Refactoring of CPU NormalMap handling out into its own class

src/core/SkLightingShader_NormalSource.cpp

Index: src/core/SkLightingShader_NormalSource.cpp
diff --git a/src/core/SkLightingShader_NormalSource.cpp b/src/core/SkLightingShader_NormalSource.cpp
index 8ad3ed9ec57691811a0580574bbb9908831acda3..a09ff16f35fe2952487b84aa7549423178e97e52 100644
--- a/src/core/SkLightingShader_NormalSource.cpp
+++ b/src/core/SkLightingShader_NormalSource.cpp
@@ -6,6 +6,7 @@
  */
 
 #include "SkBitmapProcShader.h"
+#include "SkBitmapProcState.h"
 #include "SkError.h"
 #include "SkErrorInternals.h"
 #include "SkLightingShader.h"
@@ -41,12 +42,36 @@ public:
                                                    SkSourceGammaTreatment) const override;
 #endif
 
+    SkLightingShader::NormalSource::Provider* asProvider(const SkShader::ContextRec& rec,
+                                                         void* storage) const override;
+
+    size_t providerSize() const override;
+
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(NormalMapSourceImpl)
 
 protected:
     void flatten(SkWriteBuffer& buf) const override;
 
 private:
+
+    class Provider : public SkLightingShader::NormalSource::Provider {
+    public:
+        Provider(const NormalMapSourceImpl& source, SkBitmapProcState* state);
+
+        virtual ~Provider();
+
+        void fillScanLine(int x, int y, SkPoint3 output[], int count) const override;
+
+        int maxCountForFillScanLine(int count) const override;
+    private:
+        const NormalMapSourceImpl& fSource;

[egdaniel, 2016/06/16 13:48:10]

Generally we store pointers here if you just need to this as a const pointer
back to its owner (NormalMapSourceImpl)

[dvonbeck, 2016/06/16 22:05:40]

I did this because it's what LightingShader context does. Should I change this?
Should I change LightingShaderContext?

+        SkBitmapProcState* fState;
+
+        typedef SkLightingShader::NormalSource::Provider INHERITED;
+    };
+
+    bool computeNormTotalInverse(const SkShader::ContextRec& rec, SkMatrix* normTotalInverse) const;
+
     SkBitmap        fNormalMap;
     SkMatrix        fNormLocalMatrix;
     SkVector        fInvNormRotation;
@@ -228,6 +253,91 @@ sk_sp<GrFragmentProcessor> NormalMapSourceImpl::asFragmentProcessor(
 
 ////////////////////////////////////////////////////////////////////////////
 
+NormalMapSourceImpl::Provider::Provider(const NormalMapSourceImpl& source, SkBitmapProcState* state)
+    : fSource(source)
+    , fState(state) {
+    SkASSERT(fState->fPixmap.addr());
+}
+
+NormalMapSourceImpl::Provider::~Provider() {
+    fState->~SkBitmapProcState();
+}
+
+SkLightingShader::NormalSource::Provider* NormalMapSourceImpl::asProvider(
+        const SkShader::ContextRec &rec, void *storage) const {
+    SkMatrix normTotalInv;
+    if (!this->computeNormTotalInverse(rec, &normTotalInv)) {
+        return nullptr;
+    }
+
+    void* stateStorage = (char*)storage + sizeof(Provider);
+    SkBitmapProcState* state = new (stateStorage) SkBitmapProcState(fNormalMap,
+            SkShader::kClamp_TileMode, SkShader::kClamp_TileMode, SkMipMap::DeduceTreatment(rec));
+    SkASSERT(state);
+    if (!state->setup(normTotalInv, *rec.fPaint)) {
+        state->~SkBitmapProcState();
+        return nullptr;
+    }
+
+    return new (storage) Provider(*this, state);
+}
+
+size_t NormalMapSourceImpl::providerSize() const {
+    return sizeof(Provider) + sizeof(SkBitmapProcState);
+}
+
+// TODO: these defines are redundant with the ones in SkLightingShader.cpp, will consolidate in a
+//       future CL when the source of diffuse colores is factored out
+#define TMP_COUNT     16
+#define BUFFER_MAX    (TMP_COUNT * sizeof(uint32_t))
+void NormalMapSourceImpl::Provider::fillScanLine(int x, int y, SkPoint3 output[],
+                                                 int count) const {
+    SkBitmapProcState::MatrixProc   normalMProc = fState->getMatrixProc();
+    SkBitmapProcState::SampleProc32 normalSProc = fState->getSampleProc32();
+
+    uint32_t tmpNormal[BUFFER_MAX];
+    SkPMColor tmpNormal2[2*BUFFER_MAX];
+    normalMProc(*fState, tmpNormal, count, x, y);
+    normalSProc(*fState, tmpNormal, count, tmpNormal2);
+
+    for (int i = 0; i < count; i++) {
+        SkASSERT(0xFF == SkColorGetA(tmpNormal2[i]));  // opaque -> unpremul
+
+        SkPoint3 tempNorm;
+
+        tempNorm.set(SkIntToScalar(SkGetPackedR32(tmpNormal2[i])) - 127.0f,
+                     SkIntToScalar(SkGetPackedG32(tmpNormal2[i])) - 127.0f,
+                     SkIntToScalar(SkGetPackedB32(tmpNormal2[i])) - 127.0f);
+        tempNorm.normalize();
+
+
+        output[i].fX = fSource.fInvNormRotation.fX * tempNorm.fX +
+                       fSource.fInvNormRotation.fY * tempNorm.fY;
+        output[i].fY = -fSource.fInvNormRotation.fY * tempNorm.fX +
+                       fSource.fInvNormRotation.fX * tempNorm.fY;
+        output[i].fZ = tempNorm.fZ;
+    }
+}
+
+int NormalMapSourceImpl::Provider::maxCountForFillScanLine(int count) const {
+    return fState->maxCountForBufferSize(sizeof(uint32_t /*tmpNormal[0]*/) * count);
+}
+
+bool NormalMapSourceImpl::computeNormTotalInverse(const SkShader::ContextRec& rec,
+                                                  SkMatrix* normTotalInverse) const {
+    SkMatrix total;
+    total.setConcat(*rec.fMatrix, fNormLocalMatrix);
+
+    const SkMatrix* m = &total;
+    if (rec.fLocalMatrix) {
+        total.setConcat(*m, *rec.fLocalMatrix);
+        m = &total;
+    }
+    return m->invert(normTotalInverse);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
 sk_sp<SkFlattenable> NormalMapSourceImpl::CreateProc(SkReadBuffer& buf) {
 
     SkMatrix normLocalM;