1// Copyright 2017-2021 The Khronos Group Inc. 2// 3// SPDX-License-Identifier: CC-BY-4.0 4 5include::{generated}/meta/{refprefix}VK_EXT_post_depth_coverage.txt[] 6 7=== Other Extension Metadata 8 9*Last Modified Date*:: 10 2017-07-17 11*Interactions and External Dependencies*:: 12 - This extension requires 13 {spirv}/KHR/SPV_KHR_post_depth_coverage.html[`SPV_KHR_post_depth_coverage`] 14 - This extension provides API support for 15 https://www.khronos.org/registry/OpenGL/extensions/ARB/ARB_post_depth_coverage.txt[`GL_ARB_post_depth_coverage`] 16 and 17 https://www.khronos.org/registry/OpenGL/extensions/EXT/EXT_post_depth_coverage.txt[`GL_EXT_post_depth_coverage`] 18*Contributors*:: 19 - Jeff Bolz, NVIDIA 20 21=== Description 22 23This extension adds support for the following SPIR-V extension in Vulkan: 24 25 * `SPV_KHR_post_depth_coverage` 26 27which allows the fragment shader to control whether values in the 28code:SampleMask built-in input variable reflect the coverage after early 29<<fragops-depth,depth>> and <<fragops-stencil,stencil>> tests are applied. 30 31This extension adds a new code:PostDepthCoverage execution mode under the 32code:SampleMaskPostDepthCoverage capability. 33When this mode is specified along with code:EarlyFragmentTests, the value of 34an input variable decorated with the 35<<interfaces-builtin-variables-samplemask, code:SampleMask>> built-in 36reflects the coverage after the <<shaders-fragment-earlytest, early fragment 37tests>> are applied. 38Otherwise, it reflects the coverage before the depth and stencil tests. 39 40When using GLSL source-based shading languages, the code:post_depth_coverage 41layout qualifier from GL_ARB_post_depth_coverage or 42GL_EXT_post_depth_coverage maps to the code:PostDepthCoverage execution 43mode. 44 45include::{generated}/interfaces/VK_EXT_post_depth_coverage.txt[] 46 47=== New SPIR-V Capabilities 48 49 * <<spirvenv-capabilities-table-SampleMaskPostDepthCoverage,SampleMaskPostDepthCoverage>> 50 51=== Version History 52 53 * Revision 1, 2017-07-17 (Daniel Koch) 54 - Internal revisions 55