How do I make this coroutine run every 3 seconds?

I need this gameObject to instantiate another GameObject every three seconds without stopping. I'm just learning coroutines and need help understanding the different yield returns and I couldn't find a section in a Unity manual about yield returns.

Here is what I need to run:

Code (CSharp):

1. IEnumerator DropAttack()
2.     {
3.         yield return new WaitForSeconds(3);
4.          GameObject TrapAttack = Instantiate(SpikerPrefab, Dropper.position, Dropper.rotation);
5.      
6.     }

 

That coroutine is correct for waiting 3 seconds and spawning once. You can make a small tweak to make it do this in a loop forever:

Code (csharp):

1.  
2. IEnumerator DropAttack()
3.     {
4.         while (true) {
5.              yield return new WaitForSeconds(3);
6.              GameObject TrapAttack = Instantiate(SpikerPrefab, Dropper.position, Dropper.rotation);
7.          }
8.     }

(Note: be a little bit careful when using a while loop - if you accidentally remove the "yield" line from inside the loop, you'll hard-freeze Unity, because it will never escape the loop.)

To start this, call StartCoroutine(DropAttack()); .... Make sure you only call this once (e.g. in Start()). If you call it repeatedly (e.g. in Update(), if you don't have conditions on it to keep it from being called more than once), you'll get hundreds and hundreds of these coroutines running in parallel.

 

Thank you very much that makes a lot of sense; now i'm just wondering why I couldn't figure that out on my own.

 

I had the while freeze before - I also forgot to save my scene.
Why does while(true) return as true in this case?

 

A infinite while loop in a Coroutine will cause a freeze. Make sure that you are yielding somewhere in the while loop.

 

As a personal note and to reduce garbage, NEVER create a new "WaitForSeconds" every loop. Create a reference and reuse it

Code (CSharp):

1.         private WaitForSeconds refreshIntervalWait = new WaitForSeconds(3);
2.         private IEnumerator DropAttack()
3.         {
4.              while (true)
5.             {
6.                 yield return refreshIntervalWait;
7.                 GameObject TrapAttack = Instantiate(SpikerPrefab, Dropper.position, Dropper.rotation);
8.             }
9.         }