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 #include "btCapsuleShape.h"
17 
19 
21 {
22  m_collisionMargin = radius;
24  m_upAxis = 1;
25  m_implicitShapeDimensions.setValue(radius, 0.5f * height, radius);
26 }
27 
29 {
30  btVector3 supVec(0, 0, 0);
31 
33 
34  btVector3 vec = vec0;
35  btScalar lenSqr = vec.length2();
36  if (lenSqr < btScalar(0.0001))
37  {
38  vec.setValue(1, 0, 0);
39  }
40  else
41  {
42  btScalar rlen = btScalar(1.) / btSqrt(lenSqr);
43  vec *= rlen;
44  }
45 
46  btVector3 vtx;
47  btScalar newDot;
48 
49  {
50  btVector3 pos(0, 0, 0);
51  pos[getUpAxis()] = getHalfHeight();
52 
53  vtx = pos;
54  newDot = vec.dot(vtx);
55  if (newDot > maxDot)
56  {
57  maxDot = newDot;
58  supVec = vtx;
59  }
60  }
61  {
62  btVector3 pos(0, 0, 0);
63  pos[getUpAxis()] = -getHalfHeight();
64 
65  vtx = pos;
66  newDot = vec.dot(vtx);
67  if (newDot > maxDot)
68  {
69  maxDot = newDot;
70  supVec = vtx;
71  }
72  }
73 
74  return supVec;
75 }
76 
77 void btCapsuleShape::batchedUnitVectorGetSupportingVertexWithoutMargin(const btVector3* vectors, btVector3* supportVerticesOut, int numVectors) const
78 {
79  for (int j = 0; j < numVectors; j++)
80  {
82  const btVector3& vec = vectors[j];
83 
84  btVector3 vtx;
85  btScalar newDot;
86  {
87  btVector3 pos(0, 0, 0);
88  pos[getUpAxis()] = getHalfHeight();
89  vtx = pos;
90  newDot = vec.dot(vtx);
91  if (newDot > maxDot)
92  {
93  maxDot = newDot;
94  supportVerticesOut[j] = vtx;
95  }
96  }
97  {
98  btVector3 pos(0, 0, 0);
99  pos[getUpAxis()] = -getHalfHeight();
100  vtx = pos;
101  newDot = vec.dot(vtx);
102  if (newDot > maxDot)
103  {
104  maxDot = newDot;
105  supportVerticesOut[j] = vtx;
106  }
107  }
108  }
109 }
110 
112 {
113  //as an approximation, take the inertia of the box that bounds the spheres
114 
115  btTransform ident;
116  ident.setIdentity();
117 
118  btScalar radius = getRadius();
119 
120  btVector3 halfExtents(radius, radius, radius);
121  halfExtents[getUpAxis()] += getHalfHeight();
122 
123  btScalar lx = btScalar(2.) * (halfExtents[0]);
124  btScalar ly = btScalar(2.) * (halfExtents[1]);
125  btScalar lz = btScalar(2.) * (halfExtents[2]);
126  const btScalar x2 = lx * lx;
127  const btScalar y2 = ly * ly;
128  const btScalar z2 = lz * lz;
129  const btScalar scaledmass = mass * btScalar(.08333333);
130 
131  inertia[0] = scaledmass * (y2 + z2);
132  inertia[1] = scaledmass * (x2 + z2);
133  inertia[2] = scaledmass * (x2 + y2);
134 }
135 
137 {
138  m_collisionMargin = radius;
139  m_upAxis = 0;
140  m_implicitShapeDimensions.setValue(0.5f * height, radius, radius);
141 }
142 
144 {
145  m_collisionMargin = radius;
146  m_upAxis = 2;
147  m_implicitShapeDimensions.setValue(radius, radius, 0.5f * height);
148 }
@ CAPSULE_SHAPE_PROXYTYPE
float btScalar
The btScalar type abstracts floating point numbers, to easily switch between double and single floati...
Definition: btScalar.h:314
#define BT_LARGE_FLOAT
Definition: btScalar.h:316
btScalar btSqrt(btScalar y)
Definition: btScalar.h:466
btCapsuleShapeX(btScalar radius, btScalar height)
btCapsuleShapeZ(btScalar radius, btScalar height)
btCapsuleShape()
only used for btCapsuleShapeZ and btCapsuleShapeX subclasses.
btScalar getRadius() const
virtual btVector3 localGetSupportingVertexWithoutMargin(const btVector3 &vec) const
btConvexShape Interface
virtual void calculateLocalInertia(btScalar mass, btVector3 &inertia) const
CollisionShape Interface.
int getUpAxis() const
btScalar getHalfHeight() const
virtual void batchedUnitVectorGetSupportingVertexWithoutMargin(const btVector3 *vectors, btVector3 *supportVerticesOut, int numVectors) const
The btConvexInternalShape is an internal base class, shared by most convex shape implementations.
The btTransform class supports rigid transforms with only translation and rotation and no scaling/she...
Definition: btTransform.h:30
void setIdentity()
Set this transformation to the identity.
Definition: btTransform.h:166
btVector3 can be used to represent 3D points and vectors.
Definition: btVector3.h:82
btScalar dot(const btVector3 &v) const
Return the dot product.
Definition: btVector3.h:229
void setValue(const btScalar &_x, const btScalar &_y, const btScalar &_z)
Definition: btVector3.h:640
btScalar length2() const
Return the length of the vector squared.
Definition: btVector3.h:251