# vkCmdCopyMicromapToMemoryEXT(3) Manual Page

## Name

vkCmdCopyMicromapToMemoryEXT - Copy a micromap to device memory

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## C Specification

To copy a micromap to device memory call:

    // Provided by VK_EXT_opacity_micromap
    void vkCmdCopyMicromapToMemoryEXT(
        VkCommandBuffer                             commandBuffer,
        const VkCopyMicromapToMemoryInfoEXT*        pInfo);

## Parameters

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

- `pInfo` is an a pointer to a VkCopyMicromapToMemoryInfoEXT structure defining the copy operation.

## Description

Accesses to `pInfo->src` must be synchronized with the VK_PIPELINE_STAGE_2_MICROMAP_BUILD_BIT_EXT pipeline stage and an access type of VK_ACCESS_2_MICROMAP_READ_BIT_EXT. Accesses to the buffer indicated by `pInfo->dst.deviceAddress` must be synchronized with the VK_PIPELINE_STAGE_2_MICROMAP_BUILD_BIT_EXT pipeline stage and an access type of VK_ACCESS_TRANSFER_WRITE_BIT.

This command produces the same results as vkCopyMicromapToMemoryEXT, 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 vkCmdCopyMemoryToMicromapEXT or vkCopyMemoryToMicromapEXT.

The defined header structure for the serialized data consists of:

- VK_UUID_SIZE bytes of data matching `VkPhysicalDeviceIDProperties`::`driverUUID`

- VK_UUID_SIZE bytes of data identifying the compatibility for comparison using vkGetDeviceMicromapCompatibilityEXT The serialized data is written to the buffer (or read from the buffer) according to the host endianness.

Valid Usage

- VUID-vkCmdCopyMicromapToMemoryEXT-pInfo-07536
  `pInfo->dst.deviceAddress` must be a valid VkDeviceAddress

- VUID-vkCmdCopyMicromapToMemoryEXT-pInfo-07537
  `pInfo->dst.deviceAddress` must be aligned to `256` bytes

- VUID-vkCmdCopyMicromapToMemoryEXT-pInfo-07538
  If the buffer pointed to by `pInfo->dst.deviceAddress` is non-sparse then it must be bound completely and contiguously to a single VkDeviceMemory object

- VUID-vkCmdCopyMicromapToMemoryEXT-buffer-07539
  The `buffer` used to create `pInfo->src` must be bound to device memory

Valid Usage (Implicit)

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

- VUID-vkCmdCopyMicromapToMemoryEXT-pInfo-parameter
  `pInfo` must be a valid pointer to a valid VkCopyMicromapToMemoryInfoEXT structure

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

- VUID-vkCmdCopyMicromapToMemoryEXT-commandBuffer-cmdpool
  The `VkCommandPool` that `commandBuffer` was allocated from must support VK_QUEUE_COMPUTE_BIT operations

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

- VUID-vkCmdCopyMicromapToMemoryEXT-suspended
  This command must not be called between suspended render pass instances

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

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 | VK_QUEUE_COMPUTE_BIT | Action

Conditional Rendering

vkCmdCopyMicromapToMemoryEXT is not affected by conditional rendering

## See Also

VK_EXT_opacity_micromap, VkCommandBuffer, VkCopyMicromapToMemoryInfoEXT

## 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 2014-2026 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0