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      1 //
      2 // Copyright (c) 2002-2010 The ANGLE Project Authors. All rights reserved.
      3 // Use of this source code is governed by a BSD-style license that can be
      4 // found in the LICENSE file.
      5 //
      6 
      7 #include "compiler/VersionGLSL.h"
      8 
      9 static const int GLSL_VERSION_110 = 110;
     10 static const int GLSL_VERSION_120 = 120;
     11 
     12 // We need to scan for two things:
     13 // 1. "invariant" keyword: This can occur in both - vertex and fragment shaders
     14 //    but only at the global scope.
     15 // 2. "gl_PointCoord" built-in variable: This can only occur in fragment shader
     16 //    but inside any scope.
     17 // So we need to scan the entire fragment shader but only the global scope
     18 // of vertex shader.
     19 //
     20 // TODO(alokp): The following two cases of invariant decalaration get lost
     21 // during parsing - they do not get carried over to the intermediate tree.
     22 // Handle these cases:
     23 // 1. When a pragma is used to force all output variables to be invariant:
     24 //    - #pragma STDGL invariant(all)
     25 // 2. When a previously decalared or built-in variable is marked invariant:
     26 //    - invariant gl_Position;
     27 //    - varying vec3 color; invariant color;
     28 //
     29 TVersionGLSL::TVersionGLSL(ShShaderType type)
     30     : mShaderType(type),
     31       mVersion(GLSL_VERSION_110)
     32 {
     33 }
     34 
     35 void TVersionGLSL::visitSymbol(TIntermSymbol* node)
     36 {
     37     ASSERT(mShaderType == SH_FRAGMENT_SHADER);
     38 
     39     if (node->getSymbol() == "gl_PointCoord")
     40         updateVersion(GLSL_VERSION_120);
     41 }
     42 
     43 void TVersionGLSL::visitConstantUnion(TIntermConstantUnion*)
     44 {
     45     ASSERT(mShaderType == SH_FRAGMENT_SHADER);
     46 }
     47 
     48 bool TVersionGLSL::visitBinary(Visit, TIntermBinary*)
     49 {
     50     ASSERT(mShaderType == SH_FRAGMENT_SHADER);
     51     return true;
     52 }
     53 
     54 bool TVersionGLSL::visitUnary(Visit, TIntermUnary*)
     55 {
     56     ASSERT(mShaderType == SH_FRAGMENT_SHADER);
     57     return true;
     58 }
     59 
     60 bool TVersionGLSL::visitSelection(Visit, TIntermSelection*)
     61 {
     62     ASSERT(mShaderType == SH_FRAGMENT_SHADER);
     63     return true;
     64 }
     65 
     66 bool TVersionGLSL::visitAggregate(Visit, TIntermAggregate* node)
     67 {
     68     // We need to scan the entire fragment shader but only the global scope
     69     // of vertex shader.
     70     bool visitChildren = mShaderType == SH_FRAGMENT_SHADER ? true : false;
     71 
     72     switch (node->getOp()) {
     73       case EOpSequence:
     74         // We need to visit sequence children to get to global or inner scope.
     75         visitChildren = true;
     76         break;
     77       case EOpDeclaration: {
     78         const TIntermSequence& sequence = node->getSequence();
     79         TQualifier qualifier = sequence.front()->getAsTyped()->getQualifier();
     80         if ((qualifier == EvqInvariantVaryingIn) ||
     81             (qualifier == EvqInvariantVaryingOut)) {
     82             updateVersion(GLSL_VERSION_120);
     83         }
     84         break;
     85       }
     86       default: break;
     87     }
     88 
     89     return visitChildren;
     90 }
     91 
     92 bool TVersionGLSL::visitLoop(Visit, TIntermLoop*)
     93 {
     94     ASSERT(mShaderType == SH_FRAGMENT_SHADER);
     95     return true;
     96 }
     97 
     98 bool TVersionGLSL::visitBranch(Visit, TIntermBranch*)
     99 {
    100     ASSERT(mShaderType == SH_FRAGMENT_SHADER);
    101     return true;
    102 }
    103 
    104 void TVersionGLSL::updateVersion(int version)
    105 {
    106     mVersion = std::max(version, mVersion);
    107 }
    108 
    109