public RevoluteJoint(RevoluteJointDef def)
: base(def)
{
_localAnchor1 = def.LocalAnchor1;
_localAnchor2 = def.LocalAnchor2;
_referenceAngle = def.ReferenceAngle;
_impulse = new Vec3();
_motorImpulse = 0.0f;
_lowerAngle = def.LowerAngle;
_upperAngle = def.UpperAngle;
_maxMotorTorque = def.MaxMotorTorque;
_motorSpeed = def.MotorSpeed;
_enableLimit = def.EnableLimit;
_enableMotor = def.EnableMotor;
_limitState = LimitState.InactiveLimit;
}