Bug fix for es 3.00 fb fetch

src/gpu/gl/builders/GrGLFragmentShaderBuilder.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrGLFragmentShaderBuilder.h"
 #include "GrGLShaderStringBuilder.h"
 #include "GrGLProgramBuilder.h"
@@ skipping 57 matching lines @@
     }
 }
 
 GrGLFragmentShaderBuilder::GrGLFragmentShaderBuilder(GrGLProgramBuilder* program,
                                                      const GrGLProgramDesc& desc)
     : INHERITED(program)
     , fHasCustomColorOutput(false)
     , fHasSecondaryOutput(false)
     , fSetupFragPosition(false)
     , fTopLeftFragPosRead(kTopLeftFragPosRead_FragPosKey == desc.getHeader().fFragPosKey)
+    , fCustomColorOutputIndex(-1)
     , fHasReadDstColor(false)
     , fHasReadFragmentPosition(false) {
 }
 
 bool GrGLFragmentShaderBuilder::enableFeature(GLSLFeature feature) {
     switch (feature) {
         case kStandardDerivatives_GLSLFeature: {
             GrGpuGL* gpu = fProgramBuilder->gpu();
             if (!gpu->glCaps().shaderDerivativeSupport()) {
                 return false;
@@ skipping 77 matching lines @@
     }
 }
 
 const char* GrGLFragmentShaderBuilder::dstColor() {
     fHasReadDstColor = true;
 
     GrGpuGL* gpu = fProgramBuilder->gpu();
     if (gpu->glCaps().fbFetchSupport()) {
         this->addFeature(1 << (GrGLFragmentShaderBuilder::kLastGLSLPrivateFeature + 1),
                          gpu->glCaps().fbFetchExtensionString());
-        return gpu->glCaps().fbFetchColorName();
+
+        // On ES 3.0 we have to declare this, and use the custom color output name
+        const char* fbFetchColorName = gpu->glCaps().fbFetchColorName();
+        if (gpu->glslGeneration() >= k330_GrGLSLGeneration) {
+            this->enableCustomOutput();
+            fOutputs[fCustomColorOutputIndex].setTypeModifier(GrShaderVar::kInOut_TypeModifier);
+            fbFetchColorName = declared_color_output_name();
+        }
+        return fbFetchColorName;
     } else if (fProgramBuilder->fUniformHandles.fDstCopySamplerUni.isValid()) {
         return kDstCopyColorName;
     } else {
         return "";
     }
 }
 
 void GrGLFragmentShaderBuilder::emitCodeToReadDstTexture() {
     bool topDown = SkToBool(kTopLeftOrigin_DstReadKeyBit & fProgramBuilder->header().fDstReadKey);
     const char* dstCopyTopLeftName;
@@ skipping 30 matching lines @@
     }
     this->codeAppendf("vec4 %s = ", GrGLFragmentShaderBuilder::kDstCopyColorName);
     this->appendTextureLookup(dstCopySamplerName,
                               "_dstTexCoord",
                               configMask,
                               "rgba");
     this->codeAppend(";");
 }
 
 void GrGLFragmentShaderBuilder::enableCustomOutput() {
-    SkASSERT(!fHasCustomColorOutput);
-    fHasCustomColorOutput = true;
-    fOutputs.push_back().set(kVec4f_GrSLType,
-                             GrGLShaderVar::kOut_TypeModifier,
-                             declared_color_output_name());
+    if (!fHasCustomColorOutput) {
+        fHasCustomColorOutput = true;
+        fCustomColorOutputIndex = fOutputs.count();
+        fOutputs.push_back().set(kVec4f_GrSLType,
+                                 GrGLShaderVar::kOut_TypeModifier,
+                                 declared_color_output_name());
+    }
 }
 
 void GrGLFragmentShaderBuilder::enableSecondaryOutput() {
     SkASSERT(!fHasSecondaryOutput);
     fHasSecondaryOutput = true;
     fOutputs.push_back().set(kVec4f_GrSLType, GrGLShaderVar::kOut_TypeModifier,
                              dual_source_output_name());
 }
 
 const char* GrGLFragmentShaderBuilder::getPrimaryColorOutputName() const {
@@ skipping 96 matching lines @@
 
 void GrGLFragmentShaderBuilder::addVarying(GrSLType type,
                const char* name,
                const char** fsInName,
                GrGLShaderVar::Precision fsPrecision) {
     fInputs.push_back().set(type, GrGLShaderVar::kVaryingIn_TypeModifier, name, fsPrecision);
     if (fsInName) {
         *fsInName = name;
     }
 }