public Transform target;//获取旋转目标

private void camerarotate() //摄像机围绕目标旋转操作
    {
        transform.RotateAround(target.position, Vector3.up, speed*Time.deltaTime); //摄像机围绕目标旋转
        var mouse_x = Input.GetAxis("Mouse X");//获取鼠标X轴移动
        var mouse_y = -Input.GetAxis("Mouse Y");//获取鼠标Y轴移动
        if (Input.GetKey(KeyCode.Mouse1))
        {
            transform.Translate(Vector3.left*(mouse_x*15f)*Time.deltaTime);
            transform.Translate(Vector3.up*(mouse_y*15f)*Time.deltaTime);
        }
        if (Input.GetKey(KeyCode.Mouse0))
        {
            transform.RotateAround(target.transform.position, Vector3.up, mouse_x*5);
            transform.RotateAround(target.transform.position, transform.right, mouse_y*5);
        }
    }

    private void camerazoom() //摄像机滚轮缩放
    {
        if (Input.GetAxis("Mouse ScrollWheel") > 0)
            transform.Translate(Vector3.forward*0.5f);


        if (Input.GetAxis("Mouse ScrollWheel") < 0)
            transform.Translate(Vector3.forward*-0.5f);
    }