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- /*
- * 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 "include/gpu/GrTexture.h"
- #include "src/gpu/glsl/GrGLSLFragmentShaderBuilder.h"
- #include "src/gpu/glsl/GrGLSLProgramDataManager.h"
- #include "src/gpu/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()));
- uint32_t bidir = bicubicEffect.direction() == GrBicubicEffect::Direction::kXY ? 1 : 0;
- b->add32(bidir | (bicubicEffect.alphaType() << 1));
- }
- protected:
- void onSetData(const GrGLSLProgramDataManager&, const GrFragmentProcessor&) override;
- private:
- typedef GrGLSLProgramDataManager::UniformHandle UniformHandle;
- UniformHandle fDimensions;
- GrTextureDomain::GLDomain fDomain;
- typedef GrGLSLFragmentProcessor INHERITED;
- };
- void GrGLBicubicEffect::emitCode(EmitArgs& args) {
- const GrBicubicEffect& bicubicEffect = args.fFp.cast<GrBicubicEffect>();
- GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
- fDimensions = uniformHandler->addUniform(kFragment_GrShaderFlag, kHalf4_GrSLType, "Dimensions");
- const char* dims = uniformHandler->getUniformCStr(fDimensions);
- 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.xy * float2(0.5);", coords2D.c_str(), dims);
- // 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 dims would cause us to skip/
- // double hit a texel.
- fragBuilder->codeAppendf("half2 f = half2(fract(coord * %s.zw));", dims);
- fragBuilder->codeAppendf("coord = coord + (half2(0.5) - f) * %s.xy;", dims);
- if (bicubicEffect.direction() == GrBicubicEffect::Direction::kXY) {
- 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.xy * float2(%d, %d)", dims, 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;");
- } else {
- // One of the dims.xy values will be zero. So v here selects the nonzero value of f.
- fragBuilder->codeAppend("half v = f.x + f.y;");
- fragBuilder->codeAppend("half v2 = v * v;");
- fragBuilder->codeAppend("half4 w = kMitchellCoefficients * half4(1.0, v, v2, v2 * v);");
- fragBuilder->codeAppend("half4 c[4];");
- for (int i = 0; i < 4; ++i) {
- SkString coord;
- coord.printf("coord + %s.xy * half(%d)", dims, i - 1);
- SkString samplerVar;
- samplerVar.printf("c[%d]", i);
- // With added complexity we could apply the domain once in X or Y depending on
- // direction rather than for each of the four lookups, but then we might not be
- // be able to share code for Direction::kX and ::kY.
- fDomain.sampleTexture(fragBuilder,
- args.fUniformHandler,
- args.fShaderCaps,
- bicubicEffect.domain(),
- samplerVar.c_str(),
- coord,
- args.fTexSamplers[0]);
- }
- 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.
- 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 dims[4] = {0, 0, 0, 0};
- if (bicubicEffect.direction() != GrBicubicEffect::Direction::kY) {
- dims[0] = 1.0f / texture->width();
- dims[2] = texture->width();
- }
- if (bicubicEffect.direction() != GrBicubicEffect::Direction::kX) {
- dims[1] = 1.0f / texture->height();
- dims[3] = texture->height();
- }
- pdman.set4fv(fDimensions, 1, dims);
- 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,
- Direction direction, 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)
- , fDirection(direction) {
- 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)
- , fDirection(that.fDirection) {
- 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 && fDirection == s.fDirection && fAlphaType == s.fAlphaType;
- }
- 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;
- 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;
- }
- return GrBicubicEffect::Make(d->textureProxy(texIdx), SkMatrix::I(), kClampClamp, direction,
- 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;
- }
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