| /* |
| * 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 "src/gpu/effects/GrBicubicEffect.h" |
| |
| #include "src/core/SkMatrixPriv.h" |
| #include "src/gpu/GrTexture.h" |
| #include "src/gpu/effects/GrTextureEffect.h" |
| #include "src/gpu/glsl/GrGLSLFragmentShaderBuilder.h" |
| #include "src/gpu/glsl/GrGLSLProgramDataManager.h" |
| #include "src/gpu/glsl/GrGLSLUniformHandler.h" |
| |
| class GrBicubicEffect::Impl : public GrGLSLFragmentProcessor { |
| public: |
| void emitCode(EmitArgs&) override; |
| |
| private: |
| typedef GrGLSLFragmentProcessor INHERITED; |
| }; |
| |
| void GrBicubicEffect::Impl::emitCode(EmitArgs& args) { |
| const GrBicubicEffect& bicubicEffect = args.fFp.cast<GrBicubicEffect>(); |
| |
| GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder; |
| |
| /* |
| * 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 SkSL, 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);"); |
| // We determine our fractional offset (f) within the texel. We then snap coord to a texel |
| // center. The snap prevents cases where the starting coords are near a texel boundary and |
| // offsets with imperfect precision would cause us to skip/double hit a texel. |
| // The use of "texel" above is somewhat abstract as we're sampling a child processor. It is |
| // assumed the child processor represents something akin to a nearest neighbor sampled texture. |
| if (bicubicEffect.fDirection == GrBicubicEffect::Direction::kXY) { |
| fragBuilder->codeAppendf("float2 coord = %s - float2(0.5);", args.fSampleCoord); |
| fragBuilder->codeAppend("half2 f = half2(fract(coord));"); |
| fragBuilder->codeAppend("coord += 0.5 - f;"); |
| 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 + float2(%d, %d)", x - 1, y - 1); |
| auto childStr = |
| this->invokeChild(0, args, SkSL::String(coord.c_str(), coord.size())); |
| fragBuilder->codeAppendf("rowColors[%d] = %s;", x, childStr.c_str()); |
| } |
| 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;"); |
| } else { |
| const char* d = bicubicEffect.fDirection == Direction::kX ? "x" : "y"; |
| fragBuilder->codeAppendf("float coord = %s.%s - 0.5;", args.fSampleCoord, d); |
| fragBuilder->codeAppend("half f = half(fract(coord));"); |
| fragBuilder->codeAppend("coord += 0.5 - f;"); |
| fragBuilder->codeAppend("half f2 = f * f;"); |
| fragBuilder->codeAppend("half4 w = kMitchellCoefficients * half4(1.0, f, f2, f2 * f);"); |
| fragBuilder->codeAppend("half4 c[4];"); |
| for (int i = 0; i < 4; ++i) { |
| SkString coord; |
| if (bicubicEffect.fDirection == Direction::kX) { |
| coord.printf("float2(coord + %d, %s.y)", i - 1, args.fSampleCoord); |
| } else { |
| coord.printf("float2(%s.x, coord + %d)", args.fSampleCoord, i - 1); |
| } |
| auto childStr = this->invokeChild(0, args, SkSL::String(coord.c_str(), coord.size())); |
| fragBuilder->codeAppendf("c[%d] = %s;", i, childStr.c_str()); |
| } |
| fragBuilder->codeAppend( |
| "half4 bicubicColor = c[0] * w.x + c[1] * w.y + c[2] * w.z + c[3] * w.w;"); |
| } |
| // 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. |
| switch (bicubicEffect.fClamp) { |
| case Clamp::kUnpremul: |
| fragBuilder->codeAppend("bicubicColor = saturate(bicubicColor);"); |
| break; |
| case Clamp::kPremul: |
| fragBuilder->codeAppend( |
| "bicubicColor.rgb = max(half3(0.0), min(bicubicColor.rgb, bicubicColor.aaa));"); |
| break; |
| } |
| fragBuilder->codeAppendf("%s = bicubicColor * %s;", args.fOutputColor, args.fInputColor); |
| } |
| |
| std::unique_ptr<GrFragmentProcessor> GrBicubicEffect::Make(GrSurfaceProxyView view, |
| SkAlphaType alphaType, |
| const SkMatrix& matrix, |
| Direction direction) { |
| auto fp = GrTextureEffect::Make(std::move(view), alphaType, SkMatrix::I()); |
| auto clamp = kPremul_SkAlphaType == alphaType ? Clamp::kPremul : Clamp::kUnpremul; |
| return std::unique_ptr<GrFragmentProcessor>( |
| new GrBicubicEffect(std::move(fp), matrix, direction, clamp)); |
| } |
| |
| std::unique_ptr<GrFragmentProcessor> GrBicubicEffect::Make(GrSurfaceProxyView view, |
| SkAlphaType alphaType, |
| const SkMatrix& matrix, |
| const GrSamplerState::WrapMode wrapX, |
| const GrSamplerState::WrapMode wrapY, |
| Direction direction, |
| const GrCaps& caps) { |
| GrSamplerState sampler(wrapX, wrapY, GrSamplerState::Filter::kNearest); |
| std::unique_ptr<GrFragmentProcessor> fp; |
| fp = GrTextureEffect::Make(std::move(view), alphaType, SkMatrix::I(), sampler, caps); |
| auto clamp = kPremul_SkAlphaType == alphaType ? Clamp::kPremul : Clamp::kUnpremul; |
| return std::unique_ptr<GrFragmentProcessor>( |
| new GrBicubicEffect(std::move(fp), matrix, direction, clamp)); |
| } |
| |
| std::unique_ptr<GrFragmentProcessor> GrBicubicEffect::MakeSubset( |
| GrSurfaceProxyView view, |
| SkAlphaType alphaType, |
| const SkMatrix& matrix, |
| const GrSamplerState::WrapMode wrapX, |
| const GrSamplerState::WrapMode wrapY, |
| const SkRect& subset, |
| Direction direction, |
| const GrCaps& caps) { |
| GrSamplerState sampler(wrapX, wrapY, GrSamplerState::Filter::kNearest); |
| std::unique_ptr<GrFragmentProcessor> fp; |
| fp = GrTextureEffect::MakeSubset( |
| std::move(view), alphaType, SkMatrix::I(), sampler, subset, caps); |
| auto clamp = kPremul_SkAlphaType == alphaType ? Clamp::kPremul : Clamp::kUnpremul; |
| return std::unique_ptr<GrFragmentProcessor>( |
| new GrBicubicEffect(std::move(fp), matrix, direction, clamp)); |
| } |
| |
| std::unique_ptr<GrFragmentProcessor> GrBicubicEffect::Make(std::unique_ptr<GrFragmentProcessor> fp, |
| SkAlphaType alphaType, |
| const SkMatrix& matrix, |
| Direction direction) { |
| auto clamp = kPremul_SkAlphaType == alphaType ? Clamp::kPremul : Clamp::kUnpremul; |
| return std::unique_ptr<GrFragmentProcessor>( |
| new GrBicubicEffect(std::move(fp), matrix, direction, clamp)); |
| } |
| |
| GrBicubicEffect::GrBicubicEffect(std::unique_ptr<GrFragmentProcessor> fp, |
| const SkMatrix& matrix, |
| Direction direction, |
| Clamp clamp) |
| : INHERITED(kGrBicubicEffect_ClassID, ProcessorOptimizationFlags(fp.get())) |
| , fCoordTransform(matrix) |
| , fDirection(direction) |
| , fClamp(clamp) { |
| this->addCoordTransform(&fCoordTransform); |
| this->registerExplicitlySampledChild(std::move(fp)); |
| } |
| |
| GrBicubicEffect::GrBicubicEffect(const GrBicubicEffect& that) |
| : INHERITED(kGrBicubicEffect_ClassID, that.optimizationFlags()) |
| , fCoordTransform(that.fCoordTransform) |
| , fDirection(that.fDirection) |
| , fClamp(that.fClamp) { |
| this->addCoordTransform(&fCoordTransform); |
| this->cloneAndRegisterAllChildProcessors(that); |
| } |
| |
| void GrBicubicEffect::onGetGLSLProcessorKey(const GrShaderCaps& caps, |
| GrProcessorKeyBuilder* b) const { |
| uint32_t key = static_cast<uint32_t>(fDirection) | (static_cast<uint32_t>(fClamp) << 2); |
| b->add32(key); |
| } |
| |
| GrGLSLFragmentProcessor* GrBicubicEffect::onCreateGLSLInstance() const { return new Impl(); } |
| |
| bool GrBicubicEffect::onIsEqual(const GrFragmentProcessor& other) const { |
| const auto& that = other.cast<GrBicubicEffect>(); |
| return fDirection == that.fDirection && fClamp == that.fClamp; |
| } |
| |
| SkPMColor4f GrBicubicEffect::constantOutputForConstantInput(const SkPMColor4f& input) const { |
| return GrFragmentProcessor::ConstantOutputForConstantInput(this->childProcessor(0), input); |
| } |
| |
| GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrBicubicEffect); |
| |
| #if GR_TEST_UTILS |
| std::unique_ptr<GrFragmentProcessor> GrBicubicEffect::TestCreate(GrProcessorTestData* d) { |
| Direction direction = Direction::kX; |
| switch (d->fRandom->nextULessThan(3)) { |
| case 0: |
| direction = Direction::kX; |
| break; |
| case 1: |
| direction = Direction::kY; |
| break; |
| case 2: |
| direction = Direction::kXY; |
| break; |
| } |
| auto m = GrTest::TestMatrix(d->fRandom); |
| switch (d->fRandom->nextULessThan(3)) { |
| case 0: { |
| auto [view, ct, at] = d->randomView(); |
| GrSamplerState::WrapMode wm[2]; |
| GrTest::TestWrapModes(d->fRandom, wm); |
| |
| if (d->fRandom->nextBool()) { |
| SkRect subset; |
| subset.fLeft = d->fRandom->nextSScalar1() * view.width(); |
| subset.fTop = d->fRandom->nextSScalar1() * view.height(); |
| subset.fRight = d->fRandom->nextSScalar1() * view.width(); |
| subset.fBottom = d->fRandom->nextSScalar1() * view.height(); |
| subset.sort(); |
| return MakeSubset( |
| std::move(view), at, m, wm[0], wm[1], subset, direction, *d->caps()); |
| } |
| return Make(std::move(view), at, m, wm[0], wm[1], direction, *d->caps()); |
| } |
| case 1: { |
| auto [view, ct, at] = d->randomView(); |
| return Make(std::move(view), at, m, direction); |
| } |
| default: { |
| SkAlphaType at; |
| do { |
| at = static_cast<SkAlphaType>(d->fRandom->nextULessThan(kLastEnum_SkAlphaType + 1)); |
| } while (at != kUnknown_SkAlphaType); |
| std::unique_ptr<GrFragmentProcessor> fp; |
| // We have a restriction that explicit coords only work for FPs with zero or one |
| // coord transform. |
| do { |
| fp = GrProcessorUnitTest::MakeChildFP(d); |
| } while (fp->numCoordTransforms() > 1); |
| return Make(std::move(fp), at, m, direction); |
| } |
| } |
| } |
| #endif |
| |
| ////////////////////////////////////////////////////////////////////////////// |
| |
| bool GrBicubicEffect::ShouldUseBicubic(const SkMatrix& matrix, GrSamplerState::Filter* filterMode) { |
| switch (SkMatrixPriv::AdjustHighQualityFilterLevel(matrix)) { |
| case kNone_SkFilterQuality: |
| *filterMode = GrSamplerState::Filter::kNearest; |
| break; |
| case kLow_SkFilterQuality: |
| *filterMode = GrSamplerState::Filter::kBilerp; |
| break; |
| case kMedium_SkFilterQuality: |
| *filterMode = GrSamplerState::Filter::kMipMap; |
| break; |
| case kHigh_SkFilterQuality: |
| // When we use the bicubic filtering effect each sample is read from the texture using |
| // nearest neighbor sampling. |
| *filterMode = GrSamplerState::Filter::kNearest; |
| return true; |
| } |
| return false; |
| } |