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