Line data    Source code

       1             : /*
       2             :  * Copyright 2014 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/GrDisableColorXP.h"
       9             : #include "GrPipeline.h"
      10             : #include "GrProcessor.h"
      11             : #include "glsl/GrGLSLFragmentShaderBuilder.h"
      12             : #include "glsl/GrGLSLProgramDataManager.h"
      13             : #include "glsl/GrGLSLXferProcessor.h"
      14             : 
      15             : /**
      16             :  * This xfer processor disables color writing. Thus color and coverage and ignored and no blending
      17             :  * occurs. This XP is usful for things like stenciling.
      18             :  */
      19           0 : class DisableColorXP : public GrXferProcessor {
      20             : public:
      21           0 :     DisableColorXP() { this->initClassID<DisableColorXP>(); }
      22             : 
      23           0 :     const char* name() const override { return "Disable Color"; }
      24             : 
      25             :     GrGLSLXferProcessor* createGLSLInstance() const override;
      26             : 
      27             : private:
      28             : 
      29             :     void onGetGLSLProcessorKey(const GrShaderCaps& caps, GrProcessorKeyBuilder* b) const override;
      30             : 
      31             :     void onGetBlendInfo(GrXferProcessor::BlendInfo* blendInfo) const override;
      32             : 
      33           0 :     bool onIsEqual(const GrXferProcessor& xpBase) const override {
      34           0 :         return true;
      35             :     }
      36             : 
      37             :     typedef GrXferProcessor INHERITED;
      38             : };
      39             : 
      40             : ///////////////////////////////////////////////////////////////////////////////
      41             : 
      42             : class GLDisableColorXP : public GrGLSLXferProcessor {
      43             : public:
      44           0 :     GLDisableColorXP(const GrProcessor&) {}
      45             : 
      46           0 :     ~GLDisableColorXP() override {}
      47             : 
      48           0 :     static void GenKey(const GrProcessor&, const GrShaderCaps&, GrProcessorKeyBuilder*) {}
      49             : 
      50             : private:
      51           0 :     void emitOutputsForBlendState(const EmitArgs& args) override {
      52             :         // This emit code should be empty. However, on the nexus 6 there is a driver bug where if
      53             :         // you do not give gl_FragColor a value, the gl context is lost and we end up drawing
      54             :         // nothing. So this fix just sets the gl_FragColor arbitrarily to 0.
      55           0 :         GrGLSLXPFragmentBuilder* fragBuilder = args.fXPFragBuilder;
      56           0 :         fragBuilder->codeAppendf("%s = vec4(0);", args.fOutputPrimary);
      57           0 :     }
      58             : 
      59           0 :     void onSetData(const GrGLSLProgramDataManager&, const GrXferProcessor&) override {}
      60             : 
      61             :     typedef GrGLSLXferProcessor INHERITED;
      62             : };
      63             : 
      64             : ///////////////////////////////////////////////////////////////////////////////
      65             : 
      66           0 : void DisableColorXP::onGetGLSLProcessorKey(const GrShaderCaps& caps, GrProcessorKeyBuilder* b) const {
      67           0 :     GLDisableColorXP::GenKey(*this, caps, b);
      68           0 : }
      69             : 
      70           0 : GrGLSLXferProcessor* DisableColorXP::createGLSLInstance() const { return new GLDisableColorXP(*this); }
      71             : 
      72           0 : void DisableColorXP::onGetBlendInfo(GrXferProcessor::BlendInfo* blendInfo) const {
      73           0 :     blendInfo->fWriteColor = false;
      74           0 : }
      75             : 
      76             : ///////////////////////////////////////////////////////////////////////////////
      77           0 : sk_sp<const GrXferProcessor> GrDisableColorXPFactory::makeXferProcessor(
      78             :         const GrProcessorAnalysisColor&,
      79             :         GrProcessorAnalysisCoverage,
      80             :         bool hasMixedSamples,
      81             :         const GrCaps& caps) const {
      82           0 :     return sk_sp<const GrXferProcessor>(new DisableColorXP);
      83             : }
      84             : 
      85             : GR_DEFINE_XP_FACTORY_TEST(GrDisableColorXPFactory);
      86             : 
      87             : #if GR_TEST_UTILS
      88           0 : const GrXPFactory* GrDisableColorXPFactory::TestGet(GrProcessorTestData*) {
      89           0 :     return GrDisableColorXPFactory::Get();
      90             : }
      91             : #endif