4 files changed, 52 insertions, 18 deletions

diff --git a/src/gpu/glsl/GrGLSLCaps.cpp b/src/gpu/glsl/GrGLSLCaps.cpp
index 60bea8663a..1f4b855f5d 100755
--- a/src/gpu/glsl/GrGLSLCaps.cpp
+++ b/src/gpu/glsl/GrGLSLCaps.cpp
@@ -29,13 +29,13 @@ GrGLSLCaps::GrGLSLCaps(const GrContextOptions& options) {
     fSampleVariablesSupport = false;
     fSampleMaskOverrideCoverageSupport = false;
     fExternalTextureSupport = false;
-    fBufferTextureSupport = false;
+    fTexelFetchSupport = false;
     fVersionDeclString = nullptr;
     fShaderDerivativeExtensionString = nullptr;
     fFragCoordConventionsExtensionString = nullptr;
     fSecondaryOutputExtensionString = nullptr;
     fExternalTextureExtensionString = nullptr;
-    fBufferTextureExtensionString = nullptr;
+    fTexelBufferExtensionString = nullptr;
     fNoPerspectiveInterpolationExtensionString = nullptr;
     fMultisampleInterpolationExtensionString = nullptr;
     fSampleVariablesExtensionString = nullptr;
@@ -82,7 +82,7 @@ SkString GrGLSLCaps::dump() const {
     r.appendf("Sample mask override coverage support: %s\n", (fSampleMaskOverrideCoverageSupport ?
                                                               "YES" : "NO"));
     r.appendf("External texture support: %s\n", (fExternalTextureSupport ? "YES" : "NO"));
-    r.appendf("Buffer texture support: %s\n", (fBufferTextureSupport ? "YES" : "NO"));
+    r.appendf("texelFetch support: %s\n", (fTexelFetchSupport ? "YES" : "NO"));
     r.appendf("Max VS Samplers: %d\n", fMaxVertexSamplers);
     r.appendf("Max GS Samplers: %d\n", fMaxGeometrySamplers);
     r.appendf("Max FS Samplers: %d\n", fMaxFragmentSamplers);
diff --git a/src/gpu/glsl/GrGLSLCaps.h b/src/gpu/glsl/GrGLSLCaps.h
index a1d458a547..d18b71ae75 100755
--- a/src/gpu/glsl/GrGLSLCaps.h
+++ b/src/gpu/glsl/GrGLSLCaps.h
@@ -66,7 +66,7 @@ public:
 
     bool externalTextureSupport() const { return fExternalTextureSupport; }
 
-    bool bufferTextureSupport() const { return fBufferTextureSupport; }
+    bool texelFetchSupport() const { return fTexelFetchSupport; }
 
     AdvBlendEqInteraction advBlendEqInteraction() const { return fAdvBlendEqInteraction; }
 
@@ -120,9 +120,9 @@ public:
         return fExternalTextureExtensionString;
     }
 
-    const char* bufferTextureExtensionString() const {
-        SkASSERT(this->bufferTextureSupport());
-        return fBufferTextureExtensionString;
+    const char* texelBufferExtensionString() const {
+        SkASSERT(this->texelBufferSupport());
+        return fTexelBufferExtensionString;
     }
 
     const char* noperspectiveInterpolationExtensionString() const {
@@ -194,7 +194,7 @@ private:
     bool fSampleVariablesSupport : 1;
     bool fSampleMaskOverrideCoverageSupport : 1;
     bool fExternalTextureSupport : 1;
-    bool fBufferTextureSupport : 1;
+    bool fTexelFetchSupport : 1;
 
     // Used for specific driver bug work arounds
     bool fCanUseMinAndAbsTogether : 1;
@@ -206,7 +206,7 @@ private:
     const char* fFragCoordConventionsExtensionString;
     const char* fSecondaryOutputExtensionString;
     const char* fExternalTextureExtensionString;
-    const char* fBufferTextureExtensionString;
+    const char* fTexelBufferExtensionString;
     const char* fNoPerspectiveInterpolationExtensionString;
     const char* fMultisampleInterpolationExtensionString;
     const char* fSampleVariablesExtensionString;
diff --git a/src/gpu/glsl/GrGLSLShaderBuilder.cpp b/src/gpu/glsl/GrGLSLShaderBuilder.cpp
index 91a0f9b1b5..1031f84460 100644
--- a/src/gpu/glsl/GrGLSLShaderBuilder.cpp
+++ b/src/gpu/glsl/GrGLSLShaderBuilder.cpp
@@ -93,14 +93,7 @@ void GrGLSLShaderBuilder::appendTextureLookup(SkString* out,
                      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,
@@ -118,6 +111,33 @@ void GrGLSLShaderBuilder::appendTextureLookupAndModulate(const char* modulation,
     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;
diff --git a/src/gpu/glsl/GrGLSLShaderBuilder.h b/src/gpu/glsl/GrGLSLShaderBuilder.h
index 6f8bf68bab..c14df53915 100644
--- a/src/gpu/glsl/GrGLSLShaderBuilder.h
+++ b/src/gpu/glsl/GrGLSLShaderBuilder.h
@@ -34,7 +34,7 @@ public:
                              const char* coordName,
                              GrSLType coordType = kVec2f_GrSLType) const;
 
-    /** Version of above that appends the result to the fragment shader code instead.*/
+    /** Version of above that appends the result to the shader code instead.*/
     void appendTextureLookup(const GrGLSLSampler&,
                              const char* coordName,
                              GrSLType coordType = kVec2f_GrSLType);
@@ -49,6 +49,14 @@ public:
                                         const char* coordName,
                                         GrSLType coordType = kVec2f_GrSLType);
 
+    /** Fetches an unfiltered texel from a sampler at integer coordinates. coordExpr must match the
+        dimensionality of the sampler and must be within the sampler's range. coordExpr is emitted
+        exactly once, so expressions like "idx++" are acceptable. */
+    void appendTexelFetch(SkString* out, const GrGLSLSampler&, const char* coordExpr) const;
+
+    /** Version of above that appends the result to the shader code instead.*/
+    void appendTexelFetch(const GrGLSLSampler&, const char* coordExpr);
+
     /**
     * Adds a #define directive to the top of the shader.
     */
@@ -175,6 +183,12 @@ protected:
 
     void compileAndAppendLayoutQualifiers();
 
+    /* Appends 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".
+     */
+    void appendTextureSwizzle(SkString* out, GrPixelConfig) const;
+
     void nextStage() {
         fShaderStrings.push_back();
         fCompilerStrings.push_back(this->code().c_str());