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 "src/core/SkMatrixPriv.h"
9 #include "src/gpu/effects/GrBicubicEffect.h"
10
11 #include "include/gpu/GrTexture.h"
12 #include "src/gpu/glsl/GrGLSLFragmentShaderBuilder.h"
13 #include "src/gpu/glsl/GrGLSLProgramDataManager.h"
14 #include "src/gpu/glsl/GrGLSLUniformHandler.h"
15
16 class GrGLBicubicEffect : public GrGLSLFragmentProcessor {
17 public:
18 void emitCode(EmitArgs&) override;
19
GenKey(const GrProcessor & effect,const GrShaderCaps &,GrProcessorKeyBuilder * b)20 static inline void GenKey(const GrProcessor& effect, const GrShaderCaps&,
21 GrProcessorKeyBuilder* b) {
22 const GrBicubicEffect& bicubicEffect = effect.cast<GrBicubicEffect>();
23 b->add32(GrTextureDomain::GLDomain::DomainKey(bicubicEffect.domain()));
24 uint32_t bidir = bicubicEffect.direction() == GrBicubicEffect::Direction::kXY ? 1 : 0;
25 b->add32(bidir | (bicubicEffect.alphaType() << 1));
26 }
27
28 protected:
29 void onSetData(const GrGLSLProgramDataManager&, const GrFragmentProcessor&) override;
30
31 private:
32 typedef GrGLSLProgramDataManager::UniformHandle UniformHandle;
33
34 UniformHandle fDimensions;
35 GrTextureDomain::GLDomain fDomain;
36
37 typedef GrGLSLFragmentProcessor INHERITED;
38 };
39
emitCode(EmitArgs & args)40 void GrGLBicubicEffect::emitCode(EmitArgs& args) {
41 const GrBicubicEffect& bicubicEffect = args.fFp.cast<GrBicubicEffect>();
42
43 GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
44 fDimensions = uniformHandler->addUniform(kFragment_GrShaderFlag, kHalf4_GrSLType, "Dimensions");
45
46 const char* dims = uniformHandler->getUniformCStr(fDimensions);
47
48 GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
49 SkString coords2D = fragBuilder->ensureCoords2D(args.fTransformedCoords[0]);
50
51 /*
52 * Filter weights come from Don Mitchell & Arun Netravali's 'Reconstruction Filters in Computer
53 * Graphics', ACM SIGGRAPH Computer Graphics 22, 4 (Aug. 1988).
54 * ACM DL: http://dl.acm.org/citation.cfm?id=378514
55 * Free : http://www.cs.utexas.edu/users/fussell/courses/cs384g/lectures/mitchell/Mitchell.pdf
56 *
57 * The authors define a family of cubic filters with two free parameters (B and C):
58 *
59 * { (12 - 9B - 6C)|x|^3 + (-18 + 12B + 6C)|x|^2 + (6 - 2B) if |x| < 1
60 * k(x) = 1/6 { (-B - 6C)|x|^3 + (6B + 30C)|x|^2 + (-12B - 48C)|x| + (8B + 24C) if 1 <= |x| < 2
61 * { 0 otherwise
62 *
63 * Various well-known cubic splines can be generated, and the authors select (1/3, 1/3) as their
64 * favorite overall spline - this is now commonly known as the Mitchell filter, and is the
65 * source of the specific weights below.
66 *
67 * This is GLSL, so the matrix is column-major (transposed from standard matrix notation).
68 */
69 fragBuilder->codeAppend("half4x4 kMitchellCoefficients = half4x4("
70 " 1.0 / 18.0, 16.0 / 18.0, 1.0 / 18.0, 0.0 / 18.0,"
71 "-9.0 / 18.0, 0.0 / 18.0, 9.0 / 18.0, 0.0 / 18.0,"
72 "15.0 / 18.0, -36.0 / 18.0, 27.0 / 18.0, -6.0 / 18.0,"
73 "-7.0 / 18.0, 21.0 / 18.0, -21.0 / 18.0, 7.0 / 18.0);");
74 fragBuilder->codeAppendf("float2 coord = %s - %s.xy * float2(0.5);", coords2D.c_str(), dims);
75 // We unnormalize the coord in order to determine our fractional offset (f) within the texel
76 // We then snap coord to a texel center and renormalize. The snap prevents cases where the
77 // starting coords are near a texel boundary and accumulations of dims would cause us to skip/
78 // double hit a texel.
79 fragBuilder->codeAppendf("half2 f = half2(fract(coord * %s.zw));", dims);
80 fragBuilder->codeAppendf("coord = coord + (half2(0.5) - f) * %s.xy;", dims);
81 if (bicubicEffect.direction() == GrBicubicEffect::Direction::kXY) {
82 fragBuilder->codeAppend(
83 "half4 wx = kMitchellCoefficients * half4(1.0, f.x, f.x * f.x, f.x * f.x * f.x);");
84 fragBuilder->codeAppend(
85 "half4 wy = kMitchellCoefficients * half4(1.0, f.y, f.y * f.y, f.y * f.y * f.y);");
86 fragBuilder->codeAppend("half4 rowColors[4];");
87 for (int y = 0; y < 4; ++y) {
88 for (int x = 0; x < 4; ++x) {
89 SkString coord;
90 coord.printf("coord + %s.xy * float2(%d, %d)", dims, x - 1, y - 1);
91 SkString sampleVar;
92 sampleVar.printf("rowColors[%d]", x);
93 fDomain.sampleTexture(fragBuilder,
94 args.fUniformHandler,
95 args.fShaderCaps,
96 bicubicEffect.domain(),
97 sampleVar.c_str(),
98 coord,
99 args.fTexSamplers[0]);
100 }
101 fragBuilder->codeAppendf(
102 "half4 s%d = wx.x * rowColors[0] + wx.y * rowColors[1] + wx.z * rowColors[2] + "
103 "wx.w * rowColors[3];",
104 y);
105 }
106 fragBuilder->codeAppend(
107 "half4 bicubicColor = wy.x * s0 + wy.y * s1 + wy.z * s2 + wy.w * s3;");
108 } else {
109 // One of the dims.xy values will be zero. So v here selects the nonzero value of f.
110 fragBuilder->codeAppend("half v = f.x + f.y;");
111 fragBuilder->codeAppend("half v2 = v * v;");
112 fragBuilder->codeAppend("half4 w = kMitchellCoefficients * half4(1.0, v, v2, v2 * v);");
113 fragBuilder->codeAppend("half4 c[4];");
114 for (int i = 0; i < 4; ++i) {
115 SkString coord;
116 coord.printf("coord + %s.xy * half(%d)", dims, i - 1);
117 SkString samplerVar;
118 samplerVar.printf("c[%d]", i);
119 // With added complexity we could apply the domain once in X or Y depending on
120 // direction rather than for each of the four lookups, but then we might not be
121 // be able to share code for Direction::kX and ::kY.
122 fDomain.sampleTexture(fragBuilder,
123 args.fUniformHandler,
124 args.fShaderCaps,
125 bicubicEffect.domain(),
126 samplerVar.c_str(),
127 coord,
128 args.fTexSamplers[0]);
129 }
130 fragBuilder->codeAppend(
131 "half4 bicubicColor = c[0] * w.x + c[1] * w.y + c[2] * w.z + c[3] * w.w;");
132 }
133 // Bicubic can send colors out of range, so clamp to get them back in (source) gamut.
134 // The kind of clamp we have to do depends on the alpha type.
135 if (kPremul_SkAlphaType == bicubicEffect.alphaType()) {
136 fragBuilder->codeAppend("bicubicColor.a = saturate(bicubicColor.a);");
137 fragBuilder->codeAppend(
138 "bicubicColor.rgb = max(half3(0.0), min(bicubicColor.rgb, bicubicColor.aaa));");
139 } else {
140 fragBuilder->codeAppend("bicubicColor = saturate(bicubicColor);");
141 }
142 fragBuilder->codeAppendf("%s = bicubicColor * %s;", args.fOutputColor, args.fInputColor);
143 }
144
onSetData(const GrGLSLProgramDataManager & pdman,const GrFragmentProcessor & processor)145 void GrGLBicubicEffect::onSetData(const GrGLSLProgramDataManager& pdman,
146 const GrFragmentProcessor& processor) {
147 const GrBicubicEffect& bicubicEffect = processor.cast<GrBicubicEffect>();
148 GrTextureProxy* proxy = processor.textureSampler(0).proxy();
149 GrTexture* texture = proxy->peekTexture();
150
151 float dims[4] = {0, 0, 0, 0};
152 if (bicubicEffect.direction() != GrBicubicEffect::Direction::kY) {
153 dims[0] = 1.0f / texture->width();
154 dims[2] = texture->width();
155 }
156 if (bicubicEffect.direction() != GrBicubicEffect::Direction::kX) {
157 dims[1] = 1.0f / texture->height();
158 dims[3] = texture->height();
159 }
160 pdman.set4fv(fDimensions, 1, dims);
161 fDomain.setData(pdman, bicubicEffect.domain(), proxy,
162 processor.textureSampler(0).samplerState());
163 }
164
GrBicubicEffect(sk_sp<GrTextureProxy> proxy,const SkMatrix & matrix,const SkRect & domain,const GrSamplerState::WrapMode wrapModes[2],GrTextureDomain::Mode modeX,GrTextureDomain::Mode modeY,Direction direction,SkAlphaType alphaType)165 GrBicubicEffect::GrBicubicEffect(sk_sp<GrTextureProxy> proxy, const SkMatrix& matrix,
166 const SkRect& domain, const GrSamplerState::WrapMode wrapModes[2],
167 GrTextureDomain::Mode modeX, GrTextureDomain::Mode modeY,
168 Direction direction, SkAlphaType alphaType)
169 : INHERITED{kGrBicubicEffect_ClassID,
170 ModulateForSamplerOptFlags(
171 proxy->config(),
172 GrTextureDomain::IsDecalSampled(wrapModes, modeX, modeY))}
173 , fCoordTransform(matrix, proxy.get())
174 , fDomain(proxy.get(), domain, modeX, modeY)
175 , fTextureSampler(std::move(proxy),
176 GrSamplerState(wrapModes, GrSamplerState::Filter::kNearest))
177 , fAlphaType(alphaType)
178 , fDirection(direction) {
179 this->addCoordTransform(&fCoordTransform);
180 this->setTextureSamplerCnt(1);
181 }
182
GrBicubicEffect(const GrBicubicEffect & that)183 GrBicubicEffect::GrBicubicEffect(const GrBicubicEffect& that)
184 : INHERITED(kGrBicubicEffect_ClassID, that.optimizationFlags())
185 , fCoordTransform(that.fCoordTransform)
186 , fDomain(that.fDomain)
187 , fTextureSampler(that.fTextureSampler)
188 , fAlphaType(that.fAlphaType)
189 , fDirection(that.fDirection) {
190 this->addCoordTransform(&fCoordTransform);
191 this->setTextureSamplerCnt(1);
192 }
193
onGetGLSLProcessorKey(const GrShaderCaps & caps,GrProcessorKeyBuilder * b) const194 void GrBicubicEffect::onGetGLSLProcessorKey(const GrShaderCaps& caps,
195 GrProcessorKeyBuilder* b) const {
196 GrGLBicubicEffect::GenKey(*this, caps, b);
197 }
198
onCreateGLSLInstance() const199 GrGLSLFragmentProcessor* GrBicubicEffect::onCreateGLSLInstance() const {
200 return new GrGLBicubicEffect;
201 }
202
onIsEqual(const GrFragmentProcessor & sBase) const203 bool GrBicubicEffect::onIsEqual(const GrFragmentProcessor& sBase) const {
204 const GrBicubicEffect& s = sBase.cast<GrBicubicEffect>();
205 return fDomain == s.fDomain && fDirection == s.fDirection && fAlphaType == s.fAlphaType;
206 }
207
208 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrBicubicEffect);
209
210 #if GR_TEST_UTILS
TestCreate(GrProcessorTestData * d)211 std::unique_ptr<GrFragmentProcessor> GrBicubicEffect::TestCreate(GrProcessorTestData* d) {
212 int texIdx = d->fRandom->nextBool() ? GrProcessorUnitTest::kSkiaPMTextureIdx
213 : GrProcessorUnitTest::kAlphaTextureIdx;
214 static const GrSamplerState::WrapMode kClampClamp[] = {GrSamplerState::WrapMode::kClamp,
215 GrSamplerState::WrapMode::kClamp};
216 SkAlphaType alphaType = d->fRandom->nextBool() ? kPremul_SkAlphaType : kUnpremul_SkAlphaType;
217 Direction direction = Direction::kX;
218 switch (d->fRandom->nextULessThan(3)) {
219 case 0:
220 direction = Direction::kX;
221 break;
222 case 1:
223 direction = Direction::kY;
224 break;
225 case 2:
226 direction = Direction::kXY;
227 break;
228 }
229 return GrBicubicEffect::Make(d->textureProxy(texIdx), SkMatrix::I(), kClampClamp, direction,
230 alphaType);
231 }
232 #endif
233
234 //////////////////////////////////////////////////////////////////////////////
235
ShouldUseBicubic(const SkMatrix & matrix,GrSamplerState::Filter * filterMode)236 bool GrBicubicEffect::ShouldUseBicubic(const SkMatrix& matrix, GrSamplerState::Filter* filterMode) {
237 switch (SkMatrixPriv::AdjustHighQualityFilterLevel(matrix)) {
238 case kNone_SkFilterQuality:
239 *filterMode = GrSamplerState::Filter::kNearest;
240 break;
241 case kLow_SkFilterQuality:
242 *filterMode = GrSamplerState::Filter::kBilerp;
243 break;
244 case kMedium_SkFilterQuality:
245 *filterMode = GrSamplerState::Filter::kMipMap;
246 break;
247 case kHigh_SkFilterQuality:
248 // When we use the bicubic filtering effect each sample is read from the texture using
249 // nearest neighbor sampling.
250 *filterMode = GrSamplerState::Filter::kNearest;
251 return true;
252 }
253 return false;
254 }
255