Add GLSL support for texelFetch

src/gpu/glsl/GrGLSLShaderBuilder.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 "GrSwizzle.h"
 #include "glsl/GrGLSLShaderBuilder.h"
 #include "glsl/GrGLSLCaps.h"
@@ skipping 75 matching lines @@
                          coordName,
                          coordName);
         }
     } else {
         out->appendf("%s(%s, %s)",
                      GrGLSLTexture2DFunctionName(varyingType, samplerType, glslCaps->generation()),
                      uniformHandler->getUniformCStr(sampler.fSamplerUniform),
                      coordName);
     }
 
-    // This refers to any swizzling we may need to get from some backend internal format to the
-    // format used in GrPixelConfig. If this is implemented by the GrGpu object, then swizzle will
-    // be rgba. For shader prettiness we omit the swizzle rather than appending ".rgba".
-    const GrSwizzle& configSwizzle = glslCaps->configTextureSwizzle(sampler.config());
-
-    if (configSwizzle != GrSwizzle::RGBA()) {
-        out->appendf(".%s", configSwizzle.c_str());
-    }
+    this->appendTextureSwizzle(out, sampler.config());
 }
 
 void GrGLSLShaderBuilder::appendTextureLookup(const GrGLSLSampler& sampler,
                                               const char* coordName,
                                               GrSLType varyingType) {
     this->appendTextureLookup(&this->code(), sampler, coordName, varyingType);
 }
 
 void GrGLSLShaderBuilder::appendTextureLookupAndModulate(const char* modulation,
                                                          const GrGLSLSampler& sampler,
                                                          const char* coordName,
                                                          GrSLType varyingType) {
     SkString lookup;
     this->appendTextureLookup(&lookup, sampler, coordName, varyingType);
     this->codeAppend((GrGLSLExpr4(modulation) * GrGLSLExpr4(lookup)).c_str());
 }
 
+void GrGLSLShaderBuilder::appendTexelFetch(SkString* out,
+                                           const GrGLSLSampler& sampler,
+                                           const char* coordExpr) const {
+    const GrGLSLUniformHandler* uniformHandler = fProgramBuilder->uniformHandler();
+    SkASSERT(fProgramBuilder->glslCaps()->texelFetchSupport());
+    SkASSERT(GrSLTypeIsSamplerType(
+             uniformHandler->getUniformVariable(sampler.fSamplerUniform).getType()));
+
+    out->appendf("texelFetch(%s, %s)",
+                 uniformHandler->getUniformCStr(sampler.fSamplerUniform),
+                 coordExpr);
+
+    this->appendTextureSwizzle(out, sampler.config());
+}
+
+void GrGLSLShaderBuilder::appendTexelFetch(const GrGLSLSampler& sampler, const char* coordExpr) {
+    this->appendTexelFetch(&this->code(), sampler, coordExpr);
+}
+
+void GrGLSLShaderBuilder::appendTextureSwizzle(SkString* out, GrPixelConfig config) const {
+    const GrSwizzle& configSwizzle = fProgramBuilder->glslCaps()->configTextureSwizzle(config);
+
+    if (configSwizzle != GrSwizzle::RGBA()) {
+        out->appendf(".%s", configSwizzle.c_str());
+    }
+}
+
 bool GrGLSLShaderBuilder::addFeature(uint32_t featureBit, const char* extensionName) {
     if (featureBit & fFeaturesAddedMask) {
         return false;
     }
     this->extensions().appendf("#extension %s: require\n", extensionName);
     fFeaturesAddedMask |= featureBit;
     return true;
 }
 
 void GrGLSLShaderBuilder::appendDecls(const VarArray& vars, SkString* out) const {
@@ skipping 42 matching lines @@
     // append the 'footer' to code
     this->code().append("}");
 
     for (int i = 0; i <= fCodeIndex; i++) {
         fCompilerStrings[i] = fShaderStrings[i].c_str();
         fCompilerStringLengths[i] = (int)fShaderStrings[i].size();
     }
 
     fFinalized = true;
 }