private void updateGravityAnimation() {
		gravityAngle = gravityAngle + gravityAngleSpeed;
		if (gravityAngle < 0 && gravityAngle < (0-tpi)) {
			gravityAngle += tpi;
		} else if (gravityAngle >= 0 && gravityAngle > tpi) {
			gravityAngle += (0-tpi);
		}
	}