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