GLSL backend now emits "#version 120" to legally access invariant keyword and gl_PointCoord built-in variable.
BUG=35
Review URL: http://codereview.appspot.com/2341043
git-svn-id: https://angleproject.googlecode.com/svn/trunk@448 736b8ea6-26fd-11df-bfd4-992fa37f6226
diff --git a/src/compiler/VersionGLSL.cpp b/src/compiler/VersionGLSL.cpp
new file mode 100644
index 0000000..3f87820
--- /dev/null
+++ b/src/compiler/VersionGLSL.cpp
@@ -0,0 +1,108 @@
+//
+// Copyright (c) 2002-2010 The ANGLE Project Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+
+#include "compiler/VersionGLSL.h"
+
+static const int GLSL_VERSION_110 = 110;
+static const int GLSL_VERSION_120 = 120;
+
+// We need to scan for two things:
+// 1. "invariant" keyword: This can occur in both - vertex and fragment shaders
+// but only at the global scope.
+// 2. "gl_PointCoord" built-in variable: This can only occur in fragment shader
+// but inside any scope.
+// So we need to scan the entire fragment shader but only the global scope
+// of vertex shader.
+//
+// TODO(alokp): The following two cases of invariant decalaration get lost
+// during parsing - they do not get carried over to the intermediate tree.
+// Handle these cases:
+// 1. When a pragma is used to force all output variables to be invariant:
+// - #pragma STDGL invariant(all)
+// 2. When a previously decalared or built-in variable is marked invariant:
+// - invariant gl_Position;
+// - varying vec3 color; invariant color;
+//
+TVersionGLSL::TVersionGLSL(ShShaderType type)
+ : mShaderType(type),
+ mVersion(GLSL_VERSION_110)
+{
+}
+
+void TVersionGLSL::visitSymbol(TIntermSymbol* node)
+{
+ ASSERT(mShaderType == SH_FRAGMENT_SHADER);
+
+ if (node->getSymbol() == "gl_PointCoord")
+ updateVersion(GLSL_VERSION_120);
+}
+
+void TVersionGLSL::visitConstantUnion(TIntermConstantUnion*)
+{
+ ASSERT(mShaderType == SH_FRAGMENT_SHADER);
+}
+
+bool TVersionGLSL::visitBinary(Visit, TIntermBinary*)
+{
+ ASSERT(mShaderType == SH_FRAGMENT_SHADER);
+ return true;
+}
+
+bool TVersionGLSL::visitUnary(Visit, TIntermUnary*)
+{
+ ASSERT(mShaderType == SH_FRAGMENT_SHADER);
+ return true;
+}
+
+bool TVersionGLSL::visitSelection(Visit, TIntermSelection*)
+{
+ ASSERT(mShaderType == SH_FRAGMENT_SHADER);
+ return true;
+}
+
+bool TVersionGLSL::visitAggregate(Visit, TIntermAggregate* node)
+{
+ // We need to scan the entire fragment shader but only the global scope
+ // of vertex shader.
+ bool visitChildren = mShaderType == SH_FRAGMENT_SHADER ? true : false;
+
+ switch (node->getOp()) {
+ case EOpSequence:
+ // We need to visit sequence children to get to global or inner scope.
+ visitChildren = true;
+ break;
+ case EOpDeclaration: {
+ const TIntermSequence& sequence = node->getSequence();
+ TQualifier qualifier = sequence.front()->getAsTyped()->getQualifier();
+ if ((qualifier == EvqInvariantVaryingIn) ||
+ (qualifier == EvqInvariantVaryingOut)) {
+ updateVersion(GLSL_VERSION_120);
+ }
+ break;
+ }
+ default: break;
+ }
+
+ return visitChildren;
+}
+
+bool TVersionGLSL::visitLoop(Visit, TIntermLoop*)
+{
+ ASSERT(mShaderType == SH_FRAGMENT_SHADER);
+ return true;
+}
+
+bool TVersionGLSL::visitBranch(Visit, TIntermBranch*)
+{
+ ASSERT(mShaderType == SH_FRAGMENT_SHADER);
+ return true;
+}
+
+void TVersionGLSL::updateVersion(int version)
+{
+ mVersion = std::max(version, mVersion);
+}
+