C Specification

To create a micromap, call:

// Provided by VK_EXT_opacity_micromap
VkResult vkCreateMicromapEXT(
    VkDevice                                    device,
    const VkMicromapCreateInfoEXT*              pCreateInfo,
    const VkAllocationCallbacks*                pAllocator,
    VkMicromapEXT*                              pMicromap);


  • device is the logical device that creates the acceleration structure object.

  • pCreateInfo is a pointer to a VkMicromapCreateInfoEXT structure containing parameters affecting creation of the micromap.

  • pAllocator controls host memory allocation as described in the Memory Allocation chapter.

  • pMicromap is a pointer to a VkMicromapEXT handle in which the resulting micromap object is returned.


Similar to other objects in Vulkan, the micromap creation merely creates an object with a specific “shape”. The type and quantity of geometry that can be built into a micromap is determined by the parameters of VkMicromapCreateInfoEXT.

The micromap data is stored in the object referred to by VkMicromapCreateInfoEXT::buffer. Once memory has been bound to that buffer, it must be populated by micromap build or micromap copy commands such as vkCmdBuildMicromapsEXT, vkBuildMicromapsEXT, vkCmdCopyMicromapEXT, and vkCopyMicromapEXT.


The expected usage for a trace capture/replay tool is that it will serialize and later deserialize the micromap data using micromap copy commands. During capture the tool will use vkCopyMicromapToMemoryEXT or vkCmdCopyMicromapToMemoryEXT with a mode of VK_COPY_MICROMAP_MODE_SERIALIZE_EXT, and vkCopyMemoryToMicromapEXT or vkCmdCopyMemoryToMicromapEXT with a mode of VK_COPY_MICROMAP_MODE_DESERIALIZE_EXT during replay.

The input buffers passed to micromap build commands will be referenced by the implementation for the duration of the command. Micromaps must be fully self-contained. The application can reuse or free any memory which was used by the command as an input or as scratch without affecting the results of a subsequent acceleration structure build using the micromap or traversal of that acceleration structure.

Valid Usage
Valid Usage (Implicit)
  • VUID-vkCreateMicromapEXT-device-parameter
    device must be a valid VkDevice handle

  • VUID-vkCreateMicromapEXT-pCreateInfo-parameter
    pCreateInfo must be a valid pointer to a valid VkMicromapCreateInfoEXT structure

  • VUID-vkCreateMicromapEXT-pAllocator-parameter
    If pAllocator is not NULL, pAllocator must be a valid pointer to a valid VkAllocationCallbacks structure

  • VUID-vkCreateMicromapEXT-pMicromap-parameter
    pMicromap must be a valid pointer to a VkMicromapEXT handle

Return Codes
On success, this command returns

On failure, this command returns


See Also

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 2014-2024 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0