1 /*
2 * Copyright 2015 Google Inc.
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 GrTessellator_DEFINED
9 #define GrTessellator_DEFINED
10
11 #include "include/core/SkPoint.h"
12 #include "include/private/SkColorData.h"
13 #include "src/gpu/GrColor.h"
14
15 class GrEagerVertexAllocator;
16 class SkPath;
17 struct SkRect;
18
19 /**
20 * Provides utility functions for converting paths to a collection of triangles.
21 */
22
23 #define TESSELLATOR_WIREFRAME 0
24
25 namespace GrTessellator {
26
27 struct WindingVertex {
28 SkPoint fPos;
29 int fWinding;
30 };
31
32 // Triangulates a path to an array of vertices. Each triangle is represented as a set of three
33 // WindingVertex entries, each of which contains the position and winding count (which is the same
34 // for all three vertices of a triangle). The 'verts' out parameter is set to point to the resultant
35 // vertex array. CALLER IS RESPONSIBLE for deleting this buffer to avoid a memory leak!
36 int PathToVertices(const SkPath& path, SkScalar tolerance, const SkRect& clipBounds,
37 WindingVertex** verts);
38
39 enum class Mode {
40 kNormal,
41
42 // Surround path edges with coverage ramps for antialiasing.
43 kEdgeAntialias,
44
45 // Tessellate only each contour's inner polygon. The inner polygons connect the endpoints of
46 // each verb. (i.e., they are the path that would result from collapsing all curves to single
47 // lines.)
48 //
49 // If the inner polygons are not simple (e.g., self intersection, double winding), then the
50 // tessellator aborts and returns 0.
51 kSimpleInnerPolygons
52 };
53
GetVertexStride(Mode mode)54 constexpr size_t GetVertexStride(Mode mode) {
55 return sizeof(SkPoint) + ((Mode::kEdgeAntialias == mode) ? sizeof(float) : 0);
56 }
57
58 int PathToTriangles(const SkPath& path, SkScalar tolerance, const SkRect& clipBounds,
59 GrEagerVertexAllocator*, Mode, bool *isLinear);
60 }
61
62 #endif
63