commit 0690e1aa31d4e0c9f1ab641e5c0dab75a79c026e
author Olli Etuaho <oetuaho@nvidia.com> Thu Dec 21 20:51:38 2017 +0200
committer Commit Bot <commit-bot@chromium.org> Tue Jan 09 10:48:45 2018 +0000
tree 6cbc08ad3fb8b399498ad0cb0b8513552332113b
parent b38dfde0a7237c32b9d6341e834276f486dc7948

Add a workaround to clamp gl_FragDepth

NVIDIA OpenGL drivers at least up to version 388.59 don't clamp
gl_FragDepth when it is written to a floating point depth buffer.
This bug is now worked around by clamping gl_FragDepth in the shader
if it is statically used.

BUG=angleproject:2299
TEST=angle_end2end_tests on NVIDIA

Change-Id: I61589b2b0dd2813c4901a157c8d37e470063773c
Reviewed-on: https://chromium-review.googlesource.com/840842
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>

src/compiler/translator/Compiler.cpp

diff --git a/src/compiler/translator/Compiler.cpp b/src/compiler/translator/Compiler.cpp
index 2d58a28..669365b 100644
--- a/src/compiler/translator/Compiler.cpp
+++ b/src/compiler/translator/Compiler.cpp
@@ -12,6 +12,7 @@
 #include "common/utilities.h"
 #include "compiler/translator/AddAndTrueToLoopCondition.h"
 #include "compiler/translator/CallDAG.h"
+#include "compiler/translator/ClampFragDepth.h"
 #include "compiler/translator/ClampPointSize.h"
 #include "compiler/translator/CollectVariables.h"
 #include "compiler/translator/DeclareAndInitBuiltinsForInstancedMultiview.h"
@@ -641,6 +642,11 @@
         ClampPointSize(root, compileResources.MaxPointSize, &getSymbolTable());
     }
 
+    if (getShaderType() == GL_FRAGMENT_SHADER && (compileOptions & SH_CLAMP_FRAG_DEPTH))
+    {
+        ClampFragDepth(root, &getSymbolTable());
+    }
+
     if (compileOptions & SH_REWRITE_VECTOR_SCALAR_ARITHMETIC)
     {
         VectorizeVectorScalarArithmetic(root, &getSymbolTable());