1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/src/gpu/effects/GrConfigConversionEffect.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,78 @@
1.4 +/*
1.5 + * Copyright 2012 Google Inc.
1.6 + *
1.7 + * Use of this source code is governed by a BSD-style license that can be
1.8 + * found in the LICENSE file.
1.9 + */
1.10 +
1.11 +#ifndef GrConfigConversionEffect_DEFINED
1.12 +#define GrConfigConversionEffect_DEFINED
1.13 +
1.14 +#include "GrSingleTextureEffect.h"
1.15 +
1.16 +class GrEffectStage;
1.17 +class GrGLConfigConversionEffect;
1.18 +
1.19 +/**
1.20 + * This class is used to perform config conversions. Clients may want to read/write data that is
1.21 + * unpremultiplied. Also on some systems reading/writing BGRA or RGBA is faster. In those cases we
1.22 + * read/write using the faster path and perform an R/B swap in the shader if the client data is in
1.23 + * the slower config.
1.24 + */
1.25 +class GrConfigConversionEffect : public GrSingleTextureEffect {
1.26 +public:
1.27 + /**
1.28 + * The PM->UPM or UPM->PM conversions to apply.
1.29 + */
1.30 + enum PMConversion {
1.31 + kNone_PMConversion = 0,
1.32 + kMulByAlpha_RoundUp_PMConversion,
1.33 + kMulByAlpha_RoundDown_PMConversion,
1.34 + kDivByAlpha_RoundUp_PMConversion,
1.35 + kDivByAlpha_RoundDown_PMConversion,
1.36 +
1.37 + kPMConversionCnt
1.38 + };
1.39 +
1.40 + // Installs an effect in the GrEffectStage to perform a config conversion.
1.41 + static const GrEffectRef* Create(GrTexture*,
1.42 + bool swapRedAndBlue,
1.43 + PMConversion pmConversion,
1.44 + const SkMatrix& matrix);
1.45 +
1.46 + static const char* Name() { return "Config Conversion"; }
1.47 + typedef GrGLConfigConversionEffect GLEffect;
1.48 +
1.49 + virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE;
1.50 +
1.51 + virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE;
1.52 +
1.53 + bool swapsRedAndBlue() const { return fSwapRedAndBlue; }
1.54 + PMConversion pmConversion() const { return fPMConversion; }
1.55 +
1.56 + // This function determines whether it is possible to choose PM->UPM and UPM->PM conversions
1.57 + // for which in any PM->UPM->PM->UPM sequence the two UPM values are the same. This means that
1.58 + // if pixels are read back to a UPM buffer, written back to PM to the GPU, and read back again
1.59 + // both reads will produce the same result. This test is quite expensive and should not be run
1.60 + // multiple times for a given context.
1.61 + static void TestForPreservingPMConversions(GrContext* context,
1.62 + PMConversion* PMToUPMRule,
1.63 + PMConversion* UPMToPMRule);
1.64 +
1.65 +private:
1.66 + GrConfigConversionEffect(GrTexture*,
1.67 + bool swapRedAndBlue,
1.68 + PMConversion pmConversion,
1.69 + const SkMatrix& matrix);
1.70 +
1.71 + virtual bool onIsEqual(const GrEffect&) const SK_OVERRIDE;
1.72 +
1.73 + bool fSwapRedAndBlue;
1.74 + PMConversion fPMConversion;
1.75 +
1.76 + GR_DECLARE_EFFECT_TEST;
1.77 +
1.78 + typedef GrSingleTextureEffect INHERITED;
1.79 +};
1.80 +
1.81 +#endif
