Vulkan-Docs/appendices/VK_EXT_post_depth_coverage.txt

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include::meta/VK_EXT_post_depth_coverage.txt[]
*Last Modified Date*::
2017-07-17
*Interactions and External Dependencies*::
- This extension requires the
https://www.khronos.org/registry/spir-v/extensions/KHR/SPV_KHR_post_depth_coverage.html[`SPV_KHR_post_depth_coverage`]
SPIR-V extension.
- This extension requires
https://www.khronos.org/registry/OpenGL/extensions/ARB/ARB_post_depth_coverage.txt[`GL_ARB_post_depth_coverage`]
or
https://www.khronos.org/registry/OpenGL/extensions/EXT/EXT_post_depth_coverage.txt[`GL_EXT_post_depth_coverage`]
for GLSL-based source languages.
*Contributors*::
- Jeff Bolz, NVIDIA
This extension adds support for the following SPIR-V extension in Vulkan:
* `SPV_KHR_post_depth_coverage`
which allows the fragment shader to control whether values in the
code:SampleMask built-in input variable reflect the coverage after the
<<fragops-early,early per-fragment>> depth and stencil tests are applied.
This extension adds a new code:PostDepthCoverage execution mode under the
code:SampleMaskPostDepthCoverage capability.
When this mode is specified along with code:EarlyFragmentTests, the value of
an input variable decorated with the
<<interfaces-builtin-variables-samplemask, code:SampleMask>> built-in
reflects the coverage after the <<shaders-fragment-earlytest, early fragment
tests>> are applied.
Otherwise, it reflects the coverage before the depth and stencil tests.
When using GLSL source-based shading languages, the code:post_depth_coverage
layout qualifier from GL_ARB_post_depth_coverage or
GL_EXT_post_depth_coverage maps to the code:PostDepthCoverage execution
mode.
=== New Object Types
None.
=== New Enum Constants
None.
=== New Enums
None.
=== New Structures
None.
=== New Functions
None.
=== New Built-In Variables
None.
=== New Variable Decoration
None.
=== New SPIR-V Capabilities
* <<spirvenv-capabilities-table-postdepthcoverage,SampleMaskPostDepthCoverage>>
=== Issues
None yet.
=== Version History
* Revision 1, 2017-07-17 (Daniel Koch)
- Internal revisions