1 /* 2 Bullet Continuous Collision Detection and Physics Library 3 Copyright (c) 2013 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 ///This file was written by Erwin Coumans 17 18 #include "btMultiBodyJointMotor.h" 19 #include "btMultiBody.h" 20 #include "btMultiBodyLinkCollider.h" 21 #include "BulletCollision/CollisionDispatch/btCollisionObject.h" 22 23 24 btMultiBodyJointMotor::btMultiBodyJointMotor(btMultiBody* body, int link, btScalar desiredVelocity, btScalar maxMotorImpulse) 25 :btMultiBodyConstraint(body,body,link,body->getLink(link).m_parent,1,true), 26 m_desiredVelocity(desiredVelocity) 27 { 28 29 m_maxAppliedImpulse = maxMotorImpulse; 30 // the data.m_jacobians never change, so may as well 31 // initialize them here 32 33 34 } 35 36 void btMultiBodyJointMotor::finalizeMultiDof() 37 { 38 allocateJacobiansMultiDof(); 39 // note: we rely on the fact that data.m_jacobians are 40 // always initialized to zero by the Constraint ctor 41 int linkDoF = 0; 42 unsigned int offset = 6 + (m_bodyA->isMultiDof() ? m_bodyA->getLink(m_linkA).m_dofOffset + linkDoF : m_linkA); 43 44 // row 0: the lower bound 45 // row 0: the lower bound 46 jacobianA(0)[offset] = 1; 47 48 m_numDofsFinalized = m_jacSizeBoth; 49 } 50 51 btMultiBodyJointMotor::btMultiBodyJointMotor(btMultiBody* body, int link, int linkDoF, btScalar desiredVelocity, btScalar maxMotorImpulse) 52 //:btMultiBodyConstraint(body,0,link,-1,1,true), 53 :btMultiBodyConstraint(body,body,link,body->getLink(link).m_parent,1,true), 54 m_desiredVelocity(desiredVelocity) 55 { 56 btAssert(linkDoF < body->getLink(link).m_dofCount); 57 58 m_maxAppliedImpulse = maxMotorImpulse; 59 60 } 61 btMultiBodyJointMotor::~btMultiBodyJointMotor() 62 { 63 } 64 65 int btMultiBodyJointMotor::getIslandIdA() const 66 { 67 btMultiBodyLinkCollider* col = m_bodyA->getBaseCollider(); 68 if (col) 69 return col->getIslandTag(); 70 for (int i=0;i<m_bodyA->getNumLinks();i++) 71 { 72 if (m_bodyA->getLink(i).m_collider) 73 return m_bodyA->getLink(i).m_collider->getIslandTag(); 74 } 75 return -1; 76 } 77 78 int btMultiBodyJointMotor::getIslandIdB() const 79 { 80 btMultiBodyLinkCollider* col = m_bodyB->getBaseCollider(); 81 if (col) 82 return col->getIslandTag(); 83 84 for (int i=0;i<m_bodyB->getNumLinks();i++) 85 { 86 col = m_bodyB->getLink(i).m_collider; 87 if (col) 88 return col->getIslandTag(); 89 } 90 return -1; 91 } 92 93 94 void btMultiBodyJointMotor::createConstraintRows(btMultiBodyConstraintArray& constraintRows, 95 btMultiBodyJacobianData& data, 96 const btContactSolverInfo& infoGlobal) 97 { 98 // only positions need to be updated -- data.m_jacobians and force 99 // directions were set in the ctor and never change. 100 101 if (m_numDofsFinalized != m_jacSizeBoth) 102 { 103 finalizeMultiDof(); 104 } 105 106 //don't crash 107 if (m_numDofsFinalized != m_jacSizeBoth) 108 return; 109 110 const btScalar posError = 0; 111 const btVector3 dummy(0, 0, 0); 112 113 for (int row=0;row<getNumRows();row++) 114 { 115 btMultiBodySolverConstraint& constraintRow = constraintRows.expandNonInitializing(); 116 117 118 fillMultiBodyConstraint(constraintRow,data,jacobianA(row),jacobianB(row),dummy,dummy,dummy,posError,infoGlobal,-m_maxAppliedImpulse,m_maxAppliedImpulse,1,false,m_desiredVelocity); 119 constraintRow.m_orgConstraint = this; 120 constraintRow.m_orgDofIndex = row; 121 if (m_bodyA->isMultiDof()) 122 { 123 //expect either prismatic or revolute joint type for now 124 btAssert((m_bodyA->getLink(m_linkA).m_jointType == btMultibodyLink::eRevolute)||(m_bodyA->getLink(m_linkA).m_jointType == btMultibodyLink::ePrismatic)); 125 switch (m_bodyA->getLink(m_linkA).m_jointType) 126 { 127 case btMultibodyLink::eRevolute: 128 { 129 constraintRow.m_contactNormal1.setZero(); 130 constraintRow.m_contactNormal2.setZero(); 131 btVector3 revoluteAxisInWorld = quatRotate(m_bodyA->getLink(m_linkA).m_cachedWorldTransform.getRotation(),m_bodyA->getLink(m_linkA).m_axes[0].m_topVec); 132 constraintRow.m_relpos1CrossNormal=revoluteAxisInWorld; 133 constraintRow.m_relpos2CrossNormal=-revoluteAxisInWorld; 134 135 break; 136 } 137 case btMultibodyLink::ePrismatic: 138 { 139 btVector3 prismaticAxisInWorld = quatRotate(m_bodyA->getLink(m_linkA).m_cachedWorldTransform.getRotation(),m_bodyA->getLink(m_linkA).m_axes[0].m_bottomVec); 140 constraintRow.m_contactNormal1=prismaticAxisInWorld; 141 constraintRow.m_contactNormal2=-prismaticAxisInWorld; 142 constraintRow.m_relpos1CrossNormal.setZero(); 143 constraintRow.m_relpos2CrossNormal.setZero(); 144 145 break; 146 } 147 default: 148 { 149 btAssert(0); 150 } 151 }; 152 153 } 154 155 } 156 157 } 158 159
