1 #ifndef BT_BASIC_GEOMETRY_OPERATIONS_H_INCLUDED
2 #define BT_BASIC_GEOMETRY_OPERATIONS_H_INCLUDED
3
4 /*! \file btGeometryOperations.h
5 *\author Francisco Leon Najera
6
7 */
8 /*
9 This source file is part of GIMPACT Library.
10
11 For the latest info, see http://gimpact.sourceforge.net/
12
13 Copyright (c) 2007 Francisco Leon Najera. C.C. 80087371.
14 email: projectileman@yahoo.com
15
16
17 This software is provided 'as-is', without any express or implied warranty.
18 In no event will the authors be held liable for any damages arising from the use of this software.
19 Permission is granted to anyone to use this software for any purpose,
20 including commercial applications, and to alter it and redistribute it freely,
21 subject to the following restrictions:
22
23 1. 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.
24 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
25 3. This notice may not be removed or altered from any source distribution.
26 */
27
28 #include "btBoxCollision.h"
29
30 #define PLANEDIREPSILON 0.0000001f
31 #define PARALELENORMALS 0.000001f
32
33 #define BT_CLAMP(number, minval, maxval) (number < minval ? minval : (number > maxval ? maxval : number))
34
35 /// Calc a plane from a triangle edge an a normal. plane is a vec4f
bt_edge_plane(const btVector3 & e1,const btVector3 & e2,const btVector3 & normal,btVector4 & plane)36 SIMD_FORCE_INLINE void bt_edge_plane(const btVector3 &e1, const btVector3 &e2, const btVector3 &normal, btVector4 &plane)
37 {
38 btVector3 planenormal = (e2 - e1).cross(normal);
39 planenormal.normalize();
40 plane.setValue(planenormal[0], planenormal[1], planenormal[2], e2.dot(planenormal));
41 }
42
43 //***************** SEGMENT and LINE FUNCTIONS **********************************///
44
45 /*! Finds the closest point(cp) to (v) on a segment (e1,e2)
46 */
bt_closest_point_on_segment(btVector3 & cp,const btVector3 & v,const btVector3 & e1,const btVector3 & e2)47 SIMD_FORCE_INLINE void bt_closest_point_on_segment(
48 btVector3 &cp, const btVector3 &v,
49 const btVector3 &e1, const btVector3 &e2)
50 {
51 btVector3 n = e2 - e1;
52 cp = v - e1;
53 btScalar _scalar = cp.dot(n) / n.dot(n);
54 if (_scalar < 0.0f)
55 {
56 cp = e1;
57 }
58 else if (_scalar > 1.0f)
59 {
60 cp = e2;
61 }
62 else
63 {
64 cp = _scalar * n + e1;
65 }
66 }
67
68 //! line plane collision
69 /*!
70 *\return
71 -0 if the ray never intersects
72 -1 if the ray collides in front
73 -2 if the ray collides in back
74 */
75
bt_line_plane_collision(const btVector4 & plane,const btVector3 & vDir,const btVector3 & vPoint,btVector3 & pout,btScalar & tparam,btScalar tmin,btScalar tmax)76 SIMD_FORCE_INLINE int bt_line_plane_collision(
77 const btVector4 &plane,
78 const btVector3 &vDir,
79 const btVector3 &vPoint,
80 btVector3 &pout,
81 btScalar &tparam,
82 btScalar tmin, btScalar tmax)
83 {
84 btScalar _dotdir = vDir.dot(plane);
85
86 if (btFabs(_dotdir) < PLANEDIREPSILON)
87 {
88 tparam = tmax;
89 return 0;
90 }
91
92 btScalar _dis = bt_distance_point_plane(plane, vPoint);
93 char returnvalue = _dis < 0.0f ? 2 : 1;
94 tparam = -_dis / _dotdir;
95
96 if (tparam < tmin)
97 {
98 returnvalue = 0;
99 tparam = tmin;
100 }
101 else if (tparam > tmax)
102 {
103 returnvalue = 0;
104 tparam = tmax;
105 }
106 pout = tparam * vDir + vPoint;
107 return returnvalue;
108 }
109
110 //! Find closest points on segments
bt_segment_collision(const btVector3 & vA1,const btVector3 & vA2,const btVector3 & vB1,const btVector3 & vB2,btVector3 & vPointA,btVector3 & vPointB)111 SIMD_FORCE_INLINE void bt_segment_collision(
112 const btVector3 &vA1,
113 const btVector3 &vA2,
114 const btVector3 &vB1,
115 const btVector3 &vB2,
116 btVector3 &vPointA,
117 btVector3 &vPointB)
118 {
119 btVector3 AD = vA2 - vA1;
120 btVector3 BD = vB2 - vB1;
121 btVector3 N = AD.cross(BD);
122 btScalar tp = N.length2();
123
124 btVector4 _M; //plane
125
126 if (tp < SIMD_EPSILON) //ARE PARALELE
127 {
128 //project B over A
129 bool invert_b_order = false;
130 _M[0] = vB1.dot(AD);
131 _M[1] = vB2.dot(AD);
132
133 if (_M[0] > _M[1])
134 {
135 invert_b_order = true;
136 BT_SWAP_NUMBERS(_M[0], _M[1]);
137 }
138 _M[2] = vA1.dot(AD);
139 _M[3] = vA2.dot(AD);
140 //mid points
141 N[0] = (_M[0] + _M[1]) * 0.5f;
142 N[1] = (_M[2] + _M[3]) * 0.5f;
143
144 if (N[0] < N[1])
145 {
146 if (_M[1] < _M[2])
147 {
148 vPointB = invert_b_order ? vB1 : vB2;
149 vPointA = vA1;
150 }
151 else if (_M[1] < _M[3])
152 {
153 vPointB = invert_b_order ? vB1 : vB2;
154 bt_closest_point_on_segment(vPointA, vPointB, vA1, vA2);
155 }
156 else
157 {
158 vPointA = vA2;
159 bt_closest_point_on_segment(vPointB, vPointA, vB1, vB2);
160 }
161 }
162 else
163 {
164 if (_M[3] < _M[0])
165 {
166 vPointB = invert_b_order ? vB2 : vB1;
167 vPointA = vA2;
168 }
169 else if (_M[3] < _M[1])
170 {
171 vPointA = vA2;
172 bt_closest_point_on_segment(vPointB, vPointA, vB1, vB2);
173 }
174 else
175 {
176 vPointB = invert_b_order ? vB1 : vB2;
177 bt_closest_point_on_segment(vPointA, vPointB, vA1, vA2);
178 }
179 }
180 return;
181 }
182
183 N = N.cross(BD);
184 _M.setValue(N[0], N[1], N[2], vB1.dot(N));
185
186 // get point A as the plane collision point
187 bt_line_plane_collision(_M, AD, vA1, vPointA, tp, btScalar(0), btScalar(1));
188
189 /*Closest point on segment*/
190 vPointB = vPointA - vB1;
191 tp = vPointB.dot(BD);
192 tp /= BD.dot(BD);
193 tp = BT_CLAMP(tp, 0.0f, 1.0f);
194
195 vPointB = tp * BD + vB1;
196 }
197
198 #endif // GIM_VECTOR_H_INCLUDED
199