Unity 相机平移、旋转、缩放

内容不多，一个脚本，直接上代码

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;

 public class Move : MonoBehaviour
 {

     float speed = ;
     public float distance_v;
     public float distance_h;
     public float rotation_H_speed = ;
     public float rotation_V_speed = ;
     public float max_up_angle = ;              //越大，头抬得越高
     public float max_down_angle = -;           //越小，头抬得越低

     private float current_rotation_H;  //水平旋转结果
     private float current_rotation_V;  //垂直旋转结果
     void LateUpdate()
     {
         // 旋转
         if (Input.GetMouseButton())
         {
             //控制旋转
             current_rotation_H += Input.GetAxis("Mouse X") * rotation_H_speed;
             current_rotation_V += Input.GetAxis("Mouse Y") * rotation_V_speed;
             //current_rotation_V = Mathf.Clamp(current_rotation_V, max_down_angle, max_up_angle);       //限制垂直旋转角度
             transform.localEulerAngles = new Vector3(-current_rotation_V, current_rotation_H, 0f);
             transform.Translate(Vector3.back * distance_h, Space.Self);
             transform.Translate(Vector3.up * distance_v, Space.World);          //相对于世界坐标y轴向上
         }

         // 平移
         if (Input.GetMouseButton())
         {
             this.transform.Translate(new Vector3(-Input.GetAxis("Mouse X") * rotation_H_speed, -Input.GetAxis("Mouse Y") * rotation_V_speed, 0f));
         }
     }
     // Use this for initialization
     void Start()
     {

     }

     // Update is called once per frame
     void Update()
     {
         // 移动
         if (Input.GetKey(KeyCode.A)) //左移
         {
             transform.Translate(Vector3.left * speed * Time.deltaTime);
         }
         if (Input.GetKey(KeyCode.D)) //右移
         {
             transform.Translate(Vector3.right * speed * Time.deltaTime);

         }
         if (Input.GetKey(KeyCode.W)) //前移
         {
             transform.Translate(Vector3.forward * speed * Time.deltaTime);

         }
         if (Input.GetKey(KeyCode.S)) //后移
         {
             transform.Translate(Vector3.back * speed * Time.deltaTime);

         }

         // 缩放
         if (Input.GetAxis("Mouse ScrollWheel") != )
         {
             //获取鼠标滚轮的滑动量
             float wheel = Input.GetAxis("Mouse ScrollWheel") * Time.deltaTime * ;

             //改变相机的位置
             this.transform.Translate(Vector3.forward * wheel);
         }
     }
 }

Camera