src/third_party/skia/src/gpu/effects/GrConfigConversionEffect.cpp

   1 /*
   2  * Copyright 2012 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 "GrConfigConversionEffect.h"
   9 #include "GrContext.h"
  10 #include "GrTBackendEffectFactory.h"
  11 #include "GrSimpleTextureEffect.h"
  12 #include "gl/GrGLEffect.h"
  13 #include "gl/GrGLShaderBuilder.h"
  14 #include "SkMatrix.h"
  15
  16 class GrGLConfigConversionEffect : public GrGLEffect {
  17 public:
  18     GrGLConfigConversionEffect(const GrBackendEffectFactory& factory,
  19                                const GrDrawEffect& drawEffect)
  20     : INHERITED (factory) {
  21         const GrConfigConversionEffect& effect = drawEffect.castEffect<GrConfigConversionEffect>();
  22         fSwapRedAndBlue = effect.swapsRedAndBlue();
  23         fPMConversion = effect.pmConversion();
  24     }
  25
  26     virtual void emitCode(GrGLShaderBuilder* builder,
  27                           const GrDrawEffect&,
  28                           const GrEffectKey& key,
  29                           const char* outputColor,
  30                           const char* inputColor,
  31                           const TransformedCoordsArray& coords,
  32                           const TextureSamplerArray& samplers) SK_OVERRIDE {
  33         builder->fsCodeAppendf("\t\t%s = ", outputColor);
  34         builder->fsAppendTextureLookup(samplers[0], coords[0].c_str(), coords[0].type());
  35         builder->fsCodeAppend(";\n");
  36         if (GrConfigConversionEffect::kNone_PMConversion == fPMConversion) {
  37             SkASSERT(fSwapRedAndBlue);
  38             builder->fsCodeAppendf("\t%s = %s.bgra;\n", outputColor, outputColor);
  39         } else {
  40             const char* swiz = fSwapRedAndBlue ? "bgr" : "rgb";
  41             switch (fPMConversion) {
  42                 case GrConfigConversionEffect::kMulByAlpha_RoundUp_PMConversion:
  43                     builder->fsCodeAppendf(
  44                         "\t\t%s = vec4(ceil(%s.%s * %s.a * 255.0) / 255.0, %s.a);\n",
  45                         outputColor, outputColor, swiz, outputColor, outputColor);
  46                     break;
  47                 case GrConfigConversionEffect::kMulByAlpha_RoundDown_PMConversion:
  48                     // Add a compensation(0.001) here to avoid the side effect of the floor operation.
  49                     // In Intel GPUs, the integer value converted from floor(%s.r * 255.0) / 255.0
  50                     // is less than the integer value converted from  %s.r by 1 when the %s.r is
  51                     // converted from the integer value 2^n, such as 1, 2, 4, 8, etc.
  52                     builder->fsCodeAppendf(
  53                         "\t\t%s = vec4(floor(%s.%s * %s.a * 255.0 + 0.001) / 255.0, %s.a);\n",
  54                         outputColor, outputColor, swiz, outputColor, outputColor);
  55                     break;
  56                 case GrConfigConversionEffect::kDivByAlpha_RoundUp_PMConversion:
  57                     builder->fsCodeAppendf("\t\t%s = %s.a <= 0.0 ? vec4(0,0,0,0) : vec4(ceil(%s.%s / %s.a * 255.0) / 255.0, %s.a);\n",
  58                         outputColor, outputColor, outputColor, swiz, outputColor, outputColor);
  59                     break;
  60                 case GrConfigConversionEffect::kDivByAlpha_RoundDown_PMConversion:
  61                     builder->fsCodeAppendf("\t\t%s = %s.a <= 0.0 ? vec4(0,0,0,0) : vec4(floor(%s.%s / %s.a * 255.0) / 255.0, %s.a);\n",
  62                         outputColor, outputColor, outputColor, swiz, outputColor, outputColor);
  63                     break;
  64                 default:
  65                     SkFAIL("Unknown conversion op.");
  66                     break;
  67             }
  68         }
  69         SkString modulate;
  70         GrGLSLMulVarBy4f(&modulate, 2, outputColor, inputColor);
  71         builder->fsCodeAppend(modulate.c_str());
  72     }
  73
  74     static inline void GenKey(const GrDrawEffect& drawEffect, const GrGLCaps&,
  75                               GrEffectKeyBuilder* b) {
  76         const GrConfigConversionEffect& conv = drawEffect.castEffect<GrConfigConversionEffect>();
  77         uint32_t key = (conv.swapsRedAndBlue() ? 0 : 1) | (conv.pmConversion() << 1);
  78         b->add32(key);
  79     }
  80
  81 private:
  82     bool                                    fSwapRedAndBlue;
  83     GrConfigConversionEffect::PMConversion  fPMConversion;
  84
  85     typedef GrGLEffect INHERITED;
  86
  87 };
  88
  89 ///////////////////////////////////////////////////////////////////////////////
  90
  91 GrConfigConversionEffect::GrConfigConversionEffect(GrTexture* texture,
  92                                                    bool swapRedAndBlue,
  93                                                    PMConversion pmConversion,
  94                                                    const SkMatrix& matrix)
  95     : GrSingleTextureEffect(texture, matrix)
  96     , fSwapRedAndBlue(swapRedAndBlue)
  97     , fPMConversion(pmConversion) {
  98     SkASSERT(kRGBA_8888_GrPixelConfig == texture->config() ||
  99              kBGRA_8888_GrPixelConfig == texture->config());
 100     // Why did we pollute our texture cache instead of using a GrSingleTextureEffect?
 101     SkASSERT(swapRedAndBlue || kNone_PMConversion != pmConversion);
 102 }
 103
 104 const GrBackendEffectFactory& GrConfigConversionEffect::getFactory() const {
 105     return GrTBackendEffectFactory<GrConfigConversionEffect>::getInstance();
 106 }
 107
 108 bool GrConfigConversionEffect::onIsEqual(const GrEffect& s) const {
 109     const GrConfigConversionEffect& other = CastEffect<GrConfigConversionEffect>(s);
 110     return this->texture(0) == s.texture(0) &&
 111            other.fSwapRedAndBlue == fSwapRedAndBlue &&
 112            other.fPMConversion == fPMConversion;
 113 }
 114
 115 void GrConfigConversionEffect::getConstantColorComponents(GrColor* color,
 116                                                           uint32_t* validFlags) const {
 117     this->updateConstantColorComponentsForModulation(color, validFlags);
 118 }
 119
 120 ///////////////////////////////////////////////////////////////////////////////
 121
 122 GR_DEFINE_EFFECT_TEST(GrConfigConversionEffect);
 123
 124 GrEffect* GrConfigConversionEffect::TestCreate(SkRandom* random,
 125                                                GrContext*,
 126                                                const GrDrawTargetCaps&,
 127                                                GrTexture* textures[]) {
 128     PMConversion pmConv = static_cast<PMConversion>(random->nextULessThan(kPMConversionCnt));
 129     bool swapRB;
 130     if (kNone_PMConversion == pmConv) {
 131         swapRB = true;
 132     } else {
 133         swapRB = random->nextBool();
 134     }
 135     return SkNEW_ARGS(GrConfigConversionEffect,
 136                                       (textures[GrEffectUnitTest::kSkiaPMTextureIdx],
 137                                        swapRB,
 138                                        pmConv,
 139                                        GrEffectUnitTest::TestMatrix(random)));
 140 }
 141
 142 ///////////////////////////////////////////////////////////////////////////////
 143 void GrConfigConversionEffect::TestForPreservingPMConversions(GrContext* context,
 144                                                               PMConversion* pmToUPMRule,
 145                                                               PMConversion* upmToPMRule) {
 146     *pmToUPMRule = kNone_PMConversion;
 147     *upmToPMRule = kNone_PMConversion;
 148     SkAutoTMalloc<uint32_t> data(256 * 256 * 3);
 149     uint32_t* srcData = data.get();
 150     uint32_t* firstRead = data.get() + 256 * 256;
 151     uint32_t* secondRead = data.get() + 2 * 256 * 256;
 152
 153     // Fill with every possible premultiplied A, color channel value. There will be 256-y duplicate
 154     // values in row y. We set r,g, and b to the same value since they are handled identically.
 155     for (int y = 0; y < 256; ++y) {
 156         for (int x = 0; x < 256; ++x) {
 157             uint8_t* color = reinterpret_cast<uint8_t*>(&srcData[256*y + x]);
 158             color[3] = y;
 159             color[2] = SkTMin(x, y);
 160             color[1] = SkTMin(x, y);
 161             color[0] = SkTMin(x, y);
 162         }
 163     }
 164
 165     GrTextureDesc desc;
 166     desc.fFlags = kRenderTarget_GrTextureFlagBit |
 167                   kNoStencil_GrTextureFlagBit;
 168     desc.fWidth = 256;
 169     desc.fHeight = 256;
 170     desc.fConfig = kRGBA_8888_GrPixelConfig;
 171
 172     SkAutoTUnref<GrTexture> readTex(context->createUncachedTexture(desc, NULL, 0));
 173     if (!readTex.get()) {
 174         return;
 175     }
 176     SkAutoTUnref<GrTexture> tempTex(context->createUncachedTexture(desc, NULL, 0));
 177     if (!tempTex.get()) {
 178         return;
 179     }
 180     desc.fFlags = kNone_GrTextureFlags;
 181     SkAutoTUnref<GrTexture> dataTex(context->createUncachedTexture(desc, data, 0));
 182     if (!dataTex.get()) {
 183         return;
 184     }
 185
 186     static const PMConversion kConversionRules[][2] = {
 187         {kDivByAlpha_RoundDown_PMConversion, kMulByAlpha_RoundUp_PMConversion},
 188         {kDivByAlpha_RoundUp_PMConversion, kMulByAlpha_RoundDown_PMConversion},
 189     };
 190
 191     GrContext::AutoWideOpenIdentityDraw awoid(context, NULL);
 192
 193     bool failed = true;
 194
 195     for (size_t i = 0; i < SK_ARRAY_COUNT(kConversionRules) && failed; ++i) {
 196         *pmToUPMRule = kConversionRules[i][0];
 197         *upmToPMRule = kConversionRules[i][1];
 198
 199         static const SkRect kDstRect = SkRect::MakeWH(SkIntToScalar(256), SkIntToScalar(256));
 200         static const SkRect kSrcRect = SkRect::MakeWH(SK_Scalar1, SK_Scalar1);
 201         // We do a PM->UPM draw from dataTex to readTex and read the data. Then we do a UPM->PM draw
 202         // from readTex to tempTex followed by a PM->UPM draw to readTex and finally read the data.
 203         // We then verify that two reads produced the same values.
 204
 205         SkAutoTUnref<GrEffect> pmToUPM1(SkNEW_ARGS(GrConfigConversionEffect, (dataTex,
 206                                                                               false,
 207                                                                               *pmToUPMRule,
 208                                                                               SkMatrix::I())));
 209         SkAutoTUnref<GrEffect> upmToPM(SkNEW_ARGS(GrConfigConversionEffect, (readTex,
 210                                                                              false,
 211                                                                              *upmToPMRule,
 212                                                                              SkMatrix::I())));
 213         SkAutoTUnref<GrEffect> pmToUPM2(SkNEW_ARGS(GrConfigConversionEffect, (tempTex,
 214                                                                               false,
 215                                                                               *pmToUPMRule,
 216                                                                               SkMatrix::I())));
 217
 218         context->setRenderTarget(readTex->asRenderTarget());
 219         GrPaint paint1;
 220         paint1.addColorEffect(pmToUPM1);
 221         context->drawRectToRect(paint1, kDstRect, kSrcRect);
 222
 223         readTex->readPixels(0, 0, 256, 256, kRGBA_8888_GrPixelConfig, firstRead);
 224
 225         context->setRenderTarget(tempTex->asRenderTarget());
 226         GrPaint paint2;
 227         paint2.addColorEffect(upmToPM);
 228         context->drawRectToRect(paint2, kDstRect, kSrcRect);
 229         context->setRenderTarget(readTex->asRenderTarget());
 230
 231         GrPaint paint3;
 232         paint3.addColorEffect(pmToUPM2);
 233         context->drawRectToRect(paint3, kDstRect, kSrcRect);
 234
 235         readTex->readPixels(0, 0, 256, 256, kRGBA_8888_GrPixelConfig, secondRead);
 236
 237         failed = false;
 238         for (int y = 0; y < 256 && !failed; ++y) {
 239             for (int x = 0; x <= y; ++x) {
 240                 if (firstRead[256 * y + x] != secondRead[256 * y + x]) {
 241                     failed = true;
 242                     break;
 243                 }
 244             }
 245         }
 246     }
 247     if (failed) {
 248         *pmToUPMRule = kNone_PMConversion;
 249         *upmToPMRule = kNone_PMConversion;
 250     }
 251 }
 252
 253 const GrEffect* GrConfigConversionEffect::Create(GrTexture* texture,
 254                                                  bool swapRedAndBlue,
 255                                                  PMConversion pmConversion,
 256                                                  const SkMatrix& matrix) {
 257     if (!swapRedAndBlue && kNone_PMConversion == pmConversion) {
 258         // If we returned a GrConfigConversionEffect that was equivalent to a GrSimpleTextureEffect
 259         // then we may pollute our texture cache with redundant shaders. So in the case that no
 260         // conversions were requested we instead return a GrSimpleTextureEffect.
 261         return GrSimpleTextureEffect::Create(texture, matrix);
 262     } else {
 263         if (kRGBA_8888_GrPixelConfig != texture->config() &&
 264             kBGRA_8888_GrPixelConfig != texture->config() &&
 265             kNone_PMConversion != pmConversion) {
 266             // The PM conversions assume colors are 0..255
 267             return NULL;
 268         }
 269         return SkNEW_ARGS(GrConfigConversionEffect, (texture,
 270                                                      swapRedAndBlue,
 271                                                      pmConversion,
 272                                                      matrix));
 273     }
 274 }