Added API for Bevel NormalSource.

src/core/SkNormalBevelSource.cpp

Index: src/core/SkNormalBevelSource.cpp
diff --git a/src/core/SkNormalBevelSource.cpp b/src/core/SkNormalBevelSource.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..feccb0cce803db17a3ad7809457a5938fa006c8f
--- /dev/null
+++ b/src/core/SkNormalBevelSource.cpp
@@ -0,0 +1,165 @@
+/*
+ * 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 "SkNormalBevelSource.h"
+
+#include "SkNormalSource.h"
+#include "SkPoint3.h"
+#include "SkReadBuffer.h"
+#include "SkWriteBuffer.h"
+
+#if SK_SUPPORT_GPU
+#include "GrInvariantOutput.h"
+#include "glsl/GrGLSLFragmentProcessor.h"
+#include "glsl/GrGLSLFragmentShaderBuilder.h"
+#include "SkGr.h"
+
+class NormalBevelFP : public GrFragmentProcessor {
+public:
+    NormalBevelFP(SkNormalSource::BevelType type, SkScalar width, SkScalar height)
+        : fType(type)
+        , fWidth(width)
+        , fHeight(height) {
+        this->initClassID<NormalBevelFP>();
+    }
+
+    class GLSLNormalBevelFP : public GrGLSLFragmentProcessor {
+    public:
+        GLSLNormalBevelFP() {
+            fPrevWidth = SkFloatToScalar(0.0f);
+            fPrevHeight = SkFloatToScalar(0.0f);
+        }
+
+        void emitCode(EmitArgs& args) override {
+            GrGLSLFragmentBuilder* fragBuilder = args.fFragBuilder;
+            GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
+
+            const char* widthUniName = nullptr;
+            fWidthUni = uniformHandler->addUniform(kFragment_GrShaderFlag, kFloat_GrSLType,
+                    kDefault_GrSLPrecision, "Width", &widthUniName);
+
+            const char* heightUniName = nullptr;
+            fHeightUni = uniformHandler->addUniform(kFragment_GrShaderFlag, kFloat_GrSLType,
+                    kDefault_GrSLPrecision, "Height", &heightUniName);
+
+            fragBuilder->codeAppendf("%s = vec4(0, 0, 1, 0);", args.fOutputColor);
+        }
+
+        static void GenKey(const GrProcessor& proc, const GrGLSLCaps&,
+                           GrProcessorKeyBuilder* b) {
+            const NormalBevelFP& fp = proc.cast<NormalBevelFP>();
+            b->add32(static_cast<int>(fp.fType));
+        }
+
+    protected:
+        void onSetData(const GrGLSLProgramDataManager& pdman, const GrProcessor& proc) override {
+            const NormalBevelFP& normalBevelFP = proc.cast<NormalBevelFP>();
+
+            if (fPrevWidth  != normalBevelFP.fWidth) {
+                pdman.set1f(fWidthUni, normalBevelFP.fWidth);
+                fPrevWidth = normalBevelFP.fWidth;
+            }
+            if (fPrevHeight != normalBevelFP.fHeight) {
+                pdman.set1f(fHeightUni, normalBevelFP.fHeight);
+                fPrevHeight = normalBevelFP.fHeight;
+            }
+        }
+
+    private:
+        SkScalar fPrevWidth;
+        GrGLSLProgramDataManager::UniformHandle fWidthUni;
+
+        SkScalar fPrevHeight;
+        GrGLSLProgramDataManager::UniformHandle fHeightUni;
+    };
+
+    void onGetGLSLProcessorKey(const GrGLSLCaps& caps, GrProcessorKeyBuilder* b) const override {
+        GLSLNormalBevelFP::GenKey(*this, caps, b);
+    }
+
+    const char* name() const override { return "NormalBevelFP"; }
+
+    void onComputeInvariantOutput(GrInvariantOutput* inout) const override {
+        inout->setToUnknown(GrInvariantOutput::ReadInput::kWillNot_ReadInput);
+    }
+
+private:
+    GrGLSLFragmentProcessor* onCreateGLSLInstance() const override { return new GLSLNormalBevelFP; }
+
+    bool onIsEqual(const GrFragmentProcessor& proc) const override {
+        const NormalBevelFP& normalBevelFP = proc.cast<NormalBevelFP>();
+        return fType   == normalBevelFP.fType &&
+               fWidth  == normalBevelFP.fWidth &&
+               fHeight == normalBevelFP.fHeight;
+    }
+
+    SkNormalSource::BevelType fType;
+    SkScalar fWidth;
+    SkScalar fHeight;
+};
+
+sk_sp<GrFragmentProcessor> SkNormalBevelSourceImpl::asFragmentProcessor(
+        const SkShader::AsFPArgs&) const {
+
+    return sk_make_sp<NormalBevelFP>(fType, fWidth, fHeight);
+}
+
+#endif // SK_SUPPORT_GPU
+
+////////////////////////////////////////////////////////////////////////////
+
+SkNormalBevelSourceImpl::Provider::Provider() {}
+
+SkNormalBevelSourceImpl::Provider::~Provider() {}
+
+SkNormalSource::Provider* SkNormalBevelSourceImpl::asProvider(const SkShader::ContextRec &rec,
+                                                            void *storage) const {
+    return new (storage) Provider();
+}
+
+size_t SkNormalBevelSourceImpl::providerSize(const SkShader::ContextRec&) const {
+    return sizeof(Provider);
+}
+
+void SkNormalBevelSourceImpl::Provider::fillScanLine(int x, int y, SkPoint3 output[],
+                                                   int count) const {
+    for (int i = 0; i < count; i++) {
+        output[i] = {0.0f, 0.0f, 1.0f};
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+sk_sp<SkFlattenable> SkNormalBevelSourceImpl::CreateProc(SkReadBuffer& buf) {
+
+    auto type = static_cast<SkNormalSource::BevelType>(buf.readInt());
+    SkScalar width = buf.readScalar();
+    SkScalar height = buf.readScalar();
+
+    return sk_make_sp<SkNormalBevelSourceImpl>(type, width, height);
+}
+
+void SkNormalBevelSourceImpl::flatten(SkWriteBuffer& buf) const {
+    this->INHERITED::flatten(buf);
+
+    buf.writeInt(static_cast<int>(fType));
+    buf.writeScalar(fWidth);
+    buf.writeScalar(fHeight);
+}
+
+////////////////////////////////////////////////////////////////////////////
+
+sk_sp<SkNormalSource> SkNormalSource::MakeBevel(BevelType type, SkScalar width, SkScalar height) {
+    /* TODO make sure this checks are tolerant enough to account for loss of conversion when GPUs
+       use 16-bit float types. We don't want to assume stuff is non-zero on the GPU and be wrong.*/
+    SkASSERT(width > 0.0f && !SkScalarNearlyZero(width));
+    if (SkScalarNearlyZero(height)) {
+        return SkNormalSource::MakeFlat();
+    }
+
+    return sk_make_sp<SkNormalBevelSourceImpl>(type, width, height);
+}