Home | History | Annotate | Download | only in effects 
      1 /*
      2  * Copyright 2013 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 
      8 #include "SkArithmeticMode.h"
      9 #include "SkColorPriv.h"
     10 #include "SkReadBuffer.h"
     11 #include "SkWriteBuffer.h"
     12 #include "SkString.h"
     13 #include "SkUnPreMultiply.h"
     14 #if SK_SUPPORT_GPU
     15 #include "GrContext.h"
     16 #include "GrCoordTransform.h"
     17 #include "gl/GrGLProcessor.h"
     18 #include "gl/builders/GrGLProgramBuilder.h"
     19 #include "GrTBackendProcessorFactory.h"
     20 #endif
     21 
     22 static const bool gUseUnpremul = false;
     23 
     24 class SkArithmeticMode_scalar : public SkXfermode {
     25 public:
     26     static SkArithmeticMode_scalar* Create(SkScalar k1, SkScalar k2, SkScalar k3, SkScalar k4,
     27                                            bool enforcePMColor) {
     28         return SkNEW_ARGS(SkArithmeticMode_scalar, (k1, k2, k3, k4, enforcePMColor));
     29     }
     30 
     31     virtual void xfer32(SkPMColor dst[], const SkPMColor src[], int count,
     32                         const SkAlpha aa[]) const SK_OVERRIDE;
     33 
     34     SK_TO_STRING_OVERRIDE()
     35     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkArithmeticMode_scalar)
     36 
     37 #if SK_SUPPORT_GPU
     38     virtual bool asFragmentProcessor(GrFragmentProcessor**,
     39                                      GrTexture* background) const SK_OVERRIDE;
     40 #endif
     41 
     42 private:
     43     SkArithmeticMode_scalar(SkScalar k1, SkScalar k2, SkScalar k3, SkScalar k4, bool enforcePMColor) {
     44         fK[0] = k1;
     45         fK[1] = k2;
     46         fK[2] = k3;
     47         fK[3] = k4;
     48         fEnforcePMColor = enforcePMColor;
     49     }
     50 
     51 #ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
     52     SkArithmeticMode_scalar(SkReadBuffer& buffer) : INHERITED(buffer) {
     53         fK[0] = buffer.readScalar();
     54         fK[1] = buffer.readScalar();
     55         fK[2] = buffer.readScalar();
     56         fK[3] = buffer.readScalar();
     57         fEnforcePMColor = buffer.readBool();
     58     }
     59 #endif
     60 
     61     virtual void flatten(SkWriteBuffer& buffer) const SK_OVERRIDE {
     62         buffer.writeScalar(fK[0]);
     63         buffer.writeScalar(fK[1]);
     64         buffer.writeScalar(fK[2]);
     65         buffer.writeScalar(fK[3]);
     66         buffer.writeBool(fEnforcePMColor);
     67     }
     68     SkScalar fK[4];
     69     bool fEnforcePMColor;
     70 
     71     friend class SkArithmeticMode;
     72 
     73     typedef SkXfermode INHERITED;
     74 };
     75 
     76 SkFlattenable* SkArithmeticMode_scalar::CreateProc(SkReadBuffer& buffer) {
     77     const SkScalar k1 = buffer.readScalar();
     78     const SkScalar k2 = buffer.readScalar();
     79     const SkScalar k3 = buffer.readScalar();
     80     const SkScalar k4 = buffer.readScalar();
     81     const bool enforcePMColor = buffer.readBool();
     82     return Create(k1, k2, k3, k4, enforcePMColor);
     83 }
     84 
     85 static int pinToByte(int value) {
     86     if (value < 0) {
     87         value = 0;
     88     } else if (value > 255) {
     89         value = 255;
     90     }
     91     return value;
     92 }
     93 
     94 static int arith(SkScalar k1, SkScalar k2, SkScalar k3, SkScalar k4,
     95                  int src, int dst) {
     96     SkScalar result = SkScalarMul(k1, src * dst) +
     97                       SkScalarMul(k2, src) +
     98                       SkScalarMul(k3, dst) +
     99                       k4;
    100     int res = SkScalarRoundToInt(result);
    101     return pinToByte(res);
    102 }
    103 
    104 static int blend(int src, int dst, int scale) {
    105     return dst + ((src - dst) * scale >> 8);
    106 }
    107 
    108 static bool needsUnpremul(int alpha) {
    109     return 0 != alpha && 0xFF != alpha;
    110 }
    111 
    112 void SkArithmeticMode_scalar::xfer32(SkPMColor dst[], const SkPMColor src[],
    113                                  int count, const SkAlpha aaCoverage[]) const {
    114     SkScalar k1 = fK[0] / 255;
    115     SkScalar k2 = fK[1];
    116     SkScalar k3 = fK[2];
    117     SkScalar k4 = fK[3] * 255;
    118 
    119     for (int i = 0; i < count; ++i) {
    120         if ((NULL == aaCoverage) || aaCoverage[i]) {
    121             SkPMColor sc = src[i];
    122             SkPMColor dc = dst[i];
    123 
    124             int a, r, g, b;
    125 
    126             if (gUseUnpremul) {
    127                 int sa = SkGetPackedA32(sc);
    128                 int da = SkGetPackedA32(dc);
    129 
    130                 int srcNeedsUnpremul = needsUnpremul(sa);
    131                 int dstNeedsUnpremul = needsUnpremul(da);
    132 
    133                 if (!srcNeedsUnpremul && !dstNeedsUnpremul) {
    134                     a = arith(k1, k2, k3, k4, sa, da);
    135                     r = arith(k1, k2, k3, k4, SkGetPackedR32(sc), SkGetPackedR32(dc));
    136                     g = arith(k1, k2, k3, k4, SkGetPackedG32(sc), SkGetPackedG32(dc));
    137                     b = arith(k1, k2, k3, k4, SkGetPackedB32(sc), SkGetPackedB32(dc));
    138                 } else {
    139                     int sr = SkGetPackedR32(sc);
    140                     int sg = SkGetPackedG32(sc);
    141                     int sb = SkGetPackedB32(sc);
    142                     if (srcNeedsUnpremul) {
    143                         SkUnPreMultiply::Scale scale = SkUnPreMultiply::GetScale(sa);
    144                         sr = SkUnPreMultiply::ApplyScale(scale, sr);
    145                         sg = SkUnPreMultiply::ApplyScale(scale, sg);
    146                         sb = SkUnPreMultiply::ApplyScale(scale, sb);
    147                     }
    148 
    149                     int dr = SkGetPackedR32(dc);
    150                     int dg = SkGetPackedG32(dc);
    151                     int db = SkGetPackedB32(dc);
    152                     if (dstNeedsUnpremul) {
    153                         SkUnPreMultiply::Scale scale = SkUnPreMultiply::GetScale(da);
    154                         dr = SkUnPreMultiply::ApplyScale(scale, dr);
    155                         dg = SkUnPreMultiply::ApplyScale(scale, dg);
    156                         db = SkUnPreMultiply::ApplyScale(scale, db);
    157                     }
    158 
    159                     a = arith(k1, k2, k3, k4, sa, da);
    160                     r = arith(k1, k2, k3, k4, sr, dr);
    161                     g = arith(k1, k2, k3, k4, sg, dg);
    162                     b = arith(k1, k2, k3, k4, sb, db);
    163                 }
    164             } else {
    165                 a = arith(k1, k2, k3, k4, SkGetPackedA32(sc), SkGetPackedA32(dc));
    166                 r = arith(k1, k2, k3, k4, SkGetPackedR32(sc), SkGetPackedR32(dc));
    167                 g = arith(k1, k2, k3, k4, SkGetPackedG32(sc), SkGetPackedG32(dc));
    168                 b = arith(k1, k2, k3, k4, SkGetPackedB32(sc), SkGetPackedB32(dc));
    169                 if (fEnforcePMColor) {
    170                     r = SkMin32(r, a);
    171                     g = SkMin32(g, a);
    172                     b = SkMin32(b, a);
    173                 }
    174             }
    175 
    176             // apply antialias coverage if necessary
    177             if (aaCoverage && 0xFF != aaCoverage[i]) {
    178                 int scale = aaCoverage[i] + (aaCoverage[i] >> 7);
    179                 a = blend(a, SkGetPackedA32(sc), scale);
    180                 r = blend(r, SkGetPackedR32(sc), scale);
    181                 g = blend(g, SkGetPackedG32(sc), scale);
    182                 b = blend(b, SkGetPackedB32(sc), scale);
    183             }
    184 
    185             // turn the result back into premul
    186             if (gUseUnpremul && (0xFF != a)) {
    187                 int scale = a + (a >> 7);
    188                 r = SkAlphaMul(r, scale);
    189                 g = SkAlphaMul(g, scale);
    190                 b = SkAlphaMul(b, scale);
    191             }
    192             dst[i] = fEnforcePMColor ? SkPackARGB32(a, r, g, b) : SkPackARGB32NoCheck(a, r, g, b);
    193         }
    194     }
    195 }
    196 
    197 #ifndef SK_IGNORE_TO_STRING
    198 void SkArithmeticMode_scalar::toString(SkString* str) const {
    199     str->append("SkArithmeticMode_scalar: ");
    200     for (int i = 0; i < 4; ++i) {
    201         str->appendScalar(fK[i]);
    202         str->append(" ");
    203     }
    204     str->appendS32(fEnforcePMColor ? 1 : 0);
    205 }
    206 #endif
    207 
    208 ///////////////////////////////////////////////////////////////////////////////
    209 
    210 static bool fitsInBits(SkScalar x, int bits) {
    211     return SkScalarAbs(x) < (1 << (bits - 1));
    212 }
    213 
    214 #if 0 // UNUSED
    215 static int32_t toDot8(SkScalar x) {
    216     return (int32_t)(x * 256);
    217 }
    218 #endif
    219 
    220 SkXfermode* SkArithmeticMode::Create(SkScalar k1, SkScalar k2,
    221                                      SkScalar k3, SkScalar k4,
    222                                      bool enforcePMColor) {
    223     if (fitsInBits(k1, 8) && fitsInBits(k2, 16) &&
    224         fitsInBits(k2, 16) && fitsInBits(k2, 24)) {
    225 
    226 #if 0 // UNUSED
    227         int32_t i1 = toDot8(k1);
    228         int32_t i2 = toDot8(k2);
    229         int32_t i3 = toDot8(k3);
    230         int32_t i4 = toDot8(k4);
    231         if (i1) {
    232             return SkNEW_ARGS(SkArithmeticMode_quad, (i1, i2, i3, i4));
    233         }
    234         if (0 == i2) {
    235             return SkNEW_ARGS(SkArithmeticMode_dst, (i3, i4));
    236         }
    237         if (0 == i3) {
    238             return SkNEW_ARGS(SkArithmeticMode_src, (i2, i4));
    239         }
    240         return SkNEW_ARGS(SkArithmeticMode_linear, (i2, i3, i4));
    241 #endif
    242     }
    243     return SkArithmeticMode_scalar::Create(k1, k2, k3, k4, enforcePMColor);
    244 }
    245 
    246 
    247 //////////////////////////////////////////////////////////////////////////////
    248 
    249 #if SK_SUPPORT_GPU
    250 
    251 class GrGLArithmeticEffect : public GrGLFragmentProcessor {
    252 public:
    253     GrGLArithmeticEffect(const GrBackendProcessorFactory&, const GrProcessor&);
    254     virtual ~GrGLArithmeticEffect();
    255 
    256     virtual void emitCode(GrGLProgramBuilder*,
    257                           const GrFragmentProcessor&,
    258                           const GrProcessorKey&,
    259                           const char* outputColor,
    260                           const char* inputColor,
    261                           const TransformedCoordsArray&,
    262                           const TextureSamplerArray&) SK_OVERRIDE;
    263 
    264     virtual void setData(const GrGLProgramDataManager&, const GrProcessor&) SK_OVERRIDE;
    265 
    266     static void GenKey(const GrProcessor&, const GrGLCaps& caps, GrProcessorKeyBuilder* b);
    267 
    268 private:
    269     GrGLProgramDataManager::UniformHandle fKUni;
    270     bool fEnforcePMColor;
    271 
    272     typedef GrGLFragmentProcessor INHERITED;
    273 };
    274 
    275 ///////////////////////////////////////////////////////////////////////////////
    276 
    277 class GrArithmeticEffect : public GrFragmentProcessor {
    278 public:
    279     static GrFragmentProcessor* Create(float k1, float k2, float k3, float k4, bool enforcePMColor,
    280                                GrTexture* background) {
    281         return SkNEW_ARGS(GrArithmeticEffect, (k1, k2, k3, k4, enforcePMColor, background));
    282     }
    283 
    284     virtual ~GrArithmeticEffect();
    285 
    286     virtual const GrBackendFragmentProcessorFactory& getFactory() const SK_OVERRIDE;
    287 
    288     typedef GrGLArithmeticEffect GLProcessor;
    289     static const char* Name() { return "Arithmetic"; }
    290     GrTexture* backgroundTexture() const { return fBackgroundAccess.getTexture(); }
    291 
    292     virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE;
    293 
    294     float k1() const { return fK1; }
    295     float k2() const { return fK2; }
    296     float k3() const { return fK3; }
    297     float k4() const { return fK4; }
    298     bool enforcePMColor() const { return fEnforcePMColor; }
    299 
    300 private:
    301     virtual bool onIsEqual(const GrProcessor&) const SK_OVERRIDE;
    302 
    303     GrArithmeticEffect(float k1, float k2, float k3, float k4, bool enforcePMColor,
    304                        GrTexture* background);
    305     float                       fK1, fK2, fK3, fK4;
    306     bool                        fEnforcePMColor;
    307     GrCoordTransform            fBackgroundTransform;
    308     GrTextureAccess             fBackgroundAccess;
    309 
    310     GR_DECLARE_FRAGMENT_PROCESSOR_TEST;
    311     typedef GrFragmentProcessor INHERITED;
    312 
    313 };
    314 
    315 ///////////////////////////////////////////////////////////////////////////////
    316 
    317 GrArithmeticEffect::GrArithmeticEffect(float k1, float k2, float k3, float k4,
    318                                        bool enforcePMColor, GrTexture* background)
    319   : fK1(k1), fK2(k2), fK3(k3), fK4(k4), fEnforcePMColor(enforcePMColor) {
    320     if (background) {
    321         fBackgroundTransform.reset(kLocal_GrCoordSet, background);
    322         this->addCoordTransform(&fBackgroundTransform);
    323         fBackgroundAccess.reset(background);
    324         this->addTextureAccess(&fBackgroundAccess);
    325     } else {
    326         this->setWillReadDstColor();
    327     }
    328 }
    329 
    330 GrArithmeticEffect::~GrArithmeticEffect() {
    331 }
    332 
    333 bool GrArithmeticEffect::onIsEqual(const GrProcessor& sBase) const {
    334     const GrArithmeticEffect& s = sBase.cast<GrArithmeticEffect>();
    335     return fK1 == s.fK1 &&
    336            fK2 == s.fK2 &&
    337            fK3 == s.fK3 &&
    338            fK4 == s.fK4 &&
    339            fEnforcePMColor == s.fEnforcePMColor &&
    340            backgroundTexture() == s.backgroundTexture();
    341 }
    342 
    343 const GrBackendFragmentProcessorFactory& GrArithmeticEffect::getFactory() const {
    344     return GrTBackendFragmentProcessorFactory<GrArithmeticEffect>::getInstance();
    345 }
    346 
    347 void GrArithmeticEffect::getConstantColorComponents(GrColor* color, uint32_t* validFlags) const {
    348     // TODO: optimize this
    349     *validFlags = 0;
    350 }
    351 
    352 ///////////////////////////////////////////////////////////////////////////////
    353 
    354 GrGLArithmeticEffect::GrGLArithmeticEffect(const GrBackendProcessorFactory& factory,
    355                                            const GrProcessor&)
    356    : INHERITED(factory),
    357      fEnforcePMColor(true) {
    358 }
    359 
    360 GrGLArithmeticEffect::~GrGLArithmeticEffect() {
    361 }
    362 
    363 void GrGLArithmeticEffect::emitCode(GrGLProgramBuilder* builder,
    364                                     const GrFragmentProcessor& fp,
    365                                     const GrProcessorKey& key,
    366                                     const char* outputColor,
    367                                     const char* inputColor,
    368                                     const TransformedCoordsArray& coords,
    369                                     const TextureSamplerArray& samplers) {
    370 
    371     GrTexture* backgroundTex = fp.cast<GrArithmeticEffect>().backgroundTexture();
    372     GrGLFragmentShaderBuilder* fsBuilder = builder->getFragmentShaderBuilder();
    373     const char* dstColor;
    374     if (backgroundTex) {
    375         fsBuilder->codeAppend("\t\tvec4 bgColor = ");
    376         fsBuilder->appendTextureLookup(samplers[0], coords[0].c_str(), coords[0].getType());
    377         fsBuilder->codeAppendf(";\n");
    378         dstColor = "bgColor";
    379     } else {
    380         dstColor = fsBuilder->dstColor();
    381     }
    382 
    383     SkASSERT(dstColor);
    384     fKUni = builder->addUniform(GrGLProgramBuilder::kFragment_Visibility,
    385                                 kVec4f_GrSLType, "k");
    386     const char* kUni = builder->getUniformCStr(fKUni);
    387 
    388     // We don't try to optimize for this case at all
    389     if (NULL == inputColor) {
    390         fsBuilder->codeAppendf("\t\tconst vec4 src = vec4(1);\n");
    391     } else {
    392         fsBuilder->codeAppendf("\t\tvec4 src = %s;\n", inputColor);
    393         if (gUseUnpremul) {
    394             fsBuilder->codeAppendf("\t\tsrc.rgb = clamp(src.rgb / src.a, 0.0, 1.0);\n");
    395         }
    396     }
    397 
    398     fsBuilder->codeAppendf("\t\tvec4 dst = %s;\n", dstColor);
    399     if (gUseUnpremul) {
    400         fsBuilder->codeAppendf("\t\tdst.rgb = clamp(dst.rgb / dst.a, 0.0, 1.0);\n");
    401     }
    402 
    403     fsBuilder->codeAppendf("\t\t%s = %s.x * src * dst + %s.y * src + %s.z * dst + %s.w;\n", outputColor, kUni, kUni, kUni, kUni);
    404     fsBuilder->codeAppendf("\t\t%s = clamp(%s, 0.0, 1.0);\n", outputColor, outputColor);
    405     if (gUseUnpremul) {
    406         fsBuilder->codeAppendf("\t\t%s.rgb *= %s.a;\n", outputColor, outputColor);
    407     } else if (fEnforcePMColor) {
    408         fsBuilder->codeAppendf("\t\t%s.rgb = min(%s.rgb, %s.a);\n", outputColor, outputColor, outputColor);
    409     }
    410 }
    411 
    412 void GrGLArithmeticEffect::setData(const GrGLProgramDataManager& pdman,
    413                                    const GrProcessor& processor) {
    414     const GrArithmeticEffect& arith = processor.cast<GrArithmeticEffect>();
    415     pdman.set4f(fKUni, arith.k1(), arith.k2(), arith.k3(), arith.k4());
    416     fEnforcePMColor = arith.enforcePMColor();
    417 }
    418 
    419 void GrGLArithmeticEffect::GenKey(const GrProcessor& processor,
    420                                   const GrGLCaps&, GrProcessorKeyBuilder* b) {
    421     const GrArithmeticEffect& arith = processor.cast<GrArithmeticEffect>();
    422     uint32_t key = arith.enforcePMColor() ? 1 : 0;
    423     if (arith.backgroundTexture()) {
    424         key |= 2;
    425     }
    426     b->add32(key);
    427 }
    428 
    429 GrFragmentProcessor* GrArithmeticEffect::TestCreate(SkRandom* rand,
    430                                                     GrContext*,
    431                                                     const GrDrawTargetCaps&,
    432                                                     GrTexture*[]) {
    433     float k1 = rand->nextF();
    434     float k2 = rand->nextF();
    435     float k3 = rand->nextF();
    436     float k4 = rand->nextF();
    437     bool enforcePMColor = rand->nextBool();
    438 
    439     return SkNEW_ARGS(GrArithmeticEffect, (k1, k2, k3, k4, enforcePMColor, NULL));
    440 }
    441 
    442 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrArithmeticEffect);
    443 
    444 bool SkArithmeticMode_scalar::asFragmentProcessor(GrFragmentProcessor** fp,
    445                                                   GrTexture* background) const {
    446     if (fp) {
    447         *fp = GrArithmeticEffect::Create(SkScalarToFloat(fK[0]),
    448                                          SkScalarToFloat(fK[1]),
    449                                          SkScalarToFloat(fK[2]),
    450                                          SkScalarToFloat(fK[3]),
    451                                          fEnforcePMColor,
    452                                          background);
    453     }
    454     return true;
    455 }
    456 
    457 #endif
    458 
    459 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_START(SkArithmeticMode)
    460     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkArithmeticMode_scalar)
    461 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_END
    462