1 files changed, 136 insertions, 0 deletions
diff --git a/src/gpu/effects/GrGammaEffect.cpp b/src/gpu/effects/GrGammaEffect.cpp
new file mode 100644
index 0000000000..b2aa48aad2
--- /dev/null
+++ b/src/gpu/effects/GrGammaEffect.cpp
@@ -0,0 +1,136 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "GrGammaEffect.h"
+
+#include "GrContext.h"
+#include "GrCoordTransform.h"
+#include "GrFragmentProcessor.h"
+#include "GrInvariantOutput.h"
+#include "GrProcessor.h"
+#include "glsl/GrGLSLFragmentProcessor.h"
+#include "glsl/GrGLSLFragmentShaderBuilder.h"
+
+class GrGLGammaEffect : public GrGLSLFragmentProcessor {
+public:
+    void emitCode(EmitArgs& args) override {
+        const GrGammaEffect& ge = args.fFp.cast<GrGammaEffect>();
+        GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
+        GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
+
+        const char* gammaUniName = nullptr;
+        if (!ge.gammaIsSRGB()) {
+            fGammaUni = uniformHandler->addUniform(kFragment_GrShaderFlag, kFloat_GrSLType,
+                                                   kDefault_GrSLPrecision, "Gamma", &gammaUniName);
+        }
+
+        GrGLSLShaderVar tmpVar("tmpColor", kVec4f_GrSLType, 0, kHigh_GrSLPrecision);
+        SkString tmpDecl;
+        tmpVar.appendDecl(args.fGLSLCaps, &tmpDecl);
+
+        SkString srgbFuncName;
+        if (ge.gammaIsSRGB()) {
+            static const GrGLSLShaderVar gSrgbArgs[] = {
+                GrGLSLShaderVar("x", kFloat_GrSLType),
+            };
+
+            fragBuilder->emitFunction(kFloat_GrSLType,
+                                        "linear_to_srgb",
+                                        SK_ARRAY_COUNT(gSrgbArgs),
+                                        gSrgbArgs,
+                                        "return (x <= 0.0031308) ? (x * 12.92) "
+                                        ": (1.055 * pow(x, 0.416666667) - 0.055);",
+                                        &srgbFuncName);
+        }
+
+        fragBuilder->codeAppendf("%s;", tmpDecl.c_str());
+
+        fragBuilder->codeAppendf("%s = ", tmpVar.c_str());
+        fragBuilder->appendTextureLookup(args.fTexSamplers[0], args.fCoords[0].c_str(),
+                                            args.fCoords[0].getType());
+        fragBuilder->codeAppend(";");
+
+        if (ge.gammaIsSRGB()) {
+            fragBuilder->codeAppendf("%s = vec4(%s(%s.r), %s(%s.g), %s(%s.b), %s.a);",
+                                        args.fOutputColor,
+                                        srgbFuncName.c_str(), tmpVar.c_str(),
+                                        srgbFuncName.c_str(), tmpVar.c_str(),
+                                        srgbFuncName.c_str(), tmpVar.c_str(),
+                                        tmpVar.c_str());
+        } else {
+            fragBuilder->codeAppendf("%s = vec4(pow(%s.rgb, vec3(%s)), %s.a);",
+                                        args.fOutputColor, tmpVar.c_str(), gammaUniName,
+                                        tmpVar.c_str());
+        }
+    }
+
+    void onSetData(const GrGLSLProgramDataManager& pdman, const GrProcessor& proc) override {
+        const GrGammaEffect& ge = proc.cast<GrGammaEffect>();
+        if (!ge.gammaIsSRGB()) {
+            pdman.set1f(fGammaUni, ge.gamma());
+        }
+    }
+
+    static inline void GenKey(const GrProcessor& processor, const GrGLSLCaps&,
+                              GrProcessorKeyBuilder* b) {
+        const GrGammaEffect& ge = processor.cast<GrGammaEffect>();
+        uint32_t key = ge.gammaIsSRGB() ? 0x1 : 0x0;
+        b->add32(key);
+    }
+
+private:
+    GrGLSLProgramDataManager::UniformHandle fGammaUni;
+
+    typedef GrGLSLFragmentProcessor INHERITED;
+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+GrGammaEffect::GrGammaEffect(GrTexture* texture, SkScalar gamma)
+    : INHERITED(texture, GrCoordTransform::MakeDivByTextureWHMatrix(texture)) {
+    this->initClassID<GrGammaEffect>();
+
+    fGamma = gamma;
+    fGammaIsSRGB = SkScalarNearlyEqual(gamma, 1.0f / 2.2f);
+}
+
+bool GrGammaEffect::onIsEqual(const GrFragmentProcessor& s) const {
+    const GrGammaEffect& other = s.cast<GrGammaEffect>();
+    return
+        other.fGammaIsSRGB == fGammaIsSRGB &&
+        other.fGamma == fGamma;
+}
+
+void GrGammaEffect::onComputeInvariantOutput(GrInvariantOutput* inout) const {
+    inout->setToUnknown(GrInvariantOutput::kWill_ReadInput);
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrGammaEffect);
+
+const GrFragmentProcessor* GrGammaEffect::TestCreate(GrProcessorTestData* d) {
+    // We want to be sure and test sRGB sometimes
+    bool srgb = d->fRandom->nextBool();
+    return new GrGammaEffect(d->fTextures[GrProcessorUnitTest::kSkiaPMTextureIdx],
+                             srgb ? 1.0f / 2.2f : d->fRandom->nextRangeScalar(0.5f, 2.0f));
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+void GrGammaEffect::onGetGLSLProcessorKey(const GrGLSLCaps& caps,
+                                               GrProcessorKeyBuilder* b) const {
+    GrGLGammaEffect::GenKey(*this, caps, b);
+}
+
+GrGLSLFragmentProcessor* GrGammaEffect::onCreateGLSLInstance() const {
+    return new GrGLGammaEffect();
+}
+
+const GrFragmentProcessor* GrGammaEffect::Create(GrTexture* texture, SkScalar gamma) {
+    return new GrGammaEffect(texture, gamma);
+}