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物体跟随鼠标旋转

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Mathf.Clamp(,)把数值限制在最大和最小之间，value小于min返回min，大于max，返回max

	    private float maxYRotation = 120;
	    private float minYRotation = 0;
	    private float maxXRotation = 60;
	    private float minXRotation = 0;
 		 float xPosPer = Input.mousePosition.x / Screen.width;`//鼠标在x方向于屏幕的比例`
        float yPosPer = Input.mousePosition.y / Screen.height;//鼠标在y方向于屏幕的比例
        float xAngle = -Mathf.Clamp(yPosPer*maxXRotation,minXRotation,maxYRotation)+15;
        float yAngle = Mathf.Clamp(xPosPer * maxYRotation, minXRotation, maxYRotation) - 60;
        transform.eulerAngles = new Vector3(xAngle,yAngle,0);