vkCreateMicromapEXT

To create a micromap, call:

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 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.