Bullet Collision Detection & Physics Library
btCapsuleShape.cpp
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1 /*
2 Bullet Continuous Collision Detection and Physics Library
3 Copyright (c) 2003-2009 Erwin Coumans http://bulletphysics.org
4 
5 This software is provided 'as-is', without any express or implied warranty.
6 In no event will the authors be held liable for any damages arising from the use of this software.
7 Permission is granted to anyone to use this software for any purpose,
8 including commercial applications, and to alter it and redistribute it freely,
9 subject to the following restrictions:
10 
11 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.
12 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
13 3. This notice may not be removed or altered from any source distribution.
14 */
15 
16 
17 #include "btCapsuleShape.h"
18 
20 
22 {
23  m_collisionMargin = radius;
25  m_upAxis = 1;
26  m_implicitShapeDimensions.setValue(radius,0.5f*height,radius);
27 }
28 
29 
31 {
32 
33  btVector3 supVec(0,0,0);
34 
36 
37  btVector3 vec = vec0;
38  btScalar lenSqr = vec.length2();
39  if (lenSqr < btScalar(0.0001))
40  {
41  vec.setValue(1,0,0);
42  } else
43  {
44  btScalar rlen = btScalar(1.) / btSqrt(lenSqr );
45  vec *= rlen;
46  }
47 
48  btVector3 vtx;
49  btScalar newDot;
50 
51 
52 
53  {
54  btVector3 pos(0,0,0);
55  pos[getUpAxis()] = getHalfHeight();
56 
57  vtx = pos;
58  newDot = vec.dot(vtx);
59  if (newDot > maxDot)
60  {
61  maxDot = newDot;
62  supVec = vtx;
63  }
64  }
65  {
66  btVector3 pos(0,0,0);
67  pos[getUpAxis()] = -getHalfHeight();
68 
69  vtx = pos;
70  newDot = vec.dot(vtx);
71  if (newDot > maxDot)
72  {
73  maxDot = newDot;
74  supVec = vtx;
75  }
76  }
77 
78  return supVec;
79 
80 }
81 
82  void btCapsuleShape::batchedUnitVectorGetSupportingVertexWithoutMargin(const btVector3* vectors,btVector3* supportVerticesOut,int numVectors) const
83 {
84 
85 
86 
87  for (int j=0;j<numVectors;j++)
88  {
90  const btVector3& vec = vectors[j];
91 
92  btVector3 vtx;
93  btScalar newDot;
94  {
95  btVector3 pos(0,0,0);
96  pos[getUpAxis()] = getHalfHeight();
97  vtx = pos;
98  newDot = vec.dot(vtx);
99  if (newDot > maxDot)
100  {
101  maxDot = newDot;
102  supportVerticesOut[j] = vtx;
103  }
104  }
105  {
106  btVector3 pos(0,0,0);
107  pos[getUpAxis()] = -getHalfHeight();
108  vtx = pos;
109  newDot = vec.dot(vtx);
110  if (newDot > maxDot)
111  {
112  maxDot = newDot;
113  supportVerticesOut[j] = vtx;
114  }
115  }
116 
117  }
118 }
119 
120 
122 {
123  //as an approximation, take the inertia of the box that bounds the spheres
124 
125  btTransform ident;
126  ident.setIdentity();
127 
128 
129  btScalar radius = getRadius();
130 
131  btVector3 halfExtents(radius,radius,radius);
132  halfExtents[getUpAxis()]+=getHalfHeight();
133 
134  btScalar lx=btScalar(2.)*(halfExtents[0]);
135  btScalar ly=btScalar(2.)*(halfExtents[1]);
136  btScalar lz=btScalar(2.)*(halfExtents[2]);
137  const btScalar x2 = lx*lx;
138  const btScalar y2 = ly*ly;
139  const btScalar z2 = lz*lz;
140  const btScalar scaledmass = mass * btScalar(.08333333);
141 
142  inertia[0] = scaledmass * (y2+z2);
143  inertia[1] = scaledmass * (x2+z2);
144  inertia[2] = scaledmass * (x2+y2);
145 
146 }
147 
149 {
150  m_collisionMargin = radius;
151  m_upAxis = 0;
152  m_implicitShapeDimensions.setValue(0.5f*height, radius,radius);
153 }
154 
155 
156 
157 
158 
159 
161 {
162  m_collisionMargin = radius;
163  m_upAxis = 2;
164  m_implicitShapeDimensions.setValue(radius,radius,0.5f*height);
165 }
166 
167 
168 
169 
btCapsuleShapeX(btScalar radius, btScalar height)
#define BT_LARGE_FLOAT
Definition: btScalar.h:294
void setValue(const btScalar &_x, const btScalar &_y, const btScalar &_z)
Definition: btVector3.h:652
The btConvexInternalShape is an internal base class, shared by most convex shape implementations.
btScalar btSqrt(btScalar y)
Definition: btScalar.h:444
void setIdentity()
Set this transformation to the identity.
Definition: btTransform.h:172
btScalar getRadius() const
int getUpAxis() const
btScalar dot(const btVector3 &v) const
Return the dot product.
Definition: btVector3.h:235
btCapsuleShapeZ(btScalar radius, btScalar height)
virtual void calculateLocalInertia(btScalar mass, btVector3 &inertia) const
CollisionShape Interface.
btCapsuleShape()
only used for btCapsuleShapeZ and btCapsuleShapeX subclasses.
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
The btTransform class supports rigid transforms with only translation and rotation and no scaling/she...
Definition: btTransform.h:34
virtual void batchedUnitVectorGetSupportingVertexWithoutMargin(const btVector3 *vectors, btVector3 *supportVerticesOut, int numVectors) const
virtual btVector3 localGetSupportingVertexWithoutMargin(const btVector3 &vec) const
btConvexShape Interface
btScalar getHalfHeight() const
float btScalar
The btScalar type abstracts floating point numbers, to easily switch between double and single floati...
Definition: btScalar.h:292