Unity 异步加载场景，进度条显示

using UnityEngine;
using System.Collections;
using UnityEngine.UI;
using UnityEngine.SceneManagement;

public class Globe
{
    public static string nextSceneName;
}

public class AsyncLoadScene : MonoBehaviour
{
    public Text loadingText;
    public Image progressBar;

    private int curProgressValue = 0;

    private AsyncOperation operation;

    // Use this for initialization
    void Start()
    {
　　　　　　//加载的场景名称
        Globe.nextSceneName = "Main_Day";

        if (SceneManager.GetActiveScene().name == "Main")
        {
            //启动协程
            StartCoroutine(AsyncLoading());
        }
      
    }

    IEnumerator AsyncLoading()
    {
       
        operation = SceneManager.LoadSceneAsync(Globe.nextSceneName);
        Debug.Log(operation.progress);
        //阻止当加载完成自动切换
        operation.allowSceneActivation = false;

        yield return operation;
    }

    void Update()
    {

        curProgressValue = (int)(operation.progress * 100);

        loadingText.text = curProgressValue + "%";//实时更新进度百分比的文本显示  

        progressBar.fillAmount = curProgressValue / 100f;//实时更新滑动进度图片的fillAmount值  

        //operation.progress 在这最大值为0.89（有的是0.9）
        if (operation.progress >=0.89)
        {
            operation.allowSceneActivation = true;//启用自动加载场景  
           
        }
    }
}