VkGeometryInstanceFlagBitsKHR(3)

# VkGeometryInstanceFlagBitsKHR(3) Manual Page

## Name

VkGeometryInstanceFlagBitsKHR - Instance flag bits

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## C Specification

Possible values of `flags` in the instance modifying the behavior of that instance are:

    // Provided by VK_KHR_acceleration_structure
    typedef enum VkGeometryInstanceFlagBitsKHR {
        VK_GEOMETRY_INSTANCE_TRIANGLE_FACING_CULL_DISABLE_BIT_KHR = 0x00000001,
        VK_GEOMETRY_INSTANCE_TRIANGLE_FLIP_FACING_BIT_KHR = 0x00000002,
        VK_GEOMETRY_INSTANCE_FORCE_OPAQUE_BIT_KHR = 0x00000004,
        VK_GEOMETRY_INSTANCE_FORCE_NO_OPAQUE_BIT_KHR = 0x00000008,
      // Provided by VK_EXT_opacity_micromap
        VK_GEOMETRY_INSTANCE_FORCE_OPACITY_MICROMAP_2_STATE_BIT_EXT = 0x00000010,
      // Provided by VK_EXT_opacity_micromap
        VK_GEOMETRY_INSTANCE_DISABLE_OPACITY_MICROMAPS_BIT_EXT = 0x00000020,
        VK_GEOMETRY_INSTANCE_TRIANGLE_FRONT_COUNTERCLOCKWISE_BIT_KHR = VK_GEOMETRY_INSTANCE_TRIANGLE_FLIP_FACING_BIT_KHR,
      // Provided by VK_NV_ray_tracing
        VK_GEOMETRY_INSTANCE_TRIANGLE_CULL_DISABLE_BIT_NV = VK_GEOMETRY_INSTANCE_TRIANGLE_FACING_CULL_DISABLE_BIT_KHR,
      // Provided by VK_NV_ray_tracing
        VK_GEOMETRY_INSTANCE_TRIANGLE_FRONT_COUNTERCLOCKWISE_BIT_NV = VK_GEOMETRY_INSTANCE_TRIANGLE_FRONT_COUNTERCLOCKWISE_BIT_KHR,
      // Provided by VK_NV_ray_tracing
        VK_GEOMETRY_INSTANCE_FORCE_OPAQUE_BIT_NV = VK_GEOMETRY_INSTANCE_FORCE_OPAQUE_BIT_KHR,
      // Provided by VK_NV_ray_tracing
        VK_GEOMETRY_INSTANCE_FORCE_NO_OPAQUE_BIT_NV = VK_GEOMETRY_INSTANCE_FORCE_NO_OPAQUE_BIT_KHR,
      // Provided by VK_EXT_opacity_micromap
      // VK_GEOMETRY_INSTANCE_FORCE_OPACITY_MICROMAP_2_STATE_EXT is a legacy alias
        VK_GEOMETRY_INSTANCE_FORCE_OPACITY_MICROMAP_2_STATE_EXT = VK_GEOMETRY_INSTANCE_FORCE_OPACITY_MICROMAP_2_STATE_BIT_EXT,
      // Provided by VK_EXT_opacity_micromap
      // VK_GEOMETRY_INSTANCE_DISABLE_OPACITY_MICROMAPS_EXT is a legacy alias
        VK_GEOMETRY_INSTANCE_DISABLE_OPACITY_MICROMAPS_EXT = VK_GEOMETRY_INSTANCE_DISABLE_OPACITY_MICROMAPS_BIT_EXT,
    } VkGeometryInstanceFlagBitsKHR;

    // Provided by VK_NV_ray_tracing
    // Equivalent to VkGeometryInstanceFlagBitsKHR
    typedef VkGeometryInstanceFlagBitsKHR VkGeometryInstanceFlagBitsNV;

## Description

- VK_GEOMETRY_INSTANCE_TRIANGLE_FACING_CULL_DISABLE_BIT_KHR disables face culling for this instance.

- VK_GEOMETRY_INSTANCE_TRIANGLE_FLIP_FACING_BIT_KHR specifies that the facing determination for geometry in this instance is inverted. Because the facing is determined in object space, an instance transform does not change the winding, but a geometry transform does.

- VK_GEOMETRY_INSTANCE_FORCE_OPAQUE_BIT_KHR causes this instance to act as though VK_GEOMETRY_OPAQUE_BIT_KHR were specified on all geometries referenced by this instance. This behavior can be overridden by the SPIR-V `NoOpaqueKHR` ray flag.

- VK_GEOMETRY_INSTANCE_FORCE_NO_OPAQUE_BIT_KHR causes this instance to act as though VK_GEOMETRY_OPAQUE_BIT_KHR were not specified on all geometries referenced by this instance. This behavior can be overridden by the SPIR-V `OpaqueKHR` ray flag.

VK_GEOMETRY_INSTANCE_FORCE_NO_OPAQUE_BIT_KHR and VK_GEOMETRY_INSTANCE_FORCE_OPAQUE_BIT_KHR must not be used in the same flag.

## See Also

VK_KHR_acceleration_structure, VK_NV_ray_tracing, VkGeometryInstanceFlagsKHR

## 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