Unity相机的旋转缩放

摄像机的旋转，这里用的Rotate。
摄像机的缩放有两种方法，一种是filedOfView的改变，一种是改变摄像机Z轴的位置。都是可以的，下面是代码：

public float zoomSpeed = 10; //缩放速度
public float rotateSpeed = 1; //旋转速度
private float delta_z;
private float delta_rotation_x, delta_rotation_y;

void Update()
{
    //摄像机旋转
    if (Input.GetMouseButton(0))
    {
        delta_rotation_x = -Input.GetAxis("Mouse X") * rotateSpeed;
        delta_rotation_y = Input.GetAxis("Mouse Y") * rotateSpeed;

        transform.Rotate(0, delta_rotation_x, 0, Space.World);
        transform.Rotate(delta_rotation_y, 0, 0);
    }
    //摄像机缩放
    if (Input.GetAxis("Mouse ScrollWheel") != 0)
    {
        delta_z = -Input.GetAxis("Mouse ScrollWheel") * zoomSpeed;

//             //第一种方法，改变注摄像机的filedOfView
//             Camera.main.fieldOfView += delta_z;
//             if (Camera.main.fieldOfView < 10) Camera.main.fieldOfView = 10;
//             if (Camera.main.fieldOfView > 100) Camera.main.fieldOfView = 100;

        //第二种方法，改变摄像机的Z轴值
        transform.Translate(0, 0, -delta_z);
        if (transform.localPosition.z > -2)
        {
            transform.localPosition = new Vector3(transform.localPosition.x, transform.localPosition.y, -2);
        }
        if (transform.localPosition.z < -25)
        {
            transform.localPosition = new Vector3(transform.localPosition.x, transform.localPosition.y, -25);
        }
    }
}