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
15class GrGLConfigConversionEffect : public GrGLEffect {
16public:
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
78private:
79    bool                                    fSwapRedAndBlue;
80    GrConfigConversionEffect::PMConversion  fPMConversion;
81
82    typedef GrGLEffect INHERITED;
83
84};
85
86///////////////////////////////////////////////////////////////////////////////
87
88GrConfigConversionEffect::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
101const GrBackendEffectFactory& GrConfigConversionEffect::getFactory() const {
102    return GrTBackendEffectFactory<GrConfigConversionEffect>::getInstance();
103}
104
105bool 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
112void GrConfigConversionEffect::getConstantColorComponents(GrColor* color,
113                                                          uint32_t* validFlags) const {
114    this->updateConstantColorComponentsForModulation(color, validFlags);
115}
116
117///////////////////////////////////////////////////////////////////////////////
118
119GR_DEFINE_EFFECT_TEST(GrConfigConversionEffect);
120
121GrEffectRef* 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    AutoEffectUnref effect(SkNEW_ARGS(GrConfigConversionEffect,
133                                      (textures[GrEffectUnitTest::kSkiaPMTextureIdx],
134                                       swapRB,
135                                       pmConv,
136                                       GrEffectUnitTest::TestMatrix(random))));
137    return CreateEffectRef(effect);
138}
139
140///////////////////////////////////////////////////////////////////////////////
141void 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        AutoEffectUnref pmToUPM1(SkNEW_ARGS(GrConfigConversionEffect, (dataTex,
204                                                                       false,
205                                                                       *pmToUPMRule,
206                                                                       SkMatrix::I())));
207        AutoEffectUnref upmToPM(SkNEW_ARGS(GrConfigConversionEffect, (readTex,
208                                                                      false,
209                                                                      *upmToPMRule,
210                                                                      SkMatrix::I())));
211        AutoEffectUnref pmToUPM2(SkNEW_ARGS(GrConfigConversionEffect, (tempTex,
212                                                                       false,
213                                                                       *pmToUPMRule,
214                                                                       SkMatrix::I())));
215
216        SkAutoTUnref<GrEffectRef> pmToUPMEffect1(CreateEffectRef(pmToUPM1));
217        SkAutoTUnref<GrEffectRef> upmToPMEffect(CreateEffectRef(upmToPM));
218        SkAutoTUnref<GrEffectRef> pmToUPMEffect2(CreateEffectRef(pmToUPM2));
219
220        context->setRenderTarget(readTex->asRenderTarget());
221        GrPaint paint1;
222        paint1.addColorEffect(pmToUPMEffect1);
223        context->drawRectToRect(paint1, kDstRect, kSrcRect);
224
225        readTex->readPixels(0, 0, 256, 256, kRGBA_8888_GrPixelConfig, firstRead);
226
227        context->setRenderTarget(tempTex->asRenderTarget());
228        GrPaint paint2;
229        paint2.addColorEffect(upmToPMEffect);
230        context->drawRectToRect(paint2, kDstRect, kSrcRect);
231        context->setRenderTarget(readTex->asRenderTarget());
232
233        GrPaint paint3;
234        paint3.addColorEffect(pmToUPMEffect2);
235        context->drawRectToRect(paint3, kDstRect, kSrcRect);
236
237        readTex->readPixels(0, 0, 256, 256, kRGBA_8888_GrPixelConfig, secondRead);
238
239        failed = false;
240        for (int y = 0; y < 256 && !failed; ++y) {
241            for (int x = 0; x <= y; ++x) {
242                if (firstRead[256 * y + x] != secondRead[256 * y + x]) {
243                    failed = true;
244                    break;
245                }
246            }
247        }
248    }
249    if (failed) {
250        *pmToUPMRule = kNone_PMConversion;
251        *upmToPMRule = kNone_PMConversion;
252    }
253}
254
255const GrEffectRef* GrConfigConversionEffect::Create(GrTexture* texture,
256                                                    bool swapRedAndBlue,
257                                                    PMConversion pmConversion,
258                                                    const SkMatrix& matrix) {
259    if (!swapRedAndBlue && kNone_PMConversion == pmConversion) {
260        // If we returned a GrConfigConversionEffect that was equivalent to a GrSimpleTextureEffect
261        // then we may pollute our texture cache with redundant shaders. So in the case that no
262        // conversions were requested we instead return a GrSimpleTextureEffect.
263        return GrSimpleTextureEffect::Create(texture, matrix);
264    } else {
265        if (kRGBA_8888_GrPixelConfig != texture->config() &&
266            kBGRA_8888_GrPixelConfig != texture->config() &&
267            kNone_PMConversion != pmConversion) {
268            // The PM conversions assume colors are 0..255
269            return NULL;
270        }
271        AutoEffectUnref effect(SkNEW_ARGS(GrConfigConversionEffect, (texture,
272                                                                     swapRedAndBlue,
273                                                                     pmConversion,
274                                                                     matrix)));
275        return CreateEffectRef(effect);
276    }
277}
278