commit a9beed30dd4b2e26452479bc722a35039ce0fb42
author Alexis Hetu <sugoi@google.com> Tue Dec 13 16:48:01 2016 -0500
committer Alexis Hétu <sugoi@google.com> Wed Dec 14 17:51:45 2016 +0000
tree 5440039aee109369e9b36f43df7e49b16661dadf
parent 2e363b0b42fdb3070c6c5f6c27f8622467b63717

Fixed using GL_SAMPLE_ALPHA_TO_COVERAGE

A few things were failing when trying to use
GL_SAMPLE_ALPHA_TO_COVERAGE:
- The alpha test should not be skipped when
  GL_SAMPLE_ALPHA_TO_COVERAGE is set, otherwise
  no computation is performed.
- The alpha reference value was wrong
  (the alpha-to-coverage ramp is centered around it)

Change-Id: Ib9849868d267ca49fb3f0112192af8f207d34307
Reviewed-on: https://swiftshader-review.googlesource.com/8308
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Alexis Hétu <sugoi@google.com>

src/OpenGL/libGLESv2/Device.cpp

diff --git a/src/OpenGL/libGLESv2/Device.cpp b/src/OpenGL/libGLESv2/Device.cpp
index 2e7a2e3..da1583f 100644
--- a/src/OpenGL/libGLESv2/Device.cpp
+++ b/src/OpenGL/libGLESv2/Device.cpp
@@ -52,7 +52,7 @@
 		setDestBlendFactor(BLEND_ZERO);
 		setCullMode(CULL_COUNTERCLOCKWISE);
 		setDepthCompare(DEPTH_LESSEQUAL);
-		setAlphaReference(0.0f);
+		setAlphaReference(127.5f);
 		setAlphaCompare(ALPHA_ALWAYS);
 		setAlphaBlendEnable(false);
 		setFogEnable(false);

src/Renderer/Context.cpp

diff --git a/src/Renderer/Context.cpp b/src/Renderer/Context.cpp
index 1a35873..7e44441 100644
--- a/src/Renderer/Context.cpp
+++ b/src/Renderer/Context.cpp
@@ -515,6 +515,7 @@
 
 	bool Context::alphaTestActive()
 	{
+		if(transparencyAntialiasing != TRANSPARENCY_NONE) return true;
 		if(!alphaTestEnable) return false;
 		if(alphaCompareMode == ALPHA_ALWAYS) return false;
 		if(alphaReference == 0.0f && alphaCompareMode == ALPHA_GREATEREQUAL) return false;

src/Renderer/PixelProcessor.hpp

diff --git a/src/Renderer/PixelProcessor.hpp b/src/Renderer/PixelProcessor.hpp
index e5ab442..94d52d3 100644
--- a/src/Renderer/PixelProcessor.hpp
+++ b/src/Renderer/PixelProcessor.hpp
@@ -122,7 +122,7 @@
 
 			bool alphaTestActive() const
 			{
-				return alphaCompareMode != ALPHA_ALWAYS;
+				return (alphaCompareMode != ALPHA_ALWAYS) || (transparencyAntialiasing != TRANSPARENCY_NONE);
 			}
 
 			bool pixelFogActive() const