Unity用鼠标滑轮控制摄像机缩放画面

using UnityEngine;
using System.Collections;

public class Scale : MonoBehaviour {
	public float ScaleSpeed = 10.0f;
	void Start () {
		
	}
	
	
	void Update () 
	{
		//Zoom out
		if (Input.GetAxis("Mouse ScrollWheel") <0)
		{
			Camera.main.transform.Translate(0,0,-1*ScaleSpeed);
		}
		//Zoom in
		if (Input.GetAxis("Mouse ScrollWheel") > 0)
		{
			Camera.main.transform.Translate(0,0,1*ScaleSpeed);
		}
	}
}