GrConfigConversionEffect.cpp revision c3a58f345de16c185db3a20578c7ddf52bc89d38 
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 "GrTBackendEffectFactory.h"
10#include "gl/GrGLEffect.h"
11
12class GrGLConfigConversionEffect : public GrGLEffect {
13public:
14    GrGLConfigConversionEffect(const GrBackendEffectFactory& factory,
15                               const GrEffect& s) : INHERITED (factory) {
16        const GrConfigConversionEffect& effect = static_cast<const GrConfigConversionEffect&>(s);
17        fSwapRedAndBlue = effect.swapsRedAndBlue();
18        fPMConversion = effect.pmConversion();
19    }
20
21    virtual void emitCode(GrGLShaderBuilder* builder,
22                          const GrEffectStage&,
23                          EffectKey,
24                          const char* vertexCoords,
25                          const char* outputColor,
26                          const char* inputColor,
27                          const TextureSamplerArray& samplers) SK_OVERRIDE {
28        builder->fFSCode.appendf("\t\t%s = ", outputColor);
29        builder->appendTextureLookup(&builder->fFSCode, samplers[0]);
30        builder->fFSCode.append(";\n");
31        if (GrConfigConversionEffect::kNone_PMConversion == fPMConversion) {
32            GrAssert(fSwapRedAndBlue);
33            builder->fFSCode.appendf("\t%s = %s.bgra;\n", outputColor, outputColor);
34        } else {
35            const char* swiz = fSwapRedAndBlue ? "bgr" : "rgb";
36            switch (fPMConversion) {
37                case GrConfigConversionEffect::kMulByAlpha_RoundUp_PMConversion:
38                    builder->fFSCode.appendf(
39                        "\t\t%s = vec4(ceil(%s.%s * %s.a * 255.0) / 255.0, %s.a);\n",
40                        outputColor, outputColor, swiz, outputColor, outputColor);
41                    break;
42                case GrConfigConversionEffect::kMulByAlpha_RoundDown_PMConversion:
43                    builder->fFSCode.appendf(
44                        "\t\t%s = vec4(floor(%s.%s * %s.a * 255.0) / 255.0, %s.a);\n",
45                        outputColor, outputColor, swiz, outputColor, outputColor);
46                    break;
47                case GrConfigConversionEffect::kDivByAlpha_RoundUp_PMConversion:
48                    builder->fFSCode.appendf("\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",
49                        outputColor, outputColor, outputColor, swiz, outputColor, outputColor);
50                    break;
51                case GrConfigConversionEffect::kDivByAlpha_RoundDown_PMConversion:
52                    builder->fFSCode.appendf("\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",
53                        outputColor, outputColor, outputColor, swiz, outputColor, outputColor);
54                    break;
55                default:
56                    GrCrash("Unknown conversion op.");
57                    break;
58            }
59        }
60        GrGLSLMulVarBy4f(&builder->fFSCode, 2, outputColor, inputColor);
61    }
62
63    static inline EffectKey GenKey(const GrEffectStage& s, const GrGLCaps&) {
64        const GrConfigConversionEffect& effect =
65            static_cast<const GrConfigConversionEffect&>(*s.getEffect());
66        return static_cast<int>(effect.swapsRedAndBlue()) | (effect.pmConversion() << 1);
67    }
68
69private:
70    bool                                    fSwapRedAndBlue;
71    GrConfigConversionEffect::PMConversion  fPMConversion;
72
73    typedef GrGLEffect INHERITED;
74
75};
76
77///////////////////////////////////////////////////////////////////////////////
78
79GrConfigConversionEffect::GrConfigConversionEffect(GrTexture* texture,
80                                                   bool swapRedAndBlue,
81                                                   PMConversion pmConversion)
82    : GrSingleTextureEffect(texture)
83    , fSwapRedAndBlue(swapRedAndBlue)
84    , fPMConversion(pmConversion) {
85    GrAssert(kRGBA_8888_GrPixelConfig == texture->config() ||
86             kBGRA_8888_GrPixelConfig == texture->config());
87    // Why did we pollute our texture cache instead of using a GrSingleTextureEffect?
88    GrAssert(swapRedAndBlue || kNone_PMConversion != pmConversion);
89}
90
91const GrBackendEffectFactory& GrConfigConversionEffect::getFactory() const {
92    return GrTBackendEffectFactory<GrConfigConversionEffect>::getInstance();
93}
94
95bool GrConfigConversionEffect::isEqual(const GrEffect& s) const {
96    const GrConfigConversionEffect& other = static_cast<const GrConfigConversionEffect&>(s);
97    return other.fSwapRedAndBlue == fSwapRedAndBlue && other.fPMConversion == fPMConversion;
98}
99
100///////////////////////////////////////////////////////////////////////////////
101
102GR_DEFINE_EFFECT_TEST(GrConfigConversionEffect);
103
104GrEffect* GrConfigConversionEffect::TestCreate(SkRandom* random,
105                                               GrContext* context,
106                                               GrTexture* textures[]) {
107    PMConversion pmConv = static_cast<PMConversion>(random->nextULessThan(kPMConversionCnt));
108    bool swapRB;
109    if (kNone_PMConversion == pmConv) {
110        swapRB = true;
111    } else {
112        swapRB = random->nextBool();
113    }
114    return SkNEW_ARGS(GrConfigConversionEffect,
115            (textures[GrEffectUnitTest::kSkiaPMTextureIdx], swapRB, pmConv));
116}
117
118///////////////////////////////////////////////////////////////////////////////
119void GrConfigConversionEffect::TestForPreservingPMConversions(GrContext* context,
120                                                              PMConversion* pmToUPMRule,
121                                                              PMConversion* upmToPMRule) {
122    *pmToUPMRule = kNone_PMConversion;
123    *upmToPMRule = kNone_PMConversion;
124    SkAutoTMalloc<uint32_t> data(256 * 256 * 3);
125    uint32_t* srcData = data.get();
126    uint32_t* firstRead = data.get() + 256 * 256;
127    uint32_t* secondRead = data.get() + 2 * 256 * 256;
128
129    // Fill with every possible premultiplied A, color channel value. There will be 256-y duplicate
130    // values in row y. We set r,g, and b to the same value since they are handled identically.
131    for (int y = 0; y < 256; ++y) {
132        for (int x = 0; x < 256; ++x) {
133            uint8_t* color = reinterpret_cast<uint8_t*>(&srcData[256*y + x]);
134            color[3] = y;
135            color[2] = GrMin(x, y);
136            color[1] = GrMin(x, y);
137            color[0] = GrMin(x, y);
138        }
139    }
140
141    GrTextureDesc desc;
142    desc.fFlags = kRenderTarget_GrTextureFlagBit |
143                  kNoStencil_GrTextureFlagBit;
144    desc.fWidth = 256;
145    desc.fHeight = 256;
146    desc.fConfig = kRGBA_8888_GrPixelConfig;
147
148    SkAutoTUnref<GrTexture> readTex(context->createUncachedTexture(desc, NULL, 0));
149    if (!readTex.get()) {
150        return;
151    }
152    SkAutoTUnref<GrTexture> tempTex(context->createUncachedTexture(desc, NULL, 0));
153    if (!tempTex.get()) {
154        return;
155    }
156    desc.fFlags = kNone_GrTextureFlags;
157    SkAutoTUnref<GrTexture> dataTex(context->createUncachedTexture(desc, data, 0));
158    if (!dataTex.get()) {
159        return;
160    }
161
162    static const PMConversion kConversionRules[][2] = {
163        {kDivByAlpha_RoundDown_PMConversion, kMulByAlpha_RoundUp_PMConversion},
164        {kDivByAlpha_RoundUp_PMConversion, kMulByAlpha_RoundDown_PMConversion},
165    };
166
167    GrContext::AutoWideOpenIdentityDraw awoid(context, NULL);
168
169    bool failed = true;
170
171    for (size_t i = 0; i < GR_ARRAY_COUNT(kConversionRules) && failed; ++i) {
172        *pmToUPMRule = kConversionRules[i][0];
173        *upmToPMRule = kConversionRules[i][1];
174
175        static const GrRect kDstRect = GrRect::MakeWH(GrIntToScalar(256), GrIntToScalar(256));
176        static const GrRect kSrcRect = GrRect::MakeWH(GR_Scalar1, GR_Scalar1);
177        // We do a PM->UPM draw from dataTex to readTex and read the data. Then we do a UPM->PM draw
178        // from readTex to tempTex followed by a PM->UPM draw to readTex and finally read the data.
179        // We then verify that two reads produced the same values.
180
181        GrPaint paint;
182
183        SkAutoTUnref<GrEffect> pmToUPMEffect1(SkNEW_ARGS(GrConfigConversionEffect,
184                                                        (dataTex, false, *pmToUPMRule)));
185        SkAutoTUnref<GrEffect> upmToPMEffect(SkNEW_ARGS(GrConfigConversionEffect,
186                                                       (readTex, false, *upmToPMRule)));
187        SkAutoTUnref<GrEffect> pmToUPMEffect2(SkNEW_ARGS(GrConfigConversionEffect,
188                                                        (tempTex, false, *pmToUPMRule)));
189
190        context->setRenderTarget(readTex->asRenderTarget());
191        paint.colorStage(0)->setEffect(pmToUPMEffect1);
192        context->drawRectToRect(paint, kDstRect, kSrcRect);
193
194        readTex->readPixels(0, 0, 256, 256, kRGBA_8888_GrPixelConfig, firstRead);
195
196        context->setRenderTarget(tempTex->asRenderTarget());
197        paint.colorStage(0)->setEffect(upmToPMEffect);
198        context->drawRectToRect(paint, kDstRect, kSrcRect);
199        context->setRenderTarget(readTex->asRenderTarget());
200        paint.colorStage(0)->setEffect(pmToUPMEffect2);
201        context->drawRectToRect(paint, kDstRect, kSrcRect);
202
203        readTex->readPixels(0, 0, 256, 256, kRGBA_8888_GrPixelConfig, secondRead);
204
205        failed = false;
206        for (int y = 0; y < 256 && !failed; ++y) {
207            for (int x = 0; x <= y; ++x) {
208                if (firstRead[256 * y + x] != secondRead[256 * y + x]) {
209                    failed = true;
210                    break;
211                }
212            }
213        }
214    }
215    if (failed) {
216        *pmToUPMRule = kNone_PMConversion;
217        *upmToPMRule = kNone_PMConversion;
218    }
219}
220
221bool GrConfigConversionEffect::InstallEffect(GrTexture* texture,
222                                             bool swapRedAndBlue,
223                                             PMConversion pmConversion,
224                                             const GrMatrix& matrix,
225                                             GrEffectStage* stage) {
226    if (!swapRedAndBlue && kNone_PMConversion == pmConversion) {
227        // If we returned a GrConfigConversionEffect that was equivalent to a GrSingleTextureEffect
228        // then we may pollute our texture cache with redundant shaders. So in the case that no
229        // conversions were requested we instead return a GrSingleTextureEffect.
230        stage->setEffect(SkNEW_ARGS(GrSingleTextureEffect, (texture, matrix)), matrix)->unref();
231        return true;
232    } else {
233        if (kRGBA_8888_GrPixelConfig != texture->config() &&
234            kBGRA_8888_GrPixelConfig != texture->config() &&
235            kNone_PMConversion != pmConversion) {
236            // The PM conversions assume colors are 0..255
237            return false;
238        }
239        stage->setEffect(SkNEW_ARGS(GrConfigConversionEffect, (texture,
240                                                               swapRedAndBlue,
241                                                               pmConversion)), matrix)->unref();
242        return true;
243    }
244}
245