Bullet Collision Detection & Physics Library
btGeometryOperations.h
Go to the documentation of this file.
1 #ifndef BT_BASIC_GEOMETRY_OPERATIONS_H_INCLUDED
2 #define BT_BASIC_GEOMETRY_OPERATIONS_H_INCLUDED
3 
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 
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 
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 
77 
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 
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
#define SIMD_EPSILON
Definition: btScalar.h:448
void bt_edge_plane(const btVector3 &e1, const btVector3 &e2, const btVector3 &normal, btVector4 &plane)
Calc a plane from a triangle edge an a normal. plane is a vec4f.
int bt_line_plane_collision(const btVector4 &plane, const btVector3 &vDir, const btVector3 &vPoint, btVector3 &pout, btScalar &tparam, btScalar tmin, btScalar tmax)
line plane collision
#define SIMD_FORCE_INLINE
Definition: btScalar.h:58
btScalar dot(const btVector3 &v) const
Return the dot product.
Definition: btVector3.h:235
btVector3 & normalize()
Normalize this vector x^2 + y^2 + z^2 = 1.
Definition: btVector3.h:297
#define BT_CLAMP(number, minval, maxval)
#define PLANEDIREPSILON
btScalar bt_distance_point_plane(const btVector4 &plane, const btVector3 &point)
Definition: btClipPolygon.h:31
void bt_segment_collision(const btVector3 &vA1, const btVector3 &vA2, const btVector3 &vB1, const btVector3 &vB2, btVector3 &vPointA, btVector3 &vPointB)
Find closest points on segments.
btVector3 cross(const btVector3 &v) const
Return the cross product between this and another vector.
Definition: btVector3.h:377
btVector3 can be used to represent 3D points and vectors.
Definition: btVector3.h:83
btScalar length2() const
Return the length of the vector squared.
Definition: btVector3.h:257
void bt_closest_point_on_segment(btVector3 &cp, const btVector3 &v, const btVector3 &e1, const btVector3 &e2)
static float4 cross(const float4 &a, const float4 &b)
#define BT_SWAP_NUMBERS(a, b)
Swap numbers.
float btScalar
The btScalar type abstracts floating point numbers, to easily switch between double and single floati...
Definition: btScalar.h:266
void setValue(const btScalar &_x, const btScalar &_y, const btScalar &_z, const btScalar &_w)
Set x,y,z and zero w.
Definition: btVector3.h:1213
btScalar btFabs(btScalar x)
Definition: btScalar.h:407