Do premul and r/b swap conversions in a custom effect
Review URL: https://codereview.appspot.com/6473060/
git-svn-id: http://skia.googlecode.com/svn/trunk@5284 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/effects/GrConfigConversionEffect.cpp b/src/gpu/effects/GrConfigConversionEffect.cpp
new file mode 100644
index 0000000..972f07f
--- /dev/null
+++ b/src/gpu/effects/GrConfigConversionEffect.cpp
@@ -0,0 +1,231 @@
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "GrConfigConversionEffect.h"
+#include "gl/GrGLProgramStage.h"
+
+class GrGLConfigConversionEffect : public GrGLProgramStage {
+public:
+ GrGLConfigConversionEffect(const GrProgramStageFactory& factory,
+ const GrCustomStage& s) : INHERITED (factory) {
+ const GrConfigConversionEffect& stage = static_cast<const GrConfigConversionEffect&>(s);
+ fSwapRedAndBlue = stage.swapsRedAndBlue();
+ fPMConversion = stage.pmConversion();
+ }
+
+ virtual void emitVS(GrGLShaderBuilder* builder,
+ const char* vertexCoords) SK_OVERRIDE { }
+ virtual void emitFS(GrGLShaderBuilder* builder,
+ const char* outputColor,
+ const char* inputColor,
+ const char* samplerName) SK_OVERRIDE {
+ builder->fFSCode.append("\tvec4 tempColor;\n");
+ builder->emitDefaultFetch("tempColor", samplerName);
+ if (GrConfigConversionEffect::kNone_PMConversion == fPMConversion) {
+ GrAssert(fSwapRedAndBlue);
+ builder->fFSCode.appendf("\t%s = tempColor.bgra;\n", outputColor);
+ } else {
+ const char* swiz = fSwapRedAndBlue ? "bgr" : "rgb";
+ switch (fPMConversion) {
+ case GrConfigConversionEffect::kMulByAlpha_RoundUp_PMConversion:
+ builder->fFSCode.appendf(
+ "\t%s = vec4(ceil(tempColor.%s*tempColor.a*255.0)/255.0, tempColor.a);\n",
+ outputColor, swiz);
+ break;
+ case GrConfigConversionEffect::kMulByAlpha_RoundDown_PMConversion:
+ builder->fFSCode.appendf(
+ "\t%s = vec4(floor(tempColor.%s*tempColor.a*255.0)/255.0, tempColor.a);\n",
+ outputColor, swiz);
+ break;
+ case GrConfigConversionEffect::kDivByAlpha_RoundUp_PMConversion:
+ 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",
+ outputColor, swiz);
+ break;
+ case GrConfigConversionEffect::kDivByAlpha_RoundDown_PMConversion:
+ 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",
+ outputColor, swiz);
+ break;
+ }
+ }
+ }
+
+ static inline StageKey GenKey(const GrCustomStage& s, const GrGLCaps&) {
+ const GrConfigConversionEffect& stage = static_cast<const GrConfigConversionEffect&>(s);
+ return static_cast<int>(stage.swapsRedAndBlue()) | (stage.pmConversion() << 1);
+ }
+
+private:
+ bool fSwapRedAndBlue;
+ GrConfigConversionEffect::PMConversion fPMConversion;
+
+ typedef GrGLProgramStage INHERITED;
+
+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+GrConfigConversionEffect::GrConfigConversionEffect(GrTexture* texture,
+ bool swapRedAndBlue,
+ PMConversion pmConversion)
+ : GrSingleTextureEffect(texture)
+ , fSwapRedAndBlue(swapRedAndBlue)
+ , fPMConversion(pmConversion) {
+ GrAssert(kRGBA_8888_GrPixelConfig == texture->config() ||
+ kBGRA_8888_GrPixelConfig == texture->config());
+ // Why did we pollute our texture cache instead of using a GrSingleTextureEffect?
+ GrAssert(swapRedAndBlue || kNone_PMConversion != pmConversion);
+}
+
+const GrProgramStageFactory& GrConfigConversionEffect::getFactory() const {
+ return GrTProgramStageFactory<GrConfigConversionEffect>::getInstance();
+}
+
+bool GrConfigConversionEffect::isEqual(const GrCustomStage& s) const {
+ const GrConfigConversionEffect& other = static_cast<const GrConfigConversionEffect&>(s);
+ return other.fSwapRedAndBlue == fSwapRedAndBlue && other.fPMConversion == fPMConversion;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+GR_DEFINE_CUSTOM_STAGE_TEST(GrConfigConversionEffect);
+
+GrCustomStage* GrConfigConversionEffect::TestCreate(SkRandom* random,
+ GrContext* context,
+ GrTexture* textures[]) {
+ PMConversion pmConv = static_cast<PMConversion>(random->nextULessThan(kPMConversionCnt));
+ bool swapRB;
+ if (kNone_PMConversion == pmConv) {
+ swapRB = true;
+ } else {
+ swapRB = random->nextBool();
+ }
+ return SkNEW_ARGS(GrConfigConversionEffect,
+ (textures[GrCustomStageUnitTest::kSkiaPMTextureIdx], swapRB, pmConv));
+}
+
+///////////////////////////////////////////////////////////////////////////////
+void GrConfigConversionEffect::TestForPreservingPMConversions(GrContext* context,
+ PMConversion* pmToUPMRule,
+ PMConversion* upmToPMRule) {
+ *pmToUPMRule = kNone_PMConversion;
+ *upmToPMRule = kNone_PMConversion;
+ SkAutoTMalloc<uint32_t> data(256 * 256 * 3);
+ uint32_t* srcData = data.get();
+ uint32_t* firstRead = data.get() + 256 * 256;
+ uint32_t* secondRead = data.get() + 2 * 256 * 256;
+
+ // Fill with every possible premultiplied A, color channel value. There will be 256-y duplicate
+ // values in row y. We set r,g, and b to the same value since they are handled identically.
+ for (int y = 0; y < 256; ++y) {
+ for (int x = 0; x < 256; ++x) {
+ uint8_t* color = reinterpret_cast<uint8_t*>(&srcData[256*y + x]);
+ color[3] = y;
+ color[2] = GrMin(x, y);
+ color[1] = GrMin(x, y);
+ color[0] = GrMin(x, y);
+ }
+ }
+
+ GrTextureDesc desc;
+ desc.fFlags = kRenderTarget_GrTextureFlagBit |
+ kNoStencil_GrTextureFlagBit;
+ desc.fWidth = 256;
+ desc.fHeight = 256;
+ desc.fConfig = kRGBA_8888_GrPixelConfig;
+
+ SkAutoTUnref<GrTexture> readTex(context->createUncachedTexture(desc, NULL, 0));
+ if (!readTex.get()) {
+ return;
+ }
+ SkAutoTUnref<GrTexture> tempTex(context->createUncachedTexture(desc, NULL, 0));
+ if (!tempTex.get()) {
+ return;
+ }
+ desc.fFlags = kNone_GrTextureFlags;
+ SkAutoTUnref<GrTexture> dataTex(context->createUncachedTexture(desc, data, 0));
+ if (!dataTex.get()) {
+ return;
+ }
+
+ static const PMConversion kConversionRules[][2] = {
+ {kDivByAlpha_RoundDown_PMConversion, kMulByAlpha_RoundUp_PMConversion},
+ {kDivByAlpha_RoundUp_PMConversion, kMulByAlpha_RoundDown_PMConversion},
+ };
+
+ GrContext::AutoWideOpenIdentityDraw awoid(context, NULL);
+
+ bool failed = true;
+
+ for (size_t i = 0; i < GR_ARRAY_COUNT(kConversionRules) && failed; ++i) {
+ *pmToUPMRule = kConversionRules[i][0];
+ *upmToPMRule = kConversionRules[i][1];
+
+ static const GrRect kDstRect = GrRect::MakeWH(GrIntToScalar(256), GrIntToScalar(256));
+ static const GrRect kSrcRect = GrRect::MakeWH(GR_Scalar1, GR_Scalar1);
+ // We do a PM->UPM draw from dataTex to readTex and read the data. Then we do a UPM->PM draw
+ // from readTex to tempTex followed by a PM->UPM draw to readTex and finally read the data.
+ // We then verify that two reads produced the same values.
+
+ GrPaint paint;
+ paint.reset();
+
+ SkAutoTUnref<GrCustomStage> pmToUPMStage1(SkNEW_ARGS(GrConfigConversionEffect,
+ (dataTex, false, *pmToUPMRule)));
+ SkAutoTUnref<GrCustomStage> upmToPMStage(SkNEW_ARGS(GrConfigConversionEffect,
+ (readTex, false, *upmToPMRule)));
+ SkAutoTUnref<GrCustomStage> pmToUPMStage2(SkNEW_ARGS(GrConfigConversionEffect,
+ (tempTex, false, *pmToUPMRule)));
+
+ context->setRenderTarget(readTex->asRenderTarget());
+ paint.textureSampler(0)->setCustomStage(pmToUPMStage1);
+ context->drawRectToRect(paint, kDstRect, kSrcRect);
+
+ readTex->readPixels(0, 0, 256, 256, kRGBA_8888_GrPixelConfig, firstRead);
+
+ context->setRenderTarget(tempTex->asRenderTarget());
+ paint.textureSampler(0)->setCustomStage(upmToPMStage);
+ context->drawRectToRect(paint, kDstRect, kSrcRect);
+ context->setRenderTarget(readTex->asRenderTarget());
+ paint.textureSampler(0)->setCustomStage(pmToUPMStage2);
+ context->drawRectToRect(paint, kDstRect, kSrcRect);
+
+ readTex->readPixels(0, 0, 256, 256, kRGBA_8888_GrPixelConfig, secondRead);
+
+ failed = false;
+ for (int y = 0; y < 256 && !failed; ++y) {
+ for (int x = 0; x <= y; ++x) {
+ if (firstRead[256 * y + x] != secondRead[256 * y + x]) {
+ failed = true;
+ break;
+ }
+ }
+ }
+ }
+ if (failed) {
+ *pmToUPMRule = kNone_PMConversion;
+ *upmToPMRule = kNone_PMConversion;
+ }
+}
+
+GrCustomStage* GrConfigConversionEffect::Create(GrTexture* texture,
+ bool swapRedAndBlue,
+ PMConversion pmConversion) {
+ if (!swapRedAndBlue && kNone_PMConversion == pmConversion) {
+ // If we returned a GrConfigConversionEffect that was equivalent to a GrSingleTextureEffect
+ // then we may pollute our texture cache with redundant shaders. So in the case that no
+ // conversions were requested we instead return a GrSingleTextureEffect.
+ return SkNEW_ARGS(GrSingleTextureEffect, (texture));
+ } else {
+ if (kRGBA_8888_GrPixelConfig != texture->config() &&
+ kBGRA_8888_GrPixelConfig != texture->config() &&
+ kNone_PMConversion != pmConversion) {
+ // The PM conversions assume colors are 0..255
+ return NULL;
+ }
+ return SkNEW_ARGS(GrConfigConversionEffect, (texture, swapRedAndBlue, pmConversion));
+ }
+}