src/gpu/ganesh/ops/PathStencilCoverOp.cpp - skia - Git at Google

 /*
  * Copyright 2021 Google LLC.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */

 #include "src/gpu/ganesh/ops/PathStencilCoverOp.h"

 #include "src/gpu/ganesh/GrEagerVertexAllocator.h"
 #include "src/gpu/ganesh/GrGpu.h"
 #include "src/gpu/ganesh/GrOpFlushState.h"
 #include "src/gpu/ganesh/GrRecordingContextPriv.h"
 #include "src/gpu/ganesh/GrResourceProvider.h"
 #include "src/gpu/ganesh/glsl/GrGLSLFragmentShaderBuilder.h"
 #include "src/gpu/ganesh/glsl/GrGLSLVarying.h"
 #include "src/gpu/ganesh/glsl/GrGLSLVertexGeoBuilder.h"
 #include "src/gpu/ganesh/ops/GrSimpleMeshDrawOpHelper.h"
 #include "src/gpu/ganesh/tessellate/GrPathTessellationShader.h"
 #include "src/gpu/tessellate/AffineMatrix.h"
 #include "src/gpu/tessellate/FixedCountBufferUtils.h"
 #include "src/gpu/tessellate/MiddleOutPolygonTriangulator.h"
 #include "src/gpu/tessellate/Tessellation.h"

 namespace {

 // Fills a path's bounding box, with subpixel outset to avoid possible T-junctions with extreme
 // edges of the path.
 // NOTE: The emitted geometry may not be axis-aligned, depending on the view matrix.
 class BoundingBoxShader : public GrGeometryProcessor {
 public:
     BoundingBoxShader(SkPMColor4f color, const GrShaderCaps& shaderCaps)
             : GrGeometryProcessor(kTessellate_BoundingBoxShader_ClassID)
             , fColor(color) {
         if (!shaderCaps.fVertexIDSupport) {
             constexpr static Attribute kUnitCoordAttrib("unitCoord", kFloat2_GrVertexAttribType,
                                                         SkSLType::kFloat2);
             this->setVertexAttributesWithImplicitOffsets(&kUnitCoordAttrib, 1);
         }
         constexpr static Attribute kInstanceAttribs[] = {
             {"matrix2d", kFloat4_GrVertexAttribType, SkSLType::kFloat4},
             {"translate", kFloat2_GrVertexAttribType, SkSLType::kFloat2},
             {"pathBounds", kFloat4_GrVertexAttribType, SkSLType::kFloat4}
         };
         this->setInstanceAttributesWithImplicitOffsets(kInstanceAttribs,
                                                        std::size(kInstanceAttribs));
     }

 private:
     const char* name() const final { return "tessellate_BoundingBoxShader"; }
     void addToKey(const GrShaderCaps&, skgpu::KeyBuilder*) const final {}
     std::unique_ptr<ProgramImpl> makeProgramImpl(const GrShaderCaps&) const final;

     const SkPMColor4f fColor;
 };

 std::unique_ptr<GrGeometryProcessor::ProgramImpl> BoundingBoxShader::makeProgramImpl(
         const GrShaderCaps&) const {
     class Impl : public ProgramImpl {
     public:
         void setData(const GrGLSLProgramDataManager& pdman,
                      const GrShaderCaps&,
                      const GrGeometryProcessor& gp) override {
             const SkPMColor4f& color = gp.cast<BoundingBoxShader>().fColor;
             pdman.set4f(fColorUniform, color.fR, color.fG, color.fB, color.fA);
         }

     private:
         void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) final {
             args.fVaryingHandler->emitAttributes(args.fGeomProc);

             // Vertex shader.
             if (args.fShaderCaps->fVertexIDSupport) {
                 // If we don't have sk_VertexID support then "unitCoord" already came in as a vertex
                 // attrib.
                 args.fVertBuilder->codeAppend(
                 "float2 unitCoord = float2(sk_VertexID & 1, sk_VertexID >> 1);");
             }
             args.fVertBuilder->codeAppend(
             // Bloat the bounding box by 1/4px to be certain we will reset every stencil value.
             "float2x2 M_ = inverse(float2x2(matrix2d.xy, matrix2d.zw));"
             "float2 bloat = float2(abs(M_[0]) + abs(M_[1])) * .25;"

             // Find the vertex position.
             "float2 localcoord = mix(pathBounds.xy - bloat, pathBounds.zw + bloat, unitCoord);"
             "float2 vertexpos = float2x2(matrix2d.xy, matrix2d.zw) * localcoord + translate;"
             );
             gpArgs->fLocalCoordVar.set(SkSLType::kFloat2, "localcoord");
             gpArgs->fPositionVar.set(SkSLType::kFloat2, "vertexpos");

             // Fragment shader.
             const char* color;
             fColorUniform = args.fUniformHandler->addUniform(nullptr, kFragment_GrShaderFlag,
                                                              SkSLType::kHalf4, "color", &color);
             args.fFragBuilder->codeAppendf("half4 %s = %s;", args.fOutputColor, color);
             args.fFragBuilder->codeAppendf("const half4 %s = half4(1);", args.fOutputCoverage);
         }

         GrGLSLUniformHandler::UniformHandle fColorUniform;
     };

     return std::make_unique<Impl>();
 }

 }  // anonymous namespace

 namespace skgpu::v1 {

 void PathStencilCoverOp::visitProxies(const GrVisitProxyFunc& func) const {
     if (fCoverBBoxProgram) {
         fCoverBBoxProgram->pipeline().visitProxies(func);
     } else {
         fProcessors.visitProxies(func);
     }
 }

 GrDrawOp::FixedFunctionFlags PathStencilCoverOp::fixedFunctionFlags() const {
     auto flags = FixedFunctionFlags::kUsesStencil;
     if (fAAType != GrAAType::kNone) {
         flags |= FixedFunctionFlags::kUsesHWAA;
     }
     return flags;
 }

 GrProcessorSet::Analysis PathStencilCoverOp::finalize(const GrCaps& caps,
                                                       const GrAppliedClip* clip,
                                                       GrClampType clampType) {
     return fProcessors.finalize(fColor, GrProcessorAnalysisCoverage::kNone, clip, nullptr, caps,
                                 clampType, &fColor);
 }

 void PathStencilCoverOp::prePreparePrograms(const GrTessellationShader::ProgramArgs& args,
                                             GrAppliedClip&& appliedClip) {
     SkASSERT(!fTessellator);
     SkASSERT(!fStencilFanProgram);
     SkASSERT(!fStencilPathProgram);
     SkASSERT(!fCoverBBoxProgram);

     // We transform paths on the CPU. This allows for better batching.
     const SkMatrix& shaderMatrix = SkMatrix::I();
     auto pipelineFlags = (fPathFlags & FillPathFlags::kWireframe)
             ? GrPipeline::InputFlags::kWireframe
             : GrPipeline::InputFlags::kNone;
     const GrPipeline* stencilPipeline = GrPathTessellationShader::MakeStencilOnlyPipeline(
             args, fAAType, appliedClip.hardClip(), pipelineFlags);
     const GrUserStencilSettings* stencilSettings = GrPathTessellationShader::StencilPathSettings(
                     GrFillRuleForPathFillType(this->pathFillType()));

     if (fTotalCombinedPathVerbCnt > 50 &&
         this->bounds().height() * this->bounds().width() > 256 * 256) {
         // Large complex paths do better with a dedicated triangle shader for the inner fan.
         // This takes less PCI bus bandwidth (6 floats per triangle instead of 8) and allows us
         // to make sure it has an efficient middle-out topology.
         auto shader = GrPathTessellationShader::MakeSimpleTriangleShader(args.fArena,
                                                                          shaderMatrix,
                                                                          SK_PMColor4fTRANSPARENT);
         fStencilFanProgram = GrTessellationShader::MakeProgram(args,
                                                                shader,
                                                                stencilPipeline,
                                                                stencilSettings);
         fTessellator = PathCurveTessellator::Make(args.fArena,
                                                   args.fCaps->shaderCaps()->fInfinitySupport);
     } else {
         fTessellator = PathWedgeTessellator::Make(args.fArena,
                                                   args.fCaps->shaderCaps()->fInfinitySupport);
     }
     auto* tessShader = GrPathTessellationShader::Make(*args.fCaps->shaderCaps(),
                                                       args.fArena,
                                                       shaderMatrix,
                                                       SK_PMColor4fTRANSPARENT,
                                                       fTessellator->patchAttribs());
     fStencilPathProgram = GrTessellationShader::MakeProgram(args,
                                                             tessShader,
                                                             stencilPipeline,
                                                             stencilSettings);

     if (!(fPathFlags & FillPathFlags::kStencilOnly)) {
         // Create a program that draws a bounding box over the path and fills its stencil coverage
         // into the color buffer.
         auto* bboxShader = args.fArena->make<BoundingBoxShader>(fColor, *args.fCaps->shaderCaps());
         auto* bboxPipeline = GrTessellationShader::MakePipeline(args, fAAType,
                                                                 std::move(appliedClip),
                                                                 std::move(fProcessors));
         auto* bboxStencil = GrPathTessellationShader::TestAndResetStencilSettings(
                 SkPathFillType_IsInverse(this->pathFillType()));
         fCoverBBoxProgram = GrSimpleMeshDrawOpHelper::CreateProgramInfo(
                 args.fCaps,
                 args.fArena,
                 bboxPipeline,
                 args.fWriteView,
                 args.fUsesMSAASurface,
                 bboxShader,
                 GrPrimitiveType::kTriangleStrip,
                 args.fXferBarrierFlags,
                 args.fColorLoadOp,
                 bboxStencil);
     }
 }

 void PathStencilCoverOp::onPrePrepare(GrRecordingContext* context,
                                       const GrSurfaceProxyView& writeView, GrAppliedClip* clip,
                                       const GrDstProxyView& dstProxyView,
                                       GrXferBarrierFlags renderPassXferBarriers,
                                       GrLoadOp colorLoadOp) {
     // DMSAA is not supported on DDL.
     bool usesMSAASurface = writeView.asRenderTargetProxy()->numSamples() > 1;
     this->prePreparePrograms({context->priv().recordTimeAllocator(), writeView, usesMSAASurface,
                              &dstProxyView, renderPassXferBarriers, colorLoadOp,
                              context->priv().caps()},
                              (clip) ? std::move(*clip) : GrAppliedClip::Disabled());
     if (fStencilFanProgram) {
         context->priv().recordProgramInfo(fStencilFanProgram);
     }
     if (fStencilPathProgram) {
         context->priv().recordProgramInfo(fStencilPathProgram);
     }
     if (fCoverBBoxProgram) {
         context->priv().recordProgramInfo(fCoverBBoxProgram);
     }
 }

 SKGPU_DECLARE_STATIC_UNIQUE_KEY(gUnitQuadBufferKey);

 void PathStencilCoverOp::onPrepare(GrOpFlushState* flushState) {
     if (!fTessellator) {
         this->prePreparePrograms({flushState->allocator(), flushState->writeView(),
                                  flushState->usesMSAASurface(), &flushState->dstProxyView(),
                                  flushState->renderPassBarriers(), flushState->colorLoadOp(),
                                  &flushState->caps()}, flushState->detachAppliedClip());
         if (!fTessellator) {
             return;
         }
     }

     if (fStencilFanProgram) {
         // The inner fan isn't built into the tessellator. Generate a standard Redbook fan with a
         // middle-out topology.
         GrEagerDynamicVertexAllocator vertexAlloc(flushState, &fFanBuffer, &fFanBaseVertex);
         // Path fans might have an extra edge from an implicit kClose at the end, but they also
         // always begin with kMove. So the max possible number of edges in a single path is equal to
         // the number of verbs. Therefore, the max number of combined fan edges in a path list is
         // the number of combined verbs from the paths in the list.
         // A single n-sided polygon is fanned by n-2 triangles. Multiple polygons with a combined
         // edge count of n are fanned by strictly fewer triangles.
         int maxTrianglesInFans = std::max(fTotalCombinedPathVerbCnt - 2, 0);
         int fanTriangleCount = 0;
         if (VertexWriter triangleVertexWriter =
                     vertexAlloc.lockWriter(sizeof(SkPoint), maxTrianglesInFans * 3)) {
             for (auto [pathMatrix, path, color] : *fPathDrawList) {
                 tess::AffineMatrix m(pathMatrix);
                 for (tess::PathMiddleOutFanIter it(path); !it.done();) {
                     for (auto [p0, p1, p2] : it.nextStack()) {
                         triangleVertexWriter << m.map2Points(p0, p1) << m.mapPoint(p2);
                         ++fanTriangleCount;
                     }
                 }
             }


             SkASSERT(fanTriangleCount <= maxTrianglesInFans);
             fFanVertexCount = fanTriangleCount * 3;
             vertexAlloc.unlock(fFanVertexCount);
         }
     }

     auto tessShader = &fStencilPathProgram->geomProc().cast<GrPathTessellationShader>();
     fTessellator->prepare(flushState,
                           tessShader->viewMatrix(),
                           *fPathDrawList,
                           fTotalCombinedPathVerbCnt);

     if (fCoverBBoxProgram) {
         size_t instanceStride = fCoverBBoxProgram->geomProc().instanceStride();
         VertexWriter vertexWriter = flushState->makeVertexWriter(instanceStride,
                                                                  fPathCount,
                                                                  &fBBoxBuffer,
                                                                  &fBBoxBaseInstance);
         SkDEBUGCODE(int pathCount = 0;)
         for (auto [pathMatrix, path, color] : *fPathDrawList) {
             SkDEBUGCODE(auto end = vertexWriter.mark(instanceStride));
             vertexWriter << pathMatrix.getScaleX()
                          << pathMatrix.getSkewY()
                          << pathMatrix.getSkewX()
                          << pathMatrix.getScaleY()
                          << pathMatrix.getTranslateX()
                          << pathMatrix.getTranslateY();
             if (path.isInverseFillType()) {
                 // Fill the entire backing store to make sure we clear every stencil value back to
                 // 0. If there is a scissor it will have already clipped the stencil draw.
                 auto rtBounds =
                         flushState->writeView().asRenderTargetProxy()->backingStoreBoundsRect();
                 SkASSERT(rtBounds == fOriginalDrawBounds);
                 SkRect pathSpaceRTBounds;
                 if (SkMatrixPriv::InverseMapRect(pathMatrix, &pathSpaceRTBounds, rtBounds)) {
                     vertexWriter << pathSpaceRTBounds;
                 } else {
                     vertexWriter << path.getBounds();
                 }
             } else {
                 vertexWriter << path.getBounds();
             }
             SkASSERT(vertexWriter.mark() == end);
             SkDEBUGCODE(++pathCount;)
         }
         SkASSERT(pathCount == fPathCount);
     }

     if (!flushState->caps().shaderCaps()->fVertexIDSupport) {
         constexpr static SkPoint kUnitQuad[4] = {{0,0}, {0,1}, {1,0}, {1,1}};

         SKGPU_DEFINE_STATIC_UNIQUE_KEY(gUnitQuadBufferKey);

         fBBoxVertexBufferIfNoIDSupport = flushState->resourceProvider()->findOrMakeStaticBuffer(
                 GrGpuBufferType::kVertex, sizeof(kUnitQuad), kUnitQuad, gUnitQuadBufferKey);
     }
 }

 void PathStencilCoverOp::onExecute(GrOpFlushState* flushState, const SkRect& chainBounds) {
     if (!fTessellator) {
         return;
     }

     if (fCoverBBoxProgram &&
         fCoverBBoxProgram->geomProc().hasVertexAttributes() &&
         !fBBoxVertexBufferIfNoIDSupport) {
         return;
     }

     // Stencil the inner fan, if any.
     if (fFanVertexCount > 0) {
         SkASSERT(fStencilFanProgram);
         SkASSERT(fFanBuffer);
         flushState->bindPipelineAndScissorClip(*fStencilFanProgram, this->bounds());
         flushState->bindBuffers(nullptr, nullptr, fFanBuffer);
         flushState->draw(fFanVertexCount, fFanBaseVertex);
     }

     // Stencil the rest of the path.
     SkASSERT(fStencilPathProgram);
     flushState->bindPipelineAndScissorClip(*fStencilPathProgram, this->bounds());
     fTessellator->draw(flushState);

     // Fill in the bounding box (if not in stencil-only mode).
     if (fCoverBBoxProgram) {
         flushState->bindPipelineAndScissorClip(*fCoverBBoxProgram, this->bounds());
         flushState->bindTextures(fCoverBBoxProgram->geomProc(), nullptr,
                                  fCoverBBoxProgram->pipeline());
         flushState->bindBuffers(nullptr, fBBoxBuffer, fBBoxVertexBufferIfNoIDSupport);
         flushState->drawInstanced(fPathCount, fBBoxBaseInstance, 4, 0);
     }
 }

 } // namespace skgpu::v1
	/*
	* Copyright 2021 Google LLC.
	*
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/

	#include "src/gpu/ganesh/ops/PathStencilCoverOp.h"

	#include "src/gpu/ganesh/GrEagerVertexAllocator.h"
	#include "src/gpu/ganesh/GrGpu.h"
	#include "src/gpu/ganesh/GrOpFlushState.h"
	#include "src/gpu/ganesh/GrRecordingContextPriv.h"
	#include "src/gpu/ganesh/GrResourceProvider.h"
	#include "src/gpu/ganesh/glsl/GrGLSLFragmentShaderBuilder.h"
	#include "src/gpu/ganesh/glsl/GrGLSLVarying.h"
	#include "src/gpu/ganesh/glsl/GrGLSLVertexGeoBuilder.h"
	#include "src/gpu/ganesh/ops/GrSimpleMeshDrawOpHelper.h"
	#include "src/gpu/ganesh/tessellate/GrPathTessellationShader.h"
	#include "src/gpu/tessellate/AffineMatrix.h"
	#include "src/gpu/tessellate/FixedCountBufferUtils.h"
	#include "src/gpu/tessellate/MiddleOutPolygonTriangulator.h"
	#include "src/gpu/tessellate/Tessellation.h"

	namespace {

	// Fills a path's bounding box, with subpixel outset to avoid possible T-junctions with extreme
	// edges of the path.
	// NOTE: The emitted geometry may not be axis-aligned, depending on the view matrix.
	class BoundingBoxShader : public GrGeometryProcessor {
	public:
	BoundingBoxShader(SkPMColor4f color, const GrShaderCaps& shaderCaps)
	: GrGeometryProcessor(kTessellate_BoundingBoxShader_ClassID)
	, fColor(color) {
	if (!shaderCaps.fVertexIDSupport) {
	constexpr static Attribute kUnitCoordAttrib("unitCoord", kFloat2_GrVertexAttribType,
	SkSLType::kFloat2);
	this->setVertexAttributesWithImplicitOffsets(&kUnitCoordAttrib, 1);
	}
	constexpr static Attribute kInstanceAttribs[] = {
	{"matrix2d", kFloat4_GrVertexAttribType, SkSLType::kFloat4},
	{"translate", kFloat2_GrVertexAttribType, SkSLType::kFloat2},
	{"pathBounds", kFloat4_GrVertexAttribType, SkSLType::kFloat4}
	};
	this->setInstanceAttributesWithImplicitOffsets(kInstanceAttribs,
	std::size(kInstanceAttribs));
	}

	private:
	const char* name() const final { return "tessellate_BoundingBoxShader"; }
	void addToKey(const GrShaderCaps&, skgpu::KeyBuilder*) const final {}
	std::unique_ptr<ProgramImpl> makeProgramImpl(const GrShaderCaps&) const final;

	const SkPMColor4f fColor;
	};

	std::unique_ptr<GrGeometryProcessor::ProgramImpl> BoundingBoxShader::makeProgramImpl(
	const GrShaderCaps&) const {
	class Impl : public ProgramImpl {
	public:
	void setData(const GrGLSLProgramDataManager& pdman,
	const GrShaderCaps&,
	const GrGeometryProcessor& gp) override {
	const SkPMColor4f& color = gp.cast<BoundingBoxShader>().fColor;
	pdman.set4f(fColorUniform, color.fR, color.fG, color.fB, color.fA);
	}

	private:
	void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) final {
	args.fVaryingHandler->emitAttributes(args.fGeomProc);

	// Vertex shader.
	if (args.fShaderCaps->fVertexIDSupport) {
	// If we don't have sk_VertexID support then "unitCoord" already came in as a vertex
	// attrib.
	args.fVertBuilder->codeAppend(
	"float2 unitCoord = float2(sk_VertexID & 1, sk_VertexID >> 1);");
	}
	args.fVertBuilder->codeAppend(
	// Bloat the bounding box by 1/4px to be certain we will reset every stencil value.
	"float2x2 M_ = inverse(float2x2(matrix2d.xy, matrix2d.zw));"
	"float2 bloat = float2(abs(M_[0]) + abs(M_[1])) * .25;"

	// Find the vertex position.
	"float2 localcoord = mix(pathBounds.xy - bloat, pathBounds.zw + bloat, unitCoord);"
	"float2 vertexpos = float2x2(matrix2d.xy, matrix2d.zw) * localcoord + translate;"
	);
	gpArgs->fLocalCoordVar.set(SkSLType::kFloat2, "localcoord");
	gpArgs->fPositionVar.set(SkSLType::kFloat2, "vertexpos");

	// Fragment shader.
	const char* color;
	fColorUniform = args.fUniformHandler->addUniform(nullptr, kFragment_GrShaderFlag,
	SkSLType::kHalf4, "color", &color);
	args.fFragBuilder->codeAppendf("half4 %s = %s;", args.fOutputColor, color);
	args.fFragBuilder->codeAppendf("const half4 %s = half4(1);", args.fOutputCoverage);
	}

	GrGLSLUniformHandler::UniformHandle fColorUniform;
	};

	return std::make_unique<Impl>();
	}

	} // anonymous namespace

	namespace skgpu::v1 {

	void PathStencilCoverOp::visitProxies(const GrVisitProxyFunc& func) const {
	if (fCoverBBoxProgram) {
	fCoverBBoxProgram->pipeline().visitProxies(func);
	} else {
	fProcessors.visitProxies(func);
	}
	}

	GrDrawOp::FixedFunctionFlags PathStencilCoverOp::fixedFunctionFlags() const {
	auto flags = FixedFunctionFlags::kUsesStencil;
	if (fAAType != GrAAType::kNone) {
	flags \|= FixedFunctionFlags::kUsesHWAA;
	}
	return flags;
	}

	GrProcessorSet::Analysis PathStencilCoverOp::finalize(const GrCaps& caps,
	const GrAppliedClip* clip,
	GrClampType clampType) {
	return fProcessors.finalize(fColor, GrProcessorAnalysisCoverage::kNone, clip, nullptr, caps,
	clampType, &fColor);
	}

	void PathStencilCoverOp::prePreparePrograms(const GrTessellationShader::ProgramArgs& args,
	GrAppliedClip&& appliedClip) {
	SkASSERT(!fTessellator);
	SkASSERT(!fStencilFanProgram);
	SkASSERT(!fStencilPathProgram);
	SkASSERT(!fCoverBBoxProgram);

	// We transform paths on the CPU. This allows for better batching.
	const SkMatrix& shaderMatrix = SkMatrix::I();
	auto pipelineFlags = (fPathFlags & FillPathFlags::kWireframe)
	? GrPipeline::InputFlags::kWireframe
	: GrPipeline::InputFlags::kNone;
	const GrPipeline* stencilPipeline = GrPathTessellationShader::MakeStencilOnlyPipeline(
	args, fAAType, appliedClip.hardClip(), pipelineFlags);
	const GrUserStencilSettings* stencilSettings = GrPathTessellationShader::StencilPathSettings(
	GrFillRuleForPathFillType(this->pathFillType()));

	if (fTotalCombinedPathVerbCnt > 50 &&
	this->bounds().height() * this->bounds().width() > 256 * 256) {
	// Large complex paths do better with a dedicated triangle shader for the inner fan.
	// This takes less PCI bus bandwidth (6 floats per triangle instead of 8) and allows us
	// to make sure it has an efficient middle-out topology.
	auto shader = GrPathTessellationShader::MakeSimpleTriangleShader(args.fArena,
	shaderMatrix,
	SK_PMColor4fTRANSPARENT);
	fStencilFanProgram = GrTessellationShader::MakeProgram(args,
	shader,
	stencilPipeline,
	stencilSettings);
	fTessellator = PathCurveTessellator::Make(args.fArena,
	args.fCaps->shaderCaps()->fInfinitySupport);
	} else {
	fTessellator = PathWedgeTessellator::Make(args.fArena,
	args.fCaps->shaderCaps()->fInfinitySupport);
	}
	auto* tessShader = GrPathTessellationShader::Make(*args.fCaps->shaderCaps(),
	args.fArena,
	shaderMatrix,
	SK_PMColor4fTRANSPARENT,
	fTessellator->patchAttribs());
	fStencilPathProgram = GrTessellationShader::MakeProgram(args,
	tessShader,
	stencilPipeline,
	stencilSettings);

	if (!(fPathFlags & FillPathFlags::kStencilOnly)) {
	// Create a program that draws a bounding box over the path and fills its stencil coverage
	// into the color buffer.
	auto* bboxShader = args.fArena->make<BoundingBoxShader>(fColor, *args.fCaps->shaderCaps());
	auto* bboxPipeline = GrTessellationShader::MakePipeline(args, fAAType,
	std::move(appliedClip),
	std::move(fProcessors));
	auto* bboxStencil = GrPathTessellationShader::TestAndResetStencilSettings(
	SkPathFillType_IsInverse(this->pathFillType()));
	fCoverBBoxProgram = GrSimpleMeshDrawOpHelper::CreateProgramInfo(
	args.fCaps,
	args.fArena,
	bboxPipeline,
	args.fWriteView,
	args.fUsesMSAASurface,
	bboxShader,
	GrPrimitiveType::kTriangleStrip,
	args.fXferBarrierFlags,
	args.fColorLoadOp,
	bboxStencil);
	}
	}

	void PathStencilCoverOp::onPrePrepare(GrRecordingContext* context,
	const GrSurfaceProxyView& writeView, GrAppliedClip* clip,
	const GrDstProxyView& dstProxyView,
	GrXferBarrierFlags renderPassXferBarriers,
	GrLoadOp colorLoadOp) {
	// DMSAA is not supported on DDL.
	bool usesMSAASurface = writeView.asRenderTargetProxy()->numSamples() > 1;
	this->prePreparePrograms({context->priv().recordTimeAllocator(), writeView, usesMSAASurface,
	&dstProxyView, renderPassXferBarriers, colorLoadOp,
	context->priv().caps()},
	(clip) ? std::move(*clip) : GrAppliedClip::Disabled());
	if (fStencilFanProgram) {
	context->priv().recordProgramInfo(fStencilFanProgram);
	}
	if (fStencilPathProgram) {
	context->priv().recordProgramInfo(fStencilPathProgram);
	}
	if (fCoverBBoxProgram) {
	context->priv().recordProgramInfo(fCoverBBoxProgram);
	}
	}

	SKGPU_DECLARE_STATIC_UNIQUE_KEY(gUnitQuadBufferKey);

	void PathStencilCoverOp::onPrepare(GrOpFlushState* flushState) {
	if (!fTessellator) {
	this->prePreparePrograms({flushState->allocator(), flushState->writeView(),
	flushState->usesMSAASurface(), &flushState->dstProxyView(),
	flushState->renderPassBarriers(), flushState->colorLoadOp(),
	&flushState->caps()}, flushState->detachAppliedClip());
	if (!fTessellator) {
	return;
	}
	}

	if (fStencilFanProgram) {
	// The inner fan isn't built into the tessellator. Generate a standard Redbook fan with a
	// middle-out topology.
	GrEagerDynamicVertexAllocator vertexAlloc(flushState, &fFanBuffer, &fFanBaseVertex);
	// Path fans might have an extra edge from an implicit kClose at the end, but they also
	// always begin with kMove. So the max possible number of edges in a single path is equal to
	// the number of verbs. Therefore, the max number of combined fan edges in a path list is
	// the number of combined verbs from the paths in the list.
	// A single n-sided polygon is fanned by n-2 triangles. Multiple polygons with a combined
	// edge count of n are fanned by strictly fewer triangles.
	int maxTrianglesInFans = std::max(fTotalCombinedPathVerbCnt - 2, 0);
	int fanTriangleCount = 0;
	if (VertexWriter triangleVertexWriter =
	vertexAlloc.lockWriter(sizeof(SkPoint), maxTrianglesInFans * 3)) {
	for (auto [pathMatrix, path, color] : *fPathDrawList) {
	tess::AffineMatrix m(pathMatrix);
	for (tess::PathMiddleOutFanIter it(path); !it.done();) {
	for (auto [p0, p1, p2] : it.nextStack()) {
	triangleVertexWriter << m.map2Points(p0, p1) << m.mapPoint(p2);
	++fanTriangleCount;
	}
	}
	}


	SkASSERT(fanTriangleCount <= maxTrianglesInFans);
	fFanVertexCount = fanTriangleCount * 3;
	vertexAlloc.unlock(fFanVertexCount);
	}
	}

	auto tessShader = &fStencilPathProgram->geomProc().cast<GrPathTessellationShader>();
	fTessellator->prepare(flushState,
	tessShader->viewMatrix(),
	*fPathDrawList,
	fTotalCombinedPathVerbCnt);

	if (fCoverBBoxProgram) {
	size_t instanceStride = fCoverBBoxProgram->geomProc().instanceStride();
	VertexWriter vertexWriter = flushState->makeVertexWriter(instanceStride,
	fPathCount,
	&fBBoxBuffer,
	&fBBoxBaseInstance);
	SkDEBUGCODE(int pathCount = 0;)
	for (auto [pathMatrix, path, color] : *fPathDrawList) {
	SkDEBUGCODE(auto end = vertexWriter.mark(instanceStride));
	vertexWriter << pathMatrix.getScaleX()
	<< pathMatrix.getSkewY()
	<< pathMatrix.getSkewX()
	<< pathMatrix.getScaleY()
	<< pathMatrix.getTranslateX()
	<< pathMatrix.getTranslateY();
	if (path.isInverseFillType()) {
	// Fill the entire backing store to make sure we clear every stencil value back to
	// 0. If there is a scissor it will have already clipped the stencil draw.
	auto rtBounds =
	flushState->writeView().asRenderTargetProxy()->backingStoreBoundsRect();
	SkASSERT(rtBounds == fOriginalDrawBounds);
	SkRect pathSpaceRTBounds;
	if (SkMatrixPriv::InverseMapRect(pathMatrix, &pathSpaceRTBounds, rtBounds)) {
	vertexWriter << pathSpaceRTBounds;
	} else {
	vertexWriter << path.getBounds();
	}
	} else {
	vertexWriter << path.getBounds();
	}
	SkASSERT(vertexWriter.mark() == end);
	SkDEBUGCODE(++pathCount;)
	}
	SkASSERT(pathCount == fPathCount);
	}

	if (!flushState->caps().shaderCaps()->fVertexIDSupport) {
	constexpr static SkPoint kUnitQuad[4] = {{0,0}, {0,1}, {1,0}, {1,1}};

	SKGPU_DEFINE_STATIC_UNIQUE_KEY(gUnitQuadBufferKey);

	fBBoxVertexBufferIfNoIDSupport = flushState->resourceProvider()->findOrMakeStaticBuffer(
	GrGpuBufferType::kVertex, sizeof(kUnitQuad), kUnitQuad, gUnitQuadBufferKey);
	}
	}

	void PathStencilCoverOp::onExecute(GrOpFlushState* flushState, const SkRect& chainBounds) {
	if (!fTessellator) {
	return;
	}

	if (fCoverBBoxProgram &&
	fCoverBBoxProgram->geomProc().hasVertexAttributes() &&
	!fBBoxVertexBufferIfNoIDSupport) {
	return;
	}

	// Stencil the inner fan, if any.
	if (fFanVertexCount > 0) {
	SkASSERT(fStencilFanProgram);
	SkASSERT(fFanBuffer);
	flushState->bindPipelineAndScissorClip(*fStencilFanProgram, this->bounds());
	flushState->bindBuffers(nullptr, nullptr, fFanBuffer);
	flushState->draw(fFanVertexCount, fFanBaseVertex);
	}

	// Stencil the rest of the path.
	SkASSERT(fStencilPathProgram);
	flushState->bindPipelineAndScissorClip(*fStencilPathProgram, this->bounds());
	fTessellator->draw(flushState);

	// Fill in the bounding box (if not in stencil-only mode).
	if (fCoverBBoxProgram) {
	flushState->bindPipelineAndScissorClip(*fCoverBBoxProgram, this->bounds());
	flushState->bindTextures(fCoverBBoxProgram->geomProc(), nullptr,
	fCoverBBoxProgram->pipeline());
	flushState->bindBuffers(nullptr, fBBoxBuffer, fBBoxVertexBufferIfNoIDSupport);
	flushState->drawInstanced(fPathCount, fBBoxBaseInstance, 4, 0);
	}
	}

	} // namespace skgpu::v1