Refactoring of CPU NormalMap handling out into its own class

src/core/SkNormalSource.cpp

Index: src/core/SkNormalSource.cpp
diff --git a/src/core/SkLightingShader_NormalSource.cpp b/src/core/SkNormalSource.cpp
similarity index 54%
rename from src/core/SkLightingShader_NormalSource.cpp
rename to src/core/SkNormalSource.cpp
index b96b1bf083c314b4f6e33f94bb21b5c0c5c0fb59..cadf47e29ce5b57dfa96acf13136541a6515d4dd 100644
--- a/src/core/SkLightingShader_NormalSource.cpp
+++ b/src/core/SkNormalSource.cpp
@@ -6,32 +6,24 @@
  */
 
 #include "SkBitmapProcShader.h"
+#include "SkBitmapProcState.h"
 #include "SkError.h"
 #include "SkErrorInternals.h"
 #include "SkLightingShader.h"
+#include "SkNormalSource.h"
 #include "SkReadBuffer.h"
 #include "SkWriteBuffer.h"
 
 // Genretating vtable
-SkLightingShader::NormalSource::~NormalSource() {}
+SkNormalSource::~SkNormalSource() {}
 
 ///////////////////////////////////////////////////////////////////////////////
 
-class NormalMapSourceImpl : public SkLightingShader::NormalSource {
+class NormalMapSourceImpl : public SkNormalSource {
 public:
-    NormalMapSourceImpl(const SkBitmap &normal, const SkVector &invNormRotation,
-                        const SkMatrix *normLocalM)
-        : fNormalMap(normal)
-        , fInvNormRotation(invNormRotation) {
-
-        if (normLocalM) {
-            fNormLocalMatrix = *normLocalM;
-        } else {
-            fNormLocalMatrix.reset();
-        }
-        // Pre-cache so future calls to fNormLocalMatrix.getType() are threadsafe.
-        (void)fNormLocalMatrix.getType();
-    }
+    NormalMapSourceImpl(sk_sp<SkShader> bitmapShader, const SkVector &invNormRotation)
+        : fBitmapShader(std::move(bitmapShader))
+        , fInvNormRotation(invNormRotation) {}
 
 #if SK_SUPPORT_GPU
     sk_sp<GrFragmentProcessor> asFragmentProcessor(GrContext*,
@@ -41,19 +33,38 @@ public:
                                                    SkSourceGammaTreatment) const override;
 #endif
 
+    SkNormalSource::Provider* asProvider(const SkShader::ContextRec& rec,
+                                                         void* storage) const override;
+
+    size_t providerSize(const SkShader::ContextRec& rec) const override;
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(NormalMapSourceImpl)
 
 protected:
     void flatten(SkWriteBuffer& buf) const override;
 
+    bool computeNormTotalInverse(const SkShader::ContextRec& rec, SkMatrix* normTotalInverse) const;
+
 private:
-    SkBitmap        fNormalMap;
-    SkMatrix        fNormLocalMatrix;
+    class Provider : public SkNormalSource::Provider {
+    public:
+        Provider(const NormalMapSourceImpl& source, SkShader::Context* fBitmapContext);
+
+        virtual ~Provider();
+
+        void fillScanLine(int x, int y, SkPoint3 output[], int count) const override;
+    private:
+        const NormalMapSourceImpl& fSource;
+        SkShader::Context* fBitmapContext;
+
+        typedef SkNormalSource::Provider INHERITED;
+    };
+
+    sk_sp<SkShader> fBitmapShader;
     SkVector        fInvNormRotation;
 
-    friend class SkLightingShader::NormalSource;
+    friend class SkNormalSource;
 
-    typedef SkLightingShader::NormalSource INHERITED;
+    typedef SkNormalSource INHERITED;
 };
 
 ////////////////////////////////////////////////////////////////////////////
@@ -69,13 +80,9 @@ private:
 
 class NormalMapFP : public GrFragmentProcessor {
 public:
-    NormalMapFP(GrTexture* normal, const SkMatrix& normMatrix, const GrTextureParams& normParams,
-                const SkVector& invNormRotation)
-        : fNormDeviceTransform(kLocal_GrCoordSet, normMatrix, normal, normParams.filterMode())
-        , fNormalTextureAccess(normal, normParams)
-        , fInvNormRotation(invNormRotation) {
-        this->addCoordTransform(&fNormDeviceTransform);
-        this->addTextureAccess(&fNormalTextureAccess);
+    NormalMapFP(sk_sp<GrFragmentProcessor> bitmapFP, const SkVector& invNormRotation)
+        : fInvNormRotation(invNormRotation) {
+        this->registerChildProcessor(bitmapFP);
 
         this->initClassID<NormalMapFP>();
     }
@@ -97,13 +104,10 @@ public:
                                                    kVec2f_GrSLType, kDefault_GrSLPrecision,
                                                    "Xform", &xformUniName);
 
-            fragBuilder->codeAppend("vec4 normalColor = ");
-            fragBuilder->appendTextureLookup(args.fTexSamplers[0],
-                                             args.fCoords[0].c_str(),
-                                             args.fCoords[0].getType());
-            fragBuilder->codeAppend(";");
-
-            fragBuilder->codeAppend("vec3 normal = normalColor.rgb - vec3(0.5);");
+            SkString dstNormalColorName("dstNormalColor");
+            this->emitChild(0, nullptr, &dstNormalColorName, args);
+            fragBuilder->codeAppendf("vec3 normal = %s.rgb - vec3(0.5);",
+                                     dstNormalColorName.c_str());
 
             // TODO: inverse map the light direction vectors in the vertex shader rather than
             // transforming all the normals here!
@@ -153,40 +157,12 @@ private:
 
     bool onIsEqual(const GrFragmentProcessor& proc) const override {
         const NormalMapFP& normalMapFP = proc.cast<NormalMapFP>();
-        return fNormDeviceTransform == normalMapFP.fNormDeviceTransform &&
-               fNormalTextureAccess == normalMapFP.fNormalTextureAccess &&
-               fInvNormRotation     == normalMapFP.fInvNormRotation;
+        return fInvNormRotation == normalMapFP.fInvNormRotation;
     }
 
-    GrCoordTransform fNormDeviceTransform;
-    GrTextureAccess  fNormalTextureAccess;
-    SkVector         fInvNormRotation;
+    SkVector fInvNormRotation;
 };
 
-// TODO same code at SkLightingShader.cpp. Refactor to common source!
-static bool make_mat(const SkBitmap& bm,
-                     const SkMatrix& localMatrix1,
-                     const SkMatrix* localMatrix2,
-                     SkMatrix* result) {
-
-    result->setIDiv(bm.width(), bm.height());
-
-    SkMatrix lmInverse;
-    if (!localMatrix1.invert(&lmInverse)) {
-        return false;
-    }
-    if (localMatrix2) {
-        SkMatrix inv;
-        if (!localMatrix2->invert(&inv)) {
-            return false;
-        }
-        lmInverse.postConcat(inv);
-    }
-    result->preConcat(lmInverse);
-
-    return true;
-}
-
 sk_sp<GrFragmentProcessor> NormalMapSourceImpl::asFragmentProcessor(
                                                      GrContext *context,
                                                      const SkMatrix &viewM,
@@ -194,96 +170,132 @@ sk_sp<GrFragmentProcessor> NormalMapSourceImpl::asFragmentProcessor(
                                                      SkFilterQuality filterQuality,
                                                      SkSourceGammaTreatment gammaTreatment) const {
 
-    // TODO Here, the old code was checking that diffuse map and normal map are same size, that
-    //      will be addressed when diffuse maps are factored out of SkLightingShader in a future CL
+    sk_sp<GrFragmentProcessor> bitmapFP = fBitmapShader->asFragmentProcessor(context, viewM,
+            localMatrix, filterQuality, gammaTreatment);
+
+    return sk_make_sp<NormalMapFP>(std::move(bitmapFP), fInvNormRotation);
+}
+
+#endif // SK_SUPPORT_GPU
+
+////////////////////////////////////////////////////////////////////////////
+
+NormalMapSourceImpl::Provider::Provider(const NormalMapSourceImpl& source,
+                                        SkShader::Context* bitmapContext)
+    : fSource(source)
+    , fBitmapContext(bitmapContext) {
+}
+
+NormalMapSourceImpl::Provider::~Provider() {
+    fBitmapContext->~Context();
+}
 
-    SkMatrix normM;
-    if (!make_mat(fNormalMap, fNormLocalMatrix, localMatrix, &normM)) {
+SkNormalSource::Provider* NormalMapSourceImpl::asProvider(
+        const SkShader::ContextRec &rec, void *storage) const {
+    SkMatrix normTotalInv;
+    if (!this->computeNormTotalInverse(rec, &normTotalInv)) {
         return nullptr;
     }
 
-    bool doBicubic;
-    GrTextureParams::FilterMode normFilterMode = GrSkFilterQualityToGrFilterMode(
-            SkTMin(filterQuality, kMedium_SkFilterQuality),
-            viewM,
-            fNormLocalMatrix,
-            &doBicubic);
-    SkASSERT(!doBicubic);
-
-    // TODO: support other tile modes
-    GrTextureParams normParams(SkShader::kClamp_TileMode, normFilterMode);
-    SkAutoTUnref<GrTexture> normalTexture(GrRefCachedBitmapTexture(context,
-                                                                   fNormalMap,
-                                                                   normParams,
-                                                                   gammaTreatment));
-    if (!normalTexture) {
-        SkErrorInternals::SetError(kInternalError_SkError, "Couldn't convert bitmap to texture.");
+    void* bitmapContextStorage = (char*)storage + sizeof(Provider);
+    SkShader::Context* context = fBitmapShader->createContext(rec, bitmapContextStorage);
+    if (!context) {
         return nullptr;
     }
 
-    return sk_make_sp<NormalMapFP>(normalTexture, normM, normParams, fInvNormRotation);
+    return new (storage) Provider(*this, context);
 }
 
-#endif // SK_SUPPORT_GPU
-
-////////////////////////////////////////////////////////////////////////////
+size_t NormalMapSourceImpl::providerSize(const SkShader::ContextRec& rec) const {
+    return sizeof(Provider) + fBitmapShader->contextSize(rec);
+}
 
-sk_sp<SkFlattenable> NormalMapSourceImpl::CreateProc(SkReadBuffer& buf) {
+bool NormalMapSourceImpl::computeNormTotalInverse(const SkShader::ContextRec& rec,
+                                                  SkMatrix* normTotalInverse) const {
+    SkMatrix total;
+    total.setConcat(*rec.fMatrix, fBitmapShader->getLocalMatrix());
 
-    SkMatrix normLocalM;
-    bool hasNormLocalM = buf.readBool();
-    if (hasNormLocalM) {
-        buf.readMatrix(&normLocalM);
-    } else {
-        normLocalM.reset();
+    const SkMatrix* m = &total;
+    if (rec.fLocalMatrix) {
+        total.setConcat(*m, *rec.fLocalMatrix);
+        m = &total;
     }
+    return m->invert(normTotalInverse);
+}
 
-    SkBitmap normal;
-    if (!buf.readBitmap(&normal)) {
-        return nullptr;
-    }
-    normal.setImmutable();
+#define BUFFER_MAX 16
+void NormalMapSourceImpl::Provider::fillScanLine(int x, int y, SkPoint3 output[],
+                                                 int count) const {
+    SkPMColor tmpNormalColors[BUFFER_MAX];
+
+    do {
+        int n = SkTMin(count, BUFFER_MAX);
+
+        fBitmapContext->shadeSpan(x, y, tmpNormalColors, n);
+
+        for (int i = 0; i < n; i++) {
+            SkPoint3 tempNorm;
+
+            tempNorm.set(SkIntToScalar(SkGetPackedR32(tmpNormalColors[i])) - 127.0f,
+                         SkIntToScalar(SkGetPackedG32(tmpNormalColors[i])) - 127.0f,
+                         SkIntToScalar(SkGetPackedB32(tmpNormalColors[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;
+        }
+
+        output += n;
+        x += n;
+        count -= n;
+    } while (count > 0);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+sk_sp<SkFlattenable> NormalMapSourceImpl::CreateProc(SkReadBuffer& buf) {
+
+    sk_sp<SkShader> bitmapShader = buf.readFlattenable<SkShader>();
 
     SkVector invNormRotation = {1,0};
     if (!buf.isVersionLT(SkReadBuffer::kLightingShaderWritesInvNormRotation)) {
         invNormRotation = buf.readPoint();
     }
 
-    return sk_make_sp<NormalMapSourceImpl>(normal, invNormRotation, &normLocalM);
+    return sk_make_sp<NormalMapSourceImpl>(std::move(bitmapShader), invNormRotation);
 }
 
 void NormalMapSourceImpl::flatten(SkWriteBuffer& buf) const {
     this->INHERITED::flatten(buf);
 
-    bool hasNormLocalM = !fNormLocalMatrix.isIdentity();
-    buf.writeBool(hasNormLocalM);
-    if (hasNormLocalM) {
-        buf.writeMatrix(fNormLocalMatrix);
-    }
-
-    buf.writeBitmap(fNormalMap);
+    buf.writeFlattenable(fBitmapShader.get());
     buf.writePoint(fInvNormRotation);
 }
 
 ////////////////////////////////////////////////////////////////////////////
 
-sk_sp<SkLightingShader::NormalSource> SkLightingShader::NormalSource::MakeMap(
+sk_sp<SkNormalSource> SkNormalSource::MakeMap(
         const SkBitmap &normal, const SkVector &invNormRotation, const SkMatrix *normLocalM) {
 
-    // TODO not checking normal and diffuse maps to be same size, will be addressed when diffuse
-    //      maps are factored out of SkLightingShader in a future CL
     if (normal.isNull() || SkBitmapProcShader::BitmapIsTooBig(normal)) {
         return nullptr;
     }
 
     SkASSERT(SkScalarNearlyEqual(invNormRotation.lengthSqd(), SK_Scalar1));
 
-    return sk_make_sp<NormalMapSourceImpl>(normal, invNormRotation, normLocalM);
+    // TODO: support other tile modes
+    sk_sp<SkShader> bitmapShader = SkMakeBitmapShader(normal, SkShader::kClamp_TileMode,
+            SkShader::kClamp_TileMode, normLocalM, nullptr);
+
+    return sk_make_sp<NormalMapSourceImpl>(std::move(bitmapShader), invNormRotation);
 }
 
 ////////////////////////////////////////////////////////////////////////////
 
-SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_START(SkLightingShader::NormalSource)
+SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_START(SkNormalSource)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(NormalMapSourceImpl)
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_END