Unity3D场景中对模型旋转放大缩小脚本

using UnityEngine;
using System.Collections;

public class Radio_Operation1 : MonoBehaviour
{

    #region//相关参数初始化
    public Transform target;
    public  int MouseWheelSensitivity = 1;
    private int MouseZoomMin = 1;
    private int MouseZoomMax = 5;
    private float normalDistance = 3;

    private Vector3 normalized;
    private float xSpeed = 250.0f;
    private float ySpeed = 120.0f;

    private int yMinLimit = -20;
    private int yMaxLimit = 80;

    private float x = 0.0f;
    private float y = 0.0f;

    private Vector3 screenPoint;
    private Vector3 offset;
    private Quaternion rotation = Quaternion.Euler（new Vector3（30f 0f 0f））;
    private Vector3 CameraTarget;
    private GUIstyle style_opration = new GUIstyle（）;
    public GUISkin CustomSkin;
    private GUIstyle ziti = new GUIstyle（）;
    //private Rect windowRect0 = new Rect（Screen.width * 11 / 35 Screen.height * 11 / 28 285 200）;
    private Rect windowRect0 = new Rect（0 0 285 200）;
    #endregion

    #region//Start-初始化函数
    void Start （） {
        CameraTarget = target.position;

        float z = target.transform.position.z - normalDistance;
        transform.position = rotation * new Vector3（transform.position.x transform.position.y z）;

        transform.LookAt（target）;

        var angles = transform.eulerAngles;
        x = angles.y;
        y = angles.x;
	
	}
    #endregion

    #region//Updata-函数
    void Update （） {
        if（Input.GetMouseButton（1））
                {
                        x += Input.GetAxis（“Mouse X“） * xSpeed * 0.02f;
                        y -= Input.GetAxis（“Mouse Y“） * ySpeed * 0.02f;

                        y = ClampAngle（y yMinLimit yMaxLimit）;
 
                        var rotation = Quaternion.Euler（y x 0）;
                        var position = rotation * new Vector3（0.0f 0.0f -normalDistance） + CameraTarget;
 
                        transform.rotation = rotation;
                        transform.position = position;
 
                }else if （Input.GetAxis（“Mouse ScrollWheel“） != 0）
                {
                    normalized = （transform.position - CameraTarget）.normalized;
 
                        if （normalDistance >= MouseZoomMin && normalDistance <= MouseZoomMax）
                        {
                                normalDistance -= Input.GetAxis（“Mouse ScrollWheel“） * MouseWheelSensitivity;
                        }
                        if （normalDistance < MouseZoomMin）
                        {
                                normalDistance = MouseZ