1、打开unity，新建一个工程，具体如下图
2、在场景中添加一个 Cube，效果如下图
3、在工程中，添加一个脚本 FollowMouseScale，双击打开脚本进行编辑，具体如下图
4、FollowMouseScale 脚本具体代码和代码说明如下图FollowMouseScale
5、FollowMouseScale 脚本具体内容如下：
using UnityEngine;
public class FollowMouseScale : MonoBehaviour {
public float scaleSpeed = 5.0f;
private float minScale = 1.0f;
private float maxScale = 150.0f;
private float currentScale;
// Use this for initialization
void Start () {
//根据当前摄像机是正交还是透视进行对应赋值
if (Camera.main.orthographic == true)
{
currentScale = Camera.main.orthographicSize;
}
else
{
currentScale = Camera.main.fieldOfView;
}
}
// Update is called once per frame
void Update () {
//获取鼠标滚轮的值，向前大于0，向后小于0，并设置放大缩小范围值
currentScale += Input.GetAxis("Mouse ScrollWheel") * scaleSpeed;
currentScale = Mathf.Clamp(currentScale, minScale, maxScale);
//根据当前摄像机是正交还是透视进行对应赋值，放大缩小
if (Camera.main.orthographic == true)
{
Camera.main.orthographicSize = currentScale;
}
else {
Camera.main.fieldOfView = currentScale;
}
}
}
6、脚本编译正确，回到Unity，在场景中添加一个 GameObject，把脚本挂载上去，具体如下图
7、运行场景，前后滚动滚轮，摄像头视野相应地放大缩小，具体如下图
