# vkCmdWriteAccelerationStructuresPropertiesNV(3) Manual Page

## Name

vkCmdWriteAccelerationStructuresPropertiesNV - Write acceleration structure result parameters to query results.

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## C Specification

To query acceleration structure size parameters call:

    // Provided by VK_NV_ray_tracing
    void vkCmdWriteAccelerationStructuresPropertiesNV(
        VkCommandBuffer                             commandBuffer,
        uint32_t                                    accelerationStructureCount,
        const VkAccelerationStructureNV*            pAccelerationStructures,
        VkQueryType                                 queryType,
        VkQueryPool                                 queryPool,
        uint32_t                                    firstQuery);

## Parameters

- `commandBuffer` is the command buffer into which the command will be recorded.

- `accelerationStructureCount` is the count of acceleration structures for which to query the property.

- `pAccelerationStructures` is a pointer to an array of existing previously built acceleration structures.

- `queryType` is a VkQueryType value specifying the type of queries managed by the pool.

- `queryPool` is the query pool that will manage the results of the query.

- `firstQuery` is the first query index within the query pool that will contain the `accelerationStructureCount` number of results.

## Description

Accesses to any of the acceleration structures listed in `pAccelerationStructures` must be synchronized with the `VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_KHR` pipeline stage and an access type of `VK_ACCESS_ACCELERATION_STRUCTURE_READ_BIT_KHR`.

Valid Usage

- VUID-vkCmdWriteAccelerationStructuresPropertiesNV-queryPool-03755
  `queryPool` must have been created with a `queryType` matching `queryType`

- VUID-vkCmdWriteAccelerationStructuresPropertiesNV-queryPool-03756
  The queries identified by `queryPool` and `firstQuery` must be unavailable

- VUID-vkCmdWriteAccelerationStructuresPropertiesNV-accelerationStructure-03757
  `accelerationStructure` must be bound completely and contiguously to a single `VkDeviceMemory` object via vkBindAccelerationStructureMemoryNV

- VUID-vkCmdWriteAccelerationStructuresPropertiesNV-pAccelerationStructures-04958
  All acceleration structures in `pAccelerationStructures` must have been built prior to the execution of this command

- VUID-vkCmdWriteAccelerationStructuresPropertiesNV-pAccelerationStructures-06215
  All acceleration structures in `pAccelerationStructures` must have been built with `VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_COMPACTION_BIT_KHR` if `queryType` is `VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_NV`

- VUID-vkCmdWriteAccelerationStructuresPropertiesNV-queryType-06216
  `queryType` must be `VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_NV`

Valid Usage (Implicit)

- VUID-vkCmdWriteAccelerationStructuresPropertiesNV-commandBuffer-parameter
  `commandBuffer` must be a valid VkCommandBuffer handle

- VUID-vkCmdWriteAccelerationStructuresPropertiesNV-pAccelerationStructures-parameter
  `pAccelerationStructures` must be a valid pointer to an array of `accelerationStructureCount` valid VkAccelerationStructureNV handles

- VUID-vkCmdWriteAccelerationStructuresPropertiesNV-queryType-parameter
  `queryType` must be a valid VkQueryType value

- VUID-vkCmdWriteAccelerationStructuresPropertiesNV-queryPool-parameter
  `queryPool` must be a valid VkQueryPool handle

- VUID-vkCmdWriteAccelerationStructuresPropertiesNV-commandBuffer-recording
  `commandBuffer` must be in the recording state

- VUID-vkCmdWriteAccelerationStructuresPropertiesNV-commandBuffer-cmdpool
  The `VkCommandPool` that `commandBuffer` was allocated from must support compute operations

- VUID-vkCmdWriteAccelerationStructuresPropertiesNV-renderpass
  This command must only be called outside of a render pass instance

- VUID-vkCmdWriteAccelerationStructuresPropertiesNV-videocoding
  This command must only be called outside of a video coding scope

- VUID-vkCmdWriteAccelerationStructuresPropertiesNV-accelerationStructureCount-arraylength
  `accelerationStructureCount` must be greater than `0`

- VUID-vkCmdWriteAccelerationStructuresPropertiesNV-commonparent
  Each of `commandBuffer`, `queryPool`, and the elements of `pAccelerationStructures` must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization

- Host access to `commandBuffer` must be externally synchronized

- Host access to the `VkCommandPool` that `commandBuffer` was allocated from must be externally synchronized

Command Properties

Command Buffer Levels | Render Pass Scope | Video Coding Scope | Supported Queue Types | Command Type
--- | --- | --- | --- | ---
Primary Secondary | Outside | Outside | Compute | Action

## See Also

VK_NV_ray_tracing, VkAccelerationStructureNV, VkCommandBuffer, VkQueryPool, VkQueryType

## Document Notes

For more information, see the Vulkan Specification

This page is extracted from the Vulkan Specification. Fixes and changes should be made to the Specification, not directly.

## Copyright

Copyright 2014-2024 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0