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 "GrBicubicEffect.h"
9 #include "GrInvariantOutput.h"
10 #include "glsl/GrGLSLFragmentShaderBuilder.h"
11 #include "glsl/GrGLSLProgramDataManager.h"
12 #include "glsl/GrGLSLUniformHandler.h"
13
14 #define DS(x) SkDoubleToScalar(x)
15
16 const SkScalar GrBicubicEffect::gMitchellCoefficients[16] = {
17 DS( 1.0 / 18.0), DS(-9.0 / 18.0), DS( 15.0 / 18.0), DS( -7.0 / 18.0),
18 DS(16.0 / 18.0), DS( 0.0 / 18.0), DS(-36.0 / 18.0), DS( 21.0 / 18.0),
19 DS( 1.0 / 18.0), DS( 9.0 / 18.0), DS( 27.0 / 18.0), DS(-21.0 / 18.0),
20 DS( 0.0 / 18.0), DS( 0.0 / 18.0), DS( -6.0 / 18.0), DS( 7.0 / 18.0),
21 };
22
23
24 class GrGLBicubicEffect : public GrGLSLFragmentProcessor {
25 public:
26 void emitCode(EmitArgs&) override;
27
GenKey(const GrProcessor & effect,const GrGLSLCaps &,GrProcessorKeyBuilder * b)28 static inline void GenKey(const GrProcessor& effect, const GrGLSLCaps&,
29 GrProcessorKeyBuilder* b) {
30 const GrTextureDomain& domain = effect.cast<GrBicubicEffect>().domain();
31 b->add32(GrTextureDomain::GLDomain::DomainKey(domain));
32 }
33
34 protected:
35 void onSetData(const GrGLSLProgramDataManager&, const GrProcessor&) override;
36
37 private:
38 typedef GrGLSLProgramDataManager::UniformHandle UniformHandle;
39
40 UniformHandle fCoefficientsUni;
41 UniformHandle fImageIncrementUni;
42 GrTextureDomain::GLDomain fDomain;
43
44 typedef GrGLSLFragmentProcessor INHERITED;
45 };
46
emitCode(EmitArgs & args)47 void GrGLBicubicEffect::emitCode(EmitArgs& args) {
48 const GrTextureDomain& domain = args.fFp.cast<GrBicubicEffect>().domain();
49
50 GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
51 fCoefficientsUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
52 kMat44f_GrSLType, kDefault_GrSLPrecision,
53 "Coefficients");
54 fImageIncrementUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
55 kVec2f_GrSLType, kDefault_GrSLPrecision,
56 "ImageIncrement");
57
58 const char* imgInc = uniformHandler->getUniformCStr(fImageIncrementUni);
59 const char* coeff = uniformHandler->getUniformCStr(fCoefficientsUni);
60
61 SkString cubicBlendName;
62
63 static const GrGLSLShaderVar gCubicBlendArgs[] = {
64 GrGLSLShaderVar("coefficients", kMat44f_GrSLType),
65 GrGLSLShaderVar("t", kFloat_GrSLType),
66 GrGLSLShaderVar("c0", kVec4f_GrSLType),
67 GrGLSLShaderVar("c1", kVec4f_GrSLType),
68 GrGLSLShaderVar("c2", kVec4f_GrSLType),
69 GrGLSLShaderVar("c3", kVec4f_GrSLType),
70 };
71 GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
72 SkString coords2D = fragBuilder->ensureFSCoords2D(args.fCoords, 0);
73 fragBuilder->emitFunction(kVec4f_GrSLType,
74 "cubicBlend",
75 SK_ARRAY_COUNT(gCubicBlendArgs),
76 gCubicBlendArgs,
77 "\tvec4 ts = vec4(1.0, t, t * t, t * t * t);\n"
78 "\tvec4 c = coefficients * ts;\n"
79 "\treturn c.x * c0 + c.y * c1 + c.z * c2 + c.w * c3;\n",
80 &cubicBlendName);
81 fragBuilder->codeAppendf("\tvec2 coord = %s - %s * vec2(0.5);\n", coords2D.c_str(), imgInc);
82 // We unnormalize the coord in order to determine our fractional offset (f) within the texel
83 // We then snap coord to a texel center and renormalize. The snap prevents cases where the
84 // starting coords are near a texel boundary and accumulations of imgInc would cause us to skip/
85 // double hit a texel.
86 fragBuilder->codeAppendf("\tcoord /= %s;\n", imgInc);
87 fragBuilder->codeAppend("\tvec2 f = fract(coord);\n");
88 fragBuilder->codeAppendf("\tcoord = (coord - f + vec2(0.5)) * %s;\n", imgInc);
89 fragBuilder->codeAppend("\tvec4 rowColors[4];\n");
90 for (int y = 0; y < 4; ++y) {
91 for (int x = 0; x < 4; ++x) {
92 SkString coord;
93 coord.printf("coord + %s * vec2(%d, %d)", imgInc, x - 1, y - 1);
94 SkString sampleVar;
95 sampleVar.printf("rowColors[%d]", x);
96 fDomain.sampleTexture(fragBuilder,
97 args.fUniformHandler,
98 args.fGLSLCaps,
99 domain,
100 sampleVar.c_str(),
101 coord,
102 args.fSamplers[0]);
103 }
104 fragBuilder->codeAppendf(
105 "\tvec4 s%d = %s(%s, f.x, rowColors[0], rowColors[1], rowColors[2], rowColors[3]);\n",
106 y, cubicBlendName.c_str(), coeff);
107 }
108 SkString bicubicColor;
109 bicubicColor.printf("%s(%s, f.y, s0, s1, s2, s3)", cubicBlendName.c_str(), coeff);
110 fragBuilder->codeAppendf("\t%s = %s;\n",
111 args.fOutputColor, (GrGLSLExpr4(bicubicColor.c_str()) *
112 GrGLSLExpr4(args.fInputColor)).c_str());
113 }
114
onSetData(const GrGLSLProgramDataManager & pdman,const GrProcessor & processor)115 void GrGLBicubicEffect::onSetData(const GrGLSLProgramDataManager& pdman,
116 const GrProcessor& processor) {
117 const GrBicubicEffect& bicubicEffect = processor.cast<GrBicubicEffect>();
118 const GrTexture& texture = *processor.texture(0);
119 float imageIncrement[2];
120 imageIncrement[0] = 1.0f / texture.width();
121 imageIncrement[1] = 1.0f / texture.height();
122 pdman.set2fv(fImageIncrementUni, 1, imageIncrement);
123 pdman.setMatrix4f(fCoefficientsUni, bicubicEffect.coefficients());
124 fDomain.setData(pdman, bicubicEffect.domain(), texture.origin());
125 }
126
convert_row_major_scalar_coeffs_to_column_major_floats(float dst[16],const SkScalar src[16])127 static inline void convert_row_major_scalar_coeffs_to_column_major_floats(float dst[16],
128 const SkScalar src[16]) {
129 for (int y = 0; y < 4; y++) {
130 for (int x = 0; x < 4; x++) {
131 dst[x * 4 + y] = SkScalarToFloat(src[y * 4 + x]);
132 }
133 }
134 }
135
GrBicubicEffect(GrTexture * texture,const SkScalar coefficients[16],const SkMatrix & matrix,const SkShader::TileMode tileModes[2])136 GrBicubicEffect::GrBicubicEffect(GrTexture* texture,
137 const SkScalar coefficients[16],
138 const SkMatrix &matrix,
139 const SkShader::TileMode tileModes[2])
140 : INHERITED(texture, matrix, GrTextureParams(tileModes, GrTextureParams::kNone_FilterMode))
141 , fDomain(GrTextureDomain::IgnoredDomain()) {
142 this->initClassID<GrBicubicEffect>();
143 convert_row_major_scalar_coeffs_to_column_major_floats(fCoefficients, coefficients);
144 }
145
GrBicubicEffect(GrTexture * texture,const SkScalar coefficients[16],const SkMatrix & matrix,const SkRect & domain)146 GrBicubicEffect::GrBicubicEffect(GrTexture* texture,
147 const SkScalar coefficients[16],
148 const SkMatrix &matrix,
149 const SkRect& domain)
150 : INHERITED(texture, matrix,
151 GrTextureParams(SkShader::kClamp_TileMode, GrTextureParams::kNone_FilterMode))
152 , fDomain(domain, GrTextureDomain::kClamp_Mode) {
153 this->initClassID<GrBicubicEffect>();
154 convert_row_major_scalar_coeffs_to_column_major_floats(fCoefficients, coefficients);
155 }
156
~GrBicubicEffect()157 GrBicubicEffect::~GrBicubicEffect() {
158 }
159
onGetGLSLProcessorKey(const GrGLSLCaps & caps,GrProcessorKeyBuilder * b) const160 void GrBicubicEffect::onGetGLSLProcessorKey(const GrGLSLCaps& caps,
161 GrProcessorKeyBuilder* b) const {
162 GrGLBicubicEffect::GenKey(*this, caps, b);
163 }
164
onCreateGLSLInstance() const165 GrGLSLFragmentProcessor* GrBicubicEffect::onCreateGLSLInstance() const {
166 return new GrGLBicubicEffect;
167 }
168
onIsEqual(const GrFragmentProcessor & sBase) const169 bool GrBicubicEffect::onIsEqual(const GrFragmentProcessor& sBase) const {
170 const GrBicubicEffect& s = sBase.cast<GrBicubicEffect>();
171 return !memcmp(fCoefficients, s.coefficients(), 16) &&
172 fDomain == s.fDomain;
173 }
174
onComputeInvariantOutput(GrInvariantOutput * inout) const175 void GrBicubicEffect::onComputeInvariantOutput(GrInvariantOutput* inout) const {
176 // FIXME: Perhaps we can do better.
177 inout->mulByUnknownSingleComponent();
178 }
179
180 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrBicubicEffect);
181
TestCreate(GrProcessorTestData * d)182 const GrFragmentProcessor* GrBicubicEffect::TestCreate(GrProcessorTestData* d) {
183 int texIdx = d->fRandom->nextBool() ? GrProcessorUnitTest::kSkiaPMTextureIdx :
184 GrProcessorUnitTest::kAlphaTextureIdx;
185 SkScalar coefficients[16];
186 for (int i = 0; i < 16; i++) {
187 coefficients[i] = d->fRandom->nextSScalar1();
188 }
189 return GrBicubicEffect::Create(d->fTextures[texIdx], coefficients);
190 }
191
192 //////////////////////////////////////////////////////////////////////////////
193
ShouldUseBicubic(const SkMatrix & matrix,GrTextureParams::FilterMode * filterMode)194 bool GrBicubicEffect::ShouldUseBicubic(const SkMatrix& matrix,
195 GrTextureParams::FilterMode* filterMode) {
196 if (matrix.isIdentity()) {
197 *filterMode = GrTextureParams::kNone_FilterMode;
198 return false;
199 }
200
201 SkScalar scales[2];
202 if (!matrix.getMinMaxScales(scales) || scales[0] < SK_Scalar1) {
203 // Bicubic doesn't handle arbitrary minimization well, as src texels can be skipped
204 // entirely,
205 *filterMode = GrTextureParams::kMipMap_FilterMode;
206 return false;
207 }
208 // At this point if scales[1] == SK_Scalar1 then the matrix doesn't do any scaling.
209 if (scales[1] == SK_Scalar1) {
210 if (matrix.rectStaysRect() && SkScalarIsInt(matrix.getTranslateX()) &&
211 SkScalarIsInt(matrix.getTranslateY())) {
212 *filterMode = GrTextureParams::kNone_FilterMode;
213 } else {
214 // Use bilerp to handle rotation or fractional translation.
215 *filterMode = GrTextureParams::kBilerp_FilterMode;
216 }
217 return false;
218 }
219 // When we use the bicubic filtering effect each sample is read from the texture using
220 // nearest neighbor sampling.
221 *filterMode = GrTextureParams::kNone_FilterMode;
222 return true;
223 }
224