src/third_party/skia/src/effects/SkArithmeticMode.cpp

   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(GrGLFPBuilder*,
 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     float k1() const { return fK1; }
 293     float k2() const { return fK2; }
 294     float k3() const { return fK3; }
 295     float k4() const { return fK4; }
 296     bool enforcePMColor() const { return fEnforcePMColor; }
 297
 298 private:
 299     virtual bool onIsEqual(const GrFragmentProcessor&) const SK_OVERRIDE;
 300
 301     virtual void onComputeInvariantOutput(InvariantOutput* inout) 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 GrFragmentProcessor& 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 }
 341
 342 const GrBackendFragmentProcessorFactory& GrArithmeticEffect::getFactory() const {
 343     return GrTBackendFragmentProcessorFactory<GrArithmeticEffect>::getInstance();
 344 }
 345
 346 void GrArithmeticEffect::onComputeInvariantOutput(InvariantOutput* inout) const {
 347     // TODO: optimize this
 348     inout->setToUnknown(InvariantOutput::kWill_ReadInput);
 349 }
 350
 351 ///////////////////////////////////////////////////////////////////////////////
 352
 353 GrGLArithmeticEffect::GrGLArithmeticEffect(const GrBackendProcessorFactory& factory,
 354                                            const GrProcessor&)
 355    : INHERITED(factory),
 356      fEnforcePMColor(true) {
 357 }
 358
 359 GrGLArithmeticEffect::~GrGLArithmeticEffect() {
 360 }
 361
 362 void GrGLArithmeticEffect::emitCode(GrGLFPBuilder* builder,
 363                                     const GrFragmentProcessor& fp,
 364                                     const GrProcessorKey& key,
 365                                     const char* outputColor,
 366                                     const char* inputColor,
 367                                     const TransformedCoordsArray& coords,
 368                                     const TextureSamplerArray& samplers) {
 369
 370     GrTexture* backgroundTex = fp.cast<GrArithmeticEffect>().backgroundTexture();
 371     GrGLFPFragmentBuilder* fsBuilder = builder->getFragmentShaderBuilder();
 372     const char* dstColor;
 373     if (backgroundTex) {
 374         fsBuilder->codeAppend("\t\tvec4 bgColor = ");
 375         fsBuilder->appendTextureLookup(samplers[0], coords[0].c_str(), coords[0].getType());
 376         fsBuilder->codeAppendf(";\n");
 377         dstColor = "bgColor";
 378     } else {
 379         dstColor = fsBuilder->dstColor();
 380     }
 381
 382     SkASSERT(dstColor);
 383     fKUni = builder->addUniform(GrGLProgramBuilder::kFragment_Visibility,
 384                                 kVec4f_GrSLType, "k");
 385     const char* kUni = builder->getUniformCStr(fKUni);
 386
 387     // We don't try to optimize for this case at all
 388     if (NULL == inputColor) {
 389         fsBuilder->codeAppendf("\t\tconst vec4 src = vec4(1);\n");
 390     } else {
 391         fsBuilder->codeAppendf("\t\tvec4 src = %s;\n", inputColor);
 392         if (gUseUnpremul) {
 393             fsBuilder->codeAppendf("\t\tsrc.rgb = clamp(src.rgb / src.a, 0.0, 1.0);\n");
 394         }
 395     }
 396
 397     fsBuilder->codeAppendf("\t\tvec4 dst = %s;\n", dstColor);
 398     if (gUseUnpremul) {
 399         fsBuilder->codeAppendf("\t\tdst.rgb = clamp(dst.rgb / dst.a, 0.0, 1.0);\n");
 400     }
 401
 402     fsBuilder->codeAppendf("\t\t%s = %s.x * src * dst + %s.y * src + %s.z * dst + %s.w;\n", outputColor, kUni, kUni, kUni, kUni);
 403     fsBuilder->codeAppendf("\t\t%s = clamp(%s, 0.0, 1.0);\n", outputColor, outputColor);
 404     if (gUseUnpremul) {
 405         fsBuilder->codeAppendf("\t\t%s.rgb *= %s.a;\n", outputColor, outputColor);
 406     } else if (fEnforcePMColor) {
 407         fsBuilder->codeAppendf("\t\t%s.rgb = min(%s.rgb, %s.a);\n", outputColor, outputColor, outputColor);
 408     }
 409 }
 410
 411 void GrGLArithmeticEffect::setData(const GrGLProgramDataManager& pdman,
 412                                    const GrProcessor& processor) {
 413     const GrArithmeticEffect& arith = processor.cast<GrArithmeticEffect>();
 414     pdman.set4f(fKUni, arith.k1(), arith.k2(), arith.k3(), arith.k4());
 415     fEnforcePMColor = arith.enforcePMColor();
 416 }
 417
 418 void GrGLArithmeticEffect::GenKey(const GrProcessor& processor,
 419                                   const GrGLCaps&, GrProcessorKeyBuilder* b) {
 420     const GrArithmeticEffect& arith = processor.cast<GrArithmeticEffect>();
 421     uint32_t key = arith.enforcePMColor() ? 1 : 0;
 422     if (arith.backgroundTexture()) {
 423         key |= 2;
 424     }
 425     b->add32(key);
 426 }
 427
 428 GrFragmentProcessor* GrArithmeticEffect::TestCreate(SkRandom* rand,
 429                                                     GrContext*,
 430                                                     const GrDrawTargetCaps&,
 431                                                     GrTexture*[]) {
 432     float k1 = rand->nextF();
 433     float k2 = rand->nextF();
 434     float k3 = rand->nextF();
 435     float k4 = rand->nextF();
 436     bool enforcePMColor = rand->nextBool();
 437
 438     return SkNEW_ARGS(GrArithmeticEffect, (k1, k2, k3, k4, enforcePMColor, NULL));
 439 }
 440
 441 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrArithmeticEffect);
 442
 443 bool SkArithmeticMode_scalar::asFragmentProcessor(GrFragmentProcessor** fp,
 444                                                   GrTexture* background) const {
 445     if (fp) {
 446         *fp = GrArithmeticEffect::Create(SkScalarToFloat(fK[0]),
 447                                          SkScalarToFloat(fK[1]),
 448                                          SkScalarToFloat(fK[2]),
 449                                          SkScalarToFloat(fK[3]),
 450                                          fEnforcePMColor,
 451                                          background);
 452     }
 453     return true;
 454 }
 455
 456 #endif
 457
 458 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_START(SkArithmeticMode)
 459     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkArithmeticMode_scalar)
 460 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_END