GrConfigConversionEffect.cpp revision f2703d83da3ab2ae18b45231fd4f11e16cce3184 
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 "GrTBackendProcessorFactory.h"
11#include "GrSimpleTextureEffect.h"
12#include "gl/GrGLProcessor.h"
13#include "gl/builders/GrGLProgramBuilder.h"
14#include "SkMatrix.h"
15
16class GrGLConfigConversionEffect : public GrGLFragmentProcessor {
17public:
18    GrGLConfigConversionEffect(const GrBackendProcessorFactory& factory,
19                               const GrProcessor& processor)
20    : INHERITED (factory) {
21        const GrConfigConversionEffect& configConversionEffect =
22                processor.cast<GrConfigConversionEffect>();
23        fSwapRedAndBlue = configConversionEffect.swapsRedAndBlue();
24        fPMConversion = configConversionEffect.pmConversion();
25    }
26
27    virtual void emitCode(GrGLFPBuilder* builder,
28                          const GrFragmentProcessor&,
29                          const GrProcessorKey& key,
30                          const char* outputColor,
31                          const char* inputColor,
32                          const TransformedCoordsArray& coords,
33                          const TextureSamplerArray& samplers) SK_OVERRIDE {
34        // Using highp for GLES here in order to avoid some precision issues on specific GPUs.
35        GrGLShaderVar tmpVar("tmpColor", kVec4f_GrSLType, 0, GrGLShaderVar::kHigh_Precision);
36        SkString tmpDecl;
37        tmpVar.appendDecl(builder->ctxInfo(), &tmpDecl);
38
39        GrGLFPFragmentBuilder* fsBuilder = builder->getFragmentShaderBuilder();
40
41        fsBuilder->codeAppendf("%s;", tmpDecl.c_str());
42
43        fsBuilder->codeAppendf("%s = ", tmpVar.c_str());
44        fsBuilder->appendTextureLookup(samplers[0], coords[0].c_str(), coords[0].getType());
45        fsBuilder->codeAppend(";");
46
47        if (GrConfigConversionEffect::kNone_PMConversion == fPMConversion) {
48            SkASSERT(fSwapRedAndBlue);
49            fsBuilder->codeAppendf("%s = %s.bgra;", outputColor, tmpVar.c_str());
50        } else {
51            const char* swiz = fSwapRedAndBlue ? "bgr" : "rgb";
52            switch (fPMConversion) {
53                case GrConfigConversionEffect::kMulByAlpha_RoundUp_PMConversion:
54                    fsBuilder->codeAppendf(
55                        "%s = vec4(ceil(%s.%s * %s.a * 255.0) / 255.0, %s.a);",
56                        tmpVar.c_str(), tmpVar.c_str(), swiz, tmpVar.c_str(), tmpVar.c_str());
57                    break;
58                case GrConfigConversionEffect::kMulByAlpha_RoundDown_PMConversion:
59                    // Add a compensation(0.001) here to avoid the side effect of the floor operation.
60                    // In Intel GPUs, the integer value converted from floor(%s.r * 255.0) / 255.0
61                    // is less than the integer value converted from  %s.r by 1 when the %s.r is
62                    // converted from the integer value 2^n, such as 1, 2, 4, 8, etc.
63                    fsBuilder->codeAppendf(
64                        "%s = vec4(floor(%s.%s * %s.a * 255.0 + 0.001) / 255.0, %s.a);",
65                        tmpVar.c_str(), tmpVar.c_str(), swiz, tmpVar.c_str(), tmpVar.c_str());
66                    break;
67                case GrConfigConversionEffect::kDivByAlpha_RoundUp_PMConversion:
68                    fsBuilder->codeAppendf(
69                        "%s = %s.a <= 0.0 ? vec4(0,0,0,0) : vec4(ceil(%s.%s / %s.a * 255.0) / 255.0, %s.a);",
70                        tmpVar.c_str(), tmpVar.c_str(), tmpVar.c_str(), swiz, tmpVar.c_str(), tmpVar.c_str());
71                    break;
72                case GrConfigConversionEffect::kDivByAlpha_RoundDown_PMConversion:
73                    fsBuilder->codeAppendf(
74                        "%s = %s.a <= 0.0 ? vec4(0,0,0,0) : vec4(floor(%s.%s / %s.a * 255.0) / 255.0, %s.a);",
75                        tmpVar.c_str(), tmpVar.c_str(), tmpVar.c_str(), swiz, tmpVar.c_str(), tmpVar.c_str());
76                    break;
77                default:
78                    SkFAIL("Unknown conversion op.");
79                    break;
80            }
81            fsBuilder->codeAppendf("%s = %s;", outputColor, tmpVar.c_str());
82        }
83        SkString modulate;
84        GrGLSLMulVarBy4f(&modulate, outputColor, inputColor);
85        fsBuilder->codeAppend(modulate.c_str());
86    }
87
88    static inline void GenKey(const GrProcessor& processor, const GrGLCaps&,
89                              GrProcessorKeyBuilder* b) {
90        const GrConfigConversionEffect& conv = processor.cast<GrConfigConversionEffect>();
91        uint32_t key = (conv.swapsRedAndBlue() ? 0 : 1) | (conv.pmConversion() << 1);
92        b->add32(key);
93    }
94
95private:
96    bool                                    fSwapRedAndBlue;
97    GrConfigConversionEffect::PMConversion  fPMConversion;
98
99    typedef GrGLFragmentProcessor INHERITED;
100
101};
102
103///////////////////////////////////////////////////////////////////////////////
104
105GrConfigConversionEffect::GrConfigConversionEffect(GrTexture* texture,
106                                                   bool swapRedAndBlue,
107                                                   PMConversion pmConversion,
108                                                   const SkMatrix& matrix)
109    : GrSingleTextureEffect(texture, matrix)
110    , fSwapRedAndBlue(swapRedAndBlue)
111    , fPMConversion(pmConversion) {
112    SkASSERT(kRGBA_8888_GrPixelConfig == texture->config() ||
113             kBGRA_8888_GrPixelConfig == texture->config());
114    // Why did we pollute our texture cache instead of using a GrSingleTextureEffect?
115    SkASSERT(swapRedAndBlue || kNone_PMConversion != pmConversion);
116}
117
118const GrBackendFragmentProcessorFactory& GrConfigConversionEffect::getFactory() const {
119    return GrTBackendFragmentProcessorFactory<GrConfigConversionEffect>::getInstance();
120}
121
122bool GrConfigConversionEffect::onIsEqual(const GrFragmentProcessor& s) const {
123    const GrConfigConversionEffect& other = s.cast<GrConfigConversionEffect>();
124    return other.fSwapRedAndBlue == fSwapRedAndBlue &&
125           other.fPMConversion == fPMConversion;
126}
127
128void GrConfigConversionEffect::onComputeInvariantOutput(InvariantOutput* inout) const {
129    this->updateInvariantOutputForModulation(inout);
130}
131
132///////////////////////////////////////////////////////////////////////////////
133
134GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrConfigConversionEffect);
135
136GrFragmentProcessor* GrConfigConversionEffect::TestCreate(SkRandom* random,
137                                                          GrContext*,
138                                                          const GrDrawTargetCaps&,
139                                                          GrTexture* textures[]) {
140    PMConversion pmConv = static_cast<PMConversion>(random->nextULessThan(kPMConversionCnt));
141    bool swapRB;
142    if (kNone_PMConversion == pmConv) {
143        swapRB = true;
144    } else {
145        swapRB = random->nextBool();
146    }
147    return SkNEW_ARGS(GrConfigConversionEffect,
148                                      (textures[GrProcessorUnitTest::kSkiaPMTextureIdx],
149                                       swapRB,
150                                       pmConv,
151                                       GrProcessorUnitTest::TestMatrix(random)));
152}
153
154///////////////////////////////////////////////////////////////////////////////
155void GrConfigConversionEffect::TestForPreservingPMConversions(GrContext* context,
156                                                              PMConversion* pmToUPMRule,
157                                                              PMConversion* upmToPMRule) {
158    *pmToUPMRule = kNone_PMConversion;
159    *upmToPMRule = kNone_PMConversion;
160    SkAutoTMalloc<uint32_t> data(256 * 256 * 3);
161    uint32_t* srcData = data.get();
162    uint32_t* firstRead = data.get() + 256 * 256;
163    uint32_t* secondRead = data.get() + 2 * 256 * 256;
164
165    // Fill with every possible premultiplied A, color channel value. There will be 256-y duplicate
166    // values in row y. We set r,g, and b to the same value since they are handled identically.
167    for (int y = 0; y < 256; ++y) {
168        for (int x = 0; x < 256; ++x) {
169            uint8_t* color = reinterpret_cast<uint8_t*>(&srcData[256*y + x]);
170            color[3] = y;
171            color[2] = SkTMin(x, y);
172            color[1] = SkTMin(x, y);
173            color[0] = SkTMin(x, y);
174        }
175    }
176
177    GrSurfaceDesc desc;
178    desc.fFlags = kRenderTarget_GrSurfaceFlag |
179                  kNoStencil_GrSurfaceFlag;
180    desc.fWidth = 256;
181    desc.fHeight = 256;
182    desc.fConfig = kRGBA_8888_GrPixelConfig;
183
184    SkAutoTUnref<GrTexture> readTex(context->createUncachedTexture(desc, NULL, 0));
185    if (!readTex.get()) {
186        return;
187    }
188    SkAutoTUnref<GrTexture> tempTex(context->createUncachedTexture(desc, NULL, 0));
189    if (!tempTex.get()) {
190        return;
191    }
192    desc.fFlags = kNone_GrSurfaceFlags;
193    SkAutoTUnref<GrTexture> dataTex(context->createUncachedTexture(desc, data, 0));
194    if (!dataTex.get()) {
195        return;
196    }
197
198    static const PMConversion kConversionRules[][2] = {
199        {kDivByAlpha_RoundDown_PMConversion, kMulByAlpha_RoundUp_PMConversion},
200        {kDivByAlpha_RoundUp_PMConversion, kMulByAlpha_RoundDown_PMConversion},
201    };
202
203    GrContext::AutoWideOpenIdentityDraw awoid(context, NULL);
204
205    bool failed = true;
206
207    for (size_t i = 0; i < SK_ARRAY_COUNT(kConversionRules) && failed; ++i) {
208        *pmToUPMRule = kConversionRules[i][0];
209        *upmToPMRule = kConversionRules[i][1];
210
211        static const SkRect kDstRect = SkRect::MakeWH(SkIntToScalar(256), SkIntToScalar(256));
212        static const SkRect kSrcRect = SkRect::MakeWH(SK_Scalar1, SK_Scalar1);
213        // We do a PM->UPM draw from dataTex to readTex and read the data. Then we do a UPM->PM draw
214        // from readTex to tempTex followed by a PM->UPM draw to readTex and finally read the data.
215        // We then verify that two reads produced the same values.
216
217        SkAutoTUnref<GrFragmentProcessor> pmToUPM1(
218                SkNEW_ARGS(GrConfigConversionEffect,
219                           (dataTex, false, *pmToUPMRule, SkMatrix::I())));
220        SkAutoTUnref<GrFragmentProcessor> upmToPM(
221                SkNEW_ARGS(GrConfigConversionEffect,
222                           (readTex, false, *upmToPMRule, SkMatrix::I())));
223        SkAutoTUnref<GrFragmentProcessor> pmToUPM2(
224                SkNEW_ARGS(GrConfigConversionEffect,
225                           (tempTex, false, *pmToUPMRule, SkMatrix::I())));
226
227        context->setRenderTarget(readTex->asRenderTarget());
228        GrPaint paint1;
229        paint1.addColorProcessor(pmToUPM1);
230        context->drawRectToRect(paint1, kDstRect, kSrcRect);
231
232        readTex->readPixels(0, 0, 256, 256, kRGBA_8888_GrPixelConfig, firstRead);
233
234        context->setRenderTarget(tempTex->asRenderTarget());
235        GrPaint paint2;
236        paint2.addColorProcessor(upmToPM);
237        context->drawRectToRect(paint2, kDstRect, kSrcRect);
238        context->setRenderTarget(readTex->asRenderTarget());
239
240        GrPaint paint3;
241        paint3.addColorProcessor(pmToUPM2);
242        context->drawRectToRect(paint3, kDstRect, kSrcRect);
243
244        readTex->readPixels(0, 0, 256, 256, kRGBA_8888_GrPixelConfig, secondRead);
245
246        failed = false;
247        for (int y = 0; y < 256 && !failed; ++y) {
248            for (int x = 0; x <= y; ++x) {
249                if (firstRead[256 * y + x] != secondRead[256 * y + x]) {
250                    failed = true;
251                    break;
252                }
253            }
254        }
255    }
256    if (failed) {
257        *pmToUPMRule = kNone_PMConversion;
258        *upmToPMRule = kNone_PMConversion;
259    }
260}
261
262const GrFragmentProcessor* GrConfigConversionEffect::Create(GrTexture* texture,
263                                                 bool swapRedAndBlue,
264                                                 PMConversion pmConversion,
265                                                 const SkMatrix& matrix) {
266    if (!swapRedAndBlue && kNone_PMConversion == pmConversion) {
267        // If we returned a GrConfigConversionEffect that was equivalent to a GrSimpleTextureEffect
268        // then we may pollute our texture cache with redundant shaders. So in the case that no
269        // conversions were requested we instead return a GrSimpleTextureEffect.
270        return GrSimpleTextureEffect::Create(texture, matrix);
271    } else {
272        if (kRGBA_8888_GrPixelConfig != texture->config() &&
273            kBGRA_8888_GrPixelConfig != texture->config() &&
274            kNone_PMConversion != pmConversion) {
275            // The PM conversions assume colors are 0..255
276            return NULL;
277        }
278        return SkNEW_ARGS(GrConfigConversionEffect, (texture,
279                                                     swapRedAndBlue,
280                                                     pmConversion,
281                                                     matrix));
282    }
283}
284