src/gpu/effects/GrMatrixConvolutionEffect.cpp - platform/external/skia - Gitiles

 /*
  * 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/GrMatrixConvolutionEffect.h"

 #include "src/gpu/GrTexture.h"
 #include "src/gpu/GrTextureProxy.h"
 #include "src/gpu/effects/GrTextureEffect.h"
 #include "src/gpu/glsl/GrGLSLFragmentProcessor.h"
 #include "src/gpu/glsl/GrGLSLFragmentShaderBuilder.h"
 #include "src/gpu/glsl/GrGLSLProgramDataManager.h"
 #include "src/gpu/glsl/GrGLSLUniformHandler.h"

 class GrGLMatrixConvolutionEffect : public GrGLSLFragmentProcessor {
 public:
     void emitCode(EmitArgs&) override;

     static inline void GenKey(const GrProcessor&, const GrShaderCaps&, GrProcessorKeyBuilder*);

 protected:
     void onSetData(const GrGLSLProgramDataManager&, const GrFragmentProcessor&) override;

 private:
     typedef GrGLSLProgramDataManager::UniformHandle UniformHandle;

     UniformHandle               fKernelUni;
     UniformHandle               fKernelOffsetUni;
     UniformHandle               fGainUni;
     UniformHandle               fBiasUni;

     typedef GrGLSLFragmentProcessor INHERITED;
 };

 void GrGLMatrixConvolutionEffect::emitCode(EmitArgs& args) {
     const GrMatrixConvolutionEffect& mce = args.fFp.cast<GrMatrixConvolutionEffect>();

     int kWidth = mce.kernelSize().width();
     int kHeight = mce.kernelSize().height();

     int arrayCount = (kWidth * kHeight + 3) / 4;
     SkASSERT(4 * arrayCount >= kWidth * kHeight);

     GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
     fKernelUni = uniformHandler->addUniformArray(&mce, kFragment_GrShaderFlag, kHalf4_GrSLType,
                                                  "Kernel",
                                                  arrayCount);
     fKernelOffsetUni = uniformHandler->addUniform(&mce, kFragment_GrShaderFlag, kHalf2_GrSLType,
                                                   "KernelOffset");
     fGainUni = uniformHandler->addUniform(&mce, kFragment_GrShaderFlag, kHalf_GrSLType, "Gain");
     fBiasUni = uniformHandler->addUniform(&mce, kFragment_GrShaderFlag, kHalf_GrSLType, "Bias");

     const char* kernelOffset = uniformHandler->getUniformCStr(fKernelOffsetUni);
     const char* kernel = uniformHandler->getUniformCStr(fKernelUni);
     const char* gain = uniformHandler->getUniformCStr(fGainUni);
     const char* bias = uniformHandler->getUniformCStr(fBiasUni);

     GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
     SkString coords2D = fragBuilder->ensureCoords2D(args.fTransformedCoords[0].fVaryingPoint,
                                                     mce.sampleMatrix());
     fragBuilder->codeAppend("half4 sum = half4(0, 0, 0, 0);");
     fragBuilder->codeAppendf("float2 coord = %s - %s;", coords2D.c_str(), kernelOffset);
     fragBuilder->codeAppend("half4 c;");

     const char* kVecSuffix[4] = { ".x", ".y", ".z", ".w" };
     for (int y = 0; y < kHeight; y++) {
         for (int x = 0; x < kWidth; x++) {
             GrGLSLShaderBuilder::ShaderBlock block(fragBuilder);
             int offset = y*kWidth + x;

             fragBuilder->codeAppendf("half k = %s[%d]%s;", kernel, offset / 4,
                                      kVecSuffix[offset & 0x3]);
             SkSL::String coord;
             coord.appendf("coord + half2(%d, %d)", x, y);
             auto sample = this->invokeChild(0, args, coord);
             fragBuilder->codeAppendf("half4 c = %s;", sample.c_str());
             if (!mce.convolveAlpha()) {
                 fragBuilder->codeAppend("c.rgb /= c.a;");
                 fragBuilder->codeAppend("c.rgb = saturate(c.rgb);");
             }
             fragBuilder->codeAppend("sum += c * k;");
         }
     }
     if (mce.convolveAlpha()) {
         fragBuilder->codeAppendf("%s = sum * %s + %s;", args.fOutputColor, gain, bias);
         fragBuilder->codeAppendf("%s.a = saturate(%s.a);", args.fOutputColor, args.fOutputColor);
         fragBuilder->codeAppendf("%s.rgb = clamp(%s.rgb, 0.0, %s.a);",
                                  args.fOutputColor, args.fOutputColor, args.fOutputColor);
     } else {
         auto sample = this->invokeChild(0, args, coords2D.c_str());
         fragBuilder->codeAppendf("c = %s;", sample.c_str());
         fragBuilder->codeAppendf("%s.a = c.a;", args.fOutputColor);
         fragBuilder->codeAppendf("%s.rgb = saturate(sum.rgb * %s + %s);", args.fOutputColor, gain, bias);
         fragBuilder->codeAppendf("%s.rgb *= %s.a;", args.fOutputColor, args.fOutputColor);
     }
     fragBuilder->codeAppendf("%s *= %s;\n", args.fOutputColor, args.fInputColor);
 }

 void GrGLMatrixConvolutionEffect::GenKey(const GrProcessor& processor,
                                          const GrShaderCaps&, GrProcessorKeyBuilder* b) {
     const GrMatrixConvolutionEffect& m = processor.cast<GrMatrixConvolutionEffect>();
     SkASSERT(m.kernelSize().width() <= 0x7FFF && m.kernelSize().height() <= 0xFFFF);
     uint32_t key = m.kernelSize().width() << 16 | m.kernelSize().height();
     key |= m.convolveAlpha() ? 1U << 31 : 0;
     b->add32(key);
 }

 void GrGLMatrixConvolutionEffect::onSetData(const GrGLSLProgramDataManager& pdman,
                                             const GrFragmentProcessor& processor) {
     const GrMatrixConvolutionEffect& conv = processor.cast<GrMatrixConvolutionEffect>();
     pdman.set2fv(fKernelOffsetUni, 1, conv.kernelOffset().ptr());
     int kernelCount = conv.kernelSize().width() * conv.kernelSize().height();
     int arrayCount = (kernelCount + 3) / 4;
     SkASSERT(4 * arrayCount >= kernelCount);
     pdman.set4fv(fKernelUni, arrayCount, conv.kernel());
     pdman.set1f(fGainUni, conv.gain());
     pdman.set1f(fBiasUni, conv.bias());
 }

 GrMatrixConvolutionEffect::GrMatrixConvolutionEffect(std::unique_ptr<GrFragmentProcessor> child,
                                                      const SkISize& kernelSize,
                                                      const SkScalar* kernel,
                                                      SkScalar gain,
                                                      SkScalar bias,
                                                      const SkIPoint& kernelOffset,
                                                      bool convolveAlpha)
         // To advertise either the modulation or opaqueness optimizations we'd have to examine the
         // parameters.
         : INHERITED(kGrMatrixConvolutionEffect_ClassID, kNone_OptimizationFlags)
         , fKernelSize(kernelSize)
         , fGain(SkScalarToFloat(gain))
         , fBias(SkScalarToFloat(bias) / 255.0f)
         , fConvolveAlpha(convolveAlpha) {
     child->setSampledWithExplicitCoords();
     this->registerChildProcessor(std::move(child));
     for (int i = 0; i < kernelSize.width() * kernelSize.height(); i++) {
         fKernel[i] = SkScalarToFloat(kernel[i]);
     }
     fKernelOffset = {static_cast<float>(kernelOffset.x()),
                      static_cast<float>(kernelOffset.y())};
     this->addCoordTransform(&fCoordTransform);
 }

 GrMatrixConvolutionEffect::GrMatrixConvolutionEffect(const GrMatrixConvolutionEffect& that)
         : INHERITED(kGrMatrixConvolutionEffect_ClassID, kNone_OptimizationFlags)
         , fKernelSize(that.fKernelSize)
         , fGain(that.fGain)
         , fBias(that.fBias)
         , fKernelOffset(that.fKernelOffset)
         , fConvolveAlpha(that.fConvolveAlpha) {
     auto child = that.childProcessor(0).clone();
     child->setSampledWithExplicitCoords();
     this->registerChildProcessor(std::move(child));
     std::copy_n(that.fKernel, fKernelSize.width() * fKernelSize.height(), fKernel);
     this->addCoordTransform(&fCoordTransform);
 }

 std::unique_ptr<GrFragmentProcessor> GrMatrixConvolutionEffect::clone() const {
     return std::unique_ptr<GrFragmentProcessor>(new GrMatrixConvolutionEffect(*this));
 }

 void GrMatrixConvolutionEffect::onGetGLSLProcessorKey(const GrShaderCaps& caps,
                                                       GrProcessorKeyBuilder* b) const {
     GrGLMatrixConvolutionEffect::GenKey(*this, caps, b);
 }

 GrGLSLFragmentProcessor* GrMatrixConvolutionEffect::onCreateGLSLInstance() const  {
     return new GrGLMatrixConvolutionEffect;
 }

 bool GrMatrixConvolutionEffect::onIsEqual(const GrFragmentProcessor& sBase) const {
     const GrMatrixConvolutionEffect& s = sBase.cast<GrMatrixConvolutionEffect>();
     return fKernelSize == s.kernelSize() &&
            std::equal(fKernel, fKernel + fKernelSize.area(), s.fKernel) &&
            fGain == s.gain() &&
            fBias == s.bias() &&
            fKernelOffset == s.kernelOffset() &&
            fConvolveAlpha == s.convolveAlpha();
 }

 static void fill_in_1D_gaussian_kernel_with_stride(float* kernel, int size, int stride,
                                                    float twoSigmaSqrd) {
     SkASSERT(!SkScalarNearlyZero(twoSigmaSqrd, SK_ScalarNearlyZero));

     const float sigmaDenom = 1.0f / twoSigmaSqrd;
     const int radius = size / 2;

     float sum = 0.0f;
     for (int i = 0; i < size; ++i) {
         float term = static_cast<float>(i - radius);
         // Note that the constant term (1/(sqrt(2*pi*sigma^2)) of the Gaussian
         // is dropped here, since we renormalize the kernel below.
         kernel[i * stride] = sk_float_exp(-term * term * sigmaDenom);
         sum += kernel[i * stride];
     }
     // Normalize the kernel
     float scale = 1.0f / sum;
     for (int i = 0; i < size; ++i) {
         kernel[i * stride] *= scale;
     }
 }

 static void fill_in_2D_gaussian_kernel(float* kernel, int width, int height,
                                        SkScalar sigmaX, SkScalar sigmaY) {
     SkASSERT(width * height <= MAX_KERNEL_SIZE);
     const float twoSigmaSqrdX = 2.0f * SkScalarToFloat(SkScalarSquare(sigmaX));
     const float twoSigmaSqrdY = 2.0f * SkScalarToFloat(SkScalarSquare(sigmaY));

     // TODO: in all of these degenerate cases we're uploading (and using) a whole lot of zeros.
     if (SkScalarNearlyZero(twoSigmaSqrdX, SK_ScalarNearlyZero) ||
         SkScalarNearlyZero(twoSigmaSqrdY, SK_ScalarNearlyZero)) {
         // In this case the 2D Gaussian degenerates to a 1D Gaussian (in X or Y) or a point
         SkASSERT(3 == width || 3 == height);
         std::fill_n(kernel, width*height, 0);

         if (SkScalarNearlyZero(twoSigmaSqrdX, SK_ScalarNearlyZero) &&
             SkScalarNearlyZero(twoSigmaSqrdY, SK_ScalarNearlyZero)) {
             // A point
             SkASSERT(3 == width && 3 == height);
             kernel[4] = 1.0f;
         } else if (SkScalarNearlyZero(twoSigmaSqrdX, SK_ScalarNearlyZero)) {
             // A 1D Gaussian in Y
             SkASSERT(3 == width);
             // Down the middle column of the kernel with a stride of width
             fill_in_1D_gaussian_kernel_with_stride(&kernel[1], height, width, twoSigmaSqrdY);
         } else {
             // A 1D Gaussian in X
             SkASSERT(SkScalarNearlyZero(twoSigmaSqrdY, SK_ScalarNearlyZero));
             SkASSERT(3 == height);
             // Down the middle row of the kernel with a stride of 1
             fill_in_1D_gaussian_kernel_with_stride(&kernel[width], width, 1, twoSigmaSqrdX);
         }
         return;
     }

     const float sigmaXDenom = 1.0f / twoSigmaSqrdX;
     const float sigmaYDenom = 1.0f / twoSigmaSqrdY;
     const int xRadius = width / 2;
     const int yRadius = height / 2;

     float sum = 0.0f;
     for (int x = 0; x < width; x++) {
         float xTerm = static_cast<float>(x - xRadius);
         xTerm = xTerm * xTerm * sigmaXDenom;
         for (int y = 0; y < height; y++) {
             float yTerm = static_cast<float>(y - yRadius);
             float xyTerm = sk_float_exp(-(xTerm + yTerm * yTerm * sigmaYDenom));
             // Note that the constant term (1/(sqrt(2*pi*sigma^2)) of the Gaussian
             // is dropped here, since we renormalize the kernel below.
             kernel[y * width + x] = xyTerm;
             sum += xyTerm;
         }
     }
     // Normalize the kernel
     float scale = 1.0f / sum;
     for (int i = 0; i < width * height; ++i) {
         kernel[i] *= scale;
     }
 }

 std::unique_ptr<GrFragmentProcessor> GrMatrixConvolutionEffect::Make(GrSurfaceProxyView srcView,
                                                                      const SkIRect& srcBounds,
                                                                      const SkISize& kernelSize,
                                                                      const SkScalar* kernel,
                                                                      SkScalar gain,
                                                                      SkScalar bias,
                                                                      const SkIPoint& kernelOffset,
                                                                      GrSamplerState::WrapMode wm,
                                                                      bool convolveAlpha,
                                                                      const GrCaps& caps) {
     GrSamplerState sampler(wm, GrSamplerState::Filter::kNearest);
     auto child = GrTextureEffect::MakeSubset(std::move(srcView), kPremul_SkAlphaType, SkMatrix::I(),
                                              sampler, SkRect::Make(srcBounds), caps);
     return std::unique_ptr<GrFragmentProcessor>(new GrMatrixConvolutionEffect(
             std::move(child), kernelSize, kernel, gain, bias, kernelOffset, convolveAlpha));
 }

 std::unique_ptr<GrFragmentProcessor> GrMatrixConvolutionEffect::MakeGaussian(
         GrSurfaceProxyView srcView,
         const SkIRect& srcBounds,
         const SkISize& kernelSize,
         SkScalar gain,
         SkScalar bias,
         const SkIPoint& kernelOffset,
         GrSamplerState::WrapMode wm,
         bool convolveAlpha,
         SkScalar sigmaX,
         SkScalar sigmaY,
         const GrCaps& caps) {
     float kernel[MAX_KERNEL_SIZE];

     fill_in_2D_gaussian_kernel(kernel, kernelSize.width(), kernelSize.height(), sigmaX, sigmaY);
     return Make(std::move(srcView), srcBounds, kernelSize, kernel, gain, bias, kernelOffset, wm,
                 convolveAlpha, caps);
 }

 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrMatrixConvolutionEffect);

 #if GR_TEST_UTILS
 std::unique_ptr<GrFragmentProcessor> GrMatrixConvolutionEffect::TestCreate(GrProcessorTestData* d) {
     auto [view, ct, at] = d->randomView();

     int width = d->fRandom->nextRangeU(1, MAX_KERNEL_SIZE);
     int height = d->fRandom->nextRangeU(1, MAX_KERNEL_SIZE / width);
     SkISize kernelSize = SkISize::Make(width, height);
     std::unique_ptr<SkScalar[]> kernel(new SkScalar[width * height]);
     for (int i = 0; i < width * height; i++) {
         kernel.get()[i] = d->fRandom->nextSScalar1();
     }
     SkScalar gain = d->fRandom->nextSScalar1();
     SkScalar bias = d->fRandom->nextSScalar1();

     uint32_t kernalOffsetX = d->fRandom->nextRangeU(0, kernelSize.width());
     uint32_t kernalOffsetY = d->fRandom->nextRangeU(0, kernelSize.height());
     SkIPoint kernelOffset = SkIPoint::Make(kernalOffsetX, kernalOffsetY);

     uint32_t boundsX = d->fRandom->nextRangeU(0, view.width());
     uint32_t boundsY = d->fRandom->nextRangeU(0, view.height());
     uint32_t boundsW = d->fRandom->nextRangeU(0, view.width());
     uint32_t boundsH = d->fRandom->nextRangeU(0, view.height());
     SkIRect bounds = SkIRect::MakeXYWH(boundsX, boundsY, boundsW, boundsH);

     auto wm = static_cast<GrSamplerState::WrapMode>(
             d->fRandom->nextULessThan(GrSamplerState::kWrapModeCount));
     bool convolveAlpha = d->fRandom->nextBool();

     return GrMatrixConvolutionEffect::Make(std::move(view),
                                            bounds,
                                            kernelSize,
                                            kernel.get(),
                                            gain,
                                            bias,
                                            kernelOffset,
                                            wm,
                                            convolveAlpha,
                                            *d->caps());
 }
 #endif
	/*
	* 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/GrMatrixConvolutionEffect.h"

	#include "src/gpu/GrTexture.h"
	#include "src/gpu/GrTextureProxy.h"
	#include "src/gpu/effects/GrTextureEffect.h"
	#include "src/gpu/glsl/GrGLSLFragmentProcessor.h"
	#include "src/gpu/glsl/GrGLSLFragmentShaderBuilder.h"
	#include "src/gpu/glsl/GrGLSLProgramDataManager.h"
	#include "src/gpu/glsl/GrGLSLUniformHandler.h"

	class GrGLMatrixConvolutionEffect : public GrGLSLFragmentProcessor {
	public:
	void emitCode(EmitArgs&) override;

	static inline void GenKey(const GrProcessor&, const GrShaderCaps&, GrProcessorKeyBuilder*);

	protected:
	void onSetData(const GrGLSLProgramDataManager&, const GrFragmentProcessor&) override;

	private:
	typedef GrGLSLProgramDataManager::UniformHandle UniformHandle;

	UniformHandle fKernelUni;
	UniformHandle fKernelOffsetUni;
	UniformHandle fGainUni;
	UniformHandle fBiasUni;

	typedef GrGLSLFragmentProcessor INHERITED;
	};

	void GrGLMatrixConvolutionEffect::emitCode(EmitArgs& args) {
	const GrMatrixConvolutionEffect& mce = args.fFp.cast<GrMatrixConvolutionEffect>();

	int kWidth = mce.kernelSize().width();
	int kHeight = mce.kernelSize().height();

	int arrayCount = (kWidth * kHeight + 3) / 4;
	SkASSERT(4 * arrayCount >= kWidth * kHeight);

	GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
	fKernelUni = uniformHandler->addUniformArray(&mce, kFragment_GrShaderFlag, kHalf4_GrSLType,
	"Kernel",
	arrayCount);
	fKernelOffsetUni = uniformHandler->addUniform(&mce, kFragment_GrShaderFlag, kHalf2_GrSLType,
	"KernelOffset");
	fGainUni = uniformHandler->addUniform(&mce, kFragment_GrShaderFlag, kHalf_GrSLType, "Gain");
	fBiasUni = uniformHandler->addUniform(&mce, kFragment_GrShaderFlag, kHalf_GrSLType, "Bias");

	const char* kernelOffset = uniformHandler->getUniformCStr(fKernelOffsetUni);
	const char* kernel = uniformHandler->getUniformCStr(fKernelUni);
	const char* gain = uniformHandler->getUniformCStr(fGainUni);
	const char* bias = uniformHandler->getUniformCStr(fBiasUni);

	GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
	SkString coords2D = fragBuilder->ensureCoords2D(args.fTransformedCoords[0].fVaryingPoint,
	mce.sampleMatrix());
	fragBuilder->codeAppend("half4 sum = half4(0, 0, 0, 0);");
	fragBuilder->codeAppendf("float2 coord = %s - %s;", coords2D.c_str(), kernelOffset);
	fragBuilder->codeAppend("half4 c;");

	const char* kVecSuffix[4] = { ".x", ".y", ".z", ".w" };
	for (int y = 0; y < kHeight; y++) {
	for (int x = 0; x < kWidth; x++) {
	GrGLSLShaderBuilder::ShaderBlock block(fragBuilder);
	int offset = y*kWidth + x;

	fragBuilder->codeAppendf("half k = %s[%d]%s;", kernel, offset / 4,
	kVecSuffix[offset & 0x3]);
	SkSL::String coord;
	coord.appendf("coord + half2(%d, %d)", x, y);
	auto sample = this->invokeChild(0, args, coord);
	fragBuilder->codeAppendf("half4 c = %s;", sample.c_str());
	if (!mce.convolveAlpha()) {
	fragBuilder->codeAppend("c.rgb /= c.a;");
	fragBuilder->codeAppend("c.rgb = saturate(c.rgb);");
	}
	fragBuilder->codeAppend("sum += c * k;");
	}
	}
	if (mce.convolveAlpha()) {
	fragBuilder->codeAppendf("%s = sum * %s + %s;", args.fOutputColor, gain, bias);
	fragBuilder->codeAppendf("%s.a = saturate(%s.a);", args.fOutputColor, args.fOutputColor);
	fragBuilder->codeAppendf("%s.rgb = clamp(%s.rgb, 0.0, %s.a);",
	args.fOutputColor, args.fOutputColor, args.fOutputColor);
	} else {
	auto sample = this->invokeChild(0, args, coords2D.c_str());
	fragBuilder->codeAppendf("c = %s;", sample.c_str());
	fragBuilder->codeAppendf("%s.a = c.a;", args.fOutputColor);
	fragBuilder->codeAppendf("%s.rgb = saturate(sum.rgb * %s + %s);", args.fOutputColor, gain, bias);
	fragBuilder->codeAppendf("%s.rgb *= %s.a;", args.fOutputColor, args.fOutputColor);
	}
	fragBuilder->codeAppendf("%s *= %s;\n", args.fOutputColor, args.fInputColor);
	}

	void GrGLMatrixConvolutionEffect::GenKey(const GrProcessor& processor,
	const GrShaderCaps&, GrProcessorKeyBuilder* b) {
	const GrMatrixConvolutionEffect& m = processor.cast<GrMatrixConvolutionEffect>();
	SkASSERT(m.kernelSize().width() <= 0x7FFF && m.kernelSize().height() <= 0xFFFF);
	uint32_t key = m.kernelSize().width() << 16 \| m.kernelSize().height();
	key \|= m.convolveAlpha() ? 1U << 31 : 0;
	b->add32(key);
	}

	void GrGLMatrixConvolutionEffect::onSetData(const GrGLSLProgramDataManager& pdman,
	const GrFragmentProcessor& processor) {
	const GrMatrixConvolutionEffect& conv = processor.cast<GrMatrixConvolutionEffect>();
	pdman.set2fv(fKernelOffsetUni, 1, conv.kernelOffset().ptr());
	int kernelCount = conv.kernelSize().width() * conv.kernelSize().height();
	int arrayCount = (kernelCount + 3) / 4;
	SkASSERT(4 * arrayCount >= kernelCount);
	pdman.set4fv(fKernelUni, arrayCount, conv.kernel());
	pdman.set1f(fGainUni, conv.gain());
	pdman.set1f(fBiasUni, conv.bias());
	}

	GrMatrixConvolutionEffect::GrMatrixConvolutionEffect(std::unique_ptr<GrFragmentProcessor> child,
	const SkISize& kernelSize,
	const SkScalar* kernel,
	SkScalar gain,
	SkScalar bias,
	const SkIPoint& kernelOffset,
	bool convolveAlpha)
	// To advertise either the modulation or opaqueness optimizations we'd have to examine the
	// parameters.
	: INHERITED(kGrMatrixConvolutionEffect_ClassID, kNone_OptimizationFlags)
	, fKernelSize(kernelSize)
	, fGain(SkScalarToFloat(gain))
	, fBias(SkScalarToFloat(bias) / 255.0f)
	, fConvolveAlpha(convolveAlpha) {
	child->setSampledWithExplicitCoords();
	this->registerChildProcessor(std::move(child));
	for (int i = 0; i < kernelSize.width() * kernelSize.height(); i++) {
	fKernel[i] = SkScalarToFloat(kernel[i]);
	}
	fKernelOffset = {static_cast<float>(kernelOffset.x()),
	static_cast<float>(kernelOffset.y())};
	this->addCoordTransform(&fCoordTransform);
	}

	GrMatrixConvolutionEffect::GrMatrixConvolutionEffect(const GrMatrixConvolutionEffect& that)
	: INHERITED(kGrMatrixConvolutionEffect_ClassID, kNone_OptimizationFlags)
	, fKernelSize(that.fKernelSize)
	, fGain(that.fGain)
	, fBias(that.fBias)
	, fKernelOffset(that.fKernelOffset)
	, fConvolveAlpha(that.fConvolveAlpha) {
	auto child = that.childProcessor(0).clone();
	child->setSampledWithExplicitCoords();
	this->registerChildProcessor(std::move(child));
	std::copy_n(that.fKernel, fKernelSize.width() * fKernelSize.height(), fKernel);
	this->addCoordTransform(&fCoordTransform);
	}

	std::unique_ptr<GrFragmentProcessor> GrMatrixConvolutionEffect::clone() const {
	return std::unique_ptr<GrFragmentProcessor>(new GrMatrixConvolutionEffect(*this));
	}

	void GrMatrixConvolutionEffect::onGetGLSLProcessorKey(const GrShaderCaps& caps,
	GrProcessorKeyBuilder* b) const {
	GrGLMatrixConvolutionEffect::GenKey(*this, caps, b);
	}

	GrGLSLFragmentProcessor* GrMatrixConvolutionEffect::onCreateGLSLInstance() const {
	return new GrGLMatrixConvolutionEffect;
	}

	bool GrMatrixConvolutionEffect::onIsEqual(const GrFragmentProcessor& sBase) const {
	const GrMatrixConvolutionEffect& s = sBase.cast<GrMatrixConvolutionEffect>();
	return fKernelSize == s.kernelSize() &&
	std::equal(fKernel, fKernel + fKernelSize.area(), s.fKernel) &&
	fGain == s.gain() &&
	fBias == s.bias() &&
	fKernelOffset == s.kernelOffset() &&
	fConvolveAlpha == s.convolveAlpha();
	}

	static void fill_in_1D_gaussian_kernel_with_stride(float* kernel, int size, int stride,
	float twoSigmaSqrd) {
	SkASSERT(!SkScalarNearlyZero(twoSigmaSqrd, SK_ScalarNearlyZero));

	const float sigmaDenom = 1.0f / twoSigmaSqrd;
	const int radius = size / 2;

	float sum = 0.0f;
	for (int i = 0; i < size; ++i) {
	float term = static_cast<float>(i - radius);
	// Note that the constant term (1/(sqrt(2pisigma^2)) of the Gaussian
	// is dropped here, since we renormalize the kernel below.
	kernel[i * stride] = sk_float_exp(-term * term * sigmaDenom);
	sum += kernel[i * stride];
	}
	// Normalize the kernel
	float scale = 1.0f / sum;
	for (int i = 0; i < size; ++i) {
	kernel[i * stride] *= scale;
	}
	}

	static void fill_in_2D_gaussian_kernel(float* kernel, int width, int height,
	SkScalar sigmaX, SkScalar sigmaY) {
	SkASSERT(width * height <= MAX_KERNEL_SIZE);
	const float twoSigmaSqrdX = 2.0f * SkScalarToFloat(SkScalarSquare(sigmaX));
	const float twoSigmaSqrdY = 2.0f * SkScalarToFloat(SkScalarSquare(sigmaY));

	// TODO: in all of these degenerate cases we're uploading (and using) a whole lot of zeros.
	if (SkScalarNearlyZero(twoSigmaSqrdX, SK_ScalarNearlyZero) \|\|
	SkScalarNearlyZero(twoSigmaSqrdY, SK_ScalarNearlyZero)) {
	// In this case the 2D Gaussian degenerates to a 1D Gaussian (in X or Y) or a point
	SkASSERT(3 == width \|\| 3 == height);
	std::fill_n(kernel, width*height, 0);

	if (SkScalarNearlyZero(twoSigmaSqrdX, SK_ScalarNearlyZero) &&
	SkScalarNearlyZero(twoSigmaSqrdY, SK_ScalarNearlyZero)) {
	// A point
	SkASSERT(3 == width && 3 == height);
	kernel[4] = 1.0f;
	} else if (SkScalarNearlyZero(twoSigmaSqrdX, SK_ScalarNearlyZero)) {
	// A 1D Gaussian in Y
	SkASSERT(3 == width);
	// Down the middle column of the kernel with a stride of width
	fill_in_1D_gaussian_kernel_with_stride(&kernel[1], height, width, twoSigmaSqrdY);
	} else {
	// A 1D Gaussian in X
	SkASSERT(SkScalarNearlyZero(twoSigmaSqrdY, SK_ScalarNearlyZero));
	SkASSERT(3 == height);
	// Down the middle row of the kernel with a stride of 1
	fill_in_1D_gaussian_kernel_with_stride(&kernel[width], width, 1, twoSigmaSqrdX);
	}
	return;
	}

	const float sigmaXDenom = 1.0f / twoSigmaSqrdX;
	const float sigmaYDenom = 1.0f / twoSigmaSqrdY;
	const int xRadius = width / 2;
	const int yRadius = height / 2;

	float sum = 0.0f;
	for (int x = 0; x < width; x++) {
	float xTerm = static_cast<float>(x - xRadius);
	xTerm = xTerm * xTerm * sigmaXDenom;
	for (int y = 0; y < height; y++) {
	float yTerm = static_cast<float>(y - yRadius);
	float xyTerm = sk_float_exp(-(xTerm + yTerm * yTerm * sigmaYDenom));
	// Note that the constant term (1/(sqrt(2pisigma^2)) of the Gaussian
	// is dropped here, since we renormalize the kernel below.
	kernel[y * width + x] = xyTerm;
	sum += xyTerm;
	}
	}
	// Normalize the kernel
	float scale = 1.0f / sum;
	for (int i = 0; i < width * height; ++i) {
	kernel[i] *= scale;
	}
	}

	std::unique_ptr<GrFragmentProcessor> GrMatrixConvolutionEffect::Make(GrSurfaceProxyView srcView,
	const SkIRect& srcBounds,
	const SkISize& kernelSize,
	const SkScalar* kernel,
	SkScalar gain,
	SkScalar bias,
	const SkIPoint& kernelOffset,
	GrSamplerState::WrapMode wm,
	bool convolveAlpha,
	const GrCaps& caps) {
	GrSamplerState sampler(wm, GrSamplerState::Filter::kNearest);
	auto child = GrTextureEffect::MakeSubset(std::move(srcView), kPremul_SkAlphaType, SkMatrix::I(),
	sampler, SkRect::Make(srcBounds), caps);
	return std::unique_ptr<GrFragmentProcessor>(new GrMatrixConvolutionEffect(
	std::move(child), kernelSize, kernel, gain, bias, kernelOffset, convolveAlpha));
	}

	std::unique_ptr<GrFragmentProcessor> GrMatrixConvolutionEffect::MakeGaussian(
	GrSurfaceProxyView srcView,
	const SkIRect& srcBounds,
	const SkISize& kernelSize,
	SkScalar gain,
	SkScalar bias,
	const SkIPoint& kernelOffset,
	GrSamplerState::WrapMode wm,
	bool convolveAlpha,
	SkScalar sigmaX,
	SkScalar sigmaY,
	const GrCaps& caps) {
	float kernel[MAX_KERNEL_SIZE];

	fill_in_2D_gaussian_kernel(kernel, kernelSize.width(), kernelSize.height(), sigmaX, sigmaY);
	return Make(std::move(srcView), srcBounds, kernelSize, kernel, gain, bias, kernelOffset, wm,
	convolveAlpha, caps);
	}

	GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrMatrixConvolutionEffect);

	#if GR_TEST_UTILS
	std::unique_ptr<GrFragmentProcessor> GrMatrixConvolutionEffect::TestCreate(GrProcessorTestData* d) {
	auto [view, ct, at] = d->randomView();

	int width = d->fRandom->nextRangeU(1, MAX_KERNEL_SIZE);
	int height = d->fRandom->nextRangeU(1, MAX_KERNEL_SIZE / width);
	SkISize kernelSize = SkISize::Make(width, height);
	std::unique_ptr<SkScalar[]> kernel(new SkScalar[width * height]);
	for (int i = 0; i < width * height; i++) {
	kernel.get()[i] = d->fRandom->nextSScalar1();
	}
	SkScalar gain = d->fRandom->nextSScalar1();
	SkScalar bias = d->fRandom->nextSScalar1();

	uint32_t kernalOffsetX = d->fRandom->nextRangeU(0, kernelSize.width());
	uint32_t kernalOffsetY = d->fRandom->nextRangeU(0, kernelSize.height());
	SkIPoint kernelOffset = SkIPoint::Make(kernalOffsetX, kernalOffsetY);

	uint32_t boundsX = d->fRandom->nextRangeU(0, view.width());
	uint32_t boundsY = d->fRandom->nextRangeU(0, view.height());
	uint32_t boundsW = d->fRandom->nextRangeU(0, view.width());
	uint32_t boundsH = d->fRandom->nextRangeU(0, view.height());
	SkIRect bounds = SkIRect::MakeXYWH(boundsX, boundsY, boundsW, boundsH);

	auto wm = static_cast<GrSamplerState::WrapMode>(
	d->fRandom->nextULessThan(GrSamplerState::kWrapModeCount));
	bool convolveAlpha = d->fRandom->nextBool();

	return GrMatrixConvolutionEffect::Make(std::move(view),
	bounds,
	kernelSize,
	kernel.get(),
	gain,
	bias,
	kernelOffset,
	wm,
	convolveAlpha,
	*d->caps());
	}
	#endif