src/third_party/skia/src/effects/SkDisplacementMapEffect.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 "SkDisplacementMapEffect.h"
   9 #include "SkReadBuffer.h"
  10 #include "SkWriteBuffer.h"
  11 #include "SkUnPreMultiply.h"
  12 #include "SkColorPriv.h"
  13 #if SK_SUPPORT_GPU
  14 #include "GrContext.h"
  15 #include "GrCoordTransform.h"
  16 #include "gl/GrGLProcessor.h"
  17 #include "gl/builders/GrGLProgramBuilder.h"
  18 #include "GrTBackendProcessorFactory.h"
  19 #endif
  20
  21 namespace {
  22
  23 #define kChannelSelectorKeyBits 3; // Max value is 4, so 3 bits are required at most
  24
  25 template<SkDisplacementMapEffect::ChannelSelectorType type>
  26 uint32_t getValue(SkColor, const SkUnPreMultiply::Scale*) {
  27     SkDEBUGFAIL("Unknown channel selector");
  28     return 0;
  29 }
  30
  31 template<> uint32_t getValue<SkDisplacementMapEffect::kR_ChannelSelectorType>(
  32     SkColor l, const SkUnPreMultiply::Scale* table) {
  33     return SkUnPreMultiply::ApplyScale(table[SkGetPackedA32(l)], SkGetPackedR32(l));
  34 }
  35
  36 template<> uint32_t getValue<SkDisplacementMapEffect::kG_ChannelSelectorType>(
  37     SkColor l, const SkUnPreMultiply::Scale* table) {
  38     return SkUnPreMultiply::ApplyScale(table[SkGetPackedA32(l)], SkGetPackedG32(l));
  39 }
  40
  41 template<> uint32_t getValue<SkDisplacementMapEffect::kB_ChannelSelectorType>(
  42     SkColor l, const SkUnPreMultiply::Scale* table) {
  43     return SkUnPreMultiply::ApplyScale(table[SkGetPackedA32(l)], SkGetPackedB32(l));
  44 }
  45
  46 template<> uint32_t getValue<SkDisplacementMapEffect::kA_ChannelSelectorType>(
  47     SkColor l, const SkUnPreMultiply::Scale*) {
  48     return SkGetPackedA32(l);
  49 }
  50
  51 template<SkDisplacementMapEffect::ChannelSelectorType typeX,
  52          SkDisplacementMapEffect::ChannelSelectorType typeY>
  53 void computeDisplacement(const SkVector& scale, SkBitmap* dst,
  54                          SkBitmap* displ, const SkIPoint& offset,
  55                          SkBitmap* src,
  56                          const SkIRect& bounds)
  57 {
  58     static const SkScalar Inv8bit = SkScalarDiv(SK_Scalar1, 255.0f);
  59     const int srcW = src->width();
  60     const int srcH = src->height();
  61     const SkVector scaleForColor = SkVector::Make(SkScalarMul(scale.fX, Inv8bit),
  62                                                   SkScalarMul(scale.fY, Inv8bit));
  63     const SkVector scaleAdj = SkVector::Make(SK_ScalarHalf - SkScalarMul(scale.fX, SK_ScalarHalf),
  64                                              SK_ScalarHalf - SkScalarMul(scale.fY, SK_ScalarHalf));
  65     const SkUnPreMultiply::Scale* table = SkUnPreMultiply::GetScaleTable();
  66     SkPMColor* dstPtr = dst->getAddr32(0, 0);
  67     for (int y = bounds.top(); y < bounds.bottom(); ++y) {
  68         const SkPMColor* displPtr = displ->getAddr32(bounds.left() + offset.fX,
  69                                                      y + offset.fY);
  70         for (int x = bounds.left(); x < bounds.right(); ++x, ++displPtr) {
  71             const SkScalar displX = SkScalarMul(scaleForColor.fX,
  72                 SkIntToScalar(getValue<typeX>(*displPtr, table))) + scaleAdj.fX;
  73             const SkScalar displY = SkScalarMul(scaleForColor.fY,
  74                 SkIntToScalar(getValue<typeY>(*displPtr, table))) + scaleAdj.fY;
  75             // Truncate the displacement values
  76             const int srcX = x + SkScalarTruncToInt(displX);
  77             const int srcY = y + SkScalarTruncToInt(displY);
  78             *dstPtr++ = ((srcX < 0) || (srcX >= srcW) || (srcY < 0) || (srcY >= srcH)) ?
  79                       0 : *(src->getAddr32(srcX, srcY));
  80         }
  81     }
  82 }
  83
  84 template<SkDisplacementMapEffect::ChannelSelectorType typeX>
  85 void computeDisplacement(SkDisplacementMapEffect::ChannelSelectorType yChannelSelector,
  86                          const SkVector& scale, SkBitmap* dst,
  87                          SkBitmap* displ, const SkIPoint& offset,
  88                          SkBitmap* src,
  89                          const SkIRect& bounds)
  90 {
  91     switch (yChannelSelector) {
  92       case SkDisplacementMapEffect::kR_ChannelSelectorType:
  93         computeDisplacement<typeX, SkDisplacementMapEffect::kR_ChannelSelectorType>(
  94             scale, dst, displ, offset, src, bounds);
  95         break;
  96       case SkDisplacementMapEffect::kG_ChannelSelectorType:
  97         computeDisplacement<typeX, SkDisplacementMapEffect::kG_ChannelSelectorType>(
  98             scale, dst, displ, offset, src, bounds);
  99         break;
 100       case SkDisplacementMapEffect::kB_ChannelSelectorType:
 101         computeDisplacement<typeX, SkDisplacementMapEffect::kB_ChannelSelectorType>(
 102             scale, dst, displ, offset, src, bounds);
 103         break;
 104       case SkDisplacementMapEffect::kA_ChannelSelectorType:
 105         computeDisplacement<typeX, SkDisplacementMapEffect::kA_ChannelSelectorType>(
 106             scale, dst, displ, offset, src, bounds);
 107         break;
 108       case SkDisplacementMapEffect::kUnknown_ChannelSelectorType:
 109       default:
 110         SkDEBUGFAIL("Unknown Y channel selector");
 111     }
 112 }
 113
 114 void computeDisplacement(SkDisplacementMapEffect::ChannelSelectorType xChannelSelector,
 115                          SkDisplacementMapEffect::ChannelSelectorType yChannelSelector,
 116                          const SkVector& scale, SkBitmap* dst,
 117                          SkBitmap* displ, const SkIPoint& offset,
 118                          SkBitmap* src,
 119                          const SkIRect& bounds)
 120 {
 121     switch (xChannelSelector) {
 122       case SkDisplacementMapEffect::kR_ChannelSelectorType:
 123         computeDisplacement<SkDisplacementMapEffect::kR_ChannelSelectorType>(
 124             yChannelSelector, scale, dst, displ, offset, src, bounds);
 125         break;
 126       case SkDisplacementMapEffect::kG_ChannelSelectorType:
 127         computeDisplacement<SkDisplacementMapEffect::kG_ChannelSelectorType>(
 128             yChannelSelector, scale, dst, displ, offset, src, bounds);
 129         break;
 130       case SkDisplacementMapEffect::kB_ChannelSelectorType:
 131         computeDisplacement<SkDisplacementMapEffect::kB_ChannelSelectorType>(
 132             yChannelSelector, scale, dst, displ, offset, src, bounds);
 133         break;
 134       case SkDisplacementMapEffect::kA_ChannelSelectorType:
 135         computeDisplacement<SkDisplacementMapEffect::kA_ChannelSelectorType>(
 136             yChannelSelector, scale, dst, displ, offset, src, bounds);
 137         break;
 138       case SkDisplacementMapEffect::kUnknown_ChannelSelectorType:
 139       default:
 140         SkDEBUGFAIL("Unknown X channel selector");
 141     }
 142 }
 143
 144 bool channel_selector_type_is_valid(SkDisplacementMapEffect::ChannelSelectorType cst) {
 145     switch (cst) {
 146     case SkDisplacementMapEffect::kUnknown_ChannelSelectorType:
 147     case SkDisplacementMapEffect::kR_ChannelSelectorType:
 148     case SkDisplacementMapEffect::kG_ChannelSelectorType:
 149     case SkDisplacementMapEffect::kB_ChannelSelectorType:
 150     case SkDisplacementMapEffect::kA_ChannelSelectorType:
 151         return true;
 152     default:
 153         break;
 154     }
 155     return false;
 156 }
 157
 158 } // end namespace
 159
 160 ///////////////////////////////////////////////////////////////////////////////
 161
 162 SkDisplacementMapEffect* SkDisplacementMapEffect::Create(ChannelSelectorType xChannelSelector,
 163                                                          ChannelSelectorType yChannelSelector,
 164                                                          SkScalar scale,
 165                                                          SkImageFilter* displacement,
 166                                                          SkImageFilter* color,
 167                                                          const CropRect* cropRect, uint32_t uniqueID) {
 168     if (!channel_selector_type_is_valid(xChannelSelector) ||
 169         !channel_selector_type_is_valid(yChannelSelector)) {
 170         return NULL;
 171     }
 172
 173     SkImageFilter* inputs[2] = { displacement, color };
 174     return SkNEW_ARGS(SkDisplacementMapEffect, (xChannelSelector, yChannelSelector, scale,
 175                                                 inputs, cropRect, uniqueID));
 176 }
 177
 178 SkDisplacementMapEffect::SkDisplacementMapEffect(ChannelSelectorType xChannelSelector,
 179                                                  ChannelSelectorType yChannelSelector,
 180                                                  SkScalar scale,
 181                                                  SkImageFilter* inputs[2],
 182                                                  const CropRect* cropRect,
 183                                                  uint32_t uniqueID)
 184   : INHERITED(2, inputs, cropRect, uniqueID)
 185   , fXChannelSelector(xChannelSelector)
 186   , fYChannelSelector(yChannelSelector)
 187   , fScale(scale)
 188 {
 189 }
 190
 191 SkDisplacementMapEffect::~SkDisplacementMapEffect() {
 192 }
 193
 194 #ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
 195 SkDisplacementMapEffect::SkDisplacementMapEffect(SkReadBuffer& buffer)
 196   : INHERITED(2, buffer)
 197 {
 198     fXChannelSelector = (SkDisplacementMapEffect::ChannelSelectorType) buffer.readInt();
 199     fYChannelSelector = (SkDisplacementMapEffect::ChannelSelectorType) buffer.readInt();
 200     fScale            = buffer.readScalar();
 201     buffer.validate(channel_selector_type_is_valid(fXChannelSelector) &&
 202                     channel_selector_type_is_valid(fYChannelSelector) &&
 203                     SkScalarIsFinite(fScale));
 204 }
 205 #endif
 206
 207 SkFlattenable* SkDisplacementMapEffect::CreateProc(SkReadBuffer& buffer) {
 208     SK_IMAGEFILTER_UNFLATTEN_COMMON(common, 2);
 209     ChannelSelectorType xsel = (ChannelSelectorType)buffer.readInt();
 210     ChannelSelectorType ysel = (ChannelSelectorType)buffer.readInt();
 211     SkScalar scale = buffer.readScalar();
 212     return Create(xsel, ysel, scale, common.getInput(0), common.getInput(1), &common.cropRect(), common.uniqueID());
 213 }
 214
 215 void SkDisplacementMapEffect::flatten(SkWriteBuffer& buffer) const {
 216     this->INHERITED::flatten(buffer);
 217     buffer.writeInt((int) fXChannelSelector);
 218     buffer.writeInt((int) fYChannelSelector);
 219     buffer.writeScalar(fScale);
 220 }
 221
 222 bool SkDisplacementMapEffect::onFilterImage(Proxy* proxy,
 223                                             const SkBitmap& src,
 224                                             const Context& ctx,
 225                                             SkBitmap* dst,
 226                                             SkIPoint* offset) const {
 227     SkBitmap displ = src, color = src;
 228     const SkImageFilter* colorInput = getColorInput();
 229     const SkImageFilter* displInput = getDisplacementInput();
 230     SkIPoint colorOffset = SkIPoint::Make(0, 0), displOffset = SkIPoint::Make(0, 0);
 231     if ((colorInput && !colorInput->filterImage(proxy, src, ctx, &color, &colorOffset)) ||
 232         (displInput && !displInput->filterImage(proxy, src, ctx, &displ, &displOffset))) {
 233         return false;
 234     }
 235     if ((displ.colorType() != kN32_SkColorType) ||
 236         (color.colorType() != kN32_SkColorType)) {
 237         return false;
 238     }
 239     SkIRect bounds;
 240     // Since computeDisplacement does bounds checking on color pixel access, we don't need to pad
 241     // the color bitmap to bounds here.
 242     if (!this->applyCropRect(ctx, color, colorOffset, &bounds)) {
 243         return false;
 244     }
 245     SkIRect displBounds;
 246     if (!this->applyCropRect(ctx, proxy, displ, &displOffset, &displBounds, &displ)) {
 247         return false;
 248     }
 249     if (!bounds.intersect(displBounds)) {
 250         return false;
 251     }
 252     SkAutoLockPixels alp_displacement(displ), alp_color(color);
 253     if (!displ.getPixels() || !color.getPixels()) {
 254         return false;
 255     }
 256
 257     if (!dst->tryAllocPixels(color.info().makeWH(bounds.width(), bounds.height()))) {
 258         return false;
 259     }
 260
 261     SkVector scale = SkVector::Make(fScale, fScale);
 262     ctx.ctm().mapVectors(&scale, 1);
 263     SkIRect colorBounds = bounds;
 264     colorBounds.offset(-colorOffset);
 265
 266     computeDisplacement(fXChannelSelector, fYChannelSelector, scale, dst,
 267                         &displ, colorOffset - displOffset, &color, colorBounds);
 268
 269     offset->fX = bounds.left();
 270     offset->fY = bounds.top();
 271     return true;
 272 }
 273
 274 void SkDisplacementMapEffect::computeFastBounds(const SkRect& src, SkRect* dst) const {
 275     if (getColorInput()) {
 276         getColorInput()->computeFastBounds(src, dst);
 277     } else {
 278         *dst = src;
 279     }
 280     dst->outset(fScale * SK_ScalarHalf, fScale * SK_ScalarHalf);
 281 }
 282
 283 bool SkDisplacementMapEffect::onFilterBounds(const SkIRect& src, const SkMatrix& ctm,
 284                                    SkIRect* dst) const {
 285     SkIRect bounds = src;
 286     SkVector scale = SkVector::Make(fScale, fScale);
 287     ctm.mapVectors(&scale, 1);
 288     bounds.outset(SkScalarCeilToInt(scale.fX * SK_ScalarHalf),
 289                   SkScalarCeilToInt(scale.fY * SK_ScalarHalf));
 290     if (getColorInput()) {
 291         return getColorInput()->filterBounds(bounds, ctm, dst);
 292     }
 293     *dst = bounds;
 294     return true;
 295 }
 296
 297 ///////////////////////////////////////////////////////////////////////////////
 298
 299 #if SK_SUPPORT_GPU
 300 class GrGLDisplacementMapEffect : public GrGLFragmentProcessor {
 301 public:
 302     GrGLDisplacementMapEffect(const GrBackendProcessorFactory&,
 303                               const GrProcessor&);
 304     virtual ~GrGLDisplacementMapEffect();
 305
 306     virtual void emitCode(GrGLProgramBuilder*,
 307                           const GrFragmentProcessor&,
 308                           const GrProcessorKey&,
 309                           const char* outputColor,
 310                           const char* inputColor,
 311                           const TransformedCoordsArray&,
 312                           const TextureSamplerArray&) SK_OVERRIDE;
 313
 314     static inline void GenKey(const GrProcessor&, const GrGLCaps&, GrProcessorKeyBuilder*);
 315
 316     virtual void setData(const GrGLProgramDataManager&, const GrProcessor&) SK_OVERRIDE;
 317
 318 private:
 319     SkDisplacementMapEffect::ChannelSelectorType fXChannelSelector;
 320     SkDisplacementMapEffect::ChannelSelectorType fYChannelSelector;
 321     GrGLProgramDataManager::UniformHandle fScaleUni;
 322
 323     typedef GrGLFragmentProcessor INHERITED;
 324 };
 325
 326 ///////////////////////////////////////////////////////////////////////////////
 327
 328 class GrDisplacementMapEffect : public GrFragmentProcessor {
 329 public:
 330     static GrFragmentProcessor* Create(
 331             SkDisplacementMapEffect::ChannelSelectorType xChannelSelector,
 332             SkDisplacementMapEffect::ChannelSelectorType yChannelSelector, SkVector scale,
 333             GrTexture* displacement, const SkMatrix& offsetMatrix, GrTexture* color) {
 334         return SkNEW_ARGS(GrDisplacementMapEffect, (xChannelSelector,
 335                                                     yChannelSelector,
 336                                                     scale,
 337                                                     displacement,
 338                                                     offsetMatrix,
 339                                                     color));
 340     }
 341
 342     virtual ~GrDisplacementMapEffect();
 343
 344     virtual const GrBackendFragmentProcessorFactory& getFactory() const SK_OVERRIDE;
 345     SkDisplacementMapEffect::ChannelSelectorType xChannelSelector() const
 346         { return fXChannelSelector; }
 347     SkDisplacementMapEffect::ChannelSelectorType yChannelSelector() const
 348         { return fYChannelSelector; }
 349     const SkVector& scale() const { return fScale; }
 350
 351     typedef GrGLDisplacementMapEffect GLProcessor;
 352     static const char* Name() { return "DisplacementMap"; }
 353
 354     virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE;
 355
 356 private:
 357     virtual bool onIsEqual(const GrProcessor&) const SK_OVERRIDE;
 358
 359     GrDisplacementMapEffect(SkDisplacementMapEffect::ChannelSelectorType xChannelSelector,
 360                             SkDisplacementMapEffect::ChannelSelectorType yChannelSelector,
 361                             const SkVector& scale,
 362                             GrTexture* displacement, const SkMatrix& offsetMatrix,
 363                             GrTexture* color);
 364
 365     GR_DECLARE_FRAGMENT_PROCESSOR_TEST;
 366
 367     GrCoordTransform            fDisplacementTransform;
 368     GrTextureAccess             fDisplacementAccess;
 369     GrCoordTransform            fColorTransform;
 370     GrTextureAccess             fColorAccess;
 371     SkDisplacementMapEffect::ChannelSelectorType fXChannelSelector;
 372     SkDisplacementMapEffect::ChannelSelectorType fYChannelSelector;
 373     SkVector fScale;
 374
 375     typedef GrFragmentProcessor INHERITED;
 376 };
 377
 378 bool SkDisplacementMapEffect::filterImageGPU(Proxy* proxy, const SkBitmap& src, const Context& ctx,
 379                                              SkBitmap* result, SkIPoint* offset) const {
 380     SkBitmap colorBM = src;
 381     SkIPoint colorOffset = SkIPoint::Make(0, 0);
 382     if (getColorInput() && !getColorInput()->getInputResultGPU(proxy, src, ctx, &colorBM,
 383                                                                &colorOffset)) {
 384         return false;
 385     }
 386     SkBitmap displacementBM = src;
 387     SkIPoint displacementOffset = SkIPoint::Make(0, 0);
 388     if (getDisplacementInput() &&
 389         !getDisplacementInput()->getInputResultGPU(proxy, src, ctx, &displacementBM,
 390                                                    &displacementOffset)) {
 391         return false;
 392     }
 393     SkIRect bounds;
 394     // Since GrDisplacementMapEffect does bounds checking on color pixel access, we don't need to
 395     // pad the color bitmap to bounds here.
 396     if (!this->applyCropRect(ctx, colorBM, colorOffset, &bounds)) {
 397         return false;
 398     }
 399     SkIRect displBounds;
 400     if (!this->applyCropRect(ctx, proxy, displacementBM,
 401                              &displacementOffset, &displBounds, &displacementBM)) {
 402         return false;
 403     }
 404     if (!bounds.intersect(displBounds)) {
 405         return false;
 406     }
 407     GrTexture* color = colorBM.getTexture();
 408     GrTexture* displacement = displacementBM.getTexture();
 409     GrContext* context = color->getContext();
 410
 411     GrTextureDesc desc;
 412     desc.fFlags = kRenderTarget_GrTextureFlagBit | kNoStencil_GrTextureFlagBit;
 413     desc.fWidth = bounds.width();
 414     desc.fHeight = bounds.height();
 415     desc.fConfig = kSkia8888_GrPixelConfig;
 416
 417     GrAutoScratchTexture ast(context, desc);
 418     if (NULL == ast.texture()) {
 419         return false;
 420     }
 421     SkAutoTUnref<GrTexture> dst(ast.detach());
 422
 423     GrContext::AutoRenderTarget art(context, dst->asRenderTarget());
 424
 425     SkVector scale = SkVector::Make(fScale, fScale);
 426     ctx.ctm().mapVectors(&scale, 1);
 427
 428     GrPaint paint;
 429     SkMatrix offsetMatrix = GrCoordTransform::MakeDivByTextureWHMatrix(displacement);
 430     offsetMatrix.preTranslate(SkIntToScalar(colorOffset.fX - displacementOffset.fX),
 431                               SkIntToScalar(colorOffset.fY - displacementOffset.fY));
 432
 433     paint.addColorProcessor(
 434         GrDisplacementMapEffect::Create(fXChannelSelector,
 435                                         fYChannelSelector,
 436                                         scale,
 437                                         displacement,
 438                                         offsetMatrix,
 439                                         color))->unref();
 440     SkIRect colorBounds = bounds;
 441     colorBounds.offset(-colorOffset);
 442     GrContext::AutoMatrix am;
 443     am.setIdentity(context);
 444     SkMatrix matrix;
 445     matrix.setTranslate(-SkIntToScalar(colorBounds.x()),
 446                         -SkIntToScalar(colorBounds.y()));
 447     context->concatMatrix(matrix);
 448     context->drawRect(paint, SkRect::Make(colorBounds));
 449     offset->fX = bounds.left();
 450     offset->fY = bounds.top();
 451     WrapTexture(dst, bounds.width(), bounds.height(), result);
 452     return true;
 453 }
 454
 455 ///////////////////////////////////////////////////////////////////////////////
 456
 457 GrDisplacementMapEffect::GrDisplacementMapEffect(
 458                              SkDisplacementMapEffect::ChannelSelectorType xChannelSelector,
 459                              SkDisplacementMapEffect::ChannelSelectorType yChannelSelector,
 460                              const SkVector& scale,
 461                              GrTexture* displacement,
 462                              const SkMatrix& offsetMatrix,
 463                              GrTexture* color)
 464     : fDisplacementTransform(kLocal_GrCoordSet, offsetMatrix, displacement)
 465     , fDisplacementAccess(displacement)
 466     , fColorTransform(kLocal_GrCoordSet, color)
 467     , fColorAccess(color)
 468     , fXChannelSelector(xChannelSelector)
 469     , fYChannelSelector(yChannelSelector)
 470     , fScale(scale) {
 471     this->addCoordTransform(&fDisplacementTransform);
 472     this->addTextureAccess(&fDisplacementAccess);
 473     this->addCoordTransform(&fColorTransform);
 474     this->addTextureAccess(&fColorAccess);
 475     this->setWillNotUseInputColor();
 476 }
 477
 478 GrDisplacementMapEffect::~GrDisplacementMapEffect() {
 479 }
 480
 481 bool GrDisplacementMapEffect::onIsEqual(const GrProcessor& sBase) const {
 482     const GrDisplacementMapEffect& s = sBase.cast<GrDisplacementMapEffect>();
 483     return fDisplacementAccess.getTexture() == s.fDisplacementAccess.getTexture() &&
 484            fColorAccess.getTexture() == s.fColorAccess.getTexture() &&
 485            fXChannelSelector == s.fXChannelSelector &&
 486            fYChannelSelector == s.fYChannelSelector &&
 487            fScale == s.fScale;
 488 }
 489
 490 const GrBackendFragmentProcessorFactory& GrDisplacementMapEffect::getFactory() const {
 491     return GrTBackendFragmentProcessorFactory<GrDisplacementMapEffect>::getInstance();
 492 }
 493
 494 void GrDisplacementMapEffect::getConstantColorComponents(GrColor*,
 495                                                          uint32_t* validFlags) const {
 496     // Any displacement offset bringing a pixel out of bounds will output a color of (0,0,0,0),
 497     // so the only way we'd get a constant alpha is if the input color image has a constant alpha
 498     // and no displacement offset push any texture coordinates out of bounds OR if the constant
 499     // alpha is 0. Since this isn't trivial to compute at this point, let's assume the output is
 500     // not of constant color when a displacement effect is applied.
 501     *validFlags = 0;
 502 }
 503
 504 ///////////////////////////////////////////////////////////////////////////////
 505
 506 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrDisplacementMapEffect);
 507
 508 GrFragmentProcessor* GrDisplacementMapEffect::TestCreate(SkRandom* random,
 509                                               GrContext*,
 510                                               const GrDrawTargetCaps&,
 511                                               GrTexture* textures[]) {
 512     int texIdxDispl = random->nextBool() ? GrProcessorUnitTest::kSkiaPMTextureIdx :
 513                                            GrProcessorUnitTest::kAlphaTextureIdx;
 514     int texIdxColor = random->nextBool() ? GrProcessorUnitTest::kSkiaPMTextureIdx :
 515                                            GrProcessorUnitTest::kAlphaTextureIdx;
 516     static const int kMaxComponent = 4;
 517     SkDisplacementMapEffect::ChannelSelectorType xChannelSelector =
 518         static_cast<SkDisplacementMapEffect::ChannelSelectorType>(
 519         random->nextRangeU(1, kMaxComponent));
 520     SkDisplacementMapEffect::ChannelSelectorType yChannelSelector =
 521         static_cast<SkDisplacementMapEffect::ChannelSelectorType>(
 522         random->nextRangeU(1, kMaxComponent));
 523     SkVector scale = SkVector::Make(random->nextRangeScalar(0, 100.0f),
 524                                     random->nextRangeScalar(0, 100.0f));
 525
 526     return GrDisplacementMapEffect::Create(xChannelSelector, yChannelSelector, scale,
 527                                            textures[texIdxDispl], SkMatrix::I(),
 528                                            textures[texIdxColor]);
 529 }
 530
 531 ///////////////////////////////////////////////////////////////////////////////
 532
 533 GrGLDisplacementMapEffect::GrGLDisplacementMapEffect(const GrBackendProcessorFactory& factory,
 534                                                      const GrProcessor& proc)
 535     : INHERITED(factory)
 536     , fXChannelSelector(proc.cast<GrDisplacementMapEffect>().xChannelSelector())
 537     , fYChannelSelector(proc.cast<GrDisplacementMapEffect>().yChannelSelector()) {
 538 }
 539
 540 GrGLDisplacementMapEffect::~GrGLDisplacementMapEffect() {
 541 }
 542
 543 void GrGLDisplacementMapEffect::emitCode(GrGLProgramBuilder* builder,
 544                                          const GrFragmentProcessor&,
 545                                          const GrProcessorKey& key,
 546                                          const char* outputColor,
 547                                          const char* inputColor,
 548                                          const TransformedCoordsArray& coords,
 549                                          const TextureSamplerArray& samplers) {
 550     sk_ignore_unused_variable(inputColor);
 551
 552     fScaleUni = builder->addUniform(GrGLProgramBuilder::kFragment_Visibility,
 553                                     kVec2f_GrSLType, "Scale");
 554     const char* scaleUni = builder->getUniformCStr(fScaleUni);
 555     const char* dColor = "dColor";
 556     const char* cCoords = "cCoords";
 557     const char* outOfBounds = "outOfBounds";
 558     const char* nearZero = "1e-6"; // Since 6.10352e−5 is the smallest half float, use
 559                                    // a number smaller than that to approximate 0, but
 560                                    // leave room for 32-bit float GPU rounding errors.
 561
 562     GrGLFragmentShaderBuilder* fsBuilder = builder->getFragmentShaderBuilder();
 563     fsBuilder->codeAppendf("\t\tvec4 %s = ", dColor);
 564     fsBuilder->appendTextureLookup(samplers[0], coords[0].c_str(), coords[0].getType());
 565     fsBuilder->codeAppend(";\n");
 566
 567     // Unpremultiply the displacement
 568     fsBuilder->codeAppendf("\t\t%s.rgb = (%s.a < %s) ? vec3(0.0) : clamp(%s.rgb / %s.a, 0.0, 1.0);",
 569                            dColor, dColor, nearZero, dColor, dColor);
 570
 571     fsBuilder->codeAppendf("\t\tvec2 %s = %s + %s*(%s.",
 572                            cCoords, coords[1].c_str(), scaleUni, dColor);
 573
 574     switch (fXChannelSelector) {
 575       case SkDisplacementMapEffect::kR_ChannelSelectorType:
 576         fsBuilder->codeAppend("r");
 577         break;
 578       case SkDisplacementMapEffect::kG_ChannelSelectorType:
 579         fsBuilder->codeAppend("g");
 580         break;
 581       case SkDisplacementMapEffect::kB_ChannelSelectorType:
 582         fsBuilder->codeAppend("b");
 583         break;
 584       case SkDisplacementMapEffect::kA_ChannelSelectorType:
 585         fsBuilder->codeAppend("a");
 586         break;
 587       case SkDisplacementMapEffect::kUnknown_ChannelSelectorType:
 588       default:
 589         SkDEBUGFAIL("Unknown X channel selector");
 590     }
 591
 592     switch (fYChannelSelector) {
 593       case SkDisplacementMapEffect::kR_ChannelSelectorType:
 594         fsBuilder->codeAppend("r");
 595         break;
 596       case SkDisplacementMapEffect::kG_ChannelSelectorType:
 597         fsBuilder->codeAppend("g");
 598         break;
 599       case SkDisplacementMapEffect::kB_ChannelSelectorType:
 600         fsBuilder->codeAppend("b");
 601         break;
 602       case SkDisplacementMapEffect::kA_ChannelSelectorType:
 603         fsBuilder->codeAppend("a");
 604         break;
 605       case SkDisplacementMapEffect::kUnknown_ChannelSelectorType:
 606       default:
 607         SkDEBUGFAIL("Unknown Y channel selector");
 608     }
 609     fsBuilder->codeAppend("-vec2(0.5));\t\t");
 610
 611     // FIXME : This can be achieved with a "clamp to border" texture repeat mode and
 612     //         a 0 border color instead of computing if cCoords is out of bounds here.
 613     fsBuilder->codeAppendf(
 614         "bool %s = (%s.x < 0.0) || (%s.y < 0.0) || (%s.x > 1.0) || (%s.y > 1.0);\t\t",
 615         outOfBounds, cCoords, cCoords, cCoords, cCoords);
 616     fsBuilder->codeAppendf("%s = %s ? vec4(0.0) : ", outputColor, outOfBounds);
 617     fsBuilder->appendTextureLookup(samplers[1], cCoords, coords[1].getType());
 618     fsBuilder->codeAppend(";\n");
 619 }
 620
 621 void GrGLDisplacementMapEffect::setData(const GrGLProgramDataManager& pdman,
 622                                         const GrProcessor& proc) {
 623     const GrDisplacementMapEffect& displacementMap = proc.cast<GrDisplacementMapEffect>();
 624     GrTexture* colorTex = displacementMap.texture(1);
 625     SkScalar scaleX = SkScalarDiv(displacementMap.scale().fX, SkIntToScalar(colorTex->width()));
 626     SkScalar scaleY = SkScalarDiv(displacementMap.scale().fY, SkIntToScalar(colorTex->height()));
 627     pdman.set2f(fScaleUni, SkScalarToFloat(scaleX),
 628                 colorTex->origin() == kTopLeft_GrSurfaceOrigin ?
 629                 SkScalarToFloat(scaleY) : SkScalarToFloat(-scaleY));
 630 }
 631
 632 void GrGLDisplacementMapEffect::GenKey(const GrProcessor& proc,
 633                                        const GrGLCaps&, GrProcessorKeyBuilder* b) {
 634     const GrDisplacementMapEffect& displacementMap = proc.cast<GrDisplacementMapEffect>();
 635
 636     uint32_t xKey = displacementMap.xChannelSelector();
 637     uint32_t yKey = displacementMap.yChannelSelector() << kChannelSelectorKeyBits;
 638
 639     b->add32(xKey | yKey);
 640 }
 641 #endif