void TimeStepController::contactCallbackFunction(const unsigned int contactType, const unsigned int bodyIndex1, const unsigned int bodyIndex2,
		const Vector3r &cp1, const Vector3r &cp2, 
		const Vector3r &normal, const Real dist,
		const Real restitutionCoeff, const Real frictionCoeff, void *userData)
{
	SimulationModel *model = (SimulationModel*)userData;
	if (contactType == CollisionDetection::RigidBodyContactType)
		model->addRigidBodyContactConstraint(bodyIndex1, bodyIndex2, cp1, cp2, normal, dist, restitutionCoeff,frictionCoeff);
	else if (contactType == CollisionDetection::ParticleRigidBodyContactType)
		model->addParticleRigidBodyContactConstraint(bodyIndex1, bodyIndex2, cp1, cp2, normal, dist, restitutionCoeff, frictionCoeff);
}