src/third_party/skia/src/gpu/effects/GrDistanceFieldTextureEffect.h

   1 /*
   2  * Copyright 2013 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 GrDistanceFieldTextureEffect_DEFINED
   9 #define GrDistanceFieldTextureEffect_DEFINED
  10
  11 #include "GrProcessor.h"
  12 #include "GrGeometryProcessor.h"
  13
  14 class GrGLDistanceFieldTextureEffect;
  15 class GrGLDistanceFieldLCDTextureEffect;
  16
  17 enum GrDistanceFieldEffectFlags {
  18     kSimilarity_DistanceFieldEffectFlag = 0x01,   // ctm is similarity matrix
  19     kRectToRect_DistanceFieldEffectFlag = 0x02,   // ctm maps rects to rects
  20     kUseLCD_DistanceFieldEffectFlag     = 0x04,   // use lcd text
  21     kBGR_DistanceFieldEffectFlag        = 0x08,   // lcd display has bgr order
  22     kPortrait_DistanceFieldEffectFlag   = 0x10,   // lcd display is in portrait mode (not used yet)
  23
  24     kUniformScale_DistanceFieldEffectMask = kSimilarity_DistanceFieldEffectFlag |
  25                                             kRectToRect_DistanceFieldEffectFlag,
  26     // The subset of the flags relevant to GrDistanceFieldTextureEffect
  27     kNonLCD_DistanceFieldEffectMask       = kSimilarity_DistanceFieldEffectFlag,
  28     // The subset of the flags relevant to GrDistanceFieldLCDTextureEffect
  29     kLCD_DistanceFieldEffectMask          = kSimilarity_DistanceFieldEffectFlag |
  30                                             kRectToRect_DistanceFieldEffectFlag |
  31                                             kUseLCD_DistanceFieldEffectFlag |
  32                                             kBGR_DistanceFieldEffectFlag,
  33 };
  34
  35 /**
  36  * The output color of this effect is a modulation of the input color and a sample from a
  37  * distance field texture (using a smoothed step function near 0.5).
  38  * It allows explicit specification of the filtering and wrap modes (GrTextureParams). The input
  39  * coords are a custom attribute. Gamma correction is handled via a texture LUT.
  40  */
  41 class GrDistanceFieldTextureEffect : public GrGeometryProcessor {
  42 public:
  43 #ifdef SK_GAMMA_APPLY_TO_A8
  44     static GrGeometryProcessor* Create(GrTexture* tex, const GrTextureParams& params,
  45                                        GrTexture* gamma, const GrTextureParams& gammaParams,
  46                                        float lum, uint32_t flags) {
  47        return SkNEW_ARGS(GrDistanceFieldTextureEffect, (tex, params, gamma, gammaParams, lum,
  48                                                         flags));
  49     }
  50 #else
  51     static GrGeometryProcessor* Create(GrTexture* tex, const GrTextureParams& params,
  52                                        uint32_t flags) {
  53         return  SkNEW_ARGS(GrDistanceFieldTextureEffect, (tex, params, flags));
  54     }
  55 #endif
  56
  57     virtual ~GrDistanceFieldTextureEffect() {}
  58
  59     static const char* Name() { return "DistanceFieldTexture"; }
  60
  61     virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE;
  62
  63     const GrShaderVar& inTextureCoords() const { return fInTextureCoords; }
  64 #ifdef SK_GAMMA_APPLY_TO_A8
  65     float getLuminance() const { return fLuminance; }
  66 #endif
  67     uint32_t getFlags() const { return fFlags; }
  68
  69     typedef GrGLDistanceFieldTextureEffect GLProcessor;
  70
  71     virtual const GrBackendGeometryProcessorFactory& getFactory() const SK_OVERRIDE;
  72
  73 private:
  74     GrDistanceFieldTextureEffect(GrTexture* texture, const GrTextureParams& params,
  75 #ifdef SK_GAMMA_APPLY_TO_A8
  76                                  GrTexture* gamma, const GrTextureParams& gammaParams, float lum,
  77 #endif
  78                                  uint32_t flags);
  79
  80     virtual bool onIsEqual(const GrProcessor& other) const SK_OVERRIDE;
  81
  82     GrTextureAccess    fTextureAccess;
  83 #ifdef SK_GAMMA_APPLY_TO_A8
  84     GrTextureAccess    fGammaTextureAccess;
  85     float              fLuminance;
  86 #endif
  87     uint32_t           fFlags;
  88     const GrShaderVar& fInTextureCoords;
  89
  90     GR_DECLARE_GEOMETRY_PROCESSOR_TEST;
  91
  92     typedef GrFragmentProcessor INHERITED;
  93 };
  94
  95 /**
  96  * The output color of this effect is a modulation of the input color and samples from a
  97  * distance field texture (using a smoothed step function near 0.5), adjusted for LCD displays.
  98  * It allows explicit specification of the filtering and wrap modes (GrTextureParams). The input
  99  * coords are a custom attribute. Gamma correction is handled via a texture LUT.
 100  */
 101 class GrDistanceFieldLCDTextureEffect : public GrGeometryProcessor {
 102 public:
 103     static GrGeometryProcessor* Create(GrTexture* tex, const GrTextureParams& params,
 104                                        GrTexture* gamma, const GrTextureParams& gammaParams,
 105                                        SkColor textColor, uint32_t flags) {
 106         return SkNEW_ARGS(GrDistanceFieldLCDTextureEffect,
 107                           (tex, params, gamma, gammaParams, textColor, flags));
 108     }
 109
 110     virtual ~GrDistanceFieldLCDTextureEffect() {}
 111
 112     static const char* Name() { return "DistanceFieldLCDTexture"; }
 113
 114     const GrShaderVar& inTextureCoords() const { return fInTextureCoords; }
 115     virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE;
 116     GrColor getTextColor() const { return fTextColor; }
 117     uint32_t getFlags() const { return fFlags; }
 118
 119     typedef GrGLDistanceFieldLCDTextureEffect GLProcessor;
 120
 121     virtual const GrBackendGeometryProcessorFactory& getFactory() const SK_OVERRIDE;
 122
 123 private:
 124     GrDistanceFieldLCDTextureEffect(GrTexture* texture, const GrTextureParams& params,
 125                                     GrTexture* gamma, const GrTextureParams& gammaParams,
 126                                     SkColor textColor,
 127                                     uint32_t flags);
 128
 129     virtual bool onIsEqual(const GrProcessor& other) const SK_OVERRIDE;
 130
 131     GrTextureAccess    fTextureAccess;
 132     GrTextureAccess    fGammaTextureAccess;
 133     GrColor            fTextColor;
 134     uint32_t           fFlags;
 135     const GrShaderVar& fInTextureCoords;
 136
 137     GR_DECLARE_GEOMETRY_PROCESSOR_TEST;
 138
 139     typedef GrFragmentProcessor INHERITED;
 140 };
 141
 142 #endif