commit 3aa46cbdcb0cc386a53cabe67954a114593c37e5
author Nicolas Capens <capn@google.com> Wed Jun 03 16:33:02 2015 -0400
committer Nicolas Capens <capn@google.com> Wed Jun 03 20:55:39 2015 +0000
tree c7e213ca8818273626828b776780e281652bb347
parent 101e4f0aff739dbe937e0be7f317ab944c8e42db

Use the last triangle vertex for flat shading on OpenGL.

Bug 21559270

Change-Id: I4c2b5eb7076cc459422fbbb397a684c19bd643c2
Reviewed-on: https://swiftshader-review.googlesource.com/3372
Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>

src/Shader/SetupRoutine.cpp

diff --git a/src/Shader/SetupRoutine.cpp b/src/Shader/SetupRoutine.cpp
index fcb1284..675d8a0 100644
--- a/src/Shader/SetupRoutine.cpp
+++ b/src/Shader/SetupRoutine.cpp
@@ -21,6 +21,7 @@
 {
 	extern bool complementaryDepthBuffer;
 	extern TranscendentalPrecision logPrecision;
+	extern bool leadingVertexFirst;
 
 	SetupRoutine::SetupRoutine(const SetupProcessor::State &state) : state(state)
 	{
@@ -546,7 +547,8 @@
 		}
 		else
 		{
-			Float C = *Pointer<Float>(triangle + OFFSET(Triangle,v0) + attribute);
+			int leadingVertex = leadingVertexFirst ? OFFSET(Triangle,v0) : OFFSET(Triangle,v2);
+			Float C = *Pointer<Float>(triangle + leadingVertex + attribute);
 
 			*Pointer<Float4>(primitive + planeEquation + 0, 16) = Float4(0, 0, 0, 0);
 			*Pointer<Float4>(primitive + planeEquation + 16, 16) = Float4(0, 0, 0, 0);