// Copyright 2020-2021 The Khronos Group, Inc.
//
// SPDX-License-Identifier: CC-BY-4.0

[[acceleration-structure]]
= Acceleration Structures


[[acceleration-structure-def]]
== Acceleration Structures

_Acceleration structures_ are data structures used by the implementation to
efficiently manage scene geometry as it is <<ray-traversal, traversed during
a ray tracing query>>.
The application is responsible for managing acceleration structure objects
(see <<resources-acceleration-structures,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_.

An acceleration structure is considered to be constructed if an
<<acceleration-structure-building,acceleration structure build command>> or
<<acceleration-structure-copying,copy command>> has been executed with the
given acceleration structure as the destination.

[[fig-accelstruct]]
image::{images}/accelstruct.svg[align="center",title="Acceleration Structure",opts="{imageopts}"]

.Caption
****
The diagram shows the relationship between top and bottom level acceleration
structures.
****


[[acceleration-structure-geometry]]
=== Geometry

_Geometries_ refer to a triangle or axis-aligned bounding box.


[[acceleration-structure-top-level]]
=== Top Level Acceleration Structures

Opaque acceleration structure for an array of instances.
The descriptor or device address referencing this is the starting point for
traversal.

The top level acceleration structure takes a reference to any bottom level
acceleration structure referenced by its instances.
Those bottom level acceleration structure objects must: be valid when the
top level acceleration structure is accessed.


[[acceleration-structure-bottom-level]]
=== Bottom Level Acceleration Structures

Opaque acceleration structure for an array of geometries.


[[acceleration-structure-update]]
=== Acceleration Structure Update Rules

The API defines two types of operations to produce acceleration structures
from geometry:

  * A _build_ operation is used to construct an acceleration structure.
  * An _update_ operation is used to modify an existing acceleration
    structure.

An update operation imposes certain constraints on the input, in exchange
for considerably faster execution.
When performing an update, the application is required to provide a full
description of the acceleration structure, but is prohibited from changing
anything other than instance definitions, transform matrices, and vertex or
AABB positions.
All other aspects of the description must: exactly match the one from the
original build.

More precisely, the application must: not use an update operation to do any
of the following:

  * Change primitives or instances from _active_ to _inactive_ (as defined
    in <<acceleration-structure-inactive-prims>>).
  * Change the index or vertex formats of triangle geometry.
  * Change triangle geometry transform pointers from null to non-null or
    vice versa.
  * Change the number of geometries or instances in the structure.
  * Change the geometry flags for any geometry in the structure.
  * Change the number of vertices or primitives for any geometry in the
    structure.


[[acceleration-structure-inactive-prims]]
=== 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
dlink:VK_NULL_HANDLE.

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 traversal performance.

Inactive objects are counted in the auto-generated index sequences which are
provided to shaders via code:InstanceId and code: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.
Applications must: not perform an acceleration structure update where an
object is active in the source acceleration structure but would be inactive
in the destination, or vice versa.


[[acceleration-structure-building]]
=== Building Acceleration Structures

ifdef::VK_NV_ray_tracing[]
[open,refpage='vkCmdBuildAccelerationStructureNV',desc='Build an acceleration structure',type='protos']
--
:refpage: vkCmdBuildAccelerationStructureNV

To build an acceleration structure call:

include::{generated}/api/protos/vkCmdBuildAccelerationStructureNV.txt[]

  * pname:commandBuffer is the command buffer into which the command will be
    recorded.
  * pname:pInfo contains the shared information for the acceleration
    structure's structure.
  * pname:instanceData is the buffer containing an array of
    slink:VkAccelerationStructureInstanceKHR structures defining
    acceleration structures.
    This parameter must: be `NULL` for bottom level acceleration structures.
  * pname:instanceOffset is the offset in bytes (relative to the start of
    pname:instanceData) at which the instance data is located.
  * pname:update specifies whether to update the pname:dst acceleration
    structure with the data in pname:src.
  * pname:dst is a pointer to the target acceleration structure for the
    build.
  * pname:src is a pointer to an existing acceleration structure that is to
    be used to update the pname:dst acceleration structure.
  * pname:scratch is the slink:VkBuffer that will be used as scratch memory
    for the build.
  * pname:scratchOffset is the offset in bytes relative to the start of
    pname:scratch that will be used as a scratch memory.

Accesses to pname:dst, pname:src, and pname:scratch must: be
<<synchronization-dependencies,synchronized>> with the
ename:VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_KHR
<<synchronization-pipeline-stages, pipeline stage>> and an
<<synchronization-access-types, access type>> of
ename:VK_ACCESS_ACCELERATION_STRUCTURE_READ_BIT_KHR or
ename:VK_ACCESS_ACCELERATION_STRUCTURE_WRITE_BIT_KHR.

.Valid Usage
****
  * [[VUID-vkCmdBuildAccelerationStructureNV-geometryCount-02241]]
    pname:geometryCount must: be less than or equal to
    slink:VkPhysicalDeviceRayTracingPropertiesNV::pname:maxGeometryCount
  * [[VUID-vkCmdBuildAccelerationStructureNV-dst-02488]]
    pname:dst must: have been created with compatible
    slink:VkAccelerationStructureInfoNV where
    slink:VkAccelerationStructureInfoNV::pname:type and
    slink:VkAccelerationStructureInfoNV::pname:flags are identical,
    slink:VkAccelerationStructureInfoNV::pname:instanceCount and
    slink:VkAccelerationStructureInfoNV::pname:geometryCount for pname:dst
    are greater than or equal to the build size and each geometry in
    slink:VkAccelerationStructureInfoNV::pname:pGeometries for pname:dst has
    greater than or equal to the number of vertices, indices, and AABBs
  * [[VUID-vkCmdBuildAccelerationStructureNV-update-02489]]
    If pname:update is ename:VK_TRUE, pname:src must: not be
    dlink:VK_NULL_HANDLE
  * [[VUID-vkCmdBuildAccelerationStructureNV-update-02490]]
    If pname:update is ename:VK_TRUE, pname:src must: have previously been
    constructed with
    ename:VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_UPDATE_BIT_NV set in
    slink:VkAccelerationStructureInfoNV::pname:flags in the original build
  * [[VUID-vkCmdBuildAccelerationStructureNV-update-02491]]
    If pname:update is ename:VK_FALSE, the pname:size member of the
    slink:VkMemoryRequirements structure returned from a call to
    flink:vkGetAccelerationStructureMemoryRequirementsNV with
    slink:VkAccelerationStructureMemoryRequirementsInfoNV::pname:accelerationStructure
    set to pname:dst and
    slink:VkAccelerationStructureMemoryRequirementsInfoNV::pname:type set to
    ename:VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_BUILD_SCRATCH_NV
    must: be less than or equal to the size of pname:scratch minus
    pname:scratchOffset
  * [[VUID-vkCmdBuildAccelerationStructureNV-update-02492]]
    If pname:update is ename:VK_TRUE, the pname:size member of the
    slink:VkMemoryRequirements structure returned from a call to
    flink:vkGetAccelerationStructureMemoryRequirementsNV with
    slink:VkAccelerationStructureMemoryRequirementsInfoNV::pname:accelerationStructure
    set to pname:dst and
    slink:VkAccelerationStructureMemoryRequirementsInfoNV::pname:type set to
    ename:VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_UPDATE_SCRATCH_NV
    must: be less than or equal to the size of pname:scratch minus
    pname:scratchOffset
  * [[VUID-vkCmdBuildAccelerationStructureNV-scratch-03522]]
    pname:scratch must: have been created with
    ename:VK_BUFFER_USAGE_RAY_TRACING_BIT_NV usage flag
  * [[VUID-vkCmdBuildAccelerationStructureNV-instanceData-03523]]
    If pname:instanceData is not dlink:VK_NULL_HANDLE, pname:instanceData
    must: have been created with ename:VK_BUFFER_USAGE_RAY_TRACING_BIT_NV
    usage flag
  * [[VUID-vkCmdBuildAccelerationStructureNV-accelerationStructureReference-03786]]
    Each
    slink:VkAccelerationStructureInstanceKHR::pname:accelerationStructureReference
    value in pname:instanceData must: be a valid device address containing a
    value obtained from flink:vkGetAccelerationStructureHandleNV
  * [[VUID-vkCmdBuildAccelerationStructureNV-update-03524]]
    If pname:update is ename:VK_TRUE, then objects that were previously
    active must: not be made inactive as per
    <<acceleration-structure-inactive-prims>>
  * [[VUID-vkCmdBuildAccelerationStructureNV-update-03525]]
    If pname:update is ename:VK_TRUE, then objects that were previously
    inactive must: not be made active as per
    <<acceleration-structure-inactive-prims>>
  * [[VUID-vkCmdBuildAccelerationStructureNV-update-03526]]
    If pname:update is ename:VK_TRUE, the pname:src and pname:dst objects
    must: either be the same object or not have any
    <<resources-memory-aliasing, memory aliasing>>

****

include::{generated}/validity/protos/vkCmdBuildAccelerationStructureNV.txt[]
--
endif::VK_NV_ray_tracing[]

ifdef::VK_KHR_acceleration_structure[]
[open,refpage='vkCmdBuildAccelerationStructuresKHR',desc='Build an acceleration structure',type='protos']
--
:refpage: vkCmdBuildAccelerationStructuresKHR
:maxinstancecheck: pname:ppBuildRangeInfos[i][j].pname:primitiveCount

To build acceleration structures call:

include::{generated}/api/protos/vkCmdBuildAccelerationStructuresKHR.txt[]

  * pname:commandBuffer is the command buffer into which the command will be
    recorded.
  * pname:infoCount is the number of acceleration structures to build.
    It specifies the number of the pname:pInfos structures and
    pname:ppBuildRangeInfos pointers that must: be provided.
  * pname:pInfos is a pointer to an array of pname:infoCount
    slink:VkAccelerationStructureBuildGeometryInfoKHR structures defining
    the geometry used to build each acceleration structure.
  * pname:ppBuildRangeInfos is a pointer to an array of pname:infoCount
    pointers to arrays of slink:VkAccelerationStructureBuildRangeInfoKHR
    structures.
    Each pname:ppBuildRangeInfos[i] is a pointer to an array of
    pname:pInfos[i].pname:geometryCount
    slink:VkAccelerationStructureBuildRangeInfoKHR structures defining
    dynamic offsets to the addresses where geometry data is stored, as
    defined by pname:pInfos[i].

The fname:vkCmdBuildAccelerationStructuresKHR 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]
.Note
====
This means that an application cannot: build a top-level acceleration
structure in the same flink:vkCmdBuildAccelerationStructuresKHR 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.
====

[[acceleration-structure-scratch]]
Accesses to the acceleration structure scratch buffers as identified by the
slink:VkAccelerationStructureBuildGeometryInfoKHR::pname:scratchData buffer
device addresses must: be <<synchronization-dependencies,synchronized>> with
the ename:VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_KHR
<<synchronization-pipeline-stages, pipeline stage>> and an
<<synchronization-access-types, access type>> of
ename:VK_ACCESS_ACCELERATION_STRUCTURE_READ_BIT_KHR or
ename:VK_ACCESS_ACCELERATION_STRUCTURE_WRITE_BIT_KHR.
Similarly for accesses to each
slink:VkAccelerationStructureBuildGeometryInfoKHR::pname:srcAccelerationStructure
and
slink:VkAccelerationStructureBuildGeometryInfoKHR::pname:dstAccelerationStructure.

Accesses to other input buffers as identified by any used values of
ifdef::VK_NV_ray_tracing_motion_blur[]
slink:VkAccelerationStructureGeometryMotionTrianglesDataNV::pname:vertexData,
endif::VK_NV_ray_tracing_motion_blur[]
slink:VkAccelerationStructureGeometryTrianglesDataKHR::pname:vertexData,
slink:VkAccelerationStructureGeometryTrianglesDataKHR::pname:indexData,
slink:VkAccelerationStructureGeometryTrianglesDataKHR::pname:transformData,
slink:VkAccelerationStructureGeometryAabbsDataKHR::pname:data, and
slink:VkAccelerationStructureGeometryInstancesDataKHR::pname:data must: be
<<synchronization-dependencies,synchronized>> with the
ename:VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_KHR
<<synchronization-pipeline-stages, pipeline stage>> and an
<<synchronization-access-types, access type>> of
ename:VK_ACCESS_SHADER_READ_BIT.


.Valid Usage
****
include::{chapters}/commonvalidity/build_acceleration_structure_common.txt[]
include::{chapters}/commonvalidity/build_acceleration_structure_device_common.txt[]
include::{chapters}/commonvalidity/build_acceleration_structure_nonindirect_common.txt[]
****

include::{generated}/validity/protos/vkCmdBuildAccelerationStructuresKHR.txt[]
--

[open,refpage='vkCmdBuildAccelerationStructuresIndirectKHR',desc='Build an acceleration structure with some parameters provided on the device',type='protos']
--
:refpage: vkCmdBuildAccelerationStructuresIndirectKHR
:maxinstancecheck: pname:ppMaxPrimitiveCounts[i][j]

To build acceleration structures with some parameters sourced on the device
call:

include::{generated}/api/protos/vkCmdBuildAccelerationStructuresIndirectKHR.txt[]

  * pname:commandBuffer is the command buffer into which the command will be
    recorded.
  * pname:infoCount is the number of acceleration structures to build.
  * pname:pInfos is a pointer to an array of pname:infoCount
    slink:VkAccelerationStructureBuildGeometryInfoKHR structures defining
    the geometry used to build each acceleration structure.
  * pname:pIndirectDeviceAddresses is a pointer to an array of
    pname:infoCount buffer device addresses which point to
    pname:pInfos[i].pname:geometryCount
    slink:VkAccelerationStructureBuildRangeInfoKHR structures defining
    dynamic offsets to the addresses where geometry data is stored, as
    defined by pname:pInfos[i].
  * pname:pIndirectStrides is a pointer to an array of pname:infoCount byte
    strides between elements of pname:pIndirectDeviceAddresses.
  * pname:ppMaxPrimitiveCounts is a pointer to an array of pname:infoCount
    pointers to arrays of pname:pInfos[i].pname:geometryCount values
    indicating the maximum number of primitives that will be built by this
    command for each geometry.

Accesses to acceleration structures, scratch buffers, vertex buffers, index
buffers, and instance buffers must be synchronized as with
<<acceleration-structure-scratch,vkCmdBuildAccelerationStructuresKHR>>.

Accesses to any element of pname:pIndirectDeviceAddresses must: be
<<synchronization-dependencies,synchronized>> with the
ename:VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_KHR
<<synchronization-pipeline-stages, pipeline stage>> and an
<<synchronization-access-types, access type>> of
ename:VK_ACCESS_INDIRECT_COMMAND_READ_BIT.


.Valid Usage
****
include::{chapters}/commonvalidity/build_acceleration_structure_common.txt[]
include::{chapters}/commonvalidity/build_acceleration_structure_device_common.txt[]
  * [[VUID-vkCmdBuildAccelerationStructuresIndirectKHR-pIndirectDeviceAddresses-03645]]
    For any element of pname:pIndirectDeviceAddresses, if the buffer from
    which it was queried is non-sparse then it must: be bound completely and
    contiguously to a single slink:VkDeviceMemory object
  * [[VUID-vkCmdBuildAccelerationStructuresIndirectKHR-pIndirectDeviceAddresses-03646]]
    For any element of pname:pIndirectDeviceAddresses[i], all device
    addresses between pname:pIndirectDeviceAddresses[i] and
    [eq]#pname:pIndirectDeviceAddresses[i] {plus}
    (pname:pInfos[i].pname:geometryCount {times} pname:pIndirectStrides[i]) -
    1# must: be in the buffer device address range of the same buffer
  * [[VUID-vkCmdBuildAccelerationStructuresIndirectKHR-pIndirectDeviceAddresses-03647]]
    For any element of pname:pIndirectDeviceAddresses, the buffer from which
    it was queried must: have been created with the
    ename:VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT bit set
  * [[VUID-vkCmdBuildAccelerationStructuresIndirectKHR-pIndirectDeviceAddresses-03648]]
    Each element of pname:pIndirectDeviceAddresses must: be a multiple of
    `4`
  * [[VUID-vkCmdBuildAccelerationStructuresIndirectKHR-pIndirectStrides-03787]]
    Each element of pname:pIndirectStrides must: be a multiple of `4`
  * [[VUID-vkCmdBuildAccelerationStructuresIndirectKHR-commandBuffer-03649]]
    pname:commandBuffer must: not be a protected command buffer
  * [[VUID-vkCmdBuildAccelerationStructuresIndirectKHR-accelerationStructureIndirectBuild-03650]]
    The <<features-accelerationStructureIndirectBuild,
    sname:VkPhysicalDeviceAccelerationStructureFeaturesKHR::pname:accelerationStructureIndirectBuild>>
    feature must: be enabled
  * [[VUID-vkCmdBuildAccelerationStructuresIndirectKHR-pIndirectDeviceAddresses-03651]]
    Each slink:VkAccelerationStructureBuildRangeInfoKHR structure referenced
    by any element of pname:pIndirectDeviceAddresses must: be a valid
    slink:VkAccelerationStructureBuildRangeInfoKHR structure
  * [[VUID-vkCmdBuildAccelerationStructuresIndirectKHR-pInfos-03652]]
    pname:pInfos[i].pname:dstAccelerationStructure must: have been created
    with a value of slink:VkAccelerationStructureCreateInfoKHR::pname:size
    greater than or equal to the memory size required by the build
    operation, as returned by flink:vkGetAccelerationStructureBuildSizesKHR
    with [eq]#pname:pBuildInfo = pname:pInfos[i]# and
    [eq]#pname:pMaxPrimitiveCounts = pname:ppMaxPrimitiveCounts[i]#
  * [[VUID-vkCmdBuildAccelerationStructuresIndirectKHR-ppMaxPrimitiveCounts-03653]]
    Each pname:ppMaxPrimitiveCounts[i][j] must: be greater than or equal to
    the the pname:primitiveCount value specified by the
    slink:VkAccelerationStructureBuildRangeInfoKHR structure located at
    [eq]#pname:pIndirectDeviceAddresses[i] {plus} (code:j {times}
    pname:pIndirectStrides[i])#
****

include::{generated}/validity/protos/vkCmdBuildAccelerationStructuresIndirectKHR.txt[]
--


[open,refpage='VkAccelerationStructureBuildGeometryInfoKHR',desc='Structure specifying the geometry data used to build an acceleration structure',type='structs']
--
:refpage: VkAccelerationStructureBuildGeometryInfoKHR

The sname:VkAccelerationStructureBuildGeometryInfoKHR structure is defined
as:

include::{generated}/api/structs/VkAccelerationStructureBuildGeometryInfoKHR.txt[]

  * pname:sType is the type of this structure.
  * pname:pNext is `NULL` or a pointer to a structure extending this
    structure.
  * pname:type is a elink:VkAccelerationStructureTypeKHR value specifying
    the type of acceleration structure being built.
  * pname:flags is a bitmask of
    elink:VkBuildAccelerationStructureFlagBitsKHR specifying additional
    parameters of the acceleration structure.
  * pname:mode is a elink:VkBuildAccelerationStructureModeKHR value
    specifying the type of operation to perform.
  * pname:srcAccelerationStructure is a pointer to an existing acceleration
    structure that is to be used to update the pname:dst acceleration
    structure when pname:mode is
    ename:VK_BUILD_ACCELERATION_STRUCTURE_MODE_UPDATE_KHR.
  * pname:dstAccelerationStructure is a pointer to the target acceleration
    structure for the build.
  * pname:geometryCount specifies the number of geometries that will be
    built into pname:dstAccelerationStructure.
  * pname:pGeometries is a pointer to an array of
    slink:VkAccelerationStructureGeometryKHR structures.
  * pname:ppGeometries is a pointer to an array of pointers to
    slink:VkAccelerationStructureGeometryKHR structures.
  * pname:scratchData is the device or host address to memory that will be
    used as scratch memory for the build.

Only one of pname:pGeometries or pname:ppGeometries can: be a valid pointer,
the other must: be `NULL`.
Each element of the non-`NULL` array describes the data used to build each
acceleration structure geometry.

ifdef::VK_KHR_ray_tracing_pipeline,VK_KHR_ray_query[]
[[acceleration-structure-geometry-index]]
The index of each element of the pname:pGeometries or pname:ppGeometries
members of slink:VkAccelerationStructureBuildGeometryInfoKHR is used as the
_geometry index_ during ray traversal.
ifdef::VK_KHR_ray_tracing_pipeline[]
The geometry index is available in ray shaders via the
<<interfaces-builtin-variables-raygeometryindex,code:RayGeometryIndexKHR
built-in>>, and is <<shader-binding-table-hit-shader-indexing, used to
determine hit and intersection shaders executed during traversal>>.
endif::VK_KHR_ray_tracing_pipeline[]
ifdef::VK_KHR_ray_query[]
The geometry index is available to ray queries via the
code:OpRayQueryGetIntersectionGeometryIndexKHR instruction.
endif::VK_KHR_ray_query[]
endif::VK_KHR_ray_tracing_pipeline,VK_KHR_ray_query[]

ifdef::VK_NV_ray_tracing_motion_blur[]
[[acceleration-structure-motion-instances]]
Setting ename:VK_BUILD_ACCELERATION_STRUCTURE_MOTION_BIT_NV in pname:flags
indicates that this build is a motion top level acceleration structure.
A motion top level uses instances of format
slink:VkAccelerationStructureMotionInstanceNV if
slink:VkAccelerationStructureGeometryInstancesDataKHR::pname:arrayOfPointers
is ename:VK_FALSE.

If
slink:VkAccelerationStructureGeometryInstancesDataKHR::pname:arrayOfPointers
is ename:VK_TRUE, the pointer for any given element of the array of instance
pointers consists of 4 bits of
ename:VkAccelerationStructureMotionInstanceTypeNV in the low 4 bits of the
pointer identifying the type of structure at the pointer.
The device address accessed is the value in the array with the low 4 bits
set to zero.
The structure at the pointer is one of
slink:VkAccelerationStructureInstanceKHR,
slink:VkAccelerationStructureMatrixMotionInstanceNV or
slink:VkAccelerationStructureSRTMotionInstanceNV, depending on the type
value encoded in the low 4 bits.

A top level acceleration structure with either motion instances or vertex
motion in its instances must: set
ename:VK_BUILD_ACCELERATION_STRUCTURE_MOTION_BIT_NV in pname:flags.
endif::VK_NV_ray_tracing_motion_blur[]

Members pname:srcAccelerationStructure and pname:dstAccelerationStructure
may: be the same or different for an update operation (when pname:mode is
ename:VK_BUILD_ACCELERATION_STRUCTURE_MODE_UPDATE_KHR).
If they are the same, the update happens in-place.
Otherwise, the target acceleration structure is updated and the source is
not modified.

.Valid Usage
****
  * [[VUID-VkAccelerationStructureBuildGeometryInfoKHR-type-03654]]
    pname:type must: not be ename:VK_ACCELERATION_STRUCTURE_TYPE_GENERIC_KHR
  * [[VUID-VkAccelerationStructureBuildGeometryInfoKHR-pGeometries-03788]]
    Only one of pname:pGeometries or pname:ppGeometries can: be a valid
    pointer, the other must: be `NULL`
  * [[VUID-VkAccelerationStructureBuildGeometryInfoKHR-type-03789]]
    If pname:type is ename:VK_ACCELERATION_STRUCTURE_TYPE_TOP_LEVEL_KHR, the
    pname:geometryType member of elements of either pname:pGeometries or
    pname:ppGeometries must: be ename:VK_GEOMETRY_TYPE_INSTANCES_KHR
  * [[VUID-VkAccelerationStructureBuildGeometryInfoKHR-type-03790]]
    If pname:type is ename:VK_ACCELERATION_STRUCTURE_TYPE_TOP_LEVEL_KHR,
    pname:geometryCount must: be `1`
  * [[VUID-VkAccelerationStructureBuildGeometryInfoKHR-type-03791]]
    If pname:type is ename:VK_ACCELERATION_STRUCTURE_TYPE_BOTTOM_LEVEL_KHR
    the pname:geometryType member of elements of either pname:pGeometries or
    pname:ppGeometries must: not be ename:VK_GEOMETRY_TYPE_INSTANCES_KHR
  * [[VUID-VkAccelerationStructureBuildGeometryInfoKHR-type-03792]]
    If pname:type is ename:VK_ACCELERATION_STRUCTURE_TYPE_BOTTOM_LEVEL_KHR
    then the pname:geometryType member of each geometry in either
    pname:pGeometries or pname:ppGeometries must: be the same
  * [[VUID-VkAccelerationStructureBuildGeometryInfoKHR-type-03793]]
    If pname:type is ename:VK_ACCELERATION_STRUCTURE_TYPE_BOTTOM_LEVEL_KHR
    then pname:geometryCount must: be less than or equal to
    slink:VkPhysicalDeviceAccelerationStructurePropertiesKHR::pname:maxGeometryCount
  * [[VUID-VkAccelerationStructureBuildGeometryInfoKHR-type-03794]]
    If pname:type is ename:VK_ACCELERATION_STRUCTURE_TYPE_BOTTOM_LEVEL_KHR
    and the pname:geometryType member of either pname:pGeometries or
    pname:ppGeometries is ename:VK_GEOMETRY_TYPE_AABBS_KHR, the total number
    of AABBs in all geometries must: be less than or equal to
    slink:VkPhysicalDeviceAccelerationStructurePropertiesKHR::pname:maxPrimitiveCount
  * [[VUID-VkAccelerationStructureBuildGeometryInfoKHR-type-03795]]
    If pname:type is ename:VK_ACCELERATION_STRUCTURE_TYPE_BOTTOM_LEVEL_KHR
    and the pname:geometryType member of either pname:pGeometries or
    pname:ppGeometries is ename:VK_GEOMETRY_TYPE_TRIANGLES_KHR, the total
    number of triangles in all geometries must: be less than or equal to
    slink:VkPhysicalDeviceAccelerationStructurePropertiesKHR::pname:maxPrimitiveCount
  * [[VUID-VkAccelerationStructureBuildGeometryInfoKHR-flags-03796]]
    If pname:flags has the
    ename:VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_TRACE_BIT_KHR bit set,
    then it must: not have the
    ename:VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_BUILD_BIT_KHR bit set
ifdef::VK_NV_ray_tracing_motion_blur[]
  * [[VUID-VkAccelerationStructureBuildGeometryInfoKHR-dstAccelerationStructure-04927]]
    If pname:dstAccelerationStructure was created with
    ename:VK_ACCELERATION_STRUCTURE_CREATE_MOTION_BIT_NV set in
    slink:VkAccelerationStructureCreateInfoKHR::pname:flags,
    ename:VK_BUILD_ACCELERATION_STRUCTURE_MOTION_BIT_NV must: be set in
    pname:flags
  * [[VUID-VkAccelerationStructureBuildGeometryInfoKHR-flags-04928]]
    If ename:VK_BUILD_ACCELERATION_STRUCTURE_MOTION_BIT_NV is set in
    pname:flags, pname:dstAccelerationStructure must: have been created with
    ename:VK_ACCELERATION_STRUCTURE_CREATE_MOTION_BIT_NV set in
    slink:VkAccelerationStructureCreateInfoKHR::pname:flags
  * [[VUID-VkAccelerationStructureBuildGeometryInfoKHR-flags-04929]]
    If ename:VK_BUILD_ACCELERATION_STRUCTURE_MOTION_BIT_NV is set in
    pname:flags, pname:type must: not be
    ename:VK_ACCELERATION_STRUCTURE_TYPE_GENERIC_KHR
endif::VK_NV_ray_tracing_motion_blur[]
****
include::{generated}/validity/structs/VkAccelerationStructureBuildGeometryInfoKHR.txt[]
--

[open,refpage='VkBuildAccelerationStructureModeKHR',desc='Enum specifying the type of build operation to perform',type='enums']
--
:refpage: VkBuildAccelerationStructureModeKHR

The ename:VkBuildAccelerationStructureModeKHR enumeration is defined as:

include::{generated}/api/enums/VkBuildAccelerationStructureModeKHR.txt[]

  * ename:VK_BUILD_ACCELERATION_STRUCTURE_MODE_BUILD_KHR specifies that the
    destination acceleration structure will be built using the specified
    geometries.
  * ename:VK_BUILD_ACCELERATION_STRUCTURE_MODE_UPDATE_KHR specifies that the
    destination acceleration structure will be built using data in a source
    acceleration structure, updated by the specified geometries.
--

[open,refpage='VkDeviceOrHostAddressKHR',desc='Union specifying a device or host address',type='structs']
--
:refpage: VkDeviceOrHostAddressKHR

The sname:VkDeviceOrHostAddressKHR union is defined as:

include::{generated}/api/structs/VkDeviceOrHostAddressKHR.txt[]

  * pname:deviceAddress is a buffer device address as returned by the
    flink:vkGetBufferDeviceAddressKHR command.
  * pname:hostAddress is a host memory address.

include::{generated}/validity/structs/VkDeviceOrHostAddressKHR.txt[]
--

[open,refpage='VkDeviceOrHostAddressConstKHR',desc='Union specifying a const device or host address',type='structs']
--
:refpage: VkDeviceOrHostAddressConstKHR

The sname:VkDeviceOrHostAddressConstKHR union is defined as:

include::{generated}/api/structs/VkDeviceOrHostAddressConstKHR.txt[]

  * pname:deviceAddress is a buffer device address as returned by the
    flink:vkGetBufferDeviceAddressKHR command.
  * pname:hostAddress is a const host memory address.

include::{generated}/validity/structs/VkDeviceOrHostAddressConstKHR.txt[]
--

[open,refpage='VkAccelerationStructureGeometryKHR',desc='Structure specifying geometries to be built into an acceleration structure',type='structs']
--
:refpage: VkAccelerationStructureGeometryKHR

The sname:VkAccelerationStructureGeometryKHR structure is defined as:

include::{generated}/api/structs/VkAccelerationStructureGeometryKHR.txt[]

  * pname:sType is the type of this structure.
  * pname:pNext is `NULL` or a pointer to a structure extending this
    structure.
  * pname:geometryType describes which type of geometry this
    sname:VkAccelerationStructureGeometryKHR refers to.
  * pname:geometry is a slink:VkAccelerationStructureGeometryDataKHR union
    describing the geometry data for the relevant geometry type.
  * pname:flags is a bitmask of elink:VkGeometryFlagBitsKHR values
    describing additional properties of how the geometry should be built.

include::{generated}/validity/structs/VkAccelerationStructureGeometryKHR.txt[]
--

[open,refpage='VkAccelerationStructureGeometryDataKHR',desc='Union specifying acceleration structure geometry data',type='structs']
--
:refpage: VkAccelerationStructureGeometryDataKHR

The sname:VkAccelerationStructureGeometryDataKHR union is defined as:

include::{generated}/api/structs/VkAccelerationStructureGeometryDataKHR.txt[]

  * pname:triangles is a
    slink:VkAccelerationStructureGeometryTrianglesDataKHR structure.
  * pname:aabbs is a slink:VkAccelerationStructureGeometryAabbsDataKHR
    struture.
  * pname:instances is a
    slink:VkAccelerationStructureGeometryInstancesDataKHR structure.

include::{generated}/validity/structs/VkAccelerationStructureGeometryDataKHR.txt[]
--

[open,refpage='VkAccelerationStructureGeometryTrianglesDataKHR',desc='Structure specifying a triangle geometry in a bottom-level acceleration structure',type='structs']
--
:refpage: VkAccelerationStructureGeometryTrianglesDataKHR

The sname:VkAccelerationStructureGeometryTrianglesDataKHR structure is
defined as:

include::{generated}/api/structs/VkAccelerationStructureGeometryTrianglesDataKHR.txt[]

  * pname:sType is the type of this structure.
  * pname:pNext is `NULL` or a pointer to a structure extending this
    structure.
  * pname:vertexFormat is the elink:VkFormat of each vertex element.
  * pname:vertexData is a device or host address to memory containing vertex
    data for this geometry.
  * pname:maxVertex is the highest index of a vertex that will be addressed
    by a build command using this structure.
  * pname:vertexStride is the stride in bytes between each vertex.
  * pname:indexType is the elink:VkIndexType of each index element.
  * pname:indexData is a device or host address to memory containing index
    data for this geometry.
  * pname:transformData is a device or host address to memory containing an
    optional reference to a slink:VkTransformMatrixKHR structure that
    describes a transformation from the space in which the vertices in this
    geometry are described to the space in which the acceleration structure
    is defined.

[NOTE]
.Note
====
Unlike the stride for vertex buffers in
slink:VkVertexInputBindingDescription for graphics pipelines which must not
exceed pname:maxVertexInputBindingStride, pname:vertexStride for
acceleration structure geometry is instead restricted to being a 32-bit
value.
====

.Valid Usage
****
  * [[VUID-VkAccelerationStructureGeometryTrianglesDataKHR-vertexStride-03735]]
    pname:vertexStride must: be a multiple of the size in bytes of the
    smallest component of pname:vertexFormat
  * [[VUID-VkAccelerationStructureGeometryTrianglesDataKHR-vertexStride-03819]]
    pname:vertexStride must: be less than or equal to [eq]#2^32^-1#
  * [[VUID-VkAccelerationStructureGeometryTrianglesDataKHR-vertexFormat-03797]]
    pname:vertexFormat must: support the
    ename:VK_FORMAT_FEATURE_ACCELERATION_STRUCTURE_VERTEX_BUFFER_BIT_KHR in
    slink:VkFormatProperties::pname:bufferFeatures as returned by
    flink:vkGetPhysicalDeviceFormatProperties2
  * [[VUID-VkAccelerationStructureGeometryTrianglesDataKHR-indexType-03798]]
    pname:indexType must: be ename:VK_INDEX_TYPE_UINT16,
    ename:VK_INDEX_TYPE_UINT32, or ename:VK_INDEX_TYPE_NONE_KHR
****

include::{generated}/validity/structs/VkAccelerationStructureGeometryTrianglesDataKHR.txt[]
--

ifdef::VK_NV_ray_tracing_motion_blur[]
[open,refpage='VkAccelerationStructureGeometryMotionTrianglesDataNV',desc='Structure specifying vertex motion in a bottom-level acceleration structure',type='structs']
--
:refpage: VkAccelerationStructureGeometryMotionTrianglesDataNV

The sname:VkAccelerationStructureGeometryMotionTrianglesDataNV structure is
defined as:

include::{generated}/api/structs/VkAccelerationStructureGeometryMotionTrianglesDataNV.txt[]

  * pname:sType is the type of this structure.
  * pname:pNext is `NULL` or a pointer to a structure extending this
    structure.
  * pname:vertexData is a pointer to vertex data for this geometry at time
    1.0

If sname:VkAccelerationStructureGeometryMotionTrianglesDataNV is included in
the pname:pNext chain of a
slink:VkAccelerationStructureGeometryTrianglesDataKHR structure, the basic
vertex positions are used for the position of the triangles in the geometry
at time 0.0 and the pname:vertexData in
sname:VkAccelerationStructureGeometryMotionTrianglesDataNV is used for the
vertex positions at time 1.0, with positions linearly interpolated at
intermediate times.

Indexing for sname:VkAccelerationStructureGeometryMotionTrianglesDataNV
pname:vertexData is equivalent to the basic vertex position data.

include::{generated}/validity/structs/VkAccelerationStructureGeometryMotionTrianglesDataNV.txt[]
--
endif::VK_NV_ray_tracing_motion_blur[]
endif::VK_KHR_acceleration_structure[]

[open,refpage='VkTransformMatrixKHR',desc='Structure specifying a 3x4 affine transformation matrix',type='structs',alias='VkTransformMatrixNV']
--
:refpage: VkTransformMatrixKHR

The sname:VkTransformMatrixKHR structure is defined as:

include::{generated}/api/structs/VkTransformMatrixKHR.txt[]

ifdef::VK_NV_ray_tracing[]
or the equivalent

include::{generated}/api/structs/VkTransformMatrixNV.txt[]
endif::VK_NV_ray_tracing[]

  * pname:matrix is a 3x4 row-major affine transformation matrix.

include::{generated}/validity/structs/VkTransformMatrixKHR.txt[]

.Valid Usage
****
  * [[VUID-VkTransformMatrixKHR-matrix-03799]]
    The first three columns of pname:matrix must: define an invertible 3x3
    matrix
****
--

ifdef::VK_KHR_acceleration_structure[]
[open,refpage='VkAccelerationStructureGeometryAabbsDataKHR',desc='Structure specifying axis-aligned bounding box geometry in a bottom-level acceleration structure',type='structs']
--
:refpage: VkAccelerationStructureGeometryAabbsDataKHR

The sname:VkAccelerationStructureGeometryAabbsDataKHR structure is defined
as:

include::{generated}/api/structs/VkAccelerationStructureGeometryAabbsDataKHR.txt[]

  * pname:sType is the type of this structure.
  * pname:pNext is `NULL` or a pointer to a structure extending this
    structure.
  * pname:data is a device or host address to memory containing
    slink:VkAabbPositionsKHR structures containing position data for each
    axis-aligned bounding box in the geometry.
  * pname:stride is the stride in bytes between each entry in pname:data.
    The stride must: be a multiple of `8`.

.Valid Usage
****
  * [[VUID-VkAccelerationStructureGeometryAabbsDataKHR-stride-03545]]
    pname:stride must: be a multiple of `8`
  * [[VUID-VkAccelerationStructureGeometryAabbsDataKHR-stride-03820]]
    pname:stride must: be less than or equal to [eq]#2^32^-1#
****

include::{generated}/validity/structs/VkAccelerationStructureGeometryAabbsDataKHR.txt[]
--
endif::VK_KHR_acceleration_structure[]

[open,refpage='VkAabbPositionsKHR',desc='Structure specifying two opposing corners of an axis-aligned bounding box',type='structs',alias='VkAabbPositionsNV']
--
:refpage: VkAabbPositionsKHR

The sname:VkAabbPositionsKHR structure is defined as:

include::{generated}/api/structs/VkAabbPositionsKHR.txt[]

ifdef::VK_NV_ray_tracing[]
or the equivalent

include::{generated}/api/structs/VkAabbPositionsNV.txt[]
endif::VK_NV_ray_tracing[]


  * pname:minX is the x position of one opposing corner of a bounding box.
  * pname:minY is the y position of one opposing corner of a bounding box.
  * pname:minZ is the z position of one opposing corner of a bounding box.
  * pname:maxX is the x position of the other opposing corner of a bounding
    box.
  * pname:maxY is the y position of the other opposing corner of a bounding
    box.
  * pname:maxZ is the z position of the other opposing corner of a bounding
    box.

.Valid Usage
****
  * [[VUID-VkAabbPositionsKHR-minX-03546]]
    pname:minX must: be less than or equal to pname:maxX
  * [[VUID-VkAabbPositionsKHR-minY-03547]]
    pname:minY must: be less than or equal to pname:maxY
  * [[VUID-VkAabbPositionsKHR-minZ-03548]]
    pname:minZ must: be less than or equal to pname:maxZ
****

include::{generated}/validity/structs/VkAabbPositionsKHR.txt[]
--

ifdef::VK_KHR_acceleration_structure[]
[open,refpage='VkAccelerationStructureGeometryInstancesDataKHR',desc='Structure specifying a geometry consisting of instances of other acceleration structures',type='structs']
--
:refpage: VkAccelerationStructureGeometryInstancesDataKHR

The sname:VkAccelerationStructureGeometryInstancesDataKHR structure is
defined as:

include::{generated}/api/structs/VkAccelerationStructureGeometryInstancesDataKHR.txt[]

  * pname:sType is the type of this structure.
  * pname:pNext is `NULL` or a pointer to a structure extending this
    structure.
  * pname:arrayOfPointers specifies whether pname:data is used as an array
    of addresses or just an array.
  * pname:data is either the address of an array of device or host addresses
    referencing individual slink:VkAccelerationStructureInstanceKHR
    structures
ifdef::VK_NV_ray_tracing_motion_blur[]
    or packed motion instance information as described in
    <<acceleration-structure-motion-instances, motion instances>>
endif::VK_NV_ray_tracing_motion_blur[]
    if pname:arrayOfPointers is ename:VK_TRUE, or the address of an array of
    slink:VkAccelerationStructureInstanceKHR
ifdef::VK_NV_ray_tracing_motion_blur[]
    or slink:VkAccelerationStructureMotionInstanceNV
endif::VK_NV_ray_tracing_motion_blur[]
    structures.
    Addresses and slink:VkAccelerationStructureInstanceKHR structures are
    tightly packed.
ifdef::VK_NV_ray_tracing_motion_blur[]
    slink:VkAccelerationStructureMotionInstanceNV structures have a stride
    of 160 bytes.
endif::VK_NV_ray_tracing_motion_blur[]

include::{generated}/validity/structs/VkAccelerationStructureGeometryInstancesDataKHR.txt[]
--
endif::VK_KHR_acceleration_structure[]

[open,refpage='VkAccelerationStructureInstanceKHR',desc='Structure specifying a single acceleration structure instance for building into an acceleration structure geometry',type='structs',alias='VkAccelerationStructureInstanceNV']
--
:refpage: VkAccelerationStructureInstanceKHR

_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:

include::{generated}/api/structs/VkAccelerationStructureInstanceKHR.txt[]

ifdef::VK_NV_ray_tracing[]
or the equivalent

include::{generated}/api/structs/VkAccelerationStructureInstanceNV.txt[]
endif::VK_NV_ray_tracing[]

  * pname:transform is a slink:VkTransformMatrixKHR structure describing a
    transformation to be applied to the acceleration structure.
  * pname:instanceCustomIndex is a 24-bit user-specified index value
    accessible to ray shaders in the code:InstanceCustomIndexKHR built-in.
  * pname:mask is an 8-bit visibility mask for the geometry.
    The instance may: only be hit if `Cull Mask & instance.mask != 0`
  * pname:instanceShaderBindingTableRecordOffset is a 24-bit offset used in
    calculating the hit shader binding table index.
  * pname:flags is an 8-bit mask of elink:VkGeometryInstanceFlagBitsKHR
    values to apply to this instance.
  * pname:accelerationStructureReference is either:
  ** a device address containing the value obtained from
ifdef::VK_KHR_acceleration_structure[flink:vkGetAccelerationStructureDeviceAddressKHR]
ifdef::VK_KHR_acceleration_structure+VK_NV_ray_tracing[or]
ifdef::VK_NV_ray_tracing[flink:vkGetAccelerationStructureHandleNV]
     (used by device operations which reference acceleration structures) or,
  ** a slink:VkAccelerationStructureKHR object (used by host operations
     which reference acceleration structures).

The C language specification 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:

  * pname:instanceCustomIndex and pname:mask occupy the same memory as if a
    single code:uint32_t was specified in their place
  ** pname:instanceCustomIndex occupies the 24 least significant bits of
     that memory
  ** pname:mask occupies the 8 most significant bits of that memory
  * pname:instanceShaderBindingTableRecordOffset and pname:flags occupy the
    same memory as if a single code:uint32_t was specified in their place
  ** pname:instanceShaderBindingTableRecordOffset occupies the 24 least
     significant bits of that memory
  ** pname: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.

include::{generated}/validity/structs/VkAccelerationStructureInstanceKHR.txt[]
--

[open,refpage='VkGeometryInstanceFlagBitsKHR',desc='Instance flag bits',type='enums',alias='VkGeometryInstanceFlagBitsNV']
--
:refpage: VkGeometryInstanceFlagBitsKHR

Possible values of pname:flags in the instance modifying the behavior of
that instance are:

include::{generated}/api/enums/VkGeometryInstanceFlagBitsKHR.txt[]

ifdef::VK_NV_ray_tracing[]
or the equivalent

include::{generated}/api/enums/VkGeometryInstanceFlagBitsNV.txt[]
endif::VK_NV_ray_tracing[]

  * ename:VK_GEOMETRY_INSTANCE_TRIANGLE_FACING_CULL_DISABLE_BIT_KHR disables
    face culling for this instance.
  * ename:VK_GEOMETRY_INSTANCE_TRIANGLE_FLIP_FACING_BIT_KHR indicates that
    the <<ray-traversal-culling-face, facing determination>> for geometry in
    this instance is inverted.
    Because the facing is determined in object space, an instance transform
    does not change the winding, but a geometry transform does.
  * ename:VK_GEOMETRY_INSTANCE_FORCE_OPAQUE_BIT_KHR causes this instance to
    act as though ename:VK_GEOMETRY_OPAQUE_BIT_KHR were specified on all
    geometries referenced by this instance.
    This behavior can: be overridden by the SPIR-V code:NoOpaqueKHR ray
    flag.
  * ename:VK_GEOMETRY_INSTANCE_FORCE_NO_OPAQUE_BIT_KHR causes this instance
    to act as though ename:VK_GEOMETRY_OPAQUE_BIT_KHR were not specified on
    all geometries referenced by this instance.
    This behavior can: be overridden by the SPIR-V code:OpaqueKHR ray flag.

ename:VK_GEOMETRY_INSTANCE_FORCE_NO_OPAQUE_BIT_KHR and
ename:VK_GEOMETRY_INSTANCE_FORCE_OPAQUE_BIT_KHR must: not be used in the
same flag.
--

[open,refpage='VkGeometryInstanceFlagsKHR',desc='Bitmask of VkGeometryInstanceFlagBitsKHR',type='flags',alias='VkGeometryInstanceFlagsNV']
--
:refpage: VkGeometryInstanceFlagsKHR

include::{generated}/api/flags/VkGeometryInstanceFlagsKHR.txt[]

ifdef::VK_NV_ray_tracing[]
or the equivalent

include::{generated}/api/flags/VkGeometryInstanceFlagsNV.txt[]
endif::VK_NV_ray_tracing[]

tname:VkGeometryInstanceFlagsKHR is a bitmask type for setting a mask of
zero or more elink:VkGeometryInstanceFlagBitsKHR.
--

ifdef::VK_NV_ray_tracing_motion_blur[]
[open,refpage='VkAccelerationStructureMotionInstanceNV',desc='Structure specifying a single acceleration structure motion instance for building into an acceleration structure geometry',type='structs']
--
:refpage: VkAccelerationStructureMotionInstanceNV

_Acceleration structure motion 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 including a type of motion
and parameters to determine the motion of the instance over time.

An acceleration structure motion instance is defined by the structure:

include::{generated}/api/structs/VkAccelerationStructureMotionInstanceNV.txt[]

  * pname:type is a elink:VkAccelerationStructureMotionInstanceTypeNV
    enumerant identifying which type of motion instance this is and which
    type of the union is valid.
  * pname:flags is currently unused, but is required to keep natural
    alignment of pname:data.
  * pname:data is a slink:VkAccelerationStructureMotionInstanceDataNV
    containing motion instance data for this instance.

[NOTE]
.Note
====
If writing this other than with a standard C compiler, note that the final
structure should be 152 bytes in size.
====

include::{generated}/validity/structs/VkAccelerationStructureMotionInstanceNV.txt[]
--

[open,refpage='VkAccelerationStructureMotionInstanceDataNV',desc='Union specifying a acceleration structure motion instance data for building into an acceleration structure geometry',type='structs']
--
:refpage: VkAccelerationStructureMotionInstanceDataNV

Acceleration structure motion instance is defined by the union:

include::{generated}/api/structs/VkAccelerationStructureMotionInstanceDataNV.txt[]

  * pname:staticInstance is a slink:VkAccelerationStructureInstanceKHR
    structure containing data for a static instance.
  * pname:matrixMotionInstance is a
    slink:VkAccelerationStructureMatrixMotionInstanceNV structure containing
    data for a matrix motion instance.
  * pname:srtMotionInstance is a
    slink:VkAccelerationStructureSRTMotionInstanceNV structure containing
    data for an SRT motion instance.

include::{generated}/validity/structs/VkAccelerationStructureMotionInstanceDataNV.txt[]
--

[open,refpage='VkAccelerationStructureMotionInstanceFlagsNV',desc='Reserved for future use',type='flags']
--
include::{generated}/api/flags/VkAccelerationStructureMotionInstanceFlagsNV.txt[]

tname:VkAccelerationStructureMotionInstanceFlagsNV is a bitmask type for
setting a mask, but is currently reserved for future use.
--

[open,refpage='VkAccelerationStructureMotionInstanceTypeNV',desc='Enum specifying a type of acceleration structure motion instance data for building into an acceleration structure geometry',type='enums']
--
:refpage: VkAccelerationStructureMotionInstanceTypeNV

The ename:VkAccelerationStructureMotionInstanceTypeNV enumeration is defined
as:

include::{generated}/api/enums/VkAccelerationStructureMotionInstanceTypeNV.txt[]

  * ename:VK_ACCELERATION_STRUCTURE_MOTION_INSTANCE_TYPE_STATIC_NV specifies
    that the instance is a static instance with no instance motion.
  * ename:VK_ACCELERATION_STRUCTURE_MOTION_INSTANCE_TYPE_MATRIX_MOTION_NV
    specifies that the instance is a motion instance with motion specified
    by interpolation between two matrices.
  * ename:VK_ACCELERATION_STRUCTURE_MOTION_INSTANCE_TYPE_SRT_MOTION_NV
    specifies that the instance is a motion instance with motion specified
    by interpolation in the SRT decomposition.
--

[open,refpage='VkAccelerationStructureMatrixMotionInstanceNV',desc='Structure specifying a single acceleration structure matrix motion instance for building into an acceleration structure geometry',type='structs']
--
:refpage: VkAccelerationStructureMatrixMotionInstanceNV

An acceleration structure matrix motion instance is defined by the
structure:

include::{generated}/api/structs/VkAccelerationStructureMatrixMotionInstanceNV.txt[]

  * pname:transformT0 is a slink:VkTransformMatrixKHR structure describing a
    transformation to be applied to the acceleration structure at time 0.
  * pname:transformT1 is a slink:VkTransformMatrixKHR structure describing a
    transformation to be applied to the acceleration structure at time 1.
  * pname:instanceCustomIndex is a 24-bit user-specified index value
    accessible to ray shaders in the code:InstanceCustomIndexKHR built-in.
  * pname:mask is an 8-bit visibility mask for the geometry.
    The instance may: only be hit if `Cull Mask & instance.mask != 0`
  * pname:instanceShaderBindingTableRecordOffset is a 24-bit offset used in
    calculating the hit shader binding table index.
  * pname:flags is an 8-bit mask of elink:VkGeometryInstanceFlagBitsKHR
    values to apply to this instance.
  * pname:accelerationStructureReference is either:
  ** a device address containing the value obtained from
ifdef::VK_KHR_acceleration_structure[flink:vkGetAccelerationStructureDeviceAddressKHR]
ifdef::VK_KHR_acceleration_structure+VK_NV_ray_tracing[or]
ifdef::VK_NV_ray_tracing[flink:vkGetAccelerationStructureHandleNV]
     (used by device operations which reference acceleration structures) or,
  ** a slink:VkAccelerationStructureKHR object (used by host operations
     which reference acceleration structures).

The C language specification 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:

  * pname:instanceCustomIndex and pname:mask occupy the same memory as if a
    single code:uint32_t was specified in their place
  ** pname:instanceCustomIndex occupies the 24 least significant bits of
     that memory
  ** pname:mask occupies the 8 most significant bits of that memory
  * pname:instanceShaderBindingTableRecordOffset and pname:flags occupy the
    same memory as if a single code:uint32_t was specified in their place
  ** pname:instanceShaderBindingTableRecordOffset occupies the 24 least
     significant bits of that memory
  ** pname: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.

The transform for a matrix motion instance at a point in time is derived by
component-wise linear interpolation of the two transforms.
That is, for a code:time in [0,1] the resulting transform is

  {empty}:: [eq]#pname:transformT0 {times} (1 - code:time) {plus}
            pname:transformT1 {times} code:time#

include::{generated}/validity/structs/VkAccelerationStructureMatrixMotionInstanceNV.txt[]
--

[open,refpage='VkAccelerationStructureSRTMotionInstanceNV',desc='Structure specifying a single acceleration structure SRT motion instance for building into an acceleration structure geometry',type='structs']
--
:refpage: VkAccelerationStructureSRTMotionInstanceNV

An acceleration structure SRT motion instance is defined by the structure:

include::{generated}/api/structs/VkAccelerationStructureSRTMotionInstanceNV.txt[]

  * pname:transformT0 is a slink:VkSRTDataNV structure describing a
    transformation to be applied to the acceleration structure at time 0.
  * pname:transformT1 is a slink:VkSRTDataNV structure describing a
    transformation to be applied to the acceleration structure at time 1.
  * pname:instanceCustomIndex is a 24-bit user-specified index value
    accessible to ray shaders in the code:InstanceCustomIndexKHR built-in.
  * pname:mask is an 8-bit visibility mask for the geometry.
    The instance may: only be hit if `Cull Mask & instance.mask != 0`
  * pname:instanceShaderBindingTableRecordOffset is a 24-bit offset used in
    calculating the hit shader binding table index.
  * pname:flags is an 8-bit mask of elink:VkGeometryInstanceFlagBitsKHR
    values to apply to this instance.
  * pname:accelerationStructureReference is either:
  ** a device address containing the value obtained from
ifdef::VK_KHR_acceleration_structure[flink:vkGetAccelerationStructureDeviceAddressKHR]
ifdef::VK_KHR_acceleration_structure+VK_NV_ray_tracing[or]
ifdef::VK_NV_ray_tracing[flink:vkGetAccelerationStructureHandleNV]
     (used by device operations which reference acceleration structures) or,
  ** a slink:VkAccelerationStructureKHR object (used by host operations
     which reference acceleration structures).

The C language specification 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:

  * pname:instanceCustomIndex and pname:mask occupy the same memory as if a
    single code:uint32_t was specified in their place
  ** pname:instanceCustomIndex occupies the 24 least significant bits of
     that memory
  ** pname:mask occupies the 8 most significant bits of that memory
  * pname:instanceShaderBindingTableRecordOffset and pname:flags occupy the
    same memory as if a single code:uint32_t was specified in their place
  ** pname:instanceShaderBindingTableRecordOffset occupies the 24 least
     significant bits of that memory
  ** pname: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.

The transform for a SRT motion instance at a point in time is derived from
component-wise linear interpolation of the two SRT transforms.
That is, for a code:time in [0,1] the resulting transform is

  {empty}:: [eq]#pname:transformT0 {times} (1 - code:time) {plus}
            pname:transformT1 {times} code:time#

include::{generated}/validity/structs/VkAccelerationStructureSRTMotionInstanceNV.txt[]
--

[open,refpage='VkSRTDataNV',desc='Structure specifying a transform in SRT decomposition',type='structs']
--
:refpage: VkSRTDataNV

An acceleration structure SRT transform is defined by the structure:

include::{generated}/api/structs/VkSRTDataNV.txt[]

  * pname:sx is the x component of the scale of the transform
  * pname:a is one component of the shear for the transform
  * pname:b is one component of the shear for the transform
  * pname:pvx is the x component of the pivot point of the transform
  * pname:sy is the y component of the scale of the transform
  * pname:c is one component of the shear for the transform
  * pname:pvy is the y component of the pivot point of the transform
  * pname:sz is the z component of the scale of the transform
  * pname:pvz is the z component of the pivot point of the transform
  * pname:qx is the x component of the rotation quaternion
  * pname:qy is the y component of the rotation quaternion
  * pname:qz is the z component of the rotation quaternion
  * pname:qw is the w component of the rotation quaternion
  * pname:tx is the x component of the post-rotation translation
  * pname:ty is the y component of the post-rotation translation
  * pname:tz is the z component of the post-rotation translation

This transform decomposition consists of three elements.
The first is a matrix S, consisting of a scale, shear, and translation,
usually used to define the pivot point of the following rotation.
This matrix is constructed from the parameters above by:

[latexmath]
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
S =
\left(
    \begin{matrix}
        sx & a  & b  & pvx \\
        0  & sy & c  & pvy \\
        0  & 0  & sz & pvz
    \end{matrix}
\right)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

The rotation quaternion is defined as:

  {empty}:: [eq]#code:R = [ pname:qx, pname:qy, pname:qz, pname:qw ]#

This is a rotation around a conceptual normalized axis [eq]#[ ax, ay, az ]#
of amount code:theta such that:

  {empty}:: [eq]#[ pname:qx, pname:qy, pname:qz ] = sin(code:theta/2)
            {times} [ code:ax, code:ay, code:az ]#

and

  {empty}:: [eq]#pname:qw = cos(code:theta/2)#

Finally, the transform has a translation T constructed from the parameters
above by:

[latexmath]
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
T =
\left(
    \begin{matrix}
        1 & 0 & 0 & tx \\
        0 & 1 & 0 & ty \\
        0 & 0 & 1 & tz
    \end{matrix}
\right)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

The effective derived transform is then given by

  {empty}:: [eq]#code:T {times} code:R {times} code:S#

include::{generated}/validity/structs/VkSRTDataNV.txt[]
--
endif::VK_NV_ray_tracing_motion_blur[]

ifdef::VK_KHR_acceleration_structure[]
[open,refpage='VkAccelerationStructureBuildRangeInfoKHR',desc='Structure specifying build offsets and counts for acceleration structure builds',type='structs']
--
:refpage: VkAccelerationStructureBuildOffsetInfoKHR

sname:VkAccelerationStructureBuildRangeInfoKHR is defined as:

include::{generated}/api/structs/VkAccelerationStructureBuildRangeInfoKHR.txt[]

  * pname:primitiveCount defines the number of primitives for a
    corresponding acceleration structure geometry.
  * pname:primitiveOffset defines an offset in bytes into the memory where
    primitive data is defined.
  * pname:firstVertex is the index of the first vertex to build from for
    triangle geometry.
  * pname: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 elink:VkGeometryTypeKHR used:

  * For geometries of type ename:VK_GEOMETRY_TYPE_TRIANGLES_KHR,
    pname:primitiveCount is the number of triangles to be built, where each
    triangle is treated as 3 vertices.
  ** If the geometry uses indices, [eq]#pname:primitiveCount {times} 3#
     indices are consumed from
     slink:VkAccelerationStructureGeometryTrianglesDataKHR::pname:indexData,
     starting at an offset of pname:primitiveOffset.
     The value of pname:firstVertex is added to the index values before
     fetching vertices.
  ** If the geometry does not use indices, [eq]#pname:primitiveCount {times}
     3# vertices are consumed from
     slink:VkAccelerationStructureGeometryTrianglesDataKHR::pname:vertexData,
     starting at an offset of [eq]#pname:primitiveOffset {plus}
     slink:VkAccelerationStructureGeometryTrianglesDataKHR::pname:vertexStride
     {times} pname:firstVertex#.
  ** If
     slink:VkAccelerationStructureGeometryTrianglesDataKHR::pname:transformData
     is not `NULL`, a single slink:VkTransformMatrixKHR structure is
     consumed from
     slink:VkAccelerationStructureGeometryTrianglesDataKHR::pname:transformData,
     at an offset of pname:transformOffset.
     This matrix describes a transformation from the space in which the
     vertices for all triangles in this geometry are described to the space
     in which the acceleration structure is defined.
  * For geometries of type ename:VK_GEOMETRY_TYPE_AABBS_KHR,
    pname:primitiveCount is the number of axis-aligned bounding boxes.
    pname:primitiveCount slink:VkAabbPositionsKHR structures are consumed
    from slink:VkAccelerationStructureGeometryAabbsDataKHR::pname:data,
    starting at an offset of pname:primitiveOffset.
  * For geometries of type ename:VK_GEOMETRY_TYPE_INSTANCES_KHR,
    pname:primitiveCount is the number of acceleration structures.
    pname:primitiveCount slink:VkAccelerationStructureInstanceKHR
ifdef::VK_NV_ray_tracing_motion_blur[]
    or slink:VkAccelerationStructureMotionInstanceNV
endif::VK_NV_ray_tracing_motion_blur[]
    structures are consumed from
    slink:VkAccelerationStructureGeometryInstancesDataKHR::pname:data,
    starting at an offset of pname:primitiveOffset.

.Valid Usage
****
  * [[VUID-VkAccelerationStructureBuildRangeInfoKHR-primitiveOffset-03656]]
    For geometries of type ename:VK_GEOMETRY_TYPE_TRIANGLES_KHR, if the
    geometry uses indices, the offset pname:primitiveOffset from
    slink:VkAccelerationStructureGeometryTrianglesDataKHR::pname:indexData
    must: be a multiple of the element size of
    slink:VkAccelerationStructureGeometryTrianglesDataKHR::pname:indexType
  * [[VUID-VkAccelerationStructureBuildRangeInfoKHR-primitiveOffset-03657]]
    For geometries of type ename:VK_GEOMETRY_TYPE_TRIANGLES_KHR, if the
    geometry does not use indices, the offset pname:primitiveOffset from
    slink:VkAccelerationStructureGeometryTrianglesDataKHR::pname:vertexData
    must: be a multiple of the component size of
    slink:VkAccelerationStructureGeometryTrianglesDataKHR::pname:vertexFormat
  * [[VUID-VkAccelerationStructureBuildRangeInfoKHR-transformOffset-03658]]
    For geometries of type ename:VK_GEOMETRY_TYPE_TRIANGLES_KHR, the offset
    pname:transformOffset from
    slink:VkAccelerationStructureGeometryTrianglesDataKHR::pname:transformData
    must: be a multiple of 16
  * [[VUID-VkAccelerationStructureBuildRangeInfoKHR-primitiveOffset-03659]]
    For geometries of type ename:VK_GEOMETRY_TYPE_AABBS_KHR, the offset
    pname:primitiveOffset from
    slink:VkAccelerationStructureGeometryAabbsDataKHR::pname:data must: be a
    multiple of 8
  * [[VUID-VkAccelerationStructureBuildRangeInfoKHR-primitiveOffset-03660]]
    For geometries of type ename:VK_GEOMETRY_TYPE_INSTANCES_KHR, the offset
    pname:primitiveOffset from
    slink:VkAccelerationStructureGeometryInstancesDataKHR::pname:data must:
    be a multiple of 16
****

include::{generated}/validity/structs/VkAccelerationStructureBuildRangeInfoKHR.txt[]
--
endif::VK_KHR_acceleration_structure[]


[[acceleration-structure-copying]]
=== 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.

[open,refpage='vkCmdWriteAccelerationStructuresPropertiesKHR',desc='Write acceleration structure result parameters to query results.',type='protos']
--
:refpage: vkCmdWriteAccelerationStructuresPropertiesKHR

To query acceleration structure size parameters call:

ifdef::VK_KHR_acceleration_structure[]
include::{generated}/api/protos/vkCmdWriteAccelerationStructuresPropertiesKHR.txt[]
endif::VK_KHR_acceleration_structure[]

  * pname:commandBuffer is the command buffer into which the command will be
    recorded.
  * pname:accelerationStructureCount is the count of acceleration structures
    for which to query the property.
  * pname:pAccelerationStructures is a pointer to an array of existing
    previously built acceleration structures.
  * pname:queryType is a elink:VkQueryType value specifying the type of
    queries managed by the pool.
  * pname:queryPool is the query pool that will manage the results of the
    query.
  * pname:firstQuery is the first query index within the query pool that
    will contain the pname:accelerationStructureCount number of results.

Accesses to any of the acceleration structures listed in
pname:pAccelerationStructures must: be <<synchronization-dependencies,
synchronized>> with the
ename:VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_KHR
<<synchronization-pipeline-stages, pipeline stage>> and an
<<synchronization-access-types, access type>> of
ename:VK_ACCESS_ACCELERATION_STRUCTURE_READ_BIT_KHR.

  * If pname:queryType is
    ename:VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_KHR, then the
    value written out is the number of bytes required by a compacted
    acceleration structure.
  * If pname:queryType is
    ename:VK_QUERY_TYPE_ACCELERATION_STRUCTURE_SERIALIZATION_SIZE_KHR, then
    the value written out is the number of bytes required by a serialized
    acceleration structure.

.Valid Usage
****
  * [[VUID-vkCmdWriteAccelerationStructuresPropertiesKHR-queryPool-02493]]
    pname:queryPool must: have been created with a pname:queryType matching
    pname:queryType
  * [[VUID-vkCmdWriteAccelerationStructuresPropertiesKHR-queryPool-02494]]
    The queries identified by pname:queryPool and pname:firstQuery must: be
    _unavailable_
  * [[VUID-vkCmdWriteAccelerationStructuresPropertiesKHR-buffer-03736]]
    The pname:buffer used to create each acceleration structure in
    pname:pAccelerationStructures must: be bound to device memory
  * [[VUID-vkCmdWriteAccelerationStructuresPropertiesKHR-query-04880]]
    The sum of pname:query plus pname:accelerationStructureCount must: be
    less than or equal to the number of queries in pname:queryPool
include::{chapters}/commonvalidity/write_acceleration_structure_properties_common.txt[]
****

include::{generated}/validity/protos/vkCmdWriteAccelerationStructuresPropertiesKHR.txt[]
--

ifdef::VK_NV_ray_tracing[]
[open,refpage='vkCmdWriteAccelerationStructuresPropertiesNV',desc='Write acceleration structure result parameters to query results.',type='protos']
--
:refpage: vkCmdWriteAccelerationStructuresPropertiesNV

To query acceleration structure size parameters call:

include::{generated}/api/protos/vkCmdWriteAccelerationStructuresPropertiesNV.txt[]


  * pname:commandBuffer is the command buffer into which the command will be
    recorded.
  * pname:accelerationStructureCount is the count of acceleration structures
    for which to query the property.
  * pname:pAccelerationStructures is a pointer to an array of existing
    previously built acceleration structures.
  * pname:queryType is a elink:VkQueryType value specifying the type of
    queries managed by the pool.
  * pname:queryPool is the query pool that will manage the results of the
    query.
  * pname:firstQuery is the first query index within the query pool that
    will contain the pname:accelerationStructureCount number of results.

Accesses to any of the acceleration structures listed in
pname:pAccelerationStructures must: be <<synchronization-dependencies,
synchronized>> with the
ename:VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_KHR
<<synchronization-pipeline-stages, pipeline stage>> and an
<<synchronization-access-types, access type>> of
ename:VK_ACCESS_ACCELERATION_STRUCTURE_READ_BIT_KHR.

.Valid Usage
****
  * [[VUID-vkCmdWriteAccelerationStructuresPropertiesNV-queryPool-03755]]
    pname:queryPool must: have been created with a pname:queryType matching
    pname:queryType
  * [[VUID-vkCmdWriteAccelerationStructuresPropertiesNV-queryPool-03756]]
    The queries identified by pname:queryPool and pname:firstQuery must: be
    _unavailable_
  * [[VUID-vkCmdWriteAccelerationStructuresPropertiesNV-accelerationStructure-03757]]
    pname:accelerationStructure must: be bound completely and contiguously
    to a single sname:VkDeviceMemory object via
    flink:vkBindAccelerationStructureMemoryNV
  * [[VUID-vkCmdWriteAccelerationStructuresPropertiesNV-pAccelerationStructures-04958]]
    All acceleration structures in pname:pAccelerationStructures must: have
    been built prior to the execution of this command
  * [[VUID-vkCmdWriteAccelerationStructuresPropertiesNV-pAccelerationStructures-06215]]
    All acceleration structures in pname:pAccelerationStructures must: have
    been built with
    ename:VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_COMPACTION_BIT_KHR if
    pname:queryType is
    ename:VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_NV
  * [[VUID-vkCmdWriteAccelerationStructuresPropertiesNV-queryType-06216]]
    pname:queryType must: be
    ename:VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_NV
****

include::{generated}/validity/protos/vkCmdWriteAccelerationStructuresPropertiesNV.txt[]
--

[open,refpage='vkCmdCopyAccelerationStructureNV',desc='Copy an acceleration structure',type='protos']
--
:refpage: vkCmdCopyAccelerationStructureNV

To copy an acceleration structure call:

include::{generated}/api/protos/vkCmdCopyAccelerationStructureNV.txt[]

  * pname:commandBuffer is the command buffer into which the command will be
    recorded.
  * pname:dst is the target acceleration structure for the copy.
  * pname:src is the source acceleration structure for the copy.
  * pname:mode is a elink:VkCopyAccelerationStructureModeKHR value
    specifying additional operations to perform during the copy.

Accesses to pname:src and pname:dst must: be <<synchronization-dependencies,
synchronized>> with the
ename:VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_KHR
<<synchronization-pipeline-stages, pipeline stage>> and an
<<synchronization-access-types, access type>> of
ename:VK_ACCESS_ACCELERATION_STRUCTURE_READ_BIT_KHR or
ename:VK_ACCESS_ACCELERATION_STRUCTURE_WRITE_BIT_KHR as appropriate.

.Valid Usage
****
include::{chapters}/commonvalidity/copy_acceleration_structure_common.txt[]
****

include::{generated}/validity/protos/vkCmdCopyAccelerationStructureNV.txt[]
--
endif::VK_NV_ray_tracing[]

ifdef::VK_KHR_acceleration_structure[]
[open,refpage='vkCmdCopyAccelerationStructureKHR',desc='Copy an acceleration structure',type='protos']
--
:refpage: vkCmdCopyAccelerationStructureKHR

To copy an acceleration structure call:

include::{generated}/api/protos/vkCmdCopyAccelerationStructureKHR.txt[]

  * pname:commandBuffer is the command buffer into which the command will be
    recorded.
  * pname:pInfo is a pointer to a slink:VkCopyAccelerationStructureInfoKHR
    structure defining the copy operation.

This command copies the pname:pInfo->src acceleration structure to the
pname:pInfo->dst acceleration structure in the manner specified by
pname:pInfo->mode.

Accesses to pname:pInfo->src and pname:pInfo->dst must: be
<<synchronization-dependencies, synchronized>> with the
ename:VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_KHR
<<synchronization-pipeline-stages, pipeline stage>> and an
<<synchronization-access-types, access type>> of
ename:VK_ACCESS_ACCELERATION_STRUCTURE_READ_BIT_KHR or
ename:VK_ACCESS_ACCELERATION_STRUCTURE_WRITE_BIT_KHR as appropriate.

.Valid Usage
****
  * [[VUID-vkCmdCopyAccelerationStructureKHR-buffer-03737]]
    The pname:buffer used to create pname:pInfo->src must: be bound to
    device memory
  * [[VUID-vkCmdCopyAccelerationStructureKHR-buffer-03738]]
    The pname:buffer used to create pname:pInfo->dst must: be bound to
    device memory
****

include::{generated}/validity/protos/vkCmdCopyAccelerationStructureKHR.txt[]
--

[open,refpage='VkCopyAccelerationStructureInfoKHR',desc='Parameters for copying an acceleration structure',type='structs']
--
:refpage: VkCopyAccelerationStructureInfoKHR

The sname:VkCopyAccelerationStructureInfoKHR structure is defined as:

include::{generated}/api/structs/VkCopyAccelerationStructureInfoKHR.txt[]

  * pname:sType is the type of this structure.
  * pname:pNext is `NULL` or a pointer to a structure extending this
    structure.
  * pname:src is the source acceleration structure for the copy.
  * pname:dst is the target acceleration structure for the copy.
  * pname:mode is a elink:VkCopyAccelerationStructureModeKHR value that
    specifies additional operations to perform during the copy.

.Valid Usage
****
include::{chapters}/commonvalidity/copy_acceleration_structure_common.txt[]
****

include::{generated}/validity/structs/VkCopyAccelerationStructureInfoKHR.txt[]
--
endif::VK_KHR_acceleration_structure[]

[open,refpage='VkCopyAccelerationStructureModeKHR',desc='Acceleration structure copy mode',type='enums',alias='VkCopyAccelerationStructureModeNV']
--
:refpage: VkCopyAccelerationStructureModeKHR

Possible values of pname:mode specifying additional operations to perform
during the copy, are:

include::{generated}/api/enums/VkCopyAccelerationStructureModeKHR.txt[]

ifdef::VK_NV_ray_tracing[]
or the equivalent

include::{generated}/api/enums/VkCopyAccelerationStructureModeNV.txt[]
endif::VK_NV_ray_tracing[]

  * ename:VK_COPY_ACCELERATION_STRUCTURE_MODE_CLONE_KHR creates a direct
    copy of the acceleration structure specified in pname:src into the one
    specified by pname:dst.
    The pname:dst acceleration structure must: have been created with the
    same parameters as pname:src.
    If pname:src contains references to other acceleration structures,
    pname:dst will reference the same acceleration structures.
  * ename:VK_COPY_ACCELERATION_STRUCTURE_MODE_COMPACT_KHR creates a more
    compact version of an acceleration structure pname:src into pname:dst.
    The acceleration structure pname:dst must: have been created with a size
    at least as large as that returned by
    flink:vkCmdWriteAccelerationStructuresPropertiesKHR
ifdef::VK_KHR_acceleration_structure[]
    or flink:vkWriteAccelerationStructuresPropertiesKHR
endif::VK_KHR_acceleration_structure[]
    after the build of the acceleration structure specified by pname:src.
    If pname:src contains references to other acceleration structures,
    pname:dst will reference the same acceleration structures.
  * ename:VK_COPY_ACCELERATION_STRUCTURE_MODE_SERIALIZE_KHR serializes the
    acceleration structure to a semi-opaque format which can be reloaded on
    a compatible implementation.
  * ename:VK_COPY_ACCELERATION_STRUCTURE_MODE_DESERIALIZE_KHR deserializes
    the semi-opaque serialization format in the buffer to the acceleration
    structure.
--

[open,refpage='vkCmdCopyAccelerationStructureToMemoryKHR',desc='Copy an acceleration structure to device memory',type='protos']
--
:refpage: vkCmdCopyAccelerationStructureToMemoryKHR

To copy an acceleration structure to device memory call:

include::{generated}/api/protos/vkCmdCopyAccelerationStructureToMemoryKHR.txt[]

  * pname:commandBuffer is the command buffer into which the command will be
    recorded.
  * pname:pInfo is an a pointer to a
    slink:VkCopyAccelerationStructureToMemoryInfoKHR structure defining the
    copy operation.

Accesses to pname:pInfo->src must: be <<synchronization-dependencies,
synchronized>> with the
ename:VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_KHR
<<synchronization-pipeline-stages, pipeline stage>> and an
<<synchronization-access-types, access type>> of
ename:VK_ACCESS_ACCELERATION_STRUCTURE_READ_BIT_KHR.
Accesses to the buffer indicated by pname:pInfo->dst.deviceAddress must: be
synchronized with the
ename:VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_KHR pipeline stage
and an access type of ename:VK_ACCESS_TRANSFER_WRITE_BIT.

This command produces the same results as
flink: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 flink:vkCmdCopyMemoryToAccelerationStructureKHR or
flink:vkCopyMemoryToAccelerationStructureKHR.

The defined header structure for the serialized data consists of:

  * ename:VK_UUID_SIZE bytes of data matching
    sname:VkPhysicalDeviceIDProperties::pname:driverUUID
  * ename:VK_UUID_SIZE bytes of data identifying the compatibility for
    comparison using flink:vkGetDeviceAccelerationStructureCompatibilityKHR
  * A 64-bit integer of the total size matching the value queried using
    ename:VK_QUERY_TYPE_ACCELERATION_STRUCTURE_SERIALIZATION_SIZE_KHR
  * A 64-bit integer of the deserialized size to be passed in to
    sname:VkAccelerationStructureCreateInfoKHR::pname:size
  * 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.
    For top-level acceleration structures this number is
    implementation-dependent; the number of and ordering of the handles may
    not match the instance descriptions which were used to build the
    acceleration structure.

The corresponding handles matching the values returned by
ifdef::VK_KHR_acceleration_structure[flink:vkGetAccelerationStructureDeviceAddressKHR]
ifdef::VK_KHR_acceleration_structure+VK_NV_ray_tracing[or]
ifdef::VK_NV_ray_tracing[flink: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.
The serialized data is written to the buffer (or read from the buffer)
according to the host endianness.

.Valid Usage
****
  * [[VUID-vkCmdCopyAccelerationStructureToMemoryKHR-pInfo-03739]]
    pname:pInfo->dst.deviceAddress must: be a valid device address for a
    buffer bound to device memory
  * [[VUID-vkCmdCopyAccelerationStructureToMemoryKHR-pInfo-03740]]
    pname:pInfo->dst.deviceAddress must: be aligned to `256` bytes
  * [[VUID-vkCmdCopyAccelerationStructureToMemoryKHR-pInfo-03741]]
    If the buffer pointed to by pname:pInfo->dst.deviceAddress is non-sparse
    then it must: be bound completely and contiguously to a single
    slink:VkDeviceMemory object
  * [[VUID-vkCmdCopyAccelerationStructureToMemoryKHR-None-03559]]
    The pname:buffer used to create pname:pInfo->src must: be bound to
    device memory
****

include::{generated}/validity/protos/vkCmdCopyAccelerationStructureToMemoryKHR.txt[]
--

[open,refpage='VkCopyAccelerationStructureToMemoryInfoKHR',desc='Parameters for serializing an acceleration structure',type='structs']
--
:refpage: VkCopyAccelerationStructureToMemoryInfoKHR

include::{generated}/api/structs/VkCopyAccelerationStructureToMemoryInfoKHR.txt[]

  * pname:sType is the type of this structure.
  * pname:pNext is `NULL` or a pointer to a structure extending this
    structure.
  * pname:src is the source acceleration structure for the copy
  * pname:dst is the device or host address to memory which is the target
    for the copy
  * pname:mode is a elink:VkCopyAccelerationStructureModeKHR value that
    specifies additional operations to perform during the copy.

.Valid Usage
****
  * [[VUID-VkCopyAccelerationStructureToMemoryInfoKHR-src-04959]]
    The source acceleration structure pname:src must: have been constructed
    prior to the execution of this command
  * [[VUID-VkCopyAccelerationStructureToMemoryInfoKHR-dst-03561]]
    The memory pointed to by pname:dst must: be at least as large as the
    serialization size of pname:src, as reported by
    flink:vkWriteAccelerationStructuresPropertiesKHR or
    flink:vkCmdWriteAccelerationStructuresPropertiesKHR with a query type of
    ename:VK_QUERY_TYPE_ACCELERATION_STRUCTURE_SERIALIZATION_SIZE_KHR
  * [[VUID-VkCopyAccelerationStructureToMemoryInfoKHR-mode-03412]]
    pname:mode must: be
    ename:VK_COPY_ACCELERATION_STRUCTURE_MODE_SERIALIZE_KHR
****

include::{generated}/validity/structs/VkCopyAccelerationStructureToMemoryInfoKHR.txt[]
--

[open,refpage='vkCmdCopyMemoryToAccelerationStructureKHR',desc='Copy device memory to an acceleration structure',type='protos']
--
:refpage: vkCmdCopyMemoryToAccelerationStructureKHR

To copy device memory to an acceleration structure call:

include::{generated}/api/protos/vkCmdCopyMemoryToAccelerationStructureKHR.txt[]

  * pname:commandBuffer is the command buffer into which the command will be
    recorded.
  * pname:pInfo is a pointer to a
    slink:VkCopyMemoryToAccelerationStructureInfoKHR structure defining the
    copy operation.

Accesses to pname:pInfo->dst must: be <<synchronization-dependencies,
synchronized>> with the
ename:VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_KHR
<<synchronization-pipeline-stages, pipeline stage>> and an
<<synchronization-access-types, access type>> of
ename:VK_ACCESS_ACCELERATION_STRUCTURE_WRITE_BIT_KHR.
Accesses to the buffer indicated by pname:pInfo->src.deviceAddress must: be
synchronized with the
ename:VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_KHR pipeline stage
and an access type of ename:VK_ACCESS_TRANSFER_READ_BIT.

This command can accept acceleration structures produced by either
flink:vkCmdCopyAccelerationStructureToMemoryKHR or
flink:vkCopyAccelerationStructureToMemoryKHR.

The structure provided as input to deserialize is as described in
flink: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
****
  * [[VUID-vkCmdCopyMemoryToAccelerationStructureKHR-pInfo-03742]]
    pname:pInfo->src.deviceAddress must: be a valid device address for a
    buffer bound to device memory
  * [[VUID-vkCmdCopyMemoryToAccelerationStructureKHR-pInfo-03743]]
    pname:pInfo->src.deviceAddress must: be aligned to `256` bytes
  * [[VUID-vkCmdCopyMemoryToAccelerationStructureKHR-pInfo-03744]]
    If the buffer pointed to by pname:pInfo->src.deviceAddress is non-sparse
    then it must: be bound completely and contiguously to a single
    slink:VkDeviceMemory object
  * [[VUID-vkCmdCopyMemoryToAccelerationStructureKHR-buffer-03745]]
    The pname:buffer used to create pname:pInfo->dst must: be bound to
    device memory
****

include::{generated}/validity/protos/vkCmdCopyMemoryToAccelerationStructureKHR.txt[]
--

[open,refpage='VkCopyMemoryToAccelerationStructureInfoKHR',desc='Parameters for deserializing an acceleration structure',type='structs']
--
:refpage: VkCopyMemoryToAccelerationStructureInfoKHR

The sname:VkCopyMemoryToAccelerationStructureInfoKHR structure is defined
as:

include::{generated}/api/structs/VkCopyMemoryToAccelerationStructureInfoKHR.txt[]

  * pname:sType is the type of this structure.
  * pname:pNext is `NULL` or a pointer to a structure extending this
    structure.
  * pname:src is the device or host address to memory containing the source
    data for the copy.
  * pname:dst is the target acceleration structure for the copy.
  * pname:mode is a elink:VkCopyAccelerationStructureModeKHR value that
    specifies additional operations to perform during the copy.

.Valid Usage
****
  * [[VUID-VkCopyMemoryToAccelerationStructureInfoKHR-src-04960]]
    The source memory pointed to by pname:src must: contain data previously
    serialized using flink:vkCmdCopyAccelerationStructureToMemoryKHR,
    potentially modified to relocate acceleration structure references as
    described in that command
  * [[VUID-VkCopyMemoryToAccelerationStructureInfoKHR-mode-03413]]
    pname:mode must: be
    ename:VK_COPY_ACCELERATION_STRUCTURE_MODE_DESERIALIZE_KHR
  * [[VUID-VkCopyMemoryToAccelerationStructureInfoKHR-pInfo-03414]]
    The data in pname:src must: have a format compatible with the
    destination physical device as returned by
    flink:vkGetDeviceAccelerationStructureCompatibilityKHR
  * [[VUID-VkCopyMemoryToAccelerationStructureInfoKHR-dst-03746]]
    pname:dst must: have been created with a pname:size greater than or
    equal to that used to serialize the data in pname:src
****

include::{generated}/validity/structs/VkCopyMemoryToAccelerationStructureInfoKHR.txt[]
--

[open,refpage='vkGetDeviceAccelerationStructureCompatibilityKHR',desc='Check if a serialized acceleration structure is compatible with the current device',type='protos']
--
:refpage: vkGetDeviceAccelerationStructureCompatibilityKHR

To check if a serialized acceleration structure is compatible with the
current device call:

include::{generated}/api/protos/vkGetDeviceAccelerationStructureCompatibilityKHR.txt[]

  * pname:device is the device to check the version against.
  * pname:pVersionInfo is a pointer to a
    slink:VkAccelerationStructureVersionInfoKHR structure specifying version
    information to check against the device.
  * pname:pCompatibility is a pointer to a
    elink:VkAccelerationStructureCompatibilityKHR value in which
    compatibility information is returned.

.Valid Usage
****
// TBD
  * [[VUID-vkGetDeviceAccelerationStructureCompatibilityKHR-rayTracingPipeline-03661]]
    The <<features-rayTracingPipeline, pname:rayTracingPipeline>> or
    <<features-rayQuery, pname:rayQuery>> feature must: be enabled
****

include::{generated}/validity/protos/vkGetDeviceAccelerationStructureCompatibilityKHR.txt[]
--

[open,refpage='VkAccelerationStructureVersionInfoKHR',desc='Acceleration structure version information',type='structs']
--
:refpage: VkAccelerationStructureVersionKHR

The sname:VkAccelerationStructureVersionInfoKHR structure is defined as:

include::{generated}/api/structs/VkAccelerationStructureVersionInfoKHR.txt[]

  * pname:sType is the type of this structure.
  * pname:pNext is `NULL` or a pointer to a structure extending this
    structure.
  * pname:pVersionData is a pointer to the version header of an acceleration
    structure as defined in flink:vkCmdCopyAccelerationStructureToMemoryKHR

[NOTE]
.Note
====
pname:pVersionData is a _pointer_ to an array of 2*ename:VK_UUID_SIZE
code:uint8_t values instead of two ename:VK_UUID_SIZE arrays as the expected
use case for this member is to be pointed at the header of an previously
serialized acceleration structure (via
flink:vkCmdCopyAccelerationStructureToMemoryKHR or
flink:vkCopyAccelerationStructureToMemoryKHR) that is loaded in memory.
Using arrays would necessitate extra memory copies of the UUIDs.
====

include::{generated}/validity/structs/VkAccelerationStructureVersionInfoKHR.txt[]
--

[open,refpage='VkAccelerationStructureCompatibilityKHR',desc='Acceleration structure compatibility',type='enums']
--
Possible values of pname:pCompatibility returned by
flink:vkGetDeviceAccelerationStructureCompatibilityKHR are:

include::{generated}/api/enums/VkAccelerationStructureCompatibilityKHR.txt[]

  * ename:VK_ACCELERATION_STRUCTURE_COMPATIBILITY_COMPATIBLE_KHR if the
    pname:pVersionData version acceleration structure is compatible with
    pname:device.
  * ename:VK_ACCELERATION_STRUCTURE_COMPATIBILITY_INCOMPATIBLE_KHR if the
    pname:pVersionData version acceleration structure is not compatible with
    pname:device.
--


[[host-acceleration-structure]]
== Host Acceleration Structure Operations

Implementations are also required to provide host implementations of the
acceleration structure operations if the
<<features-accelerationStructureHostCommands,pname:accelerationStructureHostCommands>>
feature is enabled:

  * flink:vkBuildAccelerationStructuresKHR corresponding to
    flink:vkCmdBuildAccelerationStructuresKHR
  * flink:vkCopyAccelerationStructureKHR corresponding to
    flink:vkCmdCopyAccelerationStructureKHR
  * flink:vkCopyAccelerationStructureToMemoryKHR corresponding to
    flink:vkCmdCopyAccelerationStructureToMemoryKHR
  * flink:vkCopyMemoryToAccelerationStructureKHR corresponding to
    flink:vkCmdCopyMemoryToAccelerationStructureKHR
  * flink:vkWriteAccelerationStructuresPropertiesKHR corresponding to
    flink: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]
.Note
====
The flink:vkBuildAccelerationStructuresKHR and
flink:vkCmdBuildAccelerationStructuresKHR 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 flink:vkBuildAccelerationStructuresKHR
to build a structure, compact it on the device using
flink:vkCmdCopyAccelerationStructureKHR, and serialize the result using
flink:vkCopyAccelerationStructureToMemoryKHR.
====

[NOTE]
.Note
====
For efficient execution, acceleration structures manipulated using these
commands should always be bound to host cached memory, as the implementation
may need to repeatedly read and write this memory during the execution of
the command.
====

[open,refpage='vkBuildAccelerationStructuresKHR',desc='Build an acceleration structure on the host',type='protos']
--
:refpage: vkBuildAccelerationStructuresKHR
:maxinstancecheck: pname:ppBuildRangeInfos[i][j].pname:primitiveCount

To build acceleration structures on the host, call:

include::{generated}/api/protos/vkBuildAccelerationStructuresKHR.txt[]

  * pname:device is the sname:VkDevice for which the acceleration structures
    are being built.
  * pname:deferredOperation is an optional slink:VkDeferredOperationKHR to
    <<deferred-host-operations-requesting, request deferral>> for this
    command.
  * pname:infoCount is the number of acceleration structures to build.
    It specifies the number of the pname:pInfos structures and
    pname:ppBuildRangeInfos pointers that must: be provided.
  * pname:pInfos is a pointer to an array of pname:infoCount
    slink:VkAccelerationStructureBuildGeometryInfoKHR structures defining
    the geometry used to build each acceleration structure.
  * pname:ppBuildRangeInfos is a pointer to an array of pname:infoCount
    pointers to arrays of slink:VkAccelerationStructureBuildRangeInfoKHR
    structures.
    Each pname:ppBuildRangeInfos[i] is a pointer to an array of
    pname:pInfos[i].pname:geometryCount
    slink:VkAccelerationStructureBuildRangeInfoKHR structures defining
    dynamic offsets to the addresses where geometry data is stored, as
    defined by pname:pInfos[i].

This command fulfills the same task as
flink:vkCmdBuildAccelerationStructuresKHR but is executed by the host.

The fname:vkBuildAccelerationStructuresKHR 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]
.Note
====
This means that an application cannot: build a top-level acceleration
structure in the same flink:vkBuildAccelerationStructuresKHR 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
****
include::{chapters}/commonvalidity/build_acceleration_structure_common.txt[]
include::{chapters}/commonvalidity/build_acceleration_structure_nonindirect_common.txt[]
include::{chapters}/commonvalidity/deferred_operations_common.txt[]
  * [[VUID-vkBuildAccelerationStructuresKHR-pInfos-03722]]
    For each element of pname:pInfos, the pname:buffer used to create its
    pname:dstAccelerationStructure member must: be bound to host-visible
    device memory
  * [[VUID-vkBuildAccelerationStructuresKHR-pInfos-03723]]
    For each element of pname:pInfos, if its pname:mode member is
    ename:VK_BUILD_ACCELERATION_STRUCTURE_MODE_UPDATE_KHR the pname:buffer
    used to create its pname:srcAccelerationStructure member must: be bound
    to host-visible device memory
  * [[VUID-vkBuildAccelerationStructuresKHR-pInfos-03724]]
    For each element of pname:pInfos, the pname:buffer used to create each
    acceleration structure referenced by the pname:geometry.instances.data
    member of any element of pname:pGeometries or pname:ppGeometries with a
    pname:geometryType of ename:VK_GEOMETRY_TYPE_INSTANCES_KHR must: be
    bound to host-visible device memory
  * [[VUID-vkBuildAccelerationStructuresKHR-accelerationStructureHostCommands-03581]]
    The <<features-accelerationStructureHostCommands,
    sname:VkPhysicalDeviceAccelerationStructureFeaturesKHR::pname:accelerationStructureHostCommands>>
    feature must: be enabled
  * [[VUID-vkBuildAccelerationStructuresKHR-pInfos-03725]]
    If pname:pInfos[i].pname:mode is
    ename:VK_BUILD_ACCELERATION_STRUCTURE_MODE_BUILD_KHR, all addresses
    between pname:pInfos[i].pname:scratchData.hostAddress and
    pname:pInfos[i].pname:scratchData.hostAddress + N - 1 must: be valid
    host memory, where N is given by the pname:buildScratchSize member of
    the slink:VkAccelerationStructureBuildSizesInfoKHR structure returned
    from a call to flink:vkGetAccelerationStructureBuildSizesKHR with an
    identical slink:VkAccelerationStructureBuildGeometryInfoKHR structure
    and primitive count
  * [[VUID-vkBuildAccelerationStructuresKHR-pInfos-03726]]
    If pname:pInfos[i].pname:mode is
    ename:VK_BUILD_ACCELERATION_STRUCTURE_MODE_UPDATE_KHR, all addresses
    between pname:pInfos[i].pname:scratchData.hostAddress and
    pname:pInfos[i].pname:scratchData.hostAddress + N - 1 must: be valid
    host memory, where N is given by the pname:updateScratchSize member of
    the slink:VkAccelerationStructureBuildSizesInfoKHR structure returned
    from a call to flink:vkGetAccelerationStructureBuildSizesKHR with an
    identical slink:VkAccelerationStructureBuildGeometryInfoKHR structure
    and primitive count
  * [[VUID-vkBuildAccelerationStructuresKHR-pInfos-03771]]
    For any element of pname:pInfos[i].pname:pGeometries or
    pname:pInfos[i].pname:ppGeometries with a pname:geometryType of
    ename:VK_GEOMETRY_TYPE_TRIANGLES_KHR,
    pname:geometry.triangles.vertexData.hostAddress must: be a valid host
    address
  * [[VUID-vkBuildAccelerationStructuresKHR-pInfos-03772]]
    For any element of pname:pInfos[i].pname:pGeometries or
    pname:pInfos[i].pname:ppGeometries with a pname:geometryType of
    ename:VK_GEOMETRY_TYPE_TRIANGLES_KHR, if
    pname:geometry.triangles.indexType is not ename:VK_INDEX_TYPE_NONE_KHR,
    pname:geometry.triangles.indexData.hostAddress must: be a valid host
    address
  * [[VUID-vkBuildAccelerationStructuresKHR-pInfos-03773]]
    For any element of pname:pInfos[i].pname:pGeometries or
    pname:pInfos[i].pname:ppGeometries with a pname:geometryType of
    ename:VK_GEOMETRY_TYPE_TRIANGLES_KHR, if
    pname:geometry.triangles.transformData.hostAddress is not `0`, it must:
    be a valid host address
  * [[VUID-vkBuildAccelerationStructuresKHR-pInfos-03774]]
    For any element of pname:pInfos[i].pname:pGeometries or
    pname:pInfos[i].pname:ppGeometries with a pname:geometryType of
    ename:VK_GEOMETRY_TYPE_AABBS_KHR, pname:geometry.aabbs.data.hostAddress
    must: be a valid host address
ifdef::VK_KHR_device_group,VK_VERSION_1_1[]
  * [[VUID-vkBuildAccelerationStructuresKHR-pInfos-03775]]
    For each element of pname:pInfos, the pname:buffer used to create its
    pname:dstAccelerationStructure member must: be bound to memory that was
    not allocated with multiple instances
  * [[VUID-vkBuildAccelerationStructuresKHR-pInfos-03776]]
    For each element of pname:pInfos, if its pname:mode member is
    ename:VK_BUILD_ACCELERATION_STRUCTURE_MODE_UPDATE_KHR the pname:buffer
    used to create its pname:srcAccelerationStructure member must: be bound
    to memory that was not allocated with multiple instances
  * [[VUID-vkBuildAccelerationStructuresKHR-pInfos-03777]]
    For each element of pname:pInfos, the pname:buffer used to create each
    acceleration structure referenced by the pname:geometry.instances.data
    member of any element of pname:pGeometries or pname:ppGeometries with a
    pname:geometryType of ename:VK_GEOMETRY_TYPE_INSTANCES_KHR must: be
    bound to memory that was not allocated with multiple instances
endif::VK_KHR_device_group,VK_VERSION_1_1[]
  * [[VUID-vkBuildAccelerationStructuresKHR-pInfos-03778]]
    For any element of pname:pInfos[i].pname:pGeometries or
    pname:pInfos[i].pname:ppGeometries with a pname:geometryType of
    ename:VK_GEOMETRY_TYPE_INSTANCES_KHR,
    pname:geometry.instances.data.hostAddress must: be a valid host address
  * [[VUID-vkBuildAccelerationStructuresKHR-pInfos-03779]]
    For any element of pname:pInfos[i].pname:pGeometries or
    pname:pInfos[i].pname:ppGeometries with a pname:geometryType of
    ename:VK_GEOMETRY_TYPE_INSTANCES_KHR, each
    slink:VkAccelerationStructureInstanceKHR::pname:accelerationStructureReference
    value in pname:geometry.instances.data.hostAddress must be a valid
    slink:VkAccelerationStructureKHR object
ifdef::VK_NV_ray_tracing_motion_blur[]
  * [[VUID-vkBuildAccelerationStructuresKHR-pInfos-04930]]
    For any element of pname:pInfos[i].pname:pGeometries or
    pname:pInfos[i].pname:ppGeometries with a pname:geometryType of
    ename:VK_GEOMETRY_TYPE_INSTANCES_KHR with
    ename:VK_BUILD_ACCELERATION_STRUCTURE_MOTION_BIT_NV set, each
    pname:accelerationStructureReference in any structure in
    slink:VkAccelerationStructureMotionInstanceNV value in
    pname:geometry.instances.data.hostAddress must be a valid
    slink:VkAccelerationStructureKHR object
endif::VK_NV_ray_tracing_motion_blur[]
****

include::{generated}/validity/protos/vkBuildAccelerationStructuresKHR.txt[]
--

[open,refpage='vkCopyAccelerationStructureKHR',desc='Copy an acceleration structure on the host',type='protos']
--
:refpage: vkCopyAccelerationStructureKHR

To copy or compact an acceleration structure on the host, call:

include::{generated}/api/protos/vkCopyAccelerationStructureKHR.txt[]

  * pname:device is the device which owns the acceleration structures.
  * pname:deferredOperation is an optional slink:VkDeferredOperationKHR to
    <<deferred-host-operations-requesting, request deferral>> for this
    command.
  * pname:pInfo is a pointer to a slink:VkCopyAccelerationStructureInfoKHR
    structure defining the copy operation.

This command fulfills the same task as
flink:vkCmdCopyAccelerationStructureKHR but is executed by the host.

.Valid Usage
****
include::{chapters}/commonvalidity/deferred_operations_common.txt[]
  * [[VUID-vkCopyAccelerationStructureKHR-buffer-03727]]
    The pname:buffer used to create pname:pInfo->src must: be bound to
    host-visible device memory
  * [[VUID-vkCopyAccelerationStructureKHR-buffer-03728]]
    The pname:buffer used to create pname:pInfo->dst must: be bound to
    host-visible device memory
  * [[VUID-vkCopyAccelerationStructureKHR-accelerationStructureHostCommands-03582]]
    The <<features-accelerationStructureHostCommands,
    sname:VkPhysicalDeviceAccelerationStructureFeaturesKHR::pname:accelerationStructureHostCommands>>
    feature must: be enabled
ifdef::VK_KHR_device_group,VK_VERSION_1_1[]
  * [[VUID-vkCopyAccelerationStructureKHR-buffer-03780]]
    The pname:buffer used to create pname:pInfo->src must: be bound to
    memory that was not allocated with multiple instances
  * [[VUID-vkCopyAccelerationStructureKHR-buffer-03781]]
    The pname:buffer used to create pname:pInfo->dst must: be bound to
    memory that was not allocated with multiple instances
endif::VK_KHR_device_group,VK_VERSION_1_1[]
****

include::{generated}/validity/protos/vkCopyAccelerationStructureKHR.txt[]
--

[open,refpage='vkCopyMemoryToAccelerationStructureKHR',desc='Deserialize an acceleration structure on the host',type='protos']
--
:refpage: vkCopyMemoryToAccelerationStructureKHR

To copy host accessible memory to an acceleration structure, call:

include::{generated}/api/protos/vkCopyMemoryToAccelerationStructureKHR.txt[]

  * pname:device is the device which owns pname:pInfo->dst.
  * pname:deferredOperation is an optional slink:VkDeferredOperationKHR to
    <<deferred-host-operations-requesting, request deferral>> for this
    command.
  * pname:pInfo is a pointer to a
    slink:VkCopyMemoryToAccelerationStructureInfoKHR structure defining the
    copy operation.

This command fulfills the same task as
flink:vkCmdCopyMemoryToAccelerationStructureKHR but is executed by the host.

This command can accept acceleration structures produced by either
flink:vkCmdCopyAccelerationStructureToMemoryKHR or
flink:vkCopyAccelerationStructureToMemoryKHR.

.Valid Usage
****
include::{chapters}/commonvalidity/deferred_operations_common.txt[]
  * [[VUID-vkCopyMemoryToAccelerationStructureKHR-pInfo-03729]]
    pname:pInfo->src.hostAddress must: be a valid host pointer
  * [[VUID-vkCopyMemoryToAccelerationStructureKHR-pInfo-03750]]
    pname:pInfo->src.hostAddress must: be aligned to 16 bytes
  * [[VUID-vkCopyMemoryToAccelerationStructureKHR-buffer-03730]]
    The pname:buffer used to create pname:pInfo->dst must: be bound to
    host-visible device memory
  * [[VUID-vkCopyMemoryToAccelerationStructureKHR-accelerationStructureHostCommands-03583]]
    The <<features-accelerationStructureHostCommands,
    sname:VkPhysicalDeviceAccelerationStructureFeaturesKHR::pname:accelerationStructureHostCommands>>
    feature must: be enabled
ifdef::VK_KHR_device_group,VK_VERSION_1_1[]
  * [[VUID-vkCopyMemoryToAccelerationStructureKHR-buffer-03782]]
    The pname:buffer used to create pname:pInfo->dst must: be bound to
    memory that was not allocated with multiple instances
endif::VK_KHR_device_group,VK_VERSION_1_1[]
****

include::{generated}/validity/protos/vkCopyMemoryToAccelerationStructureKHR.txt[]
--

[open,refpage='vkCopyAccelerationStructureToMemoryKHR',desc='Serialize an acceleration structure on the host',type='protos']
--
:refpage: vkCopyAccelerationStructureToMemoryKHR

To copy an acceleration structure to host accessible memory, call:

include::{generated}/api/protos/vkCopyAccelerationStructureToMemoryKHR.txt[]

  * pname:device is the device which owns pname:pInfo->src.
  * pname:deferredOperation is an optional slink:VkDeferredOperationKHR to
    <<deferred-host-operations-requesting, request deferral>> for this
    command.
  * pname:pInfo is a pointer to a
    slink:VkCopyAccelerationStructureToMemoryInfoKHR structure defining the
    copy operation.

This command fulfills the same task as
flink:vkCmdCopyAccelerationStructureToMemoryKHR but is executed by the host.

This command produces the same results as
flink: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 flink:vkCmdCopyMemoryToAccelerationStructureKHR or
flink:vkCopyMemoryToAccelerationStructureKHR.

.Valid Usage
****
include::{chapters}/commonvalidity/deferred_operations_common.txt[]
  * [[VUID-vkCopyAccelerationStructureToMemoryKHR-buffer-03731]]
    The pname:buffer used to create pname:pInfo->src must: be bound to
    host-visible device memory
  * [[VUID-vkCopyAccelerationStructureToMemoryKHR-pInfo-03732]]
    pname:pInfo->dst.hostAddress must: be a valid host pointer
  * [[VUID-vkCopyAccelerationStructureToMemoryKHR-pInfo-03751]]
    pname:pInfo->dst.hostAddress must: be aligned to 16 bytes
  * [[VUID-vkCopyAccelerationStructureToMemoryKHR-accelerationStructureHostCommands-03584]]
    The <<features-accelerationStructureHostCommands,
    sname:VkPhysicalDeviceAccelerationStructureFeaturesKHR::pname:accelerationStructureHostCommands>>
    feature must: be enabled
ifdef::VK_KHR_device_group,VK_VERSION_1_1[]
  * [[VUID-vkCopyAccelerationStructureToMemoryKHR-buffer-03783]]
    The pname:buffer used to create pname:pInfo->src must: be bound to
    memory that was not allocated with multiple instances
endif::VK_KHR_device_group,VK_VERSION_1_1[]
****

include::{generated}/validity/protos/vkCopyAccelerationStructureToMemoryKHR.txt[]
--

[open,refpage='vkWriteAccelerationStructuresPropertiesKHR',desc='Query acceleration structure meta-data on the host',type='protos']
--
:refpage: vkWriteAccelerationStructuresPropertiesKHR

To query acceleration structure size parameters on the host, call:

include::{generated}/api/protos/vkWriteAccelerationStructuresPropertiesKHR.txt[]

  * pname:device is the device which owns the acceleration structures in
    pname:pAccelerationStructures.
  * pname:accelerationStructureCount is the count of acceleration structures
    for which to query the property.
  * pname:pAccelerationStructures is a pointer to an array of existing
    previously built acceleration structures.
  * pname:queryType is a elink:VkQueryType value specifying the property to
    be queried.
  * pname:dataSize is the size in bytes of the buffer pointed to by
    pname:pData.
  * pname:pData is a pointer to a user-allocated buffer where the results
    will be written.
  * pname:stride is the stride in bytes between results for individual
    queries within pname:pData.

This command fulfills the same task as
flink:vkCmdWriteAccelerationStructuresPropertiesKHR but is executed by the
host.

.Valid Usage
****
include::{chapters}/commonvalidity/write_acceleration_structure_properties_common.txt[]
  * [[VUID-vkWriteAccelerationStructuresPropertiesKHR-queryType-03448]]
    If pname:queryType is
    ename:VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_KHR, then
    pname:stride must: be a multiple of the size of basetype:VkDeviceSize
  * [[VUID-vkWriteAccelerationStructuresPropertiesKHR-queryType-03449]]
    If pname:queryType is
    ename:VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_KHR, then
    pname:data must: point to a basetype:VkDeviceSize
  * [[VUID-vkWriteAccelerationStructuresPropertiesKHR-queryType-03450]]
    If pname:queryType is
    ename:VK_QUERY_TYPE_ACCELERATION_STRUCTURE_SERIALIZATION_SIZE_KHR, then
    pname:stride must: be a multiple of the size of basetype:VkDeviceSize
  * [[VUID-vkWriteAccelerationStructuresPropertiesKHR-queryType-03451]]
    If pname:queryType is
    ename:VK_QUERY_TYPE_ACCELERATION_STRUCTURE_SERIALIZATION_SIZE_KHR, then
    pname:data must: point to a basetype:VkDeviceSize
  * [[VUID-vkWriteAccelerationStructuresPropertiesKHR-dataSize-03452]]
    pname:dataSize must: be greater than or equal to
    [eq]#pname:accelerationStructureCount*pname:stride#
  * [[VUID-vkWriteAccelerationStructuresPropertiesKHR-buffer-03733]]
    The pname:buffer used to create each acceleration structure in
    pname:pAccelerationStructures must: be bound to host-visible device
    memory
  * [[VUID-vkWriteAccelerationStructuresPropertiesKHR-accelerationStructureHostCommands-03585]]
    The <<features-accelerationStructureHostCommands,
    sname:VkPhysicalDeviceAccelerationStructureFeaturesKHR::pname:accelerationStructureHostCommands>>
    feature must: be enabled
ifdef::VK_KHR_device_group,VK_VERSION_1_1[]
  * [[VUID-vkWriteAccelerationStructuresPropertiesKHR-buffer-03784]]
    The pname:buffer used to create each acceleration structure in
    pname:pAccelerationStructures must: be bound to memory that was not
    allocated with multiple instances
endif::VK_KHR_device_group,VK_VERSION_1_1[]
****

include::{generated}/validity/protos/vkWriteAccelerationStructuresPropertiesKHR.txt[]
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