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