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 #ifndef GrConfigConversionEffect_DEFINED 9 #define GrConfigConversionEffect_DEFINED 10 11 #include "GrSingleTextureEffect.h" 12 13 class GrInvariantOutput; 14 15 /** 16 * This class is used to perform config conversions. Clients may want to read/write data that is 17 * unpremultiplied. 18 */ 19 class GrConfigConversionEffect : public GrSingleTextureEffect { 20 public: 21 /** 22 * The PM->UPM or UPM->PM conversions to apply. 23 */ 24 enum PMConversion { 25 kMulByAlpha_RoundUp_PMConversion = 0, 26 kMulByAlpha_RoundDown_PMConversion, 27 kDivByAlpha_RoundUp_PMConversion, 28 kDivByAlpha_RoundDown_PMConversion, 29 30 kPMConversionCnt 31 }; 32 33 static sk_sp<GrFragmentProcessor> Make(GrTexture*, PMConversion, const SkMatrix&); 34 35 static sk_sp<GrFragmentProcessor> Make(GrResourceProvider*, sk_sp<GrTextureProxy>, 36 PMConversion, const SkMatrix&); 37 38 const char* name() const override { return "Config Conversion"; } 39 40 PMConversion pmConversion() const { return fPMConversion; } 41 42 // This function determines whether it is possible to choose PM->UPM and UPM->PM conversions 43 // for which in any PM->UPM->PM->UPM sequence the two UPM values are the same. This means that 44 // if pixels are read back to a UPM buffer, written back to PM to the GPU, and read back again 45 // both reads will produce the same result. This test is quite expensive and should not be run 46 // multiple times for a given context. 47 static void TestForPreservingPMConversions(GrContext* context, 48 PMConversion* PMToUPMRule, 49 PMConversion* UPMToPMRule); 50 private: 51 GrConfigConversionEffect(GrTexture*, PMConversion, const SkMatrix& matrix); 52 53 GrConfigConversionEffect(GrResourceProvider*, sk_sp<GrTextureProxy>, 54 PMConversion, const SkMatrix& matrix); 55 56 GrGLSLFragmentProcessor* onCreateGLSLInstance() const override; 57 58 void onGetGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder*) const override; 59 60 bool onIsEqual(const GrFragmentProcessor&) const override; 61 62 PMConversion fPMConversion; 63 64 GR_DECLARE_FRAGMENT_PROCESSOR_TEST; 65 66 typedef GrSingleTextureEffect INHERITED; 67 }; 68 69 #endif 70
