Are co-routines updated every Update/FixedUpdate or neither?

Say I have a coroutine:

Code (CSharp):

1. IEnumerator<int> Fade(){
2.         Debug.Log ("Fade");
3.         while(speechBubble.renderer.material.color.a>0){
4.             Color c=speechBubble.renderer.material.color;
5.             c.a -= Time.deltaTime;
6.             speechBubble.renderer.material.color = c;
7.             yield return 0;
8.         }
9.         Debug.Log ("Fade done");
10.     }

Will this get updated every frame? Every FixedUpdate? Or none of the above? If so should I use Time.fixedDeltaTime or neither?

Thanks.

 

Coroutines run after the update

https://docs.unity3d.com/Manual/ExecutionOrder.html

 

OK cool. So I can use them just like something in the update function.

 

@yoonitee for a coroutine to actually give up control, so Unity can draw a frame, then return to the coroutine, you need to put in yield return null; or yield return new WaitForEndOfFrame(); otherwise the coroutine will just continue until it ends without ever giving Unity a change to draw anything to screen.

Edit: I guess your yield return 0; is doing the same thing? My coroutines usually return type IEnumerator and not IEnumerator<int>.

 

I'm using System.Collections.Generic. It doesn't let me return a null as far as I can see.

 

Another handy pattern is that you can define your void Start() function to instead return IEnumerator, and then it is inherently a coroutine.

 

Coroutines should all be of type System.Collections.IEnumerator

It used to be the case that yielding anything besides null resulted in a memory allocation but that may have been fixed.

 

Yield return null will wait for the next frame. Yeild return new WaitForFixedUpdate() will wait for the next physics update.

 

Thanks. Useful info!! Now I'm ready to overuse co-routines to my hearts content.