Bullet Collision Detection & Physics Library: btTriangleShapeEx.cpp Source File

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btTriangleShapeEx.cpp
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1
4/*
5This source file is part of GIMPACT Library.
6
7For the latest info, see http://gimpact.sourceforge.net/
8
9Copyright (c) 2007 Francisco Leon Najera. C.C. 80087371.
10email: projectileman@yahoo.com
11
12
13This software is provided 'as-is', without any express or implied warranty.
14In no event will the authors be held liable for any damages arising from the use of this software.
15Permission is granted to anyone to use this software for any purpose,
16including commercial applications, and to alter it and redistribute it freely,
17subject to the following restrictions:
18
191. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
202. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
213. This notice may not be removed or altered from any source distribution.
22*/
23
24#include "btTriangleShapeEx.h"
25
26 void GIM_TRIANGLE_CONTACT::merge_points(const btVector4& plane,
27 btScalar margin, const btVector3* points, int point_count)
28{
29 m_point_count = 0;
30 m_penetration_depth = -1000.0f;
31
32 int point_indices[MAX_TRI_CLIPPING];
33
34 int _k;
35
36 for (_k = 0; _k < point_count; _k++)
37 {
38 btScalar _dist = -bt_distance_point_plane(plane, points[_k]) + margin;
39
40 if (_dist >= 0.0f)
41 {
42 if (_dist > m_penetration_depth)
43 {
44 m_penetration_depth = _dist;
45 point_indices[0] = _k;
46 m_point_count = 1;
47 }
48 else if ((_dist + SIMD_EPSILON) >= m_penetration_depth)
49 {
50 point_indices[m_point_count] = _k;
51 m_point_count++;
52 }
53 }
54 }
55
56 for (_k = 0; _k < m_point_count; _k++)
57 {
58 m_points[_k] = points[point_indices[_k]];
59 }
60}
61
63 bool btPrimitiveTriangle::overlap_test_conservative(const btPrimitiveTriangle& other)
64{
65 btScalar total_margin = m_margin + other.m_margin;
66 // classify points on other triangle
67 btScalar dis0 = bt_distance_point_plane(m_plane, other.m_vertices[0]) - total_margin;
68
69 btScalar dis1 = bt_distance_point_plane(m_plane, other.m_vertices[1]) - total_margin;
70
71 btScalar dis2 = bt_distance_point_plane(m_plane, other.m_vertices[2]) - total_margin;
72
73 if (dis0 > 0.0f && dis1 > 0.0f && dis2 > 0.0f) return false;
74
75 // classify points on this triangle
76 dis0 = bt_distance_point_plane(other.m_plane, m_vertices[0]) - total_margin;
77
78 dis1 = bt_distance_point_plane(other.m_plane, m_vertices[1]) - total_margin;
79
80 dis2 = bt_distance_point_plane(other.m_plane, m_vertices[2]) - total_margin;
81
82 if (dis0 > 0.0f && dis1 > 0.0f && dis2 > 0.0f) return false;
83
84 return true;
85}
86
87 int btPrimitiveTriangle::clip_triangle(btPrimitiveTriangle& other, btVector3* clipped_points)
88{
89 // edge 0
90
91 btVector3 temp_points[MAX_TRI_CLIPPING];
92
93 btVector4 edgeplane;
94
95 get_edge_plane(0, edgeplane);
96
97 int clipped_count = bt_plane_clip_triangle(
98 edgeplane, other.m_vertices[0], other.m_vertices[1], other.m_vertices[2], temp_points);
99
100 if (clipped_count == 0) return 0;
101
102 btVector3 temp_points1[MAX_TRI_CLIPPING];
103
104 // edge 1
105 get_edge_plane(1, edgeplane);
106
107 clipped_count = bt_plane_clip_polygon(edgeplane, temp_points, clipped_count, temp_points1);
108
109 if (clipped_count == 0) return 0;
110
111 // edge 2
112 get_edge_plane(2, edgeplane);
113
114 clipped_count = bt_plane_clip_polygon(
115 edgeplane, temp_points1, clipped_count, clipped_points);
116
117 return clipped_count;
118}
119
120 bool btPrimitiveTriangle::find_triangle_collision_clip_method(btPrimitiveTriangle& other, GIM_TRIANGLE_CONTACT& contacts)
121{
122 btScalar margin = m_margin + other.m_margin;
123
124 btVector3 clipped_points[MAX_TRI_CLIPPING];
125 int clipped_count;
126 //create planes
127 // plane v vs U points
128
129 GIM_TRIANGLE_CONTACT contacts1;
130
131 contacts1.m_separating_normal = m_plane;
132
133 clipped_count = clip_triangle(other, clipped_points);
134
135 if (clipped_count == 0)
136 {
137 return false; //Reject
138 }
139
140 //find most deep interval face1
141 contacts1.merge_points(contacts1.m_separating_normal, margin, clipped_points, clipped_count);
142 if (contacts1.m_point_count == 0) return false; // too far
143 //Normal pointing to this triangle
144 contacts1.m_separating_normal *= -1.f;
145
146 //Clip tri1 by tri2 edges
147 GIM_TRIANGLE_CONTACT contacts2;
148 contacts2.m_separating_normal = other.m_plane;
149
150 clipped_count = other.clip_triangle(*this, clipped_points);
151
152 if (clipped_count == 0)
153 {
154 return false; //Reject
155 }
156
157 //find most deep interval face1
158 contacts2.merge_points(contacts2.m_separating_normal, margin, clipped_points, clipped_count);
159 if (contacts2.m_point_count == 0) return false; // too far
160
162 if (contacts2.m_penetration_depth < contacts1.m_penetration_depth)
163 {
164 contacts.copy_from(contacts2);
165 }
166 else
167 {
168 contacts.copy_from(contacts1);
169 }
170 return true;
171}
172
174
175 bool btTriangleShapeEx::overlap_test_conservative(const btTriangleShapeEx& other)
176{
177 btScalar total_margin = getMargin() + other.getMargin();
178
179 btVector4 plane0;
180 buildTriPlane(plane0);
181 btVector4 plane1;
182 other.buildTriPlane(plane1);
183
184 // classify points on other triangle
185 btScalar dis0 = bt_distance_point_plane(plane0, other.m_vertices1[0]) - total_margin;
186
187 btScalar dis1 = bt_distance_point_plane(plane0, other.m_vertices1[1]) - total_margin;
188
189 btScalar dis2 = bt_distance_point_plane(plane0, other.m_vertices1[2]) - total_margin;
190
191 if (dis0 > 0.0f && dis1 > 0.0f && dis2 > 0.0f) return false;
192
193 // classify points on this triangle
194 dis0 = bt_distance_point_plane(plane1, m_vertices1[0]) - total_margin;
195
196 dis1 = bt_distance_point_plane(plane1, m_vertices1[1]) - total_margin;
197
198 dis2 = bt_distance_point_plane(plane1, m_vertices1[2]) - total_margin;
199
200 if (dis0 > 0.0f && dis1 > 0.0f && dis2 > 0.0f) return false;
201
202 return true;
203}
bt_plane_clip_triangle
int bt_plane_clip_triangle(const btVector4 &plane, const btVector3 &point0, const btVector3 &point1, const btVector3 &point2, btVector3 *clipped)
Clips a polygon by a plane.
Definition: btClipPolygon.h:119
bt_distance_point_plane
btScalar bt_distance_point_plane(const btVector4 &plane, const btVector3 &point)
Definition: btClipPolygon.h:30
bt_plane_clip_polygon
int bt_plane_clip_polygon(const btVector4 &plane, const btVector3 *polygon_points, int polygon_point_count, btVector3 *clipped)
Clips a polygon by a plane.
Definition: btClipPolygon.h:70
btScalar
float btScalar
The btScalar type abstracts floating point numbers, to easily switch between double and single floati...
Definition: btScalar.h:314
SIMD_EPSILON
#define SIMD_EPSILON
Definition: btScalar.h:543
btTriangleShapeEx.h
MAX_TRI_CLIPPING
#define MAX_TRI_CLIPPING
Definition: btTriangleShapeEx.h:33
btConvexInternalShape::getMargin
virtual btScalar getMargin() const
Definition: btConvexInternalShape.h:106
btPrimitiveTriangle
Definition: btTriangleShapeEx.h:70
btPrimitiveTriangle::find_triangle_collision_clip_method
bool find_triangle_collision_clip_method(btPrimitiveTriangle &other, GIM_TRIANGLE_CONTACT &contacts)
Find collision using the clipping method.
Definition: btTriangleShapeEx.cpp:120
btPrimitiveTriangle::m_vertices
btVector3 m_vertices[3]
Definition: btTriangleShapeEx.h:72
btPrimitiveTriangle::clip_triangle
int clip_triangle(btPrimitiveTriangle &other, btVector3 *clipped_points)
Clips the triangle against this.
Definition: btTriangleShapeEx.cpp:87
btPrimitiveTriangle::get_edge_plane
void get_edge_plane(int edge_index, btVector4 &plane) const
Calcs the plane which is paralele to the edge and perpendicular to the triangle plane.
Definition: btTriangleShapeEx.h:94
btPrimitiveTriangle::m_margin
btScalar m_margin
Definition: btTriangleShapeEx.h:74
btPrimitiveTriangle::overlap_test_conservative
bool overlap_test_conservative(const btPrimitiveTriangle &other)
Test if triangles could collide.
Definition: btTriangleShapeEx.cpp:63
btPrimitiveTriangle::m_plane
btVector4 m_plane
Definition: btTriangleShapeEx.h:73
btTriangleShapeEx
Helper class for colliding Bullet Triangle Shapes.
Definition: btTriangleShapeEx.h:127
btTriangleShapeEx::overlap_test_conservative
bool overlap_test_conservative(const btTriangleShapeEx &other)
class btTriangleShapeEx: public btTriangleShape
Definition: btTriangleShapeEx.cpp:175
btTriangleShapeEx::buildTriPlane
void buildTriPlane(btVector4 &plane) const
Definition: btTriangleShapeEx.h:159
btTriangleShape::m_vertices1
btVector3 m_vertices1[3]
Definition: btTriangleShape.h:28
btVector3
btVector3 can be used to represent 3D points and vectors.
Definition: btVector3.h:82
btVector4
Definition: btVector3.h:1074
GIM_TRIANGLE_CONTACT
Structure for collision.
Definition: btTriangleShapeEx.h:37
GIM_TRIANGLE_CONTACT::m_points
btVector3 m_points[MAX_TRI_CLIPPING]
Definition: btTriangleShapeEx.h:41
GIM_TRIANGLE_CONTACT::m_penetration_depth
btScalar m_penetration_depth
Definition: btTriangleShapeEx.h:38
GIM_TRIANGLE_CONTACT::copy_from
void copy_from(const GIM_TRIANGLE_CONTACT &other)
Definition: btTriangleShapeEx.h:43
GIM_TRIANGLE_CONTACT::m_separating_normal
btVector4 m_separating_normal
Definition: btTriangleShapeEx.h:40
GIM_TRIANGLE_CONTACT::merge_points
void merge_points(const btVector4 &plane, btScalar margin, const btVector3 *points, int point_count)
classify points that are closer
Definition: btTriangleShapeEx.cpp:26
GIM_TRIANGLE_CONTACT::m_point_count
int m_point_count
Definition: btTriangleShapeEx.h:39