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fixed the multibody jitter issue + several friction-related fixes

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This commit is contained in:
kubas
2014-01-09 01:12:02 +01:00
parent 736ba01423
commit cbf2d915d1
1 changed files with 38 additions and 23 deletions
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37
src/BulletDynamics/Featherstone/btMultiBodyConstraintSolver.cpp
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@@ -159,6 +159,8 @@ void btMultiBodyConstraintSolver::resolveSingleConstraintRowGeneric(const btMult
if (c.m_multiBodyA)
{
applyDeltaVee(&m_data.m_deltaVelocitiesUnitImpulse[c.m_jacAindex],deltaImpulse,c.m_deltaVelAindex,ndofA);
//note: update of the actual velocities (below) in the multibody does not have to happen now since m_deltaVelocities can be applied after all iterations
//it would make the multibody solver more like the regular one with m_deltaVelocities being equivalent to btSolverBody::m_deltaLinearVelocity/m_deltaAngularVelocity
if(c.m_multiBodyA->isMultiDof())
c.m_multiBodyA->applyDeltaVeeMultiDof(&m_data.m_deltaVelocitiesUnitImpulse[c.m_jacAindex],deltaImpulse);
else
@@ -171,6 +173,8 @@ void btMultiBodyConstraintSolver::resolveSingleConstraintRowGeneric(const btMult
if (c.m_multiBodyB)
{
applyDeltaVee(&m_data.m_deltaVelocitiesUnitImpulse[c.m_jacBindex],deltaImpulse,c.m_deltaVelBindex,ndofB);
//note: update of the actual velocities (below) in the multibody does not have to happen now since m_deltaVelocities can be applied after all iterations
//it would make the multibody solver more like the regular one with m_deltaVelocities being equivalent to btSolverBody::m_deltaLinearVelocity/m_deltaAngularVelocity
if(c.m_multiBodyB->isMultiDof())
c.m_multiBodyB->applyDeltaVeeMultiDof(&m_data.m_deltaVelocitiesUnitImpulse[c.m_jacBindex],deltaImpulse);
else
@@ -458,12 +462,14 @@ void btMultiBodyConstraintSolver::setupMultiBodyContactConstraint(btMultiBodySol
solverConstraint.m_friction = cp.m_combinedFriction;
if(!isFriction)
{
restitution = restitutionCurve(rel_vel, cp.m_combinedRestitution);
if (restitution <= btScalar(0.))
{
restitution = 0.f;
};
}
}
}
@@ -512,10 +518,8 @@ void btMultiBodyConstraintSolver::setupMultiBodyContactConstraint(btMultiBodySol
{
btScalar positionalError = 0.f;
btScalar velocityError = restitution - rel_vel;// * damping;
btScalar velocityError = restitution - rel_vel;// * damping; //note for friction restitution is always set to 0 (check above) so it is acutally velocityError = -rel_vel for friction
btScalar erp = infoGlobal.m_erp2;
if (!infoGlobal.m_splitImpulse || (penetration > infoGlobal.m_splitImpulsePenetrationThreshold))
@@ -526,7 +530,7 @@ void btMultiBodyConstraintSolver::setupMultiBodyContactConstraint(btMultiBodySol
if (penetration>0)
{
positionalError = 0;
velocityError = -penetration / infoGlobal.m_timeStep;
velocityError -= penetration / infoGlobal.m_timeStep;
} else
{
@@ -536,6 +540,8 @@ void btMultiBodyConstraintSolver::setupMultiBodyContactConstraint(btMultiBodySol
btScalar penetrationImpulse = positionalError*solverConstraint.m_jacDiagABInv;
btScalar velocityImpulse = velocityError *solverConstraint.m_jacDiagABInv;
if(!isFriction)
{
if (!infoGlobal.m_splitImpulse || (penetration > infoGlobal.m_splitImpulsePenetrationThreshold))
{
//combine position and velocity into rhs
@@ -549,10 +555,19 @@ void btMultiBodyConstraintSolver::setupMultiBodyContactConstraint(btMultiBodySol
solverConstraint.m_rhsPenetration = penetrationImpulse;
}
solverConstraint.m_cfm = 0.f;
solverConstraint.m_lowerLimit = 0;
solverConstraint.m_upperLimit = 1e10f;
}
else
{
solverConstraint.m_rhs = velocityImpulse;
solverConstraint.m_rhsPenetration = 0.f;
solverConstraint.m_lowerLimit = -solverConstraint.m_friction;
solverConstraint.m_upperLimit = solverConstraint.m_friction;
}
solverConstraint.m_cfm = 0.f; //why not use cfmSlip?
}
}
@@ -734,6 +749,10 @@ void btMultiBodyConstraintSolver::convertMultiBodyContact(btPersistentManifold*
{
btPlaneSpace1(cp.m_normalWorldOnB,cp.m_lateralFrictionDir1,cp.m_lateralFrictionDir2);
applyAnisotropicFriction(colObj0,cp.m_lateralFrictionDir1,btCollisionObject::CF_ANISOTROPIC_FRICTION);
applyAnisotropicFriction(colObj1,cp.m_lateralFrictionDir1,btCollisionObject::CF_ANISOTROPIC_FRICTION);
addMultiBodyFrictionConstraint(cp.m_lateralFrictionDir1,manifold,frictionIndex,cp,colObj0,colObj1, relaxation,infoGlobal);
if ((infoGlobal.m_solverMode & SOLVER_USE_2_FRICTION_DIRECTIONS))
{
applyAnisotropicFriction(colObj0,cp.m_lateralFrictionDir2,btCollisionObject::CF_ANISOTROPIC_FRICTION);
@@ -741,10 +760,6 @@ void btMultiBodyConstraintSolver::convertMultiBodyContact(btPersistentManifold*
addMultiBodyFrictionConstraint(cp.m_lateralFrictionDir2,manifold,frictionIndex,cp,colObj0,colObj1, relaxation,infoGlobal);
}
applyAnisotropicFriction(colObj0,cp.m_lateralFrictionDir1,btCollisionObject::CF_ANISOTROPIC_FRICTION);
applyAnisotropicFriction(colObj1,cp.m_lateralFrictionDir1,btCollisionObject::CF_ANISOTROPIC_FRICTION);
addMultiBodyFrictionConstraint(cp.m_lateralFrictionDir1,manifold,frictionIndex,cp,colObj0,colObj1, relaxation,infoGlobal);
if ((infoGlobal.m_solverMode & SOLVER_USE_2_FRICTION_DIRECTIONS) && (infoGlobal.m_solverMode & SOLVER_DISABLE_VELOCITY_DEPENDENT_FRICTION_DIRECTION))
{
cp.m_lateralFrictionInitialized = true;