1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
|
/*************************************************************************/
/* b2d_decompose.cpp */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2018 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2018 Godot Engine contributors (cf. AUTHORS.md) */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the */
/* "Software"), to deal in the Software without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of the Software, and to */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
/*************************************************************************/
#include "b2d_decompose.h"
#include "thirdparty/b2d_convexdecomp/b2Polygon.h"
namespace b2ConvexDecomp {
void add_to_res(Vector<Vector<Vector2> > &res, const b2Polygon &p_poly) {
Vector<Vector2> arr;
for (int i = 0; i < p_poly.nVertices; i++) {
arr.push_back(Vector2(p_poly.x[i], p_poly.y[i]));
}
res.push_back(arr);
}
static Vector<Vector<Vector2> > _b2d_decompose(const Vector<Vector2> &p_polygon) {
Vector<Vector<Vector2> > res;
if (p_polygon.size() < 3)
return res;
b2Vec2 *polys = memnew_arr(b2Vec2, p_polygon.size());
for (int i = 0; i < p_polygon.size(); i++)
polys[i] = b2Vec2(p_polygon[i].x, p_polygon[i].y);
b2Polygon *p = new b2Polygon(polys, p_polygon.size());
b2Polygon *decomposed = new b2Polygon[p->nVertices - 2]; //maximum number of polys
memdelete_arr(polys);
int32 nPolys = DecomposeConvex(p, decomposed, p->nVertices - 2);
//int32 extra = 0;
for (int32 i = 0; i < nPolys; ++i) {
// b2FixtureDef* toAdd = &pdarray[i+extra];
// *toAdd = *prototype;
//Hmm, shouldn't have to do all this...
b2Polygon curr = decomposed[i];
//TODO ewjordan: move this triangle handling to a better place so that
//it happens even if this convenience function is not called.
if (curr.nVertices == 3) {
//Check here for near-parallel edges, since we can't
//handle this in merge routine
for (int j = 0; j < 3; ++j) {
int32 lower = (j == 0) ? (curr.nVertices - 1) : (j - 1);
int32 middle = j;
int32 upper = (j == curr.nVertices - 1) ? (0) : (j + 1);
float32 dx0 = curr.x[middle] - curr.x[lower];
float32 dy0 = curr.y[middle] - curr.y[lower];
float32 dx1 = curr.x[upper] - curr.x[middle];
float32 dy1 = curr.y[upper] - curr.y[middle];
float32 norm0 = sqrtf(dx0 * dx0 + dy0 * dy0);
float32 norm1 = sqrtf(dx1 * dx1 + dy1 * dy1);
if (!(norm0 > 0.0f && norm1 > 0.0f)) {
//Identical points, don't do anything!
goto Skip;
}
dx0 /= norm0;
dy0 /= norm0;
dx1 /= norm1;
dy1 /= norm1;
float32 cross = dx0 * dy1 - dx1 * dy0;
float32 dot = dx0 * dx1 + dy0 * dy1;
if (fabs(cross) < b2_angularSlop && dot > 0) {
//Angle too close, split the triangle across from this point.
//This is guaranteed to result in two triangles that satify
//the tolerance (one of the angles is 90 degrees)
float32 dx2 = curr.x[lower] - curr.x[upper];
float32 dy2 = curr.y[lower] - curr.y[upper];
float32 norm2 = sqrtf(dx2 * dx2 + dy2 * dy2);
if (norm2 == 0.0f) {
goto Skip;
}
dx2 /= norm2;
dy2 /= norm2;
float32 thisArea = curr.GetArea();
float32 thisHeight = 2.0f * thisArea / norm2;
float32 buffer2 = dx2;
dx2 = dy2;
dy2 = -buffer2;
//Make two new polygons
//printf("dx2: %f, dy2: %f, thisHeight: %f, middle: %d\n",dx2,dy2,thisHeight,middle);
float32 newX1[3] = { curr.x[middle] + dx2 * thisHeight, curr.x[lower], curr.x[middle] };
float32 newY1[3] = { curr.y[middle] + dy2 * thisHeight, curr.y[lower], curr.y[middle] };
float32 newX2[3] = { newX1[0], curr.x[middle], curr.x[upper] };
float32 newY2[3] = { newY1[0], curr.y[middle], curr.y[upper] };
b2Polygon p1(newX1, newY1, 3);
b2Polygon p2(newX2, newY2, 3);
if (p1.IsUsable()) {
add_to_res(res, p1);
//++extra;
} else if (B2_POLYGON_REPORT_ERRORS) {
printf("Didn't add unusable polygon. Dumping vertices:\n");
p1.print();
}
if (p2.IsUsable()) {
add_to_res(res, p2);
//p2.AddTo(pdarray[i+extra]);
//bd->CreateFixture(toAdd);
} else if (B2_POLYGON_REPORT_ERRORS) {
printf("Didn't add unusable polygon. Dumping vertices:\n");
p2.print();
}
goto Skip;
}
}
}
if (decomposed[i].IsUsable()) {
add_to_res(res, decomposed[i]);
//decomposed[i].AddTo(*toAdd);
//bd->CreateFixture((const b2FixtureDef*)toAdd);
} else if (B2_POLYGON_REPORT_ERRORS) {
printf("Didn't add unusable polygon. Dumping vertices:\n");
decomposed[i].print();
}
Skip:;
}
//delete[] pdarray;
delete[] decomposed;
delete p;
return res; // pdarray; //needs to be deleted after body is created
}
} // namespace b2ConvexDecomp
Vector<Vector<Vector2> > b2d_decompose(const Vector<Vector2> &p_polygon) {
return b2ConvexDecomp::_b2d_decompose(p_polygon);
}
|