VkOpacityMicromapSpecialIndexKHR(3)

# VkOpacityMicromapSpecialIndexKHR(3) Manual Page

## Name

VkOpacityMicromapSpecialIndexKHR - Enum for special indices in the opacity micromap

## C Specification

The VkOpacityMicromapSpecialIndexKHR enumeration is defined as:

    // Provided by VK_KHR_opacity_micromap
    typedef enum VkOpacityMicromapSpecialIndexKHR {
        VK_OPACITY_MICROMAP_SPECIAL_INDEX_FULLY_TRANSPARENT_KHR = -1,
        VK_OPACITY_MICROMAP_SPECIAL_INDEX_FULLY_OPAQUE_KHR = -2,
        VK_OPACITY_MICROMAP_SPECIAL_INDEX_FULLY_UNKNOWN_TRANSPARENT_KHR = -3,
        VK_OPACITY_MICROMAP_SPECIAL_INDEX_FULLY_UNKNOWN_OPAQUE_KHR = -4,
      // Provided by VK_EXT_opacity_micromap with VK_NV_cluster_acceleration_structure
        VK_OPACITY_MICROMAP_SPECIAL_INDEX_CLUSTER_GEOMETRY_DISABLE_OPACITY_MICROMAP_NV = -5,
      // Provided by VK_EXT_opacity_micromap
        VK_OPACITY_MICROMAP_SPECIAL_INDEX_FULLY_TRANSPARENT_EXT = VK_OPACITY_MICROMAP_SPECIAL_INDEX_FULLY_TRANSPARENT_KHR,
      // Provided by VK_EXT_opacity_micromap
        VK_OPACITY_MICROMAP_SPECIAL_INDEX_FULLY_OPAQUE_EXT = VK_OPACITY_MICROMAP_SPECIAL_INDEX_FULLY_OPAQUE_KHR,
      // Provided by VK_EXT_opacity_micromap
        VK_OPACITY_MICROMAP_SPECIAL_INDEX_FULLY_UNKNOWN_TRANSPARENT_EXT = VK_OPACITY_MICROMAP_SPECIAL_INDEX_FULLY_UNKNOWN_TRANSPARENT_KHR,
      // Provided by VK_EXT_opacity_micromap
        VK_OPACITY_MICROMAP_SPECIAL_INDEX_FULLY_UNKNOWN_OPAQUE_EXT = VK_OPACITY_MICROMAP_SPECIAL_INDEX_FULLY_UNKNOWN_OPAQUE_KHR,
    } VkOpacityMicromapSpecialIndexKHR;

    // Provided by VK_EXT_opacity_micromap
    // Equivalent to VkOpacityMicromapSpecialIndexKHR
    typedef VkOpacityMicromapSpecialIndexKHR VkOpacityMicromapSpecialIndexEXT;

## Description

- VK_OPACITY_MICROMAP_SPECIAL_INDEX_FULLY_TRANSPARENT_KHR specifies that the entire triangle is fully transparent.

- VK_OPACITY_MICROMAP_SPECIAL_INDEX_FULLY_OPAQUE_KHR specifies that the entire triangle is fully opaque.

- VK_OPACITY_MICROMAP_SPECIAL_INDEX_FULLY_UNKNOWN_TRANSPARENT_KHR specifies that the entire triangle is unknown-transparent.

- VK_OPACITY_MICROMAP_SPECIAL_INDEX_FULLY_UNKNOWN_OPAQUE_KHR specifies that the entire triangle is unknown-opaque.

- VK_OPACITY_MICROMAP_SPECIAL_INDEX_CLUSTER_GEOMETRY_DISABLE_OPACITY_MICROMAP_NV specifies that Opacity Micromap will be disabled for this triangle and opacity value will be picked from VkClusterAccelerationStructureBuildTriangleClusterInfoNV::`baseGeometryIndexAndGeometryFlags` instead. Note that this special index is only valid for Cluster Geometry.

## See Also

VK_EXT_opacity_micromap, VK_KHR_opacity_micromap

## 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