src/BulletDynamics/ConstraintSolver/btPoint2PointConstraint.cpp

   1 /*
   2 Bullet Continuous Collision Detection and Physics Library
   3 Copyright (c) 2003-2006 Erwin Coumans  http://continuousphysics.com/Bullet/
   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 "btPoint2PointConstraint.h"
  18 #include "BulletDynamics/Dynamics/btRigidBody.h"
  19 #include <new>
  20
  21
  22
  23
  24
  25 btPoint2PointConstraint::btPoint2PointConstraint(btRigidBody& rbA,btRigidBody& rbB, const btVector3& pivotInA,const btVector3& pivotInB)
  26 :btTypedConstraint(POINT2POINT_CONSTRAINT_TYPE,rbA,rbB),m_pivotInA(pivotInA),m_pivotInB(pivotInB),
  27 m_flags(0),
  28 m_useSolveConstraintObsolete(false)
  29 {
  30
  31 }
  32
  33
  34 btPoint2PointConstraint::btPoint2PointConstraint(btRigidBody& rbA,const btVector3& pivotInA)
  35 :btTypedConstraint(POINT2POINT_CONSTRAINT_TYPE,rbA),m_pivotInA(pivotInA),m_pivotInB(rbA.getCenterOfMassTransform()(pivotInA)),
  36 m_flags(0),
  37 m_useSolveConstraintObsolete(false)
  38 {
  39
  40 }
  41
  42 void    btPoint2PointConstraint::buildJacobian()
  43 {
  44
  45         ///we need it for both methods
  46         {
  47                 m_appliedImpulse = btScalar(0.);
  48
  49                 btVector3       normal(0,0,0);
  50
  51                 for (int i=0;i<3;i++)
  52                 {
  53                         normal[i] = 1;
  54                         new (&m_jac[i]) btJacobianEntry(
  55                         m_rbA.getCenterOfMassTransform().getBasis().transpose(),
  56                         m_rbB.getCenterOfMassTransform().getBasis().transpose(),
  57                         m_rbA.getCenterOfMassTransform()*m_pivotInA - m_rbA.getCenterOfMassPosition(),
  58                         m_rbB.getCenterOfMassTransform()*m_pivotInB - m_rbB.getCenterOfMassPosition(),
  59                         normal,
  60                         m_rbA.getInvInertiaDiagLocal(),
  61                         m_rbA.getInvMass(),
  62                         m_rbB.getInvInertiaDiagLocal(),
  63                         m_rbB.getInvMass());
  64                 normal[i] = 0;
  65                 }
  66         }
  67
  68
  69 }
  70
  71 void btPoint2PointConstraint::getInfo1 (btConstraintInfo1* info)
  72 {
  73         getInfo1NonVirtual(info);
  74 }
  75
  76 void btPoint2PointConstraint::getInfo1NonVirtual (btConstraintInfo1* info)
  77 {
  78         if (m_useSolveConstraintObsolete)
  79         {
  80                 info->m_numConstraintRows = 0;
  81                 info->nub = 0;
  82         } else
  83         {
  84                 info->m_numConstraintRows = 3;
  85                 info->nub = 3;
  86         }
  87 }
  88
  89
  90
  91
  92 void btPoint2PointConstraint::getInfo2 (btConstraintInfo2* info)
  93 {
  94         getInfo2NonVirtual(info, m_rbA.getCenterOfMassTransform(),m_rbB.getCenterOfMassTransform());
  95 }
  96
  97 void btPoint2PointConstraint::getInfo2NonVirtual (btConstraintInfo2* info, const btTransform& body0_trans, const btTransform& body1_trans)
  98 {
  99         btAssert(!m_useSolveConstraintObsolete);
 100
 101          //retrieve matrices
 102
 103         // anchor points in global coordinates with respect to body PORs.
 104
 105     // set jacobian
 106     info->m_J1linearAxis[0] = 1;
 107         info->m_J1linearAxis[info->rowskip+1] = 1;
 108         info->m_J1linearAxis[2*info->rowskip+2] = 1;
 109
 110         btVector3 a1 = body0_trans.getBasis()*getPivotInA();
 111         {
 112                 btVector3* angular0 = (btVector3*)(info->m_J1angularAxis);
 113                 btVector3* angular1 = (btVector3*)(info->m_J1angularAxis+info->rowskip);
 114                 btVector3* angular2 = (btVector3*)(info->m_J1angularAxis+2*info->rowskip);
 115                 btVector3 a1neg = -a1;
 116                 a1neg.getSkewSymmetricMatrix(angular0,angular1,angular2);
 117         }
 118
 119         /*info->m_J2linearAxis[0] = -1;
 120     info->m_J2linearAxis[s+1] = -1;
 121     info->m_J2linearAxis[2*s+2] = -1;
 122         */
 123
 124         btVector3 a2 = body1_trans.getBasis()*getPivotInB();
 125
 126         {
 127         //      btVector3 a2n = -a2;
 128                 btVector3* angular0 = (btVector3*)(info->m_J2angularAxis);
 129                 btVector3* angular1 = (btVector3*)(info->m_J2angularAxis+info->rowskip);
 130                 btVector3* angular2 = (btVector3*)(info->m_J2angularAxis+2*info->rowskip);
 131                 a2.getSkewSymmetricMatrix(angular0,angular1,angular2);
 132         }
 133
 134
 135
 136     // set right hand side
 137         btScalar currERP = (m_flags & BT_P2P_FLAGS_ERP) ? m_erp : info->erp;
 138     btScalar k = info->fps * currERP;
 139     int j;
 140         for (j=0; j<3; j++)
 141     {
 142         info->m_constraintError[j*info->rowskip] = k * (a2[j] + body1_trans.getOrigin()[j] - a1[j] - body0_trans.getOrigin()[j]);
 143                 //printf("info->m_constraintError[%d]=%f\n",j,info->m_constraintError[j]);
 144     }
 145         if(m_flags & BT_P2P_FLAGS_CFM)
 146         {
 147                 for (j=0; j<3; j++)
 148                 {
 149                         info->cfm[j*info->rowskip] = m_cfm;
 150                 }
 151         }
 152
 153         btScalar impulseClamp = m_setting.m_impulseClamp;//
 154         for (j=0; j<3; j++)
 155     {
 156                 if (m_setting.m_impulseClamp > 0)
 157                 {
 158                         info->m_lowerLimit[j*info->rowskip] = -impulseClamp;
 159                         info->m_upperLimit[j*info->rowskip] = impulseClamp;
 160                 }
 161         }
 162         info->m_damping = m_setting.m_damping;
 163
 164 }
 165
 166
 167
 168 void    btPoint2PointConstraint::updateRHS(btScalar     timeStep)
 169 {
 170         (void)timeStep;
 171
 172 }
 173
 174 ///override the default global value of a parameter (such as ERP or CFM), optionally provide the axis (0..5).
 175 ///If no axis is provided, it uses the default axis for this constraint.
 176 void btPoint2PointConstraint::setParam(int num, btScalar value, int axis)
 177 {
 178         if(axis != -1)
 179         {
 180                 btAssertConstrParams(0);
 181         }
 182         else
 183         {
 184                 switch(num)
 185                 {
 186                         case BT_CONSTRAINT_ERP :
 187                         case BT_CONSTRAINT_STOP_ERP :
 188                                 m_erp = value;
 189                                 m_flags |= BT_P2P_FLAGS_ERP;
 190                                 break;
 191                         case BT_CONSTRAINT_CFM :
 192                         case BT_CONSTRAINT_STOP_CFM :
 193                                 m_cfm = value;
 194                                 m_flags |= BT_P2P_FLAGS_CFM;
 195                                 break;
 196                         default:
 197                                 btAssertConstrParams(0);
 198                 }
 199         }
 200 }
 201
 202 ///return the local value of parameter
 203 btScalar btPoint2PointConstraint::getParam(int num, int axis) const
 204 {
 205         btScalar retVal(SIMD_INFINITY);
 206         if(axis != -1)
 207         {
 208                 btAssertConstrParams(0);
 209         }
 210         else
 211         {
 212                 switch(num)
 213                 {
 214                         case BT_CONSTRAINT_ERP :
 215                         case BT_CONSTRAINT_STOP_ERP :
 216                                 btAssertConstrParams(m_flags & BT_P2P_FLAGS_ERP);
 217                                 retVal = m_erp;
 218                                 break;
 219                         case BT_CONSTRAINT_CFM :
 220                         case BT_CONSTRAINT_STOP_CFM :
 221                                 btAssertConstrParams(m_flags & BT_P2P_FLAGS_CFM);
 222                                 retVal = m_cfm;
 223                                 break;
 224                         default:
 225                                 btAssertConstrParams(0);
 226                 }
 227         }
 228         return retVal;
 229 }
 230