src/BulletCollision/CollisionShapes/btCapsuleShape.cpp

   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
  19 #include "BulletCollision/CollisionShapes/btCollisionMargin.h"
  20 #include "LinearMath/btQuaternion.h"
  21
  22 btCapsuleShape::btCapsuleShape(btScalar radius, btScalar height) : btConvexInternalShape ()
  23 {
  24         m_shapeType = CAPSULE_SHAPE_PROXYTYPE;
  25         m_upAxis = 1;
  26         m_implicitShapeDimensions.setValue(radius,0.5f*height,radius);
  27 }
  28
  29
  30  btVector3      btCapsuleShape::localGetSupportingVertexWithoutMargin(const btVector3& vec0)const
  31 {
  32
  33         btVector3 supVec(0,0,0);
  34
  35         btScalar maxDot(btScalar(-BT_LARGE_FLOAT));
  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         {
  91                 btScalar maxDot(btScalar(-BT_LARGE_FLOAT));
  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
 123 void    btCapsuleShape::calculateLocalInertia(btScalar mass,btVector3& inertia) const
 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
 136         btScalar margin = CONVEX_DISTANCE_MARGIN;
 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
 152 btCapsuleShapeX::btCapsuleShapeX(btScalar radius,btScalar height)
 153 {
 154         m_upAxis = 0;
 155         m_implicitShapeDimensions.setValue(0.5f*height, radius,radius);
 156 }
 157
 158
 159
 160
 161
 162
 163 btCapsuleShapeZ::btCapsuleShapeZ(btScalar radius,btScalar height)
 164 {
 165         m_upAxis = 2;
 166         m_implicitShapeDimensions.setValue(radius,radius,0.5f*height);
 167 }
 168
 169
 170
 171