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
btMultiBodyJointMotor(btMultiBody * body,int link,btScalar desiredVelocity,btScalar maxMotorImpulse)24 btMultiBodyJointMotor::btMultiBodyJointMotor(btMultiBody* body, int link, btScalar desiredVelocity, btScalar maxMotorImpulse)
25 :btMultiBodyConstraint(body,body,link,link,1,true),
26 m_desiredVelocity(desiredVelocity)
27 {
28 int linkDoF = 0;
29
30 m_maxAppliedImpulse = maxMotorImpulse;
31 // the data.m_jacobians never change, so may as well
32 // initialize them here
33
34 // note: we rely on the fact that data.m_jacobians are
35 // always initialized to zero by the Constraint ctor
36
37 unsigned int offset = 6 + (body->isMultiDof() ? body->getLink(link).m_dofOffset + linkDoF : link);
38
39 // row 0: the lower bound
40 // row 0: the lower bound
41 jacobianA(0)[offset] = 1;
42 }
43
44
btMultiBodyJointMotor(btMultiBody * body,int link,int linkDoF,btScalar desiredVelocity,btScalar maxMotorImpulse)45 btMultiBodyJointMotor::btMultiBodyJointMotor(btMultiBody* body, int link, int linkDoF, btScalar desiredVelocity, btScalar maxMotorImpulse)
46 //:btMultiBodyConstraint(body,0,link,-1,1,true),
47 :btMultiBodyConstraint(body,body,link,link,1,true),
48 m_desiredVelocity(desiredVelocity)
49 {
50 btAssert(linkDoF < body->getLink(link).m_dofCount);
51
52 m_maxAppliedImpulse = maxMotorImpulse;
53 // the data.m_jacobians never change, so may as well
54 // initialize them here
55
56 // note: we rely on the fact that data.m_jacobians are
57 // always initialized to zero by the Constraint ctor
58
59 unsigned int offset = 6 + (body->isMultiDof() ? body->getLink(link).m_dofOffset + linkDoF : link);
60
61 // row 0: the lower bound
62 // row 0: the lower bound
63 jacobianA(0)[offset] = 1;
64 }
~btMultiBodyJointMotor()65 btMultiBodyJointMotor::~btMultiBodyJointMotor()
66 {
67 }
68
getIslandIdA() const69 int btMultiBodyJointMotor::getIslandIdA() const
70 {
71 btMultiBodyLinkCollider* col = m_bodyA->getBaseCollider();
72 if (col)
73 return col->getIslandTag();
74 for (int i=0;i<m_bodyA->getNumLinks();i++)
75 {
76 if (m_bodyA->getLink(i).m_collider)
77 return m_bodyA->getLink(i).m_collider->getIslandTag();
78 }
79 return -1;
80 }
81
getIslandIdB() const82 int btMultiBodyJointMotor::getIslandIdB() const
83 {
84 btMultiBodyLinkCollider* col = m_bodyB->getBaseCollider();
85 if (col)
86 return col->getIslandTag();
87
88 for (int i=0;i<m_bodyB->getNumLinks();i++)
89 {
90 col = m_bodyB->getLink(i).m_collider;
91 if (col)
92 return col->getIslandTag();
93 }
94 return -1;
95 }
96
97
createConstraintRows(btMultiBodyConstraintArray & constraintRows,btMultiBodyJacobianData & data,const btContactSolverInfo & infoGlobal)98 void btMultiBodyJointMotor::createConstraintRows(btMultiBodyConstraintArray& constraintRows,
99 btMultiBodyJacobianData& data,
100 const btContactSolverInfo& infoGlobal)
101 {
102 // only positions need to be updated -- data.m_jacobians and force
103 // directions were set in the ctor and never change.
104
105
106 const btScalar posError = 0;
107 const btVector3 dummy(0, 0, 0);
108
109 for (int row=0;row<getNumRows();row++)
110 {
111 btMultiBodySolverConstraint& constraintRow = constraintRows.expandNonInitializing();
112
113
114 fillMultiBodyConstraint(constraintRow,data,jacobianA(row),jacobianB(row),dummy,dummy,dummy,posError,infoGlobal,-m_maxAppliedImpulse,m_maxAppliedImpulse,1,false,m_desiredVelocity);
115 }
116
117 }
118
119