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* Copyright 2019 Google LLC.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
#ifndef PathInnerTriangulateOp_DEFINED
#define PathInnerTriangulateOp_DEFINED
#include "src/gpu/geometry/GrInnerFanTriangulator.h"
#include "src/gpu/ops/FillPathFlags.h"
#include "src/gpu/ops/GrDrawOp.h"
#include "src/gpu/tessellate/shaders/GrTessellationShader.h"
namespace skgpu {
class PathCurveTessellator;
namespace skgpu::v1 {
// This op is a 3-pass twist on the standard Redbook "stencil then cover" algorithm:
// 1) Tessellate the path's outer curves into the stencil buffer.
// 2) Triangulate the path's inner fan and fill it with a stencil test against the curves.
// 3) Draw convex hulls around each curve that fill in remaining samples.
// In practice, a path's inner fan takes up a large majority of its pixels. So from a GPU load
// perspective, this op is effectively as fast as a single-pass algorithm.
class PathInnerTriangulateOp final : public GrDrawOp {
PathInnerTriangulateOp(const SkMatrix& viewMatrix,
const SkPath& path,
GrPaint&& paint,
GrAAType aaType,
FillPathFlags pathFlags,
const SkRect& drawBounds)
: GrDrawOp(ClassID())
, fPathFlags(pathFlags)
, fViewMatrix(viewMatrix)
, fPath(path)
, fAAType(aaType)
, fColor(paint.getColor4f())
, fProcessors(std::move(paint)) {
this->setBounds(drawBounds, HasAABloat::kNo, IsHairline::kNo);
const char* name() const override { return "PathInnerTriangulateOp"; }
void visitProxies(const GrVisitProxyFunc&) const override;
FixedFunctionFlags fixedFunctionFlags() const override;
GrProcessorSet::Analysis finalize(const GrCaps&, const GrAppliedClip*, GrClampType) override;
// These calls set up the stencil & fill programs we will use prior to preparing and executing.
void pushFanStencilProgram(const GrTessellationShader::ProgramArgs&,
const GrPipeline* pipelineForStencils, const GrUserStencilSettings*);
void pushFanFillProgram(const GrTessellationShader::ProgramArgs&, const GrUserStencilSettings*);
void prePreparePrograms(const GrTessellationShader::ProgramArgs&, GrAppliedClip&&);
void onPrePrepare(GrRecordingContext*, const GrSurfaceProxyView&, GrAppliedClip*,
const GrDstProxyView&, GrXferBarrierFlags, GrLoadOp colorLoadOp) override;
void onPrepare(GrOpFlushState*) override;
void onExecute(GrOpFlushState*, const SkRect& chainBounds) override;
const FillPathFlags fPathFlags;
const SkMatrix fViewMatrix;
const SkPath fPath;
const GrAAType fAAType;
SkPMColor4f fColor;
GrProcessorSet fProcessors;
// Triangulates the inner fan.
GrInnerFanTriangulator* fFanTriangulator = nullptr;
GrTriangulator::Poly* fFanPolys = nullptr;
GrInnerFanTriangulator::BreadcrumbTriangleList fFanBreadcrumbs;
// This pipeline is shared by all programs that do filling.
const GrPipeline* fPipelineForFills = nullptr;
// Tessellates the outer curves.
PathCurveTessellator* fTessellator = nullptr;
// Pass 1: Tessellate the outer curves into the stencil buffer.
const GrProgramInfo* fStencilCurvesProgram = nullptr;
// Pass 2: Fill the path's inner fan with a stencil test against the curves. (In extenuating
// circumstances this might require two separate draws.)
SkSTArray<2, const GrProgramInfo*> fFanPrograms;
// Pass 3: Draw convex hulls around each curve.
const GrProgramInfo* fCoverHullsProgram = nullptr;
// This buffer gets created by fFanTriangulator during onPrepare.
sk_sp<const GrBuffer> fFanBuffer;
int fBaseFanVertex = 0;
int fFanVertexCount = 0;
// Only used if sk_VertexID is not supported.
sk_sp<const GrGpuBuffer> fHullVertexBufferIfNoIDSupport;
friend class GrOp; // For ctor.
} // namespace skgpu::v1
#endif // PathInnerTriangulateOp_DEFINED