gm/fp_sample_chaining.cpp - platform/external/skia - Gitiles

 /*
  * Copyright 2019 Google LLC.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */

 #include "gm/gm.h"
 #include "include/core/SkFont.h"
 #include "include/effects/SkRuntimeEffect.h"
 #include "src/gpu/GrBitmapTextureMaker.h"
 #include "src/gpu/GrDirectContextPriv.h"
 #include "src/gpu/glsl/GrGLSLFragmentShaderBuilder.h"
 #include "src/gpu/ops/GrFillRectOp.h"
 #include "tools/ToolUtils.h"

 // Samples child with a constant (literal) matrix
 // Scales along X
 class ConstantMatrixEffect : public GrFragmentProcessor {
 public:
     static constexpr GrProcessor::ClassID CLASS_ID = (GrProcessor::ClassID) 3;

     ConstantMatrixEffect(std::unique_ptr<GrFragmentProcessor> child)
             : GrFragmentProcessor(CLASS_ID, kNone_OptimizationFlags) {
         this->registerChild(std::move(child),
                             SkSL::SampleUsage::UniformMatrix(
                                 "float3x3(float3(0.5, 0.0, 0.0), "
                                         "float3(0.0, 1.0, 0.0), "
                                         "float3(0.0, 0.0, 1.0))"));
     }

     const char* name() const override { return "ConstantMatrixEffect"; }
     void onGetGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder*) const override {}
     bool onIsEqual(const GrFragmentProcessor& that) const override { return this == &that; }
     std::unique_ptr<GrFragmentProcessor> clone() const override { return nullptr; }

     GrGLSLFragmentProcessor* onCreateGLSLInstance() const override {
         class Impl : public GrGLSLFragmentProcessor {
             void emitCode(EmitArgs& args) override {
                 SkString sample = this->invokeChildWithMatrix(0, args);
                 args.fFragBuilder->codeAppendf("return %s;\n", sample.c_str());
             }
         };
         return new Impl;
     }
 };

 // Samples child with a uniform matrix (functionally identical to GrMatrixEffect)
 // Scales along Y
 class UniformMatrixEffect : public GrFragmentProcessor {
 public:
     static constexpr GrProcessor::ClassID CLASS_ID = (GrProcessor::ClassID) 4;

     UniformMatrixEffect(std::unique_ptr<GrFragmentProcessor> child)
             : GrFragmentProcessor(CLASS_ID, kNone_OptimizationFlags) {
         this->registerChild(std::move(child), SkSL::SampleUsage::UniformMatrix("matrix"));
     }

     const char* name() const override { return "UniformMatrixEffect"; }
     void onGetGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder*) const override {}
     bool onIsEqual(const GrFragmentProcessor& that) const override { return this == &that; }
     std::unique_ptr<GrFragmentProcessor> clone() const override { return nullptr; }

     GrGLSLFragmentProcessor* onCreateGLSLInstance() const override {
         class Impl : public GrGLSLFragmentProcessor {
             void emitCode(EmitArgs& args) override {
                 fMatrixVar = args.fUniformHandler->addUniform(&args.fFp, kFragment_GrShaderFlag,
                                                               kFloat3x3_GrSLType, "matrix");
                 SkString sample = this->invokeChildWithMatrix(0, args);
                 args.fFragBuilder->codeAppendf("return %s;\n", sample.c_str());
             }
             void onSetData(const GrGLSLProgramDataManager& pdman,
                            const GrFragmentProcessor& proc) override {
                 pdman.setSkMatrix(fMatrixVar, SkMatrix::Scale(1, 0.5f));
             }
             UniformHandle fMatrixVar;
         };
         return new Impl;
     }
 };

 // Samples child with a variable matrix
 // Translates along X
 // Typically, kVariable would be due to multiple sample(matrix) invocations, but this artificially
 // uses kVariable with a single (constant) matrix.
 class VariableMatrixEffect : public GrFragmentProcessor {
 public:
     static constexpr GrProcessor::ClassID CLASS_ID = (GrProcessor::ClassID) 5;

     VariableMatrixEffect(std::unique_ptr<GrFragmentProcessor> child)
             : GrFragmentProcessor(CLASS_ID, kNone_OptimizationFlags) {
         this->registerChild(std::move(child), SkSL::SampleUsage::VariableMatrix());
     }

     const char* name() const override { return "VariableMatrixEffect"; }
     void onGetGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder*) const override {}
     bool onIsEqual(const GrFragmentProcessor& that) const override { return this == &that; }
     std::unique_ptr<GrFragmentProcessor> clone() const override { return nullptr; }

     GrGLSLFragmentProcessor* onCreateGLSLInstance() const override {
         class Impl : public GrGLSLFragmentProcessor {
             void emitCode(EmitArgs& args) override {
                 SkString sample = this->invokeChildWithMatrix(
                         0, args, "float3x3(1, 0, 0, 0, 1, 0, 8, 0, 1)");
                 args.fFragBuilder->codeAppendf("return %s;\n", sample.c_str());
             }
         };
         return new Impl;
     }
 };

 // Samples child with explicit coords
 // Translates along Y
 class ExplicitCoordEffect : public GrFragmentProcessor {
 public:
     static constexpr GrProcessor::ClassID CLASS_ID = (GrProcessor::ClassID) 6;

     ExplicitCoordEffect(std::unique_ptr<GrFragmentProcessor> child)
             : GrFragmentProcessor(CLASS_ID, kNone_OptimizationFlags) {
         this->registerChild(std::move(child), SkSL::SampleUsage::Explicit());
         this->setUsesSampleCoordsDirectly();
     }

     const char* name() const override { return "ExplicitCoordEffect"; }
     void onGetGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder*) const override {}
     bool onIsEqual(const GrFragmentProcessor& that) const override { return this == &that; }
     std::unique_ptr<GrFragmentProcessor> clone() const override { return nullptr; }

     GrGLSLFragmentProcessor* onCreateGLSLInstance() const override {
         class Impl : public GrGLSLFragmentProcessor {
             void emitCode(EmitArgs& args) override {
                 args.fFragBuilder->codeAppendf("float2 coord = %s + float2(0, 8);",
                                                args.fSampleCoord);
                 SkString sample = this->invokeChild(0, args, "coord");
                 args.fFragBuilder->codeAppendf("return %s;\n", sample.c_str());
             }
         };
         return new Impl;
     }
 };

 // Generates test pattern
 class TestPatternEffect : public GrFragmentProcessor {
 public:
     static constexpr GrProcessor::ClassID CLASS_ID = (GrProcessor::ClassID) 7;

     TestPatternEffect() : GrFragmentProcessor(CLASS_ID, kNone_OptimizationFlags) {
         this->setUsesSampleCoordsDirectly();
     }

     const char* name() const override { return "TestPatternEffect"; }
     void onGetGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder*) const override {}
     bool onIsEqual(const GrFragmentProcessor& that) const override { return this == &that; }
     std::unique_ptr<GrFragmentProcessor> clone() const override { return nullptr; }

     GrGLSLFragmentProcessor* onCreateGLSLInstance() const override {
         class Impl : public GrGLSLFragmentProcessor {
             void emitCode(EmitArgs& args) override {
                 auto fb = args.fFragBuilder;
                 fb->codeAppendf("float2 coord = %s / 64.0;", args.fSampleCoord);
                 fb->codeAppendf("coord = floor(coord * 4) / 3;");
                 fb->codeAppendf("return half2(coord).rg01;\n");
             }
         };
         return new Impl;
     }
 };

 SkBitmap make_test_bitmap() {
     SkBitmap bitmap;
     bitmap.allocN32Pixels(64, 64);
     SkCanvas canvas(bitmap);

     SkFont font(ToolUtils::create_portable_typeface());
     const char* alpha = "ABCDEFGHIJKLMNOP";

     for (int i = 0; i < 16; ++i) {
         int tx = i % 4,
             ty = i / 4;
         int x = tx * 16,
             y = ty * 16;
         SkPaint paint;
         paint.setColor4f({ tx / 3.0f, ty / 3.0f, 0.0f, 1.0f });
         canvas.drawRect(SkRect::MakeXYWH(x, y, 16, 16), paint);
         paint.setColor4f({ (3-tx) / 3.0f, (3-ty)/3.0f, 1.0f, 1.0f });
         canvas.drawSimpleText(alpha + i, 1, SkTextEncoding::kUTF8, x + 3, y + 13, font, paint);
     }

     return bitmap;
 }

 enum EffectType {
     kConstant,
     kUniform,
     kVariable,
     kExplicit,
 };

 static std::unique_ptr<GrFragmentProcessor> wrap(std::unique_ptr<GrFragmentProcessor> fp,
                                                  EffectType effectType) {
     switch (effectType) {
         case kConstant:
             return std::make_unique<ConstantMatrixEffect>(std::move(fp));
         case kUniform:
             return std::make_unique<UniformMatrixEffect>(std::move(fp));
         case kVariable:
             return std::make_unique<VariableMatrixEffect>(std::move(fp));
         case kExplicit:
             return std::make_unique<ExplicitCoordEffect>(std::move(fp));
     }
     SkUNREACHABLE;
 }

 DEF_SIMPLE_GPU_GM(fp_sample_chaining, ctx, rtCtx, canvas, 380, 306) {
     SkBitmap bmp = make_test_bitmap();

     GrBitmapTextureMaker maker(ctx, bmp, GrImageTexGenPolicy::kDraw);
     int x = 10, y = 10;

     auto nextCol = [&] { x += (64 + 10); };
     auto nextRow = [&] { x = 10; y += (64 + 10); };

     auto draw = [&](std::initializer_list<EffectType> effects) {
         // Enable TestPatternEffect to get a fully procedural inner effect. It's not quite as nice
         // visually (no text labels in each box), but it avoids the extra GrMatrixEffect.
         // Switching it on actually triggers *more* shader compilation failures.
 #if 0
         auto fp = std::unique_ptr<GrFragmentProcessor>(new TestPatternEffect());
 #else
         auto view = maker.view(GrMipmapped::kNo);
         auto fp = GrTextureEffect::Make(std::move(view), maker.alphaType());
 #endif
         for (EffectType effectType : effects) {
             fp = wrap(std::move(fp), effectType);
         }
         GrPaint paint;
         paint.setColorFragmentProcessor(std::move(fp));
         rtCtx->drawRect(nullptr, std::move(paint), GrAA::kNo, SkMatrix::Translate(x, y),
                         SkRect::MakeIWH(64, 64));
         nextCol();
     };

     // Reminder, in every case, the chain is more complicated than it seems, because the
     // GrTextureEffect is wrapped in a GrMatrixEffect, which is subject to the same bugs that
     // we're testing (particularly the bug about owner/base in UniformMatrixEffect).

     // First row: no transform, then each one independently applied
     draw({});             // Identity (4 rows and columns)
     draw({ kConstant });  // Scale X axis by 2x (2 visible columns)
     draw({ kUniform  });  // Scale Y axis by 2x (2 visible rows)
     draw({ kVariable });  // Translate left by 8px
     draw({ kExplicit });  // Translate up by 8px
     nextRow();

     // Second row: transform duplicated
     draw({ kConstant, kUniform  });  // Scale XY by 2x (2 rows and columns)
     draw({ kConstant, kConstant });  // Scale X axis by 4x (1 visible column)
     draw({ kUniform,  kUniform  });  // Scale Y axis by 4x (1 visible row)
     draw({ kVariable, kVariable });  // Translate left by 16px
     draw({ kExplicit, kExplicit });  // Translate up by 16px
     nextRow();

     // Remember, these are applied inside out:
     draw({ kConstant, kExplicit }); // Scale X by 2x and translate up by 8px
     draw({ kConstant, kVariable }); // Scale X by 2x and translate left by 8px
     draw({ kUniform,  kVariable }); // Scale Y by 2x and translate left by 8px
     draw({ kUniform,  kExplicit }); // Scale Y by 2x and translate up by 8px
     draw({ kVariable, kExplicit }); // Translate left and up by 8px
     nextRow();

     draw({ kExplicit, kExplicit, kConstant }); // Scale X by 2x and translate up by 16px
     draw({ kVariable, kConstant }); // Scale X by 2x and translate left by 16px
     draw({ kVariable, kVariable, kUniform }); // Scale Y by 2x and translate left by 16px
     draw({ kExplicit, kUniform }); // Scale Y by 2x and translate up by 16px
     draw({ kExplicit, kUniform, kVariable, kConstant }); // Scale XY by 2x and translate xy 16px
 }

 const char* gConstantMatrixSkSL = R"(
     uniform shader child;
     half4 main(float2 xy) {
         return sample(child, float3x3(0.5, 0.0, 0.0,
                                       0.0, 1.0, 0.0,
                                       0.0, 0.0, 1.0));
     }
 )";

 const char* gUniformMatrixSkSL = R"(
     uniform shader child;
     uniform float3x3 matrix;
     half4 main(float2 xy) {
         return sample(child, matrix);
     }
 )";

 // This form (uniform * constant) is currently detected as variable, thanks to our limited analysis
 // when scanning for sample matrices. With that pulled into a separate local, it's highly unlikely
 // we'll ever treat this as anything else.
 const char* gVariableMatrixSkSL = R"(
     uniform shader child;
     uniform float3x3 matrix;
     half4 main(float2 xy) {
         float3x3 varMatrix = matrix * 0.5;
         return sample(child, varMatrix);
     }
 )";

 const char* gExplicitCoordSkSL = R"(
     uniform shader child;
     half4 main(float2 xy) {
         return sample(child, xy + float2(0, 8));
     }
 )";

 // Version of fp_sample_chaining that uses SkRuntimeEffect
 DEF_SIMPLE_GM(sksl_sample_chaining, canvas, 380, 306) {
     SkBitmap bmp = make_test_bitmap();

     sk_sp<SkRuntimeEffect> effects[4] = {
         std::get<0>(SkRuntimeEffect::Make(SkString(gConstantMatrixSkSL))),
         std::get<0>(SkRuntimeEffect::Make(SkString(gUniformMatrixSkSL))),
         std::get<0>(SkRuntimeEffect::Make(SkString(gVariableMatrixSkSL))),
         std::get<0>(SkRuntimeEffect::Make(SkString(gExplicitCoordSkSL))),
     };

     canvas->translate(10, 10);
     canvas->save();
     auto nextCol = [&] { canvas->translate(64 + 10, 0); };
     auto nextRow = [&] { canvas->restore(); canvas->translate(0, 64 + 10); canvas->save(); };

     auto draw = [&](std::initializer_list<EffectType> effectTypes) {
         auto shader = bmp.makeShader(SkSamplingOptions());

         for (EffectType effectType : effectTypes) {
             SkRuntimeShaderBuilder builder(effects[effectType]);
             builder.child("child") = shader;
             switch (effectType) {
                 case kUniform:
                     builder.uniform("matrix") = SkMatrix::Scale(1.0f, 0.5f);
                     break;
                 case kVariable:
                     builder.uniform("matrix") = SkMatrix::Translate(8, 0);
                     break;
                 default:
                     break;
             }
             shader = builder.makeShader(nullptr, true);
         }
         SkPaint paint;
         paint.setShader(shader);
         canvas->drawRect(SkRect::MakeWH(64, 64), paint);
         nextCol();
     };

     // Reminder, in every case, the chain is more complicated than it seems, because the
     // GrTextureEffect is wrapped in a GrMatrixEffect, which is subject to the same bugs that
     // we're testing (particularly the bug about owner/base in UniformMatrixEffect).

     // First row: no transform, then each one independently applied
     draw({});             // Identity (4 rows and columns)
     draw({ kConstant });  // Scale X axis by 2x (2 visible columns)
     draw({ kUniform  });  // Scale Y axis by 2x (2 visible rows)
     draw({ kVariable });  // Translate left by 8px
     draw({ kExplicit });  // Translate up by 8px
     nextRow();

     // Second row: transform duplicated
     draw({ kConstant, kUniform  });  // Scale XY by 2x (2 rows and columns)
     draw({ kConstant, kConstant });  // Scale X axis by 4x (1 visible column)
     draw({ kUniform,  kUniform  });  // Scale Y axis by 4x (1 visible row)
     draw({ kVariable, kVariable });  // Translate left by 16px
     draw({ kExplicit, kExplicit });  // Translate up by 16px
     nextRow();

     // Remember, these are applied inside out:
     draw({ kConstant, kExplicit }); // Scale X by 2x and translate up by 8px
     draw({ kConstant, kVariable }); // Scale X by 2x and translate left by 8px
     draw({ kUniform,  kVariable }); // Scale Y by 2x and translate left by 8px
     draw({ kUniform,  kExplicit }); // Scale Y by 2x and translate up by 8px
     draw({ kVariable, kExplicit }); // Translate left and up by 8px
     nextRow();

     draw({ kExplicit, kExplicit, kConstant }); // Scale X by 2x and translate up by 16px
     draw({ kVariable, kConstant }); // Scale X by 2x and translate left by 16px
     draw({ kVariable, kVariable, kUniform }); // Scale Y by 2x and translate left by 16px
     draw({ kExplicit, kUniform }); // Scale Y by 2x and translate up by 16px
     draw({ kExplicit, kUniform, kVariable, kConstant }); // Scale XY by 2x and translate xy 16px
 }
	/*
	* Copyright 2019 Google LLC.
	*
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/

	#include "gm/gm.h"
	#include "include/core/SkFont.h"
	#include "include/effects/SkRuntimeEffect.h"
	#include "src/gpu/GrBitmapTextureMaker.h"
	#include "src/gpu/GrDirectContextPriv.h"
	#include "src/gpu/glsl/GrGLSLFragmentShaderBuilder.h"
	#include "src/gpu/ops/GrFillRectOp.h"
	#include "tools/ToolUtils.h"

	// Samples child with a constant (literal) matrix
	// Scales along X
	class ConstantMatrixEffect : public GrFragmentProcessor {
	public:
	static constexpr GrProcessor::ClassID CLASS_ID = (GrProcessor::ClassID) 3;

	ConstantMatrixEffect(std::unique_ptr<GrFragmentProcessor> child)
	: GrFragmentProcessor(CLASS_ID, kNone_OptimizationFlags) {
	this->registerChild(std::move(child),
	SkSL::SampleUsage::UniformMatrix(
	"float3x3(float3(0.5, 0.0, 0.0), "
	"float3(0.0, 1.0, 0.0), "
	"float3(0.0, 0.0, 1.0))"));
	}

	const char* name() const override { return "ConstantMatrixEffect"; }
	void onGetGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder*) const override {}
	bool onIsEqual(const GrFragmentProcessor& that) const override { return this == &that; }
	std::unique_ptr<GrFragmentProcessor> clone() const override { return nullptr; }

	GrGLSLFragmentProcessor* onCreateGLSLInstance() const override {
	class Impl : public GrGLSLFragmentProcessor {
	void emitCode(EmitArgs& args) override {
	SkString sample = this->invokeChildWithMatrix(0, args);
	args.fFragBuilder->codeAppendf("return %s;\n", sample.c_str());
	}
	};
	return new Impl;
	}
	};

	// Samples child with a uniform matrix (functionally identical to GrMatrixEffect)
	// Scales along Y
	class UniformMatrixEffect : public GrFragmentProcessor {
	public:
	static constexpr GrProcessor::ClassID CLASS_ID = (GrProcessor::ClassID) 4;

	UniformMatrixEffect(std::unique_ptr<GrFragmentProcessor> child)
	: GrFragmentProcessor(CLASS_ID, kNone_OptimizationFlags) {
	this->registerChild(std::move(child), SkSL::SampleUsage::UniformMatrix("matrix"));
	}

	const char* name() const override { return "UniformMatrixEffect"; }
	void onGetGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder*) const override {}
	bool onIsEqual(const GrFragmentProcessor& that) const override { return this == &that; }
	std::unique_ptr<GrFragmentProcessor> clone() const override { return nullptr; }

	GrGLSLFragmentProcessor* onCreateGLSLInstance() const override {
	class Impl : public GrGLSLFragmentProcessor {
	void emitCode(EmitArgs& args) override {
	fMatrixVar = args.fUniformHandler->addUniform(&args.fFp, kFragment_GrShaderFlag,
	kFloat3x3_GrSLType, "matrix");
	SkString sample = this->invokeChildWithMatrix(0, args);
	args.fFragBuilder->codeAppendf("return %s;\n", sample.c_str());
	}
	void onSetData(const GrGLSLProgramDataManager& pdman,
	const GrFragmentProcessor& proc) override {
	pdman.setSkMatrix(fMatrixVar, SkMatrix::Scale(1, 0.5f));
	}
	UniformHandle fMatrixVar;
	};
	return new Impl;
	}
	};

	// Samples child with a variable matrix
	// Translates along X
	// Typically, kVariable would be due to multiple sample(matrix) invocations, but this artificially
	// uses kVariable with a single (constant) matrix.
	class VariableMatrixEffect : public GrFragmentProcessor {
	public:
	static constexpr GrProcessor::ClassID CLASS_ID = (GrProcessor::ClassID) 5;

	VariableMatrixEffect(std::unique_ptr<GrFragmentProcessor> child)
	: GrFragmentProcessor(CLASS_ID, kNone_OptimizationFlags) {
	this->registerChild(std::move(child), SkSL::SampleUsage::VariableMatrix());
	}

	const char* name() const override { return "VariableMatrixEffect"; }
	void onGetGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder*) const override {}
	bool onIsEqual(const GrFragmentProcessor& that) const override { return this == &that; }
	std::unique_ptr<GrFragmentProcessor> clone() const override { return nullptr; }

	GrGLSLFragmentProcessor* onCreateGLSLInstance() const override {
	class Impl : public GrGLSLFragmentProcessor {
	void emitCode(EmitArgs& args) override {
	SkString sample = this->invokeChildWithMatrix(
	0, args, "float3x3(1, 0, 0, 0, 1, 0, 8, 0, 1)");
	args.fFragBuilder->codeAppendf("return %s;\n", sample.c_str());
	}
	};
	return new Impl;
	}
	};

	// Samples child with explicit coords
	// Translates along Y
	class ExplicitCoordEffect : public GrFragmentProcessor {
	public:
	static constexpr GrProcessor::ClassID CLASS_ID = (GrProcessor::ClassID) 6;

	ExplicitCoordEffect(std::unique_ptr<GrFragmentProcessor> child)
	: GrFragmentProcessor(CLASS_ID, kNone_OptimizationFlags) {
	this->registerChild(std::move(child), SkSL::SampleUsage::Explicit());
	this->setUsesSampleCoordsDirectly();
	}

	const char* name() const override { return "ExplicitCoordEffect"; }
	void onGetGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder*) const override {}
	bool onIsEqual(const GrFragmentProcessor& that) const override { return this == &that; }
	std::unique_ptr<GrFragmentProcessor> clone() const override { return nullptr; }

	GrGLSLFragmentProcessor* onCreateGLSLInstance() const override {
	class Impl : public GrGLSLFragmentProcessor {
	void emitCode(EmitArgs& args) override {
	args.fFragBuilder->codeAppendf("float2 coord = %s + float2(0, 8);",
	args.fSampleCoord);
	SkString sample = this->invokeChild(0, args, "coord");
	args.fFragBuilder->codeAppendf("return %s;\n", sample.c_str());
	}
	};
	return new Impl;
	}
	};

	// Generates test pattern
	class TestPatternEffect : public GrFragmentProcessor {
	public:
	static constexpr GrProcessor::ClassID CLASS_ID = (GrProcessor::ClassID) 7;

	TestPatternEffect() : GrFragmentProcessor(CLASS_ID, kNone_OptimizationFlags) {
	this->setUsesSampleCoordsDirectly();
	}

	const char* name() const override { return "TestPatternEffect"; }
	void onGetGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder*) const override {}
	bool onIsEqual(const GrFragmentProcessor& that) const override { return this == &that; }
	std::unique_ptr<GrFragmentProcessor> clone() const override { return nullptr; }

	GrGLSLFragmentProcessor* onCreateGLSLInstance() const override {
	class Impl : public GrGLSLFragmentProcessor {
	void emitCode(EmitArgs& args) override {
	auto fb = args.fFragBuilder;
	fb->codeAppendf("float2 coord = %s / 64.0;", args.fSampleCoord);
	fb->codeAppendf("coord = floor(coord * 4) / 3;");
	fb->codeAppendf("return half2(coord).rg01;\n");
	}
	};
	return new Impl;
	}
	};

	SkBitmap make_test_bitmap() {
	SkBitmap bitmap;
	bitmap.allocN32Pixels(64, 64);
	SkCanvas canvas(bitmap);

	SkFont font(ToolUtils::create_portable_typeface());
	const char* alpha = "ABCDEFGHIJKLMNOP";

	for (int i = 0; i < 16; ++i) {
	int tx = i % 4,
	ty = i / 4;
	int x = tx * 16,
	y = ty * 16;
	SkPaint paint;
	paint.setColor4f({ tx / 3.0f, ty / 3.0f, 0.0f, 1.0f });
	canvas.drawRect(SkRect::MakeXYWH(x, y, 16, 16), paint);
	paint.setColor4f({ (3-tx) / 3.0f, (3-ty)/3.0f, 1.0f, 1.0f });
	canvas.drawSimpleText(alpha + i, 1, SkTextEncoding::kUTF8, x + 3, y + 13, font, paint);
	}

	return bitmap;
	}

	enum EffectType {
	kConstant,
	kUniform,
	kVariable,
	kExplicit,
	};

	static std::unique_ptr<GrFragmentProcessor> wrap(std::unique_ptr<GrFragmentProcessor> fp,
	EffectType effectType) {
	switch (effectType) {
	case kConstant:
	return std::make_unique<ConstantMatrixEffect>(std::move(fp));
	case kUniform:
	return std::make_unique<UniformMatrixEffect>(std::move(fp));
	case kVariable:
	return std::make_unique<VariableMatrixEffect>(std::move(fp));
	case kExplicit:
	return std::make_unique<ExplicitCoordEffect>(std::move(fp));
	}
	SkUNREACHABLE;
	}

	DEF_SIMPLE_GPU_GM(fp_sample_chaining, ctx, rtCtx, canvas, 380, 306) {
	SkBitmap bmp = make_test_bitmap();

	GrBitmapTextureMaker maker(ctx, bmp, GrImageTexGenPolicy::kDraw);
	int x = 10, y = 10;

	auto nextCol = [&] { x += (64 + 10); };
	auto nextRow = [&] { x = 10; y += (64 + 10); };

	auto draw = [&](std::initializer_list<EffectType> effects) {
	// Enable TestPatternEffect to get a fully procedural inner effect. It's not quite as nice
	// visually (no text labels in each box), but it avoids the extra GrMatrixEffect.
	// Switching it on actually triggers more shader compilation failures.
	#if 0
	auto fp = std::unique_ptr<GrFragmentProcessor>(new TestPatternEffect());
	#else
	auto view = maker.view(GrMipmapped::kNo);
	auto fp = GrTextureEffect::Make(std::move(view), maker.alphaType());
	#endif
	for (EffectType effectType : effects) {
	fp = wrap(std::move(fp), effectType);
	}
	GrPaint paint;
	paint.setColorFragmentProcessor(std::move(fp));
	rtCtx->drawRect(nullptr, std::move(paint), GrAA::kNo, SkMatrix::Translate(x, y),
	SkRect::MakeIWH(64, 64));
	nextCol();
	};

	// Reminder, in every case, the chain is more complicated than it seems, because the
	// GrTextureEffect is wrapped in a GrMatrixEffect, which is subject to the same bugs that
	// we're testing (particularly the bug about owner/base in UniformMatrixEffect).

	// First row: no transform, then each one independently applied
	draw({}); // Identity (4 rows and columns)
	draw({ kConstant }); // Scale X axis by 2x (2 visible columns)
	draw({ kUniform }); // Scale Y axis by 2x (2 visible rows)
	draw({ kVariable }); // Translate left by 8px
	draw({ kExplicit }); // Translate up by 8px
	nextRow();

	// Second row: transform duplicated
	draw({ kConstant, kUniform }); // Scale XY by 2x (2 rows and columns)
	draw({ kConstant, kConstant }); // Scale X axis by 4x (1 visible column)
	draw({ kUniform, kUniform }); // Scale Y axis by 4x (1 visible row)
	draw({ kVariable, kVariable }); // Translate left by 16px
	draw({ kExplicit, kExplicit }); // Translate up by 16px
	nextRow();

	// Remember, these are applied inside out:
	draw({ kConstant, kExplicit }); // Scale X by 2x and translate up by 8px
	draw({ kConstant, kVariable }); // Scale X by 2x and translate left by 8px
	draw({ kUniform, kVariable }); // Scale Y by 2x and translate left by 8px
	draw({ kUniform, kExplicit }); // Scale Y by 2x and translate up by 8px
	draw({ kVariable, kExplicit }); // Translate left and up by 8px
	nextRow();

	draw({ kExplicit, kExplicit, kConstant }); // Scale X by 2x and translate up by 16px
	draw({ kVariable, kConstant }); // Scale X by 2x and translate left by 16px
	draw({ kVariable, kVariable, kUniform }); // Scale Y by 2x and translate left by 16px
	draw({ kExplicit, kUniform }); // Scale Y by 2x and translate up by 16px
	draw({ kExplicit, kUniform, kVariable, kConstant }); // Scale XY by 2x and translate xy 16px
	}

	const char* gConstantMatrixSkSL = R"(
	uniform shader child;
	half4 main(float2 xy) {
	return sample(child, float3x3(0.5, 0.0, 0.0,
	0.0, 1.0, 0.0,
	0.0, 0.0, 1.0));
	}
	)";

	const char* gUniformMatrixSkSL = R"(
	uniform shader child;
	uniform float3x3 matrix;
	half4 main(float2 xy) {
	return sample(child, matrix);
	}
	)";

	// This form (uniform * constant) is currently detected as variable, thanks to our limited analysis
	// when scanning for sample matrices. With that pulled into a separate local, it's highly unlikely
	// we'll ever treat this as anything else.
	const char* gVariableMatrixSkSL = R"(
	uniform shader child;
	uniform float3x3 matrix;
	half4 main(float2 xy) {
	float3x3 varMatrix = matrix * 0.5;
	return sample(child, varMatrix);
	}
	)";

	const char* gExplicitCoordSkSL = R"(
	uniform shader child;
	half4 main(float2 xy) {
	return sample(child, xy + float2(0, 8));
	}
	)";

	// Version of fp_sample_chaining that uses SkRuntimeEffect
	DEF_SIMPLE_GM(sksl_sample_chaining, canvas, 380, 306) {
	SkBitmap bmp = make_test_bitmap();

	sk_sp<SkRuntimeEffect> effects[4] = {
	std::get<0>(SkRuntimeEffect::Make(SkString(gConstantMatrixSkSL))),
	std::get<0>(SkRuntimeEffect::Make(SkString(gUniformMatrixSkSL))),
	std::get<0>(SkRuntimeEffect::Make(SkString(gVariableMatrixSkSL))),
	std::get<0>(SkRuntimeEffect::Make(SkString(gExplicitCoordSkSL))),
	};

	canvas->translate(10, 10);
	canvas->save();
	auto nextCol = [&] { canvas->translate(64 + 10, 0); };
	auto nextRow = [&] { canvas->restore(); canvas->translate(0, 64 + 10); canvas->save(); };

	auto draw = [&](std::initializer_list<EffectType> effectTypes) {
	auto shader = bmp.makeShader(SkSamplingOptions());

	for (EffectType effectType : effectTypes) {
	SkRuntimeShaderBuilder builder(effects[effectType]);
	builder.child("child") = shader;
	switch (effectType) {
	case kUniform:
	builder.uniform("matrix") = SkMatrix::Scale(1.0f, 0.5f);
	break;
	case kVariable:
	builder.uniform("matrix") = SkMatrix::Translate(8, 0);
	break;
	default:
	break;
	}
	shader = builder.makeShader(nullptr, true);
	}
	SkPaint paint;
	paint.setShader(shader);
	canvas->drawRect(SkRect::MakeWH(64, 64), paint);
	nextCol();
	};

	// Reminder, in every case, the chain is more complicated than it seems, because the
	// GrTextureEffect is wrapped in a GrMatrixEffect, which is subject to the same bugs that
	// we're testing (particularly the bug about owner/base in UniformMatrixEffect).

	// First row: no transform, then each one independently applied
	draw({}); // Identity (4 rows and columns)
	draw({ kConstant }); // Scale X axis by 2x (2 visible columns)
	draw({ kUniform }); // Scale Y axis by 2x (2 visible rows)
	draw({ kVariable }); // Translate left by 8px
	draw({ kExplicit }); // Translate up by 8px
	nextRow();

	// Second row: transform duplicated
	draw({ kConstant, kUniform }); // Scale XY by 2x (2 rows and columns)
	draw({ kConstant, kConstant }); // Scale X axis by 4x (1 visible column)
	draw({ kUniform, kUniform }); // Scale Y axis by 4x (1 visible row)
	draw({ kVariable, kVariable }); // Translate left by 16px
	draw({ kExplicit, kExplicit }); // Translate up by 16px
	nextRow();

	// Remember, these are applied inside out:
	draw({ kConstant, kExplicit }); // Scale X by 2x and translate up by 8px
	draw({ kConstant, kVariable }); // Scale X by 2x and translate left by 8px
	draw({ kUniform, kVariable }); // Scale Y by 2x and translate left by 8px
	draw({ kUniform, kExplicit }); // Scale Y by 2x and translate up by 8px
	draw({ kVariable, kExplicit }); // Translate left and up by 8px
	nextRow();

	draw({ kExplicit, kExplicit, kConstant }); // Scale X by 2x and translate up by 16px
	draw({ kVariable, kConstant }); // Scale X by 2x and translate left by 16px
	draw({ kVariable, kVariable, kUniform }); // Scale Y by 2x and translate left by 16px
	draw({ kExplicit, kUniform }); // Scale Y by 2x and translate up by 16px
	draw({ kExplicit, kUniform, kVariable, kConstant }); // Scale XY by 2x and translate xy 16px
	}