public LineJoint(LineJointDef def)
: base(def)
{
_localAnchor1 = def.localAnchor1;
_localAnchor2 = def.localAnchor2;
_localXAxis1 = def.localAxis1;
_localYAxis1 = Vec2.Cross(1.0f, _localXAxis1);
_impulse.SetZero();
_motorMass = 0.0f;
_motorImpulse = 0.0f;
_lowerTranslation = def.lowerTranslation;
_upperTranslation = def.upperTranslation;
_maxMotorForce = Settings.FORCE_INV_SCALE(def.maxMotorForce);
_motorSpeed = def.motorSpeed;
_enableLimit = def.enableLimit;
_enableMotor = def.enableMotor;
_limitState = LimitState.InactiveLimit;
_axis.SetZero();
_perp.SetZero();
}