// This section is included inside the Resource Descriptors chapter (descriptorsets.txt)

[[descriptorsets-accelerationstructure]]
=== Acceleration Structure

An _acceleration structure_
(ename:VK_DESCRIPTOR_TYPE_ACCELERATION_STRUCTURE_NV) is a descriptor type
that is used to retrieve scene geometry from within shaders bound to ray
tracing pipelines.
Shaders have read-only access to the memory.

[open,refpage='VkWriteDescriptorSetAccelerationStructureNV',desc='Structure specifying acceleration to query for memory requirements',type='structs']
--
The sname:VkWriteDescriptorSetAccelerationStructureNV structure is defined
as:

include::../../api/structs/VkWriteDescriptorSetAccelerationStructureNV.txt[]

  * pname:sType is the type of this structure.
  * pname:pNext is `NULL` or a pointer to an extension-specific structure.
  * pname:accelerationStructureCount is the number of elements in
    pname:pAccelerationStructures.
  * pname:pAccelerationStructures are the acceleration structures to update.

.Valid Usage
****
  * [[VUID-VkWriteDescriptorSetAccelerationStructureNV-accelerationStructureCount-02236]]
    pname:accelerationStructureCount must: be equal to pname:descriptorCount
    in the extended structure
****

include::../../validity/structs/VkWriteDescriptorSetAccelerationStructureNV.txt[]
--