1/*
2 * Copyright 2020 Google LLC.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#ifndef GrStrokeTessellateOp_DEFINED
9#define GrStrokeTessellateOp_DEFINED
10
11#include "include/core/SkStrokeRec.h"
12#include "src/gpu/GrSTArenaList.h"
13#include "src/gpu/ops/GrDrawOp.h"
14#include "src/gpu/tessellate/GrStrokePatchBuilder.h"
15
16// Renders opaque, constant-color strokes by decomposing them into standalone tessellation patches.
17// Each patch is either a "cubic" (single stroked bezier curve with butt caps) or a "join". Requires
18// MSAA if antialiasing is desired.
19class GrStrokeTessellateOp : public GrDrawOp {
20public:
21 DEFINE_OP_CLASS_ID
22
23private:
24 // The provided matrix must be a similarity matrix for the time being. This is so we can
25 // bootstrap this Op on top of GrStrokeGeometry with minimal modifications.
26 //
27 // Patches can overlap, so until a stencil technique is implemented, the provided paint must be
28 // a constant blended color.
29 GrStrokeTessellateOp(GrAAType, const SkMatrix&, const SkPath&, const SkStrokeRec&, GrPaint&&);
30
31 const char* name() const override { return "GrStrokeTessellateOp"; }
32 void visitProxies(const VisitProxyFunc& fn) const override { fProcessors.visitProxies(fn); }
33 FixedFunctionFlags fixedFunctionFlags() const override;
34 GrProcessorSet::Analysis finalize(const GrCaps&, const GrAppliedClip*,
35 bool hasMixedSampledCoverage, GrClampType) override;
36 CombineResult onCombineIfPossible(GrOp*, GrRecordingContext::Arenas*, const GrCaps&) override;
37 void onPrePrepare(GrRecordingContext*, const GrSurfaceProxyView*, GrAppliedClip*,
38 const GrXferProcessor::DstProxyView&) override;
39 void onPrepare(GrOpFlushState* state) override;
40 void onExecute(GrOpFlushState*, const SkRect& chainBounds) override;
41
42 struct PathStroke {
43 PathStroke(const SkPath& path, const SkStrokeRec& stroke) : fPath(path), fStroke(stroke) {}
44 SkPath fPath;
45 SkStrokeRec fStroke;
46 };
47
48 GrSTArenaList<PathStroke> fPathStrokes;
49 int fTotalCombinedVerbCnt;
50
51 const GrAAType fAAType;
52 float fMatrixScale; // The matrix scale is applied to control points before tessellation.
53 SkMatrix fSkewMatrix; // The skew matrix is applied to the post-tessellation triangles.
54 float fMiterLimitOrZero = 0; // Zero if there is not a stroke with a miter join type.
55 SkPMColor4f fColor;
56 GrProcessorSet fProcessors;
57
58 // S=1 because we will almost always fit everything into one single chunk.
59 SkSTArray<1, GrStrokePatchBuilder::VertexChunk> fVertexChunks;
60
61 friend class GrOpMemoryPool; // For ctor.
62};
63
64#endif
65