src/gpu/effects/GrConstColorProcessor.cpp

   1 /*
   2  * Copyright 2015 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 "effects/GrConstColorProcessor.h"
   9 #include "glsl/GrGLSLFragmentProcessor.h"
  10 #include "glsl/GrGLSLFragmentShaderBuilder.h"
  11 #include "glsl/GrGLSLProgramBuilder.h"
  12 #include "glsl/GrGLSLProgramDataManager.h"
  13
  14 class GLConstColorProcessor : public GrGLSLFragmentProcessor {
  15 public:
  16     GLConstColorProcessor() : fPrevColor(GrColor_ILLEGAL) {}
  17
  18     void emitCode(EmitArgs& args) override {
  19         GrGLSLFragmentBuilder* fragBuilder = args.fFragBuilder;
  20         const char* colorUni;
  21         fColorUniform = args.fBuilder->addUniform(GrGLSLProgramBuilder::kFragment_Visibility,
  22                                             kVec4f_GrSLType, kMedium_GrSLPrecision, "constantColor",
  23                                             &colorUni);
  24         GrConstColorProcessor::InputMode mode = args.fFp.cast<GrConstColorProcessor>().inputMode();
  25         if (!args.fInputColor) {
  26             mode = GrConstColorProcessor::kIgnore_InputMode;
  27         }
  28         switch (mode) {
  29             case GrConstColorProcessor::kIgnore_InputMode:
  30                 fragBuilder->codeAppendf("%s = %s;", args.fOutputColor, colorUni);
  31                 break;
  32             case GrConstColorProcessor::kModulateRGBA_InputMode:
  33                 fragBuilder->codeAppendf("%s = %s * %s;", args.fOutputColor, args.fInputColor,
  34                                        colorUni);
  35                 break;
  36             case GrConstColorProcessor::kModulateA_InputMode:
  37                 fragBuilder->codeAppendf("%s = %s.a * %s;", args.fOutputColor, args.fInputColor,
  38                                        colorUni);
  39                 break;
  40         }
  41     }
  42
  43 protected:
  44     void onSetData(const GrGLSLProgramDataManager& pdm, const GrProcessor& processor) override {
  45         GrColor color = processor.cast<GrConstColorProcessor>().color();
  46         // We use the "illegal" color value as an uninit sentinel. However, ut isn't inherently
  47         // illegal to use this processor with unpremul colors. So we correctly handle the case
  48         // when the "illegal" color is used but we will always upload it.
  49         if (GrColor_ILLEGAL == color || fPrevColor != color) {
  50             static const float scale = 1.f / 255.f;
  51             float floatColor[4] = {
  52                 GrColorUnpackR(color) * scale,
  53                 GrColorUnpackG(color) * scale,
  54                 GrColorUnpackB(color) * scale,
  55                 GrColorUnpackA(color) * scale,
  56             };
  57             pdm.set4fv(fColorUniform, 1, floatColor);
  58             fPrevColor = color;
  59         }
  60     }
  61
  62 private:
  63     GrGLSLProgramDataManager::UniformHandle fColorUniform;
  64     GrColor                               fPrevColor;
  65
  66     typedef GrGLSLFragmentProcessor INHERITED;
  67 };
  68
  69 ///////////////////////////////////////////////////////////////////////////////
  70
  71 void GrConstColorProcessor::onComputeInvariantOutput(GrInvariantOutput* inout) const {
  72     if (kIgnore_InputMode == fMode) {
  73         inout->setToOther(kRGBA_GrColorComponentFlags, fColor,
  74                           GrInvariantOutput::kWillNot_ReadInput);
  75     } else {
  76         GrColor r = GrColorUnpackR(fColor);
  77         bool colorIsSingleChannel = r == GrColorUnpackG(fColor) && r == GrColorUnpackB(fColor) &&
  78                                     r == GrColorUnpackA(fColor);
  79         if (kModulateRGBA_InputMode == fMode) {
  80             if (colorIsSingleChannel) {
  81                 inout->mulByKnownSingleComponent(r);
  82             } else {
  83                 inout->mulByKnownFourComponents(fColor);
  84             }
  85         } else {
  86             if (colorIsSingleChannel) {
  87                 inout->mulAlphaByKnownSingleComponent(r);
  88             } else {
  89                 inout->mulAlphaByKnownFourComponents(fColor);
  90             }
  91         }
  92     }
  93 }
  94
  95 void GrConstColorProcessor::onGetGLSLProcessorKey(const GrGLSLCaps&,
  96                                                   GrProcessorKeyBuilder* b) const {
  97     b->add32(fMode);
  98 }
  99
 100 GrGLSLFragmentProcessor* GrConstColorProcessor::onCreateGLSLInstance() const  {
 101     return new GLConstColorProcessor;
 102 }
 103
 104 bool GrConstColorProcessor::onIsEqual(const GrFragmentProcessor& other) const {
 105     const GrConstColorProcessor& that = other.cast<GrConstColorProcessor>();
 106     return fMode == that.fMode && fColor == that.fColor;
 107 }
 108
 109 ///////////////////////////////////////////////////////////////////////////////
 110
 111 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrConstColorProcessor);
 112
 113 const GrFragmentProcessor* GrConstColorProcessor::TestCreate(GrProcessorTestData* d) {
 114     GrColor color;
 115     int colorPicker = d->fRandom->nextULessThan(3);
 116     switch (colorPicker) {
 117         case 0: {
 118             uint32_t a = d->fRandom->nextULessThan(0x100);
 119             uint32_t r = d->fRandom->nextULessThan(a+1);
 120             uint32_t g = d->fRandom->nextULessThan(a+1);
 121             uint32_t b = d->fRandom->nextULessThan(a+1);
 122             color = GrColorPackRGBA(r, g, b, a);
 123             break;
 124         }
 125         case 1:
 126             color = 0;
 127             break;
 128         case 2:
 129             color = d->fRandom->nextULessThan(0x100);
 130             color = color | (color << 8) | (color << 16) | (color << 24);
 131             break;
 132     }
 133     InputMode mode = static_cast<InputMode>(d->fRandom->nextULessThan(kInputModeCnt));
 134     return GrConstColorProcessor::Create(color, mode);
 135 }