Unity3D实现异步加载场景

实现异步加载场景不仅需要当前场景和目标场景，同时还需要一个中间场景实现目标场景的加载过程。

对于中间场景的构建可添加进度条（slider组件）和进度显示（Text组件）。同时在MainCamera上挂在脚本内容如下：

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

public class SceneControl
{
    public static string targetSceneName;
    public static void LoadScene(string sceneName)
    {
        targetSceneName = sceneName;
        SceneManager.LoadScene("MiddleScene");
    }
}

public class LoadScene : MonoBehaviour
{
    //将Slider组件拖入此位置
    public Slider loadingSlider;
    //将Text组件拖入此位置
    public Text loadingText;

    private float loadingSpeed = 0.4f;

    private float targetValue;

    private AsyncOperation operation;

    // Use this for initialization
    void Start()
    {
        StartCoroutine(AsyncLoading());
    }

    IEnumerator AsyncLoading()
    {
        operation = SceneManager.LoadSceneAsync(SceneControl.targetSceneName);
        //阻止当加载完成自动切换
        operation.allowSceneActivation = false;
        yield return operation;
    }

    // Update is called once per frame
    void Update()
    {
        targetValue = operation.progress;

        if (operation.progress >= 0.9f)
        {
            //operation.progress的值最大为0.9
            targetValue = 1.0f;
        }

        if (targetValue != loadingSlider.value)
        {
            loadingSlider.value = Mathf.MoveTowards(loadingSlider.value, targetValue, Time.deltaTime * loadingSpeed);
        }
        loadingText.text = ((int)(loadingSlider.value * 100)).ToString() + "%";

        if ((int)loadingSlider.value == 1)
        {
            //允许异步加载完毕后自动切换场景
            operation.allowSceneActivation = true;
        }
    }
}

在当前场景中使用SceneControl.LoadScene(string sceneName)静态方法就可以加载目标场景。