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 "GrBicubicEffect.h"
9 :
10 : #include "GrProxyMove.h"
11 : #include "GrTextureProxy.h"
12 : #include "glsl/GrGLSLColorSpaceXformHelper.h"
13 : #include "glsl/GrGLSLFragmentShaderBuilder.h"
14 : #include "glsl/GrGLSLProgramDataManager.h"
15 : #include "glsl/GrGLSLUniformHandler.h"
16 : #include "../private/GrGLSL.h"
17 :
18 0 : class GrGLBicubicEffect : public GrGLSLFragmentProcessor {
19 : public:
20 : void emitCode(EmitArgs&) override;
21 :
22 0 : static inline void GenKey(const GrProcessor& effect, const GrShaderCaps&,
23 : GrProcessorKeyBuilder* b) {
24 0 : const GrBicubicEffect& bicubicEffect = effect.cast<GrBicubicEffect>();
25 0 : b->add32(GrTextureDomain::GLDomain::DomainKey(bicubicEffect.domain()));
26 0 : b->add32(GrColorSpaceXform::XformKey(bicubicEffect.colorSpaceXform()));
27 0 : }
28 :
29 : protected:
30 : void onSetData(const GrGLSLProgramDataManager&, const GrFragmentProcessor&) override;
31 :
32 : private:
33 : typedef GrGLSLProgramDataManager::UniformHandle UniformHandle;
34 :
35 : UniformHandle fImageIncrementUni;
36 : GrGLSLColorSpaceXformHelper fColorSpaceHelper;
37 : GrTextureDomain::GLDomain fDomain;
38 :
39 : typedef GrGLSLFragmentProcessor INHERITED;
40 : };
41 :
42 0 : void GrGLBicubicEffect::emitCode(EmitArgs& args) {
43 0 : const GrBicubicEffect& bicubicEffect = args.fFp.cast<GrBicubicEffect>();
44 :
45 0 : GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
46 : fImageIncrementUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
47 : kVec2f_GrSLType, kDefault_GrSLPrecision,
48 0 : "ImageIncrement");
49 :
50 0 : const char* imgInc = uniformHandler->getUniformCStr(fImageIncrementUni);
51 :
52 0 : fColorSpaceHelper.emitCode(uniformHandler, bicubicEffect.colorSpaceXform());
53 :
54 0 : GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
55 0 : SkString coords2D = fragBuilder->ensureCoords2D(args.fTransformedCoords[0]);
56 :
57 : /*
58 : * Filter weights come from Don Mitchell & Arun Netravali's 'Reconstruction Filters in Computer
59 : * Graphics', ACM SIGGRAPH Computer Graphics 22, 4 (Aug. 1988).
60 : * ACM DL: http://dl.acm.org/citation.cfm?id=378514
61 : * Free : http://www.cs.utexas.edu/users/fussell/courses/cs384g/lectures/mitchell/Mitchell.pdf
62 : *
63 : * The authors define a family of cubic filters with two free parameters (B and C):
64 : *
65 : * { (12 - 9B - 6C)|x|^3 + (-18 + 12B + 6C)|x|^2 + (6 - 2B) if |x| < 1
66 : * k(x) = 1/6 { (-B - 6C)|x|^3 + (6B + 30C)|x|^2 + (-12B - 48C)|x| + (8B + 24C) if 1 <= |x| < 2
67 : * { 0 otherwise
68 : *
69 : * Various well-known cubic splines can be generated, and the authors select (1/3, 1/3) as their
70 : * favorite overall spline - this is now commonly known as the Mitchell filter, and is the
71 : * source of the specific weights below.
72 : *
73 : * This is GLSL, so the matrix is column-major (transposed from standard matrix notation).
74 : */
75 0 : fragBuilder->codeAppend("mat4 kMitchellCoefficients = mat4("
76 : " 1.0 / 18.0, 16.0 / 18.0, 1.0 / 18.0, 0.0 / 18.0,"
77 : "-9.0 / 18.0, 0.0 / 18.0, 9.0 / 18.0, 0.0 / 18.0,"
78 : "15.0 / 18.0, -36.0 / 18.0, 27.0 / 18.0, -6.0 / 18.0,"
79 0 : "-7.0 / 18.0, 21.0 / 18.0, -21.0 / 18.0, 7.0 / 18.0);");
80 0 : fragBuilder->codeAppendf("vec2 coord = %s - %s * vec2(0.5);", coords2D.c_str(), imgInc);
81 : // We unnormalize the coord in order to determine our fractional offset (f) within the texel
82 : // We then snap coord to a texel center and renormalize. The snap prevents cases where the
83 : // starting coords are near a texel boundary and accumulations of imgInc would cause us to skip/
84 : // double hit a texel.
85 0 : fragBuilder->codeAppendf("coord /= %s;", imgInc);
86 0 : fragBuilder->codeAppend("vec2 f = fract(coord);");
87 0 : fragBuilder->codeAppendf("coord = (coord - f + vec2(0.5)) * %s;", imgInc);
88 0 : fragBuilder->codeAppend("vec4 wx = kMitchellCoefficients * vec4(1.0, f.x, f.x * f.x, f.x * f.x * f.x);");
89 0 : fragBuilder->codeAppend("vec4 wy = kMitchellCoefficients * vec4(1.0, f.y, f.y * f.y, f.y * f.y * f.y);");
90 0 : fragBuilder->codeAppend("vec4 rowColors[4];");
91 0 : for (int y = 0; y < 4; ++y) {
92 0 : for (int x = 0; x < 4; ++x) {
93 0 : SkString coord;
94 0 : coord.printf("coord + %s * vec2(%d, %d)", imgInc, x - 1, y - 1);
95 0 : SkString sampleVar;
96 0 : sampleVar.printf("rowColors[%d]", x);
97 0 : fDomain.sampleTexture(fragBuilder,
98 : args.fUniformHandler,
99 : args.fShaderCaps,
100 : bicubicEffect.domain(),
101 : sampleVar.c_str(),
102 : coord,
103 0 : args.fTexSamplers[0]);
104 : }
105 0 : fragBuilder->codeAppendf(
106 : "vec4 s%d = wx.x * rowColors[0] + wx.y * rowColors[1] + wx.z * rowColors[2] + wx.w * rowColors[3];",
107 0 : y);
108 : }
109 0 : SkString bicubicColor("(wy.x * s0 + wy.y * s1 + wy.z * s2 + wy.w * s3)");
110 0 : if (fColorSpaceHelper.isValid()) {
111 0 : SkString xformedColor;
112 0 : fragBuilder->appendColorGamutXform(&xformedColor, bicubicColor.c_str(), &fColorSpaceHelper);
113 0 : bicubicColor.swap(xformedColor);
114 : }
115 0 : fragBuilder->codeAppendf("%s = %s;",
116 0 : args.fOutputColor, (GrGLSLExpr4(bicubicColor.c_str()) *
117 0 : GrGLSLExpr4(args.fInputColor)).c_str());
118 0 : }
119 :
120 0 : void GrGLBicubicEffect::onSetData(const GrGLSLProgramDataManager& pdman,
121 : const GrFragmentProcessor& processor) {
122 0 : const GrBicubicEffect& bicubicEffect = processor.cast<GrBicubicEffect>();
123 0 : GrTexture* texture = processor.textureSampler(0).texture();
124 : float imageIncrement[2];
125 0 : imageIncrement[0] = 1.0f / texture->width();
126 0 : imageIncrement[1] = 1.0f / texture->height();
127 0 : pdman.set2fv(fImageIncrementUni, 1, imageIncrement);
128 0 : fDomain.setData(pdman, bicubicEffect.domain(), texture);
129 0 : if (SkToBool(bicubicEffect.colorSpaceXform())) {
130 0 : fColorSpaceHelper.setData(pdman, bicubicEffect.colorSpaceXform());
131 : }
132 0 : }
133 :
134 0 : GrBicubicEffect::GrBicubicEffect(GrResourceProvider* resourceProvider, sk_sp<GrTextureProxy> proxy,
135 : sk_sp<GrColorSpaceXform> colorSpaceXform,
136 : const SkMatrix &matrix,
137 0 : const SkShader::TileMode tileModes[2])
138 : : INHERITED{resourceProvider,
139 0 : ModulationFlags(proxy->config()),
140 0 : GR_PROXY_MOVE(proxy),
141 0 : std::move(colorSpaceXform),
142 : matrix,
143 0 : GrSamplerParams(tileModes, GrSamplerParams::kNone_FilterMode)}
144 0 : , fDomain(GrTextureDomain::IgnoredDomain()) {
145 0 : this->initClassID<GrBicubicEffect>();
146 0 : }
147 :
148 0 : GrBicubicEffect::GrBicubicEffect(GrResourceProvider* resourceProvider, sk_sp<GrTextureProxy> proxy,
149 : sk_sp<GrColorSpaceXform> colorSpaceXform,
150 : const SkMatrix &matrix,
151 0 : const SkRect& domain)
152 0 : : INHERITED(resourceProvider, ModulationFlags(proxy->config()), proxy,
153 0 : std::move(colorSpaceXform), matrix,
154 0 : GrSamplerParams(SkShader::kClamp_TileMode, GrSamplerParams::kNone_FilterMode))
155 0 : , fDomain(proxy.get(), domain, GrTextureDomain::kClamp_Mode) {
156 0 : this->initClassID<GrBicubicEffect>();
157 0 : }
158 :
159 0 : GrBicubicEffect::~GrBicubicEffect() {
160 0 : }
161 :
162 0 : void GrBicubicEffect::onGetGLSLProcessorKey(const GrShaderCaps& caps,
163 : GrProcessorKeyBuilder* b) const {
164 0 : GrGLBicubicEffect::GenKey(*this, caps, b);
165 0 : }
166 :
167 0 : GrGLSLFragmentProcessor* GrBicubicEffect::onCreateGLSLInstance() const {
168 0 : return new GrGLBicubicEffect;
169 : }
170 :
171 0 : bool GrBicubicEffect::onIsEqual(const GrFragmentProcessor& sBase) const {
172 0 : const GrBicubicEffect& s = sBase.cast<GrBicubicEffect>();
173 0 : return fDomain == s.fDomain;
174 : }
175 :
176 : GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrBicubicEffect);
177 :
178 : #if GR_TEST_UTILS
179 0 : sk_sp<GrFragmentProcessor> GrBicubicEffect::TestCreate(GrProcessorTestData* d) {
180 0 : int texIdx = d->fRandom->nextBool() ? GrProcessorUnitTest::kSkiaPMTextureIdx
181 0 : : GrProcessorUnitTest::kAlphaTextureIdx;
182 0 : sk_sp<GrColorSpaceXform> colorSpaceXform = GrTest::TestColorXform(d->fRandom);
183 : static const SkShader::TileMode kClampClamp[] =
184 : { SkShader::kClamp_TileMode, SkShader::kClamp_TileMode };
185 : return GrBicubicEffect::Make(d->resourceProvider(),
186 0 : d->textureProxy(texIdx), std::move(colorSpaceXform),
187 0 : SkMatrix::I(), kClampClamp);
188 : }
189 : #endif
190 :
191 : //////////////////////////////////////////////////////////////////////////////
192 :
193 0 : bool GrBicubicEffect::ShouldUseBicubic(const SkMatrix& matrix,
194 : GrSamplerParams::FilterMode* filterMode) {
195 0 : if (matrix.isIdentity()) {
196 0 : *filterMode = GrSamplerParams::kNone_FilterMode;
197 0 : return false;
198 : }
199 :
200 : SkScalar scales[2];
201 0 : if (!matrix.getMinMaxScales(scales) || scales[0] < SK_Scalar1) {
202 : // Bicubic doesn't handle arbitrary minimization well, as src texels can be skipped
203 : // entirely,
204 0 : *filterMode = GrSamplerParams::kMipMap_FilterMode;
205 0 : return false;
206 : }
207 : // At this point if scales[1] == SK_Scalar1 then the matrix doesn't do any scaling.
208 0 : if (scales[1] == SK_Scalar1) {
209 0 : if (matrix.rectStaysRect() && SkScalarIsInt(matrix.getTranslateX()) &&
210 0 : SkScalarIsInt(matrix.getTranslateY())) {
211 0 : *filterMode = GrSamplerParams::kNone_FilterMode;
212 : } else {
213 : // Use bilerp to handle rotation or fractional translation.
214 0 : *filterMode = GrSamplerParams::kBilerp_FilterMode;
215 : }
216 0 : return false;
217 : }
218 : // When we use the bicubic filtering effect each sample is read from the texture using
219 : // nearest neighbor sampling.
220 0 : *filterMode = GrSamplerParams::kNone_FilterMode;
221 0 : return true;
222 : }
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