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 
21 
23 {
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  btScalar radius = getRadius();
52 
53 
54  {
55  btVector3 pos(0,0,0);
56  pos[getUpAxis()] = getHalfHeight();
57 
58  vtx = pos +vec*(radius) - vec * getMargin();
59  newDot = vec.dot(vtx);
60  if (newDot > maxDot)
61  {
62  maxDot = newDot;
63  supVec = vtx;
64  }
65  }
66  {
67  btVector3 pos(0,0,0);
68  pos[getUpAxis()] = -getHalfHeight();
69 
70  vtx = pos +vec*(radius) - vec * getMargin();
71  newDot = vec.dot(vtx);
72  if (newDot > maxDot)
73  {
74  maxDot = newDot;
75  supVec = vtx;
76  }
77  }
78 
79  return supVec;
80 
81 }
82 
83  void btCapsuleShape::batchedUnitVectorGetSupportingVertexWithoutMargin(const btVector3* vectors,btVector3* supportVerticesOut,int numVectors) const
84 {
85 
86 
87  btScalar radius = getRadius();
88 
89  for (int j=0;j<numVectors;j++)
90  {
92  const btVector3& vec = vectors[j];
93 
94  btVector3 vtx;
95  btScalar newDot;
96  {
97  btVector3 pos(0,0,0);
98  pos[getUpAxis()] = getHalfHeight();
99  vtx = pos +vec*(radius) - vec * getMargin();
100  newDot = vec.dot(vtx);
101  if (newDot > maxDot)
102  {
103  maxDot = newDot;
104  supportVerticesOut[j] = vtx;
105  }
106  }
107  {
108  btVector3 pos(0,0,0);
109  pos[getUpAxis()] = -getHalfHeight();
110  vtx = pos +vec*(radius) - vec * getMargin();
111  newDot = vec.dot(vtx);
112  if (newDot > maxDot)
113  {
114  maxDot = newDot;
115  supportVerticesOut[j] = vtx;
116  }
117  }
118 
119  }
120 }
121 
122 
124 {
125  //as an approximation, take the inertia of the box that bounds the spheres
126 
127  btTransform ident;
128  ident.setIdentity();
129 
130 
131  btScalar radius = getRadius();
132 
133  btVector3 halfExtents(radius,radius,radius);
134  halfExtents[getUpAxis()]+=getHalfHeight();
135 
137 
138  btScalar lx=btScalar(2.)*(halfExtents[0]+margin);
139  btScalar ly=btScalar(2.)*(halfExtents[1]+margin);
140  btScalar lz=btScalar(2.)*(halfExtents[2]+margin);
141  const btScalar x2 = lx*lx;
142  const btScalar y2 = ly*ly;
143  const btScalar z2 = lz*lz;
144  const btScalar scaledmass = mass * btScalar(.08333333);
145 
146  inertia[0] = scaledmass * (y2+z2);
147  inertia[1] = scaledmass * (x2+z2);
148  inertia[2] = scaledmass * (x2+y2);
149 
150 }
151 
153 {
154  m_upAxis = 0;
155  m_implicitShapeDimensions.setValue(0.5f*height, radius,radius);
156 }
157 
158 
159 
160 
161 
162 
164 {
165  m_upAxis = 2;
166  m_implicitShapeDimensions.setValue(radius,radius,0.5f*height);
167 }
168 
169 
170 
171 
btCapsuleShapeX(btScalar radius, btScalar height)
#define BT_LARGE_FLOAT
Definition: btScalar.h:280
#define CONVEX_DISTANCE_MARGIN
The CONVEX_DISTANCE_MARGIN is a default collision margin for convex collision shapes derived from btC...
void setValue(const btScalar &_x, const btScalar &_y, const btScalar &_z)
Definition: btVector3.h:640
The btConvexInternalShape is an internal base class, shared by most convex shape implementations.
btScalar btSqrt(btScalar y)
Definition: btScalar.h:418
void setIdentity()
Set this transformation to the identity.
Definition: btTransform.h:172
btScalar getRadius() const
int getUpAxis() const
virtual btScalar getMargin() const
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:278