# vkWriteMicromapsPropertiesEXT(3) Manual Page

## Name

vkWriteMicromapsPropertiesEXT - Query micromap meta-data on the host

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## C Specification

To query micromap size parameters on the host, call:

    // Provided by VK_EXT_opacity_micromap
    VkResult vkWriteMicromapsPropertiesEXT(
        VkDevice                                    device,
        uint32_t                                    micromapCount,
        const VkMicromapEXT*                        pMicromaps,
        VkQueryType                                 queryType,
        size_t                                      dataSize,
        void*                                       pData,
        size_t                                      stride);

## Parameters

- `device` is the device which owns the micromaps in `pMicromaps`.

- `micromapCount` is the count of micromaps for which to query the property.

- `pMicromaps` is a pointer to an array of existing previously built micromaps.

- `queryType` is a VkQueryType value specifying the property to be queried.

- `dataSize` is the size in bytes of the buffer pointed to by `pData`.

- `pData` is a pointer to an application-allocated buffer where the results will be written.

- `stride` is the stride in bytes between results for individual queries within `pData`.

## Description

This command fulfills the same task as vkCmdWriteMicromapsPropertiesEXT but is executed by the host.

Valid Usage

- VUID-vkWriteMicromapsPropertiesEXT-pMicromaps-07501
  All micromaps in `pMicromaps` must have been constructed prior to the execution of this command

- VUID-vkWriteMicromapsPropertiesEXT-pMicromaps-07502
  All micromaps in `pMicromaps` must have been constructed with `VK_BUILD_MICROMAP_ALLOW_COMPACTION_BIT_EXT` if `queryType` is `VK_QUERY_TYPE_MICROMAP_COMPACTED_SIZE_EXT`

- VUID-vkWriteMicromapsPropertiesEXT-queryType-07503
  `queryType` must be `VK_QUERY_TYPE_MICROMAP_COMPACTED_SIZE_EXT` or `VK_QUERY_TYPE_MICROMAP_SERIALIZATION_SIZE_EXT`

- VUID-vkWriteMicromapsPropertiesEXT-queryType-10071
  If `queryType` is `VK_QUERY_TYPE_MICROMAP_SERIALIZATION_SIZE_EXT` or `VK_QUERY_TYPE_MICROMAP_COMPACTED_SIZE_EXT` then `stride` must be a multiple of the size of VkDeviceSize

- VUID-vkWriteMicromapsPropertiesEXT-queryType-10072
  If `queryType` is `VK_QUERY_TYPE_MICROMAP_SERIALIZATION_SIZE_EXT` or `VK_QUERY_TYPE_MICROMAP_COMPACTED_SIZE_EXT` then `pData` must point to a VkDeviceSize

- VUID-vkWriteMicromapsPropertiesEXT-dataSize-07576
  `dataSize` must be greater than or equal to `micromapCount`*`stride`

- VUID-vkWriteMicromapsPropertiesEXT-buffer-07577
  The `buffer` used to create each micromap in `pMicromaps` must be bound to host-visible device memory

- VUID-vkWriteMicromapsPropertiesEXT-micromapHostCommands-07578
  The `VkPhysicalDeviceOpacityMicromapFeaturesEXT`::`micromapHostCommands` feature must be enabled

- VUID-vkWriteMicromapsPropertiesEXT-buffer-07579
  The `buffer` used to create each micromap in `pMicromaps` must be bound to memory that was not allocated with multiple instances

Valid Usage (Implicit)

- VUID-vkWriteMicromapsPropertiesEXT-device-parameter
  `device` must be a valid VkDevice handle

- VUID-vkWriteMicromapsPropertiesEXT-pMicromaps-parameter
  `pMicromaps` must be a valid pointer to an array of `micromapCount` valid VkMicromapEXT handles

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

- VUID-vkWriteMicromapsPropertiesEXT-pData-parameter
  `pData` must be a valid pointer to an array of `dataSize` bytes

- VUID-vkWriteMicromapsPropertiesEXT-micromapCount-arraylength
  `micromapCount` must be greater than `0`

- VUID-vkWriteMicromapsPropertiesEXT-dataSize-arraylength
  `dataSize` must be greater than `0`

- VUID-vkWriteMicromapsPropertiesEXT-pMicromaps-parent
  Each element of `pMicromaps` must have been created, allocated, or retrieved from `device`

Return Codes

On success, this command returns

  - `VK_SUCCESS`

On failure, this command returns

  - `VK_ERROR_OUT_OF_HOST_MEMORY`

  - `VK_ERROR_OUT_OF_DEVICE_MEMORY`

## See Also

VK_EXT_opacity_micromap, VkDevice, VkMicromapEXT, 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 2014-2025 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0