Bullet Collision Detection & Physics Library
btMinkowskiSumShape.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 "btMinkowskiSumShape.h"
18 
19 
22 m_shapeA(shapeA),
23 m_shapeB(shapeB)
24 {
28 }
29 
31 {
34  return supVertexA - supVertexB;
35 }
36 
37 void btMinkowskiSumShape::batchedUnitVectorGetSupportingVertexWithoutMargin(const btVector3* vectors,btVector3* supportVerticesOut,int numVectors) const
38 {
40  for (int i=0;i<numVectors;i++)
41  {
42  supportVerticesOut[i] = localGetSupportingVertexWithoutMargin(vectors[i]);
43  }
44 
45 }
46 
47 
48 
50 {
51  return m_shapeA->getMargin() + m_shapeB->getMargin();
52 }
53 
54 
56 {
57  (void)mass;
58  //inertia of the AABB of the Minkowski sum
59  btTransform identity;
60  identity.setIdentity();
61  btVector3 aabbMin,aabbMax;
62  getAabb(identity,aabbMin,aabbMax);
63 
64  btVector3 halfExtents = (aabbMax-aabbMin)*btScalar(0.5);
65 
66  btScalar margin = getMargin();
67 
68  btScalar lx=btScalar(2.)*(halfExtents.x()+margin);
69  btScalar ly=btScalar(2.)*(halfExtents.y()+margin);
70  btScalar lz=btScalar(2.)*(halfExtents.z()+margin);
71  const btScalar x2 = lx*lx;
72  const btScalar y2 = ly*ly;
73  const btScalar z2 = lz*lz;
74  const btScalar scaledmass = mass * btScalar(0.08333333);
75 
76  inertia = scaledmass * (btVector3(y2+z2,x2+z2,x2+y2));
77 }
const btConvexShape * m_shapeB
virtual void batchedUnitVectorGetSupportingVertexWithoutMargin(const btVector3 *vectors, btVector3 *supportVerticesOut, int numVectors) const
btMinkowskiSumShape(const btConvexShape *shapeA, const btConvexShape *shapeB)
void getAabb(const btTransform &t, btVector3 &aabbMin, btVector3 &aabbMax) const
getAabb&#39;s default implementation is brute force, expected derived classes to implement a fast dedicat...
virtual btVector3 localGetSupportingVertexWithoutMargin(const btVector3 &vec) const
The btConvexInternalShape is an internal base class, shared by most convex shape implementations.
void setIdentity()
Set this transformation to the identity.
Definition: btTransform.h:172
virtual btVector3 localGetSupportingVertexWithoutMargin(const btVector3 &vec) const =0
virtual btScalar getMargin() const
virtual void calculateLocalInertia(btScalar mass, btVector3 &inertia) const
const btScalar & x() const
Return the x value.
Definition: btVector3.h:587
The btConvexShape is an abstract shape interface, implemented by all convex shapes such as btBoxShape...
Definition: btConvexShape.h:31
const btConvexShape * m_shapeA
btMatrix3x3 & getBasis()
Return the basis matrix for the rotation.
Definition: btTransform.h:112
virtual btScalar getMargin() const =0
const btScalar & y() const
Return the y value.
Definition: btVector3.h:589
btVector3 can be used to represent 3D points and vectors.
Definition: btVector3.h:83
The btTransform class supports rigid transforms with only translation and rotation and no scaling/she...
Definition: btTransform.h:34
float btScalar
The btScalar type abstracts floating point numbers, to easily switch between double and single floati...
Definition: btScalar.h:292
const btScalar & z() const
Return the z value.
Definition: btVector3.h:591