1  include::meta/VK_EXT_post_depth_coverage.txt[]
 2  
 3  *Last Modified Date*::
 4      2017-07-17
 5  *Interactions and External Dependencies*::
 6    - This extension requires the
 7      https://www.khronos.org/registry/spir-v/extensions/KHR/SPV_KHR_post_depth_coverage.html[`SPV_KHR_post_depth_coverage`]
 8      SPIR-V extension.
 9    - This extension requires
10      https://www.khronos.org/registry/OpenGL/extensions/ARB/ARB_post_depth_coverage.txt[`GL_ARB_post_depth_coverage`]
11      or
12      https://www.khronos.org/registry/OpenGL/extensions/EXT/EXT_post_depth_coverage.txt[`GL_EXT_post_depth_coverage`]
13      for GLSL-based source languages.
14  *Contributors*::
15    - Jeff Bolz, NVIDIA
16  
17  This extension adds support for the following SPIR-V extension in Vulkan:
18  
19    * `SPV_KHR_post_depth_coverage`
20  
21  which allows the fragment shader to control whether values in the
22  code:SampleMask built-in input variable reflect the coverage after the
23  <<fragops-early,early per-fragment>> depth and stencil tests are applied.
24  
25  This extension adds a new code:PostDepthCoverage execution mode under the
26  code:SampleMaskPostDepthCoverage capability.
27  When this mode is specified along with code:EarlyFragmentTests, the value of
28  an input variable decorated with the
29  <<interfaces-builtin-variables-samplemask, code:SampleMask>> built-in
30  reflects the coverage after the <<shaders-fragment-earlytest, early fragment
31  tests>> are applied.
32  Otherwise, it reflects the coverage before the depth and stencil tests.
33  
34  When using GLSL source-based shading languages, the code:post_depth_coverage
35  layout qualifier from GL_ARB_post_depth_coverage or
36  GL_EXT_post_depth_coverage maps to the code:PostDepthCoverage execution
37  mode.
38  
39  === New Object Types
40  
41  None.
42  
43  === New Enum Constants
44  
45  None.
46  
47  === New Enums
48  
49  None.
50  
51  === New Structures
52  
53  None.
54  
55  === New Functions
56  
57  None.
58  
59  === New Built-In Variables
60  
61  None.
62  
63  === New Variable Decoration
64  
65  None.
66  
67  === New SPIR-V Capabilities
68  
69    * <<spirvenv-capabilities-table-postdepthcoverage,SampleMaskPostDepthCoverage>>
70  
71  === Issues
72  
73  None yet.
74  
75  === Version History
76  
77    * Revision 1, 2017-07-17 (Daniel Koch)
78      - Internal revisions