1 #ifndef BT_BASIC_GEOMETRY_OPERATIONS_H_INCLUDED
2 #define BT_BASIC_GEOMETRY_OPERATIONS_H_INCLUDED
3
4 /*! \file btGeometryOperations.h
5 *\author Francisco Len N�jera
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
31
32
33
34 #define PLANEDIREPSILON 0.0000001f
35 #define PARALELENORMALS 0.000001f
36
37
38 #define BT_CLAMP(number,minval,maxval) (number<minval?minval:(number>maxval?maxval:number))
39
40 /// 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)41 SIMD_FORCE_INLINE void bt_edge_plane(const btVector3 & e1,const btVector3 & e2, const btVector3 & normal,btVector4 & plane)
42 {
43 btVector3 planenormal = (e2-e1).cross(normal);
44 planenormal.normalize();
45 plane.setValue(planenormal[0],planenormal[1],planenormal[2],e2.dot(planenormal));
46 }
47
48
49
50 //***************** SEGMENT and LINE FUNCTIONS **********************************///
51
52 /*! Finds the closest point(cp) to (v) on a segment (e1,e2)
53 */
bt_closest_point_on_segment(btVector3 & cp,const btVector3 & v,const btVector3 & e1,const btVector3 & e2)54 SIMD_FORCE_INLINE void bt_closest_point_on_segment(
55 btVector3 & cp, const btVector3 & v,
56 const btVector3 &e1,const btVector3 &e2)
57 {
58 btVector3 n = e2-e1;
59 cp = v - e1;
60 btScalar _scalar = cp.dot(n)/n.dot(n);
61 if(_scalar <0.0f)
62 {
63 cp = e1;
64 }
65 else if(_scalar >1.0f)
66 {
67 cp = e2;
68 }
69 else
70 {
71 cp = _scalar*n + e1;
72 }
73 }
74
75
76 //! line plane collision
77 /*!
78 *\return
79 -0 if the ray never intersects
80 -1 if the ray collides in front
81 -2 if the ray collides in back
82 */
83
bt_line_plane_collision(const btVector4 & plane,const btVector3 & vDir,const btVector3 & vPoint,btVector3 & pout,btScalar & tparam,btScalar tmin,btScalar tmax)84 SIMD_FORCE_INLINE int bt_line_plane_collision(
85 const btVector4 & plane,
86 const btVector3 & vDir,
87 const btVector3 & vPoint,
88 btVector3 & pout,
89 btScalar &tparam,
90 btScalar tmin, btScalar tmax)
91 {
92
93 btScalar _dotdir = vDir.dot(plane);
94
95 if(btFabs(_dotdir)<PLANEDIREPSILON)
96 {
97 tparam = tmax;
98 return 0;
99 }
100
101 btScalar _dis = bt_distance_point_plane(plane,vPoint);
102 char returnvalue = _dis<0.0f? 2:1;
103 tparam = -_dis/_dotdir;
104
105 if(tparam<tmin)
106 {
107 returnvalue = 0;
108 tparam = tmin;
109 }
110 else if(tparam>tmax)
111 {
112 returnvalue = 0;
113 tparam = tmax;
114 }
115 pout = tparam*vDir + vPoint;
116 return returnvalue;
117 }
118
119
120 //! Find closest points on segments
bt_segment_collision(const btVector3 & vA1,const btVector3 & vA2,const btVector3 & vB1,const btVector3 & vB2,btVector3 & vPointA,btVector3 & vPointB)121 SIMD_FORCE_INLINE void bt_segment_collision(
122 const btVector3 & vA1,
123 const btVector3 & vA2,
124 const btVector3 & vB1,
125 const btVector3 & vB2,
126 btVector3 & vPointA,
127 btVector3 & vPointB)
128 {
129 btVector3 AD = vA2 - vA1;
130 btVector3 BD = vB2 - vB1;
131 btVector3 N = AD.cross(BD);
132 btScalar tp = N.length2();
133
134 btVector4 _M;//plane
135
136 if(tp<SIMD_EPSILON)//ARE PARALELE
137 {
138 //project B over A
139 bool invert_b_order = false;
140 _M[0] = vB1.dot(AD);
141 _M[1] = vB2.dot(AD);
142
143 if(_M[0]>_M[1])
144 {
145 invert_b_order = true;
146 BT_SWAP_NUMBERS(_M[0],_M[1]);
147 }
148 _M[2] = vA1.dot(AD);
149 _M[3] = vA2.dot(AD);
150 //mid points
151 N[0] = (_M[0]+_M[1])*0.5f;
152 N[1] = (_M[2]+_M[3])*0.5f;
153
154 if(N[0]<N[1])
155 {
156 if(_M[1]<_M[2])
157 {
158 vPointB = invert_b_order?vB1:vB2;
159 vPointA = vA1;
160 }
161 else if(_M[1]<_M[3])
162 {
163 vPointB = invert_b_order?vB1:vB2;
164 bt_closest_point_on_segment(vPointA,vPointB,vA1,vA2);
165 }
166 else
167 {
168 vPointA = vA2;
169 bt_closest_point_on_segment(vPointB,vPointA,vB1,vB2);
170 }
171 }
172 else
173 {
174 if(_M[3]<_M[0])
175 {
176 vPointB = invert_b_order?vB2:vB1;
177 vPointA = vA2;
178 }
179 else if(_M[3]<_M[1])
180 {
181 vPointA = vA2;
182 bt_closest_point_on_segment(vPointB,vPointA,vB1,vB2);
183 }
184 else
185 {
186 vPointB = invert_b_order?vB1:vB2;
187 bt_closest_point_on_segment(vPointA,vPointB,vA1,vA2);
188 }
189 }
190 return;
191 }
192
193 N = N.cross(BD);
194 _M.setValue(N[0],N[1],N[2],vB1.dot(N));
195
196 // get point A as the plane collision point
197 bt_line_plane_collision(_M,AD,vA1,vPointA,tp,btScalar(0), btScalar(1));
198
199 /*Closest point on segment*/
200 vPointB = vPointA - vB1;
201 tp = vPointB.dot(BD);
202 tp/= BD.dot(BD);
203 tp = BT_CLAMP(tp,0.0f,1.0f);
204
205 vPointB = tp*BD + vB1;
206 }
207
208
209
210
211
212 #endif // GIM_VECTOR_H_INCLUDED
213