Bullet Collision Detection & Physics Library: btCapsuleShape.cpp Source File

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btCapsuleShape.cpp
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1/*
2Bullet Continuous Collision Detection and Physics Library
3Copyright (c) 2003-2009 Erwin Coumans http://bulletphysics.org
4
5This software is provided 'as-is', without any express or implied warranty.
6In no event will the authors be held liable for any damages arising from the use of this software.
7Permission is granted to anyone to use this software for any purpose,
8including commercial applications, and to alter it and redistribute it freely,
9subject to the following restrictions:
10
111. 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.
122. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
133. This notice may not be removed or altered from any source distribution.
14*/
15
16#include "btCapsuleShape.h"
17
18#include "LinearMath/btQuaternion.h"
19
20 btCapsuleShape::btCapsuleShape(btScalar radius, btScalar height) : btConvexInternalShape()
21{
22 m_collisionMargin = radius;
23 m_shapeType = CAPSULE_SHAPE_PROXYTYPE;
24 m_upAxis = 1;
25 m_implicitShapeDimensions.setValue(radius, 0.5f * height, radius);
26}
27
28 btVector3 btCapsuleShape::localGetSupportingVertexWithoutMargin(const btVector3& vec0) const
29{
30 btVector3 supVec(0, 0, 0);
31
32 btScalar maxDot(btScalar(-BT_LARGE_FLOAT));
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 {
81 btScalar maxDot(btScalar(-BT_LARGE_FLOAT));
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
111 void btCapsuleShape::calculateLocalInertia(btScalar mass, btVector3& inertia) const
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
136btCapsuleShapeX::btCapsuleShapeX(btScalar radius, btScalar height)
137{
138 m_collisionMargin = radius;
139 m_upAxis = 0;
140 m_implicitShapeDimensions.setValue(0.5f * height, radius, radius);
141}
142
143btCapsuleShapeZ::btCapsuleShapeZ(btScalar radius, btScalar height)
144{
145 m_collisionMargin = radius;
146 m_upAxis = 2;
147 m_implicitShapeDimensions.setValue(radius, radius, 0.5f * height);
148}
CAPSULE_SHAPE_PROXYTYPE
@ CAPSULE_SHAPE_PROXYTYPE
Definition btBroadphaseProxy.h:41
btCapsuleShape.h
btQuaternion.h
btScalar
float btScalar
The btScalar type abstracts floating point numbers, to easily switch between double and single floati...
Definition btScalar.h:314
BT_LARGE_FLOAT
#define BT_LARGE_FLOAT
Definition btScalar.h:316
btSqrt
btScalar btSqrt(btScalar y)
Definition btScalar.h:466
btCapsuleShapeX::btCapsuleShapeX
btCapsuleShapeX(btScalar radius, btScalar height)
Definition btCapsuleShape.cpp:136
btCapsuleShapeZ::btCapsuleShapeZ
btCapsuleShapeZ(btScalar radius, btScalar height)
Definition btCapsuleShape.cpp:143
btCapsuleShape::btCapsuleShape
btCapsuleShape()
only used for btCapsuleShapeZ and btCapsuleShapeX subclasses.
Definition btCapsuleShape.h:33
btCapsuleShape::getRadius
btScalar getRadius() const
Definition btCapsuleShape.h:76
btCapsuleShape::localGetSupportingVertexWithoutMargin
virtual btVector3 localGetSupportingVertexWithoutMargin(const btVector3 &vec) const
btConvexShape Interface
Definition btCapsuleShape.cpp:28
btCapsuleShape::calculateLocalInertia
virtual void calculateLocalInertia(btScalar mass, btVector3 &inertia) const
CollisionShape Interface.
Definition btCapsuleShape.cpp:111
btCapsuleShape::m_upAxis
int m_upAxis
Definition btCapsuleShape.h:29
btCapsuleShape::getUpAxis
int getUpAxis() const
Definition btCapsuleShape.h:71
btCapsuleShape::getHalfHeight
btScalar getHalfHeight() const
Definition btCapsuleShape.h:82
btCapsuleShape::batchedUnitVectorGetSupportingVertexWithoutMargin
virtual void batchedUnitVectorGetSupportingVertexWithoutMargin(const btVector3 *vectors, btVector3 *supportVerticesOut, int numVectors) const
Definition btCapsuleShape.cpp:77
btCollisionShape::m_shapeType
int m_shapeType
Definition btCollisionShape.h:30
btConvexInternalShape
The btConvexInternalShape is an internal base class, shared by most convex shape implementations.
Definition btConvexInternalShape.h:30
btConvexInternalShape::m_collisionMargin
btScalar m_collisionMargin
Definition btConvexInternalShape.h:37
btConvexInternalShape::m_implicitShapeDimensions
btVector3 m_implicitShapeDimensions
Definition btConvexInternalShape.h:35
btTransform
The btTransform class supports rigid transforms with only translation and rotation and no scaling/she...
Definition btTransform.h:30
btTransform::setIdentity
void setIdentity()
Set this transformation to the identity.
Definition btTransform.h:167
btVector3
btVector3 can be used to represent 3D points and vectors.
Definition btVector3.h:82
btVector3::dot
btScalar dot(const btVector3 &v) const
Return the dot product.
Definition btVector3.h:229
btVector3::setValue
void setValue(const btScalar &_x, const btScalar &_y, const btScalar &_z)
Definition btVector3.h:640
btVector3::length2
btScalar length2() const
Return the length of the vector squared.
Definition btVector3.h:251