GrConfigConversionEffect.cpp revision 586d5d640b19860dfbbd903a5188da1bbbe87336 
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 "GrInvariantOutput.h"
11#include "GrSimpleTextureEffect.h"
12#include "SkMatrix.h"
13#include "gl/GrGLProcessor.h"
14#include "gl/builders/GrGLProgramBuilder.h"
15
16class GrGLConfigConversionEffect : public GrGLFragmentProcessor {
17public:
18    GrGLConfigConversionEffect(const GrProcessor& processor) {
19        const GrConfigConversionEffect& configConversionEffect =
20                processor.cast<GrConfigConversionEffect>();
21        fSwapRedAndBlue = configConversionEffect.swapsRedAndBlue();
22        fPMConversion = configConversionEffect.pmConversion();
23    }
24
25    virtual void emitCode(GrGLFPBuilder* builder,
26                          const GrFragmentProcessor&,
27                          const char* outputColor,
28                          const char* inputColor,
29                          const TransformedCoordsArray& coords,
30                          const TextureSamplerArray& samplers) SK_OVERRIDE {
31        // Using highp for GLES here in order to avoid some precision issues on specific GPUs.
32        GrGLShaderVar tmpVar("tmpColor", kVec4f_GrSLType, 0, kHigh_GrSLPrecision);
33        SkString tmpDecl;
34        tmpVar.appendDecl(builder->ctxInfo(), &tmpDecl);
35
36        GrGLFPFragmentBuilder* fsBuilder = builder->getFragmentShaderBuilder();
37
38        fsBuilder->codeAppendf("%s;", tmpDecl.c_str());
39
40        fsBuilder->codeAppendf("%s = ", tmpVar.c_str());
41        fsBuilder->appendTextureLookup(samplers[0], coords[0].c_str(), coords[0].getType());
42        fsBuilder->codeAppend(";");
43
44        if (GrConfigConversionEffect::kNone_PMConversion == fPMConversion) {
45            SkASSERT(fSwapRedAndBlue);
46            fsBuilder->codeAppendf("%s = %s.bgra;", outputColor, tmpVar.c_str());
47        } else {
48            const char* swiz = fSwapRedAndBlue ? "bgr" : "rgb";
49            switch (fPMConversion) {
50                case GrConfigConversionEffect::kMulByAlpha_RoundUp_PMConversion:
51                    fsBuilder->codeAppendf(
52                        "%s = vec4(ceil(%s.%s * %s.a * 255.0) / 255.0, %s.a);",
53                        tmpVar.c_str(), tmpVar.c_str(), swiz, tmpVar.c_str(), tmpVar.c_str());
54                    break;
55                case GrConfigConversionEffect::kMulByAlpha_RoundDown_PMConversion:
56                    // Add a compensation(0.001) here to avoid the side effect of the floor operation.
57                    // In Intel GPUs, the integer value converted from floor(%s.r * 255.0) / 255.0
58                    // is less than the integer value converted from  %s.r by 1 when the %s.r is
59                    // converted from the integer value 2^n, such as 1, 2, 4, 8, etc.
60                    fsBuilder->codeAppendf(
61                        "%s = vec4(floor(%s.%s * %s.a * 255.0 + 0.001) / 255.0, %s.a);",
62                        tmpVar.c_str(), tmpVar.c_str(), swiz, tmpVar.c_str(), tmpVar.c_str());
63                    break;
64                case GrConfigConversionEffect::kDivByAlpha_RoundUp_PMConversion:
65                    fsBuilder->codeAppendf(
66                        "%s = %s.a <= 0.0 ? vec4(0,0,0,0) : vec4(ceil(%s.%s / %s.a * 255.0) / 255.0, %s.a);",
67                        tmpVar.c_str(), tmpVar.c_str(), tmpVar.c_str(), swiz, tmpVar.c_str(), tmpVar.c_str());
68                    break;
69                case GrConfigConversionEffect::kDivByAlpha_RoundDown_PMConversion:
70                    fsBuilder->codeAppendf(
71                        "%s = %s.a <= 0.0 ? vec4(0,0,0,0) : vec4(floor(%s.%s / %s.a * 255.0) / 255.0, %s.a);",
72                        tmpVar.c_str(), tmpVar.c_str(), tmpVar.c_str(), swiz, tmpVar.c_str(), tmpVar.c_str());
73                    break;
74                default:
75                    SkFAIL("Unknown conversion op.");
76                    break;
77            }
78            fsBuilder->codeAppendf("%s = %s;", outputColor, tmpVar.c_str());
79        }
80        SkString modulate;
81        GrGLSLMulVarBy4f(&modulate, outputColor, inputColor);
82        fsBuilder->codeAppend(modulate.c_str());
83    }
84
85    static inline void GenKey(const GrProcessor& processor, const GrGLCaps&,
86                              GrProcessorKeyBuilder* b) {
87        const GrConfigConversionEffect& conv = processor.cast<GrConfigConversionEffect>();
88        uint32_t key = (conv.swapsRedAndBlue() ? 0 : 1) | (conv.pmConversion() << 1);
89        b->add32(key);
90    }
91
92private:
93    bool                                    fSwapRedAndBlue;
94    GrConfigConversionEffect::PMConversion  fPMConversion;
95
96    typedef GrGLFragmentProcessor INHERITED;
97
98};
99
100///////////////////////////////////////////////////////////////////////////////
101
102GrConfigConversionEffect::GrConfigConversionEffect(GrTexture* texture,
103                                                   bool swapRedAndBlue,
104                                                   PMConversion pmConversion,
105                                                   const SkMatrix& matrix)
106    : GrSingleTextureEffect(texture, matrix)
107    , fSwapRedAndBlue(swapRedAndBlue)
108    , fPMConversion(pmConversion) {
109    this->initClassID<GrConfigConversionEffect>();
110    SkASSERT(kRGBA_8888_GrPixelConfig == texture->config() ||
111             kBGRA_8888_GrPixelConfig == texture->config());
112    // Why did we pollute our texture cache instead of using a GrSingleTextureEffect?
113    SkASSERT(swapRedAndBlue || kNone_PMConversion != pmConversion);
114}
115
116bool GrConfigConversionEffect::onIsEqual(const GrFragmentProcessor& s) const {
117    const GrConfigConversionEffect& other = s.cast<GrConfigConversionEffect>();
118    return other.fSwapRedAndBlue == fSwapRedAndBlue &&
119           other.fPMConversion == fPMConversion;
120}
121
122void GrConfigConversionEffect::onComputeInvariantOutput(GrInvariantOutput* inout) const {
123    this->updateInvariantOutputForModulation(inout);
124}
125
126///////////////////////////////////////////////////////////////////////////////
127
128GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrConfigConversionEffect);
129
130GrFragmentProcessor* GrConfigConversionEffect::TestCreate(SkRandom* random,
131                                                          GrContext*,
132                                                          const GrDrawTargetCaps&,
133                                                          GrTexture* textures[]) {
134    PMConversion pmConv = static_cast<PMConversion>(random->nextULessThan(kPMConversionCnt));
135    bool swapRB;
136    if (kNone_PMConversion == pmConv) {
137        swapRB = true;
138    } else {
139        swapRB = random->nextBool();
140    }
141    return SkNEW_ARGS(GrConfigConversionEffect,
142                                      (textures[GrProcessorUnitTest::kSkiaPMTextureIdx],
143                                       swapRB,
144                                       pmConv,
145                                       GrProcessorUnitTest::TestMatrix(random)));
146}
147
148///////////////////////////////////////////////////////////////////////////////
149
150void GrConfigConversionEffect::getGLProcessorKey(const GrGLCaps& caps,
151                                                 GrProcessorKeyBuilder* b) const {
152    GrGLConfigConversionEffect::GenKey(*this, caps, b);
153}
154
155GrGLFragmentProcessor* GrConfigConversionEffect::createGLInstance() const {
156    return SkNEW_ARGS(GrGLConfigConversionEffect, (*this));
157}
158
159
160
161void GrConfigConversionEffect::TestForPreservingPMConversions(GrContext* context,
162                                                              PMConversion* pmToUPMRule,
163                                                              PMConversion* upmToPMRule) {
164    *pmToUPMRule = kNone_PMConversion;
165    *upmToPMRule = kNone_PMConversion;
166    SkAutoTMalloc<uint32_t> data(256 * 256 * 3);
167    uint32_t* srcData = data.get();
168    uint32_t* firstRead = data.get() + 256 * 256;
169    uint32_t* secondRead = data.get() + 2 * 256 * 256;
170
171    // Fill with every possible premultiplied A, color channel value. There will be 256-y duplicate
172    // values in row y. We set r,g, and b to the same value since they are handled identically.
173    for (int y = 0; y < 256; ++y) {
174        for (int x = 0; x < 256; ++x) {
175            uint8_t* color = reinterpret_cast<uint8_t*>(&srcData[256*y + x]);
176            color[3] = y;
177            color[2] = SkTMin(x, y);
178            color[1] = SkTMin(x, y);
179            color[0] = SkTMin(x, y);
180        }
181    }
182
183    GrSurfaceDesc desc;
184    desc.fFlags = kRenderTarget_GrSurfaceFlag;
185    desc.fWidth = 256;
186    desc.fHeight = 256;
187    desc.fConfig = kRGBA_8888_GrPixelConfig;
188
189    SkAutoTUnref<GrTexture> readTex(context->createTexture(desc, true, NULL, 0));
190    if (!readTex.get()) {
191        return;
192    }
193    SkAutoTUnref<GrTexture> tempTex(context->createTexture(desc, true, NULL, 0));
194    if (!tempTex.get()) {
195        return;
196    }
197    desc.fFlags = kNone_GrSurfaceFlags;
198    SkAutoTUnref<GrTexture> dataTex(context->createTexture(desc, true, data, 0));
199    if (!dataTex.get()) {
200        return;
201    }
202
203    static const PMConversion kConversionRules[][2] = {
204        {kDivByAlpha_RoundDown_PMConversion, kMulByAlpha_RoundUp_PMConversion},
205        {kDivByAlpha_RoundUp_PMConversion, kMulByAlpha_RoundDown_PMConversion},
206    };
207
208    bool failed = true;
209
210    for (size_t i = 0; i < SK_ARRAY_COUNT(kConversionRules) && failed; ++i) {
211        *pmToUPMRule = kConversionRules[i][0];
212        *upmToPMRule = kConversionRules[i][1];
213
214        static const SkRect kDstRect = SkRect::MakeWH(SkIntToScalar(256), SkIntToScalar(256));
215        static const SkRect kSrcRect = SkRect::MakeWH(SK_Scalar1, SK_Scalar1);
216        // We do a PM->UPM draw from dataTex to readTex and read the data. Then we do a UPM->PM draw
217        // from readTex to tempTex followed by a PM->UPM draw to readTex and finally read the data.
218        // We then verify that two reads produced the same values.
219
220        SkAutoTUnref<GrFragmentProcessor> pmToUPM1(
221                SkNEW_ARGS(GrConfigConversionEffect,
222                           (dataTex, false, *pmToUPMRule, SkMatrix::I())));
223        SkAutoTUnref<GrFragmentProcessor> upmToPM(
224                SkNEW_ARGS(GrConfigConversionEffect,
225                           (readTex, false, *upmToPMRule, SkMatrix::I())));
226        SkAutoTUnref<GrFragmentProcessor> pmToUPM2(
227                SkNEW_ARGS(GrConfigConversionEffect,
228                           (tempTex, false, *pmToUPMRule, SkMatrix::I())));
229
230        GrPaint paint1;
231        paint1.addColorProcessor(pmToUPM1);
232        context->drawNonAARectToRect(readTex->asRenderTarget(),
233                                     GrClip::WideOpen(),
234                                     paint1,
235                                     SkMatrix::I(),
236                                     kDstRect,
237                                     kSrcRect);
238
239        readTex->readPixels(0, 0, 256, 256, kRGBA_8888_GrPixelConfig, firstRead);
240
241        GrPaint paint2;
242        paint2.addColorProcessor(upmToPM);
243        context->drawNonAARectToRect(tempTex->asRenderTarget(),
244                                     GrClip::WideOpen(),
245                                     paint2,
246                                     SkMatrix::I(),
247                                     kDstRect,
248                                     kSrcRect);
249
250        GrPaint paint3;
251        paint3.addColorProcessor(pmToUPM2);
252        context->drawNonAARectToRect(readTex->asRenderTarget(),
253                                     GrClip::WideOpen(),
254                                     paint3,
255                                     SkMatrix::I(),
256                                     kDstRect,
257                                     kSrcRect);
258
259        readTex->readPixels(0, 0, 256, 256, kRGBA_8888_GrPixelConfig, secondRead);
260
261        failed = false;
262        for (int y = 0; y < 256 && !failed; ++y) {
263            for (int x = 0; x <= y; ++x) {
264                if (firstRead[256 * y + x] != secondRead[256 * y + x]) {
265                    failed = true;
266                    break;
267                }
268            }
269        }
270    }
271    if (failed) {
272        *pmToUPMRule = kNone_PMConversion;
273        *upmToPMRule = kNone_PMConversion;
274    }
275}
276
277const GrFragmentProcessor* GrConfigConversionEffect::Create(GrTexture* texture,
278                                                 bool swapRedAndBlue,
279                                                 PMConversion pmConversion,
280                                                 const SkMatrix& matrix) {
281    if (!swapRedAndBlue && kNone_PMConversion == pmConversion) {
282        // If we returned a GrConfigConversionEffect that was equivalent to a GrSimpleTextureEffect
283        // then we may pollute our texture cache with redundant shaders. So in the case that no
284        // conversions were requested we instead return a GrSimpleTextureEffect.
285        return GrSimpleTextureEffect::Create(texture, matrix);
286    } else {
287        if (kRGBA_8888_GrPixelConfig != texture->config() &&
288            kBGRA_8888_GrPixelConfig != texture->config() &&
289            kNone_PMConversion != pmConversion) {
290            // The PM conversions assume colors are 0..255
291            return NULL;
292        }
293        return SkNEW_ARGS(GrConfigConversionEffect, (texture,
294                                                     swapRedAndBlue,
295                                                     pmConversion,
296                                                     matrix));
297    }
298}
299