michael@0: /*
michael@0:  * Copyright 2013 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #include "SkArithmeticMode.h"
michael@0: #include "SkColorPriv.h"
michael@0: #include "SkReadBuffer.h"
michael@0: #include "SkWriteBuffer.h"
michael@0: #include "SkString.h"
michael@0: #include "SkUnPreMultiply.h"
michael@0: #if SK_SUPPORT_GPU
michael@0: #include "GrContext.h"
michael@0: #include "GrCoordTransform.h"
michael@0: #include "gl/GrGLEffect.h"
michael@0: #include "GrTBackendEffectFactory.h"
michael@0: #endif
michael@0: 
michael@0: static const bool gUseUnpremul = false;
michael@0: 
michael@0: class SkArithmeticMode_scalar : public SkXfermode {
michael@0: public:
michael@0:     static SkArithmeticMode_scalar* Create(SkScalar k1, SkScalar k2, SkScalar k3, SkScalar k4) {
michael@0:         return SkNEW_ARGS(SkArithmeticMode_scalar, (k1, k2, k3, k4));
michael@0:     }
michael@0: 
michael@0:     virtual void xfer32(SkPMColor dst[], const SkPMColor src[], int count,
michael@0:                         const SkAlpha aa[]) const SK_OVERRIDE;
michael@0: 
michael@0:     SK_TO_STRING_OVERRIDE()
michael@0:     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkArithmeticMode_scalar)
michael@0: 
michael@0: #if SK_SUPPORT_GPU
michael@0:     virtual bool asNewEffect(GrEffectRef** effect, GrTexture* background) const SK_OVERRIDE;
michael@0: #endif
michael@0: 
michael@0: private:
michael@0:     SkArithmeticMode_scalar(SkScalar k1, SkScalar k2, SkScalar k3, SkScalar k4) {
michael@0:         fK[0] = k1;
michael@0:         fK[1] = k2;
michael@0:         fK[2] = k3;
michael@0:         fK[3] = k4;
michael@0:     }
michael@0: 
michael@0:     SkArithmeticMode_scalar(SkReadBuffer& buffer) : INHERITED(buffer) {
michael@0:         fK[0] = buffer.readScalar();
michael@0:         fK[1] = buffer.readScalar();
michael@0:         fK[2] = buffer.readScalar();
michael@0:         fK[3] = buffer.readScalar();
michael@0:     }
michael@0: 
michael@0:     virtual void flatten(SkWriteBuffer& buffer) const SK_OVERRIDE {
michael@0:         INHERITED::flatten(buffer);
michael@0:         buffer.writeScalar(fK[0]);
michael@0:         buffer.writeScalar(fK[1]);
michael@0:         buffer.writeScalar(fK[2]);
michael@0:         buffer.writeScalar(fK[3]);
michael@0:     }
michael@0:     SkScalar fK[4];
michael@0: 
michael@0:     typedef SkXfermode INHERITED;
michael@0: };
michael@0: 
michael@0: static int pinToByte(int value) {
michael@0:     if (value < 0) {
michael@0:         value = 0;
michael@0:     } else if (value > 255) {
michael@0:         value = 255;
michael@0:     }
michael@0:     return value;
michael@0: }
michael@0: 
michael@0: static int arith(SkScalar k1, SkScalar k2, SkScalar k3, SkScalar k4,
michael@0:                  int src, int dst) {
michael@0:     SkScalar result = SkScalarMul(k1, src * dst) +
michael@0:                       SkScalarMul(k2, src) +
michael@0:                       SkScalarMul(k3, dst) +
michael@0:                       k4;
michael@0:     int res = SkScalarRoundToInt(result);
michael@0:     return pinToByte(res);
michael@0: }
michael@0: 
michael@0: static int blend(int src, int dst, int scale) {
michael@0:     return dst + ((src - dst) * scale >> 8);
michael@0: }
michael@0: 
michael@0: static bool needsUnpremul(int alpha) {
michael@0:     return 0 != alpha && 0xFF != alpha;
michael@0: }
michael@0: 
michael@0: void SkArithmeticMode_scalar::xfer32(SkPMColor dst[], const SkPMColor src[],
michael@0:                                  int count, const SkAlpha aaCoverage[]) const {
michael@0:     SkScalar k1 = fK[0] / 255;
michael@0:     SkScalar k2 = fK[1];
michael@0:     SkScalar k3 = fK[2];
michael@0:     SkScalar k4 = fK[3] * 255;
michael@0: 
michael@0:     for (int i = 0; i < count; ++i) {
michael@0:         if ((NULL == aaCoverage) || aaCoverage[i]) {
michael@0:             SkPMColor sc = src[i];
michael@0:             SkPMColor dc = dst[i];
michael@0: 
michael@0:             int a, r, g, b;
michael@0: 
michael@0:             if (gUseUnpremul) {
michael@0:                 int sa = SkGetPackedA32(sc);
michael@0:                 int da = SkGetPackedA32(dc);
michael@0: 
michael@0:                 int srcNeedsUnpremul = needsUnpremul(sa);
michael@0:                 int dstNeedsUnpremul = needsUnpremul(da);
michael@0: 
michael@0:                 if (!srcNeedsUnpremul && !dstNeedsUnpremul) {
michael@0:                     a = arith(k1, k2, k3, k4, sa, da);
michael@0:                     r = arith(k1, k2, k3, k4, SkGetPackedR32(sc), SkGetPackedR32(dc));
michael@0:                     g = arith(k1, k2, k3, k4, SkGetPackedG32(sc), SkGetPackedG32(dc));
michael@0:                     b = arith(k1, k2, k3, k4, SkGetPackedB32(sc), SkGetPackedB32(dc));
michael@0:                 } else {
michael@0:                     int sr = SkGetPackedR32(sc);
michael@0:                     int sg = SkGetPackedG32(sc);
michael@0:                     int sb = SkGetPackedB32(sc);
michael@0:                     if (srcNeedsUnpremul) {
michael@0:                         SkUnPreMultiply::Scale scale = SkUnPreMultiply::GetScale(sa);
michael@0:                         sr = SkUnPreMultiply::ApplyScale(scale, sr);
michael@0:                         sg = SkUnPreMultiply::ApplyScale(scale, sg);
michael@0:                         sb = SkUnPreMultiply::ApplyScale(scale, sb);
michael@0:                     }
michael@0: 
michael@0:                     int dr = SkGetPackedR32(dc);
michael@0:                     int dg = SkGetPackedG32(dc);
michael@0:                     int db = SkGetPackedB32(dc);
michael@0:                     if (dstNeedsUnpremul) {
michael@0:                         SkUnPreMultiply::Scale scale = SkUnPreMultiply::GetScale(da);
michael@0:                         dr = SkUnPreMultiply::ApplyScale(scale, dr);
michael@0:                         dg = SkUnPreMultiply::ApplyScale(scale, dg);
michael@0:                         db = SkUnPreMultiply::ApplyScale(scale, db);
michael@0:                     }
michael@0: 
michael@0:                     a = arith(k1, k2, k3, k4, sa, da);
michael@0:                     r = arith(k1, k2, k3, k4, sr, dr);
michael@0:                     g = arith(k1, k2, k3, k4, sg, dg);
michael@0:                     b = arith(k1, k2, k3, k4, sb, db);
michael@0:                 }
michael@0:             } else {
michael@0:                 a = arith(k1, k2, k3, k4, SkGetPackedA32(sc), SkGetPackedA32(dc));
michael@0:                 r = arith(k1, k2, k3, k4, SkGetPackedR32(sc), SkGetPackedR32(dc));
michael@0:                 r = SkMin32(r, a);
michael@0:                 g = arith(k1, k2, k3, k4, SkGetPackedG32(sc), SkGetPackedG32(dc));
michael@0:                 g = SkMin32(g, a);
michael@0:                 b = arith(k1, k2, k3, k4, SkGetPackedB32(sc), SkGetPackedB32(dc));
michael@0:                 b = SkMin32(b, a);
michael@0:             }
michael@0: 
michael@0:             // apply antialias coverage if necessary
michael@0:             if (aaCoverage && 0xFF != aaCoverage[i]) {
michael@0:                 int scale = aaCoverage[i] + (aaCoverage[i] >> 7);
michael@0:                 a = blend(a, SkGetPackedA32(sc), scale);
michael@0:                 r = blend(r, SkGetPackedR32(sc), scale);
michael@0:                 g = blend(g, SkGetPackedG32(sc), scale);
michael@0:                 b = blend(b, SkGetPackedB32(sc), scale);
michael@0:             }
michael@0: 
michael@0:             // turn the result back into premul
michael@0:             if (gUseUnpremul && (0xFF != a)) {
michael@0:                 int scale = a + (a >> 7);
michael@0:                 r = SkAlphaMul(r, scale);
michael@0:                 g = SkAlphaMul(g, scale);
michael@0:                 b = SkAlphaMul(b, scale);
michael@0:             }
michael@0:             dst[i] = SkPackARGB32(a, r, g, b);
michael@0:         }
michael@0:     }
michael@0: }
michael@0: 
michael@0: #ifndef SK_IGNORE_TO_STRING
michael@0: void SkArithmeticMode_scalar::toString(SkString* str) const {
michael@0:     str->append("SkArithmeticMode_scalar: ");
michael@0:     for (int i = 0; i < 4; ++i) {
michael@0:         str->appendScalar(fK[i]);
michael@0:         if (i < 3) {
michael@0:             str->append(" ");
michael@0:         }
michael@0:     }
michael@0: }
michael@0: #endif
michael@0: 
michael@0: ///////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: static bool fitsInBits(SkScalar x, int bits) {
michael@0:     return SkScalarAbs(x) < (1 << (bits - 1));
michael@0: }
michael@0: 
michael@0: #if 0 // UNUSED
michael@0: static int32_t toDot8(SkScalar x) {
michael@0:     return (int32_t)(x * 256);
michael@0: }
michael@0: #endif
michael@0: 
michael@0: SkXfermode* SkArithmeticMode::Create(SkScalar k1, SkScalar k2,
michael@0:                                      SkScalar k3, SkScalar k4) {
michael@0:     if (fitsInBits(k1, 8) && fitsInBits(k2, 16) &&
michael@0:         fitsInBits(k2, 16) && fitsInBits(k2, 24)) {
michael@0: 
michael@0: #if 0 // UNUSED
michael@0:         int32_t i1 = toDot8(k1);
michael@0:         int32_t i2 = toDot8(k2);
michael@0:         int32_t i3 = toDot8(k3);
michael@0:         int32_t i4 = toDot8(k4);
michael@0:         if (i1) {
michael@0:             return SkNEW_ARGS(SkArithmeticMode_quad, (i1, i2, i3, i4));
michael@0:         }
michael@0:         if (0 == i2) {
michael@0:             return SkNEW_ARGS(SkArithmeticMode_dst, (i3, i4));
michael@0:         }
michael@0:         if (0 == i3) {
michael@0:             return SkNEW_ARGS(SkArithmeticMode_src, (i2, i4));
michael@0:         }
michael@0:         return SkNEW_ARGS(SkArithmeticMode_linear, (i2, i3, i4));
michael@0: #endif
michael@0:     }
michael@0:     return SkArithmeticMode_scalar::Create(k1, k2, k3, k4);
michael@0: }
michael@0: 
michael@0: 
michael@0: //////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: #if SK_SUPPORT_GPU
michael@0: 
michael@0: class GrGLArithmeticEffect : public GrGLEffect {
michael@0: public:
michael@0:     GrGLArithmeticEffect(const GrBackendEffectFactory&, const GrDrawEffect&);
michael@0:     virtual ~GrGLArithmeticEffect();
michael@0: 
michael@0:     virtual void emitCode(GrGLShaderBuilder*,
michael@0:                           const GrDrawEffect&,
michael@0:                           EffectKey,
michael@0:                           const char* outputColor,
michael@0:                           const char* inputColor,
michael@0:                           const TransformedCoordsArray&,
michael@0:                           const TextureSamplerArray&) SK_OVERRIDE;
michael@0: 
michael@0:     virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE;
michael@0: 
michael@0: private:
michael@0:     GrGLUniformManager::UniformHandle fKUni;
michael@0: 
michael@0:     typedef GrGLEffect INHERITED;
michael@0: };
michael@0: 
michael@0: ///////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: class GrArithmeticEffect : public GrEffect {
michael@0: public:
michael@0:     static GrEffectRef* Create(float k1, float k2, float k3, float k4, GrTexture* background) {
michael@0:         AutoEffectUnref effect(SkNEW_ARGS(GrArithmeticEffect, (k1, k2, k3, k4, background)));
michael@0:         return CreateEffectRef(effect);
michael@0:     }
michael@0: 
michael@0:     virtual ~GrArithmeticEffect();
michael@0: 
michael@0:     virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE;
michael@0: 
michael@0:     typedef GrGLArithmeticEffect GLEffect;
michael@0:     static const char* Name() { return "Arithmetic"; }
michael@0:     GrTexture* backgroundTexture() const { return fBackgroundAccess.getTexture(); }
michael@0: 
michael@0:     virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE;
michael@0: 
michael@0:     float k1() const { return fK1; }
michael@0:     float k2() const { return fK2; }
michael@0:     float k3() const { return fK3; }
michael@0:     float k4() const { return fK4; }
michael@0: 
michael@0: private:
michael@0:     virtual bool onIsEqual(const GrEffect&) const SK_OVERRIDE;
michael@0: 
michael@0:     GrArithmeticEffect(float k1, float k2, float k3, float k4, GrTexture* background);
michael@0:     float                       fK1, fK2, fK3, fK4;
michael@0:     GrCoordTransform            fBackgroundTransform;
michael@0:     GrTextureAccess             fBackgroundAccess;
michael@0: 
michael@0:     GR_DECLARE_EFFECT_TEST;
michael@0:     typedef GrEffect INHERITED;
michael@0: 
michael@0: };
michael@0: 
michael@0: ///////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: GrArithmeticEffect::GrArithmeticEffect(float k1, float k2, float k3, float k4,
michael@0:                                        GrTexture* background)
michael@0:   : fK1(k1), fK2(k2), fK3(k3), fK4(k4) {
michael@0:     if (background) {
michael@0:         fBackgroundTransform.reset(kLocal_GrCoordSet, background);
michael@0:         this->addCoordTransform(&fBackgroundTransform);
michael@0:         fBackgroundAccess.reset(background);
michael@0:         this->addTextureAccess(&fBackgroundAccess);
michael@0:     } else {
michael@0:         this->setWillReadDstColor();
michael@0:     }
michael@0: }
michael@0: 
michael@0: GrArithmeticEffect::~GrArithmeticEffect() {
michael@0: }
michael@0: 
michael@0: bool GrArithmeticEffect::onIsEqual(const GrEffect& sBase) const {
michael@0:     const GrArithmeticEffect& s = CastEffect<GrArithmeticEffect>(sBase);
michael@0:     return fK1 == s.fK1 &&
michael@0:            fK2 == s.fK2 &&
michael@0:            fK3 == s.fK3 &&
michael@0:            fK4 == s.fK4 &&
michael@0:            backgroundTexture() == s.backgroundTexture();
michael@0: }
michael@0: 
michael@0: const GrBackendEffectFactory& GrArithmeticEffect::getFactory() const {
michael@0:     return GrTBackendEffectFactory<GrArithmeticEffect>::getInstance();
michael@0: }
michael@0: 
michael@0: void GrArithmeticEffect::getConstantColorComponents(GrColor* color, uint32_t* validFlags) const {
michael@0:     // TODO: optimize this
michael@0:     *validFlags = 0;
michael@0: }
michael@0: 
michael@0: ///////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: GrGLArithmeticEffect::GrGLArithmeticEffect(const GrBackendEffectFactory& factory,
michael@0:                                            const GrDrawEffect& drawEffect)
michael@0:    : INHERITED(factory) {
michael@0: }
michael@0: 
michael@0: GrGLArithmeticEffect::~GrGLArithmeticEffect() {
michael@0: }
michael@0: 
michael@0: void GrGLArithmeticEffect::emitCode(GrGLShaderBuilder* builder,
michael@0:                                     const GrDrawEffect& drawEffect,
michael@0:                                     EffectKey key,
michael@0:                                     const char* outputColor,
michael@0:                                     const char* inputColor,
michael@0:                                     const TransformedCoordsArray& coords,
michael@0:                                     const TextureSamplerArray& samplers) {
michael@0: 
michael@0:     GrTexture* backgroundTex = drawEffect.castEffect<GrArithmeticEffect>().backgroundTexture();
michael@0:     const char* dstColor;
michael@0:     if (backgroundTex) {
michael@0:         builder->fsCodeAppend("\t\tvec4 bgColor = ");
michael@0:         builder->fsAppendTextureLookup(samplers[0], coords[0].c_str(), coords[0].type());
michael@0:         builder->fsCodeAppendf(";\n");
michael@0:         dstColor = "bgColor";
michael@0:     } else {
michael@0:         dstColor = builder->dstColor();
michael@0:     }
michael@0: 
michael@0:     SkASSERT(NULL != dstColor);
michael@0:     fKUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
michael@0:                                 kVec4f_GrSLType, "k");
michael@0:     const char* kUni = builder->getUniformCStr(fKUni);
michael@0: 
michael@0:     // We don't try to optimize for this case at all
michael@0:     if (NULL == inputColor) {
michael@0:         builder->fsCodeAppendf("\t\tconst vec4 src = vec4(1);\n");
michael@0:     } else {
michael@0:         builder->fsCodeAppendf("\t\tvec4 src = %s;\n", inputColor);
michael@0:         if (gUseUnpremul) {
michael@0:             builder->fsCodeAppendf("\t\tsrc.rgb = clamp(src.rgb / src.a, 0.0, 1.0);\n");
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     builder->fsCodeAppendf("\t\tvec4 dst = %s;\n", dstColor);
michael@0:     if (gUseUnpremul) {
michael@0:         builder->fsCodeAppendf("\t\tdst.rgb = clamp(dst.rgb / dst.a, 0.0, 1.0);\n");
michael@0:     }
michael@0: 
michael@0:     builder->fsCodeAppendf("\t\t%s = %s.x * src * dst + %s.y * src + %s.z * dst + %s.w;\n", outputColor, kUni, kUni, kUni, kUni);
michael@0:     builder->fsCodeAppendf("\t\t%s = clamp(%s, 0.0, 1.0);\n", outputColor, outputColor);
michael@0:     if (gUseUnpremul) {
michael@0:         builder->fsCodeAppendf("\t\t%s.rgb *= %s.a;\n", outputColor, outputColor);
michael@0:     } else {
michael@0:         builder->fsCodeAppendf("\t\t%s.rgb = min(%s.rgb, %s.a);\n", outputColor, outputColor, outputColor);
michael@0:     }
michael@0: }
michael@0: 
michael@0: void GrGLArithmeticEffect::setData(const GrGLUniformManager& uman, const GrDrawEffect& drawEffect) {
michael@0:     const GrArithmeticEffect& arith = drawEffect.castEffect<GrArithmeticEffect>();
michael@0:     uman.set4f(fKUni, arith.k1(), arith.k2(), arith.k3(), arith.k4());
michael@0: }
michael@0: 
michael@0: GrEffectRef* GrArithmeticEffect::TestCreate(SkRandom* rand,
michael@0:                                             GrContext*,
michael@0:                                             const GrDrawTargetCaps&,
michael@0:                                             GrTexture*[]) {
michael@0:     float k1 = rand->nextF();
michael@0:     float k2 = rand->nextF();
michael@0:     float k3 = rand->nextF();
michael@0:     float k4 = rand->nextF();
michael@0: 
michael@0:     AutoEffectUnref gEffect(SkNEW_ARGS(GrArithmeticEffect, (k1, k2, k3, k4, NULL)));
michael@0:     return CreateEffectRef(gEffect);
michael@0: }
michael@0: 
michael@0: GR_DEFINE_EFFECT_TEST(GrArithmeticEffect);
michael@0: 
michael@0: bool SkArithmeticMode_scalar::asNewEffect(GrEffectRef** effect, GrTexture* background) const {
michael@0:     if (effect) {
michael@0:         *effect = GrArithmeticEffect::Create(SkScalarToFloat(fK[0]),
michael@0:                                              SkScalarToFloat(fK[1]),
michael@0:                                              SkScalarToFloat(fK[2]),
michael@0:                                              SkScalarToFloat(fK[3]),
michael@0:                                              background);
michael@0:     }
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: #endif
michael@0: 
michael@0: SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_START(SkArithmeticMode)
michael@0:     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkArithmeticMode_scalar)
michael@0: SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_END