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/builders/GrGLProgramBuilder.h"
  14 #include "SkMatrix.h"
  15
  16 class GrGLConfigConversionEffect : public GrGLEffect {
  17 public:
  18     GrGLConfigConversionEffect(const GrBackendEffectFactory& factory,
  19                                const GrEffect& effect)
  20     : INHERITED (factory) {
  21         const GrConfigConversionEffect& configConversionEffect = effect.cast<GrConfigConversionEffect>();
  22         fSwapRedAndBlue = configConversionEffect.swapsRedAndBlue();
  23         fPMConversion = configConversionEffect.pmConversion();
  24     }
  25
  26     virtual void emitCode(GrGLProgramBuilder* builder,
  27                           const GrEffect&,
  28                           const GrEffectKey& key,
  29                           const char* outputColor,
  30                           const char* inputColor,
  31                           const TransformedCoordsArray& coords,
  32                           const TextureSamplerArray& samplers) SK_OVERRIDE {
  33         // Using highp for GLES here in order to avoid some precision issues on specific GPUs.
  34         GrGLShaderVar tmpVar("tmpColor", kVec4f_GrSLType, 0, GrGLShaderVar::kHigh_Precision);
  35         SkString tmpDecl;
  36         tmpVar.appendDecl(builder->ctxInfo(), &tmpDecl);
  37
  38         GrGLFragmentShaderBuilder* fsBuilder = builder->getFragmentShaderBuilder();
  39
  40         fsBuilder->codeAppendf("%s;", tmpDecl.c_str());
  41
  42         fsBuilder->codeAppendf("%s = ", tmpVar.c_str());
  43         fsBuilder->appendTextureLookup(samplers[0], coords[0].c_str(), coords[0].getType());
  44         fsBuilder->codeAppend(";");
  45
  46         if (GrConfigConversionEffect::kNone_PMConversion == fPMConversion) {
  47             SkASSERT(fSwapRedAndBlue);
  48             fsBuilder->codeAppendf("%s = %s.bgra;", outputColor, tmpVar.c_str());
  49         } else {
  50             const char* swiz = fSwapRedAndBlue ? "bgr" : "rgb";
  51             switch (fPMConversion) {
  52                 case GrConfigConversionEffect::kMulByAlpha_RoundUp_PMConversion:
  53                     fsBuilder->codeAppendf(
  54                         "%s = vec4(ceil(%s.%s * %s.a * 255.0) / 255.0, %s.a);",
  55                         tmpVar.c_str(), tmpVar.c_str(), swiz, tmpVar.c_str(), tmpVar.c_str());
  56                     break;
  57                 case GrConfigConversionEffect::kMulByAlpha_RoundDown_PMConversion:
  58                     // Add a compensation(0.001) here to avoid the side effect of the floor operation.
  59                     // In Intel GPUs, the integer value converted from floor(%s.r * 255.0) / 255.0
  60                     // is less than the integer value converted from  %s.r by 1 when the %s.r is
  61                     // converted from the integer value 2^n, such as 1, 2, 4, 8, etc.
  62                     fsBuilder->codeAppendf(
  63                         "%s = vec4(floor(%s.%s * %s.a * 255.0 + 0.001) / 255.0, %s.a);",
  64                         tmpVar.c_str(), tmpVar.c_str(), swiz, tmpVar.c_str(), tmpVar.c_str());
  65                     break;
  66                 case GrConfigConversionEffect::kDivByAlpha_RoundUp_PMConversion:
  67                     fsBuilder->codeAppendf(
  68                         "%s = %s.a <= 0.0 ? vec4(0,0,0,0) : vec4(ceil(%s.%s / %s.a * 255.0) / 255.0, %s.a);",
  69                         tmpVar.c_str(), tmpVar.c_str(), tmpVar.c_str(), swiz, tmpVar.c_str(), tmpVar.c_str());
  70                     break;
  71                 case GrConfigConversionEffect::kDivByAlpha_RoundDown_PMConversion:
  72                     fsBuilder->codeAppendf(
  73                         "%s = %s.a <= 0.0 ? vec4(0,0,0,0) : vec4(floor(%s.%s / %s.a * 255.0) / 255.0, %s.a);",
  74                         tmpVar.c_str(), tmpVar.c_str(), tmpVar.c_str(), swiz, tmpVar.c_str(), tmpVar.c_str());
  75                     break;
  76                 default:
  77                     SkFAIL("Unknown conversion op.");
  78                     break;
  79             }
  80             fsBuilder->codeAppendf("%s = %s;", outputColor, tmpVar.c_str());
  81         }
  82         SkString modulate;
  83         GrGLSLMulVarBy4f(&modulate, 2, outputColor, inputColor);
  84         fsBuilder->codeAppend(modulate.c_str());
  85     }
  86
  87     static inline void GenKey(const GrEffect& effect, const GrGLCaps&,
  88                               GrEffectKeyBuilder* b) {
  89         const GrConfigConversionEffect& conv = effect.cast<GrConfigConversionEffect>();
  90         uint32_t key = (conv.swapsRedAndBlue() ? 0 : 1) | (conv.pmConversion() << 1);
  91         b->add32(key);
  92     }
  93
  94 private:
  95     bool                                    fSwapRedAndBlue;
  96     GrConfigConversionEffect::PMConversion  fPMConversion;
  97
  98     typedef GrGLEffect INHERITED;
  99
 100 };
 101
 102 ///////////////////////////////////////////////////////////////////////////////
 103
 104 GrConfigConversionEffect::GrConfigConversionEffect(GrTexture* texture,
 105                                                    bool swapRedAndBlue,
 106                                                    PMConversion pmConversion,
 107                                                    const SkMatrix& matrix)
 108     : GrSingleTextureEffect(texture, matrix)
 109     , fSwapRedAndBlue(swapRedAndBlue)
 110     , fPMConversion(pmConversion) {
 111     SkASSERT(kRGBA_8888_GrPixelConfig == texture->config() ||
 112              kBGRA_8888_GrPixelConfig == texture->config());
 113     // Why did we pollute our texture cache instead of using a GrSingleTextureEffect?
 114     SkASSERT(swapRedAndBlue || kNone_PMConversion != pmConversion);
 115 }
 116
 117 const GrBackendEffectFactory& GrConfigConversionEffect::getFactory() const {
 118     return GrTBackendEffectFactory<GrConfigConversionEffect>::getInstance();
 119 }
 120
 121 bool GrConfigConversionEffect::onIsEqual(const GrEffect& s) const {
 122     const GrConfigConversionEffect& other = s.cast<GrConfigConversionEffect>();
 123     return this->texture(0) == s.texture(0) &&
 124            other.fSwapRedAndBlue == fSwapRedAndBlue &&
 125            other.fPMConversion == fPMConversion;
 126 }
 127
 128 void GrConfigConversionEffect::getConstantColorComponents(GrColor* color,
 129                                                           uint32_t* validFlags) const {
 130     this->updateConstantColorComponentsForModulation(color, validFlags);
 131 }
 132
 133 ///////////////////////////////////////////////////////////////////////////////
 134
 135 GR_DEFINE_EFFECT_TEST(GrConfigConversionEffect);
 136
 137 GrEffect* GrConfigConversionEffect::TestCreate(SkRandom* random,
 138                                                GrContext*,
 139                                                const GrDrawTargetCaps&,
 140                                                GrTexture* textures[]) {
 141     PMConversion pmConv = static_cast<PMConversion>(random->nextULessThan(kPMConversionCnt));
 142     bool swapRB;
 143     if (kNone_PMConversion == pmConv) {
 144         swapRB = true;
 145     } else {
 146         swapRB = random->nextBool();
 147     }
 148     return SkNEW_ARGS(GrConfigConversionEffect,
 149                                       (textures[GrEffectUnitTest::kSkiaPMTextureIdx],
 150                                        swapRB,
 151                                        pmConv,
 152                                        GrEffectUnitTest::TestMatrix(random)));
 153 }
 154
 155 ///////////////////////////////////////////////////////////////////////////////
 156 void GrConfigConversionEffect::TestForPreservingPMConversions(GrContext* context,
 157                                                               PMConversion* pmToUPMRule,
 158                                                               PMConversion* upmToPMRule) {
 159     *pmToUPMRule = kNone_PMConversion;
 160     *upmToPMRule = kNone_PMConversion;
 161     SkAutoTMalloc<uint32_t> data(256 * 256 * 3);
 162     uint32_t* srcData = data.get();
 163     uint32_t* firstRead = data.get() + 256 * 256;
 164     uint32_t* secondRead = data.get() + 2 * 256 * 256;
 165
 166     // Fill with every possible premultiplied A, color channel value. There will be 256-y duplicate
 167     // values in row y. We set r,g, and b to the same value since they are handled identically.
 168     for (int y = 0; y < 256; ++y) {
 169         for (int x = 0; x < 256; ++x) {
 170             uint8_t* color = reinterpret_cast<uint8_t*>(&srcData[256*y + x]);
 171             color[3] = y;
 172             color[2] = SkTMin(x, y);
 173             color[1] = SkTMin(x, y);
 174             color[0] = SkTMin(x, y);
 175         }
 176     }
 177
 178     GrTextureDesc desc;
 179     desc.fFlags = kRenderTarget_GrTextureFlagBit |
 180                   kNoStencil_GrTextureFlagBit;
 181     desc.fWidth = 256;
 182     desc.fHeight = 256;
 183     desc.fConfig = kRGBA_8888_GrPixelConfig;
 184
 185     SkAutoTUnref<GrTexture> readTex(context->createUncachedTexture(desc, NULL, 0));
 186     if (!readTex.get()) {
 187         return;
 188     }
 189     SkAutoTUnref<GrTexture> tempTex(context->createUncachedTexture(desc, NULL, 0));
 190     if (!tempTex.get()) {
 191         return;
 192     }
 193     desc.fFlags = kNone_GrTextureFlags;
 194     SkAutoTUnref<GrTexture> dataTex(context->createUncachedTexture(desc, data, 0));
 195     if (!dataTex.get()) {
 196         return;
 197     }
 198
 199     static const PMConversion kConversionRules[][2] = {
 200         {kDivByAlpha_RoundDown_PMConversion, kMulByAlpha_RoundUp_PMConversion},
 201         {kDivByAlpha_RoundUp_PMConversion, kMulByAlpha_RoundDown_PMConversion},
 202     };
 203
 204     GrContext::AutoWideOpenIdentityDraw awoid(context, NULL);
 205
 206     bool failed = true;
 207
 208     for (size_t i = 0; i < SK_ARRAY_COUNT(kConversionRules) && failed; ++i) {
 209         *pmToUPMRule = kConversionRules[i][0];
 210         *upmToPMRule = kConversionRules[i][1];
 211
 212         static const SkRect kDstRect = SkRect::MakeWH(SkIntToScalar(256), SkIntToScalar(256));
 213         static const SkRect kSrcRect = SkRect::MakeWH(SK_Scalar1, SK_Scalar1);
 214         // We do a PM->UPM draw from dataTex to readTex and read the data. Then we do a UPM->PM draw
 215         // from readTex to tempTex followed by a PM->UPM draw to readTex and finally read the data.
 216         // We then verify that two reads produced the same values.
 217
 218         SkAutoTUnref<GrEffect> pmToUPM1(SkNEW_ARGS(GrConfigConversionEffect, (dataTex,
 219                                                                               false,
 220                                                                               *pmToUPMRule,
 221                                                                               SkMatrix::I())));
 222         SkAutoTUnref<GrEffect> upmToPM(SkNEW_ARGS(GrConfigConversionEffect, (readTex,
 223                                                                              false,
 224                                                                              *upmToPMRule,
 225                                                                              SkMatrix::I())));
 226         SkAutoTUnref<GrEffect> pmToUPM2(SkNEW_ARGS(GrConfigConversionEffect, (tempTex,
 227                                                                               false,
 228                                                                               *pmToUPMRule,
 229                                                                               SkMatrix::I())));
 230
 231         context->setRenderTarget(readTex->asRenderTarget());
 232         GrPaint paint1;
 233         paint1.addColorEffect(pmToUPM1);
 234         context->drawRectToRect(paint1, kDstRect, kSrcRect);
 235
 236         readTex->readPixels(0, 0, 256, 256, kRGBA_8888_GrPixelConfig, firstRead);
 237
 238         context->setRenderTarget(tempTex->asRenderTarget());
 239         GrPaint paint2;
 240         paint2.addColorEffect(upmToPM);
 241         context->drawRectToRect(paint2, kDstRect, kSrcRect);
 242         context->setRenderTarget(readTex->asRenderTarget());
 243
 244         GrPaint paint3;
 245         paint3.addColorEffect(pmToUPM2);
 246         context->drawRectToRect(paint3, kDstRect, kSrcRect);
 247
 248         readTex->readPixels(0, 0, 256, 256, kRGBA_8888_GrPixelConfig, secondRead);
 249
 250         failed = false;
 251         for (int y = 0; y < 256 && !failed; ++y) {
 252             for (int x = 0; x <= y; ++x) {
 253                 if (firstRead[256 * y + x] != secondRead[256 * y + x]) {
 254                     failed = true;
 255                     break;
 256                 }
 257             }
 258         }
 259     }
 260     if (failed) {
 261         *pmToUPMRule = kNone_PMConversion;
 262         *upmToPMRule = kNone_PMConversion;
 263     }
 264 }
 265
 266 const GrEffect* GrConfigConversionEffect::Create(GrTexture* texture,
 267                                                  bool swapRedAndBlue,
 268                                                  PMConversion pmConversion,
 269                                                  const SkMatrix& matrix) {
 270     if (!swapRedAndBlue && kNone_PMConversion == pmConversion) {
 271         // If we returned a GrConfigConversionEffect that was equivalent to a GrSimpleTextureEffect
 272         // then we may pollute our texture cache with redundant shaders. So in the case that no
 273         // conversions were requested we instead return a GrSimpleTextureEffect.
 274         return GrSimpleTextureEffect::Create(texture, matrix);
 275     } else {
 276         if (kRGBA_8888_GrPixelConfig != texture->config() &&
 277             kBGRA_8888_GrPixelConfig != texture->config() &&
 278             kNone_PMConversion != pmConversion) {
 279             // The PM conversions assume colors are 0..255
 280             return NULL;
 281         }
 282         return SkNEW_ARGS(GrConfigConversionEffect, (texture,
 283                                                      swapRedAndBlue,
 284                                                      pmConversion,
 285                                                      matrix));
 286     }
 287 }