Unity3d：将对象设置为几秒钟不可见

Question

I am using a coroutine to alternate my object visibility using Renderer.enabled every 2 seconds, but the object doesn't wait 2 seconds to change its state, it just alternate between visible and non visible fast and randomly, it's just looking unstable.

Here is my code :

using UnityEngine;
using System.Collections;

public class ArrowController : MonoBehaviour {



GameObject arrow = null;

void Start () {
    arrow = GameObject.Find ("Arrow");
    arrow.GetComponent<Renderer> ().enabled = false;
}

void Update () {

    StartCoroutine(showDirection());


}



    IEnumerator showDirection(){
            while (true) {
        GetComponent<MeshRenderer> ().enabled = true;
        GetComponent<Renderer> ().enabled = true;

        yield return new WaitForSeconds (1);
        GetComponent<MeshRenderer> ().enabled = false;
        GetComponent<Renderer> ().enabled = false;

        yield return new WaitForSeconds (1);
    }

    }


}

Answer 1

That's because you have StartCoroutine in Update method, which is fired every frame. So, you start a new coroutine every frame, and you have hundreds of coroutines running at the same time.

Answer 2

Place that coroutine is start as placing it in update will make the coroutine run many times. Just make sure while using coroutines that they are called only when necessary in you case the keeping it in update loop is the problem.