10.协程

可以理解为按时间间隔执行的函数
协程的返回类型IEnumerator表示可以返回实现IEnumerator接口的任意内容
yield return null;协程会正常执行，表示将函数执行并且返回空的IEnumerator；当返回值为null（或任意数字），表示将在下一个更新继续执行（即下一帧）
使用协程避免在update中使用计时器，与属性结合发挥更大作用。

CoroutinesExample

public class CoroutinesExample : MonoBehaviour
{
    public float smoothing = 1f;
    public Transform target;
    void Start ()
    {
        StartCoroutine(MyCoroutine(target));
    }
    IEnumerator MyCoroutine (Transform target)
    {
        while(Vector3.Distance(transform.position, target.position) > 0.05f)
        {
            transform.position = Vector3.Lerp(transform.position, target.position, smoothing * Time.deltaTime);
            yield return null;
        }
        print("Reached the target.");
        yield return new WaitForSeconds(3f);
        print("MyCoroutine is now finished.");
    }
}

PropertiesAndCoroutines

public class PropertiesAndCoroutines : MonoBehaviour
{
    public float smoothing = 7f;
    public Vector3 Target
    {
        get { return target; }
        set
        {
            target = value;
            StopCoroutine("Movement");
            StartCoroutine("Movement", target);
        }
    }
    private Vector3 target;
    IEnumerator Movement (Vector3 target)
    {
        while(Vector3.Distance(transform.position, target) > 0.05f)
        {
            transform.position = Vector3.Lerp(transform.position, target, smoothing * Time.deltaTime);
            yield return null;
        }
    }
}

ClickSetPosition

public class ClickSetPosition : MonoBehaviour
{
    public PropertiesAndCoroutines coroutineScript;
    void OnMouseDown ()
    {
        Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
        RaycastHit hit;
        Physics.Raycast(ray, out hit);
        if(hit.collider.gameObject == gameObject)
        {
            Vector3 newTarget = hit.point + new Vector3(0, 0.5f, 0);
            coroutineScript.Target = newTarget;
        }
    }
}

停止协程

我们可以使用函数名StartCoroutine(“函数名”)或是方法StartCoroutine(方法())来开启协程，但是直接用StopCoroutine(方法())和StopCoroutine(“函数名”)不能关闭协程
关闭的方法

• StopAllCoroutines();

• Coroutine coroutine = StartCoroutine(“函数名”); 或 Coroutine coroutine = StartCoroutine(方法());先记录一下

  再**StopCoroutine(coroutine); **