typedef struct VkPhysicalDeviceMaintenance3Properties {
        VkStructureType    sType;
        void*              pNext;
        uint32_t           maxPerSetDescriptors;
        VkDeviceSize       maxMemoryAllocationSize;
    } VkPhysicalDeviceMaintenance3Properties;

or the equivalent

    typedef VkPhysicalDeviceMaintenance3Properties VkPhysicalDeviceMaintenance3PropertiesKHR;

The members of the `VkPhysicalDeviceMaintenance3Properties` structure describe the following implementation-dependent limits:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `maxPerSetDescriptors` is a maximum number of descriptors (summed over all descriptor types) in a single descriptor set that is guaranteed to satisfy any implementation-dependent constraints on the size of a descriptor set itself. Applications can query whether a descriptor set that goes beyond this limit is supported using vkGetDescriptorSetLayoutSupport.

- `maxMemoryAllocationSize` is the maximum size of a memory allocation that can be created, even if there is more space available in the heap.

If the `VkPhysicalDeviceMaintenance3Properties` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MAINTENANCE_3_PROPERTIES`

The `VkPhysicalDeviceMeshShaderPropertiesNV` structure is defined as:

    typedef struct VkPhysicalDeviceMeshShaderPropertiesNV {
        VkStructureType    sType;
        void*              pNext;
        uint32_t           maxDrawMeshTasksCount;
        uint32_t           maxTaskWorkGroupInvocations;
        uint32_t           maxTaskWorkGroupSize[3];
        uint32_t           maxTaskTotalMemorySize;
        uint32_t           maxTaskOutputCount;
        uint32_t           maxMeshWorkGroupInvocations;
        uint32_t           maxMeshWorkGroupSize[3];
        uint32_t           maxMeshTotalMemorySize;
        uint32_t           maxMeshOutputVertices;
        uint32_t           maxMeshOutputPrimitives;
        uint32_t           maxMeshMultiviewViewCount;
        uint32_t           meshOutputPerVertexGranularity;
        uint32_t           meshOutputPerPrimitiveGranularity;
    } VkPhysicalDeviceMeshShaderPropertiesNV;

The members of the `VkPhysicalDeviceMeshShaderPropertiesNV` structure describe the following implementation-dependent limits:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `maxDrawMeshTasksCount` is the maximum number of local workgroups that can be launched by a single draw mesh tasks command. See Programmable Mesh Shading.

- `maxTaskWorkGroupInvocations` is the maximum total number of task shader invocations in a single local workgroup. The product of the X, Y, and Z sizes, as specified by the `LocalSize` execution mode in shader modules or by the object decorated by the `WorkgroupSize` decoration, must be less than or equal to this limit.

- `maxTaskWorkGroupSize`[3] is the maximum size of a local task workgroup. These three values represent the maximum local workgroup size in the X, Y, and Z dimensions, respectively. The `x`, `y`, and `z` sizes, as specified by the `LocalSize` execution mode or by the object decorated by the `WorkgroupSize` decoration in shader modules, must be less than or equal to the corresponding limit.

- `maxTaskTotalMemorySize` is the maximum number of bytes that the task shader can use in total for shared and output memory combined.

- `maxTaskOutputCount` is the maximum number of output tasks a single task shader workgroup can emit.

- `maxMeshWorkGroupInvocations` is the maximum total number of mesh shader invocations in a single local workgroup. The product of the X, Y, and Z sizes, as specified by the `LocalSize` execution mode in shader modules or by the object decorated by the `WorkgroupSize` decoration, must be less than or equal to this limit.

- `maxMeshWorkGroupSize`[3] is the maximum size of a local mesh workgroup. These three values represent the maximum local workgroup size in the X, Y, and Z dimensions, respectively. The `x`, `y`, and `z` sizes, as specified by the `LocalSize` execution mode or by the object decorated by the `WorkgroupSize` decoration in shader modules, must be less than or equal to the corresponding limit.

- `maxMeshTotalMemorySize` is the maximum number of bytes that the mesh shader can use in total for shared and output memory combined.

- `maxMeshOutputVertices` is the maximum number of vertices a mesh shader output can store.

- `maxMeshOutputPrimitives` is the maximum number of primitives a mesh shader output can store.

- `maxMeshMultiviewViewCount` is the maximum number of multi-view views a mesh shader can use.

- `meshOutputPerVertexGranularity` is the granularity with which mesh vertex outputs are allocated. The value can be used to compute the memory size used by the mesh shader, which must be less than or equal to `maxMeshTotalMemorySize`.

- `meshOutputPerPrimitiveGranularity` is the granularity with which mesh outputs qualified as per-primitive are allocated. The value can be used to compute the memory size used by the mesh shader, which must be less than or equal to `maxMeshTotalMemorySize`.

If the `VkPhysicalDeviceMeshShaderPropertiesNV` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MESH_SHADER_PROPERTIES_NV`

The `VkPhysicalDeviceDescriptorIndexingProperties` structure is defined as:

    typedef struct VkPhysicalDeviceDescriptorIndexingProperties {
        VkStructureType    sType;
        void*              pNext;
        uint32_t           maxUpdateAfterBindDescriptorsInAllPools;
        VkBool32           shaderUniformBufferArrayNonUniformIndexingNative;
        VkBool32           shaderSampledImageArrayNonUniformIndexingNative;
        VkBool32           shaderStorageBufferArrayNonUniformIndexingNative;
        VkBool32           shaderStorageImageArrayNonUniformIndexingNative;
        VkBool32           shaderInputAttachmentArrayNonUniformIndexingNative;
        VkBool32           robustBufferAccessUpdateAfterBind;
        VkBool32           quadDivergentImplicitLod;
        uint32_t           maxPerStageDescriptorUpdateAfterBindSamplers;
        uint32_t           maxPerStageDescriptorUpdateAfterBindUniformBuffers;
        uint32_t           maxPerStageDescriptorUpdateAfterBindStorageBuffers;
        uint32_t           maxPerStageDescriptorUpdateAfterBindSampledImages;
        uint32_t           maxPerStageDescriptorUpdateAfterBindStorageImages;
        uint32_t           maxPerStageDescriptorUpdateAfterBindInputAttachments;
        uint32_t           maxPerStageUpdateAfterBindResources;
        uint32_t           maxDescriptorSetUpdateAfterBindSamplers;
        uint32_t           maxDescriptorSetUpdateAfterBindUniformBuffers;
        uint32_t           maxDescriptorSetUpdateAfterBindUniformBuffersDynamic;
        uint32_t           maxDescriptorSetUpdateAfterBindStorageBuffers;
        uint32_t           maxDescriptorSetUpdateAfterBindStorageBuffersDynamic;
        uint32_t           maxDescriptorSetUpdateAfterBindSampledImages;
        uint32_t           maxDescriptorSetUpdateAfterBindStorageImages;
        uint32_t           maxDescriptorSetUpdateAfterBindInputAttachments;
    } VkPhysicalDeviceDescriptorIndexingProperties;

or the equivalent

    typedef VkPhysicalDeviceDescriptorIndexingProperties VkPhysicalDeviceDescriptorIndexingPropertiesEXT;

The members of the `VkPhysicalDeviceDescriptorIndexingProperties` structure describe the following implementation-dependent limits:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `maxUpdateAfterBindDescriptorsInAllPools` is the maximum number of descriptors (summed over all descriptor types) that can be created across all pools that are created with the `VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT` bit set. Pool creation may fail when this limit is exceeded, or when the space this limit represents is unable to satisfy a pool creation due to fragmentation.

- `shaderUniformBufferArrayNonUniformIndexingNative` is a boolean value indicating whether uniform buffer descriptors natively support nonuniform indexing. If this is `VK_FALSE`, then a single dynamic instance of an instruction that nonuniformly indexes an array of uniform buffers may execute multiple times in order to access all the descriptors.

- `shaderSampledImageArrayNonUniformIndexingNative` is a boolean value indicating whether sampler and image descriptors natively support nonuniform indexing. If this is `VK_FALSE`, then a single dynamic instance of an instruction that nonuniformly indexes an array of samplers or images may execute multiple times in order to access all the descriptors.

- `shaderStorageBufferArrayNonUniformIndexingNative` is a boolean value indicating whether storage buffer descriptors natively support nonuniform indexing. If this is `VK_FALSE`, then a single dynamic instance of an instruction that nonuniformly indexes an array of storage buffers may execute multiple times in order to access all the descriptors.

- `shaderStorageImageArrayNonUniformIndexingNative` is a boolean value indicating whether storage image descriptors natively support nonuniform indexing. If this is `VK_FALSE`, then a single dynamic instance of an instruction that nonuniformly indexes an array of storage images may execute multiple times in order to access all the descriptors.

- `shaderInputAttachmentArrayNonUniformIndexingNative` is a boolean value indicating whether input attachment descriptors natively support nonuniform indexing. If this is `VK_FALSE`, then a single dynamic instance of an instruction that nonuniformly indexes an array of input attachments may execute multiple times in order to access all the descriptors.

- `robustBufferAccessUpdateAfterBind` is a boolean value indicating whether `robustBufferAccess` can be enabled in a device simultaneously with `descriptorBindingUniformBufferUpdateAfterBind`, `descriptorBindingStorageBufferUpdateAfterBind`, `descriptorBindingUniformTexelBufferUpdateAfterBind`, and/or `descriptorBindingStorageTexelBufferUpdateAfterBind`. If this is `VK_FALSE`, then either `robustBufferAccess` must be disabled or all of these update-after-bind features must be disabled.

- `quadDivergentImplicitLod` is a boolean value indicating whether implicit level of detail calculations for image operations have well-defined results when the image and/or sampler objects used for the instruction are not uniform within a quad. See Derivative Image Operations.

- `maxPerStageDescriptorUpdateAfterBindSamplers` is similar to `maxPerStageDescriptorSamplers` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxPerStageDescriptorUpdateAfterBindUniformBuffers` is similar to `maxPerStageDescriptorUniformBuffers` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxPerStageDescriptorUpdateAfterBindStorageBuffers` is similar to `maxPerStageDescriptorStorageBuffers` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxPerStageDescriptorUpdateAfterBindSampledImages` is similar to `maxPerStageDescriptorSampledImages` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxPerStageDescriptorUpdateAfterBindStorageImages` is similar to `maxPerStageDescriptorStorageImages` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxPerStageDescriptorUpdateAfterBindInputAttachments` is similar to `maxPerStageDescriptorInputAttachments` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxPerStageUpdateAfterBindResources` is similar to `maxPerStageResources` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxDescriptorSetUpdateAfterBindSamplers` is similar to `maxDescriptorSetSamplers` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxDescriptorSetUpdateAfterBindUniformBuffers` is similar to `maxDescriptorSetUniformBuffers` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxDescriptorSetUpdateAfterBindUniformBuffersDynamic` is similar to `maxDescriptorSetUniformBuffersDynamic` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxDescriptorSetUpdateAfterBindStorageBuffers` is similar to `maxDescriptorSetStorageBuffers` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxDescriptorSetUpdateAfterBindStorageBuffersDynamic` is similar to `maxDescriptorSetStorageBuffersDynamic` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxDescriptorSetUpdateAfterBindSampledImages` is similar to `maxDescriptorSetSampledImages` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxDescriptorSetUpdateAfterBindStorageImages` is similar to `maxDescriptorSetStorageImages` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxDescriptorSetUpdateAfterBindInputAttachments` is similar to `maxDescriptorSetInputAttachments` but counts descriptors from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

If the `VkPhysicalDeviceDescriptorIndexingProperties` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_PROPERTIES`

The `VkPhysicalDeviceInlineUniformBlockPropertiesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceInlineUniformBlockPropertiesEXT {
        VkStructureType    sType;
        void*              pNext;
        uint32_t           maxInlineUniformBlockSize;
        uint32_t           maxPerStageDescriptorInlineUniformBlocks;
        uint32_t           maxPerStageDescriptorUpdateAfterBindInlineUniformBlocks;
        uint32_t           maxDescriptorSetInlineUniformBlocks;
        uint32_t           maxDescriptorSetUpdateAfterBindInlineUniformBlocks;
    } VkPhysicalDeviceInlineUniformBlockPropertiesEXT;

The members of the `VkPhysicalDeviceInlineUniformBlockPropertiesEXT` structure describe the following implementation-dependent limits:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `maxInlineUniformBlockSize` is the maximum size in bytes of an inline uniform block binding.

- `maxPerStageDescriptorInlineUniformBlock` is the maximum number of inline uniform block bindings that can be accessible to a single shader stage in a pipeline layout. Descriptor bindings with a descriptor type of `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` count against this limit. Only descriptor bindings in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set count against this limit.

- `maxPerStageDescriptorUpdateAfterBindInlineUniformBlocks` is similar to `maxPerStageDescriptorInlineUniformBlocks` but counts descriptor bindings from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

- `maxDescriptorSetInlineUniformBlocks` is the maximum number of inline uniform block bindings that can be included in descriptor bindings in a pipeline layout across all pipeline shader stages and descriptor set numbers. Descriptor bindings with a descriptor type of `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT` count against this limit. Only descriptor bindings in descriptor set layouts created without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set count against this limit.

- `maxDescriptorSetUpdateAfterBindInlineUniformBlocks` is similar to `maxDescriptorSetInlineUniformBlocks` but counts descriptor bindings from descriptor sets created with or without the `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT` bit set.

If the `VkPhysicalDeviceInlineUniformBlockPropertiesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_INLINE_UNIFORM_BLOCK_PROPERTIES_EXT`

The `VkPhysicalDeviceConservativeRasterizationPropertiesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceConservativeRasterizationPropertiesEXT {
        VkStructureType    sType;
        void*              pNext;
        float              primitiveOverestimationSize;
        float              maxExtraPrimitiveOverestimationSize;
        float              extraPrimitiveOverestimationSizeGranularity;
        VkBool32           primitiveUnderestimation;
        VkBool32           conservativePointAndLineRasterization;
        VkBool32           degenerateTrianglesRasterized;
        VkBool32           degenerateLinesRasterized;
        VkBool32           fullyCoveredFragmentShaderInputVariable;
        VkBool32           conservativeRasterizationPostDepthCoverage;
    } VkPhysicalDeviceConservativeRasterizationPropertiesEXT;

The members of the `VkPhysicalDeviceConservativeRasterizationPropertiesEXT` structure describe the following implementation-dependent limits:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `primitiveOverestimationSize` is the size in pixels the generating primitive is increased at each of its edges during conservative rasterization overestimation mode. Even with a size of 0.0, conservative rasterization overestimation rules still apply and if any part of the pixel rectangle is covered by the generating primitive, fragments are generated for the entire pixel. However implementations may make the pixel coverage area even more conservative by increasing the size of the generating primitive.

- `maxExtraPrimitiveOverestimationSize` is the maximum size in pixels of extra overestimation the implementation supports in the pipeline state. A value of 0.0 means the implementation does not support any additional overestimation of the generating primitive during conservative rasterization. A value above 0.0 allows the application to further increase the size of the generating primitive during conservative rasterization overestimation.

- `extraPrimitiveOverestimationSizeGranularity` is the granularity of extra overestimation that can be specified in the pipeline state between 0.0 and `maxExtraPrimitiveOverestimationSize` inclusive. A value of 0.0 means the implementation can use the smallest representable non-zero value in the screen space pixel fixed-point grid.

- `primitiveUnderestimation` is true if the implementation supports the `VK_CONSERVATIVE_RASTERIZATION_MODE_UNDERESTIMATE_EXT` conservative rasterization mode in addition to `VK_CONSERVATIVE_RASTERIZATION_MODE_OVERESTIMATE_EXT`. Otherwise the implementation only supports `VK_CONSERVATIVE_RASTERIZATION_MODE_OVERESTIMATE_EXT`.

- `conservativePointAndLineRasterization` is true if the implementation supports conservative rasterization of point and line primitives as well as triangle primitives. Otherwise the implementation only supports triangle primitives.

- `degenerateTrianglesRasterized` is false if the implementation culls primitives generated from triangles that become zero area after they are quantized to the fixed-point rasterization pixel grid. `degenerateTrianglesRasterized` is true if these primitives are not culled and the provoking vertex attributes and depth value are used for the fragments. The primitive area calculation is done on the primitive generated from the clipped triangle if applicable. Zero area primitives are backfacing and the application can enable backface culling if desired.

- `degenerateLinesRasterized` is false if the implementation culls lines that become zero length after they are quantized to the fixed-point rasterization pixel grid. `degenerateLinesRasterized` is true if zero length lines are not culled and the provoking vertex attributes and depth value are used for the fragments.

- `fullyCoveredFragmentShaderInputVariable` is true if the implementation supports the SPIR-V builtin fragment shader input variable `FullyCoveredEXT` which specifies that conservative rasterization is enabled and the fragment area is fully covered by the generating primitive.

- `conservativeRasterizationPostDepthCoverage` is true if the implementation supports conservative rasterization with the `PostDepthCoverage` execution mode enabled. When supported the `SampleMask` built-in input variable will reflect the coverage after the early per-fragment depth and stencil tests are applied even when conservative rasterization is enabled. Otherwise `PostDepthCoverage` execution mode must not be used when conservative rasterization is enabled.

If the `VkPhysicalDeviceConservativeRasterizationPropertiesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits and properties.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_CONSERVATIVE_RASTERIZATION_PROPERTIES_EXT`

The `VkPhysicalDeviceFragmentDensityMapPropertiesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceFragmentDensityMapPropertiesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkExtent2D         minFragmentDensityTexelSize;
        VkExtent2D         maxFragmentDensityTexelSize;
        VkBool32           fragmentDensityInvocations;
    } VkPhysicalDeviceFragmentDensityMapPropertiesEXT;

The members of the `VkPhysicalDeviceFragmentDensityMapPropertiesEXT` structure describe the following implementation-dependent limits:

- `minFragmentDensityTexelSize` is the minimum fragment density texel size.

- `maxFragmentDensityTexelSize` is the maximum fragment density texel size.

- `fragmentDensityInvocations` specifies whether the implementation may invoke additional fragment shader invocations for each covered sample.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FRAGMENT_DENSITY_MAP_PROPERTIES_EXT`

If the `VkPhysicalDeviceFragmentDensityMapPropertiesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits and properties.

The `VkPhysicalDeviceShaderCorePropertiesAMD` structure is defined as:

    typedef struct VkPhysicalDeviceShaderCorePropertiesAMD {
        VkStructureType    sType;
        void*              pNext;
        uint32_t           shaderEngineCount;
        uint32_t           shaderArraysPerEngineCount;
        uint32_t           computeUnitsPerShaderArray;
        uint32_t           simdPerComputeUnit;
        uint32_t           wavefrontsPerSimd;
        uint32_t           wavefrontSize;
        uint32_t           sgprsPerSimd;
        uint32_t           minSgprAllocation;
        uint32_t           maxSgprAllocation;
        uint32_t           sgprAllocationGranularity;
        uint32_t           vgprsPerSimd;
        uint32_t           minVgprAllocation;
        uint32_t           maxVgprAllocation;
        uint32_t           vgprAllocationGranularity;
    } VkPhysicalDeviceShaderCorePropertiesAMD;

The members of the `VkPhysicalDeviceShaderCorePropertiesAMD` structure describe the following implementation-dependent limits:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `shaderEngineCount` is an unsigned integer value indicating the number of shader engines found inside the shader core of the physical device.

- `shaderArraysPerEngineCount` is an unsigned integer value indicating the number of shader arrays inside a shader engine. Each shader array has its own scan converter, set of compute units, and a render back end (color and depth buffers). Shader arrays within a shader engine share shader processor input (wave launcher) and shader export (export buffer) units. Currently, a shader engine can have one or two shader arrays.

- `computeUnitsPerShaderArray` is an unsigned integer value indicating the physical number of compute units within a shader array. The active number of compute units in a shader array may be lower. A compute unit houses a set of SIMDs along with a sequencer module and a local data store.

- `simdPerComputeUnit` is an unsigned integer value indicating the number of SIMDs inside a compute unit. Each SIMD processes a single instruction at a time.

- `wavefrontSize` is an unsigned integer value indicating the maximum size of a subgroup.

- `sgprsPerSimd` is an unsigned integer value indicating the number of physical Scalar General Purpose Registers (SGPRs) per SIMD.

- `minSgprAllocation` is an unsigned integer value indicating the minimum number of SGPRs allocated for a wave.

- `maxSgprAllocation` is an unsigned integer value indicating the maximum number of SGPRs allocated for a wave.

- `sgprAllocationGranularity` is an unsigned integer value indicating the granularity of SGPR allocation for a wave.

- `vgprsPerSimd` is an unsigned integer value indicating the number of physical Vector General Purpose Registers (VGPRs) per SIMD.

- `minVgprAllocation` is an unsigned integer value indicating the minimum number of VGPRs allocated for a wave.

- `maxVgprAllocation` is an unsigned integer value indicating the maximum number of VGPRs allocated for a wave.

- `vgprAllocationGranularity` is an unsigned integer value indicating the granularity of VGPR allocation for a wave.

If the `VkPhysicalDeviceShaderCorePropertiesAMD` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_CORE_PROPERTIES_AMD`

The `VkPhysicalDeviceShaderCoreProperties2AMD` structure is defined as:

    typedef struct VkPhysicalDeviceShaderCoreProperties2AMD {
        VkStructureType                   sType;
        void*                             pNext;
        VkShaderCorePropertiesFlagsAMD    shaderCoreFeatures;
        uint32_t                          activeComputeUnitCount;
    } VkPhysicalDeviceShaderCoreProperties2AMD;

The members of the `VkPhysicalDeviceShaderCoreProperties2AMD` structure describe the following implementation-dependent limits:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `shaderCoreFeatures` is a bitmask of VkShaderCorePropertiesFlagBitsAMD indicating the set of features supported by the shader core.

- `activeComputeUnitCount` is an unsigned integer value indicating the number of compute units that have been enabled.

If the `VkPhysicalDeviceShaderCoreProperties2AMD` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_CORE_PROPERTIES_2_AMD`

Bits for this type may be defined by future extensions, or new versions of the `VK_AMD_shader_core_properties2` extension. Possible values of the `flags` member of VkShaderCorePropertiesFlagsAMD are:

    typedef enum VkShaderCorePropertiesFlagBitsAMD {
        VK_SHADER_CORE_PROPERTIES_FLAG_BITS_MAX_ENUM_AMD = 0x7FFFFFFF
    } VkShaderCorePropertiesFlagBitsAMD;

    typedef VkFlags VkShaderCorePropertiesFlagsAMD;

`VkShaderCorePropertiesFlagsAMD` is a bitmask type for providing zero or more VkShaderCorePropertiesFlagBitsAMD.

The `VkPhysicalDeviceDepthStencilResolveProperties` structure is defined as:

    typedef struct VkPhysicalDeviceDepthStencilResolveProperties {
        VkStructureType       sType;
        void*                 pNext;
        VkResolveModeFlags    supportedDepthResolveModes;
        VkResolveModeFlags    supportedStencilResolveModes;
        VkBool32              independentResolveNone;
        VkBool32              independentResolve;
    } VkPhysicalDeviceDepthStencilResolveProperties;

or the equivalent

    typedef VkPhysicalDeviceDepthStencilResolveProperties VkPhysicalDeviceDepthStencilResolvePropertiesKHR;

The members of the `VkPhysicalDeviceDepthStencilResolveProperties` structure describe the following implementation-dependent limits:

- `supportedDepthResolveModes` is a bitmask of VkResolveModeFlagBits indicating the set of supported depth resolve modes. `VK_RESOLVE_MODE_SAMPLE_ZERO_BIT` must be included in the set but implementations may support additional modes.

- `supportedStencilResolveModes` is a bitmask of VkResolveModeFlagBits indicating the set of supported stencil resolve modes. `VK_RESOLVE_MODE_SAMPLE_ZERO_BIT` must be included in the set but implementations may support additional modes. `VK_RESOLVE_MODE_AVERAGE_BIT` must not be included in the set.

- `independentResolveNone` is `VK_TRUE` if the implementation supports setting the depth and stencil resolve modes to different values when one of those modes is `VK_RESOLVE_MODE_NONE`. Otherwise the implementation only supports setting both modes to the same value.

- `independentResolve` is `VK_TRUE` if the implementation supports all combinations of the supported depth and stencil resolve modes, including setting either depth or stencil resolve mode to `VK_RESOLVE_MODE_NONE`. An implementation that supports `independentResolve` must also support `independentResolveNone`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DEPTH_STENCIL_RESOLVE_PROPERTIES`

The `VkPhysicalDevicePerformanceQueryFeaturesKHR` structure is defined as:

    typedef struct VkPhysicalDevicePerformanceQueryFeaturesKHR {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           performanceCounterQueryPools;
        VkBool32           performanceCounterMultipleQueryPools;
    } VkPhysicalDevicePerformanceQueryFeaturesKHR;

The members of the `VkPhysicalDevicePerformanceQueryFeaturesKHR` structure describe the following implementation-dependent features:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `performanceCounterQueryPools` is `VK_TRUE` if the physical device supports performance counter query pools.

- `performanceCounterMultipleQueryPools` is `VK_TRUE`` if the physical device supports using multiple performance query pools in a primary command buffer and secondary command buffers executed within it.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PERFORMANCE_QUERY_FEATURES_KHR`

To query supported performance counter query pool features, call vkGetPhysicalDeviceFeatures2 with a `VkPhysicalDevicePerformanceQueryFeaturesKHR` structure included in the `pNext` chain of its `pFeatures` parameter. The `VkPhysicalDevicePerformanceQueryFeaturesKHR` structure can also be included in the `pNext` chain of a VkDeviceCreateInfo structure, in which case it controls which additional features are enabled in the device.

The `VkPhysicalDevicePerformanceQueryPropertiesKHR` structure is defined as:

    typedef struct VkPhysicalDevicePerformanceQueryPropertiesKHR {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           allowCommandBufferQueryCopies;
    } VkPhysicalDevicePerformanceQueryPropertiesKHR;

The members of the `VkPhysicalDevicePerformanceQueryPropertiesKHR` structure describe the following implementation-dependent properties:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `allowCommandBufferQueryCopies` is `VK_TRUE` if the performance query pools are allowed to be used with vkCmdCopyQueryPoolResults.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PERFORMANCE_QUERY_PROPERTIES_KHR`

If the `VkPhysicalDevicePerformanceQueryPropertiesKHR` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent properties.

The `VkPhysicalDeviceShadingRateImagePropertiesNV` structure is defined as:

    typedef struct VkPhysicalDeviceShadingRateImagePropertiesNV {
        VkStructureType    sType;
        void*              pNext;
        VkExtent2D         shadingRateTexelSize;
        uint32_t           shadingRatePaletteSize;
        uint32_t           shadingRateMaxCoarseSamples;
    } VkPhysicalDeviceShadingRateImagePropertiesNV;

The members of the `VkPhysicalDeviceShadingRateImagePropertiesNV` structure describe the following implementation-dependent properties related to the shading rate image feature:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `shadingRateTexelSize` indicates the width and height of the portion of the framebuffer corresponding to each texel in the shading rate image.

- `shadingRatePaletteSize` indicates the maximum number of palette entries supported for the shading rate image.

- `shadingRateMaxCoarseSamples` specifies the maximum number of coverage samples supported in a single fragment. If the product of the fragment size derived from the base shading rate and the number of coverage samples per pixel exceeds this limit, the final shading rate will be adjusted so that its product does not exceed the limit.

If the `VkPhysicalDeviceShadingRateImagePropertiesNV` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADING_RATE_IMAGE_PROPERTIES_NV`

The `VkPhysicalDeviceTransformFeedbackPropertiesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceTransformFeedbackPropertiesEXT {
        VkStructureType    sType;
        void*              pNext;
        uint32_t           maxTransformFeedbackStreams;
        uint32_t           maxTransformFeedbackBuffers;
        VkDeviceSize       maxTransformFeedbackBufferSize;
        uint32_t           maxTransformFeedbackStreamDataSize;
        uint32_t           maxTransformFeedbackBufferDataSize;
        uint32_t           maxTransformFeedbackBufferDataStride;
        VkBool32           transformFeedbackQueries;
        VkBool32           transformFeedbackStreamsLinesTriangles;
        VkBool32           transformFeedbackRasterizationStreamSelect;
        VkBool32           transformFeedbackDraw;
    } VkPhysicalDeviceTransformFeedbackPropertiesEXT;

The members of the `VkPhysicalDeviceTransformFeedbackPropertiesEXT` structure describe the following implementation-dependent limits:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `maxTransformFeedbackStreams` is the maximum number of vertex streams that can be output from geometry shaders declared with the `GeometryStreams` capability. If the implementation does not support `VkPhysicalDeviceTransformFeedbackFeaturesEXT`::`geometryStreams` then `maxTransformFeedbackStreams` must be set to `1`.

- `maxTransformFeedbackBuffers` is the maximum number of transform feedback buffers that can be bound for capturing shader outputs from the last vertex processing stage.

- `maxTransformFeedbackBufferSize` is the maximum size that can be specified when binding a buffer for transform feedback in vkCmdBindTransformFeedbackBuffersEXT.

- `maxTransformFeedbackStreamDataSize` is the maximum amount of data in bytes for each vertex that captured to one or more transform feedback buffers associated with a specific vertex stream.

- `maxTransformFeedbackBufferDataSize` is the maximum amount of data in bytes for each vertex that can be captured to a specific transform feedback buffer.

- `maxTransformFeedbackBufferDataStride` is the maximum stride between each capture of vertex data to the buffer.

- `transformFeedbackQueries` is true if the implementation supports the `VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT` query type. `transformFeedbackQueries` is false if queries of this type cannot be created.

- `transformFeedbackStreamsLinesTriangles` is true if the implementation supports the geometry shader `OpExecutionMode` of `OutputLineStrip` and `OutputTriangleStrip` in addition to `OutputPoints` when more than one vertex stream is output. If `transformFeedbackStreamsLinesTriangles` is false the implementation only supports an `OpExecutionMode` of `OutputPoints` when more than one vertex stream is output from the geometry shader.

- `transformFeedbackRasterizationStreamSelect` is true if the implementation supports the `GeometryStreams` SPIR-V capability and the application can use VkPipelineRasterizationStateStreamCreateInfoEXT to modify which vertex stream output is used for rasterization. Otherwise vertex stream `0` must always be used for rasterization.

- `transformFeedbackDraw` is true if the implementation supports the vkCmdDrawIndirectByteCountEXT function otherwise the function must not be called.

If the `VkPhysicalDeviceTransformFeedbackPropertiesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits and properties.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TRANSFORM_FEEDBACK_PROPERTIES_EXT`

The `VkPhysicalDeviceRayTracingPropertiesNV` structure is defined as:

    typedef struct VkPhysicalDeviceRayTracingPropertiesNV {
        VkStructureType    sType;
        void*              pNext;
        uint32_t           shaderGroupHandleSize;
        uint32_t           maxRecursionDepth;
        uint32_t           maxShaderGroupStride;
        uint32_t           shaderGroupBaseAlignment;
        uint64_t           maxGeometryCount;
        uint64_t           maxInstanceCount;
        uint64_t           maxTriangleCount;
        uint32_t           maxDescriptorSetAccelerationStructures;
    } VkPhysicalDeviceRayTracingPropertiesNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `shaderGroupHandleSize` size in bytes of the shader header.

- `maxRecursionDepth` is the maximum number of levels of recursion allowed in a trace command.

- `maxShaderGroupStride` is the maximum stride in bytes allowed between shader groups in the SBT.

- `shaderGroupBaseAlignment` is the required alignment in bytes for the base of the SBTs.

- `maxGeometryCount` is the maximum number of geometries in the bottom level acceleration structure.

- `maxInstanceCount` is the maximum number of instances in the top level acceleration structure.

- `maxTriangleCount` is the maximum number of triangles in all geometries in the bottom level acceleration structure.

- `maxDescriptorSetAccelerationStructures` is the maximum number of acceleration structure descriptors that are allowed in a descriptor set.

If the `VkPhysicalDeviceRayTracingPropertiesNV` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

Limits specified by this structure must match those specified with the same name in VkPhysicalDeviceRayTracingPropertiesKHR.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_RAY_TRACING_PROPERTIES_NV`

The `VkPhysicalDeviceRayTracingPropertiesKHR` structure is defined as:

    typedef struct VkPhysicalDeviceRayTracingPropertiesKHR {
        VkStructureType    sType;
        void*              pNext;
        uint32_t           shaderGroupHandleSize;
        uint32_t           maxRecursionDepth;
        uint32_t           maxShaderGroupStride;
        uint32_t           shaderGroupBaseAlignment;
        uint64_t           maxGeometryCount;
        uint64_t           maxInstanceCount;
        uint64_t           maxPrimitiveCount;
        uint32_t           maxDescriptorSetAccelerationStructures;
        uint32_t           shaderGroupHandleCaptureReplaySize;
    } VkPhysicalDeviceRayTracingPropertiesKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `shaderGroupHandleSize` size in bytes of the shader header.

- `maxRecursionDepth` is the maximum number of levels of recursion allowed in a trace command.

- `maxShaderGroupStride` is the maximum stride in bytes allowed between shader groups in the SBT.

- `shaderGroupBaseAlignment` is the required alignment in bytes for the base of the SBTs.

- `maxGeometryCount` is the maximum number of geometries in the bottom level acceleration structure.

- `maxInstanceCount` is the maximum number of instances in the top level acceleration structure.

- `maxPrimitiveCount` is the maximum number of triangles or AABBs in all geometries in the bottom level acceleration structure.

- `maxDescriptorSetAccelerationStructures` is the maximum number of acceleration structure descriptors that are allowed in a descriptor set.

- `shaderGroupHandleCaptureReplaySize` is the number of bytes for the information required to do capture and replay for shader group handles.

If the `VkPhysicalDeviceRayTracingPropertiesKHR` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

Limits specified by this structure must match those specified with the same name in VkPhysicalDeviceRayTracingPropertiesNV.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_RAY_TRACING_PROPERTIES_KHR`

The `VkPhysicalDeviceCooperativeMatrixPropertiesNV` structure is defined as:

    typedef struct VkPhysicalDeviceCooperativeMatrixPropertiesNV {
        VkStructureType       sType;
        void*                 pNext;
        VkShaderStageFlags    cooperativeMatrixSupportedStages;
    } VkPhysicalDeviceCooperativeMatrixPropertiesNV;

The members of the `VkPhysicalDeviceCooperativeMatrixPropertiesNV` structure describe the following implementation-dependent limits:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `cooperativeMatrixSupportedStages` is a bitfield of VkShaderStageFlagBits describing the shader stages that cooperative matrix instructions are supported in. `cooperativeMatrixSupportedStages` will have the `VK_SHADER_STAGE_COMPUTE_BIT` bit set if any of the physical device’s queues support `VK_QUEUE_COMPUTE_BIT`.

If the `VkPhysicalDeviceCooperativeMatrixPropertiesNV` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_COOPERATIVE_MATRIX_PROPERTIES_NV`

The `VkPhysicalDeviceShaderSMBuiltinsPropertiesNV` structure is defined as:

    typedef struct VkPhysicalDeviceShaderSMBuiltinsPropertiesNV {
        VkStructureType    sType;
        void*              pNext;
        uint32_t           shaderSMCount;
        uint32_t           shaderWarpsPerSM;
    } VkPhysicalDeviceShaderSMBuiltinsPropertiesNV;

The members of the `VkPhysicalDeviceShaderSMBuiltinsPropertiesNV` structure describe the following implementation-dependent limits:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `shaderSMCount` is the number of SMs on the device.

- `shaderWarpsPerSM` is the maximum number of simultaneously executing warps on an SM.

If the `VkPhysicalDeviceShaderSMBuiltinsPropertiesNV` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_SM_BUILTINS_PROPERTIES_NV`

The `VkPhysicalDeviceTexelBufferAlignmentPropertiesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceTexelBufferAlignmentPropertiesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkDeviceSize       storageTexelBufferOffsetAlignmentBytes;
        VkBool32           storageTexelBufferOffsetSingleTexelAlignment;
        VkDeviceSize       uniformTexelBufferOffsetAlignmentBytes;
        VkBool32           uniformTexelBufferOffsetSingleTexelAlignment;
    } VkPhysicalDeviceTexelBufferAlignmentPropertiesEXT;

The members of the `VkPhysicalDeviceTexelBufferAlignmentPropertiesEXT` structure describe the following implementation-dependent limits:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `storageTexelBufferOffsetAlignmentBytes` is a byte alignment that is sufficient for a storage texel buffer of any format.

- `storageTexelBufferOffsetSingleTexelAlignment` indicates whether single texel alignment is sufficient for a storage texel buffer of any format.

- `uniformTexelBufferOffsetAlignmentBytes` is a byte alignment that is sufficient for a uniform texel buffer of any format.

- `uniformTexelBufferOffsetSingleTexelAlignment` indicates whether single texel alignment is sufficient for a uniform texel buffer of any format.

If the `VkPhysicalDeviceTexelBufferAlignmentPropertiesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

If the single texel alignment property is `VK_FALSE`, then the buffer view’s offset must be aligned to the corresponding byte alignment value. If the single texel alignment property is `VK_TRUE`, then the buffer view’s offset must be aligned to the lesser of the corresponding byte alignment value or the size of a single texel, based on VkBufferViewCreateInfo::`format`. If the size of a single texel is a multiple of three bytes, then the size of a single component of the format is used instead.

These limits must not advertise a larger alignment than the required maximum minimum value of VkPhysicalDeviceLimits::`minTexelBufferOffsetAlignment`, for any format that supports use as a texel buffer.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TEXEL_BUFFER_ALIGNMENT_PROPERTIES_EXT`

To query the timeline semaphore properties of a physical device, add a VkPhysicalDeviceTimelineSemaphoreProperties structure to the `pNext` chain of the VkPhysicalDeviceProperties2 structure. The `VkPhysicalDeviceTimelineSemaphoreProperties` structure is defined as:

    typedef struct VkPhysicalDeviceTimelineSemaphoreProperties {
        VkStructureType    sType;
        void*              pNext;
        uint64_t           maxTimelineSemaphoreValueDifference;
    } VkPhysicalDeviceTimelineSemaphoreProperties;

or the equivalent

    typedef VkPhysicalDeviceTimelineSemaphoreProperties VkPhysicalDeviceTimelineSemaphorePropertiesKHR;

The members of the `VkPhysicalDeviceTimelineSemaphoreProperties` structure describe the following implementation-dependent limits:

- `maxTimelineSemaphoreValueDifference` indicates the maximum difference allowed by the implementation between the current value of a timeline semaphore and any pending signal or wait operations.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TIMELINE_SEMAPHORE_PROPERTIES`

The `VkPhysicalDeviceLineRasterizationPropertiesEXT` structure is defined as:

    typedef struct VkPhysicalDeviceLineRasterizationPropertiesEXT {
        VkStructureType    sType;
        void*              pNext;
        uint32_t           lineSubPixelPrecisionBits;
    } VkPhysicalDeviceLineRasterizationPropertiesEXT;

The members of the `VkPhysicalDeviceLineRasterizationPropertiesEXT` structure describe the following implementation-dependent limits:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `lineSubPixelPrecisionBits` is the number of bits of subpixel precision in framebuffer coordinates xf and yf when rasterizing line segments.

If the `VkPhysicalDeviceLineRasterizationPropertiesEXT` structure is included in the `pNext` chain of VkPhysicalDeviceProperties2, it is filled with the implementation-dependent limits.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_LINE_RASTERIZATION_PROPERTIES_EXT`

The `VkPhysicalDeviceDeviceGeneratedCommandsPropertiesNV` structure is defined as:

    typedef struct VkPhysicalDeviceDeviceGeneratedCommandsPropertiesNV {
        VkStructureType    sType;
        const void*        pNext;
        uint32_t           maxGraphicsShaderGroupCount;
        uint32_t           maxIndirectSequenceCount;
        uint32_t           maxIndirectCommandsTokenCount;
        uint32_t           maxIndirectCommandsStreamCount;
        uint32_t           maxIndirectCommandsTokenOffset;
        uint32_t           maxIndirectCommandsStreamStride;
        uint32_t           minSequencesCountBufferOffsetAlignment;
        uint32_t           minSequencesIndexBufferOffsetAlignment;
        uint32_t           minIndirectCommandsBufferOffsetAlignment;
    } VkPhysicalDeviceDeviceGeneratedCommandsPropertiesNV;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `maxGraphicsShaderGroupCount` the maximum number of shader groups in `VkGraphicsPipelineShaderGroupsCreateInfoNV`.

- `maxIndirectSequenceCount` the maximum number of sequences in in `VkGeneratedCommandsInfoNV` or `VkGeneratedCommandsMemoryRequirementsInfoNV`.

- `maxIndirectCommandsLayoutTokenCount` the maximum number of tokens in `VkIndirectCommandsLayoutCreateInfoNV`.

- `maxIndirectCommandsStreamCount` the maximum number of streams in `VkIndirectCommandsLayoutCreateInfoNV`.

- `maxIndirectCommandsTokenOffset` the maximum offset in `VkIndirectCommandsLayoutTokenNV`.

- `maxIndirectCommandsStreamStride` the maximum stream stride in `VkIndirectCommandsLayoutCreateInfoNV`.

- `minSequenceCountBufferOffsetAlignment` the minimum alignment for memory addresses optionally used in `VkGeneratedCommandsInfoNV`.

- `minSequenceIndexBufferOffsetAlignment` the minimum alignment for memory addresses optionally used in `VkGeneratedCommandsInfoNV`.

- `minIndirectCommandsBufferOffsetAlignment` the minimum alignment for memory addresses used in `VkIndirectCommandsStreamNV` and as preprocess buffer in `VkGeneratedCommandsInfoNV`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DEVICE_GENERATED_COMMANDS_PROPERTIES_NV`

### 38.1. Limit Requirements

The following table specifies the required minimum/maximum for all Vulkan graphics implementations. Where a limit corresponds to a fine-grained device feature which is optional, the feature name is listed with two required limits, one when the feature is supported and one when it is not supported. If an implementation supports a feature, the limits reported are the same whether or not the feature is enabled.

Table 45. Required Limit Types
Type | Limit | Feature
--- | --- | ---
`uint32_t` | `maxImageDimension1D` | -
`uint32_t` | `maxImageDimension2D` | -
`uint32_t` | `maxImageDimension3D` | -
`uint32_t` | `maxImageDimensionCube` | -
`uint32_t` | `maxImageArrayLayers` | -
`uint32_t` | `maxTexelBufferElements` | -
`uint32_t` | `maxUniformBufferRange` | -
`uint32_t` | `maxStorageBufferRange` | -
`uint32_t` | `maxPushConstantsSize` | -
`uint32_t` | `maxMemoryAllocationCount` | -
`uint32_t` | `maxSamplerAllocationCount` | -
`VkDeviceSize` | `bufferImageGranularity` | -
`VkDeviceSize` | `sparseAddressSpaceSize` | `sparseBinding`
`uint32_t` | `maxBoundDescriptorSets` | -
`uint32_t` | `maxPerStageDescriptorSamplers` | -
`uint32_t` | `maxPerStageDescriptorUniformBuffers` | -
`uint32_t` | `maxPerStageDescriptorStorageBuffers` | -
`uint32_t` | `maxPerStageDescriptorSampledImages` | -
`uint32_t` | `maxPerStageDescriptorStorageImages` | -
`uint32_t` | `maxPerStageDescriptorInputAttachments` | -
`uint32_t` | `maxPerStageResources` | -
`uint32_t` | `maxDescriptorSetSamplers` | -
`uint32_t` | `maxDescriptorSetUniformBuffers` | -
`uint32_t` | `maxDescriptorSetUniformBuffersDynamic` | -
`uint32_t` | `maxDescriptorSetStorageBuffers` | -
`uint32_t` | `maxDescriptorSetStorageBuffersDynamic` | -
`uint32_t` | `maxDescriptorSetSampledImages` | -
`uint32_t` | `maxDescriptorSetStorageImages` | -
`uint32_t` | `maxDescriptorSetInputAttachments` | -
`uint32_t` | `maxVertexInputAttributes` | -
`uint32_t` | `maxVertexInputBindings` | -
`uint32_t` | `maxVertexInputAttributeOffset` | -
`uint32_t` | `maxVertexInputBindingStride` | -
`uint32_t` | `maxVertexOutputComponents` | -
`uint32_t` | `maxTessellationGenerationLevel` | `tessellationShader`
`uint32_t` | `maxTessellationPatchSize` | `tessellationShader`
`uint32_t` | `maxTessellationControlPerVertexInputComponents` | `tessellationShader`
`uint32_t` | `maxTessellationControlPerVertexOutputComponents` | `tessellationShader`
`uint32_t` | `maxTessellationControlPerPatchOutputComponents` | `tessellationShader`
`uint32_t` | `maxTessellationControlTotalOutputComponents` | `tessellationShader`
`uint32_t` | `maxTessellationEvaluationInputComponents` | `tessellationShader`
`uint32_t` | `maxTessellationEvaluationOutputComponents` | `tessellationShader`
`uint32_t` | `maxGeometryShaderInvocations` | `geometryShader`
`uint32_t` | `maxGeometryInputComponents` | `geometryShader`
`uint32_t` | `maxGeometryOutputComponents` | `geometryShader`
`uint32_t` | `maxGeometryOutputVertices` | `geometryShader`
`uint32_t` | `maxGeometryTotalOutputComponents` | `geometryShader`
`uint32_t` | `maxFragmentInputComponents` | -
`uint32_t` | `maxFragmentOutputAttachments` | -
`uint32_t` | `maxFragmentDualSrcAttachments` | `dualSrcBlend`
`uint32_t` | `maxFragmentCombinedOutputResources` | -
`uint32_t` | `maxComputeSharedMemorySize` | -
3 × `uint32_t` | `maxComputeWorkGroupCount` | -
`uint32_t` | `maxComputeWorkGroupInvocations` | -
3 × `uint32_t` | `maxComputeWorkGroupSize` | -
`uint32_t` | `subPixelPrecisionBits` | -
`uint32_t` | `subTexelPrecisionBits` | -
`uint32_t` | `mipmapPrecisionBits` | -
`uint32_t` | `maxDrawIndexedIndexValue` | `fullDrawIndexUint32`
`uint32_t` | `maxDrawIndirectCount` | `multiDrawIndirect`
`float` | `maxSamplerLodBias` | -
`float` | `maxSamplerAnisotropy` | `samplerAnisotropy`
`uint32_t` | `maxViewports` | `multiViewport`
2 × `uint32_t` | `maxViewportDimensions` | -
2 × `float` | `viewportBoundsRange` | -
`uint32_t` | `viewportSubPixelBits` | -
`size_t` | `minMemoryMapAlignment` | -
`VkDeviceSize` | `minTexelBufferOffsetAlignment` | -
`VkDeviceSize` | `minUniformBufferOffsetAlignment` | -
`VkDeviceSize` | `minStorageBufferOffsetAlignment` | -
`int32_t` | `minTexelOffset` | -
`uint32_t` | `maxTexelOffset` | -
`int32_t` | `minTexelGatherOffset` | `shaderImageGatherExtended`
`uint32_t` | `maxTexelGatherOffset` | `shaderImageGatherExtended`
`float` | `minInterpolationOffset` | `sampleRateShading`
`float` | `maxInterpolationOffset` | `sampleRateShading`
`uint32_t` | `subPixelInterpolationOffsetBits` | `sampleRateShading`
`uint32_t` | `maxFramebufferWidth` | -
`uint32_t` | `maxFramebufferHeight` | -
`uint32_t` | `maxFramebufferLayers` | -
VkSampleCountFlags | `framebufferColorSampleCounts` | -
VkSampleCountFlags | `framebufferIntegerColorSampleCounts` | -
VkSampleCountFlags | `framebufferDepthSampleCounts` | -
VkSampleCountFlags | `framebufferStencilSampleCounts` | -
VkSampleCountFlags | `framebufferNoAttachmentsSampleCounts` | -
`uint32_t` | `maxColorAttachments` | -
VkSampleCountFlags | `sampledImageColorSampleCounts` | -
VkSampleCountFlags | `sampledImageIntegerSampleCounts` | -
VkSampleCountFlags | `sampledImageDepthSampleCounts` | -
VkSampleCountFlags | `sampledImageStencilSampleCounts` | -
VkSampleCountFlags | `storageImageSampleCounts` | `shaderStorageImageMultisample`
`uint32_t` | `maxSampleMaskWords` | -
`VkBool32` | `timestampComputeAndGraphics` | -
`float` | `timestampPeriod` | -
`uint32_t` | `maxClipDistances` | `shaderClipDistance`
`uint32_t` | `maxCullDistances` | `shaderCullDistance`
`uint32_t` | `maxCombinedClipAndCullDistances` | `shaderCullDistance`
`uint32_t` | `discreteQueuePriorities` | -
2 × `float` | `pointSizeRange` | `largePoints`
2 × `float` | `lineWidthRange` | `wideLines`
`float` | `pointSizeGranularity` | `largePoints`
`float` | `lineWidthGranularity` | `wideLines`
`VkBool32` | `strictLines` | -
`VkBool32` | `standardSampleLocations` | -
`VkDeviceSize` | `optimalBufferCopyOffsetAlignment` | -
`VkDeviceSize` | `optimalBufferCopyRowPitchAlignment` | -
`VkDeviceSize` | `nonCoherentAtomSize` | -
`uint32_t` | `maxDiscardRectangles` | `VK_EXT_discard_rectangles`
`VkBool32` | `filterMinmaxSingleComponentFormats` | `VK_EXT_sampler_filter_minmax`
`VkBool32` | `filterMinmaxImageComponentMapping` | `VK_EXT_sampler_filter_minmax`
`float` | `primitiveOverestimationSize` | `VK_EXT_conservative_rasterization`
`VkBool32` | `maxExtraPrimitiveOverestimationSize` | `VK_EXT_conservative_rasterization`
`float` | `extraPrimitiveOverestimationSizeGranularity` | `VK_EXT_conservative_rasterization`
`VkBool32` | `degenerateTriangleRasterized` | `VK_EXT_conservative_rasterization`
`float` | `degenerateLinesRasterized` | `VK_EXT_conservative_rasterization`
`VkBool32` | `fullyCoveredFragmentShaderInputVariable` | `VK_EXT_conservative_rasterization`
`VkBool32` | `conservativeRasterizationPostDepthCoverage` | `VK_EXT_conservative_rasterization`
`uint32_t` | `maxUpdateAfterBindDescriptorsInAllPools` | ``descriptorIndexing``
`VkBool32` | `shaderUniformBufferArrayNonUniformIndexingNative` | -
`VkBool32` | `shaderSampledImageArrayNonUniformIndexingNative` | -
`VkBool32` | `shaderStorageBufferArrayNonUniformIndexingNative` | -
`VkBool32` | `shaderStorageImageArrayNonUniformIndexingNative` | -
`VkBool32` | `shaderInputAttachmentArrayNonUniformIndexingNative` | -
`uint32_t` | `maxPerStageDescriptorUpdateAfterBindSamplers` | ``descriptorIndexing``
`uint32_t` | `maxPerStageDescriptorUpdateAfterBindUniformBuffers` | ``descriptorIndexing``
`uint32_t` | `maxPerStageDescriptorUpdateAfterBindStorageBuffers` | ``descriptorIndexing``
`uint32_t` | `maxPerStageDescriptorUpdateAfterBindSampledImages` | ``descriptorIndexing``
`uint32_t` | `maxPerStageDescriptorUpdateAfterBindStorageImages` | ``descriptorIndexing``
`uint32_t` | `maxPerStageDescriptorUpdateAfterBindInputAttachments` | ``descriptorIndexing``
`uint32_t` | `maxPerStageUpdateAfterBindResources` | ``descriptorIndexing``
`uint32_t` | `maxDescriptorSetUpdateAfterBindSamplers` | ``descriptorIndexing``
`uint32_t` | `maxDescriptorSetUpdateAfterBindUniformBuffers` | ``descriptorIndexing``
`uint32_t` | `maxDescriptorSetUpdateAfterBindUniformBuffersDynamic` | ``descriptorIndexing``
`uint32_t` | `maxDescriptorSetUpdateAfterBindStorageBuffers` | ``descriptorIndexing``
`uint32_t` | `maxDescriptorSetUpdateAfterBindStorageBuffersDynamic` | ``descriptorIndexing``
`uint32_t` | `maxDescriptorSetUpdateAfterBindSampledImages` | ``descriptorIndexing``
`uint32_t` | `maxDescriptorSetUpdateAfterBindStorageImages` | ``descriptorIndexing``
`uint32_t` | `maxDescriptorSetUpdateAfterBindInputAttachments` | ``descriptorIndexing``
`uint32_t` | `maxVertexAttribDivisor` | `VK_EXT_vertex_attribute_divisor`
`uint32_t` | `maxDrawMeshTasksCount` | `VK_NV_mesh_shader`
`uint32_t` | `maxTaskWorkGroupInvocations` | `VK_NV_mesh_shader`
`uint32_t` | `maxTaskWorkGroupSize` | `VK_NV_mesh_shader`
`uint32_t` | `maxTaskTotalMemorySize` | `VK_NV_mesh_shader`
`uint32_t` | `maxTaskOutputCount` | `VK_NV_mesh_shader`
`uint32_t` | `maxMeshWorkGroupInvocations` | `VK_NV_mesh_shader`
`uint32_t` | `maxMeshWorkGroupSize` | `VK_NV_mesh_shader`
`uint32_t` | `maxMeshTotalMemorySize` | `VK_NV_mesh_shader`
`uint32_t` | `maxMeshOutputVertices` | `VK_NV_mesh_shader`
`uint32_t` | `maxMeshOutputPrimitives` | `VK_NV_mesh_shader`
`uint32_t` | `maxMeshMultiviewViewCount` | `VK_NV_mesh_shader`
`uint32_t` | `meshOutputPerVertexGranularity` | `VK_NV_mesh_shader`
`uint32_t` | `meshOutputPerPrimitiveGranularity` | `VK_NV_mesh_shader`
`uint32_t` | `maxTransformFeedbackStreams` | `VK_EXT_transform_feedback`
`uint32_t` | `maxTransformFeedbackBuffers` | `VK_EXT_transform_feedback`
`VkDeviceSize` | `maxTransformFeedbackBufferSize` | `VK_EXT_transform_feedback`
`uint32_t` | `maxTransformFeedbackStreamDataSize` | `VK_EXT_transform_feedback`
`uint32_t` | `maxTransformFeedbackBufferDataSize` | `VK_EXT_transform_feedback`
`uint32_t` | `maxTransformFeedbackBufferDataStride` | `VK_EXT_transform_feedback`
`VkBool32` | `transformFeedbackQueries` | `VK_EXT_transform_feedback`
`VkBool32` | `transformFeedbackStreamsLinesTriangles` | `VK_EXT_transform_feedback`
`VkBool32` | `transformFeedbackRasterizationStreamSelect` | `VK_EXT_transform_feedback`
`VkBool32` | `transformFeedbackDraw` | `VK_EXT_transform_feedback`
VkExtent2D | `minFragmentDensityTexelSize` | `fragmentDensityMap`
VkExtent2D | `maxFragmentDensityTexelSize` | `fragmentDensityMap`
`VkBool32` | `fragmentDensityInvocations` | `fragmentDensityMap`
`uint32_t` | `shaderGroupHandleSize` | `VK_NV_ray_tracing`, `VK_KHR_ray_tracing`
`uint32_t` | `maxRecursionDepth` | `VK_NV_ray_tracing`, `VK_KHR_ray_tracing`
`uint32_t` | `shaderGroupBaseAlignment` | `VK_NV_ray_tracing`, `VK_KHR_ray_tracing`
`uint32_t` | `maxGeometryCount` | `VK_NV_ray_tracing`, `VK_KHR_ray_tracing`
`uint32_t` | `maxInstanceCount` | `VK_NV_ray_tracing`, `VK_KHR_ray_tracing`
`uint32_t` | `maxTriangleCount` | `VK_NV_ray_tracing`
`uint32_t` | `maxPrimitiveCount` | `VK_KHR_ray_tracing`
`uint32_t` | `maxDescriptorSetAccelerationStructures` | `VK_NV_ray_tracing`, `VK_KHR_ray_tracing`
`uint64_t` | `maxTimelineSemaphoreValueDifference` | ``timelineSemaphore``
`uint32_t` | `lineSubPixelPrecisionBits` | `VK_EXT_line_rasterization`

Table 46. Required Limits
Limit | Unsupported Limit | Supported Limit | Limit Type1
--- | --- | --- | ---
`maxImageDimension1D` | - | 4096 | min
`maxImageDimension2D` | - | 4096 | min
`maxImageDimension3D` | - | 256 | min
`maxImageDimensionCube` | - | 4096 | min
`maxImageArrayLayers` | - | 256 | min
`maxTexelBufferElements` | - | 65536 | min
`maxUniformBufferRange` | - | 16384 | min
`maxStorageBufferRange` | - | 227 | min
`maxPushConstantsSize` | - | 128 | min
`maxMemoryAllocationCount` | - | 4096 | min
`maxSamplerAllocationCount` | - | 4000 | min
`bufferImageGranularity` | - | 131072 | max
`sparseAddressSpaceSize` | 0 | 231 | min
`maxBoundDescriptorSets` | - | 4 | min
`maxPerStageDescriptorSamplers` | - | 16 | min
`maxPerStageDescriptorUniformBuffers` | - | 12 | min
`maxPerStageDescriptorStorageBuffers` | - | 4 | min
`maxPerStageDescriptorSampledImages` | - | 16 | min
`maxPerStageDescriptorStorageImages` | - | 4 | min
`maxPerStageDescriptorInputAttachments` | - | 4 | min
`maxPerStageResources` | - | 128 2 | min
`maxDescriptorSetSamplers` | - | 96 8 | min, n × PerStage
`maxDescriptorSetUniformBuffers` | - | 72 8 | min, n × PerStage
`maxDescriptorSetUniformBuffersDynamic` | - | 8 | min
`maxDescriptorSetStorageBuffers` | - | 24 8 | min, n × PerStage
`maxDescriptorSetStorageBuffersDynamic` | - | 4 | min
`maxDescriptorSetSampledImages` | - | 96 8 | min, n × PerStage
`maxDescriptorSetStorageImages` | - | 24 8 | min, n × PerStage
`maxDescriptorSetInputAttachments` | - | 4 | min
`maxVertexInputAttributes` | - | 16 | min
`maxVertexInputBindings` | - | 16 | min
`maxVertexInputAttributeOffset` | - | 2047 | min
`maxVertexInputBindingStride` | - | 2048 | min
`maxVertexOutputComponents` | - | 64 | min
`maxTessellationGenerationLevel` | 0 | 64 | min
`maxTessellationPatchSize` | 0 | 32 | min
`maxTessellationControlPerVertexInputComponents` | 0 | 64 | min
`maxTessellationControlPerVertexOutputComponents` | 0 | 64 | min
`maxTessellationControlPerPatchOutputComponents` | 0 | 120 | min
`maxTessellationControlTotalOutputComponents` | 0 | 2048 | min
`maxTessellationEvaluationInputComponents` | 0 | 64 | min
`maxTessellationEvaluationOutputComponents` | 0 | 64 | min
`maxGeometryShaderInvocations` | 0 | 32 | min
`maxGeometryInputComponents` | 0 | 64 | min
`maxGeometryOutputComponents` | 0 | 64 | min
`maxGeometryOutputVertices` | 0 | 256 | min
`maxGeometryTotalOutputComponents` | 0 | 1024 | min
`maxFragmentInputComponents` | - | 64 | min
`maxFragmentOutputAttachments` | - | 4 | min
`maxFragmentDualSrcAttachments` | 0 | 1 | min
`maxFragmentCombinedOutputResources` | - | 4 | min
`maxComputeSharedMemorySize` | - | 16384 | min
`maxComputeWorkGroupCount` | - | (65535,65535,65535) | min
`maxComputeWorkGroupInvocations` | - | 128 | min
`maxComputeWorkGroupSize` | - | (128,128,64) | min
`subPixelPrecisionBits` | - | 4 | min
`subTexelPrecisionBits` | - | 4 | min
`mipmapPrecisionBits` | - | 4 | min
`maxDrawIndexedIndexValue` | 224-1 | 232-1 | min
`maxDrawIndirectCount` | 1 | 216-1 | min
`maxSamplerLodBias` | - | 2 | min
`maxSamplerAnisotropy` | 1 | 16 | min
`maxViewports` | 1 | 16 | min
`maxViewportDimensions` | - | (4096,4096) 3 | min
`viewportBoundsRange` | - | (-8192,8191) 4 | (max,min)
`viewportSubPixelBits` | - | 0 | min
`minMemoryMapAlignment` | - | 64 | min
`minTexelBufferOffsetAlignment` | - | 256 | max
`minUniformBufferOffsetAlignment` | - | 256 | max
`minStorageBufferOffsetAlignment` | - | 256 | max
`minTexelOffset` | - | -8 | max
`maxTexelOffset` | - | 7 | min
`minTexelGatherOffset` | 0 | -8 | max
`maxTexelGatherOffset` | 0 | 7 | min
`minInterpolationOffset` | 0.0 | -0.5 5 | max
`maxInterpolationOffset` | 0.0 | 0.5 - (1 ULP) 5 | min
`subPixelInterpolationOffsetBits` | 0 | 4 5 | min
`maxFramebufferWidth` | - | 4096 | min
`maxFramebufferHeight` | - | 4096 | min
`maxFramebufferLayers` | - | 256 | min
`framebufferColorSampleCounts` | - | (`VK_SAMPLE_COUNT_1_BIT` | `VK_SAMPLE_COUNT_4_BIT`) | min
`framebufferIntegerColorSampleCounts` | - | (`VK_SAMPLE_COUNT_1_BIT`) | min
`framebufferDepthSampleCounts` | - | (`VK_SAMPLE_COUNT_1_BIT` | `VK_SAMPLE_COUNT_4_BIT`) | min
`framebufferStencilSampleCounts` | - | (`VK_SAMPLE_COUNT_1_BIT` | `VK_SAMPLE_COUNT_4_BIT`) | min
`framebufferNoAttachmentsSampleCounts` | - | (`VK_SAMPLE_COUNT_1_BIT` | `VK_SAMPLE_COUNT_4_BIT`) | min
`maxColorAttachments` | - | 4 | min
`sampledImageColorSampleCounts` | - | (`VK_SAMPLE_COUNT_1_BIT` | `VK_SAMPLE_COUNT_4_BIT`) | min
`sampledImageIntegerSampleCounts` | - | `VK_SAMPLE_COUNT_1_BIT` | min
`sampledImageDepthSampleCounts` | - | (`VK_SAMPLE_COUNT_1_BIT` | `VK_SAMPLE_COUNT_4_BIT`) | min
`sampledImageStencilSampleCounts` | - | (`VK_SAMPLE_COUNT_1_BIT` | `VK_SAMPLE_COUNT_4_BIT`) | min
`storageImageSampleCounts` | `VK_SAMPLE_COUNT_1_BIT` | (`VK_SAMPLE_COUNT_1_BIT` | `VK_SAMPLE_COUNT_4_BIT`) | min
`maxSampleMaskWords` | - | 1 | min
`timestampComputeAndGraphics` | - | - | implementation dependent
`timestampPeriod` | - | - | duration
`maxClipDistances` | 0 | 8 | min
`maxCullDistances` | 0 | 8 | min
`maxCombinedClipAndCullDistances` | 0 | 8 | min
`discreteQueuePriorities` | - | 2 | min
`pointSizeRange` | (1.0,1.0) | (1.0,64.0 - ULP)6 | (max,min)
`lineWidthRange` | (1.0,1.0) | (1.0,8.0 - ULP)7 | (max,min)
`pointSizeGranularity` | 0.0 | 1.0 6 | max, fixed point increment
`lineWidthGranularity` | 0.0 | 1.0 7 | max, fixed point increment
`strictLines` | - | - | implementation dependent
`standardSampleLocations` | - | - | implementation dependent
`optimalBufferCopyOffsetAlignment` | - | - | recommendation
`optimalBufferCopyRowPitchAlignment` | - | - | recommendation
`nonCoherentAtomSize` | - | 256 | max
`maxPushDescriptors` | - | 32 | min
`maxMultiviewViewCount` | - | 6 | min
`maxMultiviewInstanceIndex` | - | 227-1 | min
`maxDiscardRectangles` | 0 | 4 | min
`sampleLocationSampleCounts` | - | `VK_SAMPLE_COUNT_4_BIT` | min
`maxSampleLocationGridSize` | - | (1,1) | min
`sampleLocationCoordinateRange` | - | (0.0, 0.9375) | (max,min)
`sampleLocationSubPixelBits` | - | 4 | min
`variableSampleLocations` | - | false | implementation dependent
`minImportedHostPointerAlignment` | - | 65536 | max
`perViewPositionAllComponents` | - | - | implementation dependent
`filterMinmaxSingleComponentFormats` | - | - | implementation dependent
`filterMinmaxImageComponentMapping` | - | - | implementation dependent
`advancedBlendMaxColorAttachments` | - | 1 | min
`advancedBlendIndependentBlend` | - | false | implementation dependent
`advancedBlendNonPremultipliedSrcColor` | - | false | implementation dependent
`advancedBlendNonPremultipliedDstColor` | - | false | implementation dependent
`advancedBlendCorrelatedOverlap` | - | false | implementation dependent
`advancedBlendAllOperations` | - | false | implementation dependent
`maxPerSetDescriptors` | - | 1024 | min
`maxMemoryAllocationSize` | - | 230 | min
`primitiveOverestimationSize` | - | 0.0 | min
`maxExtraPrimitiveOverestimationSize` | - | 0.0 | min
`extraPrimitiveOverestimationSizeGranularity` | - | 0.0 | min
`primitiveUnderestimation` | - | false | implementation dependent
`conservativePointAndLineRasterization` | - | false | implementation dependent
`degenerateTrianglesRasterized` | - | false | implementation dependent
`degenerateLinesRasterized` | - | false | implementation dependent
`fullyCoveredFragmentShaderInputVariable` | - | false | implementation dependent
`conservativeRasterizationPostDepthCoverage` | - | false | implementation dependent
`maxUpdateAfterBindDescriptorsInAllPools` | 0 | 500000 | min
`shaderUniformBufferArrayNonUniformIndexingNative` | - | false | implementation dependent
`shaderSampledImageArrayNonUniformIndexingNative` | - | false | implementation dependent
`shaderStorageBufferArrayNonUniformIndexingNative` | - | false | implementation dependent
`shaderStorageImageArrayNonUniformIndexingNative` | - | false | implementation dependent
`shaderInputAttachmentArrayNonUniformIndexingNative` | - | false | implementation dependent
`maxPerStageDescriptorUpdateAfterBindSamplers` | 0 | 500000 9 | min
`maxPerStageDescriptorUpdateAfterBindUniformBuffers` | 0 | 12 9 | min
`maxPerStageDescriptorUpdateAfterBindStorageBuffers` | 0 | 500000 9 | min
`maxPerStageDescriptorUpdateAfterBindSampledImages` | 0 | 500000 9 | min
`maxPerStageDescriptorUpdateAfterBindStorageImages` | 0 | 500000 9 | min
`maxPerStageDescriptorUpdateAfterBindInputAttachments` | 0 | 4 9 | min
`maxPerStageUpdateAfterBindResources` | 0 | 500000 9 | min
`maxDescriptorSetUpdateAfterBindSamplers` | 0 | 500000 9 | min
`maxDescriptorSetUpdateAfterBindUniformBuffers` | 0 | 72 8 9 | min, n × PerStage
`maxDescriptorSetUpdateAfterBindUniformBuffersDynamic` | 0 | 8 9 | min
`maxDescriptorSetUpdateAfterBindStorageBuffers` | 0 | 500000 9 | min
`maxDescriptorSetUpdateAfterBindStorageBuffersDynamic` | 0 | 4 9 | min
`maxDescriptorSetUpdateAfterBindSampledImages` | 0 | 500000 9 | min
`maxDescriptorSetUpdateAfterBindStorageImages` | 0 | 500000 9 | min
`maxDescriptorSetUpdateAfterBindInputAttachments` | 0 | 4 9 | min
`maxInlineUniformBlockSize` | - | 256 | min
`maxPerStageDescriptorInlineUniformBlocks` | - | 4 | min
`maxPerStageDescriptorUpdateAfterBindInlineUniformBlocks` | - | 4 | min
`maxDescriptorSetInlineUniformBlocks` | - | 4 | min
`maxDescriptorSetUpdateAfterBindInlineUniformBlocks` | - | 4 | min
`maxVertexAttribDivisor` | - | 216-1 | min
`maxDrawMeshTasksCount` | - | 216-1 | min
`maxTaskWorkGroupInvocations` | - | 32 | min
`maxTaskWorkGroupSize` | - | (32,1,1) | min
`maxTaskTotalMemorySize` | - | 16384 | min
`maxTaskOutputCount` | - | 216-1 | min
`maxMeshWorkGroupInvocations` | - | 32 | min
`maxMeshWorkGroupSize` | - | (32,1,1) | min
`maxMeshTotalMemorySize` | - | 16384 | min
`maxMeshOutputVertices` | - | 256 | min
`maxMeshOutputPrimitives` | - | 256 | min
`maxMeshMultiviewViewCount` | - | 1 | min
`meshOutputPerVertexGranularity` | - | - | implementation dependent
`meshOutputPerPrimitiveGranularity` | - | - | implementation dependent
`maxTransformFeedbackStreams` | - | 1 | min
`maxTransformFeedbackBuffers` | - | 1 | min
`maxTransformFeedbackBufferSize` | - | 227 | min
`maxTransformFeedbackStreamDataSize` | - | 512 | min
`maxTransformFeedbackBufferDataSize` | - | 512 | min
`maxTransformFeedbackBufferDataStride` | - | 512 | min
`transformFeedbackQueries` | - | false | implementation dependent
`transformFeedbackStreamsLinesTriangles` | - | false | implementation dependent
`transformFeedbackRasterizationStreamSelect` | - | false | implementation dependent
`transformFeedbackDraw` | - | false | implementation dependent
`minFragmentDensityTexelSize` | - | (1,1) | min
`maxFragmentDensityTexelSize` | - | (1,1) | min
`fragmentDensityInvocations` | - | - | implementation dependent
`shaderGroupHandleSize` | - | 32 | exact
`maxRecursionDepth` | - | 31 | min
`shaderGroupBaseAlignment` | - | 64 | max
`maxGeometryCount` | - | 224-1 | min
`maxInstanceCount` | - | 224-1 | min
`maxTriangleCount` | - | 229-1 | min
`maxPrimitiveCount` | - | 229-1 | min
`maxDescriptorSetAccelerationStructures` | - | 16 | min
`maxTimelineSemaphoreValueDifference` | - | 231-1 | min
`lineSubPixelPrecisionBits` | - | 4 | min
`maxGraphicsShaderGroupCount` | - | 2^12 | min
`maxIndirectSequenceCount` | - | 2^20 | min
`maxIndirectCommandsTokenCount` | - | 16 | min
`maxIndirectCommandsStreamCount` | - | 16 | min
`maxIndirectCommandsTokenOffset` | - | 2047 | min
`maxIndirectCommandsStreamStride` | - | 2048 | min
`minSequencesCountBufferOffsetAlignment` | - | 256 | max
`minSequencesIndexBufferOffsetAlignment` | - | 256 | max
`minIndirectCommandsBufferOffsetAlignment` | - | 256 | max

1

  The Limit Type column specifies the limit is either the minimum limit all implementations must support, the maximum limit all implementations must support, or the exact value all implementations must support. For bitmasks a minimum limit is the least bits all implementations must set, but they may have additional bits set beyond this minimum.

2

  The `maxPerStageResources` must be at least the smallest of the following:

  - the sum of the `maxPerStageDescriptorUniformBuffers`, `maxPerStageDescriptorStorageBuffers`, `maxPerStageDescriptorSampledImages`, `maxPerStageDescriptorStorageImages`, `maxPerStageDescriptorInputAttachments`, `maxColorAttachments` limits, or

  - 128.

  It may not be possible to reach this limit in every stage.

3

  See `maxViewportDimensions` for the required relationship to other limits.

4

  See `viewportBoundsRange` for the required relationship to other limits.

5

  The values `minInterpolationOffset` and `maxInterpolationOffset` describe the closed interval of supported interpolation offsets: [`minInterpolationOffset`, `maxInterpolationOffset`]. The ULP is determined by `subPixelInterpolationOffsetBits`. If `subPixelInterpolationOffsetBits` is 4, this provides increments of (1/24) = 0.0625, and thus the range of supported interpolation offsets would be [-0.5, 0.4375].

6

  The point size ULP is determined by `pointSizeGranularity`. If the `pointSizeGranularity` is 0.125, the range of supported point sizes must be at least [1.0, 63.875].

7

  The line width ULP is determined by `lineWidthGranularity`. If the `lineWidthGranularity` is 0.0625, the range of supported line widths must be at least [1.0, 7.9375].

8

  The minimum `maxDescriptorSet*` limit is n times the corresponding specification minimum `maxPerStageDescriptor*` limit, where n is the number of shader stages supported by the VkPhysicalDevice. If all shader stages are supported, n = 6 (vertex, tessellation control, tessellation evaluation, geometry, fragment, compute).

9

  The `UpdateAfterBind` descriptor limits must each be greater than or equal to the corresponding `non`-UpdateAfterBind limit.

### 38.2. Additional Multisampling Capabilities

In addition to the minimum capabilities described for (Limits) above, implementations may support additional multisampling capabilities specific to a particular sample count.

To query additional sample count specific multisampling capabilities, call:

    void vkGetPhysicalDeviceMultisamplePropertiesEXT(
        VkPhysicalDevice                            physicalDevice,
        VkSampleCountFlagBits                       samples,
        VkMultisamplePropertiesEXT*                 pMultisampleProperties);

- `physicalDevice` is the physical device from which to query the additional multisampling capabilities.

- `samples` is the sample count to query the capabilities for.

- `pMultisampleProperties` is a pointer to a VkMultisamplePropertiesEXT structure in which information about the additional multisampling capabilities specific to the sample count is returned.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `samples` must be a valid VkSampleCountFlagBits value

- `pMultisampleProperties` must be a valid pointer to a VkMultisamplePropertiesEXT structure

The `VkMultisamplePropertiesEXT` structure is defined as

    typedef struct VkMultisamplePropertiesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkExtent2D         maxSampleLocationGridSize;
    } VkMultisamplePropertiesEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `maxSampleLocationGridSize` is the maximum size of the pixel grid in which sample locations can vary.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_MULTISAMPLE_PROPERTIES_EXT`

- `pNext` must be `NULL`

If the sample count for which additional multisampling capabilities are requested using `vkGetPhysicalDeviceMultisamplePropertiesEXT` is set in `VkPhysicalDeviceSampleLocationsPropertiesEXT`:: `sampleLocationSampleCounts` the `width` and `height` members of `VkMultisamplePropertiesEXT`::`maxSampleLocationGridSize` must be greater than or equal to the corresponding members of `VkPhysicalDeviceSampleLocationsPropertiesEXT`:: `maxSampleLocationGridSize`, respectively, otherwise both members must be `0`.

## 39. Formats

Supported buffer and image formats may vary across implementations. A minimum set of format features are guaranteed, but others must be explicitly queried before use to ensure they are supported by the implementation.

The features for the set of formats (VkFormat) supported by the implementation are queried individually using the vkGetPhysicalDeviceFormatProperties command.

### 39.1. Format Definition

The following image formats can be passed to, and may be returned from Vulkan commands. The memory required to store each format is discussed with that format, and also summarized in the Representation and Texel Block Size section and the Compatible formats table.

    typedef enum VkFormat {
        VK_FORMAT_UNDEFINED = 0,
        VK_FORMAT_R4G4_UNORM_PACK8 = 1,
        VK_FORMAT_R4G4B4A4_UNORM_PACK16 = 2,
        VK_FORMAT_B4G4R4A4_UNORM_PACK16 = 3,
        VK_FORMAT_R5G6B5_UNORM_PACK16 = 4,
        VK_FORMAT_B5G6R5_UNORM_PACK16 = 5,
        VK_FORMAT_R5G5B5A1_UNORM_PACK16 = 6,
        VK_FORMAT_B5G5R5A1_UNORM_PACK16 = 7,
        VK_FORMAT_A1R5G5B5_UNORM_PACK16 = 8,
        VK_FORMAT_R8_UNORM = 9,
        VK_FORMAT_R8_SNORM = 10,
        VK_FORMAT_R8_USCALED = 11,
        VK_FORMAT_R8_SSCALED = 12,
        VK_FORMAT_R8_UINT = 13,
        VK_FORMAT_R8_SINT = 14,
        VK_FORMAT_R8_SRGB = 15,
        VK_FORMAT_R8G8_UNORM = 16,
        VK_FORMAT_R8G8_SNORM = 17,
        VK_FORMAT_R8G8_USCALED = 18,
        VK_FORMAT_R8G8_SSCALED = 19,
        VK_FORMAT_R8G8_UINT = 20,
        VK_FORMAT_R8G8_SINT = 21,
        VK_FORMAT_R8G8_SRGB = 22,
        VK_FORMAT_R8G8B8_UNORM = 23,
        VK_FORMAT_R8G8B8_SNORM = 24,
        VK_FORMAT_R8G8B8_USCALED = 25,
        VK_FORMAT_R8G8B8_SSCALED = 26,
        VK_FORMAT_R8G8B8_UINT = 27,
        VK_FORMAT_R8G8B8_SINT = 28,
        VK_FORMAT_R8G8B8_SRGB = 29,
        VK_FORMAT_B8G8R8_UNORM = 30,
        VK_FORMAT_B8G8R8_SNORM = 31,
        VK_FORMAT_B8G8R8_USCALED = 32,
        VK_FORMAT_B8G8R8_SSCALED = 33,
        VK_FORMAT_B8G8R8_UINT = 34,
        VK_FORMAT_B8G8R8_SINT = 35,
        VK_FORMAT_B8G8R8_SRGB = 36,
        VK_FORMAT_R8G8B8A8_UNORM = 37,
        VK_FORMAT_R8G8B8A8_SNORM = 38,
        VK_FORMAT_R8G8B8A8_USCALED = 39,
        VK_FORMAT_R8G8B8A8_SSCALED = 40,
        VK_FORMAT_R8G8B8A8_UINT = 41,
        VK_FORMAT_R8G8B8A8_SINT = 42,
        VK_FORMAT_R8G8B8A8_SRGB = 43,
        VK_FORMAT_B8G8R8A8_UNORM = 44,
        VK_FORMAT_B8G8R8A8_SNORM = 45,
        VK_FORMAT_B8G8R8A8_USCALED = 46,
        VK_FORMAT_B8G8R8A8_SSCALED = 47,
        VK_FORMAT_B8G8R8A8_UINT = 48,
        VK_FORMAT_B8G8R8A8_SINT = 49,
        VK_FORMAT_B8G8R8A8_SRGB = 50,
        VK_FORMAT_A8B8G8R8_UNORM_PACK32 = 51,
        VK_FORMAT_A8B8G8R8_SNORM_PACK32 = 52,
        VK_FORMAT_A8B8G8R8_USCALED_PACK32 = 53,
        VK_FORMAT_A8B8G8R8_SSCALED_PACK32 = 54,
        VK_FORMAT_A8B8G8R8_UINT_PACK32 = 55,
        VK_FORMAT_A8B8G8R8_SINT_PACK32 = 56,
        VK_FORMAT_A8B8G8R8_SRGB_PACK32 = 57,
        VK_FORMAT_A2R10G10B10_UNORM_PACK32 = 58,
        VK_FORMAT_A2R10G10B10_SNORM_PACK32 = 59,
        VK_FORMAT_A2R10G10B10_USCALED_PACK32 = 60,
        VK_FORMAT_A2R10G10B10_SSCALED_PACK32 = 61,
        VK_FORMAT_A2R10G10B10_UINT_PACK32 = 62,
        VK_FORMAT_A2R10G10B10_SINT_PACK32 = 63,
        VK_FORMAT_A2B10G10R10_UNORM_PACK32 = 64,
        VK_FORMAT_A2B10G10R10_SNORM_PACK32 = 65,
        VK_FORMAT_A2B10G10R10_USCALED_PACK32 = 66,
        VK_FORMAT_A2B10G10R10_SSCALED_PACK32 = 67,
        VK_FORMAT_A2B10G10R10_UINT_PACK32 = 68,
        VK_FORMAT_A2B10G10R10_SINT_PACK32 = 69,
        VK_FORMAT_R16_UNORM = 70,
        VK_FORMAT_R16_SNORM = 71,
        VK_FORMAT_R16_USCALED = 72,
        VK_FORMAT_R16_SSCALED = 73,
        VK_FORMAT_R16_UINT = 74,
        VK_FORMAT_R16_SINT = 75,
        VK_FORMAT_R16_SFLOAT = 76,
        VK_FORMAT_R16G16_UNORM = 77,
        VK_FORMAT_R16G16_SNORM = 78,
        VK_FORMAT_R16G16_USCALED = 79,
        VK_FORMAT_R16G16_SSCALED = 80,
        VK_FORMAT_R16G16_UINT = 81,
        VK_FORMAT_R16G16_SINT = 82,
        VK_FORMAT_R16G16_SFLOAT = 83,
        VK_FORMAT_R16G16B16_UNORM = 84,
        VK_FORMAT_R16G16B16_SNORM = 85,
        VK_FORMAT_R16G16B16_USCALED = 86,
        VK_FORMAT_R16G16B16_SSCALED = 87,
        VK_FORMAT_R16G16B16_UINT = 88,
        VK_FORMAT_R16G16B16_SINT = 89,
        VK_FORMAT_R16G16B16_SFLOAT = 90,
        VK_FORMAT_R16G16B16A16_UNORM = 91,
        VK_FORMAT_R16G16B16A16_SNORM = 92,
        VK_FORMAT_R16G16B16A16_USCALED = 93,
        VK_FORMAT_R16G16B16A16_SSCALED = 94,
        VK_FORMAT_R16G16B16A16_UINT = 95,
        VK_FORMAT_R16G16B16A16_SINT = 96,
        VK_FORMAT_R16G16B16A16_SFLOAT = 97,
        VK_FORMAT_R32_UINT = 98,
        VK_FORMAT_R32_SINT = 99,
        VK_FORMAT_R32_SFLOAT = 100,
        VK_FORMAT_R32G32_UINT = 101,
        VK_FORMAT_R32G32_SINT = 102,
        VK_FORMAT_R32G32_SFLOAT = 103,
        VK_FORMAT_R32G32B32_UINT = 104,
        VK_FORMAT_R32G32B32_SINT = 105,
        VK_FORMAT_R32G32B32_SFLOAT = 106,
        VK_FORMAT_R32G32B32A32_UINT = 107,
        VK_FORMAT_R32G32B32A32_SINT = 108,
        VK_FORMAT_R32G32B32A32_SFLOAT = 109,
        VK_FORMAT_R64_UINT = 110,
        VK_FORMAT_R64_SINT = 111,
        VK_FORMAT_R64_SFLOAT = 112,
        VK_FORMAT_R64G64_UINT = 113,
        VK_FORMAT_R64G64_SINT = 114,
        VK_FORMAT_R64G64_SFLOAT = 115,
        VK_FORMAT_R64G64B64_UINT = 116,
        VK_FORMAT_R64G64B64_SINT = 117,
        VK_FORMAT_R64G64B64_SFLOAT = 118,
        VK_FORMAT_R64G64B64A64_UINT = 119,
        VK_FORMAT_R64G64B64A64_SINT = 120,
        VK_FORMAT_R64G64B64A64_SFLOAT = 121,
        VK_FORMAT_B10G11R11_UFLOAT_PACK32 = 122,
        VK_FORMAT_E5B9G9R9_UFLOAT_PACK32 = 123,
        VK_FORMAT_D16_UNORM = 124,
        VK_FORMAT_X8_D24_UNORM_PACK32 = 125,
        VK_FORMAT_D32_SFLOAT = 126,
        VK_FORMAT_S8_UINT = 127,
        VK_FORMAT_D16_UNORM_S8_UINT = 128,
        VK_FORMAT_D24_UNORM_S8_UINT = 129,
        VK_FORMAT_D32_SFLOAT_S8_UINT = 130,
        VK_FORMAT_BC1_RGB_UNORM_BLOCK = 131,
        VK_FORMAT_BC1_RGB_SRGB_BLOCK = 132,
        VK_FORMAT_BC1_RGBA_UNORM_BLOCK = 133,
        VK_FORMAT_BC1_RGBA_SRGB_BLOCK = 134,
        VK_FORMAT_BC2_UNORM_BLOCK = 135,
        VK_FORMAT_BC2_SRGB_BLOCK = 136,
        VK_FORMAT_BC3_UNORM_BLOCK = 137,
        VK_FORMAT_BC3_SRGB_BLOCK = 138,
        VK_FORMAT_BC4_UNORM_BLOCK = 139,
        VK_FORMAT_BC4_SNORM_BLOCK = 140,
        VK_FORMAT_BC5_UNORM_BLOCK = 141,
        VK_FORMAT_BC5_SNORM_BLOCK = 142,
        VK_FORMAT_BC6H_UFLOAT_BLOCK = 143,
        VK_FORMAT_BC6H_SFLOAT_BLOCK = 144,
        VK_FORMAT_BC7_UNORM_BLOCK = 145,
        VK_FORMAT_BC7_SRGB_BLOCK = 146,
        VK_FORMAT_ETC2_R8G8B8_UNORM_BLOCK = 147,
        VK_FORMAT_ETC2_R8G8B8_SRGB_BLOCK = 148,
        VK_FORMAT_ETC2_R8G8B8A1_UNORM_BLOCK = 149,
        VK_FORMAT_ETC2_R8G8B8A1_SRGB_BLOCK = 150,
        VK_FORMAT_ETC2_R8G8B8A8_UNORM_BLOCK = 151,
        VK_FORMAT_ETC2_R8G8B8A8_SRGB_BLOCK = 152,
        VK_FORMAT_EAC_R11_UNORM_BLOCK = 153,
        VK_FORMAT_EAC_R11_SNORM_BLOCK = 154,
        VK_FORMAT_EAC_R11G11_UNORM_BLOCK = 155,
        VK_FORMAT_EAC_R11G11_SNORM_BLOCK = 156,
        VK_FORMAT_ASTC_4x4_UNORM_BLOCK = 157,
        VK_FORMAT_ASTC_4x4_SRGB_BLOCK = 158,
        VK_FORMAT_ASTC_5x4_UNORM_BLOCK = 159,
        VK_FORMAT_ASTC_5x4_SRGB_BLOCK = 160,
        VK_FORMAT_ASTC_5x5_UNORM_BLOCK = 161,
        VK_FORMAT_ASTC_5x5_SRGB_BLOCK = 162,
        VK_FORMAT_ASTC_6x5_UNORM_BLOCK = 163,
        VK_FORMAT_ASTC_6x5_SRGB_BLOCK = 164,
        VK_FORMAT_ASTC_6x6_UNORM_BLOCK = 165,
        VK_FORMAT_ASTC_6x6_SRGB_BLOCK = 166,
        VK_FORMAT_ASTC_8x5_UNORM_BLOCK = 167,
        VK_FORMAT_ASTC_8x5_SRGB_BLOCK = 168,
        VK_FORMAT_ASTC_8x6_UNORM_BLOCK = 169,
        VK_FORMAT_ASTC_8x6_SRGB_BLOCK = 170,
        VK_FORMAT_ASTC_8x8_UNORM_BLOCK = 171,
        VK_FORMAT_ASTC_8x8_SRGB_BLOCK = 172,
        VK_FORMAT_ASTC_10x5_UNORM_BLOCK = 173,
        VK_FORMAT_ASTC_10x5_SRGB_BLOCK = 174,
        VK_FORMAT_ASTC_10x6_UNORM_BLOCK = 175,
        VK_FORMAT_ASTC_10x6_SRGB_BLOCK = 176,
        VK_FORMAT_ASTC_10x8_UNORM_BLOCK = 177,
        VK_FORMAT_ASTC_10x8_SRGB_BLOCK = 178,
        VK_FORMAT_ASTC_10x10_UNORM_BLOCK = 179,
        VK_FORMAT_ASTC_10x10_SRGB_BLOCK = 180,
        VK_FORMAT_ASTC_12x10_UNORM_BLOCK = 181,
        VK_FORMAT_ASTC_12x10_SRGB_BLOCK = 182,
        VK_FORMAT_ASTC_12x12_UNORM_BLOCK = 183,
        VK_FORMAT_ASTC_12x12_SRGB_BLOCK = 184,
        VK_FORMAT_G8B8G8R8_422_UNORM = 1000156000,
        VK_FORMAT_B8G8R8G8_422_UNORM = 1000156001,
        VK_FORMAT_G8_B8_R8_3PLANE_420_UNORM = 1000156002,
        VK_FORMAT_G8_B8R8_2PLANE_420_UNORM = 1000156003,
        VK_FORMAT_G8_B8_R8_3PLANE_422_UNORM = 1000156004,
        VK_FORMAT_G8_B8R8_2PLANE_422_UNORM = 1000156005,
        VK_FORMAT_G8_B8_R8_3PLANE_444_UNORM = 1000156006,
        VK_FORMAT_R10X6_UNORM_PACK16 = 1000156007,
        VK_FORMAT_R10X6G10X6_UNORM_2PACK16 = 1000156008,
        VK_FORMAT_R10X6G10X6B10X6A10X6_UNORM_4PACK16 = 1000156009,
        VK_FORMAT_G10X6B10X6G10X6R10X6_422_UNORM_4PACK16 = 1000156010,
        VK_FORMAT_B10X6G10X6R10X6G10X6_422_UNORM_4PACK16 = 1000156011,
        VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_420_UNORM_3PACK16 = 1000156012,
        VK_FORMAT_G10X6_B10X6R10X6_2PLANE_420_UNORM_3PACK16 = 1000156013,
        VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_422_UNORM_3PACK16 = 1000156014,
        VK_FORMAT_G10X6_B10X6R10X6_2PLANE_422_UNORM_3PACK16 = 1000156015,
        VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_444_UNORM_3PACK16 = 1000156016,
        VK_FORMAT_R12X4_UNORM_PACK16 = 1000156017,
        VK_FORMAT_R12X4G12X4_UNORM_2PACK16 = 1000156018,
        VK_FORMAT_R12X4G12X4B12X4A12X4_UNORM_4PACK16 = 1000156019,
        VK_FORMAT_G12X4B12X4G12X4R12X4_422_UNORM_4PACK16 = 1000156020,
        VK_FORMAT_B12X4G12X4R12X4G12X4_422_UNORM_4PACK16 = 1000156021,
        VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_420_UNORM_3PACK16 = 1000156022,
        VK_FORMAT_G12X4_B12X4R12X4_2PLANE_420_UNORM_3PACK16 = 1000156023,
        VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_422_UNORM_3PACK16 = 1000156024,
        VK_FORMAT_G12X4_B12X4R12X4_2PLANE_422_UNORM_3PACK16 = 1000156025,
        VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_444_UNORM_3PACK16 = 1000156026,
        VK_FORMAT_G16B16G16R16_422_UNORM = 1000156027,
        VK_FORMAT_B16G16R16G16_422_UNORM = 1000156028,
        VK_FORMAT_G16_B16_R16_3PLANE_420_UNORM = 1000156029,
        VK_FORMAT_G16_B16R16_2PLANE_420_UNORM = 1000156030,
        VK_FORMAT_G16_B16_R16_3PLANE_422_UNORM = 1000156031,
        VK_FORMAT_G16_B16R16_2PLANE_422_UNORM = 1000156032,
        VK_FORMAT_G16_B16_R16_3PLANE_444_UNORM = 1000156033,
        VK_FORMAT_PVRTC1_2BPP_UNORM_BLOCK_IMG = 1000054000,
        VK_FORMAT_PVRTC1_4BPP_UNORM_BLOCK_IMG = 1000054001,
        VK_FORMAT_PVRTC2_2BPP_UNORM_BLOCK_IMG = 1000054002,
        VK_FORMAT_PVRTC2_4BPP_UNORM_BLOCK_IMG = 1000054003,
        VK_FORMAT_PVRTC1_2BPP_SRGB_BLOCK_IMG = 1000054004,
        VK_FORMAT_PVRTC1_4BPP_SRGB_BLOCK_IMG = 1000054005,
        VK_FORMAT_PVRTC2_2BPP_SRGB_BLOCK_IMG = 1000054006,
        VK_FORMAT_PVRTC2_4BPP_SRGB_BLOCK_IMG = 1000054007,
        VK_FORMAT_ASTC_4x4_SFLOAT_BLOCK_EXT = 1000066000,
        VK_FORMAT_ASTC_5x4_SFLOAT_BLOCK_EXT = 1000066001,
        VK_FORMAT_ASTC_5x5_SFLOAT_BLOCK_EXT = 1000066002,
        VK_FORMAT_ASTC_6x5_SFLOAT_BLOCK_EXT = 1000066003,
        VK_FORMAT_ASTC_6x6_SFLOAT_BLOCK_EXT = 1000066004,
        VK_FORMAT_ASTC_8x5_SFLOAT_BLOCK_EXT = 1000066005,
        VK_FORMAT_ASTC_8x6_SFLOAT_BLOCK_EXT = 1000066006,
        VK_FORMAT_ASTC_8x8_SFLOAT_BLOCK_EXT = 1000066007,
        VK_FORMAT_ASTC_10x5_SFLOAT_BLOCK_EXT = 1000066008,
        VK_FORMAT_ASTC_10x6_SFLOAT_BLOCK_EXT = 1000066009,
        VK_FORMAT_ASTC_10x8_SFLOAT_BLOCK_EXT = 1000066010,
        VK_FORMAT_ASTC_10x10_SFLOAT_BLOCK_EXT = 1000066011,
        VK_FORMAT_ASTC_12x10_SFLOAT_BLOCK_EXT = 1000066012,
        VK_FORMAT_ASTC_12x12_SFLOAT_BLOCK_EXT = 1000066013,
        VK_FORMAT_G8B8G8R8_422_UNORM_KHR = VK_FORMAT_G8B8G8R8_422_UNORM,
        VK_FORMAT_B8G8R8G8_422_UNORM_KHR = VK_FORMAT_B8G8R8G8_422_UNORM,
        VK_FORMAT_G8_B8_R8_3PLANE_420_UNORM_KHR = VK_FORMAT_G8_B8_R8_3PLANE_420_UNORM,
        VK_FORMAT_G8_B8R8_2PLANE_420_UNORM_KHR = VK_FORMAT_G8_B8R8_2PLANE_420_UNORM,
        VK_FORMAT_G8_B8_R8_3PLANE_422_UNORM_KHR = VK_FORMAT_G8_B8_R8_3PLANE_422_UNORM,
        VK_FORMAT_G8_B8R8_2PLANE_422_UNORM_KHR = VK_FORMAT_G8_B8R8_2PLANE_422_UNORM,
        VK_FORMAT_G8_B8_R8_3PLANE_444_UNORM_KHR = VK_FORMAT_G8_B8_R8_3PLANE_444_UNORM,
        VK_FORMAT_R10X6_UNORM_PACK16_KHR = VK_FORMAT_R10X6_UNORM_PACK16,
        VK_FORMAT_R10X6G10X6_UNORM_2PACK16_KHR = VK_FORMAT_R10X6G10X6_UNORM_2PACK16,
        VK_FORMAT_R10X6G10X6B10X6A10X6_UNORM_4PACK16_KHR = VK_FORMAT_R10X6G10X6B10X6A10X6_UNORM_4PACK16,
        VK_FORMAT_G10X6B10X6G10X6R10X6_422_UNORM_4PACK16_KHR = VK_FORMAT_G10X6B10X6G10X6R10X6_422_UNORM_4PACK16,
        VK_FORMAT_B10X6G10X6R10X6G10X6_422_UNORM_4PACK16_KHR = VK_FORMAT_B10X6G10X6R10X6G10X6_422_UNORM_4PACK16,
        VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_420_UNORM_3PACK16_KHR = VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_420_UNORM_3PACK16,
        VK_FORMAT_G10X6_B10X6R10X6_2PLANE_420_UNORM_3PACK16_KHR = VK_FORMAT_G10X6_B10X6R10X6_2PLANE_420_UNORM_3PACK16,
        VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_422_UNORM_3PACK16_KHR = VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_422_UNORM_3PACK16,
        VK_FORMAT_G10X6_B10X6R10X6_2PLANE_422_UNORM_3PACK16_KHR = VK_FORMAT_G10X6_B10X6R10X6_2PLANE_422_UNORM_3PACK16,
        VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_444_UNORM_3PACK16_KHR = VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_444_UNORM_3PACK16,
        VK_FORMAT_R12X4_UNORM_PACK16_KHR = VK_FORMAT_R12X4_UNORM_PACK16,
        VK_FORMAT_R12X4G12X4_UNORM_2PACK16_KHR = VK_FORMAT_R12X4G12X4_UNORM_2PACK16,
        VK_FORMAT_R12X4G12X4B12X4A12X4_UNORM_4PACK16_KHR = VK_FORMAT_R12X4G12X4B12X4A12X4_UNORM_4PACK16,
        VK_FORMAT_G12X4B12X4G12X4R12X4_422_UNORM_4PACK16_KHR = VK_FORMAT_G12X4B12X4G12X4R12X4_422_UNORM_4PACK16,
        VK_FORMAT_B12X4G12X4R12X4G12X4_422_UNORM_4PACK16_KHR = VK_FORMAT_B12X4G12X4R12X4G12X4_422_UNORM_4PACK16,
        VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_420_UNORM_3PACK16_KHR = VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_420_UNORM_3PACK16,
        VK_FORMAT_G12X4_B12X4R12X4_2PLANE_420_UNORM_3PACK16_KHR = VK_FORMAT_G12X4_B12X4R12X4_2PLANE_420_UNORM_3PACK16,
        VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_422_UNORM_3PACK16_KHR = VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_422_UNORM_3PACK16,
        VK_FORMAT_G12X4_B12X4R12X4_2PLANE_422_UNORM_3PACK16_KHR = VK_FORMAT_G12X4_B12X4R12X4_2PLANE_422_UNORM_3PACK16,
        VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_444_UNORM_3PACK16_KHR = VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_444_UNORM_3PACK16,
        VK_FORMAT_G16B16G16R16_422_UNORM_KHR = VK_FORMAT_G16B16G16R16_422_UNORM,
        VK_FORMAT_B16G16R16G16_422_UNORM_KHR = VK_FORMAT_B16G16R16G16_422_UNORM,
        VK_FORMAT_G16_B16_R16_3PLANE_420_UNORM_KHR = VK_FORMAT_G16_B16_R16_3PLANE_420_UNORM,
        VK_FORMAT_G16_B16R16_2PLANE_420_UNORM_KHR = VK_FORMAT_G16_B16R16_2PLANE_420_UNORM,
        VK_FORMAT_G16_B16_R16_3PLANE_422_UNORM_KHR = VK_FORMAT_G16_B16_R16_3PLANE_422_UNORM,
        VK_FORMAT_G16_B16R16_2PLANE_422_UNORM_KHR = VK_FORMAT_G16_B16R16_2PLANE_422_UNORM,
        VK_FORMAT_G16_B16_R16_3PLANE_444_UNORM_KHR = VK_FORMAT_G16_B16_R16_3PLANE_444_UNORM,
        VK_FORMAT_MAX_ENUM = 0x7FFFFFFF
    } VkFormat;

- `VK_FORMAT_UNDEFINED` specifies that the format is not specified.

- `VK_FORMAT_R4G4_UNORM_PACK8` specifies a two-component, 8-bit packed unsigned normalized format that has a 4-bit R component in bits 4..7, and a 4-bit G component in bits 0..3.

- `VK_FORMAT_R4G4B4A4_UNORM_PACK16` specifies a four-component, 16-bit packed unsigned normalized format that has a 4-bit R component in bits 12..15, a 4-bit G component in bits 8..11, a 4-bit B component in bits 4..7, and a 4-bit A component in bits 0..3.

- `VK_FORMAT_B4G4R4A4_UNORM_PACK16` specifies a four-component, 16-bit packed unsigned normalized format that has a 4-bit B component in bits 12..15, a 4-bit G component in bits 8..11, a 4-bit R component in bits 4..7, and a 4-bit A component in bits 0..3.

- `VK_FORMAT_R5G6B5_UNORM_PACK16` specifies a three-component, 16-bit packed unsigned normalized format that has a 5-bit R component in bits 11..15, a 6-bit G component in bits 5..10, and a 5-bit B component in bits 0..4.

- `VK_FORMAT_B5G6R5_UNORM_PACK16` specifies a three-component, 16-bit packed unsigned normalized format that has a 5-bit B component in bits 11..15, a 6-bit G component in bits 5..10, and a 5-bit R component in bits 0..4.

- `VK_FORMAT_R5G5B5A1_UNORM_PACK16` specifies a four-component, 16-bit packed unsigned normalized format that has a 5-bit R component in bits 11..15, a 5-bit G component in bits 6..10, a 5-bit B component in bits 1..5, and a 1-bit A component in bit 0.

- `VK_FORMAT_B5G5R5A1_UNORM_PACK16` specifies a four-component, 16-bit packed unsigned normalized format that has a 5-bit B component in bits 11..15, a 5-bit G component in bits 6..10, a 5-bit R component in bits 1..5, and a 1-bit A component in bit 0.

- `VK_FORMAT_A1R5G5B5_UNORM_PACK16` specifies a four-component, 16-bit packed unsigned normalized format that has a 1-bit A component in bit 15, a 5-bit R component in bits 10..14, a 5-bit G component in bits 5..9, and a 5-bit B component in bits 0..4.

- `VK_FORMAT_R8_UNORM` specifies a one-component, 8-bit unsigned normalized format that has a single 8-bit R component.

- `VK_FORMAT_R8_SNORM` specifies a one-component, 8-bit signed normalized format that has a single 8-bit R component.

- `VK_FORMAT_R8_USCALED` specifies a one-component, 8-bit unsigned scaled integer format that has a single 8-bit R component.

- `VK_FORMAT_R8_SSCALED` specifies a one-component, 8-bit signed scaled integer format that has a single 8-bit R component.

- `VK_FORMAT_R8_UINT` specifies a one-component, 8-bit unsigned integer format that has a single 8-bit R component.

- `VK_FORMAT_R8_SINT` specifies a one-component, 8-bit signed integer format that has a single 8-bit R component.

- `VK_FORMAT_R8_SRGB` specifies a one-component, 8-bit unsigned normalized format that has a single 8-bit R component stored with sRGB nonlinear encoding.

- `VK_FORMAT_R8G8_UNORM` specifies a two-component, 16-bit unsigned normalized format that has an 8-bit R component in byte 0, and an 8-bit G component in byte 1.

- `VK_FORMAT_R8G8_SNORM` specifies a two-component, 16-bit signed normalized format that has an 8-bit R component in byte 0, and an 8-bit G component in byte 1.

- `VK_FORMAT_R8G8_USCALED` specifies a two-component, 16-bit unsigned scaled integer format that has an 8-bit R component in byte 0, and an 8-bit G component in byte 1.

- `VK_FORMAT_R8G8_SSCALED` specifies a two-component, 16-bit signed scaled integer format that has an 8-bit R component in byte 0, and an 8-bit G component in byte 1.

- `VK_FORMAT_R8G8_UINT` specifies a two-component, 16-bit unsigned integer format that has an 8-bit R component in byte 0, and an 8-bit G component in byte 1.

- `VK_FORMAT_R8G8_SINT` specifies a two-component, 16-bit signed integer format that has an 8-bit R component in byte 0, and an 8-bit G component in byte 1.

- `VK_FORMAT_R8G8_SRGB` specifies a two-component, 16-bit unsigned normalized format that has an 8-bit R component stored with sRGB nonlinear encoding in byte 0, and an 8-bit G component stored with sRGB nonlinear encoding in byte 1.

- `VK_FORMAT_R8G8B8_UNORM` specifies a three-component, 24-bit unsigned normalized format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, and an 8-bit B component in byte 2.

- `VK_FORMAT_R8G8B8_SNORM` specifies a three-component, 24-bit signed normalized format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, and an 8-bit B component in byte 2.

- `VK_FORMAT_R8G8B8_USCALED` specifies a three-component, 24-bit unsigned scaled format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, and an 8-bit B component in byte 2.

- `VK_FORMAT_R8G8B8_SSCALED` specifies a three-component, 24-bit signed scaled format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, and an 8-bit B component in byte 2.

- `VK_FORMAT_R8G8B8_UINT` specifies a three-component, 24-bit unsigned integer format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, and an 8-bit B component in byte 2.

- `VK_FORMAT_R8G8B8_SINT` specifies a three-component, 24-bit signed integer format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, and an 8-bit B component in byte 2.

- `VK_FORMAT_R8G8B8_SRGB` specifies a three-component, 24-bit unsigned normalized format that has an 8-bit R component stored with sRGB nonlinear encoding in byte 0, an 8-bit G component stored with sRGB nonlinear encoding in byte 1, and an 8-bit B component stored with sRGB nonlinear encoding in byte 2.

- `VK_FORMAT_B8G8R8_UNORM` specifies a three-component, 24-bit unsigned normalized format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, and an 8-bit R component in byte 2.

- `VK_FORMAT_B8G8R8_SNORM` specifies a three-component, 24-bit signed normalized format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, and an 8-bit R component in byte 2.

- `VK_FORMAT_B8G8R8_USCALED` specifies a three-component, 24-bit unsigned scaled format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, and an 8-bit R component in byte 2.

- `VK_FORMAT_B8G8R8_SSCALED` specifies a three-component, 24-bit signed scaled format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, and an 8-bit R component in byte 2.

- `VK_FORMAT_B8G8R8_UINT` specifies a three-component, 24-bit unsigned integer format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, and an 8-bit R component in byte 2.

- `VK_FORMAT_B8G8R8_SINT` specifies a three-component, 24-bit signed integer format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, and an 8-bit R component in byte 2.

- `VK_FORMAT_B8G8R8_SRGB` specifies a three-component, 24-bit unsigned normalized format that has an 8-bit B component stored with sRGB nonlinear encoding in byte 0, an 8-bit G component stored with sRGB nonlinear encoding in byte 1, and an 8-bit R component stored with sRGB nonlinear encoding in byte 2.

- `VK_FORMAT_R8G8B8A8_UNORM` specifies a four-component, 32-bit unsigned normalized format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, an 8-bit B component in byte 2, and an 8-bit A component in byte 3.

- `VK_FORMAT_R8G8B8A8_SNORM` specifies a four-component, 32-bit signed normalized format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, an 8-bit B component in byte 2, and an 8-bit A component in byte 3.

- `VK_FORMAT_R8G8B8A8_USCALED` specifies a four-component, 32-bit unsigned scaled format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, an 8-bit B component in byte 2, and an 8-bit A component in byte 3.

- `VK_FORMAT_R8G8B8A8_SSCALED` specifies a four-component, 32-bit signed scaled format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, an 8-bit B component in byte 2, and an 8-bit A component in byte 3.

- `VK_FORMAT_R8G8B8A8_UINT` specifies a four-component, 32-bit unsigned integer format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, an 8-bit B component in byte 2, and an 8-bit A component in byte 3.

- `VK_FORMAT_R8G8B8A8_SINT` specifies a four-component, 32-bit signed integer format that has an 8-bit R component in byte 0, an 8-bit G component in byte 1, an 8-bit B component in byte 2, and an 8-bit A component in byte 3.

- `VK_FORMAT_R8G8B8A8_SRGB` specifies a four-component, 32-bit unsigned normalized format that has an 8-bit R component stored with sRGB nonlinear encoding in byte 0, an 8-bit G component stored with sRGB nonlinear encoding in byte 1, an 8-bit B component stored with sRGB nonlinear encoding in byte 2, and an 8-bit A component in byte 3.

- `VK_FORMAT_B8G8R8A8_UNORM` specifies a four-component, 32-bit unsigned normalized format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, an 8-bit R component in byte 2, and an 8-bit A component in byte 3.

- `VK_FORMAT_B8G8R8A8_SNORM` specifies a four-component, 32-bit signed normalized format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, an 8-bit R component in byte 2, and an 8-bit A component in byte 3.

- `VK_FORMAT_B8G8R8A8_USCALED` specifies a four-component, 32-bit unsigned scaled format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, an 8-bit R component in byte 2, and an 8-bit A component in byte 3.

- `VK_FORMAT_B8G8R8A8_SSCALED` specifies a four-component, 32-bit signed scaled format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, an 8-bit R component in byte 2, and an 8-bit A component in byte 3.

- `VK_FORMAT_B8G8R8A8_UINT` specifies a four-component, 32-bit unsigned integer format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, an 8-bit R component in byte 2, and an 8-bit A component in byte 3.

- `VK_FORMAT_B8G8R8A8_SINT` specifies a four-component, 32-bit signed integer format that has an 8-bit B component in byte 0, an 8-bit G component in byte 1, an 8-bit R component in byte 2, and an 8-bit A component in byte 3.

- `VK_FORMAT_B8G8R8A8_SRGB` specifies a four-component, 32-bit unsigned normalized format that has an 8-bit B component stored with sRGB nonlinear encoding in byte 0, an 8-bit G component stored with sRGB nonlinear encoding in byte 1, an 8-bit R component stored with sRGB nonlinear encoding in byte 2, and an 8-bit A component in byte 3.

- `VK_FORMAT_A8B8G8R8_UNORM_PACK32` specifies a four-component, 32-bit packed unsigned normalized format that has an 8-bit A component in bits 24..31, an 8-bit B component in bits 16..23, an 8-bit G component in bits 8..15, and an 8-bit R component in bits 0..7.

- `VK_FORMAT_A8B8G8R8_SNORM_PACK32` specifies a four-component, 32-bit packed signed normalized format that has an 8-bit A component in bits 24..31, an 8-bit B component in bits 16..23, an 8-bit G component in bits 8..15, and an 8-bit R component in bits 0..7.

- `VK_FORMAT_A8B8G8R8_USCALED_PACK32` specifies a four-component, 32-bit packed unsigned scaled integer format that has an 8-bit A component in bits 24..31, an 8-bit B component in bits 16..23, an 8-bit G component in bits 8..15, and an 8-bit R component in bits 0..7.

- `VK_FORMAT_A8B8G8R8_SSCALED_PACK32` specifies a four-component, 32-bit packed signed scaled integer format that has an 8-bit A component in bits 24..31, an 8-bit B component in bits 16..23, an 8-bit G component in bits 8..15, and an 8-bit R component in bits 0..7.

- `VK_FORMAT_A8B8G8R8_UINT_PACK32` specifies a four-component, 32-bit packed unsigned integer format that has an 8-bit A component in bits 24..31, an 8-bit B component in bits 16..23, an 8-bit G component in bits 8..15, and an 8-bit R component in bits 0..7.

- `VK_FORMAT_A8B8G8R8_SINT_PACK32` specifies a four-component, 32-bit packed signed integer format that has an 8-bit A component in bits 24..31, an 8-bit B component in bits 16..23, an 8-bit G component in bits 8..15, and an 8-bit R component in bits 0..7.

- `VK_FORMAT_A8B8G8R8_SRGB_PACK32` specifies a four-component, 32-bit packed unsigned normalized format that has an 8-bit A component in bits 24..31, an 8-bit B component stored with sRGB nonlinear encoding in bits 16..23, an 8-bit G component stored with sRGB nonlinear encoding in bits 8..15, and an 8-bit R component stored with sRGB nonlinear encoding in bits 0..7.

- `VK_FORMAT_A2R10G10B10_UNORM_PACK32` specifies a four-component, 32-bit packed unsigned normalized format that has a 2-bit A component in bits 30..31, a 10-bit R component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit B component in bits 0..9.

- `VK_FORMAT_A2R10G10B10_SNORM_PACK32` specifies a four-component, 32-bit packed signed normalized format that has a 2-bit A component in bits 30..31, a 10-bit R component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit B component in bits 0..9.

- `VK_FORMAT_A2R10G10B10_USCALED_PACK32` specifies a four-component, 32-bit packed unsigned scaled integer format that has a 2-bit A component in bits 30..31, a 10-bit R component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit B component in bits 0..9.

- `VK_FORMAT_A2R10G10B10_SSCALED_PACK32` specifies a four-component, 32-bit packed signed scaled integer format that has a 2-bit A component in bits 30..31, a 10-bit R component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit B component in bits 0..9.

- `VK_FORMAT_A2R10G10B10_UINT_PACK32` specifies a four-component, 32-bit packed unsigned integer format that has a 2-bit A component in bits 30..31, a 10-bit R component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit B component in bits 0..9.

- `VK_FORMAT_A2R10G10B10_SINT_PACK32` specifies a four-component, 32-bit packed signed integer format that has a 2-bit A component in bits 30..31, a 10-bit R component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit B component in bits 0..9.

- `VK_FORMAT_A2B10G10R10_UNORM_PACK32` specifies a four-component, 32-bit packed unsigned normalized format that has a 2-bit A component in bits 30..31, a 10-bit B component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit R component in bits 0..9.

- `VK_FORMAT_A2B10G10R10_SNORM_PACK32` specifies a four-component, 32-bit packed signed normalized format that has a 2-bit A component in bits 30..31, a 10-bit B component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit R component in bits 0..9.

- `VK_FORMAT_A2B10G10R10_USCALED_PACK32` specifies a four-component, 32-bit packed unsigned scaled integer format that has a 2-bit A component in bits 30..31, a 10-bit B component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit R component in bits 0..9.

- `VK_FORMAT_A2B10G10R10_SSCALED_PACK32` specifies a four-component, 32-bit packed signed scaled integer format that has a 2-bit A component in bits 30..31, a 10-bit B component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit R component in bits 0..9.

- `VK_FORMAT_A2B10G10R10_UINT_PACK32` specifies a four-component, 32-bit packed unsigned integer format that has a 2-bit A component in bits 30..31, a 10-bit B component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit R component in bits 0..9.

- `VK_FORMAT_A2B10G10R10_SINT_PACK32` specifies a four-component, 32-bit packed signed integer format that has a 2-bit A component in bits 30..31, a 10-bit B component in bits 20..29, a 10-bit G component in bits 10..19, and a 10-bit R component in bits 0..9.

- `VK_FORMAT_R16_UNORM` specifies a one-component, 16-bit unsigned normalized format that has a single 16-bit R component.

- `VK_FORMAT_R16_SNORM` specifies a one-component, 16-bit signed normalized format that has a single 16-bit R component.

- `VK_FORMAT_R16_USCALED` specifies a one-component, 16-bit unsigned scaled integer format that has a single 16-bit R component.

- `VK_FORMAT_R16_SSCALED` specifies a one-component, 16-bit signed scaled integer format that has a single 16-bit R component.

- `VK_FORMAT_R16_UINT` specifies a one-component, 16-bit unsigned integer format that has a single 16-bit R component.

- `VK_FORMAT_R16_SINT` specifies a one-component, 16-bit signed integer format that has a single 16-bit R component.

- `VK_FORMAT_R16_SFLOAT` specifies a one-component, 16-bit signed floating-point format that has a single 16-bit R component.

- `VK_FORMAT_R16G16_UNORM` specifies a two-component, 32-bit unsigned normalized format that has a 16-bit R component in bytes 0..1, and a 16-bit G component in bytes 2..3.

- `VK_FORMAT_R16G16_SNORM` specifies a two-component, 32-bit signed normalized format that has a 16-bit R component in bytes 0..1, and a 16-bit G component in bytes 2..3.

- `VK_FORMAT_R16G16_USCALED` specifies a two-component, 32-bit unsigned scaled integer format that has a 16-bit R component in bytes 0..1, and a 16-bit G component in bytes 2..3.

- `VK_FORMAT_R16G16_SSCALED` specifies a two-component, 32-bit signed scaled integer format that has a 16-bit R component in bytes 0..1, and a 16-bit G component in bytes 2..3.

- `VK_FORMAT_R16G16_UINT` specifies a two-component, 32-bit unsigned integer format that has a 16-bit R component in bytes 0..1, and a 16-bit G component in bytes 2..3.

- `VK_FORMAT_R16G16_SINT` specifies a two-component, 32-bit signed integer format that has a 16-bit R component in bytes 0..1, and a 16-bit G component in bytes 2..3.

- `VK_FORMAT_R16G16_SFLOAT` specifies a two-component, 32-bit signed floating-point format that has a 16-bit R component in bytes 0..1, and a 16-bit G component in bytes 2..3.

- `VK_FORMAT_R16G16B16_UNORM` specifies a three-component, 48-bit unsigned normalized format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, and a 16-bit B component in bytes 4..5.

- `VK_FORMAT_R16G16B16_SNORM` specifies a three-component, 48-bit signed normalized format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, and a 16-bit B component in bytes 4..5.

- `VK_FORMAT_R16G16B16_USCALED` specifies a three-component, 48-bit unsigned scaled integer format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, and a 16-bit B component in bytes 4..5.

- `VK_FORMAT_R16G16B16_SSCALED` specifies a three-component, 48-bit signed scaled integer format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, and a 16-bit B component in bytes 4..5.

- `VK_FORMAT_R16G16B16_UINT` specifies a three-component, 48-bit unsigned integer format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, and a 16-bit B component in bytes 4..5.

- `VK_FORMAT_R16G16B16_SINT` specifies a three-component, 48-bit signed integer format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, and a 16-bit B component in bytes 4..5.

- `VK_FORMAT_R16G16B16_SFLOAT` specifies a three-component, 48-bit signed floating-point format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, and a 16-bit B component in bytes 4..5.

- `VK_FORMAT_R16G16B16A16_UNORM` specifies a four-component, 64-bit unsigned normalized format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, a 16-bit B component in bytes 4..5, and a 16-bit A component in bytes 6..7.

- `VK_FORMAT_R16G16B16A16_SNORM` specifies a four-component, 64-bit signed normalized format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, a 16-bit B component in bytes 4..5, and a 16-bit A component in bytes 6..7.

- `VK_FORMAT_R16G16B16A16_USCALED` specifies a four-component, 64-bit unsigned scaled integer format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, a 16-bit B component in bytes 4..5, and a 16-bit A component in bytes 6..7.

- `VK_FORMAT_R16G16B16A16_SSCALED` specifies a four-component, 64-bit signed scaled integer format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, a 16-bit B component in bytes 4..5, and a 16-bit A component in bytes 6..7.

- `VK_FORMAT_R16G16B16A16_UINT` specifies a four-component, 64-bit unsigned integer format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, a 16-bit B component in bytes 4..5, and a 16-bit A component in bytes 6..7.

- `VK_FORMAT_R16G16B16A16_SINT` specifies a four-component, 64-bit signed integer format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, a 16-bit B component in bytes 4..5, and a 16-bit A component in bytes 6..7.

- `VK_FORMAT_R16G16B16A16_SFLOAT` specifies a four-component, 64-bit signed floating-point format that has a 16-bit R component in bytes 0..1, a 16-bit G component in bytes 2..3, a 16-bit B component in bytes 4..5, and a 16-bit A component in bytes 6..7.

- `VK_FORMAT_R32_UINT` specifies a one-component, 32-bit unsigned integer format that has a single 32-bit R component.

- `VK_FORMAT_R32_SINT` specifies a one-component, 32-bit signed integer format that has a single 32-bit R component.

- `VK_FORMAT_R32_SFLOAT` specifies a one-component, 32-bit signed floating-point format that has a single 32-bit R component.

- `VK_FORMAT_R32G32_UINT` specifies a two-component, 64-bit unsigned integer format that has a 32-bit R component in bytes 0..3, and a 32-bit G component in bytes 4..7.

- `VK_FORMAT_R32G32_SINT` specifies a two-component, 64-bit signed integer format that has a 32-bit R component in bytes 0..3, and a 32-bit G component in bytes 4..7.

- `VK_FORMAT_R32G32_SFLOAT` specifies a two-component, 64-bit signed floating-point format that has a 32-bit R component in bytes 0..3, and a 32-bit G component in bytes 4..7.

- `VK_FORMAT_R32G32B32_UINT` specifies a three-component, 96-bit unsigned integer format that has a 32-bit R component in bytes 0..3, a 32-bit G component in bytes 4..7, and a 32-bit B component in bytes 8..11.

- `VK_FORMAT_R32G32B32_SINT` specifies a three-component, 96-bit signed integer format that has a 32-bit R component in bytes 0..3, a 32-bit G component in bytes 4..7, and a 32-bit B component in bytes 8..11.

- `VK_FORMAT_R32G32B32_SFLOAT` specifies a three-component, 96-bit signed floating-point format that has a 32-bit R component in bytes 0..3, a 32-bit G component in bytes 4..7, and a 32-bit B component in bytes 8..11.

- `VK_FORMAT_R32G32B32A32_UINT` specifies a four-component, 128-bit unsigned integer format that has a 32-bit R component in bytes 0..3, a 32-bit G component in bytes 4..7, a 32-bit B component in bytes 8..11, and a 32-bit A component in bytes 12..15.

- `VK_FORMAT_R32G32B32A32_SINT` specifies a four-component, 128-bit signed integer format that has a 32-bit R component in bytes 0..3, a 32-bit G component in bytes 4..7, a 32-bit B component in bytes 8..11, and a 32-bit A component in bytes 12..15.

- `VK_FORMAT_R32G32B32A32_SFLOAT` specifies a four-component, 128-bit signed floating-point format that has a 32-bit R component in bytes 0..3, a 32-bit G component in bytes 4..7, a 32-bit B component in bytes 8..11, and a 32-bit A component in bytes 12..15.

- `VK_FORMAT_R64_UINT` specifies a one-component, 64-bit unsigned integer format that has a single 64-bit R component.

- `VK_FORMAT_R64_SINT` specifies a one-component, 64-bit signed integer format that has a single 64-bit R component.

- `VK_FORMAT_R64_SFLOAT` specifies a one-component, 64-bit signed floating-point format that has a single 64-bit R component.

- `VK_FORMAT_R64G64_UINT` specifies a two-component, 128-bit unsigned integer format that has a 64-bit R component in bytes 0..7, and a 64-bit G component in bytes 8..15.

- `VK_FORMAT_R64G64_SINT` specifies a two-component, 128-bit signed integer format that has a 64-bit R component in bytes 0..7, and a 64-bit G component in bytes 8..15.

- `VK_FORMAT_R64G64_SFLOAT` specifies a two-component, 128-bit signed floating-point format that has a 64-bit R component in bytes 0..7, and a 64-bit G component in bytes 8..15.

- `VK_FORMAT_R64G64B64_UINT` specifies a three-component, 192-bit unsigned integer format that has a 64-bit R component in bytes 0..7, a 64-bit G component in bytes 8..15, and a 64-bit B component in bytes 16..23.

- `VK_FORMAT_R64G64B64_SINT` specifies a three-component, 192-bit signed integer format that has a 64-bit R component in bytes 0..7, a 64-bit G component in bytes 8..15, and a 64-bit B component in bytes 16..23.

- `VK_FORMAT_R64G64B64_SFLOAT` specifies a three-component, 192-bit signed floating-point format that has a 64-bit R component in bytes 0..7, a 64-bit G component in bytes 8..15, and a 64-bit B component in bytes 16..23.

- `VK_FORMAT_R64G64B64A64_UINT` specifies a four-component, 256-bit unsigned integer format that has a 64-bit R component in bytes 0..7, a 64-bit G component in bytes 8..15, a 64-bit B component in bytes 16..23, and a 64-bit A component in bytes 24..31.

- `VK_FORMAT_R64G64B64A64_SINT` specifies a four-component, 256-bit signed integer format that has a 64-bit R component in bytes 0..7, a 64-bit G component in bytes 8..15, a 64-bit B component in bytes 16..23, and a 64-bit A component in bytes 24..31.

- `VK_FORMAT_R64G64B64A64_SFLOAT` specifies a four-component, 256-bit signed floating-point format that has a 64-bit R component in bytes 0..7, a 64-bit G component in bytes 8..15, a 64-bit B component in bytes 16..23, and a 64-bit A component in bytes 24..31.

- `VK_FORMAT_B10G11R11_UFLOAT_PACK32` specifies a three-component, 32-bit packed unsigned floating-point format that has a 10-bit B component in bits 22..31, an 11-bit G component in bits 11..21, an 11-bit R component in bits 0..10. See Unsigned 10-Bit Floating-Point Numbers and Unsigned 11-Bit Floating-Point Numbers.

- `VK_FORMAT_E5B9G9R9_UFLOAT_PACK32` specifies a three-component, 32-bit packed unsigned floating-point format that has a 5-bit shared exponent in bits 27..31, a 9-bit B component mantissa in bits 18..26, a 9-bit G component mantissa in bits 9..17, and a 9-bit R component mantissa in bits 0..8.

- `VK_FORMAT_D16_UNORM` specifies a one-component, 16-bit unsigned normalized format that has a single 16-bit depth component.

- `VK_FORMAT_X8_D24_UNORM_PACK32` specifies a two-component, 32-bit format that has 24 unsigned normalized bits in the depth component and, optionally:, 8 bits that are unused.

- `VK_FORMAT_D32_SFLOAT` specifies a one-component, 32-bit signed floating-point format that has 32-bits in the depth component.

- `VK_FORMAT_S8_UINT` specifies a one-component, 8-bit unsigned integer format that has 8-bits in the stencil component.

- `VK_FORMAT_D16_UNORM_S8_UINT` specifies a two-component, 24-bit format that has 16 unsigned normalized bits in the depth component and 8 unsigned integer bits in the stencil component.

- `VK_FORMAT_D24_UNORM_S8_UINT` specifies a two-component, 32-bit packed format that has 8 unsigned integer bits in the stencil component, and 24 unsigned normalized bits in the depth component.

- `VK_FORMAT_D32_SFLOAT_S8_UINT` specifies a two-component format that has 32 signed float bits in the depth component and 8 unsigned integer bits in the stencil component. There are optionally: 24-bits that are unused.

- `VK_FORMAT_BC1_RGB_UNORM_BLOCK` specifies a three-component, block-compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGB texel data. This format has no alpha and is considered opaque.

- `VK_FORMAT_BC1_RGB_SRGB_BLOCK` specifies a three-component, block-compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGB texel data with sRGB nonlinear encoding. This format has no alpha and is considered opaque.

- `VK_FORMAT_BC1_RGBA_UNORM_BLOCK` specifies a four-component, block-compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGB texel data, and provides 1 bit of alpha.

- `VK_FORMAT_BC1_RGBA_SRGB_BLOCK` specifies a four-component, block-compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGB texel data with sRGB nonlinear encoding, and provides 1 bit of alpha.

- `VK_FORMAT_BC2_UNORM_BLOCK` specifies a four-component, block-compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data with the first 64 bits encoding alpha values followed by 64 bits encoding RGB values.

- `VK_FORMAT_BC2_SRGB_BLOCK` specifies a four-component, block-compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data with the first 64 bits encoding alpha values followed by 64 bits encoding RGB values with sRGB nonlinear encoding.

- `VK_FORMAT_BC3_UNORM_BLOCK` specifies a four-component, block-compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data with the first 64 bits encoding alpha values followed by 64 bits encoding RGB values.

- `VK_FORMAT_BC3_SRGB_BLOCK` specifies a four-component, block-compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data with the first 64 bits encoding alpha values followed by 64 bits encoding RGB values with sRGB nonlinear encoding.

- `VK_FORMAT_BC4_UNORM_BLOCK` specifies a one-component, block-compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized red texel data.

- `VK_FORMAT_BC4_SNORM_BLOCK` specifies a one-component, block-compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of signed normalized red texel data.

- `VK_FORMAT_BC5_UNORM_BLOCK` specifies a two-component, block-compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RG texel data with the first 64 bits encoding red values followed by 64 bits encoding green values.

- `VK_FORMAT_BC5_SNORM_BLOCK` specifies a two-component, block-compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of signed normalized RG texel data with the first 64 bits encoding red values followed by 64 bits encoding green values.

- `VK_FORMAT_BC6H_UFLOAT_BLOCK` specifies a three-component, block-compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned floating-point RGB texel data.

- `VK_FORMAT_BC6H_SFLOAT_BLOCK` specifies a three-component, block-compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of signed floating-point RGB texel data.

- `VK_FORMAT_BC7_UNORM_BLOCK` specifies a four-component, block-compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data.

- `VK_FORMAT_BC7_SRGB_BLOCK` specifies a four-component, block-compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components.

- `VK_FORMAT_ETC2_R8G8B8_UNORM_BLOCK` specifies a three-component, ETC2 compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGB texel data. This format has no alpha and is considered opaque.

- `VK_FORMAT_ETC2_R8G8B8_SRGB_BLOCK` specifies a three-component, ETC2 compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGB texel data with sRGB nonlinear encoding. This format has no alpha and is considered opaque.

- `VK_FORMAT_ETC2_R8G8B8A1_UNORM_BLOCK` specifies a four-component, ETC2 compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGB texel data, and provides 1 bit of alpha.

- `VK_FORMAT_ETC2_R8G8B8A1_SRGB_BLOCK` specifies a four-component, ETC2 compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGB texel data with sRGB nonlinear encoding, and provides 1 bit of alpha.

- `VK_FORMAT_ETC2_R8G8B8A8_UNORM_BLOCK` specifies a four-component, ETC2 compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data with the first 64 bits encoding alpha values followed by 64 bits encoding RGB values.

- `VK_FORMAT_ETC2_R8G8B8A8_SRGB_BLOCK` specifies a four-component, ETC2 compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data with the first 64 bits encoding alpha values followed by 64 bits encoding RGB values with sRGB nonlinear encoding applied.

- `VK_FORMAT_EAC_R11_UNORM_BLOCK` specifies a one-component, ETC2 compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized red texel data.

- `VK_FORMAT_EAC_R11_SNORM_BLOCK` specifies a one-component, ETC2 compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of signed normalized red texel data.

- `VK_FORMAT_EAC_R11G11_UNORM_BLOCK` specifies a two-component, ETC2 compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RG texel data with the first 64 bits encoding red values followed by 64 bits encoding green values.

- `VK_FORMAT_EAC_R11G11_SNORM_BLOCK` specifies a two-component, ETC2 compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of signed normalized RG texel data with the first 64 bits encoding red values followed by 64 bits encoding green values.

- `VK_FORMAT_ASTC_4x4_UNORM_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data.

- `VK_FORMAT_ASTC_4x4_SRGB_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components.

- `VK_FORMAT_ASTC_4x4_SFLOAT_BLOCK_EXT` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 4×4 rectangle of signed floating-point RGBA texel data.

- `VK_FORMAT_ASTC_5x4_UNORM_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 5×4 rectangle of unsigned normalized RGBA texel data.

- `VK_FORMAT_ASTC_5x4_SRGB_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 5×4 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components.

- `VK_FORMAT_ASTC_5x4_SFLOAT_BLOCK_EXT` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 5×4 rectangle of signed floating-point RGBA texel data.

- `VK_FORMAT_ASTC_5x5_UNORM_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 5×5 rectangle of unsigned normalized RGBA texel data.

- `VK_FORMAT_ASTC_5x5_SRGB_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 5×5 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components.

- `VK_FORMAT_ASTC_5x5_SFLOAT_BLOCK_EXT` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 5×5 rectangle of signed floating-point RGBA texel data.

- `VK_FORMAT_ASTC_6x5_UNORM_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 6×5 rectangle of unsigned normalized RGBA texel data.

- `VK_FORMAT_ASTC_6x5_SRGB_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 6×5 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components.

- `VK_FORMAT_ASTC_6x5_SFLOAT_BLOCK_EXT` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 6×5 rectangle of signed floating-point RGBA texel data.

- `VK_FORMAT_ASTC_6x6_UNORM_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 6×6 rectangle of unsigned normalized RGBA texel data.

- `VK_FORMAT_ASTC_6x6_SRGB_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 6×6 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components.

- `VK_FORMAT_ASTC_6x6_SFLOAT_BLOCK_EXT` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 6×6 rectangle of signed floating-point RGBA texel data.

- `VK_FORMAT_ASTC_8x5_UNORM_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes an 8×5 rectangle of unsigned normalized RGBA texel data.

- `VK_FORMAT_ASTC_8x5_SRGB_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes an 8×5 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components.

- `VK_FORMAT_ASTC_8x5_SFLOAT_BLOCK_EXT` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 8×5 rectangle of signed floating-point RGBA texel data.

- `VK_FORMAT_ASTC_8x6_UNORM_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes an 8×6 rectangle of unsigned normalized RGBA texel data.

- `VK_FORMAT_ASTC_8x6_SRGB_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes an 8×6 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components.

- `VK_FORMAT_ASTC_8x6_SFLOAT_BLOCK_EXT` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 8×6 rectangle of signed floating-point RGBA texel data.

- `VK_FORMAT_ASTC_8x8_UNORM_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes an 8×8 rectangle of unsigned normalized RGBA texel data.

- `VK_FORMAT_ASTC_8x8_SRGB_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes an 8×8 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components.

- `VK_FORMAT_ASTC_8x8_SFLOAT_BLOCK_EXT` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 8×8 rectangle of signed floating-point RGBA texel data.

- `VK_FORMAT_ASTC_10x5_UNORM_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 10×5 rectangle of unsigned normalized RGBA texel data.

- `VK_FORMAT_ASTC_10x5_SRGB_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 10×5 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components.

- `VK_FORMAT_ASTC_10x5_SFLOAT_BLOCK_EXT` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 10×5 rectangle of signed floating-point RGBA texel data.

- `VK_FORMAT_ASTC_10x6_UNORM_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 10×6 rectangle of unsigned normalized RGBA texel data.

- `VK_FORMAT_ASTC_10x6_SRGB_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 10×6 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components.

- `VK_FORMAT_ASTC_10x6_SFLOAT_BLOCK_EXT` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 10×6 rectangle of signed floating-point RGBA texel data.

- `VK_FORMAT_ASTC_10x8_UNORM_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 10×8 rectangle of unsigned normalized RGBA texel data.

- `VK_FORMAT_ASTC_10x8_SRGB_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 10×8 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components.

- `VK_FORMAT_ASTC_10x8_SFLOAT_BLOCK_EXT` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 10×8 rectangle of signed floating-point RGBA texel data.

- `VK_FORMAT_ASTC_10x10_UNORM_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 10×10 rectangle of unsigned normalized RGBA texel data.

- `VK_FORMAT_ASTC_10x10_SRGB_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 10×10 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components.

- `VK_FORMAT_ASTC_10x10_SFLOAT_BLOCK_EXT` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 10×10 rectangle of signed floating-point RGBA texel data.

- `VK_FORMAT_ASTC_12x10_UNORM_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 12×10 rectangle of unsigned normalized RGBA texel data.

- `VK_FORMAT_ASTC_12x10_SRGB_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 12×10 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components.

- `VK_FORMAT_ASTC_12x10_SFLOAT_BLOCK_EXT` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 12×10 rectangle of signed floating-point RGBA texel data.

- `VK_FORMAT_ASTC_12x12_UNORM_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 12×12 rectangle of unsigned normalized RGBA texel data.

- `VK_FORMAT_ASTC_12x12_SRGB_BLOCK` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 12×12 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components.

- `VK_FORMAT_ASTC_12x12_SFLOAT_BLOCK_EXT` specifies a four-component, ASTC compressed format where each 128-bit compressed texel block encodes a 12×12 rectangle of signed floating-point RGBA texel data.

- `VK_FORMAT_G8B8G8R8_422_UNORM` specifies a four-component, 32-bit format containing a pair of G components, an R component, and a B component, collectively encoding a 2×1 rectangle of unsigned normalized RGB texel data. One G value is present at each i coordinate, with the B and R values shared across both G values and thus recorded at half the horizontal resolution of the image. This format has an 8-bit G component for the even i coordinate in byte 0, an 8-bit B component in byte 1, an 8-bit G component for the odd i coordinate in byte 2, and an 8-bit R component in byte 3. Images in this format must be defined with a width that is a multiple of two. For the purposes of the constraints on copy extents, this format is treated as a compressed format with a 2×1 compressed texel block.

- `VK_FORMAT_B8G8R8G8_422_UNORM` specifies a four-component, 32-bit format containing a pair of G components, an R component, and a B component, collectively encoding a 2×1 rectangle of unsigned normalized RGB texel data. One G value is present at each i coordinate, with the B and R values shared across both G values and thus recorded at half the horizontal resolution of the image. This format has an 8-bit B component in byte 0, an 8-bit G component for the even i coordinate in byte 1, an 8-bit R component in byte 2, and an 8-bit G component for the odd i coordinate in byte 3. Images in this format must be defined with a width that is a multiple of two. For the purposes of the constraints on copy extents, this format is treated as a compressed format with a 2×1 compressed texel block.

- `VK_FORMAT_G8_B8_R8_3PLANE_420_UNORM` specifies an unsigned normalized multi-planar format that has an 8-bit G component in plane 0, an 8-bit B component in plane 1, and an 8-bit R component in plane 2. The horizontal and vertical dimensions of the R and B planes are halved relative to the image dimensions, and each R and B component is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\) and \(\lfloor j_G \times 0.5 \rfloor = j_B = j_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, using `VK_IMAGE_ASPECT_PLANE_0_BIT` for the G plane, `VK_IMAGE_ASPECT_PLANE_1_BIT` for the B plane, and `VK_IMAGE_ASPECT_PLANE_2_BIT` for the R plane. Images in this format must be defined with a width and height that is a multiple of two.

- `VK_FORMAT_G8_B8R8_2PLANE_420_UNORM` specifies an unsigned normalized multi-planar format that has an 8-bit G component in plane 0, and a two-component, 16-bit BR plane 1 consisting of an 8-bit B component in byte 0 and an 8-bit R component in byte 1. The horizontal and vertical dimensions of the BR plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\) and \(\lfloor j_G \times 0.5 \rfloor = j_B = j_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, using `VK_IMAGE_ASPECT_PLANE_0_BIT` for the G plane, and `VK_IMAGE_ASPECT_PLANE_1_BIT` for the BR plane. Images in this format must be defined with a width and height that is a multiple of two.

- `VK_FORMAT_G8_B8_R8_3PLANE_422_UNORM` specifies an unsigned normalized multi-planar format that has an 8-bit G component in plane 0, an 8-bit B component in plane 1, and an 8-bit R component in plane 2. The horizontal dimension of the R and B plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, using `VK_IMAGE_ASPECT_PLANE_0_BIT` for the G plane, `VK_IMAGE_ASPECT_PLANE_1_BIT` for the B plane, and `VK_IMAGE_ASPECT_PLANE_2_BIT` for the R plane. Images in this format must be defined with a width that is a multiple of two.

- `VK_FORMAT_G8_B8R8_2PLANE_422_UNORM` specifies an unsigned normalized multi-planar format that has an 8-bit G component in plane 0, and a two-component, 16-bit BR plane 1 consisting of an 8-bit B component in byte 0 and an 8-bit R component in byte 1. The horizontal dimensions of the BR plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, using `VK_IMAGE_ASPECT_PLANE_0_BIT` for the G plane, and `VK_IMAGE_ASPECT_PLANE_1_BIT` for the BR plane. Images in this format must be defined with a width that is a multiple of two.

- `VK_FORMAT_G8_B8_R8_3PLANE_444_UNORM` specifies an unsigned normalized multi-planar format that has an 8-bit G component in plane 0, an 8-bit B component in plane 1, and an 8-bit R component in plane 2. Each plane has the same dimensions and each R, G and B component contributes to a single texel. The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, using `VK_IMAGE_ASPECT_PLANE_0_BIT` for the G plane, `VK_IMAGE_ASPECT_PLANE_1_BIT` for the B plane, and `VK_IMAGE_ASPECT_PLANE_2_BIT` for the R plane.

- `VK_FORMAT_R10X6_UNORM_PACK16` specifies a one-component, 16-bit unsigned normalized format that has a single 10-bit R component in the top 10 bits of a 16-bit word, with the bottom 6 bits unused.

- `VK_FORMAT_R10X6G10X6_UNORM_2PACK16` specifies a two-component, 32-bit unsigned normalized format that has a 10-bit R component in the top 10 bits of the word in bytes 0..1, and a 10-bit G component in the top 10 bits of the word in bytes 2..3, with the bottom 6 bits of each word unused.

- `VK_FORMAT_R10X6G10X6B10X6A10X6_UNORM_4PACK16` specifies a four-component, 64-bit unsigned normalized format that has a 10-bit R component in the top 10 bits of the word in bytes 0..1, a 10-bit G component in the top 10 bits of the word in bytes 2..3, a 10-bit B component in the top 10 bits of the word in bytes 4..5, and a 10-bit A component in the top 10 bits of the word in bytes 6..7, with the bottom 6 bits of each word unused.

- `VK_FORMAT_G10X6B10X6G10X6R10X6_422_UNORM_4PACK16` specifies a four-component, 64-bit format containing a pair of G components, an R component, and a B component, collectively encoding a 2×1 rectangle of unsigned normalized RGB texel data. One G value is present at each i coordinate, with the B and R values shared across both G values and thus recorded at half the horizontal resolution of the image. This format has a 10-bit G component for the even i coordinate in the top 10 bits of the word in bytes 0..1, a 10-bit B component in the top 10 bits of the word in bytes 2..3, a 10-bit G component for the odd i coordinate in the top 10 bits of the word in bytes 4..5, and a 10-bit R component in the top 10 bits of the word in bytes 6..7, with the bottom 6 bits of each word unused. Images in this format must be defined with a width that is a multiple of two. For the purposes of the constraints on copy extents, this format is treated as a compressed format with a 2×1 compressed texel block.

- `VK_FORMAT_B10X6G10X6R10X6G10X6_422_UNORM_4PACK16` specifies a four-component, 64-bit format containing a pair of G components, an R component, and a B component, collectively encoding a 2×1 rectangle of unsigned normalized RGB texel data. One G value is present at each i coordinate, with the B and R values shared across both G values and thus recorded at half the horizontal resolution of the image. This format has a 10-bit B component in the top 10 bits of the word in bytes 0..1, a 10-bit G component for the even i coordinate in the top 10 bits of the word in bytes 2..3, a 10-bit R component in the top 10 bits of the word in bytes 4..5, and a 10-bit G component for the odd i coordinate in the top 10 bits of the word in bytes 6..7, with the bottom 6 bits of each word unused. Images in this format must be defined with a width that is a multiple of two. For the purposes of the constraints on copy extents, this format is treated as a compressed format with a 2×1 compressed texel block.

- `VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_420_UNORM_3PACK16` specifies an unsigned normalized multi-planar format that has a 10-bit G component in the top 10 bits of each 16-bit word of plane 0, a 10-bit B component in the top 10 bits of each 16-bit word of plane 1, and a 10-bit R component in the top 10 bits of each 16-bit word of plane 2, with the bottom 6 bits of each word unused. The horizontal and vertical dimensions of the R and B planes are halved relative to the image dimensions, and each R and B component is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\) and \(\lfloor j_G \times 0.5 \rfloor = j_B = j_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, using `VK_IMAGE_ASPECT_PLANE_0_BIT` for the G plane, `VK_IMAGE_ASPECT_PLANE_1_BIT` for the B plane, and `VK_IMAGE_ASPECT_PLANE_2_BIT` for the R plane. Images in this format must be defined with a width and height that is a multiple of two.

- `VK_FORMAT_G10X6_B10X6R10X6_2PLANE_420_UNORM_3PACK16` specifies an unsigned normalized multi-planar format that has a 10-bit G component in the top 10 bits of each 16-bit word of plane 0, and a two-component, 32-bit BR plane 1 consisting of a 10-bit B component in the top 10 bits of the word in bytes 0..1, and a 10-bit R component in the top 10 bits of the word in bytes 2..3, the bottom 6 bits of each word unused. The horizontal and vertical dimensions of the BR plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\) and \(\lfloor j_G \times 0.5 \rfloor = j_B = j_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, using `VK_IMAGE_ASPECT_PLANE_0_BIT` for the G plane, and `VK_IMAGE_ASPECT_PLANE_1_BIT` for the BR plane. Images in this format must be defined with a width and height that is a multiple of two.

- `VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_422_UNORM_3PACK16` specifies an unsigned normalized multi-planar format that has a 10-bit G component in the top 10 bits of each 16-bit word of plane 0, a 10-bit B component in the top 10 bits of each 16-bit word of plane 1, and a 10-bit R component in the top 10 bits of each 16-bit word of plane 2, with the bottom 6 bits of each word unused. The horizontal dimension of the R and B plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, using `VK_IMAGE_ASPECT_PLANE_0_BIT` for the G plane, `VK_IMAGE_ASPECT_PLANE_1_BIT` for the B plane, and `VK_IMAGE_ASPECT_PLANE_2_BIT` for the R plane. Images in this format must be defined with a width that is a multiple of two.

- `VK_FORMAT_G10X6_B10X6R10X6_2PLANE_422_UNORM_3PACK16` specifies an unsigned normalized multi-planar format that has a 10-bit G component in the top 10 bits of each 16-bit word of plane 0, and a two-component, 32-bit BR plane 1 consisting of a 10-bit B component in the top 10 bits of the word in bytes 0..1, and a 10-bit R component in the top 10 bits of the word in bytes 2..3, the bottom 6 bits of each word unused. The horizontal dimensions of the BR plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, using `VK_IMAGE_ASPECT_PLANE_0_BIT` for the G plane, and `VK_IMAGE_ASPECT_PLANE_1_BIT` for the BR plane. Images in this format must be defined with a width that is a multiple of two.

- `VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_444_UNORM_3PACK16` specifies an unsigned normalized multi-planar format that has a 10-bit G component in the top 10 bits of each 16-bit word of plane 0, a 10-bit B component in the top 10 bits of each 16-bit word of plane 1, and a 10-bit R component in the top 10 bits of each 16-bit word of plane 2, with the bottom 6 bits of each word unused. Each plane has the same dimensions and each R, G and B component contributes to a single texel. The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, using `VK_IMAGE_ASPECT_PLANE_0_BIT` for the G plane, `VK_IMAGE_ASPECT_PLANE_1_BIT` for the B plane, and `VK_IMAGE_ASPECT_PLANE_2_BIT` for the R plane.

- `VK_FORMAT_R12X4_UNORM_PACK16` specifies a one-component, 16-bit unsigned normalized format that has a single 12-bit R component in the top 12 bits of a 16-bit word, with the bottom 4 bits unused.

- `VK_FORMAT_R12X4G12X4_UNORM_2PACK16` specifies a two-component, 32-bit unsigned normalized format that has a 12-bit R component in the top 12 bits of the word in bytes 0..1, and a 12-bit G component in the top 12 bits of the word in bytes 2..3, with the bottom 4 bits of each word unused.

- `VK_FORMAT_R12X4G12X4B12X4A12X4_UNORM_4PACK16` specifies a four-component, 64-bit unsigned normalized format that has a 12-bit R component in the top 12 bits of the word in bytes 0..1, a 12-bit G component in the top 12 bits of the word in bytes 2..3, a 12-bit B component in the top 12 bits of the word in bytes 4..5, and a 12-bit A component in the top 12 bits of the word in bytes 6..7, with the bottom 4 bits of each word unused.

- `VK_FORMAT_G12X4B12X4G12X4R12X4_422_UNORM_4PACK16` specifies a four-component, 64-bit format containing a pair of G components, an R component, and a B component, collectively encoding a 2×1 rectangle of unsigned normalized RGB texel data. One G value is present at each i coordinate, with the B and R values shared across both G values and thus recorded at half the horizontal resolution of the image. This format has a 12-bit G component for the even i coordinate in the top 12 bits of the word in bytes 0..1, a 12-bit B component in the top 12 bits of the word in bytes 2..3, a 12-bit G component for the odd i coordinate in the top 12 bits of the word in bytes 4..5, and a 12-bit R component in the top 12 bits of the word in bytes 6..7, with the bottom 4 bits of each word unused. Images in this format must be defined with a width that is a multiple of two. For the purposes of the constraints on copy extents, this format is treated as a compressed format with a 2×1 compressed texel block.

- `VK_FORMAT_B12X4G12X4R12X4G12X4_422_UNORM_4PACK16` specifies a four-component, 64-bit format containing a pair of G components, an R component, and a B component, collectively encoding a 2×1 rectangle of unsigned normalized RGB texel data. One G value is present at each i coordinate, with the B and R values shared across both G values and thus recorded at half the horizontal resolution of the image. This format has a 12-bit B component in the top 12 bits of the word in bytes 0..1, a 12-bit G component for the even i coordinate in the top 12 bits of the word in bytes 2..3, a 12-bit R component in the top 12 bits of the word in bytes 4..5, and a 12-bit G component for the odd i coordinate in the top 12 bits of the word in bytes 6..7, with the bottom 4 bits of each word unused. Images in this format must be defined with a width that is a multiple of two. For the purposes of the constraints on copy extents, this format is treated as a compressed format with a 2×1 compressed texel block.

- `VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_420_UNORM_3PACK16` specifies an unsigned normalized multi-planar format that has a 12-bit G component in the top 12 bits of each 16-bit word of plane 0, a 12-bit B component in the top 12 bits of each 16-bit word of plane 1, and a 12-bit R component in the top 12 bits of each 16-bit word of plane 2, with the bottom 4 bits of each word unused. The horizontal and vertical dimensions of the R and B planes are halved relative to the image dimensions, and each R and B component is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\) and \(\lfloor j_G \times 0.5 \rfloor = j_B = j_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, using `VK_IMAGE_ASPECT_PLANE_0_BIT` for the G plane, `VK_IMAGE_ASPECT_PLANE_1_BIT` for the B plane, and `VK_IMAGE_ASPECT_PLANE_2_BIT` for the R plane. Images in this format must be defined with a width and height that is a multiple of two.

- `VK_FORMAT_G12X4_B12X4R12X4_2PLANE_420_UNORM_3PACK16` specifies an unsigned normalized multi-planar format that has a 12-bit G component in the top 12 bits of each 16-bit word of plane 0, and a two-component, 32-bit BR plane 1 consisting of a 12-bit B component in the top 12 bits of the word in bytes 0..1, and a 12-bit R component in the top 12 bits of the word in bytes 2..3, the bottom 4 bits of each word unused. The horizontal and vertical dimensions of the BR plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\) and \(\lfloor j_G \times 0.5 \rfloor = j_B = j_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, using `VK_IMAGE_ASPECT_PLANE_0_BIT` for the G plane, and `VK_IMAGE_ASPECT_PLANE_1_BIT` for the BR plane. Images in this format must be defined with a width and height that is a multiple of two.

- `VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_422_UNORM_3PACK16` specifies an unsigned normalized multi-planar format that has a 12-bit G component in the top 12 bits of each 16-bit word of plane 0, a 12-bit B component in the top 12 bits of each 16-bit word of plane 1, and a 12-bit R component in the top 12 bits of each 16-bit word of plane 2, with the bottom 4 bits of each word unused. The horizontal dimension of the R and B plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, using `VK_IMAGE_ASPECT_PLANE_0_BIT` for the G plane, `VK_IMAGE_ASPECT_PLANE_1_BIT` for the B plane, and `VK_IMAGE_ASPECT_PLANE_2_BIT` for the R plane. Images in this format must be defined with a width that is a multiple of two.

- `VK_FORMAT_G12X4_B12X4R12X4_2PLANE_422_UNORM_3PACK16` specifies an unsigned normalized multi-planar format that has a 12-bit G component in the top 12 bits of each 16-bit word of plane 0, and a two-component, 32-bit BR plane 1 consisting of a 12-bit B component in the top 12 bits of the word in bytes 0..1, and a 12-bit R component in the top 12 bits of the word in bytes 2..3, the bottom 4 bits of each word unused. The horizontal dimensions of the BR plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, using `VK_IMAGE_ASPECT_PLANE_0_BIT` for the G plane, and `VK_IMAGE_ASPECT_PLANE_1_BIT` for the BR plane. Images in this format must be defined with a width that is a multiple of two.

- `VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_444_UNORM_3PACK16` specifies an unsigned normalized multi-planar format that has a 12-bit G component in the top 12 bits of each 16-bit word of plane 0, a 12-bit B component in the top 12 bits of each 16-bit word of plane 1, and a 12-bit R component in the top 12 bits of each 16-bit word of plane 2, with the bottom 4 bits of each word unused. Each plane has the same dimensions and each R, G and B component contributes to a single texel. The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, using `VK_IMAGE_ASPECT_PLANE_0_BIT` for the G plane, `VK_IMAGE_ASPECT_PLANE_1_BIT` for the B plane, and `VK_IMAGE_ASPECT_PLANE_2_BIT` for the R plane.

- `VK_FORMAT_G16B16G16R16_422_UNORM` specifies a four-component, 64-bit format containing a pair of G components, an R component, and a B component, collectively encoding a 2×1 rectangle of unsigned normalized RGB texel data. One G value is present at each i coordinate, with the B and R values shared across both G values and thus recorded at half the horizontal resolution of the image. This format has a 16-bit G component for the even i coordinate in the word in bytes 0..1, a 16-bit B component in the word in bytes 2..3, a 16-bit G component for the odd i coordinate in the word in bytes 4..5, and a 16-bit R component in the word in bytes 6..7. Images in this format must be defined with a width that is a multiple of two. For the purposes of the constraints on copy extents, this format is treated as a compressed format with a 2×1 compressed texel block.

- `VK_FORMAT_B16G16R16G16_422_UNORM` specifies a four-component, 64-bit format containing a pair of G components, an R component, and a B component, collectively encoding a 2×1 rectangle of unsigned normalized RGB texel data. One G value is present at each i coordinate, with the B and R values shared across both G values and thus recorded at half the horizontal resolution of the image. This format has a 16-bit B component in the word in bytes 0..1, a 16-bit G component for the even i coordinate in the word in bytes 2..3, a 16-bit R component in the word in bytes 4..5, and a 16-bit G component for the odd i coordinate in the word in bytes 6..7. Images in this format must be defined with a width that is a multiple of two. For the purposes of the constraints on copy extents, this format is treated as a compressed format with a 2×1 compressed texel block.

- `VK_FORMAT_G16_B16_R16_3PLANE_420_UNORM` specifies an unsigned normalized multi-planar format that has a 16-bit G component in each 16-bit word of plane 0, a 16-bit B component in each 16-bit word of plane 1, and a 16-bit R component in each 16-bit word of plane 2. The horizontal and vertical dimensions of the R and B planes are halved relative to the image dimensions, and each R and B component is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\) and \(\lfloor j_G \times 0.5 \rfloor = j_B = j_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, using `VK_IMAGE_ASPECT_PLANE_0_BIT` for the G plane, `VK_IMAGE_ASPECT_PLANE_1_BIT` for the B plane, and `VK_IMAGE_ASPECT_PLANE_2_BIT` for the R plane. Images in this format must be defined with a width and height that is a multiple of two.

- `VK_FORMAT_G16_B16R16_2PLANE_420_UNORM` specifies an unsigned normalized multi-planar format that has a 16-bit G component in each 16-bit word of plane 0, and a two-component, 32-bit BR plane 1 consisting of a 16-bit B component in the word in bytes 0..1, and a 16-bit R component in the word in bytes 2..3. The horizontal and vertical dimensions of the BR plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\) and \(\lfloor j_G \times 0.5 \rfloor = j_B = j_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, using `VK_IMAGE_ASPECT_PLANE_0_BIT` for the G plane, and `VK_IMAGE_ASPECT_PLANE_1_BIT` for the BR plane. Images in this format must be defined with a width and height that is a multiple of two.

- `VK_FORMAT_G16_B16_R16_3PLANE_422_UNORM` specifies an unsigned normalized multi-planar format that has a 16-bit G component in each 16-bit word of plane 0, a 16-bit B component in each 16-bit word of plane 1, and a 16-bit R component in each 16-bit word of plane 2. The horizontal dimension of the R and B plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, using `VK_IMAGE_ASPECT_PLANE_0_BIT` for the G plane, `VK_IMAGE_ASPECT_PLANE_1_BIT` for the B plane, and `VK_IMAGE_ASPECT_PLANE_2_BIT` for the R plane. Images in this format must be defined with a width that is a multiple of two.

- `VK_FORMAT_G16_B16R16_2PLANE_422_UNORM` specifies an unsigned normalized multi-planar format that has a 16-bit G component in each 16-bit word of plane 0, and a two-component, 32-bit BR plane 1 consisting of a 16-bit B component in the word in bytes 0..1, and a 16-bit R component in the word in bytes 2..3. The horizontal dimensions of the BR plane is halved relative to the image dimensions, and each R and B value is shared with the G components for which \(\lfloor i_G \times 0.5 \rfloor = i_B = i_R\). The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, using `VK_IMAGE_ASPECT_PLANE_0_BIT` for the G plane, and `VK_IMAGE_ASPECT_PLANE_1_BIT` for the BR plane. Images in this format must be defined with a width that is a multiple of two.

- `VK_FORMAT_G16_B16_R16_3PLANE_444_UNORM` specifies an unsigned normalized multi-planar format that has a 16-bit G component in each 16-bit word of plane 0, a 16-bit B component in each 16-bit word of plane 1, and a 16-bit R component in each 16-bit word of plane 2. Each plane has the same dimensions and each R, G and B component contributes to a single texel. The location of each plane when this image is in linear layout can be determined via vkGetImageSubresourceLayout, using `VK_IMAGE_ASPECT_PLANE_0_BIT` for the G plane, `VK_IMAGE_ASPECT_PLANE_1_BIT` for the B plane, and `VK_IMAGE_ASPECT_PLANE_2_BIT` for the R plane.

- `VK_FORMAT_PVRTC1_2BPP_UNORM_BLOCK_IMG` specifies a four-component, PVRTC compressed format where each 64-bit compressed texel block encodes an 8×4 rectangle of unsigned normalized RGBA texel data.

- `VK_FORMAT_PVRTC1_4BPP_UNORM_BLOCK_IMG` specifies a four-component, PVRTC compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data.

- `VK_FORMAT_PVRTC2_2BPP_UNORM_BLOCK_IMG` specifies a four-component, PVRTC compressed format where each 64-bit compressed texel block encodes an 8×4 rectangle of unsigned normalized RGBA texel data.

- `VK_FORMAT_PVRTC2_4BPP_UNORM_BLOCK_IMG` specifies a four-component, PVRTC compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data.

- `VK_FORMAT_PVRTC1_2BPP_SRGB_BLOCK_IMG` specifies a four-component, PVRTC compressed format where each 64-bit compressed texel block encodes an 8×4 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components.

- `VK_FORMAT_PVRTC1_4BPP_SRGB_BLOCK_IMG` specifies a four-component, PVRTC compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components.

- `VK_FORMAT_PVRTC2_2BPP_SRGB_BLOCK_IMG` specifies a four-component, PVRTC compressed format where each 64-bit compressed texel block encodes an 8×4 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components.

- `VK_FORMAT_PVRTC2_4BPP_SRGB_BLOCK_IMG` specifies a four-component, PVRTC compressed format where each 64-bit compressed texel block encodes a 4×4 rectangle of unsigned normalized RGBA texel data with sRGB nonlinear encoding applied to the RGB components.

#### 39.1.1. Compatible formats of planes of multi-planar formats

Individual planes of multi-planar formats are compatible with single-plane formats if they occupy the same number of bits per texel block. In the following table, individual planes of a multi-planar format are compatible with the format listed against the relevant plane index for that multi-planar format.

Table 47. Plane Format Compatibility Table
Plane | Compatible format for plane | Width relative to the width w of the plane with the largest dimensions | Height relative to the height h of the plane with the largest dimensions
--- | --- | --- | ---
`VK_FORMAT_G8_B8_R8_3PLANE_420_UNORM`
0 | `VK_FORMAT_R8_UNORM` | w | h
1 | `VK_FORMAT_R8_UNORM` | w/2 | h/2
2 | `VK_FORMAT_R8_UNORM` | w/2 | h/2
`VK_FORMAT_G8_B8R8_2PLANE_420_UNORM`
0 | `VK_FORMAT_R8_UNORM` | w | h
1 | `VK_FORMAT_R8G8_UNORM` | w/2 | h/2
`VK_FORMAT_G8_B8_R8_3PLANE_422_UNORM`
0 | `VK_FORMAT_R8_UNORM` | w | h
1 | `VK_FORMAT_R8_UNORM` | w/2 | h
2 | `VK_FORMAT_R8_UNORM` | w/2 | h
`VK_FORMAT_G8_B8R8_2PLANE_422_UNORM`
0 | `VK_FORMAT_R8_UNORM` | w | h
1 | `VK_FORMAT_R8G8_UNORM` | w/2 | h
`VK_FORMAT_G8_B8_R8_3PLANE_444_UNORM`
0 | `VK_FORMAT_R8_UNORM` | w | h
1 | `VK_FORMAT_R8_UNORM` | w | h
2 | `VK_FORMAT_R8_UNORM` | w | h
`VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_420_UNORM_3PACK16`
0 | `VK_FORMAT_R10X6_UNORM_PACK16` | w | h
1 | `VK_FORMAT_R10X6_UNORM_PACK16` | w/2 | h/2
2 | `VK_FORMAT_R10X6_UNORM_PACK16` | w/2 | h/2
`VK_FORMAT_G10X6_B10X6R10X6_2PLANE_420_UNORM_3PACK16`
0 | `VK_FORMAT_R10X6_UNORM_PACK16` | w | h
1 | `VK_FORMAT_R10X6G10X6_UNORM_2PACK16` | w/2 | h/2
`VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_422_UNORM_3PACK16`
0 | `VK_FORMAT_R10X6_UNORM_PACK16` | w | h
1 | `VK_FORMAT_R10X6_UNORM_PACK16` | w/2 | h
2 | `VK_FORMAT_R10X6_UNORM_PACK16` | w/2 | h
`VK_FORMAT_G10X6_B10X6R10X6_2PLANE_422_UNORM_3PACK16`
0 | `VK_FORMAT_R10X6_UNORM_PACK16` | w | h
1 | `VK_FORMAT_R10X6G10X6_UNORM_2PACK16` | w/2 | h
`VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_444_UNORM_3PACK16`
0 | `VK_FORMAT_R10X6_UNORM_PACK16` | w | h
1 | `VK_FORMAT_R10X6_UNORM_PACK16` | w | h
2 | `VK_FORMAT_R10X6_UNORM_PACK16` | w | h
`VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_420_UNORM_3PACK16`
0 | `VK_FORMAT_R12X4_UNORM_PACK16` | w | h
1 | `VK_FORMAT_R12X4_UNORM_PACK16` | w/2 | h/2
2 | `VK_FORMAT_R12X4_UNORM_PACK16` | w/2 | h/2
`VK_FORMAT_G12X4_B12X4R12X4_2PLANE_420_UNORM_3PACK16`
0 | `VK_FORMAT_R12X4_UNORM_PACK16` | w | h
1 | `VK_FORMAT_R12X4G12X4_UNORM_2PACK16` | w/2 | h/2
`VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_422_UNORM_3PACK16`
0 | `VK_FORMAT_R12X4_UNORM_PACK16` | w | h
1 | `VK_FORMAT_R12X4_UNORM_PACK16` | w/2 | h
2 | `VK_FORMAT_R12X4_UNORM_PACK16` | w/2 | h
`VK_FORMAT_G12X4_B12X4R12X4_2PLANE_422_UNORM_3PACK16`
0 | `VK_FORMAT_R12X4_UNORM_PACK16` | w | h
1 | `VK_FORMAT_R12X4G12X4_UNORM_2PACK16` | w/2 | h
`VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_444_UNORM_3PACK16`
0 | `VK_FORMAT_R12X4_UNORM_PACK16` | w | h
1 | `VK_FORMAT_R12X4_UNORM_PACK16` | w | h
2 | `VK_FORMAT_R12X4_UNORM_PACK16` | w | h
`VK_FORMAT_G16_B16_R16_3PLANE_420_UNORM`
0 | `VK_FORMAT_R16_UNORM` | w | h
1 | `VK_FORMAT_R16_UNORM` | w/2 | h/2
2 | `VK_FORMAT_R16_UNORM` | w/2 | h/2
`VK_FORMAT_G16_B16R16_2PLANE_420_UNORM`
0 | `VK_FORMAT_R16_UNORM` | w | h
1 | `VK_FORMAT_R16G16_UNORM` | w/2 | h/2
`VK_FORMAT_G16_B16_R16_3PLANE_422_UNORM`
0 | `VK_FORMAT_R16_UNORM` | w | h
1 | `VK_FORMAT_R16_UNORM` | w/2 | h
2 | `VK_FORMAT_R16_UNORM` | w/2 | h
`VK_FORMAT_G16_B16R16_2PLANE_422_UNORM`
0 | `VK_FORMAT_R16_UNORM` | w | h
1 | `VK_FORMAT_R16G16_UNORM` | w/2 | h
`VK_FORMAT_G16_B16_R16_3PLANE_444_UNORM`
0 | `VK_FORMAT_R16_UNORM` | w | h
1 | `VK_FORMAT_R16_UNORM` | w | h
2 | `VK_FORMAT_R16_UNORM` | w | h

#### 39.1.2. Packed Formats

For the purposes of address alignment when accessing buffer memory containing vertex attribute or texel data, the following formats are considered packed - whole texels or attributes are stored in bitfields of a single 8-, 16-, or 32-bit fundamental data type.

- Packed into 8-bit data types:

  - `VK_FORMAT_R4G4_UNORM_PACK8`

- Packed into 16-bit data types:

  - `VK_FORMAT_R4G4B4A4_UNORM_PACK16`

  - `VK_FORMAT_B4G4R4A4_UNORM_PACK16`

  - `VK_FORMAT_R5G6B5_UNORM_PACK16`

  - `VK_FORMAT_B5G6R5_UNORM_PACK16`

  - `VK_FORMAT_R5G5B5A1_UNORM_PACK16`

  - `VK_FORMAT_B5G5R5A1_UNORM_PACK16`

  - `VK_FORMAT_A1R5G5B5_UNORM_PACK16`

- Packed into 32-bit data types:

  - `VK_FORMAT_A8B8G8R8_UNORM_PACK32`

  - `VK_FORMAT_A8B8G8R8_SNORM_PACK32`

  - `VK_FORMAT_A8B8G8R8_USCALED_PACK32`

  - `VK_FORMAT_A8B8G8R8_SSCALED_PACK32`

  - `VK_FORMAT_A8B8G8R8_UINT_PACK32`

  - `VK_FORMAT_A8B8G8R8_SINT_PACK32`

  - `VK_FORMAT_A8B8G8R8_SRGB_PACK32`

  - `VK_FORMAT_A2R10G10B10_UNORM_PACK32`

  - `VK_FORMAT_A2R10G10B10_SNORM_PACK32`

  - `VK_FORMAT_A2R10G10B10_USCALED_PACK32`

  - `VK_FORMAT_A2R10G10B10_SSCALED_PACK32`

  - `VK_FORMAT_A2R10G10B10_UINT_PACK32`

  - `VK_FORMAT_A2R10G10B10_SINT_PACK32`

  - `VK_FORMAT_A2B10G10R10_UNORM_PACK32`

  - `VK_FORMAT_A2B10G10R10_SNORM_PACK32`

  - `VK_FORMAT_A2B10G10R10_USCALED_PACK32`

  - `VK_FORMAT_A2B10G10R10_SSCALED_PACK32`

  - `VK_FORMAT_A2B10G10R10_UINT_PACK32`

  - `VK_FORMAT_A2B10G10R10_SINT_PACK32`

  - `VK_FORMAT_B10G11R11_UFLOAT_PACK32`

  - `VK_FORMAT_E5B9G9R9_UFLOAT_PACK32`

  - `VK_FORMAT_X8_D24_UNORM_PACK32`

#### 39.1.3. Identification of Formats

A “format” is represented by a single enum value. The name of a format is usually built up by using the following pattern:

        VK_FORMAT_{component-format|compression-scheme}_{numeric-format}

The component-format indicates either the size of the R, G, B, and A components (if they are present) in the case of a color format, or the size of the depth (D) and stencil (S) components (if they are present) in the case of a depth/stencil format (see below). An X indicates a component that is unused, but may be present for padding.

Table 48. Interpretation of Numeric Format
Numeric format | SPIR-V Sampled Type | Description
--- | --- | ---
`UNORM` | OpTypeFloat | The components are unsigned normalized values in the range [0,1]
`SNORM` | OpTypeFloat | The components are signed normalized values in the range [-1,1]
`USCALED` | OpTypeFloat | The components are unsigned integer values that get converted to floating-point in the range [0,2n-1]
`SSCALED` | OpTypeFloat | The components are signed integer values that get converted to floating-point in the range [-2n-1,2n-1-1]
`UINT` | OpTypeInt | The components are unsigned integer values in the range [0,2n-1]
`SINT` | OpTypeInt | The components are signed integer values in the range [-2n-1,2n-1-1]
`UFLOAT` | OpTypeFloat | The components are unsigned floating-point numbers (used by packed, shared exponent, and some compressed formats)
`SFLOAT` | OpTypeFloat | The components are signed floating-point numbers
`SRGB` | OpTypeFloat | The R, G, and B components are unsigned normalized values that represent values using sRGB nonlinear encoding, while the A component (if one exists) is a regular unsigned normalized value

The suffix `_PACKnn` indicates that the format is packed into an underlying type with nn bits. The suffix `_mPACKnn` is a short-hand that indicates that the format has several components (which may or may not be stored in separate planes) that are each packed into an underlying type with nn bits.

The suffix `_BLOCK` indicates that the format is a block-compressed format, with the representation of multiple pixels encoded interdependently within a region.

Table 49. Interpretation of Compression Scheme
Compression scheme | Description
--- | ---
`BC` | Block Compression. See Block-Compressed Image Formats.
`ETC2` | Ericsson Texture Compression. See ETC Compressed Image Formats.
`EAC` | ETC2 Alpha Compression. See ETC Compressed Image Formats.
`ASTC` | Adaptive Scalable Texture Compression (LDR Profile). See ASTC Compressed Image Formats.

For multi-planar images, the components in separate planes are separated by underscores, and the number of planes is indicated by the addition of a `_2PLANE` or `_3PLANE` suffix. Similarly, the separate aspects of depth-stencil formats are separated by underscores, although these are not considered separate planes. Formats are suffixed by `_422` to indicate that planes other than the first are reduced in size by a factor of two horizontally or that the R and B values appear at half the horizontal frequency of the G values, `_420` to indicate that planes other than the first are reduced in size by a factor of two both horizontally and vertically, and `_444` for consistency to indicate that all three planes of a three-planar image are the same size.

| Note No common format has a single plane containing both R and B channels but does not store these channels at reduced horizontal resolution.

#### 39.1.4. Representation and Texel Block Size

Color formats must be represented in memory in exactly the form indicated by the format’s name. This means that promoting one format to another with more bits per component and/or additional components must not occur for color formats. Depth/stencil formats have more relaxed requirements as discussed below.

Each format has a texel block size, the number of bytes used to store one texel block (a single addressable element of an uncompressed image, or a single compressed block of a compressed image). The texel block size for each format is shown in the Compatible formats table.

The representation of non-packed formats is that the first component specified in the name of the format is in the lowest memory addresses and the last component specified is in the highest memory addresses. See Byte mappings for non-packed/compressed color formats. The in-memory ordering of bytes within a component is determined by the host endianness.

Table 50. Byte mappings for non-packed/compressed color formats
0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | ← Byte
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
R | `VK_FORMAT_R8_*`
R | G | `VK_FORMAT_R8G8_*`
R | G | B | `VK_FORMAT_R8G8B8_*`
B | G | R | `VK_FORMAT_B8G8R8_*`
R | G | B | A | `VK_FORMAT_R8G8B8A8_*`
B | G | R | A | `VK_FORMAT_B8G8R8A8_*`
G0 | B | G1 | R | `VK_FORMAT_G8B8G8R8_422_UNORM`
B | G0 | R | G1 | `VK_FORMAT_B8G8R8G8_422_UNORM`
R | `VK_FORMAT_R16_*`
R | G | `VK_FORMAT_R16G16_*`
R | G | B | `VK_FORMAT_R16G16B16_*`
R | G | B | A | `VK_FORMAT_R16G16B16A16_*`
G0 | B | G1 | R | `VK_FORMAT_G10X6B10X6G10X6R10X6_4PACK16_422_UNORM` `VK_FORMAT_G12X4B12X4G12X4R12X4_4PACK16_422_UNORM` `VK_FORMAT_G16B16G16R16_UNORM`
B | G0 | R | G1 | `VK_FORMAT_B10X6G10X6R10X6G10X6_4PACK16_422_UNORM` `VK_FORMAT_B12X4G12X4R12X4G12X4_4PACK16_422_UNORM` `VK_FORMAT_B16G16R16G16_422_UNORM`
R | `VK_FORMAT_R32_*`
R | G | `VK_FORMAT_R32G32_*`
R | G | B | `VK_FORMAT_R32G32B32_*`
R | G | B | A | `VK_FORMAT_R32G32B32A32_*`
R | `VK_FORMAT_R64_*`
R | G | `VK_FORMAT_R64G64_*`
`VK_FORMAT_R64G64B64_*` as `VK_FORMAT_R64G64_*` but with B in bytes 16-23
`VK_FORMAT_R64G64B64A64_*` as `VK_FORMAT_R64G64B64_*` but with A in bytes 24-31

Packed formats store multiple components within one underlying type. The bit representation is that the first component specified in the name of the format is in the most-significant bits and the last component specified is in the least-significant bits of the underlying type. The in-memory ordering of bytes comprising the underlying type is determined by the host endianness.

Table 51. Bit mappings for packed 8-bit formats
Bit
7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
`VK_FORMAT_R4G4_UNORM_PACK8`
R | G
3 | 2 | 1 | 0 | 3 | 2 | 1 | 0

Table 52. Bit mappings for packed 16-bit formats
Bit
15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
`VK_FORMAT_R4G4B4A4_UNORM_PACK16`
R | G | B | A
3 | 2 | 1 | 0 | 3 | 2 | 1 | 0 | 3 | 2 | 1 | 0 | 3 | 2 | 1 | 0
`VK_FORMAT_B4G4R4A4_UNORM_PACK16`
B | G | R | A
3 | 2 | 1 | 0 | 3 | 2 | 1 | 0 | 3 | 2 | 1 | 0 | 3 | 2 | 1 | 0
`VK_FORMAT_R5G6B5_UNORM_PACK16`
R | G | B
4 | 3 | 2 | 1 | 0 | 5 | 4 | 3 | 2 | 1 | 0 | 4 | 3 | 2 | 1 | 0
`VK_FORMAT_B5G6R5_UNORM_PACK16`
B | G | R
4 | 3 | 2 | 1 | 0 | 5 | 4 | 3 | 2 | 1 | 0 | 4 | 3 | 2 | 1 | 0
`VK_FORMAT_R5G5B5A1_UNORM_PACK16`
R | G | B | A
4 | 3 | 2 | 1 | 0 | 4 | 3 | 2 | 1 | 0 | 4 | 3 | 2 | 1 | 0 | 0
`VK_FORMAT_B5G5R5A1_UNORM_PACK16`
B | G | R | A
4 | 3 | 2 | 1 | 0 | 4 | 3 | 2 | 1 | 0 | 4 | 3 | 2 | 1 | 0 | 0
`VK_FORMAT_A1R5G5B5_UNORM_PACK16`
A | R | G | B
0 | 4 | 3 | 2 | 1 | 0 | 4 | 3 | 2 | 1 | 0 | 4 | 3 | 2 | 1 | 0
`VK_FORMAT_R10X6_UNORM_PACK16`
R | X
9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | 5 | 4 | 3 | 2 | 1 | 0
`VK_FORMAT_R12X4_UNORM_PACK16`
R | X
11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | 3 | 2 | 1 | 0

Table 53. Bit mappings for packed 32-bit formats
Bit
31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
`VK_FORMAT_A8B8G8R8_*_PACK32`
A | B | G | R
7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
`VK_FORMAT_A2R10G10B10_*_PACK32`
A | R | G | B
1 | 0 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
`VK_FORMAT_A2B10G10R10_*_PACK32`
A | B | G | R
1 | 0 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
`VK_FORMAT_B10G11R11_UFLOAT_PACK32`
B | G | R
9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
`VK_FORMAT_E5B9G9R9_UFLOAT_PACK32`
E | B | G | R
4 | 3 | 2 | 1 | 0 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
`VK_FORMAT_X8_D24_UNORM_PACK32`
X | D
7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0

#### 39.1.5. Depth/Stencil Formats

Depth/stencil formats are considered opaque and need not be stored in the exact number of bits per texel or component ordering indicated by the format enum. However, implementations must not substitute a different depth or stencil precision than that described in the format (e.g. D16 must not be implemented as D24 or D32).

#### 39.1.6. Format Compatibility Classes

Uncompressed color formats are compatible with each other if they occupy the same number of bits per texel block. Compressed color formats are compatible with each other if the only difference between them is the numerical type of the uncompressed pixels (e.g. signed vs. unsigned, or SRGB vs. UNORM encoding). Each depth/stencil format is only compatible with itself. In the following table, all the formats in the same row are compatible.

Table 54. Compatible Formats
Class, Texel Block Size, # Texels/Block | Formats
--- | ---
8-bit Block size 1 byte 1 texel/block | `VK_FORMAT_R4G4_UNORM_PACK8`, `VK_FORMAT_R8_UNORM`, `VK_FORMAT_R8_SNORM`, `VK_FORMAT_R8_USCALED`, `VK_FORMAT_R8_SSCALED`, `VK_FORMAT_R8_UINT`, `VK_FORMAT_R8_SINT`, `VK_FORMAT_R8_SRGB`
16-bit Block size 2 bytes 1 texel/block | `VK_FORMAT_R4G4B4A4_UNORM_PACK16`, `VK_FORMAT_B4G4R4A4_UNORM_PACK16`, `VK_FORMAT_R5G6B5_UNORM_PACK16`, `VK_FORMAT_B5G6R5_UNORM_PACK16`, `VK_FORMAT_R5G5B5A1_UNORM_PACK16`, `VK_FORMAT_B5G5R5A1_UNORM_PACK16`, `VK_FORMAT_A1R5G5B5_UNORM_PACK16`, `VK_FORMAT_R8G8_UNORM`, `VK_FORMAT_R8G8_SNORM`, `VK_FORMAT_R8G8_USCALED`, `VK_FORMAT_R8G8_SSCALED`, `VK_FORMAT_R8G8_UINT`, `VK_FORMAT_R8G8_SINT`, `VK_FORMAT_R8G8_SRGB`, `VK_FORMAT_R16_UNORM`, `VK_FORMAT_R16_SNORM`, `VK_FORMAT_R16_USCALED`, `VK_FORMAT_R16_SSCALED`, `VK_FORMAT_R16_UINT`, `VK_FORMAT_R16_SINT`, `VK_FORMAT_R16_SFLOAT`, `VK_FORMAT_R10X6_UNORM_PACK16`, `VK_FORMAT_R12X4_UNORM_PACK16`
24-bit Block size 3 bytes 1 texel/block | `VK_FORMAT_R8G8B8_UNORM`, `VK_FORMAT_R8G8B8_SNORM`, `VK_FORMAT_R8G8B8_USCALED`, `VK_FORMAT_R8G8B8_SSCALED`, `VK_FORMAT_R8G8B8_UINT`, `VK_FORMAT_R8G8B8_SINT`, `VK_FORMAT_R8G8B8_SRGB`, `VK_FORMAT_B8G8R8_UNORM`, `VK_FORMAT_B8G8R8_SNORM`, `VK_FORMAT_B8G8R8_USCALED`, `VK_FORMAT_B8G8R8_SSCALED`, `VK_FORMAT_B8G8R8_UINT`, `VK_FORMAT_B8G8R8_SINT`, `VK_FORMAT_B8G8R8_SRGB`
32-bit Block size 4 bytes 1 texel/block | `VK_FORMAT_R8G8B8A8_UNORM`, `VK_FORMAT_R8G8B8A8_SNORM`, `VK_FORMAT_R8G8B8A8_USCALED`, `VK_FORMAT_R8G8B8A8_SSCALED`, `VK_FORMAT_R8G8B8A8_UINT`, `VK_FORMAT_R8G8B8A8_SINT`, `VK_FORMAT_R8G8B8A8_SRGB`, `VK_FORMAT_B8G8R8A8_UNORM`, `VK_FORMAT_B8G8R8A8_SNORM`, `VK_FORMAT_B8G8R8A8_USCALED`, `VK_FORMAT_B8G8R8A8_SSCALED`, `VK_FORMAT_B8G8R8A8_UINT`, `VK_FORMAT_B8G8R8A8_SINT`, `VK_FORMAT_B8G8R8A8_SRGB`, `VK_FORMAT_A8B8G8R8_UNORM_PACK32`, `VK_FORMAT_A8B8G8R8_SNORM_PACK32`, `VK_FORMAT_A8B8G8R8_USCALED_PACK32`, `VK_FORMAT_A8B8G8R8_SSCALED_PACK32`, `VK_FORMAT_A8B8G8R8_UINT_PACK32`, `VK_FORMAT_A8B8G8R8_SINT_PACK32`, `VK_FORMAT_A8B8G8R8_SRGB_PACK32`, `VK_FORMAT_A2R10G10B10_UNORM_PACK32`, `VK_FORMAT_A2R10G10B10_SNORM_PACK32`, `VK_FORMAT_A2R10G10B10_USCALED_PACK32`, `VK_FORMAT_A2R10G10B10_SSCALED_PACK32`, `VK_FORMAT_A2R10G10B10_UINT_PACK32`, `VK_FORMAT_A2R10G10B10_SINT_PACK32`, `VK_FORMAT_A2B10G10R10_UNORM_PACK32`, `VK_FORMAT_A2B10G10R10_SNORM_PACK32`, `VK_FORMAT_A2B10G10R10_USCALED_PACK32`, `VK_FORMAT_A2B10G10R10_SSCALED_PACK32`, `VK_FORMAT_A2B10G10R10_UINT_PACK32`, `VK_FORMAT_A2B10G10R10_SINT_PACK32`, `VK_FORMAT_R16G16_UNORM`, `VK_FORMAT_R16G16_SNORM`, `VK_FORMAT_R16G16_USCALED`, `VK_FORMAT_R16G16_SSCALED`, `VK_FORMAT_R16G16_UINT`, `VK_FORMAT_R16G16_SINT`, `VK_FORMAT_R16G16_SFLOAT`, `VK_FORMAT_R32_UINT`, `VK_FORMAT_R32_SINT`, `VK_FORMAT_R32_SFLOAT`, `VK_FORMAT_B10G11R11_UFLOAT_PACK32`, `VK_FORMAT_E5B9G9R9_UFLOAT_PACK32`, `VK_FORMAT_R10X6G10X6_UNORM_2PACK16`, `VK_FORMAT_R12X4G12X4_UNORM_2PACK16`
32-bit G8B8G8R8 Block size 4 bytes 1 texel/block | `VK_FORMAT_G8B8G8R8_422_UNORM`
32-bit B8G8R8G8 Block size 4 bytes 1 texel/block | `VK_FORMAT_B8G8R8G8_422_UNORM`
48-bit Block size 6 bytes 1 texel/block | `VK_FORMAT_R16G16B16_UNORM`, `VK_FORMAT_R16G16B16_SNORM`, `VK_FORMAT_R16G16B16_USCALED`, `VK_FORMAT_R16G16B16_SSCALED`, `VK_FORMAT_R16G16B16_UINT`, `VK_FORMAT_R16G16B16_SINT`, `VK_FORMAT_R16G16B16_SFLOAT`
64-bit Block size 8 bytes 1 texel/block | `VK_FORMAT_R16G16B16A16_UNORM`, `VK_FORMAT_R16G16B16A16_SNORM`, `VK_FORMAT_R16G16B16A16_USCALED`, `VK_FORMAT_R16G16B16A16_SSCALED`, `VK_FORMAT_R16G16B16A16_UINT`, `VK_FORMAT_R16G16B16A16_SINT`, `VK_FORMAT_R16G16B16A16_SFLOAT`, `VK_FORMAT_R32G32_UINT`, `VK_FORMAT_R32G32_SINT`, `VK_FORMAT_R32G32_SFLOAT`, `VK_FORMAT_R64_UINT`, `VK_FORMAT_R64_SINT`, `VK_FORMAT_R64_SFLOAT`
64-bit R10G10B10A10 Block size 8 bytes 1 texel/block | `VK_FORMAT_R10X6G10X6B10X6A10X6_UNORM_4PACK16`
64-bit G10B10G10R10 Block size 8 bytes 1 texel/block | `VK_FORMAT_G10X6B10X6G10X6R10X6_422_UNORM_4PACK16`
64-bit B10G10R10G10 Block size 8 bytes 1 texel/block | `VK_FORMAT_B10X6G10X6R10X6G10X6_422_UNORM_4PACK16`
64-bit R12G12B12A12 Block size 8 bytes 1 texel/block | `VK_FORMAT_R12X4G12X4B12X4A12X4_UNORM_4PACK16`
64-bit G12B12G12R12 Block size 8 bytes 1 texel/block | `VK_FORMAT_G12X4B12X4G12X4R12X4_422_UNORM_4PACK16`
64-bit B12G12R12G12 Block size 8 bytes 1 texel/block | `VK_FORMAT_B12X4G12X4R12X4G12X4_422_UNORM_4PACK16`
64-bit G16B16G16R16 Block size 8 bytes 1 texel/block | `VK_FORMAT_G16B16G16R16_422_UNORM`
64-bit B16G16R16G16 Block size 8 bytes 1 texel/block | `VK_FORMAT_B16G16R16G16_422_UNORM`
96-bit Block size 12 bytes 1 texel/block | `VK_FORMAT_R32G32B32_UINT`, `VK_FORMAT_R32G32B32_SINT`, `VK_FORMAT_R32G32B32_SFLOAT`
128-bit Block size 16 bytes 1 texel/block | `VK_FORMAT_R32G32B32A32_UINT`, `VK_FORMAT_R32G32B32A32_SINT`, `VK_FORMAT_R32G32B32A32_SFLOAT`, `VK_FORMAT_R64G64_UINT`, `VK_FORMAT_R64G64_SINT`, `VK_FORMAT_R64G64_SFLOAT`
192-bit Block size 24 bytes 1 texel/block | `VK_FORMAT_R64G64B64_UINT`, `VK_FORMAT_R64G64B64_SINT`, `VK_FORMAT_R64G64B64_SFLOAT`
256-bit Block size 32 bytes 1 texel/block | `VK_FORMAT_R64G64B64A64_UINT`, `VK_FORMAT_R64G64B64A64_SINT`, `VK_FORMAT_R64G64B64A64_SFLOAT`
BC1_RGB (64 bit) Block size 8 bytes 16 texels/block | `VK_FORMAT_BC1_RGB_UNORM_BLOCK`, `VK_FORMAT_BC1_RGB_SRGB_BLOCK`
BC1_RGBA (64 bit) Block size 8 bytes 16 texels/block | `VK_FORMAT_BC1_RGBA_UNORM_BLOCK`, `VK_FORMAT_BC1_RGBA_SRGB_BLOCK`
BC2 (128 bit) Block size 16 bytes 16 texels/block | `VK_FORMAT_BC2_UNORM_BLOCK`, `VK_FORMAT_BC2_SRGB_BLOCK`
BC3 (128 bit) Block size 16 bytes 16 texels/block | `VK_FORMAT_BC3_UNORM_BLOCK`, `VK_FORMAT_BC3_SRGB_BLOCK`
BC4 (64 bit) Block size 8 bytes 16 texels/block | `VK_FORMAT_BC4_UNORM_BLOCK`, `VK_FORMAT_BC4_SNORM_BLOCK`
BC5 (128 bit) Block size 16 bytes 16 texels/block | `VK_FORMAT_BC5_UNORM_BLOCK`, `VK_FORMAT_BC5_SNORM_BLOCK`
BC6H (128 bit) Block size 16 bytes 16 texels/block | `VK_FORMAT_BC6H_UFLOAT_BLOCK`, `VK_FORMAT_BC6H_SFLOAT_BLOCK`
BC7 (128 bit) Block size 16 bytes 16 texels/block | `VK_FORMAT_BC7_UNORM_BLOCK`, `VK_FORMAT_BC7_SRGB_BLOCK`
ETC2_RGB (64 bit) Block size 8 bytes 16 texels/block | `VK_FORMAT_ETC2_R8G8B8_UNORM_BLOCK`, `VK_FORMAT_ETC2_R8G8B8_SRGB_BLOCK`
ETC2_RGBA (64 bit) Block size 8 bytes 16 texels/block | `VK_FORMAT_ETC2_R8G8B8A1_UNORM_BLOCK`, `VK_FORMAT_ETC2_R8G8B8A1_SRGB_BLOCK`
ETC2_EAC_RGBA (64 bit) Block size 8 bytes 16 texels/block | `VK_FORMAT_ETC2_R8G8B8A8_UNORM_BLOCK`, `VK_FORMAT_ETC2_R8G8B8A8_SRGB_BLOCK`
EAC_R (64 bit) Block size 8 bytes 16 texels/block | `VK_FORMAT_EAC_R11_UNORM_BLOCK`, `VK_FORMAT_EAC_R11_SNORM_BLOCK`
EAC_RG (128 bit) Block size 16 bytes 16 texels/block | `VK_FORMAT_EAC_R11G11_UNORM_BLOCK`, `VK_FORMAT_EAC_R11G11_SNORM_BLOCK`
ASTC_4x4 (128 bit) Block size 16 bytes 16 texels/block | `VK_FORMAT_ASTC_4x4_UNORM_BLOCK`, `VK_FORMAT_ASTC_4x4_SFLOAT_BLOCK_EXT`, `VK_FORMAT_ASTC_4x4_SRGB_BLOCK`
ASTC_5x4 (128 bit) Block size 16 bytes 20 texels/block | `VK_FORMAT_ASTC_5x4_UNORM_BLOCK`, `VK_FORMAT_ASTC_5x4_SFLOAT_BLOCK_EXT`, `VK_FORMAT_ASTC_5x4_SRGB_BLOCK`
ASTC_5x5 (128 bit) Block size 16 bytes 25 texels/block | `VK_FORMAT_ASTC_5x5_UNORM_BLOCK`, `VK_FORMAT_ASTC_5x5_SFLOAT_BLOCK_EXT`, `VK_FORMAT_ASTC_5x5_SRGB_BLOCK`
ASTC_6x5 (128 bit) Block size 16 bytes 30 texels/block | `VK_FORMAT_ASTC_6x5_UNORM_BLOCK`, `VK_FORMAT_ASTC_6x5_SFLOAT_BLOCK_EXT`, `VK_FORMAT_ASTC_6x5_SRGB_BLOCK`
ASTC_6x6 (128 bit) Block size 16 bytes 36 texels/block | `VK_FORMAT_ASTC_6x6_UNORM_BLOCK`, `VK_FORMAT_ASTC_6x6_SFLOAT_BLOCK_EXT`, `VK_FORMAT_ASTC_6x6_SRGB_BLOCK`
ASTC_8x5 (128 bit) Block size 16 bytes 40 texels/block | `VK_FORMAT_ASTC_8x5_UNORM_BLOCK`, `VK_FORMAT_ASTC_8x5_SFLOAT_BLOCK_EXT`, `VK_FORMAT_ASTC_8x5_SRGB_BLOCK`
ASTC_8x6 (128 bit) Block size 16 bytes 48 texels/block | `VK_FORMAT_ASTC_8x6_UNORM_BLOCK`, `VK_FORMAT_ASTC_8x6_SFLOAT_BLOCK_EXT`, `VK_FORMAT_ASTC_8x6_SRGB_BLOCK`
ASTC_8x8 (128 bit) Block size 16 bytes 64 texels/block | `VK_FORMAT_ASTC_8x8_UNORM_BLOCK`, `VK_FORMAT_ASTC_8x8_SFLOAT_BLOCK_EXT`, `VK_FORMAT_ASTC_8x8_SRGB_BLOCK`
ASTC_10x5 (128 bit) Block size 16 bytes 50 texels/block | `VK_FORMAT_ASTC_10x5_UNORM_BLOCK`, `VK_FORMAT_ASTC_10x5_SFLOAT_BLOCK_EXT`, `VK_FORMAT_ASTC_10x5_SRGB_BLOCK`
ASTC_10x6 (128 bit) Block size 16 bytes 60 texels/block | `VK_FORMAT_ASTC_10x6_UNORM_BLOCK`, `VK_FORMAT_ASTC_10x6_SFLOAT_BLOCK_EXT`, `VK_FORMAT_ASTC_10x6_SRGB_BLOCK`
ASTC_10x8 (128 bit) Block size 16 bytes 80 texels/block | `VK_FORMAT_ASTC_10x8_UNORM_BLOCK`, `VK_FORMAT_ASTC_10x8_SFLOAT_BLOCK_EXT`, `VK_FORMAT_ASTC_10x8_SRGB_BLOCK`
ASTC_10x10 (128 bit) Block size 16 bytes 100 texels/block | `VK_FORMAT_ASTC_10x10_UNORM_BLOCK`, `VK_FORMAT_ASTC_10x10_SFLOAT_BLOCK_EXT`, `VK_FORMAT_ASTC_10x10_SRGB_BLOCK`
ASTC_12x10 (128 bit) Block size 16 bytes 120 texels/block | `VK_FORMAT_ASTC_12x10_UNORM_BLOCK`, `VK_FORMAT_ASTC_12x10_SFLOAT_BLOCK_EXT`, `VK_FORMAT_ASTC_12x10_SRGB_BLOCK`
ASTC_12x12 (128 bit) Block size 16 bytes 144 texels/block | `VK_FORMAT_ASTC_12x12_UNORM_BLOCK`, `VK_FORMAT_ASTC_12x12_SFLOAT_BLOCK_EXT`, `VK_FORMAT_ASTC_12x12_SRGB_BLOCK`
D16 (16 bit) Block size 2 bytes 1 texel/block | `VK_FORMAT_D16_UNORM`
D24 (32 bit) Block size 4 bytes 1 texel/block | `VK_FORMAT_X8_D24_UNORM_PACK32`
D32 (32 bit) Block size 4 bytes 1 texel/block | `VK_FORMAT_D32_SFLOAT`
S8 (8 bit) Block size 1 byte 1 texel/block | `VK_FORMAT_S8_UINT`
D16S8 (24 bit) Block size 3 bytes 1 texel/block | `VK_FORMAT_D16_UNORM_S8_UINT`
D24S8 (32 bit) Block size 4 bytes 1 texel/block | `VK_FORMAT_D24_UNORM_S8_UINT`
D32S8 (40 bit) Block size 5 bytes 1 texel/block | `VK_FORMAT_D32_SFLOAT_S8_UINT`
8-bit 3-plane 420 Block size (1,1,1) bytes 1 texel/block | `VK_FORMAT_G8_B8_R8_3PLANE_420_UNORM`
8-bit 2-plane 420 Block size (1,2) bytes 1 texel/block | `VK_FORMAT_G8_B8R8_2PLANE_420_UNORM`
8-bit 3-plane 422 Block size (1,1,1) bytes 1 texel/block | `VK_FORMAT_G8_B8_R8_3PLANE_422_UNORM`
8-bit 2-plane 422 Block size (1,2) bytes 1 texel/block | `VK_FORMAT_G8_B8R8_2PLANE_422_UNORM`
8-bit 3-plane 444 Block size (1,1,1) bytes 1 texel/block | `VK_FORMAT_G8_B8_R8_3PLANE_444_UNORM`
10-bit 3-plane 420 Block size (2,2,2) bytes 1 texel/block | `VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_420_UNORM_3PACK16`
10-bit 2-plane 420 Block size (2,4) bytes 1 texel/block | `VK_FORMAT_G10X6_B10X6R10X6_2PLANE_420_UNORM_3PACK16`
10-bit 3-plane 422 Block size (2,2,2) bytes 1 texel/block | `VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_422_UNORM_3PACK16`
10-bit 2-plane 422 Block size (2,2) bytes 1 texel/block | `VK_FORMAT_G10X6_B10X6R10X6_2PLANE_422_UNORM_3PACK16`
10-bit 3-plane 444 Block size (2,2,2) bytes 1 texel/block | `VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_444_UNORM_3PACK16`
12-bit 3-plane 420 Block size (2,2,2) bytes 1 texel/block | `VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_420_UNORM_3PACK16`
12-bit 2-plane 420 Block size (2,4) bytes 1 texel/block | `VK_FORMAT_G12X4_B12X4R12X4_2PLANE_420_UNORM_3PACK16`
12-bit 3-plane 422 Block size (2,2,2) bytes 1 texel/block | `VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_422_UNORM_3PACK16`
12-bit 2-plane 422 Block size (2,4) bytes 1 texel/block | `VK_FORMAT_G12X4_B12X4R12X4_2PLANE_422_UNORM_3PACK16`
12-bit 3-plane 444 Block size (2,2,2) bytes 1 texel/block | `VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_444_UNORM_3PACK16`
16-bit 3-plane 420 Block size (2,2,2) bytes 1 texel/block | `VK_FORMAT_G16_B16_R16_3PLANE_420_UNORM`
16-bit 2-plane 420 Block size (2,4) bytes 1 texel/block | `VK_FORMAT_G16_B16R16_2PLANE_420_UNORM`
16-bit 3-plane 422 Block size (2,2,2) bytes 1 texel/block | `VK_FORMAT_G16_B16_R16_3PLANE_422_UNORM`
16-bit 2-plane 422 Block size (2,4) bytes 1 texel/block | `VK_FORMAT_G16_B16R16_2PLANE_422_UNORM`
16-bit 3-plane 444 Block size (2,2,2) bytes 1 texel/block | `VK_FORMAT_G16_B16_R16_3PLANE_444_UNORM`

### 39.2. Format Properties

To query supported format features which are properties of the physical device, call:

    void vkGetPhysicalDeviceFormatProperties(
        VkPhysicalDevice                            physicalDevice,
        VkFormat                                    format,
        VkFormatProperties*                         pFormatProperties);

- `physicalDevice` is the physical device from which to query the format properties.

- `format` is the format whose properties are queried.

- `pFormatProperties` is a pointer to a VkFormatProperties structure in which physical device properties for `format` are returned.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `format` must be a valid VkFormat value

- `pFormatProperties` must be a valid pointer to a VkFormatProperties structure

The `VkFormatProperties` structure is defined as:

    typedef struct VkFormatProperties {
        VkFormatFeatureFlags    linearTilingFeatures;
        VkFormatFeatureFlags    optimalTilingFeatures;
        VkFormatFeatureFlags    bufferFeatures;
    } VkFormatProperties;

- `linearTilingFeatures` is a bitmask of VkFormatFeatureFlagBits specifying features supported by images created with a `tiling` parameter of `VK_IMAGE_TILING_LINEAR`.

- `optimalTilingFeatures` is a bitmask of VkFormatFeatureFlagBits specifying features supported by images created with a `tiling` parameter of `VK_IMAGE_TILING_OPTIMAL`.

- `bufferFeatures` is a bitmask of VkFormatFeatureFlagBits specifying features supported by buffers.

| Note If no format feature flags are supported, the format itself is not supported, and images of that format cannot be created.

If `format` is a block-compressed format, then `bufferFeatures` must not support any features for the format.

If `format` is not a multi-plane format then `linearTilingFeatures` and `optimalTilingFeatures` must not contain `VK_FORMAT_FEATURE_DISJOINT_BIT`.

Bits which can be set in the VkFormatProperties features `linearTilingFeatures`, `optimalTilingFeatures`, `drmFormatModifierTilingFeatures`, and `bufferFeatures` are:

    typedef enum VkFormatFeatureFlagBits {
        VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT = 0x00000001,
        VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT = 0x00000002,
        VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT = 0x00000004,
        VK_FORMAT_FEATURE_UNIFORM_TEXEL_BUFFER_BIT = 0x00000008,
        VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_BIT = 0x00000010,
        VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_ATOMIC_BIT = 0x00000020,
        VK_FORMAT_FEATURE_VERTEX_BUFFER_BIT = 0x00000040,
        VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT = 0x00000080,
        VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BLEND_BIT = 0x00000100,
        VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT = 0x00000200,
        VK_FORMAT_FEATURE_BLIT_SRC_BIT = 0x00000400,
        VK_FORMAT_FEATURE_BLIT_DST_BIT = 0x00000800,
        VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT = 0x00001000,
        VK_FORMAT_FEATURE_TRANSFER_SRC_BIT = 0x00004000,
        VK_FORMAT_FEATURE_TRANSFER_DST_BIT = 0x00008000,
        VK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BIT = 0x00020000,
        VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_LINEAR_FILTER_BIT = 0x00040000,
        VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_SEPARATE_RECONSTRUCTION_FILTER_BIT = 0x00080000,
        VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_BIT = 0x00100000,
        VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_FORCEABLE_BIT = 0x00200000,
        VK_FORMAT_FEATURE_DISJOINT_BIT = 0x00400000,
        VK_FORMAT_FEATURE_COSITED_CHROMA_SAMPLES_BIT = 0x00800000,
        VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_MINMAX_BIT = 0x00010000,
        VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_IMG = 0x00002000,
        VK_FORMAT_FEATURE_ACCELERATION_STRUCTURE_VERTEX_BUFFER_BIT_KHR = 0x20000000,
        VK_FORMAT_FEATURE_FRAGMENT_DENSITY_MAP_BIT_EXT = 0x01000000,
        VK_FORMAT_FEATURE_TRANSFER_SRC_BIT_KHR = VK_FORMAT_FEATURE_TRANSFER_SRC_BIT,
        VK_FORMAT_FEATURE_TRANSFER_DST_BIT_KHR = VK_FORMAT_FEATURE_TRANSFER_DST_BIT,
        VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_MINMAX_BIT_EXT = VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_MINMAX_BIT,
        VK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BIT_KHR = VK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BIT,
        VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_LINEAR_FILTER_BIT_KHR = VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_LINEAR_FILTER_BIT,
        VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_SEPARATE_RECONSTRUCTION_FILTER_BIT_KHR = VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_SEPARATE_RECONSTRUCTION_FILTER_BIT,
        VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_BIT_KHR = VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_BIT,
        VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_FORCEABLE_BIT_KHR = VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_FORCEABLE_BIT,
        VK_FORMAT_FEATURE_DISJOINT_BIT_KHR = VK_FORMAT_FEATURE_DISJOINT_BIT,
        VK_FORMAT_FEATURE_COSITED_CHROMA_SAMPLES_BIT_KHR = VK_FORMAT_FEATURE_COSITED_CHROMA_SAMPLES_BIT,
        VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_EXT = VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_IMG,
        VK_FORMAT_FEATURE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkFormatFeatureFlagBits;

The following bits may be set in `linearTilingFeatures`, `optimalTilingFeatures`, and `drmFormatModifierTilingFeatures`, specifying that the features are supported by images or image views created with the queried vkGetPhysicalDeviceFormatProperties::`format`:

- `VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT` specifies that an image view can be sampled from.

- `VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT` specifies that an image view can be used as a storage images.

- `VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT` specifies that an image view can be used as storage image that supports atomic operations.

- `VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT` specifies that an image view can be used as a framebuffer color attachment and as an input attachment.

- `VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BLEND_BIT` specifies that an image view can be used as a framebuffer color attachment that supports blending and as an input attachment.

- `VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT` specifies that an image view can be used as a framebuffer depth/stencil attachment and as an input attachment.

- `VK_FORMAT_FEATURE_BLIT_SRC_BIT` specifies that an image can be used as `srcImage` for the `vkCmdBlitImage` command.

- `VK_FORMAT_FEATURE_BLIT_DST_BIT` specifies that an image can be used as `dstImage` for the `vkCmdBlitImage` command.

- `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT` specifies that if `VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT` is also set, an image view can be used with a sampler that has either of `magFilter` or `minFilter` set to `VK_FILTER_LINEAR`, or `mipmapMode` set to `VK_SAMPLER_MIPMAP_MODE_LINEAR`. If `VK_FORMAT_FEATURE_BLIT_SRC_BIT` is also set, an image can be used as the `srcImage` to vkCmdBlitImage with a `filter` of `VK_FILTER_LINEAR`. This bit must only be exposed for formats that also support the `VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT` or `VK_FORMAT_FEATURE_BLIT_SRC_BIT`.

  If the format being queried is a depth/stencil format, this bit only specifies that the depth aspect (not the stencil aspect) of an image of this format supports linear filtering, and that linear filtering of the depth aspect is supported whether depth compare is enabled in the sampler or not. If this bit is not present, linear filtering with depth compare disabled is unsupported and linear filtering with depth compare enabled is supported, but may compute the filtered value in an implementation-dependent manner which differs from the normal rules of linear filtering. The resulting value must be in the range [0,1] and should be proportional to, or a weighted average of, the number of comparison passes or failures.

- `VK_FORMAT_FEATURE_TRANSFER_SRC_BIT` specifies that an image can be used as a source image for copy commands.

- `VK_FORMAT_FEATURE_TRANSFER_DST_BIT` specifies that an image can be used as a destination image for copy commands and clear commands.

- `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_MINMAX_BIT` specifies `VkImage` can be used as a sampled image with a min or max VkSamplerReductionMode. This bit must only be exposed for formats that also support the `VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT`.

- `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_EXT` specifies that `VkImage` can be used with a sampler that has either of `magFilter` or `minFilter` set to `VK_FILTER_CUBIC_EXT`, or be the source image for a blit with `filter` set to `VK_FILTER_CUBIC_EXT`. This bit must only be exposed for formats that also support the `VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT`. If the format being queried is a depth/stencil format, this only specifies that the depth aspect is cubic filterable.

- `VK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BIT` specifies that an application can define a sampler Y′CBCR conversion using this format as a source, and that an image of this format can be used with a `VkSamplerYcbcrConversionCreateInfo` `xChromaOffset` and/or `yChromaOffset` of `VK_CHROMA_LOCATION_MIDPOINT`. Otherwise both `xChromaOffset` and `yChromaOffset` must be `VK_CHROMA_LOCATION_COSITED_EVEN`. If a format does not incorporate chroma downsampling (it is not a “422” or “420” format) but the implementation supports sampler Y′CBCR conversion for this format, the implementation must set `VK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BIT`.

- `VK_FORMAT_FEATURE_COSITED_CHROMA_SAMPLES_BIT` specifies that an application can define a sampler Y′CBCR conversion using this format as a source, and that an image of this format can be used with a `VkSamplerYcbcrConversionCreateInfo` `xChromaOffset` and/or `yChromaOffset` of `VK_CHROMA_LOCATION_COSITED_EVEN`. Otherwise both `xChromaOffset` and `yChromaOffset` must be `VK_CHROMA_LOCATION_MIDPOINT`. If neither `VK_FORMAT_FEATURE_COSITED_CHROMA_SAMPLES_BIT` nor `VK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BIT` is set, the application must not define a sampler Y′CBCR conversion using this format as a source.

- `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_LINEAR_FILTER_BIT` specifies that the format can do linear sampler filtering (min/magFilter) whilst sampler Y′CBCR conversion is enabled.

- `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_SEPARATE_RECONSTRUCTION_FILTER_BIT` specifies that the format can have different chroma, min, and mag filters.

- `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_BIT` specifies that reconstruction is explicit, as described in Chroma Reconstruction. If this bit is not present, reconstruction is implicit by default.

- `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_FORCEABLE_BIT` specifies that reconstruction can be forcibly made explicit by setting VkSamplerYcbcrConversionCreateInfo::`forceExplicitReconstruction` to `VK_TRUE`. If the format being queried supports `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_BIT` it must also support `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_FORCEABLE_BIT`.

- `VK_FORMAT_FEATURE_DISJOINT_BIT` specifies that a multi-planar image can have the `VK_IMAGE_CREATE_DISJOINT_BIT` set during image creation. An implementation must not set `VK_FORMAT_FEATURE_DISJOINT_BIT` for single-plane formats.

- `VK_FORMAT_FEATURE_FRAGMENT_DENSITY_MAP_BIT_EXT` specifies that an image view can be used as a fragment density map attachment.

The following bits may be set in `bufferFeatures`, specifying that the features are supported by buffers or buffer views created with the queried vkGetPhysicalDeviceProperties::`format`:

- `VK_FORMAT_FEATURE_UNIFORM_TEXEL_BUFFER_BIT` specifies that the format can be used to create a buffer view that can be bound to a `VK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER` descriptor.

- `VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_BIT` specifies that the format can be used to create a buffer view that can be bound to a `VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER` descriptor.

- `VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_ATOMIC_BIT` specifies that atomic operations are supported on `VK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER` with this format.

- `VK_FORMAT_FEATURE_VERTEX_BUFFER_BIT` specifies that the format can be used as a vertex attribute format (`VkVertexInputAttributeDescription`::`format`).

    typedef VkFlags VkFormatFeatureFlags;

`VkFormatFeatureFlags` is a bitmask type for setting a mask of zero or more VkFormatFeatureFlagBits.

To query supported format features which are properties of the physical device, call:

    void vkGetPhysicalDeviceFormatProperties2(
        VkPhysicalDevice                            physicalDevice,
        VkFormat                                    format,
        VkFormatProperties2*                        pFormatProperties);

or the equivalent command

    void vkGetPhysicalDeviceFormatProperties2KHR(
        VkPhysicalDevice                            physicalDevice,
        VkFormat                                    format,
        VkFormatProperties2*                        pFormatProperties);

- `physicalDevice` is the physical device from which to query the format properties.

- `format` is the format whose properties are queried.

- `pFormatProperties` is a pointer to a VkFormatProperties2 structure in which physical device properties for `format` are returned.

`vkGetPhysicalDeviceFormatProperties2` behaves similarly to vkGetPhysicalDeviceFormatProperties, with the ability to return extended information in a `pNext` chain of output structures.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `format` must be a valid VkFormat value

- `pFormatProperties` must be a valid pointer to a VkFormatProperties2 structure

The `VkFormatProperties2` structure is defined as:

    typedef struct VkFormatProperties2 {
        VkStructureType       sType;
        void*                 pNext;
        VkFormatProperties    formatProperties;
    } VkFormatProperties2;

or the equivalent

    typedef VkFormatProperties2 VkFormatProperties2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `formatProperties` is a VkFormatProperties structure describing features supported by the requested format.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_FORMAT_PROPERTIES_2`

- `pNext` must be `NULL` or a pointer to a valid instance of VkDrmFormatModifierPropertiesListEXT

- The `sType` value of each struct in the `pNext` chain must be unique

To obtain the list of Linux DRM format modifiers compatible with a VkFormat, add a VkDrmFormatModifierPropertiesListEXT structure to the `pNext` chain of VkFormatProperties2.

The VkDrmFormatModifierPropertiesListEXT structure is defined as:

    typedef struct VkDrmFormatModifierPropertiesListEXT {
        VkStructureType                      sType;
        void*                                pNext;
        uint32_t                             drmFormatModifierCount;
        VkDrmFormatModifierPropertiesEXT*    pDrmFormatModifierProperties;
    } VkDrmFormatModifierPropertiesListEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `drmFormatModifierCount` is an inout parameter related to the number of modifiers compatible with the `format`, as described below.

- `pDrmFormatModifierProperties` is either `NULL` or an array of VkDrmFormatModifierPropertiesEXT structures.

If `pDrmFormatModifierProperties` is `NULL`, then the function returns in `drmFormatModifierCount` the number of modifiers compatible with the queried `format`. Otherwise, the application must set `drmFormatModifierCount` to the length of the array `pDrmFormatModifierProperties`; the function will write at most `drmFormatModifierCount` elements to the array, and will return in `drmFormatModifierCount` the number of elements written.

Among the elements in array `pDrmFormatModifierProperties`, each returned `drmFormatModifier` must be unique.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DRM_FORMAT_MODIFIER_PROPERTIES_LIST_EXT`

The VkDrmFormatModifierPropertiesEXT structure describes properties of a VkFormat when that format is combined with a Linux DRM format modifier. These properties, like those of VkFormatProperties2, are independent of any particular image.

The VkDrmFormatModifierPropertiesEXT structure is defined as:

    typedef struct VkDrmFormatModifierPropertiesEXT {
        uint64_t                drmFormatModifier;
        uint32_t                drmFormatModifierPlaneCount;
        VkFormatFeatureFlags    drmFormatModifierTilingFeatures;
    } VkDrmFormatModifierPropertiesEXT;

- `drmFormatModifier` is a Linux DRM format modifier.

- `drmFormatModifierPlaneCount` is the number of memory planes in any image created with `format` and `drmFormatModifier`. An image’s memory planecount is distinct from its format planecount, as explained below.

- `drmFormatModifierTilingFeatures` is a bitmask of VkFormatFeatureFlagBits that are supported by any image created with `format` and `drmFormatModifier`.

The returned `drmFormatModifierTilingFeatures` must contain at least one bit.

The implementation must not return `DRM_FORMAT_MOD_INVALID` in `drmFormatModifier`.

An image’s memory planecount (as returned by `drmFormatModifierPlaneCount`) is distinct from its format planecount (in the sense of multi-planar Y′CBCR formats). In VkImageAspectFlags, each `VK_IMAGE_ASPECT_MEMORY_PLANE` i_BIT_EXT represents a _memory plane and each `VK_IMAGE_ASPECT_PLANE` i_BIT a _format plane.

An image’s set of format planes is an ordered partition of the image’s content into separable groups of format channels. The ordered partition is encoded in the name of each VkFormat. For example, `VK_FORMAT_G8_B8R8_2PLANE_420_UNORM` contains two format planes; the first plane contains the green channel and the second plane contains the blue channel and red channel. If the format name does not contain `PLANE`, then the format contains a single plane; for example, `VK_FORMAT_R8G8B8A8_UNORM`. Some commands, such as vkCmdCopyBufferToImage, do not operate on all format channels in the image, but instead operate only on the format planes explicitly chosen by the application and operate on each format plane independently.

An image’s set of memory planes is an ordered partition of the image’s memory rather than the image’s content. Each memory plane is a contiguous range of memory. The union of an image’s memory planes is not necessarily contiguous.

If an image is linear, then the partition is the same for memory planes and for format planes. Therefore, if the returned `drmFormatModifier` is `DRM_FORMAT_MOD_LINEAR`, then `drmFormatModifierPlaneCount` must equal the format planecount, and `drmFormatModifierTilingFeatures` must be identical to the VkFormatProperties2::`linearTilingFeatures` returned in the same `pNext` chain.

If an image is non-linear, then the partition of the image’s memory into memory planes is implementation-specific and may be unrelated to the partition of the image’s content into format planes. For example, consider an image whose `format` is `VK_FORMAT_G8_B8_R8_3PLANE_420_UNORM`, `tiling` is `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`, whose `drmFormatModifier` is not `DRM_FORMAT_MOD_LINEAR`, and `flags` lacks `VK_IMAGE_CREATE_DISJOINT_BIT`. The image has 3 format planes, and commands such vkCmdCopyBufferToImage act on each format plane independently as if the data of each format plane were separable from the data of the other planes. In a straightforward implementation, the implementation may store the image’s content in 3 adjacent memory planes where each memory plane corresponds exactly to a format plane. However, the implementation may also store the image’s content in a single memory plane where all format channels are combined using an implementation-private block-compressed format; or the implementation may store the image’s content in a collection of 7 adjacent memory planes using an implementation-private sharding technique. Because the image is non-linear and non-disjoint, the implementation has much freedom when choosing the image’s placement in memory.

The memory planecount applies to function parameters and structures only when the API specifies an explicit requirement on `drmFormatModifierPlaneCount`. In all other cases, the memory planecount is ignored.

### 39.3. Required Format Support

Implementations must support at least the following set of features on the listed formats. For images, these features must be supported for every VkImageType (including arrayed and cube variants) unless otherwise noted. These features are supported on existing formats without needing to advertise an extension or needing to explicitly enable them. Support for additional functionality beyond the requirements listed here is queried using the vkGetPhysicalDeviceFormatProperties command.

| Note Unless otherwise excluded below, the required formats are supported for all VkImageCreateFlags values as long as those flag values are otherwise allowed.

The following tables show which feature bits must be supported for each format. Formats that are required to support `VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT` must also support `VK_FORMAT_FEATURE_TRANSFER_SRC_BIT` and `VK_FORMAT_FEATURE_TRANSFER_DST_BIT`.

Table 55. Key for format feature tables
✓ | This feature must be supported on the named format
† | This feature must be supported on at least some of the named formats, with more information in the table where the symbol appears
‡ | This feature must be supported with some caveats or preconditions, with more information in the table where the symbol appears

Table 56. Feature bits in `optimalTilingFeatures`
`VK_FORMAT_FEATURE_TRANSFER_SRC_BIT`
`VK_FORMAT_FEATURE_TRANSFER_DST_BIT`
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT`
`VK_FORMAT_FEATURE_BLIT_SRC_BIT`
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT`
`VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT`
`VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT`
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT`
`VK_FORMAT_FEATURE_BLIT_DST_BIT`
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BLEND_BIT`
`VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT`
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_MINMAX_BIT`

Table 57. Feature bits in `bufferFeatures`
`VK_FORMAT_FEATURE_VERTEX_BUFFER_BIT`
`VK_FORMAT_FEATURE_UNIFORM_TEXEL_BUFFER_BIT`
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_BIT`
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_ATOMIC_BIT`

Table 58. Mandatory format support: sub-byte channels
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_ATOMIC_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_UNIFORM_TEXEL_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_VERTEX_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT` | ↓
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BLEND_BIT` | ↓
`VK_FORMAT_FEATURE_BLIT_DST_BIT` | ↓
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT` | ↓
`VK_FORMAT_FEATURE_BLIT_SRC_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT` | ↓
Format
`VK_FORMAT_UNDEFINED` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R4G4_UNORM_PACK8` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R4G4B4A4_UNORM_PACK16` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_B4G4R4A4_UNORM_PACK16` | ✓ | ✓ | ✓ |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R5G6B5_UNORM_PACK16` | ✓ | ✓ | ✓ |  |  | ✓ | ✓ | ✓ |  |  |  |  |
`VK_FORMAT_B5G6R5_UNORM_PACK16` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R5G5B5A1_UNORM_PACK16` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_B5G5R5A1_UNORM_PACK16` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_A1R5G5B5_UNORM_PACK16` | ✓ | ✓ | ✓ |  |  | ✓ | ✓ | ✓ |  |  |  |  |

Table 59. Mandatory format support: 1-3 byte-sized channels
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_ATOMIC_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_UNIFORM_TEXEL_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_VERTEX_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT` | ↓
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BLEND_BIT` | ↓
`VK_FORMAT_FEATURE_BLIT_DST_BIT` | ↓
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT` | ↓
`VK_FORMAT_FEATURE_BLIT_SRC_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT` | ↓
Format
`VK_FORMAT_R8_UNORM` | ✓ | ✓ | ✓ | ‡ |  | ✓ | ✓ | ✓ |  | ✓ | ✓ |  |
`VK_FORMAT_R8_SNORM` | ✓ | ✓ | ✓ | ‡ |  |  |  |  |  | ✓ | ✓ |  |
`VK_FORMAT_R8_USCALED` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R8_SSCALED` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R8_UINT` | ✓ | ✓ |  | ‡ |  | ✓ | ✓ |  |  | ✓ | ✓ |  |
`VK_FORMAT_R8_SINT` | ✓ | ✓ |  | ‡ |  | ✓ | ✓ |  |  | ✓ | ✓ |  |
`VK_FORMAT_R8_SRGB` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R8G8_UNORM` | ✓ | ✓ | ✓ | ‡ |  | ✓ | ✓ | ✓ |  | ✓ | ✓ |  |
`VK_FORMAT_R8G8_SNORM` | ✓ | ✓ | ✓ | ‡ |  |  |  |  |  | ✓ | ✓ |  |
`VK_FORMAT_R8G8_USCALED` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R8G8_SSCALED` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R8G8_UINT` | ✓ | ✓ |  | ‡ |  | ✓ | ✓ |  |  | ✓ | ✓ |  |
`VK_FORMAT_R8G8_SINT` | ✓ | ✓ |  | ‡ |  | ✓ | ✓ |  |  | ✓ | ✓ |  |
`VK_FORMAT_R8G8_SRGB` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R8G8B8_UNORM` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R8G8B8_SNORM` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R8G8B8_USCALED` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R8G8B8_SSCALED` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R8G8B8_UINT` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R8G8B8_SINT` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R8G8B8_SRGB` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_B8G8R8_UNORM` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_B8G8R8_SNORM` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_B8G8R8_USCALED` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_B8G8R8_SSCALED` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_B8G8R8_UINT` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_B8G8R8_SINT` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_B8G8R8_SRGB` |  |  |  |  |  |  |  |  |  |  |  |  |
Format features marked with ‡ must be supported for `optimalTilingFeatures` if the `VkPhysicalDevice` supports the `shaderStorageImageExtendedFormats` feature.

Table 60. Mandatory format support: 4 byte-sized channels
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_ATOMIC_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_UNIFORM_TEXEL_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_VERTEX_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT` | ↓
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BLEND_BIT` | ↓
`VK_FORMAT_FEATURE_BLIT_DST_BIT` | ↓
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT` | ↓
`VK_FORMAT_FEATURE_BLIT_SRC_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT` | ↓
Format
`VK_FORMAT_R8G8B8A8_UNORM` | ✓ | ✓ | ✓ | ✓ |  | ✓ | ✓ | ✓ |  | ✓ | ✓ | ✓ |
`VK_FORMAT_R8G8B8A8_SNORM` | ✓ | ✓ | ✓ | ✓ |  |  |  |  |  | ✓ | ✓ | ✓ |
`VK_FORMAT_R8G8B8A8_USCALED` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R8G8B8A8_SSCALED` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R8G8B8A8_UINT` | ✓ | ✓ |  | ✓ |  | ✓ | ✓ |  |  | ✓ | ✓ | ✓ |
`VK_FORMAT_R8G8B8A8_SINT` | ✓ | ✓ |  | ✓ |  | ✓ | ✓ |  |  | ✓ | ✓ | ✓ |
`VK_FORMAT_R8G8B8A8_SRGB` | ✓ | ✓ | ✓ |  |  | ✓ | ✓ | ✓ |  |  |  |  |
`VK_FORMAT_B8G8R8A8_UNORM` | ✓ | ✓ | ✓ |  |  | ✓ | ✓ | ✓ |  | ✓ | ✓ |  |
`VK_FORMAT_B8G8R8A8_SNORM` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_B8G8R8A8_USCALED` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_B8G8R8A8_SSCALED` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_B8G8R8A8_UINT` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_B8G8R8A8_SINT` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_B8G8R8A8_SRGB` | ✓ | ✓ | ✓ |  |  | ✓ | ✓ | ✓ |  |  |  |  |
`VK_FORMAT_A8B8G8R8_UNORM_PACK32` | ✓ | ✓ | ✓ |  |  | ✓ | ✓ | ✓ |  | ✓ | ✓ | ✓ |
`VK_FORMAT_A8B8G8R8_SNORM_PACK32` | ✓ | ✓ | ✓ |  |  |  |  |  |  | ✓ | ✓ | ✓ |
`VK_FORMAT_A8B8G8R8_USCALED_PACK32` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_A8B8G8R8_SSCALED_PACK32` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_A8B8G8R8_UINT_PACK32` | ✓ | ✓ |  |  |  | ✓ | ✓ |  |  | ✓ | ✓ | ✓ |
`VK_FORMAT_A8B8G8R8_SINT_PACK32` | ✓ | ✓ |  |  |  | ✓ | ✓ |  |  | ✓ | ✓ | ✓ |
`VK_FORMAT_A8B8G8R8_SRGB_PACK32` | ✓ | ✓ | ✓ |  |  | ✓ | ✓ | ✓ |  |  |  |  |

Table 61. Mandatory format support: 10- and 12-bit channels
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_ATOMIC_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_UNIFORM_TEXEL_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_VERTEX_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT` | ↓
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BLEND_BIT` | ↓
`VK_FORMAT_FEATURE_BLIT_DST_BIT` | ↓
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT` | ↓
`VK_FORMAT_FEATURE_BLIT_SRC_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT` | ↓
Format
`VK_FORMAT_A2R10G10B10_UNORM_PACK32` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_A2R10G10B10_SNORM_PACK32` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_A2R10G10B10_USCALED_PACK32` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_A2R10G10B10_SSCALED_PACK32` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_A2R10G10B10_UINT_PACK32` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_A2R10G10B10_SINT_PACK32` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_A2B10G10R10_UNORM_PACK32` | ✓ | ✓ | ✓ | ‡ |  | ✓ | ✓ | ✓ |  | ✓ | ✓ |  |
`VK_FORMAT_A2B10G10R10_SNORM_PACK32` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_A2B10G10R10_USCALED_PACK32` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_A2B10G10R10_SSCALED_PACK32` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_A2B10G10R10_UINT_PACK32` | ✓ | ✓ |  | ‡ |  | ✓ | ✓ |  |  |  | ✓ |  |
`VK_FORMAT_A2B10G10R10_SINT_PACK32` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R10X6_UNORM_PACK16` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R10X6G10X6_UNORM_2PACK16` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R12X4_UNORM_PACK16` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R12X4G12X4_UNORM_2PACK16` |  |  |  |  |  |  |  |  |  |  |  |  |
Format features marked with ‡ must be supported for `optimalTilingFeatures` if the `VkPhysicalDevice` supports the `shaderStorageImageExtendedFormats` feature.

Table 62. Mandatory format support: 16-bit channels
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_ATOMIC_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_UNIFORM_TEXEL_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_VERTEX_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT` | ↓
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BLEND_BIT` | ↓
`VK_FORMAT_FEATURE_BLIT_DST_BIT` | ↓
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT` | ↓
`VK_FORMAT_FEATURE_BLIT_SRC_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT` | ↓
Format
`VK_FORMAT_R16_UNORM` |  |  |  | ‡ |  |  |  |  |  | ✓ |  |  |
`VK_FORMAT_R16_SNORM` |  |  |  | ‡ |  |  |  |  |  | ✓ |  |  |
`VK_FORMAT_R16_USCALED` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R16_SSCALED` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R16_UINT` | ✓ | ✓ |  | ‡ |  | ✓ | ✓ |  |  | ✓ | ✓ |  |
`VK_FORMAT_R16_SINT` | ✓ | ✓ |  | ‡ |  | ✓ | ✓ |  |  | ✓ | ✓ |  |
`VK_FORMAT_R16_SFLOAT` | ✓ | ✓ | ✓ | ‡ |  | ✓ | ✓ | ✓ |  | ✓ | ✓ |  |
`VK_FORMAT_R16G16_UNORM` |  |  |  | ‡ |  |  |  |  |  | ✓ |  |  |
`VK_FORMAT_R16G16_SNORM` |  |  |  | ‡ |  |  |  |  |  | ✓ |  |  |
`VK_FORMAT_R16G16_USCALED` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R16G16_SSCALED` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R16G16_UINT` | ✓ | ✓ |  | ‡ |  | ✓ | ✓ |  |  | ✓ | ✓ |  |
`VK_FORMAT_R16G16_SINT` | ✓ | ✓ |  | ‡ |  | ✓ | ✓ |  |  | ✓ | ✓ |  |
`VK_FORMAT_R16G16_SFLOAT` | ✓ | ✓ | ✓ | ‡ |  | ✓ | ✓ | ✓ |  | ✓ | ✓ |  |
`VK_FORMAT_R16G16B16_UNORM` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R16G16B16_SNORM` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R16G16B16_USCALED` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R16G16B16_SSCALED` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R16G16B16_UINT` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R16G16B16_SINT` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R16G16B16_SFLOAT` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R16G16B16A16_UNORM` |  |  |  | ‡ |  |  |  |  |  | ✓ |  |  |
`VK_FORMAT_R16G16B16A16_SNORM` |  |  |  | ‡ |  |  |  |  |  | ✓ |  |  |
`VK_FORMAT_R16G16B16A16_USCALED` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R16G16B16A16_SSCALED` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R16G16B16A16_UINT` | ✓ | ✓ |  | ✓ |  | ✓ | ✓ |  |  | ✓ | ✓ | ✓ |
`VK_FORMAT_R16G16B16A16_SINT` | ✓ | ✓ |  | ✓ |  | ✓ | ✓ |  |  | ✓ | ✓ | ✓ |
`VK_FORMAT_R16G16B16A16_SFLOAT` | ✓ | ✓ | ✓ | ✓ |  | ✓ | ✓ | ✓ |  | ✓ | ✓ | ✓ |
Format features marked with ‡ must be supported for `optimalTilingFeatures` if the `VkPhysicalDevice` supports the `shaderStorageImageExtendedFormats` feature.

Table 63. Mandatory format support: 32-bit channels
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_ATOMIC_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_UNIFORM_TEXEL_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_VERTEX_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT` | ↓
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BLEND_BIT` | ↓
`VK_FORMAT_FEATURE_BLIT_DST_BIT` | ↓
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT` | ↓
`VK_FORMAT_FEATURE_BLIT_SRC_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT` | ↓
Format
`VK_FORMAT_R32_UINT` | ✓ | ✓ |  | ✓ | ✓ | ✓ | ✓ |  |  | ✓ | ✓ | ✓ | ✓
`VK_FORMAT_R32_SINT` | ✓ | ✓ |  | ✓ | ✓ | ✓ | ✓ |  |  | ✓ | ✓ | ✓ | ✓
`VK_FORMAT_R32_SFLOAT` | ✓ | ✓ |  | ✓ |  | ✓ | ✓ |  |  | ✓ | ✓ | ✓ |
`VK_FORMAT_R32G32_UINT` | ✓ | ✓ |  | ✓ |  | ✓ | ✓ |  |  | ✓ | ✓ | ✓ |
`VK_FORMAT_R32G32_SINT` | ✓ | ✓ |  | ✓ |  | ✓ | ✓ |  |  | ✓ | ✓ | ✓ |
`VK_FORMAT_R32G32_SFLOAT` | ✓ | ✓ |  | ✓ |  | ✓ | ✓ |  |  | ✓ | ✓ | ✓ |
`VK_FORMAT_R32G32B32_UINT` |  |  |  |  |  |  |  |  |  | ✓ |  |  |
`VK_FORMAT_R32G32B32_SINT` |  |  |  |  |  |  |  |  |  | ✓ |  |  |
`VK_FORMAT_R32G32B32_SFLOAT` |  |  |  |  |  |  |  |  |  | ✓ |  |  |
`VK_FORMAT_R32G32B32A32_UINT` | ✓ | ✓ |  | ✓ |  | ✓ | ✓ |  |  | ✓ | ✓ | ✓ |
`VK_FORMAT_R32G32B32A32_SINT` | ✓ | ✓ |  | ✓ |  | ✓ | ✓ |  |  | ✓ | ✓ | ✓ |
`VK_FORMAT_R32G32B32A32_SFLOAT` | ✓ | ✓ |  | ✓ |  | ✓ | ✓ |  |  | ✓ | ✓ | ✓ |

Table 64. Mandatory format support: 64-bit/uneven channels
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_ATOMIC_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_UNIFORM_TEXEL_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_VERTEX_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT` | ↓
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BLEND_BIT` | ↓
`VK_FORMAT_FEATURE_BLIT_DST_BIT` | ↓
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT` | ↓
`VK_FORMAT_FEATURE_BLIT_SRC_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT` | ↓
Format
`VK_FORMAT_R64_UINT` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R64_SINT` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R64_SFLOAT` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R64G64_UINT` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R64G64_SINT` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R64G64_SFLOAT` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R64G64B64_UINT` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R64G64B64_SINT` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R64G64B64_SFLOAT` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R64G64B64A64_UINT` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R64G64B64A64_SINT` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R64G64B64A64_SFLOAT` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_B10G11R11_UFLOAT_PACK32` | ✓ | ✓ | ✓ | ‡ |  |  |  |  |  |  | ✓ |  |
`VK_FORMAT_E5B9G9R9_UFLOAT_PACK32` | ✓ | ✓ | ✓ |  |  |  |  |  |  |  |  |  |
Format features marked with ‡ must be supported for `optimalTilingFeatures` if the `VkPhysicalDevice` supports the `shaderStorageImageExtendedFormats` feature.

Table 65. Mandatory format support: depth/stencil with `VkImageType` `VK_IMAGE_TYPE_2D`
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_ATOMIC_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_UNIFORM_TEXEL_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_VERTEX_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT` | ↓
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BLEND_BIT` | ↓
`VK_FORMAT_FEATURE_BLIT_DST_BIT` | ↓
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT` | ↓
`VK_FORMAT_FEATURE_BLIT_SRC_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT` | ↓
Format
`VK_FORMAT_D16_UNORM` | ✓ | ✓ |  |  |  |  |  |  | ✓ |  |  |  |
`VK_FORMAT_X8_D24_UNORM_PACK32` |  |  |  |  |  |  |  |  | † |  |  |  |
`VK_FORMAT_D32_SFLOAT` | ✓ | ✓ |  |  |  |  |  |  | † |  |  |  |
`VK_FORMAT_S8_UINT` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_D16_UNORM_S8_UINT` |  |  |  |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_D24_UNORM_S8_UINT` |  |  |  |  |  |  |  |  | † |  |  |  |
`VK_FORMAT_D32_SFLOAT_S8_UINT` |  |  |  |  |  |  |  |  | † |  |  |  |
`VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT` feature must be supported for at least one of `VK_FORMAT_X8_D24_UNORM_PACK32` and `VK_FORMAT_D32_SFLOAT`, and must be supported for at least one of `VK_FORMAT_D24_UNORM_S8_UINT` and `VK_FORMAT_D32_SFLOAT_S8_UINT`.

Table 66. Mandatory format support: BC compressed formats with `VkImageType` `VK_IMAGE_TYPE_2D` and `VK_IMAGE_TYPE_3D`
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_ATOMIC_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_UNIFORM_TEXEL_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_VERTEX_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT` | ↓
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BLEND_BIT` | ↓
`VK_FORMAT_FEATURE_BLIT_DST_BIT` | ↓
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT` | ↓
`VK_FORMAT_FEATURE_BLIT_SRC_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT` | ↓
Format
`VK_FORMAT_BC1_RGB_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_BC1_RGB_SRGB_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_BC1_RGBA_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_BC1_RGBA_SRGB_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_BC2_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_BC2_SRGB_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_BC3_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_BC3_SRGB_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_BC4_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_BC4_SNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_BC5_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_BC5_SNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_BC6H_UFLOAT_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_BC6H_SFLOAT_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_BC7_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_BC7_SRGB_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
The `VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT`, `VK_FORMAT_FEATURE_BLIT_SRC_BIT` and `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT` features must be supported in `optimalTilingFeatures` for all the formats in at least one of: this table, Mandatory format support: ETC2 and EAC compressed formats with `VkImageType` `VK_IMAGE_TYPE_2D`, or Mandatory format support: ASTC LDR compressed formats with `VkImageType` `VK_IMAGE_TYPE_2D`.

Table 67. Mandatory format support: ETC2 and EAC compressed formats with `VkImageType` `VK_IMAGE_TYPE_2D`
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_ATOMIC_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_UNIFORM_TEXEL_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_VERTEX_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT` | ↓
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BLEND_BIT` | ↓
`VK_FORMAT_FEATURE_BLIT_DST_BIT` | ↓
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT` | ↓
`VK_FORMAT_FEATURE_BLIT_SRC_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT` | ↓
Format
`VK_FORMAT_ETC2_R8G8B8_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ETC2_R8G8B8_SRGB_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ETC2_R8G8B8A1_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ETC2_R8G8B8A1_SRGB_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ETC2_R8G8B8A8_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ETC2_R8G8B8A8_SRGB_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_EAC_R11_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_EAC_R11_SNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_EAC_R11G11_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_EAC_R11G11_SNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
The `VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT`, `VK_FORMAT_FEATURE_BLIT_SRC_BIT` and `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT` features must be supported in `optimalTilingFeatures` for all the formats in at least one of: this table, Mandatory format support: BC compressed formats with `VkImageType` `VK_IMAGE_TYPE_2D` and `VK_IMAGE_TYPE_3D`, or Mandatory format support: ASTC LDR compressed formats with `VkImageType` `VK_IMAGE_TYPE_2D`.

Table 68. Mandatory format support: ASTC LDR compressed formats with `VkImageType` `VK_IMAGE_TYPE_2D`
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_ATOMIC_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_TEXEL_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_UNIFORM_TEXEL_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_VERTEX_BUFFER_BIT` | ↓
`VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT` | ↓
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BLEND_BIT` | ↓
`VK_FORMAT_FEATURE_BLIT_DST_BIT` | ↓
`VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT` | ↓
`VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT` | ↓
`VK_FORMAT_FEATURE_BLIT_SRC_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT` | ↓
Format
`VK_FORMAT_ASTC_4x4_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_4x4_SRGB_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_5x4_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_5x4_SRGB_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_5x5_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_5x5_SRGB_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_6x5_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_6x5_SRGB_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_6x6_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_6x6_SRGB_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_8x5_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_8x5_SRGB_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_8x6_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_8x6_SRGB_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_8x8_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_8x8_SRGB_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_10x5_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_10x5_SRGB_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_10x6_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_10x6_SRGB_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_10x8_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_10x8_SRGB_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_10x10_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_10x10_SRGB_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_12x10_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_12x10_SRGB_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_12x12_UNORM_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_ASTC_12x12_SRGB_BLOCK` | † | † | † |  |  |  |  |  |  |  |  |  |
The `VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT`, `VK_FORMAT_FEATURE_BLIT_SRC_BIT` and `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT` features must be supported in `optimalTilingFeatures` for all the formats in at least one of: this table, Mandatory format support: BC compressed formats with `VkImageType` `VK_IMAGE_TYPE_2D` and `VK_IMAGE_TYPE_3D`, or Mandatory format support: ETC2 and EAC compressed formats with `VkImageType` `VK_IMAGE_TYPE_2D`.

If cubic filtering is supported, `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_EXT` must be supported for the following image view types:

- `VK_IMAGE_VIEW_TYPE_2D`

- `VK_IMAGE_VIEW_TYPE_2D_ARRAY`

for the following formats:

- `VK_FORMAT_R4G4_UNORM_PACK8`

- `VK_FORMAT_R4G4B4A4_UNORM_PACK16`

- `VK_FORMAT_B4G4R4A4_UNORM_PACK16`

- `VK_FORMAT_R5G6B5_UNORM_PACK16`

- `VK_FORMAT_B5G6R5_UNORM_PACK16`

- `VK_FORMAT_R5G5B5A1_UNORM_PACK16`

- `VK_FORMAT_B5G5R5A1_UNORM_PACK16`

- `VK_FORMAT_A1R5G5B5_UNORM_PACK16`

- `VK_FORMAT_R8_UNORM`

- `VK_FORMAT_R8_SNORM`

- `VK_FORMAT_R8_SRGB`

- `VK_FORMAT_R8G8_UNORM`

- `VK_FORMAT_R8G8_SNORM`

- `VK_FORMAT_R8G8_SRGB`

- `VK_FORMAT_R8G8B8_UNORM`

- `VK_FORMAT_R8G8B8_SNORM`

- `VK_FORMAT_R8G8B8_SRGB`

- `VK_FORMAT_B8G8R8_UNORM`

- `VK_FORMAT_B8G8R8_SNORM`

- `VK_FORMAT_B8G8R8_SRGB`

- `VK_FORMAT_R8G8B8A8_UNORM`

- `VK_FORMAT_R8G8B8A8_SNORM`

- `VK_FORMAT_R8G8B8A8_SRGB`

- `VK_FORMAT_B8G8R8A8_UNORM`

- `VK_FORMAT_B8G8R8A8_SNORM`

- `VK_FORMAT_B8G8R8A8_SRGB`

- `VK_FORMAT_A8B8G8R8_UNORM_PACK32`

- `VK_FORMAT_A8B8G8R8_SNORM_PACK32`

- `VK_FORMAT_A8B8G8R8_SRGB_PACK32`

If ETC compressed formats are supported, `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_EXT` must be supported for the following image view types:

- `VK_IMAGE_VIEW_TYPE_2D`

- `VK_IMAGE_VIEW_TYPE_2D_ARRAY`

for the following additional formats:

- `VK_FORMAT_ETC2_R8G8B8_UNORM_BLOCK`

- `VK_FORMAT_ETC2_R8G8B8_SRGB_BLOCK`

- `VK_FORMAT_ETC2_R8G8B8A1_UNORM_BLOCK`

- `VK_FORMAT_ETC2_R8G8B8A1_SRGB_BLOCK`

- `VK_FORMAT_ETC2_R8G8B8A8_UNORM_BLOCK`

- `VK_FORMAT_ETC2_R8G8B8A8_SRGB_BLOCK`

If cubic filtering is supported for any other formats, the following image view types must be supported for those formats:

- `VK_IMAGE_VIEW_TYPE_2D`

- `VK_IMAGE_VIEW_TYPE_2D_ARRAY`

To be used with `VkImageView` with `subresourceRange.aspectMask` = `VK_IMAGE_ASPECT_COLOR_BIT`, sampler Y′CBCR conversion must be enabled for the following formats:

Table 69. Formats requiring sampler Y′CBCR conversion for `VK_IMAGE_ASPECT_COLOR_BIT` image views
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_FORCEABLE_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_SEPARATE_RECONSTRUCTION_FILTER_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_LINEAR_FILTER_BIT` | ↓
`VK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BIT` | ↓
`VK_FORMAT_FEATURE_COSITED_CHROMA_SAMPLES_BIT` | ↓
`VK_FORMAT_FEATURE_TRANSFER_DST_BIT` | ↓
`VK_FORMAT_FEATURE_TRANSFER_SRC_BIT` | ↓
`VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT` | ↓
`VK_FORMAT_FEATURE_DISJOINT_BIT` | ↓
Format | Planes
`VK_FORMAT_G8B8G8R8_422_UNORM` | 1 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_B8G8R8G8_422_UNORM` | 1 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_G8_B8_R8_3PLANE_420_UNORM` | 3 |  | ✓ | ✓ | ✓ | ✓ |  |  |  |  |
`VK_FORMAT_G8_B8R8_2PLANE_420_UNORM` | 2 |  | ✓ | ✓ | ✓ | ✓ |  |  |  |  |
`VK_FORMAT_G8_B8_R8_3PLANE_422_UNORM` | 3 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_G8_B8R8_2PLANE_422_UNORM` | 2 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_G8_B8_R8_3PLANE_444_UNORM` | 3 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R10X6G10X6B10X6A10X6_UNORM_4PACK16` | 1 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_G10X6B10X6G10X6R10X6_422_UNORM_4PACK16` | 1 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_B10X6G10X6R10X6G10X6_422_UNORM_4PACK16` | 1 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_420_UNORM_3PACK16` | 3 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_G10X6_B10X6R10X6_2PLANE_420_UNORM_3PACK16` | 2 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_422_UNORM_3PACK16` | 3 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_G10X6_B10X6R10X6_2PLANE_422_UNORM_3PACK16` | 2 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_444_UNORM_3PACK16` | 3 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_R12X4G12X4B12X4A12X4_UNORM_4PACK16` | 1 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_G12X4B12X4G12X4R12X4_422_UNORM_4PACK16` | 1 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_B12X4G12X4R12X4G12X4_422_UNORM_4PACK16` | 1 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_420_UNORM_3PACK16` | 3 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_G12X4_B12X4R12X4_2PLANE_420_UNORM_3PACK16` | 2 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_422_UNORM_3PACK16` | 3 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_G12X4_B12X4R12X4_2PLANE_422_UNORM_3PACK16` | 2 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_444_UNORM_3PACK16` | 3 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_G16B16G16R16_422_UNORM` | 1 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_B16G16R16G16_422_UNORM` | 1 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_G16_B16_R16_3PLANE_420_UNORM` | 3 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_G16_B16R16_2PLANE_420_UNORM` | 2 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_G16_B16_R16_3PLANE_422_UNORM` | 3 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_G16_B16R16_2PLANE_422_UNORM` | 2 |  |  |  |  |  |  |  |  |  |
`VK_FORMAT_G16_B16_R16_3PLANE_444_UNORM` | 3 |  |  |  |  |  |  |  |  |  |
Format features marked ✓ must be supported only if VkPhysicalDeviceSamplerYcbcrConversionFeatures is enabled, and only with VkImageType `VK_IMAGE_TYPE_2D`

Implementations are not required to support the `VK_IMAGE_CREATE_SPARSE_BINDING_BIT`, `VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT`, or `VK_IMAGE_CREATE_SPARSE_ALIASED_BIT` VkImageCreateFlags for the above formats that require sampler Y′CBCR conversion. To determine whether the implementation supports sparse image creation flags with these formats use vkGetPhysicalDeviceImageFormatProperties or vkGetPhysicalDeviceImageFormatProperties2.

`VK_FORMAT_FEATURE_FRAGMENT_DENSITY_MAP_BIT_EXT` must be supported for the following formats if the fragment density map feature is enabled:

- `VK_FORMAT_R8G8_UNORM`

`VK_FORMAT_FEATURE_ACCELERATION_STRUCTURE_VERTEX_BUFFER_BIT_KHR` must be supported for the following formats if the ray tracing feature is enabled:

- `VK_FORMAT_R32G32_SFLOAT`

- `VK_FORMAT_R32G32B32_SFLOAT`

- `VK_FORMAT_R16G16_SFLOAT`

- `VK_FORMAT_R16G16B16A16_SFLOAT`

- `VK_FORMAT_R16G16_SNORM`

- `VK_FORMAT_R16G16B16A16_SNORM`

## 40. Additional Capabilities

This chapter describes additional capabilities beyond the minimum capabilities described in the (Limits and Formats chapters, including:

- Additional Image Capabilities

- Additional Buffer Capabilities

- Optional Semaphore Capabilities

- Optional Fence Capabilities

- Timestamp Calibration Capabilities

### 40.1. Additional Image Capabilities

Additional image capabilities, such as larger dimensions or additional sample counts for certain image types, or additional capabilities for linear tiling format images, are described in this section.

To query additional capabilities specific to image types, call:

    VkResult vkGetPhysicalDeviceImageFormatProperties(
        VkPhysicalDevice                            physicalDevice,
        VkFormat                                    format,
        VkImageType                                 type,
        VkImageTiling                               tiling,
        VkImageUsageFlags                           usage,
        VkImageCreateFlags                          flags,
        VkImageFormatProperties*                    pImageFormatProperties);

- `physicalDevice` is the physical device from which to query the image capabilities.

- `format` is a VkFormat value specifying the image format, corresponding to VkImageCreateInfo::`format`.

- `type` is a VkImageType value specifying the image type, corresponding to VkImageCreateInfo::`imageType`.

- `tiling` is a VkImageTiling value specifying the image tiling, corresponding to VkImageCreateInfo::`tiling`.

- `usage` is a bitmask of VkImageUsageFlagBits specifying the intended usage of the image, corresponding to VkImageCreateInfo::`usage`.

- `flags` is a bitmask of VkImageCreateFlagBits specifying additional parameters of the image, corresponding to VkImageCreateInfo::`flags`.

- `pImageFormatProperties` is a pointer to a VkImageFormatProperties structure in which capabilities are returned.

The `format`, `type`, `tiling`, `usage`, and `flags` parameters correspond to parameters that would be consumed by vkCreateImage (as members of `VkImageCreateInfo`).

If `format` is not a supported image format, or if the combination of `format`, `type`, `tiling`, `usage`, and `flags` is not supported for images, then `vkGetPhysicalDeviceImageFormatProperties` returns `VK_ERROR_FORMAT_NOT_SUPPORTED`.

The limitations on an image format that are reported by `vkGetPhysicalDeviceImageFormatProperties` have the following property: if `usage1` and `usage2` of type VkImageUsageFlags are such that the bits set in `usage1` are a subset of the bits set in `usage2`, and `flags1` and `flags2` of type VkImageCreateFlags are such that the bits set in `flags1` are a subset of the bits set in `flags2`, then the limitations for `usage1` and `flags1` must be no more strict than the limitations for `usage2` and `flags2`, for all values of `format`, `type`, and `tiling`.

Valid Usage

- `tiling` must not be `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`. (Use vkGetPhysicalDeviceImageFormatProperties2 instead).

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `format` must be a valid VkFormat value

- `type` must be a valid VkImageType value

- `tiling` must be a valid VkImageTiling value

- `usage` must be a valid combination of VkImageUsageFlagBits values

- `usage` must not be `0`

- `flags` must be a valid combination of VkImageCreateFlagBits values

- `pImageFormatProperties` must be a valid pointer to a VkImageFormatProperties structure

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_FORMAT_NOT_SUPPORTED`

The `VkImageFormatProperties` structure is defined as:

    typedef struct VkImageFormatProperties {
        VkExtent3D            maxExtent;
        uint32_t              maxMipLevels;
        uint32_t              maxArrayLayers;
        VkSampleCountFlags    sampleCounts;
        VkDeviceSize          maxResourceSize;
    } VkImageFormatProperties;

- `maxExtent` are the maximum image dimensions. See the Allowed Extent Values section below for how these values are constrained by `type`.

- `maxMipLevels` is the maximum number of mipmap levels. `maxMipLevels` must be equal to the number of levels in the complete mipmap chain based on the `maxExtent.width`, `maxExtent.height`, and `maxExtent.depth`, except when one of the following conditions is true, in which case it may instead be `1`:

  - `vkGetPhysicalDeviceImageFormatProperties`::`tiling` was `VK_IMAGE_TILING_LINEAR`

  - VkPhysicalDeviceImageFormatInfo2::`tiling` was `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`

  - the VkPhysicalDeviceImageFormatInfo2::`pNext` chain included a VkPhysicalDeviceExternalImageFormatInfo structure with a handle type included in the `handleTypes` member for which mipmap image support is not required

  - image `format` is one of those listed in Formats requiring sampler Y′CBCR conversion for `VK_IMAGE_ASPECT_COLOR_BIT` image views

  - `flags` contains `VK_IMAGE_CREATE_SUBSAMPLED_BIT_EXT`

- `maxArrayLayers` is the maximum number of array layers. `maxArrayLayers` must be no less than VkPhysicalDeviceLimits::`maxImageArrayLayers`, except when one of the following conditions is true, in which case it may instead be `1`:

  - `tiling` is `VK_IMAGE_TILING_LINEAR`

  - `tiling` is `VK_IMAGE_TILING_OPTIMAL` and `type` is `VK_IMAGE_TYPE_3D`

  - `format` is one of those listed in Formats requiring sampler Y′CBCR conversion for `VK_IMAGE_ASPECT_COLOR_BIT` image views

- If `tiling` is `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`, then `maxArrayLayers` must not be 0.

- `sampleCounts` is a bitmask of VkSampleCountFlagBits specifying all the supported sample counts for this image as described below.

- `maxResourceSize` is an upper bound on the total image size in bytes, inclusive of all image subresources. Implementations may have an address space limit on total size of a resource, which is advertised by this property. `maxResourceSize` must be at least 231.

| Note There is no mechanism to query the size of an image before creating it, to compare that size against `maxResourceSize`. If an application attempts to create an image that exceeds this limit, the creation will fail and vkCreateImage will return `VK_ERROR_OUT_OF_DEVICE_MEMORY`. While the advertised limit must be at least 231, it may not be possible to create an image that approaches that size, particularly for `VK_IMAGE_TYPE_1D`.

If the combination of parameters to `vkGetPhysicalDeviceImageFormatProperties` is not supported by the implementation for use in vkCreateImage, then all members of `VkImageFormatProperties` will be filled with zero.

| Note Filling `VkImageFormatProperties` with zero for unsupported formats is an exception to the usual rule that output structures have undefined contents on error. This exception was unintentional, but is preserved for backwards compatibility.

To determine the image capabilities compatible with an external memory handle type, call:

    VkResult vkGetPhysicalDeviceExternalImageFormatPropertiesNV(
        VkPhysicalDevice                            physicalDevice,
        VkFormat                                    format,
        VkImageType                                 type,
        VkImageTiling                               tiling,
        VkImageUsageFlags                           usage,
        VkImageCreateFlags                          flags,
        VkExternalMemoryHandleTypeFlagsNV           externalHandleType,
        VkExternalImageFormatPropertiesNV*          pExternalImageFormatProperties);

- `physicalDevice` is the physical device from which to query the image capabilities

- `format` is the image format, corresponding to VkImageCreateInfo::`format`.

- `type` is the image type, corresponding to VkImageCreateInfo::`imageType`.

- `tiling` is the image tiling, corresponding to VkImageCreateInfo::`tiling`.

- `usage` is the intended usage of the image, corresponding to VkImageCreateInfo::`usage`.

- `flags` is a bitmask describing additional parameters of the image, corresponding to VkImageCreateInfo::`flags`.

- `externalHandleType` is either one of the bits from VkExternalMemoryHandleTypeFlagBitsNV, or 0.

- `pExternalImageFormatProperties` is a pointer to a VkExternalImageFormatPropertiesNV structure in which capabilities are returned.

If `externalHandleType` is 0, `pExternalImageFormatProperties->imageFormatProperties` will return the same values as a call to vkGetPhysicalDeviceImageFormatProperties, and the other members of `pExternalImageFormatProperties` will all be 0. Otherwise, they are filled in as described for VkExternalImageFormatPropertiesNV.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `format` must be a valid VkFormat value

- `type` must be a valid VkImageType value

- `tiling` must be a valid VkImageTiling value

- `usage` must be a valid combination of VkImageUsageFlagBits values

- `usage` must not be `0`

- `flags` must be a valid combination of VkImageCreateFlagBits values

- `externalHandleType` must be a valid combination of VkExternalMemoryHandleTypeFlagBitsNV values

- `pExternalImageFormatProperties` must be a valid pointer to a VkExternalImageFormatPropertiesNV structure

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_FORMAT_NOT_SUPPORTED`

The `VkExternalImageFormatPropertiesNV` structure is defined as:

    typedef struct VkExternalImageFormatPropertiesNV {
        VkImageFormatProperties              imageFormatProperties;
        VkExternalMemoryFeatureFlagsNV       externalMemoryFeatures;
        VkExternalMemoryHandleTypeFlagsNV    exportFromImportedHandleTypes;
        VkExternalMemoryHandleTypeFlagsNV    compatibleHandleTypes;
    } VkExternalImageFormatPropertiesNV;

- `imageFormatProperties` will be filled in as when calling vkGetPhysicalDeviceImageFormatProperties, but the values returned may vary depending on the external handle type requested.

- `externalMemoryFeatures` is a bitmask of VkExternalMemoryFeatureFlagBitsNV, indicating properties of the external memory handle type (vkGetPhysicalDeviceExternalImageFormatPropertiesNV::`externalHandleType`) being queried, or 0 if the external memory handle type is 0.

- `exportFromImportedHandleTypes` is a bitmask of VkExternalMemoryHandleTypeFlagBitsNV containing a bit set for every external handle type that may be used to create memory from which the handles of the type specified in vkGetPhysicalDeviceExternalImageFormatPropertiesNV::`externalHandleType` can be exported, or 0 if the external memory handle type is 0.

- `compatibleHandleTypes` is a bitmask of VkExternalMemoryHandleTypeFlagBitsNV containing a bit set for every external handle type that may be specified simultaneously with the handle type specified by vkGetPhysicalDeviceExternalImageFormatPropertiesNV::`externalHandleType` when calling vkAllocateMemory, or 0 if the external memory handle type is 0. `compatibleHandleTypes` will always contain vkGetPhysicalDeviceExternalImageFormatPropertiesNV::`externalHandleType`

Bits which can be set in VkExternalImageFormatPropertiesNV::`externalMemoryFeatures`, indicating properties of the external memory handle type, are:

    typedef enum VkExternalMemoryFeatureFlagBitsNV {
        VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT_NV = 0x00000001,
        VK_EXTERNAL_MEMORY_FEATURE_EXPORTABLE_BIT_NV = 0x00000002,
        VK_EXTERNAL_MEMORY_FEATURE_IMPORTABLE_BIT_NV = 0x00000004,
        VK_EXTERNAL_MEMORY_FEATURE_FLAG_BITS_MAX_ENUM_NV = 0x7FFFFFFF
    } VkExternalMemoryFeatureFlagBitsNV;

- `VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT_NV` specifies that external memory of the specified type must be created as a dedicated allocation when used in the manner specified.

- `VK_EXTERNAL_MEMORY_FEATURE_EXPORTABLE_BIT_NV` specifies that the implementation supports exporting handles of the specified type.

- `VK_EXTERNAL_MEMORY_FEATURE_IMPORTABLE_BIT_NV` specifies that the implementation supports importing handles of the specified type.

    typedef VkFlags VkExternalMemoryFeatureFlagsNV;

`VkExternalMemoryFeatureFlagsNV` is a bitmask type for setting a mask of zero or more VkExternalMemoryFeatureFlagBitsNV.

To query additional capabilities specific to image types, call:

    VkResult vkGetPhysicalDeviceImageFormatProperties2(
        VkPhysicalDevice                            physicalDevice,
        const VkPhysicalDeviceImageFormatInfo2*     pImageFormatInfo,
        VkImageFormatProperties2*                   pImageFormatProperties);

or the equivalent command

    VkResult vkGetPhysicalDeviceImageFormatProperties2KHR(
        VkPhysicalDevice                            physicalDevice,
        const VkPhysicalDeviceImageFormatInfo2*     pImageFormatInfo,
        VkImageFormatProperties2*                   pImageFormatProperties);

- `physicalDevice` is the physical device from which to query the image capabilities.

- `pImageFormatInfo` is a pointer to a VkPhysicalDeviceImageFormatInfo2 structure describing the parameters that would be consumed by vkCreateImage.

- `pImageFormatProperties` is a pointer to a VkImageFormatProperties2 structure in which capabilities are returned.

`vkGetPhysicalDeviceImageFormatProperties2` behaves similarly to vkGetPhysicalDeviceImageFormatProperties, with the ability to return extended information in a `pNext` chain of output structures.

Valid Usage

- If the `pNext` chain of `pImageFormatProperties` includes a VkAndroidHardwareBufferUsageANDROID structure, the `pNext` chain of `pImageFormatInfo` must include a VkPhysicalDeviceExternalImageFormatInfo structure with `handleType` set to `VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID`.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pImageFormatInfo` must be a valid pointer to a valid VkPhysicalDeviceImageFormatInfo2 structure

- `pImageFormatProperties` must be a valid pointer to a VkImageFormatProperties2 structure

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

  - `VK_ERROR_FORMAT_NOT_SUPPORTED`

The `VkPhysicalDeviceImageFormatInfo2` structure is defined as:

    typedef struct VkPhysicalDeviceImageFormatInfo2 {
        VkStructureType       sType;
        const void*           pNext;
        VkFormat              format;
        VkImageType           type;
        VkImageTiling         tiling;
        VkImageUsageFlags     usage;
        VkImageCreateFlags    flags;
    } VkPhysicalDeviceImageFormatInfo2;

or the equivalent

    typedef VkPhysicalDeviceImageFormatInfo2 VkPhysicalDeviceImageFormatInfo2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure. The `pNext` chain of `VkPhysicalDeviceImageFormatInfo2` is used to provide additional image parameters to `vkGetPhysicalDeviceImageFormatProperties2`.

- `format` is a VkFormat value indicating the image format, corresponding to VkImageCreateInfo::`format`.

- `type` is a VkImageType value indicating the image type, corresponding to VkImageCreateInfo::`imageType`.

- `tiling` is a VkImageTiling value indicating the image tiling, corresponding to VkImageCreateInfo::`tiling`.

- `usage` is a bitmask of VkImageUsageFlagBits indicating the intended usage of the image, corresponding to VkImageCreateInfo::`usage`.

- `flags` is a bitmask of VkImageCreateFlagBits indicating additional parameters of the image, corresponding to VkImageCreateInfo::`flags`.

The members of `VkPhysicalDeviceImageFormatInfo2` correspond to the arguments to vkGetPhysicalDeviceImageFormatProperties, with `sType` and `pNext` added for extensibility.

Valid Usage

- `tiling` must be `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT` if and only if the `pNext` chain includes VkPhysicalDeviceImageDrmFormatModifierInfoEXT.

- If `tiling` is `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT` and `flags` contains `VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT`, then the `pNext` chain must include a VkImageFormatListCreateInfo structure with non-zero `viewFormatCount`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGE_FORMAT_INFO_2`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkImageFormatListCreateInfo, VkImageStencilUsageCreateInfo, VkPhysicalDeviceExternalImageFormatInfo, VkPhysicalDeviceImageDrmFormatModifierInfoEXT, or VkPhysicalDeviceImageViewImageFormatInfoEXT

- The `sType` value of each struct in the `pNext` chain must be unique

- `format` must be a valid VkFormat value

- `type` must be a valid VkImageType value

- `tiling` must be a valid VkImageTiling value

- `usage` must be a valid combination of VkImageUsageFlagBits values

- `usage` must not be `0`

- `flags` must be a valid combination of VkImageCreateFlagBits values

The `VkImageFormatProperties2` structure is defined as:

    typedef struct VkImageFormatProperties2 {
        VkStructureType            sType;
        void*                      pNext;
        VkImageFormatProperties    imageFormatProperties;
    } VkImageFormatProperties2;

or the equivalent

    typedef VkImageFormatProperties2 VkImageFormatProperties2KHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure. The `pNext` chain of `VkImageFormatProperties2` is used to allow the specification of additional capabilities to be returned from `vkGetPhysicalDeviceImageFormatProperties2`.

- `imageFormatProperties` is a VkImageFormatProperties structure in which capabilities are returned.

If the combination of parameters to `vkGetPhysicalDeviceImageFormatProperties2` is not supported by the implementation for use in vkCreateImage, then all members of `imageFormatProperties` will be filled with zero.

| Note Filling `imageFormatProperties` with zero for unsupported formats is an exception to the usual rule that output structures have undefined contents on error. This exception was unintentional, but is preserved for backwards compatibility. This exeption only applies to `imageFormatProperties`, not `sType`, `pNext`, or any structures chained from `pNext`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_IMAGE_FORMAT_PROPERTIES_2`

- Each `pNext` member of any structure (including this one) in the `pNext` chain must be either `NULL` or a pointer to a valid instance of VkAndroidHardwareBufferUsageANDROID, VkExternalImageFormatProperties, VkFilterCubicImageViewImageFormatPropertiesEXT, VkSamplerYcbcrConversionImageFormatProperties, or VkTextureLODGatherFormatPropertiesAMD

- The `sType` value of each struct in the `pNext` chain must be unique

To determine if texture gather functions that take explicit LOD and/or bias argument values can be used with a given image format, add a VkImageFormatProperties2 structure to the `pNext` chain of the VkPhysicalDeviceImageFormatInfo2 structure and a VkTextureLODGatherFormatPropertiesAMD structure to the `pNext` chain of the VkImageFormatProperties2 structure.

The `VkTextureLODGatherFormatPropertiesAMD` structure is defined as:

    typedef struct VkTextureLODGatherFormatPropertiesAMD {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           supportsTextureGatherLODBiasAMD;
    } VkTextureLODGatherFormatPropertiesAMD;

- `sType` is the type of this structure.

- `pNext` is `NULL`.

- `supportsTextureGatherLODBiasAMD` tells if the image format can be used with texture gather bias/LOD functions, as introduced by the `VK_AMD_texture_gather_bias_lod` extension. This field is set by the implementation. User-specified value is ignored.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_TEXTURE_LOD_GATHER_FORMAT_PROPERTIES_AMD`

To determine the image capabilities compatible with an external memory handle type, add a VkPhysicalDeviceExternalImageFormatInfo structure to the `pNext` chain of the VkPhysicalDeviceImageFormatInfo2 structure and a `VkExternalImageFormatProperties` structure to the `pNext` chain of the VkImageFormatProperties2 structure.

The `VkPhysicalDeviceExternalImageFormatInfo` structure is defined as:

    typedef struct VkPhysicalDeviceExternalImageFormatInfo {
        VkStructureType                       sType;
        const void*                           pNext;
        VkExternalMemoryHandleTypeFlagBits    handleType;
    } VkPhysicalDeviceExternalImageFormatInfo;

or the equivalent

    typedef VkPhysicalDeviceExternalImageFormatInfo VkPhysicalDeviceExternalImageFormatInfoKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `handleType` is a VkExternalMemoryHandleTypeFlagBits value specifying the memory handle type that will be used with the memory associated with the image.

If `handleType` is 0, vkGetPhysicalDeviceImageFormatProperties2 will behave as if VkPhysicalDeviceExternalImageFormatInfo was not present, and VkExternalImageFormatProperties will be ignored.

If `handleType` is not compatible with the `format`, `type`, `tiling`, `usage`, and `flags` specified in VkPhysicalDeviceImageFormatInfo2, then vkGetPhysicalDeviceImageFormatProperties2 returns `VK_ERROR_FORMAT_NOT_SUPPORTED`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_IMAGE_FORMAT_INFO`

- If `handleType` is not `0`, `handleType` must be a valid VkExternalMemoryHandleTypeFlagBits value

Possible values of VkPhysicalDeviceExternalImageFormatInfo::`handleType`, specifying an external memory handle type, are:

    typedef enum VkExternalMemoryHandleTypeFlagBits {
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_FD_BIT = 0x00000001,
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT = 0x00000002,
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT = 0x00000004,
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_BIT = 0x00000008,
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_KMT_BIT = 0x00000010,
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_HEAP_BIT = 0x00000020,
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_RESOURCE_BIT = 0x00000040,
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_DMA_BUF_BIT_EXT = 0x00000200,
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID = 0x00000400,
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_ALLOCATION_BIT_EXT = 0x00000080,
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_MAPPED_FOREIGN_MEMORY_BIT_EXT = 0x00000100,
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_FD_BIT_KHR = VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_FD_BIT,
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT_KHR = VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT,
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT_KHR = VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT,
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_BIT_KHR = VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_BIT,
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_KMT_BIT_KHR = VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_KMT_BIT,
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_HEAP_BIT_KHR = VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_HEAP_BIT,
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_RESOURCE_BIT_KHR = VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_RESOURCE_BIT,
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkExternalMemoryHandleTypeFlagBits;

or the equivalent

    typedef VkExternalMemoryHandleTypeFlagBits VkExternalMemoryHandleTypeFlagBitsKHR;

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_FD_BIT` specifies a POSIX file descriptor handle that has only limited valid usage outside of Vulkan and other compatible APIs. It must be compatible with the POSIX system calls `dup`, `dup2`, `close`, and the non-standard system call `dup3`. Additionally, it must be transportable over a socket using an `SCM_RIGHTS` control message. It owns a reference to the underlying memory resource represented by its Vulkan memory object.

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT` specifies an NT handle that has only limited valid usage outside of Vulkan and other compatible APIs. It must be compatible with the functions `DuplicateHandle`, `CloseHandle`, `CompareObjectHandles`, `GetHandleInformation`, and `SetHandleInformation`. It owns a reference to the underlying memory resource represented by its Vulkan memory object.

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT` specifies a global share handle that has only limited valid usage outside of Vulkan and other compatible APIs. It is not compatible with any native APIs. It does not own a reference to the underlying memory resource represented its Vulkan memory object, and will therefore become invalid when all Vulkan memory objects associated with it are destroyed.

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_BIT` specifies an NT handle returned by `IDXGIResource1`::`CreateSharedHandle` referring to a Direct3D 10 or 11 texture resource. It owns a reference to the memory used by the Direct3D resource.

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_KMT_BIT` specifies a global share handle returned by `IDXGIResource`::`GetSharedHandle` referring to a Direct3D 10 or 11 texture resource. It does not own a reference to the underlying Direct3D resource, and will therefore become invalid when all Vulkan memory objects and Direct3D resources associated with it are destroyed.

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_HEAP_BIT` specifies an NT handle returned by `ID3D12Device`::`CreateSharedHandle` referring to a Direct3D 12 heap resource. It owns a reference to the resources used by the Direct3D heap.

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_RESOURCE_BIT` specifies an NT handle returned by `ID3D12Device`::`CreateSharedHandle` referring to a Direct3D 12 committed resource. It owns a reference to the memory used by the Direct3D resource.

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_ALLOCATION_BIT_EXT` specifies a host pointer returned by a host memory allocation command. It does not own a reference to the underlying memory resource, and will therefore become invalid if the host memory is freed.

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_MAPPED_FOREIGN_MEMORY_BIT_EXT` specifies a host pointer to host mapped foreign memory. It does not own a reference to the underlying memory resource, and will therefore become invalid if the foreign memory is unmapped or otherwise becomes no longer available.

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_DMA_BUF_BIT_EXT` is a file descriptor for a Linux dma_buf. It owns a reference to the underlying memory resource represented by its Vulkan memory object.

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID` specifies an AHardwareBuffer object defined by the Android NDK. See Android Hardware Buffers for more details of this handle type.

Some external memory handle types can only be shared within the same underlying physical device and/or the same driver version, as defined in the following table:

Table 70. External memory handle types compatibility
Handle type | `VkPhysicalDeviceIDProperties`::`driverUUID` | `VkPhysicalDeviceIDProperties`::`deviceUUID`
`VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_FD_BIT` | Must match | Must match
`VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT` | Must match | Must match
`VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT` | Must match | Must match
`VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_BIT` | Must match | Must match
`VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_KMT_BIT` | Must match | Must match
`VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_HEAP_BIT` | Must match | Must match
`VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_RESOURCE_BIT` | Must match | Must match
`VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_ALLOCATION_BIT_EXT` | No restriction | No restriction
`VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_MAPPED_FOREIGN_MEMORY_BIT_EXT` | No restriction | No restriction
`VK_EXTERNAL_MEMORY_HANDLE_TYPE_DMA_BUF_BIT_EXT` | No restriction | No restriction
`VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID` | No restriction | No restriction

| Note The above table does not restrict the drivers and devices with which `VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_ALLOCATION_BIT_EXT` and `VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_MAPPED_FOREIGN_MEMORY_BIT_EXT` may be shared, as these handle types inherently mean memory that does not come from the same device, as they import memory from the host or a foreign device, respectively.

| Note Even though the above table does not restrict the drivers and devices with which `VK_EXTERNAL_MEMORY_HANDLE_TYPE_DMA_BUF_BIT_EXT` may be shared, query mechanisms exist in the Vulkan API that prevent the import of incompatible dma-bufs (such as vkGetMemoryFdPropertiesKHR) and that prevent incompatible usage of dma-bufs (such as VkPhysicalDeviceExternalBufferInfo and VkPhysicalDeviceExternalImageFormatInfo).

    typedef VkFlags VkExternalMemoryHandleTypeFlags;

or the equivalent

    typedef VkExternalMemoryHandleTypeFlags VkExternalMemoryHandleTypeFlagsKHR;

`VkExternalMemoryHandleTypeFlags` is a bitmask type for setting a mask of zero or more VkExternalMemoryHandleTypeFlagBits.

The `VkExternalImageFormatProperties` structure is defined as:

    typedef struct VkExternalImageFormatProperties {
        VkStructureType               sType;
        void*                         pNext;
        VkExternalMemoryProperties    externalMemoryProperties;
    } VkExternalImageFormatProperties;

or the equivalent

    typedef VkExternalImageFormatProperties VkExternalImageFormatPropertiesKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `externalMemoryProperties` is a VkExternalMemoryProperties structure specifying various capabilities of the external handle type when used with the specified image creation parameters.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_EXTERNAL_IMAGE_FORMAT_PROPERTIES`

The `VkExternalMemoryProperties` structure is defined as:

    typedef struct VkExternalMemoryProperties {
        VkExternalMemoryFeatureFlags       externalMemoryFeatures;
        VkExternalMemoryHandleTypeFlags    exportFromImportedHandleTypes;
        VkExternalMemoryHandleTypeFlags    compatibleHandleTypes;
    } VkExternalMemoryProperties;

or the equivalent

    typedef VkExternalMemoryProperties VkExternalMemoryPropertiesKHR;

- `externalMemoryFeatures` is a bitmask of VkExternalMemoryFeatureFlagBits specifying the features of `handleType`.

- `exportFromImportedHandleTypes` is a bitmask of VkExternalMemoryHandleTypeFlagBits specifying which types of imported handle `handleType` can be exported from.

- `compatibleHandleTypes` is a bitmask of VkExternalMemoryHandleTypeFlagBits specifying handle types which can be specified at the same time as `handleType` when creating an image compatible with external memory.

`compatibleHandleTypes` must include at least `handleType`. Inclusion of a handle type in `compatibleHandleTypes` does not imply the values returned in VkImageFormatProperties2 will be the same when VkPhysicalDeviceExternalImageFormatInfo::`handleType` is set to that type. The application is responsible for querying the capabilities of all handle types intended for concurrent use in a single image and intersecting them to obtain the compatible set of capabilities.

Bits which may be set in VkExternalMemoryProperties::`externalMemoryFeatures`, specifying features of an external memory handle type, are:

    typedef enum VkExternalMemoryFeatureFlagBits {
        VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT = 0x00000001,
        VK_EXTERNAL_MEMORY_FEATURE_EXPORTABLE_BIT = 0x00000002,
        VK_EXTERNAL_MEMORY_FEATURE_IMPORTABLE_BIT = 0x00000004,
        VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT_KHR = VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT,
        VK_EXTERNAL_MEMORY_FEATURE_EXPORTABLE_BIT_KHR = VK_EXTERNAL_MEMORY_FEATURE_EXPORTABLE_BIT,
        VK_EXTERNAL_MEMORY_FEATURE_IMPORTABLE_BIT_KHR = VK_EXTERNAL_MEMORY_FEATURE_IMPORTABLE_BIT,
        VK_EXTERNAL_MEMORY_FEATURE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkExternalMemoryFeatureFlagBits;

or the equivalent

    typedef VkExternalMemoryFeatureFlagBits VkExternalMemoryFeatureFlagBitsKHR;

- `VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT` specifies that images or buffers created with the specified parameters and handle type must use the mechanisms defined by VkMemoryDedicatedRequirements and VkMemoryDedicatedAllocateInfo to create (or import) a dedicated allocation for the image or buffer.

- `VK_EXTERNAL_MEMORY_FEATURE_EXPORTABLE_BIT` specifies that handles of this type can be exported from Vulkan memory objects.

- `VK_EXTERNAL_MEMORY_FEATURE_IMPORTABLE_BIT` specifies that handles of this type can be imported as Vulkan memory objects.

Because their semantics in external APIs roughly align with that of an image or buffer with a dedicated allocation in Vulkan, implementations are required to report `VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT` for the following external handle types:

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_BIT`

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_KMT_BIT`

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_RESOURCE_BIT`

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID` for images only

Implementations must not report `VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT` for buffers with external handle type `VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID`. Implementations must not report `VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT` for images or buffers with external handle type `VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_ALLOCATION_BIT_EXT`, or `VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_MAPPED_FOREIGN_MEMORY_BIT_EXT`.

    typedef VkFlags VkExternalMemoryFeatureFlags;

or the equivalent

    typedef VkExternalMemoryFeatureFlags VkExternalMemoryFeatureFlagsKHR;

`VkExternalMemoryFeatureFlags` is a bitmask type for setting a mask of zero or more VkExternalMemoryFeatureFlagBits.

To query the image capabilities that are compatible with a Linux DRM format modifier, set VkPhysicalDeviceImageFormatInfo2::`tiling` to `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT` and add a VkPhysicalDeviceImageDrmFormatModifierInfoEXT structure to the `pNext` chain of VkPhysicalDeviceImageFormatInfo2.

The VkPhysicalDeviceImageDrmFormatModifierInfoEXT structure is defined as:

    typedef struct VkPhysicalDeviceImageDrmFormatModifierInfoEXT {
        VkStructureType    sType;
        const void*        pNext;
        uint64_t           drmFormatModifier;
        VkSharingMode      sharingMode;
        uint32_t           queueFamilyIndexCount;
        const uint32_t*    pQueueFamilyIndices;
    } VkPhysicalDeviceImageDrmFormatModifierInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `drmFormatModifier` is the image’s Linux DRM format modifier, corresponding to VkImageDrmFormatModifierExplicitCreateInfoEXT::`modifier` or to VkImageDrmFormatModifierListCreateInfoEXT::`pModifiers`.

- `sharingMode` specifies how the image will be accessed by multiple queue families.

- `queueFamilyIndexCount` is the number of entries in the `pQueueFamilyIndices` array.

- `pQueueFamilyIndices` is a list of queue families that will access the image (ignored if `sharingMode` is not `VK_SHARING_MODE_CONCURRENT`).

If the `drmFormatModifier` is incompatible with the parameters specified in VkPhysicalDeviceImageFormatInfo2 and its `pNext` chain, then vkGetPhysicalDeviceImageFormatProperties2 returns `VK_ERROR_FORMAT_NOT_SUPPORTED`. The implementation must support the query of any `drmFormatModifier`, including unknown and invalid modifier values.

Valid Usage

- If `sharingMode` is `VK_SHARING_MODE_CONCURRENT`, then `pQueueFamilyIndices` must be a valid pointer to an array of `queueFamilyIndexCount` `uint32_t` values.

- If `sharingMode` is `VK_SHARING_MODE_CONCURRENT`, then `queueFamilyIndexCount` must be greater than `1`.

- If `sharingMode` is `VK_SHARING_MODE_CONCURRENT`, each element of `pQueueFamilyIndices` must be unique and must be less than the `pQueueFamilyPropertyCount` returned by vkGetPhysicalDeviceQueueFamilyProperties2 for the `physicalDevice` that was used to create `device`.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGE_DRM_FORMAT_MODIFIER_INFO_EXT`

- `sharingMode` must be a valid VkSharingMode value

To determine the number of combined image samplers required to support a multi-planar format, add VkSamplerYcbcrConversionImageFormatProperties to the `pNext` chain of the VkImageFormatProperties2 structure in a call to `vkGetPhysicalDeviceImageFormatProperties2`.

The `VkSamplerYcbcrConversionImageFormatProperties` structure is defined as:

    typedef struct VkSamplerYcbcrConversionImageFormatProperties {
        VkStructureType    sType;
        void*              pNext;
        uint32_t           combinedImageSamplerDescriptorCount;
    } VkSamplerYcbcrConversionImageFormatProperties;

or the equivalent

    typedef VkSamplerYcbcrConversionImageFormatProperties VkSamplerYcbcrConversionImageFormatPropertiesKHR;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `combinedImageSamplerDescriptorCount` is the number of combined image sampler descriptors that the implementation uses to access the format.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_IMAGE_FORMAT_PROPERTIES`

`combinedImageSamplerDescriptorCount` is a number between 1 and the number of planes in the format. A descriptor set layout binding with immutable Y′CBCR conversion samplers will have a maximum `combinedImageSamplerDescriptorCount` which is the maximum across all formats supported by its samplers of the `combinedImageSamplerDescriptorCount` for each format. Descriptor sets with that layout will internally use that maximum `combinedImageSamplerDescriptorCount` descriptors for each descriptor in the binding. This expanded number of descriptors will be consumed from the descriptor pool when a descriptor set is allocated, and counts towards the `maxDescriptorSetSamplers`, `maxDescriptorSetSampledImages`, `maxPerStageDescriptorSamplers`, and `maxPerStageDescriptorSampledImages` limits.

| Note All descriptors in a binding use the same maximum `combinedImageSamplerDescriptorCount` descriptors to allow implementations to use a uniform stride for dynamic indexing of the descriptors in the binding. For example, consider a descriptor set layout binding with two descriptors and immutable samplers for multi-planar formats that have `VkSamplerYcbcrConversionImageFormatProperties`::`combinedImageSamplerDescriptorCount` values of `2` and `3` respectively. There are two descriptors in the binding and the maximum `combinedImageSamplerDescriptorCount` is `3`, so descriptor sets with this layout consume `6` descriptors from the descriptor pool. To create a descriptor pool that allows allocating four descriptor sets with this layout, `descriptorCount` must be at least `24`.

To obtain optimal Android hardware buffer usage flags for specific image creation parameters, add a `VkAndroidHardwareBufferUsageANDROID` structure to the `pNext` chain of a VkImageFormatProperties2 structure passed to vkGetPhysicalDeviceImageFormatProperties2. This structure is defined as:

    typedef struct VkAndroidHardwareBufferUsageANDROID {
        VkStructureType    sType;
        void*              pNext;
        uint64_t           androidHardwareBufferUsage;
    } VkAndroidHardwareBufferUsageANDROID;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `androidHardwareBufferUsage` returns the Android hardware buffer usage flags.

The `androidHardwareBufferUsage` field must include Android hardware buffer usage flags listed in the AHardwareBuffer Usage Equivalence table when the corresponding Vulkan image usage or image creation flags are included in the `usage` or `flags` fields of VkPhysicalDeviceImageFormatInfo2. It must include at least one GPU usage flag (`AHARDWAREBUFFER_USAGE_GPU_`*), even if none of the corresponding Vulkan usages or flags are requested.

| Note Requiring at least one GPU usage flag ensures that Android hardware buffer memory will be allocated in a memory pool accessible to the Vulkan implementation, and that specializing the memory layout based on usage flags does not prevent it from being compatible with Vulkan. Implementations may avoid unnecessary restrictions caused by this requirement by using vendor usage flags to indicate that only the Vulkan uses indicated in VkImageFormatProperties2 are required.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_ANDROID_HARDWARE_BUFFER_USAGE_ANDROID`

To determine if cubic filtering can be used with a given image format and a given image view type add a VkPhysicalDeviceImageViewImageFormatInfoEXT structure to the `pNext` chain of the VkPhysicalDeviceImageFormatInfo2 structure, and a VkFilterCubicImageViewImageFormatPropertiesEXT structure to the `pNext` chain of the VkImageFormatProperties2 structure.

The `VkPhysicalDeviceImageViewImageFormatInfoEXT` structure is defined as:

    typedef struct VkPhysicalDeviceImageViewImageFormatInfoEXT {
        VkStructureType    sType;
        void*              pNext;
        VkImageViewType    imageViewType;
    } VkPhysicalDeviceImageViewImageFormatInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `imageViewType` is a VkImageViewType value specifying the type of the image view.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGE_VIEW_IMAGE_FORMAT_INFO_EXT`

- `imageViewType` must be a valid VkImageViewType value

The `VkFilterCubicImageViewImageFormatPropertiesEXT` structure is defined as:

    typedef struct VkFilterCubicImageViewImageFormatPropertiesEXT {
        VkStructureType    sType;
        void*              pNext;
        VkBool32           filterCubic;
        VkBool32           filterCubicMinmax;
    } VkFilterCubicImageViewImageFormatPropertiesEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `filterCubic` tells if image format, image type and image view type can be used with cubic filtering. This field is set by the implementation. User-specified value is ignored.

- `filterCubicMinmax` tells if image format, image type and image view type can be used with cubic filtering and minmax filtering. This field is set by the implementation. User-specified value is ignored.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_FILTER_CUBIC_IMAGE_VIEW_IMAGE_FORMAT_PROPERTIES_EXT`

Valid Usage

- If the `pNext` chain of the VkImageFormatProperties2 structure includes a VkFilterCubicImageViewImageFormatPropertiesEXT structure, the `pNext` chain of the VkPhysicalDeviceImageFormatInfo2 structure must include a VkPhysicalDeviceImageViewImageFormatInfoEXT structure with an `imageViewType` that is compatible with `imageType`.

#### 40.1.1. Supported Sample Counts

`vkGetPhysicalDeviceImageFormatProperties` returns a bitmask of VkSampleCountFlagBits in `sampleCounts` specifying the supported sample counts for the image parameters.

`sampleCounts` will be set to `VK_SAMPLE_COUNT_1_BIT` if at least one of the following conditions is true:

- `tiling` is `VK_IMAGE_TILING_LINEAR`

- `type` is not `VK_IMAGE_TYPE_2D`

- `flags` contains `VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT`

- Neither the `VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT` flag nor the `VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT` flag in `VkFormatProperties`::`optimalTilingFeatures` returned by vkGetPhysicalDeviceFormatProperties is set

- VkPhysicalDeviceExternalImageFormatInfo::`handleType` is an external handle type for which multisampled image support is not required.

- `format` is one of those listed in Formats requiring sampler Y′CBCR conversion for `VK_IMAGE_ASPECT_COLOR_BIT` image views

- `usage` contains `VK_IMAGE_USAGE_SHADING_RATE_IMAGE_BIT_NV`

- `usage` contains `VK_IMAGE_USAGE_FRAGMENT_DENSITY_MAP_BIT_EXT`

Otherwise, the bits set in `sampleCounts` will be the sample counts supported for the specified values of `usage` and `format`. For each bit set in `usage`, the supported sample counts relate to the limits in `VkPhysicalDeviceLimits` as follows:

- If `usage` includes `VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT` and `format` is a floating- or fixed-point color format, a superset of `VkPhysicalDeviceLimits`::`framebufferColorSampleCounts`

- If `usage` includes `VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT` and `format` is an integer format, a superset of `VkPhysicalDeviceVulkan12Properties`::`framebufferIntegerColorSampleCounts`

- If `usage` includes `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT`, and `format` includes a depth aspect, a superset of `VkPhysicalDeviceLimits`::`framebufferDepthSampleCounts`

- If `usage` includes `VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT`, and `format` includes a stencil aspect, a superset of `VkPhysicalDeviceLimits`::`framebufferStencilSampleCounts`

- If `usage` includes `VK_IMAGE_USAGE_SAMPLED_BIT`, and `format` includes a color aspect, a superset of `VkPhysicalDeviceLimits`::`sampledImageColorSampleCounts`

- If `usage` includes `VK_IMAGE_USAGE_SAMPLED_BIT`, and `format` includes a depth aspect, a superset of `VkPhysicalDeviceLimits`::`sampledImageDepthSampleCounts`

- If `usage` includes `VK_IMAGE_USAGE_SAMPLED_BIT`, and `format` is an integer format, a superset of `VkPhysicalDeviceLimits`::`sampledImageIntegerSampleCounts`

- If `usage` includes `VK_IMAGE_USAGE_STORAGE_BIT`, a superset of `VkPhysicalDeviceLimits`::`storageImageSampleCounts`

If multiple bits are set in `usage`, `sampleCounts` will be the intersection of the per-usage values described above.

If none of the bits described above are set in `usage`, then there is no corresponding limit in `VkPhysicalDeviceLimits`. In this case, `sampleCounts` must include at least `VK_SAMPLE_COUNT_1_BIT`.

#### 40.1.2. Allowed Extent Values Based On Image Type

Implementations may support extent values larger than the required minimum/maximum values for certain types of images subject to the constraints below.

| Note Implementations must support images with dimensions up to the required minimum/maximum values for all types of images. It follows that the query for additional capabilities must return extent values that are at least as large as the required values.

For `VK_IMAGE_TYPE_1D`:

- `maxExtent.width` ≥ VkPhysicalDeviceLimits.`maxImageDimension1D`

- `maxExtent.height` = 1

- `maxExtent.depth` = 1

For `VK_IMAGE_TYPE_2D` when `flags` does not contain `VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT`:

- `maxExtent.width` ≥ VkPhysicalDeviceLimits.`maxImageDimension2D`

- `maxExtent.height` ≥ VkPhysicalDeviceLimits.`maxImageDimension2D`

- `maxExtent.depth` = 1

For `VK_IMAGE_TYPE_2D` when `flags` contains `VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT`:

- `maxExtent.width` ≥ VkPhysicalDeviceLimits.`maxImageDimensionCube`

- `maxExtent.height` ≥ VkPhysicalDeviceLimits.`maxImageDimensionCube`

- `maxExtent.depth` = 1

For `VK_IMAGE_TYPE_3D`:

- `maxExtent.width` ≥ VkPhysicalDeviceLimits.`maxImageDimension3D`

- `maxExtent.height` ≥ VkPhysicalDeviceLimits.`maxImageDimension3D`

- `maxExtent.depth` ≥ VkPhysicalDeviceLimits.`maxImageDimension3D`

### 40.2. Additional Buffer Capabilities

To query the external handle types supported by buffers, call:

    void vkGetPhysicalDeviceExternalBufferProperties(
        VkPhysicalDevice                            physicalDevice,
        const VkPhysicalDeviceExternalBufferInfo*   pExternalBufferInfo,
        VkExternalBufferProperties*                 pExternalBufferProperties);

or the equivalent command

    void vkGetPhysicalDeviceExternalBufferPropertiesKHR(
        VkPhysicalDevice                            physicalDevice,
        const VkPhysicalDeviceExternalBufferInfo*   pExternalBufferInfo,
        VkExternalBufferProperties*                 pExternalBufferProperties);

- `physicalDevice` is the physical device from which to query the buffer capabilities.

- `pExternalBufferInfo` is a pointer to a VkPhysicalDeviceExternalBufferInfo structure describing the parameters that would be consumed by vkCreateBuffer.

- `pExternalBufferProperties` is a pointer to a VkExternalBufferProperties structure in which capabilities are returned.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pExternalBufferInfo` must be a valid pointer to a valid VkPhysicalDeviceExternalBufferInfo structure

- `pExternalBufferProperties` must be a valid pointer to a VkExternalBufferProperties structure

The `VkPhysicalDeviceExternalBufferInfo` structure is defined as:

    typedef struct VkPhysicalDeviceExternalBufferInfo {
        VkStructureType                       sType;
        const void*                           pNext;
        VkBufferCreateFlags                   flags;
        VkBufferUsageFlags                    usage;
        VkExternalMemoryHandleTypeFlagBits    handleType;
    } VkPhysicalDeviceExternalBufferInfo;

or the equivalent

    typedef VkPhysicalDeviceExternalBufferInfo VkPhysicalDeviceExternalBufferInfoKHR;

- `sType` is the type of this structure

- `pNext` is NULL or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkBufferCreateFlagBits describing additional parameters of the buffer, corresponding to VkBufferCreateInfo::`flags`.

- `usage` is a bitmask of VkBufferUsageFlagBits describing the intended usage of the buffer, corresponding to VkBufferCreateInfo::`usage`.

- `handleType` is a VkExternalMemoryHandleTypeFlagBits value specifying the memory handle type that will be used with the memory associated with the buffer.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_BUFFER_INFO`

- `pNext` must be `NULL`

- `flags` must be a valid combination of VkBufferCreateFlagBits values

- `usage` must be a valid combination of VkBufferUsageFlagBits values

- `usage` must not be `0`

- `handleType` must be a valid VkExternalMemoryHandleTypeFlagBits value

The `VkExternalBufferProperties` structure is defined as:

    typedef struct VkExternalBufferProperties {
        VkStructureType               sType;
        void*                         pNext;
        VkExternalMemoryProperties    externalMemoryProperties;
    } VkExternalBufferProperties;

or the equivalent

    typedef VkExternalBufferProperties VkExternalBufferPropertiesKHR;

- `sType` is the type of this structure

- `pNext` is NULL or a pointer to an extension-specific structure.

- `externalMemoryProperties` is a VkExternalMemoryProperties structure specifying various capabilities of the external handle type when used with the specified buffer creation parameters.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_EXTERNAL_BUFFER_PROPERTIES`

- `pNext` must be `NULL`

### 40.3. Optional Semaphore Capabilities

Semaphores may support import and export of their payload to external handles. To query the external handle types supported by semaphores, call:

    void vkGetPhysicalDeviceExternalSemaphoreProperties(
        VkPhysicalDevice                            physicalDevice,
        const VkPhysicalDeviceExternalSemaphoreInfo* pExternalSemaphoreInfo,
        VkExternalSemaphoreProperties*              pExternalSemaphoreProperties);

or the equivalent command

    void vkGetPhysicalDeviceExternalSemaphorePropertiesKHR(
        VkPhysicalDevice                            physicalDevice,
        const VkPhysicalDeviceExternalSemaphoreInfo* pExternalSemaphoreInfo,
        VkExternalSemaphoreProperties*              pExternalSemaphoreProperties);

- `physicalDevice` is the physical device from which to query the semaphore capabilities.

- `pExternalSemaphoreInfo` is a pointer to a VkPhysicalDeviceExternalSemaphoreInfo structure describing the parameters that would be consumed by vkCreateSemaphore.

- `pExternalSemaphoreProperties` is a pointer to a VkExternalSemaphoreProperties structure in which capabilities are returned.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pExternalSemaphoreInfo` must be a valid pointer to a valid VkPhysicalDeviceExternalSemaphoreInfo structure

- `pExternalSemaphoreProperties` must be a valid pointer to a VkExternalSemaphoreProperties structure

The `VkPhysicalDeviceExternalSemaphoreInfo` structure is defined as:

    typedef struct VkPhysicalDeviceExternalSemaphoreInfo {
        VkStructureType                          sType;
        const void*                              pNext;
        VkExternalSemaphoreHandleTypeFlagBits    handleType;
    } VkPhysicalDeviceExternalSemaphoreInfo;

or the equivalent

    typedef VkPhysicalDeviceExternalSemaphoreInfo VkPhysicalDeviceExternalSemaphoreInfoKHR;

- `sType` is the type of this structure

- `pNext` is NULL or a pointer to an extension-specific structure.

- `handleType` is a VkExternalSemaphoreHandleTypeFlagBits value specifying the external semaphore handle type for which capabilities will be returned.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_SEMAPHORE_INFO`

- `pNext` must be `NULL` or a pointer to a valid instance of VkSemaphoreTypeCreateInfo

- The `sType` value of each struct in the `pNext` chain must be unique

- `handleType` must be a valid VkExternalSemaphoreHandleTypeFlagBits value

Bits which may be set in VkPhysicalDeviceExternalSemaphoreInfo::`handleType`, specifying an external semaphore handle type, are:

    typedef enum VkExternalSemaphoreHandleTypeFlagBits {
        VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_FD_BIT = 0x00000001,
        VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_BIT = 0x00000002,
        VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT = 0x00000004,
        VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D12_FENCE_BIT = 0x00000008,
        VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BIT = 0x00000010,
        VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_FD_BIT_KHR = VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_FD_BIT,
        VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_BIT_KHR = VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_BIT,
        VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT_KHR = VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT,
        VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D12_FENCE_BIT_KHR = VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D12_FENCE_BIT,
        VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BIT_KHR = VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BIT,
        VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkExternalSemaphoreHandleTypeFlagBits;

or the equivalent

    typedef VkExternalSemaphoreHandleTypeFlagBits VkExternalSemaphoreHandleTypeFlagBitsKHR;

- `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_FD_BIT` specifies a POSIX file descriptor handle that has only limited valid usage outside of Vulkan and other compatible APIs. It must be compatible with the POSIX system calls `dup`, `dup2`, `close`, and the non-standard system call `dup3`. Additionally, it must be transportable over a socket using an `SCM_RIGHTS` control message. It owns a reference to the underlying synchronization primitive represented by its Vulkan semaphore object.

- `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_BIT` specifies an NT handle that has only limited valid usage outside of Vulkan and other compatible APIs. It must be compatible with the functions `DuplicateHandle`, `CloseHandle`, `CompareObjectHandles`, `GetHandleInformation`, and `SetHandleInformation`. It owns a reference to the underlying synchronization primitive represented by its Vulkan semaphore object.

- `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT` specifies a global share handle that has only limited valid usage outside of Vulkan and other compatible APIs. It is not compatible with any native APIs. It does not own a reference to the underlying synchronization primitive represented its Vulkan semaphore object, and will therefore become invalid when all Vulkan semaphore objects associated with it are destroyed.

- `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D12_FENCE_BIT` specifies an NT handle returned by `ID3D12Device`::`CreateSharedHandle` referring to a Direct3D 12 fence. It owns a reference to the underlying synchronization primitive associated with the Direct3D fence.

- `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BIT` specifies a POSIX file descriptor handle to a Linux Sync File or Android Fence object. It can be used with any native API accepting a valid sync file or fence as input. It owns a reference to the underlying synchronization primitive associated with the file descriptor. Implementations which support importing this handle type must accept any type of sync or fence FD supported by the native system they are running on.

| Note Handles of type `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BIT` generated by the implementation may represent either Linux Sync Files or Android Fences at the implementation’s discretion. Applications should only use operations defined for both types of file descriptors, unless they know via means external to Vulkan the type of the file descriptor, or are prepared to deal with the system-defined operation failures resulting from using the wrong type.

Some external semaphore handle types can only be shared within the same underlying physical device and/or the same driver version, as defined in the following table:

Table 71. External semaphore handle types compatibility
Handle type | `VkPhysicalDeviceIDProperties`::`driverUUID` | `VkPhysicalDeviceIDProperties`::`deviceUUID`
`VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_FD_BIT` | Must match | Must match
`VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_BIT` | Must match | Must match
`VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT` | Must match | Must match
`VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D12_FENCE_BIT` | Must match | Must match
`VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BIT` | No restriction | No restriction

    typedef VkFlags VkExternalSemaphoreHandleTypeFlags;

or the equivalent

    typedef VkExternalSemaphoreHandleTypeFlags VkExternalSemaphoreHandleTypeFlagsKHR;

`VkExternalSemaphoreHandleTypeFlags` is a bitmask type for setting a mask of zero or more VkExternalSemaphoreHandleTypeFlagBits.

The `VkExternalSemaphoreProperties` structure is defined as:

    typedef struct VkExternalSemaphoreProperties {
        VkStructureType                       sType;
        void*                                 pNext;
        VkExternalSemaphoreHandleTypeFlags    exportFromImportedHandleTypes;
        VkExternalSemaphoreHandleTypeFlags    compatibleHandleTypes;
        VkExternalSemaphoreFeatureFlags       externalSemaphoreFeatures;
    } VkExternalSemaphoreProperties;

or the equivalent

    typedef VkExternalSemaphoreProperties VkExternalSemaphorePropertiesKHR;

- `exportFromImportedHandleTypes` is a bitmask of VkExternalSemaphoreHandleTypeFlagBits specifying which types of imported handle `handleType` can be exported from.

- `compatibleHandleTypes` is a bitmask of VkExternalSemaphoreHandleTypeFlagBits specifying handle types which can be specified at the same time as `handleType` when creating a semaphore.

- `externalSemaphoreFeatures` is a bitmask of VkExternalSemaphoreFeatureFlagBits describing the features of `handleType`.

If `handleType` is not supported by the implementation, then VkExternalSemaphoreProperties::`externalSemaphoreFeatures` will be set to zero.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_EXTERNAL_SEMAPHORE_PROPERTIES`

- `pNext` must be `NULL`

Possible values of VkExternalSemaphoreProperties::`externalSemaphoreFeatures`, specifying the features of an external semaphore handle type, are:

    typedef enum VkExternalSemaphoreFeatureFlagBits {
        VK_EXTERNAL_SEMAPHORE_FEATURE_EXPORTABLE_BIT = 0x00000001,
        VK_EXTERNAL_SEMAPHORE_FEATURE_IMPORTABLE_BIT = 0x00000002,
        VK_EXTERNAL_SEMAPHORE_FEATURE_EXPORTABLE_BIT_KHR = VK_EXTERNAL_SEMAPHORE_FEATURE_EXPORTABLE_BIT,
        VK_EXTERNAL_SEMAPHORE_FEATURE_IMPORTABLE_BIT_KHR = VK_EXTERNAL_SEMAPHORE_FEATURE_IMPORTABLE_BIT,
        VK_EXTERNAL_SEMAPHORE_FEATURE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkExternalSemaphoreFeatureFlagBits;

or the equivalent

    typedef VkExternalSemaphoreFeatureFlagBits VkExternalSemaphoreFeatureFlagBitsKHR;

- `VK_EXTERNAL_SEMAPHORE_FEATURE_EXPORTABLE_BIT` specifies that handles of this type can be exported from Vulkan semaphore objects.

- `VK_EXTERNAL_SEMAPHORE_FEATURE_IMPORTABLE_BIT` specifies that handles of this type can be imported as Vulkan semaphore objects.

    typedef VkFlags VkExternalSemaphoreFeatureFlags;

or the equivalent

    typedef VkExternalSemaphoreFeatureFlags VkExternalSemaphoreFeatureFlagsKHR;

`VkExternalSemaphoreFeatureFlags` is a bitmask type for setting a mask of zero or more VkExternalSemaphoreFeatureFlagBits.

### 40.4. Optional Fence Capabilities

Fences may support import and export of their payload to external handles. To query the external handle types supported by fences, call:

    void vkGetPhysicalDeviceExternalFenceProperties(
        VkPhysicalDevice                            physicalDevice,
        const VkPhysicalDeviceExternalFenceInfo*    pExternalFenceInfo,
        VkExternalFenceProperties*                  pExternalFenceProperties);

or the equivalent command

    void vkGetPhysicalDeviceExternalFencePropertiesKHR(
        VkPhysicalDevice                            physicalDevice,
        const VkPhysicalDeviceExternalFenceInfo*    pExternalFenceInfo,
        VkExternalFenceProperties*                  pExternalFenceProperties);

- `physicalDevice` is the physical device from which to query the fence capabilities.

- `pExternalFenceInfo` is a pointer to a VkPhysicalDeviceExternalFenceInfo structure describing the parameters that would be consumed by vkCreateFence.

- `pExternalFenceProperties` is a pointer to a VkExternalFenceProperties structure in which capabilities are returned.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pExternalFenceInfo` must be a valid pointer to a valid VkPhysicalDeviceExternalFenceInfo structure

- `pExternalFenceProperties` must be a valid pointer to a VkExternalFenceProperties structure

The `VkPhysicalDeviceExternalFenceInfo` structure is defined as:

    typedef struct VkPhysicalDeviceExternalFenceInfo {
        VkStructureType                      sType;
        const void*                          pNext;
        VkExternalFenceHandleTypeFlagBits    handleType;
    } VkPhysicalDeviceExternalFenceInfo;

or the equivalent

    typedef VkPhysicalDeviceExternalFenceInfo VkPhysicalDeviceExternalFenceInfoKHR;

- `sType` is the type of this structure

- `pNext` is NULL or a pointer to an extension-specific structure.

- `handleType` is a VkExternalFenceHandleTypeFlagBits value indicating an external fence handle type for which capabilities will be returned.

| Note Handles of type `VK_EXTERNAL_FENCE_HANDLE_TYPE_SYNC_FD_BIT` generated by the implementation may represent either Linux Sync Files or Android Fences at the implementation’s discretion. Applications should only use operations defined for both types of file descriptors, unless they know via means external to Vulkan the type of the file descriptor, or are prepared to deal with the system-defined operation failures resulting from using the wrong type.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_FENCE_INFO`

- `pNext` must be `NULL`

- `handleType` must be a valid VkExternalFenceHandleTypeFlagBits value

Bits which may be set in VkPhysicalDeviceExternalFenceInfo::`handleType`, and in the `exportFromImportedHandleTypes` and `compatibleHandleTypes` members of VkExternalFenceProperties, to indicate external fence handle types, are:

    typedef enum VkExternalFenceHandleTypeFlagBits {
        VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_FD_BIT = 0x00000001,
        VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_BIT = 0x00000002,
        VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT = 0x00000004,
        VK_EXTERNAL_FENCE_HANDLE_TYPE_SYNC_FD_BIT = 0x00000008,
        VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_FD_BIT_KHR = VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_FD_BIT,
        VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_BIT_KHR = VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_BIT,
        VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT_KHR = VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT,
        VK_EXTERNAL_FENCE_HANDLE_TYPE_SYNC_FD_BIT_KHR = VK_EXTERNAL_FENCE_HANDLE_TYPE_SYNC_FD_BIT,
        VK_EXTERNAL_FENCE_HANDLE_TYPE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkExternalFenceHandleTypeFlagBits;

or the equivalent

    typedef VkExternalFenceHandleTypeFlagBits VkExternalFenceHandleTypeFlagBitsKHR;

- `VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_FD_BIT` specifies a POSIX file descriptor handle that has only limited valid usage outside of Vulkan and other compatible APIs. It must be compatible with the POSIX system calls `dup`, `dup2`, `close`, and the non-standard system call `dup3`. Additionally, it must be transportable over a socket using an `SCM_RIGHTS` control message. It owns a reference to the underlying synchronization primitive represented by its Vulkan fence object.

- `VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_BIT` specifies an NT handle that has only limited valid usage outside of Vulkan and other compatible APIs. It must be compatible with the functions `DuplicateHandle`, `CloseHandle`, `CompareObjectHandles`, `GetHandleInformation`, and `SetHandleInformation`. It owns a reference to the underlying synchronization primitive represented by its Vulkan fence object.

- `VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT` specifies a global share handle that has only limited valid usage outside of Vulkan and other compatible APIs. It is not compatible with any native APIs. It does not own a reference to the underlying synchronization primitive represented by its Vulkan fence object, and will therefore become invalid when all Vulkan fence objects associated with it are destroyed.

- `VK_EXTERNAL_FENCE_HANDLE_TYPE_SYNC_FD_BIT` specifies a POSIX file descriptor handle to a Linux Sync File or Android Fence. It can be used with any native API accepting a valid sync file or fence as input. It owns a reference to the underlying synchronization primitive associated with the file descriptor. Implementations which support importing this handle type must accept any type of sync or fence FD supported by the native system they are running on.

Some external fence handle types can only be shared within the same underlying physical device and/or the same driver version, as defined in the following table:

Table 72. External fence handle types compatibility
Handle type | `VkPhysicalDeviceIDProperties`::`driverUUID` | `VkPhysicalDeviceIDProperties`::`deviceUUID`
`VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_FD_BIT` | Must match | Must match
`VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_BIT` | Must match | Must match
`VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT` | Must match | Must match
`VK_EXTERNAL_FENCE_HANDLE_TYPE_SYNC_FD_BIT` | No restriction | No restriction

    typedef VkFlags VkExternalFenceHandleTypeFlags;

or the equivalent

    typedef VkExternalFenceHandleTypeFlags VkExternalFenceHandleTypeFlagsKHR;

`VkExternalFenceHandleTypeFlags` is a bitmask type for setting a mask of zero or more VkExternalFenceHandleTypeFlagBits.

The `VkExternalFenceProperties` structure is defined as:

    typedef struct VkExternalFenceProperties {
        VkStructureType                   sType;
        void*                             pNext;
        VkExternalFenceHandleTypeFlags    exportFromImportedHandleTypes;
        VkExternalFenceHandleTypeFlags    compatibleHandleTypes;
        VkExternalFenceFeatureFlags       externalFenceFeatures;
    } VkExternalFenceProperties;

or the equivalent

    typedef VkExternalFenceProperties VkExternalFencePropertiesKHR;

- `exportFromImportedHandleTypes` is a bitmask of VkExternalFenceHandleTypeFlagBits indicating which types of imported handle `handleType` can be exported from.

- `compatibleHandleTypes` is a bitmask of VkExternalFenceHandleTypeFlagBits specifying handle types which can be specified at the same time as `handleType` when creating a fence.

- `externalFenceFeatures` is a bitmask of VkExternalFenceFeatureFlagBits indicating the features of `handleType`.

If `handleType` is not supported by the implementation, then VkExternalFenceProperties::`externalFenceFeatures` will be set to zero.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_EXTERNAL_FENCE_PROPERTIES`

- `pNext` must be `NULL`

Bits which may be set in VkExternalFenceProperties::`externalFenceFeatures`, indicating features of a fence external handle type, are:

    typedef enum VkExternalFenceFeatureFlagBits {
        VK_EXTERNAL_FENCE_FEATURE_EXPORTABLE_BIT = 0x00000001,
        VK_EXTERNAL_FENCE_FEATURE_IMPORTABLE_BIT = 0x00000002,
        VK_EXTERNAL_FENCE_FEATURE_EXPORTABLE_BIT_KHR = VK_EXTERNAL_FENCE_FEATURE_EXPORTABLE_BIT,
        VK_EXTERNAL_FENCE_FEATURE_IMPORTABLE_BIT_KHR = VK_EXTERNAL_FENCE_FEATURE_IMPORTABLE_BIT,
        VK_EXTERNAL_FENCE_FEATURE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
    } VkExternalFenceFeatureFlagBits;

or the equivalent

    typedef VkExternalFenceFeatureFlagBits VkExternalFenceFeatureFlagBitsKHR;

- `VK_EXTERNAL_FENCE_FEATURE_EXPORTABLE_BIT` specifies handles of this type can be exported from Vulkan fence objects.

- `VK_EXTERNAL_FENCE_FEATURE_IMPORTABLE_BIT` specifies handles of this type can be imported to Vulkan fence objects.

    typedef VkFlags VkExternalFenceFeatureFlags;

or the equivalent

    typedef VkExternalFenceFeatureFlags VkExternalFenceFeatureFlagsKHR;

`VkExternalFenceFeatureFlags` is a bitmask type for setting a mask of zero or more VkExternalFenceFeatureFlagBits.

### 40.5. Timestamp Calibration Capabilities

To query the set of time domains for which a physical device supports timestamp calibration, call:

    VkResult vkGetPhysicalDeviceCalibrateableTimeDomainsEXT(
        VkPhysicalDevice                            physicalDevice,
        uint32_t*                                   pTimeDomainCount,
        VkTimeDomainEXT*                            pTimeDomains);

- `physicalDevice` is the physical device from which to query the set of calibrateable time domains.

- `pTimeDomainCount` is a pointer to an integer related to the number of calibrateable time domains available or queried, as described below.

- `pTimeDomains` is either `NULL` or a pointer to an array of VkTimeDomainEXT values, indicating the supported calibrateable time domains.

If `pTimeDomains` is `NULL`, then the number of calibrateable time domains supported for the given `physicalDevice` is returned in `pTimeDomainCount`. Otherwise, `pTimeDomainCount` must point to a variable set by the user to the number of elements in the `pTimeDomains` array, and on return the variable is overwritten with the number of values actually written to `pTimeDomains`. If the value of `pTimeDomainCount` is less than the number of calibrateable time domains supported, at most `pTimeDomainCount` values will be written to `pTimeDomains`. If `pTimeDomainCount` is smaller than the number of calibrateable time domains supported for the given `physicalDevice`, `VK_INCOMPLETE` will be returned instead of `VK_SUCCESS` to indicate that not all the available values were returned.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pTimeDomainCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pTimeDomainCount` is not `0`, and `pTimeDomains` is not `NULL`, `pTimeDomains` must be a valid pointer to an array of `pTimeDomainCount` VkTimeDomainEXT values

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

## 41. Debugging

To aid developers in tracking down errors in the application’s use of Vulkan, particularly in combination with an external debugger or profiler, debugging extensions may be available.

The VkObjectType enumeration defines values, each of which corresponds to a specific Vulkan handle type. These values can be used to associate debug information with a particular type of object through one or more extensions.

    typedef enum VkObjectType {
        VK_OBJECT_TYPE_UNKNOWN = 0,
        VK_OBJECT_TYPE_INSTANCE = 1,
        VK_OBJECT_TYPE_PHYSICAL_DEVICE = 2,
        VK_OBJECT_TYPE_DEVICE = 3,
        VK_OBJECT_TYPE_QUEUE = 4,
        VK_OBJECT_TYPE_SEMAPHORE = 5,
        VK_OBJECT_TYPE_COMMAND_BUFFER = 6,
        VK_OBJECT_TYPE_FENCE = 7,
        VK_OBJECT_TYPE_DEVICE_MEMORY = 8,
        VK_OBJECT_TYPE_BUFFER = 9,
        VK_OBJECT_TYPE_IMAGE = 10,
        VK_OBJECT_TYPE_EVENT = 11,
        VK_OBJECT_TYPE_QUERY_POOL = 12,
        VK_OBJECT_TYPE_BUFFER_VIEW = 13,
        VK_OBJECT_TYPE_IMAGE_VIEW = 14,
        VK_OBJECT_TYPE_SHADER_MODULE = 15,
        VK_OBJECT_TYPE_PIPELINE_CACHE = 16,
        VK_OBJECT_TYPE_PIPELINE_LAYOUT = 17,
        VK_OBJECT_TYPE_RENDER_PASS = 18,
        VK_OBJECT_TYPE_PIPELINE = 19,
        VK_OBJECT_TYPE_DESCRIPTOR_SET_LAYOUT = 20,
        VK_OBJECT_TYPE_SAMPLER = 21,
        VK_OBJECT_TYPE_DESCRIPTOR_POOL = 22,
        VK_OBJECT_TYPE_DESCRIPTOR_SET = 23,
        VK_OBJECT_TYPE_FRAMEBUFFER = 24,
        VK_OBJECT_TYPE_COMMAND_POOL = 25,
        VK_OBJECT_TYPE_SAMPLER_YCBCR_CONVERSION = 1000156000,
        VK_OBJECT_TYPE_DESCRIPTOR_UPDATE_TEMPLATE = 1000085000,
        VK_OBJECT_TYPE_SURFACE_KHR = 1000000000,
        VK_OBJECT_TYPE_SWAPCHAIN_KHR = 1000001000,
        VK_OBJECT_TYPE_DISPLAY_KHR = 1000002000,
        VK_OBJECT_TYPE_DISPLAY_MODE_KHR = 1000002001,
        VK_OBJECT_TYPE_DEBUG_REPORT_CALLBACK_EXT = 1000011000,
        VK_OBJECT_TYPE_DEBUG_UTILS_MESSENGER_EXT = 1000128000,
        VK_OBJECT_TYPE_ACCELERATION_STRUCTURE_KHR = 1000165000,
        VK_OBJECT_TYPE_VALIDATION_CACHE_EXT = 1000160000,
        VK_OBJECT_TYPE_PERFORMANCE_CONFIGURATION_INTEL = 1000210000,
        VK_OBJECT_TYPE_DEFERRED_OPERATION_KHR = 1000268000,
        VK_OBJECT_TYPE_INDIRECT_COMMANDS_LAYOUT_NV = 1000277000,
        VK_OBJECT_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_KHR = VK_OBJECT_TYPE_DESCRIPTOR_UPDATE_TEMPLATE,
        VK_OBJECT_TYPE_SAMPLER_YCBCR_CONVERSION_KHR = VK_OBJECT_TYPE_SAMPLER_YCBCR_CONVERSION,
        VK_OBJECT_TYPE_ACCELERATION_STRUCTURE_NV = VK_OBJECT_TYPE_ACCELERATION_STRUCTURE_KHR,
        VK_OBJECT_TYPE_MAX_ENUM = 0x7FFFFFFF
    } VkObjectType;

Table 73. VkObjectType and Vulkan Handle Relationship
VkObjectType | Vulkan Handle Type
--- | ---
`VK_OBJECT_TYPE_UNKNOWN` | Unknown/Undefined Handle
`VK_OBJECT_TYPE_INSTANCE` | VkInstance
`VK_OBJECT_TYPE_PHYSICAL_DEVICE` | VkPhysicalDevice
`VK_OBJECT_TYPE_DEVICE` | VkDevice
`VK_OBJECT_TYPE_QUEUE` | VkQueue
`VK_OBJECT_TYPE_SEMAPHORE` | VkSemaphore
`VK_OBJECT_TYPE_COMMAND_BUFFER` | VkCommandBuffer
`VK_OBJECT_TYPE_FENCE` | VkFence
`VK_OBJECT_TYPE_DEVICE_MEMORY` | VkDeviceMemory
`VK_OBJECT_TYPE_BUFFER` | VkBuffer
`VK_OBJECT_TYPE_IMAGE` | VkImage
`VK_OBJECT_TYPE_EVENT` | VkEvent
`VK_OBJECT_TYPE_QUERY_POOL` | VkQueryPool
`VK_OBJECT_TYPE_BUFFER_VIEW` | VkBufferView
`VK_OBJECT_TYPE_IMAGE_VIEW` | VkImageView
`VK_OBJECT_TYPE_SHADER_MODULE` | VkShaderModule
`VK_OBJECT_TYPE_PIPELINE_CACHE` | VkPipelineCache
`VK_OBJECT_TYPE_PIPELINE_LAYOUT` | VkPipelineLayout
`VK_OBJECT_TYPE_RENDER_PASS` | VkRenderPass
`VK_OBJECT_TYPE_PIPELINE` | VkPipeline
`VK_OBJECT_TYPE_DESCRIPTOR_SET_LAYOUT` | VkDescriptorSetLayout
`VK_OBJECT_TYPE_SAMPLER` | VkSampler
`VK_OBJECT_TYPE_DESCRIPTOR_POOL` | VkDescriptorPool
`VK_OBJECT_TYPE_DESCRIPTOR_SET` | VkDescriptorSet
`VK_OBJECT_TYPE_FRAMEBUFFER` | VkFramebuffer
`VK_OBJECT_TYPE_COMMAND_POOL` | VkCommandPool
`VK_OBJECT_TYPE_SAMPLER_YCBCR_CONVERSION` | VkSamplerYcbcrConversion
`VK_OBJECT_TYPE_DESCRIPTOR_UPDATE_TEMPLATE` | VkDescriptorUpdateTemplate
`VK_OBJECT_TYPE_SURFACE_KHR` | VkSurfaceKHR
`VK_OBJECT_TYPE_SWAPCHAIN_KHR` | VkSwapchainKHR
`VK_OBJECT_TYPE_DISPLAY_KHR` | VkDisplayKHR
`VK_OBJECT_TYPE_DISPLAY_MODE_KHR` | VkDisplayModeKHR
`VK_OBJECT_TYPE_DEBUG_REPORT_CALLBACK_EXT` | VkDebugReportCallbackEXT
`VK_OBJECT_TYPE_INDIRECT_COMMANDS_LAYOUT_NV` | VkIndirectCommandsLayoutNV
`VK_OBJECT_TYPE_DEBUG_UTILS_MESSENGER_EXT` | VkDebugUtilsMessengerEXT
`VK_OBJECT_TYPE_VALIDATION_CACHE_EXT` | VkValidationCacheEXT
`VK_OBJECT_TYPE_ACCELERATION_STRUCTURE_KHR` | VkAccelerationStructureKHR
`VK_OBJECT_TYPE_PERFORMANCE_CONFIGURATION_INTEL` | VkPerformanceConfigurationINTEL

If this Specification was generated with any such extensions included, they will be described in the remainder of this chapter.

### 41.1. Debug Utilities

Vulkan provides flexible debugging utilities for debugging an application.

The Object Debug Annotation section describes how to associate either a name or binary data with a specific Vulkan object.

The Queue Labels section describes how to annotate and group the work submitted to a queue.

The Command Buffer Labels section describes how to associate logical elements of the scene with commands in a VkCommandBuffer.

The Debug Messengers section describes how to create debug messenger objects associated with an application supplied callback to capture debug messages from a variety of Vulkan components.

#### 41.1.1. Object Debug Annotation

It can be useful for an application to provide its own content relative to a specific Vulkan object. The following commands allow application developers to associate user-defined information with Vulkan objects.

##### Object Naming

An object can be provided a user-defined name by calling `vkSetDebugUtilsObjectNameEXT` as defined below.

    VkResult vkSetDebugUtilsObjectNameEXT(
        VkDevice                                    device,
        const VkDebugUtilsObjectNameInfoEXT*        pNameInfo);

- `device` is the device that created the object.

- `pNameInfo` is a pointer to a VkDebugUtilsObjectNameInfoEXT structure specifying parameters of the name to set on the object.

Valid Usage

- `pNameInfo->objectType` must not be `VK_OBJECT_TYPE_UNKNOWN`

- `pNameInfo->objectHandle` must not be VK_NULL_HANDLE

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pNameInfo` must be a valid pointer to a valid VkDebugUtilsObjectNameInfoEXT structure

Host Synchronization

- Host access to `pNameInfo.objectHandle` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkDebugUtilsObjectNameInfoEXT` structure is defined as:

    typedef struct VkDebugUtilsObjectNameInfoEXT {
        VkStructureType    sType;
        const void*        pNext;
        VkObjectType       objectType;
        uint64_t           objectHandle;
        const char*        pObjectName;
    } VkDebugUtilsObjectNameInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `objectType` is a VkObjectType specifying the type of the object to be named.

- `objectHandle` is the object to be named.

- `pObjectName` is a null-terminated UTF-8 string specifying the name to apply to `objectHandle`.

Applications may change the name associated with an object simply by calling `vkSetDebugUtilsObjectNameEXT` again with a new string. If `pObjectName` is an empty string, then any previously set name is removed.

Valid Usage

- If `objectType` is `VK_OBJECT_TYPE_UNKNOWN`, `objectHandle` must not be VK_NULL_HANDLE

- If `objectType` is not `VK_OBJECT_TYPE_UNKNOWN`, `objectHandle` must be VK_NULL_HANDLE or a valid Vulkan handle of the type associated with `objectType` as defined in the VkObjectType and Vulkan Handle Relationship table

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEBUG_UTILS_OBJECT_NAME_INFO_EXT`

- `pNext` must be `NULL`

- `objectType` must be a valid VkObjectType value

- `pObjectName` must be a null-terminated UTF-8 string

##### Object Data Association

In addition to setting a name for an object, debugging and validation layers may have uses for additional binary data on a per-object basis that have no other place in the Vulkan API.

For example, a `VkShaderModule` could have additional debugging data attached to it to aid in offline shader tracing.

Additional data can be attached to an object by calling `vkSetDebugUtilsObjectTagEXT` as defined below.

    VkResult vkSetDebugUtilsObjectTagEXT(
        VkDevice                                    device,
        const VkDebugUtilsObjectTagInfoEXT*         pTagInfo);

- `device` is the device that created the object.

- `pTagInfo` is a pointer to a VkDebugUtilsObjectTagInfoEXT structure specifying parameters of the tag to attach to the object.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pTagInfo` must be a valid pointer to a valid VkDebugUtilsObjectTagInfoEXT structure

Host Synchronization

- Host access to `pTagInfo.objectHandle` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkDebugUtilsObjectTagInfoEXT` structure is defined as:

    typedef struct VkDebugUtilsObjectTagInfoEXT {
        VkStructureType    sType;
        const void*        pNext;
        VkObjectType       objectType;
        uint64_t           objectHandle;
        uint64_t           tagName;
        size_t             tagSize;
        const void*        pTag;
    } VkDebugUtilsObjectTagInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `objectType` is a VkObjectType specifying the type of the object to be named.

- `objectHandle` is the object to be tagged.

- `tagName` is a numerical identifier of the tag.

- `tagSize` is the number of bytes of data to attach to the object.

- `pTag` is a pointer to an array of `tagSize` bytes containing the data to be associated with the object.

The `tagName` parameter gives a name or identifier to the type of data being tagged. This can be used by debugging layers to easily filter for only data that can be used by that implementation.

Valid Usage

- `objectType` must not be `VK_OBJECT_TYPE_UNKNOWN`

- `objectHandle` must be a valid Vulkan handle of the type associated with `objectType` as defined in the VkObjectType and Vulkan Handle Relationship table

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEBUG_UTILS_OBJECT_TAG_INFO_EXT`

- `pNext` must be `NULL`

- `objectType` must be a valid VkObjectType value

- `pTag` must be a valid pointer to an array of `tagSize` bytes

- `tagSize` must be greater than `0`

#### 41.1.2. Queue Labels

All Vulkan work must be submitted using queues. It is possible for an application to use multiple queues, each containing multiple command buffers, when performing work. It can be useful to identify which queue, or even where in a queue, something has occurred.

To begin identifying a region using a debug label inside a queue, you may use the vkQueueBeginDebugUtilsLabelEXT command.

Then, when the region of interest has passed, you may end the label region using vkQueueEndDebugUtilsLabelEXT.

Additionally, a single debug label may be inserted at any time using vkQueueInsertDebugUtilsLabelEXT.

A queue debug label region is opened by calling:

    void vkQueueBeginDebugUtilsLabelEXT(
        VkQueue                                     queue,
        const VkDebugUtilsLabelEXT*                 pLabelInfo);

- `queue` is the queue in which to start a debug label region.

- `pLabelInfo` is a pointer to a VkDebugUtilsLabelEXT structure specifying parameters of the label region to open.

Valid Usage (Implicit)

- `queue` must be a valid VkQueue handle

- `pLabelInfo` must be a valid pointer to a valid VkDebugUtilsLabelEXT structure

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
- | - | Any | -

The `VkDebugUtilsLabelEXT` structure is defined as:

    typedef struct VkDebugUtilsLabelEXT {
        VkStructureType    sType;
        const void*        pNext;
        const char*        pLabelName;
        float              color[4];
    } VkDebugUtilsLabelEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `pLabelName` is a pointer to a null-terminated UTF-8 string containing the name of the label.

- `color` is an optional RGBA color value that can be associated with the label. A particular implementation may choose to ignore this color value. The values contain RGBA values in order, in the range 0.0 to 1.0. If all elements in `color` are set to 0.0 then it is ignored.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEBUG_UTILS_LABEL_EXT`

- `pNext` must be `NULL`

- `pLabelName` must be a null-terminated UTF-8 string

A queue debug label region is closed by calling:

    void vkQueueEndDebugUtilsLabelEXT(
        VkQueue                                     queue);

- `queue` is the queue in which a debug label region should be closed.

The calls to vkQueueBeginDebugUtilsLabelEXT and vkQueueEndDebugUtilsLabelEXT must be matched and balanced.

Valid Usage

- There must be an outstanding `vkQueueBeginDebugUtilsLabelEXT` command prior to the `vkQueueEndDebugUtilsLabelEXT` on the queue

Valid Usage (Implicit)

- `queue` must be a valid VkQueue handle

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
- | - | Any | -

A single label can be inserted into a queue by calling:

    void vkQueueInsertDebugUtilsLabelEXT(
        VkQueue                                     queue,
        const VkDebugUtilsLabelEXT*                 pLabelInfo);

- `queue` is the queue into which a debug label will be inserted.

- `pLabelInfo` is a pointer to a VkDebugUtilsLabelEXT structure specifying parameters of the label to insert.

Valid Usage (Implicit)

- `queue` must be a valid VkQueue handle

- `pLabelInfo` must be a valid pointer to a valid VkDebugUtilsLabelEXT structure

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
- | - | Any | -

#### 41.1.3. Command Buffer Labels

Typical Vulkan applications will submit many command buffers in each frame, with each command buffer containing a large number of individual commands. Being able to logically annotate regions of command buffers that belong together as well as hierarchically subdivide the frame is important to a developer’s ability to navigate the commands viewed holistically.

To identify the beginning of a debug label region in a command buffer, vkCmdBeginDebugUtilsLabelEXT can be used as defined below.

To indicate the end of a debug label region in a command buffer, vkCmdEndDebugUtilsLabelEXT can be used.

To insert a single command buffer debug label inside of a command buffer, vkCmdInsertDebugUtilsLabelEXT can be used as defined below.

A command buffer debug label region can be opened by calling:

    void vkCmdBeginDebugUtilsLabelEXT(
        VkCommandBuffer                             commandBuffer,
        const VkDebugUtilsLabelEXT*                 pLabelInfo);

- `commandBuffer` is the command buffer into which the command is recorded.

- `pLabelInfo` is a pointer to a VkDebugUtilsLabelEXT structure specifying parameters of the label region to open.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pLabelInfo` must be a valid pointer to a valid VkDebugUtilsLabelEXT structure

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

Host Synchronization

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute |

A command buffer label region can be closed by calling:

    void vkCmdEndDebugUtilsLabelEXT(
        VkCommandBuffer                             commandBuffer);

- `commandBuffer` is the command buffer into which the command is recorded.

An application may open a debug label region in one command buffer and close it in another, or otherwise split debug label regions across multiple command buffers or multiple queue submissions. When viewed from the linear series of submissions to a single queue, the calls to vkCmdBeginDebugUtilsLabelEXT and vkCmdEndDebugUtilsLabelEXT must be matched and balanced.

Valid Usage

- There must be an outstanding `vkCmdBeginDebugUtilsLabelEXT` command prior to the `vkCmdEndDebugUtilsLabelEXT` on the queue that `commandBuffer` is submitted to

- If `commandBuffer` is a secondary command buffer, there must be an outstanding `vkCmdBeginDebugUtilsLabelEXT` command recorded to `commandBuffer` that has not previously been ended by a call to `vkCmdEndDebugUtilsLabelEXT`.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

Host Synchronization

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute |

A single debug label can be inserted into a command buffer by calling:

    void vkCmdInsertDebugUtilsLabelEXT(
        VkCommandBuffer                             commandBuffer,
        const VkDebugUtilsLabelEXT*                 pLabelInfo);

- `commandBuffer` is the command buffer into which the command is recorded.

- `pInfo` is a pointer to a VkDebugUtilsLabelEXT structure specifying parameters of the label to insert.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pLabelInfo` must be a valid pointer to a valid VkDebugUtilsLabelEXT structure

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

Host Synchronization

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute |

#### 41.1.4. Debug Messengers

Vulkan allows an application to register multiple callbacks with any Vulkan component wishing to report debug information. Some callbacks may log the information to a file, others may cause a debug break point or other application defined behavior. A primary producer of callback messages are the validation layers. An application can register callbacks even when no validation layers are enabled, but they will only be called for the Vulkan loader and, if implemented, other layer and driver events.

A `VkDebugUtilsMessengerEXT` is a messenger object which handles passing along debug messages to a provided debug callback.

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkDebugUtilsMessengerEXT)

The debug messenger will provide detailed feedback on the application’s use of Vulkan when events of interest occur. When an event of interest does occur, the debug messenger will submit a debug message to the debug callback that was provided during its creation. Additionally, the debug messenger is responsible with filtering out debug messages that the callback is not interested in and will only provide desired debug messages.

A debug messenger triggers a debug callback with a debug message when an event of interest occurs. To create a debug messenger which will trigger a debug callback, call:

    VkResult vkCreateDebugUtilsMessengerEXT(
        VkInstance                                  instance,
        const VkDebugUtilsMessengerCreateInfoEXT*   pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkDebugUtilsMessengerEXT*                   pMessenger);

- `instance` the instance the messenger will be used with.

- `pCreateInfo` is a pointer to a VkDebugUtilsMessengerCreateInfoEXT structure containing the callback pointer, as well as defining conditions under which this messenger will trigger the callback.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pMessenger` is a pointer to a VkDebugUtilsMessengerEXT handle in which the created object is returned.

Valid Usage (Implicit)

- `instance` must be a valid VkInstance handle

- `pCreateInfo` must be a valid pointer to a valid VkDebugUtilsMessengerCreateInfoEXT structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pMessenger` must be a valid pointer to a VkDebugUtilsMessengerEXT handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

The application must ensure that vkCreateDebugUtilsMessengerEXT is not executed in parallel with any Vulkan command that is also called with `instance` or child of `instance` as the dispatchable argument.

The definition of `VkDebugUtilsMessengerCreateInfoEXT` is:

    typedef struct VkDebugUtilsMessengerCreateInfoEXT {
        VkStructureType                         sType;
        const void*                             pNext;
        VkDebugUtilsMessengerCreateFlagsEXT     flags;
        VkDebugUtilsMessageSeverityFlagsEXT     messageSeverity;
        VkDebugUtilsMessageTypeFlagsEXT         messageType;
        PFN_vkDebugUtilsMessengerCallbackEXT    pfnUserCallback;
        void*                                   pUserData;
    } VkDebugUtilsMessengerCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is 0 and reserved for future use.

- `messageSeverity` is a bitmask of VkDebugUtilsMessageSeverityFlagBitsEXT specifying which severity of event(s) will cause this callback to be called.

- `messageType` is a bitmask of VkDebugUtilsMessageTypeFlagBitsEXT specifying which type of event(s) will cause this callback to be called.

- `pfnUserCallback` is the application callback function to call.

- `pUserData` is user data to be passed to the callback.

For each `VkDebugUtilsMessengerEXT` that is created the `VkDebugUtilsMessengerCreateInfoEXT`::`messageSeverity` and `VkDebugUtilsMessengerCreateInfoEXT`::`messageType` determine when that `VkDebugUtilsMessengerCreateInfoEXT`::`pfnUserCallback` is called. The process to determine if the user’s `pfnUserCallback` is triggered when an event occurs is as follows:

1. The implementation will perform a bitwise AND of the event’s VkDebugUtilsMessageSeverityFlagBitsEXT with the `messageSeverity` provided during creation of the VkDebugUtilsMessengerEXT object.

   1. If the value is 0, the message is skipped.

2. The implementation will perform bitwise AND of the event’s VkDebugUtilsMessageTypeFlagBitsEXT with the `messageType` provided during the creation of the VkDebugUtilsMessengerEXT object.

   1. If the value is 0, the message is skipped.

3. The callback will trigger a debug message for the current event

The callback will come directly from the component that detected the event, unless some other layer intercepts the calls for its own purposes (filter them in a different way, log to a system error log, etc.).

An application can receive multiple callbacks if multiple `VkDebugUtilsMessengerEXT` objects are created. A callback will always be executed in the same thread as the originating Vulkan call.

A callback can be called from multiple threads simultaneously (if the application is making Vulkan calls from multiple threads).

Valid Usage

- `pfnUserCallback` must be a valid PFN_vkDebugUtilsMessengerCallbackEXT

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEBUG_UTILS_MESSENGER_CREATE_INFO_EXT`

- `flags` must be `0`

- `messageSeverity` must be a valid combination of VkDebugUtilsMessageSeverityFlagBitsEXT values

- `messageSeverity` must not be `0`

- `messageType` must be a valid combination of VkDebugUtilsMessageTypeFlagBitsEXT values

- `messageType` must not be `0`

- `pfnUserCallback` must be a valid PFN_vkDebugUtilsMessengerCallbackEXT value

Bits which can be set in VkDebugUtilsMessengerCreateInfoEXT::`messageSeverity`, specifying event severities which cause a debug messenger to call the callback, are:

    typedef enum VkDebugUtilsMessageSeverityFlagBitsEXT {
        VK_DEBUG_UTILS_MESSAGE_SEVERITY_VERBOSE_BIT_EXT = 0x00000001,
        VK_DEBUG_UTILS_MESSAGE_SEVERITY_INFO_BIT_EXT = 0x00000010,
        VK_DEBUG_UTILS_MESSAGE_SEVERITY_WARNING_BIT_EXT = 0x00000100,
        VK_DEBUG_UTILS_MESSAGE_SEVERITY_ERROR_BIT_EXT = 0x00001000,
        VK_DEBUG_UTILS_MESSAGE_SEVERITY_FLAG_BITS_MAX_ENUM_EXT = 0x7FFFFFFF
    } VkDebugUtilsMessageSeverityFlagBitsEXT;

- `VK_DEBUG_UTILS_MESSAGE_SEVERITY_VERBOSE_BIT_EXT` specifies the most verbose output indicating all diagnostic messages from the Vulkan loader, layers, and drivers should be captured.

- `VK_DEBUG_UTILS_MESSAGE_SEVERITY_INFO_BIT_EXT` specifies an informational message such as resource details that may be handy when debugging an application.

- `VK_DEBUG_UTILS_MESSAGE_SEVERITY_WARNING_BIT_EXT` specifies use of Vulkan that may expose an app bug. Such cases may not be immediately harmful, such as a fragment shader outputting to a location with no attachment. Other cases may point to behavior that is almost certainly bad when unintended such as using an image whose memory has not been filled. In general if you see a warning but you know that the behavior is intended/desired, then simply ignore the warning.

- `VK_DEBUG_UTILS_MESSAGE_SEVERITY_ERROR_BIT_EXT` specifies that the application has violated a valid usage condition of the specification.

| Note The values of VkDebugUtilsMessageSeverityFlagBitsEXT are sorted based on severity. The higher the flag value, the more severe the message. This allows for simple boolean operation comparisons when looking at VkDebugUtilsMessageSeverityFlagBitsEXT values. For example:
        if (messageSeverity >= VK_DEBUG_UTILS_MESSAGE_SEVERITY_WARNING_BIT_EXT) {
            // Do something for warnings and errors
        }
In addition, space has been left between the enums to allow for later addition of new severities in between the existing values.

    typedef VkFlags VkDebugUtilsMessageSeverityFlagsEXT;

`VkDebugUtilsMessageSeverityFlagsEXT` is a bitmask type for setting a mask of zero or more VkDebugUtilsMessageSeverityFlagBitsEXT.

Bits which can be set in VkDebugUtilsMessengerCreateInfoEXT::`messageType`, specifying event types which cause a debug messenger to call the callback, are:

    typedef enum VkDebugUtilsMessageTypeFlagBitsEXT {
        VK_DEBUG_UTILS_MESSAGE_TYPE_GENERAL_BIT_EXT = 0x00000001,
        VK_DEBUG_UTILS_MESSAGE_TYPE_VALIDATION_BIT_EXT = 0x00000002,
        VK_DEBUG_UTILS_MESSAGE_TYPE_PERFORMANCE_BIT_EXT = 0x00000004,
        VK_DEBUG_UTILS_MESSAGE_TYPE_FLAG_BITS_MAX_ENUM_EXT = 0x7FFFFFFF
    } VkDebugUtilsMessageTypeFlagBitsEXT;

- `VK_DEBUG_UTILS_MESSAGE_TYPE_GENERAL_BIT_EXT` specifies that some general event has occurred. This is typically a non-specification, non-performance event.

- `VK_DEBUG_UTILS_MESSAGE_TYPE_VALIDATION_BIT_EXT` specifies that something has occurred during validation against the Vulkan specification that may indicate invalid behavior.

- `VK_DEBUG_UTILS_MESSAGE_TYPE_PERFORMANCE_BIT_EXT` specifies a potentially non-optimal use of Vulkan, e.g. using vkCmdClearColorImage when setting VkAttachmentDescription::`loadOp` to `VK_ATTACHMENT_LOAD_OP_CLEAR` would have worked.

    typedef VkFlags VkDebugUtilsMessageTypeFlagsEXT;

`VkDebugUtilsMessageTypeFlagsEXT` is a bitmask type for setting a mask of zero or more VkDebugUtilsMessageTypeFlagBitsEXT.

The prototype for the VkDebugUtilsMessengerCreateInfoEXT::`pfnUserCallback` function implemented by the application is:

    typedef VkBool32 (VKAPI_PTR *PFN_vkDebugUtilsMessengerCallbackEXT)(
        VkDebugUtilsMessageSeverityFlagBitsEXT           messageSeverity,
        VkDebugUtilsMessageTypeFlagsEXT                  messageTypes,
        const VkDebugUtilsMessengerCallbackDataEXT*      pCallbackData,
        void*                                            pUserData);

- `messageSeverity` specifies the VkDebugUtilsMessageSeverityFlagBitsEXT that triggered this callback.

- `messageTypes` is a bitmask of VkDebugUtilsMessageTypeFlagBitsEXT specifying which type of event(s) triggered this callback.

- `pCallbackData` contains all the callback related data in the VkDebugUtilsMessengerCallbackDataEXT structure.

- `pUserData` is the user data provided when the VkDebugUtilsMessengerEXT was created.

The callback must not call vkDestroyDebugUtilsMessengerEXT.

The callback returns a `VkBool32`, which is interpreted in a layer-specified manner. The application should always return `VK_FALSE`. The `VK_TRUE` value is reserved for use in layer development.

The definition of `VkDebugUtilsMessengerCallbackDataEXT` is:

    typedef struct VkDebugUtilsMessengerCallbackDataEXT {
        VkStructureType                              sType;
        const void*                                  pNext;
        VkDebugUtilsMessengerCallbackDataFlagsEXT    flags;
        const char*                                  pMessageIdName;
        int32_t                                      messageIdNumber;
        const char*                                  pMessage;
        uint32_t                                     queueLabelCount;
        const VkDebugUtilsLabelEXT*                  pQueueLabels;
        uint32_t                                     cmdBufLabelCount;
        const VkDebugUtilsLabelEXT*                  pCmdBufLabels;
        uint32_t                                     objectCount;
        const VkDebugUtilsObjectNameInfoEXT*         pObjects;
    } VkDebugUtilsMessengerCallbackDataEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is 0 and reserved for future use.

- `pMessageIdName` is a null-terminated string that identifies the particular message ID that is associated with the provided message. If the message corresponds to a validation layer message, then this string may contain the portion of the Vulkan specification that is believed to have been violated.

- `messageIdNumber` is the ID number of the triggering message. If the message corresponds to a validation layer message, then this number is related to the internal number associated with the message being triggered.

- `pMessage` is a null-terminated string detailing the trigger conditions.

- `queueLabelCount` is a count of items contained in the `pQueueLabels` array.

- `pQueueLabels` is NULL or a pointer to an array of VkDebugUtilsLabelEXT active in the current `VkQueue` at the time the callback was triggered. Refer to Queue Labels for more information.

- `cmdBufLabelCount` is a count of items contained in the `pCmdBufLabels` array.

- `pCmdBufLabels` is NULL or a pointer to an array of VkDebugUtilsLabelEXT active in the current `VkCommandBuffer` at the time the callback was triggered. Refer to Command Buffer Labels for more information.

- `objectCount` is a count of items contained in the `pObjects` array.

- `pObjects` is a pointer to an array of VkDebugUtilsObjectNameInfoEXT objects related to the detected issue. The array is roughly in order or importance, but the 0th element is always guaranteed to be the most important object for this message.

| Note This structure should only be considered valid during the lifetime of the triggered callback.

Since adding queue and command buffer labels behaves like pushing and popping onto a stack, the order of both `pQueueLabels` and `pCmdBufLabels` is based on the order the labels were defined. The result is that the first label in either `pQueueLabels` or `pCmdBufLabels` will be the first defined (and therefore the oldest) while the last label in each list will be the most recent.

| Note `pQueueLabels` will only be non-NULL if one of the objects in `pObjects` can be related directly to a defined `VkQueue` which has had one or more labels associated with it. Likewise, `pCmdBufLabels` will only be non-NULL if one of the objects in `pObjects` can be related directly to a defined `VkCommandBuffer` which has had one or more labels associated with it. Additionally, while command buffer labels allow for beginning and ending across different command buffers, the debug messaging framework cannot guarantee that labels in `pCmdBufLables` will contain those defined outside of the associated command buffer. This is partially due to the fact that the association of one command buffer with another may not have been defined at the time the debug message is triggered.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEBUG_UTILS_MESSENGER_CALLBACK_DATA_EXT`

- `pNext` must be `NULL`

- `flags` must be `0`

- If `pMessageIdName` is not `NULL`, `pMessageIdName` must be a null-terminated UTF-8 string

- `pMessage` must be a null-terminated UTF-8 string

- If `queueLabelCount` is not `0`, `pQueueLabels` must be a valid pointer to an array of `queueLabelCount` valid VkDebugUtilsLabelEXT structures

- If `cmdBufLabelCount` is not `0`, `pCmdBufLabels` must be a valid pointer to an array of `cmdBufLabelCount` valid VkDebugUtilsLabelEXT structures

- If `objectCount` is not `0`, `pObjects` must be a valid pointer to an array of `objectCount` valid VkDebugUtilsObjectNameInfoEXT structures

There may be times that a user wishes to intentionally submit a debug message. To do this, call:

    void vkSubmitDebugUtilsMessageEXT(
        VkInstance                                  instance,
        VkDebugUtilsMessageSeverityFlagBitsEXT      messageSeverity,
        VkDebugUtilsMessageTypeFlagsEXT             messageTypes,
        const VkDebugUtilsMessengerCallbackDataEXT* pCallbackData);

- `instance` is the debug stream’s VkInstance.

- `messageSeverity` is the VkDebugUtilsMessageSeverityFlagBitsEXT severity of this event/message.

- `messageTypes` is a bitmask of VkDebugUtilsMessageTypeFlagBitsEXT specifying which type of event(s) to identify with this message.

- `pCallbackData` contains all the callback related data in the VkDebugUtilsMessengerCallbackDataEXT structure.

The call will propagate through the layers and generate callback(s) as indicated by the message’s flags. The parameters are passed on to the callback in addition to the `pUserData` value that was defined at the time the messenger was registered.

Valid Usage

- The `objectType` member of each element of `pCallbackData->pObjects` must not be `VK_OBJECT_TYPE_UNKNOWN`

Valid Usage (Implicit)

- `instance` must be a valid VkInstance handle

- `messageSeverity` must be a valid VkDebugUtilsMessageSeverityFlagBitsEXT value

- `messageTypes` must be a valid combination of VkDebugUtilsMessageTypeFlagBitsEXT values

- `messageTypes` must not be `0`

- `pCallbackData` must be a valid pointer to a valid VkDebugUtilsMessengerCallbackDataEXT structure

To destroy a `VkDebugUtilsMessengerEXT` object, call:

    void vkDestroyDebugUtilsMessengerEXT(
        VkInstance                                  instance,
        VkDebugUtilsMessengerEXT                    messenger,
        const VkAllocationCallbacks*                pAllocator);

- `instance` the instance where the callback was created.

- `messenger` the VkDebugUtilsMessengerEXT object to destroy. `messenger` is an externally synchronized object and must not be used on more than one thread at a time. This means that `vkDestroyDebugUtilsMessengerEXT` must not be called when a callback is active.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage

- If `VkAllocationCallbacks` were provided when `messenger` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `messenger` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `instance` must be a valid VkInstance handle

- `messenger` must be a valid VkDebugUtilsMessengerEXT handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `messenger` must have been created, allocated, or retrieved from `instance`

Host Synchronization

- Host access to `messenger` must be externally synchronized

The application must ensure that vkDestroyDebugUtilsMessengerEXT is not executed in parallel with any Vulkan command that is also called with `instance` or child of `instance` as the dispatchable argument.

### 41.2. Debug Markers

Debug markers provide a flexible way for debugging and validation layers to receive annotation and debug information.

The Object Annotation section describes how to associate a name or binary data with a Vulkan object.

The Command Buffer Markers section describes how to associate logical elements of the scene with commands in the command buffer.

#### 41.2.1. Object Annotation

The commands in this section allow application developers to associate user-defined information with Vulkan objects at will.

An object can be given a user-friendly name by calling:

    VkResult vkDebugMarkerSetObjectNameEXT(
        VkDevice                                    device,
        const VkDebugMarkerObjectNameInfoEXT*       pNameInfo);

- `device` is the device that created the object.

- `pNameInfo` is a pointer to a VkDebugMarkerObjectNameInfoEXT structure specifying the parameters of the name to set on the object.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pNameInfo` must be a valid pointer to a valid VkDebugMarkerObjectNameInfoEXT structure

Host Synchronization

- Host access to `pNameInfo.object` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkDebugMarkerObjectNameInfoEXT` structure is defined as:

    typedef struct VkDebugMarkerObjectNameInfoEXT {
        VkStructureType               sType;
        const void*                   pNext;
        VkDebugReportObjectTypeEXT    objectType;
        uint64_t                      object;
        const char*                   pObjectName;
    } VkDebugMarkerObjectNameInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `objectType` is a VkDebugReportObjectTypeEXT specifying the type of the object to be named.

- `object` is the object to be named.

- `pObjectName` is a null-terminated UTF-8 string specifying the name to apply to `object`.

Applications may change the name associated with an object simply by calling `vkDebugMarkerSetObjectNameEXT` again with a new string. To remove a previously set name, `pObjectName` should be set to an empty string.

Valid Usage

- `objectType` must not be `VK_DEBUG_REPORT_OBJECT_TYPE_UNKNOWN_EXT`

- `object` must not be VK_NULL_HANDLE

- `object` must be a Vulkan object of the type associated with `objectType` as defined in VkDebugReportObjectTypeEXT and Vulkan Handle Relationship.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEBUG_MARKER_OBJECT_NAME_INFO_EXT`

- `pNext` must be `NULL`

- `objectType` must be a valid VkDebugReportObjectTypeEXT value

- `pObjectName` must be a null-terminated UTF-8 string

In addition to setting a name for an object, debugging and validation layers may have uses for additional binary data on a per-object basis that has no other place in the Vulkan API. For example, a `VkShaderModule` could have additional debugging data attached to it to aid in offline shader tracing. To attach data to an object, call:

    VkResult vkDebugMarkerSetObjectTagEXT(
        VkDevice                                    device,
        const VkDebugMarkerObjectTagInfoEXT*        pTagInfo);

- `device` is the device that created the object.

- `pTagInfo` is a pointer to a VkDebugMarkerObjectTagInfoEXT structure specifying the parameters of the tag to attach to the object.

Valid Usage (Implicit)

- `device` must be a valid VkDevice handle

- `pTagInfo` must be a valid pointer to a valid VkDebugMarkerObjectTagInfoEXT structure

Host Synchronization

- Host access to `pTagInfo.object` must be externally synchronized

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

The `VkDebugMarkerObjectTagInfoEXT` structure is defined as:

    typedef struct VkDebugMarkerObjectTagInfoEXT {
        VkStructureType               sType;
        const void*                   pNext;
        VkDebugReportObjectTypeEXT    objectType;
        uint64_t                      object;
        uint64_t                      tagName;
        size_t                        tagSize;
        const void*                   pTag;
    } VkDebugMarkerObjectTagInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `objectType` is a VkDebugReportObjectTypeEXT specifying the type of the object to be named.

- `object` is the object to be tagged.

- `tagName` is a numerical identifier of the tag.

- `tagSize` is the number of bytes of data to attach to the object.

- `pTag` is a pointer to an array of `tagSize` bytes containing the data to be associated with the object.

The `tagName` parameter gives a name or identifier to the type of data being tagged. This can be used by debugging layers to easily filter for only data that can be used by that implementation.

Valid Usage

- `objectType` must not be `VK_DEBUG_REPORT_OBJECT_TYPE_UNKNOWN_EXT`

- `object` must not be VK_NULL_HANDLE

- `object` must be a Vulkan object of the type associated with `objectType` as defined in VkDebugReportObjectTypeEXT and Vulkan Handle Relationship.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEBUG_MARKER_OBJECT_TAG_INFO_EXT`

- `pNext` must be `NULL`

- `objectType` must be a valid VkDebugReportObjectTypeEXT value

- `pTag` must be a valid pointer to an array of `tagSize` bytes

- `tagSize` must be greater than `0`

#### 41.2.2. Command Buffer Markers

Typical Vulkan applications will submit many command buffers in each frame, with each command buffer containing a large number of individual commands. Being able to logically annotate regions of command buffers that belong together as well as hierarchically subdivide the frame is important to a developer’s ability to navigate the commands viewed holistically.

The marker commands `vkCmdDebugMarkerBeginEXT` and `vkCmdDebugMarkerEndEXT` define regions of a series of commands that are grouped together, and they can be nested to create a hierarchy. The `vkCmdDebugMarkerInsertEXT` command allows insertion of a single label within a command buffer.

A marker region can be opened by calling:

    void vkCmdDebugMarkerBeginEXT(
        VkCommandBuffer                             commandBuffer,
        const VkDebugMarkerMarkerInfoEXT*           pMarkerInfo);

- `commandBuffer` is the command buffer into which the command is recorded.

- `pMarkerInfo` is a pointer to a VkDebugMarkerMarkerInfoEXT structure specifying the parameters of the marker region to open.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pMarkerInfo` must be a valid pointer to a valid VkDebugMarkerMarkerInfoEXT structure

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

Host Synchronization

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute |

The `VkDebugMarkerMarkerInfoEXT` structure is defined as:

    typedef struct VkDebugMarkerMarkerInfoEXT {
        VkStructureType    sType;
        const void*        pNext;
        const char*        pMarkerName;
        float              color[4];
    } VkDebugMarkerMarkerInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `pMarkerName` is a pointer to a null-terminated UTF-8 string containing the name of the marker.

- `color` is an optional RGBA color value that can be associated with the marker. A particular implementation may choose to ignore this color value. The values contain RGBA values in order, in the range 0.0 to 1.0. If all elements in `color` are set to 0.0 then it is ignored.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEBUG_MARKER_MARKER_INFO_EXT`

- `pNext` must be `NULL`

- `pMarkerName` must be a null-terminated UTF-8 string

A marker region can be closed by calling:

    void vkCmdDebugMarkerEndEXT(
        VkCommandBuffer                             commandBuffer);

- `commandBuffer` is the command buffer into which the command is recorded.

An application may open a marker region in one command buffer and close it in another, or otherwise split marker regions across multiple command buffers or multiple queue submissions. When viewed from the linear series of submissions to a single queue, the calls to `vkCmdDebugMarkerBeginEXT` and `vkCmdDebugMarkerEndEXT` must be matched and balanced.

Valid Usage

- There must be an outstanding vkCmdDebugMarkerBeginEXT command prior to the `vkCmdDebugMarkerEndEXT` on the queue that `commandBuffer` is submitted to

- If `commandBuffer` is a secondary command buffer, there must be an outstanding vkCmdDebugMarkerBeginEXT command recorded to `commandBuffer` that has not previously been ended by a call to vkCmdDebugMarkerEndEXT.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

Host Synchronization

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute |

A single marker label can be inserted into a command buffer by calling:

    void vkCmdDebugMarkerInsertEXT(
        VkCommandBuffer                             commandBuffer,
        const VkDebugMarkerMarkerInfoEXT*           pMarkerInfo);

- `commandBuffer` is the command buffer into which the command is recorded.

- `pMarkerInfo` is a pointer to a VkDebugMarkerMarkerInfoEXT structure specifying the parameters of the marker to insert.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `pMarkerInfo` must be a valid pointer to a valid VkDebugMarkerMarkerInfoEXT structure

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, or compute operations

Host Synchronization

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute |

### 41.3. Debug Report Callbacks

Debug report callbacks are represented by `VkDebugReportCallbackEXT` handles:

    VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkDebugReportCallbackEXT)

Debug report callbacks give more detailed feedback on the application’s use of Vulkan when events of interest occur.

To register a debug report callback, an application uses vkCreateDebugReportCallbackEXT.

    VkResult vkCreateDebugReportCallbackEXT(
        VkInstance                                  instance,
        const VkDebugReportCallbackCreateInfoEXT*   pCreateInfo,
        const VkAllocationCallbacks*                pAllocator,
        VkDebugReportCallbackEXT*                   pCallback);

- `instance` the instance the callback will be logged on.

- `pCreateInfo` is a pointer to a VkDebugReportCallbackCreateInfoEXT structure defining the conditions under which this callback will be called.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

- `pCallback` is a pointer to a VkDebugReportCallbackEXT handle in which the created object is returned.

Valid Usage (Implicit)

- `instance` must be a valid VkInstance handle

- `pCreateInfo` must be a valid pointer to a valid VkDebugReportCallbackCreateInfoEXT structure

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `pCallback` must be a valid pointer to a VkDebugReportCallbackEXT handle

Return Codes

Success

  - `VK_SUCCESS`

Failure

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

The definition of VkDebugReportCallbackCreateInfoEXT is:

    typedef struct VkDebugReportCallbackCreateInfoEXT {
        VkStructureType                 sType;
        const void*                     pNext;
        VkDebugReportFlagsEXT           flags;
        PFN_vkDebugReportCallbackEXT    pfnCallback;
        void*                           pUserData;
    } VkDebugReportCallbackCreateInfoEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkDebugReportFlagBitsEXT specifying which event(s) will cause this callback to be called.

- `pfnCallback` is the application callback function to call.

- `pUserData` is user data to be passed to the callback.

For each `VkDebugReportCallbackEXT` that is created the `VkDebugReportCallbackCreateInfoEXT`::`flags` determine when that `VkDebugReportCallbackCreateInfoEXT`::`pfnCallback` is called. When an event happens, the implementation will do a bitwise AND of the event’s VkDebugReportFlagBitsEXT flags to each `VkDebugReportCallbackEXT` object’s flags. For each non-zero result the corresponding callback will be called. The callback will come directly from the component that detected the event, unless some other layer intercepts the calls for its own purposes (filter them in a different way, log to a system error log, etc.).

An application may receive multiple callbacks if multiple `VkDebugReportCallbackEXT` objects were created. A callback will always be executed in the same thread as the originating Vulkan call.

A callback may be called from multiple threads simultaneously (if the application is making Vulkan calls from multiple threads).

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DEBUG_REPORT_CALLBACK_CREATE_INFO_EXT`

- `flags` must be a valid combination of VkDebugReportFlagBitsEXT values

- `pfnCallback` must be a valid PFN_vkDebugReportCallbackEXT value

Bits which can be set in VkDebugReportCallbackCreateInfoEXT::`flags`, specifying events which cause a debug report, are:

    typedef enum VkDebugReportFlagBitsEXT {
        VK_DEBUG_REPORT_INFORMATION_BIT_EXT = 0x00000001,
        VK_DEBUG_REPORT_WARNING_BIT_EXT = 0x00000002,
        VK_DEBUG_REPORT_PERFORMANCE_WARNING_BIT_EXT = 0x00000004,
        VK_DEBUG_REPORT_ERROR_BIT_EXT = 0x00000008,
        VK_DEBUG_REPORT_DEBUG_BIT_EXT = 0x00000010,
        VK_DEBUG_REPORT_FLAG_BITS_MAX_ENUM_EXT = 0x7FFFFFFF
    } VkDebugReportFlagBitsEXT;

- `VK_DEBUG_REPORT_ERROR_BIT_EXT` specifies that the application has violated a valid usage condition of the specification.

- `VK_DEBUG_REPORT_WARNING_BIT_EXT` specifies use of Vulkan that may expose an app bug. Such cases may not be immediately harmful, such as a fragment shader outputting to a location with no attachment. Other cases may point to behavior that is almost certainly bad when unintended such as using an image whose memory has not been filled. In general if you see a warning but you know that the behavior is intended/desired, then simply ignore the warning.

- `VK_DEBUG_REPORT_PERFORMANCE_WARNING_BIT_EXT` specifies a potentially non-optimal use of Vulkan, e.g. using vkCmdClearColorImage when setting VkAttachmentDescription::`loadOp` to `VK_ATTACHMENT_LOAD_OP_CLEAR` would have worked.

- `VK_DEBUG_REPORT_INFORMATION_BIT_EXT` specifies an informational message such as resource details that may be handy when debugging an application.

- `VK_DEBUG_REPORT_DEBUG_BIT_EXT` specifies diagnostic information from the implementation and layers.

    typedef VkFlags VkDebugReportFlagsEXT;

`VkDebugReportFlagsEXT` is a bitmask type for setting a mask of zero or more VkDebugReportFlagBitsEXT.

The prototype for the VkDebugReportCallbackCreateInfoEXT::`pfnCallback` function implemented by the application is:

    typedef VkBool32 (VKAPI_PTR *PFN_vkDebugReportCallbackEXT)(
        VkDebugReportFlagsEXT                       flags,
        VkDebugReportObjectTypeEXT                  objectType,
        uint64_t                                    object,
        size_t                                      location,
        int32_t                                     messageCode,
        const char*                                 pLayerPrefix,
        const char*                                 pMessage,
        void*                                       pUserData);

- `flags` specifies the VkDebugReportFlagBitsEXT that triggered this callback.

- `objectType` is a VkDebugReportObjectTypeEXT value specifying the type of object being used or created at the time the event was triggered.

- `object` is the object where the issue was detected. If `objectType` is `VK_DEBUG_REPORT_OBJECT_TYPE_UNKNOWN_EXT`, `object` is undefined.

- `location` is a component (layer, driver, loader) defined value specifying the location of the trigger. This is an optional value.

- `messageCode` is a layer-defined value indicating what test triggered this callback.

- `pLayerPrefix` is a null-terminated string that is an abbreviation of the name of the component making the callback. `pLayerPrefix` is only valid for the duration of the callback.

- `pMessage` is a null-terminated string detailing the trigger conditions. `pMessage` is only valid for the duration of the callback.

- `pUserData` is the user data given when the VkDebugReportCallbackEXT was created.

The callback must not call `vkDestroyDebugReportCallbackEXT`.

The callback returns a `VkBool32`, which is interpreted in a layer-specified manner. The application should always return `VK_FALSE`. The `VK_TRUE` value is reserved for use in layer development.

`object` must be a Vulkan object or VK_NULL_HANDLE. If `objectType` is not `VK_DEBUG_REPORT_OBJECT_TYPE_UNKNOWN_EXT` and `object` is not VK_NULL_HANDLE, `object` must be a Vulkan object of the corresponding type associated with `objectType` as defined in VkDebugReportObjectTypeEXT and Vulkan Handle Relationship.

Possible values passed to the `objectType` parameter of the callback function specified by VkDebugReportCallbackCreateInfoEXT::`pfnCallback`, specifying the type of object handle being reported, are:

    typedef enum VkDebugReportObjectTypeEXT {
        VK_DEBUG_REPORT_OBJECT_TYPE_UNKNOWN_EXT = 0,
        VK_DEBUG_REPORT_OBJECT_TYPE_INSTANCE_EXT = 1,
        VK_DEBUG_REPORT_OBJECT_TYPE_PHYSICAL_DEVICE_EXT = 2,
        VK_DEBUG_REPORT_OBJECT_TYPE_DEVICE_EXT = 3,
        VK_DEBUG_REPORT_OBJECT_TYPE_QUEUE_EXT = 4,
        VK_DEBUG_REPORT_OBJECT_TYPE_SEMAPHORE_EXT = 5,
        VK_DEBUG_REPORT_OBJECT_TYPE_COMMAND_BUFFER_EXT = 6,
        VK_DEBUG_REPORT_OBJECT_TYPE_FENCE_EXT = 7,
        VK_DEBUG_REPORT_OBJECT_TYPE_DEVICE_MEMORY_EXT = 8,
        VK_DEBUG_REPORT_OBJECT_TYPE_BUFFER_EXT = 9,
        VK_DEBUG_REPORT_OBJECT_TYPE_IMAGE_EXT = 10,
        VK_DEBUG_REPORT_OBJECT_TYPE_EVENT_EXT = 11,
        VK_DEBUG_REPORT_OBJECT_TYPE_QUERY_POOL_EXT = 12,
        VK_DEBUG_REPORT_OBJECT_TYPE_BUFFER_VIEW_EXT = 13,
        VK_DEBUG_REPORT_OBJECT_TYPE_IMAGE_VIEW_EXT = 14,
        VK_DEBUG_REPORT_OBJECT_TYPE_SHADER_MODULE_EXT = 15,
        VK_DEBUG_REPORT_OBJECT_TYPE_PIPELINE_CACHE_EXT = 16,
        VK_DEBUG_REPORT_OBJECT_TYPE_PIPELINE_LAYOUT_EXT = 17,
        VK_DEBUG_REPORT_OBJECT_TYPE_RENDER_PASS_EXT = 18,
        VK_DEBUG_REPORT_OBJECT_TYPE_PIPELINE_EXT = 19,
        VK_DEBUG_REPORT_OBJECT_TYPE_DESCRIPTOR_SET_LAYOUT_EXT = 20,
        VK_DEBUG_REPORT_OBJECT_TYPE_SAMPLER_EXT = 21,
        VK_DEBUG_REPORT_OBJECT_TYPE_DESCRIPTOR_POOL_EXT = 22,
        VK_DEBUG_REPORT_OBJECT_TYPE_DESCRIPTOR_SET_EXT = 23,
        VK_DEBUG_REPORT_OBJECT_TYPE_FRAMEBUFFER_EXT = 24,
        VK_DEBUG_REPORT_OBJECT_TYPE_COMMAND_POOL_EXT = 25,
        VK_DEBUG_REPORT_OBJECT_TYPE_SURFACE_KHR_EXT = 26,
        VK_DEBUG_REPORT_OBJECT_TYPE_SWAPCHAIN_KHR_EXT = 27,
        VK_DEBUG_REPORT_OBJECT_TYPE_DEBUG_REPORT_CALLBACK_EXT_EXT = 28,
        VK_DEBUG_REPORT_OBJECT_TYPE_DISPLAY_KHR_EXT = 29,
        VK_DEBUG_REPORT_OBJECT_TYPE_DISPLAY_MODE_KHR_EXT = 30,
        VK_DEBUG_REPORT_OBJECT_TYPE_VALIDATION_CACHE_EXT_EXT = 33,
        VK_DEBUG_REPORT_OBJECT_TYPE_SAMPLER_YCBCR_CONVERSION_EXT = 1000156000,
        VK_DEBUG_REPORT_OBJECT_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_EXT = 1000085000,
        VK_DEBUG_REPORT_OBJECT_TYPE_ACCELERATION_STRUCTURE_KHR_EXT = 1000165000,
        VK_DEBUG_REPORT_OBJECT_TYPE_DEBUG_REPORT_EXT = VK_DEBUG_REPORT_OBJECT_TYPE_DEBUG_REPORT_CALLBACK_EXT_EXT,
        VK_DEBUG_REPORT_OBJECT_TYPE_VALIDATION_CACHE_EXT = VK_DEBUG_REPORT_OBJECT_TYPE_VALIDATION_CACHE_EXT_EXT,
        VK_DEBUG_REPORT_OBJECT_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_KHR_EXT = VK_DEBUG_REPORT_OBJECT_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_EXT,
        VK_DEBUG_REPORT_OBJECT_TYPE_SAMPLER_YCBCR_CONVERSION_KHR_EXT = VK_DEBUG_REPORT_OBJECT_TYPE_SAMPLER_YCBCR_CONVERSION_EXT,
        VK_DEBUG_REPORT_OBJECT_TYPE_ACCELERATION_STRUCTURE_NV_EXT = VK_DEBUG_REPORT_OBJECT_TYPE_ACCELERATION_STRUCTURE_KHR_EXT,
        VK_DEBUG_REPORT_OBJECT_TYPE_MAX_ENUM_EXT = 0x7FFFFFFF
    } VkDebugReportObjectTypeEXT;

Table 74. VkDebugReportObjectTypeEXT and Vulkan Handle Relationship
VkDebugReportObjectTypeEXT | Vulkan Handle Type
--- | ---
`VK_DEBUG_REPORT_OBJECT_TYPE_UNKNOWN_EXT` | Unknown/Undefined Handle
`VK_DEBUG_REPORT_OBJECT_TYPE_INSTANCE_EXT` | VkInstance
`VK_DEBUG_REPORT_OBJECT_TYPE_PHYSICAL_DEVICE_EXT` | VkPhysicalDevice
`VK_DEBUG_REPORT_OBJECT_TYPE_DEVICE_EXT` | VkDevice
`VK_DEBUG_REPORT_OBJECT_TYPE_QUEUE_EXT` | VkQueue
`VK_DEBUG_REPORT_OBJECT_TYPE_SEMAPHORE_EXT` | VkSemaphore
`VK_DEBUG_REPORT_OBJECT_TYPE_COMMAND_BUFFER_EXT` | VkCommandBuffer
`VK_DEBUG_REPORT_OBJECT_TYPE_FENCE_EXT` | VkFence
`VK_DEBUG_REPORT_OBJECT_TYPE_DEVICE_MEMORY_EXT` | VkDeviceMemory
`VK_DEBUG_REPORT_OBJECT_TYPE_BUFFER_EXT` | VkBuffer
`VK_DEBUG_REPORT_OBJECT_TYPE_IMAGE_EXT` | VkImage
`VK_DEBUG_REPORT_OBJECT_TYPE_EVENT_EXT` | VkEvent
`VK_DEBUG_REPORT_OBJECT_TYPE_QUERY_POOL_EXT` | VkQueryPool
`VK_DEBUG_REPORT_OBJECT_TYPE_BUFFER_VIEW_EXT` | VkBufferView
`VK_DEBUG_REPORT_OBJECT_TYPE_IMAGE_VIEW_EXT` | VkImageView
`VK_DEBUG_REPORT_OBJECT_TYPE_SHADER_MODULE_EXT` | VkShaderModule
`VK_DEBUG_REPORT_OBJECT_TYPE_PIPELINE_CACHE_EXT` | VkPipelineCache
`VK_DEBUG_REPORT_OBJECT_TYPE_PIPELINE_LAYOUT_EXT` | VkPipelineLayout
`VK_DEBUG_REPORT_OBJECT_TYPE_RENDER_PASS_EXT` | VkRenderPass
`VK_DEBUG_REPORT_OBJECT_TYPE_PIPELINE_EXT` | VkPipeline
`VK_DEBUG_REPORT_OBJECT_TYPE_DESCRIPTOR_SET_LAYOUT_EXT` | VkDescriptorSetLayout
`VK_DEBUG_REPORT_OBJECT_TYPE_SAMPLER_EXT` | VkSampler
`VK_DEBUG_REPORT_OBJECT_TYPE_DESCRIPTOR_POOL_EXT` | VkDescriptorPool
`VK_DEBUG_REPORT_OBJECT_TYPE_DESCRIPTOR_SET_EXT` | VkDescriptorSet
`VK_DEBUG_REPORT_OBJECT_TYPE_FRAMEBUFFER_EXT` | VkFramebuffer
`VK_DEBUG_REPORT_OBJECT_TYPE_COMMAND_POOL_EXT` | VkCommandPool
`VK_DEBUG_REPORT_OBJECT_TYPE_SURFACE_KHR_EXT` | VkSurfaceKHR
`VK_DEBUG_REPORT_OBJECT_TYPE_SWAPCHAIN_KHR_EXT` | VkSwapchainKHR
`VK_DEBUG_REPORT_OBJECT_TYPE_DEBUG_REPORT_CALLBACK_EXT_EXT` | VkDebugReportCallbackEXT
`VK_DEBUG_REPORT_OBJECT_TYPE_DISPLAY_KHR_EXT` | VkDisplayKHR
`VK_DEBUG_REPORT_OBJECT_TYPE_DISPLAY_MODE_KHR_EXT` | VkDisplayModeKHR
`VK_DEBUG_REPORT_OBJECT_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_EXT` | VkDescriptorUpdateTemplate

| Note The primary expected use of `VK_ERROR_VALIDATION_FAILED_EXT` is for validation layer testing. It is not expected that an application would see this error code during normal use of the validation layers.

To inject its own messages into the debug stream, call:

    void vkDebugReportMessageEXT(
        VkInstance                                  instance,
        VkDebugReportFlagsEXT                       flags,
        VkDebugReportObjectTypeEXT                  objectType,
        uint64_t                                    object,
        size_t                                      location,
        int32_t                                     messageCode,
        const char*                                 pLayerPrefix,
        const char*                                 pMessage);

- `instance` is the debug stream’s VkInstance.

- `flags` specifies the VkDebugReportFlagBitsEXT classification of this event/message.

- `objectType` is a VkDebugReportObjectTypeEXT specifying the type of object being used or created at the time the event was triggered.

- `object` this is the object where the issue was detected. `object` can be VK_NULL_HANDLE if there is no object associated with the event.

- `location` is an application defined value.

- `messageCode` is an application defined value.

- `pLayerPrefix` is the abbreviation of the component making this event/message.

- `pMessage` is a null-terminated string detailing the trigger conditions.

The call will propagate through the layers and generate callback(s) as indicated by the message’s flags. The parameters are passed on to the callback in addition to the `pUserData` value that was defined at the time the callback was registered.

Valid Usage

- `object` must be a Vulkan object or VK_NULL_HANDLE

- If `objectType` is not `VK_DEBUG_REPORT_OBJECT_TYPE_UNKNOWN_EXT` and `object` is not VK_NULL_HANDLE, `object` must be a Vulkan object of the corresponding type associated with `objectType` as defined in VkDebugReportObjectTypeEXT and Vulkan Handle Relationship.

Valid Usage (Implicit)

- `instance` must be a valid VkInstance handle

- `flags` must be a valid combination of VkDebugReportFlagBitsEXT values

- `flags` must not be `0`

- `objectType` must be a valid VkDebugReportObjectTypeEXT value

- `pLayerPrefix` must be a null-terminated UTF-8 string

- `pMessage` must be a null-terminated UTF-8 string

To destroy a `VkDebugReportCallbackEXT` object, call:

    void vkDestroyDebugReportCallbackEXT(
        VkInstance                                  instance,
        VkDebugReportCallbackEXT                    callback,
        const VkAllocationCallbacks*                pAllocator);

- `instance` the instance where the callback was created.

- `callback` the VkDebugReportCallbackEXT object to destroy. `callback` is an externally synchronized object and must not be used on more than one thread at a time. This means that `vkDestroyDebugReportCallbackEXT` must not be called when a callback is active.

- `pAllocator` controls host memory allocation as described in the Memory Allocation chapter.

Valid Usage

- If `VkAllocationCallbacks` were provided when `callback` was created, a compatible set of callbacks must be provided here

- If no `VkAllocationCallbacks` were provided when `callback` was created, `pAllocator` must be `NULL`

Valid Usage (Implicit)

- `instance` must be a valid VkInstance handle

- `callback` must be a valid VkDebugReportCallbackEXT handle

- If `pAllocator` is not `NULL`, `pAllocator` must be a valid pointer to a valid VkAllocationCallbacks structure

- `callback` must have been created, allocated, or retrieved from `instance`

Host Synchronization

- Host access to `callback` must be externally synchronized

### 41.4. Device Loss Debugging

#### 41.4.1. Device Diagnostic Checkpoints

Device execution progress can be tracked for the purposes of debugging a device loss by annotating the command stream with application-defined diagnostic checkpoints.

Each diagnostic checkpoint command is executed at two pipeline stages: `VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT`, and `VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT`. If the device is lost, the application can call vkGetQueueCheckpointDataNV to retrieve checkpoint data associated with both pipeline stages, indicating the range of diagnostic checkpoints that are currently in the execution pipeline on the device.

Device diagnostic checkpoints are inserted into the command stream by calling vkCmdSetCheckpointNV.

    void vkCmdSetCheckpointNV(
        VkCommandBuffer                             commandBuffer,
        const void*                                 pCheckpointMarker);

- `commandBuffer` is the command buffer that will receive the marker

- `pCheckpointMarker` is an opaque application-provided value that will be associated with the checkpoint.

Valid Usage (Implicit)

- `commandBuffer` must be a valid VkCommandBuffer handle

- `commandBuffer` must be in the recording state

- The `VkCommandPool` that `commandBuffer` was allocated from must support graphics, compute, or transfer operations

Host Synchronization

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Supported Queue Types | Pipeline Type
--- | --- | --- | ---
Primary Secondary | Both | Graphics Compute Transfer |

Note that `pCheckpointMarker` is treated as an opaque value. It does not need to be a valid pointer and will not be dereferenced by the implementation.

If the device encounters an error during execution, the implementation will return a `VK_ERROR_DEVICE_LOST` error to the application at a certain point during host execution. When this happens, the application can call vkGetQueueCheckpointDataNV to retrieve information on the most recent diagnostic checkpoints that were executed by the device.

    void vkGetQueueCheckpointDataNV(
        VkQueue                                     queue,
        uint32_t*                                   pCheckpointDataCount,
        VkCheckpointDataNV*                         pCheckpointData);

- `queue` is the VkQueue object the caller would like to retrieve checkpoint data for

- `pCheckpointDataCount` is a pointer to an integer related to the number of checkpoint markers available or queried, as described below.

- `pCheckpointData` is either `NULL` or a pointer to an array of `VkCheckpointDataNV` structures.

If `pCheckpointData` is `NULL`, then the number of checkpoint markers available is returned in `pCheckpointDataCount`.

Otherwise, `pCheckpointDataCount` must point to a variable set by the user to the number of elements in the `pCheckpointData` array, and on return the variable is overwritten with the number of structures actually written to `pCheckpointData`.

If `pCheckpointDataCount` is less than the number of checkpoint markers available, at most `pCheckpointDataCount` structures will be written.

Valid Usage

- The device that `queue` belongs to must be in the lost state

Valid Usage (Implicit)

- `queue` must be a valid VkQueue handle

- `pCheckpointDataCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pCheckpointDataCount` is not `0`, and `pCheckpointData` is not `NULL`, `pCheckpointData` must be a valid pointer to an array of `pCheckpointDataCount` VkCheckpointDataNV structures

The VkCheckpointDataNV structure is defined as:

    typedef struct VkCheckpointDataNV {
        VkStructureType            sType;
        void*                      pNext;
        VkPipelineStageFlagBits    stage;
        void*                      pCheckpointMarker;
    } VkCheckpointDataNV;

- `sType` is the type of this structure

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `stage` indicates which pipeline stage the checkpoint marker data refers to.

- `pCheckpointMarker` contains the value of the last checkpoint marker executed in the stage that `stage` refers to.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_CHECKPOINT_DATA_NV`

- `pNext` must be `NULL`

Note that the stages at which a checkpoint marker can be executed are implementation-defined and can be queried by calling vkGetPhysicalDeviceQueueFamilyProperties2.

### 41.5. Active Tooling Information

Information about tools providing debugging, profiling, or similar services, active for a given physical device, can be obtained by calling:

    VkResult vkGetPhysicalDeviceToolPropertiesEXT(
        VkPhysicalDevice                            physicalDevice,
        uint32_t*                                   pToolCount,
        VkPhysicalDeviceToolPropertiesEXT*          pToolProperties);

- `physicalDevice` is the handle to the physical device to query for active tools.

- `pToolCount` is a pointer to an integer describing the number of tools active on `physicalDevice`.

- `pToolProperties` is either `NULL` or a pointer to an array of VkPhysicalDeviceToolPropertiesEXT structures.

If `pToolProperties` is `NULL`, then the number of tools currently active on `physicalDevice` is returned in `pToolCount`. Otherwise, `pToolCount` must point to a variable set by the user to the number of elements in the `pToolProperties` array, and on return the variable is overwritten with the number of structures actually written to `pToolProperties`. If `pToolCount` is less than the number of currently active tools, at most `pToolCount` structures will be written.

The count and properties of active tools may change in response to events outside the scope of the specification. An application should assume these properties might change at any given time.

Valid Usage (Implicit)

- `physicalDevice` must be a valid VkPhysicalDevice handle

- `pToolCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pToolCount` is not `0`, and `pToolProperties` is not `NULL`, `pToolProperties` must be a valid pointer to an array of `pToolCount` VkPhysicalDeviceToolPropertiesEXT structures

Return Codes

Success

  - `VK_SUCCESS`

  - `VK_INCOMPLETE`

The VkPhysicalDeviceToolPropertiesEXT structure is defined as:

    typedef struct VkPhysicalDeviceToolPropertiesEXT {
        VkStructureType          sType;
        void*                    pNext;
        char                     name[VK_MAX_EXTENSION_NAME_SIZE];
        char                     version[VK_MAX_EXTENSION_NAME_SIZE];
        VkToolPurposeFlagsEXT    purposes;
        char                     description[VK_MAX_DESCRIPTION_SIZE];
        char                     layer[VK_MAX_EXTENSION_NAME_SIZE];
    } VkPhysicalDeviceToolPropertiesEXT;

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `name` is a null-terminated UTF-8 string containing the name of the tool.

- `version` is a null-terminated UTF-8 string containing the version of the tool.

- `purposes` is a bitmask of VkToolPurposeFlagBitsEXT which is populated with purposes supported by the tool.

- `description` is a null-terminated UTF-8 string containing a description of the tool.

- `layer` is a null-terminated UTF-8 string that contains the name of the layer implementing the tool, if the tool is implemented in a layer - otherwise it may be an empty string.

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TOOL_PROPERTIES_EXT`

- `pNext` must be `NULL`

Bits which can be set in VkDeviceQueueCreateInfo::`purposes` specifying the purposes of an active tool are:

    typedef enum VkToolPurposeFlagBitsEXT {
        VK_TOOL_PURPOSE_VALIDATION_BIT_EXT = 0x00000001,
        VK_TOOL_PURPOSE_PROFILING_BIT_EXT = 0x00000002,
        VK_TOOL_PURPOSE_TRACING_BIT_EXT = 0x00000004,
        VK_TOOL_PURPOSE_ADDITIONAL_FEATURES_BIT_EXT = 0x00000008,
        VK_TOOL_PURPOSE_MODIFYING_FEATURES_BIT_EXT = 0x00000010,
        VK_TOOL_PURPOSE_DEBUG_REPORTING_BIT_EXT = 0x00000020,
        VK_TOOL_PURPOSE_DEBUG_MARKERS_BIT_EXT = 0x00000040,
        VK_TOOL_PURPOSE_FLAG_BITS_MAX_ENUM_EXT = 0x7FFFFFFF
    } VkToolPurposeFlagBitsEXT;

- `VK_TOOL_PURPOSE_VALIDATION_BIT_EXT` specifies that the tool provides validation of API usage.

- `VK_TOOL_PURPOSE_PROFILING_BIT_EXT` specifies that the tool provides profiling of API usage.

- `VK_TOOL_PURPOSE_TRACING_BIT_EXT` specifies that the tool is capturing data about the application’s API usage, including anything from simple logging to capturing data for later replay.

- `VK_TOOL_PURPOSE_ADDITIONAL_FEATURES_BIT_EXT` specifies that the tool provides additional API features/extensions on top of the underlying implementation.

- `VK_TOOL_PURPOSE_MODIFYING_FEATURES_BIT_EXT` specifies that the tool modifies the API features/limits/extensions presented to the application.

- `VK_TOOL_PURPOSE_DEBUG_REPORTING_BIT_EXT` specifies that the tool reports additional information to the application via callbacks specified by vkCreateDebugReportCallbackEXT or vkCreateDebugUtilsMessengerEXT

- `VK_TOOL_PURPOSE_DEBUG_MARKERS_BIT_EXT` specifies that the tool consumes debug markers or object debug annotation, queue labels, or command buffer labels

    typedef VkFlags VkToolPurposeFlagsEXT;

VkToolPurposeFlagsEXT is a bitmask type for setting a mask of zero or more VkToolPurposeFlagBitsEXT.

## Appendix A: Vulkan Environment for SPIR-V

Shaders for Vulkan are defined by the Khronos SPIR-V Specification as well as the Khronos SPIR-V Extended Instructions for GLSL Specification. This appendix defines additional SPIR-V requirements applying to Vulkan shaders.

### Versions and Formats

A Vulkan 1.2 implementation must support the 1.0, 1.1, 1.2, 1.3, 1.4, and 1.5 versions of SPIR-V and the 1.0 version of the SPIR-V Extended Instructions for GLSL.

A SPIR-V module passed into vkCreateShaderModule is interpreted as a series of 32-bit words in host endianness, with literal strings packed as described in section 2.2 of the SPIR-V Specification. The first few words of the SPIR-V module must be a magic number and a SPIR-V version number, as described in section 2.3 of the SPIR-V Specification.

### Capabilities

The SPIR-V capabilities listed below must be supported if the corresponding feature or extension is enabled, or if no features or extensions are listed for that capability. Extensions are only listed when there is not also a feature bit associated with that capability.

Table 75. List of SPIR-V Capabilities and enabling features or extensions
SPIR-V `OpCapability` | Vulkan feature or extension name
--- | ---
`Matrix` |
`Shader` |
`InputAttachment` |
`Sampled1D` |
`Image1D` |
`SampledBuffer` |
`ImageBuffer` |
`ImageQuery` |
`DerivativeControl` |
`Geometry` | `geometryShader`
`Tessellation` | `tessellationShader`
`Float64` | `shaderFloat64`
`Int64` | `shaderInt64`
`Int64Atomics` | shaderBufferInt64Atomics, shaderSharedInt64Atomics
`Int16` | `shaderInt16`
`TessellationPointSize` | `shaderTessellationAndGeometryPointSize`
`GeometryPointSize` | `shaderTessellationAndGeometryPointSize`
`ImageGatherExtended` | `shaderImageGatherExtended`
`StorageImageMultisample` | `shaderStorageImageMultisample`
`UniformBufferArrayDynamicIndexing` | `shaderUniformBufferArrayDynamicIndexing`
`SampledImageArrayDynamicIndexing` | `shaderSampledImageArrayDynamicIndexing`
`StorageBufferArrayDynamicIndexing` | `shaderStorageBufferArrayDynamicIndexing`
`StorageImageArrayDynamicIndexing` | `shaderStorageImageArrayDynamicIndexing`
`ClipDistance` | `shaderClipDistance`
`CullDistance` | `shaderCullDistance`
`ImageCubeArray` | `imageCubeArray`
`SampleRateShading` | `sampleRateShading`
`SparseResidency` | `shaderResourceResidency`
`MinLod` | `shaderResourceMinLod`
`SampledCubeArray` | `imageCubeArray`
`ImageMSArray` | `shaderStorageImageMultisample`
`StorageImageExtendedFormats` |
`InterpolationFunction` | `sampleRateShading`
`StorageImageReadWithoutFormat` | `shaderStorageImageReadWithoutFormat`
`StorageImageWriteWithoutFormat` | `shaderStorageImageWriteWithoutFormat`
`MultiViewport` | `multiViewport`
`DrawParameters` | `shaderDrawParameters` , `VK_KHR_shader_draw_parameters`
`MultiView` |
`DeviceGroup` |
`VariablePointersStorageBuffer` | `variablePointersStorageBuffer`
`VariablePointers` | `variablePointers`
`ShaderClockKHR` | `VK_KHR_shader_clock`
`StencilExportEXT` | `VK_EXT_shader_stencil_export`
`SubgroupBallotKHR` | `VK_EXT_shader_subgroup_ballot`
`SubgroupVoteKHR` | `VK_EXT_shader_subgroup_vote`
`ImageReadWriteLodAMD` | `VK_AMD_shader_image_load_store_lod`
`ImageGatherBiasLodAMD` | `VK_AMD_texture_gather_bias_lod`
`FragmentMaskAMD` | `VK_AMD_shader_fragment_mask`
`SampleMaskOverrideCoverageNV` | `VK_NV_sample_mask_override_coverage`
`GeometryShaderPassthroughNV` | `VK_NV_geometry_shader_passthrough`
`ShaderViewportIndex` | shaderOutputViewportIndex
`ShaderLayer` | shaderOutputLayer
`ShaderViewportIndexLayerEXT` | `VK_EXT_shader_viewport_index_layer`
`ShaderViewportIndexLayerNV` | `VK_NV_viewport_array2`
`ShaderViewportMaskNV` | `VK_NV_viewport_array2`
`PerViewAttributesNV` | `VK_NVX_multiview_per_view_attributes`
`StorageBuffer16BitAccess` | `StorageBuffer16BitAccess`
`UniformAndStorageBuffer16BitAccess` | `UniformAndStorageBuffer16BitAccess`
`StoragePushConstant16` | `storagePushConstant16`
`StorageInputOutput16` | `storageInputOutput16`
`GroupNonUniform` | `VK_SUBGROUP_FEATURE_BASIC_BIT`
`GroupNonUniformVote` | `VK_SUBGROUP_FEATURE_VOTE_BIT`
`GroupNonUniformArithmetic` | `VK_SUBGROUP_FEATURE_ARITHMETIC_BIT`
`GroupNonUniformBallot` | `VK_SUBGROUP_FEATURE_BALLOT_BIT`
`GroupNonUniformShuffle` | `VK_SUBGROUP_FEATURE_SHUFFLE_BIT`
`GroupNonUniformShuffleRelative` | `VK_SUBGROUP_FEATURE_SHUFFLE_RELATIVE_BIT`
`GroupNonUniformClustered` | `VK_SUBGROUP_FEATURE_CLUSTERED_BIT`
`GroupNonUniformQuad` | `VK_SUBGROUP_FEATURE_QUAD_BIT`
`GroupNonUniformPartitionedNV` | `VK_SUBGROUP_FEATURE_PARTITIONED_BIT_NV`
`SampleMaskPostDepthCoverage` | `VK_EXT_post_depth_coverage`
`ShaderNonUniform` |
`ShaderNonUniformEXT` | `VK_EXT_descriptor_indexing`
`RuntimeDescriptorArray` | `runtimeDescriptorArray`
`InputAttachmentArrayDynamicIndexing` | `shaderInputAttachmentArrayDynamicIndexing`
`UniformTexelBufferArrayDynamicIndexing` | `shaderUniformTexelBufferArrayDynamicIndexing`
`StorageTexelBufferArrayDynamicIndexing` | `shaderStorageTexelBufferArrayDynamicIndexing`
`UniformBufferArrayNonUniformIndexing` | `shaderUniformBufferArrayNonUniformIndexing`
`SampledImageArrayNonUniformIndexing` | `shaderSampledImageArrayNonUniformIndexing`
`StorageBufferArrayNonUniformIndexing` | `shaderStorageBufferArrayNonUniformIndexing`
`StorageImageArrayNonUniformIndexing` | `shaderStorageImageArrayNonUniformIndexing`
`InputAttachmentArrayNonUniformIndexing` | `shaderInputAttachmentArrayNonUniformIndexing`
`UniformTexelBufferArrayNonUniformIndexing` | `shaderUniformTexelBufferArrayNonUniformIndexing`
`StorageTexelBufferArrayNonUniformIndexing` | `shaderStorageTexelBufferArrayNonUniformIndexing`
`Float16` | `shaderFloat16` , or `VK_AMD_gpu_shader_half_float`
`Int8` | `shaderInt8`
`StorageBuffer8BitAccess` | `StorageBuffer8BitAccess`
`UniformAndStorageBuffer8BitAccess` | `UniformAndStorageBuffer8BitAccess`
`StoragePushConstant8` | `StoragePushConstant8`
`VulkanMemoryModel` | `vulkanMemoryModel`
`VulkanMemoryModelDeviceScope` | `vulkanMemoryModelDeviceScope`
`DenormPreserve` | `shaderDenormPreserveFloat16`, `shaderDenormPreserveFloat32`, `shaderDenormPreserveFloat64`
`DenormFlushToZero` | `shaderDenormFlushToZeroFloat16`, `shaderDenormFlushToZeroFloat32`, `shaderDenormFlushToZeroFloat64`
`SignedZeroInfNanPreserve` | `shaderSignedZeroInfNanPreserveFloat16`, `shaderSignedZeroInfNanPreserveFloat32`, `shaderSignedZeroInfNanPreserveFloat64`
`RoundingModeRTE` | `shaderRoundingModeRTEFloat16`, `shaderRoundingModeRTEFloat32`, `shaderRoundingModeRTEFloat64`
`RoundingModeRTZ` | `shaderRoundingModeRTZFloat16`, `shaderRoundingModeRTZFloat32`, `shaderRoundingModeRTZFloat64`
`ComputeDerivativeGroupQuadsNV` | `computeDerivativeGroupQuads`
`ComputeDerivativeGroupLinearNV` | `computeDerivativeGroupLinear`
`FragmentBarycentricNV` | `fragmentShaderBarycentric`
`ImageFootprintNV` | `imageFootprint`
`ShadingRateImageNV` | `shadingRateImage`
`MeshShadingNV` | `VK_NV_mesh_shader`
`RayTracingProvisionalKHR` | rayTracing
`RayQueryProvisionalKHR` | rayQuery
`RayTraversalPrimitiveCullingProvisionalKHR` | rayTracingPrimitiveCulling
`RayTracingNV` | `VK_NV_ray_tracing`
`TransformFeedback` | `transformFeedback`
`GeometryStreams` | `geometryStreams`
`FragmentDensityEXT` | `fragmentDensityMap`
`PhysicalStorageBufferAddresses` | bufferDeviceAddress , `VkPhysicalDeviceBufferDeviceAddressFeaturesEXT`::`bufferDeviceAddress`
`CooperativeMatrixNV` | `cooperativeMatrix`
`ShaderIntegerFunctions2INTEL` | `shaderIntegerFunctions2`
`ShaderSMBuiltinsNV` | `shaderSMBuiltins`
`FragmentShaderSampleInterlockEXT` | `fragmentShaderSampleInterlock`
`FragmentShaderPixelInterlockEXT` | `fragmentShaderPixelInterlock`
`FragmentShaderShadingRateInterlockEXT` | `fragmentShaderShadingRateInterlock`, shadingRateImage
`DemoteToHelperInvocationEXT` | `shaderDemoteToHelperInvocation`

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_KHR_variable_pointers` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_AMD_shader_explicit_vertex_parameter` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_AMD_gcn_shader` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_AMD_gpu_shader_half_float` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_AMD_gpu_shader_int16` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_AMD_shader_ballot` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_AMD_shader_fragment_mask` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_AMD_shader_image_load_store_lod` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_AMD_shader_trinary_minmax` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_AMD_texture_gather_bias_lod` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_KHR_shader_draw_parameters` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_KHR_8bit_storage` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_KHR_16bit_storage` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_KHR_shader_clock` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_KHR_float_controls` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_KHR_storage_buffer_storage_class` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_KHR_post_depth_coverage` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_EXT_shader_stencil_export` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_KHR_shader_ballot` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_KHR_subgroup_vote` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_NV_sample_mask_override_coverage` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_NV_geometry_shader_passthrough` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_NV_mesh_shader` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_NV_viewport_array2` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_NV_shader_subgroup_partitioned` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_EXT_shader_viewport_index_layer` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_NVX_multiview_per_view_attributes` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_EXT_descriptor_indexing` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_KHR_vulkan_memory_model` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_NV_compute_shader_derivatives` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_NV_fragment_shader_barycentric` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_NV_shader_image_footprint` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_NV_shading_rate` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_KHR_ray_tracing` or `SPV_NV_ray_tracing` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_KHR_ray_query` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_GOOGLE_hlsl_functionality1` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_GOOGLE_user_type` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_GOOGLE_decorate_string` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_EXT_fragment_invocation_density` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_KHR_physical_storage_buffer` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_EXT_physical_storage_buffer` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_NV_cooperative_matrix` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_NV_shader_sm_builtins` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_EXT_fragment_shader_interlock` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_EXT_demote_to_helper_invocation` SPIR-V extension.

The application can pass a SPIR-V module to vkCreateShaderModule that uses the `SPV_KHR_non_semantic_info` SPIR-V extension.

The application must not pass a SPIR-V module containing any of the following to vkCreateShaderModule:

- any `OpCapability` not listed above,

- an unsupported capability, or

- a capability which corresponds to a Vulkan feature or extension which has not been enabled.

### Validation Rules within a Module

A SPIR-V module passed to vkCreateShaderModule must conform to the following rules:

- Every entry point must have no return value and accept no arguments.

- Recursion: The static function-call graph for an entry point must not contain cycles.

- The Logical or PhysicalStorageBuffer64 addressing model must be selected.

- Scope for execution must be limited to:

  - Workgroup

    - The Workgroup scope must only be used in the task, mesh, tessellation control, and compute execution models.

  - Subgroup

- Scope for memory must be limited to:

  - Device

    - If `vulkanMemoryModel` is enabled and `vulkanMemoryModelDeviceScope` is not enabled, Device scope must not be used.

    - If `vulkanMemoryModel` is not enabled, Device scope only extends to the queue family, not the whole device.

  - QueueFamily

    - If `vulkanMemoryModel` is not enabled, QueueFamily must not be used.

  - Workgroup

    - The WorkGroup scope must only be used in the task, mesh, and compute execution model(s).

  - Subgroup

  - Invocation

- Scope for Non Uniform Group Operations must be limited to:

  - Subgroup

- Storage Class must be limited to:

  - UniformConstant

  - Input

  - Uniform

  - Output

    - The Output storage class must not be used in the RayGenerationKHR, IntersectionKHR, AnyHitKHR, ClosestHitKHR, MissKHR, or CallableKHR execution models.

  - Workgroup

    - The Workgroup storage class must only be used in the task, mesh, and compute execution model(s).

  - Private

  - Function

  - PushConstant

  - Image

  - StorageBuffer

  - RayPayloadKHR

  - IncomingRayPayloadKHR

  - HitAttributeKHR

  - CallableDataKHR

  - IncomingCallableDataKHR

  - ShaderRecordBufferKHR

  - PhysicalStorageBuffer

- Memory semantics must obey the following rules:

  - Acquire must not be used with `OpAtomicStore`.

  - Release must not be used with `OpAtomicLoad`.

  - AcquireRelease must not be used with `OpAtomicStore` or `OpAtomicLoad`.

  - Sequentially consistent atomics and barriers are not supported and SequentiallyConsistent is treated as AcquireRelease. SequentiallyConsistent should not be used.

  - `OpMemoryBarrier` must use one of Acquire, Release, AcquireRelease, or SequentiallyConsistent and must include at least one storage class.

  - If the semantics for `OpControlBarrier` includes one of Acquire, Release, AcquireRelease, or SequentiallyConsistent, then it must include at least one storage class.

  - SubgroupMemory, CrossWorkgroupMemory, and AtomicCounterMemory are ignored.

- Any `OpVariable` with an `Initializer` operand must have one of the following as its Storage Class operand:

  - Output

  - Private

  - Function

- Scope for `OpReadClockKHR` must be limited to:

  - `Subgroup`

    - if `shaderSubgroupClock` is not enabled, the `Subgroup` scope must not be used.

  - `Device`

    - if `shaderDeviceClock` is not enabled, the `Device` scope must not be used.

- The `OriginLowerLeft` execution mode must not be used; fragment entry points must declare `OriginUpperLeft`.

- The `PixelCenterInteger` execution mode must not be used. Pixels are always centered at half-integer coordinates.

- Any variable in the `UniformConstant` storage class must be typed as either:

  - `OpTypeImage`

  - `OpTypeSampler`

  - `OpTypeSampledImage`

  - `OpTypeAccelerationStructureKHR`,

  - An array of one of these types.

- Images and Samplers

  - `OpTypeImage` must declare a scalar 32-bit float or 32-bit integer type for the “Sampled Type”. (`RelaxedPrecision` can be applied to a sampling instruction and to the variable holding the result of a sampling instruction.)

  - If the `Sampled` `Type` of an `OpTypeImage` declaration does not match the numeric format of the corresponding resource in type, as shown in the SPIR-V Sampled Type column of the Interpretation of Numeric Format table, the values obtained by reading or sampling from the image are undefined.

  - If the signedness of any read or sample operation does not match the signedness of the corresponding resource then the values obtained are undefined.

  - `OpTypeImage` must have a “Sampled” operand of 1 (sampled image) or 2 (storage image).

  - If shaderStorageImageReadWithoutFormat is not enabled and an `OpTypeImage` has “Image Format” operand of `Unknown`, any variables created with the given type must be decorated with `NonReadable`.

  - If shaderStorageImageWriteWithoutFormat is not enabled and an `OpTypeImage` has “Image Format” operand of `Unknown`, any variables created with the given type must be decorated with `NonWritable`.

  - `OpImageQuerySizeLod`, and `OpImageQueryLevels` must only consume an “Image” operand whose type has its “Sampled” operand set to 1.

  - The (u,v) coordinates used for a `SubpassData` must be the <id> of a constant vector (0,0), or if a layer coordinate is used, must be a vector that was formed with constant 0 for the u and v components.

  - The “Depth” operand of `OpTypeImage` is ignored.

  - Objects of types `OpTypeImage`, `OpTypeSampler`, `OpTypeSampledImage`, and arrays of these types must not be stored to or modified.

- Any image operation must use at most one of the `Offset`, `ConstOffset`, and `ConstOffsets` image operands.

- Image operand `Offset` must only be used with `OpImage`*`Gather` instructions.

- The “Component” operand of `OpImageGather`, and `OpImageSparseGather` must be the <id> of a constant instruction.

- Acceleration Structures

  - Objects of types `OpTypeAccelerationStructureKHR` and arrays of this type must not be stored to or modified.

- The value of the “Hit Kind” operand of `OpReportIntersectionKHR` must be in the range [0,127].

- Structure types must not contain opaque types.

- Decorations

  - Any `BuiltIn` decoration not listed in Built-In Variables must not be used.

  - Any `BuiltIn` decoration that corresponds only to Vulkan features or extensions that have not been enabled must not be used.

  - The `GLSLShared` and `GLSLPacked` decorations must not be used.

  - The `Flat`, `NoPerspective`, `Sample`, and `Centroid` decorations must not be used on variables with storage class other than `Input` or on variables used in the interface of non-fragment shader entry points.

  - The `Patch` decoration must not be used on variables in the interface of a vertex, geometry, or fragment shader stage’s entry point.

  - The `ViewportRelativeNV` decoration must only be used on a variable decorated with `Layer` in the vertex, tessellation evaluation, or geometry shader stages.

  - The `ViewportRelativeNV` decoration must not be used unless a variable decorated with one of `ViewportIndex` or `ViewportMaskNV` is also statically used by the same `OpEntryPoint`.

  - The `ViewportMaskNV` and `ViewportIndex` decorations must not both be statically used by one or more `OpEntryPoint`’s that form the vertex processing stages of a graphics pipeline.

  - Only the round-to-nearest-even and the round-towards-zero rounding modes can be used for the `FPRoundingMode` decoration.

  - The `FPRoundingMode` decoration can only be used for the floating-point conversion instructions as described in the `SPV_KHR_16bit_storage` SPIR-V extension.

  - `DescriptorSet` and `Binding` decorations must obey the constraints on storage class, type, and descriptor type described in DescriptorSet and Binding Assignment

  - Variables decorated with `Invariant` and variables with structure types that have any members decorated with `Invariant` must be in the `Output` or `Input` storage class. `Invariant` used on an `Input` storage class variable or structure member has no effect.

- `OpTypeRuntimeArray` must only be used for:

  - the last member of an `OpTypeStruct` that is in the `StorageBuffer` storage class decorated as `Block`, or that is in the `PhysicalStorageBuffer` storage class decorated as `Block`, or that is in the `Uniform` storage class decorated as `BufferBlock`.

  - If the `RuntimeDescriptorArray` capability is supported, an array of variables with storage class `Uniform`, `StorageBuffer`, or `UniformConstant`, or for the outermost dimension of an array of arrays of such variables.

- Specialization constants:

  - A type T that is an array sized with a specialization constant can be, or be contained in, the type of a Variable V only if:

    - T is the (top-level) type of V, or

    - V is declared in the `Function`, `Private`, or `Workgroup` storage classes, or

    - V is an interface variable with an additional level of arrayness, as described in interface matching, in which case T is allowed to be the element type of the (top-level) type of V.

- Linkage: See Shader Interfaces for additional linking and validation rules.

- If `OpControlBarrier` is used in ray generation, intersection, any-hit, closest hit, miss, fragment, vertex, tessellation evaluation, or geometry shaders, the execution Scope must be `Subgroup`.

- Compute Shaders

  - For each compute shader entry point, either a `LocalSize` execution mode or an object decorated with the `WorkgroupSize` decoration must be specified.

  - For compute shaders using the `DerivativeGroupQuadsNV` execution mode, the first two dimensions of the local workgroup size must be a multiple of two.

  - For compute shaders using the `DerivativeGroupLinearNV` execution mode, the product of the dimensions of the local workgroup size must be a multiple of four.

- “Result Type” for Non Uniform Group Operations must be limited to 32-bit floating-point, 32-bit integer, boolean, or vectors of these types.

  - If the `Float64` capability is enabled, 64-bit floating-point and vector of 64-bit floating-point types are also permitted.

  - If the `Int8` capability is enabled and the shaderSubgroupExtendedTypes feature is `VK_TRUE`, 8-bit integer and vector of 8-bit integer types are also permitted.

  - If the `Int16` capability is enabled and the shaderSubgroupExtendedTypes feature is `VK_TRUE`, 16-bit integer and vector of 16-bit integer types are also permitted.

  - If the `Int64` capability is enabled and the shaderSubgroupExtendedTypes feature is `VK_TRUE`, 64-bit integer and vector of 64-bit integer types are also permitted.

  - If the `Float16` capability is enabled and the shaderSubgroupExtendedTypes feature is `VK_TRUE`, 16-bit floating-point and vector of 16-bit floating-point types are also permitted.

- If `OpGroupNonUniformBallotBitCount` is used, the group operation must be one of:

  - Reduce

  - InclusiveScan

  - ExclusiveScan

- If `subgroupBroadcastDynamicId` is `VK_TRUE`, and the shader module version is 1.5 or higher, the “Index” for `OpGroupNonUniformQuadBroadcast` must be dynamically uniform within the derivative group. Otherwise, “Index” must be a constant.

- If `subgroupBroadcastDynamicId` is `VK_TRUE`, and the shader module version is 1.5 or higher, the “Id” for `OpGroupNonUniformBroadcast` must be dynamically uniform within the subgroup. Otherwise, “Id” must be a constant.

- Atomic instructions must declare a scalar 32-bit integer type, or a scalar 64-bit integer type if the `Int64Atomics` capability is enabled, for the value pointed to by Pointer.

  - shaderBufferInt64Atomics must be enabled for 64-bit integer atomic operations to be supported on a Pointer with a Storage Class of StorageBuffer or Uniform.

  - shaderSharedInt64Atomics must be enabled for 64-bit integer atomic operations to be supported on a Pointer with a Storage Class of Workgroup.

- The Pointer operand of all atomic instructions must have a Storage Class limited to:

  - Uniform

  - Workgroup

  - Image

  - StorageBuffer

- If an instruction loads from or stores to a resource (including atomics and image instructions) and the resource descriptor being accessed is not dynamically uniform, then the operand corresponding to that resource (e.g. the pointer or sampled image operand) must be decorated with `NonUniform`.

- If `denormBehaviorIndependence` is `VK_SHADER_FLOAT_CONTROLS_INDEPENDENCE_32_BIT_ONLY`, then the entry point must use the same denormals execution mode for both 16-bit and 64-bit floating-point types.

- If `denormBehaviorIndependence` is `VK_SHADER_FLOAT_CONTROLS_INDEPENDENCE_NONE`, then the entry point must use the same denormals execution mode for all floating-point types.

- If `roundingModeIndependence` is `VK_SHADER_FLOAT_CONTROLS_INDEPENDENCE_32_BIT_ONLY`, then the entry point must use the same rounding execution mode for both 16-bit and 64-bit floating-point types.

- If `roundingModeIndependence` is `VK_SHADER_FLOAT_CONTROLS_INDEPENDENCE_NONE`, then the entry point must use the same rounding execution mode for all floating-point types.

- If `shaderSignedZeroInfNanPreserveFloat16` is `VK_FALSE`, then `SignedZeroInfNanPreserve` for 16-bit floating-point type must not be used.

- If `shaderSignedZeroInfNanPreserveFloat32` is `VK_FALSE`, then `SignedZeroInfNanPreserve` for 32-bit floating-point type must not be used.

- If `shaderSignedZeroInfNanPreserveFloat64` is `VK_FALSE`, then `SignedZeroInfNanPreserve` for 64-bit floating-point type must not be used.

- If `shaderDenormPreserveFloat16` is `VK_FALSE`, then `DenormPreserve` for 16-bit floating-point type must not be used.

- If `shaderDenormPreserveFloat32` is `VK_FALSE`, then `DenormPreserve` for 32-bit floating-point type must not be used.

- If `shaderDenormPreserveFloat64` is `VK_FALSE`, then `DenormPreserve` for 64-bit floating-point type must not be used.

- If `shaderDenormFlushToZeroFloat16` is `VK_FALSE`, then `DenormFlushToZero` for 16-bit floating-point type must not be used.

- If `shaderDenormFlushToZeroFloat32` is `VK_FALSE`, then `DenormFlushToZero` for 32-bit floating-point type must not be used.

- If `shaderDenormFlushToZeroFloat64` is `VK_FALSE`, then `DenormFlushToZero` for 64-bit floating-point type must not be used.

- If `shaderRoundingModeRTEFloat16` is `VK_FALSE`, then `RoundingModeRTE` for 16-bit floating-point type must not be used.

- If `shaderRoundingModeRTEFloat32` is `VK_FALSE`, then `RoundingModeRTE` for 32-bit floating-point type must not be used.

- If `shaderRoundingModeRTEFloat64` is `VK_FALSE`, then `RoundingModeRTE` for 64-bit floating-point type must not be used.

- If `shaderRoundingModeRTZFloat16` is `VK_FALSE`, then `RoundingModeRTZ` for 16-bit floating-point type must not be used.

- If `shaderRoundingModeRTZFloat32` is `VK_FALSE`, then `RoundingModeRTZ` for 32-bit floating-point type must not be used.

- If `shaderRoundingModeRTZFloat64` is `VK_FALSE`, then `RoundingModeRTZ` for 64-bit floating-point type must not be used.

- The `Offset` plus size of the type of each variable, in the output interface of the entry point being compiled, decorated with `XfbBuffer` must not be greater than `VkPhysicalDeviceTransformFeedbackPropertiesEXT`::`maxTransformFeedbackBufferDataSize`

- For any given `XfbBuffer` value, define the buffer data size to be smallest number of bytes such that, for all outputs decorated with the same `XfbBuffer` value, the size of the output interface variable plus the `Offset` is less than or equal to the buffer data size. For a given `Stream`, the sum of all the buffer data sizes for all buffers writing to that stream the must not exceed `VkPhysicalDeviceTransformFeedbackPropertiesEXT`::`maxTransformFeedbackStreamDataSize`

- Output variables or block members decorated with `Offset` that have a 64-bit type, or a composite type containing a 64-bit type, must specify an `Offset` value aligned to a 8 byte boundary

- Any output block or block member decorated with `Offset` containing a 64-bit type consumes a multiple of 8 bytes

- The size of any output block containing any member decorated with `Offset` that is a 64-bit type must be a multiple of 8

- The first member of an output block that specifies a `Offset` decoration must specify a `Offset` value that is aligned to an 8 byte boundary if that block contains any member decorated with `Offset` and is a 64-bit type

- Output variables or block members decorated with `Offset` that have a 32-bit type, or a composite type contains a 32-bit type, must specify an `Offset` value aligned to a 4 byte boundary

- Output variables, blocks or block members decorated with `Offset` must only contain base types that have components that are either 32-bit or 64-bit in size

- The Stream value to `OpEmitStreamVertex` and `OpEndStreamPrimitive` must be less than `VkPhysicalDeviceTransformFeedbackPropertiesEXT`::`maxTransformFeedbackStreams`

- If the geometry shader emits to more than one vertex stream and `VkPhysicalDeviceTransformFeedbackPropertiesEXT`::`transformFeedbackStreamsLinesTriangles` is `VK_FALSE`, then execution mode must be `OutputPoints`

- Only variables or block members in the output interface decorated with `Offset` can be captured for transform feedback, and those variables or block memebers must also be decorated with `XfbBuffer` and `XfbStride`, or inherit `XfbBuffer` and `XfbStride` decorations from a block containing them

- All variables or block members in the output interface of the entry point being compiled decorated with a specific `XfbBuffer` value must all be decorated with identical `XfbStride` values

- If any variables or block members in the output interface of the entry point being compiled are decorated with `Stream`, then all variables belonging to the same `XfbBuffer` must specify the same `Stream` value

- Output variables, blocks or block members that are not decorated with `Stream` default to vertex stream zero

- For any two variables or block members in the output interface of the entry point being compiled with the same `XfbBuffer` value, the ranges determined by the `Offset` decoration and the size of the type must not overlap

- The stream number value to `Stream` must be less than `VkPhysicalDeviceTransformFeedbackPropertiesEXT`::`maxTransformFeedbackStreams`

- The XFB Stride value to `XfbStride` must be less than or equal to `VkPhysicalDeviceTransformFeedbackPropertiesEXT`::`maxTransformFeedbackBufferDataStride`

- `RayPayloadKHR` storage class must only be used in ray generation, any-hit, closest hit or miss shaders.

- `IncomingRayPayloadKHR` storage class must only be used in closest hit, any-hit, or miss shaders.

- `HitAttributeKHR` storage class must only be used in intersection, any-hit, or closest hit shaders.

- `CallableDataKHR` storage class must only be used in ray generation, closest hit, miss, and callable shaders.

- `IncomingCallableDataKHR` storage class must only be used in callable shaders.

- The `Base` operand of `OpPtrAccessChain` must point to one of the following storage classes:

  - Workgroup, if `VariablePointers` is enabled.

  - StorageBuffer, if `VariablePointers` or `VariablePointersStorageBuffer` is enabled.

  - PhysicalStorageBuffer, if the `PhysicalStorageBuffer64` addressing model is enabled.

- If the `PhysicalStorageBuffer64` addressing model is enabled:

  - Any load or store through a physical pointer type must be aligned to a multiple of the size of the largest scalar type in the pointed-to type.

  - All instructions that support memory access operands and that use a physical pointer must include the `Aligned` operand.

  - The pointer value of a memory access instruction must be at least as aligned as specified by the `Aligned` memory access operand.

  - Any access chain instruction that accesses into a `RowMajor` matrix must only be used as the `Pointer` operand to `OpLoad` or `OpStore`.

  - `OpConvertUToPtr` and `OpConvertPtrToU` must use an integer type whose `Width` is 64.

- For `OpCooperativeMatrixLoadNV` and `OpCooperativeMatrixStoreNV` instructions, the `Pointer` and `Stride` operands must be aligned to at least the lesser of 16 bytes or the natural alignment of a row or column (depending on `ColumnMajor`) of the matrix (where the natural alignment is the number of columns/rows multiplied by the component size).

- For `OpTypeCooperativeMatrixNV`, the component type, scope, number of rows, and number of columns must match one of the matrices in any of the supported VkCooperativeMatrixPropertiesNV.

- For `OpCooperativeMatrixMulAddNV`, the `Result`, `A`, `B`, and `C` matrices must all have types that satisfy the same supported VkCooperativeMatrixPropertiesNV. That is, for one supported VkCooperativeMatrixPropertiesNV, all of the following must hold:

  - The type of `A` must have `MSize` rows and `KSize` columns and have a component type that matches `AType`.

  - The type of `B` must have `KSize` rows and `NSize` columns and have a component type that matches `BType`.

  - The type of `C` must have `MSize` rows and `NSize` columns and have a component type that matches `CType`.

  - The type of `Result` must have `MSize` rows and `NSize` columns and have a component type that matches `DType`.

  - The type of `A`, `B`, `C`, and `Result` must all have a scope of `scope`.

- `OpTypeCooperativeMatrixNV` and `OpCooperativeMatrix`* instructions must not be used in shader stages not included in VkPhysicalDeviceCooperativeMatrixPropertiesNV::`cooperativeMatrixSupportedStages`.

### Precision and Operation of SPIR-V Instructions

The following rules apply to half, single, and double-precision floating point instructions:

- Positive and negative infinities and positive and negative zeros are generated as dictated by IEEE 754, but subject to the precisions allowed in the following table.

- Dividing a non-zero by a zero results in the appropriately signed IEEE 754 infinity.

- Signaling NaNs are not required to be generated and exceptions are never raised. Signaling NaN may be converted to quiet NaNs values by any floating point instruction.

- By default, the implementation may perform optimizations on half, single, or double-precision floating-point instructions that ignore sign of a zero, or assume that arguments and results are not NaNs or infinities. If the entry point is declared with the `SignedZeroInfNanPreserve` execution mode, then NaNs, infinities, and the sign of zero must not be ignored.

  - The following core SPIR-V instructions must respect the `SignedZeroInfNanPreserve` execution mode: `OpPhi`, `OpSelect`, `OpReturnValue`, `OpVectorExtractDynamic`, `OpVectorInsertDynamic`, `OpVectorShuffle`, `OpCompositeConstruct`, `OpCompositeExtract`, `OpCompositeInsert`, `OpCopyObject`, `OpTranspose`, `OpFConvert`, `OpFNegate`, `OpFAdd`, `OpFSub`, `OpFMul`, `OpStore`. This execution mode must also be respected by `OpLoad` except for loads from the `Input` storage class in the fragment shader stage with the floating-point result type. Other SPIR-V instructions may also respect the `SignedZeroInfNanPreserve` execution mode.

- The following instructions must not flush denormalized values: `OpConstant`, `OpConstantComposite`, `OpSpecConstant`, `OpSpecConstantComposite`, `OpLoad`, `OpStore`, `OpBitcast`, `OpPhi`, `OpSelect`, `OpFunctionCall`, `OpReturnValue`, `OpVectorExtractDynamic`, `OpVectorInsertDynamic`, `OpVectorShuffle`, `OpCompositeConstruct`, `OpCompositeExtract`, `OpCompositeInsert`, `OpCopyMemory`, `OpCopyObject`.

- Denormalized values are supported.

  - By default, any half, single, or double-precision denormalized value input into a shader or potentially generated by any instruction (except those listed above) or any extended instructions for GLSL in a shader may be flushed to zero.

  - If the entry point is declared with the `DenormFlushToZero` execution mode then for the affected instuctions the denormalized result must be flushed to zero and the denormalized operands may be flushed to zero. Denormalized values obtained via unpacking an integer into a vector of values with smaller bit width and interpreting those values as floating-point numbers must be flushed to zero.

  - The following core SPIR-V instructions must respect the `DenormFlushToZero` execution mode: `OpSpecConstantOp` (with opcode `OpFConvert`), `OpFConvert`, `OpFNegate`, `OpFAdd`, `OpFSub`, `OpFMul`, `OpFDiv`, `OpFRem`, `OpFMod`, `OpVectorTimesScalar`, `OpMatrixTimesScalar`, `OpVectorTimesMatrix`, `OpMatrixTimesVector`, `OpMatrixTimesMatrix`, `OpOuterProduct`, `OpDot`; and the following extended instructions for GLSL: `Round`, `RoundEven`, `Trunc`, `FAbs`, `Floor`, `Ceil`, `Fract`, `Radians`, `Degrees`, `Sin`, `Cos`, `Tan`, `Asin`, `Acos`, `Atan`, `Sinh`, `Cosh`, `Tanh`, `Asinh`, `Acosh`, `Atanh`, `Atan2`, `Pow`, `Exp`, `Log`, `Exp2`, `Log2`, `Sqrt`, `InverseSqrt`, `Determinant`, `MatrixInverse`, `Modf`, `ModfStruct`, `FMin`, `FMax`, `FClamp`, `FMix`, `Step`, `SmoothStep`, `Fma`, `UnpackHalf2x16`, `UnpackDouble2x32`, `Length`, `Distance`, `Cross`, `Normalize`, `FaceForward`, `Reflect`, `Refract`, `NMin`, `NMax`, `NClamp`. Other SPIR-V instructions (except those excluded above) may also flush denormalized values.

  - The following core SPIR-V instructions must respect the `DenormPreserve` execution mode: `OpTranspose`, `OpSpecConstantOp`, `OpFConvert`, `OpFNegate`, `OpFAdd`, `OpFSub`, `OpFMul`, `OpVectorTimesScalar`, `OpMatrixTimesScalar`, `OpVectorTimesMatrix`, `OpMatrixTimesVector`, `OpMatrixTimesMatrix`, `OpOuterProduct`, `OpDot`, `OpFOrdEqual`, `OpFUnordEqual`, `OpFOrdNotEqual`, `OpFUnordNotEqual`, `OpFOrdLessThan`, `OpFUnordLessThan`, `OpFOrdGreaterThan`, `OpFUnordGreaterThan`, `OpFOrdLessThanEqual`, `OpFUnordLessThanEqual`, `OpFOrdGreaterThanEqual`, `OpFUnordGreaterThanEqual`; and the following extended instructions for GLSL: `FAbs`, `FSign`, `Radians`, `Degrees`, `FMin`, `FMax`, `FClamp`, `FMix`, `Fma`, `PackHalf2x16`, `PackDouble2x32`, `UnpackHalf2x16`, `UnpackDouble2x32`, `NMin`, `NMax`, `NClamp`. Other SPIR-V instructions may also preserve denorm values.

The precision of double-precision instructions is at least that of single precision.

The precision of operations is defined either in terms of rounding, as an error bound in ULP, or as inherited from a formula as follows.

Correctly Rounded

Operations described as “correctly rounded” will return the infinitely precise result, x, rounded so as to be representable in floating-point. The rounding mode is not specified, unless the entry point is declared with the `RoundingModeRTE` or the `RoundingModeRTZ` execution mode. These execution modes affect only correctly rounded SPIR-V instructions. These execution modes do not affect `OpQuantizeToF16`. If the rounding mode is not specified then this rounding is implementation specific, subject to the following rules. If x is exactly representable then x will be returned. Otherwise, either the floating-point value closest to and no less than x or the value closest to and no greater than x will be returned.

ULP

Where an error bound of n ULP (units in the last place) is given, for an operation with infinitely precise result x the value returned must be in the range [x - n × ulp(x), x + n × ulp(x)]. The function ulp(x) is defined as follows:

  If there exist non-equal floating-point numbers a and b such that a ≤ x ≤ b then ulp(x) is the minimum possible distance between such numbers, \(ulp(x) = \mathrm{min}_{a,b} | b - a |\). If such numbers do not exist then ulp(x) is defined to be the difference between the two finite floating-point numbers nearest to x.

Where the range of allowed return values includes any value of magnitude larger than that of the largest representable finite floating-point number, operations may, additionally, return either an infinity of the appropriate sign or the finite number with the largest magnitude of the appropriate sign. If the infinitely precise result of the operation is not mathematically defined then the value returned is undefined.

Inherited From …​

Where an operation’s precision is described as being inherited from a formula, the result returned must be at least as accurate as the result of computing an approximation to x using a formula equivalent to the given formula applied to the supplied inputs. Specifically, the formula given may be transformed using the mathematical associativity, commutativity and distributivity of the operators involved to yield an equivalent formula. The SPIR-V precision rules, when applied to each such formula and the given input values, define a range of permitted values. If NaN is one of the permitted values then the operation may return any result, otherwise let the largest permitted value in any of the ranges be Fmax and the smallest be Fmin. The operation must return a value in the range [x - E, x + E] where \(E = \mathrm{max} \left( | x - F_{\mathrm{min}} |, | x - F_{\mathrm{max}} | \right) \). If the entry point is declared with the `DenormFlushToZero` execution mode, then any intermediate denormal value(s) while evaluating the formula may be flushed to zero. Denormal final results must be flushed to zero. If the entry point is declared with the `DenormPreserve` execution mode, then denormals must be preserved throughout the formula.

For half- (16 bit) and single- (32 bit) precision instructions, precisions are required to be at least as follows:

Table 76. Precision of core SPIR-V Instructions
Instruction | Single precision, unless decorated with RelaxedPrecision | Half precision
--- | --- | ---
`OpFAdd` | Correctly rounded.
`OpFSub` | Correctly rounded.
`OpFMul`, `OpVectorTimesScalar`, `OpMatrixTimesScalar` | Correctly rounded.
`OpDot`(x, y) | Inherited from \(\sum_{i = 0}^{n - 1} x_{i} \times y_{i}\).
`OpFOrdEqual`, `OpFUnordEqual` | Correct result.
`OpFOrdLessThan`, `OpFUnordLessThan` | Correct result.
`OpFOrdGreaterThan`, `OpFUnordGreaterThan` | Correct result.
`OpFOrdLessThanEqual`, `OpFUnordLessThanEqual` | Correct result.
`OpFOrdGreaterThanEqual`, `OpFUnordGreaterThanEqual` | Correct result.
`OpFDiv`(x,y) | 2.5 ULP for |y| in the range [2-126, 2126]. | 2.5 ULP for |y| in the range [2-14, 214].
`OpFRem`(x,y) | Inherited from x - y × trunc(x/y).
`OpFMod`(x,y) | Inherited from x - y × floor(x/y).
conversions between types | Correctly rounded.

| Note The `OpFRem` and `OpFMod` instructions use cheap approximations of remainder, and the error can be large due to the discontinuity in trunc() and floor(). This can produce mathematically unexpected results in some cases, such as FMod(x,x) computing x rather than 0, and can also cause the result to have a different sign than the infinitely precise result.

Table 77. Precision of GLSL.std.450 Instructions
Instruction | Single precision, unless decorated with RelaxedPrecision | Half precision
--- | --- | ---
`fma`() | Inherited from `OpFMul` followed by `OpFAdd`.
`exp`(x), `exp2`(x) | \(3 + 2 \times \vert x \vert\) ULP. | \(1 + 2 \times \vert x \vert\) ULP.
`log`(), `log2`() | 3 ULP outside the range \([0.5, 2.0]\). Absolute error < \(2^{-21}\) inside the range \([0.5, 2.0]\). | 3 ULP outside the range \([0.5, 2.0]\). Absolute error < \(2^{-7}\) inside the range \([0.5, 2.0]\).
`pow`(x, y) | Inherited from `exp2`(y × `log2`(x)).
`sqrt`() | Inherited from 1.0 / `inversesqrt`().
`inversesqrt`() | 2 ULP.
`radians`(x) | Inherited from \(x \times \frac{\pi}{180}\).
`degrees`(x) | Inherited from \(x \times \frac{180}{\pi}\).
`sin`() | Absolute error \(\leq 2^{-11}\) inside the range \([-\pi, \pi]\). | Absolute error \(\leq 2^{-7}\) inside the range \([-\pi, \pi]\).
`cos`() | Absolute error \(\leq 2^{-11}\) inside the range \([-\pi, \pi]\). | Absolute error \(\leq 2^{-7}\) inside the range \([-\pi, \pi]\).
`tan`() | Inherited from \(\frac{\sin()}{\cos()}\).
`asin`(x) | Inherited from \(\mathrm{atan2}(x, sqrt(1.0 - x \times x))\).
`acos`(x) | Inherited from \(\mathrm{atan2}(sqrt(1.0 - x \times x), x)\).
`atan`(), `atan2`() | 4096 ULP | 5 ULP.
`sinh`(x) | Inherited from \((\exp(x) - \exp(-x)) \times 0.5\).
`cosh`(x) | Inherited from \((\exp(x) + \exp(-x)) \times 0.5\).
`tanh`() | Inherited from \(\frac{\sinh()}{\cosh()}\).
`asinh`(x) | Inherited from \(\log(x + sqrt(x \times x + 1.0))\).
`acosh`(x) | Inherited from \(\log(x + sqrt(x \times x - 1.0))\).
`atanh`(x) | Inherited from \(\log(\frac{1.0 + x}{1.0 - x}) \times 0.5\).
`frexp`() | Correctly rounded.
`ldexp`() | Correctly rounded.
`length`(x) | Inherited from \(sqrt(dot(x, x))\).
`distance`(x, y) | Inherited from \(length(x - y)\).
`cross`() | Inherited from `OpFSub`(`OpFMul`, `OpFMul`).
`normalize`(x) | Inherited from \(\frac{x}{length(x)}\).
`faceforward`(N, I, NRef) | Inherited from `dot`(NRef, I) < 0.0 ? N : -N.
`reflect`(x, y) | Inherited from x - 2.0 × `dot`(y, x) × y.
`refract`(I, N, eta) | Inherited from k < 0.0 ? 0.0 : eta × I - (eta × `dot`(N, I) + `sqrt`(k)) × N, where k = 1 - eta × eta × (1.0 - `dot`(N, I) × `dot`(N, I)).
`round` | Correctly rounded.
`roundEven` | Correctly rounded.
`trunc` | Correctly rounded.
`fabs` | Correctly rounded.
`fsign` | Correctly rounded.
`floor` | Correctly rounded.
`ceil` | Correctly rounded.
`fract` | Correctly rounded.
`modf` | Correctly rounded.
`fmin` | Correctly rounded.
`fmax` | Correctly rounded.
`fclamp` | Correctly rounded.
`fmix`(x, y, a) | Inherited from \(x \times (1.0 - a) + y \times a\).
`step` | Correctly rounded.
`smoothStep`(edge0, edge1, x) | Inherited from \(t \times t \times (3.0 - 2.0 \times t)\), where \(t = clamp(\frac{x - edge0}{edge1 - edge0}, 0.0, 1.0)\).
`nmin` | Correctly rounded.
`nmax` | Correctly rounded.
`nclamp` | Correctly rounded.

GLSL.std.450 extended instructions specifically defined in terms of the above instructions inherit the above errors. GLSL.std.450 extended instructions not listed above and not defined in terms of the above have undefined precision.

For the `OpSRem` and `OpSMod` instructions, if either operand is negative the result is undefined.

| Note While the `OpSRem` and `OpSMod` instructions are supported by the Vulkan environment, they require non-negative values and thus do not enable additional functionality beyond what `OpUMod` provides.

`OpCooperativeMatrixMulAddNV` performs its operations in an implementation-dependent order and internal precision.

### Compatibility Between SPIR-V Image Formats And Vulkan Formats

Images which are read from or written to by shaders must have SPIR-V image formats compatible with the Vulkan image formats backing the image under the circumstances described for texture image validation. The compatibile formats are:

Table 78. SPIR-V and Vulkan Image Format Compatibility
SPIR-V Image Format | Compatible Vulkan Format
--- | ---
`Rgba32f` | `VK_FORMAT_R32G32B32A32_SFLOAT`
`Rgba16f` | `VK_FORMAT_R16G16B16A16_SFLOAT`
`R32f` | `VK_FORMAT_R32_SFLOAT`
`Rgba8` | `VK_FORMAT_R8G8B8A8_UNORM`
`Rgba8Snorm` | `VK_FORMAT_R8G8B8A8_SNORM`
`Rg32f` | `VK_FORMAT_R32G32_SFLOAT`
`Rg16f` | `VK_FORMAT_R16G16_SFLOAT`
`R11fG11fB10f` | `VK_FORMAT_B10G11R11_UFLOAT_PACK32`
`R16f` | `VK_FORMAT_R16_SFLOAT`
`Rgba16` | `VK_FORMAT_R16G16B16A16_UNORM`
`Rgb10A2` | `VK_FORMAT_A2B10G10R10_UNORM_PACK32`
`Rg16` | `VK_FORMAT_R16G16_UNORM`
`Rg8` | `VK_FORMAT_R8G8_UNORM`
`R16` | `VK_FORMAT_R16_UNORM`
`R8` | `VK_FORMAT_R8_UNORM`
`Rgba16Snorm` | `VK_FORMAT_R16G16B16A16_SNORM`
`Rg16Snorm` | `VK_FORMAT_R16G16_SNORM`
`Rg8Snorm` | `VK_FORMAT_R8G8_SNORM`
`R16Snorm` | `VK_FORMAT_R16_SNORM`
`R8Snorm` | `VK_FORMAT_R8_SNORM`
`Rgba32i` | `VK_FORMAT_R32G32B32A32_SINT`
`Rgba16i` | `VK_FORMAT_R16G16B16A16_SINT`
`Rgba8i` | `VK_FORMAT_R8G8B8A8_SINT`
`R32i` | `VK_FORMAT_R32_SINT`
`Rg32i` | `VK_FORMAT_R32G32_SINT`
`Rg16i` | `VK_FORMAT_R16G16_SINT`
`Rg8i` | `VK_FORMAT_R8G8_SINT`
`R16i` | `VK_FORMAT_R16_SINT`
`R8i` | `VK_FORMAT_R8_SINT`
`Rgba32ui` | `VK_FORMAT_R32G32B32A32_UINT`
`Rgba16ui` | `VK_FORMAT_R16G16B16A16_UINT`
`Rgba8ui` | `VK_FORMAT_R8G8B8A8_UINT`
`R32ui` | `VK_FORMAT_R32_UINT`
`Rgb10a2ui` | `VK_FORMAT_A2B10G10R10_UINT_PACK32`
`Rg32ui` | `VK_FORMAT_R32G32_UINT`
`Rg16ui` | `VK_FORMAT_R16G16_UINT`
`Rg8ui` | `VK_FORMAT_R8G8_UINT`
`R16ui` | `VK_FORMAT_R16_UINT`
`R8ui` | `VK_FORMAT_R8_UINT`

## Appendix B: Memory Model

### Agent

Operation is a general term for any task that is executed on the system.

| An operation is by definition something that is executed, thus if an instruction is skipped due to flow control it does not constitute an operation.

Each operation is executed by a particular agent. Possible agents include each shader invocation, each host thread, and each fixed-function stage of the pipeline.

### Memory Location

A memory location identifies unique storage for 8 bits of data. Memory operations access a set of memory locations consisting of one or more memory locations at a time, e.g. an operation accessing a 32-bit integer in memory would read/write a set of four memory locations. Memory operations that access whole aggregates may access any padding bytes between elements or members, but no padding bytes at the end of the aggregate. Two sets of memory locations overlap if the intersection of their sets of memory locations is non-empty. A memory operation must not affect memory at a memory location not within its set of memory locations.

Memory locations for buffers and images are explicitly allocated in VkDeviceMemory objects, and are implicitly allocated for SPIR-V variables in each shader invocation.

### Allocation

The values stored in newly allocated memory locations are determined by a SPIR-V variable’s initializer, if present, or else are undefined. At the time an allocation is created there have been no memory operations to any of its memory locations. The initialization is not considered to be a memory operation.

| For tessellation control shader output variables, a consequence of initialization not being considered a memory operation is that some implementations may need to insert a barrier between the initialization of the output variables and any reads of those variables.

### Memory Operation

For an operation A and memory location M:

- A reads M if and only if the data stored in M is an input to A.

- A writes M if and only if the data output from A is stored to M.

- A accesses M if and only if it either reads or writes (or both) M.

| A write whose value is the same as what was already in those memory locations is still considered to be a write and has all the same effects.

### Reference

A reference is an object that a particular agent can use to access a set of memory locations. On the host, a reference is a host virtual address. On the device, a reference is:

- The descriptor that a variable is bound to, for variables in Image, Uniform, or StorageBuffer storage classes. If the variable is an array (or array of arrays, etc.) then each element of the array may be a unique reference.

- The address range for a buffer in `PhysicalStorageBuffer` storage class, where the base of the address range is queried with vkGetBufferDeviceAddress and the length of the range is the size of the buffer.

- The variable itself for variables in other storage classes.

Two memory accesses through distinct references may require availability and visibility operations as defined below.

### Program-Order

A dynamic instance of an instruction is defined in SPIR-V (https://www.khronos.org/registry/spir-v/specs/unified1/SPIRV.html#DynamicInstance) as a way of referring to a particular execution of a static instruction. Program-order is an ordering on dynamic instances of instructions executed by a single shader invocation:

- (Basic block): If instructions A and B are in the same basic block, and A is listed in the module before B, then the n’th dynamic instance of A is program-ordered before the n’th dynamic instance of B.

- (Branch): The dynamic instance of a branch or switch instruction is program-ordered before the dynamic instance of the OpLabel instruction to which it transfers control.

- (Call entry): The dynamic instance of an `OpFunctionCall` instruction is program-ordered before the dynamic instances of the `OpFunctionParameter` instructions and the body of the called function.

- (Call exit): The dynamic instance of the instruction following an `OpFunctionCall` instruction is program-ordered after the dynamic instance of the return instruction executed by the called function.

- (Transitive Closure): If dynamic instance A of any instruction is program-ordered before dynamic instance B of any instruction and B is program-ordered before dynamic instance C of any instruction then A is program-ordered before C.

- (Complete definition): No other dynamic instances are program-ordered.

For instructions executed on the host, the source language defines the program-order relation (e.g. as “sequenced-before”).

### Shader Call Related

Shader-call-related is an equivalence relation on invocations defined as the symmetric and transitive closure of:

- A is shader-call-related to B if A is created by an invocation repack instruction executed by B.

### Shader Call Order

Shader-call-order is a partial order on dynamic instances of instructions executed by invocations that are shader-call-related:

- (Program order): If dynamic instance A is program-ordered before B, then A is shader-call-ordered before B.

- (Shader call entry): If A is a dynamic instance of an invocation repack instruction and B is a dynamic instance executed by an invocation that is created by A, then A is shader-call-ordered before B.

- (Shader call exit): If A is a dynamic instance of an invocation repack instruction, B is the next dynamic instance executed by the same invocation, and C is a dynamic instance executed by an invocation that is created by A, then C is shader-call-ordered before B.

- (Transitive closure): If A is shader-call-ordered-before B and B is shader-call-ordered-before C, then A is shader-call-ordered-before C.

- (Complete definition): No other dynamic instances are shader-call-ordered.

### Scope

Atomic and barrier instructions include scopes which identify sets of shader invocations that must obey the requested ordering and atomicity rules of the operation, as defined below.

The various scopes are described in detail in the Shaders chapter.

### Atomic Operation

An atomic operation on the device is any SPIR-V operation whose name begins with `OpAtomic`. An atomic operation on the host is any operation performed with an std::atomic typed object.

Each atomic operation has a memory scope and a semantics. Informally, the scope determines which other agents it is atomic with respect to, and the semantics constrains its ordering against other memory accesses. Device atomic operations have explicit scopes and semantics. Each host atomic operation implicitly uses the `CrossDevice` scope, and uses a memory semantics equivalent to a C++ std::memory_order value of relaxed, acquire, release, acq_rel, or seq_cst.

Two atomic operations A and B are potentially-mutually-ordered if and only if all of the following are true:

- They access the same set of memory locations.

- They use the same reference.

- A is in the instance of B’s memory scope.

- B is in the instance of A’s memory scope.

- A and B are not the same operation (irreflexive).

Two atomic operations A and B are mutually-ordered if and only if they are potentially-mutually-ordered and any of the following are true:

- A and B are both device operations.

- A and B are both host operations.

- A is a device operation, B is a host operation, and the implementation supports concurrent host- and device-atomics.

| If two atomic operations are not mutually-ordered, and if their sets of memory locations overlap, then each must be synchronized against the other as if they were non-atomic operations.

### Scoped Modification Order

For a given atomic write A, all atomic writes that are mutually-ordered with A occur in an order known as A’s scoped modification order. A’s scoped modification order relates no other operations.

| Invocations outside the instance of A’s memory scope may observe the values at A’s set of memory locations becoming visible to it in an order that disagrees with the scoped modification order.

| It is valid to have non-atomic operations or atomics in a different scope instance to the same set of memory locations, as long as they are synchronized against each other as if they were non-atomic (if they are not, it is treated as a data race). That means this definition of A’s scoped modification order could include atomic operations that occur much later, after intervening non-atomics. That is a bit non-intuitive, but it helps to keep this definition simple and non-circular.

### Memory Semantics

Non-atomic memory operations, by default, may be observed by one agent in a different order than they were written by another agent.

Atomics and some synchronization operations include memory semantics, which are flags that constrain the order in which other memory accesses (including non-atomic memory accesses and availability and visibility operations) performed by the same agent can be observed by other agents, or can observe accesses by other agents.

Device instructions that include semantics are `OpAtomic`*, `OpControlBarrier`, `OpMemoryBarrier`, and `OpMemoryNamedBarrier`. Host instructions that include semantics are some std::atomic methods and memory fences.

SPIR-V supports the following memory semantics:

- Relaxed: No constraints on order of other memory accesses.

- Acquire: A memory read with this semantic performs an acquire operation. A memory barrier with this semantic is an acquire barrier.

- Release: A memory write with this semantic performs a release operation. A memory barrier with this semantic is a release barrier.

- AcquireRelease: A memory read-modify-write operation with this semantic performs both an acquire operation and a release operation, and inherits the limitations on ordering from both of those operations. A memory barrier with this semantic is both a release and acquire barrier.

| SPIR-V does not support “consume” semantics on the device.

The memory semantics operand also includes storage class semantics which indicate which storage classes are constrained by the synchronization. SPIR-V storage class semantics include:

- UniformMemory

- WorkgroupMemory

- ImageMemory

- OutputMemory

Each SPIR-V memory operation accesses a single storage class. Semantics in synchronization operations can include a combination of storage classes.

The UniformMemory storage class semantic applies to accesses to memory in the PhysicalStorageBuffer, `ShaderRecordBufferKHR`, Uniform and StorageBuffer storage classes. The WorkgroupMemory storage class semantic applies to accesses to memory in the Workgroup storage class. The ImageMemory storage class semantic applies to accesses to memory in the Image storage class. The OutputMemory storage class semantic applies to accesses to memory in the Output storage class.

| Informally, these constraints limit how memory operations can be reordered, and these limits apply not only to the order of accesses as performed in the agent that executes the instruction, but also to the order the effects of writes become visible to all other agents within the same instance of the instruction’s memory scope.

| Release and acquire operations in different threads can act as synchronization operations, to guarantee that writes that happened before the release are visible after the acquire. (This is not a formal definition, just an informative forward reference.)

| The OutputMemory storage class semantic is only useful in tessellation control shaders, which is the only execution model where output variables are shared between invocations.

The memory semantics operand also optionally includes availability and visibility flags, which apply optional availability and visibility operations as described in availability and visibility. The availability/visibility flags are:

- MakeAvailable: Semantics must be Release or AcquireRelease. Performs an availability operation before the release operation or barrier.

- MakeVisible: Semantics must be Acquire or AcquireRelease. Performs a visibility operation after the acquire operation or barrier.

The specifics of these operations are defined in Availability and Visibility Semantics.

Host atomic operations may support a different list of memory semantics and synchronization operations, depending on the host architecture and source language.

### Release Sequence

After an atomic operation A performs a release operation on a set of memory locations M, the release sequence headed by A is the longest continuous subsequence of A’s scoped modification order that consists of:

- the atomic operation A as its first element

- atomic read-modify-write operations on M by any agent

| The atomics in the last bullet must be mutually-ordered with A by virtue of being in A’s scoped modification order.

| This intentionally omits “atomic writes to M performed by the same agent that performed A”, which is present in the corresponding C++ definition.

### Synchronizes-With

Synchronizes-with is a relation between operations, where each operation is either an atomic operation or a memory barrier (aka fence on the host).

If A and B are atomic operations, then A synchronizes-with B if and only if all of the following are true:

- A performs a release operation

- B performs an acquire operation

- A and B are mutually-ordered

- B reads a value written by A or by an operation in the release sequence headed by A

`OpControlBarrier`, `OpMemoryBarrier`, and `OpMemoryNamedBarrier` are memory barrier instructions in SPIR-V.

If A is a release barrier and B is an atomic operation that performs an acquire operation, then A synchronizes-with B if and only if all of the following are true:

- there exists an atomic write X (with any memory semantics)

- A is program-ordered before X

- X and B are mutually-ordered

- B reads a value written by X or by an operation in the release sequence headed by X

  - If X is relaxed, it is still considered to head a hypothetical release sequence for this rule

- A and B are in the instance of each other’s memory scopes

- X’s storage class is in A’s semantics.

If A is an atomic operation that performs a release operation and B is an acquire barrier, then A synchronizes-with B if and only if all of the following are true:

- there exists an atomic read X (with any memory semantics)

- X is program-ordered before B

- X and A are mutually-ordered

- X reads a value written by A or by an operation in the release sequence headed by A

- A and B are in the instance of each other’s memory scopes

- X’s storage class is in B’s semantics.

If A is a release barrier and B is an acquire barrier, then A synchronizes-with B if all of the following are true:

- there exists an atomic write X (with any memory semantics)

- A is program-ordered before X

- there exists an atomic read Y (with any memory semantics)

- Y is program-ordered before B

- X and Y are mutually-ordered

- Y reads the value written by X or by an operation in the release sequence headed by X

  - If X is relaxed, it is still considered to head a hypothetical release sequence for this rule

- A and B are in the instance of each other’s memory scopes

- X’s and Y’s storage class is in A’s and B’s semantics.

  - NOTE: X and Y must have the same storage class, because they are mutually ordered.

If A is a release barrier and B is an acquire barrier and C is a control barrier (where A can optionally equal C and B can optionally equal C), then A synchronizes-with B if all of the following are true:

- A is program-ordered before (or equals) C

- C is program-ordered before (or equals) B

- A and B are in the instance of each other’s memory scopes

- A and B are in the instance of C’s execution scope

| This is similar to the barrier-barrier synchronization above, but with a control barrier filling the role of the relaxed atomics.

Let F be an ordering of fragment shader invocations, such that invocation F1 is ordered before invocation F2 if and only if F1 and F2 overlap as described in Fragment Shader Interlock and F1 executes the interlocked code before F2.

If A is an `OpEndInvocationInterlockEXT` instruction and B is an `OpBeginInvocationInterlockEXT` instruction, then A synchronizes-with B if the agent that executes A is ordered before the agent that executes B in F. A and B are both considered to have `FragmentInterlock` memory scope and semantics of UniformMemory and ImageMemory, and A is considered to have Release semantics and B is considered to have Acquire semantics.

If A is a release barrier and B is an acquire barrier, then A synchronizes-with B if all of the following are true:

- A is shader-call-ordered-before B

- A and B are in the instance of each other’s memory scopes

No other release and acquire barriers synchronize-with each other.

### System-Synchronizes-With

System-synchronizes-with is a relation between arbitrary operations on the device or host. Certain operations system-synchronize-with each other, which informally means the first operation occurs before the second and that the synchronization is performed without using application-visible memory accesses.

If there is an execution dependency between two operations A and B, then the operation in the first synchronization scope system-synchronizes-with the operation in the second synchronization scope.

| This covers all Vulkan synchronization primitives, including device operations executing before a synchronization primitive is signaled, wait operations happening before subsequent device operations, signal operations happening before host operations that wait on them, and host operations happening before vkQueueSubmit. The list is spread throughout the synchronization chapter, and is not repeated here.

System-synchronizes-with implicitly includes all storage class semantics and has `CrossDevice` scope.

If A system-synchronizes-with B, we also say A is system-synchronized-before B and B is system-synchronized-after A.

### Private vs. Non-Private

By default, non-atomic memory operations are treated as private, meaning such a memory operation is not intended to be used for communication with other agents. Memory operations with the NonPrivatePointer/NonPrivateTexel bit set are treated as non-private, and are intended to be used for communication with other agents.

More precisely, for private memory operations to be Location-Ordered between distinct agents requires using system-synchronizes-with rather than shader-based synchronization. Non-private memory operations still obey program-order.

Atomic operations are always considered non-private.

### Inter-Thread-Happens-Before

Let SC be a non-empty set of storage class semantics. Then (using template syntax) operation A inter-thread-happens-before<SC> operation B if and only if any of the following is true:

- A system-synchronizes-with B

- A synchronizes-with B, and both A and B have all of SC in their semantics

- A is an operation on memory in a storage class in SC or that has all of SC in its semantics, B is a release barrier or release atomic with all of SC in its semantics, and A is program-ordered before B

- A is an acquire barrier or acquire atomic with all of SC in its semantics, B is an operation on memory in a storage class in SC or that has all of SC in its semantics, and A is program-ordered before B

- A and B are both host operations and A inter-thread-happens-before B as defined in the host language spec

- A inter-thread-happens-before<SC> some X and X inter-thread-happens-before<SC> B

### Happens-Before

Operation A happens-before operation B if and only if any of the following is true:

- A is program-ordered before B

- A inter-thread-happens-before<SC> B for some set of storage classes SC

Happens-after is defined similarly.

| Unlike C++, happens-before is not always sufficient for a write to be visible to a read. Additional availability and visibility operations may be required for writes to be visible-to other memory accesses.

| Happens-before is not transitive, but each of program-order and inter-thread-happens-before<SC> are transitive. These can be thought of as covering the “single-threaded” case and the “multi-threaded” case, and it is not necessary (and not valid) to form chains between the two.

### Availability and Visibility

Availability and visibility are states of a write operation, which (informally) track how far the write has permeated the system, i.e. which agents and references are able to observe the write. Availability state is per memory domain. Visibility state is per (agent,reference) pair. Availability and visibility states are per-memory location for each write.

Memory domains are named according to the agents whose memory accesses use the domain. Domains used by shader invocations are organized hierarchically into multiple smaller memory domains which correspond to the different scopes. Each memory domain is considered the dual of a scope, and vice versa. The memory domains defined in Vulkan include:

- host - accessible by host agents

- device - accessible by all device agents for a particular device

- shader - accessible by shader agents for a particular device, corresponding to the `Device` scope

- queue family instance - accessible by shader agents in a single queue family, corresponding to the `QueueFamily` scope.

- fragment interlock instance - accessible by fragment shader agents that overlap, corresponding to the `FragmentInterlock` scope.

- shader call instance - accessible by shader agents that are shader-call-related, corresponding to the `ShaderCallKHR` scope.

- workgroup instance - accessible by shader agents in the same workgroup, corresponding to the `Workgroup` scope.

- subgroup instance - accessible by shader agents in the same subgroup, corresponding to the `Subgroup` scope.

The memory domains are nested in the order listed above, except for shader call instance domain, with memory domains later in the list nested in the domains earlier in the list. The shader call instance domain is at an implementation-dependent location in the list, and is nested according to that location. The shader call instance domain is not broader than the queue family instance domain.

| Memory domains do not correspond to storage classes or device-local and host-local VkDeviceMemory allocations, rather they indicate whether a write can be made visible only to agents in the same subgroup, same workgroup, overlapping fragment shader invocation, shader-call-related ray tracing invocation, in any shader invocation, or anywhere on the device, or host. The shader, queue family instance, fragment interlock instance, shader call instance, workgroup instance, and subgroup instance domains are only used for shader-based availability/visibility operatons, in other cases writes can be made available from/visible to the shader via the device domain.

Availability operations, visibility operations, and memory domain operations alter the state of the write operations that happen-before them, and which are included in their source scope to be available or visible to their destination scope.

- For an availability operation, the source scope is a set of (agent,reference,memory location) tuples, and the destination scope is a set of memory domains.

- For a memory domain operation, the source scope is a memory domain and the destination scope is a memory domain.

- For a visibility operation, the source scope is a set of memory domains and the destination scope is a set of (agent,reference,memory location) tuples.

How the scopes are determined depends on the specific operation. Availability and memory domain operations expand the set of memory domains to which the write is available. Visibility operations expand the set of (agent,reference,memory location) tuples to which the write is visible.

Recall that availability and visibility states are per-memory location, and let W be a write operation to one or more locations performed by agent A via reference R. Let L be one of the locations written. (W,L) (the write W to L), is initially not available to any memory domain and only visible to (A,R,L). An availability operation AV that happens-after W and that includes (A,R,L) in its source scope makes (W,L) available to the memory domains in its destination scope.

A memory domain operation DOM that happens-after AV and for which (W,L) is available in the source scope makes (W,L) available in the destination memory domain.

A visibility operation VIS that happens-after AV (or DOM) and for which (W,L) is available in any domain in the source scope makes (W,L) visible to all (agent,reference,L) tuples included in its destination scope.

If write W2 happens-after W, and their sets of memory locations overlap, then W will not be available/visible to all agents/references for those memory locations that overlap (and future AV/DOM/VIS ops cannot revive W’s write to those locations).

Availability, memory domain, and visibility operations are treated like other non-atomic memory accesses for the purpose of memory semantics, meaning they can be ordered by release-acquire sequences or memory barriers.

An availability chain is a sequence of availability operations to increasingly broad memory domains, where element N+1 of the chain is performed in the dual scope instance of the destination memory domain of element N and element N happens-before element N+1. An example is an availability operation with destination scope of the workgroup instance domain that happens-before an availability operation to the shader domain performed by an invocation in the same workgroup. An availability chain AVC that happens-after W and that includes (A,R,L) in the source scope makes (W,L) available to the memory domains in its final destination scope. An availability chain with a single element is just the availability operation.

Similarly, a visibility chain is a sequence of visibility operations from increasingly narrow memory domains, where element N of the chain is performed in the dual scope instance of the source memory domain of element N+1 and element N happens-before element N+1. An example is a visibility operation with source scope of the shader domain that happens-before a visibility operation with source scope of the workgroup instance domain performance by an invocation in the same workgroup. A visibility chain VISC that happens-after AVC (or DOM) and for which (W,L) is available in any domain in the source scope makes (W,L) visible to all (agent,reference,L) tuples included in its final destination scope. A visibility chain with a single element is just the visibility operation.

### Availability, Visibility, and Domain Operations

The following operations generate availability, visibility, and domain operations. When multiple availability/visibility/domain operations are described, they are system-synchronized-with each other in the order listed.

An operation that performs a memory dependency generates:

- If the source access mask includes `VK_ACCESS_HOST_WRITE_BIT`, then the dependency includes a memory domain operation from host domain to device domain.

- An availability operation with source scope of all writes in the first access scope of the dependency and a destination scope of the device domain.

- A visibility operation with source scope of the device domain and destination scope of the second access scope of the dependency.

- If the destination access mask includes `VK_ACCESS_HOST_READ_BIT` or `VK_ACCESS_HOST_WRITE_BIT`, then the dependency includes a memory domain operation from device domain to host domain.

vkFlushMappedMemoryRanges performs an availability operation, with a source scope of (agents,references) = (all host threads, all mapped memory ranges passed to the command), and destination scope of the host domain.

vkInvalidateMappedMemoryRanges performs a visibility operation, with a source scope of the host domain and a destination scope of (agents,references) = (all host threads, all mapped memory ranges passed to the command).

vkQueueSubmit performs a memory domain operation from host to device, and a visibility operation with source scope of the device domain and destination scope of all agents and references on the device.

### Availability and Visibility Semantics

A memory barrier or atomic operation via agent A that includes MakeAvailable in its semantics performs an availability operation whose source scope includes agent A and all references in the storage classes in that instruction’s storage class semantics, and all memory locations, and whose destination scope is a set of memory domains selected as specified below. The implicit availability operation is program-ordered between the barrier or atomic and all other operations program-ordered before the barrier or atomic.

A memory barrier or atomic operation via agent A that includes MakeVisible in its semantics performs a visibility operation whose source scope is a set of memory domains selected as specified below, and whose destination scope includes agent A and all references in the storage classes in that instruction’s storage class semantics, and all memory locations. The implicit visibility operation is program-ordered between the barrier or atomic and all other operations program-ordered after the barrier or atomic.

The memory domains are selected based on the memory scope of the instruction as follows:

- `Device` scope uses the shader domain

- `QueueFamily` scope uses the queue family instance domain

- `FragmentInterlock` scope uses the fragment interlock instance domain

- `ShaderCallKHR` scope uses the shader call instance domain

- `Workgroup` scope uses the workgroup instance domain

- `Subgroup` uses the subgroup instance domain

- `Invocation` perform no availability/visibility operations.

When an availability operation performed by an agent A includes a memory domain D in its destination scope, where D corresponds to scope instance S, it also includes the memory domains that correspond to each smaller scope instance S' that is a subset of S and that includes A. Similarly for visibility operations.

### Per-Instruction Availability and Visibility Semantics

A memory write instruction that includes MakePointerAvailable, or an image write instruction that includes MakeTexelAvailable, performs an availability operation whose source scope includes the agent and reference used to perform the write and the memory locations written by the instruction, and whose destination scope is a set of memory domains selected by the Scope operand specified in Availability and Visibility Semantics. The implicit availability operation is program-ordered between the write and all other operations program-ordered after the write.

A memory read instruction that includes MakePointerVisible, or an image read instruction that includes MakeTexelVisible, performs a visibility operation whose source scope is a set of memory domains selected by the Scope operand as specified in Availability and Visibility Semantics, and whose destination scope includes the agent and reference used to perform the read and the memory locations read by the instruction. The implicit visibility operation is program-ordered between read and all other operations program-ordered before the read.

| Although reads with per-instruction visibility only perform visibility ops from the shader or fragment interlock instance or shader call instance or workgroup instance or subgroup instance domain, they will also see writes that were made visible via the device domain, i.e. those writes previously performed by non-shader agents and made visible via API commands.

| It is expected that all invocations in a subgroup execute on the same processor with the same path to memory, and thus availability and visibility operations with subgroup scope can be expected to be “free”.

### Location-Ordered

Let X and Y be memory accesses to overlapping sets of memory locations M, where X != Y. Let (AX,RX) be the agent and reference used for X, and (AY,RY) be the agent and reference used for Y. For now, let “→” denote happens-before and “→rcpo” denote the reflexive closure of program-ordered before.

If D1 and D2 are different memory domains, then let DOM(D1,D2) be a memory domain operation from D1 to D2. Otherwise, let DOM(D,D) be a placeholder such that X→DOM(D,D)→Y if and only if X→Y.

X is location-ordered before Y for a location L in M if and only if any of the following is true:

- AX == AY and RX == RY and X→Y

  - NOTE: this case means no availability/visibility ops required when it is the same (agent,reference).

- X is a read, both X and Y are non-private, and X→Y

- X is a read, and X (transitively) system-synchronizes with Y

- If RX == RY and AX and AY access a common memory domain D (e.g. are in the same workgroup instance if D is the workgroup instance domain), and both X and Y are non-private:

  - X is a write, Y is a write, AVC(AX,RX,D,L) is an availability chain making (X,L) available to domain D, and X→rcpoAVC(AX,RX,D,L)→Y

  - X is a write, Y is a read, AVC(AX,RX,D,L) is an availability chain making (X,L) available to domain D, VISC(AY,RY,D,L) is a visibility chain making writes to L available in domain D visible to Y, and X→rcpoAVC(AX,RX,D,L)→VISC(AY,RY,D,L)→rcpoY

  - If VkPhysicalDeviceVulkanMemoryModelFeatures::`vulkanMemoryModelAvailabilityVisibilityChains` is `VK_FALSE`, then AVC and VISC must each only have a single element in the chain, in each sub-bullet above.

- Let DX and DY each be either the device domain or the host domain, depending on whether AX and AY execute on the device or host:

  - X is a write and Y is a write, and X→AV(AX,RX,DX,L)→DOM(DX,DY)→Y

  - X is a write and Y is a read, and X→AV(AX,RX,DX,L)→DOM(DX,DY)→VIS(AY,RY,DY,L)→Y

| The final bullet (synchronization through device/host domain) requires API-level synchronization operations, since the device/host domains are not accessible via shader instructions. And “device domain” is not to be confused with “device scope”, which synchronizes through the “shader domain”.

### Data Race

Let X and Y be operations that access overlapping sets of memory locations M, where X != Y, and at least one of X and Y is a write, and X and Y are not mutually-ordered atomic operations. If there does not exist a location-ordered relation between X and Y for each location in M, then there is a data race.

Applications must ensure that no data races occur during the execution of their application.

| Data races can only occur due to instructions that are actually executed, and for example an instruction skipped due to flow control must not contribute to a data race.

### Visible-To

Let X be a write and Y be a read whose sets of memory locations overlap, and let M be the set of memory locations that overlap. Let M2 be a non-empty subset of M. Then X is visible-to Y for memory locations M2 if and only if all of the following are true:

- X is location-ordered before Y for each location L in M2.

- There does not exist another write Z to any location L in M2 such that X is location-ordered before Z for location L and Z is location-ordered before Y for location L.

If X is visible-to Y, then Y reads the value written by X for locations M2.

| It is possible for there to be a write between X and Y that overwrites a subset of the memory locations, but the remaining memory locations (M2) will still be visible-to Y.

### Acyclicity

Reads-from is a relation between operations, where the first operation is a write, the second operation is a read, and the second operation reads the value written by the first operation. From-reads is a relation between operations, where the first operation is a read, the second operation is a write, and the first operation reads a value written earlier than the second operation in the second operation’s scoped modification order (or the first operation reads from the initial value, and the second operation is any write to the same locations).

Then the implementation must guarantee that no cycles exist in the union of the following relations:

- location-ordered

- scoped modification order (over all atomic writes)

- reads-from

- from-reads

| This is a "consistency" axiom, which informally guarantees that sequences of operations can’t violate causality.

#### Scoped Modification Order Coherence

Let A and B be mutually-ordered atomic operations, where A is location-ordered before B. Then the following rules are a consequence of acyclicity:

- If A and B are both reads and A does not read the initial value, then the write that A takes its value from must be earlier in its own scoped modification order than (or the same as) the write that B takes its value from (no cycles between location-order, reads-from, and from-reads).

- If A is a read and B is a write and A does not read the initial value, then A must take its value from a write earlier than B in B’s scoped modification order (no cycles between location-order, scope modification order, and reads-from).

- If A is a write and B is a read, then B must take its value from A or a write later than A in A’s scoped modification order (no cycles between location-order, scoped modification order, and from-reads).

- If A and B are both writes, then A must be earlier than B in A’s scoped modification order (no cycles between location-order and scoped modification order).

- If A is a write and B is a read-modify-write and B reads the value written by A, then B comes immediately after A in A’s scoped modification order (no cycles between scoped modification order and from-reads).

### Shader I/O

If a shader invocation A in a shader stage other than `Vertex` performs a memory read operation X from an object in storage class `CallableDataKHR`, `IncomingCallableDataKHR`, `RayPayloadKHR`, `HitAttributeKHR`, `IncomingRayPayloadKHR`, or `Input`, then X is system-synchronized-after all writes to the corresponding `CallableDataKHR`, `IncomingCallableDataKHR`, `RayPayloadKHR`, `HitAttributeKHR`, `IncomingRayPayloadKHR`, or `Output` storage variable(s) in the shader invocation(s) that contribute to generating invocation A, and those writes are all visible-to X.

| It is not necessary for the upstream shader invocations to have completed execution, they only need to have generated the output that is being read.

### Deallocation

A call to vkFreeMemory must happen-after all memory operations on all memory locations in that VkDeviceMemory object.

| Note Normally, device memory operations in a given queue are synchronized with vkFreeMemory by having a host thread wait on a fence signalled by that queue, and the wait happens-before the call to vkFreeMemory on the host.

The deallocation of SPIR-V variables is managed by the system and happens-after all operations on those variables.

### Informative Descriptions

This subsection is non-normative, and offers more easily understandable consequences of the memory model for app/compiler developers.

Let SC be the storage class(es) specified by a release or acquire operation or barrier.

- An atomic write with release semantics must not be reordered against any read or write to SC that is program-ordered before it (regardless of the storage class the atomic is in).

- An atomic read with acquire semantics must not be reordered against any read or write to SC that is program-ordered after it (regardless of the storage class the atomic is in).

- Any write to SC program-ordered after a release barrier must not be reordered against any read or write to SC program-ordered before that barrier.

- Any read from SC program-ordered before an acquire barrier must not be reordered against any read or write to SC program-ordered after the barrier.

A control barrier (even if it has no memory semantics) must not be reordered against any memory barriers.

This memory model allows memory accesses with and without availability and visibility operations, as well as atomic operations, all to be performed on the same memory location. This is critical to allow it to reason about memory that is reused in multiple ways, e.g. across the lifetime of different shader invocations or draw calls. While GLSL (and legacy SPIR-V) applies the “coherent” decoration to variables (for historical reasons), this model treats each memory access instruction as having optional implicit availability/visibility operations. GLSL to SPIR-V compilers should map all (non-atomic) operations on a coherent variable to Make{Pointer,Texel}{Available}{Visible} flags in this model.

Atomic operations implicitly have availability/visibility operations, and the scope of those operations is taken from the atomic operation’s scope.

### Tessellation Output Ordering

For SPIR-V that uses the Vulkan Memory Model, the `OutputMemory` storage class is used to synchronize accesses to tessellation control output variables. For legacy SPIR-V that does not enable the Vulkan Memory Model via `OpMemoryModel`, tessellation outputs can be ordered using a control barrier with no particular memory scope or semantics, as defined below.

Let X and Y be memory operations performed by shader invocations AX and AY. Operation X is tessellation-output-ordered before operation Y if and only if all of the following are true:

- There is a dynamic instance of an `OpControlBarrier` instruction C such that X is program-ordered before C in AX and C is program-ordered before Y in AY.

- AX and AY are in the same instance of C’s execution scope.

If shader invocations AX and AY in the `TessellationControl` execution model execute memory operations X and Y, respectively, on the `Output` storage class, and X is tessellation-output-ordered before Y with a scope of `Workgroup`, then X is location-ordered before Y, and if X is a write and Y is a read then X is visible-to Y.

### Cooperative Matrix Memory Access

For each dynamic instance of a cooperative matrix load or store instruction (`OpCooperativeMatrixLoadNV` or `OpCooperativeMatrixStoreNV`), a single implementation-dependent invocation within the instance of the matrix’s scope performs a non-atomic load or store (respectively) to each memory location that is defined to be accessed by the instruction.

## Appendix C: Compressed Image Formats

The compressed texture formats used by Vulkan are described in the specifically identified sections of the Khronos Data Format Specification, version 1.3.

Unless otherwise described, the quantities encoded in these compressed formats are treated as normalized, unsigned values.

Those formats listed as sRGB-encoded have in-memory representations of R, G and B components which are nonlinearly-encoded as R', G', and B'; any alpha component is unchanged. As part of filtering, the nonlinear R', G', and B' values are converted to linear R, G, and B components; any alpha component is unchanged. The conversion between linear and nonlinear encoding is performed as described in the “KHR_DF_TRANSFER_SRGB” section of the Khronos Data Format Specification.

### Block-Compressed Image Formats

BC1, BC2 and BC3 formats are described in “S3TC Compressed Texture Image Formats” chapter of the Khronos Data Format Specification. BC4 and BC5 are described in the “RGTC Compressed Texture Image Formats” chapter. BC6H and BC7 are described in the “BPTC Compressed Texture Image Formats” chapter.

Table 79. Mapping of Vulkan BC formats to descriptions
VkFormat | Khronos Data Format Specification description
--- | ---
Formats described in the “S3TC Compressed Texture Image Formats” chapter
`VK_FORMAT_BC1_RGB_UNORM_BLOCK` | BC1 with no alpha
`VK_FORMAT_BC1_RGB_SRGB_BLOCK` | BC1 with no alpha, sRGB-encoded
`VK_FORMAT_BC1_RGBA_UNORM_BLOCK` | BC1 with alpha
`VK_FORMAT_BC1_RGBA_SRGB_BLOCK` | BC1 with alpha, sRGB-encoded
`VK_FORMAT_BC2_UNORM_BLOCK` | BC2
`VK_FORMAT_BC2_SRGB_BLOCK` | BC2, sRGB-encoded
`VK_FORMAT_BC3_UNORM_BLOCK` | BC3
`VK_FORMAT_BC3_SRGB_BLOCK` | BC3, sRGB-encoded
Formats described in the “RGTC Compressed Texture Image Formats” chapter
`VK_FORMAT_BC4_UNORM_BLOCK` | BC4 unsigned
`VK_FORMAT_BC4_SNORM_BLOCK` | BC4 signed
`VK_FORMAT_BC5_UNORM_BLOCK` | BC5 unsigned
`VK_FORMAT_BC5_SNORM_BLOCK` | BC5 signed
Formats described in the “BPTC Compressed Texture Image Formats” chapter
`VK_FORMAT_BC6H_UFLOAT_BLOCK` | BC6H (unsigned version)
`VK_FORMAT_BC6H_SFLOAT_BLOCK` | BC6H (signed version)
`VK_FORMAT_BC7_UNORM_BLOCK` | BC7
`VK_FORMAT_BC7_SRGB_BLOCK` | BC7, sRGB-encoded

### ETC Compressed Image Formats

The following formats are described in the “ETC2 Compressed Texture Image Formats” chapter of the Khronos Data Format Specification.

Table 80. Mapping of Vulkan ETC formats to descriptions
VkFormat | Khronos Data Format Specification description
--- | ---
`VK_FORMAT_ETC2_R8G8B8_UNORM_BLOCK` | RGB ETC2
`VK_FORMAT_ETC2_R8G8B8_SRGB_BLOCK` | RGB ETC2 with sRGB encoding
`VK_FORMAT_ETC2_R8G8B8A1_UNORM_BLOCK` | RGB ETC2 with punch-through alpha
`VK_FORMAT_ETC2_R8G8B8A1_SRGB_BLOCK` | RGB ETC2 with punch-through alpha and sRGB
`VK_FORMAT_ETC2_R8G8B8A8_UNORM_BLOCK` | RGBA ETC2
`VK_FORMAT_ETC2_R8G8B8A8_SRGB_BLOCK` | RGBA ETC2 with sRGB encoding
`VK_FORMAT_EAC_R11_UNORM_BLOCK` | Unsigned R11 EAC
`VK_FORMAT_EAC_R11_SNORM_BLOCK` | Signed R11 EAC
`VK_FORMAT_EAC_R11G11_UNORM_BLOCK` | Unsigned RG11 EAC
`VK_FORMAT_EAC_R11G11_SNORM_BLOCK` | Signed RG11 EAC

### ASTC Compressed Image Formats

ASTC formats are described in the “ASTC Compressed Texture Image Formats” chapter of the Khronos Data Format Specification.

Table 81. Mapping of Vulkan ASTC formats to descriptions
VkFormat | Compressed texel block dimensions | sRGB-encoded | Profile
--- | --- | --- | ---
`VK_FORMAT_ASTC_4x4_UNORM_BLOCK` | 4 × 4 | No | LDR
`VK_FORMAT_ASTC_4x4_SRGB_BLOCK` | 4 × 4 | Yes | LDR
`VK_FORMAT_ASTC_5x4_UNORM_BLOCK` | 5 × 4 | No | LDR
`VK_FORMAT_ASTC_5x4_SRGB_BLOCK` | 5 × 4 | Yes | LDR
`VK_FORMAT_ASTC_5x5_UNORM_BLOCK` | 5 × 5 | No | LDR
`VK_FORMAT_ASTC_5x5_SRGB_BLOCK` | 5 × 5 | Yes | LDR
`VK_FORMAT_ASTC_6x5_UNORM_BLOCK` | 6 × 5 | No | LDR
`VK_FORMAT_ASTC_6x5_SRGB_BLOCK` | 6 × 5 | Yes | LDR
`VK_FORMAT_ASTC_6x6_UNORM_BLOCK` | 6 × 6 | No | LDR
`VK_FORMAT_ASTC_6x6_SRGB_BLOCK` | 6 × 6 | Yes | LDR
`VK_FORMAT_ASTC_8x5_UNORM_BLOCK` | 8 × 5 | No | LDR
`VK_FORMAT_ASTC_8x5_SRGB_BLOCK` | 8 × 5 | Yes | LDR
`VK_FORMAT_ASTC_8x6_UNORM_BLOCK` | 8 × 6 | No | LDR
`VK_FORMAT_ASTC_8x6_SRGB_BLOCK` | 8 × 6 | Yes | LDR
`VK_FORMAT_ASTC_8x8_UNORM_BLOCK` | 8 × 8 | No | LDR
`VK_FORMAT_ASTC_8x8_SRGB_BLOCK` | 8 × 8 | Yes | LDR
`VK_FORMAT_ASTC_10x5_UNORM_BLOCK` | 10 × 5 | No | LDR
`VK_FORMAT_ASTC_10x5_SRGB_BLOCK` | 10 × 5 | Yes | LDR
`VK_FORMAT_ASTC_10x6_UNORM_BLOCK` | 10 × 6 | No | LDR
`VK_FORMAT_ASTC_10x6_SRGB_BLOCK` | 10 × 6 | Yes | LDR
`VK_FORMAT_ASTC_10x8_UNORM_BLOCK` | 10 × 8 | No | LDR
`VK_FORMAT_ASTC_10x8_SRGB_BLOCK` | 10 × 8 | Yes | LDR
`VK_FORMAT_ASTC_10x10_UNORM_BLOCK` | 10 × 10 | No | LDR
`VK_FORMAT_ASTC_10x10_SRGB_BLOCK` | 10 × 10 | Yes | LDR
`VK_FORMAT_ASTC_12x10_UNORM_BLOCK` | 12 × 10 | No | LDR
`VK_FORMAT_ASTC_12x10_SRGB_BLOCK` | 12 × 10 | Yes | LDR
`VK_FORMAT_ASTC_12x12_UNORM_BLOCK` | 12 × 12 | No | LDR
`VK_FORMAT_ASTC_12x12_SRGB_BLOCK` | 12 × 12 | Yes | LDR
`VK_FORMAT_ASTC_4x4_SFLOAT_BLOCK_EXT` | 4 × 4 | No | HDR
`VK_FORMAT_ASTC_5x4_SFLOAT_BLOCK_EXT` | 5 × 4 | No | HDR
`VK_FORMAT_ASTC_5x5_SFLOAT_BLOCK_EXT` | 5 × 5 | No | HDR
`VK_FORMAT_ASTC_6x5_SFLOAT_BLOCK_EXT` | 6 × 5 | No | HDR
`VK_FORMAT_ASTC_6x6_SFLOAT_BLOCK_EXT` | 6 × 6 | No | HDR
`VK_FORMAT_ASTC_8x5_SFLOAT_BLOCK_EXT` | 8 × 5 | No | HDR
`VK_FORMAT_ASTC_8x6_SFLOAT_BLOCK_EXT` | 8 × 6 | No | HDR
`VK_FORMAT_ASTC_8x8_SFLOAT_BLOCK_EXT` | 8 × 8 | No | HDR
`VK_FORMAT_ASTC_10x5_SFLOAT_BLOCK_EXT` | 10 × 5 | No | HDR
`VK_FORMAT_ASTC_10x6_SFLOAT_BLOCK_EXT` | 10 × 6 | No | HDR
`VK_FORMAT_ASTC_10x8_SFLOAT_BLOCK_EXT` | 10 × 8 | No | HDR
`VK_FORMAT_ASTC_10x10_SFLOAT_BLOCK_EXT` | 10 × 10 | No | HDR
`VK_FORMAT_ASTC_12x10_SFLOAT_BLOCK_EXT` | 12 × 10 | No | HDR
`VK_FORMAT_ASTC_12x12_SFLOAT_BLOCK_EXT` | 12 × 12 | No | HDR

#### ASTC decode mode

If the `VK_EXT_astc_decode_mode` extension is enabled, the decode mode is determined as follows:

Table 82. Mapping of Vulkan ASTC decoding format to ASTC decoding modes
VkFormat | Decoding mode
--- | ---
`VK_FORMAT_R16G16B16A16_SFLOAT` | decode_float16
`VK_FORMAT_R8G8B8A8_UNORM` | decode_unorm8
`VK_FORMAT_E5B9G9R9_UFLOAT_PACK32` | decode_rgb9e5

Otherwise, the ASTC decode mode is decode_float16.

### PVRTC Compressed Image Formats

PVRTC formats are described in the “PVRTC Compressed Texture Image Formats” chapter of the Khronos Data Format Specification.

Table 83. Mapping of Vulkan PVRTC formats to descriptions
VkFormat | Compressed texel block dimensions | sRGB-encoded
--- | --- | ---
`VK_FORMAT_PVRTC1_2BPP_UNORM_BLOCK_IMG` | 8 × 4 | No
`VK_FORMAT_PVRTC1_4BPP_UNORM_BLOCK_IMG` | 4 × 4 | No
`VK_FORMAT_PVRTC2_2BPP_UNORM_BLOCK_IMG` | 8 × 4 | No
`VK_FORMAT_PVRTC2_4BPP_UNORM_BLOCK_IMG` | 4 × 4 | No
`VK_FORMAT_PVRTC1_2BPP_SRGB_BLOCK_IMG` | 8 × 4 | Yes
`VK_FORMAT_PVRTC1_4BPP_SRGB_BLOCK_IMG` | 4 × 4 | Yes
`VK_FORMAT_PVRTC2_2BPP_SRGB_BLOCK_IMG` | 8 × 4 | Yes
`VK_FORMAT_PVRTC2_4BPP_SRGB_BLOCK_IMG` | 4 × 4 | Yes

## Appendix D: Core Revisions (Informative)

New minor versions of the Vulkan API are defined periodically by the Khronos Vulkan Working Group. These consist of some amount of additional functionality added to the core API, potentially including both new functionality and functionality promoted from extensions.

It is possible to build the specification for earlier versions, but to aid readability of the latest versions, this appendix gives an overview of the changes as compared to earlier versions.

### Version 1.2

Vulkan Version 1.2 promoted a number of key extensions into the core API:

- `VK_KHR_8bit_storage`

- `VK_KHR_buffer_device_address`

- `VK_KHR_create_renderpass2`

- `VK_KHR_depth_stencil_resolve`

- `VK_KHR_draw_indirect_count`

- `VK_KHR_driver_properties`

- `VK_KHR_image_format_list`

- `VK_KHR_imageless_framebuffer`

- `VK_KHR_sampler_mirror_clamp_to_edge`

- `VK_KHR_separate_depth_stencil_layouts`

- `VK_KHR_shader_atomic_int64`

- `VK_KHR_shader_float16_int8`

- `VK_KHR_shader_float_controls`

- `VK_KHR_shader_subgroup_extended_types`

- `VK_KHR_spirv_1_4`

- `VK_KHR_timeline_semaphore`

- `VK_KHR_uniform_buffer_standard_layout`

- `VK_KHR_vulkan_memory_model`

- `VK_EXT_descriptor_indexing`

- `VK_EXT_host_query_reset`

- `VK_EXT_sampler_filter_minmax`

- `VK_EXT_scalar_block_layout`

- `VK_EXT_separate_stencil_usage`

- `VK_EXT_shader_viewport_index_layer`

All differences in behavior between these extensions and the corresponding Vulkan 1.2 functionality are summarized below.

#### Differences relative to `VK_KHR_8bit_storage`

If the `VK_KHR_8bit_storage` extension is not supported, support for the SPIR-V `StorageBuffer8BitAccess` capability in shader modules is optional. Support for this feature is defined by VkPhysicalDeviceVulkan12Features::`storageBuffer8BitAccess` when queried via vkGetPhysicalDeviceFeatures2.

#### Differences relative to `VK_KHR_draw_indirect_count`

If the `VK_KHR_draw_indirect_count` extension is not supported, support for the entry points vkCmdDrawIndirectCount and vkCmdDrawIndexedIndirectCount is optional. Support for this feature is defined by VkPhysicalDeviceVulkan12Features::`drawIndirectCount` when queried via vkGetPhysicalDeviceFeatures2.

#### Differences relative to `VK_KHR_sampler_mirror_clamp_to_edge`

If the `VK_KHR_sampler_mirror_clamp_to_edge` extension is not supported, support for the VkSamplerAddressMode `VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE` is optional. Support for this feature is defined by VkPhysicalDeviceVulkan12Features::`samplerMirrorClampToEdge` when queried via vkGetPhysicalDeviceFeatures2.

#### Differences relative to `VK_EXT_descriptor_indexing`

If the `VK_EXT_descriptor_indexing` extension is not supported, support for the descriptorIndexing feature is optional. Support for this feature is defined by VkPhysicalDeviceVulkan12Features::`descriptorIndexing` when queried via vkGetPhysicalDeviceFeatures2.

#### Differences relative to `VK_EXT_scalar_block_layout`

If the `VK_EXT_scalar_block_layout` extension is not supported, support for the scalarBlockLayout feature is optional. Support for this feature is defined by VkPhysicalDeviceVulkan12Features::`scalarBlockLayout` when queried via vkGetPhysicalDeviceFeatures2.

#### Differences relative to `VK_EXT_shader_viewport_index_layer`

If the `VK_EXT_shader_viewport_index_layer` extension is not supported, support for the `ShaderViewportIndexLayerEXT` SPIR-V capability is optional. Support for this feature is defined by VkPhysicalDeviceVulkan12Features::`shaderOutputViewportIndex` and VkPhysicalDeviceVulkan12Features::`shaderOutputLayer` when queried via vkGetPhysicalDeviceFeatures2.

#### Additional Vulkan 1.2 Feature Support

In addition to the promoted extensions described above, Vulkan 1.2 added support for:

- SPIR-V version 1.4.

- SPIR-V version 1.5.

- The samplerMirrorClampToEdge feature which indicates whether the implementation supports the `VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE` sampler address mode.

- The `ShaderNonUniform` capability in SPIR-V version 1.5.

- The shaderOutputViewportIndex feature which indicates that the `ShaderViewportIndex` capability can be used.

- The shaderOutputLayer feature which indicates that the `ShaderLayer` capability can be used.

- The subgroupBroadcastDynamicId feature which allows the “Id” operand of `OpGroupNonUniformBroadcast` to be dynamically uniform within a subgroup, and the “Index” operand of `OpGroupNonUniformQuadBroadcast` to be dynamically uniform within a derivative group, in shader modules of version 1.5 or higher.

- The drawIndirectCount feature which indicates whether the vkCmdDrawIndirectCount and vkCmdDrawIndexedIndirectCount functions can be used.

- The descriptorIndexing feature which indicates the implementation supports the minimum number of descriptor indexing features as defined in the Feature Requirements section.

- The samplerFilterMinmax feature which indicates whether the implementation supports the minimum number of image formats that support the `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_MINMAX_BIT` feature bit as defined by the `filterMinmaxSingleComponentFormats` property minimum requirements.

- The framebufferIntegerColorSampleCounts limit which indicates the color sample counts that are supported for all framebuffer color attachments with integer formats.

#### New Object Types

#### New Defines

- VK_API_VERSION_1_2

#### New Enum Constants

#### New Enums

#### New Structures

- VkPhysicalDeviceVulkan11Features

- VkPhysicalDeviceVulkan11Properties

- VkPhysicalDeviceVulkan12Features

- VkPhysicalDeviceVulkan12Properties

- VkPhysicalDevice8BitStorageFeatures

- VkPhysicalDeviceBufferDeviceAddressFeatures

- VkBufferDeviceAddressInfo

- VkBufferOpaqueCaptureAddressCreateInfo

- VkMemoryOpaqueCaptureAddressAllocateInfo

- VkDeviceMemoryOpaqueCaptureAddressInfo

- VkAttachmentDescription2

- VkAttachmentReference2

- VkSubpassDescription2

- VkSubpassDependency2

- VkRenderPassCreateInfo2

- VkSubpassBeginInfo

- VkSubpassEndInfo

- VkPhysicalDeviceDepthStencilResolveProperties

- VkSubpassDescriptionDepthStencilResolve

- VkConformanceVersion

- VkPhysicalDeviceDriverProperties

- VkImageFormatListCreateInfo

- VkPhysicalDeviceImagelessFramebufferFeatures

- VkFramebufferAttachmentsCreateInfo

- VkFramebufferAttachmentImageInfo

- VkRenderPassAttachmentBeginInfo

- VkPhysicalDeviceSeparateDepthStencilLayoutsFeatures

- VkAttachmentReferenceStencilLayout

- VkAttachmentDescriptionStencilLayout

- VkPhysicalDeviceShaderAtomicInt64Features

- VkPhysicalDeviceShaderFloat16Int8Features

- VkPhysicalDeviceFloatControlsProperties

- VkPhysicalDeviceShaderSubgroupExtendedTypesFeatures

- VkPhysicalDeviceTimelineSemaphoreFeatures

- VkPhysicalDeviceTimelineSemaphoreProperties

- VkSemaphoreTypeCreateInfo

- VkTimelineSemaphoreSubmitInfo

- VkSemaphoreWaitInfo

- VkSemaphoreSignalInfo

- VkPhysicalDeviceUniformBufferStandardLayoutFeatures

- VkPhysicalDeviceVulkanMemoryModelFeatures

- VkDescriptorSetLayoutBindingFlagsCreateInfo

- VkPhysicalDeviceDescriptorIndexingFeatures

- VkPhysicalDeviceDescriptorIndexingProperties

- VkDescriptorSetVariableDescriptorCountAllocateInfo

- VkDescriptorSetVariableDescriptorCountLayoutSupport

- VkPhysicalDeviceHostQueryResetFeatures

- VkSamplerReductionModeCreateInfo

- VkPhysicalDeviceSamplerFilterMinmaxProperties

- VkPhysicalDeviceScalarBlockLayoutFeatures

- VkImageStencilUsageCreateInfo

#### New Functions

- vkGetBufferDeviceAddress

- vkGetBufferOpaqueCaptureAddress

- vkGetDeviceMemoryOpaqueCaptureAddress

- vkCreateRenderPass2

- vkCmdBeginRenderPass2

- vkCmdNextSubpass2

- vkCmdEndRenderPass2

- vkCmdDrawIndirectCount

- vkCmdDrawIndexedIndirectCount

- vkGetSemaphoreCounterValue

- vkWaitSemaphores

- vkSignalSemaphore

- vkResetQueryPool

### Version 1.1

Vulkan Version 1.1 promoted a number of key extensions into the core API:

- `VK_KHR_16bit_storage`

- `VK_KHR_bind_memory2`

- `VK_KHR_dedicated_allocation`

- `VK_KHR_descriptor_update_template`

- `VK_KHR_device_group`

- `VK_KHR_device_group_creation`

- `VK_KHR_external_fence`

- `VK_KHR_external_fence_capabilities`

- `VK_KHR_external_memory`

- `VK_KHR_external_memory_capabilities`

- `VK_KHR_external_semaphore`

- `VK_KHR_external_semaphore_capabilities`

- `VK_KHR_get_memory_requirements2`

- `VK_KHR_get_physical_device_properties2`

- `VK_KHR_maintenance1`

- `VK_KHR_maintenance2`

- `VK_KHR_maintenance3`

- `VK_KHR_multiview`

- `VK_KHR_relaxed_block_layout`

- `VK_KHR_sampler_ycbcr_conversion`

- `VK_KHR_shader_draw_parameters`

- `VK_KHR_storage_buffer_storage_class`

- `VK_KHR_variable_pointers`

The only changes to the functionality added by these extensions were to `VK_KHR_shader_draw_parameters`, which had the `shaderDrawParameters` feature bit added to determine support in the core API, and `variablePointersStorageBuffer` from `VK_KHR_variable_pointers` was made optional.

Additionally, Vulkan 1.1 added support for group operations with subgroup scope, protected memory, and a new command to enumerate the instance version.

#### New Object Types

- VkDescriptorUpdateTemplate

- VkSamplerYcbcrConversion

#### New Defines

- VK_API_VERSION_1_1

#### New Enum Constants

- Extending VkBufferCreateFlagBits:

  - `VK_BUFFER_CREATE_PROTECTED_BIT`

- Extending VkCommandPoolCreateFlagBits:

  - `VK_COMMAND_POOL_CREATE_PROTECTED_BIT`

- Extending VkDependencyFlagBits:

  - `VK_DEPENDENCY_DEVICE_GROUP_BIT`

  - `VK_DEPENDENCY_VIEW_LOCAL_BIT`

- Extending VkDeviceQueueCreateFlagBits:

  - `VK_DEVICE_QUEUE_CREATE_PROTECTED_BIT`

- Extending VkFormat:

  - `VK_FORMAT_G8B8G8R8_422_UNORM`

  - `VK_FORMAT_B8G8R8G8_422_UNORM`

  - `VK_FORMAT_G8_B8_R8_3PLANE_420_UNORM`

  - `VK_FORMAT_G8_B8R8_2PLANE_420_UNORM`

  - `VK_FORMAT_G8_B8_R8_3PLANE_422_UNORM`

  - `VK_FORMAT_G8_B8R8_2PLANE_422_UNORM`

  - `VK_FORMAT_G8_B8_R8_3PLANE_444_UNORM`

  - `VK_FORMAT_R10X6_UNORM_PACK16`

  - `VK_FORMAT_R10X6G10X6_UNORM_2PACK16`

  - `VK_FORMAT_R10X6G10X6B10X6A10X6_UNORM_4PACK16`

  - `VK_FORMAT_G10X6B10X6G10X6R10X6_422_UNORM_4PACK16`

  - `VK_FORMAT_B10X6G10X6R10X6G10X6_422_UNORM_4PACK16`

  - `VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_420_UNORM_3PACK16`

  - `VK_FORMAT_G10X6_B10X6R10X6_2PLANE_420_UNORM_3PACK16`

  - `VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_422_UNORM_3PACK16`

  - `VK_FORMAT_G10X6_B10X6R10X6_2PLANE_422_UNORM_3PACK16`

  - `VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_444_UNORM_3PACK16`

  - `VK_FORMAT_R12X4_UNORM_PACK16`

  - `VK_FORMAT_R12X4G12X4_UNORM_2PACK16`

  - `VK_FORMAT_R12X4G12X4B12X4A12X4_UNORM_4PACK16`

  - `VK_FORMAT_G12X4B12X4G12X4R12X4_422_UNORM_4PACK16`

  - `VK_FORMAT_B12X4G12X4R12X4G12X4_422_UNORM_4PACK16`

  - `VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_420_UNORM_3PACK16`

  - `VK_FORMAT_G12X4_B12X4R12X4_2PLANE_420_UNORM_3PACK16`

  - `VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_422_UNORM_3PACK16`

  - `VK_FORMAT_G12X4_B12X4R12X4_2PLANE_422_UNORM_3PACK16`

  - `VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_444_UNORM_3PACK16`

  - `VK_FORMAT_G16B16G16R16_422_UNORM`

  - `VK_FORMAT_B16G16R16G16_422_UNORM`

  - `VK_FORMAT_G16_B16_R16_3PLANE_420_UNORM`

  - `VK_FORMAT_G16_B16R16_2PLANE_420_UNORM`

  - `VK_FORMAT_G16_B16_R16_3PLANE_422_UNORM`

  - `VK_FORMAT_G16_B16R16_2PLANE_422_UNORM`

  - `VK_FORMAT_G16_B16_R16_3PLANE_444_UNORM`

- Extending VkFormatFeatureFlagBits:

  - `VK_FORMAT_FEATURE_TRANSFER_SRC_BIT`

  - `VK_FORMAT_FEATURE_TRANSFER_DST_BIT`

  - `VK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BIT`

  - `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_LINEAR_FILTER_BIT`

  - `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_SEPARATE_RECONSTRUCTION_FILTER_BIT`

  - `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_BIT`

  - `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_FORCEABLE_BIT`

  - `VK_FORMAT_FEATURE_DISJOINT_BIT`

  - `VK_FORMAT_FEATURE_COSITED_CHROMA_SAMPLES_BIT`

- Extending VkImageAspectFlagBits:

  - `VK_IMAGE_ASPECT_PLANE_0_BIT`

  - `VK_IMAGE_ASPECT_PLANE_1_BIT`

  - `VK_IMAGE_ASPECT_PLANE_2_BIT`

- Extending VkImageCreateFlagBits:

  - `VK_IMAGE_CREATE_ALIAS_BIT`

  - `VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT`

  - `VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT`

  - `VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT`

  - `VK_IMAGE_CREATE_EXTENDED_USAGE_BIT`

  - `VK_IMAGE_CREATE_PROTECTED_BIT`

  - `VK_IMAGE_CREATE_DISJOINT_BIT`

- Extending VkImageCreateFlagBits:

  - `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL`

  - `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL`

- Extending VkMemoryHeapFlagBits:

  - `VK_MEMORY_HEAP_MULTI_INSTANCE_BIT`

- Extending VkMemoryPropertyFlagBits:

  - `VK_MEMORY_PROPERTY_PROTECTED_BIT`

- Extending VkObjectType:

  - `VK_OBJECT_TYPE_SAMPLER_YCBCR_CONVERSION`

  - `VK_OBJECT_TYPE_DESCRIPTOR_UPDATE_TEMPLATE`

- Extending VkPipelineCreateFlagBits:

  - `VK_PIPELINE_CREATE_VIEW_INDEX_FROM_DEVICE_INDEX_BIT`

  - `VK_PIPELINE_CREATE_DISPATCH_BASE`

- Extending VkQueueFlagBits:

  - `VK_QUEUE_PROTECTED_BIT`

- Extending VkResult:

  - `VK_ERROR_OUT_OF_POOL_MEMORY`

  - `VK_ERROR_INVALID_EXTERNAL_HANDLE`

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SUBGROUP_PROPERTIES`

  - `VK_STRUCTURE_TYPE_BIND_BUFFER_MEMORY_INFO`

  - `VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_INFO`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_16BIT_STORAGE_FEATURES`

  - `VK_STRUCTURE_TYPE_MEMORY_DEDICATED_REQUIREMENTS`

  - `VK_STRUCTURE_TYPE_MEMORY_DEDICATED_ALLOCATE_INFO`

  - `VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_FLAGS_INFO`

  - `VK_STRUCTURE_TYPE_DEVICE_GROUP_RENDER_PASS_BEGIN_INFO`

  - `VK_STRUCTURE_TYPE_DEVICE_GROUP_COMMAND_BUFFER_BEGIN_INFO`

  - `VK_STRUCTURE_TYPE_DEVICE_GROUP_SUBMIT_INFO`

  - `VK_STRUCTURE_TYPE_DEVICE_GROUP_BIND_SPARSE_INFO`

  - `VK_STRUCTURE_TYPE_BIND_BUFFER_MEMORY_DEVICE_GROUP_INFO`

  - `VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_DEVICE_GROUP_INFO`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_GROUP_PROPERTIES`

  - `VK_STRUCTURE_TYPE_DEVICE_GROUP_DEVICE_CREATE_INFO`

  - `VK_STRUCTURE_TYPE_BUFFER_MEMORY_REQUIREMENTS_INFO_2`

  - `VK_STRUCTURE_TYPE_IMAGE_MEMORY_REQUIREMENTS_INFO_2`

  - `VK_STRUCTURE_TYPE_IMAGE_SPARSE_MEMORY_REQUIREMENTS_INFO_2`

  - `VK_STRUCTURE_TYPE_MEMORY_REQUIREMENTS_2`

  - `VK_STRUCTURE_TYPE_SPARSE_IMAGE_MEMORY_REQUIREMENTS_2`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FEATURES_2`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROPERTIES_2`

  - `VK_STRUCTURE_TYPE_FORMAT_PROPERTIES_2`

  - `VK_STRUCTURE_TYPE_IMAGE_FORMAT_PROPERTIES_2`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGE_FORMAT_INFO_2`

  - `VK_STRUCTURE_TYPE_QUEUE_FAMILY_PROPERTIES_2`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_PROPERTIES_2`

  - `VK_STRUCTURE_TYPE_SPARSE_IMAGE_FORMAT_PROPERTIES_2`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SPARSE_IMAGE_FORMAT_INFO_2`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_POINT_CLIPPING_PROPERTIES`

  - `VK_STRUCTURE_TYPE_RENDER_PASS_INPUT_ATTACHMENT_ASPECT_CREATE_INFO`

  - `VK_STRUCTURE_TYPE_IMAGE_VIEW_USAGE_CREATE_INFO`

  - `VK_STRUCTURE_TYPE_PIPELINE_TESSELLATION_DOMAIN_ORIGIN_STATE_CREATE_INFO`

  - `VK_STRUCTURE_TYPE_RENDER_PASS_MULTIVIEW_CREATE_INFO`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_FEATURES`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_PROPERTIES`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VARIABLE_POINTERS_FEATURES`

  - `VK_STRUCTURE_TYPE_PROTECTED_SUBMIT_INFO`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROTECTED_MEMORY_FEATURES`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROTECTED_MEMORY_PROPERTIES`

  - `VK_STRUCTURE_TYPE_DEVICE_QUEUE_INFO_2`

  - `VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_CREATE_INFO`

  - `VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_INFO`

  - `VK_STRUCTURE_TYPE_BIND_IMAGE_PLANE_MEMORY_INFO`

  - `VK_STRUCTURE_TYPE_IMAGE_PLANE_MEMORY_REQUIREMENTS_INFO`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SAMPLER_YCBCR_CONVERSION_FEATURES`

  - `VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_IMAGE_FORMAT_PROPERTIES`

  - `VK_STRUCTURE_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_CREATE_INFO`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_IMAGE_FORMAT_INFO`

  - `VK_STRUCTURE_TYPE_EXTERNAL_IMAGE_FORMAT_PROPERTIES`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_BUFFER_INFO`

  - `VK_STRUCTURE_TYPE_EXTERNAL_BUFFER_PROPERTIES`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_ID_PROPERTIES`

  - `VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_BUFFER_CREATE_INFO`

  - `VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_IMAGE_CREATE_INFO`

  - `VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_FENCE_INFO`

  - `VK_STRUCTURE_TYPE_EXTERNAL_FENCE_PROPERTIES`

  - `VK_STRUCTURE_TYPE_EXPORT_FENCE_CREATE_INFO`

  - `VK_STRUCTURE_TYPE_EXPORT_SEMAPHORE_CREATE_INFO`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_SEMAPHORE_INFO`

  - `VK_STRUCTURE_TYPE_EXTERNAL_SEMAPHORE_PROPERTIES`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MAINTENANCE_3_PROPERTIES`

  - `VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_SUPPORT`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_DRAW_PARAMETERS_FEATURES`

#### New Enums

- VkChromaLocation

- VkDescriptorUpdateTemplateType

- VkExternalFenceFeatureFlagBits

- VkExternalFenceHandleTypeFlagBits

- VkExternalMemoryFeatureFlagBits

- VkExternalMemoryHandleTypeFlagBits

- VkExternalSemaphoreFeatureFlagBits

- VkExternalSemaphoreHandleTypeFlagBits

- VkFenceImportFlagBits

- VkMemoryAllocateFlagBits

- VkPeerMemoryFeatureFlagBits

- VkPointClippingBehavior

- VkSamplerYcbcrModelConversion

- VkSamplerYcbcrRange

- VkSemaphoreImportFlagBits

- VkSubgroupFeatureFlagBits

- VkTessellationDomainOrigin

- VkCommandPoolTrimFlags

- VkDescriptorUpdateTemplateCreateFlags

- VkExternalFenceFeatureFlags

- VkExternalFenceHandleTypeFlags

- VkExternalMemoryFeatureFlags

- VkExternalMemoryHandleTypeFlags

- VkExternalSemaphoreFeatureFlags

- VkExternalSemaphoreHandleTypeFlags

- VkFenceImportFlags

- VkMemoryAllocateFlags

- VkPeerMemoryFeatureFlags

- VkSemaphoreImportFlags

- VkSubgroupFeatureFlags

#### New Structures

- VkBindBufferMemoryDeviceGroupInfo

- VkBindBufferMemoryInfo

- VkBindImageMemoryDeviceGroupInfo

- VkBindImageMemoryInfo

- VkBindImagePlaneMemoryInfo

- VkBufferMemoryRequirementsInfo2

- VkDescriptorSetLayoutSupport

- VkDescriptorUpdateTemplateCreateInfo

- VkDescriptorUpdateTemplateEntry

- VkDeviceGroupBindSparseInfo

- VkDeviceGroupCommandBufferBeginInfo

- VkDeviceGroupDeviceCreateInfo

- VkDeviceGroupRenderPassBeginInfo

- VkDeviceGroupSubmitInfo

- VkDeviceQueueInfo2

- VkExportFenceCreateInfo

- VkExportMemoryAllocateInfo

- VkExportSemaphoreCreateInfo

- VkExternalBufferProperties

- VkExternalFenceProperties

- VkExternalImageFormatProperties

- VkExternalMemoryBufferCreateInfo

- VkExternalMemoryImageCreateInfo

- VkExternalMemoryProperties

- VkExternalSemaphoreProperties

- VkFormatProperties2

- VkImageFormatProperties2

- VkImageMemoryRequirementsInfo2

- VkImagePlaneMemoryRequirementsInfo

- VkImageSparseMemoryRequirementsInfo2

- VkImageViewUsageCreateInfo

- VkInputAttachmentAspectReference

- VkMemoryAllocateFlagsInfo

- VkMemoryDedicatedAllocateInfo

- VkMemoryDedicatedRequirements

- VkMemoryRequirements2

- VkPhysicalDevice16BitStorageFeatures

- VkPhysicalDeviceExternalBufferInfo

- VkPhysicalDeviceExternalFenceInfo

- VkPhysicalDeviceExternalImageFormatInfo

- VkPhysicalDeviceExternalSemaphoreInfo

- VkPhysicalDeviceFeatures2

- VkPhysicalDeviceGroupProperties

- VkPhysicalDeviceIDProperties

- VkPhysicalDeviceImageFormatInfo2

- VkPhysicalDeviceMaintenance3Properties

- VkPhysicalDeviceMemoryProperties2

- VkPhysicalDeviceMultiviewFeatures

- VkPhysicalDeviceMultiviewProperties

- VkPhysicalDevicePointClippingProperties

- VkPhysicalDeviceProperties2

- VkPhysicalDeviceProtectedMemoryFeatures

- VkPhysicalDeviceProtectedMemoryProperties

- VkPhysicalDeviceSamplerYcbcrConversionFeatures

- VkPhysicalDeviceShaderDrawParametersFeatures

- VkPhysicalDeviceSparseImageFormatInfo2

- VkPhysicalDeviceSubgroupProperties

- VkPhysicalDeviceVariablePointersFeatures

- VkPipelineTessellationDomainOriginStateCreateInfo

- VkProtectedSubmitInfo

- VkQueueFamilyProperties2

- VkRenderPassInputAttachmentAspectCreateInfo

- VkRenderPassMultiviewCreateInfo

- VkSamplerYcbcrConversionCreateInfo

- VkSamplerYcbcrConversionImageFormatProperties

- VkSamplerYcbcrConversionInfo

- VkSparseImageFormatProperties2

- VkSparseImageMemoryRequirements2

#### New Functions

- vkBindBufferMemory2

- vkBindImageMemory2

- vkCmdDispatchBase

- vkCmdSetDeviceMask

- vkCreateDescriptorUpdateTemplate

- vkCreateSamplerYcbcrConversion

- vkDestroyDescriptorUpdateTemplate

- vkDestroySamplerYcbcrConversion

- vkEnumerateInstanceVersion

- vkEnumeratePhysicalDeviceGroups

- vkGetBufferMemoryRequirements2

- vkGetDescriptorSetLayoutSupport

- vkGetDeviceGroupPeerMemoryFeatures

- vkGetDeviceQueue2

- vkGetImageMemoryRequirements2

- vkGetImageSparseMemoryRequirements2

- vkGetPhysicalDeviceExternalBufferProperties

- vkGetPhysicalDeviceExternalFenceProperties

- vkGetPhysicalDeviceExternalSemaphoreProperties

- vkGetPhysicalDeviceFeatures2

- vkGetPhysicalDeviceFormatProperties2

- vkGetPhysicalDeviceImageFormatProperties2

- vkGetPhysicalDeviceMemoryProperties2

- vkGetPhysicalDeviceProperties2

- vkGetPhysicalDeviceQueueFamilyProperties2

- vkGetPhysicalDeviceSparseImageFormatProperties2

- vkTrimCommandPool

- vkUpdateDescriptorSetWithTemplate

## Appendix E: Layers & Extensions (Informative)

Extensions to the Vulkan API can be defined by authors, groups of authors, and the Khronos Vulkan Working Group. In order not to compromise the readability of the Vulkan Specification, the core Specification does not incorporate most extensions. The online Registry of extensions is available at URL

https://www.khronos.org/registry/vulkan/

and allows generating versions of the Specification incorporating different extensions.

Most of the content previously in this appendix does not specify use of specific Vulkan extensions and layers, but rather specifies the processes by which extensions and layers are created. As of version 1.0.21 of the Vulkan Specification, this content has been migrated to the Vulkan Documentation and Extensions document. Authors creating extensions and layers must follow the mandatory procedures in that document.

The remainder of this appendix documents a set of extensions chosen when this document was built. Versions of the Specification published in the Registry include:

- Core API + mandatory extensions required of all Vulkan implementations.

- Core API + all registered and published Khronos (`KHR`) extensions.

- Core API + all registered and published extensions.

Extensions are grouped as Khronos `KHR`, multivendor `EXT`, and then alphabetically by author ID. Within each group, extensions are listed in alphabetical order by their name.

| Note As of the initial Vulkan 1.1 public release, the `KHX` author ID is no longer used. All `KHX` extensions have been promoted to `KHR` status. Previously, this author ID was used to indicate that an extension was experimental, and is being considered for standardization in future `KHR` or core Vulkan API versions. We no longer use this mechanism for exposing experimental functionality. Some vendors may use an alternate author ID ending in `X` for some of their extensions. The exact meaning of such an author ID is defined by each vendor, and may not be equivalent to `KHX`, but it is likely to indicate a lesser degree of interface stability than a non-`X` extension from the same vendor.

### List of Current Extensions

- `VK_KHR_android_surface`

- `VK_KHR_display`

- `VK_KHR_display_swapchain`

- `VK_KHR_external_fence_fd`

- `VK_KHR_external_fence_win32`

- `VK_KHR_external_memory_fd`

- `VK_KHR_external_memory_win32`

- `VK_KHR_external_semaphore_fd`

- `VK_KHR_external_semaphore_win32`

- `VK_KHR_get_display_properties2`

- `VK_KHR_get_surface_capabilities2`

- `VK_KHR_incremental_present`

- `VK_KHR_performance_query`

- `VK_KHR_pipeline_executable_properties`

- `VK_KHR_push_descriptor`

- `VK_KHR_shader_clock`

- `VK_KHR_shader_non_semantic_info`

- `VK_KHR_shared_presentable_image`

- `VK_KHR_surface`

- `VK_KHR_surface_protected_capabilities`

- `VK_KHR_swapchain`

- `VK_KHR_swapchain_mutable_format`

- `VK_KHR_wayland_surface`

- `VK_KHR_win32_keyed_mutex`

- `VK_KHR_win32_surface`

- `VK_KHR_xcb_surface`

- `VK_KHR_xlib_surface`

- `VK_EXT_acquire_xlib_display`

- `VK_EXT_astc_decode_mode`

- `VK_EXT_blend_operation_advanced`

- `VK_EXT_calibrated_timestamps`

- `VK_EXT_conditional_rendering`

- `VK_EXT_conservative_rasterization`

- `VK_EXT_debug_utils`

- `VK_EXT_depth_clip_enable`

- `VK_EXT_depth_range_unrestricted`

- `VK_EXT_direct_mode_display`

- `VK_EXT_discard_rectangles`

- `VK_EXT_display_control`

- `VK_EXT_display_surface_counter`

- `VK_EXT_external_memory_dma_buf`

- `VK_EXT_external_memory_host`

- `VK_EXT_filter_cubic`

- `VK_EXT_fragment_density_map`

- `VK_EXT_fragment_shader_interlock`

- `VK_EXT_full_screen_exclusive`

- `VK_EXT_global_priority`

- `VK_EXT_hdr_metadata`

- `VK_EXT_headless_surface`

- `VK_EXT_image_drm_format_modifier`

- `VK_EXT_index_type_uint8`

- `VK_EXT_inline_uniform_block`

- `VK_EXT_line_rasterization`

- `VK_EXT_memory_budget`

- `VK_EXT_memory_priority`

- `VK_EXT_metal_surface`

- `VK_EXT_pci_bus_info`

- `VK_EXT_pipeline_creation_cache_control`

- `VK_EXT_pipeline_creation_feedback`

- `VK_EXT_post_depth_coverage`

- `VK_EXT_queue_family_foreign`

- `VK_EXT_sample_locations`

- `VK_EXT_shader_demote_to_helper_invocation`

- `VK_EXT_shader_stencil_export`

- `VK_EXT_subgroup_size_control`

- `VK_EXT_swapchain_colorspace`

- `VK_EXT_texel_buffer_alignment`

- `VK_EXT_texture_compression_astc_hdr`

- `VK_EXT_tooling_info`

- `VK_EXT_transform_feedback`

- `VK_EXT_validation_cache`

- `VK_EXT_validation_features`

- `VK_EXT_vertex_attribute_divisor`

- `VK_EXT_ycbcr_image_arrays`

- `VK_AMD_buffer_marker`

- `VK_AMD_device_coherent_memory`

- `VK_AMD_display_native_hdr`

- `VK_AMD_gcn_shader`

- `VK_AMD_memory_overallocation_behavior`

- `VK_AMD_mixed_attachment_samples`

- `VK_AMD_pipeline_compiler_control`

- `VK_AMD_rasterization_order`

- `VK_AMD_shader_ballot`

- `VK_AMD_shader_core_properties`

- `VK_AMD_shader_core_properties2`

- `VK_AMD_shader_explicit_vertex_parameter`

- `VK_AMD_shader_fragment_mask`

- `VK_AMD_shader_image_load_store_lod`

- `VK_AMD_shader_info`

- `VK_AMD_shader_trinary_minmax`

- `VK_AMD_texture_gather_bias_lod`

- `VK_ANDROID_external_memory_android_hardware_buffer`

- `VK_FUCHSIA_imagepipe_surface`

- `VK_GGP_frame_token`

- `VK_GGP_stream_descriptor_surface`

- `VK_GOOGLE_decorate_string`

- `VK_GOOGLE_display_timing`

- `VK_GOOGLE_hlsl_functionality1`

- `VK_GOOGLE_user_type`

- `VK_IMG_filter_cubic`

- `VK_IMG_format_pvrtc`

- `VK_INTEL_performance_query`

- `VK_INTEL_shader_integer_functions2`

- `VK_MVK_ios_surface`

- `VK_MVK_macos_surface`

- `VK_NN_vi_surface`

- `VK_NV_clip_space_w_scaling`

- `VK_NV_compute_shader_derivatives`

- `VK_NV_cooperative_matrix`

- `VK_NV_corner_sampled_image`

- `VK_NV_coverage_reduction_mode`

- `VK_NV_dedicated_allocation_image_aliasing`

- `VK_NV_device_diagnostic_checkpoints`

- `VK_NV_device_diagnostics_config`

- `VK_NV_device_generated_commands`

- `VK_NV_fill_rectangle`

- `VK_NV_fragment_coverage_to_color`

- `VK_NV_fragment_shader_barycentric`

- `VK_NV_framebuffer_mixed_samples`

- `VK_NV_geometry_shader_passthrough`

- `VK_NV_mesh_shader`

- `VK_NV_ray_tracing`

- `VK_NV_representative_fragment_test`

- `VK_NV_sample_mask_override_coverage`

- `VK_NV_scissor_exclusive`

- `VK_NV_shader_image_footprint`

- `VK_NV_shader_sm_builtins`

- `VK_NV_shader_subgroup_partitioned`

- `VK_NV_shading_rate_image`

- `VK_NV_viewport_array2`

- `VK_NV_viewport_swizzle`

- `VK_NVX_image_view_handle`

- `VK_NVX_multiview_per_view_attributes`

- `VK_QCOM_render_pass_transform`

#### VK_KHR_android_surface

Name String

  `VK_KHR_android_surface`

Extension Type

  Instance extension

Registered Extension Number

  9

Revision

  6

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_surface`

Contact

  - Jesse Hall critsec

Last Modified Date

  2016-01-14

IP Status

  No known IP claims.

Contributors

  - Patrick Doane, Blizzard

  - Jason Ekstrand, Intel

  - Ian Elliott, LunarG

  - Courtney Goeltzenleuchter, LunarG

  - Jesse Hall, Google

  - James Jones, NVIDIA

  - Antoine Labour, Google

  - Jon Leech, Khronos

  - David Mao, AMD

  - Norbert Nopper, Freescale

  - Alon Or-bach, Samsung

  - Daniel Rakos, AMD

  - Graham Sellers, AMD

  - Ray Smith, ARM

  - Jeff Vigil, Qualcomm

  - Chia-I Wu, LunarG

The `VK_KHR_android_surface` extension is an instance extension. It provides a mechanism to create a VkSurfaceKHR object (defined by the `VK_KHR_surface` extension) that refers to an ANativeWindow, Android’s native surface type. The ANativeWindow represents the producer endpoint of any buffer queue, regardless of consumer endpoint. Common consumer endpoints for `ANativeWindows` are the system window compositor, video encoders, and application-specific compositors importing the images through a `SurfaceTexture`.

#### New Object Types

None

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_ANDROID_SURFACE_CREATE_INFO_KHR`

#### New Enums

None

#### New Structures

- VkAndroidSurfaceCreateInfoKHR

#### New Functions

- vkCreateAndroidSurfaceKHR

#### Issues

1) Does Android need a way to query for compatibility between a particular physical device (and queue family?) and a specific Android display?

RESOLVED: No. Currently on Android, any physical device is expected to be able to present to the system compositor, and all queue families must support the necessary image layout transitions and synchronization operations.

#### Version History

- Revision 1, 2015-09-23 (Jesse Hall)

  - Initial draft.

- Revision 2, 2015-10-26 (Ian Elliott)

  - Renamed from VK_EXT_KHR_android_surface to VK_KHR_android_surface.

- Revision 3, 2015-11-03 (Daniel Rakos)

  - Added allocation callbacks to surface creation function.

- Revision 4, 2015-11-10 (Jesse Hall)

  - Removed VK_ERROR_INVALID_ANDROID_WINDOW_KHR.

- Revision 5, 2015-11-28 (Daniel Rakos)

  - Updated the surface create function to take a pCreateInfo structure.

- Revision 6, 2016-01-14 (James Jones)

  - Moved VK_ERROR_NATIVE_WINDOW_IN_USE_KHR from the VK_KHR_android_surface to the VK_KHR_surface extension.

#### VK_KHR_display

Name String

  `VK_KHR_display`

Extension Type

  Instance extension

Registered Extension Number

  3

Revision

  23

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_surface`

Contact

  - James Jones cubanismo

  - Norbert Nopper FslNopper

Last Modified Date

  2017-03-13

IP Status

  No known IP claims.

Contributors

  - James Jones, NVIDIA

  - Norbert Nopper, Freescale

  - Jeff Vigil, Qualcomm

  - Daniel Rakos, AMD

This extension provides the API to enumerate displays and available modes on a given device.

#### New Object Types

- VkDisplayKHR

- VkDisplayModeKHR

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_DISPLAY_MODE_CREATE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_DISPLAY_SURFACE_CREATE_INFO_KHR`

#### New Enums

- VkDisplayPlaneAlphaFlagBitsKHR

#### New Structures

- VkDisplayPropertiesKHR

- VkDisplayModeParametersKHR

- VkDisplayModePropertiesKHR

- VkDisplayModeCreateInfoKHR

- VkDisplayPlanePropertiesKHR

- VkDisplayPlaneCapabilitiesKHR

- VkDisplaySurfaceCreateInfoKHR

#### New Functions

- vkGetPhysicalDeviceDisplayPropertiesKHR

- vkGetPhysicalDeviceDisplayPlanePropertiesKHR

- vkGetDisplayPlaneSupportedDisplaysKHR

- vkGetDisplayModePropertiesKHR

- vkCreateDisplayModeKHR

- vkGetDisplayPlaneCapabilitiesKHR

- vkCreateDisplayPlaneSurfaceKHR

#### Issues

1) Which properties of a mode should be fixed in the mode info vs. settable in some other function when setting the mode? E.g., do we need to double the size of the mode pool to include both stereo and non-stereo modes? YUV and RGB scanout even if they both take RGB input images? BGR vs. RGB input? etc.

PROPOSED RESOLUTION: Many modern displays support at most a handful of resolutions and timings natively. Other “modes” are expected to be supported using scaling hardware on the display engine or GPU. Other properties, such as rotation and mirroring should not require duplicating hardware modes just to express all combinations. Further, these properties may be implemented on a per-display or per-overlay granularity.

To avoid the exponential growth of modes as mutable properties are added, as was the case with `EGLConfig`/WGL pixel formats/`GLXFBConfig`, this specification should separate out hardware properties and configurable state into separate objects. Modes and overlay planes will express capabilities of the hardware, while a separate structure will allow applications to configure scaling, rotation, mirroring, color keys, LUT values, alpha masks, etc. for a given swapchain independent of the mode in use. Constraints on these settings will be established by properties of the immutable objects.

Note the resolution of this issue may affect issue 5 as well.

2) What properties of a display itself are useful?

PROPOSED RESOLUTION: This issue is too broad. It was meant to prompt general discussion, but resolving this issue amounts to completing this specification. All interesting properties should be included. The issue will remain as a placeholder since removing it would make it hard to parse existing discussion notes that refer to issues by number.

3) How are multiple overlay planes within a display or mode enumerated?

PROPOSED RESOLUTION: They are referred to by an index. Each display will report the number of overlay planes it contains.

4) Should swapchains be created relative to a mode or a display?

PROPOSED RESOLUTION: When using this extension, swapchains are created relative to a mode and a plane. The mode implies the display object the swapchain will present to. If the specified mode is not the display’s current mode, the new mode will be applied when the first image is presented to the swapchain, and the default operating system mode, if any, will be restored when the swapchain is destroyed.

5) Should users query generic ranges from displays and construct their own modes explicitly using those constraints rather than querying a fixed set of modes (Most monitors only have one real “mode” these days, even though many support relatively arbitrary scaling, either on the monitor side or in the GPU display engine, making “modes” something of a relic/compatibility construct).

PROPOSED RESOLUTION: Expose both. Display info structures will expose a set of predefined modes, as well as any attributes necessary to construct a customized mode.

6) Is it fine if we return the display and display mode handles in the structure used to query their properties?

PROPOSED RESOLUTION: Yes.

7) Is there a possibility that not all displays of a device work with all of the present queues of a device? If yes, how do we determine which displays work with which present queues?

PROPOSED RESOLUTION: No known hardware has such limitations, but determining such limitations is supported automatically using the existing `VK_KHR_surface` and `VK_KHR_swapchain` query mechanisms.

8) Should all presentation need to be done relative to an overlay plane, or can a display mode + display be used alone to target an output?

PROPOSED RESOLUTION: Require specifying a plane explicitly.

9) Should displays have an associated window system display, such as an `HDC` or `Display`*?

PROPOSED RESOLUTION: No. Displays are independent of any windowing system in use on the system. Further, neither `HDC` nor `Display`* refer to a physical display object.

10) Are displays queried from a physical GPU or from a device instance?

PROPOSED RESOLUTION: Developers prefer to query modes directly from the physical GPU so they can use display information as an input to their device selection algorithms prior to device creation. This avoids the need to create dummy device instances to enumerate displays.

This preference must be weighed against the extra initialization that must be done by driver vendors prior to device instance creation to support this usage.

11) Should displays and/or modes be dispatchable objects? If functions are to take displays, overlays, or modes as their first parameter, they must be dispatchable objects as defined in Khronos bug 13529. If they are not added to the list of dispatchable objects, functions operating on them must take some higher-level object as their first parameter. There is no performance case against making them dispatchable objects, but they would be the first extension objects to be dispatchable.

PROPOSED RESOLUTION: Do not make displays or modes dispatchable. They will dispatch based on their associated physical device.

12) Should hardware cursor capabilities be exposed?

PROPOSED RESOLUTION: Defer. This could be a separate extension on top of the base WSI specs.

| editing-note There appears to be a missing sentence for the first part of issue 13 here.

if they are one physical display device to an end user, but may internally be implemented as two side-by-side displays using the same display engine (and sometimes cabling) resources as two physically separate display devices.

RESOLVED: Tiled displays will appear as a single display object in this API.

14) Should the raw EDID data be included in the display information?

RESOLVED: No. A future extension could be added which reports the EDID if necessary. This may be complicated by the outcome of issue 13.

15) Should min and max scaling factor capabilities of overlays be exposed?

RESOLVED: Yes. This is exposed indirectly by allowing applications to query the min/max position and extent of the source and destination regions from which image contents are fetched by the display engine when using a particular mode and overlay pair.

16) Should devices be able to expose planes that can be moved between displays? If so, how?

RESOLVED: Yes. Applications can determine which displays a given plane supports using vkGetDisplayPlaneSupportedDisplaysKHR.

17) Should there be a way to destroy display modes? If so, does it support destroying “built in” modes?

RESOLVED: Not in this extension. A future extension could add this functionality.

18) What should the lifetime of display and built-in display mode objects be?

RESOLVED: The lifetime of the instance. These objects cannot be destroyed. A future extension may be added to expose a way to destroy these objects and/or support display hotplug.

19) Should persistent mode for smart panels be enabled/disabled at swapchain creation time, or on a per-present basis.

RESOLVED: On a per-present basis.

#### Examples

| Note The example code for the `VK_KHR_display` and `VK_KHR_display_swapchain` extensions was removed from the appendix after revision 1.0.43. The display enumeration example code was ported to the cube demo that is shipped with the official Khronos SDK, and is being kept up-to-date in that location (see: https://github.com/KhronosGroup/Vulkan-Tools/blob/master/cube/cube.c).

#### Version History

- Revision 1, 2015-02-24 (James Jones)

  - Initial draft

- Revision 2, 2015-03-12 (Norbert Nopper)

  - Added overlay enumeration for a display.

- Revision 3, 2015-03-17 (Norbert Nopper)

  - Fixed typos and namings as discussed in Bugzilla.

  - Reordered and grouped functions.

  - Added functions to query count of display, mode and overlay.

  - Added native display handle, which is maybe needed on some platforms to create a native Window.

- Revision 4, 2015-03-18 (Norbert Nopper)

  - Removed primary and virtualPostion members (see comment of James Jones in Bugzilla).

  - Added native overlay handle to info structure.

  - Replaced , with ; in struct.

- Revision 6, 2015-03-18 (Daniel Rakos)

  - Added WSI extension suffix to all items.

  - Made the whole API more "Vulkanish".

  - Replaced all functions with a single vkGetDisplayInfoKHR function to better match the rest of the API.

  - Made the display, display mode, and overlay objects be first class objects, not subclasses of VkBaseObject as they do not support the common functions anyways.

  - Renamed *Info structures to *Properties.

  - Removed overlayIndex field from VkOverlayProperties as there is an implicit index already as a result of moving to a "Vulkanish" API.

  - Displays are not get through device, but through physical GPU to match the rest of the Vulkan API. Also this is something ISVs explicitly requested.

  - Added issue (6) and (7).

- Revision 7, 2015-03-25 (James Jones)

  - Added an issues section

  - Added rotation and mirroring flags

- Revision 8, 2015-03-25 (James Jones)

  - Combined the duplicate issues sections introduced in last change.

  - Added proposed resolutions to several issues.

- Revision 9, 2015-04-01 (Daniel Rakos)

  - Rebased extension against Vulkan 0.82.0

- Revision 10, 2015-04-01 (James Jones)

  - Added issues (10) and (11).

  - Added more straw-man issue resolutions, and cleaned up the proposed resolution for issue (4).

  - Updated the rotation and mirroring enums to have proper bitmask semantics.

- Revision 11, 2015-04-15 (James Jones)

  - Added proposed resolution for issues (1) and (2).

  - Added issues (12), (13), (14), and (15)

  - Removed pNativeHandle field from overlay structure.

  - Fixed small compilation errors in example code.

- Revision 12, 2015-07-29 (James Jones)

  - Rewrote the guts of the extension against the latest WSI swapchain specifications and the latest Vulkan API.

  - Address overlay planes by their index rather than an object handle and refer to them as "planes" rather than "overlays" to make it slightly clearer that even a display with no "overlays" still has at least one base "plane" that images can be displayed on.

  - Updated most of the issues.

  - Added an "extension type" section to the specification header.

  - Re-used the VK_EXT_KHR_surface surface transform enumerations rather than redefining them here.

  - Updated the example code to use the new semantics.

- Revision 13, 2015-08-21 (Ian Elliott)

  - Renamed this extension and all of its enumerations, types, functions, etc. This makes it compliant with the proposed standard for Vulkan extensions.

  - Switched from "revision" to "version", including use of the VK_MAKE_VERSION macro in the header file.

- Revision 14, 2015-09-01 (James Jones)

  - Restore single-field revision number.

- Revision 15, 2015-09-08 (James Jones)

  - Added alpha flags enum.

  - Added premultiplied alpha support.

- Revision 16, 2015-09-08 (James Jones)

  - Added description section to the spec.

  - Added issues 16 - 18.

- Revision 17, 2015-10-02 (James Jones)

  - Planes are now a property of the entire device rather than individual displays. This allows planes to be moved between multiple displays on devices that support it.

  - Added a function to create a VkSurfaceKHR object describing a display plane and mode to align with the new per-platform surface creation conventions.

  - Removed detailed mode timing data. It was agreed that the mode extents and refresh rate are sufficient for current use cases. Other information could be added back2 in as an extension if it is needed in the future.

  - Added support for smart/persistent/buffered display devices.

- Revision 18, 2015-10-26 (Ian Elliott)

  - Renamed from VK_EXT_KHR_display to VK_KHR_display.

- Revision 19, 2015-11-02 (James Jones)

  - Updated example code to match revision 17 changes.

- Revision 20, 2015-11-03 (Daniel Rakos)

  - Added allocation callbacks to creation functions.

- Revision 21, 2015-11-10 (Jesse Hall)

  - Added VK_DISPLAY_PLANE_ALPHA_OPAQUE_BIT_KHR, and use VkDisplayPlaneAlphaFlagBitsKHR for VkDisplayPlanePropertiesKHR::alphaMode instead of VkDisplayPlaneAlphaFlagsKHR, since it only represents one mode.

  - Added reserved flags bitmask to VkDisplayPlanePropertiesKHR.

  - Use VkSurfaceTransformFlagBitsKHR instead of obsolete VkSurfaceTransformKHR.

  - Renamed vkGetDisplayPlaneSupportedDisplaysKHR parameters for clarity.

- Revision 22, 2015-12-18 (James Jones)

  - Added missing "planeIndex" parameter to vkGetDisplayPlaneSupportedDisplaysKHR()

- Revision 23, 2017-03-13 (James Jones)

  - Closed all remaining issues. The specification and implementations have been shipping with the proposed resolutions for some time now.

  - Removed the sample code and noted it has been integrated into the official Vulkan SDK cube demo.

#### VK_KHR_display_swapchain

Name String

  `VK_KHR_display_swapchain`

Extension Type

  Device extension

Registered Extension Number

  4

Revision

  10

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_swapchain`

  - Requires `VK_KHR_display`

Contact

  - James Jones cubanismo

Last Modified Date

  2017-03-13

IP Status

  No known IP claims.

Contributors

  - James Jones, NVIDIA

  - Jeff Vigil, Qualcomm

  - Jesse Hall, Google

This extension provides an API to create a swapchain directly on a device’s display without any underlying window system.

#### New Object Types

None

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_DISPLAY_PRESENT_INFO_KHR`

- Extending VkResult:

  - `VK_ERROR_INCOMPATIBLE_DISPLAY_KHR`

#### New Enums

None

#### New Structures

- VkDisplayPresentInfoKHR

#### New Functions

- vkCreateSharedSwapchainsKHR

#### Issues

1) Should swapchains sharing images each hold a reference to the images, or should it be up to the application to destroy the swapchains and images in an order that avoids the need for reference counting?

RESOLVED: Take a reference. The lifetime of presentable images is already complex enough.

2) Should the `srcRect` and `dstRect` parameters be specified as part of the present command, or at swapchain creation time?

RESOLVED: As part of the presentation command. This allows moving and scaling the image on the screen without the need to respecify the mode or create a new swapchain and presentable images.

3) Should `srcRect` and `dstRect` be specified as rects, or separate offset/extent values?

RESOLVED: As rects. Specifying them separately might make it easier for hardware to expose support for one but not the other, but in such cases applications must just take care to obey the reported capabilities and not use non-zero offsets or extents that require scaling, as appropriate.

4) How can applications create multiple swapchains that use the same images?

RESOLVED: By calling vkCreateSharedSwapchainsKHR.

An earlier resolution used vkCreateSwapchainKHR, chaining multiple VkSwapchainCreateInfoKHR structures through `pNext`. In order to allow each swapchain to also allow other extension structs, a level of indirection was used: VkSwapchainCreateInfoKHR::`pNext` pointed to a different structure, which had both `sType` and `pNext` members for additional extensions, and also had a pointer to the next VkSwapchainCreateInfoKHR structure. The number of swapchains to be created could only be found by walking this linked list of alternating structures, and the `pSwapchains` out parameter was reinterpreted to be an array of VkSwapchainKHR handles.

Another option considered was a method to specify a “shared” swapchain when creating a new swapchain, such that groups of swapchains using the same images could be built up one at a time. This was deemed unusable because drivers need to know all of the displays an image will be used on when determining which internal formats and layouts to use for that image.

#### Examples

| Note The example code for the `VK_KHR_display` and `VK_KHR_display_swapchain` extensions was removed from the appendix after revision 1.0.43. The display swapchain creation example code was ported to the cube demo that is shipped with the official Khronos SDK, and is being kept up-to-date in that location (see: https://github.com/KhronosGroup/Vulkan-Tools/blob/master/cube/cube.c).

#### Version History

- Revision 1, 2015-07-29 (James Jones)

  - Initial draft

- Revision 2, 2015-08-21 (Ian Elliott)

  - Renamed this extension and all of its enumerations, types, functions, etc. This makes it compliant with the proposed standard for Vulkan extensions.

  - Switched from "revision" to "version", including use of the VK_MAKE_VERSION macro in the header file.

- Revision 3, 2015-09-01 (James Jones)

  - Restore single-field revision number.

- Revision 4, 2015-09-08 (James Jones)

  - Allow creating multiple swap chains that share the same images using a single call to vkCreateSwapChainKHR().

- Revision 5, 2015-09-10 (Alon Or-bach)

  - Removed underscores from SWAP_CHAIN in two enums.

- Revision 6, 2015-10-02 (James Jones)

  - Added support for smart panels/buffered displays.

- Revision 7, 2015-10-26 (Ian Elliott)

  - Renamed from VK_EXT_KHR_display_swapchain to VK_KHR_display_swapchain.

- Revision 8, 2015-11-03 (Daniel Rakos)

  - Updated sample code based on the changes to VK_KHR_swapchain.

- Revision 9, 2015-11-10 (Jesse Hall)

  - Replaced VkDisplaySwapchainCreateInfoKHR with vkCreateSharedSwapchainsKHR, changing resolution of issue #4.

- Revision 10, 2017-03-13 (James Jones)

  - Closed all remaining issues. The specification and implementations have been shipping with the proposed resolutions for some time now.

  - Removed the sample code and noted it has been integrated into the official Vulkan SDK cube demo.

#### VK_KHR_external_fence_fd

Name String

  `VK_KHR_external_fence_fd`

Extension Type

  Device extension

Registered Extension Number

  116

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_external_fence`

Contact

  - Jesse Hall critsec

Last Modified Date

  2017-05-08

IP Status

  No known IP claims.

Contributors

  - Jesse Hall, Google

  - James Jones, NVIDIA

  - Jeff Juliano, NVIDIA

  - Cass Everitt, Oculus

  - Contributors to `VK_KHR_external_semaphore_fd`

An application using external memory may wish to synchronize access to that memory using fences. This extension enables an application to export fence payload to and import fence payload from POSIX file descriptors.

#### New Object Types

None.

#### New Enum Constants

- `VK_STRUCTURE_TYPE_IMPORT_FENCE_FD_INFO_KHR`

- `VK_STRUCTURE_TYPE_FENCE_GET_FD_INFO_KHR`

#### New Enums

None.

#### New Structs

- VkImportFenceFdInfoKHR

- VkFenceGetFdInfoKHR

#### New Functions

- vkImportFenceFdKHR

- vkGetFenceFdKHR

#### Issues

This extension borrows concepts, semantics, and language from `VK_KHR_external_semaphore_fd`. That extension’s issues apply equally to this extension.

#### Version History

- Revision 1, 2017-05-08 (Jesse Hall)

  - Initial revision

#### VK_KHR_external_fence_win32

Name String

  `VK_KHR_external_fence_win32`

Extension Type

  Device extension

Registered Extension Number

  115

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_external_fence`

Contact

  - Jesse Hall critsec

Last Modified Date

  2017-05-08

IP Status

  No known IP claims.

Contributors

  - Jesse Hall, Google

  - James Jones, NVIDIA

  - Jeff Juliano, NVIDIA

  - Cass Everitt, Oculus

  - Contributors to `VK_KHR_external_semaphore_win32`

An application using external memory may wish to synchronize access to that memory using fences. This extension enables an application to export fence payload to and import fence payload from Windows handles.

#### New Object Types

None.

#### New Enum Constants

- `VK_STRUCTURE_TYPE_IMPORT_FENCE_WIN32_HANDLE_INFO_KHR`

- `VK_STRUCTURE_TYPE_EXPORT_FENCE_WIN32_HANDLE_INFO_KHR`

- `VK_STRUCTURE_TYPE_FENCE_GET_WIN32_HANDLE_INFO_KHR`

#### New Enums

None.

#### New Structs

- VkImportFenceWin32HandleInfoKHR

- VkExportFenceWin32HandleInfoKHR

- VkFenceGetWin32HandleInfoKHR

#### New Functions

- vkImportFenceWin32HandleKHR

- vkGetFenceWin32HandleKHR

#### Issues

This extension borrows concepts, semantics, and language from `VK_KHR_external_semaphore_win32`. That extension’s issues apply equally to this extension.

1) Should D3D12 fence handle types be supported, like they are for semaphores?

RESOLVED: No. Doing so would require extending the fence signal and wait operations to provide values to signal / wait for, like `VkD3D12FenceSubmitInfoKHR` does. A D3D12 fence can be signaled by importing it into a VkSemaphore instead of a VkFence, and applications can check status or wait on the D3D12 fence using non-Vulkan APIs. The convenience of being able to do these operations on `VkFence` objects doesn’t justify the extra API complexity.

#### Version History

- Revision 1, 2017-05-08 (Jesse Hall)

  - Initial revision

#### VK_KHR_external_memory_fd

Name String

  `VK_KHR_external_memory_fd`

Extension Type

  Device extension

Registered Extension Number

  75

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_external_memory`

Contact

  - James Jones cubanismo

Last Modified Date

  2016-10-21

IP Status

  No known IP claims.

Contributors

  - James Jones, NVIDIA

  - Jeff Juliano, NVIDIA

An application may wish to reference device memory in multiple Vulkan logical devices or instances, in multiple processes, and/or in multiple APIs. This extension enables an application to export POSIX file descriptor handles from Vulkan memory objects and to import Vulkan memory objects from POSIX file descriptor handles exported from other Vulkan memory objects or from similar resources in other APIs.

#### New Object Types

None.

#### New Enum Constants

- `VK_STRUCTURE_TYPE_IMPORT_MEMORY_FD_INFO_KHR`

- `VK_STRUCTURE_TYPE_MEMORY_FD_PROPERTIES_KHR`

- `VK_STRUCTURE_TYPE_MEMORY_GET_FD_INFO_KHR`

#### New Enums

None.

#### New Structs

- VkImportMemoryFdInfoKHR

- VkMemoryFdPropertiesKHR

- VkMemoryGetFdInfoKHR

#### New Functions

- vkGetMemoryFdKHR

- vkGetMemoryFdPropertiesKHR

#### Issues

1) Does the application need to close the file descriptor returned by vkGetMemoryFdKHR?

RESOLVED: Yes, unless it is passed back in to a driver instance to import the memory. A successful get call transfers ownership of the file descriptor to the application, and a successful import transfers it back to the driver. Destroying the original memory object will not close the file descriptor or remove its reference to the underlying memory resource associated with it.

2) Do drivers ever need to expose multiple file descriptors per memory object?

RESOLVED: No. This would indicate there are actually multiple memory objects, rather than a single memory object.

3) How should the valid size and memory type for POSIX file descriptor memory handles created outside of Vulkan be specified?

RESOLVED: The valid memory types are queried directly from the external handle. The size will be specified by future extensions that introduce such external memory handle types.

#### Version History

- Revision 1, 2016-10-21 (James Jones)

  - Initial revision

#### VK_KHR_external_memory_win32

Name String

  `VK_KHR_external_memory_win32`

Extension Type

  Device extension

Registered Extension Number

  74

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_external_memory`

Contact

  - James Jones cubanismo

Last Modified Date

  2016-10-21

IP Status

  No known IP claims.

Contributors

  - James Jones, NVIDIA

  - Jeff Juliano, NVIDIA

  - Carsten Rohde, NVIDIA

An application may wish to reference device memory in multiple Vulkan logical devices or instances, in multiple processes, and/or in multiple APIs. This extension enables an application to export Windows handles from Vulkan memory objects and to import Vulkan memory objects from Windows handles exported from other Vulkan memory objects or from similar resources in other APIs.

#### New Object Types

None.

#### New Enum Constants

- `VK_STRUCTURE_TYPE_IMPORT_MEMORY_WIN32_HANDLE_INFO_KHR`

- `VK_STRUCTURE_TYPE_EXPORT_MEMORY_WIN32_HANDLE_INFO_KHR`

- `VK_STRUCTURE_TYPE_MEMORY_WIN32_HANDLE_PROPERTIES_KHR`

- `VK_STRUCTURE_TYPE_MEMORY_GET_WIN32_HANDLE_INFO_KHR`

#### New Enums

None.

#### New Structs

- VkImportMemoryWin32HandleInfoKHR

- VkExportMemoryWin32HandleInfoKHR

- VkMemoryWin32HandlePropertiesKHR

- VkMemoryGetWin32HandleInfoKHR

#### New Functions

- vkGetMemoryWin32HandleKHR

- vkGetMemoryWin32HandlePropertiesKHR

#### Issues

1) Do applications need to call `CloseHandle`() on the values returned from vkGetMemoryWin32HandleKHR when `handleType` is `VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT_KHR`?

| editing-note (Jon) This issue refers to a token from `VK_KHR_external_semaphore_win32`, but there’s no dependency or interaction with that extension defined above.

RESOLVED: Yes, unless it is passed back in to another driver instance to import the object. A successful get call transfers ownership of the handle to the application. Destroying the memory object will not destroy the handle or the handle’s reference to the underlying memory resource.

2) Should the language regarding KMT/Windows 7 handles be moved to a separate extension so that it can be deprecated over time?

RESOLVED: No. Support for them can be deprecated by drivers if they choose, by no longer returning them in the supported handle types of the instance level queries.

3) How should the valid size and memory type for windows memory handles created outside of Vulkan be specified?

RESOLVED: The valid memory types are queried directly from the external handle. The size is determined by the associated image or buffer memory requirements for external handle types that require dedicated allocations, and by the size specified when creating the object from which the handle was exported for other external handle types.

#### Version History

- Revision 1, 2016-10-21 (James Jones)

  - Initial revision

#### VK_KHR_external_semaphore_fd

Name String

  `VK_KHR_external_semaphore_fd`

Extension Type

  Device extension

Registered Extension Number

  80

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_external_semaphore`

Contact

  - James Jones cubanismo

Last Modified Date

  2016-10-21

IP Status

  No known IP claims.

Contributors

  - Jesse Hall, Google

  - James Jones, NVIDIA

  - Jeff Juliano, NVIDIA

  - Carsten Rohde, NVIDIA

An application using external memory may wish to synchronize access to that memory using semaphores. This extension enables an application to export semaphore payload to and import semaphore payload from POSIX file descriptors.

#### New Object Types

None.

#### New Enum Constants

- `VK_STRUCTURE_TYPE_IMPORT_SEMAPHORE_FD_INFO_KHR`

- `VK_STRUCTURE_TYPE_SEMAPHORE_GET_FD_INFO_KHR`

#### New Enums

None.

#### New Structs

- VkImportSemaphoreFdInfoKHR

- VkSemaphoreGetFdInfoKHR

#### New Functions

- vkImportSemaphoreFdKHR

- vkGetSemaphoreFdKHR

#### Issues

1) Does the application need to close the file descriptor returned by vkGetSemaphoreFdKHR?

RESOLVED: Yes, unless it is passed back in to a driver instance to import the semaphore. A successful get call transfers ownership of the file descriptor to the application, and a successful import transfers it back to the driver. Destroying the original semaphore object will not close the file descriptor or remove its reference to the underlying semaphore resource associated with it.

#### Version History

- Revision 1, 2016-10-21 (Jesse Hall)

  - Initial revision

#### VK_KHR_external_semaphore_win32

Name String

  `VK_KHR_external_semaphore_win32`

Extension Type

  Device extension

Registered Extension Number

  79

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_external_semaphore`

Contact

  - James Jones cubanismo

Last Modified Date

  2016-10-21

IP Status

  No known IP claims.

Contributors

  - James Jones, NVIDIA

  - Jeff Juliano, NVIDIA

  - Carsten Rohde, NVIDIA

An application using external memory may wish to synchronize access to that memory using semaphores. This extension enables an application to export semaphore payload to and import semaphore payload from Windows handles.

#### New Object Types

None.

#### New Enum Constants

- `VK_STRUCTURE_TYPE_IMPORT_SEMAPHORE_WIN32_HANDLE_INFO_KHR`

- `VK_STRUCTURE_TYPE_EXPORT_SEMAPHORE_WIN32_HANDLE_INFO_KHR`

- `VK_STRUCTURE_TYPE_D3D12_FENCE_SUBMIT_INFO_KHR`

- `VK_STRUCTURE_TYPE_SEMAPHORE_GET_WIN32_HANDLE_INFO_KHR`

#### New Enums

None.

#### New Structs

- VkImportSemaphoreWin32HandleInfoKHR

- VkExportSemaphoreWin32HandleInfoKHR

- VkD3D12FenceSubmitInfoKHR

- VkSemaphoreGetWin32HandleInfoKHR

#### New Functions

- vkImportSemaphoreWin32HandleKHR

- vkGetSemaphoreWin32HandleKHR

#### Issues

1) Do applications need to call `CloseHandle`() on the values returned from vkGetSemaphoreWin32HandleKHR when `handleType` is `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_BIT_KHR`?

RESOLVED: Yes, unless it is passed back in to another driver instance to import the object. A successful get call transfers ownership of the handle to the application. Destroying the semaphore object will not destroy the handle or the handle’s reference to the underlying semaphore resource.

2) Should the language regarding KMT/Windows 7 handles be moved to a separate extension so that it can be deprecated over time?

RESOLVED: No. Support for them can be deprecated by drivers if they choose, by no longer returning them in the supported handle types of the instance level queries.

3) Should applications be allowed to specify additional object attributes for shared handles?

RESOLVED: Yes. Applications will be allowed to provide similar attributes to those they would to any other handle creation API.

4) How do applications communicate the desired fence values to use with `D3D12_FENCE`-based Vulkan semaphores?

RESOLVED: There are a couple of options. The values for the signaled and reset states could be communicated up front when creating the object and remain static for the life of the Vulkan semaphore, or they could be specified using auxiliary structures when submitting semaphore signal and wait operations, similar to what is done with the keyed mutex extensions. The latter is more flexible and consistent with the keyed mutex usage, but the former is a much simpler API.

Since Vulkan tends to favor flexibility and consistency over simplicity, a new structure specifying D3D12 fence acquire and release values is added to the vkQueueSubmit function.

#### Version History

- Revision 1, 2016-10-21 (James Jones)

  - Initial revision

#### VK_KHR_get_display_properties2

Name String

  `VK_KHR_get_display_properties2`

Extension Type

  Instance extension

Registered Extension Number

  122

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_display`

Contact

  - James Jones cubanismo

Last Modified Date

  2017-02-21

IP Status

  No known IP claims.

Contributors

  - Ian Elliott, Google

  - James Jones, NVIDIA

This extension provides new entry points to query device display properties and capabilities in a way that can be easily extended by other extensions, without introducing any further entry points. This extension can be considered the `VK_KHR_display` equivalent of the `VK_KHR_get_physical_device_properties2` extension.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_DISPLAY_PROPERTIES_2_KHR`

  - `VK_STRUCTURE_TYPE_DISPLAY_PLANE_PROPERTIES_2_KHR`

  - `VK_STRUCTURE_TYPE_DISPLAY_MODE_PROPERTIES_2_KHR`

  - `VK_STRUCTURE_TYPE_DISPLAY_PLANE_INFO_2_KHR`

  - `VK_STRUCTURE_TYPE_DISPLAY_PLANE_CAPABILITIES_2_KHR`

#### New Enums

None.

#### New Structures

- VkDisplayProperties2KHR

- VkDisplayPlaneProperties2KHR

- VkDisplayModeProperties2KHR

- VkDisplayPlaneInfo2KHR

- VkDisplayPlaneCapabilities2KHR

#### New Functions

- vkGetPhysicalDeviceDisplayProperties2KHR

- vkGetPhysicalDeviceDisplayPlaneProperties2KHR

- vkGetDisplayModeProperties2KHR

- vkGetDisplayPlaneCapabilities2KHR

#### Issues

1) What should this extension be named?

RESOLVED: `VK_KHR_get_display_properties2`. Other alternatives:

- `VK_KHR_display2`

- One extension, combined with `VK_KHR_surface_capabilites2`.

2) Should extensible input structs be added for these new functions:

RESOLVED:

- vkGetPhysicalDeviceDisplayProperties2KHR: No. The only current input is a VkPhysicalDevice. Other inputs wouldn’t make sense.

- vkGetPhysicalDeviceDisplayPlaneProperties2KHR: No. The only current input is a VkPhysicalDevice. Other inputs wouldn’t make sense.

- vkGetDisplayModeProperties2KHR: No. The only current inputs are a VkPhysicalDevice and a VkDisplayModeKHR. Other inputs wouldn’t make sense.

3) Should additional display query functions be extended?

RESOLVED:

- vkGetDisplayPlaneSupportedDisplaysKHR: No. Extensions should instead extend vkGetDisplayPlaneCapabilitiesKHR().

#### Version History

- Revision 1, 2017-02-21 (James Jones)

  - Initial draft.

#### VK_KHR_get_surface_capabilities2

Name String

  `VK_KHR_get_surface_capabilities2`

Extension Type

  Instance extension

Registered Extension Number

  120

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_surface`

Contact

  - James Jones cubanismo

Last Modified Date

  2017-02-27

IP Status

  No known IP claims.

Contributors

  - Ian Elliott, Google

  - James Jones, NVIDIA

  - Alon Or-bach, Samsung

This extension provides new entry points to query device surface capabilities in a way that can be easily extended by other extensions, without introducing any further entry points. This extension can be considered the `VK_KHR_surface` equivalent of the `VK_KHR_get_physical_device_properties2` extension.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SURFACE_INFO_2_KHR`

  - `VK_STRUCTURE_TYPE_SURFACE_CAPABILITIES_2_KHR`

  - `VK_STRUCTURE_TYPE_SURFACE_FORMAT_2_KHR`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceSurfaceInfo2KHR

- VkSurfaceCapabilities2KHR

- VkSurfaceFormat2KHR

#### New Functions

- vkGetPhysicalDeviceSurfaceCapabilities2KHR

- vkGetPhysicalDeviceSurfaceFormats2KHR

#### Issues

1) What should this extension be named?

RESOLVED: `VK_KHR_get_surface_capabilities2`. Other alternatives:

- `VK_KHR_surface2`

- One extension, combining a separate display-specific query extension.

2) Should additional WSI query functions be extended?

RESOLVED:

- vkGetPhysicalDeviceSurfaceCapabilitiesKHR: Yes. The need for this motivated the extension.

- vkGetPhysicalDeviceSurfaceSupportKHR: No. Currently only has boolean output. Extensions should instead extend vkGetPhysicalDeviceSurfaceCapabilities2KHR.

- vkGetPhysicalDeviceSurfaceFormatsKHR: Yes.

- vkGetPhysicalDeviceSurfacePresentModesKHR: No. Recent discussion concluded this introduced too much variability for applications to deal with. Extensions should instead extend vkGetPhysicalDeviceSurfaceCapabilities2KHR.

- vkGetPhysicalDeviceXlibPresentationSupportKHR: Not in this extension.

- vkGetPhysicalDeviceXcbPresentationSupportKHR: Not in this extension.

- vkGetPhysicalDeviceWaylandPresentationSupportKHR: Not in this extension.

- vkGetPhysicalDeviceWin32PresentationSupportKHR: Not in this extension.

#### Version History

- Revision 1, 2017-02-27 (James Jones)

  - Initial draft.

#### VK_KHR_incremental_present

Name String

  `VK_KHR_incremental_present`

Extension Type

  Device extension

Registered Extension Number

  85

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_swapchain`

Contact

  - Ian Elliott ianelliottus

Last Modified Date

  2016-11-02

IP Status

  No known IP claims.

Contributors

  - Ian Elliott, Google

  - Jesse Hall, Google

  - Alon Or-bach, Samsung

  - James Jones, NVIDIA

  - Daniel Rakos, AMD

  - Ray Smith, ARM

  - Mika Isojarvi, Google

  - Jeff Juliano, NVIDIA

  - Jeff Bolz, NVIDIA

This device extension extends vkQueuePresentKHR, from the `VK_KHR_swapchain` extension, allowing an application to specify a list of rectangular, modified regions of each image to present. This should be used in situations where an application is only changing a small portion of the presentable images within a swapchain, since it enables the presentation engine to avoid wasting time presenting parts of the surface that have not changed.

This extension is leveraged from the `EGL_KHR_swap_buffers_with_damage` extension.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PRESENT_REGIONS_KHR`

#### New Enums

None.

#### New Structures

- VkRectLayerKHR

- VkPresentRegionKHR

- VkPresentRegionsKHR

#### New Functions

None.

#### Examples

None.

#### Issues

1) How should we handle steroescopic-3D swapchains? We need to add a layer for each rectangle. One approach is to create another struct containing the VkRect2D plus layer, and have VkPresentRegionsKHR point to an array of that struct. Another approach is to have two parallel arrays, `pRectangles` and `pLayers`, where `pRectangles`[i] and `pLayers`[i] must be used together. Which approach should we use, and if the array of a new structure, what should that be called?

RESOLVED: Create a new structure, which is a VkRect2D plus a layer, and will be called VkRectLayerKHR.

2) Where is the origin of the VkRectLayerKHR?

RESOLVED: The upper left corner of the presentable image(s) of the swapchain, per the definition of framebuffer coordinates.

3) Does the rectangular region, VkRectLayerKHR, specify pixels of the swapchain’s image(s), or of the surface?

RESOLVED: Of the image(s). Some presentation engines may scale the pixels of a swapchain’s image(s) to the size of the surface. The size of the swapchain’s image(s) will be consistent, where the size of the surface may vary over time.

4) What if all of the rectangles for a given swapchain contain a width and/or height of zero?

RESOLVED: The application is indicating that no pixels changed since the last present. The presentation engine may use such a hint and not update any pixels for the swapchain. However, all other semantics of vkQueuePresentKHR must still be honored, including waiting for semaphores to signal.

#### Version History

- Revision 1, 2016-11-02 (Ian Elliott)

  - Internal revisions

#### VK_KHR_performance_query

Name String

  `VK_KHR_performance_query`

Extension Type

  Device extension

Registered Extension Number

  117

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Alon Or-bach alonorbach

Last Modified Date

  2019-10-08

IP Status

  No known IP claims.

Contributors

  - Jesse Barker, Unity Technologies

  - Kenneth Benzie, Codeplay

  - Jan-Harald Fredriksen, ARM

  - Jeff Leger, Qualcomm

  - Jesse Hall, Google

  - Tobias Hector, AMD

  - Neil Henning, Codeplay

  - Baldur Karlsson

  - Lionel Landwerlin, Intel

  - Peter Lohrmann, AMD

  - Alon Or-bach, Samsung

  - Daniel Rakos, AMD

  - Niklas Smedberg, Unity Technologies

  - Igor Ostrowski, Intel

The `VK_KHR_performance_query` extension adds a mechanism to allow querying of performance counters for use in applications and by profiling tools.

Each queue family may expose counters that can be enabled on a queue of that family. We extend VkQueryType to add a new query type for performance queries, and chain a structure on VkQueryPoolCreateInfo to specify the performance queries to enable.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PERFORMANCE_QUERY_FEATURES_KHR`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PERFORMANCE_QUERY_PROPERTIES_KHR`

  - `VK_STRUCTURE_TYPE_PERFORMANCE_COUNTER_KHR`

  - `VK_STRUCTURE_TYPE_PERFORMANCE_COUNTER_DESCRIPTION_KHR`

  - `VK_STRUCTURE_TYPE_QUERY_POOL_PERFORMANCE_CREATE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_PERFORMANCE_QUERY_SUBMIT_INFO_KHR`

  - `VK_STRUCTURE_TYPE_ACQUIRE_PROFILING_LOCK_INFO_KHR`

- Extending VkQueryType:

  - `VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR`

#### New Enums

- VkPerformanceCounterScopeKHR

- VkPerformanceCounterStorageKHR

- VkPerformanceCounterUnitKHR

- VkPerformanceCounterDescriptionFlagBitsKHR

- VkAcquireProfilingLockFlagBitsKHR

#### New Structures

- VkPhysicalDevicePerformanceQueryFeaturesKHR

- VkPhysicalDevicePerformanceQueryPropertiesKHR

- VkPerformanceCounterKHR

- VkPerformanceCounterDescriptionKHR

- VkPerformanceCounterDescriptionFlagsKHR

- VkQueryPoolPerformanceCreateInfoKHR

- VkPerformanceCounterResultKHR

- VkAcquireProfilingLockInfoKHR

- VkAcquireProfilingLockFlagsKHR

- VkPerformanceQuerySubmitInfoKHR

#### New Functions

- vkEnumeratePhysicalDeviceQueueFamilyPerformanceQueryCountersKHR

- vkGetPhysicalDeviceQueueFamilyPerformanceQueryPassesKHR

- vkAcquireProfilingLockKHR

- vkReleaseProfilingLockKHR

#### Issues

1) Should this extension include a mechanism to begin a query in command buffer A and end the query in command buffer B?

RESOLVED No - queries are tied to command buffer creation and thus have to be encapsulated within a single command buffer.

2) Should this extension include a mechanism to begin and end queries globally on the queue, not using the existing command buffer commands?

RESOLVED No - for the same reasoning as the resolution of 1).

3) Should this extension expose counters that require multiple passes?

RESOLVED Yes - users should re-submit a command buffer with the same commands in it multiple times, specifying the pass to count as the query parameter in VkPerformanceQuerySubmitInfoKHR.

4) How to handle counters across parallel workloads?

RESOLVED In the spirit of Vulkan, a counter description flag `VK_PERFORMANCE_COUNTER_DESCRIPTION_CONCURRENTLY_IMPACTED_KHR` denotes that the accuracy of a counter result is affected by parallel workloads.

5) How to handle secondary command buffers?

RESOLVED Secondary command buffers inherit any counter pass index specified in the parent primary command buffer. Note: this is no longer an issue after change from issue 10 resolution

6) What commands does the profiling lock have to be held for?

RESOLVED For any command buffer that is being queried with a performance query pool, the profiling lock must be held while that command buffer is in the recording, executable, or pending state.

7) Should we support vkCmdCopyQueryPoolResults?

RESOLVED Yes.

8) Should we allow performance queries to interact with multiview?

RESOLVED Yes, but the performance queries must be performed once for each pass per view.

9) Should a `queryCount > 1` be usable for performance queries?

RESOLVED Yes. Some vendors will have costly performance counter query pool creation, and would rather if a certain set of counters were to be used multiple times that a `queryCount > 1` can be used to amortize the instantiation cost.

10) Should we introduce an indirect mechanism to set the counter pass index?

RESOLVED Specify the counter pass index at submit time instead to avoid requiring re-recording of command buffers when multiple counter passes needed.

#### Examples

The following example shows how to find what performance counters a queue family supports, setup a query pool to record these performance counters, how to add the query pool to the command buffer to record information, and how to get the results from the query pool.

    // A previously created physical device
    VkPhysicalDevice physicalDevice;

    // One of the queue families our device supports
    uint32_t queueFamilyIndex;

    uint32_t counterCount;

    // Get the count of counters supported
    vkEnumeratePhysicalDeviceQueueFamilyPerformanceQueryCountersKHR(
      physicalDevice,
      queueFamilyIndex,
      &counterCount,
      NULL,
      NULL);

    VkPerformanceCounterKHR* counters =
      malloc(sizeof(VkPerformanceCounterKHR) * counterCount);
    VkPerformanceCounterDescriptionKHR* counterDescriptions =
      malloc(sizeof(VkPerformanceCounterDescriptionKHR) * counterCount);

    // Get the counters supported
    vkEnumeratePhysicalDeviceQueueFamilyPerformanceQueryCountersKHR(
      physicalDevice,
      queueFamilyIndex,
      &counterCount,
      counters,
      counterDescriptions);

    // Try to enable the first 8 counters
    uint32_t enabledCounters[8];

    const uint32_t enabledCounterCount = min(counterCount, 8));

    for (uint32_t i = 0; i < enabledCounterCount; i++) {
      enabledCounters[i] = i;
    }

    // A previously created device that had the performanceCounterQueryPools feature
    // set to VK_TRUE
    VkDevice device;

    VkQueryPoolPerformanceCreateInfoKHR performanceQueryCreateInfo = {
      VK_STRUCTURE_TYPE_QUERY_POOL_PERFORMANCE_CREATE_INFO_KHR,
      NULL,

      // Specify the queue family that this performance query is performed on
      queueFamilyIndex,

      // The number of counters to enable
      enabledCounterCount,

      // The array of indices of counters to enable
      enabledCounters
    };

    // Get the number of passes our counters will require.
    uint32_t numPasses;

    vkGetPhysicalDeviceQueueFamilyPerformanceQueryPassesKHR(
      physicalDevice,
      &performanceQueryCreateInfo,
      &numPasses);

    VkQueryPoolCreateInfo queryPoolCreateInfo = {
      VK_STRUCTURE_TYPE_QUERY_POOL_CREATE_INFO,
      &performanceQueryCreateInfo,
      0,

      // Using our new query type here
      VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR,

      1,

      0
    };

    VkQueryPool queryPool;

    VkResult result = vkCreateQueryPool(
      device,
      &queryPoolCreateInfo,
      NULL,
      &queryPool);

    assert(VK_SUCCESS == result);

    // A queue from queueFamilyIndex
    VkQueue queue;

    // A command buffer we want to record counters on
    VkCommandBuffer commandBuffer;

    VkCommandBufferBeginInfo commandBufferBeginInfo = {
      VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO,
      NULL,
      0,
      NULL
    };

    VkAcquireProfilingLockInfoKHR lockInfo = {
      VK_STRUCTURE_TYPE_ACQUIRE_PROFILING_LOCK_INFO_KHR,
      NULL,
      0,
      UINT64_MAX // Wait forever for the lock
    };

    // Acquire the profiling lock before we record command buffers
    // that will use performance queries

    result = vkAcquireProfilingLockKHR(device, &lockInfo);

    assert(VK_SUCCESS == result);

    result = vkBeginCommandBuffer(commandBuffer, &commandBufferBeginInfo);

    assert(VK_SUCCESS == result);

    vkCmdResetQueryPool(
      commandBuffer,
      queryPool,
      0,
      1);

    vkCmdBeginQuery(
      commandBuffer,
      queryPool,
      0,
      0);

    // Perform the commands you want to get performance information on
    // ...

    // Perform a barrier to ensure all previous commands were complete before
    // ending the query
    vkCmdPipelineBarrier(commandBuffer,
      VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT,
      VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT,
      0,
      0,
      NULL,
      0,
      NULL,
      0,
      NULL);

    vkCmdEndQuery(
      commandBuffer,
      queryPool,
      0);

    result = vkEndCommandBuffer(commandBuffer);

    assert(VK_SUCCESS == result);

    for (uint32_t counterPass = 0; counterPass < numPasses; counterPass++) {

      VkPerformanceQuerySubmitInfoKHR performanceQuerySubmitInfo = {
        VK_STRUCTURE_TYPE_PERFORMANCE_QUERY_SUBMIT_INFO_KHR,
        NULL,
        counterPass
      };

      // Submit the command buffer and wait for its completion
      // ...
    }

    // Release the profiling lock after the command buffer is no longer in the
    // pending state.
    vkReleaseProfilingLockKHR(device);

    result = vkResetCommandBuffer(commandBuffer, 0);

    assert(VK_SUCCESS == result);

    // Create an array to hold the results of all counters
    VkPerformanceCounterResultKHR* recordedCounters = malloc(
      sizeof(VkPerformanceCounterResultKHR) * enabledCounterCount);

    result = vkGetQueryPoolResults(
      device,
      queryPool,
      0,
      1,
      sizeof(VkPerformanceCounterResultKHR) * enabledCounterCount,
      recordedCounters,
      sizeof(VkPerformanceCounterResultKHR),
      NULL);

    // recordedCounters is filled with our counters, we'll look at one for posterity
    switch (counters[0].storage) {
      case VK_PERFORMANCE_COUNTER_STORAGE_INT32:
        // use recordCounters[0].int32 to get at the counter result!
        break;
      case VK_PERFORMANCE_COUNTER_STORAGE_INT64:
        // use recordCounters[0].int64 to get at the counter result!
        break;
      case VK_PERFORMANCE_COUNTER_STORAGE_UINT32:
        // use recordCounters[0].uint32 to get at the counter result!
        break;
      case VK_PERFORMANCE_COUNTER_STORAGE_UINT64:
        // use recordCounters[0].uint64 to get at the counter result!
        break;
      case VK_PERFORMANCE_COUNTER_STORAGE_FLOAT32:
        // use recordCounters[0].float32 to get at the counter result!
        break;
      case VK_PERFORMANCE_COUNTER_STORAGE_FLOAT64:
        // use recordCounters[0].float64 to get at the counter result!
        break;
    }

#### Version History

- Revision 1, 2019-10-08

#### VK_KHR_pipeline_executable_properties

Name String

  `VK_KHR_pipeline_executable_properties`

Extension Type

  Device extension

Registered Extension Number

  270

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Jason Ekstrand jekstrand

Last Modified Date

  2019-05-28

IP Status

  No known IP claims.

Interactions and External Dependencies
Contributors

  - Jason Ekstrand, Intel

  - Ian Romanick, Intel

  - Kenneth Graunke, Intel

  - Baldur Karlsson, Valve

  - Jesse Hall, Google

  - Jeff Bolz, Nvidia

  - Piers Daniel, Nvidia

  - Tobias Hector, AMD

  - Jan-Harald Fredriksen, ARM

  - Tom Olson, ARM

  - Daniel Koch, Nvidia

  - Spencer Fricke, Samsung

When a pipeline is created, its state and shaders are compiled into zero or more device-specific executables, which are used when executing commands against that pipeline. This extension adds a mechanism to query properties and statistics about the different executables produced by the pipeline compilation process. This is intended to be used by debugging and performance tools to allow them to provide more detailed information to the user. Certain compile-time shader statistics provided through this extension may be useful to developers for debugging or performance analysis.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PIPELINE_EXECUTABLE_PROPERTIES_FEATURES_KHR`

  - `VK_STRUCTURE_TYPE_PIPELINE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_PIPELINE_EXECUTABLE_PROPERTIES_KHR`

  - `VK_STRUCTURE_TYPE_PIPELINE_EXECUTABLE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_PIPELINE_EXECUTABLE_STATISTIC_KHR`

  - `VK_STRUCTURE_TYPE_PIPELINE_EXECUTABLE_INTERNAL_REPRESENTATION_KHR`

- Extending VkPipelineCreateFlagBits:

  - `VK_PIPELINE_CREATE_CAPTURE_STATISTICS_BIT_KHR`

  - `VK_PIPELINE_CREATE_CAPTURE_INTERNAL_REPRESENTATIONS_BIT_KHR`

#### New Enums

- VkPipelineExecutableStatisticFormatKHR

#### New Structures

- VkPhysicalDevicePipelineExecutablePropertiesFeaturesKHR

- VkPipelineInfoKHR

- VkPipelineExecutablePropertiesKHR

- VkPipelineExecutableInfoKHR

- VkPipelineExecutableStatisticValueKHR

- VkPipelineExecutableStatisticKHR

- VkPipelineExecutableInternalRepresentationKHR

#### New Functions

- vkGetPipelineExecutablePropertiesKHR

- vkGetPipelineExecutableStatisticsKHR

- vkGetPipelineExecutableInternalRepresentationsKHR

#### Issues

1) What should we call the pieces of the pipeline which are produced by the compilation process and about which you can query properties and statistics?

RESOLVED: Call them "executables". The name "binary" was used in early drafts of the extension but it was determined that "pipeline binary" could have a fairly broad meaning (such as a binary serialized form of an entire pipeline) and was too big of a namespace for the very specific needs of this extension.

#### Version History

- Revision 1, 2019-05-28 (Jason Ekstrand)

  - Initial draft

#### VK_KHR_push_descriptor

Name String

  `VK_KHR_push_descriptor`

Extension Type

  Device extension

Registered Extension Number

  81

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Jeff Bolz jeffbolznv

Last Modified Date

  2017-09-12

IP Status

  No known IP claims.

Contributors

  - Jeff Bolz, NVIDIA

  - Michael Worcester, Imagination Technologies

This extension allows descriptors to be written into the command buffer, while the implementation is responsible for managing their memory. Push descriptors may enable easier porting from older APIs and in some cases can be more efficient than writing descriptors into descriptor sets.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PUSH_DESCRIPTOR_PROPERTIES_KHR`

- Extending VkDescriptorSetLayoutCreateFlagBits

  - `VK_DESCRIPTOR_SET_LAYOUT_CREATE_PUSH_DESCRIPTOR_BIT_KHR`

- Extending VkDescriptorUpdateTemplateType

  - `VK_DESCRIPTOR_UPDATE_TEMPLATE_TYPE_PUSH_DESCRIPTORS_KHR`

#### New Enums

None.

#### New Structures

- VkPhysicalDevicePushDescriptorPropertiesKHR

#### New Functions

- vkCmdPushDescriptorSetKHR

- vkCmdPushDescriptorSetWithTemplateKHR

#### Issues

None.

#### Examples

None.

#### Version History

- Revision 1, 2016-10-15 (Jeff Bolz)

  - Internal revisions

- Revision 2, 2017-09-12 (Tobias Hector)

  - Added interactions with Vulkan 1.1

#### VK_KHR_shader_clock

Name String

  `VK_KHR_shader_clock`

Extension Type

  Device extension

Registered Extension Number

  182

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Aaron Hagan ahagan

Last Modified Date

  2019-4-25

IP Status

  No known IP claims.

Interactions and External Dependencies

  - This extension requires `SPV_KHR_shader_clock`.

  - This extension enables `ARB_shader_clock` for GLSL source languages.

  - This extension enables `EXT_shader_realtime_clock` for GLSL source languages.

Contributors

  - Aaron Hagan, AMD

  - Daniel Koch, NVIDIA

This extension advertises the SPIR-V `ShaderClockKHR` capability for Vulkan, which allows a shader to query a real-time or monotonically incrementing counter at the subgroup level or across the device level. The two valid SPIR-V scopes for `OpReadClockKHR` are `Subgroup` and `Device`.

When using GLSL source-based shading languages, the `clockRealtime`*`EXT`() timing functions map to the `OpReadClockKHR` instruction with a scope of `Device`, and the `clock`*`ARB`() timing functions map to the `OpReadClockKHR` instruction with a scope of `Subgroup`.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_CLOCK_FEATURES_KHR`

#### New SPIR-V Capabilities

- `ShaderClockKHR`

#### New Structures

- VkPhysicalDeviceShaderClockFeaturesKHR

#### Version History

- Revision 1, 2019-4-25 (Aaron Hagan)

  - Initial revision

#### VK_KHR_shader_non_semantic_info

Name String

  `VK_KHR_shader_non_semantic_info`

Extension Type

  Device extension

Registered Extension Number

  294

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Baldur Karlsson baldurk

Last Modified Date

  2019-10-16

IP Status

  No known IP claims.

Interactions and External Dependencies

  - This extension requires the `SPV_KHR_non_semantic_info` SPIR-V extension.

Contributors

  - Baldur Karlsson, Valve

This extension allows the use of the `SPV_KHR_non_semantic_info` extension in SPIR-V shader modules.

#### New Object Types

None.

#### New Enum Constants

None.

#### New SPIR-V Capabilities

None.

#### New Structures

None.

#### Version History

- Revision 1, 2019-10-16 (Baldur Karlsson)

  - Initial revision

#### VK_KHR_shared_presentable_image

Name String

  `VK_KHR_shared_presentable_image`

Extension Type

  Device extension

Registered Extension Number

  112

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_swapchain`

  - Requires `VK_KHR_get_physical_device_properties2`

  - Requires `VK_KHR_get_surface_capabilities2`

Contact

  - Alon Or-bach alonorbach

Last Modified Date

  2017-03-20

IP Status

  No known IP claims.

Contributors

  - Alon Or-bach, Samsung Electronics

  - Ian Elliott, Google

  - Jesse Hall, Google

  - Pablo Ceballos, Google

  - Chris Forbes, Google

  - Jeff Juliano, NVIDIA

  - James Jones, NVIDIA

  - Daniel Rakos, AMD

  - Tobias Hector, Imagination Technologies

  - Graham Connor, Imagination Technologies

  - Michael Worcester, Imagination Technologies

  - Cass Everitt, Oculus

  - Johannes Van Waveren, Oculus

This extension extends `VK_KHR_swapchain` to enable creation of a shared presentable image. This allows the application to use the image while the presention engine is accessing it, in order to reduce the latency between rendering and presentation.

#### New Object Types

None.

#### New Enum Constants

- Extending VkPresentModeKHR:

  - `VK_PRESENT_MODE_SHARED_DEMAND_REFRESH_KHR`

  - `VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR`

- Extending VkImageLayout:

  - `VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR`

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_SHARED_PRESENT_SURFACE_CAPABILITIES_KHR`

#### New Enums

None.

#### New Structures

- VkSharedPresentSurfaceCapabilitiesKHR

#### New Functions

- vkGetSwapchainStatusKHR

#### Issues

1) Should we allow a Vulkan WSI swapchain to toggle between normal usage and shared presentation usage?

RESOLVED: No. WSI swapchains are typically recreated with new properties instead of having their properties changed. This can also save resources, assuming that fewer images are needed for shared presentation, and assuming that most VR applications do not need to switch between normal and shared usage.

2) Should we have a query for determining how the presentation engine refresh is triggered?

RESOLVED: Yes. This is done via which presentation modes a surface supports.

3) Should the object representing a shared presentable image be an extension of a VkSwapchainKHR or a separate object?

RESOLVED: Extension of a swapchain due to overlap in creation properties and to allow common functionality between shared and normal presentable images and swapchains.

4) What should we call the extension and the new structures it creates?

RESOLVED: Shared presentable image / shared present.

5) Should the `minImageCount` and `presentMode` values of the VkSwapchainCreateInfoKHR be ignored, or required to be compatible values?

RESOLVED: `minImageCount` must be set to 1, and `presentMode` should be set to either `VK_PRESENT_MODE_SHARED_DEMAND_REFRESH_KHR` or `VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR`.

6) What should the layout of the shared presentable image be?

RESOLVED: After acquiring the shared presentable image, the application must transition it to the `VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR` layout prior to it being used. After this initial transition, any image usage that was requested during swapchain creation can be performed on the image without layout transitions being performed.

7) Do we need a new API for the trigger to refresh new content?

RESOLVED: vkQueuePresentKHR to act as API to trigger a refresh, as will allow combination with other compatible extensions to vkQueuePresentKHR.

8) How should an application detect a `VK_ERROR_OUT_OF_DATE_KHR` error on a swapchain using the `VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR` present mode?

RESOLVED: Introduce vkGetSwapchainStatusKHR to allow applications to query the status of a swapchain using a shared presentation mode.

9) What should subsequent calls to vkQueuePresentKHR for `VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR` swapchains be defined to do?

RESOLVED: State that implementations may use it as a hint for updated content.

10) Can the ownership of a shared presentable image be transferred to a different queue?

RESOLVED: No. It is not possible to transfer ownership of a shared presentable image obtained from a swapchain created using `VK_SHARING_MODE_EXCLUSIVE` after it has been presented.

11) How should vkQueueSubmit behave if a command buffer uses an image from a `VK_ERROR_OUT_OF_DATE_KHR` swapchain?

RESOLVED: vkQueueSubmit is expected to return the `VK_ERROR_DEVICE_LOST` error.

12) Can Vulkan provide any guarantee on the order of rendering, to enable beam chasing?

RESOLVED: This could be achieved via use of render passes to ensure strip rendering.

#### Version History

- Revision 1, 2017-03-20 (Alon Or-bach)

  - Internal revisions

#### VK_KHR_surface

Name String

  `VK_KHR_surface`

Extension Type

  Instance extension

Registered Extension Number

  1

Revision

  25

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - James Jones cubanismo

  - Ian Elliott ianelliottus

Last Modified Date

  2016-08-25

IP Status

  No known IP claims.

Contributors

  - Patrick Doane, Blizzard

  - Ian Elliott, LunarG

  - Jesse Hall, Google

  - James Jones, NVIDIA

  - David Mao, AMD

  - Norbert Nopper, Freescale

  - Alon Or-bach, Samsung

  - Daniel Rakos, AMD

  - Graham Sellers, AMD

  - Jeff Vigil, Qualcomm

  - Chia-I Wu, LunarG

  - Jason Ekstrand, Intel

The `VK_KHR_surface` extension is an instance extension. It introduces VkSurfaceKHR objects, which abstract native platform surface or window objects for use with Vulkan. It also provides a way to determine whether a queue family in a physical device supports presenting to particular surface.

Separate extensions for each platform provide the mechanisms for creating VkSurfaceKHR objects, but once created they may be used in this and other platform-independent extensions, in particular the `VK_KHR_swapchain` extension.

#### New Object Types

- VkSurfaceKHR

#### New Enum Constants

- Extending VkResult:

  - `VK_ERROR_SURFACE_LOST_KHR`

  - `VK_ERROR_NATIVE_WINDOW_IN_USE_KHR`

#### New Enums

- VkSurfaceTransformFlagBitsKHR

- VkPresentModeKHR

- VkColorSpaceKHR

- VkCompositeAlphaFlagBitsKHR

#### New Structures

- VkSurfaceCapabilitiesKHR

- VkSurfaceFormatKHR

#### New Functions

- vkDestroySurfaceKHR

- vkGetPhysicalDeviceSurfaceSupportKHR

- vkGetPhysicalDeviceSurfaceCapabilitiesKHR

- vkGetPhysicalDeviceSurfaceFormatsKHR

- vkGetPhysicalDeviceSurfacePresentModesKHR

#### Examples

| Note The example code for the `VK_KHR_surface` and `VK_KHR_swapchain` extensions was removed from the appendix after revision 1.0.29. This WSI example code was ported to the cube demo that is shipped with the official Khronos SDK, and is being kept up-to-date in that location (see: https://github.com/KhronosGroup/Vulkan-Tools/blob/master/cube/cube.c).

#### Issues

1) Should this extension include a method to query whether a physical device supports presenting to a specific window or native surface on a given platform?

RESOLVED: Yes. Without this, applications would need to create a device instance to determine whether a particular window can be presented to. Knowing that a device supports presentation to a platform in general is not sufficient, as a single machine might support multiple seats, or instances of the platform that each use different underlying physical devices. Additionally, on some platforms, such as the X Window System, different drivers and devices might be used for different windows depending on which section of the desktop they exist on.

2) Should the vkGetPhysicalDeviceSurfaceCapabilitiesKHR, vkGetPhysicalDeviceSurfaceFormatsKHR, and vkGetPhysicalDeviceSurfacePresentModesKHR functions be in this extension and operate on physical devices, rather than being in `VK_KHR_swapchain` (i.e. device extension) and being dependent on VkDevice?

RESOLVED: Yes. While it might be useful to depend on `VkDevice` (and therefore on enabled extensions and features) for the queries, Vulkan was released only with the VkPhysicalDevice versions. Many cases can be resolved by a Valid Usage. And\or by a separate `pNext` chain version of the query struct specific to a given extension or parameters, via extensible versions of the queries: `vkGetPhysicalDeviceSurfaceCapabilities2KHR`, `vkGetPhysicalDeviceSurfaceFormats2KHR`, and `vkGetPhysicalDeviceSurfacePresentModes2EXT`.

3) Should Vulkan include support Xlib or XCB as the API for accessing the X Window System platform?

RESOLVED: Both. XCB is a more modern and efficient API, but Xlib usage is deeply ingrained in many applications and likely will remain in use for the foreseeable future. Not all drivers necessarily need to support both, but including both as options in the core specification will probably encourage support, which should in turn ease adoption of the Vulkan API in older codebases. Additionally, the performance improvements possible with XCB likely will not have a measurable impact on the performance of Vulkan presentation and other minimal window system interactions defined here.

4) Should the GBM platform be included in the list of platform enums?

RESOLVED: Deferred, and will be addressed with a platform-specific extension to be written in the future.

#### Version History

- Revision 1, 2015-05-20 (James Jones)

  - Initial draft, based on LunarG KHR spec, other KHR specs, patches attached to bugs.

- Revision 2, 2015-05-22 (Ian Elliott)

  - Created initial Description section.

  - Removed query for whether a platform requires the use of a queue for presentation, since it was decided that presentation will always be modeled as being part of the queue.

  - Fixed typos and other minor mistakes.

- Revision 3, 2015-05-26 (Ian Elliott)

  - Improved the Description section.

- Revision 4, 2015-05-27 (James Jones)

  - Fixed compilation errors in example code.

- Revision 5, 2015-06-01 (James Jones)

  - Added issues 1 and 2 and made related spec updates.

- Revision 6, 2015-06-01 (James Jones)

  - Merged the platform type mappings table previously removed from VK_KHR_swapchain with the platform description table in this spec.

  - Added issues 3 and 4 documenting choices made when building the initial list of native platforms supported.

- Revision 7, 2015-06-11 (Ian Elliott)

  - Updated table 1 per input from the KHR TSG.

  - Updated issue 4 (GBM) per discussion with Daniel Stone. He will create a platform-specific extension sometime in the future.

- Revision 8, 2015-06-17 (James Jones)

  - Updated enum-extending values using new convention.

  - Fixed the value of VK_SURFACE_PLATFORM_INFO_TYPE_SUPPORTED_KHR.

- Revision 9, 2015-06-17 (James Jones)

  - Rebased on Vulkan API version 126.

- Revision 10, 2015-06-18 (James Jones)

  - Marked issues 2 and 3 resolved.

- Revision 11, 2015-06-23 (Ian Elliott)

  - Examples now show use of function pointers for extension functions.

  - Eliminated extraneous whitespace.

- Revision 12, 2015-07-07 (Daniel Rakos)

  - Added error section describing when each error is expected to be reported.

  - Replaced the term "queue node index" with "queue family index" in the spec as that is the agreed term to be used in the latest version of the core header and spec.

  - Replaced bool32_t with VkBool32.

- Revision 13, 2015-08-06 (Daniel Rakos)

  - Updated spec against latest core API header version.

- Revision 14, 2015-08-20 (Ian Elliott)

  - Renamed this extension and all of its enumerations, types, functions, etc. This makes it compliant with the proposed standard for Vulkan extensions.

  - Switched from "revision" to "version", including use of the VK_MAKE_VERSION macro in the header file.

  - Did miscellaneous cleanup, etc.

- Revision 15, 2015-08-20 (Ian Elliott—​porting a 2015-07-29 change from James Jones)

  - Moved the surface transform enums here from VK_WSI_swapchain so they could be re-used by VK_WSI_display.

- Revision 16, 2015-09-01 (James Jones)

  - Restore single-field revision number.

- Revision 17, 2015-09-01 (James Jones)

  - Fix example code compilation errors.

- Revision 18, 2015-09-26 (Jesse Hall)

  - Replaced VkSurfaceDescriptionKHR with the VkSurfaceKHR object, which is created via layered extensions. Added VkDestroySurfaceKHR.

- Revision 19, 2015-09-28 (Jesse Hall)

  - Renamed from VK_EXT_KHR_swapchain to VK_EXT_KHR_surface.

- Revision 20, 2015-09-30 (Jeff Vigil)

  - Add error result VK_ERROR_SURFACE_LOST_KHR.

- Revision 21, 2015-10-15 (Daniel Rakos)

  - Updated the resolution of issue #2 and include the surface capability queries in this extension.

  - Renamed SurfaceProperties to SurfaceCapabilities as it better reflects that the values returned are the capabilities of the surface on a particular device.

  - Other minor cleanup and consistency changes.

- Revision 22, 2015-10-26 (Ian Elliott)

  - Renamed from VK_EXT_KHR_surface to VK_KHR_surface.

- Revision 23, 2015-11-03 (Daniel Rakos)

  - Added allocation callbacks to vkDestroySurfaceKHR.

- Revision 24, 2015-11-10 (Jesse Hall)

  - Removed VkSurfaceTransformKHR. Use VkSurfaceTransformFlagBitsKHR instead.

  - Rename VkSurfaceCapabilitiesKHR member maxImageArraySize to maxImageArrayLayers.

- Revision 25, 2016-01-14 (James Jones)

  - Moved VK_ERROR_NATIVE_WINDOW_IN_USE_KHR from the VK_KHR_android_surface to the VK_KHR_surface extension.

- 2016-08-23 (Ian Elliott)

  - Update the example code, to not have so many characters per line, and to split out a new example to show how to obtain function pointers.

- 2016-08-25 (Ian Elliott)

  - A note was added at the beginning of the example code, stating that it will be removed from future versions of the appendix.

#### VK_KHR_surface_protected_capabilities

Name String

  `VK_KHR_surface_protected_capabilities`

Extension Type

  Instance extension

Registered Extension Number

  240

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.1

  - Requires `VK_KHR_get_surface_capabilities2`

Contact

  - Sandeep Shinde sashinde

Last Modified Date

  2018-12-18

IP Status

  No known IP claims.

Contributors

  - Sandeep Shinde, NVIDIA

  - James Jones, NVIDIA

  - Daniel Koch, NVIDIA

This extension extends VkSurfaceCapabilities2KHR, providing applications a way to query whether swapchains can be created with the `VK_SWAPCHAIN_CREATE_PROTECTED_BIT_KHR` flag set.

Vulkan 1.1 added (optional) support for protect memory and protected resources including buffers (`VK_BUFFER_CREATE_PROTECTED_BIT`), images (`VK_IMAGE_CREATE_PROTECTED_BIT`), and swapchains (`VK_SWAPCHAIN_CREATE_PROTECTED_BIT_KHR`). However, on implementations which support multiple windowing systems, not all window systems may be able to provide a protected display path.

This extension provides a way to query if a protected swapchain created for a surface (and thus a specific windowing system) can be displayed on screen. It extends the existing VkSurfaceCapabilities2KHR structure with a new VkSurfaceProtectedCapabilitiesKHR structure from which the application can obtain information about support for protected swapchain creation through vkGetPhysicalDeviceSurfaceCapabilities2KHR.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_SURFACE_PROTECTED_CAPABILITIES_KHR`

#### New Enums

None.

#### New Structures

- VkSurfaceProtectedCapabilitiesKHR

#### New Functions

None.

#### Issues

None.

#### Version History

- Revision 1, 2018-12-18 (Sandeep Shinde, Daniel Koch)

  - Internal revisions.

#### VK_KHR_swapchain

Name String

  `VK_KHR_swapchain`

Extension Type

  Device extension

Registered Extension Number

  2

Revision

  70

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_surface`

Contact

  - James Jones cubanismo

  - Ian Elliott ianelliottus

Last Modified Date

  2017-10-06

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Interacts with Vulkan 1.1

Contributors

  - Patrick Doane, Blizzard

  - Ian Elliott, LunarG

  - Jesse Hall, Google

  - Mathias Heyer, NVIDIA

  - James Jones, NVIDIA

  - David Mao, AMD

  - Norbert Nopper, Freescale

  - Alon Or-bach, Samsung

  - Daniel Rakos, AMD

  - Graham Sellers, AMD

  - Jeff Vigil, Qualcomm

  - Chia-I Wu, LunarG

  - Jason Ekstrand, Intel

  - Matthaeus G. Chajdas, AMD

  - Ray Smith, ARM

The `VK_KHR_swapchain` extension is the device-level companion to the `VK_KHR_surface` extension. It introduces VkSwapchainKHR objects, which provide the ability to present rendering results to a surface.

#### New Object Types

- VkSwapchainKHR

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_SWAPCHAIN_CREATE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_PRESENT_INFO_KHR`

  - `VK_STRUCTURE_TYPE_DEVICE_GROUP_PRESENT_CAPABILITIES_KHR`

  - `VK_STRUCTURE_TYPE_IMAGE_SWAPCHAIN_CREATE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_SWAPCHAIN_INFO_KHR`

  - `VK_STRUCTURE_TYPE_ACQUIRE_NEXT_IMAGE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_DEVICE_GROUP_PRESENT_INFO_KHR`

  - `VK_STRUCTURE_TYPE_DEVICE_GROUP_SWAPCHAIN_CREATE_INFO_KHR`

- Extending VkImageLayout:

  - `VK_IMAGE_LAYOUT_PRESENT_SRC_KHR`

- Extending VkResult:

  - `VK_SUBOPTIMAL_KHR`

  - `VK_ERROR_OUT_OF_DATE_KHR`

#### New Enums

- VkDeviceGroupPresentModeFlagBitsKHR

- VkSwapchainCreateFlagBitsKHR

#### New Structures

- VkSwapchainCreateInfoKHR

- VkPresentInfoKHR

- VkDeviceGroupPresentCapabilitiesKHR

- VkImageSwapchainCreateInfoKHR

- VkBindImageMemorySwapchainInfoKHR

- VkAcquireNextImageInfoKHR

- VkDeviceGroupPresentInfoKHR

- VkDeviceGroupSwapchainCreateInfoKHR

#### New Functions

- vkCreateSwapchainKHR

- vkDestroySwapchainKHR

- vkGetSwapchainImagesKHR

- vkAcquireNextImageKHR

- vkQueuePresentKHR

- vkGetDeviceGroupPresentCapabilitiesKHR

- vkGetDeviceGroupSurfacePresentModesKHR

- vkGetPhysicalDevicePresentRectanglesKHR

- vkAcquireNextImage2KHR

#### Issues

1) Does this extension allow the application to specify the memory backing of the presentable images?

RESOLVED: No. Unlike standard images, the implementation will allocate the memory backing of the presentable image.

2) What operations are allowed on presentable images?

RESOLVED: This is determined by the image usage flags specified when creating the presentable image’s swapchain.

3) Does this extension support MSAA presentable images?

RESOLVED: No. Presentable images are always single-sampled. Multi-sampled rendering must use regular images. To present the rendering results the application must manually resolve the multi- sampled image to a single-sampled presentable image prior to presentation.

4) Does this extension support stereo/multi-view presentable images?

RESOLVED: Yes. The number of views associated with a presentable image is determined by the `imageArrayLayers` specified when creating a swapchain. All presentable images in a given swapchain use the same array size.

5) Are the layers of stereo presentable images half-sized?

RESOLVED: No. The image extents always match those requested by the application.

6) Do the “present” and “acquire next image” commands operate on a queue? If not, do they need to include explicit semaphore objects to interlock them with queue operations?

RESOLVED: The present command operates on a queue. The image ownership operation it represents happens in order with other operations on the queue, so no explicit semaphore object is required to synchronize its actions.

Applications may want to acquire the next image in separate threads from those in which they manage their queue, or in multiple threads. To make such usage easier, the acquire next image command takes a semaphore to signal as a method of explicit synchronization. The application must later queue a wait for this semaphore before queuing execution of any commands using the image.

7) Does vkAcquireNextImageKHR block if no images are available?

RESOLVED: The command takes a timeout parameter. Special values for the timeout are 0, which makes the call a non-blocking operation, and `UINT64_MAX`, which blocks indefinitely. Values in between will block for up to the specified time. The call will return when an image becomes available or an error occurs. It may, but is not required to, return before the specified timeout expires if the swapchain becomes out of date.

8) Can multiple presents be queued using one vkQueuePresentKHR call?

RESOLVED: Yes. VkPresentInfoKHR contains a list of swapchains and corresponding image indices that will be presented. When supported, all presentations queued with a single vkQueuePresentKHR call will be applied atomically as one operation. The same swapchain must not appear in the list more than once. Later extensions may provide applications stronger guarantees of atomicity for such present operations, and/or allow them to query whether atomic presentation of a particular group of swapchains is possible.

9) How do the presentation and acquire next image functions notify the application the targeted surface has changed?

RESOLVED: Two new result codes are introduced for this purpose:

- `VK_SUBOPTIMAL_KHR` - Presentation will still succeed, subject to the window resize behavior, but the swapchain is no longer configured optimally for the surface it targets. Applications should query updated surface information and recreate their swapchain at the next convenient opportunity.

- `VK_ERROR_OUT_OF_DATE_KHR` - Failure. The swapchain is no longer compatible with the surface it targets. The application must query updated surface information and recreate the swapchain before presentation will succeed.

These can be returned by both vkAcquireNextImageKHR and vkQueuePresentKHR.

10) Does the vkAcquireNextImageKHR command return a semaphore to the application via an output parameter, or accept a semaphore to signal from the application as an object handle parameter?

RESOLVED: Accept a semaphore to signal as an object handle. This avoids the need to specify whether the application must destroy the semaphore or whether it is owned by the swapchain, and if the latter, what its lifetime is and whether it can be re-used for other operations once it is received from vkAcquireNextImageKHR.

11) What types of swapchain queuing behavior should be exposed? Options include swap interval specification, mailbox/most recent vs. FIFO queue management, targeting specific vertical blank intervals or absolute times for a given present operation, and probably others. For some of these, whether they are specified at swapchain creation time or as per-present parameters needs to be decided as well.

RESOLVED: The base swapchain extension will expose 3 possible behaviors (of which, FIFO will always be supported):

- Immediate present: Does not wait for vertical blanking period to update the current image, likely resulting in visible tearing. No internal queue is used. Present requests are applied immediately.

- Mailbox queue: Waits for the next vertical blanking period to update the current image. No tearing should be observed. An internal single-entry queue is used to hold pending presentation requests. If the queue is full when a new presentation request is received, the new request replaces the existing entry, and any images associated with the prior entry become available for re-use by the application.

- FIFO queue: Waits for the next vertical blanking period to update the current image. No tearing should be observed. An internal queue containing `numSwapchainImages` - 1 entries is used to hold pending presentation requests. New requests are appended to the end of the queue, and one request is removed from the beginning of the queue and processed during each vertical blanking period in which the queue is non-empty

Not all surfaces will support all of these modes, so the modes supported will be returned using a surface info query. All surfaces must support the FIFO queue mode. Applications must choose one of these modes up front when creating a swapchain. Switching modes can be accomplished by recreating the swapchain.

12) Can `VK_PRESENT_MODE_MAILBOX_KHR` provide non-blocking guarantees for vkAcquireNextImageKHR? If so, what is the proper criteria?

RESOLVED: Yes. The difficulty is not immediately obvious here. Naively, if at least 3 images are requested, mailbox mode should always have an image available for the application if the application does not own any images when the call to vkAcquireNextImageKHR was made. However, some presentation engines may have more than one “current” image, and would still need to block in some cases. The right requirement appears to be that if the application allocates the surface’s minimum number of images + 1 then it is guaranteed non-blocking behavior when it does not currently own any images.

13) Is there a way to create and initialize a new swapchain for a surface that has generated a `VK_SUBOPTIMAL_KHR` return code while still using the old swapchain?

RESOLVED: Not as part of this specification. This could be useful to allow the application to create an “optimal” replacement swapchain and rebuild all its command buffers using it in a background thread at a low priority while continuing to use the “suboptimal” swapchain in the main thread. It could probably use the same “atomic replace” semantics proposed for recreating direct-to-device swapchains without incurring a mode switch. However, after discussion, it was determined some platforms probably could not support concurrent swapchains for the same surface though, so this will be left out of the base KHR extensions. A future extension could add this for platforms where it is supported.

14) Should there be a special value for VkSurfaceCapabilitiesKHR::`maxImageCount` to indicate there are no practical limits on the number of images in a swapchain?

RESOLVED: Yes. There where often be cases where there is no practical limit to the number of images in a swapchain other than the amount of available resources (I.e., memory) in the system. Trying to derive a hard limit from things like memory size is prone to failure. It is better in such cases to leave it to applications to figure such soft limits out via trial/failure iterations.

15) Should there be a special value for VkSurfaceCapabilitiesKHR::`currentExtent` to indicate the size of the platform surface is undefined?

RESOLVED: Yes. On some platforms (Wayland, for example), the surface size is defined by the images presented to it rather than the other way around.

16) Should there be a special value for VkSurfaceCapabilitiesKHR::`maxImageExtent` to indicate there is no practical limit on the surface size?

RESOLVED: No. It seems unlikely such a system would exist. 0 could be used to indicate the platform places no limits on the extents beyond those imposed by Vulkan for normal images, but this query could just as easily return those same limits, so a special “unlimited” value does not seem useful for this field.

17) How should surface rotation and mirroring be exposed to applications? How do they specify rotation and mirroring transforms applied prior to presentation?

RESOLVED: Applications can query both the supported and current transforms of a surface. Both are specified relative to the device’s “natural” display rotation and direction. The supported transforms indicates which orientations the presentation engine accepts images in. For example, a presentation engine that does not support transforming surfaces as part of presentation, and which is presenting to a surface that is displayed with a 90-degree rotation, would return only one supported transform bit: `VK_SURFACE_TRANSFORM_ROTATE_90_BIT_KHR`. Applications must transform their rendering by the transform they specify when creating the swapchain in `preTransform` field.

18) Can surfaces ever not support `VK_MIRROR_NONE`? Can they support vertical and horizontal mirroring simultaneously? Relatedly, should `VK_MIRROR_NONE`[_BIT] be zero, or bit one, and should applications be allowed to specify multiple pre and current mirror transform bits, or exactly one?

RESOLVED: Since some platforms may not support presenting with a transform other than the native window’s current transform, and prerotation/mirroring are specified relative to the device’s natural rotation and direction, rather than relative to the surface’s current rotation and direction, it is necessary to express lack of support for no mirroring. To allow this, the `MIRROR_NONE` enum must occupy a bit in the flags. Since `MIRROR_NONE` must be a bit in the bitmask rather than a bitmask with no values set, allowing more than one bit to be set in the bitmask would make it possible to describe undefined transforms such as `VK_MIRROR_NONE_BIT` | `VK_MIRROR_HORIZONTAL_BIT`, or a transform that includes both “no mirroring” and “horizontal mirroring” simultaneously. Therefore, it is desirable to allow specifying all supported mirroring transforms using only one bit. The question then becomes, should there be a `VK_MIRROR_HORIZONTAL_AND_VERTICAL_BIT` to represent a simultaneous horizontal and vertical mirror transform? However, such a transform is equivalent to a 180 degree rotation, so presentation engines and applications that wish to support or use such a transform can express it through rotation instead. Therefore, 3 exclusive bits are sufficient to express all needed mirroring transforms.

19) Should support for sRGB be required?

RESOLVED: In the advent of UHD and HDR display devices, proper color space information is vital to the display pipeline represented by the swapchain. The app can discover the supported format/color-space pairs and select a pair most suited to its rendering needs. Currently only the sRGB color space is supported, future extensions may provide support for more color spaces. See issues 23 and 24.

20) Is there a mechanism to modify or replace an existing swapchain with one targeting the same surface?

RESOLVED: Yes. This is described above in the text.

21) Should there be a way to set prerotation and mirroring using native APIs when presenting using a Vulkan swapchain?

RESOLVED: Yes. The transforms that can be expressed in this extension are a subset of those possible on native platforms. If a platform exposes a method to specify the transform of presented images for a given surface using native methods and exposes more transforms or other properties for surfaces than Vulkan supports, it might be impossible, difficult, or inconvenient to set some of those properties using Vulkan KHR extensions and some using the native interfaces. To avoid overwriting properties set using native commands when presenting using a Vulkan swapchain, the application can set the pretransform to “inherit”, in which case the current native properties will be used, or if none are available, a platform-specific default will be used. Platforms that do not specify a reasonable default or do not provide native mechanisms to specify such transforms should not include the inherit bits in the `supportedTransforms` bitmask they return in VkSurfaceCapabilitiesKHR.

22) Should the content of presentable images be clipped by objects obscuring their target surface?

RESOLVED: Applications can choose which behavior they prefer. Allowing the content to be clipped could enable more optimal presentation methods on some platforms, but some applications might rely on the content of presentable images to perform techniques such as partial updates or motion blurs.

23) What is the purpose of specifying a VkColorSpaceKHR along with VkFormat when creating a swapchain?

RESOLVED: While Vulkan itself is color space agnostic (e.g. even the meaning of R, G, B and A can be freely defined by the rendering application), the swapchain eventually will have to present the images on a display device with specific color reproduction characteristics. If any color space transformations are necessary before an image can be displayed, the color space of the presented image must be known to the swapchain. A swapchain will only support a restricted set of color format and -space pairs. This set can be discovered via vkGetPhysicalDeviceSurfaceFormatsKHR. As it can be expected that most display devices support the sRGB color space, at least one format/color-space pair has to be exposed, where the color space is `VK_COLOR_SPACE_SRGB_NONLINEAR_KHR`.

24) How are sRGB formats and the sRGB color space related?

RESOLVED: While Vulkan exposes a number of SRGB texture formats, using such formats does not guarantee working in a specific color space. It merely means that the hardware can directly support applying the non-linear transfer functions defined by the sRGB standard color space when reading from or writing to images of that these formats. Still, it is unlikely that a swapchain will expose a `*_SRGB` format along with any color space other than `VK_COLOR_SPACE_SRGB_NONLINEAR_KHR`.

On the other hand, non-`*_SRGB` formats will be very likely exposed in pair with a SRGB color space. This means, the hardware will not apply any transfer function when reading from or writing to such images, yet they will still be presented on a device with sRGB display characteristics. In this case the application is responsible for applying the transfer function, for instance by using shader math.

25) How are the lifetime of surfaces and swapchains targeting them related?

RESOLVED: A surface must outlive any swapchains targeting it. A VkSurfaceKHR owns the binding of the native window to the Vulkan driver.

26) How can the client control the way the alpha channel of swapchain images is treated by the presentation engine during compositing?

RESOLVED: We should add new enum values to allow the client to negotiate with the presentation engine on how to treat image alpha values during the compositing process. Since not all platforms can practically control this through the Vulkan driver, a value of `VK_COMPOSITE_ALPHA_INHERIT_BIT_KHR` is provided like for surface transforms.

27) Is vkCreateSwapchainKHR the right function to return `VK_ERROR_NATIVE_WINDOW_IN_USE_KHR`, or should the various platform-specific VkSurfaceKHR factory functions catch this error earlier?

RESOLVED: For most platforms, the VkSurfaceKHR structure is a simple container holding the data that identifies a native window or other object representing a surface on a particular platform. For the surface factory functions to return this error, they would likely need to register a reference on the native objects with the native display server somehow, and ensure no other such references exist. Surfaces were not intended to be that heavyweight.

Swapchains are intended to be the objects that directly manipulate native windows and communicate with the native presentation mechanisms. Swapchains will already need to communicate with the native display server to negotiate allocation and/or presentation of presentable images for a native surface. Therefore, it makes more sense for swapchain creation to be the point at which native object exclusivity is enforced. Platforms may choose to enforce further restrictions on the number of VkSurfaceKHR objects that may be created for the same native window if such a requirement makes sense on a particular platform, but a global requirement is only sensible at the swapchain level.

#### Examples

| Note The example code for the `VK_KHR_surface` and `VK_KHR_swapchain` extensions was removed from the appendix after revision 1.0.29. This WSI example code was ported to the cube demo that is shipped with the official Khronos SDK, and is being kept up-to-date in that location (see: https://github.com/KhronosGroup/Vulkan-Tools/blob/master/cube/cube.c).

#### Version History

- Revision 1, 2015-05-20 (James Jones)

  - Initial draft, based on LunarG KHR spec, other KHR specs, patches attached to bugs.

- Revision 2, 2015-05-22 (Ian Elliott)

  - Made many agreed-upon changes from 2015-05-21 KHR TSG meeting. This includes using only a queue for presentation, and having an explicit function to acquire the next image.

  - Fixed typos and other minor mistakes.

- Revision 3, 2015-05-26 (Ian Elliott)

  - Improved the Description section.

  - Added or resolved issues that were found in improving the Description. For example, pSurfaceDescription is used consistently, instead of sometimes using pSurface.

- Revision 4, 2015-05-27 (James Jones)

  - Fixed some grammatical errors and typos

  - Filled in the description of imageUseFlags when creating a swapchain.

  - Added a description of swapInterval.

  - Replaced the paragraph describing the order of operations on a queue for image ownership and presentation.

- Revision 5, 2015-05-27 (James Jones)

  - Imported relevant issues from the (abandoned) vk_wsi_persistent_swapchain_images extension.

  - Added issues 6 and 7, regarding behavior of the acquire next image and present commands with respect to queues.

  - Updated spec language and examples to align with proposed resolutions to issues 6 and 7.

- Revision 6, 2015-05-27 (James Jones)

  - Added issue 8, regarding atomic presentation of multiple swapchains

  - Updated spec language and examples to align with proposed resolution to issue 8.

- Revision 7, 2015-05-27 (James Jones)

  - Fixed compilation errors in example code, and made related spec fixes.

- Revision 8, 2015-05-27 (James Jones)

  - Added issue 9, and the related VK_SUBOPTIMAL_KHR result code.

  - Renamed VK_OUT_OF_DATE_KHR to VK_ERROR_OUT_OF_DATE_KHR.

- Revision 9, 2015-05-27 (James Jones)

  - Added inline proposed resolutions (marked with [JRJ]) to some XXX questions/issues. These should be moved to the issues section in a subsequent update if the proposals are adopted.

- Revision 10, 2015-05-28 (James Jones)

  - Converted vkAcquireNextImageKHR back to a non-queue operation that uses a VkSemaphore object for explicit synchronization.

  - Added issue 10 to determine whether vkAcquireNextImageKHR generates or returns semaphores, or whether it operates on a semaphore provided by the application.

- Revision 11, 2015-05-28 (James Jones)

  - Marked issues 6, 7, and 8 resolved.

  - Renamed VkSurfaceCapabilityPropertiesKHR to VkSurfacePropertiesKHR to better convey the mutable nature of the info it contains.

- Revision 12, 2015-05-28 (James Jones)

  - Added issue 11 with a proposed resolution, and the related issue 12.

  - Updated various sections of the spec to match the proposed resolution to issue 11.

- Revision 13, 2015-06-01 (James Jones)

  - Moved some structures to VK_EXT_KHR_swap_chain to resolve the spec’s issues 1 and 2.

- Revision 14, 2015-06-01 (James Jones)

  - Added code for example 4 demonstrating how an application might make use of the two different present and acquire next image KHR result codes.

  - Added issue 13.

- Revision 15, 2015-06-01 (James Jones)

  - Added issues 14 - 16 and related spec language.

  - Fixed some spelling errors.

  - Added language describing the meaningful return values for vkAcquireNextImageKHR and vkQueuePresentKHR.

- Revision 16, 2015-06-02 (James Jones)

  - Added issues 17 and 18, as well as related spec language.

  - Removed some erroneous text added by mistake in the last update.

- Revision 17, 2015-06-15 (Ian Elliott)

  - Changed special value from "-1" to "0" so that the data types can be unsigned.

- Revision 18, 2015-06-15 (Ian Elliott)

  - Clarified the values of VkSurfacePropertiesKHR::minImageCount and the timeout parameter of the vkAcquireNextImageKHR function.

- Revision 19, 2015-06-17 (James Jones)

  - Misc. cleanup. Removed resolved inline issues and fixed typos.

  - Fixed clarification of VkSurfacePropertiesKHR::minImageCount made in version 18.

  - Added a brief "Image Ownership" definition to the list of terms used in the spec.

- Revision 20, 2015-06-17 (James Jones)

  - Updated enum-extending values using new convention.

- Revision 21, 2015-06-17 (James Jones)

  - Added language describing how to use VK_IMAGE_LAYOUT_PRESENT_SOURCE_KHR.

  - Cleaned up an XXX comment regarding the description of which queues vkQueuePresentKHR can be used on.

- Revision 22, 2015-06-17 (James Jones)

  - Rebased on Vulkan API version 126.

- Revision 23, 2015-06-18 (James Jones)

  - Updated language for issue 12 to read as a proposed resolution.

  - Marked issues 11, 12, 13, 16, and 17 resolved.

  - Temporarily added links to the relevant bugs under the remaining unresolved issues.

  - Added issues 19 and 20 as well as proposed resolutions.

- Revision 24, 2015-06-19 (Ian Elliott)

  - Changed special value for VkSurfacePropertiesKHR::currentExtent back to "-1" from "0". This value will never need to be unsigned, and "0" is actually a legal value.

- Revision 25, 2015-06-23 (Ian Elliott)

  - Examples now show use of function pointers for extension functions.

  - Eliminated extraneous whitespace.

- Revision 26, 2015-06-25 (Ian Elliott)

  - Resolved Issues 9 & 10 per KHR TSG meeting.

- Revision 27, 2015-06-25 (James Jones)

  - Added oldSwapchain member to VkSwapchainCreateInfoKHR.

- Revision 28, 2015-06-25 (James Jones)

  - Added the "inherit" bits to the rotation and mirroring flags and the associated issue 21.

- Revision 29, 2015-06-25 (James Jones)

  - Added the "clipped" flag to VkSwapchainCreateInfoKHR, and the associated issue 22.

  - Specified that presenting an image does not modify it.

- Revision 30, 2015-06-25 (James Jones)

  - Added language to the spec that clarifies the behavior of vkCreateSwapchainKHR() when the oldSwapchain field of VkSwapchainCreateInfoKHR is not NULL.

- Revision 31, 2015-06-26 (Ian Elliott)

  - Example of new VkSwapchainCreateInfoKHR members, "oldSwapchain" and "clipped".

  - Example of using VkSurfacePropertiesKHR::{min|max}ImageCount to set VkSwapchainCreateInfoKHR::minImageCount.

  - Rename vkGetSurfaceInfoKHR()'s 4th parameter to "pDataSize", for consistency with other functions.

  - Add macro with C-string name of extension (just to header file).

- Revision 32, 2015-06-26 (James Jones)

  - Minor adjustments to the language describing the behavior of "oldSwapchain"

  - Fixed the version date on my previous two updates.

- Revision 33, 2015-06-26 (Jesse Hall)

  - Add usage flags to VkSwapchainCreateInfoKHR

- Revision 34, 2015-06-26 (Ian Elliott)

  - Rename vkQueuePresentKHR()'s 2nd parameter to "pPresentInfo", for consistency with other functions.

- Revision 35, 2015-06-26 (Jason Ekstrand)

  - Merged the VkRotationFlagBitsKHR and VkMirrorFlagBitsKHR enums into a single VkSurfaceTransformFlagBitsKHR enum.

- Revision 36, 2015-06-26 (Jason Ekstrand)

  - Added a VkSurfaceTransformKHR enum that is not a bitmask. Each value in VkSurfaceTransformKHR corresponds directly to one of the bits in VkSurfaceTransformFlagBitsKHR so transforming from one to the other is easy. Having a separate enum means that currentTransform and preTransform are now unambiguous by definition.

- Revision 37, 2015-06-29 (Ian Elliott)

  - Corrected one of the signatures of vkAcquireNextImageKHR, which had the last two parameters switched from what it is elsewhere in the specification and header files.

- Revision 38, 2015-06-30 (Ian Elliott)

  - Corrected a typo in description of the vkGetSwapchainInfoKHR() function.

  - Corrected a typo in header file comment for VkPresentInfoKHR::sType.

- Revision 39, 2015-07-07 (Daniel Rakos)

  - Added error section describing when each error is expected to be reported.

  - Replaced bool32_t with VkBool32.

- Revision 40, 2015-07-10 (Ian Elliott)

  - Updated to work with version 138 of the "vulkan.h" header. This includes declaring the VkSwapchainKHR type using the new VK_DEFINE_NONDISP_HANDLE macro, and no longer extending VkObjectType (which was eliminated).

- Revision 41 2015-07-09 (Mathias Heyer)

  - Added color space language.

- Revision 42, 2015-07-10 (Daniel Rakos)

  - Updated query mechanism to reflect the convention changes done in the core spec.

  - Removed "queue" from the name of VK_STRUCTURE_TYPE_QUEUE_PRESENT_INFO_KHR to be consistent with the established naming convention.

  - Removed reference to the no longer existing VkObjectType enum.

- Revision 43, 2015-07-17 (Daniel Rakos)

  - Added support for concurrent sharing of swapchain images across queue families.

  - Updated sample code based on recent changes

- Revision 44, 2015-07-27 (Ian Elliott)

  - Noted that support for VK_PRESENT_MODE_FIFO_KHR is required. That is ICDs may optionally support IMMEDIATE and MAILBOX, but must support FIFO.

- Revision 45, 2015-08-07 (Ian Elliott)

  - Corrected a typo in spec file (type and variable name had wrong case for the imageColorSpace member of the VkSwapchainCreateInfoKHR struct).

  - Corrected a typo in header file (last parameter in PFN_vkGetSurfacePropertiesKHR was missing "KHR" at the end of type: VkSurfacePropertiesKHR).

- Revision 46, 2015-08-20 (Ian Elliott)

  - Renamed this extension and all of its enumerations, types, functions, etc. This makes it compliant with the proposed standard for Vulkan extensions.

  - Switched from "revision" to "version", including use of the VK_MAKE_VERSION macro in the header file.

  - Made improvements to several descriptions.

  - Changed the status of several issues from PROPOSED to RESOLVED, leaving no unresolved issues.

  - Resolved several TODOs, did miscellaneous cleanup, etc.

- Revision 47, 2015-08-20 (Ian Elliott—​porting a 2015-07-29 change from James Jones)

  - Moved the surface transform enums to VK_WSI_swapchain so they could be re-used by VK_WSI_display.

- Revision 48, 2015-09-01 (James Jones)

  - Various minor cleanups.

- Revision 49, 2015-09-01 (James Jones)

  - Restore single-field revision number.

- Revision 50, 2015-09-01 (James Jones)

  - Update Example #4 to include code that illustrates how to use the oldSwapchain field.

- Revision 51, 2015-09-01 (James Jones)

  - Fix example code compilation errors.

- Revision 52, 2015-09-08 (Matthaeus G. Chajdas)

  - Corrected a typo.

- Revision 53, 2015-09-10 (Alon Or-bach)

  - Removed underscore from SWAP_CHAIN left in VK_STRUCTURE_TYPE_SWAPCHAIN_CREATE_INFO_KHR.

- Revision 54, 2015-09-11 (Jesse Hall)

  - Described the execution and memory coherence requirements for image transitions to and from VK_IMAGE_LAYOUT_PRESENT_SOURCE_KHR.

- Revision 55, 2015-09-11 (Ray Smith)

  - Added errors for destroying and binding memory to presentable images

- Revision 56, 2015-09-18 (James Jones)

  - Added fence argument to vkAcquireNextImageKHR

  - Added example of how to meter a host thread based on presentation rate.

- Revision 57, 2015-09-26 (Jesse Hall)

  - Replace VkSurfaceDescriptionKHR with VkSurfaceKHR.

  - Added issue 25 with agreed resolution.

- Revision 58, 2015-09-28 (Jesse Hall)

  - Renamed from VK_EXT_KHR_device_swapchain to VK_EXT_KHR_swapchain.

- Revision 59, 2015-09-29 (Ian Elliott)

  - Changed vkDestroySwapchainKHR() to return void.

- Revision 60, 2015-10-01 (Jeff Vigil)

  - Added error result VK_ERROR_SURFACE_LOST_KHR.

- Revision 61, 2015-10-05 (Jason Ekstrand)

  - Added the VkCompositeAlpha enum and corresponding structure fields.

- Revision 62, 2015-10-12 (Daniel Rakos)

  - Added VK_PRESENT_MODE_FIFO_RELAXED_KHR.

- Revision 63, 2015-10-15 (Daniel Rakos)

  - Moved surface capability queries to VK_EXT_KHR_surface.

- Revision 64, 2015-10-26 (Ian Elliott)

  - Renamed from VK_EXT_KHR_swapchain to VK_KHR_swapchain.

- Revision 65, 2015-10-28 (Ian Elliott)

  - Added optional pResult member to VkPresentInfoKHR, so that per-swapchain results can be obtained from vkQueuePresentKHR().

- Revision 66, 2015-11-03 (Daniel Rakos)

  - Added allocation callbacks to create and destroy functions.

  - Updated resource transition language.

  - Updated sample code.

- Revision 67, 2015-11-10 (Jesse Hall)

  - Add reserved flags bitmask to VkSwapchainCreateInfoKHR.

  - Modify naming and member ordering to match API style conventions, and so the VkSwapchainCreateInfoKHR image property members mirror corresponding VkImageCreateInfo members but with an 'image' prefix.

  - Make VkPresentInfoKHR::pResults non-const; it is an output array parameter.

  - Make pPresentInfo parameter to vkQueuePresentKHR const.

- Revision 68, 2016-04-05 (Ian Elliott)

  - Moved the "validity" include for vkAcquireNextImage to be in its proper place, after the prototype and list of parameters.

  - Clarified language about presentable images, including how they are acquired, when applications can and cannot use them, etc. As part of this, removed language about "ownership" of presentable images, and replaced it with more-consistent language about presentable images being "acquired" by the application.

- 2016-08-23 (Ian Elliott)

  - Update the example code, to use the final API command names, to not have so many characters per line, and to split out a new example to show how to obtain function pointers. This code is more similar to the LunarG "cube" demo program.

- 2016-08-25 (Ian Elliott)

  - A note was added at the beginning of the example code, stating that it will be removed from future versions of the appendix.

- Revision 69, 2017-09-07 (Tobias Hector)

  - Added interactions with Vulkan 1.1

- Revision 70, 2017-10-06 (Ian Elliott)

  - Corrected interactions with Vulkan 1.1

#### VK_KHR_swapchain_mutable_format

Name String

  `VK_KHR_swapchain_mutable_format`

Extension Type

  Device extension

Registered Extension Number

  201

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_swapchain`

  - Requires `VK_KHR_maintenance2`

  - Requires `VK_KHR_image_format_list`

Contact

  - Daniel Rakos drakos-arm

Last Modified Date

  2018-03-28

IP Status

  No known IP claims.

Contributors

  - Jason Ekstrand, Intel

  - Jan-Harald Fredriksen, ARM

  - Jesse Hall, Google

  - Daniel Rakos, AMD

  - Ray Smith, ARM

#### Short Description

Allows processing of swapchain images as different formats to that used by the window system, which is particularly useful for switching between sRGB and linear RGB formats.

#### Description

This extension adds a new swapchain creation flag that enables creating image views from presentable images with a different format than the one used to create the swapchain.

#### New Object Types

None.

#### New Enum Constants

- Extending VkSwapchainCreateFlagBitsKHR:

  - `VK_SWAPCHAIN_CREATE_MUTABLE_FORMAT_BIT_KHR`

#### New Enums

None.

#### New Structures

None.

#### New Functions

None.

#### Issues

1) Are there any new capabilities needed?

RESOLVED: No. It is expected that all implementations exposing this extension support swapchain image format mutability.

2) Do we need a separate `VK_SWAPCHAIN_CREATE_EXTENDED_USAGE_BIT_KHR`?

RESOLVED: No. This extension requires `VK_KHR_maintenance2` and presentable images of swapchains created with `VK_SWAPCHAIN_CREATE_MUTABLE_FORMAT_BIT_KHR` are created internally in a way equivalent to specifying both `VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT` and `VK_IMAGE_CREATE_EXTENDED_USAGE_BIT_KHR`.

3) Do we need a separate structure to allow specifying an image format list for swapchains?

RESOLVED: No. We simply use the same VkImageFormatListCreateInfoKHR structure introduced by `VK_KHR_image_format_list`. The structure is required to be included in the `pNext` chain of VkSwapchainCreateInfoKHR for swapchains created with `VK_SWAPCHAIN_CREATE_MUTABLE_FORMAT_BIT_KHR`.

#### Version History

- Revision 1, 2018-03-28 (Daniel Rakos)

  - Internal revisions.

#### VK_KHR_wayland_surface

Name String

  `VK_KHR_wayland_surface`

Extension Type

  Instance extension

Registered Extension Number

  7

Revision

  6

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_surface`

Contact

  - Jesse Hall critsec

  - Ian Elliott ianelliottus

Last Modified Date

  2015-11-28

IP Status

  No known IP claims.

Contributors

  - Patrick Doane, Blizzard

  - Jason Ekstrand, Intel

  - Ian Elliott, LunarG

  - Courtney Goeltzenleuchter, LunarG

  - Jesse Hall, Google

  - James Jones, NVIDIA

  - Antoine Labour, Google

  - Jon Leech, Khronos

  - David Mao, AMD

  - Norbert Nopper, Freescale

  - Alon Or-bach, Samsung

  - Daniel Rakos, AMD

  - Graham Sellers, AMD

  - Ray Smith, ARM

  - Jeff Vigil, Qualcomm

  - Chia-I Wu, LunarG

The `VK_KHR_wayland_surface` extension is an instance extension. It provides a mechanism to create a VkSurfaceKHR object (defined by the `VK_KHR_surface` extension) that refers to a Wayland `wl_surface`, as well as a query to determine support for rendering to a Wayland compositor.

#### New Object Types

None

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_WAYLAND_SURFACE_CREATE_INFO_KHR`

#### New Enums

None

#### New Structures

- VkWaylandSurfaceCreateInfoKHR

#### New Functions

- vkCreateWaylandSurfaceKHR

- vkGetPhysicalDeviceWaylandPresentationSupportKHR

#### Issues

1) Does Wayland need a way to query for compatibility between a particular physical device and a specific Wayland display? This would be a more general query than vkGetPhysicalDeviceSurfaceSupportKHR: if the Wayland-specific query returned `VK_TRUE` for a (VkPhysicalDevice, `struct wl_display*`) pair, then the physical device could be assumed to support presentation to any VkSurfaceKHR for surfaces on the display.

RESOLVED: Yes. vkGetPhysicalDeviceWaylandPresentationSupportKHR was added to address this issue.

2) Should we require surfaces created with vkCreateWaylandSurfaceKHR to support the `VK_PRESENT_MODE_MAILBOX_KHR` present mode?

RESOLVED: Yes. Wayland is an inherently mailbox window system and mailbox support is required for some Wayland compositor interactions to work as expected. While handling these interactions may be possible with `VK_PRESENT_MODE_FIFO_KHR`, it is much more difficult to do without deadlock and requiring all Wayland applications to be able to support implementations which only support `VK_PRESENT_MODE_FIFO_KHR` would be an onerous restriction on application developers.

#### Version History

- Revision 1, 2015-09-23 (Jesse Hall)

  - Initial draft, based on the previous contents of VK_EXT_KHR_swapchain (later renamed VK_EXT_KHR_surface).

- Revision 2, 2015-10-02 (James Jones)

  - Added vkGetPhysicalDeviceWaylandPresentationSupportKHR() to resolve issue #1.

  - Adjusted wording of issue #1 to match the agreed-upon solution.

  - Renamed "window" parameters to "surface" to match Wayland conventions.

- Revision 3, 2015-10-26 (Ian Elliott)

  - Renamed from VK_EXT_KHR_wayland_surface to VK_KHR_wayland_surface.

- Revision 4, 2015-11-03 (Daniel Rakos)

  - Added allocation callbacks to vkCreateWaylandSurfaceKHR.

- Revision 5, 2015-11-28 (Daniel Rakos)

  - Updated the surface create function to take a pCreateInfo structure.

- Revision 6, 2017-02-08 (Jason Ekstrand)

  - Added the requirement that implementations support `VK_PRESENT_MODE_MAILBOX_KHR`.

  - Added wording about interactions between vkQueuePresentKHR and the Wayland requests sent to the compositor.

#### VK_KHR_win32_keyed_mutex

Name String

  `VK_KHR_win32_keyed_mutex`

Extension Type

  Device extension

Registered Extension Number

  76

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_external_memory_win32`

Contact

  - Carsten Rohde crohde

Last Modified Date

  2016-10-21

IP Status

  No known IP claims.

Contributors

  - James Jones, NVIDIA

  - Jeff Juliano, NVIDIA

  - Carsten Rohde, NVIDIA

Applications that wish to import Direct3D 11 memory objects into the Vulkan API may wish to use the native keyed mutex mechanism to synchronize access to the memory between Vulkan and Direct3D. This extension provides a way for an application to access the keyed mutex associated with an imported Vulkan memory object when submitting command buffers to a queue.

#### New Object Types

None.

#### New Enum Constants

- `VK_STRUCTURE_TYPE_WIN32_KEYED_MUTEX_ACQUIRE_RELEASE_INFO_KHR`

#### New Enums

None.

#### New Structs

- VkWin32KeyedMutexAcquireReleaseInfoKHR

#### New Functions

None.

#### Issues

None.

#### Version History

- Revision 1, 2016-10-21 (James Jones)

  - Initial revision

#### VK_KHR_win32_surface

Name String

  `VK_KHR_win32_surface`

Extension Type

  Instance extension

Registered Extension Number

  10

Revision

  6

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_surface`

Contact

  - Jesse Hall critsec

  - Ian Elliott ianelliottus

Last Modified Date

  2017-04-24

IP Status

  No known IP claims.

Contributors

  - Patrick Doane, Blizzard

  - Jason Ekstrand, Intel

  - Ian Elliott, LunarG

  - Courtney Goeltzenleuchter, LunarG

  - Jesse Hall, Google

  - James Jones, NVIDIA

  - Antoine Labour, Google

  - Jon Leech, Khronos

  - David Mao, AMD

  - Norbert Nopper, Freescale

  - Alon Or-bach, Samsung

  - Daniel Rakos, AMD

  - Graham Sellers, AMD

  - Ray Smith, ARM

  - Jeff Vigil, Qualcomm

  - Chia-I Wu, LunarG

The `VK_KHR_win32_surface` extension is an instance extension. It provides a mechanism to create a VkSurfaceKHR object (defined by the `VK_KHR_surface` extension) that refers to a Win32 `HWND`, as well as a query to determine support for rendering to the windows desktop.

#### New Object Types

None

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_WIN32_SURFACE_CREATE_INFO_KHR`

#### New Enums

None

#### New Structures

- VkWin32SurfaceCreateInfoKHR

#### New Functions

- vkCreateWin32SurfaceKHR

- vkGetPhysicalDeviceWin32PresentationSupportKHR

#### Issues

1) Does Win32 need a way to query for compatibility between a particular physical device and a specific screen? Compatibility between a physical device and a window generally only depends on what screen the window is on. However, there is not an obvious way to identify a screen without already having a window on the screen.

RESOLVED: No. While it may be useful, there is not a clear way to do this on Win32. However, a method was added to query support for presenting to the windows desktop as a whole.

2) If a native window object (`HWND`) is used by one graphics API, and then is later used by a different graphics API (one of which is Vulkan), can these uses interfere with each other?

RESOLVED: Yes.

Uses of a window object by multiple graphics APIs results in undefined behavior. Such behavior may succeed when using one Vulkan implementation but fail when using a different Vulkan implementation. Potential failures include:

- Creating then destroying a flip presentation model DXGI swapchain on a window object can prevent vkCreateSwapchainKHR from succeeding on the same window object.

- Creating then destroying a VkSwapchainKHR on a window object can prevent creation of a bitblt model DXGI swapchain on the same window object.

- Creating then destroying a VkSwapchainKHR on a window object can effectively `SetPixelFormat` to a different format than the format chosen by an OpenGL application.

- Creating then destroying a VkSwapchainKHR on a window object on one VkPhysicalDevice can prevent vkCreateSwapchainKHR from succeeding on the same window object, but on a different VkPhysicalDevice that is associated with a different Vulkan ICD.

In all cases the problem can be worked around by creating a new window object.

Technical details include:

- Creating a DXGI swapchain over a window object can alter the object for the remainder of its lifetime. The alteration persists even after the DXGI swapchain has been destroyed. This alteration can make it impossible for a conformant Vulkan implementation to create a VkSwapchainKHR over the same window object. Mention of this alteration can be found in the remarks section of the MSDN documentation for `DXGI_SWAP_EFFECT`.

- Calling GDI’s `SetPixelFormat` (needed by OpenGL’s WGL layer) on a window object alters the object for the remainder of its lifetime. The MSDN documentation for `SetPixelFormat` explains that a window object’s pixel format can be set only one time.

- Creating a VkSwapchainKHR over a window object can alter the object for the remaining life of its lifetime. Either of the above alterations may occur as a side-effect of VkSwapchainKHR.

#### Version History

- Revision 1, 2015-09-23 (Jesse Hall)

  - Initial draft, based on the previous contents of VK_EXT_KHR_swapchain (later renamed VK_EXT_KHR_surface).

- Revision 2, 2015-10-02 (James Jones)

  - Added presentation support query for win32 desktops.

- Revision 3, 2015-10-26 (Ian Elliott)

  - Renamed from VK_EXT_KHR_win32_surface to VK_KHR_win32_surface.

- Revision 4, 2015-11-03 (Daniel Rakos)

  - Added allocation callbacks to vkCreateWin32SurfaceKHR.

- Revision 5, 2015-11-28 (Daniel Rakos)

  - Updated the surface create function to take a pCreateInfo structure.

- Revision 6, 2017-04-24 (Jeff Juliano)

  - Add issue 2 addressing reuse of a native window object in a different Graphics API, or by a different Vulkan ICD.

#### VK_KHR_xcb_surface

Name String

  `VK_KHR_xcb_surface`

Extension Type

  Instance extension

Registered Extension Number

  6

Revision

  6

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_surface`

Contact

  - Jesse Hall critsec

  - Ian Elliott ianelliottus

Last Modified Date

  2015-11-28

IP Status

  No known IP claims.

Contributors

  - Patrick Doane, Blizzard

  - Jason Ekstrand, Intel

  - Ian Elliott, LunarG

  - Courtney Goeltzenleuchter, LunarG

  - Jesse Hall, Google

  - James Jones, NVIDIA

  - Antoine Labour, Google

  - Jon Leech, Khronos

  - David Mao, AMD

  - Norbert Nopper, Freescale

  - Alon Or-bach, Samsung

  - Daniel Rakos, AMD

  - Graham Sellers, AMD

  - Ray Smith, ARM

  - Jeff Vigil, Qualcomm

  - Chia-I Wu, LunarG

The `VK_KHR_xcb_surface` extension is an instance extension. It provides a mechanism to create a VkSurfaceKHR object (defined by the `VK_KHR_surface` extension) that refers to an X11 `Window`, using the XCB client-side library, as well as a query to determine support for rendering via XCB.

#### New Object Types

None

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_XCB_SURFACE_CREATE_INFO_KHR`

#### New Enums

None

#### New Structures

- VkXcbSurfaceCreateInfoKHR

#### New Functions

- vkCreateXcbSurfaceKHR

- vkGetPhysicalDeviceXcbPresentationSupportKHR

#### Issues

1) Does XCB need a way to query for compatibility between a particular physical device and a specific screen? This would be a more general query than vkGetPhysicalDeviceSurfaceSupportKHR: If it returned `VK_TRUE`, then the physical device could be assumed to support presentation to any window on that screen.

RESOLVED: Yes, this is needed for toolkits that want to create a VkDevice before creating a window. To ensure the query is reliable, it must be made against a particular X visual rather than the screen in general.

#### Version History

- Revision 1, 2015-09-23 (Jesse Hall)

  - Initial draft, based on the previous contents of VK_EXT_KHR_swapchain (later renamed VK_EXT_KHR_surface).

- Revision 2, 2015-10-02 (James Jones)

  - Added presentation support query for an (xcb_connection_t*, xcb_visualid_t) pair.

  - Removed "root" parameter from CreateXcbSurfaceKHR(), as it is redundant when a window on the same screen is specified as well.

  - Adjusted wording of issue #1 and added agreed upon resolution.

- Revision 3, 2015-10-14 (Ian Elliott)

  - Removed "root" parameter from CreateXcbSurfaceKHR() in one more place.

- Revision 4, 2015-10-26 (Ian Elliott)

  - Renamed from VK_EXT_KHR_xcb_surface to VK_KHR_xcb_surface.

- Revision 5, 2015-10-23 (Daniel Rakos)

  - Added allocation callbacks to vkCreateXcbSurfaceKHR.

- Revision 6, 2015-11-28 (Daniel Rakos)

  - Updated the surface create function to take a pCreateInfo structure.

#### VK_KHR_xlib_surface

Name String

  `VK_KHR_xlib_surface`

Extension Type

  Instance extension

Registered Extension Number

  5

Revision

  6

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_surface`

Contact

  - Jesse Hall critsec

  - Ian Elliott ianelliottus

Last Modified Date

  2015-11-28

IP Status

  No known IP claims.

Contributors

  - Patrick Doane, Blizzard

  - Jason Ekstrand, Intel

  - Ian Elliott, LunarG

  - Courtney Goeltzenleuchter, LunarG

  - Jesse Hall, Google

  - James Jones, NVIDIA

  - Antoine Labour, Google

  - Jon Leech, Khronos

  - David Mao, AMD

  - Norbert Nopper, Freescale

  - Alon Or-bach, Samsung

  - Daniel Rakos, AMD

  - Graham Sellers, AMD

  - Ray Smith, ARM

  - Jeff Vigil, Qualcomm

  - Chia-I Wu, LunarG

The `VK_KHR_xlib_surface` extension is an instance extension. It provides a mechanism to create a VkSurfaceKHR object (defined by the `VK_KHR_surface` extension) that refers to an X11 `Window`, using the Xlib client-side library, as well as a query to determine support for rendering via Xlib.

#### New Object Types

None

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_XLIB_SURFACE_CREATE_INFO_KHR`

#### New Enums

None

#### New Structures

- VkXlibSurfaceCreateInfoKHR

#### New Functions

- vkCreateXlibSurfaceKHR

- vkGetPhysicalDeviceXlibPresentationSupportKHR

#### Issues

1) Does X11 need a way to query for compatibility between a particular physical device and a specific screen? This would be a more general query than vkGetPhysicalDeviceSurfaceSupportKHR; if it returned `VK_TRUE`, then the physical device could be assumed to support presentation to any window on that screen.

RESOLVED: Yes, this is needed for toolkits that want to create a VkDevice before creating a window. To ensure the query is reliable, it must be made against a particular X visual rather than the screen in general.

#### Version History

- Revision 1, 2015-09-23 (Jesse Hall)

  - Initial draft, based on the previous contents of VK_EXT_KHR_swapchain (later renamed VK_EXT_KHR_surface).

- Revision 2, 2015-10-02 (James Jones)

  - Added presentation support query for (Display*, VisualID) pair.

  - Removed "root" parameter from CreateXlibSurfaceKHR(), as it is redundant when a window on the same screen is specified as well.

  - Added appropriate X errors.

  - Adjusted wording of issue #1 and added agreed upon resolution.

- Revision 3, 2015-10-14 (Ian Elliott)

  - Renamed this extension from VK_EXT_KHR_x11_surface to VK_EXT_KHR_xlib_surface.

- Revision 4, 2015-10-26 (Ian Elliott)

  - Renamed from VK_EXT_KHR_xlib_surface to VK_KHR_xlib_surface.

- Revision 5, 2015-11-03 (Daniel Rakos)

  - Added allocation callbacks to vkCreateXlibSurfaceKHR.

- Revision 6, 2015-11-28 (Daniel Rakos)

  - Updated the surface create function to take a pCreateInfo structure.

#### VK_EXT_acquire_xlib_display

Name String

  `VK_EXT_acquire_xlib_display`

Extension Type

  Instance extension

Registered Extension Number

  90

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_EXT_direct_mode_display`

Contact

  - James Jones cubanismo

Last Modified Date

  2016-12-13

IP Status

  No known IP claims.

Contributors

  - Dave Airlie, Red Hat

  - Pierre Boudier, NVIDIA

  - James Jones, NVIDIA

  - Damien Leone, NVIDIA

  - Pierre-Loup Griffais, Valve

  - Liam Middlebrook, NVIDIA

  - Daniel Vetter, Intel

This extension allows an application to take exclusive control on a display currently associated with an X11 screen. When control is acquired, the display will be deassociated from the X11 screen until control is released or the specified display connection is closed. Essentially, the X11 screen will behave as if the monitor has been unplugged until control is released.

#### New Enum Constants

None.

#### New Enums

None.

#### New Structures

None.

#### New Functions

- vkAcquireXlibDisplayEXT

- vkGetRandROutputDisplayEXT

#### Issues

1) Should vkAcquireXlibDisplayEXT take an RandR display ID, or a Vulkan display handle as input?

RESOLVED: A Vulkan display handle. Otherwise there would be no way to specify handles to displays that had been “blacklisted” or prevented from being included in the X11 display list by some native platform or vendor-specific mechanism.

2) How does an application figure out which RandR display corresponds to a Vulkan display?

RESOLVED: A new function, vkGetRandROutputDisplayEXT, is introduced for this purpose.

3) Should vkGetRandROutputDisplayEXT be part of this extension, or a general Vulkan / RandR or Vulkan / Xlib extension?

RESOLVED: To avoid yet another extension, include it in this extension.

#### Version History

- Revision 1, 2016-12-13 (James Jones)

  - Initial draft

#### VK_EXT_astc_decode_mode

Name String

  `VK_EXT_astc_decode_mode`

Extension Type

  Device extension

Registered Extension Number

  68

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Jan-Harald Fredriksen janharaldfredriksen-arm

Last Modified Date

  2018-08-07

Contributors

  - Jan-Harald Fredriksen, Arm

The existing specification requires that low dynamic range (LDR) ASTC textures are decompressed to FP16 values per component. In many cases, decompressing LDR textures to a lower precision intermediate result gives acceptable image quality. Source material for LDR textures is typically authored as 8-bit UNORM values, so decoding to FP16 values adds little value. On the other hand, reducing precision of the decoded result reduces the size of the decompressed data, potentially improving texture cache performance and saving power.

The goal of this extension is to enable this efficiency gain on existing ASTC texture data. This is achieved by giving the application the ability to select the intermediate decoding precision.

Three decoding options are provided:

- Decode to `VK_FORMAT_R16G16B16A16_SFLOAT` precision: This is the default, and matches the required behavior in the core API.

- Decode to `VK_FORMAT_R8G8B8A8_UNORM` precision: This is provided as an option in LDR mode.

- Decode to `VK_FORMAT_E5B9G9R9_UFLOAT_PACK32` precision: This is provided as an option in both LDR and HDR mode. In this mode, negative values cannot be represented and are clamped to zero. The alpha component is ignored, and the results are as if alpha was 1.0. This decode mode is optional and support can be queried via the physical device properties.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_IMAGE_VIEW_ASTC_DECODE_MODE_EXT`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_ASTC_DECODE_FEATURES_EXT`

#### New Enums

None.

#### New Structures

- VkImageViewASTCDecodeModeEXT

- VkPhysicalDeviceASTCDecodeFeaturesEXT

#### New Functions

None.

#### Issues

1) Are implementations allowed to decode at a higher precision than what is requested?

    RESOLUTION: No.
    If we allow this, then this extension could be exposed on all
    implementations that support ASTC.
    But developers would have no way of knowing what precision was actually
    used, and thus whether the image quality is sufficient at reduced
    precision.

2) Should the decode mode be image view state and/or sampler state?

    RESOLUTION: Image view state only.
    Some implementations treat the different decode modes as different
    texture formats.

#### Example

Create an image view that decodes to `VK_FORMAT_R8G8B8A8_UNORM` precision:

        VkImageViewASTCDecodeModeEXT decodeMode =
        {
            VK_STRUCTURE_TYPE_IMAGE_VIEW_ASTC_DECODE_MODE_EXT, // sType
            NULL, // pNext
            VK_FORMAT_R8G8B8A8_UNORM // decode mode
        };

        VkImageViewCreateInfo createInfo =
        {
            VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO, // sType
            &decodeMode, // pNext
            // flags, image, viewType set to application-desired values
            VK_FORMAT_ASTC_8x8_UNORM_BLOCK, // format
            // components, subresourceRange set to application-desired values
        };

        VkImageView imageView;
        VkResult result = vkCreateImageView(
            device,
            &createInfo,
            NULL,
            &imageView);

#### Version History

- Revision 1, 2018-08-07 (Jan-Harald Fredriksen)

  - Initial revision

#### VK_EXT_blend_operation_advanced

Name String

  `VK_EXT_blend_operation_advanced`

Extension Type

  Device extension

Registered Extension Number

  149

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Jeff Bolz jeffbolznv

Last Modified Date

  2017-06-12

Contributors

  - Jeff Bolz, NVIDIA

This extension adds a number of “advanced” blending operations that can be used to perform new color blending operations, many of which are more complex than the standard blend modes provided by unextended Vulkan. This extension requires different styles of usage, depending on the level of hardware support and the enabled features:

- If VkPhysicalDeviceBlendOperationAdvancedFeaturesEXT::`advancedBlendCoherentOperations` is `VK_FALSE`, the new blending operations are supported, but a memory dependency must separate each advanced blend operation on a given sample. `VK_ACCESS_COLOR_ATTACHMENT_READ_NONCOHERENT_BIT_EXT` is used to synchronize reads using advanced blend operations.

- If VkPhysicalDeviceBlendOperationAdvancedFeaturesEXT::`advancedBlendCoherentOperations` is `VK_TRUE`, advanced blend operations obey primitive order just like basic blend operations.

In unextended Vulkan, the set of blending operations is limited, and can be expressed very simply. The `VK_BLEND_OP_MIN` and `VK_BLEND_OP_MAX` blend operations simply compute component-wise minimums or maximums of source and destination color components. The `VK_BLEND_OP_ADD`, `VK_BLEND_OP_SUBTRACT`, and `VK_BLEND_OP_REVERSE_SUBTRACT` modes multiply the source and destination colors by source and destination factors and either add the two products together or subtract one from the other. This limited set of operations supports many common blending operations but precludes the use of more sophisticated transparency and blending operations commonly available in many dedicated imaging APIs.

This extension provides a number of new “advanced” blending operations. Unlike traditional blending operations using `VK_BLEND_OP_ADD`, these blending equations do not use source and destination factors specified by VkBlendFactor. Instead, each blend operation specifies a complete equation based on the source and destination colors. These new blend operations are used for both RGB and alpha components; they must not be used to perform separate RGB and alpha blending (via different values of color and alpha VkBlendOp).

These blending operations are performed using premultiplied colors, where RGB colors can be considered premultiplied or non-premultiplied by alpha, according to the `srcPremultiplied` and `dstPremultiplied` members of VkPipelineColorBlendAdvancedStateCreateInfoEXT. If a color is considered non-premultiplied, the (R,G,B) color components are multiplied by the alpha component prior to blending. For non-premultiplied color components in the range [0,1], the corresponding premultiplied color component would have values in the range [0 × A, 1 × A].

Many of these advanced blending equations are formulated where the result of blending source and destination colors with partial coverage have three separate contributions: from the portions covered by both the source and the destination, from the portion covered only by the source, and from the portion covered only by the destination. The blend parameter VkPipelineColorBlendAdvancedStateCreateInfoEXT::`blendOverlap` can be used to specify a correlation between source and destination pixel coverage. If set to `VK_BLEND_OVERLAP_CONJOINT_EXT`, the source and destination are considered to have maximal overlap, as would be the case if drawing two objects on top of each other. If set to `VK_BLEND_OVERLAP_DISJOINT_EXT`, the source and destination are considered to have minimal overlap, as would be the case when rendering a complex polygon tessellated into individual non-intersecting triangles. If set to `VK_BLEND_OVERLAP_UNCORRELATED_EXT`, the source and destination coverage are assumed to have no spatial correlation within the pixel.

In addition to the coherency issues on implementations not supporting `advancedBlendCoherentOperations`, this extension has several limitations worth noting. First, the new blend operations have a limit on the number of color attachments they can be used with, as indicated by VkPhysicalDeviceBlendOperationAdvancedPropertiesEXT::`advancedBlendMaxColorAttachments`. Additionally, blending precision may be limited to 16-bit floating-point, which may result in a loss of precision and dynamic range for framebuffer formats with 32-bit floating-point components, and in a loss of precision for formats with 12- and 16-bit signed or unsigned normalized integer components.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_BLEND_OPERATION_ADVANCED_FEATURES_EXT`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_BLEND_OPERATION_ADVANCED_PROPERTIES_EXT`

  - `VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_ADVANCED_STATE_CREATE_INFO_EXT`

- Extending VkAccessFlagBits:

  - `VK_ACCESS_COLOR_ATTACHMENT_READ_NONCOHERENT_BIT_EXT`

- Extending VkBlendOp:

  - `VK_BLEND_OP_ZERO_EXT`

  - `VK_BLEND_OP_SRC_EXT`

  - `VK_BLEND_OP_DST_EXT`

  - `VK_BLEND_OP_SRC_OVER_EXT`

  - `VK_BLEND_OP_DST_OVER_EXT`

  - `VK_BLEND_OP_SRC_IN_EXT`

  - `VK_BLEND_OP_DST_IN_EXT`

  - `VK_BLEND_OP_SRC_OUT_EXT`

  - `VK_BLEND_OP_DST_OUT_EXT`

  - `VK_BLEND_OP_SRC_ATOP_EXT`

  - `VK_BLEND_OP_DST_ATOP_EXT`

  - `VK_BLEND_OP_XOR_EXT`

  - `VK_BLEND_OP_MULTIPLY_EXT`

  - `VK_BLEND_OP_SCREEN_EXT`

  - `VK_BLEND_OP_OVERLAY_EXT`

  - `VK_BLEND_OP_DARKEN_EXT`

  - `VK_BLEND_OP_LIGHTEN_EXT`

  - `VK_BLEND_OP_COLORDODGE_EXT`

  - `VK_BLEND_OP_COLORBURN_EXT`

  - `VK_BLEND_OP_HARDLIGHT_EXT`

  - `VK_BLEND_OP_SOFTLIGHT_EXT`

  - `VK_BLEND_OP_DIFFERENCE_EXT`

  - `VK_BLEND_OP_EXCLUSION_EXT`

  - `VK_BLEND_OP_INVERT_EXT`

  - `VK_BLEND_OP_INVERT_RGB_EXT`

  - `VK_BLEND_OP_LINEARDODGE_EXT`

  - `VK_BLEND_OP_LINEARBURN_EXT`

  - `VK_BLEND_OP_VIVIDLIGHT_EXT`

  - `VK_BLEND_OP_LINEARLIGHT_EXT`

  - `VK_BLEND_OP_PINLIGHT_EXT`

  - `VK_BLEND_OP_HARDMIX_EXT`

  - `VK_BLEND_OP_HSL_HUE_EXT`

  - `VK_BLEND_OP_HSL_SATURATION_EXT`

  - `VK_BLEND_OP_HSL_COLOR_EXT`

  - `VK_BLEND_OP_HSL_LUMINOSITY_EXT`

  - `VK_BLEND_OP_PLUS_EXT`

  - `VK_BLEND_OP_PLUS_CLAMPED_EXT`

  - `VK_BLEND_OP_PLUS_CLAMPED_ALPHA_EXT`

  - `VK_BLEND_OP_PLUS_DARKER_EXT`

  - `VK_BLEND_OP_MINUS_EXT`

  - `VK_BLEND_OP_MINUS_CLAMPED_EXT`

  - `VK_BLEND_OP_CONTRAST_EXT`

  - `VK_BLEND_OP_INVERT_OVG_EXT`

  - `VK_BLEND_OP_RED_EXT`

  - `VK_BLEND_OP_GREEN_EXT`

  - `VK_BLEND_OP_BLUE_EXT`

#### New Enums

- VkBlendOverlapEXT

#### New Structures

- VkPhysicalDeviceBlendOperationAdvancedFeaturesEXT

- VkPhysicalDeviceBlendOperationAdvancedPropertiesEXT

- VkPipelineColorBlendAdvancedStateCreateInfoEXT

#### New Functions

None.

#### Issues

None.

#### Version History

- Revision 1, 2017-06-12 (Jeff Bolz)

  - Internal revisions

- Revision 2, 2017-06-12 (Jeff Bolz)

  - Internal revisions

#### VK_EXT_calibrated_timestamps

Name String

  `VK_EXT_calibrated_timestamps`

Extension Type

  Device extension

Registered Extension Number

  185

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Daniel Rakos drakos-amd

Last Modified Date

  2018-10-04

IP Status

  No known IP claims.

Contributors

  - Matthaeus G. Chajdas, AMD

  - Alan Harrison, AMD

  - Derrick Owens, AMD

  - Daniel Rakos, AMD

  - Jason Ekstrand, Intel

  - Keith Packard, Valve

This extension provides an interface to query calibrated timestamps obtained quasi simultaneously from two time domains.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_CALIBRATED_TIMESTAMP_INFO_EXT`

#### New Enums

- VkTimeDomainEXT

#### New Structures

- VkCalibratedTimestampInfoEXT

#### New Functions

- vkGetPhysicalDeviceCalibrateableTimeDomainsEXT

- vkGetCalibratedTimestampsEXT

#### Issues

1) Is the device timestamp value returned in the same time domain as the timestamp values written by vkCmdWriteTimestamp?

RESOLVED: Yes.

2) What time domain is the host timestamp returned in?

RESOLVED: A query is provided to determine the calibrateable time domains. The expected host time domain used on Windows is that of QueryPerformanceCounter, and on Linux that of CLOCK_MONOTONIC.

3) Should we support other time domain combinations than just one host and the device time domain?

RESOLVED: Supporting that would need the application to query the set of supported time domains, while supporting only one host and the device time domain would only need a query for the host time domain type. The proposed API chooses the general approach for the sake of extensibility.

4) Shouldn’t we use CLOCK_MONOTONIC_RAW instead of CLOCK_MONOTONIC?

RESOLVED: CLOCK_MONOTONIC is usable in a wider set of situations, however, it is subject to NTP adjustments so some use cases may prefer CLOCK_MONOTONIC_RAW. Thus this extension allows both to be exposed.

5) How can the application extrapolate future device timestamp values from the calibrated timestamp value?

RESOLVED: VkPhysicalDeviceLimits::`timestampPeriod` makes it possible to calculate future device timestamps as follows:

    futureTimestamp = calibratedTimestamp + deltaNanoseconds / timestampPeriod

6) Can the host and device timestamp values drift apart over longer periods of time?

RESOLVED: Yes, especially as some time domains by definition allow for that to happen (e.g. CLOCK_MONOTONIC is subject to NTP adjustments). Thus it’s recommended that applications re-calibrate from time to time.

7) Should we add a query for reporting the maximum deviation of the timestamp values returned by calibrated timestamp queries?

RESOLVED: A global query seems inappropriate and difficult to enforce. However, it’s possible to return the maximum deviation any single calibrated timestamp query can have by sampling one of the time domains twice as follows:

    timestampX = timestampX_before = SampleTimeDomain(X)
    for each time domain Y != X
        timestampY = SampleTimeDomain(Y)
    timestampX_after = SampleTimeDomain(X)
    maxDeviation = timestampX_after - timestampX_before

8) Can the maximum deviation reported ever be zero?

RESOLVED: Unless the tick of each clock corresponding to the set of time domains coincides and all clocks can literally be sampled simutaneously, there isn’t really a possibility for the maximum deviation to be zero, so by convention the maximum deviation is always at least the maximum of the length of the ticks of the set of time domains calibrated and thus can never be zero.

#### Version History

- Revision 1, 2018-10-04 (Daniel Rakos)

  - Internal revisions.

#### VK_EXT_conditional_rendering

Name String

  `VK_EXT_conditional_rendering`

Extension Type

  Device extension

Registered Extension Number

  82

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Vikram Kushwaha vkushwaha

Last Modified Date

  2018-05-21

IP Status

  No known IP claims.

Contributors

  - Vikram Kushwaha, NVIDIA

  - Daniel Rakos, AMD

  - Jesse Hall, Google

  - Jeff Bolz, NVIDIA

  - Piers Daniell, NVIDIA

  - Stuart Smith, Imagination Technologies

This extension allows the execution of one or more rendering commands to be conditional on a value in buffer memory. This may help an application reduce the latency by conditionally discarding rendering commands without application intervention. The conditional rendering commands are limited to draws, compute dispatches and clearing attachments within a conditional rendering block.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_COMMAND_BUFFER_INHERITANCE_CONDITIONAL_RENDERING_INFO_EXT`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_CONDITIONAL_RENDERING_FEATURES_EXT`

  - `VK_STRUCTURE_TYPE_CONDITIONAL_RENDERING_BEGIN_INFO_EXT`

- Extending VkAccessFlagBits:

  - `VK_ACCESS_CONDITIONAL_RENDERING_READ_BIT_EXT`

- Extending VkBufferUsageFlagBits:

  - `VK_BUFFER_USAGE_CONDITIONAL_RENDERING_BIT_EXT`

- Extending VkPipelineStageFlagBits:

  - `VK_PIPELINE_STAGE_CONDITIONAL_RENDERING_BIT_EXT`

#### New Enums

- VkConditionalRenderingFlagBitsEXT

#### New Structures

- VkConditionalRenderingBeginInfoEXT

- Extending VkCommandBufferInheritanceInfo:

  - VkCommandBufferInheritanceConditionalRenderingInfoEXT

- Extending VkPhysicalDeviceFeatures2:

  - VkPhysicalDeviceConditionalRenderingFeaturesEXT

None.

#### New Functions

- vkCmdBeginConditionalRenderingEXT

- vkCmdEndConditionalRenderingEXT

#### Issues

1) Should conditional rendering affect copy and blit commands?

RESOLVED: Conditional rendering should not affect copies and blits.

2) Should secondary command buffers be allowed to execute while conditional rendering is active in the primary command buffer?

RESOLVED: The rendering commands in secondary command buffer will be affected by an active conditional rendering in primary command buffer if the `conditionalRenderingEnable` is set to `VK_TRUE`. Conditional rendering must not be active in the primary command buffer if `conditionalRenderingEnable` is `VK_FALSE`.

#### Examples

None.

#### Version History

- Revision 1, 2018-04-19 (Vikram Kushwaha)

  - First Version

- Revision 2, 2018-05-21 (Vikram Kushwaha)

  - Add new pipeline stage, access flags and limit conditional rendering to a subpass or entire renderpass.

#### VK_EXT_conservative_rasterization

Name String

  `VK_EXT_conservative_rasterization`

Extension Type

  Device extension

Registered Extension Number

  102

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Piers Daniell pdaniell-nv

Last Modified Data

  2017-08-28

Contributors

  - Daniel Koch, NVIDIA

  - Daniel Rakos, AMD

  - Jeff Bolz, NVIDIA

  - Slawomir Grajewski, Intel

  - Stu Smith, Imagination Technologies

This extension adds a new rasterization mode called conservative rasterization. There are two modes of conservative rasterization; overestimation and underestimation.

When overestimation is enabled, if any part of the primitive, including its edges, covers any part of the rectangular pixel area, including its sides, then a fragment is generated with all coverage samples turned on. This extension allows for some variation in implementations by accounting for differences in overestimation, where the generating primitive size is increased at each of its edges by some sub-pixel amount to further increase conservative pixel coverage. Implementations can allow the application to specify an extra overestimation beyond the base overestimation the implementation already does. It also allows implementations to either cull degenerate primitives or rasterize them.

When underestimation is enabled, fragments are only generated if the rectangular pixel area is fully covered by the generating primitive. If supported by the implementation, when a pixel rectangle is fully covered the fragment shader input variable builtin called FullyCoveredEXT is set to true. The shader variable works in either overestimation or underestimation mode.

Implementations can process degenerate triangles and lines by either discarding them or generating conservative fragments for them. Degenerate triangles are those that end up with zero area after the rasterizer quantizes them to the fixed-point pixel grid. Degenerate lines are those with zero length after quantization.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_CONSERVATIVE_RASTERIZATION_PROPERTIES_EXT`

  - `VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_CONSERVATIVE_STATE_CREATE_INFO_EXT`

#### New Enums

- VkPipelineRasterizationConservativeStateCreateFlagsEXT

- VkConservativeRasterizationModeEXT

#### New Structures

- VkPhysicalDeviceConservativeRasterizationPropertiesEXT

- VkPipelineRasterizationConservativeStateCreateInfoEXT

#### New Functions

None.

#### Issues

None.

#### Version History

- Revision 1, 2017-08-28 (Piers Daniell)

  - Internal revisions

#### VK_EXT_debug_utils

Name String

  `VK_EXT_debug_utils`

Extension Type

  Instance extension

Registered Extension Number

  129

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Mark Young marky-lunarg

Last Modified Date

  2017-09-14

Revision

  1

IP Status

  No known IP claims.

Dependencies

  - This extension is written against version 1.0 of the Vulkan API.

  - Requires VkObjectType

Contributors

  - Mark Young, LunarG

  - Baldur Karlsson

  - Ian Elliott, Google

  - Courtney Goeltzenleuchter, Google

  - Karl Schultz, LunarG

  - Mark Lobodzinski, LunarG

  - Mike Schuchardt, LunarG

  - Jaakko Konttinen, AMD

  - Dan Ginsburg, Valve Software

  - Rolando Olivares, Epic Games

  - Dan Baker, Oxide Games

  - Kyle Spagnoli, NVIDIA

  - Jon Ashburn, LunarG

Due to the nature of the Vulkan interface, there is very little error information available to the developer and application. By using the `VK_EXT_debug_utils` extension, developers can obtain more information. When combined with validation layers, even more detailed feedback on the application’s use of Vulkan will be provided.

This extension provides the following capabilities:

- The ability to create a debug messenger which will pass along debug messages to an application supplied callback.

- The ability to identify specific Vulkan objects using a name or tag to improve tracking.

- The ability to identify specific sections within a `VkQueue` or `VkCommandBuffer` using labels to aid organization and offline analysis in external tools.

The main difference between this extension and `VK_EXT_debug_report` and `VK_EXT_debug_marker` is that those extensions use VkDebugReportObjectTypeEXT to identify objects. This extension uses the core VkObjectType in place of VkDebugReportObjectTypeEXT. The primary reason for this move is that no future object type handle enumeration values will be added to VkDebugReportObjectTypeEXT since the creation of VkObjectType.

In addition, this extension combines the functionality of both `VK_EXT_debug_report` and `VK_EXT_debug_marker` by allowing object name and debug markers (now called labels) to be returned to the application’s callback function. This should assist in clarifying the details of a debug message including: what objects are involved and potentially which location within a VkQueue or VkCommandBuffer the message occurred.

#### New Object Types

- VkDebugUtilsMessengerEXT

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_DEBUG_UTILS_OBJECT_NAME_INFO_EXT`

  - `VK_STRUCTURE_TYPE_DEBUG_UTILS_OBJECT_TAG_INFO_EXT`

  - `VK_STRUCTURE_TYPE_DEBUG_UTILS_LABEL_EXT`

  - `VK_STRUCTURE_TYPE_DEBUG_UTILS_MESSENGER_CALLBACK_DATA_EXT`

  - `VK_STRUCTURE_TYPE_DEBUG_UTILS_MESSENGER_CREATE_INFO_EXT`

- Extending VkResult:

  - `VK_ERROR_VALIDATION_FAILED_EXT`

#### New Enums

- VkDebugUtilsMessageSeverityFlagBitsEXT

- VkDebugUtilsMessageTypeFlagBitsEXT

#### New Structures

- VkDebugUtilsObjectNameInfoEXT

- VkDebugUtilsObjectTagInfoEXT

- VkDebugUtilsLabelEXT

- VkDebugUtilsMessengerCallbackDataEXT

- VkDebugUtilsMessengerCreateInfoEXT

#### New Functions

- vkSetDebugUtilsObjectNameEXT

- vkSetDebugUtilsObjectTagEXT

- vkQueueBeginDebugUtilsLabelEXT

- vkQueueEndDebugUtilsLabelEXT

- vkQueueInsertDebugUtilsLabelEXT

- vkCmdBeginDebugUtilsLabelEXT

- vkCmdEndDebugUtilsLabelEXT

- vkCmdInsertDebugUtilsLabelEXT

- vkCreateDebugUtilsMessengerEXT

- vkDestroyDebugUtilsMessengerEXT

- vkSubmitDebugUtilsMessageEXT

#### New Function Pointers

- PFN_vkDebugUtilsMessengerCallbackEXT

#### Examples

Example 1

`VK_EXT_debug_utils` allows an application to register multiple callbacks with any Vulkan component wishing to report debug information. Some callbacks may log the information to a file, others may cause a debug break point or other application defined behavior. An application can register callbacks even when no validation layers are enabled, but they will only be called for loader and, if implemented, driver events.

To capture events that occur while creating or destroying an instance an application can link a VkDebugUtilsMessengerCreateInfoEXT structure to the `pNext` element of the VkInstanceCreateInfo structure given to vkCreateInstance. This callback is only valid for the duration of the vkCreateInstance and the vkDestroyInstance call. Use vkCreateDebugUtilsMessengerEXT to create persistent callback objects.

Example uses: Create three callback objects. One will log errors and warnings to the debug console using Windows `OutputDebugString`. The second will cause the debugger to break at that callback when an error happens and the third will log warnings to stdout.

        extern VkInstance instance;
        VkResult res;
        VkDebugUtilsMessengerEXT cb1, cb2, cb3;

        // Must call extension functions through a function pointer:
        PFN_vkCreateDebugUtilsMessengerEXT pfnCreateDebugUtilsMessengerEXT = (PFN_vkCreateDebugUtilsMessengerEXT)vkGetDeviceProcAddr(device, "vkCreateDebugUtilsMessengerEXT");
        PFN_vkDestroyDebugUtilsMessengerEXT pfnDestroyDebugUtilsMessengerEXT = (PFN_vkDestroyDebugUtilsMessengerEXT)vkGetDeviceProcAddr(device, "vkDestroyDebugUtilsMessengerEXT");

        VkDebugUtilsMessengeCreateInfoEXT callback1 = {
                VK_STRUCTURE_TYPE_DEBUG_UTILS_MESSENGER_CREATE_INFO_EXT,  // sType
                NULL,                                                     // pNext
                0,                                                        // flags
                VK_DEBUG_UTILS_MESSAGE_SEVERITY_ERROR_BIT_EXT |           // messageSeverity
                VK_DEBUG_UTILS_MESSAGE_SEVERITY_WARNING_BIT_EXT,
                VK_DEBUG_UTILS_MESSAGE_TYPE_GENERAL_BIT_EXT |             // messageType
                VK_DEBUG_UTILS_MESSAGE_TYPE_VALIDATION_BIT_EXT,
                myOutputDebugString,                                      // pfnUserCallback
                NULL                                                      // pUserData
        };
        res = pfnCreateDebugUtilsMessengerEXT(instance, &callback1, NULL, &cb1);
        if (res != VK_SUCCESS) {
           // Do error handling for VK_ERROR_OUT_OF_MEMORY
        }

        callback1.messageSeverity = VK_DEBUG_UTILS_MESSAGE_SEVERITY_ERROR_BIT_EXT;
        callback1.pfnCallback = myDebugBreak;
        callback1.pUserData = NULL;
        res = pfnCreateDebugUtilsMessengerEXT(instance, &callback1, NULL, &cb2);
        if (res != VK_SUCCESS) {
           // Do error handling for VK_ERROR_OUT_OF_MEMORY
        }

        VkDebugUtilsMessengerCreateInfoEXT callback3 = {
                VK_STRUCTURE_TYPE_DEBUG_UTILS_MESSENGER_CREATE_INFO_EXT,  // sType
                NULL,                                                     // pNext
                0,                                                        // flags
                VK_DEBUG_UTILS_MESSAGE_SEVERITY_WARNING_BIT_EXT,          // messageSeverity
                VK_DEBUG_UTILS_MESSAGE_TYPE_GENERAL_BIT_EXT |             // messageType
                VK_DEBUG_UTILS_MESSAGE_TYPE_VALIDATION_BIT_EXT,
                mystdOutLogger,                                           // pfnUserCallback
                NULL                                                      // pUserData
        };
        res = pfnCreateDebugUtilsMessengerEXT(instance, &callback3, NULL, &cb3);
        if (res != VK_SUCCESS) {
           // Do error handling for VK_ERROR_OUT_OF_MEMORY
        }

        ...

        // Remove callbacks when cleaning up
        pfnDestroyDebugUtilsMessengerEXT(instance, cb1, NULL);
        pfnDestroyDebugUtilsMessengerEXT(instance, cb2, NULL);
        pfnDestroyDebugUtilsMessengerEXT(instance, cb3, NULL);

Example 2

Associate a name with an image, for easier debugging in external tools or with validation layers that can print a friendly name when referring to objects in error messages.

        extern VkDevice device;
        extern VkImage image;

        // Must call extension functions through a function pointer:
        PFN_vkSetDebugUtilsObjectNameEXT pfnSetDebugUtilsObjectNameEXT = (PFN_vkSetDebugUtilsObjectNameEXT)vkGetDeviceProcAddr(device, "vkSetDebugUtilsObjectNameEXT");

        // Set a name on the image
        const VkDebugUtilsObjectNameInfoEXT imageNameInfo =
        {
            VK_STRUCTURE_TYPE_DEBUG_UTILS_OBJECT_NAME_INFO_EXT, // sType
            NULL,                                               // pNext
            VK_OBJECT_TYPE_IMAGE,                               // objectType
            (uint64_t)image,                                    // object
            "Brick Diffuse Texture",                            // pObjectName
        };

        pfnSetDebugUtilsObjectNameEXT(device, &imageNameInfo);

        // A subsequent error might print:
        //   Image 'Brick Diffuse Texture' (0xc0dec0dedeadbeef) is used in a
        //   command buffer with no memory bound to it.

Example 3

Annotating regions of a workload with naming information so that offline analysis tools can display a more usable visualization of the commands submitted.

        extern VkDevice device;
        extern VkCommandBuffer commandBuffer;

        // Must call extension functions through a function pointer:
        PFN_vkQueueBeginDebugUtilsLabelEXT pfnQueueBeginDebugUtilsLabelEXT = (PFN_vkQueueBeginDebugUtilsLabelEXT)vkGetDeviceProcAddr(device, "vkQueueBeginDebugUtilsLabelEXT");
        PFN_vkQueueEndDebugUtilsLabelEXT pfnQueueEndDebugUtilsLabelEXT = (PFN_vkQueueEndDebugUtilsLabelEXT)vkGetDeviceProcAddr(device, "vkQueueEndDebugUtilsLabelEXT");
        PFN_vkCmdBeginDebugUtilsLabelEXT pfnCmdBeginDebugUtilsLabelEXT = (PFN_vkCmdBeginDebugUtilsLabelEXT)vkGetDeviceProcAddr(device, "vkCmdBeginDebugUtilsLabelEXT");
        PFN_vkCmdEndDebugUtilsLabelEXT pfnCmdEndDebugUtilsLabelEXT = (PFN_vkCmdEndDebugUtilsLabelEXT)vkGetDeviceProcAddr(device, "vkCmdEndDebugUtilsLabelEXT");
        PFN_vkCmdInsertDebugUtilsLabelEXT pfnCmdInsertDebugUtilsLabelEXT = (PFN_vkCmdInsertDebugUtilsLabelEXT)vkGetDeviceProcAddr(device, "vkCmdInsertDebugUtilsLabelEXT");

        // Describe the area being rendered
        const VkDebugUtilsLabelEXT houseLabel =
        {
            VK_STRUCTURE_TYPE_DEBUG_UTILS_LABEL_EXT, // sType
            NULL,                                    // pNext
            "Brick House",                           // pLabelName
            { 1.0f, 0.0f, 0.0f, 1.0f },              // color
        };

        // Start an annotated group of calls under the 'Brick House' name
        pfnCmdBeginDebugUtilsLabelEXT(commandBuffer, &houseLabel);
        {
            // A mutable structure for each part being rendered
            VkDebugUtilsLabelEXT housePartLabel =
            {
                VK_STRUCTURE_TYPE_DEBUG_UTILS_LABEL_EXT, // sType
                NULL,                                    // pNext
                NULL,                                    // pLabelName
                { 0.0f, 0.0f, 0.0f, 0.0f },              // color
            };

            // Set the name and insert the marker
            housePartLabel.pLabelName = "Walls";
            pfnCmdInsertDebugUtilsLabelEXT(commandBuffer, &housePartLabel);

            // Insert the drawcall for the walls
            vkCmdDrawIndexed(commandBuffer, 1000, 1, 0, 0, 0);

            // Insert a recursive region for two sets of windows
            housePartLabel.pLabelName = "Windows";
            pfnCmdBeginDebugUtilsLabelEXT(commandBuffer, &housePartLabel);
            {
                vkCmdDrawIndexed(commandBuffer, 75, 6, 1000, 0, 0);
                vkCmdDrawIndexed(commandBuffer, 100, 2, 1450, 0, 0);
            }
            pfnCmdEndDebugUtilsLabelEXT(commandBuffer);

            housePartLabel.pLabelName = "Front Door";
            pfnCmdInsertDebugUtilsLabelEXT(commandBuffer, &housePartLabel);

            vkCmdDrawIndexed(commandBuffer, 350, 1, 1650, 0, 0);

            housePartLabel.pLabelName = "Roof";
            pfnCmdInsertDebugUtilsLabelEXT(commandBuffer, &housePartLabel);

            vkCmdDrawIndexed(commandBuffer, 500, 1, 2000, 0, 0);
        }
        // End the house annotation started above
        pfnCmdEndDebugUtilsLabelEXT(commandBuffer);

        // Do other work

        vkEndCommandBuffer(commandBuffer);

        // Describe the queue being used
        const VkDebugUtilsLabelEXT queueLabel =
        {
            VK_STRUCTURE_TYPE_DEBUG_UTILS_LABEL_EXT, // sType
            NULL,                                    // pNext
            "Main Render Work",                      // pLabelName
            { 0.0f, 1.0f, 0.0f, 1.0f },              // color
        };

        // Identify the queue label region
        pfnQueueBeginDebugUtilsLabelEXT(queue, &queueLabel);

        // Submit the work for the main render thread
        const VkCommandBuffer cmd_bufs[] = {commandBuffer};
        VkSubmitInfo submit_info = {.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO,
                                    .pNext = NULL,
                                    .waitSemaphoreCount = 0,
                                    .pWaitSemaphores = NULL,
                                    .pWaitDstStageMask = NULL,
                                    .commandBufferCount = 1,
                                    .pCommandBuffers = cmd_bufs,
                                    .signalSemaphoreCount = 0,
                                    .pSignalSemaphores = NULL};
        vkQueueSubmit(queue, 1, &submit_info, fence);

        // End the queue label region
        pfnQueueEndDebugUtilsLabelEXT(queue);

#### Issues

1) Should we just name this extension `VK_EXT_debug_report2`

RESOLVED: No. There is enough additional changes to the structures to break backwards compatibility. So, a new name was decided that would not indicate any interaction with the previous extension.

2) Will validation layers immediately support all the new features.

RESOLVED: Not immediately. As one can imagine, there is a lot of work involved with converting the validation layer logging over to the new functionality. Basic logging, as seen in the origin `VK_EXT_debug_report` extension will be made available immediately. However, adding the labels and object names will take time. Since the priority for Khronos at this time is to continue focusing on Valid Usage statements, it may take a while before the new functionality is fully exposed.

3) If the validation layers won’t expose the new functionality immediately, then what’s the point of this extension?

RESOLVED: We needed a replacement for `VK_EXT_debug_report` because the VkDebugReportObjectTypeEXT enumeration will no longer be updated and any new objects will need to be debugged using the new functionality provided by this extension.

4) Should this extension be split into two separate parts (1 extension that is an instance extension providing the callback functionality, and another device extension providing the general debug marker and annotation functionality)?

RESOLVED: No, the functionality for this extension is too closely related. If we did split up the extension, where would the structures and enums live, and how would you define that the device behavior in the instance extension is really only valid if the device extension is enabled, and the functionality is passed in. It’s cleaner to just define this all as an instance extension, plus it allows the application to enable all debug functionality provided with one enable string during vkCreateInstance.

#### Version History

- Revision 1, 2017-09-14 (Mark Young and all listed Contributors)

  - Initial draft, based on `VK_EXT_debug_report` and `VK_EXT_debug_marker` in addition to previous feedback supplied from various companies including Valve, Epic, and Oxide games.

#### VK_EXT_depth_clip_enable

Name String

  `VK_EXT_depth_clip_enable`

Extension Type

  Device extension

Registered Extension Number

  103

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Piers Daniell pdaniell-nv

Last Modified Data

  2018-12-20

Contributors

  - Daniel Rakos, AMD

  - Henri Verbeet, CodeWeavers

  - Jeff Bolz, NVIDIA

  - Philip Rebohle, DXVK

  - Tobias Hector, AMD

This extension allows the depth clipping operation, that is normally implicitly controlled by VkPipelineRasterizationStateCreateInfo::`depthClampEnable`, to instead be controlled explicitly by VkPipelineRasterizationDepthClipStateCreateInfoEXT::`depthClipEnable`.

This is useful for translating DX content which assumes depth clamping is always enabled, but depth clip can be controlled by the DepthClipEnable rasterization state (D3D12_RASTERIZER_DESC).

#### New Object Types

None

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DEPTH_CLIP_ENABLE_FEATURES_EXT`

  - `VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_DEPTH_CLIP_STATE_CREATE_INFO_EXT`

#### New Enums

- VkPipelineRasterizationDepthClipStateCreateFlagsEXT

#### New Structures

- VkPhysicalDeviceDepthClipEnableFeaturesEXT

- VkPipelineRasterizationDepthClipStateCreateInfoEXT

#### New Functions

None

#### Issues

None

#### Version History

- Revision 1, 2018-12-20 (Piers Daniell)

  - Internal revisions

#### VK_EXT_depth_range_unrestricted

Name String

  `VK_EXT_depth_range_unrestricted`

Extension Type

  Device extension

Registered Extension Number

  14

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Piers Daniell pdaniell-nv

Last Modified Date

  2017-06-22

Contributors

  - Daniel Koch, NVIDIA

  - Jeff Bolz, NVIDIA

This extension removes the VkViewport `minDepth` and `maxDepth` restrictions that the values must be between `0.0` and `1.0`, inclusive. It also removes the same restriction on VkPipelineDepthStencilStateCreateInfo `minDepthBounds` and `maxDepthBounds`. Finally it removes the restriction on the `depth` value in VkClearDepthStencilValue.

#### New Object Types

None.

#### New Enum Constants

None.

#### New Enums

None.

#### New Structures

None.

#### New Functions

None.

#### Issues

1) How do VkViewport `minDepth` and `maxDepth` values outside of the `0.0` to `1.0` range interact with Primitive Clipping?

RESOLVED: The behavior described in Primitive Clipping still applies. If depth clamping is disabled the depth values are still clipped to 0 ≤ zc ≤ wc before the viewport transform. If depth clamping is enabled the above equation is ignored and the depth values are instead clamped to the VkViewport `minDepth` and `maxDepth` values, which in the case of this extension can be outside of the `0.0` to `1.0` range.

2) What happens if a resulting depth fragment is outside of the `0.0` to `1.0` range and the depth buffer is fixed-point rather than floating-point?

RESOLVED: The supported range of a fixed-point depth buffer is `0.0` to `1.0` and depth fragments are clamped to this range.

#### Version History

- Revision 1, 2017-06-22 (Piers Daniell)

  - Internal revisions

#### VK_EXT_direct_mode_display

Name String

  `VK_EXT_direct_mode_display`

Extension Type

  Instance extension

Registered Extension Number

  89

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_display`

Contact

  - James Jones cubanismo

Last Modified Date

  2016-12-13

IP Status

  No known IP claims.

Contributors

  - Pierre Boudier, NVIDIA

  - James Jones, NVIDIA

  - Damien Leone, NVIDIA

  - Pierre-Loup Griffais, Valve

  - Liam Middlebrook, NVIDIA

This is extension, along with related platform exentions, allows applications to take exclusive control of displays associated with a native windowing system. This is especially useful for virtual reality applications that wish to hide HMDs (head mounted displays) from the native platform’s display management system, desktop, and/or other applications.

#### New Enum Constants

None.

#### New Enums

None.

#### New Structures

None.

#### New Functions

- vkReleaseDisplayEXT

#### Issues

1) Should this extension and its related platform-specific extensions leverage `VK_KHR_display`, or provide separate equivalent interfaces.

RESOLVED: Use `VK_KHR_display` concepts and objects. `VK_KHR_display` can be used to enumerate all displays on the system, including those attached to/in use by a window system or native platform, but `VK_KHR_display_swapchain` will fail to create a swapchain on in-use displays. This extension and its platform-specific children will allow applications to grab in-use displays away from window systems and/or native platforms, allowing them to be used with `VK_KHR_display_swapchain`.

2) Are separate calls needed to acquire displays and enable direct mode?

RESOLVED: No, these operations happen in one combined command. Acquiring a display puts it into direct mode.

#### Version History

- Revision 1, 2016-12-13 (James Jones)

  - Initial draft

#### VK_EXT_discard_rectangles

Name String

  `VK_EXT_discard_rectangles`

Extension Type

  Device extension

Registered Extension Number

  100

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Piers Daniell pdaniell-nv

Last Modified Date

  2016-12-22

Interactions and External Dependencies

  - Interacts with `VK_KHR_device_group`

  - Interacts with Vulkan 1.1

Contributors

  - Daniel Koch, NVIDIA

  - Jeff Bolz, NVIDIA

This extension provides additional orthogonally aligned “discard rectangles” specified in framebuffer-space coordinates that restrict rasterization of all points, lines and triangles.

From zero to an implementation-dependent limit (specified by `maxDiscardRectangles`) number of discard rectangles can be operational at once. When one or more discard rectangles are active, rasterized fragments can either survive if the fragment is within any of the operational discard rectangles (`VK_DISCARD_RECTANGLE_MODE_INCLUSIVE_EXT` mode) or be rejected if the fragment is within any of the operational discard rectangles (`VK_DISCARD_RECTANGLE_MODE_EXCLUSIVE_EXT` mode).

These discard rectangles operate orthogonally to the existing scissor test functionality. The discard rectangles can be different for each physical device in a device group by specifying the device mask and setting discard rectangle dynamic state.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DISCARD_RECTANGLE_PROPERTIES_EXT`

  - `VK_STRUCTURE_TYPE_PIPELINE_DISCARD_RECTANGLE_STATE_CREATE_INFO_EXT`

- Extending VkDynamicState

  - `VK_DYNAMIC_STATE_DISCARD_RECTANGLE_EXT`

#### New Enums

- VkPipelineDiscardRectangleStateCreateFlagsEXT

- VkDiscardRectangleModeEXT

#### New Structures

- VkPhysicalDeviceDiscardRectanglePropertiesEXT

- VkPipelineDiscardRectangleStateCreateInfoEXT

#### New Functions

- vkCmdSetDiscardRectangleEXT

#### Issues

None.

#### Version History

- Revision 1, 2016-12-22 (Piers Daniell)

  - Internal revisions

#### VK_EXT_display_control

Name String

  `VK_EXT_display_control`

Extension Type

  Device extension

Registered Extension Number

  92

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_EXT_display_surface_counter`

  - Requires `VK_KHR_swapchain`

Contact

  - James Jones cubanismo

Last Modified Date

  2016-12-13

IP Status

  No known IP claims.

Contributors

  - Pierre Boudier, NVIDIA

  - James Jones, NVIDIA

  - Damien Leone, NVIDIA

  - Pierre-Loup Griffais, Valve

  - Daniel Vetter, Intel

This extension defines a set of utility functions for use with the `VK_KHR_display` and `VK_KHR_display_swapchain` extensions.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_DISPLAY_POWER_INFO_EXT`

  - `VK_STRUCTURE_TYPE_DEVICE_EVENT_INFO_EXT`

  - `VK_STRUCTURE_TYPE_DISPLAY_EVENT_INFO_EXT`

  - `VK_STRUCTURE_TYPE_SWAPCHAIN_COUNTER_CREATE_INFO_EXT`

#### New Enums

- VkDisplayPowerStateEXT

- VkDeviceEventTypeEXT

- VkDisplayEventTypeEXT

#### New Structures

- VkDisplayPowerInfoEXT

- VkDeviceEventInfoEXT

- VkDisplayEventInfoEXT

- VkSwapchainCounterCreateInfoEXT

#### New Functions

- vkDisplayPowerControlEXT

- vkRegisterDeviceEventEXT

- vkRegisterDisplayEventEXT

- vkGetSwapchainCounterEXT

#### Issues

1) Should this extension add an explicit “WaitForVsync” API or a fence signaled at vsync that the application can wait on?

RESOLVED: A fence. A separate API could later be provided that allows exporting the fence to a native object that could be inserted into standard run loops on POSIX and Windows systems.

2) Should callbacks be added for a vsync event, or in general to monitor events in Vulkan?

RESOLVED: No, fences should be used. Some events are generated by interrupts which are managed in the kernel. In order to use a callback provided by the application, drivers would need to have the userspace driver spawn threads that would wait on the kernel event, and hence the callbacks could be difficult for the application to synchronize with its other work given they would arrive on a foreign thread.

3) Should vblank or scanline events be exposed?

RESOLVED: Vblank events. Scanline events could be added by a separate extension, but the latency of processing an interrupt and waking up a userspace event is high enough that the accuracy of a scanline event would be rather low. Further, per-scanline interrupts are not supported by all hardware.

#### Version History

- Revision 1, 2016-12-13 (James Jones)

  - Initial draft

#### VK_EXT_display_surface_counter

Name String

  `VK_EXT_display_surface_counter`

Extension Type

  Instance extension

Registered Extension Number

  91

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_display`

Contact

  - James Jones cubanismo

Last Modified Date

  2016-12-13

IP Status

  No known IP claims.

Contributors

  - Pierre Boudier, NVIDIA

  - James Jones, NVIDIA

  - Damien Leone, NVIDIA

  - Pierre-Loup Griffais, Valve

  - Daniel Vetter, Intel

This is extension defines a vertical blanking period counter associated with display surfaces. It provides a mechanism to query support for such a counter from a VkSurfaceKHR object.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_SURFACE_CAPABILITIES_2_EXT`

#### New Enums

- VkSurfaceCounterFlagsEXT

- VkSurfaceCounterFlagBitsEXT

#### New Structures

- VkSurfaceCapabilities2EXT

#### New Functions

- vkGetPhysicalDeviceSurfaceCapabilities2EXT

#### Issues

None.

#### Version History

- Revision 1, 2016-12-13 (James Jones)

  - Initial draft

#### VK_EXT_external_memory_dma_buf

Name String

  `VK_EXT_external_memory_dma_buf`

Extension Type

  Device extension

Registered Extension Number

  126

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_external_memory_fd`

Contact

  - Chad Versace chadversary

Last Modified Date

  2017-10-10

IP Status

  No known IP claims.

Contributors

  - Chad Versace, Google

  - James Jones, NVIDIA

  - Jason Ekstrand, Intel

A `dma_buf` is a type of file descriptor, defined by the Linux kernel, that allows sharing memory across kernel device drivers and across processes. This extension enables applications to import a `dma_buf` as VkDeviceMemory, to export VkDeviceMemory as a `dma_buf`, and to create VkBuffer objects that can be bound to that memory.

#### New Enum Constants

- Extending VkExternalMemoryHandleTypeFlagBitsKHR:

  - `VK_EXTERNAL_MEMORY_HANDLE_TYPE_DMA_BUF_BIT_EXT`

#### Issues

1) How does the application, when creating a VkImage that it intends to bind to `dma_buf` VkDeviceMemory containing an externally produced image, specify the memory layout (such as row pitch and DRM format modifier) of the VkImage? In other words, how does the application achieve behavior comparable to that provided by `EGL_EXT_image_dma_buf_import` and `EGL_EXT_image_dma_buf_import_modifiers` ?

RESOLVED: Features comparable to those in `EGL_EXT_image_dma_buf_import` and `EGL_EXT_image_dma_buf_import_modifiers` will be provided by an extension layered atop this one.

2) Without the ability to specify the memory layout of external `dma_buf` images, how is this extension useful?

RESOLVED: This extension provides exactly one new feature: the ability to import/export between `dma_buf` and VkDeviceMemory. This feature, together with features provided by `VK_KHR_external_memory_fd`, is sufficient to bind a VkBuffer to `dma_buf`.

#### Version History

- Revision 1, 2017-10-10 (Chad Versace)

  - Squashed internal revisions

#### VK_EXT_external_memory_host

Name String

  `VK_EXT_external_memory_host`

Extension Type

  Device extension

Registered Extension Number

  179

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_external_memory`

Contact

  - Daniel Rakos drakos-amd

Last Modified Date

  2017-11-10

IP Status

  No known IP claims.

Contributors

  - Jaakko Konttinen, AMD

  - David Mao, AMD

  - Daniel Rakos, AMD

  - Tobias Hector, Imagination Technologies

  - Jason Ekstrand, Intel

  - James Jones, NVIDIA

This extension enables an application to import host allocations and host mapped foreign device memory to Vulkan memory objects.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_IMPORT_MEMORY_HOST_POINTER_INFO_EXT`

  - `VK_STRUCTURE_TYPE_MEMORY_HOST_POINTER_PROPERTIES_EXT`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_MEMORY_HOST_PROPERTIES_EXT`

- Extending VkExternalMemoryHandleTypeFlagBitsKHR:

  - `VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_ALLOCATION_BIT_EXT`

  - `VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_MAPPED_FOREIGN_MEMORY_BIT_EXT`

#### New Enums

None.

#### New Structs

- VkImportMemoryHostPointerInfoEXT

- VkMemoryHostPointerPropertiesEXT

- VkPhysicalDeviceExternalMemoryHostPropertiesEXT

#### New Functions

- vkGetMemoryHostPointerPropertiesEXT

#### Issues

1) What memory type has to be used to import host pointers?

RESOLVED: Depends on the implementation. Applications have to use the new vkGetMemoryHostPointerPropertiesEXT command to query the supported memory types for a particular host pointer. The reported memory types may include memory types that come from a memory heap that is otherwise not usable for regular memory object allocation and thus such a heap’s size may be zero.

2) Can the application still access the contents of the host allocation after importing?

RESOLVED: Yes. However, usual synchronization requirements apply.

3) Can the application free the host allocation?

RESOLVED: No, it violates valid usage conditions. Using the memory object imported from a host allocation that’s already freed thus results in undefined behavior.

4) Is vkMapMemory expected to return the same host address which was specified when importing it to the memory object?

RESOLVED: No. Implementations are allowed to return the same address but it’s not required. Some implementations might return a different virtual mapping of the allocation, although the same physical pages will be used.

5) Is there any limitation on the alignment of the host pointer and/or size?

RESOLVED: Yes. Both the address and the size have to be an integer multiple of `minImportedHostPointerAlignment`. In addition, some platforms and foreign devices may have additional restrictions.

6) Can the same host allocation be imported multiple times into a given physical device?

RESOLVED: No, at least not guaranteed by this extension. Some platforms do not allow locking the same physical pages for device access multiple times, so attempting to do it may result in undefined behavior.

7) Does this extension support exporting the new handle type?

RESOLVED: No.

8) Should we include the possibility to import host mapped foreign device memory using this API?

RESOLVED: Yes, through a separate handle type. Implementations are still allowed to support only one of the handle types introduced by this extension by not returning import support for a particular handle type as returned in VkExternalMemoryPropertiesKHR.

#### Version History

- Revision 1, 2017-11-10 (Daniel Rakos)

  - Internal revisions

#### VK_EXT_filter_cubic

Name String

  `VK_EXT_filter_cubic`

Extension Type

  Device extension

Registered Extension Number

  171

Revision

  3

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_IMG_filter_cubic`

Contact

  - Bill Licea-Kane wwlk

Last Modified Date

  2019-12-13

Contributors

  - Bill Licea-Kane, Qualcomm Technologies, Inc.

  - Andrew Garrard, Samsung

  - Daniel Koch, NVIDIA

  - Donald Scorgie, Imagination Technologies

  - Graeme Leese, Broadcom

  - Jan-Herald Fredericksen, ARM

  - Jeff Leger, Qualcomm Technologies, Inc.

  - Tobias Hector, AMD

  - Tom Olson, ARM

  - Stuart Smith, Imagination Technologies

`VK_EXT_filter_cubic` extends `VK_IMG_filter_cubic`.

It documents cubic filtering of other image view types. It adds new structures that can be added to the `pNext` chain of VkPhysicalDeviceImageFormatInfo2 and VkImageFormatProperties2 that can be used to determine which image types and which image view types support cubic filtering.

#### New Structures

- VkPhysicalDeviceImageViewImageFormatInfoEXT

- VkFilterCubicImageViewImageFormatPropertiesEXT

#### Version History

- Revision 3, 2019-12-13 (wwlk)

  - Delete requirement to cubic filter the formats USCALED_PACKED32, SSCALED_PACKED32, UINT_PACK32, and SINT_PACK32 (cut/paste error)

- Revision 2, 2019-06-05 (wwlk)

  - Clarify 1D optional

- Revision 1, 2019-01-24 (wwlk)

  - Initial version

#### VK_EXT_fragment_density_map

Name String

  `VK_EXT_fragment_density_map`

Extension Type

  Device extension

Registered Extension Number

  219

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Matthew Netsch mnetsch

Last Modified Date

  2018-09-25

Interactions and External Dependencies

  - This extension requires the `SPV_EXT_fragment_invocation_density` SPIR-V extension.

Contributors

  - Matthew Netsch, Qualcomm Technologies, Inc.

  - Robert VanReenen, Qualcomm Technologies, Inc.

  - Jonathan Wicks, Qualcomm Technologies, Inc.

  - Tate Hornbeck, Qualcomm Technologies, Inc.

  - Sam Holmes, Qualcomm Technologies, Inc.

  - Jeff Leger, Qualcomm Technologies, Inc.

  - Jan-Harald Fredriksen, ARM

  - Jeff Bolz, NVIDIA

  - Pat Brown, NVIDIA

  - Daniel Rakos, AMD

  - Piers Daniell, NVIDIA

This extension allows an application to specify areas of the render target where the fragment shader may be invoked fewer times. These fragments are broadcasted out to multiple pixels to cover the render target.

The primary use of this extension is to reduce workloads in areas where lower quality may not be perceived such as the distorted edges of a lens or the periphery of a user’s gaze.

#### New Object Types

None.

#### New Enum Constants

- Extending VkAccessFlagBits:

  - `VK_ACCESS_FRAGMENT_DENSITY_MAP_READ_BIT_EXT`

- Extending VkFormatFeatureFlagBits:

  - `VK_FORMAT_FEATURE_FRAGMENT_DENSITY_MAP_BIT_EXT`

- Extending VkImageCreateFlagBits:

  - `VK_IMAGE_CREATE_SUBSAMPLED_BIT_EXT`

- Extending VkImageLayout:

  - `VK_IMAGE_LAYOUT_FRAGMENT_DENSITY_MAP_OPTIMAL_EXT`

- Extending VkImageUsageFlagBits:

  - `VK_IMAGE_USAGE_FRAGMENT_DENSITY_MAP_BIT_EXT`

- Extending VkImageViewCreateFlagBits:

  - `VK_IMAGE_VIEW_CREATE_FRAGMENT_DENSITY_MAP_DYNAMIC_BIT_EXT`

- Extending VkPipelineStageFlagBits:

  - `VK_PIPELINE_STAGE_FRAGMENT_DENSITY_PROCESS_BIT_EXT`

- Extending VkSamplerCreateFlagBits:

  - `VK_SAMPLER_CREATE_SUBSAMPLED_BIT_EXT`

  - `VK_SAMPLER_CREATE_SUBSAMPLED_COARSE_RECONSTRUCTION_BIT_EXT`

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FRAGMENT_DENSITY_MAP_FEATURES_EXT`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FRAGMENT_DENSITY_MAP_PROPERTIES_EXT`

  - `VK_STRUCTURE_TYPE_RENDER_PASS_FRAGMENT_DENSITY_MAP_CREATE_INFO_EXT`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceFragmentDensityMapFeaturesEXT

- VkPhysicalDeviceFragmentDensityMapPropertiesEXT

- VkRenderPassFragmentDensityMapCreateInfoEXT

#### New Functions

None.

#### New or Modified Built-In Variables

- `FragInvocationCountEXT`

- `FragSizeEXT`

#### New Variable Decorations

None.

#### New SPIR-V Capabilities

- FragmentDensityEXT

#### Version History

- Revision 1, 2018-09-25 (Matthew Netsch)

  - Initial version

#### VK_EXT_fragment_shader_interlock

Name String

  `VK_EXT_fragment_shader_interlock`

Extension Type

  Device extension

Registered Extension Number

  252

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Piers Daniell pdaniell-nv

Last Modified Data

  2019-05-02

Interactions and External Dependencies

  - This extension requires the `SPV_EXT_fragment_shader_interlock` SPIR-V extension.

  - This extension requires the `GL_ARB_fragment_shader_interlock`, extensions for GLSL source languages.

Contributors

  - Daniel Koch, NVIDIA

  - Graeme Leese, Broadcom

  - Jan-Harald Fredriksen, Arm

  - Jason Ekstrand, Intel

  - Jeff Bolz, NVIDIA

  - Ruihao Zhang, Qualcomm

  - Slawomir Grajewski, Intel

  - Spencer Fricke, Samsung

This extension adds support for the `FragmentShaderPixelInterlockEXT`, `FragmentShaderSampleInterlockEXT`, and `FragmentShaderShadingRateInterlockEXT` capabilities from the `SPV_EXT_fragment_shader_interlock` extension to Vulkan.

Enabling these capabilities provides a critical section for fragment shaders to avoid overlapping pixels being processed at the same time, and certain guarantees about the ordering of fragment shader invocations of fragments of overlapping pixels.

This extension can be useful for algorithms that need to access per-pixel data structures via shader loads and stores. Algorithms using this extension can access per-pixel data structures in critical sections without other invocations accessing the same per-pixel data. Additionally, the ordering guarantees are useful for cases where the API ordering of fragments is meaningful. For example, applications may be able to execute programmable blending operations in the fragment shader, where the destination buffer is read via image loads and the final value is written via image stores.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FRAGMENT_SHADER_INTERLOCK_FEATURES_EXT`

#### New Enums

None.

#### New Structures

- Extending VkPhysicalDeviceFeatures2:

  - VkPhysicalDeviceFragmentShaderInterlockFeaturesEXT

#### New Functions

None.

#### New SPIR-V Capabilities

- FragmentShaderInterlockEXT

- FragmentShaderPixelInterlockEXT

- FragmentShaderShadingRateInterlockEXT

#### Issues

None.

#### Version History

- Revision 1, 2019-05-24 (Piers Daniell)

  - Internal revisions

#### VK_EXT_full_screen_exclusive

Name String

  `VK_EXT_full_screen_exclusive`

Extension Type

  Device extension

Registered Extension Number

  256

Revision

  4

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

  - Requires `VK_KHR_surface`

  - Requires `VK_KHR_get_surface_capabilities2`

  - Requires `VK_KHR_swapchain`

Contact

  - James Jones cubanismo

Last Modified Date

  2019-03-12

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Interacts with Vulkan 1.1

  - Interacts with `VK_KHR_device_group`

  - Interacts with `VK_KHR_win32_surface`

Contributors

  - Hans-Kristian Arntzen, ARM

  - Slawomir Grajewski, Intel

  - Tobias Hector, AMD

  - James Jones, NVIDIA

  - Daniel Rakos, AMD

  - Jeff Juliano, NVIDIA

  - Joshua Schnarr, NVIDIA

  - Aaron Hagan, AMD

This extension allows applications to set the policy for swapchain creation and presentation mechanisms relating to full-screen access. Implementations may be able to acquire exclusive access to a particular display for an application window that covers the whole screen. This can increase performance on some systems by bypassing composition, however it can also result in disruptive or expensive transitions in the underlying windowing system when a change occurs.

Applications can choose between explicitly disallowing or allowing this behavior, letting the implementation decide, or managing this mode of operation directly using the new vkAcquireFullScreenExclusiveModeEXT and vkReleaseFullScreenExclusiveModeEXT commands.

#### New Enum Constants

- Extending VkResult

  - `VK_ERROR_FULL_SCREEN_EXCLUSIVE_MODE_LOST_EXT`

- Extending VkStructureType

  - `VK_STRUCTURE_TYPE_SURFACE_FULL_SCREEN_EXCLUSIVE_INFO_EXT`

  - `VK_STRUCTURE_TYPE_SURFACE_CAPABILITIES_FULL_SCREEN_EXCLUSIVE_EXT`

  - `VK_STRUCTURE_TYPE_SURFACE_FULL_SCREEN_EXCLUSIVE_WIN32_INFO_EXT`

#### New Enums

- VkFullScreenExclusiveEXT

#### New Structures

- VkSurfaceFullScreenExclusiveInfoEXT

- VkSurfaceCapabilitiesFullScreenExclusiveEXT

- VkSurfaceFullScreenExclusiveWin32InfoEXT

#### New Functions

- vkGetPhysicalDeviceSurfacePresentModes2EXT

- vkGetDeviceGroupSurfacePresentModes2EXT

- vkAcquireFullScreenExclusiveModeEXT

- vkReleaseFullScreenExclusiveModeEXT

#### Issues

1) What should the extension & flag be called?

RESOLVED: VK_EXT_full_screen_exclusive.

Other options considered (prior to the app-controlled mode) were:

- VK_EXT_smooth_fullscreen_transition

- VK_EXT_fullscreen_behavior

- VK_EXT_fullscreen_preference

- VK_EXT_fullscreen_hint

- VK_EXT_fast_fullscreen_transition

- VK_EXT_avoid_fullscreen_exclusive

2) Do we need more than a boolean toggle?

RESOLVED: Yes.

Using an enum with default/allowed/disallowed/app-controlled enables applications to accept driver default behavior, specifically override it in either direction without implying the driver is ever required to use full-screen exclusive mechanisms, or manage this mode explicitly.

3) Should this be a KHR or EXT extension?

RESOLVED: EXT, in order to allow it to be shipped faster.

4) Can the fullscreen hint affect the surface capabilities, and if so, should the hint also be specified as input when querying the surface capabilities?

RESOLVED: Yes on both accounts.

While the hint does not guarantee a particular fullscreen mode will be used when the swapchain is created, it can sometimes imply particular modes will NOT be used. If the driver determines that it will opt-out of using a particular mode based on the policy, and knows it can only support certain capabilities if that mode is used, it would be confusing at best to the application to report those capabilities in such cases. Not allowing implementations to report this state to applications could result in situations where applications are unable to determine why swapchain creation fails when they specify certain hint values, which could result in never- terminating surface creation loops.

5) Should full-screen be one word or two?

RESOLVED: Two words.

"Fullscreen" is not in my dictionary, and web searches did not turn up definitive proof that it is a colloquially accepted compound word. Documentation for the corresponding Windows API mechanisms dithers. The text consistently uses a hyphen, but none-the-less, there is a SetFullscreenState method in the DXGI swapchain object. Given this inconclusive external guidance, it is best to adhere to the Vulkan style guidelines and avoid inventing new compound words.

#### Version History

- Revision 4, 2019-03-12 (Tobias Hector)

  - Added application-controlled mode, and related functions

  - Tidied up appendix

- Revision 3, 2019-01-03 (James Jones)

  - Renamed to VK_EXT_full_screen_exclusive

  - Made related adjustments to the tri-state enumerant names.

- Revision 2, 2018-11-27 (James Jones)

  - Renamed to VK_KHR_fullscreen_behavior

  - Switched from boolean flag to tri-state enum

- Revision 1, 2018-11-06 (James Jones)

  - Internal revision

#### VK_EXT_global_priority

Name String

  `VK_EXT_global_priority`

Extension Type

  Device extension

Registered Extension Number

  175

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Andres Rodriguez lostgoat

Last Modified Date

  2017-10-06

IP Status

  No known IP claims.

Contributors

  - Andres Rodriguez, Valve

  - Pierre-Loup Griffais, Valve

  - Dan Ginsburg, Valve

  - Mitch Singer, AMD

In Vulkan, users can specify device-scope queue priorities. In some cases it may be useful to extend this concept to a system-wide scope. This extension provides a mechanism for caller’s to set their system-wide priority. The default queue priority is `VK_QUEUE_GLOBAL_PRIORITY_MEDIUM_EXT`.

The driver implementation will attempt to skew hardware resource allocation in favour of the higher-priority task. Therefore, higher-priority work may retain similar latency and throughput characteristics even if the system is congested with lower priority work.

The global priority level of a queue shall take precedence over the per-process queue priority (`VkDeviceQueueCreateInfo`::`pQueuePriorities`).

Abuse of this feature may result in starving the rest of the system from hardware resources. Therefore, the driver implementation may deny requests to acquire a priority above the default priority (`VK_QUEUE_GLOBAL_PRIORITY_MEDIUM_EXT`) if the caller does not have sufficient privileges. In this scenario `VK_ERROR_NOT_PERMITTED_EXT` is returned.

The driver implementation may fail the queue allocation request if resources required to complete the operation have been exhausted (either by the same process or a different process). In this scenario `VK_ERROR_INITIALIZATION_FAILED` is returned.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_DEVICE_QUEUE_GLOBAL_PRIORITY_CREATE_INFO_EXT`

- Extending VkResult:

  - `VK_ERROR_NOT_PERMITTED_EXT`

#### New Enums

- VkQueueGlobalPriorityEXT

#### New Structures

- VkDeviceQueueGlobalPriorityCreateInfoEXT

#### New Functions

None.

#### Issues

None.

#### Version History

- Revision 2, 2017-11-03 (Andres Rodriguez)

  - Fixed VkQueueGlobalPriorityEXT missing _EXT suffix

- Revision 1, 2017-10-06 (Andres Rodriguez)

  - First version.

#### VK_EXT_hdr_metadata

Name String

  `VK_EXT_hdr_metadata`

Extension Type

  Device extension

Registered Extension Number

  106

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_swapchain`

Contact

  - Courtney Goeltzenleuchter courtney-g

Last Modified Date

  2018-12-19

IP Status

  No known IP claims.

Contributors

  - Courtney Goeltzenleuchter, Google

This extension defines two new structures and a function to assign SMPTE (the Society of Motion Picture and Television Engineers) 2086 metadata and CTA (Consumer Technology Association) 861.3 metadata to a swapchain. The metadata includes the color primaries, white point, and luminance range of the mastering display, which all together define the color volume that contains all the possible colors the mastering display can produce. The mastering display is the display where creative work is done and creative intent is established. To preserve such creative intent as much as possible and achieve consistent color reproduction on different viewing displays, it is useful for the display pipeline to know the color volume of the original mastering display where content was created or tuned. This avoids performing unnecessary mapping of colors that are not displayable on the original mastering display. The metadata also includes the `maxContentLightLevel` and `maxFrameAverageLightLevel` as defined by CTA 861.3.

While the general purpose of the metadata is to assist in the transformation between different color volumes of different displays and help achieve better color reproduction, it is not in the scope of this extension to define how exactly the metadata should be used in such a process. It is up to the implementation to determine how to make use of the metadata.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_HDR_METADATA_EXT`

#### New Structures

- VkXYColorEXT

- VkHdrMetadataEXT

#### New Functions

- vkSetHdrMetadataEXT

#### Issues

1) Do we need a query function?

PROPOSED: No, Vulkan does not provide queries for state that the application can track on its own.

2) Should we specify default if not specified by the application?

PROPOSED: No, that leaves the default up to the display.

#### Version History

- Revision 1, 2016-12-27 (Courtney Goeltzenleuchter)

  - Initial version

- Revision 2, 2018-12-19 (Courtney Goeltzenleuchter)

  - Correct implicit validity for VkHdrMetadataEXT structure

#### VK_EXT_headless_surface

Name String

  `VK_EXT_headless_surface`

Extension Type

  Instance extension

Registered Extension Number

  257

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_surface`

Contact

  - Lisa Wu chengtianww

Last Modified Date

  2019-03-21

IP Status

  No known IP claims.

Contributors

  - Ray Smith, Arm

The `VK_EXT_headless_surface` extension is an instance extension. It provides a mechanism to create VkSurfaceKHR objects independently of any window system or display device. The presentation operation for a swapchain created from a headless surface is by default a no-op, resulting in no externally-visible result.

Because there is no real presentation target, future extensions can layer on top of the headless surface to introduce arbitrary or customisable sets of restrictions or features. These could include features like saving to a file or restrictions to emulate a particular presentation target.

This functionality is expected to be useful for application and driver development because it allows any platform to expose an arbitrary or customisable set of restrictions and features of a presentation engine. This makes it a useful portable test target for applications targeting a wide range of presentation engines where the actual target presentation engines might be scarce, unavailable or otherwise undesirable or inconvenient to use for general Vulkan application development.

#### New Object Types

None

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_HEADLESS_SURFACE_CREATE_INFO_EXT`

#### New Enums

None

#### New Structures

- VkHeadlessSurfaceCreateInfoEXT

#### New Functions

- vkCreateHeadlessSurfaceEXT

#### Issues

None

#### Version History

- Revision 1, 2019-03-21 (Ray Smith)

  - Initial draft

#### VK_EXT_image_drm_format_modifier

Name String

  `VK_EXT_image_drm_format_modifier`

Extension Type

  Device extension

Registered Extension Number

  159

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_bind_memory2`

  - Requires `VK_KHR_get_physical_device_properties2`

  - Requires `VK_KHR_image_format_list`

  - Requires `VK_KHR_sampler_ycbcr_conversion`

Contact

  - Chad Versace chadversary

Last Modified Date

  2018-08-29

IP Status

  No known IP claims.

Contributors

  - Antoine Labour, Google

  - Bas Nieuwenhuizen, Google

  - Chad Versace, Google

  - James Jones, NVIDIA

  - Jason Ekstrand, Intel

  - Jőrg Wagner, ARM

  - Kristian Høgsberg Kristensen, Google

  - Ray Smith, ARM

#### Overview

##### Summary

This extension provides the ability to use DRM format modifiers with images, enabling Vulkan to better integrate with the Linux ecosystem of graphics, video, and display APIs.

Its functionality closely overlaps with `EGL_EXT_image_dma_buf_import_modifiers`2 and `EGL_MESA_image_dma_buf_export`3. Unlike the EGL extensions, this extension does not require the use of a specific handle type (such as a dma_buf) for external memory and provides more explicit control of image creation.

##### Introduction to DRM Format Modifiers

A DRM format modifier is a 64-bit, vendor-prefixed, semi-opaque unsigned integer. Most modifiers represent a concrete, vendor-specific tiling format for images. Some exceptions are `DRM_FORMAT_MOD_LINEAR` (which is not vendor-specific); `DRM_FORMAT_MOD_NONE` (which is an alias of `DRM_FORMAT_MOD_LINEAR` due to historical accident); and `DRM_FORMAT_MOD_INVALID` (which does not represent a tiling format). The modifier’s vendor prefix consists of the 8 most significant bits. The canonical list of modifiers and vendor prefixes is found in `drm_fourcc.h` in the Linux kernel source. The other dominant source of modifiers are vendor kernel trees.

One goal of modifiers in the Linux ecosystem is to enumerate for each vendor a reasonably sized set of tiling formats that are appropriate for images shared across processes, APIs, and/or devices, where each participating component may possibly be from different vendors. A non-goal is to enumerate all tiling formats supported by all vendors. Some tiling formats used internally by vendors are inappropriate for sharing; no modifiers should be assigned to such tiling formats.

Modifier values typically do not describe memory layouts. More precisely, a modifier's lower 56 bits usually have no structure. Instead, modifiers name memory layouts; they name a small set of vendor-preferred layouts for image sharing. As a consequence, in each vendor namespace the modifier values are often sequentially allocated starting at 1.

Each modifier is usually supported by a single vendor and its name matches the pattern `{VENDOR}_FORMAT_MOD_*` or `DRM_FORMAT_MOD_{VENDOR}_*`. Examples are `I915_FORMAT_MOD_X_TILED` and `DRM_FORMAT_MOD_BROADCOM_VC4_T_TILED`. An exception is `DRM_FORMAT_MOD_LINEAR`, which is supported by most vendors.

Many APIs in Linux use modifiers to negotiate and specify the memory layout of shared images. For example, a Wayland compositor and Wayland client may, by relaying modifiers over the Wayland protocol `zwp_linux_dmabuf_v1`, negotiate a vendor-specific tiling format for a shared `wl_buffer`. The client may allocate the underlying memory for the `wl_buffer` with GBM, providing the chosen modifier to `gbm_bo_create_with_modifiers`. The client may then import the `wl_buffer` into Vulkan for producing image content, providing the resource’s dma_buf to VkImportMemoryFdInfoKHR and its modifier to VkImageDrmFormatModifierExplicitCreateInfoEXT. The compositor may then import the `wl_buffer` into OpenGL for sampling, providing the resource’s dma_buf and modifier to `eglCreateImage`. The compositor may also bypass OpenGL and submit the `wl_buffer` directly to the kernel’s display API, providing the dma_buf and modifier through `drm_mode_fb_cmd2`.

##### Format Translation

Modifier-capable APIs often pair modifiers with DRM formats, which are defined in `drm_fourcc.h`. However, `VK_EXT_image_drm_format_modifier` uses VkFormat instead of DRM formats. The application must convert between VkFormat and DRM format when it sends or receives a DRM format to or from an external API.

The mapping from VkFormat to DRM format is lossy. Therefore, when receiving a DRM format from an external API, often the application must use information from the external API to accurately map the DRM format to a VkFormat. For example, DRM formats do not distinguish between RGB and sRGB (as of 2018-03-28); external information is required to identify the image’s colorspace.

The mapping between VkFormat and DRM format is also incomplete. For some DRM formats there exist no corresponding Vulkan format, and for some Vulkan formats there exist no corresponding DRM format.

##### Usage Patterns

Three primary usage patterns are intended for this extension:

- Negotiation. The application negotiates with modifier-aware, external components to determine sets of image creation parameters supported among all components.

  In the Linux ecosystem, the negotiation usually assumes the image is a 2D, single-sampled, non-mipmapped, non-array image; this extension permits that assumption but does not require it. The result of the negotiation usually resembles a set of tuples such as (drmFormat, drmFormatModifier), where each participating component supports all tuples in the set.

  Many details of this negotiation—such as the protocol used during negotiation, the set of image creation parameters expressable in the protocol, and how the protocol chooses which process and which API will create the image—are outside the scope of this specification.

  In this extension, vkGetPhysicalDeviceFormatProperties2 with VkDrmFormatModifierPropertiesListEXT serves a primary role during the negotiation, and vkGetPhysicalDeviceImageFormatProperties2 with VkPhysicalDeviceImageDrmFormatModifierInfoEXT serves a secondary role.

- Import. The application imports an image with a modifier.

  In this pattern, the application receives from an external source the image’s memory and its creation parameters, which are often the result of the negotiation described above. Some image creation parameters are implicitly defined by the external source; for example, `VK_IMAGE_TYPE_2D` is often assumed. Some image creation parameters are usually explicit, such as the image’s `format`, `drmFormatModifier`, and `extent`; and each plane’s `offset` and `rowPitch`.

  Before creating the image, the application first verifies that the physical device supports the received creation parameters by querying vkGetPhysicalDeviceFormatProperties2 with VkDrmFormatModifierPropertiesListEXT and vkGetPhysicalDeviceImageFormatProperties2 with VkPhysicalDeviceImageDrmFormatModifierInfoEXT. Then the application creates the image by chaining VkImageDrmFormatModifierExplicitCreateInfoEXT and VkExternalMemoryImageCreateInfo onto VkImageCreateInfo.

- Export. The application creates an image and allocates its memory. Then the application exports to modifier-aware consumers the image’s memory handles; its creation parameters; its modifier; and the `offset`, `size`, and `rowPitch` of each memory plane.

  In this pattern, the Vulkan device is the authority for the image; it is the allocator of the image’s memory and the decider of the image’s creation parameters. When choosing the image’s creation parameters, the application usually chooses a tuple (format, drmFormatModifier) from the result of the negotiation described above. The negotiation’s result often contains multiple tuples that share the same format but differ in their modifier. In this case, the application should defer the choice of the image’s modifier to the Vulkan implementation by providing all such modifiers to VkImageDrmFormatModifierListCreateInfoEXT::`pDrmFormatModifiers`; and the implementation should choose from `pDrmFormatModifiers` the optimal modifier in consideration with the other image parameters.

  The application creates the image by chaining VkImageDrmFormatModifierListCreateInfoEXT and VkExternalMemoryImageCreateInfo onto VkImageCreateInfo. The protocol and APIs by which the application will share the image with external consumers will likely determine the value of VkExternalMemoryImageCreateInfo::`handleTypes`. The implementation chooses for the image an optimal modifier from VkImageDrmFormatModifierListCreateInfoEXT::`pDrmFormatModifiers`. The application then queries the implementation-chosen modifier with vkGetImageDrmFormatModifierPropertiesEXT, and queries the memory layout of each plane with vkGetImageSubresourceLayout.

  The application then allocates the image’s memory with VkMemoryAllocateInfo, adding chained extension structures for external memory; binds it to the image; and exports the memory, for example, with vkGetMemoryFdKHR.

  Finally, the application sends the image’s creation parameters, its modifier, its per-plane memory layout, and the exported memory handle to the external consumers. The details of how the application transmits this information to external consumers is outside the scope of this specification.

##### Prior Art

Extension `EGL_EXT_image_dma_buf_import`1 introduced the ability to create an `EGLImage` by importing for each plane a dma_buf, offset, and row pitch.

Later, extension `EGL_EXT_image_dma_buf_import_modifiers`2 introduced the ability to query which combination of formats and modifiers the implementation supports and to specify modifiers during creation of the `EGLImage`.

Extension `EGL_MESA_image_dma_buf_export`3 is the inverse of `EGL_EXT_image_dma_buf_import_modifiers`.

The Linux kernel modesetting API (KMS), when configuring the display’s framebuffer with `struct drm_mode_fb_cmd2`4, allows one to specify the frambuffer’s modifier as well as a per-plane memory handle, offset, and row pitch.

GBM, a graphics buffer manager for Linux, allows creation of a `gbm_bo` (that is, a graphics buffer object) by importing data similar to that in `EGL_EXT_image_dma_buf_import_modifiers`1; and symmetrically allows exporting the same data from the `gbm_bo`. See the references to modifier and plane in `gbm.h`5.

#### New Object Types

None.

#### New Enum Constants

- Extending VkResult:

  - `VK_ERROR_INVALID_DRM_FORMAT_MODIFIER_PLANE_LAYOUT_EXT`

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_DRM_FORMAT_MODIFIER_PROPERTIES_LIST_EXT`

  - `VK_STRUCTURE_TYPE_DRM_FORMAT_MODIFIER_PROPERTIES_EXT`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGE_DRM_FORMAT_MODIFIER_INFO_EXT`

  - `VK_STRUCTURE_TYPE_IMAGE_DRM_FORMAT_MODIFIER_LIST_CREATE_INFO_EXT`

  - `VK_STRUCTURE_TYPE_IMAGE_DRM_FORMAT_MODIFIER_EXPLICIT_CREATE_INFO_EXT`

  - `VK_STRUCTURE_TYPE_IMAGE_DRM_FORMAT_MODIFIER_PROPERTIES_EXT`

- Extending VkImageTiling:

  - `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`

- Extending VkImageAspectFlagBits:

  - `VK_IMAGE_ASPECT_MEMORY_PLANE_0_BIT_EXT`

  - `VK_IMAGE_ASPECT_MEMORY_PLANE_1_BIT_EXT`

  - `VK_IMAGE_ASPECT_MEMORY_PLANE_2_BIT_EXT`

  - `VK_IMAGE_ASPECT_MEMORY_PLANE_3_BIT_EXT`

#### New Enums

None.

#### New Structures

- Extends VkFormatProperties2:

  - VkDrmFormatModifierPropertiesListEXT

- Member of VkDrmFormatModifierPropertiesListEXT:

  - VkDrmFormatModifierPropertiesEXT

- Extends VkPhysicalDeviceImageFormatInfo2:

  - VkPhysicalDeviceImageDrmFormatModifierInfoEXT

- Extends VkImageCreateInfo:

  - VkImageDrmFormatModifierListCreateInfoEXT

  - VkImageDrmFormatModifierExplicitCreateInfoEXT

- Parameter to vkGetImageDrmFormatModifierPropertiesEXT:

  - VkImageDrmFormatModifierPropertiesEXT

#### New Functions

- vkGetImageDrmFormatModifierPropertiesEXT

#### Issues

1) Should this extension define a single DRM format modifier per `VkImage`? Or define one per plane?

+

RESOLVED: There exists a single DRM format modifier per `VkImage`.

DISCUSSION: Prior art, such as `EGL_EXT_image_dma_buf_import_modifiers`2, `struct drm_mode_fb_cmd2`4, and `struct gbm_import_fd_modifier_data`5, allows defining one modifier per plane. However, developers of the GBM and kernel APIs concede it was a mistake. Beginning in Linux 4.10, the kernel requires that the application provide the same DRM format modifier for each plane. (See Linux commit bae781b259269590109e8a4a8227331362b88212). And GBM provides an entry point, `gbm_bo_get_modifier`, for querying the modifier of the image but does not provide one to query the modifier of individual planes.

2) When creating an image with VkImageDrmFormatModifierExplicitCreateInfoEXT, which is typically used when importing an image, should the application explicitly provide the size of each plane?

+

RESOLVED: No. The application must not provide the size. To enforce this, the API requires that VkImageDrmFormatModifierExplicitCreateInfoEXT::`pPlaneLayouts->size` must be 0.

DISCUSSION: Prior art, such as `EGL_EXT_image_dma_buf_import_modifiers`2, `struct drm_mode_fb_cmd2`4, and `struct gbm_import_fd_modifier_data`5, omits from the API the size of each plane. Instead, the APIs infer each plane’s size from the import parameters, which include the image’s pixel format and a dma_buf, offset, and row pitch for each plane.

However, Vulkan differs from EGL and GBM with regards to image creation in the following ways:

Differences in Image Creation

- Undedicated allocation by default. When importing or exporting a set of dma_bufs as an `EGLImage` or `gbm_bo`, common practice mandates that each dma_buf’s memory be dedicated (in the sense of `VK_KHR_dedicated_allocation`) to the image (though not necessarily dedicated to a single plane). In particular, neither the GBM documentation nor the EGL extension specifications explicitly state this requirement, but in light of common practice this is likely due to under-specification rather than intentional omission. In contrast, `VK_EXT_image_drm_format_modifier` permits, but does not require, the implementation to require dedicated allocations for images created with `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`.

- Separation of image creation and memory allocation. When importing a set of dma_bufs as an `EGLImage` or `gbm_bo`, EGL and GBM create the image resource and bind it to memory (the dma_bufs) simultaneously. This allows EGL and GBM to query each dma_buf’s size during image creation. In Vulkan, image creation and memory allocation are independent unless a dedicated allocation is used (as in `VK_KHR_dedicated_allocation`). Therefore, without requiring dedicated allocation, Vulkan cannot query the size of each dma_buf (or other external handle) when calculating the image’s memory layout. Even if dedication allocation were required, Vulkan cannot calculate the image’s memory layout until after the image is bound to its dma_ufs.

The above differences complicate the potential inference of plane size in Vulkan. Consider the following problematic cases:

Problematic Plane Size Calculations

- Padding. Some plane of the image may require implementation-dependent padding.

- Metadata. For some modifiers, the image may have a metadata plane which requires a non-trivial calculation to determine its size.

- Mipmapped, array, and 3D images. The implementation may support `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT` for images whose `mipLevels`, `arrayLayers`, or `depth` is greater than 1. For such images with certain modifiers, the calculation of each plane’s size may be non-trivial.

However, an application-provided plane size solves none of the above problems.

For simplicity, consider an external image with a single memory plane. The implementation is obviously capable calculating the image’s size when its tiling is `VK_IMAGE_TILING_OPTIMAL`. Likewise, any reasonable implementation is capable of calculating the image’s size when its tiling uses a supported modifier.

Suppose that the external image’s size is smaller than the implementation-calculated size. If the application provided the external image’s size to vkCreateImage, the implementation would observe the mismatched size and recognize its inability to comprehend the external image’s layout (unless the implementation used the application-provided size to select a refinement of the tiling layout indicated by the modifier, which is strongly discouraged). The implementation would observe the conflict, and reject image creation with `VK_ERROR_INVALID_DRM_FORMAT_MODIFIER_PLANE_LAYOUT_EXT`. On the other hand, if the application did not provide the external image’s size to vkCreateImage, then the application would observe after calling vkGetImageMemoryRequirements that the external image’s size is less than the size required by the implementation. The application would observe the conflict and refuse to bind the `VkImage` to the external memory. In both cases, the result is explicit failure.

Suppose that the external image’s size is larger than the implementation-calculated size. If the application provided the external image’s size to vkCreateImage, for reasons similar to above the implementation would observe the mismatched size and recognize its inability to comprehend the image data residing in the extra size. The implementation, however, must assume that image data resides in the entire size provided by the application. The implementation would observe the conflict and reject image creation with `VK_ERROR_INVALID_DRM_FORMAT_MODIFIER_PLANE_LAYOUT_EXT`. On the other hand, if the application did not provide the external image’s size to vkCreateImage, then the application would observe after calling vkGetImageMemoryRequirements that the external image’s size is larger than the implementation-usable size. The application would observe the conflict and refuse to bind the `VkImage` to the external memory. In both cases, the result is explicit failure.

Therefore, an application-provided size provides no benefit, and this extension should not require it. This decision renders VkSubresourceLayout::`size` an unused field during image creation, and thus introduces a risk that implementations may require applications to submit sideband creation parameters in the unused field. To prevent implementations from relying on sideband data, this extension requires the application to set `size` to 0.

##### References

1. `EGL_EXT_image_dma_buf_import`

2. `EGL_EXT_image_dma_buf_import_modifiers`

3. `EGL_MESA_image_dma_buf_export`

4. `struct drm_mode_fb_cmd2`

5. `gbm.h`

##### Version History

- Revision 1, 2018-08-29 (Chad Versace)

  - First stable revision

#### VK_EXT_index_type_uint8

Name String

  `VK_EXT_index_type_uint8`

Extension Type

  Device extension

Registered Extension Number

  266

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Piers Daniell pdaniell-nv

Last Modified Date

  2019-05-02

IP Status

  No known IP claims.

Contributors

  - Jeff Bolz, NVIDIA

This extension allows uint8_t indices to be used with vkCmdBindIndexBuffer.

#### New Object Types

None

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_INDEX_TYPE_UINT8_FEATURES_EXT`

- Extending VkIndexType:

  - `VK_INDEX_TYPE_UINT8_EXT`

#### New Enums

None

#### New Structures

- VkPhysicalDeviceIndexTypeUint8FeaturesEXT

#### New Functions

None

#### New Built-In Variables

None

#### New SPIR-V Capabilities

None

#### Issues

None

#### Version History

- Revision 1, 2019-05-02 (Piers Daniell)

  - Internal revisions

#### VK_EXT_inline_uniform_block

Name String

  `VK_EXT_inline_uniform_block`

Extension Type

  Device extension

Registered Extension Number

  139

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

  - Requires `VK_KHR_maintenance1`

Contact

  - Daniel Rakos aqnuep

Last Modified Date

  2018-08-01

IP Status

  No known IP claims.

Contributors

  - Daniel Rakos, AMD

  - Jeff Bolz, NVIDIA

  - Slawomir Grajewski, Intel

  - Neil Henning, Codeplay

This extension introduces the ability to back uniform blocks directly with descriptor sets by storing inline uniform data within descriptor pool storage. Compared to push constants this new construct allows uniform data to be reused across multiple disjoint sets of draw or dispatch commands and may enable uniform data to be accessed with less indirections compared to uniforms backed by buffer memory.

#### New Object Types

None

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_INLINE_UNIFORM_BLOCK_FEATURES_EXT`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_INLINE_UNIFORM_BLOCK_PROPERTIES_EXT`

  - `VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET_INLINE_UNIFORM_BLOCK_EXT`

  - `VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_INLINE_UNIFORM_BLOCK_CREATE_INFO_EXT`

- Extending VkDescriptorType:

  - `VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT`

#### New Enums

None

#### New Structures

- VkPhysicalDeviceInlineUniformBlockFeaturesEXT

- VkPhysicalDeviceInlineUniformBlockPropertiesEXT

- VkWriteDescriptorSetInlineUniformBlockEXT

- VkDescriptorPoolInlineUniformBlockCreateInfoEXT

#### New Functions

None

#### New Built-In Variables

None

#### Issues

1) Do we need a new storage class for inline uniform blocks vs uniform blocks?

RESOLVED: No. The `Uniform` storage class is used to allow the same syntax used for both uniform buffers and inline uniform blocks.

2) Is the descriptor array index and array size expressed in terms of bytes or dwords for inline uniform block descriptors?

RESOLVED: In bytes, but both must be a multiple of 4, similar to how push constant ranges are specified. The `descriptorCount` of `VkDescriptorSetLayoutBinding` thus provides the total number of bytes a particular binding with an inline uniform block descriptor type can hold, while the `srcArrayElement`, `dstArrayElement`, and `descriptorCount` members of `VkWriteDescriptorSet`, `VkCopyDescriptorSet`, and `VkDescriptorUpdateTemplateEntry` (where applicable) specify the byte offset and number of bytes to write/copy to the binding’s backing store. Additionally, the `stride` member of `VkDescriptorUpdateTemplateEntry` is ignored for inline uniform blocks and a default value of one is used, meaning that the data to update inline uniform block bindings with must be contiguous in memory.

3) What layout rules apply for uniform blocks corresponding to inline constants?

RESOLVED: They use the same layout rules as uniform buffers.

4) Do we need to add non-uniform indexing features/properties as introduced by `VK_EXT_descriptor_indexing` for inline uniform blocks?

RESOLVED: No, because inline uniform blocks are not allowed to be “arrayed”. A single binding with an inline uniform block descriptor type corresponds to a single uniform block instance and the array indices inside that binding refer to individual offsets within the uniform block (see issue #2). However, this extension does introduce new features/properties about the level of support for update-after-bind inline uniform blocks.

5) Is the `descriptorBindingVariableDescriptorCount` feature introduced by `VK_EXT_descriptor_indexing` supported for inline uniform blocks?

RESOLVED: Yes, as long as other inline uniform block specific limits are respected.

6) Do the robustness guarantees of `robustBufferAccess` apply to inline uniform block accesses?

RESOLVED: No, similarly to push constants, as they are not backed by buffer memory like uniform buffers.

#### Version History

- Revision 1, 2018-08-01 (Daniel Rakos)

  - Internal revisions

#### VK_EXT_line_rasterization

Name String

  `VK_EXT_line_rasterization`

Extension Type

  Device extension

Registered Extension Number

  260

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Jeff Bolz jeffbolznv

Last Modified Date

  2019-05-09

IP Status

  No known IP claims.

Contributors

  - Jeff Bolz, NVIDIA

  - Allen Jensen, NVIDIA

  - Jason Ekstrand, Intel

This extension adds some line rasterization features that are commonly used in CAD applications and supported in other APIs like OpenGL. Bresenham-style line rasterization is supported, smooth rectangular lines (coverage to alpha) are supported, and stippled lines are supported for all three line rasterization modes.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_LINE_RASTERIZATION_FEATURES_EXT`

  - `VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_LINE_STATE_CREATE_INFO_EXT`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_LINE_RASTERIZATION_PROPERTIES_EXT`

- Extending VkDynamicState:

  - `VK_DYNAMIC_STATE_LINE_STIPPLE_EXT`

#### New Enums

- VkLineRasterizationModeEXT

#### New Structures

- VkPhysicalDeviceLineRasterizationFeaturesEXT

- VkPhysicalDeviceLineRasterizationPropertiesEXT

- VkPipelineRasterizationLineStateCreateInfoEXT

#### New Functions

- vkCmdSetLineStippleEXT

#### Issues

    (1) Do we need to support Bresenham-style and smooth lines with more than
        one rasterization sample? i.e. the equivalent of
        glDisable(GL_MULTISAMPLE) in OpenGL when the framebuffer has more than
        one sample?

    RESOLVED: Yes.
    For simplicity, Bresenham line rasterization carries forward a few
    restrictions from OpenGL, such as not supporting per-sample shading, alpha
    to coverage, or alpha to one.

#### Version History

- Revision 1, 2019-05-09 (Jeff Bolz)

  - Initial draft

#### VK_EXT_memory_budget

Name String

  `VK_EXT_memory_budget`

Extension Type

  Device extension

Registered Extension Number

  238

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Jeff Bolz jeffbolznv

Last Modified Date

  2018-10-08

Contributors

  - Jeff Bolz, NVIDIA

  - Jeff Juliano, NVIDIA

This extension adds support for querying the amount of memory used and the total memory budget for a memory heap. The values returned by this query are implementation-dependent and can depend on a variety of factors including operating system and system load.

The `heapBudget` values can be used as a guideline for how much total memory from each heap the process can use at any given time, before allocations may start failing or causing performance degradation. The values may change based on other activity in the system that is outside the scope and control of the Vulkan implementation.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_BUDGET_PROPERTIES_EXT`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceMemoryBudgetPropertiesEXT

#### New Functions

None.

#### Version History

- Revision 1, 2018-10-08 (Jeff Bolz)

  - Initial revision

#### VK_EXT_memory_priority

Name String

  `VK_EXT_memory_priority`

Extension Type

  Device extension

Registered Extension Number

  239

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Jeff Bolz jeffbolznv

Last Modified Date

  2018-10-08

Contributors

  - Jeff Bolz, NVIDIA

  - Jeff Juliano, NVIDIA

This extension adds a `priority` value specified at memory allocation time. On some systems with both device-local and non-device-local memory heaps, the implementation may transparently move memory from one heap to another when a heap becomes full (for example, when the total memory used across all processes exceeds the size of the heap). In such a case, this priority value may be used to determine which allocations are more likely to remain in device-local memory.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_PRIORITY_FEATURES_EXT`

  - `VK_STRUCTURE_TYPE_MEMORY_PRIORITY_ALLOCATE_INFO_EXT`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceMemoryPriorityFeaturesEXT

- VkMemoryPriorityAllocateInfoEXT

#### New Functions

None.

#### Version History

- Revision 1, 2018-10-08 (Jeff Bolz)

  - Initial revision

#### VK_EXT_metal_surface

Name String

  `VK_EXT_metal_surface`

Extension Type

  Instance extension

Registered Extension Number

  218

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_surface`

Contact

  - Dzmitry Malyshau kvark

Last Modified Date

  2018-10-01

IP Status

  No known IP claims.

Contributors

  - Dzmitry Malyshau, Mozilla Corp.

The `VK_EXT_metal_surface` extension is an instance extension. It provides a mechanism to create a VkSurfaceKHR object (defined by the `VK_KHR_surface` extension) from CAMetalLayer, which is the native rendering surface of Apple’s Metal framework.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_METAL_SURFACE_CREATE_INFO_EXT`

#### New Enums

None.

#### New Structures

- VkMetalSurfaceCreateInfoEXT

#### New Functions

- vkCreateMetalSurfaceEXT

#### Issues

None.

#### Version History

- Revision 1, 2018-10-01 (Dzmitry Malyshau)

  - Initial version

#### VK_EXT_pci_bus_info

Name String

  `VK_EXT_pci_bus_info`

Extension Type

  Device extension

Registered Extension Number

  213

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Matthaeus G. Chajdas anteru

Last Modified Date

  2018-12-10

IP Status

  No known IP claims.

Contributors

  - Matthaeus G. Chajdas, AMD

  - Daniel Rakos, AMD

This extension adds a new query to obtain PCI bus information about a physical device.

Not all physical devices have PCI bus information, either due to the device not being connected to the system through a PCI interface or due to platform specific restrictions and policies. Thus this extension is only expected to be supported by physical devices which can provide the information.

As a consequence, applications should always check for the presence of the extension string for each individual physical device for which they intend to issue the new query for and should not have any assumptions about the availability of the extension on any given platform.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PCI_BUS_INFO_PROPERTIES_EXT`

#### New Enums

None.

#### New Structures

- VkPhysicalDevicePCIBusInfoPropertiesEXT

#### New Functions

None.

#### Issues

None.

#### Examples

None.

#### Version History

- Revision 2, 2018-12-10 (Daniel Rakos)

  - Changed all members of the new structure to have the uint32_t type

- Revision 1, 2018-10-11 (Daniel Rakos)

  - Initial revision

#### VK_EXT_pipeline_creation_cache_control

Name String

  `VK_EXT_pipeline_creation_cache_control`

Extension Type

  Device extension

Registered Extension Number

  298

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Gregory Grebe grgrebe_amd

Last Modified Date

  2020-02-24

IP Status

  No known IP claims.

Contributors

  - Gregory Grebe, AMD

  - Tobias Hector, AMD

  - Matthaeus Chajdas, AMD

  - Mitch Singer, AMD

  - Spencer Fricke, Samsung Electronics

  - Stuart Smith, Imagination Technologies

  - Jeff Bolz, NVIDIA Corporation

  - Daniel Koch, NVIDIA Corporation

  - Dan Ginsburg, Valve Corporation

  - Jeff Leger, QUALCOMM

  - Michal Pietrasiuk, Intel

  - Jan-Harald Fredriksen, Arm Limited

This extension adds flags to `Vk*PipelineCreateInfo` and VkPipelineCacheCreateInfo structures with the aim of improving the predictability of pipeline creation cost. The goal is to provide information about potentially expensive hazards within the client driver during pipeline creation to the application before carrying them out rather than after.

#### Background

Pipeline creation is a costly operation, and the explicit nature of the Vulkan design means that cost is not hidden from the developer. Applications are also expected to schedule, prioritize, and load balance all calls for pipeline creation. It is strongly advised that applications create pipelines sufficiently ahead of their usage. Failure to do so will result in an unresponsive application, intermittent stuttering, or other poor user experiences. Proper usage of pipeline caches and/or derivative pipelines help mitigate this but is not assured to eliminate disruption in all cases. In the event that an ahead-of-time creation is not possible, considerations should be taken to ensure that the current execution context is suitable for the workload of pipeline creation including possible shader compilation.

Applications making API calls to create a pipeline must be prepared for any of the following to occur:

- OS/kernel calls to be made by the ICD

- Internal memory allocation not tracked by the `pAllocator` passed to `vkCreate*Pipelines`

- Internal thread synchronization or yielding of the current thread’s core

- Extremely long (multi-millisecond+), blocking, compilation times

- Arbitrary call stacks depths and stack memory usage

The job or task based game engines that are being developed to take advantage of explicit graphics APIs like Vulkan may behave exceptionally poorly if any of the above scenarios occur. However, most game engines are already built to "stream" in assets dynamically as the user plays the game. By adding control by way of VkPipelineCreateFlags, we can require an ICD to report back a failure in critical execution paths rather than forcing an unexpected wait.

Applications can prevent unexpected compilation by setting `VK_PIPELINE_CREATE_FAIL_ON_PIPELINE_COMPILE_REQUIRED_BIT_EXT` on `Vk*PipelineCreateInfo`::`flags`. When set, an ICD must not attempt pipeline or shader compilation to create the pipeline object. The ICD will return the error `VK_ERROR_PIPELINE_COMPILE_REQUIRED_EXT`. An ICD may still return a valid `VkPipeline` object by either re-using existing pre-compiled objects such as those from a pipeline cache, or derivative pipelines.

By default `vkCreate*Pipelines` calls must attempt to create all pipelines before returning. Setting `VK_PIPELINE_CREATE_EARLY_RETURN_ON_FAILURE_BIT_EXT` on `Vk*PipelineCreateInfo`::`flags` can be used as an escape hatch for batched pipeline creates.

Hidden locks also add to the unpredictability of the cost of pipeline creation. The most common case of locks inside the `vkCreate*Pipelines` is internal synchronization of the VkPipelineCache object. `VK_PIPELINE_CACHE_CREATE_EXTERNALLY_SYNCHRONIZED_BIT_EXT` can be set when calling vkCreatePipelineCache to state the cache is externally synchronized.

The hope is that armed with this information application and engine developers can leverage existing asset streaming systems to recover from "just-in-time" pipeline creation stalls.

#### New Enum Constants

- Extending VkPipelineCreateFlagBits:

  - `VK_PIPELINE_CREATE_FAIL_ON_PIPELINE_COMPILE_REQUIRED_BIT_EXT`

  - `VK_PIPELINE_CREATE_EARLY_RETURN_ON_FAILURE_BIT_EXT`

- Extending VkPipelineCacheCreateFlagBits:

  - `VK_PIPELINE_CACHE_CREATE_EXTERNALLY_SYNCHRONIZED_BIT_EXT`

- Extending VkResult:

  - `VK_ERROR_PIPELINE_COMPILE_REQUIRED_EXT`

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PIPELINE_CREATION_CACHE_CONTROL_FEATURES_EXT`

#### New Structures

- `VkPhysicalDevicePipelineCreationCacheControlFeaturesEXT`

#### Version History

- Revision 1, 2019-11-01 (Gregory Grebe)

  - Initial revision

- Revision 2, 2020-02-24 (Gregory Grebe)

  - Initial public revision

#### VK_EXT_pipeline_creation_feedback

Name String

  `VK_EXT_pipeline_creation_feedback`

Extension Type

  Device extension

Registered Extension Number

  193

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Jean-Francois Roy jfroy

Last Modified Date

  2019-03-12

IP Status

  No known IP claims.

Contributors

  - Jean-Francois Roy, Google

  - Hai Nguyen, Google

  - Andrew Ellem, Google

  - Bob Fraser, Google

  - Sujeevan Rajayogam, Google

  - Jan-Harald Fredriksen, ARM

  - Jeff Leger, Qualcomm Technologies, Inc.

  - Jeff Bolz, NVIDIA

  - Daniel Koch, NVIDIA

  - Neil Henning, AMD

This extension adds a mechanism to provide feedback to an application about pipeline creation, with the specific goal of allowing a feedback loop between build systems and in-the-field application executions to ensure effective pipeline caches are shipped to customers.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PIPELINE_CREATION_FEEDBACK_CREATE_INFO_EXT`

#### New Enums

- VkPipelineCreationFeedbackFlagBitsEXT

#### New Structures

- VkPipelineCreationFeedbackCreateInfoEXT

- VkPipelineCreationFeedbackEXT

#### New Functions

None.

#### Issues

None.

#### Examples

None.

#### Version History

- Revision 1, 2019-03-12 (Jean-Francois Roy)

  - Initial revision

#### VK_EXT_post_depth_coverage

Name String

  `VK_EXT_post_depth_coverage`

Extension Type

  Device extension

Registered Extension Number

  156

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Daniel Koch dgkoch

Last Modified Date

  2017-07-17

Interactions and External Dependencies

  - This extension requires the `SPV_KHR_post_depth_coverage` SPIR-V extension.

  - This extension requires `GL_ARB_post_depth_coverage` or `GL_EXT_post_depth_coverage` for GLSL-based source languages.

Contributors

  - Jeff Bolz, NVIDIA

This extension adds support for the following SPIR-V extension in Vulkan:

- `SPV_KHR_post_depth_coverage`

which allows the fragment shader to control whether values in the `SampleMask` built-in input variable reflect the coverage after the early per-fragment depth and stencil tests are applied.

This extension adds a new `PostDepthCoverage` execution mode under the `SampleMaskPostDepthCoverage` capability. When this mode is specified along with `EarlyFragmentTests`, the value of an input variable decorated with the `SampleMask` built-in reflects the coverage after the early fragment tests are applied. Otherwise, it reflects the coverage before the depth and stencil tests.

When using GLSL source-based shading languages, the `post_depth_coverage` layout qualifier from GL_ARB_post_depth_coverage or GL_EXT_post_depth_coverage maps to the `PostDepthCoverage` execution mode.

#### New Object Types

None.

#### New Enum Constants

None.

#### New Enums

None.

#### New Structures

None.

#### New Functions

None.

#### New Built-In Variables

None.

#### New Variable Decoration

None.

#### New SPIR-V Capabilities

- SampleMaskPostDepthCoverage

#### Issues

None yet.

#### Version History

- Revision 1, 2017-07-17 (Daniel Koch)

  - Internal revisions

#### VK_EXT_queue_family_foreign

Name String

  `VK_EXT_queue_family_foreign`

Extension Type

  Device extension

Registered Extension Number

  127

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_external_memory`

Contact

  - Chad Versace chadversary

Last Modified Date

  2017-11-01

IP Status

  No known IP claims.

Contributors

  - Chad Versace, Google

  - James Jones, NVIDIA

  - Jason Ekstrand, Intel

  - Jesse Hall, Google

  - Daniel Rakos, AMD

  - Ray Smith, ARM

This extension defines a special queue family, `VK_QUEUE_FAMILY_FOREIGN_EXT`, which can be used to transfer ownership of resources backed by external memory to foreign, external queues. This is similar to `VK_QUEUE_FAMILY_EXTERNAL_KHR`, defined in `VK_KHR_external_memory`. The key differences between the two are:

- The queues represented by `VK_QUEUE_FAMILY_EXTERNAL_KHR` must share the same physical device and the same driver version as the current VkInstance. `VK_QUEUE_FAMILY_FOREIGN_EXT` has no such restrictions. It can represent devices and drivers from other vendors, and can even represent non-Vulkan-capable devices.

- All resources backed by external memory support `VK_QUEUE_FAMILY_EXTERNAL_KHR`. Support for `VK_QUEUE_FAMILY_FOREIGN_EXT` is more restrictive.

- Applications should expect transitions to/from `VK_QUEUE_FAMILY_FOREIGN_EXT` to be more expensive than transitions to/from `VK_QUEUE_FAMILY_EXTERNAL_KHR`.

#### New Enum Constants

- Special constants:

  - `VK_QUEUE_FAMILY_FOREIGN_EXT`

#### Version History

- Revision 1, 2017-11-01 (Chad Versace)

  - Squashed internal revisions

#### VK_EXT_sample_locations

Name String

  `VK_EXT_sample_locations`

Extension Type

  Device extension

Registered Extension Number

  144

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Daniel Rakos drakos-amd

Last Modified Date

  2017-08-02

Contributors

  - Mais Alnasser, AMD

  - Matthaeus G. Chajdas, AMD

  - Maciej Jesionowski, AMD

  - Daniel Rakos, AMD

  - Slawomir Grajewski, Intel

  - Jeff Bolz, NVIDIA

  - Bill Licea-Kane, Qualcomm

This extension allows an application to modify the locations of samples within a pixel used in rasterization. Additionally, it allows applications to specify different sample locations for each pixel in a group of adjacent pixels, which can increase antialiasing quality (particularly if a custom resolve shader is used that takes advantage of these different locations).

It is common for implementations to optimize the storage of depth values by storing values that can be used to reconstruct depth at each sample location, rather than storing separate depth values for each sample. For example, the depth values from a single triangle may be represented using plane equations. When the depth value for a sample is needed, it is automatically evaluated at the sample location. Modifying the sample locations causes the reconstruction to no longer evaluate the same depth values as when the samples were originally generated, thus the depth aspect of a depth/stencil attachment must be cleared before rendering to it using different sample locations.

Some implementations may need to evaluate depth image values while performing image layout transitions. To accommodate this, instances of the VkSampleLocationsInfoEXT structure can be specified for each situation where an explicit or automatic layout transition has to take place. VkSampleLocationsInfoEXT can be chained from VkImageMemoryBarrier structures to provide sample locations for layout transitions performed by vkCmdWaitEvents and vkCmdPipelineBarrier calls, and VkRenderPassSampleLocationsBeginInfoEXT can be chained from VkRenderPassBeginInfo to provide sample locations for layout transitions performed implicitly by a render pass instance.

#### New Object Types

None.

#### New Enum Constants

- Extending VkImageCreateFlagBits:

  - `VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT`

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_SAMPLE_LOCATIONS_INFO_EXT`

  - `VK_STRUCTURE_TYPE_RENDER_PASS_SAMPLE_LOCATIONS_BEGIN_INFO_EXT`

  - `VK_STRUCTURE_TYPE_PIPELINE_SAMPLE_LOCATIONS_STATE_CREATE_INFO_EXT`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SAMPLE_LOCATIONS_PROPERTIES_EXT`

  - `VK_STRUCTURE_TYPE_MULTISAMPLE_PROPERTIES_EXT`

- Extending VkDynamicState:

  - `VK_DYNAMIC_STATE_SAMPLE_LOCATIONS_EXT`

#### New Enums

None.

#### New Structures

- VkSampleLocationEXT

- VkSampleLocationsInfoEXT

- VkAttachmentSampleLocationsEXT

- VkSubpassSampleLocationsEXT

- VkRenderPassSampleLocationsBeginInfoEXT

- VkPipelineSampleLocationsStateCreateInfoEXT

- VkPhysicalDeviceSampleLocationsPropertiesEXT

- VkMultisamplePropertiesEXT

#### New Functions

- vkCmdSetSampleLocationsEXT

- vkGetPhysicalDeviceMultisamplePropertiesEXT

#### Issues

None.

#### Version History

- Revision 1, 2017-08-02 (Daniel Rakos)

  - Internal revisions

#### VK_EXT_shader_demote_to_helper_invocation

Name String

  `VK_EXT_shader_demote_to_helper_invocation`

Extension Type

  Device extension

Registered Extension Number

  277

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Jeff Bolz jeffbolznv

Last Modified Date

  2019-06-01

IP Status

  No known IP claims.

Contributors

  - Jeff Bolz, NVIDIA

This extension adds Vulkan support for the `SPV_EXT_demote_to_helper_invocation` SPIR-V extension. That SPIR-V extension provides a new instruction `OpDemoteToHelperInvocationEXT` allowing shaders to "demote" a fragment shader invocation to behave like a helper invocation for its duration. The demoted invocation will have no further side effects and will not output to the framebuffer, but remains active and can participate in computing derivatives and in group operations. This is a better match for the "discard" instruction in HLSL.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_DEMOTE_TO_HELPER_INVOCATION_FEATURES_EXT`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceShaderDemoteToHelperInvocationFeaturesEXT

#### New Functions

None.

#### New SPIR-V Capability

- DemoteToHelperInvocationEXT

#### Issues

None.

#### Examples

None.

#### Version History

- Revision 1, 2019-06-01 (Jeff Bolz)

  - Initial draft

#### VK_EXT_shader_stencil_export

Name String

  `VK_EXT_shader_stencil_export`

Extension Type

  Device extension

Registered Extension Number

  141

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Dominik Witczak dominikwitczakamd

Last Modified Date

  2017-07-19

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Requires the `SPV_EXT_shader_stencil_export` SPIR-V extension.

Contributors

  - Dominik Witczak, AMD

  - Daniel Rakos, AMD

  - Rex Xu, AMD

This extension adds support for the SPIR-V extension `SPV_EXT_shader_stencil_export`, providing a mechanism whereby a shader may generate the stencil reference value per invocation. When stencil testing is enabled, this allows the test to be performed against the value generated in the shader.

#### Version History

- Revision 1, 2017-07-19 (Dominik Witczak)

  - Initial draft

#### VK_EXT_subgroup_size_control

Name String

  `VK_EXT_subgroup_size_control`

Extension Type

  Device extension

Registered Extension Number

  226

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.1

Contact

  - Neil Henning sheredom

Last Modified Date

  2019-03-05

Contributors

  - Jeff Bolz, NVIDIA

  - Jason Ekstrand, Intel

  - Sławek Grajewski, Intel

  - Jesse Hall, Google

  - Neil Henning, AMD

  - Daniel Koch, NVIDIA

  - Jeff Leger, Qualcomm

  - Graeme Leese, Broadcom

  - Allan MacKinnon, Google

  - Mariusz Merecki, Intel

  - Graham Wihlidal, Electronic Arts

#### Short Description

Enables an implementation to control the subgroup size by allowing a varying subgroup size and also specifying a required subgroup size.

#### Description

This extension extends the subgroup support in Vulkan 1.1 to allow an implementation to expose a varying subgroup size. Previously Vulkan exposed a single subgroup size per physical device, with the expectation that implementations will behave as if all subgroups have the same size. Some implementations may dispatch shaders with a varying subgroup size for different subgroups. As a result they could implicitly split a large subgroup into smaller subgroups or represent a small subgroup as a larger subgroup, some of whose invocations were inactive on launch.

To aid developers in understanding the performance characteristics of their programs, this extension exposes a minimum and maximum subgroup size that a physical device supports and a pipeline create flag to enable that pipeline to vary its subgroup size. If enabled, any `SubgroupSize` decorated variables in the SPIR-V shader modules provided to pipeline creation may vary between the minimum and maximum subgroup sizes.

An implementation is also optionally allowed to support specifying a required subgroup size for a given pipeline stage. Implementations advertise which stages support a required subgroup size, and any pipeline of a supported stage can be passed a VkPipelineShaderStageRequiredSubgroupSizeCreateInfoEXT structure to set the subgroup size for that shader stage of the pipeline. For compute shaders, this requires the developer to query the `maxComputeWorkgroupSubgroups` and ensure that:

\[s = {WorkGroupSize.x * WorkGroupSize.y * WorkgroupSize.z <= SubgroupSize * maxComputeWorkgroupSubgroups }\]

Developers can also specify a new pipeline shader stage create flag that requires the implementation to have fully populated subgroups within local workgroups. This requires the workgroup size in the X dimension to be a multiple of the subgroup size.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SUBGROUP_SIZE_CONTROL_FEATURES_EXT` (added in version 2)

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SUBGROUP_SIZE_CONTROL_PROPERTIES_EXT`

  - `VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_REQUIRED_SUBGROUP_SIZE_CREATE_INFO_EXT`

- Extending VkPipelineShaderStageCreateFlagBits:

  - `VK_PIPELINE_SHADER_STAGE_CREATE_ALLOW_VARYING_SUBGROUP_SIZE_BIT_EXT`

  - `VK_PIPELINE_SHADER_STAGE_CREATE_REQUIRE_FULL_SUBGROUPS_BIT_EXT`

#### New Structures

- VkPhysicalDeviceSubgroupSizeControlFeaturesEXT (added in version 2)

- VkPhysicalDeviceSubgroupSizeControlPropertiesEXT

- VkPipelineShaderStageRequiredSubgroupSizeCreateInfoEXT

#### Issues

None.

#### Version History

- Revision 1, 2019-03-05 (Neil Henning)

  - Initial draft

- Revision 2, 2019-07-26 (Jason Ekstrand)

  - Add the missing VkPhysicalDeviceSubgroupSizeControlFeaturesEXT for querying subgroup size control features.

#### VK_EXT_swapchain_colorspace

Name String

  `VK_EXT_swapchain_colorspace`

Extension Type

  Instance extension

Registered Extension Number

  105

Revision

  4

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_surface`

Contact

  - Courtney Goeltzenleuchter courtney-g

Last Modified Date

  2019-04-26

IP Status

  No known IP claims.

Contributors

  - Courtney Goeltzenleuchter, Google

#### New Enum Constants

- Extending VkColorSpaceKHR:

  - `VK_COLOR_SPACE_DISPLAY_P3_NONLINEAR_EXT` - supports the Display-P3 color space and applies an sRGB-like transfer function.

  - `VK_COLOR_SPACE_EXTENDED_SRGB_LINEAR_EXT` - supports the extended sRGB color space and applies a linear transfer function.

  - `VK_COLOR_SPACE_EXTENDED_SRGB_NONLINEAR_EXT` - supports the extended sRGB color space with an sRGB nonlinear transfer function.

  - `VK_COLOR_SPACE_DCI_P3_LINEAR_EXT` - supports the DCI-P3 color space and applies a linear OETF.

  - `VK_COLOR_SPACE_DCI_P3_NONLINEAR_EXT` - supports the DCI-P3 color space and applies the Gamma 2.6 OETF.

  - `VK_COLOR_SPACE_BT709_LINEAR_EXT` - supports the BT709 color space and applies a linear transfer function.

  - `VK_COLOR_SPACE_BT709_NONLINEAR_EXT` - supports the BT709 color space and applies the SMPTE 170M OETF.

  - `VK_COLOR_SPACE_BT2020_LINEAR_EXT` - supports the BT2020 color space and applies a linear OETF.

  - `VK_COLOR_SPACE_HDR10_ST2084_EXT` - supports HDR10 (BT2020 color space and applies the SMPTE ST2084 Perceptual Quantizer (PQ) OETF).

  - `VK_COLOR_SPACE_DOLBYVISION_EXT` - supports Dolby Vision (BT2020 color space, proprietary encoding, and applies the SMPTE ST2084 OETF).

  - `VK_COLOR_SPACE_HDR10_HLG_EXT` - supports HDR10 (BT2020 color space and applies the Hybrid Log Gamma (HLG) OETF).

  - `VK_COLOR_SPACE_ADOBERGB_LINEAR_EXT` - supports the AdobeRGB color space and applies a linear OETF.

  - `VK_COLOR_SPACE_ADOBERGB_NONLINEAR_EXT` - supports the AdobeRGB color space and applies the Gamma 2.2 OETF.

  - `VK_COLOR_SPACE_PASS_THROUGH_EXT` - color components used “as is”. Intended to allow application to supply data for color spaces not described here.

#### Issues

1) Does the spec need to specify which kinds of image formats support the color spaces?

RESOLVED: Pixel format is independent of color space (though some color spaces really want / need floating point color components to be useful). Therefore, do not plan on documenting what formats support which colorspaces. An application can call vkGetPhysicalDeviceSurfaceFormatsKHR to query what a particular implementation supports.

2) How does application determine if HW supports appropriate transfer function for a colorspace?

RESOLVED: Extension indicates that implementation must not do the OETF encoding if it is not sRGB. That responsibility falls to the application shaders. Any other native OETF / EOTF functions supported by an implementation can be described by separate extension.

#### Version History

- Revision 1, 2016-12-27 (Courtney Goeltzenleuchter)

  - Initial version

- Revision 2, 2017-01-19 (Courtney Goeltzenleuchter)

  - Add pass through and multiple options for BT2020.

  - Clean up some issues with equations not displaying properly.

- Revision 3, 2017-06-23 (Courtney Goeltzenleuchter)

  - Add extended sRGB non-linear enum.

- Revision 4, 2019-04-26 (Graeme Leese)

  - Clarify colorspace transfer function usage.

  - Refer to normative definitions in the Data Format Specification.

  - Clarify DCI-P3 and Display P3 usage.

#### VK_EXT_texel_buffer_alignment

Name String

  `VK_EXT_texel_buffer_alignment`

Extension Type

  Device extension

Registered Extension Number

  282

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Jeff Bolz jeffbolznv

Last Modified Date

  2019-06-06

IP Status

  No known IP claims.

Interactions and External Dependencies
Contributors

  - Jeff Bolz, NVIDIA

This extension adds more expressive alignment requirements for uniform and storage texel buffers. Some implementations have single texel alignment requirements that can’t be expressed via VkPhysicalDeviceLimits::`minTexelBufferOffsetAlignment`.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TEXEL_BUFFER_ALIGNMENT_FEATURES_EXT`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TEXEL_BUFFER_ALIGNMENT_PROPERTIES_EXT`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceTexelBufferAlignmentFeaturesEXT

- VkPhysicalDeviceTexelBufferAlignmentPropertiesEXT

#### New Functions

None.

#### Issues

#### Version History

- Revision 1, 2019-06-06 (Jeff Bolz)

  - Initial draft

#### VK_EXT_texture_compression_astc_hdr

Name String

  `VK_EXT_texture_compression_astc_hdr`

Extension Type

  Device extension

Registered Extension Number

  67

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Jan-Harald Fredriksen janharaldfredriksen-arm

Last Modified Date

  2019-05-28

IP Status

  No known issues.

Contributors

  - Jan-Harald Fredriksen, Arm

This extension adds support for textures compressed using the Adaptive Scalable Texture Compression (ASTC) High Dynamic Range (HDR) profile.

When this extension is enabled, the HDR profile is supported for all ASTC formats listed in ASTC Compressed Image Formats.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TEXTURE_COMPRESSION_ASTC_HDR_FEATURES_EXT`

- Extending VkFormat:

  - `VK_FORMAT_ASTC_4x4_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_5x4_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_5x5_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_6x5_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_6x6_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_8x5_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_8x6_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_8x8_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_10x5_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_10x6_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_10x8_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_10x10_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_12x10_SFLOAT_BLOCK_EXT`

  - `VK_FORMAT_ASTC_12x12_SFLOAT_BLOCK_EXT`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceTextureCompressionASTCHDRFeaturesEXT

#### New Functions

None.

#### Issues

1) Should we add a feature or limit for this functionality?

Yes. It is consistent with the ASTC LDR support to add a feature like textureCompressionASTC_HDR.

The feature is strictly speaking redundant as long as this is just an extension; it would be sufficient to just enable the extension. But adding the feature is more forward-looking if wanted to make this an optional core feature in the future.

2) Should we introduce new format enums for HDR?

Yes. Vulkan 1.0 describes the ASTC format enums as UNORM, e.g. `VK_FORMAT_ASTC_4x4_UNORM_BLOCK`, so it’s confusing to make these contain HDR data. Note that the OpenGL (ES) extensions did not make this distinction because a single ASTC HDR texture may contain both unorm and float blocks. Implementations may not be able to distinguish between LDR and HDR ASTC textures internally and just treat them as the same format, i.e. if this extension is supported then sampling from a `VK_FORMAT_ASTC_4x4_UNORM_BLOCK` image format may return HDR results. Applications can get predictable results by using the appropriate image format.

#### Version History

- Revision 1, 2019-05-28 (Jan-Harald Fredriksen)

  - Initial version

#### VK_EXT_tooling_info

Name String

  `VK_EXT_tooling_info`

Extension Type

  Device extension

Registered Extension Number

  246

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Tobias Hector tobski

Last Modified Date

  2018-11-05

Contributors

  - Rolando Caloca

  - Matthaeus Chajdas

  - Baldur Karlsson

  - Daniel Rakos

When an error occurs during application development, a common question is "What tools are actually running right now?" This extension adds the ability to query that information directly from the Vulkan implementation.

Outdated versions of one tool might not play nicely with another, or perhaps a tool is not actually running when it should have been. Trying to figure that out can cause headaches as it’s necessary to consult each known tool to figure out what’s going on - in some cases the tool might not even be known.

Typically, the expectation is that developers will simply print out this information for visual inspection when an issue occurs, however a small amount of semantic information about what the tool is doing is provided to help identify it programmatically. For example, if the advertised limits or features of an implementation are unexpected, is there a tool active which modifies these limits? Or if an application is providing debug markers, but the implementation is not actually doing anything with that information, this can quickly point that out.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TOOL_PROPERTIES_EXT`

#### New Enums

- VkToolPurposeFlagBitsEXT

#### New Structures

- VkPhysicalDeviceToolPropertiesEXT

#### New Functions

- vkGetPhysicalDeviceToolPropertiesEXT

#### Examples

Printing Tool Information

    uint32_t num_tools;
    VkPhysicalDeviceToolPropertiesEXT *pToolProperties;
    vkGetPhysicalDeviceToolPropertiesEXT(physicalDevice, &num_tools, NULL);

    pToolProperties = (VkPhysicalDeviceToolPropertiesEXT*)malloc(sizeof(VkPhysicalDeviceToolPropertiesEXT) * num_tools);

    vkGetPhysicalDeviceToolPropertiesEXT(physicalDevice, &num_tools, pToolProperties);

    for (int i = 0; i < num_tools; ++i) {
        printf("%s:\n", pToolProperties[i].name);
        printf("Version:\n");
        printf("%s:\n", pToolProperties[i].version);
        printf("Description:\n");
        printf("\t%s\n", pToolProperties[i].description);
        printf("Purposes:\n");
        printf("\t%s\n", VkToolPurposeFlagBitsEXT_to_string(pToolProperties[i].purposes));
        if (strnlen_s(pToolProperties[i].layer,VK_MAX_EXTENSION_NAME_SIZE) > 0) {
            printf("Corresponding Layer:\n");
            printf("\t%s\n", pToolProperties[i].layer);
        }
    }

#### Issues

1) Why is this information separate from the layer mechanism?

Some tooling may be built into a driver, or be part of the Vulkan loader etc. - and so tying this information directly to layers would’ve been awkward at best.

#### Version History

- Revision 1, 2018-11-05 (Tobias Hector)

  - Initial draft

#### VK_EXT_transform_feedback

Name String

  `VK_EXT_transform_feedback`

Extension Type

  Device extension

Registered Extension Number

  29

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Piers Daniell pdaniell-nv

Last Modified Data

  2018-10-09

Contributors

  - Baldur Karlsson, Valve

  - Boris Zanin, Mobica

  - Daniel Rakos, AMD

  - Donald Scorgie, Imagination

  - Henri Verbeet, CodeWeavers

  - Jan-Harald Fredriksen, Arm

  - Jason Ekstrand, Intel

  - Jeff Bolz, NVIDIA

  - Jesse Barker, Unity

  - Jesse Hall, Google

  - Pierre-Loup Griffais, Valve

  - Philip Rebohle, DXVK

  - Ruihao Zhang, Qualcomm

  - Samuel Pitoiset, Valve

  - Slawomir Grajewski, Intel

  - Stu Smith, Imagination Technologies

This extension adds transform feedback to the Vulkan API by exposing the SPIR-V `TransformFeedback` and `GeometryStreams` capabilities to capture vertex, tessellation or geometry shader outputs to one or more buffers. It adds API functionality to bind transform feedback buffers to capture the primitives emitted by the graphics pipeline from SPIR-V outputs decorated for transform feedback. The transform feedback capture can be paused and resumed by way of storing and retrieving a byte counter. The captured data can be drawn again where the vertex count is derived from the byte counter without CPU intervention. If the implementation is capable, a vertex stream other than zero can be rasterized.

All these features are designed to match the full capabilities of OpenGL core transform feedback functionality and beyond. Many of the features are optional to allow base OpenGL ES GPUs to also implement this extension.

The primary purpose of the functionality exposed by this extension is to support translation layers from other 3D APIs. This functionality is not considered forward looking, and is not expected to be promoted to a KHR extension or to core Vulkan. Unless this is needed for translation, it is recommended that developers use alternative techniques of using the GPU to process and capture vertex data.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TRANSFORM_FEEDBACK_FEATURES_EXT`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TRANSFORM_FEEDBACK_PROPERTIES_EXT`

  - `VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_STREAM_CREATE_INFO_EXT`

- Extending VkQueryType:

  - `VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT`

- Extending VkBufferUsageFlagBits:

  - `VK_BUFFER_USAGE_TRANSFORM_FEEDBACK_BUFFER_BIT_EXT`

  - `VK_BUFFER_USAGE_TRANSFORM_FEEDBACK_COUNTER_BUFFER_BIT_EXT`

- Extending VkAccessFlagBits:

  - `VK_ACCESS_TRANSFORM_FEEDBACK_WRITE_BIT_EXT`

  - `VK_ACCESS_TRANSFORM_FEEDBACK_COUNTER_READ_BIT_EXT`

  - `VK_ACCESS_TRANSFORM_FEEDBACK_COUNTER_WRITE_BIT_EXT`

- Extending VkPipelineStageFlagBits:

  - `VK_PIPELINE_STAGE_TRANSFORM_FEEDBACK_BIT_EXT`

#### New Enums

- VkPipelineRasterizationStateStreamCreateFlagsEXT

#### New Structures

- Extending VkPhysicalDeviceFeatures2:

  - VkPhysicalDeviceTransformFeedbackFeaturesEXT

- Extending VkPhysicalDeviceProperties2:

  - VkPhysicalDeviceTransformFeedbackPropertiesEXT

- Extending VkPipelineRasterizationStateCreateInfo

  - VkPipelineRasterizationStateStreamCreateInfoEXT

#### New Functions

- vkCmdBindTransformFeedbackBuffersEXT

- vkCmdBeginTransformFeedbackEXT

- vkCmdEndTransformFeedbackEXT

- vkCmdBeginQueryIndexedEXT

- vkCmdEndQueryIndexedEXT

- vkCmdDrawIndirectByteCountEXT

#### Issues

1) Should we include pause/resume functionality?

RESOLVED: Yes, this is needed to ease layering other APIs which have this functionality. To pause use `vkCmdEndTransformFeedbackEXT` and provide valid buffer handles in the `pCounterBuffers` array and offsets in the `pCounterBufferOffsets` array for the implementation to save the resume points. Then to resume use `vkCmdBeginTransformFeedbackEXT` with the previous `pCounterBuffers` and `pCounterBufferOffsets` values. Between the pause and resume there needs to be a memory barrier for the counter buffers with a source access of `VK_ACCESS_TRANSFORM_FEEDBACK_COUNTER_WRITE_BIT_EXT` at pipeline stage `VK_PIPELINE_STAGE_TRANSFORM_FEEDBACK_BIT_EXT` to a destination access of `VK_ACCESS_TRANSFORM_FEEDBACK_COUNTER_READ_BIT_EXT` at pipeline stage `VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT`.

2) How does this interact with multiview?

RESOLVED: Transform feedback cannot be made active in a render pass with multiview enabled.

3) How should queries be done?

RESOLVED: There is a new query type `VK_QUERY_TYPE_TRANSFORM_FEEDBACK_STREAM_EXT`. A query pool created with this type will capture 2 integers - numPrimitivesWritten and numPrimitivesNeeded - for the specified vertex stream output from the last vertex processing stage. The vertex stream output queried is zero by default, but can be specified with the new `vkCmdBeginQueryIndexedEXT` and `vkCmdEndQueryIndexedEXT` commands.

#### Version History

- Revision 1, 2018-10-09 (Piers Daniell)

  - Internal revisions

#### VK_EXT_validation_cache

Name String

  `VK_EXT_validation_cache`

Extension Type

  Device extension

Registered Extension Number

  161

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Cort Stratton cdwfs

Last Modified Date

  2017-08-29

IP Status

  No known IP claims.

Contributors

  - Cort Stratton, Google

  - Chris Forbes, Google

This extension provides a mechanism for caching the results of potentially expensive internal validation operations across multiple runs of a Vulkan application. At the core is the VkValidationCacheEXT object type, which is managed similarly to the existing VkPipelineCache.

The new struct VkShaderModuleValidationCacheCreateInfoEXT can be included in the `pNext` chain at vkCreateShaderModule time. It contains a VkValidationCacheEXT to use when validating the VkShaderModule.

#### New Object Types

- VkValidationCacheEXT

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_VALIDATION_CACHE_CREATE_INFO_EXT`

  - `VK_STRUCTURE_TYPE_SHADER_MODULE_VALIDATION_CACHE_CREATE_INFO_EXT`

#### New Enums

- VkValidationCacheHeaderVersionEXT

- VkValidationCacheCreateFlagsEXT

#### New Structures

- VkValidationCacheCreateInfoEXT

- VkShaderModuleValidationCacheCreateInfoEXT

#### New Functions

- vkCreateValidationCacheEXT

- vkDestroyValidationCacheEXT

- vkMergeValidationCachesEXT

- vkGetValidationCacheDataEXT

#### Issues

None.

#### Version History

- Revision 1, 2017-08-29 (Cort Stratton)

  - Initial draft

#### VK_EXT_validation_features

Name String

  `VK_EXT_validation_features`

Extension Type

  Instance extension

Registered Extension Number

  248

Revision

  3

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Karl Schultz karl-lunarg

Last Modified Date

  2018-11-14

IP Status

  No known IP claims.

Contributors

  - Karl Schultz, LunarG

  - Dave Houlton, LunarG

  - Mark Lobodzinski, LunarG

  - Camden Stocker, LunarG

  - Tony Barbour, LunarG

This extension provides the VkValidationFeaturesEXT struct that can be included in the `pNext` chain of the VkInstanceCreateInfo structure passed as the `pCreateInfo` parameter of vkCreateInstance. The structure contains an array of VkValidationFeatureEnableEXT enum values that enable specific validation features that are disabled by default. The structure also contains an array of VkValidationFeatureDisableEXT enum values that disable specific validation layer features that are enabled by default.

| Note The `VK_EXT_validation_features` extension subsumes all the functionality provided in the `VK_EXT_validation_flags` extension.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_VALIDATION_FEATURES_EXT`

#### New Enums

- VkValidationFeatureEnableEXT

- VkValidationFeatureDisableEXT

#### New Structures

- VkValidationFeaturesEXT

#### New Functions

None.

#### Issues

None.

#### Version History

- Revision 1, 2018-11-14 (Karl Schultz)

  - Initial revision

- Revision 2, 2019-08-06 (Mark Lobodzinski)

  - Add Best Practices enable

- Revision 3, 2020-03-04 (Tony Barbour)

  - Add Debug Printf enable

#### VK_EXT_vertex_attribute_divisor

Name String

  `VK_EXT_vertex_attribute_divisor`

Extension Type

  Device extension

Registered Extension Number

  191

Revision

  3

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Vikram Kushwaha vkushwaha

Last Modified Date

  2018-08-03

IP Status

  No known IP claims.

Contributors

  - Vikram Kushwaha, NVIDIA

  - Jason Ekstrand, Intel

This extension allows instance-rate vertex attributes to be repeated for certain number of instances instead of advancing for every instance when instanced rendering is enabled.

#### New Object Types

None.

#### New Enum Constants

Extending VkStructureType:

- `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VERTEX_ATTRIBUTE_DIVISOR_PROPERTIES_EXT`

- `VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_DIVISOR_STATE_CREATE_INFO_EXT`

- `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VERTEX_ATTRIBUTE_DIVISOR_FEATURES_EXT`

#### New Enums

None.

#### New Structures

- Extending VkPipelineVertexInputStateCreateInfo:

  - VkPipelineVertexInputDivisorStateCreateInfoEXT

- VkPhysicalDeviceVertexAttributeDivisorPropertiesEXT

- VkVertexInputBindingDivisorDescriptionEXT

- Extending VkPhysicalDeviceFeatures2:

  - VkPhysicalDeviceVertexAttributeDivisorFeaturesEXT

#### New Functions

None.

#### Issues

1) What is the effect of a non-zero value for `firstInstance`?

RESOLVED: The Vulkan API should follow the OpenGL convention and offset attribute fetching by `firstInstance` while computing vertex attribute offsets.

2) Should zero be an allowed divisor?

RESOLVED: Yes. A zero divisor means the vertex attribute is repeated for all instances.

#### Examples

To create a vertex binding such that the first binding uses instanced rendering and the same attribute is used for every 4 draw instances, an application could use the following set of structures:

        const VkVertexInputBindingDivisorDescriptionEXT divisorDesc =
        {
            0,
            4
        };

        const VkPipelineVertexInputDivisorStateCreateInfoEXT divisorInfo =
        {
            VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_DIVISOR_STATE_CREATE_INFO_EXT, // sType
            NULL,                                                             // pNext
            1,                                                                // vertexBindingDivisorCount
            &divisorDesc                                                      // pVertexBindingDivisors
        }

        const VkVertexInputBindingDescription binding =
        {
            0,                                                                // binding
            sizeof(Vertex),                                                   // stride
            VK_VERTEX_INPUT_RATE_INSTANCE                                     // inputRate
        };

        const VkPipelineVertexInputStateCreateInfo viInfo =
        {
            VK_STRUCTURE_TYPE_PIPELINE_VERTEX_INPUT_CREATE_INFO,              // sType
            &divisorInfo,                                                     // pNext
            ...
        };
        //...

#### Version History

- Revision 1, 2017-12-04 (Vikram Kushwaha)

  - First Version

- Revision 2, 2018-07-16 (Jason Ekstrand)

  - Adjust the interaction between `divisor` and `firstInstance` to match the OpenGL convention.

  - Disallow divisors of zero.

- Revision 3, 2018-08-03 (Vikram Kushwaha)

  - Allow a zero divisor.

  - Add a physical device features structure to query/enable this feature.

#### VK_EXT_ycbcr_image_arrays

Name String

  `VK_EXT_ycbcr_image_arrays`

Extension Type

  Device extension

Registered Extension Number

  253

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_sampler_ycbcr_conversion`

Contact

  - Piers Daniell pdaniell-nv

Last Modified Date

  2019-01-15

Contributors

  - Piers Daniell, NVIDIA

This extension allows images of a format that requires Y′CBCR conversion to be created with multiple array layers, which is otherwise restricted.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_YCBCR_IMAGE_ARRAYS_FEATURES_EXT`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceYcbcrImageArraysFeaturesEXT

#### New Functions

None.

#### Version History

- Revision 1, 2019-01-15 (Piers Daniell)

  - Initial revision

#### VK_AMD_buffer_marker

Name String

  `VK_AMD_buffer_marker`

Extension Type

  Device extension

Registered Extension Number

  180

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Daniel Rakos drakos-amd

Last Modified Date

  2018-01-26

IP Status

  No known IP claims.

Contributors

  - Matthaeus G. Chajdas, AMD

  - Jaakko Konttinen, AMD

  - Daniel Rakos, AMD

This extension adds a new operation to execute pipelined writes of small marker values into a `VkBuffer` object.

The primary purpose of these markers is to facilitate the development of debugging tools for tracking which pipelined command contributed to device loss.

#### New Object Types

None.

#### New Enum Constants

None.

#### New Enums

None.

#### New Structures

None.

#### New Functions

- vkCmdWriteBufferMarkerAMD

#### Examples

None.

#### Version History

- Revision 1, 2018-01-26 (Jaakko Konttinen)

  - Initial revision

#### VK_AMD_device_coherent_memory

Name String

  `VK_AMD_device_coherent_memory`

Extension Type

  Device extension

Registered Extension Number

  230

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Tobias Hector tobski

Last Modified Date

  2019-02-04

Contributors

  - Ping Fu, AMD

  - Timothy Lottes, AMD

  - Tobias Hector, AMD

This extension adds the device coherent and device uncached memory types. Any device accesses to device coherent memory are automatically made visible to any other device access. Device uncached memory indicates to applications that caches are disabled for a particular memory type, which guarantees device coherence.

Device coherent and uncached memory are expected to have lower performance for general access than non-device coherent memory, but can be useful in certain scenarios; particularly so for debugging.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_COHERENT_MEMORY_FEATURES_AMD`

- Extending VkMemoryPropertyFlagBits:

  - `VK_MEMORY_PROPERTY_DEVICE_COHERENT_BIT_AMD`

  - `VK_MEMORY_PROPERTY_DEVICE_UNCACHED_BIT_AMD`

#### Version History

- Revision 1, 2019-02-04 (Tobias Hector)

  - Initial revision

#### VK_AMD_display_native_hdr

Name String

  `VK_AMD_display_native_hdr`

Extension Type

  Device extension

Registered Extension Number

  214

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

  - Requires `VK_KHR_get_surface_capabilities2`

  - Requires `VK_KHR_swapchain`

Contact

  - Matthaeus G. Chajdas anteru

Last Modified Date

  2018-12-18

IP Status

  No known IP claims.

Contributors

  - Matthaeus G. Chajdas, AMD

  - Aaron Hagan, AMD

  - Aric Cyr, AMD

  - Timothy Lottes, AMD

  - Derrick Owens, AMD

  - Daniel Rakos, AMD

This extension introduces the following display native HDR features to Vulkan:

- A new VkColorSpaceKHR enum for setting the native display colorspace. For example, this color space would be set by the swapchain to use the native color space in Freesync2 displays.

- Local dimming control

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_DISPLAY_NATIVE_HDR_SURFACE_CAPABILITIES_AMD`

  - `VK_STRUCTURE_TYPE_SWAPCHAIN_DISPLAY_NATIVE_HDR_CREATE_INFO_AMD`

- Extending VkColorSpaceKHR:

  - `VK_COLOR_SPACE_DISPLAY_NATIVE_AMD`

#### New Enums

None.

#### New Structures

- VkDisplayNativeHdrSurfaceCapabilitiesAMD

- VkSwapchainDisplayNativeHdrCreateInfoAMD

#### New Functions

- vkSetLocalDimmingAMD

#### Issues

None.

#### Examples

None.

#### Version History

- Revision 1, 2018-12-18 (Daniel Rakos)

  - Initial revision

#### VK_AMD_gcn_shader

Name String

  `VK_AMD_gcn_shader`

Extension Type

  Device extension

Registered Extension Number

  26

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Dominik Witczak dominikwitczakamd

Last Modified Date

  2016-05-30

IP Status

  No known IP claims.

Contributors

  - Dominik Witczak, AMD

  - Daniel Rakos, AMD

  - Rex Xu, AMD

  - Graham Sellers, AMD

This extension adds support for the following SPIR-V extension in Vulkan:

- `SPV_AMD_gcn_shader`

| editing-note Shouldn’t the SPV extension be in the Interactions and External Dependencies block?

#### Version History

- Revision 1, 2016-05-30 (Dominik Witczak)

  - Initial draft

#### VK_AMD_memory_overallocation_behavior

Name String

  `VK_AMD_memory_overallocation_behavior`

Extension Type

  Device extension

Registered Extension Number

  190

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Martin Dinkov mdinkov

Last Modified Date

  2018-09-19

IP Status

  No known IP claims.

Contributors

  - Martin Dinkov, AMD

  - Matthaeus Chajdas, AMD

  - Daniel Rakos, AMD

  - Jon Campbell, AMD

This extension allows controlling whether explicit overallocation beyond the device memory heap sizes (reported by VkPhysicalDeviceMemoryProperties) is allowed or not. Overallocation may lead to performance loss and is not supported for all platforms.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_DEVICE_MEMORY_OVERALLOCATION_CREATE_INFO_AMD`

#### New Enums

- VkMemoryOverallocationBehaviorAMD

#### New Structures

- VkDeviceMemoryOverallocationCreateInfoAMD

#### New Functions

None.

#### Examples

None.

#### Version History

- Revision 1, 2018-09-19 (Martin Dinkov)

  - Initial draft.

#### VK_AMD_mixed_attachment_samples

Name String

  `VK_AMD_mixed_attachment_samples`

Extension Type

  Device extension

Registered Extension Number

  137

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Matthaeus G. Chajdas anteru

Last Modified Date

  2017-07-24

Contributors

  - Mais Alnasser, AMD

  - Matthaeus G. Chajdas, AMD

  - Maciej Jesionowski, AMD

  - Daniel Rakos, AMD

This extension enables applications to use multisampled rendering with a depth/stencil sample count that is larger than the color sample count. Having a depth/stencil sample count larger than the color sample count allows maintaining geometry and coverage information at a higher sample rate than color information. All samples are depth/stencil tested, but only the first color sample count number of samples get a corresponding color output.

#### New Object Types

None.

#### New Enum Constants

None.

#### New Enums

None.

#### New Structures

None.

#### New Functions

None.

#### Issues

None.

#### Version History

- Revision 1, 2017-07-24 (Daniel Rakos)

  - Internal revisions

#### VK_AMD_pipeline_compiler_control

Name String

  `VK_AMD_pipeline_compiler_control`

Extension Type

  Device extension

Registered Extension Number

  184

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Matthaeus G. Chajdas anteru

Last Modified Date

  2019-07-26

IP Status

  No known IP claims.

Contributors

  - Matthaeus G. Chajdas, AMD

  - Daniel Rakos, AMD

  - Maciej Jesionowski, AMD

  - Tobias Hector, AMD

This extension introduces VkPipelineCompilerControlCreateInfoAMD structure that can be chained to a pipeline’s create info to specify additional flags that affect pipeline compilation.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PIPELINE_COMPILER_CONTROL_CREATE_INFO_AMD`

#### New Enums

- VkPipelineCompilerControlFlagBitsAMD

#### New Structures

- VkPipelineCompilerControlCreateInfoAMD

#### New Functions

None.

#### Issues

None.

#### Examples

None.

#### Version History

- Revision 1, 2019-07-26 (Tobias Hector)

  - Initial revision.

#### VK_AMD_rasterization_order

Name String

  `VK_AMD_rasterization_order`

Extension Type

  Device extension

Registered Extension Number

  19

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Daniel Rakos drakos-amd

Last Modified Date

  2016-04-25

IP Status

  No known IP claims.

Contributors

  - Matthaeus G. Chajdas, AMD

  - Jaakko Konttinen, AMD

  - Daniel Rakos, AMD

  - Graham Sellers, AMD

  - Dominik Witczak, AMD

This extension introduces the possibility for the application to control the order of primitive rasterization. In unextended Vulkan, the following stages are guaranteed to execute in API order:

- depth bounds test

- stencil test, stencil op, and stencil write

- depth test and depth write

- occlusion queries

- blending, logic op, and color write

This extension enables applications to opt into a relaxed, implementation defined primitive rasterization order that may allow better parallel processing of primitives and thus enabling higher primitive throughput. It is applicable in cases where the primitive rasterization order is known to not affect the output of the rendering or any differences caused by a different rasterization order are not a concern from the point of view of the application’s purpose.

A few examples of cases when using the relaxed primitive rasterization order would not have an effect on the final rendering:

- If the primitives rendered are known to not overlap in framebuffer space.

- If depth testing is used with a comparison operator of `VK_COMPARE_OP_LESS`, `VK_COMPARE_OP_LESS_OR_EQUAL`, `VK_COMPARE_OP_GREATER`, or `VK_COMPARE_OP_GREATER_OR_EQUAL`, and the primitives rendered are known to not overlap in clip space.

- If depth testing is not used and blending is enabled for all attachments with a commutative blend operator.

#### New Object Types

None

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PIPELINE_RASTERIZATION_STATE_RASTERIZATION_ORDER_AMD`

#### New Enums

- VkRasterizationOrderAMD

#### New Structures

- VkPipelineRasterizationStateRasterizationOrderAMD

#### New Functions

None

#### Issues

1) How is this extension useful to application developers?

RESOLVED: Allows them to increase primitive throughput for cases when strict API order rasterization is not important due to the nature of the content, the configuration used, or the requirements towards the output of the rendering.

2) How does this extension interact with content optimizations aiming to reduce overdraw by appropriately ordering the input primitives?

RESOLVED: While the relaxed rasterization order might somewhat limit the effectiveness of such content optimizations, most of the benefits of it are expected to be retained even when the relaxed rasterization order is used, so applications should still apply these optimizations even if they intend to use the extension.

3) Are there any guarantees about the primitive rasterization order when using the new relaxed mode?

RESOLVED: No. In this case the rasterization order is completely implementation dependent, but in practice it is expected to partially still follow the order of incoming primitives.

4) Does the new relaxed rasterization order have any adverse effect on repeatability and other invariance rules of the API?

RESOLVED: Yes, in the sense that it extends the list of exceptions when the repeatability requirement does not apply.

#### Examples

None

#### Issues

None

#### Version History

- Revision 1, 2016-04-25 (Daniel Rakos)

  - Initial draft.

#### VK_AMD_shader_ballot

Name String

  `VK_AMD_shader_ballot`

Extension Type

  Device extension

Registered Extension Number

  38

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Dominik Witczak dominikwitczakamd

Last Modified Date

  2016-09-19

IP Status

  No known IP claims.

Contributors

  - Qun Lin, AMD

  - Graham Sellers, AMD

  - Daniel Rakos, AMD

  - Rex Xu, AMD

  - Dominik Witczak, AMD

  - Matthäus G. Chajdas, AMD

This extension adds support for the following SPIR-V extension in Vulkan:

- `SPV_AMD_shader_ballot`

| editing-note Shouldn’t the SPV extension be in the Interactions and External Dependencies block?

#### Version History

- Revision 1, 2016-09-19 (Dominik Witczak)

  - Initial draft

#### VK_AMD_shader_core_properties

Name String

  `VK_AMD_shader_core_properties`

Extension Type

  Device extension

Registered Extension Number

  186

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Martin Dinkov mdinkov

Last Modified Date

  2019-06-25

IP Status

  No known IP claims.

Contributors

  - Martin Dinkov, AMD

  - Matthaeus G. Chajdas, AMD

This extension exposes shader core properties for a target physical device through the `VK_KHR_get_physical_device_properties2` extension. Please refer to the example below for proper usage.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_CORE_PROPERTIES_AMD`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceShaderCorePropertiesAMD

#### New Functions

None.

#### Examples

This example retrieves the shader core properties for a physical device.

    extern VkInstance       instance;

    PFN_vkGetPhysicalDeviceProperties2 pfnVkGetPhysicalDeviceProperties2 =
        reinterpret_cast<PFN_vkGetPhysicalDeviceProperties2>
        (vkGetInstanceProcAddr(instance, "vkGetPhysicalDeviceProperties2") );

    VkPhysicalDeviceProperties2             general_props;
    VkPhysicalDeviceShaderCorePropertiesAMD shader_core_properties;

    shader_core_properties.pNext = nullptr;
    shader_core_properties.sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_CORE_PROPERTIES_AMD;

    general_props.pNext = &shader_core_properties;
    general_props.sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROPERTIES_2;

    // After this call, shader_core_properties has been populated
    pfnVkGetPhysicalDeviceProperties2(device, &general_props);

    printf("Number of shader engines: %d\n",
        m_shader_core_properties.shader_engine_count =
        shader_core_properties.shaderEngineCount;
    printf("Number of shader arrays: %d\n",
        m_shader_core_properties.shader_arrays_per_engine_count =
        shader_core_properties.shaderArraysPerEngineCount;
    printf("Number of CUs per shader array: %d\n",
        m_shader_core_properties.compute_units_per_shader_array =
        shader_core_properties.computeUnitsPerShaderArray;
    printf("Number of SIMDs per compute unit: %d\n",
        m_shader_core_properties.simd_per_compute_unit =
        shader_core_properties.simdPerComputeUnit;
    printf("Number of wavefront slots in each SIMD: %d\n",
        m_shader_core_properties.wavefronts_per_simd =
        shader_core_properties.wavefrontsPerSimd;
    printf("Number of threads per wavefront: %d\n",
        m_shader_core_properties.wavefront_size =
        shader_core_properties.wavefrontSize;
    printf("Number of physical SGPRs per SIMD: %d\n",
        m_shader_core_properties.sgprs_per_simd =
        shader_core_properties.sgprsPerSimd;
    printf("Minimum number of SGPRs that can be allocated by a wave: %d\n",
        m_shader_core_properties.min_sgpr_allocation =
        shader_core_properties.minSgprAllocation;
    printf("Number of available SGPRs: %d\n",
        m_shader_core_properties.max_sgpr_allocation =
        shader_core_properties.maxSgprAllocation;
    printf("SGPRs are allocated in groups of this size: %d\n",
        m_shader_core_properties.sgpr_allocation_granularity =
        shader_core_properties.sgprAllocationGranularity;
    printf("Number of physical VGPRs per SIMD: %d\n",
        m_shader_core_properties.vgprs_per_simd =
        shader_core_properties.vgprsPerSimd;
    printf("Minimum number of VGPRs that can be allocated by a wave: %d\n",
        m_shader_core_properties.min_vgpr_allocation =
        shader_core_properties.minVgprAllocation;
    printf("Number of available VGPRs: %d\n",
        m_shader_core_properties.max_vgpr_allocation =
        shader_core_properties.maxVgprAllocation;
    printf("VGPRs are allocated in groups of this size: %d\n",
        m_shader_core_properties.vgpr_allocation_granularity =
        shader_core_properties.vgprAllocationGranularity;

#### Version History

- Revision 2, 2019-06-25 (Matthaeus G. Chajdas)

  - Clarified the meaning of a few fields.

- Revision 1, 2018-02-15 (Martin Dinkov)

  - Initial draft.

#### VK_AMD_shader_core_properties2

Name String

  `VK_AMD_shader_core_properties2`

Extension Type

  Device extension

Registered Extension Number

  228

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_AMD_shader_core_properties`

Contact

  - Matthaeus G. Chajdas anteru

Last Modified Date

  2019-07-26

IP Status

  No known IP claims.

Contributors

  - Matthaeus G. Chajdas, AMD

  - Tobias Hector, AMD

This extension exposes additional shader core properties for a target physical device through the `VK_KHR_get_physical_device_properties2` extension.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_CORE_PROPERTIES_2_AMD`

#### New Enums

- VkShaderCorePropertiesFlagBitsAMD

#### New Structures

- VkPhysicalDeviceShaderCoreProperties2AMD

#### New Functions

None.

#### Examples

None.

#### Version History

- Revision 1, 2019-07-26 (Matthaeus G. Chajdas)

  - Initial draft.

#### VK_AMD_shader_explicit_vertex_parameter

Name String

  `VK_AMD_shader_explicit_vertex_parameter`

Extension Type

  Device extension

Registered Extension Number

  22

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Qun Lin linqun

Last Modified Date

  2016-05-10

IP Status

  No known IP claims.

Contributors

  - Matthaeus G. Chajdas, AMD

  - Qun Lin, AMD

  - Daniel Rakos, AMD

  - Graham Sellers, AMD

  - Rex Xu, AMD

This extension adds support for the following SPIR-V extension in Vulkan:

- `SPV_AMD_shader_explicit_vertex_parameter`

| editing-note Shouldn’t the SPV extension be in the Interactions and External Dependencies block?

#### Version History

- Revision 1, 2016-05-10 (Daniel Rakos)

  - Initial draft

#### VK_AMD_shader_fragment_mask

Name String

  `VK_AMD_shader_fragment_mask`

Extension Type

  Device extension

Registered Extension Number

  138

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Aaron Hagan AaronHaganAMD

Last Modified Date

  2017-08-16

IP Status

  No known IP claims.

Dependencies

  - Requires the `SPV_AMD_shader_fragment_mask` SPIR-V extension.

Contributors

  - Aaron Hagan, AMD

  - Daniel Rakos, AMD

  - Timothy Lottes, AMD

This extension provides efficient read access to the fragment mask in compressed multisampled color surfaces. The fragment mask is a lookup table that associates color samples with color fragment values.

From a shader, the fragment mask can be fetched with a call to `fragmentMaskFetchAMD`, which returns a single `uint` where each subsequent four bits specify the color fragment index corresponding to the color sample, starting from the least significant bit. For example, when eight color samples are used, the color fragment index for color sample 0 will be in bits 0-3 of the fragment mask, for color sample 7 the index will be in bits 28-31.

The color fragment for a particular color sample may then be fetched with the corresponding fragment mask value using the `fragmentFetchAMD` shader function.

#### New Object Types

None.

#### New Enum Constants

None.

#### New Enums

None.

#### New SPIR-V Capabilities

- `FragmentMaskAMD`

#### New Structures

None.

#### New Functions

None.

#### Examples

This example shows a shader that queries the fragment mask from a multisampled compressed surface and uses it to query fragment values.

    #version 450 core

    #extension GL_AMD_shader_fragment_mask: enable

    layout(binding = 0) uniform sampler2DMS       s2DMS;
    layout(binding = 1) uniform isampler2DMSArray is2DMSArray;

    layout(binding = 2, input_attachment_index = 0) uniform usubpassInputMS usubpassMS;

    layout(location = 0) out vec4 fragColor;

    void main()
    {
        vec4 fragOne = vec4(0.0);

        uint fragMask = fragmentMaskFetchAMD(s2DMS, ivec2(2, 3));
        uint fragIndex = (fragMask & 0xF0) >> 4;
        fragOne += fragmentFetchAMD(s2DMS, ivec2(2, 3), 1);

        fragMask = fragmentMaskFetchAMD(is2DMSArray, ivec3(2, 3, 1));
        fragIndex = (fragMask & 0xF0) >> 4;
        fragOne += fragmentFetchAMD(is2DMSArray, ivec3(2, 3, 1), fragIndex);

        fragMask = fragmentMaskFetchAMD(usubpassMS);
        fragIndex = (fragMask & 0xF0) >> 4;
        fragOne += fragmentFetchAMD(usubpassMS, fragIndex);

        fragColor = fragOne;
    }

#### Version History

- Revision 1, 2017-08-16 (Aaron Hagan)

  - Initial draft

#### VK_AMD_shader_image_load_store_lod

Name String

  `VK_AMD_shader_image_load_store_lod`

Extension Type

  Device extension

Registered Extension Number

  47

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Dominik Witczak dominikwitczakamd

Last Modified Date

  2017-08-21

Interactions and External Dependencies

  - This extension requires the `SPV_AMD_shader_image_load_store_lod` SPIR-V extension.

  - This extension requires `GL_AMD_shader_image_load_store_lod` for GLSL-based source languages.

IP Status

  No known IP claims.

Contributors

  - Dominik Witczak, AMD

  - Qun Lin, AMD

  - Rex Xu, AMD

This extension adds support for the following SPIR-V extension in Vulkan:

- `SPV_AMD_shader_image_load_store_lod`

#### Version History

- Revision 1, 2017-08-21 (Dominik Witczak)

  - Initial draft

#### VK_AMD_shader_info

Name String

  `VK_AMD_shader_info`

Extension Type

  Device extension

Registered Extension Number

  43

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Jaakko Konttinen jaakkoamd

Last Modified Date

  2017-10-09

IP Status

  No known IP claims.

Contributors

  - Jaakko Konttinen, AMD

This extension adds a way to query certain information about a compiled shader which is part of a pipeline. This information may include shader disassembly, shader binary and various statistics about a shader’s resource usage.

While this extension provides a mechanism for extracting this information, the details regarding the contents or format of this information are not specified by this extension and may be provided by the vendor externally.

Furthermore, all information types are optionally supported, and users should not assume every implementation supports querying every type of information.

#### New Object Types

None.

#### New Enum Constants

None.

#### New Enums

- VkShaderInfoTypeAMD

#### New Structures

- VkShaderResourceUsageAMD

- VkShaderStatisticsInfoAMD

#### New Functions

- vkGetShaderInfoAMD

#### Examples

This example extracts the register usage of a fragment shader within a particular graphics pipeline:

    extern VkDevice device;
    extern VkPipeline gfxPipeline;

    PFN_vkGetShaderInfoAMD pfnGetShaderInfoAMD = (PFN_vkGetShaderInfoAMD)vkGetDeviceProcAddr(
        device, "vkGetShaderInfoAMD");

    VkShaderStatisticsInfoAMD statistics = {};

    size_t dataSize = sizeof(statistics);

    if (pfnGetShaderInfoAMD(device,
        gfxPipeline,
        VK_SHADER_STAGE_FRAGMENT_BIT,
        VK_SHADER_INFO_TYPE_STATISTICS_AMD,
        &dataSize,
        &statistics) == VK_SUCCESS)
    {
        printf("VGPR usage: %d\n", statistics.resourceUsage.numUsedVgprs);
        printf("SGPR usage: %d\n", statistics.resourceUsage.numUsedSgprs);
    }

The following example continues the previous example by subsequently attempting to query and print shader disassembly about the fragment shader:

    // Query disassembly size (if available)
    if (pfnGetShaderInfoAMD(device,
        gfxPipeline,
        VK_SHADER_STAGE_FRAGMENT_BIT,
        VK_SHADER_INFO_TYPE_DISASSEMBLY_AMD,
        &dataSize,
        nullptr) == VK_SUCCESS)
    {
        printf("Fragment shader disassembly:\n");

        void* disassembly = malloc(dataSize);

        // Query disassembly and print
        if (pfnGetShaderInfoAMD(device,
            gfxPipeline,
            VK_SHADER_STAGE_FRAGMENT_BIT,
            VK_SHADER_INFO_TYPE_DISASSEMBLY_AMD,
            &dataSize,
            disassembly) == VK_SUCCESS)
        {
            printf((char*)disassembly);
        }

        free(disassembly);
    }

#### Version History

- Revision 1, 2017-10-09 (Jaakko Konttinen)

  - Initial revision

#### VK_AMD_shader_trinary_minmax

Name String

  `VK_AMD_shader_trinary_minmax`

Extension Type

  Device extension

Registered Extension Number

  21

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Qun Lin linqun

Last Modified Date

  2016-05-10

IP Status

  No known IP claims.

Contributors

  - Matthaeus G. Chajdas, AMD

  - Qun Lin, AMD

  - Daniel Rakos, AMD

  - Graham Sellers, AMD

  - Rex Xu, AMD

This extension adds support for the following SPIR-V extension in Vulkan:

- `SPV_AMD_shader_trinary_minmax`

| editing-note Shouldn’t the SPV extension be in the Interactions and External Dependencies block?

#### Version History

- Revision 1, 2016-05-10 (Daniel Rakos)

  - Initial draft

#### VK_AMD_texture_gather_bias_lod

Name String

  `VK_AMD_texture_gather_bias_lod`

Extension Type

  Device extension

Registered Extension Number

  42

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Rex Xu amdrexu

Last Modified Date

  2017-03-21

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Requires the `SPV_AMD_texture_gather_bias_lod` SPIR-V extension.

Contributors

  - Dominik Witczak, AMD

  - Daniel Rakos, AMD

  - Graham Sellers, AMD

  - Matthaeus G. Chajdas, AMD

  - Qun Lin, AMD

  - Rex Xu, AMD

  - Timothy Lottes, AMD

This extension adds two related features.

Firstly, support for the following SPIR-V extension in Vulkan is added:

- `SPV_AMD_texture_gather_bias_lod`

Secondly, the extension allows the application to query which formats can be used together with the new function prototypes introduced by the SPIR-V extension.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_TEXTURE_LOD_GATHER_FORMAT_PROPERTIES_AMD`

#### New Enums

None.

#### New SPIR-V Capabilities

- `ImageGatherBiasLodAMD`

#### New Structures

- VkTextureLODGatherFormatPropertiesAMD

#### New Functions

None.

#### Examples

    struct VkTextureLODGatherFormatPropertiesAMD
    {
        VkStructureType sType;
        const void*     pNext;
        VkBool32        supportsTextureGatherLODBiasAMD;
    };

    // ----------------------------------------------------------------------------------------
    // How to detect if an image format can be used with the new function prototypes.
    VkPhysicalDeviceImageFormatInfo2   formatInfo;
    VkImageFormatProperties2           formatProps;
    VkTextureLODGatherFormatPropertiesAMD textureLODGatherSupport;

    textureLODGatherSupport.sType = VK_STRUCTURE_TYPE_TEXTURE_LOD_GATHER_FORMAT_PROPERTIES_AMD;
    textureLODGatherSupport.pNext = nullptr;

    formatInfo.sType  = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGE_FORMAT_INFO_2;
    formatInfo.pNext  = nullptr;
    formatInfo.format = ...;
    formatInfo.type   = ...;
    formatInfo.tiling = ...;
    formatInfo.usage  = ...;
    formatInfo.flags  = ...;

    formatProps.sType = VK_STRUCTURE_TYPE_IMAGE_FORMAT_PROPERTIES_2;
    formatProps.pNext = &textureLODGatherSupport;

    vkGetPhysicalDeviceImageFormatProperties2(physical_device, &formatInfo, &formatProps);

    if (textureLODGatherSupport.supportsTextureGatherLODBiasAMD == VK_TRUE)
    {
        // physical device supports SPV_AMD_texture_gather_bias_lod for the specified
        // format configuration.
    }
    else
    {
        // physical device does not support SPV_AMD_texture_gather_bias_lod for the
        // specified format configuration.
    }

#### Version History

- Revision 1, 2017-03-21 (Dominik Witczak)

  - Initial draft

#### VK_ANDROID_external_memory_android_hardware_buffer

Name String

  `VK_ANDROID_external_memory_android_hardware_buffer`

Extension Type

  Device extension

Registered Extension Number

  130

Revision

  3

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_sampler_ycbcr_conversion`

  - Requires `VK_KHR_external_memory`

  - Requires `VK_EXT_queue_family_foreign`

Contact

  - Jesse Hall critsec

Last Modified Date

  2019-08-27

IP Status

  No known IP claims.

Contributors

  - Ray Smith, ARM

  - Chad Versace, Google

  - Jesse Hall, Google

  - Tobias Hector, Imagination

  - James Jones, NVIDIA

  - Tony Zlatinski, NVIDIA

  - Matthew Netsch, Qualcomm

  - Andrew Garrard, Samsung

This extension enables an application to import Android AHardwareBuffer objects created outside of the Vulkan device into Vulkan memory objects, where they can be bound to images and buffers. It also allows exporting an AHardwareBuffer from a Vulkan memory object for symmetry with other operating systems. But since not all AHardwareBuffer usages and formats have Vulkan equivalents, exporting from Vulkan provides strictly less functionality than creating the AHardwareBuffer externally and importing it.

Some AHardwareBuffer images have implementation-defined external formats that may not correspond to Vulkan formats. Sampler Y′CBCR conversion can be used to sample from these images and convert them to a known color space.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_ANDROID_HARDWARE_BUFFER_USAGE_ANDROID`

  - `VK_STRUCTURE_TYPE_ANDROID_HARDWARE_BUFFER_PROPERTIES_ANDROID`

  - `VK_STRUCTURE_TYPE_ANDROID_HARDWARE_BUFFER_FORMAT_PROPERTIES_ANDROID`

  - `VK_STRUCTURE_TYPE_IMPORT_ANDROID_HARDWARE_BUFFER_INFO_ANDROID`

  - `VK_STRUCTURE_TYPE_MEMORY_GET_ANDROID_HARDWARE_BUFFER_INFO_ANDROID`

  - `VK_STRUCTURE_TYPE_EXTERNAL_FORMAT_ANDROID`

- Extending VkExternalMemoryHandleTypeFlagBits:

  - `VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID`

#### New Enums

None.

#### New Structs

- VkAndroidHardwareBufferUsageANDROID

- VkAndroidHardwareBufferPropertiesANDROID

- VkAndroidHardwareBufferFormatPropertiesANDROID

- VkImportAndroidHardwareBufferInfoANDROID

- VkMemoryGetAndroidHardwareBufferInfoANDROID

- VkExternalFormatANDROID

#### New Functions

- vkGetAndroidHardwareBufferPropertiesANDROID

- vkGetMemoryAndroidHardwareBufferANDROID

#### Issues

1) Other external memory objects are represented as weakly-typed handles (e.g. Win32 `HANDLE` or POSIX file descriptor), and require a handle type parameter along with handles. AHardwareBuffer is strongly typed, so naming the handle type is redundant. Does symmetry justify adding handle type parameters/fields anyway?

RESOLVED: No. The handle type is already provided in places that treat external memory objects generically. In the places we would add it, the application code that would have to provide the handle type value is already dealing with AHardwareBuffer-specific commands/structures; the extra symmetry would not be enough to make that code generic.

2) The internal layout and therefore size of a AHardwareBuffer image may depend on native usage flags that do not have corresponding Vulkan counterparts. Do we provide this info to vkCreateImage somehow, or allow the allocation size reported by vkGetImageMemoryRequirements to be approximate?

RESOLVED: Allow the allocation size to be unspecified when allocating the memory. It has to work this way for exported image memory anyway, since AHardwareBuffer allocation happens in vkAllocateMemory, and internally is performed by a separate HAL, not the Vulkan implementation itself. There is a similar issue with vkGetImageSubresourceLayout: the layout is determined by the allocator HAL, so it is not known until the image is bound to memory.

3) Should the result of sampling an external-format image with the suggested Y′CBCR conversion parameters yield the same results as using a `samplerExternalOES` in OpenGL ES?

RESOLVED: This would be desirable, so that apps converting from OpenGL ES to Vulkan could get the same output given the same input. But since sampling and conversion from Y′CBCR images is so loosely defined in OpenGL ES, multiple implementations do it in a way that doesn’t conform to Vulkan’s requirements. Modifying the OpenGL ES implementation would be difficult, and would change the output of existing unmodified applications. Changing the output only for applications that are being modified gives developers the chance to notice and mitigate any problems. Implementations are encouraged to minimize differences as much as possible without causing compatibility problems for existing OpenGL ES applications or violating Vulkan requirements.

4) Should an AHardwareBuffer with `AHARDWAREBUFFER_USAGE_CPU_`* usage be mappable in Vulkan? Should it be possible to export an `AHardwareBuffers` with such usage?

RESOLVED: Optional, and mapping in Vulkan is not the same as `AHardwareBuffer_lock`. The semantics of these are different: mapping in memory is persistent, just gives a raw view of the memory contents, and does not involve ownership. `AHardwareBuffer_lock` gives the host exclusive access to the buffer, is temporary, and allows for reformatting copy-in/copy-out. Implementations are not required to support host-visible memory types for imported Android hardware buffers or resources backed by them. If a host-visible memory type is supported and used, the memory can be mapped in Vulkan, but doing so follows Vulkan semantics: it is just a raw view of the data and does not imply ownership (this means implementations must not internally call `AHardwareBuffer_lock` to implement vkMapMemory, or assume the application has done so). Implementations are not required to support linear-tiled images backed by Android hardware buffers, even if the AHardwareBuffer has CPU usage. There is no reliable way to allocate memory in Vulkan that can be exported to a AHardwareBuffer with CPU usage.

5) Android may add new AHardwareBuffer formats and usage flags over time. Can reference to them be added to this extension, or do they need a new extension?

RESOLVED: This extension can document the interaction between the new AHB formats/usages and existing Vulkan features. No new Vulkan features or implementation requirements can be added. The extension version number will be incremented when this additional documentation is added, but the version number does not indicate that an implementaiton supports Vulkan memory or resources that map to the new AHardwareBuffer features: support for that must be queried with vkGetPhysicalDeviceImageFormatProperties2 or is implied by successfully allocating a AHardwareBuffer outside of Vulkan that uses the new feature and has a GPU usage flag.

In essence, these are new features added to a new Android API level, rather than new Vulkan features. The extension will only document how existing Vulkan features map to that new Android feature.

#### Version History

- Revision 3, 2019-08-27 (Jon Leech)

  - Update revision history to correspond to XML version number

- Revision 2, 2018-04-09 (Petr Kraus)

  - Markup fixes and remove incorrect Draft status

- Revision 1, 2018-03-04 (Jesse Hall)

  - Initial version

#### VK_FUCHSIA_imagepipe_surface

Name String

  `VK_FUCHSIA_imagepipe_surface`

Extension Type

  Instance extension

Registered Extension Number

  215

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_surface`

Contact

  - Craig Stout cdotstout

Last Modified Date

  2018-07-27

IP Status

  No known IP claims.

Contributors

  - Craig Stout, Google

  - Ian Elliott, Google

  - Jesse Hall, Google

The `VK_FUCHSIA_imagepipe_surface` extension is an instance extension. It provides a mechanism to create a VkSurfaceKHR object (defined by the `VK_KHR_surface` extension) that refers to a Fuchsia `imagePipeHandle`.

#### New Object Types

None

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_IMAGEPIPE_SURFACE_CREATE_INFO_FUCHSIA`

#### New Enums

None

#### New Structures

- VkImagePipeSurfaceCreateInfoFUCHSIA

#### New Functions

- vkCreateImagePipeSurfaceFUCHSIA

#### Issues

None

#### Version History

- Revision 1, 2018-07-27 (Craig Stout)

  - Initial draft.

#### VK_GGP_frame_token

Name String

  `VK_GGP_frame_token`

Extension Type

  Device extension

Registered Extension Number

  192

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_swapchain`

  - Requires `VK_GGP_stream_descriptor_surface`

Contact

  - Jean-Francois Roy jfroy

Last Modified Date

  2019-01-28

IP Status

  No known IP claims.

Contributors

  - Jean-Francois Roy, Google

  - Richard O’Grady, Google

This extension allows an application that uses the `VK_KHR_swapchain` extension in combination with a Google Games Platform surface provided by the `VK_GGP_stream_descriptor_surface` extension to associate a Google Games Platform frame token with a present operation.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PRESENT_FRAME_TOKEN_GGP`

#### New Enums

None.

#### New Structures

- VkPresentFrameTokenGGP

#### New Functions

None.

#### Issues

None.

#### Version History

- Revision 1, 2018-11-26 (Jean-Francois Roy)

  - Initial revision.

#### VK_GGP_stream_descriptor_surface

Name String

  `VK_GGP_stream_descriptor_surface`

Extension Type

  Instance extension

Registered Extension Number

  50

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_surface`

Contact

  - Jean-Francois Roy jfroy

Last Modified Date

  2019-01-28

IP Status

  No known IP claims.

Contributors

  - Jean-Francois Roy, Google

  - Brad Grantham, Google

  - Connor Smith, Google

  - Cort Stratton, Google

  - Hai Nguyen, Google

  - Ian Elliott, Google

  - Jesse Hall, Google

  - Jim Ray, Google

  - Katherine Wu, Google

  - Kaye Mason, Google

  - Kuangye Guo, Google

  - Mark Segal, Google

  - Nicholas Vining, Google

  - Paul Lalonde, Google

  - Richard O’Grady, Google

The `VK_GGP_stream_descriptor_surface` extension is an instance extension. It provides a mechanism to create a VkSurfaceKHR object (defined by the `VK_KHR_surface` extension) that refers to a Google Games Platform `GgpStreamDescriptor`.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_STREAM_DESCRIPTOR_SURFACE_CREATE_INFO_GGP`

#### New Enums

None.

#### New Structures

- VkStreamDescriptorSurfaceCreateInfoGGP

#### New Functions

- vkCreateStreamDescriptorSurfaceGGP

#### Issues

None.

#### Version History

- Revision 1, 2018-11-26 (Jean-Francois Roy)

  - Initial revision.

#### VK_GOOGLE_decorate_string

Name String

  `VK_GOOGLE_decorate_string`

Extension Type

  Device extension

Registered Extension Number

  225

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Hai Nguyen chaoticbob

Last Modified Date

  2018-07-09

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Requires the `SPV_GOOGLE_decorate_string` SPIR-V extension.

Contributors

  - Hai Nguyen, Google

  - Neil Henning, AMD

The `VK_GOOGLE_decorate_string` extension allows use of the `SPV_GOOGLE_decorate_string` extension in SPIR-V shader modules.

#### New Enum Constants

None.

#### New Structures

None.

#### New SPIR-V Capabilities

None.

#### Issues

#### Version History

- Revision 1, 2018-07-09 (Neil Henning)

  - Initial draft

#### VK_GOOGLE_display_timing

Name String

  `VK_GOOGLE_display_timing`

Extension Type

  Device extension

Registered Extension Number

  93

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_swapchain`

Contact

  - Ian Elliott ianelliottus

Last Modified Date

  2017-02-14

IP Status

  No known IP claims.

Contributors

  - Ian Elliott, Google

  - Jesse Hall, Google

This device extension allows an application that uses the `VK_KHR_swapchain` extension to obtain information about the presentation engine’s display, to obtain timing information about each present, and to schedule a present to happen no earlier than a desired time. An application can use this to minimize various visual anomalies (e.g. stuttering).

Traditional game and real-time animation applications need to correctly position their geometry for when the presentable image will be presented to the user. To accomplish this, applications need various timing information about the presentation engine’s display. They need to know when presentable images were actually presented, and when they could have been presented. Applications also need to tell the presentation engine to display an image no sooner than a given time. This allows the application to avoid stuttering, so the animation looks smooth to the user.

This extension treats variable-refresh-rate (VRR) displays as if they are fixed-refresh-rate (FRR) displays.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PRESENT_TIMES_INFO_GOOGLE`

#### New Enums

None.

#### New Structures

- VkRefreshCycleDurationGOOGLE

- VkPastPresentationTimingGOOGLE

- VkPresentTimesInfoGOOGLE

- VkPresentTimeGOOGLE

#### New Functions

- vkGetRefreshCycleDurationGOOGLE

- vkGetPastPresentationTimingGOOGLE

#### Issues

None.

#### Examples

| Note The example code for the this extension (like the `VK_KHR_surface` and `VK_GOOGLE_display_timing` extensions) is contained in the cube demo that is shipped with the official Khronos SDK, and is being kept up-to-date in that location (see: https://github.com/KhronosGroup/Vulkan-Tools/blob/master/cube/cube.c ).

#### Version History

- Revision 1, 2017-02-14 (Ian Elliott)

  - Internal revisions

#### VK_GOOGLE_hlsl_functionality1

Name String

  `VK_GOOGLE_hlsl_functionality1`

Extension Type

  Device extension

Registered Extension Number

  224

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Hai Nguyen chaoticbob

Last Modified Date

  2018-07-09

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Requires the `SPV_GOOGLE_hlsl_functionality1` SPIR-V extension.

Contributors

  - Hai Nguyen, Google

  - Neil Henning, AMD

The `VK_GOOGLE_hlsl_functionality1` extension allows use of the `SPV_GOOGLE_hlsl_functionality1` extension in SPIR-V shader modules.

#### New Enum Constants

None.

#### New Structures

None.

#### New SPIR-V Capabilities

None.

#### Issues

#### Version History

- Revision 1, 2018-07-09 (Neil Henning)

  - Initial draft

#### VK_GOOGLE_user_type

Name String

  `VK_GOOGLE_user_type`

Extension Type

  Device extension

Registered Extension Number

  290

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Kaye Mason chaleur

Last Modified Date

  2019-07-09

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Requires the `SPV_GOOGLE_user_type` SPIR-V extension.

Contributors

  - Kaye Mason, Google

  - Hai Nguyen, Google

The `VK_GOOGLE_user_type` extension allows use of the `SPV_GOOGLE_user_type` extension in SPIR-V shader modules.

#### New Enum Constants

None.

#### New Structures

None.

#### New SPIR-V Capabilities

None.

#### Issues

#### Version History

- Revision 1, 2019-09-07 (Kaye Mason)

  - Initial draft

#### VK_IMG_filter_cubic

Name String

  `VK_IMG_filter_cubic`

Extension Type

  Device extension

Registered Extension Number

  16

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Tobias Hector tobski

Last Modified Date

  2016-02-23

Contributors

  - Tobias Hector, Imagination Technologies

`VK_IMG_filter_cubic` adds an additional, high quality cubic filtering mode to Vulkan, using a Catmull-Rom bicubic filter. Performing this kind of filtering can be done in a shader by using 16 samples and a number of instructions, but this can be inefficient. The cubic filter mode exposes an optimized high quality texture sampling using fixed texture sampling functionality.

#### New Enum Constants

- Extending VkFilter:

  - `VK_FILTER_CUBIC_IMG`

- Extending VkFormatFeatureFlagBits

  - `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_IMG`

#### Example

Creating a sampler with the new filter for both magnification and minification

        VkSamplerCreateInfo createInfo =
        {
            VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO // sType
            // Other members set to application-desired values
        };

        createInfo.magFilter = VK_FILTER_CUBIC_IMG;
        createInfo.minFilter = VK_FILTER_CUBIC_IMG;

        VkSampler sampler;
        VkResult result = vkCreateSampler(
            device,
            &createInfo,
            &sampler);

#### Version History

- Revision 1, 2016-02-23 (Tobias Hector)

  - Initial version

#### VK_IMG_format_pvrtc

Name String

  `VK_IMG_format_pvrtc`

Extension Type

  Device extension

Registered Extension Number

  55

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Stuart Smith

Last Modified Date

  2019-09-02

IP Status

  Imagination Technologies Proprietary

Contributors

  - Stuart Smith, Imagination Technologies

`VK_IMG_format_pvrtc` provides additional texture compression functionality specific to Imagination Technologies PowerVR Texture compression format (called PVRTC).

#### New Object Types

None.

#### New Enum Constants

- Extending VkFormat:

  - `VK_FORMAT_PVRTC1_2BPP_UNORM_BLOCK_IMG`

  - `VK_FORMAT_PVRTC1_4BPP_UNORM_BLOCK_IMG`

  - `VK_FORMAT_PVRTC2_2BPP_UNORM_BLOCK_IMG`

  - `VK_FORMAT_PVRTC2_4BPP_UNORM_BLOCK_IMG`

  - `VK_FORMAT_PVRTC1_2BPP_SRGB_BLOCK_IMG`

  - `VK_FORMAT_PVRTC1_4BPP_SRGB_BLOCK_IMG`

  - `VK_FORMAT_PVRTC2_2BPP_SRGB_BLOCK_IMG`

  - `VK_FORMAT_PVRTC2_4BPP_SRGB_BLOCK_IMG`

#### New Enum Constants

None.

#### New Structures

None.

#### New Functions

None.

#### Issues

None.

#### Version History

- Revision 1, 2019-09-02 (Stuart Smith)

  - Initial version

#### VK_INTEL_performance_query

Name String

  `VK_INTEL_performance_query`

Extension Type

  Device extension

Registered Extension Number

  211

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Lionel Landwerlin llandwerlin

Last Modified Date

  2018-05-16

IP Status

  No known IP claims.

Contributors

  - Lionel Landwerlin, Intel

  - Piotr Maciejewski, Intel

This extension allows an application to capture performance data to be interpreted by a external application or library.

Such a library is available at : https://github.com/intel/metrics-discovery

Performance analysis tools such as GPA (https://software.intel.com/en-us/gpa) make use of this extension and the metrics-discovery library to present the data in a human readable way.

#### New Object Types

- VkPerformanceConfigurationINTEL

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_QUERY_POOL_CREATE_INFO_INTEL`

  - `VK_STRUCTURE_TYPE_INITIALIZE_PERFORMANCE_API_INFO_INTEL`

  - `VK_STRUCTURE_TYPE_PERFORMANCE_MARKER_INFO_INTEL`

  - `VK_STRUCTURE_TYPE_PERFORMANCE_STREAM_MARKER_INFO_INTEL`

  - `VK_STRUCTURE_TYPE_PERFORMANCE_OVERRIDE_INFO_INTEL`

  - `VK_STRUCTURE_TYPE_PERFORMANCE_CONFIGURATION_ACQUIRE_INFO_INTEL`

- Extending VkQueryType:

  - `VK_QUERY_TYPE_PERFORMANCE_QUERY_INTEL`

#### New Enums

- VkPerformanceConfigurationTypeINTEL

- VkQueryPoolSamplingModeINTEL

- VkPerformanceOverrideTypeINTEL

- VkPerformanceParameterTypeINTEL

- VkPerformanceValueTypeINTEL

#### New Structures

- VkPerformanceValueINTEL

- VkInitializePerformanceApiInfoINTEL

- VkQueryPoolPerformanceQueryCreateInfoINTEL

- VkPerformanceMarkerInfoINTEL

- VkPerformanceStreamMarkerInfoINTEL

- VkPerformanceOverrideInfoINTEL

- VkPerformanceConfigurationAcquireInfoINTEL

#### New Functions

- vkInitializePerformanceApiINTEL

- vkUninitializePerformanceApiINTEL

- vkCmdSetPerformanceMarkerINTEL

- vkCmdSetPerformanceOverrideINTEL

- vkCmdSetPerformanceStreamMarkerINTEL

- vkAcquirePerformanceConfigurationINTEL

- vkReleasePerformanceConfigurationINTEL

- vkQueueSetPerformanceConfigurationINTEL

- vkGetPerformanceParameterINTEL

#### Issues

None.

#### Example Code

    // A previously created device
    VkDevice device;

    // A queue derived from the device
    VkQueue queue;

    VkInitializePerformanceApiInfoINTEL performanceApiInfoIntel = {
      VK_STRUCTURE_TYPE_INITIALIZE_PERFORMANCE_API_INFO_INTEL,
      NULL,
      NULL
    };

    vkInitializePerformanceApiINTEL(
      device,
      &performanceApiInfoIntel);

    VkQueryPoolPerformanceQueryCreateInfoINTEL queryPoolIntel = {
      VK_STRUCTURE_TYPE_QUERY_POOL_CREATE_INFO_INTEL,
      NULL,
      VK_QUERY_POOL_SAMPLING_MODE_MANUAL_INTEL,
    };

    VkQueryPoolCreateInfo queryPoolCreateInfo = {
      VK_STRUCTURE_TYPE_QUERY_POOL_CREATE_INFO,
      &queryPoolIntel,
      0,
      VK_QUERY_TYPE_PERFORMANCE_QUERY_INTEL,
      1,
      0
    };

    VkQueryPool queryPool;

    VkResult result = vkCreateQueryPool(
      device,
      &queryPoolCreateInfo,
      NULL,
      &queryPool);

    assert(VK_SUCCESS == result);

    // A command buffer we want to record counters on
    VkCommandBuffer commandBuffer;

    VkCommandBufferBeginInfo commandBufferBeginInfo = {
      VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO,
      NULL,
      VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT,
      NULL
    };

    result = vkBeginCommandBuffer(commandBuffer, &commandBufferBeginInfo);

    assert(VK_SUCCESS == result);

    vkCmdResetQueryPool(
      commandBuffer,
      queryPool,
      0,
      1);

    vkCmdBeginQuery(
      commandBuffer,
      queryPool,
      0,
      0);

    // Perform the commands you want to get performance information on
    // ...

    // Perform a barrier to ensure all previous commands were complete before
    // ending the query
    vkCmdPipelineBarrier(commandBuffer,
      VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT,
      VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT,
      0,
      0,
      NULL,
      0,
      NULL,
      0,
      NULL);

    vkCmdEndQuery(
      commandBuffer,
      queryPool,
      0);

    result = vkEndCommandBuffer(commandBuffer);

    assert(VK_SUCCESS == result);

    VkPerformanceConfigurationAcquireInfoINTEL performanceConfigurationAcquireInfo = {
      VK_STRUCTURE_TYPE_PERFORMANCE_CONFIGURATION_ACQUIRE_INFO_INTEL,
      NULL,
      VK_PERFORMANCE_CONFIGURATION_TYPE_COMMAND_QUEUE_METRICS_DISCOVERY_ACTIVATED_INTEL
    };

    VkPerformanceConfigurationINTEL performanceConfigurationIntel;

    result = vkAcquirePerformanceConfigurationINTEL(
      device,
      &performanceConfigurationAcquireInfo,
      &performanceConfigurationIntel);

    vkQueueSetPerformanceConfigurationINTEL(queue, performanceConfigurationIntel);

    assert(VK_SUCCESS == result);

    // Submit the command buffer and wait for its completion
    // ...

    result = vkReleasePerformanceConfigurationINTEL(
      device,
      performanceConfigurationIntel);

    assert(VK_SUCCESS == result);

    // Get the report size from metrics-discovery's QueryReportSize

    result = vkGetQueryPoolResults(
      device,
      queryPool,
      0, 1, QueryReportSize,
      data, QueryReportSize, 0);

    assert(VK_SUCCESS == result);

    // The data can then be passed back to metrics-discovery from which
    // human readable values can be queried.

#### Version History

- Revision 2, 2020-03-06 (Lionel Landwerlin)

  - Rename VkQueryPoolCreateInfoINTEL in VkQueryPoolPerformanceQueryCreateInfoINTEL

- Revision 1, 2018-05-16 (Lionel Landwerlin)

  - Initial revision

#### VK_INTEL_shader_integer_functions2

Name String

  `VK_INTEL_shader_integer_functions2`

Extension Type

  Device extension

Registered Extension Number

  210

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Ian Romanick ianromanick

Last Modified Date

  2019-04-30

IP Status

  No known IP claims.

Contributors

  - Ian Romanick, Intel

  - Ben Ashbaugh, Intel

This extension adds support for several new integer instructions in SPIR-V for use in graphics shaders. Many of these instructions have pre-existing counterparts in the Kernel environment.

The added integer functions are defined by the `SPV_INTEL_shader_integer_functions` SPIR-V extension and can be used with the GL_INTEL_shader_integer_functions2 GLSL extension.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_INTEGER_FUNCTIONS_2_FEATURES_INTEL`

#### New Enums

None.

#### New Structures

- Extending VkPhysicalDeviceFeatures2:

  - VkPhysicalDeviceShaderIntegerFunctions2FeaturesINTEL

#### New Functions

None.

#### New SPIR-V Capabilities

- ShaderIntegerFunctions2INTEL

#### Issues

None.

#### Version History

- Revision 1, 2019-04-30 (Ian Romanick)

  - Initial draft

#### VK_MVK_ios_surface

Name String

  `VK_MVK_ios_surface`

Extension Type

  Instance extension

Registered Extension Number

  123

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_surface`

Contact

  - Bill Hollings billhollings

Last Modified Date

  2017-02-24

IP Status

  No known IP claims.

Contributors

  - Bill Hollings, The Brenwill Workshop Ltd.

The `VK_MVK_ios_surface` extension is an instance extension. It provides a mechanism to create a VkSurfaceKHR object (defined by the `VK_KHR_surface` extension) that refers to a `UIView`, the native surface type of iOS, which is underpinned by a CAMetalLayer, to support rendering to the surface using Apple’s Metal framework.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_IOS_SURFACE_CREATE_INFO_MVK`

#### New Enums

None.

#### New Structures

- VkIOSSurfaceCreateInfoMVK

#### New Functions

- vkCreateIOSSurfaceMVK

#### Issues

None.

#### Version History

- Revision 1, 2017-02-15 (Bill Hollings)

  - Initial draft.

- Revision 2, 2017-02-24 (Bill Hollings)

  - Minor syntax fix to emphasize firm requirement for UIView to be backed by a CAMetalLayer.

#### VK_MVK_macos_surface

Name String

  `VK_MVK_macos_surface`

Extension Type

  Instance extension

Registered Extension Number

  124

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_surface`

Contact

  - Bill Hollings billhollings

Last Modified Date

  2017-02-24

IP Status

  No known IP claims.

Contributors

  - Bill Hollings, The Brenwill Workshop Ltd.

The `VK_MVK_macos_surface` extension is an instance extension. It provides a mechanism to create a VkSurfaceKHR object (defined by the `VK_KHR_surface` extension) that refers to an `NSView`, the native surface type of macOS, which is underpinned by a CAMetalLayer, to support rendering to the surface using Apple’s Metal framework.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_MACOS_SURFACE_CREATE_INFO_MVK`

#### New Enums

None.

#### New Structures

- VkMacOSSurfaceCreateInfoMVK

#### New Functions

- vkCreateMacOSSurfaceMVK

#### Issues

None.

#### Version History

- Revision 1, 2017-02-15 (Bill Hollings)

  - Initial draft.

- Revision 2, 2017-02-24 (Bill Hollings)

  - Minor syntax fix to emphasize firm requirement for NSView to be backed by a CAMetalLayer.

#### VK_NN_vi_surface

Name String

  `VK_NN_vi_surface`

Extension Type

  Instance extension

Registered Extension Number

  63

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_surface`

Contact

  - Mathias Heyer mheyer

Last Modified Date

  2016-12-02

IP Status

  No known IP claims.

Contributors

  - Mathias Heyer, NVIDIA

  - Michael Chock, NVIDIA

  - Yasuhiro Yoshioka, Nintendo

  - Daniel Koch, NVIDIA

The `VK_NN_vi_surface` extension is an instance extension. It provides a mechanism to create a VkSurfaceKHR object (defined by the `VK_KHR_surface` extension) associated with an `nn`::`vi`::`Layer`.

#### New Object Types

None

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_VI_SURFACE_CREATE_INFO_NN`

#### New Enums

None

#### New Structures

- VkViSurfaceCreateInfoNN

#### New Functions

- vkCreateViSurfaceNN

#### Issues

1) Does VI need a way to query for compatibility between a particular physical device (and queue family?) and a specific VI display?

RESOLVED: No. It is currently always assumed that the device and display will always be compatible.

2) VkViSurfaceCreateInfoNN::`pWindow` is intended to store an `nn`::`vi`::`NativeWindowHandle`, but its declared type is a bare `void`* to store the window handle. Why the discrepancy?

RESOLVED: It is for C compatibility. The definition for the VI native window handle type is defined inside the `nn`::`vi` C++ namespace. This prevents its use in C source files. `nn`::`vi`::`NativeWindowHandle` is always defined to be `void`*, so this extension uses `void`* to match.

#### Version History

- Revision 1, 2016-12-2 (Michael Chock)

  - Initial draft.

#### VK_NV_clip_space_w_scaling

Name String

  `VK_NV_clip_space_w_scaling`

Extension Type

  Device extension

Registered Extension Number

  88

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Eric Werness ewerness-nv

Last Modified Date

  2017-02-15

Contributors

  - Eric Werness, NVIDIA

  - Kedarnath Thangudu, NVIDIA

Virtual Reality (VR) applications often involve a post-processing step to apply a “barrel” distortion to the rendered image to correct the “pincushion” distortion introduced by the optics in a VR device. The barrel distorted image has lower resolution along the edges compared to the center. Since the original image is rendered at high resolution, which is uniform across the complete image, a lot of pixels towards the edges do not make it to the final post-processed image.

This extension provides a mechanism to render VR scenes at a non-uniform resolution, in particular a resolution that falls linearly from the center towards the edges. This is achieved by scaling the w coordinate of the vertices in the clip space before perspective divide. The clip space w coordinate of the vertices can be offset as of a function of x and y coordinates as follows:

w' = w + Ax + By

In the intended use case for viewport position scaling, an application should use a set of four viewports, one for each of the four quadrants of a Cartesian coordinate system. Each viewport is set to the dimension of the image, but is scissored to the quadrant it represents. The application should specify A and B coefficients of the w-scaling equation above, that have the same value, but different signs, for each of the viewports. The signs of A and B should match the signs of x and y for the quadrant that they represent such that the value of w' will always be greater than or equal to the original w value for the entire image. Since the offset to w, (Ax + By), is always positive, and increases with the absolute values of x and y, the effective resolution will fall off linearly from the center of the image to its edges.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_W_SCALING_STATE_CREATE_INFO_NV`

- Extending VkDynamicState:

  - `VK_DYNAMIC_STATE_VIEWPORT_W_SCALING_NV`

#### New Enums

None.

#### New Structures

- VkViewportWScalingNV

- VkPipelineViewportWScalingStateCreateInfoNV

#### New Functions

- vkCmdSetViewportWScalingNV

#### Issues

1) Is the pipeline struct name too long?

RESOLVED: It fits with the naming convention.

2) Separate W scaling section or fold into coordinate transformations?

RESOLVED: Leaving it as its own section for now.

#### Examples

    VkViewport viewports[4];
    VkRect2D scissors[4];
    VkViewportWScalingNV scalings[4];

    for (int i = 0; i < 4; i++) {
        int x = (i & 2) ? 0 : currentWindowWidth / 2;
        int y = (i & 1) ? 0 : currentWindowHeight / 2;

        viewports[i].x = 0;
        viewports[i].y = 0;
        viewports[i].width = currentWindowWidth;
        viewports[i].height = currentWindowHeight;
        viewports[i].minDepth = 0.0f;
        viewports[i].maxDepth = 1.0f;

        scissors[i].offset.x = x;
        scissors[i].offset.y = y;
        scissors[i].extent.width = currentWindowWidth/2;
        scissors[i].extent.height = currentWindowHeight/2;

        const float factor = 0.15;
        scalings[i].xcoeff = ((i & 2) ? -1.0 : 1.0) * factor;
        scalings[i].ycoeff = ((i & 1) ? -1.0 : 1.0) * factor;
    }

    VkPipelineViewportWScalingStateCreateInfoNV vpWScalingStateInfo = { VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_W_SCALING_STATE_CREATE_INFO_NV };

    vpWScalingStateInfo.viewportWScalingEnable = VK_TRUE;
    vpWScalingStateInfo.viewportCount = 4;
    vpWScalingStateInfo.pViewportWScalings = &scalings[0];

    VkPipelineViewportStateCreateInfo vpStateInfo = { VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_STATE_CREATE_INFO };
    vpStateInfo.viewportCount = 4;
    vpStateInfo.pViewports = &viewports[0];
    vpStateInfo.scissorCount = 4;
    vpStateInfo.pScissors = &scissors[0];
    vpStateInfo.pNext = &vpWScalingStateInfo;

Example shader to read from a w-scaled texture:

    // Vertex Shader
    // Draw a triangle that covers the whole screen
    const vec4 positions[3] = vec4[3](vec4(-1, -1, 0, 1),
                                      vec4( 3, -1, 0, 1),
                                      vec4(-1,  3, 0, 1));
    out vec2 uv;
    void main()
    {
        vec4 pos = positions[ gl_VertexID ];
        gl_Position = pos;
        uv = pos.xy;
    }

    // Fragment Shader
    uniform sampler2D tex;
    uniform float xcoeff;
    uniform float ycoeff;
    out vec4 Color;
    in vec2 uv;

    void main()
    {
        // Handle uv as if upper right quadrant
        vec2 uvabs = abs(uv);

        // unscale: transform w-scaled image into an unscaled image
        //   scale: transform unscaled image int a w-scaled image
        float unscale = 1.0 / (1 + xcoeff * uvabs.x + xcoeff * uvabs.y);
        //float scale = 1.0 / (1 - xcoeff * uvabs.x - xcoeff * uvabs.y);

        vec2 P = vec2(unscale * uvabs.x, unscale * uvabs.y);

        // Go back to the right quadrant
        P *= sign(uv);

        Color = texture(tex, P * 0.5 + 0.5);
    }

#### Version History

- Revision 1, 2017-02-15 (Eric Werness)

  - Internal revisions

#### VK_NV_compute_shader_derivatives

Name String

  `VK_NV_compute_shader_derivatives`

Extension Type

  Device extension

Registered Extension Number

  202

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Pat Brown nvpbrown

Last Modified Date

  2018-07-19

IP Status

  No known IP claims.

Contributors

  - Pat Brown, NVIDIA

This extension adds Vulkan support for the `SPV_NV_compute_shader_derivatives` SPIR-V extension.

The SPIR-V extension provides two new execution modes, both of which allow compute shaders to use built-ins that evaluate compute derivatives explicitly or implicitly. Derivatives will be computed via differencing over a 2x2 group of shader invocations. The `DerivativeGroupQuadsNV` execution mode assembles shader invocations into 2x2 groups, where each group has x and y coordinates of the local invocation ID of the form (2m+{0,1}, 2n+{0,1}). The `DerivativeGroupLinearNV` execution mode assembles shader invocations into 2x2 groups, where each group has local invocation index values of the form 4m+{0,1,2,3}.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_COMPUTE_SHADER_DERIVATIVES_FEATURES_NV`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceComputeShaderDerivativesFeaturesNV

#### New Functions

None.

#### New SPIR-V Capability

- ComputeDerivativeGroupQuadsNV

- ComputeDerivativeGroupLinearNV

#### Issues

(1) Should we specify that the groups of four shader invocations used for derivatives in a compute shader are the same groups of four invocations that form a “quad” in shader subgroups?

RESOLVED: Yes.

#### Examples

None.

#### Version History

- Revision 1, 2018-07-19 (Pat Brown)

  - Initial draft

#### VK_NV_cooperative_matrix

Name String

  `VK_NV_cooperative_matrix`

Extension Type

  Device extension

Registered Extension Number

  250

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Jeff Bolz jeffbolznv

Last Modified Data

  2019-02-05

Contributors

  - Jeff Bolz, NVIDIA

  - Markus Tavenrath, NVIDIA

  - Daniel Koch, NVIDIA

This extension adds support for using cooperative matrix types in SPIR-V. Cooperative matrix types are medium-sized matrices that are primarily supported in compute shaders, where the storage for the matrix is spread across all invocations in some scope (usually a subgroup) and those invocations cooperate to efficiently perform matrix multiplies.

Cooperative matrix types are defined by the `SPV_NV_cooperative_matrix` SPIR-V extension and can be used with the `GL_NV_cooperative_matrix` GLSL extension.

This extension includes support for enumerating the matrix types and dimensions that are supported by the implementation.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_COOPERATIVE_MATRIX_FEATURES_NV`

  - `VK_STRUCTURE_TYPE_COOPERATIVE_MATRIX_PROPERTIES_NV`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_COOPERATIVE_MATRIX_PROPERTIES_NV`

#### New Enums

- VkScopeNV

- VkComponentTypeNV

#### New Structures

- Extending VkPhysicalDeviceFeatures2:

  - VkPhysicalDeviceCooperativeMatrixFeaturesNV

- Extending VkPhysicalDeviceProperties2:

  - VkPhysicalDeviceCooperativeMatrixPropertiesNV

- VkCooperativeMatrixPropertiesNV

#### New Functions

- vkGetPhysicalDeviceCooperativeMatrixPropertiesNV

#### New SPIR-V Capabilities

- CooperativeMatrixNV

#### Issues

(1) What matrix properties will be supported in practice?

RESOLVED: In NVIDIA’s initial implementation, we will support:

- AType = BType = fp16 CType = DType = fp16 MxNxK = 16x8x16 scope = Subgroup

- AType = BType = fp16 CType = DType = fp16 MxNxK = 16x8x8 scope = Subgroup

- AType = BType = fp16 CType = DType = fp32 MxNxK = 16x8x16 scope = Subgroup

- AType = BType = fp16 CType = DType = fp32 MxNxK = 16x8x8 scope = Subgroup

#### Version History

- Revision 1, 2019-02-05 (Jeff Bolz)

  - Internal revisions

#### VK_NV_corner_sampled_image

Name String

  `VK_NV_corner_sampled_image`

Extension Type

  Device extension

Registered Extension Number

  51

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Daniel Koch dgkoch

Last Modified Date

  2018-08-13

Contributors

  - Jeff Bolz, NVIDIA

  - Pat Brown, NVIDIA

  - Chris Lentini, NVIDIA

This extension adds support for a new image organization, which this extension refers to as “corner-sampled” images. A corner-sampled image differs from a conventional image in the following ways:

- Texels are centered on integer coordinates. See Unnormalized Texel Coordinate Operations

- Normalized coordinates are scaled using coord * (dim - 1) rather than coord * dim, where dim is the size of one dimension of the image. See normalized texel coordinate transform.

- Partial derivatives are scaled using coord * (dim - 1) rather than coord * dim. See Scale Factor Operation.

- Calculation of the next higher lod size goes according to ⌈dim / 2⌉ rather than ⌊dim / 2⌋. See Image Miplevel Sizing.

- The minimum level size is 2x2 for 2D images and 2x2x2 for 3D images. See Image Miplevel Sizing.

This image organization is designed to facilitate a system like Ptex with separate textures for each face of a subdivision or polygon mesh. Placing sample locations at pixel corners allows applications to maintain continuity between adjacent patches by duplicating values along shared edges. Additionally, using the modified mipmapping logic along with texture dimensions of the form 2n+1 allows continuity across shared edges even if the adjacent patches use different level-of-detail values.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_CORNER_SAMPLED_IMAGE_FEATURES_NV`

- Extending VkImageCreateFlagBits

  - `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceCornerSampledImageFeaturesNV

#### New Functions

None.

#### New Built-In Variables

None.

#### New SPIR-V Capabilities

None.

#### Issues

1. What should this extension be named?

   DISCUSSION: While naming this extension, we chose the most distinctive aspect of the image organization and referred to such images as “corner-sampled images”. As a result, we decided to name the extension NV_corner_sampled_image.

2. Do we need a format feature flag so formats can advertise if they support corner-sampling?

   DISCUSSION: Currently NVIDIA supports this for all 2D and 3D formats, but not for cubemaps or depth-stencil formats. A format feature might be useful if other vendors would only support this on some formats.

3. Do integer texel coordinates have a different range for corner-sampled images?

   RESOLVED: No, these are unchanged.

4. Do unnormalized sampler coordinates work with corner-sampled images? Are there any functional differences?

   RESOLVED: Yes they work. Unnormalized coordinates are treated as already scaled for corner-sample usage.

5. Should we have a diagram in the “Image Operations” chapter demonstrating different texel sampling locations?

   UNRESOLVED: Probaby, but later.

#### Version History

- Revision 1, 2018-08-14 (Daniel Koch)

  - Internal revisions

- Revision 2, 2018-08-14 (Daniel Koch)

  - ???

#### VK_NV_coverage_reduction_mode

Name String

  `VK_NV_coverage_reduction_mode`

Extension Type

  Device extension

Registered Extension Number

  251

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_NV_framebuffer_mixed_samples`

Contact

  - Kedarnath Thangudu kthangudu

Last Modified Date

  2019-01-29

Contributors

  - Kedarnath Thangudu, NVIDIA

  - Jeff Bolz, NVIDIA

When using a framebuffer with mixed samples, a per-fragment coverage reduction operation is performed which generates a color sample mask from the coverage mask. This extension defines the following modes to control how this reduction is performed.

- Merge: When there are more raster samples than color samples, there is an implementation dependent association of each raster sample to a color sample. In the merge mode, the reduced color sample mask is computed such that the bit for each color sample is 1 if any of the associated bits in the fragment’s coverage is on, and 0 otherwise. This is the default mode.

- Truncate: When there are more raster samples (N) than color samples(M), there is one to one association of the first M raster samples to the M color samples and the coverage bits for the other raster samples are ignored.

When the number of raster samples is equal to the color samples, there is a one to one mapping between them in either of the above modes.

The new command vkGetPhysicalDeviceSupportedFramebufferMixedSamplesCombinationsNV can be used to query the various raster, color, depth/stencil sample count and reduction mode combinations that are supported by the implementation. This extension would allow an implementation to support the behavior of both `VK_NV_framebuffer_mixed_samples` and `VK_AMD_mixed_attachment_samples` extensions simultaneously.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_COVERAGE_REDUCTION_MODE_FEATURES_NV`

  - `VK_STRUCTURE_TYPE_PIPELINE_COVERAGE_REDUCTION_STATE_CREATE_INFO_NV`

  - `VK_STRUCTURE_TYPE_FRAMEBUFFER_MIXED_SAMPLES_COMBINATION_NV`

#### New Enums

- VkCoverageReductionModeNV

- VkPipelineCoverageReductionStateCreateFlagsNV

#### New Structures

- VkPhysicalDeviceCoverageReductionModeFeaturesNV

- VkPipelineCoverageReductionStateCreateInfoNV

- VkFramebufferMixedSamplesCombinationNV

#### New Functions

- vkGetPhysicalDeviceSupportedFramebufferMixedSamplesCombinationsNV

#### Issues

None.

#### Version History

- Revision 1, 2019-01-29 (Kedarnath Thangudu)

  - Internal revisions

#### VK_NV_dedicated_allocation_image_aliasing

Name String

  `VK_NV_dedicated_allocation_image_aliasing`

Extension Type

  Device extension

Registered Extension Number

  241

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_dedicated_allocation`

Contact

  - Nuno Subtil nsubtil

Last Modified Date

  2019-01-04

Contributors

  - Nuno Subtil, NVIDIA

  - Jeff Bolz, NVIDIA

  - Eric Werness, NVIDIA

  - Axel Gneiting, id Software

This extension allows applications to alias images on dedicated allocations, subject to specific restrictions: the extent and the number of layers in the image being aliased must be smaller than or equal to those of the original image for which the allocation was created, and every other image parameter must match.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DEDICATED_ALLOCATION_IMAGE_ALIASING_FEATURES_NV`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceDedicatedAllocationImageAliasingFeaturesNV

#### New Functions

None.

#### Issues

None.

#### Version History

- Revision 1, 2019-01-04 (Nuno Subtil)

  - Internal revisions

#### VK_NV_device_diagnostic_checkpoints

Name String

  `VK_NV_device_diagnostic_checkpoints`

Extension Type

  Device extension

Registered Extension Number

  207

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Nuno Subtil nsubtil

Last Modified Date

  2018-07-16

Contributors

  - Oleg Kuznetsov, NVIDIA

  - Alex Dunn, NVIDIA

  - Jeff Bolz, NVIDIA

  - Eric Werness, NVIDIA

  - Daniel Koch, NVIDIA

This extension allows applications to insert markers in the command stream and associate them with custom data.

If a device lost error occurs, the application may then query the implementation for the last markers to cross specific implementation-defined pipeline stages, in order to narrow down which commands were executing at the time and might have caused the failure.

#### New Object Types

None.

#### New Enum Constants

Extending VkStructureType:

- `VK_STRUCTURE_TYPE_CHECKPOINT_DATA_NV`

- `VK_STRUCTURE_TYPE_QUEUE_FAMILY_CHECKPOINT_PROPERTIES_NV`

#### New Enums

None.

#### New Structures

- VkCheckpointDataNV

- VkQueueFamilyCheckpointPropertiesNV

#### New Functions

- vkCmdSetCheckpointNV

- vkGetQueueCheckpointDataNV

#### Issues

None yet!

#### Version History

- Revision 1, 2018-07-16 (Nuno Subtil)

  - Internal revisions

- Revision 2, 2018-07-16 (Nuno Subtil)

  - ???

#### VK_NV_device_diagnostics_config

Name String

  `VK_NV_device_diagnostics_config`

Extension Type

  Device extension

Registered Extension Number

  301

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Kedarnath Thangudu kthangudu

Last Modified Date

  2019-12-15

Contributors

  - Kedarnath Thangudu, NVIDIA

  - Thomas Klein, NVIDIA

Applications using Nvidia Nsight™ Aftermath SDK for Vulkan to integrate device crash dumps into their error reporting mechanisms, may use this extension to configure options related to device crash dump creation.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DIAGNOSTICS_CONFIG_FEATURES_NV`

  - `VK_STRUCTURE_TYPE_DEVICE_DIAGNOSTICS_CONFIG_CREATE_INFO_NV`

#### New Enums

- VkDeviceDiagnosticsConfigFlagsNV

- VkDeviceDiagnosticsConfigFlagBitsNV

#### New Structures

- VkPhysicalDeviceDiagnosticsConfigFeaturesNV

- VkDeviceDiagnosticsConfigCreateInfoNV

#### New Functions

None.

#### Issues

None.

#### Version History

- Revision 1, 2019-11-21 (Kedarnath Thangudu)

  - Internal revisions

#### VK_NV_device_generated_commands

Name String

  `VK_NV_device_generated_commands`

Extension Type

  Device extension

Registered Extension Number

  278

Revision

  3

Extension and Version Dependencies

  - Requires Vulkan 1.1

Contact

  - Christoph Kubisch pixeljetstream

Last Modified Date

  2020-02-20

Interactions and External Dependencies

  - This extension requires Vulkan 1.1

  - This extension requires `VK_EXT_buffer_device_address` or `VK_KHR_buffer_device_address` or Vulkan 1.2 for the ability to bind vertex and index buffers on the device.

  - This extension interacts with `VK_NV_mesh_shader`. If the latter extension is not supported, remove the command token to initiate mesh tasks drawing in this extension.

Contributors

  - Christoph Kubisch, NVIDIA

  - Pierre Boudier, NVIDIA

  - Jeff Bolz, NVIDIA

  - Eric Werness, NVIDIA

  - Yuriy O’Donnell, Epic Games

  - Baldur Karlsson, Valve

  - Mathias Schott, NVIDIA

  - Tyson Smith, NVIDIA

  - Ingo Esser, NVIDIA

This extension allows the device to generate a number of critical graphics commands for command buffers.

When rendering a large number of objects, the device can be leveraged to implement a number of critical functions, like updating matrices, or implementing occlusion culling, frustum culling, front to back sorting, etc. Implementing those on the device does not require any special extension, since an application is free to define its own data structures, and just process them using shaders.

However, if the application desires to quickly kick off the rendering of the final stream of objects, then unextended Vulkan forces the application to read back the processed stream and issue graphics command from the host. For very large scenes, the synchronization overhead and cost to generate the command buffer can become the bottleneck. This extension allows an application to generate a device side stream of state changes and commands, and convert it efficiently into a command buffer without having to read it back to the host.

Furthermore, it allows incremental changes to such command buffers by manipulating only partial sections of a command stream — for example pipeline bindings. Unextended Vulkan requires re-creation of entire command buffers in such a scenario, or updates synchronized on the host.

The intended usage for this extension is for the application to:

- create `VkBuffer` objects and retrieve physical addresses from them via vkGetBufferDeviceAddressEXT

- create a graphics pipeline using `VkGraphicsPipelineShaderGroupsCreateInfoNV` for the ability to change shaders on the device.

- create a VkIndirectCommandsLayoutNV, which lists the VkIndirectCommandsTokenTypeNV it wants to dynamically execute as an atomic command sequence. This step likely involves some internal device code compilation, since the intent is for the GPU to generate the command buffer in the pipeline.

- fill the input stream buffers with the data for each of the inputs it needs. Each input is an array that will be filled with token-dependent data.

- set up a preprocess `VkBuffer` that uses memory according to the information retrieved via vkGetGeneratedCommandsMemoryRequirementsNV.

- optionally preprocess the generated content using vkCmdPreprocessGeneratedCommandsNV, for example on an asynchronous compute queue, or for the purpose of re-using the data in multiple executions.

- call vkCmdExecuteGeneratedCommandsNV to create and execute the actual device commands for all sequences based on the inputs provided.

For each draw in a sequence, the following can be specified:

- a different shader group

- a number of vertex buffer bindings

- a different index buffer, with an optional dynamic offset and index type

- a number of different push constants

- a flag that encodes the primitive winding

While the GPU can be faster than a CPU to generate the commands, it will not happen asynchronously to the device, therefore the primary use-case is generating “less” total work (occlusion culling, classification to use specialized shaders, etc.).

#### New Object Types

- VkIndirectCommandsLayoutNV

#### New Flag Types

- VkIndirectCommandsLayoutUsageFlagsNV

- VkIndirectStateFlagsNV

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DEVICE_GENERATED_COMMANDS_FEATURES_NV`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DEVICE_GENERATED_COMMANDS_PROPERTIES_NV`

  - `VK_STRUCTURE_TYPE_GRAPHICS_SHADER_GROUP_CREATE_INFO_NV`

  - `VK_STRUCTURE_TYPE_GRAPHICS_PIPELINE_SHADER_GROUPS_CREATE_INFO_NV`

  - `VK_STRUCTURE_TYPE_INDIRECT_COMMANDS_LAYOUT_TOKEN_NV`

  - `VK_STRUCTURE_TYPE_INDIRECT_COMMANDS_LAYOUT_CREATE_INFO_NV`

  - `VK_STRUCTURE_TYPE_GENERATED_COMMANDS_INFO_NV`

  - `VK_STRUCTURE_TYPE_GENERATED_COMMANDS_MEMORY_REQUIREMENTS_INFO_NV`

- Extending VkPipelineCreateFlagBits:

  - `VK_PIPELINE_CREATE_INDIRECT_BINDABLE_BIT_NV`

- Extending VkPipelineStageFlagBits:

  - `VK_PIPELINE_STAGE_COMMAND_PREPROCESS_BIT_NV`

- Extending VkAccessFlagBits:

  - `VK_ACCESS_COMMAND_PREPROCESS_READ_BIT_NV`

  - `VK_ACCESS_COMMAND_PREPROCESS_WRITE_BIT_NV`

- Extending VkObjectType

  - `VK_OBJECT_TYPE_INDIRECT_COMMANDS_LAYOUT_NV`

#### New Enums

- VkIndirectStateFlagBitsNV

- VkIndirectCommandsLayoutUsageFlagBitsNV

- VkIndirectCommandsTokenTypeNV

#### New Structures

- VkPhysicalDeviceDeviceGeneratedCommandsFeaturesNV

- VkPhysicalDeviceDeviceGeneratedCommandsPropertiesNV

- VkGraphicsShaderGroupCreateInfoNV

- VkGraphicsPipelineShaderGroupsCreateInfoNV

- VkBindShaderGroupIndirectCommandNV

- VkBindIndexBufferIndirectCommandNV

- VkBindVertexBufferIndirectCommandNV

- VkSetStateFlagsIndirectCommandNV

- VkIndirectCommandsStreamNV

- VkIndirectCommandsLayoutTokenNV

- VkIndirectCommandsLayoutCreateInfoNV

- VkGeneratedCommandsInfoNV

- VkGeneratedCommandsMemoryRequirementsInfoNV

#### New Functions

- vkGetGeneratedCommandsMemoryRequirementsNV

- vkCmdPreprocessGeneratedCommandsNV

- vkCmdExecuteGeneratedCommandsNV

- vkCmdBindPipelineShaderGroupNV

- vkCreateIndirectCommandsLayoutNV

- vkDestroyIndirectCommandsLayoutNV

#### Issues

1) How to name this extension ?

`VK_NV_device_generated_commands`

As usual, one of the hardest issues ;)

Alternatives: `VK_gpu_commands`, `VK_execute_commands`, `VK_device_commands`, `VK_device_execute_commands`, `VK_device_execute`, `VK_device_created_commands`, `VK_device_recorded_commands`, `VK_device_generated_commands` `VK_indirect_generated_commands`

2) Should we use a serial stateful token stream or stateless sequence descriptions?

Similarly to VkPipeline, fixed layouts have the most likelihood to be cross-vendor adoptable. They also benefit from being processable in parallel. This is a different design choice compared to the serial command stream generated through `GL_NV_command_list`.

3) How to name a sequence description?

`VkIndirectCommandsLayout` as in the NVX extension predecessor.

Alternative: `VkGeneratedCommandsLayout`

4) Do we want to provide `indirectCommands` inputs with layout or at `indirectCommands` time?

Separate layout from data as Vulkan does. Provide full flexibility for `indirectCommands`.

5) Should the input be provided as SoA or AoS?

Both ways are desireable. AoS can provide portability to other APIs and easier to setup, while SoA allows to update individual inputs in a cache-efficient manner, when others remain static.

6) How do we make developers aware of the memory requirements of implementation-dependent data used for the generated commands?

Make the API explicit and introduce a `preprocess` VkBuffer. Developers have to allocate it using vkGetGeneratedCommandsMemoryRequirementsNV.

In the NVX version the requirements were hidden implicitly as part of the command buffer reservation process, however as the memory requirements can be substantial, we want to give developers the ability to budget the memory themselves. By lowering the `maxSequencesCount` the memory consumption can be reduced. Furthermore re-use of the memory is possible, for example for doing explicit preprocessing and execution in a ping-pong fashion.

The actual buffer size is implementation dependent and may be zero, i.e. not always required.

When making use of Graphics Shader Groups, the programs should behave similar with regards to vertex inputs, clipping and culling outputs of the geometry stage, as well as sample shading behavior in fragment shaders, to reduce the amount of the worst-case memory approximation.

7) Should we allow additional per-sequence dynamic state changes?

Yes

Introduced a lightweight indirect state flag VkIndirectStateFlagBitsNV. So far only switching front face winding state is exposed. Especially in CAD/DCC mirrored transforms that require such changes are common, and similar flexibility is given in the ray tracing instance description.

The flag could be extended further, for example to switch between primitive-lists or -strips, or make other state modifications.

Furthermore, as new tokens can be added easily, future extension could add the ability to change any VkDynamicState.

8) How do we allow re-using already “generated” `indirectCommands`?

Expose a `preprocessBuffer` to re-use implementation-dependencyFlags data. Set the `isPreprocessed` to true in vkCmdExecuteGeneratedCommandsNV.

9) Under which conditions is vkCmdExecuteGeneratedCommandsNV legal?

It behaves like a regular draw call command.

10) Is vkCmdPreprocessGeneratedCommandsNV copying the input data or referencing it?

There are multiple implementations possible:

- one could have some emulation code that parses the inputs, and generates an output command buffer, therefore copying the inputs.

- one could just reference the inputs, and have the processing done in pipe at execution time.

If the data is mandated to be copied, then it puts a penalty on implementation that could process the inputs directly in pipe. If the data is “referenced”, then it allows both types of implementation.

The inputs are “referenced”, and must not be modified after the call to vkCmdExecuteGeneratedCommandsNV has completed.

11) Which buffer usage flags are required for the buffers referenced by `VkGeneratedCommandsInfoNV` ?

Reuse existing `VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT`

- VkGeneratedCommandsInfoNV::`preprocessBuffer`

- VkGeneratedCommandsInfoNV::`sequencesCountBuffer`

- VkGeneratedCommandsInfoNV::`sequencesIndexBuffer`

- VkIndirectCommandsStreamNV::`buffer`

12) In which pipeline stage does the device generated command expansion happen?

vkCmdPreprocessGeneratedCommandsNV is treated as if it occurs in a separate logical pipeline from either graphics or compute, and that pipeline only includes `VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT`, a new stage `VK_PIPELINE_STAGE_COMMAND_PREPROCESS_BIT_NV`, and `VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT`. This new stage has two corresponding new access types, `VK_ACCESS_COMMAND_PREPROCESS_READ_BIT_NV` and `VK_ACCESS_COMMAND_PREPROCESS_WRITE_BIT_NV`, used to synchronize reading the buffer inputs and writing the preprocess memory output.

The generated output written in the preprocess buffer memory by vkCmdExecuteGeneratedCommandsNV is considered to be consumed by the `VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT` pipeline stage.

Thus, to synchronize from writing the input buffers to preprocessing via vkCmdPreprocessGeneratedCommandsNV, use:

- `dstStageMask` = `VK_PIPELINE_STAGE_COMMAND_PREPROCESS_BIT_NV`

- `dstAccessMask` = `VK_ACCESS_COMMAND_PREPROCESS_READ_BIT_NV`

To synchronize from vkCmdPreprocessGeneratedCommandsNV to executing the generated commands by vkCmdExecuteGeneratedCommandsNV, use:

- `srcStageMask` = `VK_PIPELINE_STAGE_COMMAND_PREPROCESS_BIT_NV`

- `srcAccessMask` = `VK_ACCESS_COMMAND_PREPROCESS_WRITE_BIT_NV`

- `dstStageMask` = `VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT`

- `dstAccessMask` = `VK_ACCESS_INDIRECT_COMMAND_READ_BIT`

When vkCmdExecuteGeneratedCommandsNV is used with a `isPreprocessed` of `VK_FALSE`, the generated commands are implicitly preprocessed, therefore one only needs to synchronize the inputs via:

- `dstStageMask` = `VK_PIPELINE_STAGE_DRAW_INDIRECT_BIT`

- `dstAccessMask` = `VK_ACCESS_INDIRECT_COMMAND_READ_BIT`

13) What if most token data is “static”, but we frequently want to render a subsection?

Added “sequencesIndexBuffer”. This allows to easier sort and filter what should actually be executed.

14) What are the changes compared to the previous NVX extension?

- Compute dispatch support was removed (was never implemented in drivers). There are different approaches how dispatching from the device should work, hence we defer this to a future extension.

- The `ObjectTableNVX` was replaced by using physical buffer addresses and introducing Shader Groups for the graphics pipeline.

- Less state changes are possible overall, but the important operations are still there (reduces complexity of implementation).

- The API was redesigned so all inputs must be passed at both preprocessing and execution time (this was implicit in NVX, now it is explicit)

- The reservation of intermediate command space is now mandatory and explicit through a preprocess buffer.

- The VkIndirectStateFlagBitsNV were introduced

15) When porting from other APIs, their indirect buffers may use different enums, for example for index buffer types. How to solve this?

Added “pIndexTypeValues” to map custom `uint32_t` values to corresponding `VkIndexType`.

16) Do we need more shader group state overrides?

The NVX version allowed all PSO states to be different, however as the goal is not to replace all state setup, but focus on highly-frequent state changes for drawing lots of objects, we reduced the amount of state overrides. Especially VkPipelineLayout as well as VkRenderPass configuration should be left static, the rest is still open for discussion.

The current focus is just to allow VertexInput changes as well as shaders, while all shader groups use the same shader stages.

Too much flexibility will increase the test coverage requirement as well. However, further extensions could allow more dynamic state as well.

17) Do we need more detailed physical device feature queries/enables?

An EXT version would need detailed implementor feedback to come up with a good set of features. Please contact us if you are interested, we are happy to make more features optional, or add further restrictions to reduce the minimum feature set of an EXT.

18) Is there an interaction with VK_KHR_pipeline_library planned?

Yes, a future version of this extension will detail the interaction, once VK_KHR_pipeline_library is no longer provisional.

#### Example Code

Open-Source samples illustrating the usage of the extension can be found at the following location (may not yet exist at time of writing):

https://github.com/nvpro-samples/vk_device_generated_cmds

#### Version History

- Revision 1, 2020-02-20 (Christoph Kubisch)

  - Initial version

#### VK_NV_fill_rectangle

Name String

  `VK_NV_fill_rectangle`

Extension Type

  Device extension

Registered Extension Number

  154

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Jeff Bolz jeffbolznv

Last Modified Date

  2017-05-22

Contributors

  - Jeff Bolz, NVIDIA

This extension adds a new VkPolygonMode `enum` where a triangle is rasterized by computing and filling its axis-aligned screen-space bounding box, disregarding the actual triangle edges. This can be useful for drawing a rectangle without being split into two triangles with an internal edge. It is also useful to minimize the number of primitives that need to be drawn, particularly for a user interface.

#### New Object Types

None.

#### New Enum Constants

- Extending VkPolygonMode

  - `VK_POLYGON_MODE_FILL_RECTANGLE_NV`

#### New Enums

None.

#### New Structures

None.

#### New Functions

None.

#### Issues

None.

#### Version History

- Revision 1, 2017-05-22 (Jeff Bolz)

  - Internal revisions

#### VK_NV_fragment_coverage_to_color

Name String

  `VK_NV_fragment_coverage_to_color`

Extension Type

  Device extension

Registered Extension Number

  150

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Jeff Bolz jeffbolznv

Last Modified Date

  2017-05-21

Contributors

  - Jeff Bolz, NVIDIA

This extension allows the fragment coverage value, represented as an integer bitmask, to be substituted for a color output being written to a single-component color attachment with integer components (e.g. `VK_FORMAT_R8_UINT`). The functionality provided by this extension is different from simply writing the `SampleMask` fragment shader output, in that the coverage value written to the framebuffer is taken after stencil test and depth test, as well as after fragment operations such as alpha-to-coverage.

This functionality may be useful for deferred rendering algorithms, where the second pass needs to know which samples belong to which original fragments.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PIPELINE_COVERAGE_TO_COLOR_STATE_CREATE_INFO_NV`

#### New Enums

- VkPipelineCoverageToColorStateCreateFlagsNV

#### New Structures

- VkPipelineCoverageToColorStateCreateInfoNV

#### New Functions

None.

#### Issues

None.

#### Version History

- Revision 1, 2017-05-21 (Jeff Bolz)

  - Internal revisions

#### VK_NV_fragment_shader_barycentric

Name String

  `VK_NV_fragment_shader_barycentric`

Extension Type

  Device extension

Registered Extension Number

  204

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Pat Brown nvpbrown

Last Modified Date

  2018-08-03

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Requires the `SPV_NV_fragment_shader_barycentric` SPIR-V extension.

  - Requires the `GL_NV_fragment_shader_barycentric` extension for GLSL source languages.

Contributors

  - Pat Brown, NVIDIA

  - Daniel Koch, NVIDIA

This extension adds support for the following SPIR-V extension in Vulkan:

- `SPV_NV_fragment_shader_barycentric`

The extension provides access to three additional fragment shader variable decorations in SPIR-V:

- `PerVertexNV`, which indicates that a fragment shader input will not have interpolated values, but instead must be accessed with an extra array index that identifies one of the vertices of the primitive producing the fragment

- `BaryCoordNV`, which indicates that the variable is a three-component floating-point vector holding barycentric weights for the fragment produced using perspective interpolation

- `BaryCoordNoPerspNV`, which indicates that the variable is a three-component floating-point vector holding barycentric weights for the fragment produced using linear interpolation

When using GLSL source-based shader languages, the following variables from `GL_NV_fragment_shader_barycentric` maps to these SPIR-V built-in decorations:

- `in vec3 gl_BaryCoordNV;` → `BaryCoordNV`

- `in vec3 gl_BaryCoordNoPerspNV;` → `BaryCoordNoPerspNV`

GLSL variables declared using the `__pervertexNV` GLSL qualifier are expected to be decorated with `PerVertexNV` in SPIR-V.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FRAGMENT_SHADER_BARYCENTRIC_FEATURES_NV`

#### New Enums

None.

#### New Structures

None.

#### New Functions

None.

#### New Built-In Variables

- `BaryCoordNV`

- `BaryCoordNoPerspNV`

#### New SPIR-V Decorations

- `PerVertexNV`

#### New SPIR-V Capabilities

- `FragmentBarycentricNV`

#### Issues

(1) The AMD_shader_explicit_vertex_parameter extension provides similar functionality. Why write a new extension, and how is this extension different?

RESOLVED: For the purposes of Vulkan/SPIR-V, we chose to implement a separate extension due to several functional differences.

First, the hardware supporting this extension can provide a three-component barycentric weight vector for variables decorated with `BaryCoordNV`, while variables decorated with `BaryCoordSmoothAMD` provide only two components. In some cases, it may be more efficient to explicitly interpolate an attribute via:

    float value = (baryCoordNV.x * v[0].attrib +
                   baryCoordNV.y * v[1].attrib +
                   baryCoordNV.z * v[2].attrib);

instead of

    float value = (baryCoordSmoothAMD.x * (v[0].attrib - v[2].attrib) +
                   baryCoordSmoothAMD.y * (v[1].attrib - v[2].attrib) +
                   v[2].attrib);

Additionally, the semantics of the decoration `BaryCoordPullModelAMD` do not appear to map to anything supported by the initial hardware implementation of this extension.

This extension provides a smaller number of decorations than the AMD extension, as we expect that shaders could derive variables decorated with things like `BaryCoordNoPerspCentroidAMD` with explicit attribute interpolation instructions. One other relevant difference is that explicit per-vertex attribute access using this extension does not require a constant vertex number.

(2) Why do the built-in SPIR-V decorations for this extension include two separate built-ins `BaryCoordNV` and `BaryCoordNoPerspNV` when a “no perspective” variable could be decorated with `BaryCoordNV` and `NoPerspective`?

RESOLVED: The SPIR-V extension for this feature chose to mirror the behavior of the GLSL extension, which provides two built-in variables. Additionally, it’s not clear that its a good idea (or even legal) to have two variables using the “same attribute”, but with different interpolation modifiers.

#### Version History

- Revision 1, 2018-08-03 (Pat Brown)

  - Internal revisions

#### VK_NV_framebuffer_mixed_samples

Name String

  `VK_NV_framebuffer_mixed_samples`

Extension Type

  Device extension

Registered Extension Number

  153

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Jeff Bolz jeffbolznv

Last Modified Date

  2017-06-04

Contributors

  - Jeff Bolz, NVIDIA

This extension allows multisample rendering with a raster and depth/stencil sample count that is larger than the color sample count. Rasterization and the results of the depth and stencil tests together determine the portion of a pixel that is “covered”. It can be useful to evaluate coverage at a higher frequency than color samples are stored. This coverage is then “reduced” to a collection of covered color samples, each having an opacity value corresponding to the fraction of the color sample covered. The opacity can optionally be blended into individual color samples.

Rendering with fewer color samples than depth/stencil samples greatly reduces the amount of memory and bandwidth consumed by the color buffer. However, converting the coverage values into opacity introduces artifacts where triangles share edges and may not be suitable for normal triangle mesh rendering.

One expected use case for this functionality is Stencil-then-Cover path rendering (similar to the OpenGL GL_NV_path_rendering extension). The stencil step determines the coverage (in the stencil buffer) for an entire path at the higher sample frequency, and then the cover step draws the path into the lower frequency color buffer using the coverage information to antialias path edges. With this two-step process, internal edges are fully covered when antialiasing is applied and there is no corruption on these edges.

The key features of this extension are:

- It allows render pass and framebuffer objects to be created where the number of samples in the depth/stencil attachment in a subpass is a multiple of the number of samples in the color attachments in the subpass.

- A coverage reduction step is added to Fragment Operations which converts a set of covered raster/depth/stencil samples to a set of color samples that perform blending and color writes. The coverage reduction step also includes an optional coverage modulation step, multiplying color values by a fractional opacity corresponding to the number of associated raster/depth/stencil samples covered.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType

  - `VK_STRUCTURE_TYPE_PIPELINE_COVERAGE_MODULATION_STATE_CREATE_INFO_NV`

#### New Enums

- VkCoverageModulationModeNV

- VkPipelineCoverageModulationStateCreateFlagsNV

#### New Structures

- VkPipelineCoverageModulationStateCreateInfoNV

#### New Functions

None.

#### Issues

None.

#### Version History

- Revision 1, 2017-06-04 (Jeff Bolz)

  - Internal revisions

#### VK_NV_geometry_shader_passthrough

Name String

  `VK_NV_geometry_shader_passthrough`

Extension Type

  Device extension

Registered Extension Number

  96

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Daniel Koch dgkoch

Last Modified Date

  2017-02-15

Interactions and External Dependencies

  - This extension requires the `SPV_NV_geometry_shader_passthrough` SPIR-V extension.

  - This extension requires the `GL_NV_geometry_shader_passthrough` extension for GLSL source languages.

  - This extension requires the `geometryShader` feature.

Contributors

  - Piers Daniell, NVIDIA

  - Jeff Bolz, NVIDIA

This extension adds support for the following SPIR-V extension in Vulkan:

- `SPV_NV_geometry_shader_passthrough`

Geometry shaders provide the ability for applications to process each primitive sent through the graphics pipeline using a programmable shader. However, one common use case treats them largely as a “passthrough”. In this use case, the bulk of the geometry shader code simply copies inputs from each vertex of the input primitive to corresponding outputs in the vertices of the output primitive. Such shaders might also compute values for additional built-in or user-defined per-primitive attributes (e.g., `Layer`) to be assigned to all the vertices of the output primitive.

This extension provides access to the `PassthroughNV` decoration under the `GeometryShaderPassthroughNV` capability. Adding this to a geometry shader input variable specifies that the values of this input are copied to the corresponding vertex of the output primitive.

When using GLSL source-based shading languages, the `passthrough` layout qualifier from `GL_NV_geometry_shader_passthrough` maps to the `PassthroughNV` decoration. To use the `passthrough` layout, in GLSL the `GL_NV_geometry_shader_passthrough` extension must be enabled. Behaviour is described in the `GL_NV_geometry_shader_passthrough` extension specification.

#### New Object Types

None.

#### New Enum Constants

None.

#### New Enums

None.

#### New Structures

None.

#### New Functions

None.

#### New Built-In Variables

None.

#### New Variable Decoration

- `PassthroughNV` in Geometry Shader Passthrough

#### New SPIR-V Capabilities

- GeometryShaderPassthroughNV

#### Issues

1) Should we require or allow a passthrough geometry shader to specify the output layout qualifiers for the output primitive type and maximum vertex count in the SPIR-V?

RESOLVED: Yes they should be required in the SPIR-V. Per GL_NV_geometry_shader_passthrough they are not permitted in the GLSL source shader, but SPIR-V is lower-level. It is straightforward for the GLSL compiler to infer them from the input primitive type and to explicitly emit them in the SPIR-V according to the following table.

Input Layout | Implied Output Layout
--- | ---
points | `layout(points, max_vertices=1)`
lines | `layout(line_strip, max_vertices=2)`
triangles | `layout(triangle_strip, max_vertices=3)`

2) How does interface matching work with passthrough geometry shaders?

RESOLVED: This is described in Passthrough Interface Matching. In GL when using passthough geometry shaders in separable mode, all inputs must also be explicitly assigned location layout qualifiers. In Vulkan all SPIR-V shader inputs (except built-ins) must also have location decorations specified. Redeclarations of built-in varables that add the passthrough layout qualifier are exempted from the rule requiring location assignment because built-in variables do not have locations and are matched by `BuiltIn` decoration.

#### Sample Code

Consider the following simple geometry shader in unextended GLSL:

    layout(triangles) in;
    layout(triangle_strip) out;
    layout(max_vertices=3) out;

    in Inputs {
        vec2 texcoord;
        vec4 baseColor;
    } v_in[];
    out Outputs {
        vec2 texcoord;
        vec4 baseColor;
    };

    void main()
    {
        int layer = compute_layer();
        for (int i = 0; i < 3; i++) {
            gl_Position = gl_in[i].gl_Position;
            texcoord = v_in[i].texcoord;
            baseColor = v_in[i].baseColor;
            gl_Layer = layer;
            EmitVertex();
        }
    }

In this shader, the inputs `gl_Position`, `Inputs.texcoord`, and `Inputs.baseColor` are simply copied from the input vertex to the corresponding output vertex. The only “interesting” work done by the geometry shader is computing and emitting a `gl_Layer` value for the primitive.

The following geometry shader, using this extension, is equivalent:

    #extension GL_NV_geometry_shader_passthrough : require

    layout(triangles) in;
    // No output primitive layout qualifiers required.

    // Redeclare gl_PerVertex to pass through "gl_Position".
    layout(passthrough) in gl_PerVertex {
        vec4 gl_Position;
    } gl_in[];

    // Declare "Inputs" with "passthrough" to automatically copy members.
    layout(passthrough) in Inputs {
        vec2 texcoord;
        vec4 baseColor;
    } v_in[];

    // No output block declaration required.

    void main()
    {
        // The shader simply computes and writes gl_Layer.  We don't
        // loop over three vertices or call EmitVertex().
        gl_Layer = compute_layer();
    }

#### Version History

- Revision 1, 2017-02-15 (Daniel Koch)

  - Internal revisions

#### VK_NV_mesh_shader

Name String

  `VK_NV_mesh_shader`

Extension Type

  Device extension

Registered Extension Number

  203

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Christoph Kubisch pixeljetstream

Last Modified Date

  2018-07-19

Contributors

  - Pat Brown, NVIDIA

  - Jeff Bolz, NVIDIA

  - Daniel Koch, NVIDIA

  - Piers Daniell, NVIDIA

  - Pierre Boudier, NVIDIA

This extension provides a new mechanism allowing applications to generate collections of geometric primitives via programmable mesh shading. It is an alternative to the existing programmable primitive shading pipeline, which relied on generating input primitives by a fixed function assembler as well as fixed function vertex fetch.

There are new programmable shader types — the task and mesh shader — to generate these collections to be processed by fixed-function primitive assembly and rasterization logic. When the task and mesh shaders are dispatched, they replace the standard programmable vertex processing pipeline, including vertex array attribute fetching, vertex shader processing, tessellation, and the geometry shader processing.

This extension also adds support for the following SPIR-V extension in Vulkan:

- `SPV_NV_mesh_shader`

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MESH_SHADER_FEATURES_NV`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MESH_SHADER_PROPERTIES_NV`

- Extending VkShaderStageFlagBits

  - `VK_SHADER_STAGE_TASK_BIT_NV`

  - `VK_SHADER_STAGE_MESH_BIT_NV`

- Extending VkPipelineStageFlagBits

  - `VK_PIPELINE_STAGE_TASK_SHADER_BIT_NV`

  - `VK_PIPELINE_STAGE_MESH_SHADER_BIT_NV`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceMeshShaderFeaturesNV

- VkPhysicalDeviceMeshShaderPropertiesNV

- VkDrawMeshTasksIndirectCommandNV

#### New Functions

- vkCmdDrawMeshTasksNV

- vkCmdDrawMeshTasksIndirectNV

- vkCmdDrawMeshTasksIndirectCountNV

#### New or Modified Built-In Variables

- TaskCountNV

- PrimitiveCountNV

- PrimitiveIndicesNV

- ClipDistancePerViewNV

- CullDistancePerViewNV

- LayerPerViewNV

- MeshViewCountNV

- MeshViewIndicesNV

- (modified)`Position`

- (modified)`PointSize`

- (modified)`ClipDistance`

- (modified)`CullDistance`

- (modified)`PrimitiveId`

- (modified)`Layer`

- (modified)`ViewportIndex`

- (modified)`WorkgroupSize`

- (modified)`WorkgroupId`

- (modified)`LocalInvocationId`

- (modified)`GlobalInvocationId`

- (modified)`LocalInvocationIndex`

- (modified)`DrawIndex`

- (modified)`ViewportMaskNV`

- (modified)`PositionPerViewNV`

- (modified)`ViewportMaskPerViewNV`

#### New SPIR-V Capability

- MeshShadingNV

#### Issues

1. How to name this extension?

   RESOLVED: VK_NV_mesh_shader

   Other options considered:

   - VK_NV_mesh_shading

   - VK_NV_programmable_mesh_shading

   - VK_NV_primitive_group_shading

   - VK_NV_grouped_drawing

2. Do we need a new VkPrimitiveTopology?

   RESOLVED: NO, we skip the InputAssembler stage

3. Should we allow Instancing?

   RESOLVED: NO, there is no fixed function input, other than the IDs. However, allow offsetting with a "first" value.

4. Should we use existing vkCmdDraw or introduce new functions?

   RESOLVED: Introduce new functions.

   New functions make it easier to separate from "programmable primitive shading" chapter, less "dual use" language about existing functions having alternative behavior. The text around the existing "draws" is heavily based around emitting vertices.

5. If new functions, how to name?

   RESOLVED: CmdDrawMeshTasks*

   Other options considered:

   - CmdDrawMeshed

   - CmdDrawTasked

   - CmdDrawGrouped

6. Should VK_SHADER_STAGE_ALL_GRAPHICS be updated to include the new stages?

   RESOLVED: No. If an application were to be recompiled with headers that include additional shader stage bits in VK_SHADER_STAGE_ALL_GRAPHICS, then the previously valid application would no longer be valid on implementations that don’t support mesh or task shaders. This means the change would not be backwards compatible. It’s too bad VkShaderStageFlagBits doesn’t have a dedicated "all supported graphics stages" bit like VK_PIPELINE_STAGE_ALL_GRAPHICS_BIT, which would have avoided this problem.

#### Version History

- Revision 1, 2018-07-19 (Christoph Kubisch, Daniel Koch)

  - Internal revisions

#### VK_NV_ray_tracing

Name String

  `VK_NV_ray_tracing`

Extension Type

  Device extension

Registered Extension Number

  166

Revision

  3

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

  - Requires `VK_KHR_get_memory_requirements2`

Contact

  - Eric Werness ewerness

Last Modified Date

  2018-11-20

Interactions and External Dependencies

  - This extension requires the `SPV_NV_ray_tracing` SPIR-V extension.

  - This extension requires the `GL_NV_ray_tracing` extension for GLSL source languages.

Contributors

  - Eric Werness, NVIDIA

  - Ashwin Lele, NVIDIA

  - Robert Stepinski, NVIDIA

  - Nuno Subtil, NVIDIA

  - Christoph Kubisch, NVIDIA

  - Martin Stich, NVIDIA

  - Daniel Koch, NVIDIA

  - Jeff Bolz, NVIDIA

  - Joshua Barczak, Intel

  - Tobias Hector, AMD

  - Henrik Rydgard, NVIDIA

  - Pascal Gautron, NVIDIA

Rasterization has been the dominant method to produce interactive graphics, but increasing performance of graphics hardware has made ray tracing a viable option for interactive rendering. Being able to integrate ray tracing with traditional rasterization makes it easier for applications to incrementally add ray traced effects to existing applications or to do hybrid approaches with rasterization for primary visibility and ray tracing for secondary queries.

To enable ray tracing, this extension adds a few different categories of new functionality:

- Acceleration structure objects and build commands

- A new pipeline type with new shader domains

- An indirection table to link shader groups with acceleration structure items

This extension adds support for the following SPIR-V extension in Vulkan:

- `SPV_NV_ray_tracing`

#### New Object Types

- VkAccelerationStructureNV

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_RAY_TRACING_PIPELINE_CREATE_INFO_NV`

  - `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_CREATE_INFO_NV`

  - `VK_STRUCTURE_TYPE_GEOMETRY_NV`

  - `VK_STRUCTURE_TYPE_GEOMETRY_TRIANGLES_NV`

  - `VK_STRUCTURE_TYPE_GEOMETRY_AABB_NV`

  - `VK_STRUCTURE_TYPE_BIND_ACCELERATION_STRUCTURE_MEMORY_INFO_NV`

  - `VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET_ACCELERATION_STRUCTURE_NV`

  - `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_INFO_NV`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_RAY_TRACING_PROPERTIES_NV`

  - `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_INFO_NV`

  - `VK_STRUCTURE_TYPE_RAY_TRACING_SHADER_GROUP_CREATE_INFO_NV`

- Extending VkShaderStageFlagBits:

  - `VK_SHADER_STAGE_RAYGEN_BIT_NV`

  - `VK_SHADER_STAGE_ANY_HIT_BIT_NV`

  - `VK_SHADER_STAGE_CLOSEST_HIT_BIT_NV`

  - `VK_SHADER_STAGE_MISS_BIT_NV`

  - `VK_SHADER_STAGE_INTERSECTION_BIT_NV`

  - `VK_SHADER_STAGE_CALLABLE_BIT_NV`

- Extending VkPipelineStageFlagBits:

  - `VK_PIPELINE_STAGE_RAY_TRACING_SHADER_BIT_NV`

  - `VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_NV`

- Extending VkBufferUsageFlagBits:

  - `VK_BUFFER_USAGE_RAY_TRACING_BIT_NV`

- Extending VkPipelineBindPoint:

  - `VK_PIPELINE_BIND_POINT_RAY_TRACING_NV`

- Extending VkDescriptorType:

  - `VK_DESCRIPTOR_TYPE_ACCELERATION_STRUCTURE_NV`

- Extending VkAccessFlagBits:

  - `VK_ACCESS_ACCELERATION_STRUCTURE_READ_BIT_NV`

  - `VK_ACCESS_ACCELERATION_STRUCTURE_WRITE_BIT_NV`

- Extending VkQueryType:

  - `VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_NV`

- Extending VkPipelineCreateFlagBits:

  - `VK_PIPELINE_CREATE_DEFER_COMPILE_BIT_NV`

- Extending VkIndexType:

  - `VK_INDEX_TYPE_NONE_NV`

#### New Enums

- VkGeometryFlagBitsNV

- VkGeometryInstanceFlagBitsNV

- VkBuildAccelerationStructureFlagBitsNV

- VkCopyAccelerationStructureModeNV

- VkGeometryTypeNV

- VkRayTracingShaderGroupTypeNV

- VkAccelerationStructureMemoryRequirementsTypeNV

- VkAccelerationStructureTypeNV

#### New Structures

- VkRayTracingPipelineCreateInfoNV

- VkGeometryTrianglesNV

- VkGeometryAABBNV

- VkGeometryDataNV

- VkGeometryNV

- VkAccelerationStructureCreateInfoNV

- VkBindAccelerationStructureMemoryInfoNV

- VkWriteDescriptorSetAccelerationStructureNV

- VkAccelerationStructureMemoryRequirementsInfoNV

- VkPhysicalDeviceRayTracingPropertiesNV

- VkRayTracingShaderGroupCreateInfoNV

- VkAccelerationStructureInfoNV

#### New Functions

- vkCreateAccelerationStructureNV

- vkDestroyAccelerationStructureNV

- vkGetAccelerationStructureMemoryRequirementsNV

- vkBindAccelerationStructureMemoryNV

- vkCmdBuildAccelerationStructureNV

- vkCmdCopyAccelerationStructureNV

- vkCmdTraceRaysNV

- vkCreateRayTracingPipelinesNV

- vkGetRayTracingShaderGroupHandlesNV

- vkGetAccelerationStructureHandleNV

- vkCmdWriteAccelerationStructuresPropertiesNV

- vkCompileDeferredNV

#### New or Modified Built-In Variables

- `LaunchIDNV`

- `LaunchSizeNV`

- `WorldRayOriginNV`

- `WorldRayDirectionNV`

- `ObjectRayOriginNV`

- `ObjectRayDirectionNV`

- `RayTminNV`

- `RayTmaxNV`

- `InstanceCustomIndexNV`

- `InstanceId`

- `ObjectToWorldNV`

- `WorldToObjectNV`

- `HitTNV`

- `HitKindNV`

- `IncomingRayFlagsNV`

- (modified)`PrimitiveId`

#### New SPIR-V Capabilities

- RayTracingNV

#### Issues

1) Are there issues?

RESOLVED: Yes.

#### Sample Code

Example ray generation GLSL shader

    #version 450 core
    #extension GL_NV_ray_tracing : require
    layout(set = 0, binding = 0, rgba8) uniform image2D image;
    layout(set = 0, binding = 1) uniform accelerationStructureNV as;
    layout(location = 0) rayPayloadNV float payload;

    void main()
    {
       vec4 col = vec4(0, 0, 0, 1);

       vec3 origin = vec3(float(gl_LaunchIDNV.x)/float(gl_LaunchSizeNV.x), float(gl_LaunchIDNV.y)/float(gl_LaunchSizeNV.y), 1.0);
       vec3 dir = vec3(0.0, 0.0, -1.0);

       traceNV(as, 0, 0xff, 0, 1, 0, origin, 0.0, dir, 1000.0, 0);

       col.y = payload;

       imageStore(image, ivec2(gl_LaunchIDNV.xy), col);
    }

#### Version History

- Revision 1, 2018-09-11 (Robert Stepinski, Nuno Subtil, Eric Werness)

  - Internal revisions

- Revision 2, 2018-10-19 (Eric Werness)

  - rename to VK_NV_ray_tracing, add support for callables.

  - too many updates to list

- Revision 3, 2018-11-20 (Daniel Koch)

  - update to use InstanceId instead of InstanceIndex as implemented.

#### VK_NV_representative_fragment_test

Name String

  `VK_NV_representative_fragment_test`

Extension Type

  Device extension

Registered Extension Number

  167

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Kedarnath Thangudu kthangudu

Last Modified Date

  2018-09-13

Contributors

  - Kedarnath Thangudu, NVIDIA

  - Christoph Kubisch, NVIDIA

  - Pierre Boudier, NVIDIA

  - Pat Brown, NVIDIA

  - Jeff Bolz, NVIDIA

  - Eric Werness, NVIDIA

This extension provides a new representative fragment test that allows implementations to reduce the amount of rasterization and fragment processing work performed for each point, line, or triangle primitive. For any primitive that produces one or more fragments that pass all other early fragment tests, the implementation is permitted to choose one or more “representative” fragments for processing and discard all other fragments. For draw calls rendering multiple points, lines, or triangles arranged in lists, strips, or fans, the representative fragment test is performed independently for each of those primitives.

This extension is useful for applications that use an early render pass to determine the full set of primitives that would be visible in the final scene. In this render pass, such applications would set up a fragment shader that enables early fragment tests and writes to an image or shader storage buffer to record the ID of the primitive that generated the fragment. Without this extension, the shader would record the ID separately for each visible fragment of each primitive. With this extension, fewer stores will be performed, particularly for large primitives.

The representative fragment test has no effect if early fragment tests are not enabled via the fragment shader. The set of fragments discarded by the representative fragment test is implementation-dependent and may vary from frame to frame. In some cases, the representative fragment test may not discard any fragments for a given primitive.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_REPRESENTATIVE_FRAGMENT_TEST_FEATURES_NV`

  - `VK_STRUCTURE_TYPE_PIPELINE_REPRESENTATIVE_FRAGMENT_TEST_STATE_CREATE_INFO_NV`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceRepresentativeFragmentTestFeaturesNV

- VkPipelineRepresentativeFragmentTestStateCreateInfoNV

#### New Functions

None.

#### Issues

(1) Is the representative fragment test guaranteed to have any effect?

RESOLVED: No. As specified, we only guarantee that each primitive with at least one fragment that passes prior tests will have one fragment passing the representative fragment tests. We don’t guarantee that any particular fragment will fail the test.

In the initial implementation of this extension, the representative fragment test is treated as an optimization that may be completely disabled for some pipeline states. This feature was designed for a use case where the fragment shader records information on individual primitives using shader storage buffers or storage images, with no writes to color or depth buffers.

(2) Will the set of fragments that pass the representative fragment test be repeatable if you draw the same scene over and over again?

RESOLVED: No. The set of fragments that pass the representative fragment test is implementation-dependent and may vary due to the timing of operations performed by the GPU.

(3) What happens if you enable the representative fragment test with writes to color and/or depth render targets enabled?

RESOLVED: If writes to the color or depth buffer are enabled, they will be performed for any fragments that survive the relevant tests. Any fragments that fail the representative fragment test will not update color buffers. For the use cases intended for this feature, we don’t expect color or depth writes to be enabled.

(4) How do derivatives and automatic texture level of detail computations work with the representative fragment test enabled?

RESOLVED: If a fragment shader uses derivative functions or texture lookups using automatic level of detail computation, derivatives will be computed identically whether or not the representative fragment test is enabled. For the use cases intended for this feature, we don’t expect the use of derivatives in the fragment shader.

#### Version History

- Revision 2, 2018-09-13 (pbrown)

  - Add issues.

- Revision 1, 2018-08-22 (Kedarnath Thangudu)

  - Internal Revisions

#### VK_NV_sample_mask_override_coverage

Name String

  `VK_NV_sample_mask_override_coverage`

Extension Type

  Device extension

Registered Extension Number

  95

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Piers Daniell pdaniell-nv

Last Modified Date

  2016-12-08

IP Status

  No known IP claims.

Interactions and External Dependencies

  - This extension requires the `SPV_NV_sample_mask_override_coverage` SPIR-V extension.

  - This extension requires the `GL_NV_sample_mask_override_coverage` extension for GLSL source languages.

Contributors

  - Daniel Koch, NVIDIA

  - Jeff Bolz, NVIDIA

This extension adds support for the following SPIR-V extension in Vulkan:

- `SPV_NV_sample_mask_override_coverage`

The extension provides access to the `OverrideCoverageNV` decoration under the `SampleMaskOverrideCoverageNV` capability. Adding this decoration to a variable with the `SampleMask` builtin decoration allows the shader to modify the coverage mask and affect which samples are used to process the fragment.

When using GLSL source-based shader languages, the `override_coverage` layout qualifier from `GL_NV_sample_mask_override_coverage` maps to the `OverrideCoverageNV` decoration. To use the `override_coverage` layout qualifier in GLSL the `GL_NV_sample_mask_override_coverage` extension must be enabled. Behavior is described in the `GL_NV_sample_mask_override_coverage` extension spec.

#### New Object Types

None.

#### New Enum Constants

None.

#### New Enums

None.

#### New Structures

None.

#### New Functions

None.

#### New Built-In Variables

None.

#### New Variable Decoration

- OverrideCoverageNV in SampleMask

#### New SPIR-V Capabilities

- SampleMaskOverrideCoverageNV

#### Issues

None.

#### Version History

- Revision 1, 2016-12-08 (Piers Daniell)

  - Internal revisions

#### VK_NV_scissor_exclusive

Name String

  `VK_NV_scissor_exclusive`

Extension Type

  Device extension

Registered Extension Number

  206

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Pat Brown nvpbrown

Last Modified Date

  2018-07-31

IP Status

  No known IP claims.

Interactions and External Dependencies

  None

Contributors

  - Pat Brown, NVIDIA

  - Jeff Bolz, NVIDIA

  - Piers Daniell, NVIDIA

  - Daniel Koch, NVIDIA

This extension adds support for an exclusive scissor test to Vulkan. The exclusive scissor test behaves like the scissor test, except that the exclusive scissor test fails for pixels inside the corresponding rectangle and passes for pixels outside the rectangle. If the same rectangle is used for both the scissor and exclusive scissor tests, the exclusive scissor test will pass if and only if the scissor test fails.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType

  - `VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_EXCLUSIVE_SCISSOR_STATE_CREATE_INFO_NV`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXCLUSIVE_SCISSOR_FEATURES_NV`

- Extending VkDynamicState

  - `VK_DYNAMIC_STATE_EXCLUSIVE_SCISSOR_NV`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceExclusiveScissorFeaturesNV

- VkPipelineViewportExclusiveScissorStateCreateInfoNV

#### New Functions

- vkCmdSetExclusiveScissorNV

#### New Built-In Variables

None.

#### New SPIR-V Capabilities

None.

#### Issues

1) For the scissor test, the viewport state must be created with a matching number of scissor and viewport rectangles. Should we have the same requirement for exclusive scissors?

RESOLVED: For exclusive scissors, we relax this requirement and allow an exclusive scissor rectangle count that is either zero or equal to the number of viewport rectangles. If you pass in an exclusive scissor count of zero, the exclusive scissor test is treated as disabled.

#### Version History

- Revision 1, 2018-07-31 (Pat Brown)

  - Internal revisions

#### VK_NV_shader_image_footprint

Name String

  `VK_NV_shader_image_footprint`

Extension Type

  Device extension

Registered Extension Number

  205

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Pat Brown nvpbrown

Last Modified Date

  2018-09-13

IP Status

  No known IP claims.

Contributors

  - Pat Brown, NVIDIA

  - Chris Lentini, NVIDIA

  - Daniel Koch, NVIDIA

  - Jeff Bolz, NVIDIA

This extension adds Vulkan support for the `SPV_NV_shader_image_footprint` SPIR-V extension. That SPIR-V extension provides a new instruction `OpImageSampleFootprintNV` allowing shaders to determine the set of texels that would be accessed by an equivalent filtered texture lookup.

Instead of returning a filtered texture value, the instruction returns a structure that can be interpreted by shader code to determine the footprint of a filtered texture lookup. This structure includes integer values that identify a small neighborhood of texels in the image being accessed and a bitfield that indicates which texels in that neighborhood would be used. The structure also includes a bitfield where each bit identifies whether any texel in a small aligned block of texels would be fetched by the texture lookup. The size of each block is specified by an access granularity provided by the shader. The minimum granularity supported by this extension is 2x2 (for 2D textures) and 2x2x2 (for 3D textures); the maximum granularity is 256x256 (for 2D textures) or 64x32x32 (for 3D textures). Each footprint query returns the footprint from a single texture level. When using minification filters that combine accesses from multiple mipmap levels, shaders must perform separate queries for the two levels accessed (“fine” and “coarse”). The footprint query also returns a flag indicating if the texture lookup would access texels from only one mipmap level or from two neighboring levels.

This extension should be useful for multi-pass rendering operations that do an initial expensive rendering pass to produce a first image that is then used as a texture for a second pass. If the second pass ends up accessing only portions of the first image (e.g., due to visbility), the work spent rendering the non-accessed portion of the first image was wasted. With this feature, an application can limit this waste using an initial pass over the geometry in the second image that performs a footprint query for each visible pixel to determine the set of pixels that it needs from the first image. This pass would accumulate an aggregate footprint of all visible pixels into a separate “footprint image” using shader atomics. Then, when rendering the first image, the application can kill all shading work for pixels not in this aggregate footprint.

This extension has a number of limitations. The `OpImageSampleFootprintNV` instruction only supports for two- and three-dimensional textures. Footprint evaluation only supports the CLAMP_TO_EDGE wrap mode; results are undefined for all other wrap modes. Only a limited set of granularity values and that set does not support separate coverage information for each texel in the original image.

When using SPIR-V generated from the OpenGL Shading Language, the new instruction will be generated from code using the new `textureFootprint`*NV built-in functions from the `GL_NV_shader_texture_footprint` shading language extension.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_IMAGE_FOOTPRINT_FEATURES_NV`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceShaderImageFootprintFeaturesNV

#### New Functions

None.

#### New SPIR-V Capability

- ImageFootprintNV

#### Issues

(1) The footprint returned by the SPIR-V instruction is a structure that includes an anchor, an offset, and a mask that represents a 8x8 or 4x4x4 neighborhood of texel groups. But the bits of the mask are not stored in simple pitch order. Why is the footprint built this way?

RESOLVED: We expect that applications using this feature will want to use a fixed granularity and accumulate coverage information from the returned footprints into an aggregate “footprint image” that tracks the portions of an image that would be needed by regular texture filtering. If an application is using a two-dimensional image with 4x4 pixel granularity, we expect that the footprint image will use 64-bit texels where each bit in an 8x8 array of bits corresponds to coverage for a 4x4 block in the original image. Texel (0,0) in the footprint image would correspond to texels (0,0) through (31,31) in the original image.

In the usual case, the footprint for a single access will fully contained in a 32x32 aligned region of the original texture, which corresponds to a single 64-bit texel in the footprint image. In that case, the implementation will return an anchor coordinate pointing at the single footprint image texel, an offset vector of (0,0), and a mask whose bits are aligned with the bits in the footprint texel. For this case, the shader can simply atomically OR the mask bits into the contents of the footprint texel to accumulate footprint coverage.

In the worst case, the footprint for a single access spans multiple 32x32 aligned regions and may require updates to four separate footprint image texels. In this case, the implementation will return an anchor coordinate pointing at the lower right footprint image texel and an offset will identify how many “columns” and “rows” of the returned 8x8 mask correspond to footprint texels to the left and above the anchor texel. If the anchor is (2,3), the 64 bits of the returned mask are arranged spatially as follows, where each 4x4 block is assigned a bit number that matches its bit number in the footprint image texels:

        +-------------------------+-------------------------+
        | -- -- -- -- -- -- -- -- | -- -- -- -- -- -- -- -- |
        | -- -- -- -- -- -- -- -- | -- -- -- -- -- -- -- -- |
        | -- -- -- -- -- -- -- -- | -- -- -- -- -- -- -- -- |
        | -- -- -- -- -- -- -- -- | -- -- -- -- -- -- -- -- |
        | -- -- -- -- -- -- -- -- | -- -- -- -- -- -- -- -- |
        | -- -- -- -- -- -- 46 47 | 40 41 42 43 44 45 -- -- |
        | -- -- -- -- -- -- 54 55 | 48 49 50 51 52 53 -- -- |
        | -- -- -- -- -- -- 62 63 | 56 57 58 59 60 61 -- -- |
        +-------------------------+-------------------------+
        | -- -- -- -- -- -- 06 07 | 00 01 02 03 04 05 -- -- |
        | -- -- -- -- -- -- 14 15 | 08 09 10 11 12 13 -- -- |
        | -- -- -- -- -- -- 22 23 | 16 17 18 19 20 21 -- -- |
        | -- -- -- -- -- -- 30 31 | 24 25 26 27 28 29 -- -- |
        | -- -- -- -- -- -- 38 39 | 32 33 34 35 36 37 -- -- |
        | -- -- -- -- -- -- -- -- | -- -- -- -- -- -- -- -- |
        | -- -- -- -- -- -- -- -- | -- -- -- -- -- -- -- -- |
        | -- -- -- -- -- -- -- -- | -- -- -- -- -- -- -- -- |
        +-------------------------+-------------------------+

To accumulate coverage for each of the four footprint image texels, a shader can AND the returned mask with simple masks derived from the x and y offset values and then atomically OR the updated mask bits into the contents of the corresponding footprint texel.

        uint64_t returnedMask = (uint64_t(footprint.mask.x) | (uint64_t(footprint.mask.y) << 32));
        uint64_t rightMask    = ((0xFF >> footprint.offset.x) * 0x0101010101010101UL);
        uint64_t bottomMask   = 0xFFFFFFFFFFFFFFFFUL >> (8 * footprint.offset.y);
        uint64_t bottomRight  = returnedMask & bottomMask & rightMask;
        uint64_t bottomLeft   = returnedMask & bottomMask & (~rightMask);
        uint64_t topRight     = returnedMask & (~bottomMask) & rightMask;
        uint64_t topLeft      = returnedMask & (~bottomMask) & (~rightMask);

(2) What should an application do to ensure maximum performance when accumulating footprints into an aggregate footprint image?

RESOLVED: We expect that the most common usage of this feature will be to accumulate aggregate footprint coverage, as described in the previous issue. Even if you ignore the anisotropic filtering case where the implementation may return a granularity larger than that requested by the caller, each shader invocation will need to use atomic functions to update up to four footprint image texels for each level of detail accessed. Having each active shader invocation perform multiple atomic operations can be expensive, particularly when neighboring invocations will want to update the same footprint image texels.

Techniques can be used to reduce the number of atomic operations performed when accumulating coverage include:

- Have logic that detects returned footprints where all components of the returned offset vector are zero. In that case, the mask returned by the footprint function is guaranteed to be aligned with the footprint image texels and affects only a single footprint image texel.

- Have fragment shaders communicate using built-in functions from the `VK_NV_shader_subgroup_partitioned` extension or other shader subgroup extensions. If you have multiple invocations in a subgroup that need to update the same texel (x,y) in the footprint image, compute an aggregate footprint mask across all invocations in the subgroup updating that texel and have a single invocation perform an atomic operation using that aggregate mask.

- When the returned footprint spans multiple texels in the footprint image, each invocation need to perform four atomic operations. In the previous issue, we had an example that computed separate masks for “topLeft”, “topRight”, “bottomLeft”, and “bottomRight”. When the invocations in a subgroup have good locality, it might be the case the “top left” for some invocations might refer to footprint image texel (10,10), while neighbors might have their “top left” texels at (11,10), (10,11), and (11,11). If you compute separate masks for even/odd x and y values instead of left/right or top/bottom, the “odd/odd” mask for all invocations in the subgroup hold coverage for footprint image texel (11,11), which can be updated by a single atomic operation for the entire subgroup.

#### Examples

TBD

#### Version History

- Revision 2, 2018-09-13 (Pat Brown)

  - Add issue (2) with performance tips.

- Revision 1, 2018-08-12 (Pat Brown)

  - Initial draft

#### VK_NV_shader_sm_builtins

Name String

  `VK_NV_shader_sm_builtins`

Extension Type

  Device extension

Registered Extension Number

  155

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.1

Contact

  - Daniel Koch dgkoch

Last Modified Date

  2019-05-28

Interactions and External Dependencies

  - This extension requires `SPV_NV_shader_sm_builtins`.

  - This extension enables `GL_NV_shader_sm_builtins` for GLSL source languages.

Contributors

  - Jeff Bolz, NVIDIA

  - Eric Werness, NVIDIA

#### Description

This extension provides the ability to determine device-specific properties on NVIDIA GPUs. It provides the number of streaming multiprocessors (SMs), the maximum number of warps (subgroups) that can run on an SM, and shader builtins to enable invocations to identify which SM and warp a shader invocation is executing on.

This extension enables support for the SPIR-V `ShaderSMBuiltinsNV` capability.

These properties and built-ins should typically only be used for debugging purposes.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_SM_BUILTINS_FEATURES_NV`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_SM_BUILTINS_PROPERTIES_NV`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceShaderSMBuiltinsFeaturesNV

- VkPhysicalDeviceShaderSMBuiltinsPropertiesNV

#### New Functions

None.

#### New or Modified Built-In Variables

- `WarpsPerSMNV`

- `SMCountNV`

- `WarpIDNV`

- `SMIDNV`

#### New SPIR-V Capabilities

- `ShaderSMBuiltinsNV`

#### Issues

1. What should we call this extension?

   RESOLVED: Using NV_shader_sm_builtins. Other options considered included:

   - NV_shader_smid - but SMID is really easy to typo/confuse as SIMD.

   - NV_shader_sm_info - but Info is typically reserved for input structures

#### Version History

- Revision 1, 2019-05-28 (Daniel Koch)

  - Internal revisions

#### VK_NV_shader_subgroup_partitioned

Name String

  `VK_NV_shader_subgroup_partitioned`

Extension Type

  Device extension

Registered Extension Number

  199

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.1

Contact

  - Jeff Bolz jeffbolznv

Last Modified Date

  2018-03-17

Contributors

  - Jeff Bolz, NVIDIA

This extension enables support for a new class of group operations on subgroups via the `GL_NV_shader_subgroup_partitioned` GLSL extension and `SPV_NV_shader_subgroup_partitioned` SPIR-V extension. Support for these new operations is advertised via the `VK_SUBGROUP_FEATURE_PARTITIONED_BIT_NV` bit.

This extension requires Vulkan 1.1, for general subgroup support.

#### New Object Types

None.

#### New Enum Constants

- Extending VkSubgroupFeatureFlagBits:

  - `VK_SUBGROUP_FEATURE_PARTITIONED_BIT_NV`

#### New Enums

None.

#### New Structures

None.

#### New Functions

None.

#### Issues

None.

#### Version History

- Revision 1, 2018-03-17 (Jeff Bolz)

  - Internal revisions

#### VK_NV_shading_rate_image

Name String

  `VK_NV_shading_rate_image`

Extension Type

  Device extension

Registered Extension Number

  165

Revision

  3

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Contact

  - Pat Brown nvpbrown

Last Modified Date

  2019-07-18

Contributors

  - Pat Brown, NVIDIA

  - Carsten Rohde, NVIDIA

  - Jeff Bolz, NVIDIA

  - Daniel Koch, NVIDIA

  - Mathias Schott, NVIDIA

  - Matthew Netsch, Qualcomm Technologies, Inc.

This extension allows applications to use a variable shading rate when processing fragments of rasterized primitives. By default, Vulkan will spawn one fragment shader for each pixel covered by a primitive. In this extension, applications can bind a shading rate image that can be used to vary the number of fragment shader invocations across the framebuffer. Some portions of the screen may be configured to spawn up to 16 fragment shaders for each pixel, while other portions may use a single fragment shader invocation for a 4x4 block of pixels. This can be useful for use cases like eye tracking, where the portion of the framebuffer that the user is looking at directly can be processed at high frequency, while distant corners of the image can be processed at lower frequency. Each texel in the shading rate image represents a fixed-size rectangle in the framebuffer, covering 16x16 pixels in the initial implementation of this extension. When rasterizing a primitive covering one of these rectangles, the Vulkan implementation reads a texel in the bound shading rate image and looks up the fetched value in a palette to determine a base shading rate.

In addition to the API support controlling rasterization, this extension also adds Vulkan support for the `SPV_NV_shading_rate` extension to SPIR-V. That extension provides two fragment shader variable decorations that allow fragment shaders to determine the shading rate used for processing the fragment:

- `FragmentSizeNV`, which indicates the width and height of the set of pixels processed by the fragment shader.

- `InvocationsPerPixel`, which indicates the maximum number of fragment shader invocations that could be spawned for the pixel(s) covered by the fragment.

When using SPIR-V in conjunction with the OpenGL Shading Language (GLSL), the fragment shader capabilities are provided by the `GL_NV_shading_rate_image` language extension and correspond to the built-in variables `gl_FragmentSizeNV` and `gl_InvocationsPerPixelNV`, respectively.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_SHADING_RATE_IMAGE_STATE_CREATE_INFO_NV`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADING_RATE_IMAGE_FEATURES_NV`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADING_RATE_IMAGE_PROPERTIES_NV`

  - `VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_COARSE_SAMPLE_ORDER_STATE_CREATE_INFO_NV`

- Extending VkImageLayout:

  - `VK_IMAGE_LAYOUT_SHADING_RATE_OPTIMAL_NV`

- Extending VkDynamicState:

  - `VK_DYNAMIC_STATE_VIEWPORT_SHADING_RATE_PALETTE_NV`

  - `VK_DYNAMIC_STATE_VIEWPORT_COARSE_SAMPLE_ORDER_NV`

- Extending VkAccessFlagBits:

  - `VK_ACCESS_SHADING_RATE_IMAGE_READ_BIT_NV`

- Extending VkImageUsageFlagBits:

  - `VK_IMAGE_USAGE_SHADING_RATE_IMAGE_BIT_NV`

- Extending VkPipelineStageFlagBits

  - `VK_PIPELINE_STAGE_SHADING_RATE_IMAGE_BIT_NV`

#### New Enums

- VkShadingRatePaletteEntryNV, containing the following constants:

  - `VK_SHADING_RATE_PALETTE_ENTRY_NO_INVOCATIONS_NV`

  - `VK_SHADING_RATE_PALETTE_ENTRY_16_INVOCATIONS_PER_PIXEL_NV`

  - `VK_SHADING_RATE_PALETTE_ENTRY_8_INVOCATIONS_PER_PIXEL_NV`

  - `VK_SHADING_RATE_PALETTE_ENTRY_4_INVOCATIONS_PER_PIXEL_NV`

  - `VK_SHADING_RATE_PALETTE_ENTRY_2_INVOCATIONS_PER_PIXEL_NV`

  - `VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_PIXEL_NV`

  - `VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_2X1_PIXELS_NV`

  - `VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_1X2_PIXELS_NV`

  - `VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_2X2_PIXELS_NV`

  - `VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_4X2_PIXELS_NV`

  - `VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_2X4_PIXELS_NV`

  - `VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_4X4_PIXELS_NV`

- VkCoarseSampleOrderTypeNV, containing the following constants:

  - `VK_COARSE_SAMPLE_ORDER_TYPE_DEFAULT_NV`

  - `VK_COARSE_SAMPLE_ORDER_TYPE_CUSTOM_NV`

  - `VK_COARSE_SAMPLE_ORDER_TYPE_PIXEL_MAJOR_NV`

  - `VK_COARSE_SAMPLE_ORDER_TYPE_SAMPLE_MAJOR_NV`

#### New Structures

- VkShadingRatePaletteNV

- VkPipelineViewportShadingRateImageStateCreateInfoNV

- VkPhysicalDeviceShadingRateImageFeaturesNV

- VkPhysicalDeviceShadingRateImagePropertiesNV

- VkCoarseSampleLocationNV

- VkCoarseSampleOrderCustomNV

- VkPipelineViewportCoarseSampleOrderStateCreateInfoNV

#### New Functions

- vkCmdBindShadingRateImageNV

- vkCmdSetViewportShadingRatePaletteNV

- vkCmdSetCoarseSampleOrderNV

#### Issues

(1) When using shading rates specifying “coarse” fragments covering multiple pixels, we will generate a combined coverage mask that combines the coverage masks of all pixels covered by the fragment. By default, these masks are combined in an implementation-dependent order. Should we provide a mechanism allowing applications to query or specify an exact order?

RESOLVED: Yes, this feature is useful for cases where most of the fragment shader can be evaluated once for an entire coarse fragment, but where some per-pixel computations are also required. For example, a per-pixel alpha test may want to kill all the samples for some pixels in a coarse fragment. This sort of test can be implemented using an output sample mask, but such a shader would need to know which bit in the mask corresponds to each sample in the coarse fragment. We are including a mechanism to allow aplications to specify the orders of coverage samples for each shading rate and sample count, either as static pipeline state or dynamically via a command buffer. This portion of the extension has its own feature bit.

We will not be providing a query to determine the implementation-dependent default ordering. The thinking here is that if an application cares enough about the coarse fragment sample ordering to perform such a query, it could instead just set its own order, also using custom per-pixel sample locations if required.

(2) For the pipeline stage `VK_PIPELINE_STAGE_SHADING_RATE_IMAGE_BIT_NV`, should we specify a precise location in the pipeline the shading rate image is accessed (after geometry shading, but before the early fragment tests) or leave it under-specified in case there are other implementations that access the image in a different pipeline location?

RESOLVED We are specifying the pipeline stage to be between the final stage used for vertex processing (`VK_PIPELINE_STAGE_GEOMETRY_SHADER_BIT`) and before the first stage used for fragment processing (`VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT`), which seems to be the natural place to access the shading rate image.

(3) How do centroid-sampled variables work with fragments larger than one pixel?

RESOLVED For single-pixel fragments, fragment shader inputs decorated with `Centroid` are sampled at an implementation-dependent location in the intersection of the area of the primitive being rasterized and the area of the pixel that corresponds to the fragment. With multi-pixel fragments, we follow a similar pattern, using the intersection of the primitive and the set of pixels corresponding to the fragment.

One important thing to keep in mind when using such “coarse” shading rates is that fragment attributes are sampled at the center of the fragment by default, regardless of the set of pixels/samples covered by the fragment. For fragments with a size of 4x4 pixels, this center location will be more than two pixels (1.5 * sqrt(2)) away from the center of the pixels at the corners of the fragment. When rendering a primitive that covers only a small part of a coarse fragment, sampling a color outside the primitive can produce overly bright or dark color values if the color values have a large gradient. To deal with this, an application can use centroid sampling on attributes where “extrapolation” artifacts can lead to overly bright or dark pixels. Note that this same problem also exists for multisampling with single-pixel fragments, but is less severe because it only affects certain samples of a pixel and such bright/dark samples may be averaged with other samples that don’t have a similar problem.

#### Version History

- Revision 3, 2019-07-18 (Mathias Schott)

  - Fully list extension interfaces in this appendix.

- Revision 2, 2018-09-13 (Pat Brown)

  - Miscellaneous edits preparing the specification for publication.

- Revision 1, 2018-08-08 (Pat Brown)

  - Internal revisions

#### VK_NV_viewport_array2

Name String

  `VK_NV_viewport_array2`

Extension Type

  Device extension

Registered Extension Number

  97

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Daniel Koch dgkoch

Last Modified Date

  2017-02-15

Interactions and External Dependencies

  - This extension requires the `SPV_NV_viewport_array2` SPIR-V extension.

  - This extension requires the `GL_NV_viewport_array2` extension for GLSL source languages.

  - This extension requires the `geometryShader` and `multiViewport` features.

  - This extension interacts with the `tessellationShader` feature.

Contributors

  - Piers Daniell, NVIDIA

  - Jeff Bolz, NVIDIA

This extension adds support for the following SPIR-V extension in Vulkan:

- `SPV_NV_viewport_array2`

which allows a single primitive to be broadcast to multiple viewports and/or multiple layers. A new shader built-in output `ViewportMaskNV` is provided, which allows a single primitive to be output to multiple viewports simultaneously. Also, a new SPIR-V decoration is added to control whether the effective viewport index is added into the variable decorated with the `Layer` built-in decoration. These capabilities allow a single primitive to be output to multiple layers simultaneously.

This extension allows variables decorated with the `Layer` and `ViewportIndex` built-ins to be exported from vertex or tessellation shaders, using the `ShaderViewportIndexLayerNV` capability.

This extension adds a new `ViewportMaskNV` built-in decoration that is available for output variables in vertex, tessellation evaluation, and geometry shaders, and a new `ViewportRelativeNV` decoration that can be added on variables decorated with `Layer` when using the `ShaderViewportMaskNV` capability.

When using GLSL source-based shading languages, the `gl_ViewportMask`[] built-in output variable and `viewport_relative` layout qualifier from `GL_NV_viewport_array2` map to the `ViewportMaskNV` and `ViewportRelativeNV` decorations, respectively. Behaviour is described in the `GL_NV_viewport_array2` extension specificiation.

| Note The `ShaderViewportIndexLayerNV` capability is equivalent to the `ShaderViewportIndexLayerEXT` capability added by `VK_EXT_shader_viewport_index_layer`.

#### New Object Types

None.

#### New Enum Constants

None.

#### New Enums

None.

#### New Structures

None.

#### New Functions

None.

#### New or Modified Built-In Variables

- (modified) `Layer`

- (modified) `ViewportIndex`

- `ViewportMaskNV`

#### New Variable Decoration

- `ViewportRelativeNV` in `Layer`

#### New SPIR-V Capabilities

- `ShaderViewportIndexLayerNV`

- `ShaderViewportMaskNV`

#### Issues

None yet!

#### Version History

- Revision 1, 2017-02-15 (Daniel Koch)

  - Internal revisions

#### VK_NV_viewport_swizzle

Name String

  `VK_NV_viewport_swizzle`

Extension Type

  Device extension

Registered Extension Number

  99

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Piers Daniell pdaniell-nv

Last Modified Date

  2016-12-22

Interactions and External Dependencies

  - This extension requires `multiViewport` and `geometryShader` features to be useful.

Contributors

  - Daniel Koch, NVIDIA

  - Jeff Bolz, NVIDIA

This extension provides a new per-viewport swizzle that can modify the position of primitives sent to each viewport. New viewport swizzle state is added for each viewport, and a new position vector is computed for each vertex by selecting from and optionally negating any of the four components of the original position vector.

This new viewport swizzle is useful for a number of algorithms, including single-pass cubemap rendering (broadcasting a primitive to multiple faces and reorienting the vertex position for each face) and voxel rasterization. The per-viewport component remapping and negation provided by the swizzle allows application code to re-orient three-dimensional geometry with a view along any of the X, Y, or Z axes. If a perspective projection and depth buffering is required, 1/W buffering should be used, as described in the single-pass cubemap rendering example in the “Issues” section below.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PIPELINE_VIEWPORT_SWIZZLE_STATE_CREATE_INFO_NV`

#### New Enums

- VkViewportCoordinateSwizzleNV

- VkPipelineViewportSwizzleStateCreateFlagsNV

#### New Structures

- VkViewportSwizzleNV

- VkPipelineViewportSwizzleStateCreateInfoNV

#### New Functions

None.

#### Issues

1) Where does viewport swizzling occur in the pipeline?

RESOLVED: Despite being associated with the viewport, viewport swizzling must happen prior to the viewport transform. In particular, it needs to be performed before clipping and perspective division.

The viewport mask expansion (`VK_NV_viewport_array2`) and the viewport swizzle could potentially be performed before or after transform feedback, but feeding back several viewports worth of primitives with different swizzles doesn’t seem particularly useful. This specification applies the viewport mask and swizzle after transform feedback, and makes primitive queries only count each primitive once.

2) Any interesting examples of how this extension, `VK_NV_viewport_array2`, and `VK_NV_geometry_shader_passthrough` can be used together in practice?

RESOLVED: One interesting use case for this extension is for single-pass rendering to a cubemap. In this example, the application would attach a cubemap texture to a layered FBO where the six cube faces are treated as layers. Vertices are sent through the vertex shader without applying a projection matrix, where the `gl_Position` output is (x,y,z,1) and the center of the cubemap is at (0,0,0). With unextended Vulkan, one could have a conventional instanced geometry shader that looks something like the following:

    layout(invocations = 6) in;     // separate invocation per face
    layout(triangles) in;
    layout(triangle_strip) out;
    layout(max_vertices = 3) out;

    in Inputs {
    vec2 texcoord;
    vec3 normal;
    vec4 baseColor;
    } v[];

        out Outputs {
        vec2 texcoord;
        vec3 normal;
        vec4 baseColor;
        };

        void main()
        {
        int face = gl_InvocationID;  // which face am I?

        // Project gl_Position for each vertex onto the cube map face.
        vec4 positions[3];
        for (int i = 0; i < 3; i++) {
            positions[i] = rotate(gl_in[i].gl_Position, face);
        }

        // If the primitive doesn't project onto this face, we're done.
        if (shouldCull(positions)) {
            return;
        }

        // Otherwise, emit a copy of the input primitive to the
        // appropriate face (using gl_Layer).
        for (int i = 0; i < 3; i++) {
            gl_Layer = face;
            gl_Position = positions[i];
            texcoord = v[i].texcoord;
            normal = v[i].normal;
            baseColor = v[i].baseColor;
            EmitVertex();
        }
    }

With passthrough geometry shaders, this can be done using a much simpler shader:

    layout(triangles) in;
    layout(passthrough) in Inputs {
        vec2 texcoord;
        vec3 normal;
        vec4 baseColor;
    }
    layout(passthrough) in gl_PerVertex {
        vec4 gl_Position;
    } gl_in[];
    layout(viewport_relative) out int gl_Layer;

    void main()
    {
        // Figure out which faces the primitive projects onto and
        // generate a corresponding viewport mask.
        uint mask = 0;
        for (int i = 0; i < 6; i++) {
            if (!shouldCull(face)) {
            mask |= 1U << i;
            }
        }
        gl_ViewportMask = mask;
        gl_Layer = 0;
    }

The application code is set up so that each of the six cube faces has a separate viewport (numbered 0 to 5). Each face also has a separate swizzle, programmed via the VkPipelineViewportSwizzleStateCreateInfoNV pipeline state. The viewport swizzle feature performs the coordinate transformation handled by the `rotate`() function in the original shader. The `viewport_relative` layout qualifier says that the viewport number (0 to 5) is added to the base `gl_Layer` value of 0 to determine which layer (cube face) the primitive should be sent to.

Note that the use of the passed through input `normal` in this example suggests that the fragment shader in this example would perform an operation like per-fragment lighting. The viewport swizzle would transform the position to be face-relative, but `normal` would remain in the original coordinate system. It seems likely that the fragment shader in either version of the example would want to perform lighting in the original coordinate system. It would likely do this by reconstructing the position of the fragment in the original coordinate system using `gl_FragCoord`, a constant or uniform holding the size of the cube face, and the input `gl_ViewportIndex` (or `gl_Layer`), which identifies the cube face. Since the value of `normal` is in the original coordinate system, it would not need to be modified as part of this coordinate transformation.

Note that while the `rotate`() operation in the regular geometry shader above could include an arbitrary post-rotation projection matrix, the viewport swizzle does not support arbitrary math. To get proper projection, 1/W buffering should be used. To do this:

1. Program the viewport swizzles to move the pre-projection W eye coordinate (typically 1.0) into the Z coordinate of the swizzle output and the eye coordinate component used for depth into the W coordinate. For example, the viewport corresponding to the +Z face might use a swizzle of (+X, -Y, +W, +Z). The Z normalized device coordinate computed after swizzling would then be z'/w' = 1/Zeye.

2. On NVIDIA implementations supporting floating-point depth buffers with values outside [0,1], prevent unwanted near plane clipping by enabling `depthClampEnable`. Ensure that the depth clamp doesn’t mess up depth testing by programming the depth range to very large values, such as `minDepthBounds`=-z, `maxDepthBounds`=+z, where z = 2127. It should be possible to use IEEE infinity encodings also (`0xFF800000` for `-INF`, `0x7F800000` for `+INF`). Even when near/far clipping is disabled, primitives extending behind the eye will still be clipped because one or more vertices will have a negative W coordinate and fail X/Y clipping tests.

   On other implementations, scale X, Y, and Z eye coordinates so that vertices on the near plane have a post-swizzle W coordinate of 1.0. For example, if the near plane is at Zeye = 1/256, scale X, Y, and Z by 256.

3. Adjust depth testing to reflect the fact that 1/W values are large near the eye and small away from the eye. Clear the depth buffer to zero (infinitely far away) and use a depth test of `VK_COMPARE_OP_GREATER` instead of `VK_COMPARE_OP_LESS`.

#### Version History

- Revision 1, 2016-12-22 (Piers Daniell)

  - Internal revisions

#### VK_NVX_image_view_handle

Name String

  `VK_NVX_image_view_handle`

Extension Type

  Device extension

Registered Extension Number

  31

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Contact

  - Eric Werness ewerness

Last Modified Date

  2018-12-07

Contributors

  - Eric Werness, NVIDIA

  - Jeff Bolz, NVIDIA

  - Daniel Koch, NVIDIA

This extension allows applications to query an opaque handle from an image view for use as a sampled image or storage image. This provides no direct functionality itself.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_IMAGE_VIEW_HANDLE_INFO_NVX`

#### New Enums

None.

#### New Structures

- VkImageViewHandleInfoNVX

#### New Functions

- vkGetImageViewHandleNVX

#### Issues

None.

#### Version History

- Revision 1, 2018-12-07 (Eric Werness)

  - Internal revisions

#### VK_NVX_multiview_per_view_attributes

Name String

  `VK_NVX_multiview_per_view_attributes`

Extension Type

  Device extension

Registered Extension Number

  98

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_multiview`

Contact

  - Jeff Bolz jeffbolznv

Last Modified Date

  2017-01-13

IP Status

  No known IP claims.

Interactions and External Dependencies

  - This extension requires the `SPV_NVX_multiview_per_view_attributes` SPIR-V extension.

  - This extension requires the `GL_NVX_multiview_per_view_attributes` extension for GLSL source languages.

  - This extension interacts with `VK_NV_viewport_array2`.

Contributors

  - Jeff Bolz, NVIDIA

  - Daniel Koch, NVIDIA

This extension adds a new way to write shaders to be used with multiview subpasses, where the attributes for all views are written out by a single invocation of the vertex processing stages. Related SPIR-V and GLSL extensions `SPV_NVX_multiview_per_view_attributes` and `GL_NVX_multiview_per_view_attributes` introduce per-view position and viewport mask attributes arrays, and this extension defines how those per-view attribute arrays are interpreted by Vulkan. Pipelines using per-view attributes may only execute the vertex processing stages once for all views rather than once per-view, which reduces redundant shading work.

A subpass creation flag controls whether the subpass uses this extension. A subpass must either exclusively use this extension or not use it at all.

Some Vulkan implementations only support the position attribute varying between views in the X component. A subpass can declare via a second creation flag whether all pipelines compiled for this subpass will obey this restriction.

Shaders that use the new per-view outputs (e.g. `gl_PositionPerViewNV`) must also write the non-per-view output (`gl_Position`), and the values written must be such that `gl_Position = gl_PositionPerViewNV[gl_ViewIndex]` for all views in the subpass. Implementations are free to either use the per-view outputs or the non-per-view outputs, whichever would be more efficient.

If `VK_NV_viewport_array2` is not also supported and enabled, the per-view viewport mask must not be used.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_PER_VIEW_ATTRIBUTES_PROPERTIES_NVX`

- Extending VkSubpassDescriptionFlagBits

  - `VK_SUBPASS_DESCRIPTION_PER_VIEW_ATTRIBUTES_BIT_NVX`

  - `VK_SUBPASS_DESCRIPTION_PER_VIEW_POSITION_X_ONLY_BIT_NVX`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceMultiviewPerViewAttributesPropertiesNVX

#### New Functions

None.

#### New Built-In Variables

- `PositionPerViewNV`

- `ViewportMaskPerViewNV`

#### New SPIR-V Capabilities

- `PerViewAttributesNV`

#### Issues

None.

#### Examples

    #version 450 core

    #extension GL_KHX_multiview : enable
    #extension GL_NVX_multiview_per_view_attributes : enable

    layout(location = 0) in vec4 position;
    layout(set = 0, binding = 0) uniform Block { mat4 mvpPerView[2]; } buf;

    void main()
    {
        // Output both per-view positions and gl_Position as a function
        // of gl_ViewIndex
        gl_PositionPerViewNV[0] = buf.mvpPerView[0] * position;
        gl_PositionPerViewNV[1] = buf.mvpPerView[1] * position;
        gl_Position = buf.mvpPerView[gl_ViewIndex] * position;
    }

#### Version History

- Revision 1, 2017-01-13 (Jeff Bolz)

  - Internal revisions

#### VK_QCOM_render_pass_transform

Name String

  `VK_QCOM_render_pass_transform`

Extension Type

  Device extension

Registered Extension Number

  283

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_swapchain`

  - Requires `VK_KHR_surface`

Contact

  - Jeff Leger jackohound

Last Modified Date

  2020-02-05

Interactions and External Dependencies

  - This extension requires VK_KHR_swapchain

  - This extension interacts with VK_EXT_fragment_density_map

Contributors

  - Jeff Leger, Qualcomm Technologies, Inc.

  - Brandon Light, Qualcomm Technologies, Inc.

This extension provides a mechanism for applications to enable driver support for render pass transform.

Mobile devices can be rotated and mobile applications need to render properly when a device is held in a landscape or portrait orientation. When the current orientation differs from the device’s native orientation, a rotation is required so that the "up" direction of the rendered scene matches the current orientation.

If the Display Processing Unit (DPU) doesnt natively support rotation, the Vulkan presentation engine can handle this rotation in a separate composition pass. Alternatively, the application can render frames "pre-rotated" to avoid this extra pass. The latter is preferred to reduce power consumption and achieve the best performance because it avoids tasking the GPU with extra work to perform the copy/rotate operation.

Unlike OpenGL ES, the burden of pre-rotation in Vulkan falls on the application. To implement pre-rotation, applications render into swapchain images matching the device native aspect ratio of the display and "pre-rotate" the rendering content to match the device’s current orientation. The burden is more than adjusting the Model View Projection (MVP) matrix in the vertex shader to account for rotation and aspect ratio. The coordinate systems of scissors, viewports, derivatives and several shader built-ins may need to be adapted to produce the correct result.

It is difficult for some game engines to manage this burden; many chose to simply accept the performance/power overhead of performing rotation in the presentation engine.

This extension allows applications to achieve the performance benefits of pre-rotated rendering by moving much of the above-mentioned burden to the graphics driver. The following is unchanged with this extension:

- Applications create a swapchain matching the native orientation of the display. Applications must also set the VkSwapchainCreateInfoKHR::`preTransform` equal to the `currentTransform` as returned by vkGetPhysicalDeviceSurfaceCapabilitiesKHR.

The following is changed with this extension:

- At vkCmdBeginRenderpass, the application provides extension struct VkRenderPassTransformBeginInfoQCOM specifying the render pass transform parameters.

- At vkBeginCommandBuffer for secondary command buffers, the application provides extension struct VkCommandBufferInheritanceRenderPassTransformInfoQCOM specifying the render pass transform parameters.

- The `renderArea`, viewPorts and scissors are all provided in the current (non-rotated) coordinate system. The implementation will transform those into the native (rotated) coordinate system.

- The implementation is responsible for transforming shader built-ins (`FragCoord`, `PointCoord`, `SamplePosition`, interpolateAt(), dFdx, dFdy, fWidth) into the rotated coordinate system.

- The implementation is responsible for transforming `position` to the rotated coordinate system.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_COMMAND_BUFFER_INHERITANCE_RENDER_PASS_TRANSFORM_INFO_QCOM`

  - `VK_STRUCTURE_TYPE_RENDER_PASS_TRANSFORM_BEGIN_INFO_QCOM`

- Extending VkRenderPassCreateFlagBits:

  - `VK_RENDER_PASS_CREATE_TRANSFORM_BIT_QCOM`

#### New Enums

None.

#### New Structures

- VkRenderPassTransformBeginInfoQCOM

- VkCommandBufferInheritanceRenderPassTransformInfoQCOM

#### New Functions

None.

#### Issues

1) Should the extension support only rotations (e.g. 90, 180, 270-degrees), or also mirror transforms (e.g. vertical flips)? Mobile use-cases only require rotation. Other display systems such as projectors might require a flipped transform.

RESOLVED: In this version of the extension, the functionality is restricted to 90, 180, and 270-degree rotations to address mobile use-cases.

2) How does this extension interact with VK_EXT_fragment_density_map?

RESOLVED Some implementations may not be able to support a render pass that enables both renderpass transform and fragment density maps. For simplicity, this extension disallows enabling both features within a single render pass.

3) What should this extension be named?

We considered names such as "rotated_rendering", "pre_rotation" and others. Since the functionality is limited to a render pass, it seemed the name should include "render_pass". While the current extension is limited to rotations, it could be extended to other transforms (like mirror) in the future.

RESOLVED The name "render_pass_transform" seems like the most accurate description of the introduced functionality.

#### Version History

- Revision 1, 2020-02-05 (Jeff Leger)

### List of Provisional Extensions

- `VK_KHR_deferred_host_operations`

- `VK_KHR_pipeline_library`

- `VK_KHR_ray_tracing`

#### VK_KHR_deferred_host_operations

Name String

  `VK_KHR_deferred_host_operations`

Extension Type

  Device extension

Registered Extension Number

  269

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - This is a provisional extension and must be used with caution. See the description of provisional header files for enablement and stability details.

Contact

  - Josh Barczak jbarczak

Last Modified Date

  2020-03-06

IP Status

  No known IP claims.

Contributors

  - Joshua Barczak, Intel

  - Jeff Bolz, NVIDIA

  - Daniel Koch, NVIDIA

  - Slawek Grajewski, Intel

  - Tobias Hector, AMD

  - Yuriy O’Donnell, Epic

  - Eric Werness, NVIDIA

  - Baldur Karlsson, Valve

  - Jesse Barker, Unity

  - Contributors to VK_KHR_ray_tracing

The VK_KHR_deferred_host_operations extension defines the infrastructure and usage patterns for deferrable commands, but does not specify any commands as deferrable. This is left to additional dependent extensions. Commands must not be deferred unless the deferral is specifically allowed by another extension which depends on VK_KHR_deferred_host_operations.

#### New Object Types

- VkDeferredOperationKHR

#### New Enum Constants

- Extending VkResult:

  - `VK_THREAD_IDLE_KHR`

  - `VK_THREAD_DONE_KHR`

  - `VK_OPERATION_DEFERRED_KHR`

  - `VK_OPERATION_NOT_DEFERRED_KHR`

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_DEFERRED_OPERATION_INFO_KHR`

- Extending VkObjectType:

  - `VK_OBJECT_TYPE_DEFERRED_OPERATION_KHR`

#### New Enums

None

#### New Structures

- VkDeferredOperationInfoKHR

#### New Functions

- vkCreateDeferredOperationKHR

- vkDestroyDeferredOperationKHR

- vkGetDeferredOperationMaxConcurrencyKHR

- vkGetDeferredOperationResultKHR

- vkDeferredOperationJoinKHR

#### Code Examples

The following examples will illustrate the concept of deferrable operations using a hypothetical example. The command `vkDoSomethingExpensiveEXT` denotes a deferrable command. The structure `VkExpensiveOperationArgsEXT` represents the arguments which it would normally accept.

The following example illustrates how a vulkan application might request deferral of an expensive operation:

    // create a deferred operation
    VkDeferredOperationKHR hOp;
    VkResult result = vkCreateDeferredOperationKHR(device, pCallbacks, &hOp);
    assert(result == VK_SUCCESS);

    // initialize deferral structure
    VkDeferredOperationInfoKHR deferral;
    deferral.sType      = VK_STRUCTURE_TYPE_DEFERRED_OPERATION_INFO_KHR;
    deferral.pNext      = nullptr;
    deferral.operationHandle = hOp;

    VkExpensiveOperationArgsEXT kArgs;
    //
    // ... intialize kArgs as normal ...
    //
    kArgs.pNext = &deferral;

    result = vkDoSomethingExpensive(&kArgs);
    assert( result == VK_OPERATION_DEFERRED_KHR );

    // operation was deferred.  Execute it asynchronously
    std::async::launch(
        [ hOp ] ( )
        {
            vkDeferredOperationJoinKHR(device, hOp);

            result = vkGetDeferredOperationResultKHR(device, hOp);

            // deferred operation is now complete.  'result' indicates success or failure

            vkDestroyDeferredOperationKHR(device, hOp, pCallbacks);
        }
    );

The following example shows a subroutine which guarantees completion of a deferred operation, in the presence of multiple worker threads, and returns the result of the operation.

    VkResult FinishDeferredOperation(VkDeferredOperationKHR hOp)
    {
        // Attempt to join the operation until the implementation indicates that we should stop

        VkResult result = vkDeferredOperationJoinKHR(device, hOp);
        while( result == VK_THREAD_IDLE_KHR )
        {
            std::this_thread::yield();
            result = vkDeferredOperationJoinKHR(device, hOp);
        }

        switch( result )
        {
        case VK_SUCCESS:
            {
                // deferred operation has finished.  Query its result
                result = vkGetDeferredOperationResultKHR(device, hOp);
            }
            break;

        case VK_THREAD_DONE_KHR:
            {
                // deferred operation is being wrapped up by another thread
                //  wait for that thread to finish
                do
                {
                    std::this_thread::yield();
                    result = vkGetDeferredOperationResultKHR(device, hOp);
                } while( result == VK_NOT_READY );
            }
            break;

        default:
            assert(false); // other conditions are illegal.
            break;
        }

        return result;
    }

#### Issues

1. Should this entension have a VkPhysicalDevice*FeaturesKHR structure?

RESOLVED: No. This extension does not add any functionality on it’s own and requires a dependent extension to actually enable functionality and thus there is no value in adding a feature structure. If necessary, any dependent extension could add a feature boolean if it wanted to indicate that it is adding optional deferral support.

#### Version History

- Revision 1, 2019-12-05 (Josh Barczak, Daniel Koch)

  - Initial draft.

- Revision 2, 2020-03-06 (Daniel Koch, Tobias Hector)

  - Add missing VK_OBJECT_TYPE_DEFERRED_OPERATION_KHR enum

  - fix sample code

  - Clarified deferred operation parameter lifetimes (#2018,!3647)

#### VK_KHR_pipeline_library

Name String

  `VK_KHR_pipeline_library`

Extension Type

  Device extension

Registered Extension Number

  291

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - This is a provisional extension and must be used with caution. See the description of provisional header files for enablement and stability details.

Contact

  - Christoph Kubisch pixeljetstream

Last Modified Date

  2020-01-08

IP Status

  No known IP claims.

Contributors

  - See contributors to `VK_KHR_ray_tracing`

A pipeline library is a special pipeline that cannot be bound, instead it defines a set of shaders and shader groups which can be linked into other pipelines. The VK_KHR_pipeline_library extension defines the infrastructure for pipeline libraries, but does not specify the creation or usage of pipeline libraries. This is left to additional dependent extensions.

#### New Object Types

None

#### New Enum Constants

- Extending VkPipelineCreateFlagBits:

  - `VK_PIPELINE_CREATE_LIBRARY_BIT_KHR`

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PIPELINE_LIBRARY_CREATE_INFO_KHR`

#### New Enums

None

#### New Structures

- VkPipelineLibraryCreateInfoKHR

#### New Functions

None

#### Version History

- Revision 1, 2020-01-08 (Christoph Kubisch)

  - Initial draft.

#### VK_KHR_ray_tracing

Name String

  `VK_KHR_ray_tracing`

Extension Type

  Device extension

Registered Extension Number

  151

Revision

  8

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

  - Requires `VK_KHR_get_memory_requirements2`

  - Requires `VK_EXT_descriptor_indexing`

  - Requires `VK_KHR_buffer_device_address`

  - Requires `VK_KHR_deferred_host_operations`

  - Requires `VK_KHR_pipeline_library`

  - This is a provisional extension and must be used with caution. See the description of provisional header files for enablement and stability details.

Contact

  - Daniel Koch dgkoch

Last Modified Date

  2020-02-28

Interactions and External Dependencies

  - This extension requires the `SPV_KHR_ray_tracing` and `SPV_KHR_ray_query` SPIR-V extensions.

  - This extension requires the `GLSL_EXT_ray_tracing` and `GLSL_EXT_ray_query` extensions for GLSL source languages.

Contributors

  - Matthäus Chajdas, AMD

  - Greg Grebe, AMD

  - Nicolai Hähnle, AMD

  - Tobias Hector, AMD

  - Dave Oldcorn, AMD

  - Skyler Saleh, AMD

  - Mathieu Robart, Arm

  - Marius Bjorge, Arm

  - Tom Olson, Arm

  - Sebastian Tafuri, EA

  - Henrik Rydgard, Embark

  - Juan Cañada, Epic Games

  - Patrick Kelly, Epic Games

  - Yuriy O’Donnell, Epic Games

  - Michael Doggett, Facebook/Oculus

  - Don Scorgie, Imagination

  - Dae Kim, Imagination

  - Joshua Barczak, Intel

  - Slawek Grajewski, Intel

  - Jeff Bolz, NVIDIA

  - Pascal Gautron, NVIDIA

  - Daniel Koch, NVIDIA

  - Christoph Kubisch, NVIDIA

  - Ashwin Lele, NVIDIA

  - Robert Stepinski, NVIDIA

  - Martin Stich, NVIDIA

  - Nuno Subtil, NVIDIA

  - Eric Werness, NVIDIA

  - Jon Leech, Khronos

  - Jeroen van Schijndel, OTOY

  - Juul Joosten, OTOY

  - Alex Bourd, Qualcomm

  - Roman Larionov, Qualcomm

  - David McAllister, Qualcomm

  - Andrew Garrard, Samsung

  - Lewis Gordon, Samsung

  - Ralph Potter, Samsung

  - Jasper Bekkers, Traverse Research

  - Jesse Barker, Unity

  - Baldur Karlsson, Valve

#### Description

Rasterization has been the dominant method to produce interactive graphics, but increasing performance of graphics hardware has made ray tracing a viable option for interactive rendering. Being able to integrate ray tracing with traditional rasterization makes it easier for applications to incrementally add ray traced effects to existing applications or to do hybrid approaches with rasterization for primary visibility and ray tracing for secondary queries.

To enable ray tracing, this extension adds a few different categories of new functionality:

- Acceleration structure objects and build commands

- A new pipeline type with new shader domains

- An indirection table to link shader groups with acceleration structure items

Additionally, ray queries are available to other shader types outside of the dedicated ray tracing pipeline. Unlike `OpTraceRayKHR`, ray queries are not able to launch additional shaders, instead returning traversal results to the calling shader.

This extension adds support for the following SPIR-V extension in Vulkan:

- `SPV_KHR_ray_tracing`

- `SPV_KHR_ray_query`

#### New Object Types

- VkAccelerationStructureKHR

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_RAY_TRACING_PIPELINE_CREATE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_BUILD_GEOMETRY_INFO_KHR`

  - `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_CREATE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_BIND_ACCELERATION_STRUCTURE_MEMORY_INFO_KHR`

  - `VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET_ACCELERATION_STRUCTURE_KHR`

  - `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_INFO_KHR`

  - `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_CREATE_GEOMETRY_TYPE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_GEOMETRY_TRIANGLES_DATA_KHR`

  - `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_GEOMETRY_AABBS_DATA_KHR`

  - `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_GEOMETRY_INSTANCES_DATA_KHR`

  - `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_GEOMETRY_KHR`

  - `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_DEVICE_ADDRESS_INFO_KHR`

  - `VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_VERSION_KHR`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_RAY_TRACING_PROPERTIES_KHR`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_RAY_TRACING_FEATURES_KHR`

  - `VK_STRUCTURE_TYPE_RAY_TRACING_PIPELINE_INTERFACE_CREATE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_RAY_TRACING_SHADER_GROUP_CREATE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_COPY_ACCELERATION_STRUCTURE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_COPY_ACCELERATION_STRUCTURE_TO_MEMORY_INFO_KHR`

  - `VK_STRUCTURE_TYPE_COPY_MEMORY_TO_ACCELERATION_STRUCTURE_INFO_KHR`

- Extending VkShaderStageFlagBits:

  - `VK_SHADER_STAGE_RAYGEN_BIT_KHR`

  - `VK_SHADER_STAGE_ANY_HIT_BIT_KHR`

  - `VK_SHADER_STAGE_CLOSEST_HIT_BIT_KHR`

  - `VK_SHADER_STAGE_MISS_BIT_KHR`

  - `VK_SHADER_STAGE_INTERSECTION_BIT_KHR`

  - `VK_SHADER_STAGE_CALLABLE_BIT_KHR`

- Extending VkPipelineStageFlagBits:

  - `VK_PIPELINE_STAGE_RAY_TRACING_SHADER_BIT_KHR`

  - `VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_KHR`

- Extending VkBufferUsageFlagBits:

  - `VK_BUFFER_USAGE_RAY_TRACING_BIT_KHR`

- Extending VkPipelineBindPoint:

  - `VK_PIPELINE_BIND_POINT_RAY_TRACING_KHR`

- Extending VkDescriptorType:

  - `VK_DESCRIPTOR_TYPE_ACCELERATION_STRUCTURE_KHR`

- Extending VkAccessFlagBits:

  - `VK_ACCESS_ACCELERATION_STRUCTURE_READ_BIT_KHR`

  - `VK_ACCESS_ACCELERATION_STRUCTURE_WRITE_BIT_KHR`

- Extending VkQueryType:

  - `VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_KHR`

  - `VK_QUERY_TYPE_ACCELERATION_STRUCTURE_SERIALIZATION_SIZE_KHR`

- Extending VkObjectType:

  - `VK_OBJECT_TYPE_ACCELERATION_STRUCTURE_KHR`

- Extending VkDebugReportObjectTypeEXT:

  - `VK_DEBUG_REPORT_OBJECT_TYPE_ACCELERATION_STRUCTURE_KHR_EXT`

- Extending VkIndexType:

  - `VK_INDEX_TYPE_NONE_KHR`

- Extending VkResult:

  - `VK_ERROR_INCOMPATIBLE_VERSION_KHR`

- Extending VkPipelineCreateFlagBits:

  - `VK_PIPELINE_CREATE_RAY_TRACING_SKIP_TRIANGLES_BIT_KHR`

  - `VK_PIPELINE_CREATE_RAY_TRACING_SKIP_AABBS_BIT_KHR`

#### New Enums

- VkAccelerationStructureMemoryRequirementsTypeKHR

- VkAccelerationStructureBuildTypeKHR

- VkAccelerationStructureTypeKHR

- VkBuildAccelerationStructureFlagBitsKHR

- VkCopyAccelerationStructureModeKHR

- VkGeometryFlagBitsKHR

- VkGeometryInstanceFlagBitsKHR

- VkGeometryTypeKHR

- VkRayTracingShaderGroupTypeKHR

#### New Structures

- VkAabbPositionsKHR

- VkAccelerationStructureBuildGeometryInfoKHR

- VkAccelerationStructureBuildOffsetInfoKHR

- VkAccelerationStructureCreateGeometryTypeInfoKHR

- VkAccelerationStructureCreateInfoKHR

- VkAccelerationStructureDeviceAddressInfoKHR

- VkAccelerationStructureGeometryAabbsDataKHR

- VkAccelerationStructureGeometryDataKHR

- VkAccelerationStructureGeometryInstancesDataKHR

- VkAccelerationStructureGeometryKHR

- VkAccelerationStructureGeometryTrianglesDataKHR

- VkAccelerationStructureInstanceKHR

- VkAccelerationStructureMemoryRequirementsInfoKHR

- VkAccelerationStructureVersionKHR

- VkBindAccelerationStructureMemoryInfoKHR

- VkTraceRaysIndirectCommandKHR

- VkCopyAccelerationStructureInfoKHR

- VkCopyAccelerationStructureToMemoryInfoKHR

- VkCopyMemoryToAccelerationStructureInfoKHR

- VkDeviceOrHostAddressKHR

- VkDeviceOrHostAddressConstKHR

- VkPhysicalDeviceRayTracingFeaturesKHR

- VkPhysicalDeviceRayTracingPropertiesKHR

- VkRayTracingPipelineCreateInfoKHR

- VkRayTracingShaderGroupCreateInfoKHR

- VkStridedBufferRegionKHR

- VkTransformMatrixKHR

- VkWriteDescriptorSetAccelerationStructureKHR

#### New Functions

- vkBindAccelerationStructureMemoryKHR

- vkBuildAccelerationStructureKHR

- vkCmdBuildAccelerationStructureIndirectKHR

- vkCmdBuildAccelerationStructureKHR

- vkCmdCopyAccelerationStructureKHR

- vkCmdCopyAccelerationStructureToMemoryKHR

- vkCmdCopyMemoryToAccelerationStructureKHR

- vkCmdTraceRaysIndirectKHR

- vkCmdTraceRaysKHR

- vkCmdWriteAccelerationStructuresPropertiesKHR

- vkCreateAccelerationStructureKHR

- vkCreateRayTracingPipelinesKHR

- vkCopyAccelerationStructureKHR

- vkCopyAccelerationStructureToMemoryKHR

- vkCopyMemoryToAccelerationStructureKHR

- vkDestroyAccelerationStructureKHR

- vkGetAccelerationStructureDeviceAddressKHR

- vkGetAccelerationStructureMemoryRequirementsKHR

- vkGetDeviceAccelerationStructureCompatibilityKHR

- vkGetRayTracingCaptureReplayShaderGroupHandlesKHR

- vkGetRayTracingShaderGroupHandlesKHR

- vkWriteAccelerationStructuresPropertiesKHR

#### New or Modified Built-In Variables

- `LaunchIDKHR`

- `LaunchSizeKHR`

- `WorldRayOriginKHR`

- `WorldRayDirectionKHR`

- `ObjectRayOriginKHR`

- `ObjectRayDirectionKHR`

- `RayTminKHR`

- `RayTmaxKHR`

- `InstanceCustomIndexKHR`

- `InstanceId`

- `ObjectToWorldKHR`

- `WorldToObjectKHR`

- `HitKindKHR`

- `IncomingRayFlagsKHR`

- (modified)`PrimitiveId`

#### New SPIR-V Capabilities

- RayTracingProvisionalKHR

- RayQueryProvisionalKHR

- RayTraversalPrimitiveCullingProvisionalKHR

#### Issues

(1) How does this extension differ from VK_NV_ray_tracing?

DISCUSSION:

The following is a summary of the main functional differences between VK_KHR_ray_tracing and VK_NV_ray_tracing:

- added support for indirect ray tracing (vkCmdTraceRaysIndirectKHR)

- uses SPV_KHR_ray_tracing instead of SPV_NV_ray_tracing

  - refer to KHR SPIR-V enums instead of NV SPIR-V enums (which are functionally equivalent and aliased to the same values).

  - added `RayGeometryIndexKHR` built-in

- added acceleration structure serialization / deserialization (`VK_COPY_ACCELERATION_STRUCTURE_MODE_SERIALIZE_KHR`, `VK_COPY_ACCELERATION_STRUCTURE_MODE_DESERIALIZE_KHR`, vkCmdCopyAccelerationStructureToMemoryKHR, vkCmdCopyMemoryToAccelerationStructureKHR)

- removed vkCompileDeferredNV compilation functionality and replaced with deferred host operations interactions for ray tracing

- document inactive primitives and instances

- added VkPhysicalDeviceRayTracingFeaturesKHR structure

- extended VkPhysicalDeviceRayTracingPropertiesKHR

  - `maxRecursionDepth` has a minimum of 1 instead of 31

  - require `shaderGroupHandleSize` to be 32 bytes

- added indirect and batched acceleration structure builds (vkCmdBuildAccelerationStructureIndirectKHR)

- added host acceleration structure commands

- reworked geometry structures so they could be better shared between device, host, and indirect builds

- added `geometryArrayOfPointers` and made instances more like triangles and AABBs.

- changed SBT parameters to a structure and added size (VkStridedBufferRegionKHR)

- explicitly made VkAccelerationStructureKHR use device addresses

- added ability to capture and replay shader group handles and acceleration structures

- added acceleration structure compatibility check function (vkGetDeviceAccelerationStructureCompatibilityKHR)

- add parameter for requesting memory requirements for host and/or device build

- added pipeline library support for ray tracing

- added watertightness guarantees

- added format feature for accesleration structure build vertex formats (`VK_FORMAT_FEATURE_ACCELERATION_STRUCTURE_VERTEX_BUFFER_BIT_KHR`)

- added no-null-shader pipeline flags (`VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_*_SHADERS_BIT_KHR`)

- added memory model interactions with ray tracing and define how subgroups work and can be repacked

- added ray query and SPV_KHR_ray_query support

(2) Can you give a more detailed comparision of differences and similarities between VK_NV_ray_tracing and VK_KHR_ray_tracing?

DISCUSSION:

The following is a more detailed comparision of which commands, structures, and enums are aliased, changed, or removed.

- Aliased functionality — enums, structures, and commands that are considered equivalent:

  - VkAccelerationStructureNV ←→ VkAccelerationStructureKHR

  - VkRayTracingShaderGroupTypeNV ←→ VkRayTracingShaderGroupTypeKHR

  - VkGeometryTypeNV ←→ VkGeometryTypeKHR

  - VkAccelerationStructureTypeNV ←→ VkAccelerationStructureTypeKHR

  - VkCopyAccelerationStructureModeNV ←→ VkCopyAccelerationStructureModeKHR

  - VkAccelerationStructureMemoryRequirementsTypeNV ←→ VkAccelerationStructureMemoryRequirementsTypeKHR

  - VkGeometryFlagsNV ←→ VkGeometryFlagsKHR

  - VkGeometryFlagBitsNV ←→ VkGeometryFlagBitsKHR

  - VkGeometryInstanceFlagsNV ←→ VkGeometryInstanceFlagsKHR

  - VkGeometryInstanceFlagBitsNV ←→ VkGeometryInstanceFlagBitsKHR

  - VkBuildAccelerationStructureFlagsNV ←→ VkBuildAccelerationStructureFlagsKHR

  - VkBuildAccelerationStructureFlagBitsNV ←→ VkBuildAccelerationStructureFlagBitsKHR

  - VkBindAccelerationStructureMemoryInfoNV ←→ VkBindAccelerationStructureMemoryInfoKHR

  - VkWriteDescriptorSetAccelerationStructureNV ←→ VkWriteDescriptorSetAccelerationStructureKHR

  - VkTransformMatrixNV ←→ VkTransformMatrixKHR (added to NV_ray_tracing for descriptive purposes)

  - VkAabbPositionsNV ←→ VkAabbPositionsKHR (added to NV_ray_tracing for descriptive purposes)

  - VkAccelerationStructureInstanceNV ←→ VkAccelerationStructureInstanceKHR (added to NV_ray_tracing for descriptive purposes)

  - vkDestroyAccelerationStructureNV ←→ vkDestroyAccelerationStructureKHR

  - vkBindAccelerationStructureMemoryNV ←→ vkBindAccelerationStructureMemoryKHR

  - vkGetRayTracingShaderGroupHandlesNV ←→ vkGetRayTracingShaderGroupHandlesKHR

  - vkCmdWriteAccelerationStructuresPropertiesNV ←→ vkCmdWriteAccelerationStructuresPropertiesKHR

- Changed enums, structures, and commands:

  - renamed `VK_GEOMETRY_INSTANCE_TRIANGLE_CULL_DISABLE_BIT_NV` → `VK_GEOMETRY_INSTANCE_TRIANGLE_FACING_CULL_DISABLE_BIT_KHR` in VkGeometryInstanceFlagBitsKHR

  - VkRayTracingShaderGroupCreateInfoNV → VkRayTracingShaderGroupCreateInfoKHR (added `pShaderGroupCaptureReplayHandle`)

  - VkRayTracingPipelineCreateInfoNV → VkRayTracingPipelineCreateInfoKHR (changed type of `pGroups`, added `libraries` and `pLibraryInterface`)

  - VkGeometryTrianglesNV → VkAccelerationStructureGeometryTrianglesDataKHR (device or host address instead of buffer+offset)

  - VkGeometryAABBNV → VkAccelerationStructureGeometryAabbsDataKHR (device or host address instead of buffer+offset)

  - VkGeometryDataNV → VkAccelerationStructureGeometryDataKHR (union of triangle/aabbs/instances)

  - VkGeometryNV → VkAccelerationStructureGeometryKHR (changed type of geometry)

  - VkAccelerationStructureInfoNV → VkAccelerationStructureCreateGeometryTypeInfoKHR (reshuffle geometry layout/info, instances moved to VkAccelerationStructureGeometryDataKHR)

  - VkAccelerationStructureCreateInfoNV → VkAccelerationStructureCreateInfoKHR (reshuffle geometry layout/info)

  - VkPhysicalDeviceRayTracingPropertiesNV → VkPhysicalDeviceRayTracingPropertiesKHR (renamed `maxTriangleCount` to `maxPrimitiveCount`, added `shaderGroupHandleCaptureReplaySize`)

  - VkAccelerationStructureMemoryRequirementsInfoNV → VkAccelerationStructureMemoryRequirementsInfoKHR (added `buildType`)

  - vkCreateAccelerationStructureNV → vkCreateAccelerationStructureKHR (device address, different geometry layout/info)

  - vkGetAccelerationStructureMemoryRequirementsNV → vkGetAccelerationStructureMemoryRequirementsKHR (different structs)

  - vkCmdBuildAccelerationStructureNV → vkCmdBuildAccelerationStructureKHR (params moved to structs, layout differences)

  - vkCmdCopyAccelerationStructureNV → vkCmdCopyAccelerationStructureKHR (params to struct, extendable)

  - vkCmdTraceRaysNV → vkCmdTraceRaysKHR (params to struct)

  - vkCreateRayTracingPipelinesNV → vkCreateRayTracingPipelinesKHR (different struct, changed functionality)

  - vkGetAccelerationStructureHandleNV → vkGetAccelerationStructureDeviceAddressKHR (device address instead of handle)

- Added enums, structures and commands:

  - `VK_GEOMETRY_TYPE_INSTANCES_KHR` to VkGeometryTypeKHR enum

  - `VK_COPY_ACCELERATION_STRUCTURE_MODE_SERIALIZE_KHR`, `VK_COPY_ACCELERATION_STRUCTURE_MODE_DESERIALIZE_KHR` to VkCopyAccelerationStructureModeKHR enum

  - `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_ANY_HIT_SHADERS_BIT_KHR` `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_CLOSEST_HIT_SHADERS_BIT_KHR`, `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_MISS_SHADERS_BIT_KHR`, `VK_PIPELINE_CREATE_RAY_TRACING_NO_NULL_INTERSECTION_SHADERS_BIT_KHR`, `VK_PIPELINE_CREATE_RAY_TRACING_SKIP_TRIANGLES_BIT_KHR`, `VK_PIPELINE_CREATE_RAY_TRACING_SKIP_AABBS_BIT_KHR` to VkPipelineCreateFlagBits

  - VkPhysicalDeviceRayTracingFeaturesKHR structure

  - VkAccelerationStructureBuildTypeKHR enum

  - VkDeviceOrHostAddressKHR and VkDeviceOrHostAddressConstKHR unions

  - VkPipelineLibraryCreateInfoKHR struct

  - VkRayTracingPipelineInterfaceCreateInfoKHR struct

  - VkAccelerationStructureBuildOffsetInfoKHR struct

  - VkAccelerationStructureGeometryInstancesDataKHR struct

  - VkAccelerationStructureDeviceAddressInfoKHR struct

  - VkAccelerationStructureVersionKHR struct

  - VkStridedBufferRegionKHR struct

  - VkTraceRaysIndirectCommandKHR struct

  - VkCopyAccelerationStructureToMemoryInfoKHR struct

  - VkCopyMemoryToAccelerationStructureInfoKHR struct

  - VkCopyAccelerationStructureInfoKHR struct

  - vkBuildAccelerationStructureKHR command (host build)

  - vkCopyAccelerationStructureKHR command (host copy)

  - vkCopyAccelerationStructureToMemoryKHR (host serialize)

  - vkCopyMemoryToAccelerationStructureKHR (host deserialize)

  - vkWriteAccelerationStructuresPropertiesKHR (host properties)

  - vkCmdCopyAccelerationStructureToMemoryKHR (device serialize)

  - vkCmdCopyMemoryToAccelerationStructureKHR (device deserialize)

  - vkGetRayTracingCaptureReplayShaderGroupHandlesKHR (shader group capture/replay)

  - vkGetDeviceAccelerationStructureCompatibilityKHR (serialization)

- Functionality removed:

  - `VK_PIPELINE_CREATE_DEFER_COMPILE_BIT_NV`

  - vkCompileDeferredNV command

#### Sample Code

Example ray generation GLSL shader

    #version 450 core
    #extension GL_EXT_ray_tracing : require
    layout(set = 0, binding = 0, rgba8) uniform image2D image;
    layout(set = 0, binding = 1) uniform accelerationStructureEXT as;
    layout(location = 0) rayPayloadEXT float payload;

    void main()
    {
       vec4 col = vec4(0, 0, 0, 1);

       vec3 origin = vec3(float(gl_LaunchIDEXT.x)/float(gl_LaunchSizeEXT.x), float(gl_LaunchIDEXT.y)/float(gl_LaunchSizeEXT.y), 1.0);
       vec3 dir = vec3(0.0, 0.0, -1.0);

       traceRayEXT(as, 0, 0xff, 0, 1, 0, origin, 0.0, dir, 1000.0, 0);

       col.y = payload;

       imageStore(image, ivec2(gl_LaunchIDEXT.xy), col);
    }

#### Version History

- Revision 1, 2019-12-05 (Members of the Vulkan Ray Tracing TSG)

  - Internal revisions (forked from NV_ray_tracing)

- Revision 2, 2019-12-20 (Daniel Koch, Eric Werness)

  - Add const version of DeviceOrHostAddress (!3515)

  - Add VU to clarify that only handles in the current pipeline are valid (!3518)

  - Restore some missing VUs and add in-place update language (#1902, !3522)

  - rename VkAccelerationStructureInstanceKHR member from accelerationStructure to accelerationStructureReference to better match its type (!3523)

  - Allow VK_ERROR_INVALID_OPAQUE_CAPTURE_ADDRESS for pipeline creation if shader group handles cannot be re-used. (!3523)

  - update documentation for the VK_ERROR_INVALID_OPAQUE_CAPTURE_ADDRESS error code and add missing documentation for new return codes from VK_KHR_deferred_host_operations (!3523)

  - list new query types for VK_KHR_ray_tracing (!3523)

  - Fix VU statements for VkAccelerationStructureGeometryKHR referring to correct union members and update to use more current wording (!3523)

- Revision 3, 2020-01-10 (Daniel Koch, Jon Leech, Christoph Kubisch)

  - Fix 'instance of' and 'that/which contains/defines' markup issues (!3528)

  - factor out VK_KHR_pipeline_library as stand-alone extension (!3540)

  - Resolve Vulkan-hpp issues (!3543)

  - add missing require for VkGeometryInstanceFlagsKHR

  - de-alias VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_CREATE_INFO_NV since the KHR structure is no longer equivalent

  - add len to pDataSize attribute for vkWriteAccelerationStructuresPropertiesKHR

- Revision 4, 2020-01-23 (Daniel Koch, Eric Werness)

  - Improve vkWriteAccelerationStructuresPropertiesKHR, add return value and VUs (#1947)

  - Clarify language to allow multiple raygen shaders (#1959)

  - Various editorial feedback (!3556)

  - Add language to help deal with looped self-intersecting fans (#1901)

  - Change vkCmdTraceRays{Indirect}KHR args to pointers (!3559)

  - Add scratch address validation language (#1941, !3551)

  - Fix definition and add hierarchy information for shader call scope (#1977, !3571)

- Revision 5, 2020-02-04 (Eric Werness, Jeff Bolz, Daniel Koch)

  - remove vestigial accelerationStructureUUID (!3582)

  - update definition of repack instructions and improve memory model interactions (#1910, #1913, !3584)

  - Fix wrong sType for VkPhysicalDeviceRayTracingFeaturesKHR (#1988)

  - Use provisional SPIR-V capabilities (#1987)

  - require rayTracingPrimitiveCulling if rayQuery is supported (#1927)

  - Miss shaders do not have object parameters (!3592)

  - Fix missing required types in XML (!3592)

  - clarify matching conditions for update (!3592)

  - add goal that host and device builds be similar (!3592)

  - clarify that `maxPrimitiveCount` limit should apply to triangles and AABBs (!3592)

  - Require alignment for instance arrayOfPointers (!3592)

  - Zero is a valid value for instance flags (!3592)

  - Add some alignment VUs that got lost in refactoring (!3592)

  - Recommend TMin epsilon rather than culling (!3592)

  - Get angle from dot product not cross product (!3592)

  - Clarify that AH can access the payload and attributes (!3592)

  - Match DXR behavior for inactive primitive definition (!3592)

  - Use a more generic term than degenerate for inactive to avoid confusion (!3592)

- Revision 6, 2020-02-20 (Daniel Koch)

  - fix some dangling NV references (#1996)

  - rename VkCmdTraceRaysIndirectCommandKHR to VkTraceRaysIndirectCommandKHR (!3607)

  - update contributor list (!3611)

  - use uint64_t instead of VkAccelerationStructureReferenceKHR in VkAccelerationStructureInstanceKHR (#2004)

- Revision 7, 2020-02-28 (Tobias Hector)

  - remove HitTKHR SPIR-V builtin (spirv/spirv-extensions#7)

- Revision 8, 2020-03-06 (Tobias Hector, Dae Kim, Daniel Koch, Jeff Bolz, Eric Werness)

  - explicitly state that Tmax is updated when new closest intersection is accepted (#2020,!3536)

  - Made references to min and max t values consistent (!3644)

  - finish enumerating differences relative to NV_ray_tracing in issues (1) and (2) (#1974,!3642)

  - fix formatting in some math equations (!3642)

  - Restrict the Hit Kind operand of `OpReportIntersectionKHR` to 7-bits (spirv/spirv-extensions#8,!3646)

  - Say raytracing 'should' be watertight (#2008,!3631)

  - Clarify memory requirements for ray tracing buffers (#2005,!3649)

  - Add callable size limits (#1997,!3652)

### List of Deprecated Extensions

- `VK_KHR_16bit_storage`

- `VK_KHR_8bit_storage`

- `VK_KHR_bind_memory2`

- `VK_KHR_buffer_device_address`

- `VK_KHR_create_renderpass2`

- `VK_KHR_dedicated_allocation`

- `VK_KHR_depth_stencil_resolve`

- `VK_KHR_descriptor_update_template`

- `VK_KHR_device_group`

- `VK_KHR_device_group_creation`

- `VK_KHR_draw_indirect_count`

- `VK_KHR_driver_properties`

- `VK_KHR_external_fence`

- `VK_KHR_external_fence_capabilities`

- `VK_KHR_external_memory`

- `VK_KHR_external_memory_capabilities`

- `VK_KHR_external_semaphore`

- `VK_KHR_external_semaphore_capabilities`

- `VK_KHR_get_memory_requirements2`

- `VK_KHR_get_physical_device_properties2`

- `VK_KHR_image_format_list`

- `VK_KHR_imageless_framebuffer`

- `VK_KHR_maintenance1`

- `VK_KHR_maintenance2`

- `VK_KHR_maintenance3`

- `VK_KHR_multiview`

- `VK_KHR_relaxed_block_layout`

- `VK_KHR_sampler_mirror_clamp_to_edge`

- `VK_KHR_sampler_ycbcr_conversion`

- `VK_KHR_separate_depth_stencil_layouts`

- `VK_KHR_shader_atomic_int64`

- `VK_KHR_shader_draw_parameters`

- `VK_KHR_shader_float16_int8`

- `VK_KHR_shader_float_controls`

- `VK_KHR_shader_subgroup_extended_types`

- `VK_KHR_spirv_1_4`

- `VK_KHR_storage_buffer_storage_class`

- `VK_KHR_timeline_semaphore`

- `VK_KHR_uniform_buffer_standard_layout`

- `VK_KHR_variable_pointers`

- `VK_KHR_vulkan_memory_model`

- `VK_EXT_buffer_device_address`

- `VK_EXT_debug_marker`

- `VK_EXT_debug_report`

- `VK_EXT_descriptor_indexing`

- `VK_EXT_host_query_reset`

- `VK_EXT_sampler_filter_minmax`

- `VK_EXT_scalar_block_layout`

- `VK_EXT_separate_stencil_usage`

- `VK_EXT_shader_subgroup_ballot`

- `VK_EXT_shader_subgroup_vote`

- `VK_EXT_shader_viewport_index_layer`

- `VK_EXT_validation_flags`

- `VK_AMD_draw_indirect_count`

- `VK_AMD_gpu_shader_half_float`

- `VK_AMD_gpu_shader_int16`

- `VK_AMD_negative_viewport_height`

- `VK_NV_dedicated_allocation`

- `VK_NV_external_memory`

- `VK_NV_external_memory_capabilities`

- `VK_NV_external_memory_win32`

- `VK_NV_glsl_shader`

- `VK_NV_win32_keyed_mutex`

#### VK_KHR_16bit_storage

Name String

  `VK_KHR_16bit_storage`

Extension Type

  Device extension

Registered Extension Number

  84

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

  - Requires `VK_KHR_storage_buffer_storage_class`

Deprecation state

  - Promoted to Vulkan 1.1

Contact

  - Jan-Harald Fredriksen janharaldfredriksen-arm

Last Modified Date

  2017-09-05

IP Status

  No known IP claims.

Interactions and External Dependencies

  - This extension requires `SPV_KHR_16bit_storage`

  - Promoted to Vulkan 1.1 Core

Contributors

  - Alexander Galazin, ARM

  - Jan-Harald Fredriksen, ARM

  - Joerg Wagner, ARM

  - Neil Henning, Codeplay

  - Jeff Bolz, Nvidia

  - Daniel Koch, Nvidia

  - David Neto, Google

  - John Kessenich, Google

The `VK_KHR_16bit_storage` extension allows use of 16-bit types in shader input and output interfaces, and push constant blocks. This extension introduces several new optional features which map to SPIR-V capabilities and allow access to 16-bit data in `Block`-decorated objects in the `Uniform` and the `StorageBuffer` storage classes, and objects in the `PushConstant` storage class. This extension allows 16-bit variables to be declared and used as user-defined shader inputs and outputs but does not change location assignment and component assignment rules.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_16BIT_STORAGE_FEATURES_KHR`

#### New Structures

- VkPhysicalDevice16BitStorageFeaturesKHR

#### New SPIR-V Capabilities

- `StorageBuffer16BitAccess`

- `UniformAndStorageBuffer16BitAccess`

- `StoragePushConstant16`

- `StorageInputOutput16`

#### Promotion to Vulkan 1.1

All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

#### Version History

- Revision 1, 2017-03-23 (Alexander Galazin)

  - Initial draft

#### VK_KHR_8bit_storage

Name String

  `VK_KHR_8bit_storage`

Extension Type

  Device extension

Registered Extension Number

  178

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

  - Requires `VK_KHR_storage_buffer_storage_class`

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Alexander Galazin alegal-arm

Last Modified Date

  2018-02-05

Interactions and External Dependencies

  - Promoted to Vulkan 1.2 Core

IP Status

  No known IP claims.

Interactions and External Dependencies

  - This extension requires `SPV_KHR_8bit_storage`

Contributors

  - Alexander Galazin, Arm

The `VK_KHR_8bit_storage` extension allows use of 8-bit types in uniform and storage buffers, and push constant blocks. This extension introduces several new optional features which map to SPIR-V capabilities and allow access to 8-bit data in `Block`-decorated objects in the `Uniform` and the `StorageBuffer` storage classes, and objects in the `PushConstant` storage class.

The `StorageBuffer8BitAccess` capability must be supported by all implementations of this extension. The other capabilities are optional.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_8BIT_STORAGE_FEATURES_KHR`

#### New Structures

- VkPhysicalDevice8BitStorageFeaturesKHR

#### New SPIR-V Capabilities

- `StorageBuffer8BitAccess`

- `UniformAndStorageBuffer8BitAccess`

- `StoragePushConstant8`

#### Promotion to Vulkan 1.2

Functionality in this extension is included in core Vulkan 1.2, with the KHR suffix omitted. However, if Vulkan 1.2 is supported and this extension is not, the `StorageBuffer8BitAccess` capability is optional. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

#### Version History

- Revision 1, 2018-02-05 (Alexander Galazin)

  - Initial draft

#### VK_KHR_bind_memory2

Name String

  `VK_KHR_bind_memory2`

Extension Type

  Device extension

Registered Extension Number

  158

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Promoted to Vulkan 1.1

Contact

  - Tobias Hector tobski

Last Modified Date

  2017-09-05

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Promoted to Vulkan 1.1 Core

Contributors

  - Jeff Bolz, NVIDIA

  - Tobias Hector, Imagination Technologies

This extension provides versions of vkBindBufferMemory and vkBindImageMemory that allow multiple bindings to be performed at once, and are extensible.

This extension also introduces `VK_IMAGE_CREATE_ALIAS_BIT_KHR`, which allows “identical” images that alias the same memory to interpret the contents consistently, even across image layout changes.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_BIND_BUFFER_MEMORY_INFO_KHR`

  - `VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_INFO_KHR`

- Extending VkImageCreateFlagBits:

  - `VK_IMAGE_CREATE_ALIAS_BIT_KHR`

#### New Enums

None.

#### New Structures

- VkBindBufferMemoryInfoKHR

- VkBindImageMemoryInfoKHR

#### New Functions

- vkBindBufferMemory2KHR

- vkBindImageMemory2KHR

#### New Built-In Variables

None.

#### New SPIR-V Capabilities

None.

#### Promotion to Vulkan 1.1

All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

None.

#### Version History

- Revision 1, 2017-05-19 (Tobias Hector)

  - Pulled bind memory functions into their own extension

#### VK_KHR_buffer_device_address

Name String

  `VK_KHR_buffer_device_address`

Extension Type

  Device extension

Registered Extension Number

  258

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Jeff Bolz jeffbolznv

Last Modified Date

  2019-06-24

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Promoted to Vulkan 1.2 Core

Contributors

  - Jeff Bolz, NVIDIA

  - Neil Henning, AMD

  - Tobias Hector, AMD

  - Jason Ekstrand, Intel

  - Baldur Karlsson, Valve

  - Jan-Harald Fredriksen, Arm

This extension allows the application to query a 64-bit buffer device address value for a buffer, which can be used to access the buffer memory via the `PhysicalStorageBuffer` storage class in the `GL_EXT_buffer_reference` GLSL extension and `SPV_KHR_physical_storage_buffer` SPIR-V extension.

This extension also allows opaque addresses for buffers and memory objects to be queried and later supplied by a trace capture and replay tool, so that addresses used at replay time match the addresses used when the trace was captured. To enable tools to insert these queries, new memory allocation flags must be specified for memory objects that will be bound to buffers accessed via the `PhysicalStorageBuffer` storage class.

#### New Object Types

None

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_BUFFER_DEVICE_ADDRESS_FEATURES_KHR`

  - `VK_STRUCTURE_TYPE_BUFFER_DEVICE_ADDRESS_INFO_KHR`

  - `VK_STRUCTURE_TYPE_BUFFER_OPAQUE_CAPTURE_ADDRESS_CREATE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_MEMORY_OPAQUE_CAPTURE_ADDRESS_ALLOCATE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_DEVICE_MEMORY_OPAQUE_CAPTURE_ADDRESS_INFO_KHR`

- Extending VkBufferUsageFlagBits:

  - `VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT_KHR`

- Extending VkBufferCreateFlagBits:

  - `VK_BUFFER_CREATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT_KHR`

- Extending VkMemoryAllocateFlagBits:

  - `VK_MEMORY_ALLOCATE_DEVICE_ADDRESS_BIT_KHR`

  - `VK_MEMORY_ALLOCATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT_KHR`

- Extending VkResult:

  - `VK_ERROR_INVALID_OPAQUE_CAPTURE_ADDRESS_KHR`

#### New Enums

None

#### New Structures

- VkPhysicalDeviceBufferDeviceAddressFeaturesKHR

- VkBufferDeviceAddressInfoKHR

- VkBufferOpaqueCaptureAddressCreateInfoKHR

- VkMemoryOpaqueCaptureAddressAllocateInfoKHR

- VkDeviceMemoryOpaqueCaptureAddressInfoKHR

#### New Functions

- vkGetBufferDeviceAddressKHR

- vkGetBufferOpaqueCaptureAddressKHR

- vkGetDeviceMemoryOpaqueCaptureAddressKHR

#### New Built-In Variables

None

#### New SPIR-V Capabilities

- `PhysicalStorageBufferAddresses`

#### Promotion to Vulkan 1.2

All functionality in this extension is included in core Vulkan 1.2, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

None

#### Version History

- Revision 1, 2019-06-24 (Jan-Harald Fredriksen)

  - Internal revisions based on VK_EXT_buffer_device_address

#### VK_KHR_create_renderpass2

Name String

  `VK_KHR_create_renderpass2`

Extension Type

  Device extension

Registered Extension Number

  110

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_multiview`

  - Requires `VK_KHR_maintenance2`

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Tobias Hector tobias

Last Modified Date

  2018-02-07

Interactions and External Dependencies

  - Promoted to Vulkan 1.2 Core

Contributors

  - Tobias Hector

  - Jeff Bolz

This extension provides a new entry point to create render passes in a way that can be easily extended by other extensions through the substructures of render pass creation. The Vulkan 1.0 render pass creation sub-structures do not include `sType`/`pNext` members. Additionally, the renderpass begin/next/end commands have been augmented with new extensible structures for passing additional subpass information.

The VkRenderPassMultiviewCreateInfo and VkInputAttachmentAspectReference structures that extended the original VkRenderPassCreateInfo are not accepted into the new creation functions, and instead their parameters are folded into this extension as follows:

- Elements of VkRenderPassMultiviewCreateInfo::`pViewMasks` are now specified in VkSubpassDescription2KHR::`viewMask`.

- Elements of VkRenderPassMultiviewCreateInfo::`pViewOffsets` are now specified in VkSubpassDependency2KHR::`viewOffset`.

- VkRenderPassMultiviewCreateInfo::`correlationMaskCount` and VkRenderPassMultiviewCreateInfo::`pCorrelationMasks` are directly specified in VkRenderPassCreateInfo2KHR.

- VkInputAttachmentAspectReference::`aspectMask` is now specified in the relevant input attachment description in VkAttachmentDescription2KHR::`aspectMask`

The details of these mappings are explained fully in the new structures.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_ATTACHMENT_DESCRIPTION_2_KHR`

  - `VK_STRUCTURE_TYPE_ATTACHMENT_REFERENCE_2_KHR`

  - `VK_STRUCTURE_TYPE_SUBPASS_DESCRIPTION_2_KHR`

  - `VK_STRUCTURE_TYPE_SUBPASS_DEPENDENCY_2_KHR`

  - `VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO_2_KHR`

  - `VK_STRUCTURE_TYPE_SUBPASS_BEGIN_INFO_KHR`

  - `VK_STRUCTURE_TYPE_SUBPASS_END_INFO_KHR`

#### New Structures

- VkAttachmentDescription2KHR

- VkAttachmentReference2KHR

- VkSubpassDescription2KHR

- VkSubpassDependency2KHR

- VkRenderPassCreateInfo2KHR

- VkSubpassBeginInfoKHR

- VkSubpassEndInfoKHR

#### New Functions

- vkCreateRenderPass2KHR

- vkCmdBeginRenderPass2KHR

- vkCmdNextSubpass2KHR

- vkCmdEndRenderPass2KHR

#### Promotion to Vulkan 1.2

All functionality in this extension is included in core Vulkan 1.2, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Version History

- Revision 1, 2018-02-07 (Tobias Hector)

  - Internal revisions

#### VK_KHR_dedicated_allocation

Name String

  `VK_KHR_dedicated_allocation`

Extension Type

  Device extension

Registered Extension Number

  128

Revision

  3

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_memory_requirements2`

Deprecation state

  - Promoted to Vulkan 1.1

Contact

  - James Jones cubanismo

Last Modified Date

  2017-09-05

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Promoted to Vulkan 1.1 Core

Contributors

  - Jeff Bolz, NVIDIA

  - Jason Ekstrand, Intel

This extension enables resources to be bound to a dedicated allocation, rather than suballocated. For any particular resource, applications can query whether a dedicated allocation is recommended, in which case using a dedicated allocation may improve the performance of access to that resource. Normal device memory allocations must support multiple resources per allocation, memory aliasing and sparse binding, which could interfere with some optimizations. Applications should query the implementation for when a dedicated allocation may be beneficial by adding a `VkMemoryDedicatedRequirementsKHR` structure to the `pNext` chain of the `VkMemoryRequirements2` structure passed as the `pMemoryRequirements` parameter of a call to `vkGetBufferMemoryRequirements2` or `vkGetImageMemoryRequirements2`. Certain external handle types and external images or buffers may also depend on dedicated allocations on implementations that associate image or buffer metadata with OS-level memory objects.

This extension adds a two small structures to memory requirements querying and memory allocation: a new structure that flags whether an image/buffer should have a dedicated allocation, and a structure indicating the image or buffer that an allocation will be bound to.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_MEMORY_DEDICATED_REQUIREMENTS_KHR`

  - `VK_STRUCTURE_TYPE_MEMORY_DEDICATED_ALLOCATE_INFO_KHR`

#### New Enums

None.

#### New Structures

- VkMemoryDedicatedRequirementsKHR

- VkMemoryDedicatedAllocateInfoKHR

#### New Functions

None.

#### Promotion to Vulkan 1.1

All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

None.

#### Examples

        // Create an image with a dedicated allocation based on the
        // implementation's preference

        VkImageCreateInfo imageCreateInfo =
        {
            // Image creation parameters
        };

        VkImage image;
        VkResult result = vkCreateImage(
            device,
            &imageCreateInfo,
            NULL,                               // pAllocator
            &image);

        VkMemoryDedicatedRequirementsKHR dedicatedRequirements =
        {
            VK_STRUCTURE_TYPE_MEMORY_DEDICATED_REQUIREMENTS_KHR,
            NULL,                               // pNext
        };

        VkMemoryRequirements2 memoryRequirements =
        {
            VK_STRUCTURE_TYPE_MEMORY_REQUIREMENTS_2,
            &dedicatedRequirements,             // pNext
        };

        const VkImageMemoryRequirementsInfo2 imageRequirementsInfo =
        {
            VK_STRUCTURE_TYPE_IMAGE_MEMORY_REQUIREMENTS_INFO_2,
            NULL,                               // pNext
            image
        };

        vkGetImageMemoryRequirements2(
            device,
            &imageRequirementsInfo,
            &memoryRequirements);

        if (dedicatedRequirements.prefersDedicatedAllocation) {
            // Allocate memory with VkMemoryDedicatedAllocateInfoKHR::image
            // pointing to the image we are allocating the memory for

            VkMemoryDedicatedAllocateInfoKHR dedicatedInfo =
            {
                VK_STRUCTURE_TYPE_MEMORY_DEDICATED_ALLOCATE_INFO_KHR,   // sType
                NULL,                                                   // pNext
                image,                                                  // image
                VK_NULL_HANDLE,                                         // buffer
            };

            VkMemoryAllocateInfo memoryAllocateInfo =
            {
                VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO,                 // sType
                &dedicatedInfo,                                         // pNext
                memoryRequirements.size,                                // allocationSize
                FindMemoryTypeIndex(memoryRequirements.memoryTypeBits), // memoryTypeIndex
            };

            VkDeviceMemory memory;
            vkAllocateMemory(
                device,
                &memoryAllocateInfo,
                NULL,                       // pAllocator
                &memory);

            // Bind the image to the memory

            vkBindImageMemory(
                device,
                image,
                memory,
                0);
        } else {
            // Take the normal memory sub-allocation path
        }

#### Version History

- Revision 1, 2017-02-27 (James Jones)

  - Copy content from VK_NV_dedicated_allocation

  - Add some references to external object interactions to the overview.

- Revision 2, 2017-03-27 (Jason Ekstrand)

  - Rework the extension to be query-based

- Revision 3, 2017-07-31 (Jason Ekstrand)

  - Clarify that memory objects created with VkMemoryDedicatedAllocateInfoKHR can only have the specified resource bound and no others.

#### VK_KHR_depth_stencil_resolve

Name String

  `VK_KHR_depth_stencil_resolve`

Extension Type

  Device extension

Registered Extension Number

  200

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_create_renderpass2`

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Jan-Harald Fredriksen janharald

Last Modified Date

  2018-04-09

Interactions and External Dependencies

  - Promoted to Vulkan 1.2 Core

Contributors

  - Jan-Harald Fredriksen, Arm

  - Andrew Garrard, Samsung Electronics

  - Soowan Park, Samsung Electronics

  - Jeff Bolz, NVIDIA

  - Daniel Rakos, AMD

This extension adds support for automatically resolving multisampled depth/stencil attachments in a subpass in a similar manner as for color attachments.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_SUBPASS_DESCRIPTION_DEPTH_STENCIL_RESOLVE_KHR`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DEPTH_STENCIL_RESOLVE_PROPERTIES_KHR`

#### New Enums

- VkResolveModeFlagBitsKHR

#### New Structures

- VkPhysicalDeviceDepthStencilResolvePropertiesKHR

- VkSubpassDescriptionDepthStencilResolveKHR

#### New Functions

None.

#### Promotion to Vulkan 1.2

All functionality in this extension is included in core Vulkan 1.2, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Version History

- Revision 1, 2018-04-09 (Jan-Harald Fredriksen)

  - Initial revision

#### VK_KHR_descriptor_update_template

Name String

  `VK_KHR_descriptor_update_template`

Extension Type

  Device extension

Registered Extension Number

  86

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Promoted to Vulkan 1.1

Contact

  - Markus Tavenrath mtavenrath

Last Modified Date

  2017-09-05

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Interacts with `VK_KHR_push_descriptor`

  - Promoted to Vulkan 1.1 Core

Contributors

  - Jeff Bolz, NVIDIA

  - Michael Worcester, Imagination Technologies

Applications may wish to update a fixed set of descriptors in a large number of descriptors sets very frequently, i.e. during initializaton phase or if it is required to rebuild descriptor sets for each frame. For those cases it is also not unlikely that all information required to update a single descriptor set is stored in a single struct. This extension provides a way to update a fixed set of descriptors in a single VkDescriptorSet with a pointer to a user defined data structure describing the new descriptors.

#### New Object Types

- `VkDescriptorUpdateTemplateKHR`

#### New Enum Constants

Extending VkStructureType:

- `VK_STRUCTURE_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_CREATE_INFO_KHR`

#### New Enums

- VkDescriptorUpdateTemplateCreateFlagsKHR

- VkDescriptorUpdateTemplateTypeKHR

#### New Structures

- VkDescriptorUpdateTemplateEntryKHR

- VkDescriptorUpdateTemplateCreateInfoKHR

#### New Functions

- vkCreateDescriptorUpdateTemplateKHR

- vkDestroyDescriptorUpdateTemplateKHR

- vkUpdateDescriptorSetWithTemplateKHR

- vkCmdPushDescriptorSetWithTemplateKHR

#### Promotion to Vulkan 1.1

vkCmdPushDescriptorSetWithTemplateKHR is included as an interaction with `VK_KHR_push_descriptor`. If Vulkan 1.1 and `VK_KHR_push_descriptor` are supported, this is included by `VK_KHR_push_descriptor`.

The base functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Version History

- Revision 1, 2016-01-11 (Markus Tavenrath)

  - Initial draft

#### VK_KHR_device_group

Name String

  `VK_KHR_device_group`

Extension Type

  Device extension

Registered Extension Number

  61

Revision

  4

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_device_group_creation`

Deprecation state

  - Promoted to Vulkan 1.1

Contact

  - Jeff Bolz jeffbolznv

Last Modified Date

  2017-10-10

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Promoted to Vulkan 1.1 Core

Contributors

  - Jeff Bolz, NVIDIA

  - Tobias Hector, Imagination Technologies

This extension provides functionality to use a logical device that consists of multiple physical devices, as created with the `VK_KHR_device_group_creation` extension. A device group can allocate memory across the subdevices, bind memory from one subdevice to a resource on another subdevice, record command buffers where some work executes on an arbitrary subset of the subdevices, and potentially present a swapchain image from one or more subdevices.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_FLAGS_INFO_KHR`

  - `VK_STRUCTURE_TYPE_DEVICE_GROUP_RENDER_PASS_BEGIN_INFO_KHR`

  - `VK_STRUCTURE_TYPE_DEVICE_GROUP_COMMAND_BUFFER_BEGIN_INFO_KHR`

  - `VK_STRUCTURE_TYPE_DEVICE_GROUP_SUBMIT_INFO_KHR`

  - `VK_STRUCTURE_TYPE_DEVICE_GROUP_BIND_SPARSE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_DEVICE_GROUP_PRESENT_CAPABILITIES_KHR`

  - `VK_STRUCTURE_TYPE_IMAGE_SWAPCHAIN_CREATE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_SWAPCHAIN_INFO_KHR`

  - `VK_STRUCTURE_TYPE_ACQUIRE_NEXT_IMAGE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_DEVICE_GROUP_PRESENT_INFO_KHR`

  - `VK_STRUCTURE_TYPE_DEVICE_GROUP_SWAPCHAIN_CREATE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_BIND_BUFFER_MEMORY_DEVICE_GROUP_INFO_KHR`

  - `VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_DEVICE_GROUP_INFO_KHR`

- Extending VkImageCreateFlagBits

  - `VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT_KHR`

- Extending VkPipelineCreateFlagBits

  - `VK_PIPELINE_CREATE_VIEW_INDEX_FROM_DEVICE_INDEX_BIT_KHR`

  - `VK_PIPELINE_CREATE_DISPATCH_BASE_KHR`

- Extending VkDependencyFlagBits

  - `VK_DEPENDENCY_DEVICE_GROUP_BIT_KHR`

- Extending VkSwapchainCreateFlagBitsKHR

  - `VK_SWAPCHAIN_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT_KHR`

#### New Enums

- VkPeerMemoryFeatureFlagBitsKHR

- VkMemoryAllocateFlagBitsKHR

- VkDeviceGroupPresentModeFlagBitsKHR

#### New Structures

- VkMemoryAllocateFlagsInfoKHR

- VkDeviceGroupRenderPassBeginInfoKHR

- VkDeviceGroupCommandBufferBeginInfoKHR

- VkDeviceGroupSubmitInfoKHR

- VkDeviceGroupBindSparseInfoKHR

- VkBindBufferMemoryDeviceGroupInfoKHR

- VkBindImageMemoryDeviceGroupInfoKHR

- VkDeviceGroupPresentCapabilitiesKHR

- VkImageSwapchainCreateInfoKHR

- VkBindImageMemorySwapchainInfoKHR

- VkAcquireNextImageInfoKHR

- VkDeviceGroupPresentInfoKHR

- VkDeviceGroupSwapchainCreateInfoKHR

#### New Functions

- vkGetDeviceGroupPeerMemoryFeaturesKHR

- vkCmdSetDeviceMaskKHR

- vkCmdDispatchBaseKHR

- vkGetDeviceGroupPresentCapabilitiesKHR

- vkGetDeviceGroupSurfacePresentModesKHR

- vkGetPhysicalDevicePresentRectanglesKHR

- vkAcquireNextImage2KHR

#### New Built-In Variables

- `DeviceIndex`

#### New SPIR-V Capabilities

- `DeviceGroup`

#### Promotion to Vulkan 1.1

The following enums, types and commands are included as interactions with `VK_KHR_swapchain`:

- `VK_STRUCTURE_TYPE_DEVICE_GROUP_PRESENT_CAPABILITIES_KHR`

- `VK_STRUCTURE_TYPE_IMAGE_SWAPCHAIN_CREATE_INFO_KHR`

- `VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_SWAPCHAIN_INFO_KHR`

- `VK_STRUCTURE_TYPE_ACQUIRE_NEXT_IMAGE_INFO_KHR`

- `VK_STRUCTURE_TYPE_DEVICE_GROUP_PRESENT_INFO_KHR`

- `VK_STRUCTURE_TYPE_DEVICE_GROUP_SWAPCHAIN_CREATE_INFO_KHR`

- `VK_SWAPCHAIN_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT_KHR`

- VkDeviceGroupPresentModeFlagBitsKHR

- VkDeviceGroupPresentCapabilitiesKHR

- VkImageSwapchainCreateInfoKHR

- VkBindImageMemorySwapchainInfoKHR

- VkAcquireNextImageInfoKHR

- VkDeviceGroupPresentInfoKHR

- VkDeviceGroupSwapchainCreateInfoKHR

- vkGetDeviceGroupPresentCapabilitiesKHR

- vkGetDeviceGroupSurfacePresentModesKHR

- vkGetPhysicalDevicePresentRectanglesKHR

- vkAcquireNextImage2KHR

If Vulkan 1.1 and `VK_KHR_swapchain` are supported, these are included by `VK_KHR_swapchain`.

The base functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

None.

#### Examples

TODO

#### Version History

- Revision 1, 2016-10-19 (Jeff Bolz)

  - Internal revisions

- Revision 2, 2017-05-19 (Tobias Hector)

  - Removed extended memory bind functions to VK_KHR_bind_memory2, added dependency on that extension, and device-group-specific structs for those functions.

- Revision 3, 2017-10-06 (Ian Elliott)

  - Corrected Vulkan 1.1 interactions with the WSI extensions. All Vulkan 1.1 WSI interactions are with the VK_KHR_swapchain extension.

- Revision 4, 2017-10-10 (Jeff Bolz)

  - Rename "SFR" bits and structure members to use the phrase "split instance bind regions".

#### VK_KHR_device_group_creation

Name String

  `VK_KHR_device_group_creation`

Extension Type

  Instance extension

Registered Extension Number

  71

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Promoted to Vulkan 1.1

Contact

  - Jeff Bolz jeffbolznv

Last Modified Date

  2016-10-19

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Promoted to Vulkan 1.1 Core

Contributors

  - Jeff Bolz, NVIDIA

This extension provides instance-level commands to enumerate groups of physical devices, and to create a logical device from a subset of one of those groups. Such a logical device can then be used with new features in the `VK_KHR_device_group` extension.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_GROUP_PROPERTIES_KHR`

  - `VK_STRUCTURE_TYPE_DEVICE_GROUP_DEVICE_CREATE_INFO_KHR`

- Extending VkMemoryHeapFlagBits

  - `VK_MEMORY_HEAP_MULTI_INSTANCE_BIT_KHR`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceGroupPropertiesKHR

- VkDeviceGroupDeviceCreateInfoKHR

#### New Functions

- vkEnumeratePhysicalDeviceGroupsKHR

#### Promotion to Vulkan 1.1

All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

None.

#### Examples

        VkDeviceCreateInfo devCreateInfo = { VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO };
        // (not shown) fill out devCreateInfo as usual.
        uint32_t deviceGroupCount = 0;
        VkPhysicalDeviceGroupPropertiesKHR *props = NULL;

        // Query the number of device groups
        vkEnumeratePhysicalDeviceGroupsKHR(g_vkInstance, &deviceGroupCount, NULL);

        // Allocate and initialize structures to query the device groups
        props = (VkPhysicalDeviceGroupPropertiesKHR *)malloc(deviceGroupCount*sizeof(VkPhysicalDeviceGroupPropertiesKHR));
        for (i = 0; i < deviceGroupCount; ++i) {
            props[i].sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_GROUP_PROPERTIES_KHR;
            props[i].pNext = NULL;
        }
        vkEnumeratePhysicalDeviceGroupsKHR(g_vkInstance, &deviceGroupCount, props);

        // If the first device group has more than one physical device. create
        // a logical device using all of the physical devices.
        VkDeviceGroupDeviceCreateInfoKHR deviceGroupInfo = { VK_STRUCTURE_TYPE_DEVICE_GROUP_DEVICE_CREATE_INFO_KHR };
        if (props[0].physicalDeviceCount > 1) {
            deviceGroupInfo.physicalDeviceCount = props[0].physicalDeviceCount;
            deviceGroupInfo.pPhysicalDevices = props[0].physicalDevices;
            devCreateInfo.pNext = &deviceGroupInfo;
        }

        vkCreateDevice(props[0].physicalDevices[0], &devCreateInfo, NULL, &g_vkDevice);
        free(props);

#### Version History

- Revision 1, 2016-10-19 (Jeff Bolz)

  - Internal revisions

#### VK_KHR_draw_indirect_count

Name String

  `VK_KHR_draw_indirect_count`

Extension Type

  Device extension

Registered Extension Number

  170

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Piers Daniell pdaniell-nv

Last Modified Date

  2017-08-25

Interactions and External Dependencies

  - Promoted to Vulkan 1.2 Core

IP Status

  No known IP claims.

Contributors

  - Matthaeus G. Chajdas, AMD

  - Derrick Owens, AMD

  - Graham Sellers, AMD

  - Daniel Rakos, AMD

  - Dominik Witczak, AMD

  - Piers Daniell, NVIDIA

This extension is based off the `VK_AMD_draw_indirect_count` extension. This extension allows an application to source the number of draw calls for indirect draw calls from a buffer. This enables applications to generate arbitrary amounts of draw commands and execute them without host intervention.

#### New Functions

- vkCmdDrawIndirectCountKHR

- vkCmdDrawIndexedIndirectCountKHR

#### Promotion to Vulkan 1.2

All functionality in this extension is included in core Vulkan 1.2, with the KHR suffix omitted. However, if Vulkan 1.2 is supported and this extension is not, the entry points vkCmdDrawIndirectCount and vkCmdDrawIndexedIndirectCount are optional. The original type, enum and command names are still available as aliases of the core functionality.

#### Version History

- Revision 1, 2017-08-25 (Piers Daniell)

  - Initial draft based off VK_AMD_draw_indirect_count

#### VK_KHR_driver_properties

Name String

  `VK_KHR_driver_properties`

Extension Type

  Device extension

Registered Extension Number

  197

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Daniel Rakos drakos-amd

Last Modified Date

  2018-04-11

Interactions and External Dependencies

  - Promoted to Vulkan 1.2 Core

IP Status

  No known IP claims.

Contributors

  - Baldur Karlsson

  - Matthaeus G. Chajdas, AMD

  - Piers Daniell, NVIDIA

  - Alexander Galazin, Arm

  - Jesse Hall, Google

  - Daniel Rakos, AMD

This extension provides a new physical device query which allows retrieving information about the driver implementation, allowing applications to determine which physical device corresponds to which particular vendor’s driver, and which conformance test suite version the driver implementation is compliant with.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DRIVER_PROPERTIES_KHR`

- `VK_MAX_DRIVER_NAME_SIZE_KHR`

- `VK_MAX_DRIVER_INFO_SIZE_KHR`

#### New Enums

None.

#### New Structures

- VkConformanceVersionKHR

- VkPhysicalDeviceDriverPropertiesKHR

#### New Functions

None.

#### Promotion to Vulkan 1.2

All functionality in this extension is included in core Vulkan 1.2, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

None.

#### Examples

None.

#### Version History

- Revision 1, 2018-04-11 (Daniel Rakos)

  - Internal revisions

#### VK_KHR_external_fence

Name String

  `VK_KHR_external_fence`

Extension Type

  Device extension

Registered Extension Number

  114

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_external_fence_capabilities`

Deprecation state

  - Promoted to Vulkan 1.1

Contact

  - Jesse Hall critsec

Last Modified Date

  2017-05-08

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Promoted to Vulkan 1.1 Core

Contributors

  - Jesse Hall, Google

  - James Jones, NVIDIA

  - Jeff Juliano, NVIDIA

  - Cass Everitt, Oculus

  - Contributors to `VK_KHR_external_semaphore`

An application using external memory may wish to synchronize access to that memory using fences. This extension enables an application to create fences from which non-Vulkan handles that reference the underlying synchronization primitive can be exported.

#### New Object Types

None.

#### New Enum Constants

- `VK_STRUCTURE_TYPE_EXPORT_FENCE_CREATE_INFO_KHR`

#### New Enums

- VkFenceImportFlagBitsKHR

#### New Structs

- VkExportFenceCreateInfoKHR

#### New Functions

None.

#### Promotion to Vulkan 1.1

All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

This extension borrows concepts, semantics, and language from `VK_KHR_external_semaphore`. That extension’s issues apply equally to this extension.

#### Version History

- Revision 1, 2017-05-08 (Jesse Hall)

  - Initial revision

#### VK_KHR_external_fence_capabilities

Name String

  `VK_KHR_external_fence_capabilities`

Extension Type

  Instance extension

Registered Extension Number

  113

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Deprecation state

  - Promoted to Vulkan 1.1

Contact

  - Jesse Hall critsec

Last Modified Date

  2017-05-08

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Promoted to Vulkan 1.1 Core

Contributors

  - Jesse Hall, Google

  - James Jones, NVIDIA

  - Jeff Juliano, NVIDIA

  - Cass Everitt, Oculus

  - Contributors to `VK_KHR_external_semaphore_capabilities`

An application may wish to reference device fences in multiple Vulkan logical devices or instances, in multiple processes, and/or in multiple APIs. This extension provides a set of capability queries and handle definitions that allow an application to determine what types of “external” fence handles an implementation supports for a given set of use cases.

#### New Object Types

None.

#### New Enum Constants

- `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_FENCE_INFO_KHR`

- `VK_STRUCTURE_TYPE_EXTERNAL_FENCE_PROPERTIES_KHR`

- `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_ID_PROPERTIES_KHR`

- `VK_LUID_SIZE_KHR`

#### New Enums

- VkExternalFenceHandleTypeFlagBitsKHR

- VkExternalFenceFeatureFlagBitsKHR

#### New Structs

- VkPhysicalDeviceExternalFenceInfoKHR

- VkExternalFencePropertiesKHR

- VkPhysicalDeviceIDPropertiesKHR

#### New Functions

- vkGetPhysicalDeviceExternalFencePropertiesKHR

#### Promotion to Vulkan 1.1

All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

None.

#### Version History

- Revision 1, 2017-05-08 (Jesse Hall)

  - Initial version

#### VK_KHR_external_memory

Name String

  `VK_KHR_external_memory`

Extension Type

  Device extension

Registered Extension Number

  73

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_external_memory_capabilities`

Deprecation state

  - Promoted to Vulkan 1.1

Contact

  - James Jones cubanismo

Last Modified Date

  2016-10-20

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Interacts with `VK_KHR_dedicated_allocation`.

  - Interacts with `VK_NV_dedicated_allocation`.

  - Promoted to Vulkan 1.1 Core

Contributors

  - Jason Ekstrand, Intel

  - Ian Elliot, Google

  - Jesse Hall, Google

  - Tobias Hector, Imagination Technologies

  - James Jones, NVIDIA

  - Jeff Juliano, NVIDIA

  - Matthew Netsch, Qualcomm Technologies, Inc.

  - Daniel Rakos, AMD

  - Carsten Rohde, NVIDIA

  - Ray Smith, ARM

  - Chad Versace, Google

An application may wish to reference device memory in multiple Vulkan logical devices or instances, in multiple processes, and/or in multiple APIs. This extension enables an application to export non-Vulkan handles from Vulkan memory objects such that the underlying resources can be referenced outside the scope of the Vulkan logical device that created them.

#### New Object Types

None.

#### New Enum Constants

- `VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_BUFFER_CREATE_INFO_KHR`

- `VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_IMAGE_CREATE_INFO_KHR`

- `VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO_KHR`

- `VK_QUEUE_FAMILY_EXTERNAL_KHR`

- `VK_ERROR_INVALID_EXTERNAL_HANDLE_KHR`

#### New Enums

None.

#### New Structs

- VkExternalMemoryImageCreateInfoKHR

- VkExternalMemoryBufferCreateInfoKHR

- VkExportMemoryAllocateInfoKHR

#### New Functions

None.

#### Promotion to Vulkan 1.1

All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

1) How do applications correlate two physical devices across process or Vulkan instance boundaries?

RESOLVED: New device ID fields have been introduced by `VK_KHR_external_memory_capabilities`. These fields, combined with the existing VkPhysicalDeviceProperties::`driverVersion` field can be used to identify compatible devices across processes, drivers, and APIs. VkPhysicalDeviceProperties::`pipelineCacheUUID` is not sufficient for this purpose because despite its description in the specification, it need only identify a unique pipeline cache format in practice. Multiple devices may be able to use the same pipeline cache data, and hence it would be desirable for all of them to have the same pipeline cache UUID. However, only the same concrete physical device can be used when sharing memory, so an actual unique device ID was introduced. Further, the pipeline cache UUID was specific to Vulkan, but correlation with other, non-extensible APIs is required to enable interoperation with those APIs.

2) If memory objects are shared between processes and APIs, is this considered aliasing according to the rules outlined in the Memory Aliasing section?

RESOLVED: Yes. Applications must take care to obey all restrictions imposed on aliased resources when using memory across multiple Vulkan instances or other APIs.

3) Are new image layouts or metadata required to specify image layouts and layout transitions compatible with non-Vulkan APIs, or with other instances of the same Vulkan driver?

RESOLVED: Separate instances of the same Vulkan driver running on the same GPU should have identical internal layout semantics, so applications have the tools they need to ensure views of images are consistent between the two instances. Other APIs will fall into two categories: Those that are Vulkan- compatible, and those that are Vulkan-incompatible. Vulkan-incompatible APIs will require the image to be in the GENERAL layout whenever they are accessing them.

Note this does not attempt to address cross-device transitions, nor transitions to engines on the same device which are not visible within the Vulkan API. Both of these are beyond the scope of this extension.

4) Is a new barrier flag or operation of some type needed to prepare external memory for handoff to another Vulkan instance or API and/or receive it from another instance or API?

RESOLVED: Yes. Some implementations need to perform additional cache management when transitioning memory between address spaces, and other APIs, instances, or processes may operate in a separate address space. Options for defining this transition include:

- A new structure that can be added to the `pNext` list in VkMemoryBarrier, VkBufferMemoryBarrier, and VkImageMemoryBarrier.

- A new bit in VkAccessFlags that can be set to indicate an “external” access.

- A new bit in VkDependencyFlags

- A new special queue family that represents an “external” queue.

A new structure has the advantage that the type of external transition can be described in as much detail as necessary. However, there is not currently a known need for anything beyond differentiating external vs. internal accesses, so this is likely an over-engineered solution. The access flag bit has the advantage that it can be applied at buffer, image, or global granularity, and semantically it maps pretty well to the operation being described. Additionally, the API already includes `VK_ACCESS_MEMORY_READ_BIT` and `VK_ACCESS_MEMORY_WRITE_BIT` which appear to be intended for this purpose. However, there is no obvious pipeline stage that would correspond to an external access, and therefore no clear way to use `VK_ACCESS_MEMORY_READ_BIT` or `VK_ACCESS_MEMORY_WRITE_BIT`. VkDependencyFlags and VkPipelineStageFlags operate at command granularity rather than image or buffer granularity, which would make an entire pipeline barrier an internal→external or external→internal barrier. This may not be a problem in practice, but seems like the wrong scope. Another downside of VkDependencyFlags is that it lacks inherent directionality: There are not `src` and `dst` variants of it in the barrier or dependency description semantics, so two bits might need to be added to describe both internal→external and external→internal transitions. Transitioning a resource to a special queue family corresponds well with the operation of transitioning to a separate Vulkan instance, in that both operations ideally include scheduling a barrier on both sides of the transition: Both the releasing and the acquiring queue or process. Using a special queue family requires adding an additional reserved queue family index. Re-using `VK_QUEUE_FAMILY_IGNORED` would have left it unclear how to transition a concurrent usage resource from one process to another, since the semantics would have likely been equivalent to the currently-ignored transition of `VK_QUEUE_FAMILY_IGNORED` → `VK_QUEUE_FAMILY_IGNORED`. Fortunately, creating a new reserved queue family index is not invasive.

Based on the above analysis, the approach of transitioning to a special “external” queue family was chosen.

5) Do internal driver memory arrangements and/or other internal driver image properties need to be exported and imported when sharing images across processes or APIs.

RESOLVED: Some vendors claim this is necessary on their implementations, but it was determined that the security risks of allowing opaque meta data to be passed from applications to the driver were too high. Therefore, implementations which require metadata will need to associate it with the objects represented by the external handles, and rely on the dedicated allocation mechanism to associate the exported and imported memory objects with a single image or buffer.

6) Most prior interoperation and cross-process sharing APIs have been based on image-level sharing. Should Vulkan sharing be based on memory-object sharing or image sharing?

RESOLVED: These extensions have assumed memory-level sharing is the correct granularity. Vulkan is a lower-level API than most prior APIs, and as such attempts to closely align with to the underlying primitives of the hardware and system-level drivers it abstracts. In general, the resource that holds the backing store for both images and buffers of various types is memory. Images and buffers are merely metadata containing brief descriptions of the layout of bits within that memory.

Because memory object-based sharing is aligned with the overall Vulkan API design, it exposes the full power of Vulkan on external objects. External memory can be used as backing for sparse images, for example, whereas such usage would be awkward at best with a sharing mechanism based on higher-level primitives such as images. Further, aligning the mechanism with the API in this way provides some hope of trivial compatibility with future API enhancements. If new objects backed by memory objects are added to the API, they too can be used across processes with minimal additions to the base external memory APIs.

Earlier APIs implemented interop at a higher level, and this necessitated entirely separate sharing APIs for images and buffers. To co-exist and interoperate with those APIs, the Vulkan external sharing mechanism must accommodate their model. However, if it can be agreed that memory-based sharing is the more desirable and forward-looking design, legacy interoperation considerations can be considered another reason to favor memory-based sharing: While native and legacy driver primitives that may be used to implement sharing may not be as low-level as the API here suggests, raw memory is still the least common denominator among the types. Image-based sharing can be cleanly derived from a set of base memory- object sharing APIs with minimal effort, whereas image-based sharing does not generalize well to buffer or raw-memory sharing. Therefore, following the general Vulkan design principle of minimalism, it is better to expose even interopability with image-based native and external primitives via the memory sharing API, and place sufficient limits on their usage to ensure they can be used only as backing for equivalent Vulkan images. This provides a consistent API for applications regardless of which platform or external API they are targeting, which makes development of multi-API and multi-platform applications simpler.

7) Should Vulkan define a common external handle type and provide Vulkan functions to facilitate cross-process sharing of such handles rather than relying on native handles to define the external objects?

RESOLVED: No. Cross-process sharing of resources is best left to native platforms. There are myriad security and extensibility issues with such a mechanism, and attempting to re-solve all those issues within Vulkan does not align with Vulkan’s purpose as a graphics API. If desired, such a mechanism could be built as a layer or helper library on top of the opaque native handle defined in this family of extensions.

8) Must implementations provide additional guarantees about state implicitly included in memory objects for those memory objects that may be exported?

RESOLVED: Implementations must ensure that sharing memory objects does not transfer any information between the exporting and importing instances and APIs other than that required to share the data contained in the memory objects explicitly shared. As specific examples, data from previously freed memory objects that used the same underlying physical memory, and data from memory obects using adjacent physical memory must not be visible to applications importing an exported memory object.

9) Must implementations validate external handles the application provides as input to memory import operations?

RESOLVED: Implementations must return an error to the application if the provided memory handle cannot be used to complete the requested import operation. However, implementations need not validate handles are of the exact type specified by the application.

#### Version History

- Revision 1, 2016-10-20 (James Jones)

  - Initial version

#### VK_KHR_external_memory_capabilities

Name String

  `VK_KHR_external_memory_capabilities`

Extension Type

  Instance extension

Registered Extension Number

  72

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Deprecation state

  - Promoted to Vulkan 1.1

Contact

  - James Jones cubanismo

Last Modified Date

  2016-10-17

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Interacts with `VK_KHR_dedicated_allocation`.

  - Interacts with `VK_NV_dedicated_allocation`.

  - Promoted to Vulkan 1.1 Core

Contributors

  - Ian Elliot, Google

  - Jesse Hall, Google

  - James Jones, NVIDIA

An application may wish to reference device memory in multiple Vulkan logical devices or instances, in multiple processes, and/or in multiple APIs. This extension provides a set of capability queries and handle definitions that allow an application to determine what types of “external” memory handles an implementation supports for a given set of use cases.

#### New Object Types

None.

#### New Enum Constants

- `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_IMAGE_FORMAT_INFO_KHR`

- `VK_STRUCTURE_TYPE_EXTERNAL_IMAGE_FORMAT_PROPERTIES_KHR`

- `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_BUFFER_INFO_KHR`

- `VK_STRUCTURE_TYPE_EXTERNAL_BUFFER_PROPERTIES_KHR`

- `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_ID_PROPERTIES_KHR`

- `VK_LUID_SIZE_KHR`

#### New Enums

- VkExternalMemoryHandleTypeFlagBitsKHR

- VkExternalMemoryFeatureFlagBitsKHR

#### New Structs

- VkExternalMemoryPropertiesKHR

- VkPhysicalDeviceExternalImageFormatInfoKHR

- VkExternalImageFormatPropertiesKHR

- VkPhysicalDeviceExternalBufferInfoKHR

- VkExternalBufferPropertiesKHR

- VkPhysicalDeviceIDPropertiesKHR

#### New Functions

- vkGetPhysicalDeviceExternalBufferPropertiesKHR

#### Promotion to Vulkan 1.1

All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

1) Why do so many external memory capabilities need to be queried on a per-memory-handle-type basis?

PROPOSED RESOLUTION: This is because some handle types are based on OS-native objects that have far more limited capabilities than the very generic Vulkan memory objects. Not all memory handle types can name memory objects that support 3D images, for example. Some handle types cannot even support the deferred image and memory binding behavior of Vulkan and require specifying the image when allocating or importing the memory object.

2) Do the VkExternalImageFormatPropertiesKHR and VkExternalBufferPropertiesKHR structs need to include a list of memory type bits that support the given handle type?

PROPOSED RESOLUTION: No. The memory types that don’t support the handle types will simply be filtered out of the results returned by vkGetImageMemoryRequirements and vkGetBufferMemoryRequirements when a set of handle types was specified at image or buffer creation time.

3) Should the non-opaque handle types be moved to their own extension?

PROPOSED RESOLUTION: Perhaps. However, defining the handle type bits does very little and does not require any platform-specific types on its own, and it’s easier to maintain the bitfield values in a single extension for now. Presumably more handle types could be added by separate extensions though, and it would be midly weird to have some platform-specific ones defined in the core spec and some in extensions

4) Do we need a `D3D11_TILEPOOL` type?

PROPOSED RESOLUTION: No. This is technically possible, but the synchronization is awkward. D3D11 surfaces must be synchronized using shared mutexes, and these synchronization primitives are shared by the entire memory object, so D3D11 shared allocations divided among multiple buffer and image bindings may be difficult to synchronize.

5) Should the Windows 7-compatible handle types be named “KMT” handles or “GLOBAL_SHARE” handles?

PROPOSED RESOLUTION: KMT, simply because it is more concise.

6) How do applications identify compatible devices and drivers across instance, process, and API boundaries when sharing memory?

PROPOSED RESOLUTION: New device properties are exposed that allow applications to correctly correlate devices and drivers. A device and driver UUID that must both match to ensure sharing compatibility between two Vulkan instances, or a Vulkan instance and an extensible external API are added. To allow correlating with Direct3D devices, a device LUID is added that corresponds to a DXGI adapter LUID. A driver ID is not needed for Direct3D because mismatched driver component versions are not a currently supported configuration on the Windows OS. Should support for such configurations be introduced at the OS level, further Vulkan extensions would be needed to correlate userspace component builds.

#### Version History

- Revision 1, 2016-10-17 (James Jones)

  - Initial version

#### VK_KHR_external_semaphore

Name String

  `VK_KHR_external_semaphore`

Extension Type

  Device extension

Registered Extension Number

  78

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_external_semaphore_capabilities`

Deprecation state

  - Promoted to Vulkan 1.1

Contact

  - James Jones cubanismo

Last Modified Date

  2016-10-21

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Promoted to Vulkan 1.1 Core

Contributors

  - Jason Ekstrand, Intel

  - Jesse Hall, Google

  - Tobias Hector, Imagination Technologies

  - James Jones, NVIDIA

  - Jeff Juliano, NVIDIA

  - Matthew Netsch, Qualcomm Technologies, Inc.

  - Ray Smith, ARM

  - Chad Versace, Google

An application using external memory may wish to synchronize access to that memory using semaphores. This extension enables an application to create semaphores from which non-Vulkan handles that reference the underlying synchronization primitive can be exported.

#### New Object Types

None.

#### New Enum Constants

- `VK_STRUCTURE_TYPE_EXPORT_SEMAPHORE_CREATE_INFO_KHR`

- `VK_ERROR_INVALID_EXTERNAL_HANDLE_KHR`

#### New Enums

- VkSemaphoreImportFlagBitsKHR

#### New Structs

- VkExportSemaphoreCreateInfoKHR

#### New Functions

None.

#### Promotion to Vulkan 1.1

All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

1) Should there be restrictions on what side effects can occur when waiting on imported semaphores that are in an invalid state?

RESOLVED: Yes. Normally, validating such state would be the responsibility of the application, and the implementation would be free to enter an undefined state if valid usage rules were violated. However, this could cause security concerns when using imported semaphores, as it would require the importing application to trust the exporting application to ensure the state is valid. Requiring this level of trust is undesirable for many potential use cases.

2) Must implementations validate external handles the application provides as input to semaphore state import operations?

RESOLVED: Implementations must return an error to the application if the provided semaphore state handle cannot be used to complete the requested import operation. However, implementations need not validate handles are of the exact type specified by the application.

#### Version History

- Revision 1, 2016-10-21 (James Jones)

  - Initial revision

#### VK_KHR_external_semaphore_capabilities

Name String

  `VK_KHR_external_semaphore_capabilities`

Extension Type

  Instance extension

Registered Extension Number

  77

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Deprecation state

  - Promoted to Vulkan 1.1

Contact

  - James Jones cubanismo

Last Modified Date

  2016-10-20

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Promoted to Vulkan 1.1 Core

Contributors

  - Jesse Hall, Google

  - James Jones, NVIDIA

  - Jeff Juliano, NVIDIA

An application may wish to reference device semaphores in multiple Vulkan logical devices or instances, in multiple processes, and/or in multiple APIs. This extension provides a set of capability queries and handle definitions that allow an application to determine what types of “external” semaphore handles an implementation supports for a given set of use cases.

#### New Object Types

None.

#### New Enum Constants

- `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_EXTERNAL_SEMAPHORE_INFO_KHR`

- `VK_STRUCTURE_TYPE_EXTERNAL_SEMAPHORE_PROPERTIES_KHR`

- `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_ID_PROPERTIES_KHR`

- `VK_LUID_SIZE_KHR`

#### New Enums

- VkExternalSemaphoreHandleTypeFlagBitsKHR

- VkExternalSemaphoreFeatureFlagBitsKHR

#### New Structs

- VkPhysicalDeviceExternalSemaphoreInfoKHR

- VkExternalSemaphorePropertiesKHR

- VkPhysicalDeviceIDPropertiesKHR

#### New Functions

- vkGetPhysicalDeviceExternalSemaphorePropertiesKHR

#### Promotion to Vulkan 1.1

All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

#### Version History

- Revision 1, 2016-10-20 (James Jones)

  - Initial revision

#### VK_KHR_get_memory_requirements2

Name String

  `VK_KHR_get_memory_requirements2`

Extension Type

  Device extension

Registered Extension Number

  147

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Promoted to Vulkan 1.1

Contact

  - Jason Ekstrand jekstrand

Last Modified Date

  2017-09-05

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Promoted to Vulkan 1.1 Core

Contributors

  - Jason Ekstrand, Intel

  - Jeff Bolz, NVIDIA

  - Jesse Hall, Google

This extension provides new entry points to query memory requirements of images and buffers in a way that can be easily extended by other extensions, without introducing any further entry points. The Vulkan 1.0 VkMemoryRequirements and VkSparseImageMemoryRequirements structures do not include `sType` and `pNext` members. This extension wraps them in new structures with these members, so an application can query a chain of memory requirements structures by constructing the chain and letting the implementation fill them in. A new command is added for each `vkGet*MemoryRequrements` command in core Vulkan 1.0.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_BUFFER_MEMORY_REQUIREMENTS_INFO_2_KHR`

  - `VK_STRUCTURE_TYPE_IMAGE_MEMORY_REQUIREMENTS_INFO_2_KHR`

  - `VK_STRUCTURE_TYPE_IMAGE_SPARSE_MEMORY_REQUIREMENTS_INFO_2_KHR`

  - `VK_STRUCTURE_TYPE_MEMORY_REQUIREMENTS_2_KHR`

  - `VK_STRUCTURE_TYPE_SPARSE_IMAGE_MEMORY_REQUIREMENTS_2_KHR`

#### New Enums

None.

#### New Structures

- VkBufferMemoryRequirementsInfo2KHR

- VkImageMemoryRequirementsInfo2KHR

- VkImageSparseMemoryRequirementsInfo2KHR

- VkMemoryRequirements2KHR

- VkSparseImageMemoryRequirements2KHR

#### New Functions

- vkGetImageMemoryRequirements2KHR

- vkGetBufferMemoryRequirements2KHR

- vkGetImageSparseMemoryRequirements2KHR

#### Promotion to Vulkan 1.1

All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

None.

#### Version History

- Revision 1, 2017-03-23 (Jason Ekstrand)

  - Internal revisions

#### VK_KHR_get_physical_device_properties2

Name String

  `VK_KHR_get_physical_device_properties2`

Extension Type

  Instance extension

Registered Extension Number

  60

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Promoted to Vulkan 1.1

Contact

  - Jeff Bolz jeffbolznv

Last Modified Date

  2017-09-05

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Promoted to Vulkan 1.1 Core

Contributors

  - Jeff Bolz, NVIDIA

  - Ian Elliott, Google

This extension provides new entry points to query device features, device properties, and format properties in a way that can be easily extended by other extensions, without introducing any further entry points. The Vulkan 1.0 feature/limit/formatproperty structures do not include `sType`/`pNext` members. This extension wraps them in new structures with `sType`/`pNext` members, so an application can query a chain of feature/limit/formatproperty structures by constructing the chain and letting the implementation fill them in. A new command is added for each `vkGetPhysicalDevice*` command in core Vulkan 1.0. The new feature structure (and a chain of extension structures) can also be passed in to device creation to enable features.

This extension also allows applications to use the physical-device components of device extensions before vkCreateDevice is called.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FEATURES_2_KHR`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROPERTIES_2_KHR`

  - `VK_STRUCTURE_TYPE_FORMAT_PROPERTIES_2_KHR`

  - `VK_STRUCTURE_TYPE_IMAGE_FORMAT_PROPERTIES_2_KHR`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGE_FORMAT_INFO_2_KHR`

  - `VK_STRUCTURE_TYPE_QUEUE_FAMILY_PROPERTIES_2_KHR`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MEMORY_PROPERTIES_2_KHR`

  - `VK_STRUCTURE_TYPE_SPARSE_IMAGE_FORMAT_PROPERTIES_2_KHR`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SPARSE_IMAGE_FORMAT_INFO_2_KHR`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceFeatures2KHR

- VkPhysicalDeviceProperties2KHR

- VkFormatProperties2KHR

- VkImageFormatProperties2KHR

- VkPhysicalDeviceImageFormatInfo2KHR

- VkQueueFamilyProperties2KHR

- VkPhysicalDeviceMemoryProperties2KHR

- VkSparseImageFormatProperties2KHR

- VkPhysicalDeviceSparseImageFormatInfo2KHR

#### New Functions

- vkGetPhysicalDeviceFeatures2KHR

- vkGetPhysicalDeviceProperties2KHR

- vkGetPhysicalDeviceFormatProperties2KHR

- vkGetPhysicalDeviceImageFormatProperties2KHR

- vkGetPhysicalDeviceQueueFamilyProperties2KHR

- vkGetPhysicalDeviceMemoryProperties2KHR

- vkGetPhysicalDeviceSparseImageFormatProperties2KHR

#### Promotion to Vulkan 1.1

All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

None.

#### Examples

        // Get features with a hypothetical future extension.
        VkHypotheticalExtensionFeaturesKHR hypotheticalFeatures =
        {
            VK_STRUCTURE_TYPE_HYPOTHETICAL_FEATURES_KHR,                            // sType
            NULL,                                                                   // pNext
        };

        VkPhysicalDeviceFeatures2KHR features =
        {
            VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FEATURES_2_KHR,                       // sType
            &hypotheticalFeatures,                                                  // pNext
        };

        // After this call, features and hypotheticalFeatures have been filled out.
        vkGetPhysicalDeviceFeatures2KHR(physicalDevice, &features);

        // Properties/limits can be chained and queried similarly.

        // Enable some features:
        VkHypotheticalExtensionFeaturesKHR enabledHypotheticalFeatures =
        {
            VK_STRUCTURE_TYPE_HYPOTHETICAL_FEATURES_KHR,                            // sType
            NULL,                                                                   // pNext
        };

        VkPhysicalDeviceFeatures2KHR enabledFeatures =
        {
            VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FEATURES_2_KHR,                       // sType
            &enabledHypotheticalFeatures,                                           // pNext
        };

        enabledFeatures.features.xyz = VK_TRUE;
        enabledHypotheticalFeatures.abc = VK_TRUE;

        VkDeviceCreateInfo deviceCreateInfo =
        {
            VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO,                                   // sType
            &enabledFeatures,                                                       // pNext
            ...
            NULL,                                                                   // pEnabledFeatures
        }

        VkDevice device;
        vkCreateDevice(physicalDevice, &deviceCreateInfo, NULL, &device);

#### Version History

- Revision 1, 2016-09-12 (Jeff Bolz)

  - Internal revisions

- Revision 2, 2016-11-02 (Ian Elliott)

  - Added ability for applications to use the physical-device components of device extensions before vkCreateDevice is called.

#### VK_KHR_image_format_list

Name String

  `VK_KHR_image_format_list`

Extension Type

  Device extension

Registered Extension Number

  148

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Jason Ekstrand jekstrand

Last Modified Date

  2017-03-20

Interactions and External Dependencies

  - Promoted to Vulkan 1.2 Core

IP Status

  No known IP claims.

Contributors

  - Jason Ekstrand, Intel

  - Jan-Harald Fredriksen, ARM

  - Jeff Bolz, NVIDIA

  - Jeff Leger, Qualcomm

  - Neil Henning, Codeplay

On some implementations, setting the `VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT` on image creation can cause access to that image to perform worse than an equivalent image created without `VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT` because the implementation does not know what view formats will be paired with the image.

This extension allows an application to provide the list of all formats that can be used with an image when it is created. The implementation may then be able to create a more efficient image that supports the subset of formats required by the application without having to support all formats in the format compatibility class of the image format.

#### New Object Types

None.

#### New Enum Constants

- `VK_STRUCTURE_TYPE_IMAGE_FORMAT_LIST_CREATE_INFO_KHR`

#### New Enums

None.

#### New Structs

- VkImageFormatListCreateInfoKHR

#### New Functions

None.

#### Promotion to Vulkan 1.2

All functionality in this extension is included in core Vulkan 1.2, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

#### Version History

- Revision 1, 2017-03-20 (Jason Ekstrand)

  - Initial revision

#### VK_KHR_imageless_framebuffer

Name String

  `VK_KHR_imageless_framebuffer`

Extension Type

  Device extension

Registered Extension Number

  109

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_maintenance2`

  - Requires `VK_KHR_image_format_list`

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Tobias Hector tobias

Last Modified Date

  2018-12-14

Interactions and External Dependencies

  - Promoted to Vulkan 1.2 Core

Contributors

  - Tobias Hector

  - Graham Wihlidal

This extension allows framebuffers to be created without the need for creating images first, allowing more flexibility in how they are used, and avoiding the need for many of the confusing compatibility rules.

Framebuffers are now created with a small amount of additional metadata about the image views that will be used in VkFramebufferAttachmentsCreateInfoKHR, and the actual image views are provided at render pass begin time via VkRenderPassAttachmentBeginInfoKHR.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGELESS_FRAMEBUFFER_FEATURES_KHR`

  - `VK_STRUCTURE_TYPE_FRAMEBUFFER_ATTACHMENTS_CREATE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_FRAMEBUFFER_ATTACHMENT_IMAGE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_RENDER_PASS_ATTACHMENT_BEGIN_INFO_KHR`

- Extending VkFramebufferCreateFlagBits:

  - `VK_FRAMEBUFFER_CREATE_IMAGELESS_BIT_KHR`

#### New Structures

- VkPhysicalDeviceImagelessFramebufferFeaturesKHR

- VkFramebufferAttachmentsCreateInfoKHR

- VkFramebufferAttachmentImageInfoKHR

- VkRenderPassAttachmentBeginInfoKHR

#### Promotion to Vulkan 1.2

All functionality in this extension is included in core Vulkan 1.2, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Version History

- Revision 1, 2018-12-14 (Tobias Hector)

  - Internal revisions

#### VK_KHR_maintenance1

Name String

  `VK_KHR_maintenance1`

Extension Type

  Device extension

Registered Extension Number

  70

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Promoted to Vulkan 1.1

Contact

  - Piers Daniell pdaniell-nv

Last Modified Date

  2018-03-13

Interactions and External Dependencies

  - Promoted to Vulkan 1.1 Core

Contributors

  - Dan Ginsburg, Valve

  - Daniel Koch, NVIDIA

  - Daniel Rakos, AMD

  - Jan-Harald Fredriksen, ARM

  - Jason Ekstrand, Intel

  - Jeff Bolz, NVIDIA

  - Jesse Hall, Google

  - John Kessenich, Google

  - Michael Worcester, Imagination Technologies

  - Neil Henning, Codeplay Software Ltd.

  - Piers Daniell, NVIDIA

  - Slawomir Grajewski, Intel

  - Tobias Hector, Imagination Technologies

  - Tom Olson, ARM

`VK_KHR_maintenance1` adds a collection of minor features that were intentionally left out or overlooked from the original Vulkan 1.0 release.

The new features are as follows:

- Allow 2D and 2D array image views to be created from 3D images, which can then be used as color framebuffer attachments. This allows applications to render to slices of a 3D image.

- Support vkCmdCopyImage between 2D array layers and 3D slices. This extension allows copying from layers of a 2D array image to slices of a 3D image and vice versa.

- Allow negative height to be specified in the VkViewport::`height` field to perform y-inversion of the clip-space to framebuffer-space transform. This allows apps to avoid having to use `gl_Position.y = -gl_Position.y` in shaders also targeting other APIs.

- Allow implementations to express support for doing just transfers and clears of image formats that they otherwise support no other format features for. This is done by adding new format feature flags `VK_FORMAT_FEATURE_TRANSFER_SRC_BIT_KHR` and `VK_FORMAT_FEATURE_TRANSFER_DST_BIT_KHR`.

- Support vkCmdFillBuffer on transfer-only queues. Previously vkCmdFillBuffer was defined to only work on command buffers allocated from command pools which support graphics or compute queues. It is now allowed on queues that just support transfer operations.

- Fix the inconsistency of how error conditions are returned between the vkCreateGraphicsPipelines and vkCreateComputePipelines functions and the vkAllocateDescriptorSets and vkAllocateCommandBuffers functions.

- Add new `VK_ERROR_OUT_OF_POOL_MEMORY_KHR` error so implementations can give a more precise reason for vkAllocateDescriptorSets failures.

- Add a new command vkTrimCommandPoolKHR which gives the implementation an opportunity to release any unused command pool memory back to the system.

#### New Object Types

None.

#### New Enum Constants

- `VK_ERROR_OUT_OF_POOL_MEMORY_KHR`

- `VK_FORMAT_FEATURE_TRANSFER_SRC_BIT_KHR`

- `VK_FORMAT_FEATURE_TRANSFER_DST_BIT_KHR`

- `VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT_KHR`

#### New Enums

None.

#### New Structures

None.

#### New Functions

- vkTrimCommandPoolKHR

#### Promotion to Vulkan 1.1

All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

1. Are viewports with zero height allowed?

   RESOLVED: Yes, although they have low utility.

#### Version History

- Revision 1, 2016-10-26 (Piers Daniell)

  - Internal revisions

- Revision 2, 2018-03-13 (Jon Leech)

  - Add issue for zero-height viewports

#### VK_KHR_maintenance2

Name String

  `VK_KHR_maintenance2`

Extension Type

  Device extension

Registered Extension Number

  118

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Promoted to Vulkan 1.1

Contact

  - Michael Worcester michaelworcester

Last Modified Date

  2017-09-05

Interactions and External Dependencies

  - Promoted to Vulkan 1.1 Core

Contributors

  - Michael Worcester, Imagination Technologies

  - Stuart Smith, Imagination Technologies

  - Jeff Bolz, NVIDIA

  - Daniel Koch, NVIDIA

  - Jan-Harald Fredriksen, ARM

  - Daniel Rakos, AMD

  - Neil Henning, Codeplay

  - Piers Daniell, NVIDIA

`VK_KHR_maintenance2` adds a collection of minor features that were intentionally left out or overlooked from the original Vulkan 1.0 release.

The new features are as follows:

- Allow the application to specify which aspect of an input attachment might be read for a given subpass.

- Allow implementations to express the clipping behavior of points.

- Allow creating images with usage flags that may not be supported for the base image’s format, but are supported for image views of the image that have a different but compatible format.

- Allow creating uncompressed image views of compressed images.

- Allow the application to select between an upper-left and lower-left origin for the tessellation domain space.

- Adds two new image layouts for depth stencil images to allow either the depth or stencil aspect to be read-only while the other aspect is writable.

#### Input Attachment Specification

Input attachment specification allows an application to specify which aspect of a multi-aspect image (e.g. a combined depth stencil format) will be accessed via a `subpassLoad` operation.

On some implementations there may be a performance penalty if the implementation does not know (at vkCreateRenderPass time) which aspect(s) of multi-aspect images can be accessed as input attachments.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_RENDER_PASS_INPUT_ATTACHMENT_ASPECT_CREATE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_POINT_CLIPPING_PROPERTIES_KHR`

  - `VK_STRUCTURE_TYPE_IMAGE_VIEW_USAGE_CREATE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_PIPELINE_TESSELLATION_DOMAIN_ORIGIN_STATE_CREATE_INFO_KHR`

- Extending VkImageCreateFlagBits:

  - `VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT_KHR`

  - `VK_IMAGE_CREATE_EXTENDED_USAGE_BIT_KHR`

- Extending VkImageLayout

  - `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL_KHR`

  - `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL_KHR`

- `VK_POINT_CLIPPING_BEHAVIOR_ALL_CLIP_PLANES_KHR`

- `VK_POINT_CLIPPING_BEHAVIOR_USER_CLIP_PLANES_ONLY_KHR`

#### New Enums

- VkPointClippingBehaviorKHR

- VkTessellationDomainOriginKHR

#### New Structures

- VkPhysicalDevicePointClippingPropertiesKHR

- VkRenderPassInputAttachmentAspectCreateInfoKHR

- VkInputAttachmentAspectReferenceKHR

- VkImageViewUsageCreateInfoKHR

- VkPipelineTessellationDomainOriginStateCreateInfoKHR

#### New Functions

None.

#### Promotion to Vulkan 1.1

All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Input Attachment Specification Example

Consider the case where a render pass has two subpasses and two attachments.

Attachment 0 has the format `VK_FORMAT_D24_UNORM_S8_UINT`, attachment 1 has some color format.

Subpass 0 writes to attachment 0, subpass 1 reads only the depth information from attachment 0 (using inputAttachmentRead) and writes to attachment 1.

        VkInputAttachmentAspectReferenceKHR references[] = {
            {
                .subpass = 1,
                .inputAttachmentIndex = 0,
                .aspectMask = VK_IMAGE_ASPECT_DEPTH_BIT
            }
        };

        VkRenderPassInputAttachmentAspectCreateInfoKHR specifyAspects = {
            .sType = VK_STRUCTURE_TYPE_RENDER_PASS_INPUT_ATTACHMENT_ASPECT_CREATE_INFO_KHR,
            .pNext = NULL,
            .aspectReferenceCount = 1,
            .pAspectReferences = references
        };

        VkRenderPassCreateInfo createInfo = {
            ...
            .pNext = &specifyAspects,
            ...
        }

        vkCreateRenderPass(...);

#### Issues

1) What is the default tessellation domain origin?

RESOLVED: Vulkan 1.0 originally inadvertently documented a lower-left origin, but the conformance tests and all implementations implemented an upper-left origin. This extension adds a control to select between lower-left (for compatibility with OpenGL) and upper-left, and we retroactively fix unextended Vulkan to have a default of an upper-left origin.

#### Version History

- Revision 1, 2017-04-28

#### VK_KHR_maintenance3

Name String

  `VK_KHR_maintenance3`

Extension Type

  Device extension

Registered Extension Number

  169

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Deprecation state

  - Promoted to Vulkan 1.1

Contact

  - Jeff Bolz jeffbolznv

Status

  Draft

Last Modified Date

  2017-09-05

Interactions and External Dependencies

  - Promoted to Vulkan 1.1 Core

Contributors

  - Jeff Bolz, NVIDIA

`VK_KHR_maintenance3` adds a collection of minor features that were intentionally left out or overlooked from the original Vulkan 1.0 release.

The new features are as follows:

- A limit on the maximum number of descriptors that are supported in a single descriptor set layout. Some implementations have a limit on the total size of descriptors in a set, which cannot be expressed in terms of the limits in Vulkan 1.0.

- A limit on the maximum size of a single memory allocation. Some platforms have kernel interfaces that limit the maximum size of an allocation.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MAINTENANCE_3_PROPERTIES_KHR`

  - `VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_SUPPORT_KHR`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceMaintenance3PropertiesKHR

- VkDescriptorSetLayoutSupportKHR

#### New Functions

- vkGetDescriptorSetLayoutSupportKHR

#### Promotion to Vulkan 1.1

All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

None.

#### Version History

- Revision 1, 2017-08-22

#### VK_KHR_multiview

Name String

  `VK_KHR_multiview`

Extension Type

  Device extension

Registered Extension Number

  54

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Deprecation state

  - Promoted to Vulkan 1.1

Contact

  - Jeff Bolz jeffbolznv

Last Modified Date

  2016-10-28

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Promoted to Vulkan 1.1 Core

  - Requires the `SPV_KHR_multiview` SPIR-V extension.

  - Requires `GL_EXT_multiview` for GLSL source languages.

Contributors

  - Jeff Bolz, NVIDIA

This extension has the same goal as the OpenGL ES `GL_OVR_multiview` extension - it enables rendering to multiple “views” by recording a single set of commands to be executed with slightly different behavior for each view. It includes a concise way to declare a render pass with multiple views, and gives implementations freedom to render the views in the most efficient way possible.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_RENDER_PASS_MULTIVIEW_CREATE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_FEATURES_KHR`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_PROPERTIES_KHR`

- Extending VkDependencyFlagBits

  - `VK_DEPENDENCY_VIEW_LOCAL_BIT_KHR`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceMultiviewFeaturesKHR

- VkPhysicalDeviceMultiviewPropertiesKHR

- VkRenderPassMultiviewCreateInfoKHR

#### New Functions

None.

#### New Built-In Variables

- `ViewIndex`

#### New SPIR-V Capabilities

- `MultiView`

#### Promotion to Vulkan 1.1

All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

None.

#### Examples

None.

#### Version History

- Revision 1, 2016-10-28 (Jeff Bolz)

  - Internal revisions

#### VK_KHR_relaxed_block_layout

Name String

  `VK_KHR_relaxed_block_layout`

Extension Type

  Device extension

Registered Extension Number

  145

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Promoted to Vulkan 1.1

Contact

  - John Kessenich johnkslang

Last Modified Date

  2017-03-26

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Promoted to Vulkan 1.1 Core

Contributors

  - John Kessenich, Google

The `VK_KHR_relaxed_block_layout` extension allows implementations to indicate they can support more variation in block `Offset` decorations. For example, placing a vector of three floats at an offset of 16×N + 4.

See Offset and Stride Assignment for details.

#### Promotion to Vulkan 1.1

All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Version History

- Revision 1, 2017-03-26 (JohnK)

#### VK_KHR_sampler_mirror_clamp_to_edge

Name String

  `VK_KHR_sampler_mirror_clamp_to_edge`

Extension Type

  Device extension

Registered Extension Number

  15

Revision

  3

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Tobias Hector tobski

Last Modified Date

  2019-08-17

Interactions and External Dependencies

  - Promoted to Vulkan 1.2 Core

Contributors

  - Tobias Hector, Imagination Technologies

  - Jon Leech, Khronos

`VK_KHR_sampler_mirror_clamp_to_edge` extends the set of sampler address modes to include an additional mode (`VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE`) that effectively uses a texture map twice as large as the original image in which the additional half of the new image is a mirror image of the original image.

This new mode relaxes the need to generate images whose opposite edges match by using the original image to generate a matching “mirror image”. This mode allows the texture to be mirrored only once in the negative s, t, and r directions.

#### New Enum Constants

- Extending VkSamplerAddressMode:

  - `VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE`

#### Promotion to Vulkan 1.2

All functionality in this extension is included in core Vulkan 1.2. However, if Vulkan 1.2 is supported and this extension is not, the VkSamplerAddressMode `VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE` is optional. Since the original extension did not use an author suffix on the enum `VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE`, it is used by both core and extension implementations.

#### Example

Creating a sampler with the new address mode in each dimension

        VkSamplerCreateInfo createInfo =
        {
            VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO // sType
            // Other members set to application-desired values
        };

        createInfo.addressModeU = VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE;
        createInfo.addressModeV = VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE;
        createInfo.addressModeW = VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE;

        VkSampler sampler;
        VkResult result = vkCreateSampler(
            device,
            &createInfo,
            &sampler);

#### Issues

1) Why are both KHR and core versions of the `VK_SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE` token present?

RESOLVED: This functionality was intended to be required in Vulkan 1.0. We realized shortly before public release that not all implementations could support it, and moved the functionality into an optional extension, but did not apply the KHR extension suffix. Adding a KHR-suffixed alias of the non-suffixed enum has been done to comply with our own naming rules.

In a related change, before spec revision 1.1.121 this extension was hardwiring into the spec Makefile so it was always included with the Specification, even in the core-only versions. This has now been reverted, and it is treated as any other extension.

#### Version History

- Revision 1, 2016-02-16 (Tobias Hector)

  - Initial draft

- Revision 2, 2019-08-14 (Jon Leech)

  - Add KHR-suffixed alias of non-suffixed enum.

- Revision 3, 2019-08-17 (Jon Leech)

  - Add an issue explaining the reason for the extension API not being suffixed with KHR.

#### VK_KHR_sampler_ycbcr_conversion

Name String

  `VK_KHR_sampler_ycbcr_conversion`

Extension Type

  Device extension

Registered Extension Number

  157

Revision

  14

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_maintenance1`

  - Requires `VK_KHR_bind_memory2`

  - Requires `VK_KHR_get_memory_requirements2`

  - Requires `VK_KHR_get_physical_device_properties2`

Deprecation state

  - Promoted to Vulkan 1.1

Contact

  - Andrew Garrard fluppeteer

Last Modified Date

  2017-08-11

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Promoted to Vulkan 1.1 Core

Contributors

  - Andrew Garrard, Samsung Electronics

  - Tobias Hector, Imagination Technologies

  - James Jones, NVIDIA

  - Daniel Koch, NVIDIA

  - Daniel Rakos, AMD

  - Romain Guy, Google

  - Jesse Hall, Google

  - Tom Cooksey, ARM Ltd

  - Jeff Leger, Qualcomm Technologies, Inc

  - Jan-Harald Fredriksen, ARM Ltd

  - Jan Outters, Samsung Electronics

  - Alon Or-bach, Samsung Electronics

  - Michael Worcester, Imagination Technologies

  - Jeff Bolz, NVIDIA

  - Tony Zlatinski, NVIDIA

  - Matthew Netsch, Qualcomm Technologies, Inc

This extension provides the ability to perform specified color space conversions during texture sampling operations. It also adds a selection of multi-planar formats, including the ability to bind memory to the planes of an image collectively or separately.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_CREATE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_SAMPLER_YCBCR_CONVERSION_INFO_KHR`

  - `VK_STRUCTURE_TYPE_BIND_IMAGE_PLANE_MEMORY_INFO_KHR`

  - `VK_STRUCTURE_TYPE_IMAGE_PLANE_MEMORY_REQUIREMENTS_INFO_KHR`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SAMPLER_YCBCR_CONVERSION_FEATURES_KHR`

- Extending VkFormat:

  - `VK_FORMAT_G8B8G8R8_422_UNORM_KHR`

  - `VK_FORMAT_B8G8R8G8_422_UNORM_KHR`

  - `VK_FORMAT_G8_B8_R8_3PLANE_420_UNORM_KHR`

  - `VK_FORMAT_G8_B8R8_2PLANE_420_UNORM_KHR`

  - `VK_FORMAT_G8_B8_R8_3PLANE_422_UNORM_KHR`

  - `VK_FORMAT_G8_B8R8_2PLANE_422_UNORM_KHR`

  - `VK_FORMAT_G8_B8_R8_3PLANE_444_UNORM_KHR`

  - `VK_FORMAT_R10X6_UNORM_PACK16_KHR`

  - `VK_FORMAT_R10X6G10X6_UNORM_2PACK16_KHR`

  - `VK_FORMAT_R10X6G10X6B10X6A10X6_UNORM_4PACK16_KHR`

  - `VK_FORMAT_G10X6B10X6G10X6R10X6_422_UNORM_4PACK16_KHR`

  - `VK_FORMAT_B10X6G10X6R10X6G10X6_422_UNORM_4PACK16_KHR`

  - `VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_420_UNORM_3PACK16_KHR`

  - `VK_FORMAT_G10X6_B10X6R10X6_2PLANE_420_UNORM_3PACK16_KHR`

  - `VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_422_UNORM_3PACK16_KHR`

  - `VK_FORMAT_G10X6_B10X6R10X6_2PLANE_422_UNORM_3PACK16_KHR`

  - `VK_FORMAT_G10X6_B10X6_R10X6_3PLANE_444_UNORM_3PACK16_KHR`

  - `VK_FORMAT_R12X4_UNORM_PACK16_KHR`

  - `VK_FORMAT_R12X4G12X4_UNORM_2PACK16_KHR`

  - `VK_FORMAT_R12X4G12X4B12X4A12X4_UNORM_4PACK16_KHR`

  - `VK_FORMAT_G12X4B12X4G12X4R12X4_422_UNORM_4PACK16_KHR`

  - `VK_FORMAT_B12X4G12X4R12X4G12X4_422_UNORM_4PACK16_KHR`

  - `VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_420_UNORM_3PACK16_KHR`

  - `VK_FORMAT_G12X4_B12X4R12X4_2PLANE_420_UNORM_3PACK16_KHR`

  - `VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_422_UNORM_3PACK16_KHR`

  - `VK_FORMAT_G12X4_B12X4R12X4_2PLANE_422_UNORM_3PACK16_KHR`

  - `VK_FORMAT_G12X4_B12X4_R12X4_3PLANE_444_UNORM_3PACK16_KHR`

  - `VK_FORMAT_G16B16G16R16_422_UNORM_KHR`

  - `VK_FORMAT_B16G16R16G16_422_UNORM_KHR`

  - `VK_FORMAT_G16_B16_R16_3PLANE_420_UNORM_KHR`

  - `VK_FORMAT_G16_B16R16_2PLANE_420_UNORM_KHR`

  - `VK_FORMAT_G16_B16_R16_3PLANE_422_UNORM_KHR`

  - `VK_FORMAT_G16_B16R16_2PLANE_422_UNORM_KHR`

  - `VK_FORMAT_G16_B16_R16_3PLANE_444_UNORM_KHR`

- Extending VkImageAspectFlagBits:

  - `VK_IMAGE_ASPECT_PLANE_0_BIT_KHR`

  - `VK_IMAGE_ASPECT_PLANE_1_BIT_KHR`

  - `VK_IMAGE_ASPECT_PLANE_2_BIT_KHR`

- Extending VkImageCreateFlagBits:

  - `VK_IMAGE_CREATE_DISJOINT_BIT_KHR`

- Extending VkFormatFeatureFlagBits:

  - `VK_FORMAT_FEATURE_MIDPOINT_CHROMA_SAMPLES_BIT_KHR`

  - `VK_FORMAT_FEATURE_COSITED_CHROMA_SAMPLES_BIT_KHR`

  - `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_LINEAR_FILTER_BIT_KHR`

  - `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_SEPARATE_RECONSTRUCTION_FILTER_BIT_KHR`

  - `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_BIT_KHR`

  - `VK_FORMAT_FEATURE_SAMPLED_IMAGE_YCBCR_CONVERSION_CHROMA_RECONSTRUCTION_EXPLICIT_FORCEABLE_BIT_KHR`

  - `VK_FORMAT_FEATURE_DISJOINT_BIT_KHR`

#### New Enums

- VkSamplerYcbcrModelConversionKHR

- VkSamplerYcbcrRangeKHR

- VkChromaLocationKHR

#### New Structures

- VkSamplerYcbcrConversionInfoKHR

- VkSamplerYcbcrConversionCreateInfoKHR

- VkBindImagePlaneMemoryInfoKHR

- VkImagePlaneMemoryRequirementsInfoKHR

- VkPhysicalDeviceSamplerYcbcrConversionFeaturesKHR

- VkSamplerYcbcrConversionImageFormatPropertiesKHR

#### New Functions

- vkCreateSamplerYcbcrConversionKHR

- vkDestroySamplerYcbcrConversionKHR

#### New Objects

- VkSamplerYcbcrConversionKHR

#### Promotion to Vulkan 1.1

All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Version History

- Revision 1, 2017-01-24 (Andrew Garrard)

  - Initial draft

- Revision 2, 2017-01-25 (Andrew Garrard)

  - After initial feedback

- Revision 3, 2017-01-27 (Andrew Garrard)

  - Higher bit depth formats, renaming, swizzle

- Revision 4, 2017-02-22 (Andrew Garrard)

  - Added query function, formats as RGB, clarifications

- Revision 5, 2017-04 (Andrew Garrard)

  - Simplified query and removed output conversions

- Revision 6, 2017-4-24 (Andrew Garrard)

  - Tidying, incorporated new image query, restored transfer functions

- Revision 7, 2017-04-25 (Andrew Garrard)

  - Added cosited option/midpoint requirement for formats, "bypassConversion"

- Revision 8, 2017-04-25 (Andrew Garrard)

  - Simplified further

- Revision 9, 2017-04-27 (Andrew Garrard)

  - Disjoint no more

- Revision 10, 2017-04-28 (Andrew Garrard)

  - Restored disjoint

- Revision 11, 2017-04-29 (Andrew Garrard)

  - Now Ycbcr conversion, and KHR

- Revision 12, 2017-06-06 (Andrew Garrard)

  - Added conversion to image view creation

- Revision 13, 2017-07-13 (Andrew Garrard)

  - Allowed cosited-only chroma samples for formats

- Revision 14, 2017-08-11 (Andrew Garrard)

  - Reflected quantization changes in BT.2100-1

#### VK_KHR_separate_depth_stencil_layouts

Name String

  `VK_KHR_separate_depth_stencil_layouts`

Extension Type

  Device extension

Registered Extension Number

  242

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

  - Requires `VK_KHR_create_renderpass2`

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Piers Daniell pdaniell-nv

Last Modified Data

  2019-06-25

Interactions and External Dependencies

  - Promoted to Vulkan 1.2 Core

Contributors

  - Daniel Koch, NVIDIA

  - Jeff Bolz, NVIDIA

  - Jesse Barker, Unity

  - Tobias Hector, AMD

This extension allows image memory barriers for depth/stencil images to have just one of the `VK_IMAGE_ASPECT_DEPTH_BIT` or `VK_IMAGE_ASPECT_STENCIL_BIT` aspect bits set, rather than require both. This allows their layouts to be set independently. To support depth/stencil images with different layouts for the depth and stencil aspects, the depth/stencil attachment interface has been updated to support a separate layout for stencil.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SEPARATE_DEPTH_STENCIL_LAYOUTS_FEATURES_KHR`

  - `VK_STRUCTURE_TYPE_ATTACHMENT_REFERENCE_STENCIL_LAYOUT_KHR`

  - `VK_STRUCTURE_TYPE_ATTACHMENT_DESCRIPTION_STENCIL_LAYOUT_KHR`

- Extending VkImageLayout:

  - `VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL_KHR`

  - `VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL_KHR`

  - `VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL_KHR`

  - `VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL_KHR`

#### New Enums

None.

#### New Structures

- Extending VkPhysicalDeviceFeatures2:

  - VkPhysicalDeviceSeparateDepthStencilLayoutsFeaturesKHR

- Extending VkAttachmentReference2KHR:

  - VkAttachmentReferenceStencilLayoutKHR

- Extending VkAttachmentDescription2KHR:

  - VkAttachmentDescriptionStencilLayoutKHR

#### New Functions

None.

#### New SPIR-V Capabilities

None.

#### Promotion to Vulkan 1.2

All functionality in this extension is included in core Vulkan 1.2, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

None.

#### Version History

- Revision 1, 2019-06-25 (Piers Daniell)

  - Internal revisions

#### VK_KHR_shader_atomic_int64

Name String

  `VK_KHR_shader_atomic_int64`

Extension Type

  Device extension

Registered Extension Number

  181

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Aaron Hagan ahagan

Last Modified Date

  2018-07-05

Interactions and External Dependencies

  - Promoted to Vulkan 1.2 Core

Interactions and External Dependencies

  - This extension requires the `GL_ARB_gpu_shader_int64` and `GL_EXT_shader_atomic_int64` extensions for GLSL source languages.

Contributors

  - Aaron Hagan, AMD

  - Daniel Rakos, AMD

  - Jeff Bolz, NVIDIA

  - Neil Henning, Codeplay

This extension advertises the SPIR-V Int64Atomics capability for Vulkan, which allows a shader to contain 64-bit atomic operations on signed and unsigned integers. The supported operations include OpAtomicMin, OpAtomicMax, OpAtomicAnd, OpAtomicOr, OpAtomicXor, OpAtomicAdd, OpAtomicExchange, and OpAtomicCompareExchange.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_ATOMIC_INT64_FEATURES_KHR`

#### New SPIR-V Capabilities

- `Int64Atomics`

#### New Structures

- VkPhysicalDeviceShaderAtomicInt64FeaturesKHR

#### Promotion to Vulkan 1.2

All functionality in this extension is included in core Vulkan 1.2, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Version History

- Revision 1, 2018-07-05 (Aaron Hagan)

  - Internal revisions

#### VK_KHR_shader_draw_parameters

Name String

  `VK_KHR_shader_draw_parameters`

Extension Type

  Device extension

Registered Extension Number

  64

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Promoted to Vulkan 1.1

Contact

  - Daniel Koch dgkoch

Last Modified Date

  2017-09-05

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Requires the `SPV_KHR_shader_draw_parameters` SPIR-V extension.

  - Requires `GL_ARB_shader_draw_parameters` for GLSL source languages.

  - Promoted to Vulkan 1.1 Core

Contributors

  - Daniel Koch, NVIDIA Corporation

  - Jeff Bolz, NVIDIA

  - Daniel Rakos, AMD

  - Jan-Harald Fredriksen, ARM

  - John Kessenich, Google

  - Stuart Smith, IMG

This extension adds support for the following SPIR-V extension in Vulkan:

- `SPV_KHR_shader_draw_parameters`

The extension provides access to three additional built-in shader variables in Vulkan:

- `BaseInstance`, which contains the `firstInstance` parameter passed to draw commands,

- `BaseVertex`, which contains the `firstVertex` or `vertexOffset` parameter passed to draw commands, and

- `DrawIndex`, which contains the index of the draw call currently being processed from an indirect draw call.

When using GLSL source-based shader languages, the following variables from `GL_ARB_shader_draw_parameters` can map to these SPIR-V built-in decorations:

- `in int gl_BaseInstanceARB;` → `BaseInstance`,

- `in int gl_BaseVertexARB;` → `BaseVertex`, and

- `in int gl_DrawIDARB;` → `DrawIndex`.

#### New Object Types

None.

#### New Enum Constants

None.

#### New Enums

None.

#### New Structures

None.

#### New Functions

None.

#### New Built-In Variables

- `BaseInstance`

- `BaseVertex`

- `DrawIndex`

#### New SPIR-V Capabilities

- DrawParameters

#### Promotion to Vulkan 1.1

All functionality in this extension is included in core Vulkan 1.1, however a feature bit was added to distinguish whether it is actually available or not.

#### Issues

1) Is this the same functionality as `GL_ARB_shader_draw_parameters`?

RESOLVED: It’s actually a superset as it also adds in support for arrayed drawing commands.

In GL for `GL_ARB_shader_draw_parameters`, `gl_BaseVertexARB` holds the integer value passed to the parameter to the command that resulted in the current shader invocation. In the case where the command has no `baseVertex` parameter, the value of `gl_BaseVertexARB` is zero. This means that `gl_BaseVertexARB` = `baseVertex` (for `glDrawElements` commands with `baseVertex`) or 0. In particular there are no `glDrawArrays` commands that take a `baseVertex` parameter.

Now in Vulkan, we have `BaseVertex` = `vertexOffset` (for indexed drawing commands) or `firstVertex` (for arrayed drawing commands), and so Vulkan’s version is really a superset of GL functionality.

#### Version History

- Revision 1, 2016-10-05 (Daniel Koch)

  - Internal revisions

#### VK_KHR_shader_float16_int8

Name String

  `VK_KHR_shader_float16_int8`

Extension Type

  Device extension

Registered Extension Number

  83

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Alexander Galazin alegal-arm

Last Modified Date

  2018-03-07

Interactions and External Dependencies

  - Promoted to Vulkan 1.2 Core

IP Status

  No known IP claims.

Interactions and External Dependencies

  - This extension interacts with `VK_KHR_8bit_storage`

  - This extension interacts with `VK_KHR_16bit_storage`

  - This extension interacts with `VK_KHR_shader_float_controls`

Contributors

  - Alexander Galazin, Arm

  - Jan-Harald Fredriksen, Arm

  - Jeff Bolz, NVIDIA

  - Graeme Leese, Broadcom

  - Daniel Rakos, AMD

#### Description

The `VK_KHR_shader_float16_int8` extension allows use of 16-bit floating-point types and 8-bit integer types in shaders for arithmetic operations.

It introduces two new optional features `shaderFloat16` and `shaderInt8` which directly map to the `Float16` and the `Int8` SPIR-V capabilities. The `VK_KHR_shader_float16_int8` extension also specifies precision requirements for half-precision floating-point SPIR-V operations. This extension does not enable use of 8-bit integer types or 16-bit floating-point types in any shader input and output interfaces and therefore does not supersede the `VK_KHR_8bit_storage` or `VK_KHR_16bit_storage` extensions.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_FLOAT16_INT8_FEATURES_KHR`

#### New Structures

- VkPhysicalDeviceShaderFloat16Int8FeaturesKHR

#### New Functions

- None

#### Promotion to Vulkan 1.2

All functionality in this extension is included in core Vulkan 1.2, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Version History

- Revision 1, 2018-03-07 (Alexander Galazin)

  - Initial draft

#### VK_KHR_shader_float_controls

Name String

  `VK_KHR_shader_float_controls`

Extension Type

  Device extension

Registered Extension Number

  198

Revision

  4

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Alexander Galazin alegal-arm

Last Modified Date

  2018-09-11

Interactions and External Dependencies

  - Promoted to Vulkan 1.2 Core

IP Status

  No known IP claims.

Interactions and External Dependencies

  - This extension requires `SPV_KHR_float_controls`

Contributors

  - Alexander Galazin, Arm

  - Jan-Harald Fredriksen, Arm

  - Jeff Bolz, NVIDIA

  - Graeme Leese, Broadcom

  - Daniel Rakos, AMD

#### Description

The `VK_KHR_shader_float_controls` extension enables efficient use of floating-point computations through the ability to query and override the implementation’s default behavior for rounding modes, denormals, signed zero, and infinity.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_FLOAT_CONTROLS_PROPERTIES_KHR`

#### New Enums

- None

#### New Structures

- VkPhysicalDeviceFloatControlsPropertiesKHR

#### New Functions

- None

#### New SPIR-V Capabilities

- `DenormPreserve`

- `DenormFlushToZero`

- `SignedZeroInfNanPreserve`

- `RoundingModeRTE`

- `RoundingModeRTZ`

#### Promotion to Vulkan 1.2

All functionality in this extension is included in core Vulkan 1.2, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

1) Which instructions must flush denorms?

RESOLVED: Only floating-point conversion, floating-point arithmetic, floating-point relational (except `OpIsNaN`, `OpIsInf`), and floating-point GLSL.std.450 extended instructions must flush denormals.

2) What is the denorm behavior for intermediate results?

RESOLVED: When a SPIR-V instruction is implemented as a sequence of other instructions: - in the `DenormFlushToZero` execution mode the intermediate instructions may flush denormals, the final result of the sequence must not be denormal. - in the `DenormPreserve` execution mode denormals must be preserved throughout the whole sequence.

3) Do denorm and rounding mode controls apply to `OpSpecConstantOp`?

RESOLVED: Yes, except when the opcode is `OpQuantizeToF16`.

4) The SPIR-V specification says that `OpConvertFToU` and `OpConvertFToS` unconditionally round towards zero. Do the rounding mode controls specified through the execution modes apply to them?

RESOLVED: No, these instructions unconditionally round towards zero.

5) Do any of the "Pack" GLSL.std.450 instructions count as conversion instructions and have the rounding mode apply?

RESOLVED: No, only instructions listed in the section "3.32.11. Conversion Instructions" of the SPIR-V specification count as conversion instructions.

6) When using inf/nan-ignore mode, what is expected of `OpIsNan` and `OpIsInf`?

RESOLVED: These instructions must always accurately detect inf/nan if it is passed to them.

#### Version 4 API incompatibility

The original versions of `VK_KHR_shader_float_controls` shipped with booleans named “separateDenormSettings” and “separateRoundingModeSettings”, which at first glance could have indicated “they can all independently set, or not”. However the spec language as written indicated that the 32-bit value could always be set independently, and only the 16- and 64-bit controls needed to be the same if these values were `VK_FALSE`.

As a result of this slight disparity, and lack of test coverage for this facet of the extension, we ended up with two different behaviors in the wild, where some implementations worked as written, and others worked based on the naming. As these are hard limits in hardware with reasons for exposure as written, it was not possible to standardise on a single way to make this work within the existing API.

No known users of this part of the extension exist in the wild, and as such the Vulkan WG took the unusual step of retroactively changing the once boolean value into a tri-state enum, breaking source compatibility. This was however done in such a way as to retain ABI compatibility, in case any code using this did exist; with the numerical values 0 and 1 retaining their original specified meaning, and a new value signifying the additional “all need to be set together” state. If any applications exist today, compiled binaries will continue to work as written in most cases, but will need changes before the code can be recompiled.

#### Version History

- Revision 4, 2019-06-18 (Tobias Hector)

  - Modified settings restrictions, see Version 4 API incompatibility

- Revision 3, 2018-09-11 (Alexander Galazin)

  - Minor restructuring

- Revision 2, 2018-04-17 (Alexander Galazin)

  - Added issues and resolutions

- Revision 1, 2018-04-11 (Alexander Galazin)

  - Initial draft

#### VK_KHR_shader_subgroup_extended_types

Name String

  `VK_KHR_shader_subgroup_extended_types`

Extension Type

  Device extension

Registered Extension Number

  176

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.1

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Neil Henning sheredom

Last Modified Date

  2019-01-08

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Promoted to Vulkan 1.2 Core

Contributors

  - Jeff Bolz, NVIDIA

  - Jan-Harald Fredriksen, Arm

  - Neil Henning, AMD

  - Daniel Koch, NVIDIA

  - Jeff Leger, Qualcomm

  - Graeme Leese, Broadcom

  - David Neto, Google

  - Daniel Rakos, AMD

This extension enables the Non Uniform Group Operations in SPIR-V to support 8-bit integer, 16-bit integer, 64-bit integer, 16-bit floating-point, and vectors of these types.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_SUBGROUP_EXTENDED_TYPES_FEATURES_KHR`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceShaderSubgroupExtendedTypesFeaturesKHR

#### New Functions

None.

#### New Built-In Variables

None.

#### New SPIR-V Capabilities

None.

#### Promotion to Vulkan 1.2

All functionality in this extension is included in core Vulkan 1.2, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

None.

#### Version History

- Revision 1, 2019-01-08 (Neil Henning)

  - Initial draft

#### VK_KHR_spirv_1_4

Name String

  `VK_KHR_spirv_1_4`

Extension Type

  Device extension

Registered Extension Number

  237

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.1

  - Requires `VK_KHR_shader_float_controls`

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Jesse Hall critsec

Last Modified Date

  2019-04-01

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Requires SPIR-V 1.4.

  - Promoted to Vulkan 1.2 Core

Contributors

  - Alexander Galazin, Arm

  - David Neto, Google

  - Jesse Hall, Google

  - John Kessenich, Google

  - Neil Henning, AMD

  - Tom Olson, Arm

This extension allows the use of SPIR-V 1.4 shader modules. SPIR-V 1.4’s new features primarily make it an easier target for compilers from high-level languages, rather than exposing new hardware functionality.

SPIR-V 1.4 incorporates features that are also available separately as extensions. SPIR-V 1.4 shader modules do not need to enable those extensions with the `OpExtension` opcode, since they are integral parts of SPIR-V 1.4.

SPIR-V 1.4 introduces new floating point execution mode capabilities, also available via `SPV_KHR_float_controls`. Implementations are not required to support all of these new capabilities; support can be queried using VkPhysicalDeviceFloatControlsPropertiesKHR from the `VK_KHR_shader_float_controls` extension.

#### New Object Types

None.

#### New Enum Constants

None.

#### New Enums

None.

#### New Structures

None.

#### New Functions

None.

#### Promotion to Vulkan 1.2

All functionality in this extension is included in core Vulkan 1.2, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

1. Should we have an extension specific to this SPIR-V version, or add a version-generic query for SPIR-V version? SPIR-V 1.4 doesn’t need any other API changes.

RESOLVED: Just expose SPIR-V 1.4.

Most new SPIR-V versions introduce optionally-required capabilities or have implementation-defined limits, and would need more API and specification changes specific to that version to make them available in Vulkan. For example, to support the subgroup capabilities added in SPIR-V 1.3 required introducing VkPhysicalDeviceSubgroupProperties to allow querying the supported group operation categories, maximum supported subgroup size, etc. While we could expose the parts of a new SPIR-V version that don’t need accompanying changes generically, we’ll still end up writing extensions specific to each version for the remaining parts. Thus the generic mechanism won’t reduce future spec-writing effort. In addition, making it clear which parts of a future version are supported by the generic mechanism and which can’t be used without specific support would be difficult to get right ahead of time.

2. Can different stages of the same pipeline use shaders with different SPIR-V versions?

RESOLVED: Yes.

Mixing SPIR-V versions 1.0-1.3 in the same pipeline has not been disallowed, so it would be inconsistent to disallow mixing 1.4 with previous versions.. SPIR-V 1.4 does not introduce anything that should cause new difficulties here.

3. Must Vulkan extensions corresponding to SPIR-V extensions that were promoted to core in 1.4 be enabled in order to use that functionality in a SPIR-V 1.4 module?

RESOLVED: No, with caveats.

The SPIR-V 1.4 module does not need to declare the SPIR-V extensions, since the functionality is now part of core, so there is no need to enable the Vulkan extension that allows SPIR-V modules to declare the SPIR-V extension. However, when the functionality that is now core in SPIR-V 1.4 is optionally supported, the query for support is provided by a Vulkan extension, and that query can only be used if the extension is enabled.

This applies to any SPIR-V version; specifically for SPIR-V 1.4 this only applies to the functionality from `SPV_KHR_float_controls`, which was made available in Vulkan by `VK_KHR_shader_float_controls`. Even though the extension was promoted in SPIR-V 1.4, the capabilities are still optional in implementations that support `VK_KHR_spirv_1_4`.

A SPIR-V 1.4 module doesn’t need to enable `SPV_KHR_float_controls` in order to use the capabilities, so if the application has a priori knowledge that the implementation supports the capabilities, it doesn’t need to enable `VK_KHR_shader_float_controls`. However, if it doesn’t have this knowledge and has to query for support at runtime, it must enable `VK_KHR_shader_float_controls` in order to use VkPhysicalDeviceFloatControlsPropertiesKHR.

#### Version History

- Revision 1, 2019-04-01 (Jesse Hall)

  - Internal draft versions

#### VK_KHR_storage_buffer_storage_class

Name String

  `VK_KHR_storage_buffer_storage_class`

Extension Type

  Device extension

Registered Extension Number

  132

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Promoted to Vulkan 1.1

Contact

  - Alexander Galazin alegal-arm

Last Modified Date

  2017-09-05

IP Status

  No known IP claims.

Interactions and External Dependencies

  - This extension requires the `SPV_KHR_storage_buffer_storage_class` SPIR-V extension.

  - Promoted to Vulkan 1.1 Core

Contributors

  - Alexander Galazin, ARM

  - David Neto, Google

This extension adds support for the following SPIR-V extension in Vulkan:

- `SPV_KHR_storage_buffer_storage_class`

This extension provides a new SPIR-V `StorageBuffer` storage class. A `Block`-decorated object in this class is equivalent to a `BufferBlock`-decorated object in the `Uniform` storage class.

#### New Enum Constants

None.

#### New Structures

None.

#### Promotion to Vulkan 1.1

All functionality in this extension is included in core Vulkan 1.1.

#### Issues

None.

#### Version History

- Revision 1, 2017-03-23 (Alexander Galazin)

  - Initial draft

#### VK_KHR_timeline_semaphore

Name String

  `VK_KHR_timeline_semaphore`

Extension Type

  Device extension

Registered Extension Number

  208

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Jason Ekstrand jekstrand

Last Modified Date

  2019-06-12

IP Status

  No known IP claims.

Interactions and External Dependencies

  - This extension interacts with `VK_KHR_external_semaphore_capabilities`

  - This extension interacts with `VK_KHR_external_semaphore`

  - This extension interacts with `VK_KHR_external_semaphore_win32`

  - Promoted to Vulkan 1.2 Core

Contributors

  - Jeff Bolz, NVIDIA

  - Yuriy O’Donnell, Epic Games

  - Jason Ekstrand, Intel

  - Jesse Hall, Google

  - James Jones, NVIDIA

  - Jeff Juliano, NVIDIA

  - Daniel Rakos, AMD

  - Ray Smith, Arm

This extension introduces a new type of semaphore that has an integer payload identifying a point in a timeline. Such timeline semaphores support the following operations:

- Host query - A host operation that allows querying the payload of the timeline semaphore.

- Host wait - A host operation that allows a blocking wait for a timeline semaphore to reach a specified value.

- Host signal - A host operation that allows advancing the timeline semaphore to a specified value.

- Device wait - A device operation that allows waiting for a timeline semaphore to reach a specified value.

- Device signal - A device operation that allows advancing the timeline semaphore to a specified value.

#### New Object Types

None

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TIMELINE_SEMAPHORE_FEATURES_KHR`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_TIMELINE_SEMAPHORE_PROPERTIES_KHR`

  - `VK_STRUCTURE_TYPE_SEMAPHORE_TYPE_CREATE_INFO_KHR`

  - `VK_STRUCTURE_TYPE_TIMELINE_SEMAPHORE_SUBMIT_INFO_KHR`

  - `VK_STRUCTURE_TYPE_SEMAPHORE_WAIT_INFO_KHR`

  - `VK_STRUCTURE_TYPE_SEMAPHORE_SIGNAL_INFO_KHR`

#### New Enums

- VkSemaphoreTypeKHR

#### New Structs

- VkPhysicalDeviceTimelineSemaphoreFeaturesKHR

- VkPhysicalDeviceTimelineSemaphorePropertiesKHR

- VkSemaphoreTypeCreateInfoKHR

- VkTimelineSemaphoreSubmitInfoKHR

- VkSemaphoreWaitInfoKHR

- VkSemaphoreSignalInfoKHR

#### New Functions

- vkGetSemaphoreCounterValueKHR

- vkWaitSemaphoresKHR

- vkSignalSemaphoreKHR

#### Promotion to Vulkan 1.2

All functionality in this extension is included in core Vulkan 1.2, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

1) Do we need a new object type for this?

RESOLVED: No, we just introduce a new type of semaphore object, as `VK_KHR_external_semaphore_win32` already uses semaphores as the destination for importing D3D12 fence objects, which are semantically close/identical to the proposed synchronization primitive.

2) What type of payload the new synchronization primitive has?

RESOLVED: A 64-bit unsigned integer that can only be set to monotonically increasing values by signal operations and is not changed by wait operations.

3) Does the new synchronization primitive have the same signal-before-wait requirement as the existing semaphores do?

RESOLVED: No. Timeline semaphores support signaling and waiting entirely asynchronously. It is the responsibility of the client to avoid deadlock.

4) Does the new synchronization primitive allow resetting its payload?

RESOLVED: No, allowing the payload value to "go backwards" is problematic. Applications looking for reset behavior should create a new instance of the sychronization primitive instead.

5) How do we enable host waits on the synchronization primitive?

RESOLVED: Both a non-blocking query of the current payload value of the synchronization primitive, and a blocking wait operation are provided.

6) How do we enable device waits and signals on the synchronization primitive?

RESOLVED: Similar to `VK_KHR_external_semaphore_win32`, this extension introduces a new structure that can be chained to VkSubmitInfo to specify the values signaled semaphores should be set to, and the values waited semaphores need to reach.

7) Can the new synchronization primitive be used to synchronize presentation and swapchain image acquisition operations?

RESOLVED: Some implementations may have problems with supporting that directly, thus it’s not allowed in this extension.

8) Do we want to support external sharing of the new synchronization primitive type?

RESOLVED: Yes. Timeline semaphore specific external sharing capabilities can be queried using vkGetPhysicalDeviceExternalSemaphoreProperties by chaining the new VkSemaphoreTypeCreateInfoKHR structure to its `pExternalSemaphoreInfo` structure. This allows having a different set of external semaphore handle types supported for timeline semaphores vs binary semaphores.

9) Do we need to add a host signal operation for the new synchronization primitive type?

RESOLVED: Yes. This helps in situations where one host thread submits a workload but another host thread has the information on when the workload is ready to be executed.

10) How should the new synchronization primitive interact with the ordering requirements of the original `VkSemaphore`?

RESOLVED: Prior to calling any command which may cause a wait operation on a binary semaphore, the client must ensure that the semaphore signal operation that has been submitted for execution and any semaphore signal operations on which it depends (if any) must have also been submitted for execution.

11) Should we have separate feature bits for different sub-features of timeline semaphores?

RESOLVED: No. The only feature which cannot be supported universally is timeline semaphore import/export. For import/export, the client is already required to query available external handle types via vkGetPhysicalDeviceExternalSemaphoreProperties and provide the semaphore type by adding a VkSemaphoreTypeCreateInfoKHR structure to the `pNext` chain of VkPhysicalDeviceExternalSemaphoreInfo so no new feature bit is required.

#### Version History

- Revision 1, 2018-05-10 (Jason Ekstrand)

  - Initial version

- Revision 2, 2019-06-12 (Jason Ekstrand)

  - Added an initialValue parameter to timeline semaphore creation

#### VK_KHR_uniform_buffer_standard_layout

Name String

  `VK_KHR_uniform_buffer_standard_layout`

Extension Type

  Device extension

Registered Extension Number

  254

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Graeme Leese gnl21

Last Modified Date

  2019-01-25

Interactions and External Dependencies

  - Promoted to Vulkan 1.2 Core

Contributors

  - Graeme Leese, Broadcom

  - Jeff Bolz, NVIDIA

  - Tobias Hector, AMD

  - Jason Ekstrand, Intel

  - Neil Henning, AMD

#### Short Description

Enables tighter array and struct packing to be used with uniform buffers.

#### Description

This extension modifies the alignment rules for uniform buffers, allowing for tighter packing of arrays and structures. This allows, for example, the std430 layout, as defined in GLSL to be supported in uniform buffers.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_UNIFORM_BUFFER_STANDARD_LAYOUT_FEATURES_KHR`

#### New Structures

- VkPhysicalDeviceUniformBufferStandardLayoutFeaturesKHR

#### Issues

None.

#### Promotion to Vulkan 1.2

All functionality in this extension is included in core Vulkan 1.2, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Version History

- Revision 1, 2019-01-25 (Graeme Leese)

  - Initial draft

#### VK_KHR_variable_pointers

Name String

  `VK_KHR_variable_pointers`

Extension Type

  Device extension

Registered Extension Number

  121

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

  - Requires `VK_KHR_storage_buffer_storage_class`

Deprecation state

  - Promoted to Vulkan 1.1

Contact

  - Jesse Hall critsec

Last Modified Date

  2017-09-05

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Requires the `SPV_KHR_variable_pointers` SPIR-V extension.

  - Promoted to Vulkan 1.1 Core

Contributors

  - John Kessenich, Google

  - Neil Henning, Codeplay

  - David Neto, Google

  - Daniel Koch, Nvidia

  - Graeme Leese, Broadcom

  - Weifeng Zhang, Qualcomm

  - Stephen Clarke, Imagination Technologies

  - Jason Ekstrand, Intel

  - Jesse Hall, Google

The `VK_KHR_variable_pointers` extension allows implementations to indicate their level of support for the `SPV_KHR_variable_pointers` SPIR-V extension. The SPIR-V extension allows shader modules to use invocation-private pointers into uniform and/or storage buffers, where the pointer values can be dynamic and non-uniform.

The `SPV_KHR_variable_pointers` extension introduces two capabilities. The first, `VariablePointersStorageBuffer`, must be supported by all implementations of this extension. The second, `VariablePointers`, is optional.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VARIABLE_POINTER_FEATURES_KHR`

#### New Structures

- VkPhysicalDeviceVariablePointersFeaturesKHR

#### New SPIR-V Capabilities

- VariablePointersStorageBuffer

- VariablePointers

#### Promotion to Vulkan 1.1

All functionality in this extension is included in core Vulkan 1.1, with the KHR suffix omitted, however support for the `variablePointersStorageBuffer` feature is made optional. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

1) Do we need an optional property for the SPIR-V `VariablePointersStorageBuffer` capability or should it be mandatory when this extension is advertised?

RESOLVED: Add it as a distinct feature, but make support mandatory. Adding it as a feature makes the extension easier to include in a future core API version. In the extension, the feature is mandatory, so that presence of the extension guarantees some functionality. When included in a core API version, the feature would be optional.

2) Can support for these capabilities vary between shader stages?

RESOLVED: No, if the capability is supported in any stage it must be supported in all stages.

3) Should the capabilities be features or limits?

RESOLVED: Features, primarily for consistency with other similar extensions.

#### Version History

- Revision 1, 2017-03-14 (Jesse Hall and John Kessenich)

  - Internal revisions

#### VK_KHR_vulkan_memory_model

Name String

  `VK_KHR_vulkan_memory_model`

Extension Type

  Device extension

Registered Extension Number

  212

Revision

  3

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Jeff Bolz jeffbolznv

Last Modified Date

  2018-12-10

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Promoted to Vulkan 1.2 Core

  - This extension requires `SPV_KHR_vulkan_memory_model`

Contributors

  - Jeff Bolz, NVIDIA

  - Alan Baker, Google

  - Tobias Hector, AMD

  - David Neto, Google

  - Robert Simpson, Qualcomm Technologies, Inc.

  - Brian Sumner, AMD

The `VK_KHR_vulkan_memory_model` extension allows use of the Vulkan Memory Model, which formally defines how to synchronize memory accesses to the same memory locations performed by multiple shader invocations.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_VULKAN_MEMORY_MODEL_FEATURES_KHR`

#### New Structures

- VkPhysicalDeviceVulkanMemoryModelFeaturesKHR

| Note Version 3 of the spec added a member (`vulkanMemoryModelAvailabilityVisibilityChains`) to VkPhysicalDeviceVulkanMemoryModelFeaturesKHR, which is an incompatible change from version 2.

#### New SPIR-V Capabilities

- `VulkanMemoryModelKHR`

#### Promotion to Vulkan 1.2

All functionality in this extension is included in core Vulkan 1.2, with the KHR suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

#### Version History

- Revision 1, 2018-06-24 (Jeff Bolz)

  - Initial draft

- Revision 3, 2018-12-10 (Jeff Bolz)

  - Add vulkanMemoryModelAvailabilityVisibilityChains member to the VkPhysicalDeviceVulkanMemoryModelFeaturesKHR structure.

#### VK_EXT_buffer_device_address

Name String

  `VK_EXT_buffer_device_address`

Extension Type

  Device extension

Registered Extension Number

  245

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Deprecation state

  - Deprecated by `VK_KHR_buffer_device_address` extension

    - Which in turn was promoted to Vulkan 1.2

Contact

  - Jeff Bolz jeffbolznv

Last Modified Date

  2019-01-06

IP Status

  No known IP claims.

Contributors

  - Jeff Bolz, NVIDIA

  - Neil Henning, AMD

  - Tobias Hector, AMD

  - Jason Ekstrand, Intel

  - Baldur Karlsson, Valve

This extension allows the application to query a 64-bit buffer device address value for a buffer, which can be used to access the buffer memory via the `PhysicalStorageBufferEXT` storage class in the `GL_EXT_buffer_reference` GLSL extension and `SPV_EXT_physical_storage_buffer` SPIR-V extension.

It also allows buffer device addresses to be provided by a trace replay tool, so that it matches the address used when the trace was captured.

#### New Object Types

None

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_BUFFER_DEVICE_ADDRESS_FEATURES_EXT`

  - `VK_STRUCTURE_TYPE_BUFFER_DEVICE_ADDRESS_INFO_EXT`

  - `VK_STRUCTURE_TYPE_BUFFER_DEVICE_ADDRESS_CREATE_INFO_EXT`

- Extending VkBufferUsageFlagBits:

  - `VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT_EXT`

- Extending VkBufferCreateFlagBits:

  - `VK_BUFFER_CREATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT_EXT`

- Extending VkResult:

  - `VK_ERROR_INVALID_DEVICE_ADDRESS_EXT`

#### New Enums

None

#### New Structures

- VkPhysicalDeviceBufferDeviceAddressFeaturesEXT

- VkBufferDeviceAddressInfoEXT

- VkBufferDeviceAddressCreateInfoEXT

#### New Functions

- vkGetBufferDeviceAddressEXT

#### New Built-In Variables

None

#### New SPIR-V Capabilities

- `PhysicalStorageBufferAddressesEXT`

#### Issues

1) Where is VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_BUFFER_ADDRESS_FEATURES_EXT and VkPhysicalDeviceBufferAddressFeaturesEXT?

RESOLVED: They were renamed as `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_BUFFER_DEVICE_ADDRESS_FEATURES_EXT` and VkPhysicalDeviceBufferDeviceAddressFeaturesEXT accordingly for consistency. Even though, the old names can still be found in the generated header files for compatibility.

#### Version History

- Revision 1, 2018-11-01 (Jeff Bolz)

  - Internal revisions

- Revision 2, 2019-01-06 (Jon Leech)

  - Minor updates to appendix for publication

#### VK_EXT_debug_marker

Name String

  `VK_EXT_debug_marker`

Extension Type

  Device extension

Registered Extension Number

  23

Revision

  4

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_EXT_debug_report`

Deprecation state

  - Promoted to `VK_EXT_debug_utils` extension

Contact

  - Baldur Karlsson baldurk

Last Modified Date

  2017-01-31

IP Status

  No known IP claims.

Contributors

  - Baldur Karlsson

  - Dan Ginsburg, Valve

  - Jon Ashburn, LunarG

  - Kyle Spagnoli, NVIDIA

The `VK_EXT_debug_marker` extension is a device extension. It introduces concepts of object naming and tagging, for better tracking of Vulkan objects, as well as additional commands for recording annotations of named sections of a workload to aid organization and offline analysis in external tools.

#### New Object Types

None

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_DEBUG_MARKER_OBJECT_NAME_INFO_EXT`

  - `VK_STRUCTURE_TYPE_DEBUG_MARKER_OBJECT_TAG_INFO_EXT`

  - `VK_STRUCTURE_TYPE_DEBUG_MARKER_MARKER_INFO_EXT`

#### New Enums

None

#### New Structures

- VkDebugMarkerObjectNameInfoEXT

- VkDebugMarkerObjectTagInfoEXT

- VkDebugMarkerMarkerInfoEXT

#### New Functions

- vkDebugMarkerSetObjectTagEXT

- vkDebugMarkerSetObjectNameEXT

- vkCmdDebugMarkerBeginEXT

- vkCmdDebugMarkerEndEXT

- vkCmdDebugMarkerInsertEXT

#### Examples

Example 1

Associate a name with an image, for easier debugging in external tools or with validation layers that can print a friendly name when referring to objects in error messages.

        extern VkDevice device;
        extern VkImage image;

        // Must call extension functions through a function pointer:
        PFN_vkDebugMarkerSetObjectNameEXT pfnDebugMarkerSetObjectNameEXT = (PFN_vkDebugMarkerSetObjectNameEXT)vkGetDeviceProcAddr(device, "vkDebugMarkerSetObjectNameEXT");

        // Set a name on the image
        const VkDebugMarkerObjectNameInfoEXT imageNameInfo =
        {
            VK_STRUCTURE_TYPE_DEBUG_MARKER_OBJECT_NAME_INFO_EXT, // sType
            NULL,                                           // pNext
            VK_DEBUG_REPORT_OBJECT_TYPE_IMAGE_EXT,          // objectType
            (uint64_t)image,                                // object
            "Brick Diffuse Texture",                        // pObjectName
        };

        pfnDebugMarkerSetObjectNameEXT(device, &imageNameInfo);

        // A subsequent error might print:
        //   Image 'Brick Diffuse Texture' (0xc0dec0dedeadbeef) is used in a
        //   command buffer with no memory bound to it.

Example 2

Annotating regions of a workload with naming information so that offline analysis tools can display a more usable visualisation of the commands submitted.

        extern VkDevice device;
        extern VkCommandBuffer commandBuffer;

        // Must call extension functions through a function pointer:
        PFN_vkCmdDebugMarkerBeginEXT pfnCmdDebugMarkerBeginEXT = (PFN_vkCmdDebugMarkerBeginEXT)vkGetDeviceProcAddr(device, "vkCmdDebugMarkerBeginEXT");
        PFN_vkCmdDebugMarkerEndEXT pfnCmdDebugMarkerEndEXT = (PFN_vkCmdDebugMarkerEndEXT)vkGetDeviceProcAddr(device, "vkCmdDebugMarkerEndEXT");
        PFN_vkCmdDebugMarkerInsertEXT pfnCmdDebugMarkerInsertEXT = (PFN_vkCmdDebugMarkerInsertEXT)vkGetDeviceProcAddr(device, "vkCmdDebugMarkerInsertEXT");

        // Describe the area being rendered
        const VkDebugMarkerMarkerInfoEXT houseMarker =
        {
            VK_STRUCTURE_TYPE_DEBUG_MARKER_MARKER_INFO_EXT, // sType
            NULL,                                           // pNext
            "Brick House",                                  // pMarkerName
            { 1.0f, 0.0f, 0.0f, 1.0f },                     // color
        };

        // Start an annotated group of calls under the 'Brick House' name
        pfnCmdDebugMarkerBeginEXT(commandBuffer, &houseMarker);
        {
            // A mutable structure for each part being rendered
            VkDebugMarkerMarkerInfoEXT housePartMarker =
            {
                VK_STRUCTURE_TYPE_DEBUG_MARKER_MARKER_INFO_EXT, // sType
                NULL,                                           // pNext
                NULL,                                           // pMarkerName
                { 0.0f, 0.0f, 0.0f, 0.0f },                     // color
            };

            // Set the name and insert the marker
            housePartMarker.pMarkerName = "Walls";
            pfnCmdDebugMarkerInsertEXT(commandBuffer, &housePartMarker);

            // Insert the drawcall for the walls
            vkCmdDrawIndexed(commandBuffer, 1000, 1, 0, 0, 0);

            // Insert a recursive region for two sets of windows
            housePartMarker.pMarkerName = "Windows";
            pfnCmdDebugMarkerBeginEXT(commandBuffer, &housePartMarker);
            {
                vkCmdDrawIndexed(commandBuffer, 75, 6, 1000, 0, 0);
                vkCmdDrawIndexed(commandBuffer, 100, 2, 1450, 0, 0);
            }
            pfnCmdDebugMarkerEndEXT(commandBuffer);

            housePartMarker.pMarkerName = "Front Door";
            pfnCmdDebugMarkerInsertEXT(commandBuffer, &housePartMarker);

            vkCmdDrawIndexed(commandBuffer, 350, 1, 1650, 0, 0);

            housePartMarker.pMarkerName = "Roof";
            pfnCmdDebugMarkerInsertEXT(commandBuffer, &housePartMarker);

            vkCmdDrawIndexed(commandBuffer, 500, 1, 2000, 0, 0);
        }
        // End the house annotation started above
        pfnCmdDebugMarkerEndEXT(commandBuffer);

#### Issues

1) Should the tag or name for an object be specified using the `pNext` parameter in the object’s `Vk*CreateInfo` structure?

RESOLVED: No. While this fits with other Vulkan patterns and would allow more type safety and future proofing against future objects, it has notable downsides. In particular passing the name at `Vk*CreateInfo` time does not allow renaming, prevents late binding of naming information, and does not allow naming of implicitly created objects such as queues and swapchain images.

2) Should the command annotation functions vkCmdDebugMarkerBeginEXT and vkCmdDebugMarkerEndEXT support the ability to specify a color?

RESOLVED: Yes. The functions have been expanded to take an optional color which can be used at will by implementations consuming the command buffer annotations in their visualisation.

3) Should the functions added in this extension accept an extensible structure as their parameter for a more flexible API, as opposed to direct function parameters? If so, which functions?

RESOLVED: Yes. All functions have been modified to take a structure type with extensible `pNext` pointer, to allow future extensions to add additional annotation information in the same commands.

#### Version History

- Revision 1, 2016-02-24 (Baldur Karlsson)

  - Initial draft, based on LunarG marker spec

- Revision 2, 2016-02-26 (Baldur Karlsson)

  - Renamed Dbg to DebugMarker in function names

  - Allow markers in secondary command buffers under certain circumstances

  - Minor language tweaks and edits

- Revision 3, 2016-04-23 (Baldur Karlsson)

  - Reorganise spec layout to closer match desired organisation

  - Added optional color to markers (both regions and inserted labels)

  - Changed functions to take extensible structs instead of direct function parameters

- Revision 4, 2017-01-31 (Baldur Karlsson)

  - Added explicit dependency on VK_EXT_debug_report

  - Moved definition of VkDebugReportObjectTypeEXT to debug report chapter.

  - Fixed typo in dates in revision history

#### VK_EXT_debug_report

Name String

  `VK_EXT_debug_report`

Extension Type

  Instance extension

Registered Extension Number

  12

Revision

  9

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Deprecated by `VK_EXT_debug_utils` extension

Contact

  - Courtney Goeltzenleuchter courtney-g

Last Modified Date

  2017-09-12

IP Status

  No known IP claims.

Contributors

  - Courtney Goeltzenleuchter, LunarG

  - Dan Ginsburg, Valve

  - Jon Ashburn, LunarG

  - Mark Lobodzinski, LunarG

Due to the nature of the Vulkan interface, there is very little error information available to the developer and application. By enabling optional validation layers and using the `VK_EXT_debug_report` extension, developers can obtain much more detailed feedback on the application’s use of Vulkan. This extension defines a way for layers and the implementation to call back to the application for events of interest to the application.

#### New Object Types

- VkDebugReportCallbackEXT

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_DEBUG_REPORT_CALLBACK_CREATE_INFO_EXT`

- Extending VkResult:

  - `VK_ERROR_VALIDATION_FAILED_EXT`

#### New Enums

- VkDebugReportFlagBitsEXT

- VkDebugReportObjectTypeEXT

#### New Structures

- VkDebugReportCallbackCreateInfoEXT

#### New Functions

- vkCreateDebugReportCallbackEXT

- vkDestroyDebugReportCallbackEXT

- vkDebugReportMessageEXT

#### New Function Pointers

- PFN_vkDebugReportCallbackEXT

#### Examples

`VK_EXT_debug_report` allows an application to register multiple callbacks with the validation layers. Some callbacks may log the information to a file, others may cause a debug break point or other application defined behavior. An application can register callbacks even when no validation layers are enabled, but they will only be called for loader and, if implemented, driver events.

To capture events that occur while creating or destroying an instance an application can link a VkDebugReportCallbackCreateInfoEXT structure to the `pNext` element of the VkInstanceCreateInfo structure given to vkCreateInstance. This callback is only valid for the duration of the vkCreateInstance and the vkDestroyInstance call. Use vkCreateDebugReportCallbackEXT to create persistent callback objects.

Example uses: Create three callback objects. One will log errors and warnings to the debug console using Windows `OutputDebugString`. The second will cause the debugger to break at that callback when an error happens and the third will log warnings to stdout.

        VkResult res;
        VkDebugReportCallbackEXT cb1, cb2, cb3;

        VkDebugReportCallbackCreateInfoEXT callback1 = {
                VK_STRUCTURE_TYPE_DEBUG_REPORT_CALLBACK_CREATE_INFO_EXT,    // sType
                NULL,                                                       // pNext
                VK_DEBUG_REPORT_ERROR_BIT_EXT |                             // flags
                VK_DEBUG_REPORT_WARNING_BIT_EXT,
                myOutputDebugString,                                        // pfnCallback
                NULL                                                        // pUserData
        };
        res = vkCreateDebugReportCallbackEXT(instance, &callback1, &cb1);
        if (res != VK_SUCCESS)
           /* Do error handling for VK_ERROR_OUT_OF_MEMORY */

        callback.flags = VK_DEBUG_REPORT_ERROR_BIT_EXT;
        callback.pfnCallback = myDebugBreak;
        callback.pUserData = NULL;
        res = vkCreateDebugReportCallbackEXT(instance, &callback, &cb2);
        if (res != VK_SUCCESS)
           /* Do error handling for VK_ERROR_OUT_OF_MEMORY */

        VkDebugReportCallbackCreateInfoEXT callback3 = {
                VK_STRUCTURE_TYPE_DEBUG_REPORT_CALLBACK_CREATE_INFO_EXT,    // sType
                NULL,                                                       // pNext
                VK_DEBUG_REPORT_WARNING_BIT_EXT,                            // flags
                mystdOutLogger,                                             // pfnCallback
                NULL                                                        // pUserData
        };
        res = vkCreateDebugReportCallbackEXT(instance, &callback3, &cb3);
        if (res != VK_SUCCESS)
           /* Do error handling for VK_ERROR_OUT_OF_MEMORY */

        ...

        /* remove callbacks when cleaning up */
        vkDestroyDebugReportCallbackEXT(instance, cb1);
        vkDestroyDebugReportCallbackEXT(instance, cb2);
        vkDestroyDebugReportCallbackEXT(instance, cb3);

| Note In the initial release of the `VK_EXT_debug_report` extension, the token `VK_STRUCTURE_TYPE_DEBUG_REPORT_CREATE_INFO_EXT` was used. Starting in version 2 of the extension branch, `VK_STRUCTURE_TYPE_DEBUG_REPORT_CALLBACK_CREATE_INFO_EXT` is used instead for consistency with Vulkan naming rules. The older enum is still available for backwards compatibility.

| Note In the initial release of the `VK_EXT_debug_report` extension, the token `VK_DEBUG_REPORT_OBJECT_TYPE_DEBUG_REPORT_EXT` was used. Starting in version 8 of the extension branch, `VK_DEBUG_REPORT_OBJECT_TYPE_DEBUG_REPORT_CALLBACK_EXT_EXT` is used instead for consistency with Vulkan naming rules. The older enum is still available for backwards compatibility.

#### Issues

1) What is the hierarchy / seriousness of the message flags? E.g. `ERROR` > `WARN` > `PERF_WARN` …​

RESOLVED: There is no specific hierarchy. Each bit is independent and should be checked via bitwise AND. For example:

        if (localFlags & VK_DEBUG_REPORT_ERROR_BIT_EXT) {
            process error message
        }
        if (localFlags & VK_DEBUG_REPORT_DEBUG_BIT_EXT) {
            process debug message
        }

The validation layers do use them in a hierarchical way (`ERROR` > `WARN` > `PERF`, `WARN` > `DEBUG` > `INFO`) and they (at least at the time of this writing) only set one bit at a time. But it is not a requirement of this extension.

It is possible that a layer may intercept and change, or augment the flags with extension values the application’s debug report handler may not be familiar with, so it is important to treat each flag independently.

2) Should there be a VU requiring VkDebugReportCallbackCreateInfoEXT::`flags` to be non-zero?

RESOLVED: It may not be very useful, but we do not need VU statement requiring the `VkDebugReportCallbackCreateInfoEXT`::`msgFlags` at create-time to be non-zero. One can imagine that apps may prefer it as it allows them to set the mask as desired - including nothing - at runtime without having to check.

3) What is the difference between `VK_DEBUG_REPORT_DEBUG_BIT_EXT` and `VK_DEBUG_REPORT_INFORMATION_BIT_EXT`?

RESOLVED: `VK_DEBUG_REPORT_DEBUG_BIT_EXT` specifies information that could be useful debugging the Vulkan implementation itself.

#### Version History

- Revision 1, 2015-05-20 (Courtney Goetzenleuchter)

  - Initial draft, based on LunarG KHR spec, other KHR specs

- Revision 2, 2016-02-16 (Courtney Goetzenleuchter)

  - Update usage, documentation

- Revision 3, 2016-06-14 (Courtney Goetzenleuchter)

  - Update VK_EXT_DEBUG_REPORT_SPEC_VERSION to indicate added support for vkCreateInstance and vkDestroyInstance

- Revision 4, 2016-12-08 (Mark Lobodzinski)

  - Added Display_KHR, DisplayModeKHR extension objects

  - Added ObjectTable_NVX, IndirectCommandsLayout_NVX extension objects

  - Bumped spec revision

  - Retroactively added version history

- Revision 5, 2017-01-31 (Baldur Karlsson)

  - Moved definition of VkDebugReportObjectTypeEXT from debug marker chapter

- Revision 6, 2017-01-31 (Baldur Karlsson)

  - Added VK_DEBUG_REPORT_OBJECT_TYPE_DESCRIPTOR_UPDATE_TEMPLATE_KHR_EXT

- Revision 7, 2017-04-20 (Courtney Goeltzenleuchter)

  - Clarify wording and address questions from developers.

- Revision 8, 2017-04-21 (Courtney Goeltzenleuchter)

  - Remove unused enum VkDebugReportErrorEXT

- Revision 9, 2017-09-12 (Tobias Hector)

  - Added interactions with Vulkan 1.1

#### VK_EXT_descriptor_indexing

Name String

  `VK_EXT_descriptor_indexing`

Extension Type

  Device extension

Registered Extension Number

  162

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

  - Requires `VK_KHR_maintenance3`

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Jeff Bolz jeffbolznv

Status

  Complete

Last Modified Data

  2017-10-02

Interactions and External Dependencies

  - Promoted to Vulkan 1.2 Core

Contributors

  - Jeff Bolz, NVIDIA

  - Daniel Rakos, AMD

  - Slawomir Grajewski, Intel

  - Tobias Hector, Imagination Technologies

This extension adds several small features which together enable applications to create large descriptor sets containing substantially all of their resources, and selecting amongst those resources with dynamic (non-uniform) indexes in the shader. There are feature enables and SPIR-V capabilities for non-uniform descriptor indexing in the shader, and non-uniform indexing in the shader requires use of a new `NonUniformEXT` decoration defined in the `SPV_EXT_descriptor_indexing` SPIR-V extension. There are descriptor set layout binding creation flags enabling several features:

- Descriptors can be updated after they are bound to a command buffer, such that the execution of the command buffer reflects the most recent update to the descriptors.

- Descriptors that are not used by any pending command buffers can be updated, which enables writing new descriptors for frame N+1 while frame N is executing.

- Relax the requirement that all descriptors in a binding that is “statically used” must be valid, such that descriptors that are not accessed by a submission need not be valid and can be updated while that submission is executing.

- The final binding in a descriptor set layout can have a variable size (and unsized arrays of resources are allowed in the `GL_EXT_nonuniform_qualifier` and `SPV_EXT_descriptor_indexing` extensions).

Note that it is valid for multiple descriptor arrays in a shader to use the same set and binding number, as long as they are all compatible with the descriptor type in the pipeline layout. This means a single array binding in the descriptor set can serve multiple texture dimensionalities, or an array of buffer descriptors can be used with multiple different block layouts.

There are new descriptor set layout and descriptor pool creation flags that are required to opt in to the update-after-bind functionality, and there are separate `maxPerStage`* and `maxDescriptorSet`* limits that apply to these descriptor set layouts which may be much higher than the pre-existing limits. The old limits only count descriptors in non-updateAfterBind descriptor set layouts, and the new limits count descriptors in all descriptor set layouts in the pipeline layout.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_BINDING_FLAGS_CREATE_INFO_EXT`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_FEATURES_EXT`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DESCRIPTOR_INDEXING_PROPERTIES_EXT`

  - `VK_STRUCTURE_TYPE_DESCRIPTOR_SET_VARIABLE_DESCRIPTOR_COUNT_ALLOCATE_INFO_EXT`

  - `VK_STRUCTURE_TYPE_DESCRIPTOR_SET_VARIABLE_DESCRIPTOR_COUNT_LAYOUT_SUPPORT_EXT`

- Extending VkDescriptorPoolCreateFlagBits:

  - `VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT_EXT`

- Extending VkDescriptorSetLayoutCreateFlagBits:

  - `VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT_EXT`

- Extending VkResult:

  - `VK_ERROR_FRAGMENTATION_EXT`

#### New Enums

- VkDescriptorBindingFlagBitsEXT

#### New Structures

- VkDescriptorSetLayoutBindingFlagsCreateInfoEXT

- VkPhysicalDeviceDescriptorIndexingFeaturesEXT

- VkPhysicalDeviceDescriptorIndexingPropertiesEXT

- VkDescriptorSetVariableDescriptorCountAllocateInfoEXT

- VkDescriptorSetVariableDescriptorCountLayoutSupportEXT

#### New Functions

None.

#### Promotion to Vulkan 1.2

Functionality in this extension is included in core Vulkan 1.2, with the EXT suffix omitted. However, if Vulkan 1.2 is supported and this extension is not, the `descriptorIndexing` capability is optional. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

None.

#### Version History

- Revision 1, 2017-07-26 (Jeff Bolz)

  - Internal revisions

- Revision 2, 2017-10-02 (Jeff Bolz)

  - ???

#### VK_EXT_host_query_reset

Name String

  `VK_EXT_host_query_reset`

Extension Type

  Device extension

Registered Extension Number

  262

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Bas Nieuwenhuizen BNieuwenhuizen

Last Modified Date

  2019-03-06

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Promoted to Vulkan 1.2 Core

Contributors

  - Bas Nieuwenhuizen, Google

  - Jason Ekstrand, Intel

  - Jeff Bolz, NVIDIA

  - Piers Daniell, NVIDIA

This extension adds a new function to reset queries from the host.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_HOST_QUERY_RESET_FEATURES_EXT`

#### New Enums

None.

#### New Structures

- VkPhysicalDeviceHostQueryResetFeaturesEXT

#### New Functions

- vkResetQueryPoolEXT

#### Promotion to Vulkan 1.2

All functionality in this extension is included in core Vulkan 1.2, with the EXT suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

#### Version History

- Revision 1, 2019-03-12 (Bas Nieuwenhuizen)

  - Initial draft

#### VK_EXT_sampler_filter_minmax

Name String

  `VK_EXT_sampler_filter_minmax`

Extension Type

  Device extension

Registered Extension Number

  131

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Jeff Bolz jeffbolznv

Last Modified Date

  2017-05-19

Interactions and External Dependencies

  - Promoted to Vulkan 1.2 Core

IP Status

  No known IP claims.

Contributors

  - Jeff Bolz, NVIDIA

  - Piers Daniell, NVIDIA

In unextended Vulkan, minification and magnification filters such as LINEAR allow sampled image lookups to return a filtered texel value produced by computing a weighted average of a collection of texels in the neighborhood of the texture coordinate provided.

This extension provides a new sampler parameter which allows applications to produce a filtered texel value by computing a component-wise minimum (MIN) or maximum (MAX) of the texels that would normally be averaged. The reduction mode is orthogonal to the minification and magnification filter parameters. The filter parameters are used to identify the set of texels used to produce a final filtered value; the reduction mode identifies how these texels are combined.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SAMPLER_FILTER_MINMAX_PROPERTIES_EXT`

  - `VK_STRUCTURE_TYPE_SAMPLER_REDUCTION_MODE_CREATE_INFO_EXT`

- Extending VkFormatFeatureFlagBits

  - `VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_MINMAX_BIT_EXT`

#### New Enums

- VkSamplerReductionModeEXT

#### New Structures

- VkSamplerReductionModeCreateInfoEXT

- VkPhysicalDeviceSamplerFilterMinmaxPropertiesEXT

#### New Functions

None.

#### New Built-In Variables

None.

#### New SPIR-V Capabilities

None.

#### Promotion to Vulkan 1.2

All functionality in this extension is included in core Vulkan 1.2, with the EXT suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

None.

#### Examples

None.

#### Version History

- Revision 2, 2017-05-19 (Piers Daniell)

  - Renamed to EXT

- Revision 1, 2017-03-25 (Jeff Bolz)

  - Internal revisions

#### VK_EXT_scalar_block_layout

Name String

  `VK_EXT_scalar_block_layout`

Extension Type

  Device extension

Registered Extension Number

  222

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_KHR_get_physical_device_properties2`

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Tobias Hector tobski

Last Modified Date

  2018-11-14

Interactions and External Dependencies

  - Promoted to Vulkan 1.2 Core

Contributors

  - Jeff Bolz

  - Jan-Harald Fredriksen

  - Graeme Leese

  - Jason Ekstrand

  - John Kessenich

#### Short Description

Enables C-like structure layout for SPIR-V blocks.

#### Description

This extension modifies the alignment rules for uniform buffers, storage buffers and push constants, allowing non-scalar types to be aligned solely based on the size of their components, without additional requirements.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SCALAR_BLOCK_LAYOUT_FEATURES_EXT`

#### New Structures

- VkPhysicalDeviceScalarBlockLayoutFeaturesEXT

#### Promotion to Vulkan 1.2

Functionality in this extension is included in core Vulkan 1.2, with the EXT suffix omitted. However, if Vulkan 1.2 is supported and this extension is not, the `scalarBlockLayout` capability is optional. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

None.

#### Version History

- Revision 1, 2018-11-14 (Tobias Hector)

  - Initial draft

#### VK_EXT_separate_stencil_usage

Name String

  `VK_EXT_separate_stencil_usage`

Extension Type

  Device extension

Registered Extension Number

  247

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Daniel Rakos drakos-amd

Last Modified Date

  2018-11-08

Interactions and External Dependencies

  - Promoted to Vulkan 1.2 Core

IP Status

  No known IP claims.

Contributors

  - Daniel Rakos, AMD

  - Jordan Logan, AMD

This extension allows specifying separate usage flags for the stencil aspect of images with a depth-stencil format at image creation time.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_IMAGE_STENCIL_USAGE_CREATE_INFO_EXT`

#### New Enums

None.

#### New Structures

- VkImageStencilUsageCreateInfoEXT

#### New Functions

None.

#### Promotion to Vulkan 1.2

All functionality in this extension is included in core Vulkan 1.2, with the EXT suffix omitted. The original type, enum and command names are still available as aliases of the core functionality.

#### Issues

None.

#### Version History

- Revision 1, 2018-11-08 (Daniel Rakos)

  - Internal revisions.

#### VK_EXT_shader_subgroup_ballot

Name String

  `VK_EXT_shader_subgroup_ballot`

Extension Type

  Device extension

Registered Extension Number

  65

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Deprecated by Vulkan 1.2

Contact

  - Daniel Koch dgkoch

Last Modified Date

  2016-11-28

IP Status

  No known IP claims.

Interactions and External Dependencies

  - This extension requires the `SPV_KHR_shader_ballot` SPIR-V extension.

  - This extension requires the `GL_ARB_shader_ballot` extension for GLSL source languages.

Contributors

  - Jeff Bolz, NVIDIA

  - Neil Henning, Codeplay

  - Daniel Koch, NVIDIA Corporation

This extension adds support for the following SPIR-V extension in Vulkan:

- `SPV_KHR_shader_ballot`

This extension provides the ability for a group of invocations, which execute in parallel, to do limited forms of cross-invocation communication via a group broadcast of a invocation value, or broadcast of a bitarray representing a predicate value from each invocation in the group.

This extension provides access to a number of additional built-in shader variables in Vulkan:

- `SubgroupEqMaskKHR`, which contains the subgroup mask of the current subgroup invocation,

- `SubgroupGeMaskKHR`, which contains the subgroup mask of the invocations greater than or equal to the current invocation,

- `SubgroupGtMaskKHR`, which contains the subgroup mask of the invocations greater than the current invocation,

- `SubgroupLeMaskKHR`, which contains the subgroup mask of the invocations less than or equal to the current invocation,

- `SubgroupLtMaskKHR`, which contains the subgroup mask of the invocations less than the current invocation,

- `SubgroupLocalInvocationId`, which contains the index of an invocation within a subgroup, and

- `SubgroupSize`, which contains the maximum number of invocations in a subgroup.

Additionally, this extension provides access to the new SPIR-V instructions:

- `OpSubgroupBallotKHR`,

- `OpSubgroupFirstInvocationKHR`, and

- `OpSubgroupReadInvocationKHR`,

When using GLSL source-based shader languages, the following variables and shader functions from GL_ARB_shader_ballot can map to these SPIR-V built-in decorations and instructions:

- `in uint64_t gl_SubGroupEqMaskARB;` → `SubgroupEqMaskKHR`,

- `in uint64_t gl_SubGroupGeMaskARB;` → `SubgroupGeMaskKHR`,

- `in uint64_t gl_SubGroupGtMaskARB;` → `SubgroupGtMaskKHR`,

- `in uint64_t gl_SubGroupLeMaskARB;` → `SubgroupLeMaskKHR`,

- `in uint64_t gl_SubGroupLtMaskARB;` → `SubgroupLtMaskKHR`,

- `in uint gl_SubGroupInvocationARB;` → `SubgroupLocalInvocationId`,

- `uniform uint gl_SubGroupSizeARB;` → `SubgroupSize`,

- `ballotARB`() → `OpSubgroupBallotKHR`,

- `readFirstInvocationARB`() → `OpSubgroupFirstInvocationKHR`, and

- `readInvocationARB`() → `OpSubgroupReadInvocationKHR`.

#### New Object Types

None.

#### New Enum Constants

None.

#### New Enums

None.

#### New Structures

None.

#### New Functions

None.

#### New Built-In Variables

- `SubgroupEqMaskKHR`

- `SubgroupGeMaskKHR`

- `SubgroupGtMaskKHR`

- `SubgroupLeMaskKHR`

- `SubgroupLtMaskKHR`

- `SubgroupLocalInvocationId`

- `SubgroupSize`

#### New SPIR-V Capabilities

- SubgroupBallotKHR

#### Deprecated by Vulkan 1.2

Most of the functionality in this extension is superseded by the core Vulkan 1.1 subgroup operations. However, Vulkan 1.1 required the `OpGroupNonUniformBroadcast` "Id" to be constant. This restriction was removed in Vulkan 1.2 with the addition of the subgroupBroadcastDynamicId feature.

#### Issues

None.

#### Version History

- Revision 1, 2016-11-28 (Daniel Koch)

  - Initial draft

#### VK_EXT_shader_subgroup_vote

Name String

  `VK_EXT_shader_subgroup_vote`

Extension Type

  Device extension

Registered Extension Number

  66

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Deprecated by Vulkan 1.1

Contact

  - Daniel Koch dgkoch

Last Modified Date

  2016-11-28

IP Status

  No known IP claims.

Interactions and External Dependencies

  - This extension requires the `SPV_KHR_subgroup_vote` SPIR-V extension.

  - This extension requires the `GL_ARB_shader_group_vote` extension for GLSL source languages.

Contributors

  - Neil Henning, Codeplay

  - Daniel Koch, NVIDIA Corporation

This extension adds support for the following SPIR-V extension in Vulkan:

- `SPV_KHR_subgroup_vote`

This extension provides new SPIR-V instructions:

- `OpSubgroupAllKHR`,

- `OpSubgroupAnyKHR`, and

- `OpSubgroupAllEqualKHR`.

to compute the composite of a set of boolean conditions across a group of shader invocations that are running concurrently (a subgroup). These composite results may be used to execute shaders more efficiently on a VkPhysicalDevice.

When using GLSL source-based shader languages, the following shader functions from GL_ARB_shader_group_vote can map to these SPIR-V instructions:

- `anyInvocationARB`() → `OpSubgroupAnyKHR`,

- `allInvocationsARB`() → `OpSubgroupAllKHR`, and

- `allInvocationsEqualARB`() → `OpSubgroupAllEqualKHR`.

The subgroup across which the boolean conditions are evaluated is implementation-dependent, and this extension provides no guarantee over how individual shader invocations are assigned to subgroups. In particular, a subgroup has no necessary relationship with the compute shader local workgroup— any pair of shader invocations in a compute local workgroup may execute in different subgroups as used by these instructions.

Compute shaders operate on an explicitly specified group of threads (a local workgroup), but many implementations will also group non-compute shader invocations and execute them concurrently. When executing code like

    if (condition) {
      result = do_fast_path();
    } else {
      result = do_general_path();
    }

where `condition` diverges between invocations, an implementation might first execute `do_fast_path`() for the invocations where `condition` is true and leave the other invocations dormant. Once `do_fast_path`() returns, it might call `do_general_path`() for invocations where `condition` is `false` and leave the other invocations dormant. In this case, the shader executes both the fast and the general path and might be better off just using the general path for all invocations.

This extension provides the ability to avoid divergent execution by evaluating a condition across an entire subgroup using code like:

    if (allInvocationsARB(condition)) {
      result = do_fast_path();
    } else {
      result = do_general_path();
    }

The built-in function `allInvocationsARB`() will return the same value for all invocations in the group, so the group will either execute `do_fast_path`() or `do_general_path`(), but never both. For example, shader code might want to evaluate a complex function iteratively by starting with an approximation of the result and then refining the approximation. Some input values may require a small number of iterations to generate an accurate result (`do_fast_path`) while others require a larger number (`do_general_path`). In another example, shader code might want to evaluate a complex function (`do_general_path`) that can be greatly simplified when assuming a specific value for one of its inputs (`do_fast_path`).

#### New Object Types

None.

#### New Enum Constants

None.

#### New Enums

None.

#### New Structures

None.

#### New Functions

None.

#### New Built-In Variables

None.

#### New SPIR-V Capabilities

- SubgroupVoteKHR

#### Deprecated by Vulkan 1.1

All functionality in this extension is superseded by the core Vulkan 1.1 subgroup operations.

#### Issues

None.

#### Version History

- Revision 1, 2016-11-28 (Daniel Koch)

  - Initial draft

#### VK_EXT_shader_viewport_index_layer

Name String

  `VK_EXT_shader_viewport_index_layer`

Extension Type

  Device extension

Registered Extension Number

  163

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Promoted to Vulkan 1.2

Contact

  - Daniel Koch dgkoch

Last Modified Date

  2017-08-08

Interactions and External Dependencies

  - Promoted to Vulkan 1.2 Core

Interactions and External Dependencies

  - This extension requires the `SPV_EXT_shader_viewport_index_layer` SPIR-V extension.

  - This extension requires the `GL_ARB_shader_viewport_layer_array`, `GL_AMD_vertex_shader_layer`, `GL_AMD_vertex_shader_viewport_index`, or `GL_NV_viewport_array2` extensions for GLSL source languages.

  - This extension requires the `multiViewport` feature.

  - This extension interacts with the `tessellationShader` feature.

Contributors

  - Piers Daniell, NVIDIA

  - Jeff Bolz, NVIDIA

  - Jan-Harald Fredriksen, ARM

  - Daniel Rakos, AMD

  - Slawomir Grajeswki, Intel

This extension adds support for the `ShaderViewportIndexLayerEXT` capability from the `SPV_EXT_shader_viewport_index_layer` extension in Vulkan.

This extension allows variables decorated with the `Layer` and `ViewportIndex` built-ins to be exported from vertex or tessellation shaders, using the `ShaderViewportIndexLayerEXT` capability.

When using GLSL source-based shading languages, the `gl_ViewportIndex` and `gl_Layer` built-in variables map to the SPIR-V `ViewportIndex` and `Layer` built-in decorations, respectively. Behaviour of these variables is extended as described in the `GL_ARB_shader_viewport_layer_array` (or the precursor `GL_AMD_vertex_shader_layer`, `GL_AMD_vertex_shader_viewport_index`, and `GL_NV_viewport_array2` extensions).

| Note The `ShaderViewportIndexLayerEXT` capability is equivalent to the `ShaderViewportIndexLayerNV` capability added by `VK_NV_viewport_array2`.

#### New Object Types

None.

#### New Enum Constants

None.

#### New Enums

None.

#### New Structures

None.

#### New Functions

None.

#### New or Modified Built-In Variables

- (modified) `Layer`

- (modified) `ViewportIndex`

#### New Variable Decoration

None.

#### New SPIR-V Capabilities

- `ShaderViewportIndexLayerEXT`

#### Promotion to Vulkan 1.2

All functionality in this extension is included in core Vulkan 1.2.

The single `ShaderViewportIndexLayerEXT` capability from the `SPV_EXT_shader_viewport_index_layer` extension is replaced by the `ShaderViewportIndex` and `ShaderLayer` capabilities from SPIR-V 1.5 which are enabled by the shaderOutputViewportIndex and shaderOutputLayer features, respectively. Additionally, if Vulkan 1.2 is supported but this extension is not, these capabilities are optional.

Enabling both features is equivalent to enabling the VK_EXT_shader_viewport_index_layer extension.

#### Issues

None yet!

#### Version History

- Revision 1, 2017-08-08 (Daniel Koch)

  - Internal drafts

#### VK_EXT_validation_flags

Name String

  `VK_EXT_validation_flags`

Extension Type

  Instance extension

Registered Extension Number

  62

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Deprecated by `VK_EXT_validation_features` extension

Contact

  - Tobin Ehlis tobine

Last Modified Date

  2019-08-19

IP Status

  No known IP claims.

Contributors

  - Tobin Ehlis, Google

  - Courtney Goeltzenleuchter, Google

This extension provides the VkValidationFlagsEXT struct that can be included in the `pNext` chain of the VkInstanceCreateInfo structure passed as the `pCreateInfo` parameter of vkCreateInstance. The structure contains an array of VkValidationCheckEXT values that will be disabled by the validation layers.

#### Deprecation by VK_EXT_validation_features

Functionality in this extension is subsumed into the `VK_EXT_validation_features` extension.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_VALIDATION_FLAGS_EXT`

#### New Enums

- VkValidationCheckEXT

#### New Structures

- VkValidationFlagsEXT

#### New Functions

None.

#### Issues

None.

#### Version History

- Revision 2, 2019-08-19 (Mark Lobodzinski)

  - Marked as deprecated

- Revision 1, 2016-08-26 (Courtney Goeltzenleuchter)

  - Initial draft

#### VK_AMD_draw_indirect_count

Name String

  `VK_AMD_draw_indirect_count`

Extension Type

  Device extension

Registered Extension Number

  34

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Promoted to `VK_KHR_draw_indirect_count` extension

    - Which in turn was promoted to Vulkan 1.2

Contact

  - Daniel Rakos drakos-amd

Last Modified Date

  2016-08-23

Interactions and External Dependencies

  - Promoted to VK_KHR_draw_indirect_count

IP Status

  No known IP claims.

Contributors

  - Matthaeus G. Chajdas, AMD

  - Derrick Owens, AMD

  - Graham Sellers, AMD

  - Daniel Rakos, AMD

  - Dominik Witczak, AMD

This extension allows an application to source the number of draw calls for indirect draw calls from a buffer. This enables applications to generate arbitrary amounts of draw commands and execute them without host intervention.

#### New Functions

- vkCmdDrawIndirectCountAMD

- vkCmdDrawIndexedIndirectCountAMD

#### Promotion to VK_KHR_draw_indirect_count

All functionality in this extension is included in `VK_KHR_draw_indirect_count`, with the suffix changed to KHR. The original type, enum and command names are still available as aliases of the core functionality.

#### Version History

- Revision 2, 2016-08-23 (Dominik Witczak)

  - Minor fixes

- Revision 1, 2016-07-21 (Matthaeus Chajdas)

  - Initial draft

#### VK_AMD_gpu_shader_half_float

Name String

  `VK_AMD_gpu_shader_half_float`

Extension Type

  Device extension

Registered Extension Number

  37

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Deprecated by `VK_KHR_shader_float16_int8` extension

    - Which in turn was promoted to Vulkan 1.2

Contact

  - Dominik Witczak dominikwitczakamd

Last Modified Date

  2019-04-11

IP Status

  No known IP claims.

Contributors

  - Daniel Rakos, AMD

  - Dominik Witczak, AMD

  - Donglin Wei, AMD

  - Graham Sellers, AMD

  - Qun Lin, AMD

  - Rex Xu, AMD

External Dependencies

  - `SPV_AMD_gpu_shader_half_float`

This extension adds support for using half float variables in shaders.

#### Deprecation by VK_KHR_shader_float16_int8

Functionality in this extension was included in `VK_KHR_shader_float16_int8` extension, when VkPhysicalDeviceShaderFloat16Int8FeaturesKHR::`shaderFloat16` is enabled.

#### Version History

- Revision 2, 2019-04-11 (Tobias Hector)

  - Marked as deprecated

- Revision 1, 2016-09-21 (Dominik Witczak)

  - Initial draft

#### VK_AMD_gpu_shader_int16

Name String

  `VK_AMD_gpu_shader_int16`

Extension Type

  Device extension

Registered Extension Number

  133

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Deprecated by `VK_KHR_shader_float16_int8` extension

    - Which in turn was promoted to Vulkan 1.2

Contact

  - Qun Lin linqun

Last Modified Date

  2019-04-11

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Requires the `SPV_AMD_gpu_shader_int16` SPIR-V extension.

Contributors

  - Daniel Rakos, AMD

  - Dominik Witczak, AMD

  - Matthaeus G. Chajdas, AMD

  - Rex Xu, AMD

  - Timothy Lottes, AMD

  - Zhi Cai, AMD

External Dependencies

  - `SPV_AMD_gpu_shader_int16`

This extension adds support for using 16-bit integer variables in shaders.

#### Deprecation by VK_KHR_shader_float16_int8

Functionality in this extension was included in `VK_KHR_shader_float16_int8` extension, when VkPhysicalDeviceFeatures::`shaderInt16` and VkPhysicalDeviceShaderFloat16Int8FeaturesKHR::`shaderFloat16` are enabled.

#### Version History

- Revision 2, 2019-04-11 (Tobias Hector)

  - Marked as deprecated

- Revision 1, 2017-06-18 (Dominik Witczak)

  - First version

#### VK_AMD_negative_viewport_height

Name String

  `VK_AMD_negative_viewport_height`

Extension Type

  Device extension

Registered Extension Number

  36

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Obsoleted by `VK_KHR_maintenance1` extension

    - Which in turn was promoted to Vulkan 1.1

Contact

  - Matthaeus G. Chajdas anteru

Last Modified Date

  2016-09-02

IP Status

  No known IP claims.

Contributors

  - Matthaeus G. Chajdas, AMD

  - Graham Sellers, AMD

  - Baldur Karlsson

This extension allows an application to specify a negative viewport height. The result is that the viewport transformation will flip along the y-axis.

- Allow negative height to be specified in the VkViewport::`height` field to perform y-inversion of the clip-space to framebuffer-space transform. This allows apps to avoid having to use `gl_Position.y = -gl_Position.y` in shaders also targeting other APIs.

#### Obsoletion by VK_KHR_maintenance1 and Vulkan 1.1

Functionality in this extension is included in `VK_KHR_maintenance1` and subsequently Vulkan 1.1. Due to some slight behavioral differences, this extension must not be enabled alongside `VK_KHR_maintenance1`, or in an instance created with version 1.1 or later requested in VkApplicationInfo::`apiVersion`.

#### Version History

- Revision 1, 2016-09-02 (Matthaeus Chajdas)

  - Initial draft

#### VK_NV_dedicated_allocation

Name String

  `VK_NV_dedicated_allocation`

Extension Type

  Device extension

Registered Extension Number

  27

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Deprecated by `VK_KHR_dedicated_allocation` extension

    - Which in turn was promoted to Vulkan 1.1

Contact

  - Jeff Bolz jeffbolznv

Last Modified Date

  2016-05-31

IP Status

  No known IP claims.

Contributors

  - Jeff Bolz, NVIDIA

This extension allows device memory to be allocated for a particular buffer or image resource, which on some devices can significantly improve the performance of that resource. Normal device memory allocations must support memory aliasing and sparse binding, which could interfere with optimizations like framebuffer compression or efficient page table usage. This is important for render targets and very large resources, but need not (and probably should not) be used for smaller resources that can benefit from suballocation.

This extension adds a few small structures to resource creation and memory allocation: a new structure that flags whether am image/buffer will have a dedicated allocation, and a structure indicating the image or buffer that an allocation will be bound to.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_IMAGE_CREATE_INFO_NV`

  - `VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_BUFFER_CREATE_INFO_NV`

  - `VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_MEMORY_ALLOCATE_INFO_NV`

#### New Enums

None.

#### New Structures

- VkDedicatedAllocationImageCreateInfoNV

- VkDedicatedAllocationBufferCreateInfoNV

- VkDedicatedAllocationMemoryAllocateInfoNV

#### New Functions

None.

#### Issues

None.

#### Examples

        // Create an image with
        // VkDedicatedAllocationImageCreateInfoNV::dedicatedAllocation
        // set to VK_TRUE

        VkDedicatedAllocationImageCreateInfoNV dedicatedImageInfo =
        {
            VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_IMAGE_CREATE_INFO_NV,            // sType
            NULL,                                                                   // pNext
            VK_TRUE,                                                                // dedicatedAllocation
        };

        VkImageCreateInfo imageCreateInfo =
        {
            VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO,    // sType
            &dedicatedImageInfo                     // pNext
            // Other members set as usual
        };

        VkImage image;
        VkResult result = vkCreateImage(
            device,
            &imageCreateInfo,
            NULL,                       // pAllocator
            &image);

        VkMemoryRequirements memoryRequirements;
        vkGetImageMemoryRequirements(
            device,
            image,
            &memoryRequirements);

        // Allocate memory with VkDedicatedAllocationMemoryAllocateInfoNV::image
        // pointing to the image we are allocating the memory for

        VkDedicatedAllocationMemoryAllocateInfoNV dedicatedInfo =
        {
            VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_MEMORY_ALLOCATE_INFO_NV,             // sType
            NULL,                                                                       // pNext
            image,                                                                      // image
            VK_NULL_HANDLE,                                                             // buffer
        };

        VkMemoryAllocateInfo memoryAllocateInfo =
        {
            VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO,                 // sType
            &dedicatedInfo,                                         // pNext
            memoryRequirements.size,                                // allocationSize
            FindMemoryTypeIndex(memoryRequirements.memoryTypeBits), // memoryTypeIndex
        };

        VkDeviceMemory memory;
        vkAllocateMemory(
            device,
            &memoryAllocateInfo,
            NULL,                       // pAllocator
            &memory);

        // Bind the image to the memory

        vkBindImageMemory(
            device,
            image,
            memory,
            0);

#### Version History

- Revision 1, 2016-05-31 (Jeff Bolz)

  - Internal revisions

#### VK_NV_external_memory

Name String

  `VK_NV_external_memory`

Extension Type

  Device extension

Registered Extension Number

  57

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_NV_external_memory_capabilities`

Deprecation state

  - Deprecated by `VK_KHR_external_memory` extension

    - Which in turn was promoted to Vulkan 1.1

Contact

  - James Jones cubanismo

Last Modified Date

  2016-08-19

IP Status

  No known IP claims.

Contributors

  - James Jones, NVIDIA

  - Carsten Rohde, NVIDIA

Applications may wish to export memory to other Vulkan instances or other APIs, or import memory from other Vulkan instances or other APIs to enable Vulkan workloads to be split up across application module, process, or API boundaries. This extension enables applications to create exportable Vulkan memory objects such that the underlying resources can be referenced outside the Vulkan instance that created them.

#### New Object Types

None.

#### New Enum Constants

Extending VkStructureType:

- `VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_IMAGE_CREATE_INFO_NV`

- `VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO_NV`

#### New Enums

None.

#### New Structures

- Extending VkImageCreateInfo:

  - VkExternalMemoryImageCreateInfoNV

- Extending VkMemoryAllocateInfo

  - VkExportMemoryAllocateInfoNV

#### New Functions

None.

#### Issues

1) If memory objects are shared between processes and APIs, is this considered aliasing according to the rules outlined in the Memory Aliasing section?

RESOLVED: Yes, but strict exceptions to the rules are added to allow some forms of aliasing in these cases. Further, other extensions may build upon these new aliasing rules to define specific support usage within Vulkan for imported native memory objects, or memory objects from other APIs.

2) Are new image layouts or metadata required to specify image layouts and layout transitions compatible with non-Vulkan APIs, or with other instances of the same Vulkan driver?

RESOLVED: No. Separate instances of the same Vulkan driver running on the same GPU should have identical internal layout semantics, so applictions have the tools they need to ensure views of images are consistent between the two instances. Other APIs will fall into two categories: Those that are Vulkan compatible (a term to be defined by subsequent interopability extensions), or Vulkan incompatible. When sharing images with Vulkan incompatible APIs, the Vulkan image must be transitioned to the `VK_IMAGE_LAYOUT_GENERAL` layout before handing it off to the external API.

Note this does not attempt to address cross-device transitions, nor transitions to engines on the same device which are not visible within the Vulkan API. Both of these are beyond the scope of this extension.

#### Examples

        // TODO: Write some sample code here.

#### Version History

- Revision 1, 2016-08-19 (James Jones)

  - Initial draft

#### VK_NV_external_memory_capabilities

Name String

  `VK_NV_external_memory_capabilities`

Extension Type

  Instance extension

Registered Extension Number

  56

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Deprecated by `VK_KHR_external_memory_capabilities` extension

    - Which in turn was promoted to Vulkan 1.1

Contact

  - James Jones cubanismo

Last Modified Date

  2016-08-19

IP Status

  No known IP claims.

Interactions and External Dependencies

  - Interacts with Vulkan 1.1.

  - Interacts with `VK_KHR_dedicated_allocation`.

  - Interacts with `VK_NV_dedicated_allocation`.

Contributors

  - James Jones, NVIDIA

Applications may wish to import memory from the Direct 3D API, or export memory to other Vulkan instances. This extension provides a set of capability queries that allow applications determine what types of win32 memory handles an implementation supports for a given set of use cases.

#### New Object Types

None.

#### New Enum Constants

None.

#### New Enums

- VkExternalMemoryHandleTypeFlagBitsNV

- VkExternalMemoryFeatureFlagBitsNV

#### New Structs

- VkExternalImageFormatPropertiesNV

#### New Functions

- vkGetPhysicalDeviceExternalImageFormatPropertiesNV

#### Issues

1) Why do so many external memory capabilities need to be queried on a per-memory-handle-type basis?

RESOLVED: This is because some handle types are based on OS-native objects that have far more limited capabilities than the very generic Vulkan memory objects. Not all memory handle types can name memory objects that support 3D images, for example. Some handle types cannot even support the deferred image and memory binding behavior of Vulkan and require specifying the image when allocating or importing the memory object.

2) Does the VkExternalImageFormatPropertiesNV struct need to include a list of memory type bits that support the given handle type?

RESOLVED: No. The memory types that do not support the handle types will simply be filtered out of the results returned by vkGetImageMemoryRequirements when a set of handle types was specified at image creation time.

3) Should the non-opaque handle types be moved to their own extension?

RESOLVED: Perhaps. However, defining the handle type bits does very little and does not require any platform-specific types on its own, and it is easier to maintain the bitmask values in a single extension for now. Presumably more handle types could be added by separate extensions though, and it would be midly weird to have some platform-specific ones defined in the core spec and some in extensions

#### Version History

- Revision 1, 2016-08-19 (James Jones)

  - Initial version

#### VK_NV_external_memory_win32

Name String

  `VK_NV_external_memory_win32`

Extension Type

  Device extension

Registered Extension Number

  58

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_NV_external_memory`

Deprecation state

  - Deprecated by `VK_KHR_external_memory_win32` extension

Contact

  - James Jones cubanismo

Last Modified Date

  2016-08-19

IP Status

  No known IP claims.

Contributors

  - James Jones, NVIDIA

  - Carsten Rohde, NVIDIA

Applications may wish to export memory to other Vulkan instances or other APIs, or import memory from other Vulkan instances or other APIs to enable Vulkan workloads to be split up across application module, process, or API boundaries. This extension enables win32 applications to export win32 handles from Vulkan memory objects such that the underlying resources can be referenced outside the Vulkan instance that created them, and import win32 handles created in the Direct3D API to Vulkan memory objects.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_IMPORT_MEMORY_WIN32_HANDLE_INFO_NV`

  - `VK_STRUCTURE_TYPE_EXPORT_MEMORY_WIN32_HANDLE_INFO_NV`

#### New Enums

None.

#### New Structures

- Extending VkMemoryAllocateInfo

  - VkImportMemoryWin32HandleInfoNV

- Extends VkMemoryAllocateInfo

  - VkExportMemoryWin32HandleInfoNV

#### New Functions

- vkGetMemoryWin32HandleNV

#### Issues

1) If memory objects are shared between processes and APIs, is this considered aliasing according to the rules outlined in the Memory Aliasing section?

RESOLVED: Yes, but strict exceptions to the rules are added to allow some forms of aliasing in these cases. Further, other extensions may build upon these new aliasing rules to define specific support usage within Vulkan for imported native memory objects, or memory objects from other APIs.

2) Are new image layouts or metadata required to specify image layouts and layout transitions compatible with non-Vulkan APIs, or with other instances of the same Vulkan driver?

RESOLVED: No. Separate instances of the same Vulkan driver running on the same GPU should have identical internal layout semantics, so applictions have the tools they need to ensure views of images are consistent between the two instances. Other APIs will fall into two categories: Those that are Vulkan compatible (a term to be defined by subsequent interopability extensions), or Vulkan incompatible. When sharing images with Vulkan incompatible APIs, the Vulkan image must be transitioned to the `VK_IMAGE_LAYOUT_GENERAL` layout before handing it off to the external API.

Note this does not attempt to address cross-device transitions, nor transitions to engines on the same device which are not visible within the Vulkan API. Both of these are beyond the scope of this extension.

3) Do applications need to call `CloseHandle`() on the values returned from vkGetMemoryWin32HandleNV when `handleType` is `VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT_NV`?

RESOLVED: Yes, unless it is passed back in to another driver instance to import the object. A successful get call transfers ownership of the handle to the application, while an import transfers ownership to the associated driver. Destroying the memory object will not destroy the handle or the handle’s reference to the underlying memory resource.

#### Examples

        //
        // Create an exportable memory object and export an external
        // handle from it.
        //

        // Pick an external format and handle type.
        static const VkFormat format = VK_FORMAT_R8G8B8A8_UNORM;
        static const VkExternalMemoryHandleTypeFlagsNV handleType =
            VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_WIN32_BIT_NV;

        extern VkPhysicalDevice physicalDevice;
        extern VkDevice device;

        VkPhysicalDeviceMemoryProperties memoryProperties;
        VkExternalImageFormatPropertiesNV properties;
        VkExternalMemoryImageCreateInfoNV externalMemoryImageCreateInfo;
        VkDedicatedAllocationImageCreateInfoNV dedicatedImageCreateInfo;
        VkImageCreateInfo imageCreateInfo;
        VkImage image;
        VkMemoryRequirements imageMemoryRequirements;
        uint32_t numMemoryTypes;
        uint32_t memoryType;
        VkExportMemoryAllocateInfoNV exportMemoryAllocateInfo;
        VkDedicatedAllocationMemoryAllocateInfoNV dedicatedAllocationInfo;
        VkMemoryAllocateInfo memoryAllocateInfo;
        VkDeviceMemory memory;
        VkResult result;
        HANDLE memoryHnd;

        // Figure out how many memory types the device supports
        vkGetPhysicalDeviceMemoryProperties(physicalDevice,
                                            &memoryProperties);
        numMemoryTypes = memoryProperties.memoryTypeCount;

        // Check the external handle type capabilities for the chosen format
        // Exportable 2D image support with at least 1 mip level, 1 array
        // layer, and VK_SAMPLE_COUNT_1_BIT using optimal tiling and supporting
        // texturing and color rendering is required.
        result = vkGetPhysicalDeviceExternalImageFormatPropertiesNV(
            physicalDevice,
            format,
            VK_IMAGE_TYPE_2D,
            VK_IMAGE_TILING_OPTIMAL,
            VK_IMAGE_USAGE_SAMPLED_BIT |
            VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT,
            0,
            handleType,
            &properties);

        if ((result != VK_SUCCESS) ||
            !(properties.externalMemoryFeatures &
              VK_EXTERNAL_MEMORY_FEATURE_EXPORTABLE_BIT_NV)) {
            abort();
        }

        // Set up the external memory image creation info
        memset(&externalMemoryImageCreateInfo,
               0, sizeof(externalMemoryImageCreateInfo));
        externalMemoryImageCreateInfo.sType =
            VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_IMAGE_CREATE_INFO_NV;
        externalMemoryImageCreateInfo.handleTypes = handleType;
        if (properties.externalMemoryFeatures &
            VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT_NV) {
            memset(&dedicatedImageCreateInfo, 0, sizeof(dedicatedImageCreateInfo));
            dedicatedImageCreateInfo.sType =
                VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_IMAGE_CREATE_INFO_NV;
            dedicatedImageCreateInfo.dedicatedAllocation = VK_TRUE;
            externalMemoryImageCreateInfo.pNext = &dedicatedImageCreateInfo;
        }
        // Set up the  core image creation info
        memset(&imageCreateInfo, 0, sizeof(imageCreateInfo));
        imageCreateInfo.sType = VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO;
        imageCreateInfo.pNext = &externalMemoryImageCreateInfo;
        imageCreateInfo.format = format;
        imageCreateInfo.extent.width = 64;
        imageCreateInfo.extent.height = 64;
        imageCreateInfo.extent.depth = 1;
        imageCreateInfo.mipLevels = 1;
        imageCreateInfo.arrayLayers = 1;
        imageCreateInfo.samples = VK_SAMPLE_COUNT_1_BIT;
        imageCreateInfo.tiling = VK_IMAGE_TILING_OPTIMAL;
        imageCreateInfo.usage = VK_IMAGE_USAGE_SAMPLED_BIT |
            VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT;
        imageCreateInfo.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
        imageCreateInfo.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;

        vkCreateImage(device, &imageCreateInfo, NULL, &image);

        vkGetImageMemoryRequirements(device,
                                     image,
                                     &imageMemoryRequirements);

        // For simplicity, just pick the first compatible memory type.
        for (memoryType = 0; memoryType < numMemoryTypes; memoryType++) {
            if ((1 << memoryType) & imageMemoryRequirements.memoryTypeBits) {
                break;
            }
        }

        // At least one memory type must be supported given the prior external
        // handle capability check.
        assert(memoryType < numMemoryTypes);

        // Allocate the external memory object.
        memset(&exportMemoryAllocateInfo, 0, sizeof(exportMemoryAllocateInfo));
        exportMemoryAllocateInfo.sType =
            VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO_NV;
        exportMemoryAllocateInfo.handleTypes = handleType;
        if (properties.externalMemoryFeatures &
            VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT_NV) {
            memset(&dedicatedAllocationInfo, 0, sizeof(dedicatedAllocationInfo));
            dedicatedAllocationInfo.sType =
                VK_STRUCTURE_TYPE_DEDICATED_ALLOCATION_MEMORY_ALLOCATE_INFO_NV;
            dedicatedAllocationInfo.image = image;
            exportMemoryAllocateInfo.pNext = &dedicatedAllocationInfo;
        }
        memset(&memoryAllocateInfo, 0, sizeof(memoryAllocateInfo));
        memoryAllocateInfo.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO;
        memoryAllocateInfo.pNext = &exportMemoryAllocateInfo;
        memoryAllocateInfo.allocationSize = imageMemoryRequirements.size;
        memoryAllocateInfo.memoryTypeIndex = memoryType;

        vkAllocateMemory(device, &memoryAllocateInfo, NULL, &memory);

        if (!(properties.externalMemoryFeatures &
              VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT_NV)) {
            vkBindImageMemory(device, image, memory, 0);
        }

        // Get the external memory opaque FD handle
        vkGetMemoryWin32HandleNV(device, memory, &memoryHnd);

#### Version History

- Revision 1, 2016-08-11 (James Jones)

  - Initial draft

#### VK_NV_glsl_shader

Name String

  `VK_NV_glsl_shader`

Extension Type

  Device extension

Registered Extension Number

  13

Revision

  1

Extension and Version Dependencies

  - Requires Vulkan 1.0

Deprecation state

  - Deprecated without replacement

Contact

  - Piers Daniell pdaniell-nv

Last Modified Date

  2016-02-14

IP Status

  No known IP claims.

Contributors

  - Piers Daniell, NVIDIA

This extension allows GLSL shaders written to the `GL_KHR_vulkan_glsl` extension specification to be used instead of SPIR-V. The implementation will automatically detect whether the shader is SPIR-V or GLSL, and compile it appropriately.

#### New Enum Constants

- Extending VkResult:

  - `VK_ERROR_INVALID_SHADER_NV`

#### Deprecation

Functionality in this extension is outside of the scope of Vulkan and is better served by a compiler library such as glslang. No new implementations will support this extension, so applications should not use it.

#### Examples

Example 1

Passing in GLSL code

        char const vss[] =
            "#version 450 core\n"
            "layout(location = 0) in vec2 aVertex;\n"
            "layout(location = 1) in vec4 aColor;\n"
            "out vec4 vColor;\n"
            "void main()\n"
            "{\n"
            "    vColor = aColor;\n"
            "    gl_Position = vec4(aVertex, 0, 1);\n"
            "}\n"
        ;
        VkShaderModuleCreateInfo vertexShaderInfo = { VK_STRUCTURE_TYPE_SHADER_MODULE_CREATE_INFO };
        vertexShaderInfo.codeSize = sizeof vss;
        vertexShaderInfo.pCode = vss;
        VkShaderModule vertexShader;
        vkCreateShaderModule(device, &vertexShaderInfo, 0, &vertexShader);

#### Version History

- Revision 1, 2016-02-14 (Piers Daniell)

  - Initial draft

#### VK_NV_win32_keyed_mutex

Name String

  `VK_NV_win32_keyed_mutex`

Extension Type

  Device extension

Registered Extension Number

  59

Revision

  2

Extension and Version Dependencies

  - Requires Vulkan 1.0

  - Requires `VK_NV_external_memory_win32`

Deprecation state

  - Promoted to `VK_KHR_win32_keyed_mutex` extension

Contact

  - Carsten Rohde crohde

Last Modified Date

  2016-08-19

IP Status

  No known IP claims.

Contributors

  - James Jones, NVIDIA

  - Carsten Rohde, NVIDIA

Applications that wish to import Direct3D 11 memory objects into the Vulkan API may wish to use the native keyed mutex mechanism to synchronize access to the memory between Vulkan and Direct3D. This extension provides a way for an application to access the keyed mutex associated with an imported Vulkan memory object when submitting command buffers to a queue.

#### New Object Types

None.

#### New Enum Constants

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_WIN32_KEYED_MUTEX_ACQUIRE_RELEASE_INFO_NV`

#### New Enums

None.

#### New Structures

- Extending VkSubmitInfo:

  - VkWin32KeyedMutexAcquireReleaseInfoNV

#### New Functions

None.

#### Issues

None.

#### Examples

        //
        // Import a memory object from Direct3D 11, and synchronize
        // access to it in Vulkan using keyed mutex objects.
        //

        extern VkPhysicalDevice physicalDevice;
        extern VkDevice device;
        extern HANDLE sharedNtHandle;

        static const VkFormat format = VK_FORMAT_R8G8B8A8_UNORM;
        static const VkExternalMemoryHandleTypeFlagsNV handleType =
            VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_IMAGE_BIT_NV;

        VkPhysicalDeviceMemoryProperties memoryProperties;
        VkExternalImageFormatPropertiesNV properties;
        VkExternalMemoryImageCreateInfoNV externalMemoryImageCreateInfo;
        VkImageCreateInfo imageCreateInfo;
        VkImage image;
        VkMemoryRequirements imageMemoryRequirements;
        uint32_t numMemoryTypes;
        uint32_t memoryType;
        VkImportMemoryWin32HandleInfoNV importMemoryInfo;
        VkMemoryAllocateInfo memoryAllocateInfo;
        VkDeviceMemory mem;
        VkResult result;

        // Figure out how many memory types the device supports
        vkGetPhysicalDeviceMemoryProperties(physicalDevice,
                                            &memoryProperties);
        numMemoryTypes = memoryProperties.memoryTypeCount;

        // Check the external handle type capabilities for the chosen format
        // Importable 2D image support with at least 1 mip level, 1 array
        // layer, and VK_SAMPLE_COUNT_1_BIT using optimal tiling and supporting
        // texturing and color rendering is required.
        result = vkGetPhysicalDeviceExternalImageFormatPropertiesNV(
            physicalDevice,
            format,
            VK_IMAGE_TYPE_2D,
            VK_IMAGE_TILING_OPTIMAL,
            VK_IMAGE_USAGE_SAMPLED_BIT |
            VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT,
            0,
            handleType,
            &properties);

        if ((result != VK_SUCCESS) ||
            !(properties.externalMemoryFeatures &
              VK_EXTERNAL_MEMORY_FEATURE_IMPORTABLE_BIT_NV)) {
            abort();
        }

        // Set up the external memory image creation info
        memset(&externalMemoryImageCreateInfo,
               0, sizeof(externalMemoryImageCreateInfo));
        externalMemoryImageCreateInfo.sType =
            VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_IMAGE_CREATE_INFO_NV;
        externalMemoryImageCreateInfo.handleTypes = handleType;
        // Set up the  core image creation info
        memset(&imageCreateInfo, 0, sizeof(imageCreateInfo));
        imageCreateInfo.sType = VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO;
        imageCreateInfo.pNext = &externalMemoryImageCreateInfo;
        imageCreateInfo.format = format;
        imageCreateInfo.extent.width = 64;
        imageCreateInfo.extent.height = 64;
        imageCreateInfo.extent.depth = 1;
        imageCreateInfo.mipLevels = 1;
        imageCreateInfo.arrayLayers = 1;
        imageCreateInfo.samples = VK_SAMPLE_COUNT_1_BIT;
        imageCreateInfo.tiling = VK_IMAGE_TILING_OPTIMAL;
        imageCreateInfo.usage = VK_IMAGE_USAGE_SAMPLED_BIT |
            VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT;
        imageCreateInfo.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
        imageCreateInfo.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;

        vkCreateImage(device, &imageCreateInfo, NULL, &image);
        vkGetImageMemoryRequirements(device,
                                     image,
                                     &imageMemoryRequirements);

        // For simplicity, just pick the first compatible memory type.
        for (memoryType = 0; memoryType < numMemoryTypes; memoryType++) {
            if ((1 << memoryType) & imageMemoryRequirements.memoryTypeBits) {
                break;
            }
        }

        // At least one memory type must be supported given the prior external
        // handle capability check.
        assert(memoryType < numMemoryTypes);

        // Allocate the external memory object.
        memset(&exportMemoryAllocateInfo, 0, sizeof(exportMemoryAllocateInfo));
        exportMemoryAllocateInfo.sType =
            VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO_NV;
        importMemoryInfo.handleTypes = handleType;
        importMemoryInfo.handle = sharedNtHandle;

        memset(&memoryAllocateInfo, 0, sizeof(memoryAllocateInfo));
        memoryAllocateInfo.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO;
        memoryAllocateInfo.pNext = &exportMemoryAllocateInfo;
        memoryAllocateInfo.allocationSize = imageMemoryRequirements.size;
        memoryAllocateInfo.memoryTypeIndex = memoryType;

        vkAllocateMemory(device, &memoryAllocateInfo, NULL, &mem);

        vkBindImageMemory(device, image, mem, 0);

        ...

        const uint64_t acquireKey = 1;
        const uint32_t timeout = INFINITE;
        const uint64_t releaseKey = 2;

        VkWin32KeyedMutexAcquireReleaseInfoNV keyedMutex =
            { VK_STRUCTURE_TYPE_WIN32_KEYED_MUTEX_ACQUIRE_RELEASE_INFO_NV };
        keyedMutex.acquireCount = 1;
        keyedMutex.pAcquireSyncs = &mem;
        keyedMutex.pAcquireKeys = &acquireKey;
        keyedMutex.pAcquireTimeoutMilliseconds = &timeout;
        keyedMutex.releaseCount = 1;
        keyedMutex.pReleaseSyncs = &mem;
        keyedMutex.pReleaseKeys = &releaseKey;

        VkSubmitInfo submit_info = { VK_STRUCTURE_TYPE_SUBMIT_INFO, &keyedMutex };
        submit_info.commandBufferCount = 1;
        submit_info.pCommandBuffers = &cmd_buf;
        vkQueueSubmit(queue, 1, &submit_info, VK_NULL_HANDLE);

#### Version History

- Revision 2, 2016-08-11 (James Jones)

  - Updated sample code based on the NV external memory extensions.

  - Renamed from NVX to NV extension.

  - Added Overview and Description sections.

  - Updated sample code to use the NV external memory extensions.

- Revision 1, 2016-06-14 (Carsten Rohde)

  - Initial draft.

## Appendix F: API Boilerplate

This appendix defines Vulkan API features that are infrastructure required for a complete functional description of Vulkan, but do not logically belong elsewhere in the Specification.

### Vulkan Header Files

Vulkan is defined as an API in the C99 language. Khronos provides a corresponding set of header files for applications using the API, which may be used in either C or C++ code. The interface descriptions in the specification are the same as the interfaces defined in these header files, and both are derived from the `vk.xml` XML API Registry, which is the canonical machine-readable description of the Vulkan API. The Registry, scripts used for processing it into various forms, and documentation of the registry schema are available as described at https://www.khronos.org/registry/vulkan/#apiregistry .

Language bindings for other languages can be defined using the information in the Specification and the Registry. Khronos does not provide any such bindings, but third-party developers have created some additional bindings.

#### Vulkan Combined API Header `vulkan.h` (Informative)

Applications normally will include the header `vulkan.h`. In turn, `vulkan.h` always includes the following headers:

- `vk_platform.h`, defining platform-specific macros and headers.

- `vulkan_core.h`, defining APIs for the Vulkan core and all registered extensions other than window system-specific and provisional extensions, which are included in separate header files.

In addition, specific preprocessor macros defined at the time `vulkan.h` is included cause header files for the corresponding window system-specific and provisional interfaces to be included, as described below.

#### Vulkan Platform-Specific Header `vk_platform.h` (Informative)

Platform-specific macros and interfaces are defined in `vk_platform.h`. These macros are used to control platform-dependent behavior, and their exact definitions are under the control of specific platforms and Vulkan implementations.

##### Platform-Specific Calling Conventions

On many platforms the following macros are empty strings, causing platform- and compiler-specific default calling conventions to be used.

`VKAPI_ATTR` is a macro placed before the return type in Vulkan API function declarations. This macro controls calling conventions for C++11 and GCC/Clang-style compilers.

`VKAPI_CALL` is a macro placed after the return type in Vulkan API function declarations. This macro controls calling conventions for MSVC-style compilers.

`VKAPI_PTR` is a macro placed between the '(' and '*' in Vulkan API function pointer declarations. This macro also controls calling conventions, and typically has the same definition as `VKAPI_ATTR` or `VKAPI_CALL`, depending on the compiler.

With these macros, a Vulkan function declaration takes the form of:

    VKAPI_ATTR <return_type> VKAPI_CALL <command_name>(<command_parameters>);

Additionally, a Vulkan function pointer type declaration takes the form of:

    typedef <return_type> (VKAPI_PTR *PFN_<command_name>)(<command_parameters>);

##### Platform-Specific Header Control

If the `VK_NO_STDINT_H` macro is defined by the application at compile time, extended integer types used by the Vulkan API, such as `uint8_t`, must also be defined by the application. Otherwise, the Vulkan headers will not compile. If `VK_NO_STDINT_H` is not defined, the system `<stdint.h>` is used to define these types. There is a fallback path when Microsoft Visual Studio version 2008 and earlier versions are detected at compile time.

#### Vulkan Core API Header `vulkan_core.h`

Applications that do not make use of window system-specific extensions may simply include `vulkan_core.h` instead of `vulkan.h`, although there is usually no reason to do so. In addition to the Vulkan API, `vulkan_core.h` also defines a small number of C preprocessor macros that are described below.

##### Vulkan Header File Version Number

`VK_HEADER_VERSION` is the version number of the `vulkan_core.h` header. This value is kept synchronized with the patch version of the released Specification.

    // Version of this file
    #define VK_HEADER_VERSION 135

`VK_HEADER_VERSION_COMPLETE` is the complete version number of the `vulkan_core.h` header, comprising the major, minor, and patch versions. The major/minor values are kept synchronized with the complete version of the released Specification. This value is intended for use by automated tools to identify exactly which version of the header was used during their generation.

Applications should not use this value as their VkApplicationInfo::`apiVersion`. Instead applications should explicitly select a specific fixed major/minor API version using, for example, one of the `VK_API_VERSION_`*_* values.

    // Complete version of this file
    #define VK_HEADER_VERSION_COMPLETE VK_MAKE_VERSION(1, 2, VK_HEADER_VERSION)

`VK_API_VERSION` is now commented out of `vulkan_core.h` and cannot be used.

    // DEPRECATED: This define has been removed. Specific version defines (e.g. VK_API_VERSION_1_0), or the VK_MAKE_VERSION macro, should be used instead.
    //#define VK_API_VERSION VK_MAKE_VERSION(1, 0, 0) // Patch version should always be set to 0

##### Vulkan Handle Macros

`VK_DEFINE_HANDLE` defines a dispatchable handle type.

    #define VK_DEFINE_HANDLE(object) typedef struct object##_T* object;

- `object` is the name of the resulting C type.

The only dispatchable handle types are those related to device and instance management, such as VkDevice.

`VK_DEFINE_NON_DISPATCHABLE_HANDLE` defines a non-dispatchable handle type.

    #if !defined(VK_DEFINE_NON_DISPATCHABLE_HANDLE)
    #if defined(__LP64__) || defined(_WIN64) || (defined(__x86_64__) && !defined(__ILP32__) ) || defined(_M_X64) || defined(__ia64) || defined (_M_IA64) || defined(__aarch64__) || defined(__powerpc64__)
            #define VK_DEFINE_NON_DISPATCHABLE_HANDLE(object) typedef struct object##_T *object;
    #else
            #define VK_DEFINE_NON_DISPATCHABLE_HANDLE(object) typedef uint64_t object;
    #endif
    #endif

- `object` is the name of the resulting C type.

Most Vulkan handle types, such as VkBuffer, are non-dispatchable.

| Note The `vulkan_core.h` header allows the `VK_DEFINE_NON_DISPATCHABLE_HANDLE` definition to be overridden by the application. If `VK_DEFINE_NON_DISPATCHABLE_HANDLE` is already defined when `vulkan_core.h` is compiled, the default definition is skipped. This allows the application to define a binary-compatible custom handle which may provide more type-safety or other features needed by the application. Applications must not define handles in a way that is not binary compatible - where binary compatibility is platform dependent.

`VK_NULL_HANDLE` is a reserved value representing a non-valid object handle. It may be passed to and returned from Vulkan commands only when specifically allowed.

    #define VK_NULL_HANDLE 0

### Window System-Specific Header Control (Informative)

To use a Vulkan extension supporting a platform-specific window system, header files for that window systems must be included at compile time, or platform-specific types must be forward-declared. The Vulkan header files cannot determine whether or not an external header is available at compile time, so platform-specific extensions are provided in separate headers from the core API and platform-independent extensions, allowing applications to decide which ones should be defined and how the external headers are included.

Extensions dependent on particular sets of platform headers, or that forward-declare platform-specific types, are declared in a header named for that platform. Before including these platform-specific Vulkan headers, applications must include both `vulkan_core.h` and any external native headers the platform extensions depend on.

As a convenience for applications that do not need the flexibility of separate platform-specific Vulkan headers, `vulkan.h` includes `vulkan_core.h`, and then conditionally includes platform-specific Vulkan headers and the external headers they depend on. Applications control which platform-specific headers are included by #defining macros before including `vulkan.h`.

The correspondence between platform-specific extensions, external headers they require, the platform-specific header which declares them, and the preprocessor macros which enable inclusion by `vulkan.h` are shown in the following table.

Table 84. Window System Extensions and Headers
Extension Name | Window System Name | Platform-specific Header | Required External Headers | Controlling `vulkan.h` Macro
--- | --- | --- | --- | ---
`VK_KHR_android_surface` | Android | `vulkan_android.h` | None | `VK_USE_PLATFORM_ANDROID_KHR`
`VK_KHR_wayland_surface` | Wayland | `vulkan_wayland.h` | `<wayland-client.h>` | `VK_USE_PLATFORM_WAYLAND_KHR`
`VK_KHR_win32_surface`, `VK_KHR_external_memory_win32`, `VK_KHR_win32_keyed_mutex`, `VK_KHR_external_semaphore_win32`, `VK_KHR_external_fence_win32`, `VK_NV_external_memory_win32`, `VK_NV_win32_keyed_mutex` | Microsoft Windows | `vulkan_win32.h` | `<windows.h>` | `VK_USE_PLATFORM_WIN32_KHR`
`VK_KHR_xcb_surface` | X11 Xcb | `vulkan_xcb.h` | `<xcb/xcb.h>` | `VK_USE_PLATFORM_XCB_KHR`
`VK_KHR_xlib_surface` | X11 Xlib | `vulkan_xlib.h` | `<X11/Xlib.h>` | `VK_USE_PLATFORM_XLIB_KHR`
`VK_EXT_acquire_xlib_display` | X11 XRAndR | `vulkan_xlib_xrandr.h` | `<X11/Xlib.h>`, `<X11/extensions/Xrandr.h>` | `VK_USE_PLATFORM_XLIB_XRANDR_EXT`
`VK_GGP_stream_descriptor_surface`, `VK_GGP_frame_token` | Google Games Platform | `vulkan_ggp.h` | <ggp_c/vulkan_types.h> | `VK_USE_PLATFORM_GGP`
`VK_MVK_ios_surface` | iOS | `vulkan_ios.h` | None | `VK_USE_PLATFORM_IOS_MVK`
`VK_MVK_macos_surface` | macOS | `vulkan_macos.h` | None | `VK_USE_PLATFORM_MACOS_MVK`
`VK_NN_vi_surface` | VI | `vulkan_vi.h` | None | `VK_USE_PLATFORM_VI_NN`
`VK_FUCHSIA_imagepipe_surface` | Fuchsia | `vulkan_fuchsia.h` | `<zircon/types.h>` | `VK_USE_PLATFORM_FUCHSIA`
`VK_EXT_metal_surface` | Metal on CoreAnimation | `vulkan_metal.h` | None | `VK_USE_PLATFORM_METAL_EXT`

| Note This section describes the purpose of the headers independently of the specific underlying functionality of the window system extensions themselves. Each extension name will only link to a description of that extension when viewing a specification built with that extension included.

### Provisional Extension Header Control (Informative)

Provisional extensions should not be used in production applications. The functionality defined by such extensions may change in ways that break backwards compatibility between revisions, and before final release of a non-provisional version of that extension.

Provisional extensions are defined in a separate provisional header, `vulkan_beta.h`, allowing applications to decide whether or not to include them. The mechanism is similar to window system-specific headers: before including `vulkan_beta.h`, applications must include `vulkan_core.h`.

| Note Sometimes a provisional extension will include a subset of its interfaces in `vulkan_core.h`. This may occur if the provisional extension is promoted from an existing vendor or EXT extension and some of the existing interfaces are defined as aliases of the provisional extension interfaces. All other interfaces of that provisional extension which are not aliased will be included in `vulkan_beta.h`.

As a convenience for applications, `vulkan.h` conditionally includes `vulkan_beta.h`. Applications can control inclusion of `vulkan_beta.h` by #defining the macro `VK_ENABLE_BETA_EXTENSIONS` before including `vulkan.h`.

| Note This section describes the purpose of the provisional header independently of the specific provisional extensions which are contained in that header at any given time. The extension appendices for provisional extensions note their provisional status, and link back to this section for more information. Provisional extensions are intended to provide early access for bleeding-edge developers, with the understanding that extension interfaces may change in response to developer feedback. Provisional extensions are very likely to eventually be updated and released as non-provisional extensions, but there is no guarantee this will happen, or how long it will take if it does happen.

## Appendix G: Invariance

The Vulkan specification is not pixel exact. It therefore does not guarantee an exact match between images produced by different Vulkan implementations. However, the specification does specify exact matches, in some cases, for images produced by the same implementation. The purpose of this appendix is to identify and provide justification for those cases that require exact matches.

### Repeatability

The obvious and most fundamental case is repeated issuance of a series of Vulkan commands. For any given Vulkan and framebuffer state vector, and for any Vulkan command, the resulting Vulkan and framebuffer state must be identical whenever the command is executed on that initial Vulkan and framebuffer state. This repeatability requirement does not apply when using shaders containing side effects (image and buffer variable stores and atomic operations), because these memory operations are not guaranteed to be processed in a defined order.

The repeatability requirement does not apply for rendering done using a graphics pipeline that uses `VK_RASTERIZATION_ORDER_RELAXED_AMD`.

One purpose of repeatability is avoidance of visual artifacts when a double-buffered scene is redrawn. If rendering is not repeatable, swapping between two buffers rendered with the same command sequence may result in visible changes in the image. Such false motion is distracting to the viewer. Another reason for repeatability is testability.

Repeatability, while important, is a weak requirement. Given only repeatability as a requirement, two scenes rendered with one (small) polygon changed in position might differ at every pixel. Such a difference, while within the law of repeatability, is certainly not within its spirit. Additional invariance rules are desirable to ensure useful operation.

### Multi-pass Algorithms

Invariance is necessary for a whole set of useful multi-pass algorithms. Such algorithms render multiple times, each time with a different Vulkan mode vector, to eventually produce a result in the framebuffer. Examples of these algorithms include:

- “Erasing” a primitive from the framebuffer by redrawing it, either in a different color or using the XOR logical operation.

- Using stencil operations to compute capping planes.

### Invariance Rules

For a given Vulkan device:

Rule 1 For any given Vulkan and framebuffer state vector, and for any given Vulkan command, the resulting Vulkan and framebuffer state must be identical each time the command is executed on that initial Vulkan and framebuffer state.

Rule 2 Changes to the following state values have no side effects (the use of any other state value is not affected by the change):

Required:

- Color and depth/stencil attachment contents

- Scissor parameters (other than enable)

- Write masks (color, depth, stencil)

- Clear values (color, depth, stencil)

Strongly suggested:

- Stencil parameters (other than enable)

- Depth test parameters (other than enable)

- Blend parameters (other than enable)

- Logical operation parameters (other than enable)

Corollary 1 Fragment generation is invariant with respect to the state values listed in Rule 2.

Rule 3 The arithmetic of each per-fragment operation is invariant except with respect to parameters that directly control it.

Corollary 2 Images rendered into different color attachments of the same framebuffer, either simultaneously or separately using the same command sequence, are pixel identical.

Rule 4 Identical pipelines will produce the same result when run multiple times with the same input. The wording “Identical pipelines” means VkPipeline objects that have been created with identical SPIR-V binaries and identical state, which are then used by commands executed using the same Vulkan state vector. Invariance is relaxed for shaders with side effects, such as performing stores or atomics.

Rule 5 All fragment shaders that either conditionally or unconditionally assign `FragCoord.z` to `FragDepth` are depth-invariant with respect to each other, for those fragments where the assignment to `FragDepth` actually is done.

If a sequence of Vulkan commands specifies primitives to be rendered with shaders containing side effects (image and buffer variable stores and atomic operations), invariance rules are relaxed. In particular, rule 1, corollary 2, and rule 4 do not apply in the presence of shader side effects.

The following weaker versions of rules 1 and 4 apply to Vulkan commands involving shader side effects:

Rule 6 For any given Vulkan and framebuffer state vector, and for any given Vulkan command, the contents of any framebuffer state not directly or indirectly affected by results of shader image or buffer variable stores or atomic operations must be identical each time the command is executed on that initial Vulkan and framebuffer state.

Rule 7 Identical pipelines will produce the same result when run multiple times with the same input as long as:

- shader invocations do not use image atomic operations;

- no framebuffer memory is written to more than once by image stores, unless all such stores write the same value; and

- no shader invocation, or other operation performed to process the sequence of commands, reads memory written to by an image store.

| Note The OpenGL spec has the following invariance rule: Consider a primitive p' obtained by translating a primitive p through an offset (x, y) in window coordinates, where x and y are integers. As long as neither p' nor p is clipped, it must be the case that each fragment f' produced from p' is identical to a corresponding fragment f from p except that the center of f' is offset by (x, y) from the center of f. This rule does not apply to Vulkan and is an intentional difference from OpenGL.

When any sequence of Vulkan commands triggers shader invocations that perform image stores or atomic operations, and subsequent Vulkan commands read the memory written by those shader invocations, these operations must be explicitly synchronized.

### Tessellation Invariance

When using a pipeline containing tessellation evaluation shaders, the fixed-function tessellation primitive generator consumes the input patch specified by an application and emits a new set of primitives. The following invariance rules are intended to provide repeatability guarantees. Additionally, they are intended to allow an application with a carefully crafted tessellation evaluation shader to ensure that the sets of triangles generated for two adjacent patches have identical vertices along shared patch edges, avoiding “cracks” caused by minor differences in the positions of vertices along shared edges.

Rule 1 When processing two patches with identical outer and inner tessellation levels, the tessellation primitive generator will emit an identical set of point, line, or triangle primitives as long as the pipeline used to process the patch primitives has tessellation evaluation shaders specifying the same tessellation mode, spacing, vertex order, and point mode decorations. Two sets of primitives are considered identical if and only if they contain the same number and type of primitives and the generated tessellation coordinates for the vertex numbered m of the primitive numbered n are identical for all values of m and n.

Rule 2 The set of vertices generated along the outer edge of the subdivided primitive in triangle and quad tessellation, and the tessellation coordinates of each, depends only on the corresponding outer tessellation level and the spacing decorations in the tessellation shaders of the pipeline.

Rule 3 The set of vertices generated when subdividing any outer primitive edge is always symmetric. For triangle tessellation, if the subdivision generates a vertex with tessellation coordinates of the form (0, x, 1-x), (x, 0, 1-x), or (x, 1-x, 0), it will also generate a vertex with coordinates of exactly (0, 1-x, x), (1-x, 0, x), or (1-x, x, 0), respectively. For quad tessellation, if the subdivision generates a vertex with coordinates of (x, 0) or (0, x), it will also generate a vertex with coordinates of exactly (1-x, 0) or (0, 1-x), respectively. For isoline tessellation, if it generates vertices at (0, x) and (1, x) where x is not zero, it will also generate vertices at exactly (0, 1-x) and (1, 1-x), respectively.

Rule 4 The set of vertices generated when subdividing outer edges in triangular and quad tessellation must be independent of the specific edge subdivided, given identical outer tessellation levels and spacing. For example, if vertices at (x, 1 - x, 0) and (1-x, x, 0) are generated when subdividing the w = 0 edge in triangular tessellation, vertices must be generated at (x, 0, 1-x) and (1-x, 0, x) when subdividing an otherwise identical v = 0 edge. For quad tessellation, if vertices at (x, 0) and (1-x, 0) are generated when subdividing the v = 0 edge, vertices must be generated at (0, x) and (0, 1-x) when subdividing an otherwise identical u = 0 edge.

Rule 5 When processing two patches that are identical in all respects enumerated in rule 1 except for vertex order, the set of triangles generated for triangle and quad tessellation must be identical except for vertex and triangle order. For each triangle n1 produced by processing the first patch, there must be a triangle n2 produced when processing the second patch each of whose vertices has the same tessellation coordinates as one of the vertices in n1.

Rule 6 When processing two patches that are identical in all respects enumerated in rule 1 other than matching outer tessellation levels and/or vertex order, the set of interior triangles generated for triangle and quad tessellation must be identical in all respects except for vertex and triangle order. For each interior triangle n1 produced by processing the first patch, there must be a triangle n2 produced when processing the second patch each of whose vertices has the same tessellation coordinates as one of the vertices in n1. A triangle produced by the tessellator is considered an interior triangle if none of its vertices lie on an outer edge of the subdivided primitive.

Rule 7 For quad and triangle tessellation, the set of triangles connecting an inner and outer edge depends only on the inner and outer tessellation levels corresponding to that edge and the spacing decorations.

Rule 8 The value of all defined components of `TessCoord` will be in the range [0, 1]. Additionally, for any defined component x of `TessCoord`, the results of computing 1.0-x in a tessellation evaluation shader will be exact. If any floating-point values in the range [0, 1] fail to satisfy this property, such values must not be used as tessellation coordinate components.

## Glossary

The terms defined in this section are used consistently throughout this Specification and may be used with or without capitalization.

Accessible (Descriptor Binding)

  A descriptor binding is accessible to a shader stage if that stage is included in the `stageFlags` of the descriptor binding. Descriptors using that binding can only be used by stages in which they are accessible.

Acquire Operation (Resource)

  An operation that acquires ownership of an image subresource or buffer range.

Active (Transform Feedback)

  Transform feedback is made active after vkCmdBeginTransformFeedbackEXT executes and remains active until vkCmdEndTransformFeedbackEXT executes. While transform feedback is active, data written to variables in the output interface of the last vertex processing stage of the graphics pipeline are captured to the bound transform feedback buffers if those variables are decorated for transform feedback.

Adjacent Vertex

  A vertex in an adjacency primitive topology that is not part of a given primitive, but is accessible in geometry shaders.

Active Object (Ray Tracing)

  A primitive or instance in a ray tracing acceleration structure which has a corresponding ID, and is not inactive (meaning that it is visible to rays).

Advanced Blend Operation

  Blending performed using one of the blend operation enums introduced by the `VK_EXT_blend_operation_advanced` extension. See Advanced Blending Operations.

Alias (API type/command)

  An identical definition of another API type/command with the same behavior but a different name.

Aliased Range (Memory)

  A range of a device memory allocation that is bound to multiple resources simultaneously.

Allocation Scope

  An association of a host memory allocation to a parent object or command, where the allocation’s lifetime ends before or at the same time as the parent object is freed or destroyed, or during the parent command.

Aspect (Image)

  An image may contain multiple kinds, or aspects, of data for each pixel, where each aspect is used in a particular way by the pipeline and may be stored differently or separately from other aspects. For example, the color components of an image format make up the color aspect of the image, and may be used as a framebuffer color attachment. Some operations, like depth testing, operate only on specific aspects of an image. Others operations, like image/buffer copies, only operate on one aspect at a time.

Attachment (Render Pass)

  A zero-based integer index name used in render pass creation to refer to a framebuffer attachment that is accessed by one or more subpasses. The index also refers to an attachment description which includes information about the properties of the image view that will later be attached.

Availability Operation

  An operation that causes the values generated by specified memory write accesses to become available for future access.

Available

  A state of values written to memory that allows them to be made visible.

Axis-aligned Bounding Box

  A box bounding a region in space defined by extents along each axis and thus representing a box where each edge is aligned to one of the major axes.

Back-Facing

  See Facingness.

Batch

  A single structure submitted to a queue as part of a queue submission command, describing a set of queue operations to execute.

Backwards Compatibility

  A given version of the API is backwards compatible with an earlier version if an application, relying only on valid behavior and functionality defined by the earlier specification, is able to correctly run against each version without any modification. This assumes no active attempt by that application to not run when it detects a different version.

Binary Semaphore

  A semaphore with a boolean payload indicating whether the semaphore is signaled or unsignaled. Represented by a VkSemaphore object created with a semaphore type of `VK_SEMAPHORE_TYPE_BINARY` .

Full Compatibility

  A given version of the API is fully compatible with another version if an application, relying only on valid behavior and functionality defined by either of those specifications, is able to correctly run against each version without any modification. This assumes no active attempt by that application to not run when it detects a different version.

Binding (Memory)

  An association established between a range of a resource object and a range of a memory object. These associations determine the memory locations affected by operations performed on elements of a resource object. Memory bindings are established using the vkBindBufferMemory command for non-sparse buffer objects, using the vkBindImageMemory command for non-sparse image objects, and using the vkQueueBindSparse command for sparse resources.

Blend Constant

  Four floating point (RGBA) values used as an input to blending.

Blending

  Arithmetic operations between a fragment color value and a value in a color attachment that produce a final color value to be written to the attachment.

Buffer

  A resource that represents a linear array of data in device memory. Represented by a VkBuffer object.

Buffer Device Address

  A 64-bit value used in a shader to access buffer memory through the `PhysicalStorageBuffer` storage class.

Buffer View

  An object that represents a range of a specific buffer, and state that controls how the contents are interpreted. Represented by a VkBufferView object.

Built-In Variable

  A variable decorated in a shader, where the decoration makes the variable take values provided by the execution environment or values that are generated by fixed-function pipeline stages.

Built-In Interface Block

  A block defined in a shader that contains only variables decorated with built-in decorations, and is used to match against other shader stages.

Clip Coordinates

  The homogeneous coordinate space that vertex positions (`Position` decoration) are written in by vertex processing stages.

Clip Distance

  A built-in output from vertex processing stages that defines a clip half-space against which the primitive is clipped.

Clip Volume

  The intersection of the view volume with all clip half-spaces.

Color Attachment

  A subpass attachment point, or image view, that is the target of fragment color outputs and blending.

Color Fragment

  A unique color value within a pixel of a multisampled color image. The fragment mask will contain indices to the color fragment.

Color Renderable Format

  A VkFormat where `VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT` is set in one of the following, depending on the image’s tiling:

  - VkImageFormatProperties::`linearTilingFeatures`

  - VkImageFormatProperties::`optimalTilingFeatures`

  - VkDrmFormatModifierPropertiesEXT::`drmFormatModifierTilingFeatures`

Color Sample Mask

  A bitfield associated with a fragment, with one bit for each sample in the color attachment(s). Samples are considered to be covered based on the result of the Coverage Reduction stage. Uncovered samples do not write to color attachments.

Combined Image Sampler

  A descriptor type that includes both a sampled image and a sampler.

Command Buffer

  An object that records commands to be submitted to a queue. Represented by a VkCommandBuffer object.

Command Pool

  An object that command buffer memory is allocated from, and that owns that memory. Command pools aid multithreaded performance by enabling different threads to use different allocators, without internal synchronization on each use. Represented by a VkCommandPool object.

Compatible Allocator

  When allocators are compatible, allocations from each allocator can be freed by the other allocator.

Compatible Image Formats

  When formats are compatible, images created with one of the formats can have image views created from it using any of the compatible formats. Also see Size-Compatible Image Formats.

Compatible Queues

  Queues within a queue family. Compatible queues have identical properties.

Complete Mipmap Chain

  The entire set of miplevels that can be provided for an image, from the largest application specified miplevel size down to the minimum miplevel size. See Image Miplevel Sizing.

Completed Operation

  A deferred operation whose corresponding command has been executed to completion. See Deferred Host Operations

Component (Format)

  A distinct part of a format. Depth, stencil, and color channels (e.g. R, G, B, A), are all separate components.

Compressed Texel Block

  An element of an image having a block-compressed format, comprising a rectangular block of texel values that are encoded as a single value in memory. Compressed texel blocks of a particular block-compressed format have a corresponding width, height, and depth that define the dimensions of these elements in units of texels, and a size in bytes of the encoding in memory.

Constant Integral Expressions

  A SPIR-V constant instruction whose type is `OpTypeInt`. See Constant Instruction in section 2.2.1 “Instructions” of the Khronos SPIR-V Specification.

Cooperative Matrix

  A SPIR-V type where the storage for and computations performed on the matrix are spread across a set of invocations such as a subgroup.

Corner-Sampled Image

  A VkImage where unnormalized texel coordinates are centered on integer values instead of half-integer values. Specified by setting the `VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV` bit on VkImageCreateInfo::`flags` at image creation.

Coverage

  A bitfield associated with a fragment, where each bit is associated to a rasterization sample. Samples are initially considered to be covered based on the result of rasterization, and then coverage can subsequently be turned on or off by other fragment operations or the fragment shader. Uncovered samples do not write to framebuffer attachments.

Cull Distance

  A built-in output from vertex processing stages that defines a cull half-space where the primitive is rejected if all vertices have a negative value for the same cull distance.

Cull Volume

  The intersection of the view volume with all cull half-spaces.

Decoration (SPIR-V)

  Auxiliary information such as built-in variables, stream numbers, invariance, interpolation type, relaxed precision, etc., added to variables or structure-type members through decorations.

Deferrable Command

  A command which allows deferred execution of host-side work. See Deferred Host Operations.

Deferrable Operation

  A single logical item of host-side work which can be deferred. Represented by the VkDeferredOperationKHR object. See Deferred Host Operations.

Deprecated (feature)

  A feature is deprecated if it is no longer recommended as the correct or best way to achieve its intended purpose.

Depth/Stencil Attachment

  A subpass attachment point, or image view, that is the target of depth and/or stencil test operations and writes.

Depth/Stencil Format

  A VkFormat that includes depth and/or stencil components.

Depth/Stencil Image (or ImageView)

  A VkImage (or VkImageView) with a depth/stencil format.

Depth/Stencil Resolve Attachment

  A subpass attachment point, or image view, that is the target of a multisample resolve operation from the corresponding depth/stencil attachment at the end of the subpass.

Derivative Group

  A set of fragment or compute shader invocations that cooperate to compute derivatives, including implicit derivatives for sampled image operations.

Descriptor

  Information about a resource or resource view written into a descriptor set that is used to access the resource or view from a shader.

Descriptor Binding

  An entry in a descriptor set layout corresponding to zero or more descriptors of a single descriptor type in a set. Defined by a VkDescriptorSetLayoutBinding structure.

Descriptor Pool

  An object that descriptor sets are allocated from, and that owns the storage of those descriptor sets. Descriptor pools aid multithreaded performance by enabling different threads to use different allocators, without internal synchronization on each use. Represented by a VkDescriptorPool object.

Descriptor Set

  An object that resource descriptors are written into via the API, and that can be bound to a command buffer such that the descriptors contained within it can be accessed from shaders. Represented by a VkDescriptorSet object.

Descriptor Set Layout

  An object that defines the set of resources (types and counts) and their relative arrangement (in the binding namespace) within a descriptor set. Used when allocating descriptor sets and when creating pipeline layouts. Represented by a VkDescriptorSetLayout object.

Device

  The processor(s) and execution environment that perform tasks requested by the application via the Vulkan API.

Device Group

  A set of physical devices that support accessing each other’s memory and recording a single command buffer that can be executed on all the physical devices.

Device Index

  A zero-based integer that identifies one physical device from a logical device. A device index is valid if it is less than the number of physical devices in the logical device.

Device Mask

  A bitmask where each bit represents one device index. A device mask value is valid if every bit that is set in the mask is at a bit position that is less than the number of physical devices in the logical device.

Device Memory

  Memory accessible to the device. Represented by a VkDeviceMemory object.

Device-Level Command

  Any command that is dispatched from a logical device, or from a child object of a logical device.

Device-Level Functionality

  All device-level commands and objects, and their structures, enumerated types, and enumerants.

Device-Level Object

  Logical device objects and their child objects. For example, VkDevice, VkQueue, and VkCommandBuffer objects are device-level objects.

Device-Local Memory

  Memory that is connected to the device, and may be more performant for device access than host-local memory.

Direct Drawing Commands

  Drawing commands that take all their parameters as direct arguments to the command (and not sourced via structures in buffer memory as the indirect drawing commands). Includes vkCmdDrawMeshTasksNV, vkCmdDraw, and vkCmdDrawIndexed.

Disjoint

  Disjoint planes are image planes to which memory is bound independently.
  A disjoint image consists of multiple disjoint planes, and is created with the `VK_IMAGE_CREATE_DISJOINT_BIT` bit set.

Dispatchable Handle

  A handle of a pointer handle type which may be used by layers as part of intercepting API commands. The first argument to each Vulkan command is a dispatchable handle type.

Dispatching Commands

  Commands that provoke work using a compute pipeline. Includes vkCmdDispatch and vkCmdDispatchIndirect.

Drawing Commands

  Commands that provoke work using a graphics pipeline. Includes vkCmdDraw, vkCmdDrawIndexed, vkCmdDrawIndirectCount, vkCmdDrawIndexedIndirectCount, vkCmdDrawIndirectCountKHR, vkCmdDrawIndexedIndirectCountKHR, vkCmdDrawIndirectCountAMD, vkCmdDrawIndexedIndirectCountAMD, vkCmdDrawMeshTasksNV, vkCmdDrawMeshTasksIndirectNV, vkCmdDrawMeshTasksIndirectCountNV, vkCmdDrawIndirect, and vkCmdDrawIndexedIndirect.

Duration (Command)

  The duration of a Vulkan command refers to the interval between calling the command and its return to the caller.

Dynamic Storage Buffer

  A storage buffer whose offset is specified each time the storage buffer is bound to a command buffer via a descriptor set.

Dynamic Uniform Buffer

  A uniform buffer whose offset is specified each time the uniform buffer is bound to a command buffer via a descriptor set.

Dynamically Uniform

  See Dynamically Uniform in section 2.2 “Terms” of the Khronos SPIR-V Specification.

Element

  Arrays are composed of multiple elements, where each element exists at a unique index within that array. Used primarily to describe data passed to or returned from the Vulkan API.

Explicitly-Enabled Layer

  A layer enabled by the application by adding it to the enabled layer list in vkCreateInstance or vkCreateDevice.

Event

  A synchronization primitive that is signaled when execution of previous commands complete through a specified set of pipeline stages. Events can be waited on by the device and polled by the host. Represented by a VkEvent object.

Executable State (Command Buffer)

  A command buffer that has ended recording commands and can be executed. See also Initial State and Recording State.

Execution Dependency

  A dependency that guarantees that certain pipeline stages’ work for a first set of commands has completed execution before certain pipeline stages’ work for a second set of commands begins execution. This is accomplished via pipeline barriers, subpass dependencies, events, or implicit ordering operations.

Execution Dependency Chain

  A sequence of execution dependencies that transitively act as a single execution dependency.

Explicit chroma reconstruction

  An implementation of sampler Y′CBCR conversion which reconstructs reduced-resolution chroma samples to luma resolution and then separately performs texture sample interpolation. This is distinct from an implicit implementation, which incorporates chroma sample reconstruction into texture sample interpolation.

Extension Scope

  The set of objects and commands that can be affected by an extension. Extensions are either device scope or instance scope.

External Handle

  A resource handle which has meaning outside of a specific Vulkan device or its parent instance. External handles may be used to share resources between multiple Vulkan devices in different instances, or between Vulkan and other APIs. Some external handle types correspond to platform-defined handles, in which case the resource may outlive any particular Vulkan device or instance and may be transferred between processes, or otherwise manipulated via functionality defined by the platform for that handle type.

External synchronization

  A type of synchronization required of the application, where parameters defined to be externally synchronized must not be used simultaneously in multiple threads.

Facingness (Polygon)

  A classification of a polygon as either front-facing or back-facing, depending on the orientation (winding order) of its vertices.

Facingness (Fragment)

  A fragment is either front-facing or back-facing, depending on the primitive it was generated from. If the primitive was a polygon (regardless of polygon mode), the fragment inherits the facingness of the polygon. All other fragments are front-facing.

Fence

  A synchronization primitive that is signaled when a set of batches or sparse binding operations complete execution on a queue. Fences can be waited on by the host. Represented by a VkFence object.

Flat Shading

  A property of a vertex attribute that causes the value from a single vertex (the provoking vertex) to be used for all vertices in a primitive, and for interpolation of that attribute to return that single value unaltered.

Fragment

  A rectangular framebuffer region with associated data produced by rasterization and processed by fragment operations including the fragment shader.

Fragment Area

  The width and height, in pixels, of a fragment.

Fragment Density

  The ratio of fragments per framebuffer area in the x and y direction.

Fragment Density Texel Size

  The (w,h) framebuffer region in pixels that each texel in a fragment density map applies to.

Fragment Input Attachment Interface

  Variables with `UniformConstant` storage class and a decoration of `InputAttachmentIndex` that are statically used by a fragment shader’s entry point, which receive values from input attachments.

Fragment Mask

  A lookup table that associates color samples with color fragment values.

Fragment Output Interface

  A fragment shader entry point’s variables with `Output` storage class, which output to color and/or depth/stencil attachments.

Framebuffer

  A collection of image views and a set of dimensions that, in conjunction with a render pass, define the inputs and outputs used by drawing commands. Represented by a VkFramebuffer object.

Framebuffer Attachment

  One of the image views used in a framebuffer.

Framebuffer Coordinates

  A coordinate system in which adjacent pixels’ coordinates differ by 1 in x and/or y, with (0,0) in the upper left corner and pixel centers at half-integers.

Framebuffer-Space

  Operating with respect to framebuffer coordinates.

Framebuffer-Local

  A framebuffer-local dependency guarantees that only for a single framebuffer region, the first set of operations happens-before the second set of operations.

Framebuffer-Global

  A framebuffer-global dependency guarantees that for all framebuffer regions, the first set of operations happens-before the second set of operations.

Framebuffer Region

  A framebuffer region is a set of sample (x, y, layer, sample) coordinates that is a subset of the entire framebuffer.

Front-Facing

  See Facingness.

Global Workgroup

  A collection of local workgroups dispatched by a single dispatch command. In addition to the compute dispatch, a single mesh task draw command can also generate such a collection.

Handle

  An opaque integer or pointer value used to refer to a Vulkan object. Each object type has a unique handle type.

Happen-after, happens-after

  A transitive, irreflexive and antisymmetric ordering relation between operations. An execution dependency with a source of A and a destination of B enforces that B happens-after A. The inverse relation of happens-before.

Happen-before, happens-before

  A transitive, irreflexive and antisymmetric ordering relation between operations. An execution dependency with a source of A and a destination of B enforces that A happens-before B. The inverse relation of happens-after.

Helper Invocation

  A fragment shader invocation that is created solely for the purposes of evaluating derivatives for use in non-helper fragment shader invocations, and which does not have side effects.

Host

  The processor(s) and execution environment that the application runs on, and that the Vulkan API is exposed on.

Host Mapped Device Memory

  Device memory that is mapped for host access using vkMapMemory.

Host Mapped Foreign Memory

  Memory owned by a foreign device that is mapped for host access.

Host Memory

  Memory not accessible to the device, used to store implementation data structures.

Host-Accessible Subresource

  A buffer, or a linear image subresource in either the `VK_IMAGE_LAYOUT_PREINITIALIZED` or `VK_IMAGE_LAYOUT_GENERAL` layout. Host-accessible subresources have a well-defined addressing scheme which can be used by the host.

Host-Local Memory

  Memory that is not local to the device, and may be less performant for device access than device-local memory.

Host-Visible Memory

  Device memory that can be mapped on the host and can be read and written by the host.

Identically Defined Objects

  Objects of the same type where all arguments to their creation or allocation functions, with the exception of `pAllocator`, are

  1. Vulkan handles which refer to the same object or

  2. identical scalar or enumeration values or

  3. Host pointers which point to an array of values or structures which also satisfy these three constraints.

Image

  A resource that represents a multi-dimensional formatted interpretation of device memory. Represented by a VkImage object.

Image Subresource

  A specific mipmap level and layer of an image.

Image Subresource Range

  A set of image subresources that are contiguous mipmap levels and layers.

Image View

  An object that represents an image subresource range of a specific image, and state that controls how the contents are interpreted. Represented by a VkImageView object.

Immutable Sampler

  A sampler descriptor provided at descriptor set layout creation time, and that is used for that binding in all descriptor sets allocated from the layout, and cannot be changed.

Implicit chroma reconstruction

  An implementation of sampler Y′CBCR conversion which reconstructs the reduced-resolution chroma samples directly at the sample point, as part of the normal texture sampling operation. This is distinct from an explicit chroma reconstruction implementation, which reconstructs the reduced-resolution chroma samples to the resolution of the luma samples, then filters the result as part of texture sample interpolation.

Implicitly-Enabled Layer

  A layer enabled by a loader-defined mechanism outside the Vulkan API, rather than explicitly by the application during instance or device creation.

Inactive Object (Ray Tracing)

  A primitive or instance in a ray tracing acceleration structure which has a corresponding ID, but which will never report an intersection with any ray.

Index Buffer

  A buffer bound via vkCmdBindIndexBuffer which is the source of index values used to fetch vertex attributes for a vkCmdDrawIndexed or vkCmdDrawIndexedIndirect command.

Indexed Drawing Commands

  Drawing commands which use an index buffer as the source of index values used to fetch vertex attributes for a drawing command. Includes vkCmdDrawIndexed, vkCmdDrawIndexedIndirectCount, vkCmdDrawIndexedIndirectCountKHR, vkCmdDrawIndexedIndirectCountAMD, and vkCmdDrawIndexedIndirect.

Indirect Commands

  Drawing or dispatching commands that source some of their parameters from structures in buffer memory. Includes vkCmdDrawIndirect, vkCmdDrawIndexedIndirect, vkCmdDrawIndirectCount, vkCmdDrawIndexedIndirectCount, vkCmdDrawIndirectCountKHR, vkCmdDrawIndexedIndirectCountKHR, vkCmdDrawIndirectCountAMD, vkCmdDrawIndexedIndirectCountAMD, vkCmdDrawMeshTasksIndirectNV, vkCmdDrawMeshTasksIndirectCountNV, and vkCmdDispatchIndirect.

Indirect Commands Layout

  A definition of a sequence of commands, that are generated on the device via vkCmdPreprocessGeneratedCommandsNV and vkCmdExecuteGeneratedCommandsNV. Each sequence is comprised of multiple VkIndirectCommandsTokenTypeNV, which represent a subset of traditional command buffer commands. Represented as VkIndirectCommandsLayoutNV.

Indirect Drawing Commands

  Drawing commands that source some of their parameters from structures in buffer memory. Includes vkCmdDrawIndirect, vkCmdDrawIndirectCount, vkCmdDrawIndexedIndirectCount, vkCmdDrawIndirectCountKHR, vkCmdDrawIndexedIndirectCountKHR, vkCmdDrawIndirectCountAMD, vkCmdDrawIndexedIndirectCountAMD, vkCmdDrawMeshTasksIndirectNV, vkCmdDrawMeshTasksIndirectCountNV, and vkCmdDrawIndexedIndirect.

Initial State (Command Buffer)

  A command buffer that has not begun recording commands. See also Recorded State and Executable State.

Inline Uniform Block

  A descriptor type that represents uniform data stored directly in descriptor sets, and supports read-only access in a shader.

Input Attachment

  A descriptor type that represents an image view, and supports unfiltered read-only access in a shader, only at the fragment’s location in the view.

Instance

  The top-level Vulkan object, which represents the application’s connection to the implementation. Represented by a VkInstance object.

Instance-Level Command

  Any command that is dispatched from an instance, or from a child object of an instance, except for physical devices and their children.

Instance-Level Functionality

  All instance-level commands and objects, and their structures, enumerated types, and enumerants.

Instance-Level Object

  High-level Vulkan objects, which are not physical devices, nor children of physical devices. For example, VkInstance is an instance-level object.

Instance (Memory)

  In a logical device representing more than one physical device, some device memory allocations have the requested amount of memory allocated multiple times, once for each physical device in a device mask. Each such replicated allocation is an instance of the device memory.

Instance (Resource)

  In a logical device representing more than one physical device, buffer and image resources exist on all physical devices but can be bound to memory differently on each. Each such replicated resource is an instance of the resource.

Internal Synchronization

  A type of synchronization required of the implementation, where parameters not defined to be externally synchronized may require internal mutexing to avoid multithreaded race conditions.

Invocation (Shader)

  A single execution of an entry point in a SPIR-V module. For example, a single vertex’s execution of a vertex shader or a single fragment’s execution of a fragment shader.

Invocation Group

  A set of shader invocations that are executed in parallel and that must execute the same control flow path in order for control flow to be considered dynamically uniform.

Invocation Repack Instruction

  A ray tracing shader call instruction where the implementation may change the set of invocations that are executing.

Join (Deferred Host Operations)

  The act of instructing a thread to participate in the execution of a deferred operation. See Deferred Host Operations.

Linear Resource

  A resource is linear if it is one of the following:

  - a VkBuffer

  - a VkImage created with `VK_IMAGE_TILING_LINEAR`

  - a VkImage created with `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT` and whose Linux DRM format modifier is `DRM_FORMAT_MOD_LINEAR`

    A resource is non-linear if it is one of the following:

  - a VkImage created with `VK_IMAGE_TILING_OPTIMAL`

  - a VkImage created with `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT` and whose Linux DRM format modifier is not `DRM_FORMAT_MOD_LINEAR`

Linux DRM Format Modifier

  A 64-bit, vendor-prefixed, semi-opaque unsigned integer describing vendor-specific details of an image’s memory layout. In Linux graphics APIs, modifiers are commonly used to specify the memory layout of externally shared images. An image has a modifier if and only if it is created with `tiling` equal to `VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT`. For more details, refer to the appendix for extension `VK_EXT_image_drm_format_modifier`.

Local Workgroup

  A collection of compute shader invocations invoked by a single dispatch command, which share data via `WorkgroupLocal` variables and can synchronize with each other.

Logical Device

  An object that represents the application’s interface to the physical device. The logical device is the parent of most Vulkan objects. Represented by a VkDevice object.

Logical Operation

  Bitwise operations between a fragment color value and a value in a color attachment, that produce a final color value to be written to the attachment.

Lost Device

  A state that a logical device may be in as a result of unrecoverable implementation errors, or other exceptional conditions.

Mappable

  See Host-Visible Memory.

Memory Dependency

  A memory dependency is an execution dependency which includes availability and visibility operations such that:

  - The first set of operations happens-before the availability operation

  - The availability operation happens-before the visibility operation

  - The visibility operation happens-before the second set of operations

Memory Domain

  A memory domain is an abstract place to which memory writes are made available by availability operations and memory domain operations. The memory domains correspond to the set of agents that the write can then be made visible to. The memory domains are host, device, shader, workgroup instance (for workgroup instance there is a unique domain for each compute workgroup) and subgroup instance (for subgroup instance there is a unique domain for each subgroup).

Memory Domain Operation

  An operation that makes the writes that are available to one memory domain available to another memory domain.

Memory Heap

  A region of memory from which device memory allocations can be made.

Memory Type

  An index used to select a set of memory properties (e.g. mappable, cached) for a device memory allocation.

Mesh Shading Pipeline

  A graphics pipeline where the primitives are assembled explicitly in the shader stages. In contrast to the primitive shading pipeline where input primitives are assembled by fixed function processing.

Mesh Tasks Drawing Commands

  Drawing commands which create shader invocations organized in workgroups for drawing mesh tasks. Includes vkCmdDrawMeshTasksNV, vkCmdDrawMeshTasksIndirectNV, and vkCmdDrawMeshTasksIndirectCountNV.

Minimum Miplevel Size

  The smallest size that is permitted for a miplevel. For conventional images this is 1x1x1. For corner-sampled images, this is 2x2x2. See Image Miplevel Sizing.

Mip Tail Region

  The set of mipmap levels of a sparse residency texture that are too small to fill a sparse block, and that must all be bound to memory collectively and opaquely.

Multi-planar

  A multi-planar format (or “planar format”) is an image format consisting of more than one plane, identifiable with a `_2PLANE` or `_3PLANE` component to the format name and listed in Formats requiring sampler Y′CBCR conversion for `VK_IMAGE_ASPECT_COLOR_BIT` image views. A multi-planar image (or “planar image”) is an image of a multi-planar format.

Non-Dispatchable Handle

  A handle of an integer handle type. Handle values may not be unique, even for two objects of the same type.

Non-Indexed Drawing Commands

  Drawing commands for which the vertex attributes are sourced in linear order from the vertex input attributes for a drawing command (i.e. they do not use an index buffer). Includes vkCmdDraw, vkCmdDrawIndirectCount, vkCmdDrawIndirectCountKHR, vkCmdDrawIndirectCountAMD, and vkCmdDrawIndirect.

Normalized

  A value that is interpreted as being in the range [0,1] as a result of being implicitly divided by some other value.

Normalized Device Coordinates

  A coordinate space after perspective division is applied to clip coordinates, and before the viewport transformation converts to framebuffer coordinates.

Obsoleted (feature)

  A feature is obsolete if it can no longer be used.

Opaque Capture Address

  A 64-bit value representing the device address of a buffer or memory object that is expected to be used by trace capture/replay tools in combination with the bufferDeviceAddress feature.

Overlapped Range (Aliased Range)

  The aliased range of a device memory allocation that intersects a given image subresource of an image or range of a buffer.

Ownership (Resource)

  If an entity (e.g. a queue family) has ownership of a resource, access to that resource is well-defined for access by that entity.

Packed Format

  A format whose components are stored as a single texel block in memory, with their relative locations defined within that element.

Passthrough Geometry Shader

  A geometry shader which uses the `PassthroughNV` decoration on a variable in its input interface. Output primitives in a passthrough geometry shader always have the same topology as the input primitive and are not produced by emitting vertices.

Payload

  Importable or exportable reference to the internal data of an object in Vulkan.

Per-View

  A variable that has an array of values which are output, one for each view that is being generated. A mesh shader which uses the `PerViewNV` decoration on a variable in its output interface.

Peer Memory

  An instance of memory corresponding to a different physical device than the physical device performing the memory access, in a logical device that represents multiple physical devices.

Physical Device

  An object that represents a single device in the system. Represented by a VkPhysicalDevice object.

Physical-Device-Level Command

  Any command that is dispatched from a physical device.

Physical-Device-Level Functionality

  All physical-device-level commands and objects, and their structures, enumerated types, and enumerants.

Physical-Device-Level Object

  Physical device objects. For example, VkPhysicalDevice is a physical-device-level object.

Pipeline

  An object that controls how graphics or compute work is executed on the device. A pipeline includes one or more shaders, as well as state controlling any non-programmable stages of the pipeline. Represented by a VkPipeline object.

Pipeline Barrier

  An execution and/or memory dependency recorded as an explicit command in a command buffer, that forms a dependency between the previous and subsequent commands.

Pipeline Cache

  An object that can be used to collect and retrieve information from pipelines as they are created, and can be populated with previously retrieved information in order to accelerate pipeline creation. Represented by a VkPipelineCache object.

Pipeline Layout

  An object that defines the set of resources (via a collection of descriptor set layouts) and push constants used by pipelines that are created using the layout. Used when creating a pipeline and when binding descriptor sets and setting push constant values. Represented by a VkPipelineLayout object.

Pipeline Library

  A pipeline that cannot be directly used, instead defining a set of shaders and shader groups which will be linked into other pipelines.

Pipeline Stage

  A logically independent execution unit that performs some of the operations defined by an action command.

`pNext` Chain

  A set of structures chained together through their `pNext` members.

Planar

  See multi-planar.

Plane

  An image plane is part of the representation of an image, containing a subset of the color channels required to represent the texels in the image and with a contiguous mapping of coordinates to bound memory. Most images consist only of a single plane, but some formats spread the channels across multiple image planes. The host-accessible properties of each image plane are accessed in a linear layout using vkGetImageSubresourceLayout. If a multi-planar image is created with the `VK_IMAGE_CREATE_DISJOINT_BIT` bit set, the image is described as disjoint, and its planes are therefore are bound to memory independently.

Point Sampling (Rasterization)

  A rule that determines whether a fragment sample location is covered by a polygon primitive by testing whether the sample location is in the interior of the polygon in framebuffer-space, or on the boundary of the polygon according to the tie-breaking rules.

Presentable image

  A `VkImage` object obtained from a `VkSwapchainKHR` used to present to a `VkSurfaceKHR` object.

Preserve Attachment

  One of a list of attachments in a subpass description that is not read or written by the subpass, but that is read or written on earlier and later subpasses and whose contents must be preserved through this subpass.

Primary Command Buffer

  A command buffer that can execute secondary command buffers, and can be submitted directly to a queue.

Primitive Shading Pipeline

  A graphics pipeline where input primitives are assembled by fixed function processing. It is the counterpart to mesh shading.

Primitive Topology

  State that controls how vertices are assembled into primitives, e.g. as lists of triangles, strips of lines, etc..

Promoted (feature)

  A feature from an older extension is considered promoted if it is made available as part of a new core version or newer extension with wider support.

Protected Buffer

  A buffer to which protected device memory can be bound.

Protected-capable Device Queue

  A device queue to which protected command buffers can be submitted.

Protected Command Buffer

  A command buffer which can be submitted to a protected-capable device queue.

Protected Device Memory

  Device memory which can be visible to the device but must not be visible to the host.

Protected Image

  An image to which protected device memory can be bound.

Provisional

  A feature is released provisionally in order to get wider feedback on the functionality before it is finalized. Provisional features may change in ways that break backwards compatibility, and thus are not recommended for use in production applications.

Provoking Vertex

  The vertex in a primitive from which flat shaded attribute values are taken. This is generally the “first” vertex in the primitive, and depends on the primitive topology.

Push Constants

  A small bank of values writable via the API and accessible in shaders. Push constants allow the application to set values used in shaders without creating buffers or modifying and binding descriptor sets for each update.

Push Constant Interface

  The set of variables with `PushConstant` storage class that are statically used by a shader entry point, and which receive values from push constant commands.

Push Descriptors

  Descriptors that are written directly into a command buffer rather than into a descriptor set. Push descriptors allow the application to set descriptors used in shaders without allocating or modifying descriptor sets for each update.

Descriptor Update Template

  An object that specifies a mapping from descriptor update information in host memory to elements in a descriptor set, which helps enable more efficient descriptor set updates.

Query Pool

  An object containing a number of query entries and their associated state and results. Represented by a VkQueryPool object.

Queue

  An object that executes command buffers and sparse binding operations on a device. Represented by a VkQueue object.

Queue Family

  A set of queues that have common properties and support the same functionality, as advertised in VkQueueFamilyProperties.

Queue Operation

  A unit of work to be executed by a specific queue on a device, submitted via a queue submission command. Each queue submission command details the specific queue operations that occur as a result of calling that command. Queue operations typically include work that is specific to each command, and synchronization tasks.

Queue Submission

  Zero or more batches and an optional fence to be signaled, passed to a command for execution on a queue. See the Devices and Queues chapter for more information.

Recording State (Command Buffer)

  A command buffer that is ready to record commands. See also Initial State and Executable State.

Release Operation (Resource)

  An operation that releases ownership of an image subresource or buffer range.

Render Pass

  An object that represents a set of framebuffer attachments and phases of rendering using those attachments. Represented by a VkRenderPass object.

Render Pass Instance

  A use of a render pass in a command buffer.

Required Extensions

  Extensions that must be enabled alongside extensions dependent on them (see Extension Dependencies).

Reset (Command Buffer)

  Resetting a command buffer discards any previously recorded commands and puts a command buffer in the initial state.

Residency Code

  An integer value returned by sparse image instructions, indicating whether any sparse unbound texels were accessed.

Resolve Attachment

  A subpass attachment point, or image view, that is the target of a multisample resolve operation from the corresponding color attachment at the end of the subpass.

Retired Swapchain

  A swapchain that has been used as the `oldSwapchain` parameter to vkCreateSwapchainKHR. Images cannot be acquired from a retired swapchain, however images that were acquired (but not presented) before the swapchain was retired can be presented.

Sample Shading

  Invoking the fragment shader multiple times per fragment, with the covered samples partitioned among the invocations.

Sampled Image

  A descriptor type that represents an image view, and supports filtered (sampled) and unfiltered read-only access in a shader.

Sampler

  An object containing state that controls how sampled image data is sampled (or filtered) when accessed in a shader. Also a descriptor type describing the object. Represented by a VkSampler object.

Secondary Command Buffer

  A command buffer that can be executed by a primary command buffer, and must not be submitted directly to a queue.

Self-Dependency

  A subpass dependency from a subpass to itself, i.e. with `srcSubpass` equal to `dstSubpass`. A self-dependency is not automatically performed during a render pass instance, rather a subset of it can be performed via vkCmdPipelineBarrier during the subpass.

Semaphore

  A synchronization primitive that supports signal and wait operations, and can be used to synchronize operations within a queue or across queues. Represented by a VkSemaphore object.

Shader

  Instructions selected (via an entry point) from a shader module, which are executed in a shader stage.

Shader Call

  An instruction which may cause execution to continue in a different shader stage.

Shader Code

  A stream of instructions used to describe the operation of a shader.

Shader Group

  A set of Shader Stages that are part of a slink::VkPipeline which contains multiple of such sets. This allows the device to make use of all the shader groups from the bound pipeline independently.

Shader Module

  A collection of shader code, potentially including several functions and entry points, that is used to create shaders in pipelines. Represented by a VkShaderModule object.

Shader Stage

  A stage of the graphics or compute pipeline that executes shader code.

Shading Rate

  The ratio of the number of fragment shader invocations generated in a fully covered framebuffer region to the size (in pixels) of that region.

Shading Rate Image

  An image used to establish the shading rate for a framebuffer region, where each pixel controls the shading rate for a corresponding framebuffer region.

Shared presentable image

  A presentable image created from a swapchain with VkPresentModeKHR set to either `VK_PRESENT_MODE_SHARED_DEMAND_REFRESH_KHR` or `VK_PRESENT_MODE_SHARED_CONTINUOUS_REFRESH_KHR`.

Side Effect

  A store to memory or atomic operation on memory from a shader invocation.

Single-plane format

  A format that is not multi-planar.

Size-Compatible Image Formats

  When a compressed image format and an uncompressed image format are size-compatible, it means that the texel block size of the uncompressed format must equal the texel block size of the compressed format.

Sparse Block

  An element of a sparse resource that can be independently bound to memory. Sparse blocks of a particular sparse resource have a corresponding size in bytes that they use in the bound memory.

Sparse Image Block

  A sparse block in a sparse partially-resident image. In addition to the sparse block size in bytes, sparse image blocks have a corresponding width, height, and depth that define the dimensions of these elements in units of texels or compressed texel blocks, the latter being used in case of sparse images having a block-compressed format.

Sparse Unbound Texel

  A texel read from a region of a sparse texture that does not have memory bound to it.

Static Use

  An object in a shader is statically used by a shader entry point if any function in the entry point’s call tree contains an instruction using the object. Static use is used to constrain the set of descriptors used by a shader entry point.

Storage Buffer

  A descriptor type that represents a buffer, and supports reads, writes, and atomics in a shader.

Storage Image

  A descriptor type that represents an image view, and supports unfiltered loads, stores, and atomics in a shader.

Storage Texel Buffer

  A descriptor type that represents a buffer view, and supports unfiltered, formatted reads, writes, and atomics in a shader.

Subgroup

  A set of shader invocations that can synchronize and share data with each other efficiently. In compute shaders, the local workgroup is a superset of the subgroup.

Subgroup Mask

  A bitmask for all invocations in the current subgroup with one bit per invocation, starting with the least significant bit in the first vector component, continuing to the last bit (less than `SubgroupSize`) in the last required vector component.

Subpass

  A phase of rendering within a render pass, that reads and writes a subset of the attachments.

Subpass Dependency

  An execution and/or memory dependency between two subpasses described as part of render pass creation, and automatically performed between subpasses in a render pass instance. A subpass dependency limits the overlap of execution of the pair of subpasses, and can provide guarantees of memory coherence between accesses in the subpasses.

Subpass Description

  Lists of attachment indices for input attachments, color attachments, depth/stencil attachment, resolve attachments, depth/stencil resolve, and preserve attachments used by the subpass in a render pass.

Subset (Self-Dependency)

  A subset of a self-dependency is a pipeline barrier performed during the subpass of the self-dependency, and whose stage masks and access masks each contain a subset of the bits set in the identically named mask in the self-dependency.

Texel Block

  A single addressable element of an image with an uncompressed VkFormat, or a single compressed block of an image with a compressed VkFormat.

Texel Block Size

  The size (in bytes) used to store a texel block of a compressed or uncompressed image.

Texel Coordinate System

  One of three coordinate systems (normalized, unnormalized, integer) that define how texel coordinates are interpreted in an image or a specific mipmap level of an image.

Timeline Semaphore

  A semaphore with a monotonically increasing 64-bit unsigned integer payload indicating whether the semaphore is signaled with respect to a particular reference value. Represented by a VkSemaphore object created with a semaphore type of `VK_SEMAPHORE_TYPE_TIMELINE`.

Uniform Texel Buffer

  A descriptor type that represents a buffer view, and supports unfiltered, formatted, read-only access in a shader.

Uniform Buffer

  A descriptor type that represents a buffer, and supports read-only access in a shader.

Units in the Last Place (ULP)

  A measure of floating-point error loosely defined as the smallest representable step in a floating-point format near a given value. For the precise definition see Precision and Operation of SPIR-V instructions or Jean-Michel Muller, “On the definition of ulp(x)”, RR-5504, INRIA. Other sources may also use the term “unit of least precision”.

Unnormalized

  A value that is interpreted according to its conventional interpretation, and is not normalized.

Unprotected Buffer

  A buffer to which unprotected device memory can be bound.

Unprotected Command Buffer

  A command buffer which can be submitted to an unprotected device queue or a protected-capable device queue.

Unprotected Device Memory

  Device memory which can be visible to the device and can be visible to the host.

Unprotected Image

  An image to which unprotected device memory can be bound.

User-Defined Variable Interface

  A shader entry point’s variables with `Input` or `Output` storage class that are not built-in variables.

Vertex Input Attribute

  A graphics pipeline resource that produces input values for the vertex shader by reading data from a vertex input binding and converting it to the attribute’s format.

Vertex Stream

  A vertex stream is where the last vertex processing stage outputs vertex data, which then goes to the rasterizer, is captured to a transform feedback buffer, or both. Geometry shaders can emit primitives to multiple independent vertex streams. Each vertex emitted by the geometry shader is directed at one of the vertex streams.

Validation Cache

  An object that can be used to collect and retrieve validation results from the validation layers, and can be populated with previously retrieved results in order to accelerate the validation process. Represented by a VkValidationCacheEXT object.

Vertex Input Binding

  A graphics pipeline resource that is bound to a buffer and includes state that affects addressing calculations within that buffer.

Vertex Input Interface

  A vertex shader entry point’s variables with `Input` storage class, which receive values from vertex input attributes.

Vertex Processing Stages

  A set of shader stages that comprises the vertex shader, tessellation control shader, tessellation evaluation shader, and geometry shader stages. The task and mesh shader stages also belong to this group.

View Mask

  When multiview is enabled, a view mask is a property of a subpass controlling which views the rendering commands are broadcast to.

View Volume

  A subspace in homogeneous coordinates, corresponding to post-projection x and y values between -1 and +1, and z values between 0 and +1.

Viewport Transformation

  A transformation from normalized device coordinates to framebuffer coordinates, based on a viewport rectangle and depth range.

Visibility Operation

  An operation that causes available values to become visible to specified memory accesses.

Visible

  A state of values written to memory that allows them to be accessed by a set of operations.

## Common Abbreviations

Abbreviations and acronyms are sometimes used in the Specification and the API where they are considered clear and commonplace, and are defined here:

Src

  Source

Dst

  Destination

Min

  Minimum

Max

  Maximum

Rect

  Rectangle

Info

  Information

LOD

  Level of Detail

ID

  Identifier

UUID

  Universally Unique Identifier

Op

  Operation

R

  Red color component

G

  Green color component

B

  Blue color component

A

  Alpha color component

RTZ

  Round towards zero

RTE

  Round to nearest even

## Prefixes

Prefixes are used in the API to denote specific semantic meaning of Vulkan names, or as a label to avoid name clashes, and are explained here:

VK/Vk/vk

  Vulkan namespace
  All types, commands, enumerants and defines in this specification are prefixed with these two characters.

PFN/pfn

  Function Pointer
  Denotes that a type is a function pointer, or that a variable is of a pointer type.

p

  Pointer
  Variable is a pointer.

vkCmd

  Commands that record commands in command buffers
  These API commands do not result in immediate processing on the device. Instead, they record the requested action in a command buffer for execution when the command buffer is submitted to a queue.

s

  Structure
  Used to denote the `VK_STRUCTURE_TYPE*` member of each structure in `sType`

## Appendix H: Credits (Informative)

Vulkan 1.2 is the result of contributions from many people and companies participating in the Khronos Vulkan Working Group, as well as input from the Vulkan Advisory Panel.

Members of the Working Group, including the company that they represented at the time of their most recent contribution, are listed in the following section. Some specific contributions made by individuals are listed together with their name.

### Working Group Contributors to Vulkan

- Aaron Greig, Codeplay Software Ltd. (version 1.1)

- Aaron Hagan, AMD (version 1.1)

- Adam Jackson, Red Hat (versions 1.0, 1.1)

- Adam Śmigielski, Mobica (version 1.0)

- Aidan Fabius, Core Avionics & Industrial Inc. (version 1.2)

- Alan Baker, Google (versions 1.1, 1.2)

- Alan Ward, Google (versions 1.1, 1.2)

- Alejandro Piñeiro, Igalia (version 1.1)

- Alex Bourd, Qualcomm Technologies, Inc. (versions 1.0, 1.1)

- Alex Crabb, Caster Communications (version 1.2)

- Alex Walters, Imagination Technologies (version 1.2)

- Alexander Galazin, Arm (versions 1.0, 1.1, 1.2)

- Allen Hux, Intel (version 1.0)

- Alon Or-bach, Samsung Electronics (versions 1.0, 1.1, 1.2) (WSI technical sub-group chair)

- Anastasia Stulova, Arm (version 1.2)

- Andreas Vasilakis, Think Silicon (version 1.2)

- Andres Gomez, Igalia (version 1.1)

- Andrew Cox, Samsung Electronics (version 1.0)

- Andrew Garrard, Samsung Electronics (versions 1.0, 1.1, 1.2) (format wrangler)

- Andrew Poole, Samsung Electronics (version 1.0)

- Andrew Rafter, Samsung Electronics (version 1.0)

- Andrew Richards, Codeplay Software Ltd. (version 1.0)

- Andrew Woloszyn, Google (versions 1.0, 1.1)

- Ann Thorsnes, Khronos (version 1.2)

- Antoine Labour, Google (versions 1.0, 1.1)

- Aras Pranckevičius, Unity Technologies (version 1.0)

- Ashwin Kolhe, NVIDIA (version 1.0)

- Baldur Karlsson, Independent (versions 1.1, 1.2)

- Barthold Lichtenbelt, NVIDIA (version 1.1)

- Bas Nieuwenhuizen, Google (versions 1.1, 1.2)

- Ben Bowman, Imagination Technologies (version 1.0)

- Benj Lipchak, Unknown (version 1.0)

- Bill Hollings, Brenwill (versions 1.0, 1.1, 1.2)

- Bill Licea-Kane, Qualcomm Technologies, Inc. (versions 1.0, 1.1)

- Blaine Kohl, Khronos (version 1.2)

- Boris Zanin, Mobica (version 1.2)

- Brent E. Insko, Intel (version 1.0)

- Brian Ellis, Qualcomm Technologies, Inc. (version 1.0)

- Brian Paul, VMware (version 1.2)

- Caio Marcelo de Oliveira Filho, Intel (version 1.2)

- Cass Everitt, Oculus VR (versions 1.0, 1.1)

- Cemil Azizoglu, Canonical (version 1.0)

- Chad Versace, Google (versions 1.0, 1.1, 1.2)

- Chang-Hyo Yu, Samsung Electronics (version 1.0)

- Chia-I Wu, LunarG (version 1.0)

- Chris Frascati, Qualcomm Technologies, Inc. (version 1.0)

- Christophe Riccio, Unity Technologies (versions 1.0, 1.1)

- Cody Northrop, LunarG (version 1.0)

- Colin Riley, AMD (version 1.1)

- Cort Stratton, Google (versions 1.1, 1.2)

- Courtney Goeltzenleuchter, Google (versions 1.0, 1.1)

- Craig Davies, Huawei (version 1.2)

- Dae Kim, Imagination Technologies (version 1.1)

- Damien Leone, NVIDIA (version 1.0)

- Dan Baker, Oxide Games (versions 1.0, 1.1)

- Dan Ginsburg, Valve Software (versions 1.0, 1.1, 1.2)

- Daniel Johnston, Intel (versions 1.0, 1.1)

- Daniel Koch, NVIDIA (versions 1.0, 1.1, 1.2)

- Daniel Rakos, AMD (versions 1.0, 1.1, 1.2)

- Daniel Stone, Collabora (versions 1.1, 1.2)

- Daniel Vetter, Intel (version 1.2)

- David Airlie, Red Hat (versions 1.0, 1.1, 1.2)

- David Mao, AMD (versions 1.0, 1.2)

- David Miller, Miller & Mattson (versions 1.0, 1.1) (Vulkan reference card)

- David Neto, Google (versions 1.0, 1.1, 1.2)

- David Wilkinson, AMD (version 1.2)

- David Yu, Pixar (version 1.0)

- Dejan Mircevski, Google (version 1.1)

- Dominik Witczak, AMD (versions 1.0, 1.1)

- Donald Scorgie, Imagination Technologies (version 1.2)

- Dzmitry Malyshau, Mozilla (versions 1.1, 1.2)

- Ed Hutchins, Oculus (version 1.2)

- Emily Stearns, Khronos (version 1.2)

- Frank (LingJun) Chen, Qualcomm Technologies, Inc. (version 1.0)

- Fred Liao, Mediatek (version 1.0)

- Gabe Dagani, Freescale (version 1.0)

- Gabor Sines, AMD (version 1.2)

- Graeme Leese, Broadcom (versions 1.0, 1.1, 1.2)

- Graham Connor, Imagination Technologies (version 1.0)

- Graham Sellers, AMD (versions 1.0, 1.1)

- Greg Fischer, LunarG (version 1.1)

- Hai Nguyen, Google (version 1.2)

- Hans-Kristian Arntzen, Arm (versions 1.1, 1.2)

- Henri Verbeet, Codeweavers (version 1.2)

- Hwanyong Lee, Kyungpook National University (version 1.0)

- Iago Toral, Igalia (versions 1.1, 1.2)

- Ian Elliott, Google (versions 1.0, 1.1, 1.2)

- Ian Romanick, Intel (versions 1.0, 1.1)

- James Hughes, Oculus VR (version 1.0)

- James Jones, NVIDIA (versions 1.0, 1.1, 1.2)

- James Riordon, Khronos (version 1.2)

- Jan Hermes, Continental Corporation (versions 1.0, 1.1)

- Jan-Harald Fredriksen, Arm (versions 1.0, 1.1, 1.2)

- Jason Ekstrand, Intel (versions 1.0, 1.1, 1.2)

- Jean-François Roy, Google (versions 1.1, 1.2)

- Jeff Bolz, NVIDIA (versions 1.0, 1.1, 1.2)

- Jeff Juliano, NVIDIA (versions 1.0, 1.1, 1.2)

- Jeff Leger, Qualcomm Technologies, Inc. (version 1.1)

- Jeff Vigil, Samsung Electronics (versions 1.0, 1.1, 1.2)

- Jens Owen, Google (versions 1.0, 1.1)

- Jeremy Hayes, LunarG (version 1.0)

- Jesse Barker, Unity Technologies (versions 1.0, 1.1, 1.2)

- Jesse Hall, Google (versions 1.0, 1.1, 1.2)

- Joe Davis, Samsung Electronics (version 1.1)

- Johannes van Waveren, Oculus VR (versions 1.0, 1.1)

- John Kessenich, Google (versions 1.0, 1.1, 1.2) (SPIR-V and GLSL for Vulkan spec author)

- John McDonald, Valve Software (versions 1.0, 1.1, 1.2)

- John Zulauf, LunarG (versions 1.1, 1.2)

- Jon Ashburn, LunarG (version 1.0)

- Jon Leech, Independent (versions 1.0, 1.1, 1.2) (XML toolchain, normative language, release wrangler)

- Jonas Gustavsson, Samsung Electronics (versions 1.0, 1.1)

- Jonas Meyer, Epic Games (version 1.2)

- Jonathan Hamilton, Imagination Technologies (version 1.0)

- Jordan Justen, Intel (version 1.1)

- Jungwoo Kim, Samsung Electronics (versions 1.0, 1.1)

- Jörg Wagner, Arm (version 1.1)

- Kalle Raita, Google (version 1.1)

- Karen Ghavam, LunarG (versions 1.1, 1.2)

- Karl Schultz, LunarG (versions 1.1, 1.2)

- Kathleen Mattson, Khronos (versions 1.0, 1.1, 1.2)

- Kaye Mason, Google (version 1.2)

- Keith Packard, Valve (version 1.2)

- Kenneth Benzie, Codeplay Software Ltd. (versions 1.0, 1.1)

- Kenneth Russell, Google (version 1.1)

- Kerch Holt, NVIDIA (versions 1.0, 1.1)

- Kevin O’Neil, AMD (version 1.1)

- Kris Rose, Khronos (version 1.2)

- Kristian Kristensen, Intel (versions 1.0, 1.1)

- Krzysztof Iwanicki, Samsung Electronics (version 1.0)

- Larry Seiler, Intel (version 1.0)

- Lauri Ilola, Nokia (version 1.1)

- Lei Zhang, Google (version 1.2)

- Lenny Komow, LunarG (versions 1.1, 1.2)

- Lionel Landwerlin, Intel (versions 1.1, 1.2)

- Liz Maitral, Khronos (version 1.2)

- Lutz Latta, Lucasfilm (version 1.0)

- Maciej Jesionowski, AMD (version 1.1)

- Mais Alnasser, AMD (version 1.1)

- Marcin Rogucki, Mobica (version 1.1)

- Maria Rovatsou, Codeplay Software Ltd. (version 1.0)

- Mark Callow, Independent (versions 1.0, 1.1, 1.2)

- Mark Kilgard, NVIDIA (versions 1.1, 1.2)

- Mark Lobodzinski, LunarG (versions 1.0, 1.1, 1.2)

- Mark Young, LunarG (version 1.1)

- Markus Tavenrath, NVIDIA (version 1.1)

- Mateusz Przybylski, Intel (version 1.0)

- Mathias Heyer, NVIDIA (versions 1.0, 1.1)

- Mathias Schott, NVIDIA (versions 1.0, 1.1)

- Matt Netsch, Qualcomm Technologies, Inc. (version 1.1)

- Matthäus Chajdas, AMD (versions 1.1, 1.2)

- Maurice Ribble, Qualcomm Technologies, Inc. (versions 1.0, 1.1)

- Maxim Lukyanov, Samsung Electronics (version 1.0)

- Michael Lentine, Google (version 1.0)

- Michael O’Hara, AMD (version 1.1)

- Michael Phillip, Samsung Electronics (version 1.2)

- Michael Wong, Codeplay Software Ltd. (version 1.1)

- Michael Worcester, Imagination Technologies (versions 1.0, 1.1)

- Michal Pietrasiuk, Intel (version 1.0)

- Mika Isojarvi, Google (versions 1.0, 1.1)

- Mike Schuchardt, LunarG (versions 1.1, 1.2)

- Mike Stroyan, LunarG (version 1.0)

- Mike Weiblen, LunarG (versions 1.1, 1.2)

- Minyoung Son, Samsung Electronics (version 1.0)

- Mitch Singer, AMD (versions 1.0, 1.1, 1.2)

- Mythri Venugopal, Samsung Electronics (version 1.0)

- Naveen Leekha, Google (version 1.0)

- Neil Henning, AMD (versions 1.0, 1.1, 1.2)

- Neil Hickey, Arm (version 1.2)

- Neil Trevett, NVIDIA (versions 1.0, 1.1, 1.2)

- Nick Penwarden, Epic Games (version 1.0)

- Nicolai Hähnle, AMD (version 1.1)

- Niklas Smedberg, Unity Technologies (version 1.0)

- Norbert Nopper, Independent (versions 1.0, 1.1)

- Nuno Subtil, NVIDIA (versions 1.1, 1.2)

- Pat Brown, NVIDIA (version 1.0)

- Patrick Cozzi, Independent (version 1.1)

- Patrick Doane, Blizzard Entertainment (version 1.0)

- Peter Lohrmann, AMD (versions 1.0, 1.2)

- Petros Bantolas, Imagination Technologies (version 1.1)

- Pierre Boudier, NVIDIA (versions 1.0, 1.1, 1.2)

- Pierre-Loup Griffais, Valve Software (versions 1.0, 1.1, 1.2)

- Piers Daniell, NVIDIA (versions 1.0, 1.1, 1.2)

- Piotr Bialecki, Intel (version 1.0)

- Prabindh Sundareson, Samsung Electronics (version 1.0)

- Pyry Haulos, Google (versions 1.0, 1.1) (Vulkan conformance test subcommittee chair)

- Rajeev Rao, Qualcomm (version 1.2)

- Ralph Potter, Codeplay Software Ltd. (versions 1.1, 1.2)

- Ray Smith, Arm (versions 1.0, 1.1, 1.2)

- Richard Huddy, Samsung Electronics (version 1.2)

- Rob Barris, NVIDIA (version 1.1)

- Rob Stepinski, Transgaming (version 1.0)

- Robert Simpson, Qualcomm Technologies, Inc. (versions 1.0, 1.1)

- Rolando Caloca Olivares, Epic Games (versions 1.0, 1.1, 1.2)

- Roy Ju, Mediatek (version 1.0)

- Rufus Hamade, Imagination Technologies (version 1.0)

- Ruihao Zhang, Qualcomm Technologies, Inc. (versions 1.1, 1.2)

- Sean Ellis, Arm (version 1.0)

- Sean Harmer, KDAB Group (versions 1.0, 1.1)

- Shannon Woods, Google (versions 1.0, 1.1, 1.2)

- Slawomir Cygan, Intel (versions 1.0, 1.1)

- Slawomir Grajewski, Intel (versions 1.0, 1.1)

- Sorel Bosan, AMD (version 1.1)

- Spencer Fricke, Samsung Electronics (version 1.2)

- Stefanus Du Toit, Google (version 1.0)

- Stephen Huang, Mediatek (version 1.1)

- Steve Hill, Broadcom (versions 1.0, 1.2)

- Steve Viggers, Core Avionics & Industrial Inc. (versions 1.0, 1.2)

- Stuart Smith, Imagination Technologies (versions 1.0, 1.1, 1.2)

- Tilmann Scheller, Samsung Electronics (version 1.1)

- Tim Foley, Intel (version 1.0)

- Timo Suoranta, AMD (version 1.0)

- Timothy Lottes, AMD (versions 1.0, 1.1)

- Tobias Hector, AMD (versions 1.0, 1.1, 1.2) (validity language and toolchain)

- Tobin Ehlis, LunarG (version 1.0)

- Tom Olson, Arm (versions 1.0, 1.1, 1.2) (Working Group chair)

- Tomasz Bednarz, Independent (version 1.1)

- Tomasz Kubale, Intel (version 1.0)

- Tony Barbour, LunarG (versions 1.0, 1.1, 1.2)

- Victor Eruhimov, Unknown (version 1.1)

- Vincent Hindriksen, StreamHPC (version 1.2)

- Wayne Lister, Imagination Technologies (version 1.0)

- Wolfgang Engel, Unknown (version 1.1)

- Yanjun Zhang, VeriSilicon (versions 1.0, 1.1, 1.2)

### Other Credits

The Vulkan Advisory Panel members provided important real-world usage information and advice that helped guide design decisions.

The wider Vulkan community have provided useful feedback, questions and spec changes that have helped improve the quality of the Specification via GitHub.

Administrative support to the Working Group for Vulkan 1.1 and 1.2 was provided by Khronos staff including Angela Cheng, Ann Thorsnes, Blaine Kohl, Dominic Agoro-Ombaka, Emily Stearns, Jeff Phillips, Lisie Aartsen, and Liz Maitral; and by Alex Crabb of Caster Communications.

Administrative support for Vulkan 1.0 was provided by Andrew Riegel, Elizabeth Riegel, Glenn Fredericks, Kathleen Mattson and Michelle Clark of Gold Standard Group.

Technical support was provided by James Riordon, webmaster of Khronos.org and OpenGL.org.