@Override
	public void update(GameContainer gc, int delta) {
		// TODO Auto-generated method stub
		Vector2 oldPos = position.copy();
		Vector2 steeringForce = behavior.calculate();
		Vector2 acceleration = steeringForce.divideBy(mass);
		velocity.add(acceleration.multiply(delta * MOVEMENT_PER_MS));
		velocity.truncate(maxSpeed);
		position.add(velocity.multiply(delta * MOVEMENT_PER_MS));
		this.heading = velocity.normalizeCopy();
		this.side = this.heading.perp();
		if(velocity.getX() > 0) {
			currentAnimation = birdRight;
		} else if(velocity.getX() < 0) { //do this so if velocity is 0, it stays at the last animation
			currentAnimation = birdLeft;
		}
	}