Files
bullet3/src/BulletDynamics/Featherstone/btMultiBodyJointLimitConstraint.cpp

298 lines
8.6 KiB
C++

#include "btMultiBodyJointLimitConstraint.h"
#include "btMultiBody.h"
#include "btMultiBodyLinkCollider.h"
#include "BulletCollision/CollisionDispatch/btCollisionObject.h"
btMultiBodyJointLimitConstraint::btMultiBodyJointLimitConstraint(btMultiBody* body, int link, btScalar lower, btScalar upper)
:btMultiBodyConstraint(body,body,link,link,2,true),
m_lowerBound(lower),
m_upperBound(upper)
{
// the data.m_jacobians never change, so may as well
// initialize them here
// note: we rely on the fact that data.m_jacobians are
// always initialized to zero by the Constraint ctor
// row 0: the lower bound
jacobianA(0)[6 + link] = 1;
// row 1: the upper bound
jacobianB(1)[6 + link] = -1;
}
btMultiBodyJointLimitConstraint::~btMultiBodyJointLimitConstraint()
{
}
int btMultiBodyJointLimitConstraint::getIslandIdA() const
{
return m_bodyA->getLinkCollider(0)->getIslandTag();
}
int btMultiBodyJointLimitConstraint::getIslandIdB() const
{
return m_bodyB->getLinkCollider(0)->getIslandTag();
}
void btMultiBodyJointLimitConstraint::createConstraintRows(btMultiBodyConstraintArray& constraintRows,
btMultiBodyJacobianData& data,
const btContactSolverInfo& infoGlobal)
{
// only positions need to be updated -- data.m_jacobians and force
// directions were set in the ctor and never change.
// row 0: the lower bound
setPosition(0, m_bodyA->getJointPos(m_linkA) - m_lowerBound);
// row 1: the upper bound
setPosition(1, m_upperBound - m_bodyA->getJointPos(m_linkA));
for (int row=0;row<getNumRows();row++)
{
btMultiBodySolverConstraint& constraintRow = constraintRows.expandNonInitializing();
constraintRow.m_multiBodyA = m_bodyA;
constraintRow.m_multiBodyB = m_bodyB;
btScalar penetration = getPosition(row);
fillConstraintRow(constraintRow,data,jacobianA(row),jacobianB(row),penetration,0,0,infoGlobal);
}
}
void btMultiBodyJointLimitConstraint::fillConstraintRow(btMultiBodySolverConstraint& constraintRow,
btMultiBodyJacobianData& data,
btScalar* jacOrgA,btScalar* jacOrgB,
btScalar penetration,btScalar combinedFrictionCoeff, btScalar combinedRestitutionCoeff,
const btContactSolverInfo& infoGlobal)
{
btMultiBody* multiBodyA = constraintRow.m_multiBodyA;
btMultiBody* multiBodyB = constraintRow.m_multiBodyB;
if (multiBodyA)
{
const int ndofA = multiBodyA->getNumLinks() + 6;
constraintRow.m_deltaVelAindex = multiBodyA->getCompanionId();
if (constraintRow.m_deltaVelAindex <0)
{
constraintRow.m_deltaVelAindex = data.m_deltaVelocities.size();
multiBodyA->setCompanionId(constraintRow.m_deltaVelAindex);
data.m_deltaVelocities.resize(data.m_deltaVelocities.size()+ndofA);
} else
{
btAssert(data.m_deltaVelocities.size() >= constraintRow.m_deltaVelAindex+ndofA);
}
constraintRow.m_jacAindex = data.m_jacobians.size();
data.m_jacobians.resize(data.m_jacobians.size()+ndofA);
data.m_deltaVelocitiesUnitImpulse.resize(data.m_deltaVelocitiesUnitImpulse.size()+ndofA);
btAssert(data.m_jacobians.size() == data.m_deltaVelocitiesUnitImpulse.size());
for (int i=0;i<ndofA;i++)
data.m_jacobians[constraintRow.m_jacAindex+i] = jacOrgA[i];
float* delta = &data.m_deltaVelocitiesUnitImpulse[constraintRow.m_jacAindex];
multiBodyA->calcAccelerationDeltas(&data.m_jacobians[constraintRow.m_jacAindex],delta,data.scratch_r, data.scratch_v);
}
if (multiBodyB)
{
const int ndofB = multiBodyB->getNumLinks() + 6;
constraintRow.m_deltaVelBindex = multiBodyB->getCompanionId();
if (constraintRow.m_deltaVelBindex <0)
{
constraintRow.m_deltaVelBindex = data.m_deltaVelocities.size();
multiBodyB->setCompanionId(constraintRow.m_deltaVelBindex);
data.m_deltaVelocities.resize(data.m_deltaVelocities.size()+ndofB);
}
constraintRow.m_jacBindex = data.m_jacobians.size();
data.m_jacobians.resize(data.m_jacobians.size()+ndofB);
for (int i=0;i<ndofB;i++)
data.m_jacobians[constraintRow.m_jacBindex+i] = jacOrgB[i];
data.m_deltaVelocitiesUnitImpulse.resize(data.m_deltaVelocitiesUnitImpulse.size()+ndofB);
btAssert(data.m_jacobians.size() == data.m_deltaVelocitiesUnitImpulse.size());
multiBodyB->calcAccelerationDeltas(&data.m_jacobians[constraintRow.m_jacBindex],&data.m_deltaVelocitiesUnitImpulse[constraintRow.m_jacBindex],data.scratch_r, data.scratch_v);
}
{
btVector3 vec;
btScalar denom0 = 0.f;
btScalar denom1 = 0.f;
btScalar* jacB = 0;
btScalar* jacA = 0;
btScalar* lambdaA =0;
btScalar* lambdaB =0;
int ndofA = 0;
if (multiBodyA)
{
ndofA = multiBodyA->getNumLinks() + 6;
jacA = &data.m_jacobians[constraintRow.m_jacAindex];
lambdaA = &data.m_deltaVelocitiesUnitImpulse[constraintRow.m_jacAindex];
for (int i = 0; i < ndofA; ++i)
{
float j = jacA[i] ;
float l =lambdaA[i];
denom0 += j*l;
}
}
if (multiBodyB)
{
const int ndofB = multiBodyB->getNumLinks() + 6;
jacB = &data.m_jacobians[constraintRow.m_jacBindex];
lambdaB = &data.m_deltaVelocitiesUnitImpulse[constraintRow.m_jacBindex];
for (int i = 0; i < ndofB; ++i)
{
float j = jacB[i] ;
float l =lambdaB[i];
denom1 += j*l;
}
}
if (multiBodyA && (multiBodyA==multiBodyB))
{
// ndof1 == ndof2 in this case
for (int i = 0; i < ndofA; ++i)
{
denom1 += jacB[i] * lambdaA[i];
denom1 += jacA[i] * lambdaB[i];
}
}
float d = denom0+denom1;
if (btFabs(d)>SIMD_EPSILON)
{
constraintRow.m_jacDiagABInv = 1.f/(d);
} else
{
constraintRow.m_jacDiagABInv = 1.f;
}
}
//compute rhs and remaining constraintRow fields
btScalar rel_vel = 0.f;
int ndofA = 0;
int ndofB = 0;
{
btVector3 vel1,vel2;
if (multiBodyA)
{
ndofA = multiBodyA->getNumLinks() + 6;
btScalar* jacA = &data.m_jacobians[constraintRow.m_jacAindex];
for (int i = 0; i < ndofA ; ++i)
rel_vel += multiBodyA->getVelocityVector()[i] * jacA[i];
}
if (multiBodyB)
{
ndofB = multiBodyB->getNumLinks() + 6;
btScalar* jacB = &data.m_jacobians[constraintRow.m_jacBindex];
for (int i = 0; i < ndofB ; ++i)
rel_vel += multiBodyB->getVelocityVector()[i] * jacB[i];
}
constraintRow.m_friction = combinedFrictionCoeff;
}
/*
///warm starting (or zero if disabled)
if (infoGlobal.m_solverMode & SOLVER_USE_WARMSTARTING)
{
constraintRow.m_appliedImpulse = isFriction ? 0 : cp.m_appliedImpulse * infoGlobal.m_warmstartingFactor;
if (constraintRow.m_appliedImpulse)
{
if (multiBodyA)
{
btScalar impulse = constraintRow.m_appliedImpulse;
btScalar* deltaV = &data.m_deltaVelocitiesUnitImpulse[constraintRow.m_jacAindex];
multiBodyA->applyDeltaVee(deltaV,impulse);
applyDeltaVee(deltaV,impulse,constraintRow.m_deltaVelAindex,ndofA);
}
if (multiBodyB)
{
btScalar impulse = constraintRow.m_appliedImpulse;
btScalar* deltaV = &data.m_deltaVelocitiesUnitImpulse[constraintRow.m_jacBindex];
multiBodyB->applyDeltaVee(deltaV,impulse);
applyDeltaVee(deltaV,impulse,constraintRow.m_deltaVelBindex,ndofB);
}
}
}
else
*/
{
constraintRow.m_appliedImpulse = 0.f;
}
constraintRow.m_appliedPushImpulse = 0.f;
{
float desiredVelocity = -0.3;
btScalar positionalError = 0.f;
btScalar velocityError = - rel_vel;// * damping;
btScalar erp = infoGlobal.m_erp2;
if (!infoGlobal.m_splitImpulse || (penetration > infoGlobal.m_splitImpulsePenetrationThreshold))
{
erp = infoGlobal.m_erp;
}
if (penetration>0)
{
positionalError = 0;
velocityError = -penetration / infoGlobal.m_timeStep;
} else
{
positionalError = -penetration * erp/infoGlobal.m_timeStep;
}
btScalar penetrationImpulse = positionalError*constraintRow.m_jacDiagABInv;
btScalar velocityImpulse = velocityError *constraintRow.m_jacDiagABInv;
if (!infoGlobal.m_splitImpulse || (penetration > infoGlobal.m_splitImpulsePenetrationThreshold))
{
//combine position and velocity into rhs
constraintRow.m_rhs = penetrationImpulse+velocityImpulse;
constraintRow.m_rhsPenetration = 0.f;
} else
{
//split position and velocity into rhs and m_rhsPenetration
constraintRow.m_rhs = velocityImpulse;
constraintRow.m_rhsPenetration = penetrationImpulse;
}
constraintRow.m_cfm = 0.f;
constraintRow.m_lowerLimit = 0;
constraintRow.m_upperLimit = 1e10f;
}
}