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1 /* | 1 /* |
2 * Copyright 2014 Google Inc. | 2 * Copyright 2014 Google Inc. |
3 * | 3 * |
4 * Use of this source code is governed by a BSD-style license that can be | 4 * Use of this source code is governed by a BSD-style license that can be |
5 * found in the LICENSE file. | 5 * found in the LICENSE file. |
6 */ | 6 */ |
7 | 7 |
8 #include "gl/builders/GrGLProgramBuilder.h" | 8 #include "gl/builders/GrGLProgramBuilder.h" |
9 #include "GrDitherEffect.h" | 9 #include "GrDitherEffect.h" |
10 | 10 |
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61 GrContext*, | 61 GrContext*, |
62 const GrDrawTargetCaps&, | 62 const GrDrawTargetCaps&, |
63 GrTexture*[]) { | 63 GrTexture*[]) { |
64 return DitherEffect::Create(); | 64 return DitherEffect::Create(); |
65 } | 65 } |
66 | 66 |
67 ////////////////////////////////////////////////////////////////////////////// | 67 ////////////////////////////////////////////////////////////////////////////// |
68 | 68 |
69 class GLDitherEffect : public GrGLEffect { | 69 class GLDitherEffect : public GrGLEffect { |
70 public: | 70 public: |
71 GLDitherEffect(const GrBackendEffectFactory&, const GrDrawEffect&); | 71 GLDitherEffect(const GrBackendEffectFactory&, const GrEffect&); |
72 | 72 |
73 virtual void emitCode(GrGLProgramBuilder* builder, | 73 virtual void emitCode(GrGLProgramBuilder* builder, |
74 const GrDrawEffect& drawEffect, | 74 const GrEffect& effect, |
75 const GrEffectKey& key, | 75 const GrEffectKey& key, |
76 const char* outputColor, | 76 const char* outputColor, |
77 const char* inputColor, | 77 const char* inputColor, |
78 const TransformedCoordsArray&, | 78 const TransformedCoordsArray&, |
79 const TextureSamplerArray&) SK_OVERRIDE; | 79 const TextureSamplerArray&) SK_OVERRIDE; |
80 | 80 |
81 private: | 81 private: |
82 typedef GrGLEffect INHERITED; | 82 typedef GrGLEffect INHERITED; |
83 }; | 83 }; |
84 | 84 |
85 GLDitherEffect::GLDitherEffect(const GrBackendEffectFactory& factory, | 85 GLDitherEffect::GLDitherEffect(const GrBackendEffectFactory& factory, |
86 const GrDrawEffect& drawEffect) | 86 const GrEffect& effect) |
87 : INHERITED (factory) { | 87 : INHERITED (factory) { |
88 } | 88 } |
89 | 89 |
90 void GLDitherEffect::emitCode(GrGLProgramBuilder* builder, | 90 void GLDitherEffect::emitCode(GrGLProgramBuilder* builder, |
91 const GrDrawEffect& drawEffect, | 91 const GrEffect& effect, |
92 const GrEffectKey& key, | 92 const GrEffectKey& key, |
93 const char* outputColor, | 93 const char* outputColor, |
94 const char* inputColor, | 94 const char* inputColor, |
95 const TransformedCoordsArray&, | 95 const TransformedCoordsArray&, |
96 const TextureSamplerArray& samplers) { | 96 const TextureSamplerArray& samplers) { |
97 GrGLFragmentShaderBuilder* fsBuilder = builder->getFragmentShaderBuilder(); | 97 GrGLFragmentShaderBuilder* fsBuilder = builder->getFragmentShaderBuilder(); |
98 // Generate a random number based on the fragment position. For this | 98 // Generate a random number based on the fragment position. For this |
99 // random number generator, we use the "GLSL rand" function | 99 // random number generator, we use the "GLSL rand" function |
100 // that seems to be floating around on the internet. It works under | 100 // that seems to be floating around on the internet. It works under |
101 // the assumption that sin(<big number>) oscillates with high frequency | 101 // the assumption that sin(<big number>) oscillates with high frequency |
102 // and sampling it will generate "randomness". Since we're using this | 102 // and sampling it will generate "randomness". Since we're using this |
103 // for rendering and not cryptography it should be OK. | 103 // for rendering and not cryptography it should be OK. |
104 | 104 |
105 // For each channel c, add the random offset to the pixel to either bump | 105 // For each channel c, add the random offset to the pixel to either bump |
106 // it up or let it remain constant during quantization. | 106 // it up or let it remain constant during quantization. |
107 fsBuilder->codeAppendf("\t\tfloat r = " | 107 fsBuilder->codeAppendf("\t\tfloat r = " |
108 "fract(sin(dot(%s.xy ,vec2(12.9898,78.233))) * 43758.
5453);\n", | 108 "fract(sin(dot(%s.xy ,vec2(12.9898,78.233))) * 43758.
5453);\n", |
109 fsBuilder->fragmentPosition()); | 109 fsBuilder->fragmentPosition()); |
110 fsBuilder->codeAppendf("\t\t%s = (1.0/255.0) * vec4(r, r, r, r) + %s;\n", | 110 fsBuilder->codeAppendf("\t\t%s = (1.0/255.0) * vec4(r, r, r, r) + %s;\n", |
111 outputColor, GrGLSLExpr4(inputColor).c_str()); | 111 outputColor, GrGLSLExpr4(inputColor).c_str()); |
112 } | 112 } |
113 | 113 |
114 ////////////////////////////////////////////////////////////////////////////// | 114 ////////////////////////////////////////////////////////////////////////////// |
115 | 115 |
116 GrEffect* GrDitherEffect::Create() { return DitherEffect::Create(); } | 116 GrEffect* GrDitherEffect::Create() { return DitherEffect::Create(); } |
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