GrConfigConversionEffect.cpp revision 2af1b188aa186936a78696e00170167204d9a666 
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 "gl/GrGLProgramStage.h"
10
11class GrGLConfigConversionEffect : public GrGLProgramStage {
12public:
13    GrGLConfigConversionEffect(const GrProgramStageFactory& factory,
14                               const GrCustomStage& s) : INHERITED (factory) {
15        const GrConfigConversionEffect& stage = static_cast<const GrConfigConversionEffect&>(s);
16        fSwapRedAndBlue = stage.swapsRedAndBlue();
17        fPMConversion = stage.pmConversion();
18    }
19
20    virtual void emitVS(GrGLShaderBuilder* builder,
21                        const char* vertexCoords) SK_OVERRIDE { }
22    virtual void emitFS(GrGLShaderBuilder* builder,
23                        const char* outputColor,
24                        const char* inputColor,
25                        const char* samplerName) SK_OVERRIDE {
26        builder->fFSCode.append("\tvec4 tempColor;\n");
27        builder->emitDefaultFetch("tempColor", samplerName);
28        if (GrConfigConversionEffect::kNone_PMConversion == fPMConversion) {
29            GrAssert(fSwapRedAndBlue);
30            builder->fFSCode.appendf("\t%s = tempColor.bgra;\n", outputColor);
31        } else {
32            const char* swiz = fSwapRedAndBlue ? "bgr" : "rgb";
33            switch (fPMConversion) {
34                case GrConfigConversionEffect::kMulByAlpha_RoundUp_PMConversion:
35                    builder->fFSCode.appendf(
36                        "\t%s = vec4(ceil(tempColor.%s*tempColor.a*255.0)/255.0, tempColor.a);\n",
37                         outputColor, swiz);
38                    break;
39                case GrConfigConversionEffect::kMulByAlpha_RoundDown_PMConversion:
40                    builder->fFSCode.appendf(
41                        "\t%s = vec4(floor(tempColor.%s*tempColor.a*255.0)/255.0, tempColor.a);\n",
42                         outputColor, swiz);
43                    break;
44                case GrConfigConversionEffect::kDivByAlpha_RoundUp_PMConversion:
45                    builder->fFSCode.appendf("\t%s = tempColor.a <= 0.0 ? vec4(0,0,0,0) : vec4(ceil(tempColor.%s / tempColor.a * 255.0)/255.0, tempColor.a);\n",
46                        outputColor, swiz);
47                    break;
48                case GrConfigConversionEffect::kDivByAlpha_RoundDown_PMConversion:
49                    builder->fFSCode.appendf("\t%s = tempColor.a <= 0.0 ? vec4(0,0,0,0) : vec4(floor(tempColor.%s / tempColor.a * 255.0)/255.0, tempColor.a);\n",
50                        outputColor, swiz);
51                    break;
52                default:
53                    GrCrash("Unknown conversion op.");
54                    break;
55            }
56        }
57    }
58
59    static inline StageKey GenKey(const GrCustomStage& s, const GrGLCaps&) {
60        const GrConfigConversionEffect& stage = static_cast<const GrConfigConversionEffect&>(s);
61        return static_cast<int>(stage.swapsRedAndBlue()) | (stage.pmConversion() << 1);
62    }
63
64private:
65    bool                                    fSwapRedAndBlue;
66    GrConfigConversionEffect::PMConversion  fPMConversion;
67
68    typedef GrGLProgramStage INHERITED;
69
70};
71
72///////////////////////////////////////////////////////////////////////////////
73
74GrConfigConversionEffect::GrConfigConversionEffect(GrTexture* texture,
75                                                   bool swapRedAndBlue,
76                                                   PMConversion pmConversion)
77    : GrSingleTextureEffect(texture)
78    , fSwapRedAndBlue(swapRedAndBlue)
79    , fPMConversion(pmConversion) {
80    GrAssert(kRGBA_8888_GrPixelConfig == texture->config() ||
81             kBGRA_8888_GrPixelConfig == texture->config());
82    // Why did we pollute our texture cache instead of using a GrSingleTextureEffect?
83    GrAssert(swapRedAndBlue || kNone_PMConversion != pmConversion);
84}
85
86const GrProgramStageFactory& GrConfigConversionEffect::getFactory() const {
87    return GrTProgramStageFactory<GrConfigConversionEffect>::getInstance();
88}
89
90bool GrConfigConversionEffect::isEqual(const GrCustomStage& s) const {
91    const GrConfigConversionEffect& other = static_cast<const GrConfigConversionEffect&>(s);
92    return other.fSwapRedAndBlue == fSwapRedAndBlue && other.fPMConversion == fPMConversion;
93}
94
95///////////////////////////////////////////////////////////////////////////////
96
97GR_DEFINE_CUSTOM_STAGE_TEST(GrConfigConversionEffect);
98
99GrCustomStage* GrConfigConversionEffect::TestCreate(SkRandom* random,
100                                                    GrContext* context,
101                                                    GrTexture* textures[]) {
102    PMConversion pmConv = static_cast<PMConversion>(random->nextULessThan(kPMConversionCnt));
103    bool swapRB;
104    if (kNone_PMConversion == pmConv) {
105        swapRB = true;
106    } else {
107        swapRB = random->nextBool();
108    }
109    return SkNEW_ARGS(GrConfigConversionEffect,
110            (textures[GrCustomStageUnitTest::kSkiaPMTextureIdx], swapRB, pmConv));
111}
112
113///////////////////////////////////////////////////////////////////////////////
114void GrConfigConversionEffect::TestForPreservingPMConversions(GrContext* context,
115                                                              PMConversion* pmToUPMRule,
116                                                              PMConversion* upmToPMRule) {
117    *pmToUPMRule = kNone_PMConversion;
118    *upmToPMRule = kNone_PMConversion;
119    SkAutoTMalloc<uint32_t> data(256 * 256 * 3);
120    uint32_t* srcData = data.get();
121    uint32_t* firstRead = data.get() + 256 * 256;
122    uint32_t* secondRead = data.get() + 2 * 256 * 256;
123
124    // Fill with every possible premultiplied A, color channel value. There will be 256-y duplicate
125    // values in row y. We set r,g, and b to the same value since they are handled identically.
126    for (int y = 0; y < 256; ++y) {
127        for (int x = 0; x < 256; ++x) {
128            uint8_t* color = reinterpret_cast<uint8_t*>(&srcData[256*y + x]);
129            color[3] = y;
130            color[2] = GrMin(x, y);
131            color[1] = GrMin(x, y);
132            color[0] = GrMin(x, y);
133        }
134    }
135
136    GrTextureDesc desc;
137    desc.fFlags = kRenderTarget_GrTextureFlagBit |
138                  kNoStencil_GrTextureFlagBit;
139    desc.fWidth = 256;
140    desc.fHeight = 256;
141    desc.fConfig = kRGBA_8888_GrPixelConfig;
142
143    SkAutoTUnref<GrTexture> readTex(context->createUncachedTexture(desc, NULL, 0));
144    if (!readTex.get()) {
145        return;
146    }
147    SkAutoTUnref<GrTexture> tempTex(context->createUncachedTexture(desc, NULL, 0));
148    if (!tempTex.get()) {
149        return;
150    }
151    desc.fFlags = kNone_GrTextureFlags;
152    SkAutoTUnref<GrTexture> dataTex(context->createUncachedTexture(desc, data, 0));
153    if (!dataTex.get()) {
154        return;
155    }
156
157    static const PMConversion kConversionRules[][2] = {
158        {kDivByAlpha_RoundDown_PMConversion, kMulByAlpha_RoundUp_PMConversion},
159        {kDivByAlpha_RoundUp_PMConversion, kMulByAlpha_RoundDown_PMConversion},
160    };
161
162    GrContext::AutoWideOpenIdentityDraw awoid(context, NULL);
163
164    bool failed = true;
165
166    for (size_t i = 0; i < GR_ARRAY_COUNT(kConversionRules) && failed; ++i) {
167        *pmToUPMRule = kConversionRules[i][0];
168        *upmToPMRule = kConversionRules[i][1];
169
170        static const GrRect kDstRect = GrRect::MakeWH(GrIntToScalar(256), GrIntToScalar(256));
171        static const GrRect kSrcRect = GrRect::MakeWH(GR_Scalar1, GR_Scalar1);
172        // We do a PM->UPM draw from dataTex to readTex and read the data. Then we do a UPM->PM draw
173        // from readTex to tempTex followed by a PM->UPM draw to readTex and finally read the data.
174        // We then verify that two reads produced the same values.
175
176        GrPaint paint;
177        paint.reset();
178
179        SkAutoTUnref<GrCustomStage> pmToUPMStage1(SkNEW_ARGS(GrConfigConversionEffect,
180                                                             (dataTex, false, *pmToUPMRule)));
181        SkAutoTUnref<GrCustomStage> upmToPMStage(SkNEW_ARGS(GrConfigConversionEffect,
182                                                            (readTex, false, *upmToPMRule)));
183        SkAutoTUnref<GrCustomStage> pmToUPMStage2(SkNEW_ARGS(GrConfigConversionEffect,
184                                                             (tempTex, false, *pmToUPMRule)));
185
186        context->setRenderTarget(readTex->asRenderTarget());
187        paint.textureSampler(0)->setCustomStage(pmToUPMStage1);
188        context->drawRectToRect(paint, kDstRect, kSrcRect);
189
190        readTex->readPixels(0, 0, 256, 256, kRGBA_8888_GrPixelConfig, firstRead);
191
192        context->setRenderTarget(tempTex->asRenderTarget());
193        paint.textureSampler(0)->setCustomStage(upmToPMStage);
194        context->drawRectToRect(paint, kDstRect, kSrcRect);
195        context->setRenderTarget(readTex->asRenderTarget());
196        paint.textureSampler(0)->setCustomStage(pmToUPMStage2);
197        context->drawRectToRect(paint, kDstRect, kSrcRect);
198
199        readTex->readPixels(0, 0, 256, 256, kRGBA_8888_GrPixelConfig, secondRead);
200
201        failed = false;
202        for (int y = 0; y < 256 && !failed; ++y) {
203            for (int x = 0; x <= y; ++x) {
204                if (firstRead[256 * y + x] != secondRead[256 * y + x]) {
205                    failed = true;
206                    break;
207                }
208            }
209        }
210    }
211    if (failed) {
212        *pmToUPMRule = kNone_PMConversion;
213        *upmToPMRule = kNone_PMConversion;
214    }
215}
216
217GrCustomStage* GrConfigConversionEffect::Create(GrTexture* texture,
218                                                bool swapRedAndBlue,
219                                                PMConversion pmConversion) {
220    if (!swapRedAndBlue && kNone_PMConversion == pmConversion) {
221        // If we returned a GrConfigConversionEffect that was equivalent to a GrSingleTextureEffect
222        // then we may pollute our texture cache with redundant shaders. So in the case that no
223        // conversions were requested we instead return a GrSingleTextureEffect.
224        return SkNEW_ARGS(GrSingleTextureEffect, (texture));
225    } else {
226        if (kRGBA_8888_GrPixelConfig != texture->config() &&
227            kBGRA_8888_GrPixelConfig != texture->config() &&
228            kNone_PMConversion != pmConversion) {
229            // The PM conversions assume colors are 0..255
230            return NULL;
231        }
232        return SkNEW_ARGS(GrConfigConversionEffect, (texture, swapRedAndBlue, pmConversion));
233    }
234}
235