1 /*
2 * Copyright 2016 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 "GrSRGBEffect.h"
9
10 #include "GrFragmentProcessor.h"
11 #include "GrProcessor.h"
12 #include "glsl/GrGLSLFragmentProcessor.h"
13 #include "glsl/GrGLSLFragmentShaderBuilder.h"
14
15 class GrGLSRGBEffect : public GrGLSLFragmentProcessor {
16 public:
emitCode(EmitArgs & args)17 void emitCode(EmitArgs& args) override {
18 const GrSRGBEffect& srgbe = args.fFp.cast<GrSRGBEffect>();
19 GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
20
21 SkString srgbFuncName;
22 static const GrShaderVar gSrgbArgs[] = {
23 GrShaderVar("x", kFloat_GrSLType),
24 };
25 switch (srgbe.mode()) {
26 case GrSRGBEffect::Mode::kLinearToSRGB:
27 fragBuilder->emitFunction(kFloat_GrSLType,
28 "linear_to_srgb",
29 SK_ARRAY_COUNT(gSrgbArgs),
30 gSrgbArgs,
31 "return (x <= 0.0031308) ? (x * 12.92) "
32 ": (1.055 * pow(x, 0.416666667) - 0.055);",
33 &srgbFuncName);
34 break;
35 case GrSRGBEffect::Mode::kSRGBToLinear:
36 fragBuilder->emitFunction(kFloat_GrSLType,
37 "srgb_to_linear",
38 SK_ARRAY_COUNT(gSrgbArgs),
39 gSrgbArgs,
40 "return (x <= 0.04045) ? (x / 12.92) "
41 ": pow((x + 0.055) / 1.055, 2.4);",
42 &srgbFuncName);
43 break;
44 }
45
46 if (nullptr == args.fInputColor) {
47 args.fInputColor = "vec4(1)";
48 }
49
50 fragBuilder->codeAppendf("%s = vec4(%s(%s.r), %s(%s.g), %s(%s.b), %s.a);",
51 args.fOutputColor,
52 srgbFuncName.c_str(), args.fInputColor,
53 srgbFuncName.c_str(), args.fInputColor,
54 srgbFuncName.c_str(), args.fInputColor,
55 args.fInputColor);
56 }
57
GenKey(const GrProcessor & processor,const GrShaderCaps &,GrProcessorKeyBuilder * b)58 static inline void GenKey(const GrProcessor& processor, const GrShaderCaps&,
59 GrProcessorKeyBuilder* b) {
60 const GrSRGBEffect& srgbe = processor.cast<GrSRGBEffect>();
61 uint32_t key = static_cast<uint32_t>(srgbe.mode());
62 b->add32(key);
63 }
64
65 private:
66 typedef GrGLSLFragmentProcessor INHERITED;
67 };
68
69 ///////////////////////////////////////////////////////////////////////////////
70
GrSRGBEffect(Mode mode)71 GrSRGBEffect::GrSRGBEffect(Mode mode)
72 : INHERITED(kPreservesOpaqueInput_OptimizationFlag |
73 kConstantOutputForConstantInput_OptimizationFlag)
74 , fMode(mode) {
75 this->initClassID<GrSRGBEffect>();
76 }
77
onIsEqual(const GrFragmentProcessor & s) const78 bool GrSRGBEffect::onIsEqual(const GrFragmentProcessor& s) const {
79 const GrSRGBEffect& other = s.cast<GrSRGBEffect>();
80 return other.fMode == fMode;
81 }
82
srgb_to_linear(float srgb)83 static inline float srgb_to_linear(float srgb) {
84 return (srgb <= 0.04045f) ? srgb / 12.92f : powf((srgb + 0.055f) / 1.055f, 2.4f);
85 }
linear_to_srgb(float linear)86 static inline float linear_to_srgb(float linear) {
87 return (linear <= 0.0031308) ? linear * 12.92f : 1.055f * powf(linear, 1.f / 2.4f) - 0.055f;
88 }
89
constantOutputForConstantInput(GrColor4f input) const90 GrColor4f GrSRGBEffect::constantOutputForConstantInput(GrColor4f input) const {
91 switch (fMode) {
92 case Mode::kLinearToSRGB:
93 return GrColor4f(linear_to_srgb(input.fRGBA[0]), linear_to_srgb(input.fRGBA[1]),
94 linear_to_srgb(input.fRGBA[2]), input.fRGBA[3]);
95 case Mode::kSRGBToLinear:
96 return GrColor4f(srgb_to_linear(input.fRGBA[0]), srgb_to_linear(input.fRGBA[1]),
97 srgb_to_linear(input.fRGBA[2]), input.fRGBA[3]);
98 }
99 SkFAIL("Unexpected mode");
100 return GrColor4f::TransparentBlack();
101 }
102
103 ///////////////////////////////////////////////////////////////////////////////
104
105 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrSRGBEffect);
106
107 #if GR_TEST_UTILS
TestCreate(GrProcessorTestData * d)108 sk_sp<GrFragmentProcessor> GrSRGBEffect::TestCreate(GrProcessorTestData* d) {
109 Mode testMode = static_cast<Mode>(d->fRandom->nextRangeU(0, 1));
110 return sk_sp<GrFragmentProcessor>(new GrSRGBEffect(testMode));
111 }
112 #endif
113
114 ///////////////////////////////////////////////////////////////////////////////
115
onGetGLSLProcessorKey(const GrShaderCaps & caps,GrProcessorKeyBuilder * b) const116 void GrSRGBEffect::onGetGLSLProcessorKey(const GrShaderCaps& caps,
117 GrProcessorKeyBuilder* b) const {
118 GrGLSRGBEffect::GenKey(*this, caps, b);
119 }
120
onCreateGLSLInstance() const121 GrGLSLFragmentProcessor* GrSRGBEffect::onCreateGLSLInstance() const {
122 return new GrGLSRGBEffect();
123 }
124
Make(Mode mode)125 sk_sp<GrFragmentProcessor> GrSRGBEffect::Make(Mode mode) {
126 return sk_sp<GrFragmentProcessor>(new GrSRGBEffect(mode));
127 }
128