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