C Specification

To create an acceleration structure, call:

// Provided by VK_KHR_acceleration_structure
VkResult vkCreateAccelerationStructureKHR(
    VkDevice                                    device,
    const VkAccelerationStructureCreateInfoKHR* pCreateInfo,
    const VkAllocationCallbacks*                pAllocator,
    VkAccelerationStructureKHR*                 pAccelerationStructure);

Parameters

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

  • pCreateInfo is a pointer to a VkAccelerationStructureCreateInfoKHR structure containing parameters affecting creation of the acceleration structure.

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

  • pAccelerationStructure is a pointer to a VkAccelerationStructureKHR handle in which the resulting acceleration structure object is returned.

Description

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

The acceleration structure data is stored in the object referred to by VkAccelerationStructureCreateInfoKHR::buffer. Once memory has been bound to that buffer, it must be populated by acceleration structure build or acceleration structure copy commands such as vkCmdBuildAccelerationStructuresKHR, vkBuildAccelerationStructuresKHR, vkCmdCopyAccelerationStructureKHR, and vkCopyAccelerationStructureKHR.

Note

The expected usage for a trace capture/replay tool is that it will serialize and later deserialize the acceleration structure data using acceleration structure copy commands. During capture the tool will use vkCopyAccelerationStructureToMemoryKHR or vkCmdCopyAccelerationStructureToMemoryKHR with a mode of VK_COPY_ACCELERATION_STRUCTURE_MODE_SERIALIZE_KHR, and vkCopyMemoryToAccelerationStructureKHR or vkCmdCopyMemoryToAccelerationStructureKHR with a mode of VK_COPY_ACCELERATION_STRUCTURE_MODE_DESERIALIZE_KHR during replay.
Note

Memory does not need to be bound to the underlying buffer when vkCreateAccelerationStructureKHR is called.

The input buffers passed to acceleration structure build commands will be referenced by the implementation for the duration of the command. After the command completes, the acceleration structure may hold a reference to any acceleration structure specified by an active instance contained therein. Apart from this referencing, acceleration structures 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 ray traversal.

Valid Usage
Valid Usage (Implicit)

  • VUID-vkCreateAccelerationStructureKHR-device-parameter
    device must be a valid VkDevice handle

  • VUID-vkCreateAccelerationStructureKHR-pCreateInfo-parameter
    pCreateInfo must be a valid pointer to a valid VkAccelerationStructureCreateInfoKHR structure

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

  • VUID-vkCreateAccelerationStructureKHR-pAccelerationStructure-parameter
    pAccelerationStructure must be a valid pointer to a VkAccelerationStructureKHR handle

Return Codes
On success, this command returns

  • VK_SUCCESS

On failure, this command returns

  • VK_ERROR_OUT_OF_HOST_MEMORY

  • VK_ERROR_INVALID_OPAQUE_CAPTURE_ADDRESS_KHR

See Also

VK_KHR_acceleration_structure, VkAccelerationStructureCreateInfoKHR, VkAccelerationStructureKHR, VkAllocationCallbacks, VkDevice

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