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 "GrProcessor.h"
10 #include "gl/GrGLXferProcessor.h"
11 #include "gl/builders/GrGLFragmentShaderBuilder.h"
12 #include "gl/builders/GrGLProgramBuilder.h"
13
14 /**
15 * This xfer processor disables color writing. Thus color and coverage and ignored and no blending
16 * occurs. This XP is usful for things like stenciling.
17 */
18 class DisableColorXP : public GrXferProcessor {
19 public:
Create()20 static GrXferProcessor* Create() {
21 return SkNEW(DisableColorXP);
22 }
23
~DisableColorXP()24 ~DisableColorXP() override {};
25
name() const26 const char* name() const override { return "Disable Color"; }
27
28 GrGLXferProcessor* createGLInstance() const override;
29
hasSecondaryOutput() const30 bool hasSecondaryOutput() const override { return false; }
31
32 private:
33 DisableColorXP();
34
onGetOptimizations(const GrProcOptInfo & colorPOI,const GrProcOptInfo & coveragePOI,bool doesStencilWrite,GrColor * color,const GrDrawTargetCaps & caps)35 GrXferProcessor::OptFlags onGetOptimizations(const GrProcOptInfo& colorPOI,
36 const GrProcOptInfo& coveragePOI,
37 bool doesStencilWrite,
38 GrColor* color,
39 const GrDrawTargetCaps& caps) override {
40 return GrXferProcessor::kIgnoreColor_OptFlag | GrXferProcessor::kIgnoreCoverage_OptFlag;
41 }
42
43 void onGetGLProcessorKey(const GrGLSLCaps& caps, GrProcessorKeyBuilder* b) const override;
44
45 void onGetBlendInfo(GrXferProcessor::BlendInfo* blendInfo) const override;
46
onIsEqual(const GrXferProcessor & xpBase) const47 bool onIsEqual(const GrXferProcessor& xpBase) const override {
48 return true;
49 }
50
51 typedef GrXferProcessor INHERITED;
52 };
53
54 ///////////////////////////////////////////////////////////////////////////////
55
56 class GLDisableColorXP : public GrGLXferProcessor {
57 public:
GLDisableColorXP(const GrProcessor &)58 GLDisableColorXP(const GrProcessor&) {}
59
~GLDisableColorXP()60 ~GLDisableColorXP() override {}
61
GenKey(const GrProcessor &,const GrGLSLCaps &,GrProcessorKeyBuilder *)62 static void GenKey(const GrProcessor&, const GrGLSLCaps&, GrProcessorKeyBuilder*) {}
63
64 private:
onEmitCode(const EmitArgs & args)65 void onEmitCode(const EmitArgs& args) override {
66 // This emit code should be empty. However, on the nexus 6 there is a driver bug where if
67 // you do not give gl_FragColor a value, the gl context is lost and we end up drawing
68 // nothing. So this fix just sets the gl_FragColor arbitrarily to 0.
69 GrGLXPFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
70 fsBuilder->codeAppendf("%s = vec4(0);", args.fOutputPrimary);
71 }
72
onSetData(const GrGLProgramDataManager &,const GrXferProcessor &)73 void onSetData(const GrGLProgramDataManager&, const GrXferProcessor&) override {}
74
75 typedef GrGLXferProcessor INHERITED;
76 };
77
78 ///////////////////////////////////////////////////////////////////////////////
79
DisableColorXP()80 DisableColorXP::DisableColorXP() {
81 this->initClassID<DisableColorXP>();
82 }
83
onGetGLProcessorKey(const GrGLSLCaps & caps,GrProcessorKeyBuilder * b) const84 void DisableColorXP::onGetGLProcessorKey(const GrGLSLCaps& caps, GrProcessorKeyBuilder* b) const {
85 GLDisableColorXP::GenKey(*this, caps, b);
86 }
87
createGLInstance() const88 GrGLXferProcessor* DisableColorXP::createGLInstance() const {
89 return SkNEW_ARGS(GLDisableColorXP, (*this));
90 }
91
onGetBlendInfo(GrXferProcessor::BlendInfo * blendInfo) const92 void DisableColorXP::onGetBlendInfo(GrXferProcessor::BlendInfo* blendInfo) const {
93 blendInfo->fWriteColor = false;
94 }
95
96 ///////////////////////////////////////////////////////////////////////////////
97
GrDisableColorXPFactory()98 GrDisableColorXPFactory::GrDisableColorXPFactory() {
99 this->initClassID<GrDisableColorXPFactory>();
100 }
101
102 GrXferProcessor*
onCreateXferProcessor(const GrDrawTargetCaps & caps,const GrProcOptInfo & colorPOI,const GrProcOptInfo & covPOI,const GrDeviceCoordTexture * dstCopy) const103 GrDisableColorXPFactory::onCreateXferProcessor(const GrDrawTargetCaps& caps,
104 const GrProcOptInfo& colorPOI,
105 const GrProcOptInfo& covPOI,
106 const GrDeviceCoordTexture* dstCopy) const {
107 return DisableColorXP::Create();
108 }
109
110 GR_DEFINE_XP_FACTORY_TEST(GrDisableColorXPFactory);
111
TestCreate(SkRandom * random,GrContext *,const GrDrawTargetCaps &,GrTexture * [])112 GrXPFactory* GrDisableColorXPFactory::TestCreate(SkRandom* random,
113 GrContext*,
114 const GrDrawTargetCaps&,
115 GrTexture*[]) {
116 return GrDisableColorXPFactory::Create();
117 }
118
119