commit ac44cd2b072916b83f079bbfda66636491279d2e
author Zhenyao Mo <zmo@chromium.org> Mon Sep 23 14:57:09 2013 -0400
committer Jamie Madill <jmadill@chromium.org> Tue Sep 24 15:13:06 2013 -0400
tree c32e0d6a587701bc28d32427015af7630278acd4
parent a15f3e84bfc96b9ef97dd10150f8811adcbbdebf

Add an option in ANGLE shader translator to initialize gl_Position to vec4(0.0, 0.0, 0.0, 1.0).

This is to work around driver bugs where shader compile or program link would fail incorrectly if gl_Position is not set in vertex shader.

At the moment at least Linux NVIDIA driver has this bug.

ANGLEBUG=472
R=alokp@chromium.org, kbr@chromium.org

Review URL: https://codereview.appspot.com/13509043

src/compiler/Compiler.cpp

diff --git a/src/compiler/Compiler.cpp b/src/compiler/Compiler.cpp
index 0a91f9b..4afa73d 100644
--- a/src/compiler/Compiler.cpp
+++ b/src/compiler/Compiler.cpp
@@ -8,6 +8,7 @@
 #include "compiler/DetectCallDepth.h"
 #include "compiler/ForLoopUnroll.h"
 #include "compiler/Initialize.h"
+#include "compiler/InitializeGLPosition.h"
 #include "compiler/InitializeParseContext.h"
 #include "compiler/MapLongVariableNames.h"
 #include "compiler/ParseHelper.h"
@@ -196,6 +197,11 @@
         if (success && (compileOptions & SH_MAP_LONG_VARIABLE_NAMES) && hashFunction == NULL)
             mapLongVariableNames(root);
 
+        if (success && shaderType == SH_VERTEX_SHADER && (compileOptions & SH_INIT_GL_POSITION)) {
+            InitializeGLPosition initGLPosition;
+            root->traverse(&initGLPosition);
+        }
+
         if (success && (compileOptions & SH_VARIABLES)) {
             collectVariables(root);
             if (compileOptions & SH_ENFORCE_PACKING_RESTRICTIONS) {