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                           EffectKey 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 EffectKey GenKey(const GrDrawEffect& drawEffect, const GrGLCaps&) {
  75         const GrConfigConversionEffect& conv = drawEffect.castEffect<GrConfigConversionEffect>();
  76         return static_cast<EffectKey>(conv.swapsRedAndBlue()) | (conv.pmConversion() << 1);
  77     }
  78
  79 private:
  80     bool                                    fSwapRedAndBlue;
  81     GrConfigConversionEffect::PMConversion  fPMConversion;
  82
  83     typedef GrGLEffect INHERITED;
  84
  85 };
  86
  87 ///////////////////////////////////////////////////////////////////////////////
  88
  89 GrConfigConversionEffect::GrConfigConversionEffect(GrTexture* texture,
  90                                                    bool swapRedAndBlue,
  91                                                    PMConversion pmConversion,
  92                                                    const SkMatrix& matrix)
  93     : GrSingleTextureEffect(texture, matrix)
  94     , fSwapRedAndBlue(swapRedAndBlue)
  95     , fPMConversion(pmConversion) {
  96     SkASSERT(kRGBA_8888_GrPixelConfig == texture->config() ||
  97              kBGRA_8888_GrPixelConfig == texture->config());
  98     // Why did we pollute our texture cache instead of using a GrSingleTextureEffect?
  99     SkASSERT(swapRedAndBlue || kNone_PMConversion != pmConversion);
 100 }
 101
 102 const GrBackendEffectFactory& GrConfigConversionEffect::getFactory() const {
 103     return GrTBackendEffectFactory<GrConfigConversionEffect>::getInstance();
 104 }
 105
 106 bool GrConfigConversionEffect::onIsEqual(const GrEffect& s) const {
 107     const GrConfigConversionEffect& other = CastEffect<GrConfigConversionEffect>(s);
 108     return this->texture(0) == s.texture(0) &&
 109            other.fSwapRedAndBlue == fSwapRedAndBlue &&
 110            other.fPMConversion == fPMConversion;
 111 }
 112
 113 void GrConfigConversionEffect::getConstantColorComponents(GrColor* color,
 114                                                           uint32_t* validFlags) const {
 115     this->updateConstantColorComponentsForModulation(color, validFlags);
 116 }
 117
 118 ///////////////////////////////////////////////////////////////////////////////
 119
 120 GR_DEFINE_EFFECT_TEST(GrConfigConversionEffect);
 121
 122 GrEffect* GrConfigConversionEffect::TestCreate(SkRandom* random,
 123                                                GrContext*,
 124                                                const GrDrawTargetCaps&,
 125                                                GrTexture* textures[]) {
 126     PMConversion pmConv = static_cast<PMConversion>(random->nextULessThan(kPMConversionCnt));
 127     bool swapRB;
 128     if (kNone_PMConversion == pmConv) {
 129         swapRB = true;
 130     } else {
 131         swapRB = random->nextBool();
 132     }
 133     return SkNEW_ARGS(GrConfigConversionEffect,
 134                                       (textures[GrEffectUnitTest::kSkiaPMTextureIdx],
 135                                        swapRB,
 136                                        pmConv,
 137                                        GrEffectUnitTest::TestMatrix(random)));
 138 }
 139
 140 ///////////////////////////////////////////////////////////////////////////////
 141 void GrConfigConversionEffect::TestForPreservingPMConversions(GrContext* context,
 142                                                               PMConversion* pmToUPMRule,
 143                                                               PMConversion* upmToPMRule) {
 144     *pmToUPMRule = kNone_PMConversion;
 145     *upmToPMRule = kNone_PMConversion;
 146     SkAutoTMalloc<uint32_t> data(256 * 256 * 3);
 147     uint32_t* srcData = data.get();
 148     uint32_t* firstRead = data.get() + 256 * 256;
 149     uint32_t* secondRead = data.get() + 2 * 256 * 256;
 150
 151     // Fill with every possible premultiplied A, color channel value. There will be 256-y duplicate
 152     // values in row y. We set r,g, and b to the same value since they are handled identically.
 153     for (int y = 0; y < 256; ++y) {
 154         for (int x = 0; x < 256; ++x) {
 155             uint8_t* color = reinterpret_cast<uint8_t*>(&srcData[256*y + x]);
 156             color[3] = y;
 157             color[2] = SkTMin(x, y);
 158             color[1] = SkTMin(x, y);
 159             color[0] = SkTMin(x, y);
 160         }
 161     }
 162
 163     GrTextureDesc desc;
 164     desc.fFlags = kRenderTarget_GrTextureFlagBit |
 165                   kNoStencil_GrTextureFlagBit;
 166     desc.fWidth = 256;
 167     desc.fHeight = 256;
 168     desc.fConfig = kRGBA_8888_GrPixelConfig;
 169
 170     SkAutoTUnref<GrTexture> readTex(context->createUncachedTexture(desc, NULL, 0));
 171     if (!readTex.get()) {
 172         return;
 173     }
 174     SkAutoTUnref<GrTexture> tempTex(context->createUncachedTexture(desc, NULL, 0));
 175     if (!tempTex.get()) {
 176         return;
 177     }
 178     desc.fFlags = kNone_GrTextureFlags;
 179     SkAutoTUnref<GrTexture> dataTex(context->createUncachedTexture(desc, data, 0));
 180     if (!dataTex.get()) {
 181         return;
 182     }
 183
 184     static const PMConversion kConversionRules[][2] = {
 185         {kDivByAlpha_RoundDown_PMConversion, kMulByAlpha_RoundUp_PMConversion},
 186         {kDivByAlpha_RoundUp_PMConversion, kMulByAlpha_RoundDown_PMConversion},
 187     };
 188
 189     GrContext::AutoWideOpenIdentityDraw awoid(context, NULL);
 190
 191     bool failed = true;
 192
 193     for (size_t i = 0; i < SK_ARRAY_COUNT(kConversionRules) && failed; ++i) {
 194         *pmToUPMRule = kConversionRules[i][0];
 195         *upmToPMRule = kConversionRules[i][1];
 196
 197         static const SkRect kDstRect = SkRect::MakeWH(SkIntToScalar(256), SkIntToScalar(256));
 198         static const SkRect kSrcRect = SkRect::MakeWH(SK_Scalar1, SK_Scalar1);
 199         // We do a PM->UPM draw from dataTex to readTex and read the data. Then we do a UPM->PM draw
 200         // from readTex to tempTex followed by a PM->UPM draw to readTex and finally read the data.
 201         // We then verify that two reads produced the same values.
 202
 203         SkAutoTUnref<GrEffect> pmToUPM1(SkNEW_ARGS(GrConfigConversionEffect, (dataTex,
 204                                                                               false,
 205                                                                               *pmToUPMRule,
 206                                                                               SkMatrix::I())));
 207         SkAutoTUnref<GrEffect> upmToPM(SkNEW_ARGS(GrConfigConversionEffect, (readTex,
 208                                                                              false,
 209                                                                              *upmToPMRule,
 210                                                                              SkMatrix::I())));
 211         SkAutoTUnref<GrEffect> pmToUPM2(SkNEW_ARGS(GrConfigConversionEffect, (tempTex,
 212                                                                               false,
 213                                                                               *pmToUPMRule,
 214                                                                               SkMatrix::I())));
 215
 216         context->setRenderTarget(readTex->asRenderTarget());
 217         GrPaint paint1;
 218         paint1.addColorEffect(pmToUPM1);
 219         context->drawRectToRect(paint1, kDstRect, kSrcRect);
 220
 221         readTex->readPixels(0, 0, 256, 256, kRGBA_8888_GrPixelConfig, firstRead);
 222
 223         context->setRenderTarget(tempTex->asRenderTarget());
 224         GrPaint paint2;
 225         paint2.addColorEffect(upmToPM);
 226         context->drawRectToRect(paint2, kDstRect, kSrcRect);
 227         context->setRenderTarget(readTex->asRenderTarget());
 228
 229         GrPaint paint3;
 230         paint3.addColorEffect(pmToUPM2);
 231         context->drawRectToRect(paint3, kDstRect, kSrcRect);
 232
 233         readTex->readPixels(0, 0, 256, 256, kRGBA_8888_GrPixelConfig, secondRead);
 234
 235         failed = false;
 236         for (int y = 0; y < 256 && !failed; ++y) {
 237             for (int x = 0; x <= y; ++x) {
 238                 if (firstRead[256 * y + x] != secondRead[256 * y + x]) {
 239                     failed = true;
 240                     break;
 241                 }
 242             }
 243         }
 244     }
 245     if (failed) {
 246         *pmToUPMRule = kNone_PMConversion;
 247         *upmToPMRule = kNone_PMConversion;
 248     }
 249 }
 250
 251 const GrEffect* GrConfigConversionEffect::Create(GrTexture* texture,
 252                                                  bool swapRedAndBlue,
 253                                                  PMConversion pmConversion,
 254                                                  const SkMatrix& matrix) {
 255     if (!swapRedAndBlue && kNone_PMConversion == pmConversion) {
 256         // If we returned a GrConfigConversionEffect that was equivalent to a GrSimpleTextureEffect
 257         // then we may pollute our texture cache with redundant shaders. So in the case that no
 258         // conversions were requested we instead return a GrSimpleTextureEffect.
 259         return GrSimpleTextureEffect::Create(texture, matrix);
 260     } else {
 261         if (kRGBA_8888_GrPixelConfig != texture->config() &&
 262             kBGRA_8888_GrPixelConfig != texture->config() &&
 263             kNone_PMConversion != pmConversion) {
 264             // The PM conversions assume colors are 0..255
 265             return NULL;
 266         }
 267         return SkNEW_ARGS(GrConfigConversionEffect, (texture,
 268                                                      swapRedAndBlue,
 269                                                      pmConversion,
 270                                                      matrix));
 271     }
 272 }