public SoccerBall(Vector2D pos, double ballSize, double mass, ArrayList<Wall2D> pitchBoundary) { // set up the base class super(); setPositionParams(pos); setDirectionParams(ballSize, new Vector2D(0d, 0d), new Vector2D(0d, 1d), new Vector2D(1d, 1d)); setEnergy( mass, -1.0, // max speed - unused 0, // turn rate - unused 0); // max force - unused this.pitchBoundary = pitchBoundary; oldPos = new Vector2D(0d, 0d); // oldPos = pos.cloneVec(); }