VK_HUAWEI_invocation_mask

Other Extension Metadata

Last Modified Date

2021-05-27

Interactions and External Dependencies

This extension requires VK_KHR_ray_tracing_pipeline, which allow to bind an invocation mask image before the ray tracing command
This extension requires VK_KHR_synchronization2, which allows new pipeline stage for the invocation mask image

Contributors

Yunpeng Zhu
Juntao Li, Huawei
Liang Chen, Huawei
Shaozhuang Shi, Huawei
Hailong Chu, Huawei

The rays to trace may be sparse in some use cases. For example, the scene only have a few regions to reflect. Providing an invocation mask image to the ray tracing commands could potentially give the hardware the hint to do certain optimization without invoking an additional pass to compact the ray buffer.

New Commands

vkCmdBindInvocationMaskHUAWEI

New Structures

Extending VkPhysicalDeviceFeatures2, VkDeviceCreateInfo:
- VkPhysicalDeviceInvocationMaskFeaturesHUAWEI

New Enum Constants

VK_HUAWEI_INVOCATION_MASK_EXTENSION_NAME
VK_HUAWEI_INVOCATION_MASK_SPEC_VERSION
Extending VkAccessFlagBits2:
- VK_ACCESS_2_INVOCATION_MASK_READ_BIT_HUAWEI
Extending VkImageUsageFlagBits:
- VK_IMAGE_USAGE_INVOCATION_MASK_BIT_HUAWEI
Extending VkPipelineStageFlagBits2:
- VK_PIPELINE_STAGE_2_INVOCATION_MASK_BIT_HUAWEI
Extending VkStructureType:
- VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_INVOCATION_MASK_FEATURES_HUAWEI

Examples

RT mask is updated before each traceRay.

Step 1. Generate InvocationMask.

//the rt mask image bind as color attachment in the fragment shader
Layout(location = 2) out vec4 outRTmask
vec4 mask = vec4(x,x,x,x);
outRTmask = mask;

Step 2. traceRay with InvocationMask

vkCmdBindPipeline(
    commandBuffers[imageIndex],
    VK_PIPELINE_BIND_POINT_RAY_TRACING_KHR, m_rtPipeline);
    vkCmdBindDescriptorSets(commandBuffers[imageIndex],
    VK_PIPELINE_BIND_POINT_RAY_TRACING_NV,
    m_rtPipelineLayout, 0, 1, &m_rtDescriptorSet,
    0, nullptr);

vkCmdBindInvocationMaskHUAWEI(
    commandBuffers[imageIndex],
    InvocationMaskimageView,
    InvocationMaskimageLayout);
    vkCmdTraceRaysKHR(commandBuffers[imageIndex],
    pRaygenShaderBindingTable,
    pMissShaderBindingTable,
    swapChainExtent.width,
    swapChainExtent.height, 1);

Version History

Revision 1, 2021-05-27 (Yunpeng Zhu)
- Initial draft.