| /* |
| * Copyright 2014 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "GrBicubicEffect.h" |
| |
| #include "GrTexture.h" |
| #include "glsl/GrGLSLFragmentShaderBuilder.h" |
| #include "glsl/GrGLSLProgramDataManager.h" |
| #include "glsl/GrGLSLUniformHandler.h" |
| |
| class GrGLBicubicEffect : public GrGLSLFragmentProcessor { |
| public: |
| void emitCode(EmitArgs&) override; |
| |
| static inline void GenKey(const GrProcessor& effect, const GrShaderCaps&, |
| GrProcessorKeyBuilder* b) { |
| const GrBicubicEffect& bicubicEffect = effect.cast<GrBicubicEffect>(); |
| b->add32(GrTextureDomain::GLDomain::DomainKey(bicubicEffect.domain())); |
| b->add32(bicubicEffect.alphaType()); |
| } |
| |
| protected: |
| void onSetData(const GrGLSLProgramDataManager&, const GrFragmentProcessor&) override; |
| |
| private: |
| typedef GrGLSLProgramDataManager::UniformHandle UniformHandle; |
| |
| UniformHandle fImageIncrementUni; |
| GrTextureDomain::GLDomain fDomain; |
| |
| typedef GrGLSLFragmentProcessor INHERITED; |
| }; |
| |
| void GrGLBicubicEffect::emitCode(EmitArgs& args) { |
| const GrBicubicEffect& bicubicEffect = args.fFp.cast<GrBicubicEffect>(); |
| |
| GrGLSLUniformHandler* uniformHandler = args.fUniformHandler; |
| fImageIncrementUni = uniformHandler->addUniform(kFragment_GrShaderFlag, kHalf2_GrSLType, |
| "ImageIncrement"); |
| |
| const char* imgInc = uniformHandler->getUniformCStr(fImageIncrementUni); |
| |
| GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder; |
| SkString coords2D = fragBuilder->ensureCoords2D(args.fTransformedCoords[0]); |
| |
| /* |
| * Filter weights come from Don Mitchell & Arun Netravali's 'Reconstruction Filters in Computer |
| * Graphics', ACM SIGGRAPH Computer Graphics 22, 4 (Aug. 1988). |
| * ACM DL: http://dl.acm.org/citation.cfm?id=378514 |
| * Free : http://www.cs.utexas.edu/users/fussell/courses/cs384g/lectures/mitchell/Mitchell.pdf |
| * |
| * The authors define a family of cubic filters with two free parameters (B and C): |
| * |
| * { (12 - 9B - 6C)|x|^3 + (-18 + 12B + 6C)|x|^2 + (6 - 2B) if |x| < 1 |
| * k(x) = 1/6 { (-B - 6C)|x|^3 + (6B + 30C)|x|^2 + (-12B - 48C)|x| + (8B + 24C) if 1 <= |x| < 2 |
| * { 0 otherwise |
| * |
| * Various well-known cubic splines can be generated, and the authors select (1/3, 1/3) as their |
| * favorite overall spline - this is now commonly known as the Mitchell filter, and is the |
| * source of the specific weights below. |
| * |
| * This is GLSL, so the matrix is column-major (transposed from standard matrix notation). |
| */ |
| fragBuilder->codeAppend("half4x4 kMitchellCoefficients = half4x4(" |
| " 1.0 / 18.0, 16.0 / 18.0, 1.0 / 18.0, 0.0 / 18.0," |
| "-9.0 / 18.0, 0.0 / 18.0, 9.0 / 18.0, 0.0 / 18.0," |
| "15.0 / 18.0, -36.0 / 18.0, 27.0 / 18.0, -6.0 / 18.0," |
| "-7.0 / 18.0, 21.0 / 18.0, -21.0 / 18.0, 7.0 / 18.0);"); |
| fragBuilder->codeAppendf("float2 coord = %s - %s * float2(0.5);", coords2D.c_str(), imgInc); |
| // We unnormalize the coord in order to determine our fractional offset (f) within the texel |
| // We then snap coord to a texel center and renormalize. The snap prevents cases where the |
| // starting coords are near a texel boundary and accumulations of imgInc would cause us to skip/ |
| // double hit a texel. |
| fragBuilder->codeAppendf("coord /= %s;", imgInc); |
| fragBuilder->codeAppend("half2 f = half2(fract(coord));"); |
| fragBuilder->codeAppendf("coord = (coord - f + half2(0.5)) * %s;", imgInc); |
| fragBuilder->codeAppend("half4 wx = kMitchellCoefficients * half4(1.0, f.x, f.x * f.x, f.x * f.x * f.x);"); |
| fragBuilder->codeAppend("half4 wy = kMitchellCoefficients * half4(1.0, f.y, f.y * f.y, f.y * f.y * f.y);"); |
| fragBuilder->codeAppend("half4 rowColors[4];"); |
| for (int y = 0; y < 4; ++y) { |
| for (int x = 0; x < 4; ++x) { |
| SkString coord; |
| coord.printf("coord + %s * float2(%d, %d)", imgInc, x - 1, y - 1); |
| SkString sampleVar; |
| sampleVar.printf("rowColors[%d]", x); |
| fDomain.sampleTexture(fragBuilder, |
| args.fUniformHandler, |
| args.fShaderCaps, |
| bicubicEffect.domain(), |
| sampleVar.c_str(), |
| coord, |
| args.fTexSamplers[0]); |
| } |
| fragBuilder->codeAppendf( |
| "half4 s%d = wx.x * rowColors[0] + wx.y * rowColors[1] + wx.z * rowColors[2] + wx.w * rowColors[3];", |
| y); |
| } |
| fragBuilder->codeAppend("half4 bicubicColor = wy.x * s0 + wy.y * s1 + wy.z * s2 + wy.w * s3;"); |
| // Bicubic can send colors out of range, so clamp to get them back in (source) gamut. |
| // The kind of clamp we have to do depends on the alpha type. |
| if (kPremul_SkAlphaType == bicubicEffect.alphaType()) { |
| fragBuilder->codeAppend("bicubicColor.a = saturate(bicubicColor.a);"); |
| fragBuilder->codeAppend( |
| "bicubicColor.rgb = max(half3(0.0), min(bicubicColor.rgb, bicubicColor.aaa));"); |
| } else { |
| fragBuilder->codeAppend("bicubicColor = saturate(bicubicColor);"); |
| } |
| fragBuilder->codeAppendf("%s = bicubicColor * %s;", args.fOutputColor, args.fInputColor); |
| } |
| |
| void GrGLBicubicEffect::onSetData(const GrGLSLProgramDataManager& pdman, |
| const GrFragmentProcessor& processor) { |
| const GrBicubicEffect& bicubicEffect = processor.cast<GrBicubicEffect>(); |
| GrTextureProxy* proxy = processor.textureSampler(0).proxy(); |
| GrTexture* texture = proxy->peekTexture(); |
| |
| float imageIncrement[2]; |
| imageIncrement[0] = 1.0f / texture->width(); |
| imageIncrement[1] = 1.0f / texture->height(); |
| pdman.set2fv(fImageIncrementUni, 1, imageIncrement); |
| fDomain.setData(pdman, bicubicEffect.domain(), proxy, |
| processor.textureSampler(0).samplerState()); |
| } |
| |
| GrBicubicEffect::GrBicubicEffect(sk_sp<GrTextureProxy> proxy, |
| const SkMatrix& matrix, const SkRect& domain, |
| const GrSamplerState::WrapMode wrapModes[2], |
| GrTextureDomain::Mode modeX, GrTextureDomain::Mode modeY, |
| SkAlphaType alphaType) |
| : INHERITED{kGrBicubicEffect_ClassID, |
| ModulateForSamplerOptFlags(proxy->config(), |
| GrTextureDomain::IsDecalSampled(wrapModes, modeX,modeY))} |
| , fCoordTransform(matrix, proxy.get()) |
| , fDomain(proxy.get(), domain, modeX, modeY) |
| , fTextureSampler(std::move(proxy), |
| GrSamplerState(wrapModes, GrSamplerState::Filter::kNearest)) |
| , fAlphaType(alphaType) { |
| this->addCoordTransform(&fCoordTransform); |
| this->setTextureSamplerCnt(1); |
| } |
| |
| GrBicubicEffect::GrBicubicEffect(const GrBicubicEffect& that) |
| : INHERITED(kGrBicubicEffect_ClassID, that.optimizationFlags()) |
| , fCoordTransform(that.fCoordTransform) |
| , fDomain(that.fDomain) |
| , fTextureSampler(that.fTextureSampler) |
| , fAlphaType(that.fAlphaType) { |
| this->addCoordTransform(&fCoordTransform); |
| this->setTextureSamplerCnt(1); |
| } |
| |
| void GrBicubicEffect::onGetGLSLProcessorKey(const GrShaderCaps& caps, |
| GrProcessorKeyBuilder* b) const { |
| GrGLBicubicEffect::GenKey(*this, caps, b); |
| } |
| |
| GrGLSLFragmentProcessor* GrBicubicEffect::onCreateGLSLInstance() const { |
| return new GrGLBicubicEffect; |
| } |
| |
| bool GrBicubicEffect::onIsEqual(const GrFragmentProcessor& sBase) const { |
| const GrBicubicEffect& s = sBase.cast<GrBicubicEffect>(); |
| return fDomain == s.fDomain; |
| } |
| |
| GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrBicubicEffect); |
| |
| #if GR_TEST_UTILS |
| std::unique_ptr<GrFragmentProcessor> GrBicubicEffect::TestCreate(GrProcessorTestData* d) { |
| int texIdx = d->fRandom->nextBool() ? GrProcessorUnitTest::kSkiaPMTextureIdx |
| : GrProcessorUnitTest::kAlphaTextureIdx; |
| static const GrSamplerState::WrapMode kClampClamp[] = {GrSamplerState::WrapMode::kClamp, |
| GrSamplerState::WrapMode::kClamp}; |
| SkAlphaType alphaType = d->fRandom->nextBool() ? kPremul_SkAlphaType : kUnpremul_SkAlphaType; |
| return GrBicubicEffect::Make(d->textureProxy(texIdx), SkMatrix::I(), kClampClamp, alphaType); |
| } |
| #endif |
| |
| ////////////////////////////////////////////////////////////////////////////// |
| |
| bool GrBicubicEffect::ShouldUseBicubic(const SkMatrix& matrix, GrSamplerState::Filter* filterMode) { |
| if (matrix.isIdentity()) { |
| *filterMode = GrSamplerState::Filter::kNearest; |
| return false; |
| } |
| |
| SkScalar scales[2]; |
| if (!matrix.getMinMaxScales(scales) || scales[0] < SK_Scalar1) { |
| // Bicubic doesn't handle arbitrary minimization well, as src texels can be skipped |
| // entirely, |
| *filterMode = GrSamplerState::Filter::kMipMap; |
| return false; |
| } |
| // At this point if scales[1] == SK_Scalar1 then the matrix doesn't do any scaling. |
| if (scales[1] == SK_Scalar1) { |
| if (matrix.rectStaysRect() && SkScalarIsInt(matrix.getTranslateX()) && |
| SkScalarIsInt(matrix.getTranslateY())) { |
| *filterMode = GrSamplerState::Filter::kNearest; |
| } else { |
| // Use bilerp to handle rotation or fractional translation. |
| *filterMode = GrSamplerState::Filter::kBilerp; |
| } |
| return false; |
| } |
| // When we use the bicubic filtering effect each sample is read from the texture using |
| // nearest neighbor sampling. |
| *filterMode = GrSamplerState::Filter::kNearest; |
| return true; |
| } |
