Coroutine lasts longer than expected

[YoungBreath]

Hello everyone, here I have something that peeked my interest when working with the Coroutines.
So I’m drawing a line using the “LineRenderer”, The points of the line are inside a list and the number of points can vary. Nevertheless I want the process to last on second in total to be drawn.
With this in mind I though about working with a Coroutine and using WaitForSecondsRealtime(). My logic is that each point will be drawn in between segments of time equals to “1/NumberOfPoints”, So I wrote the next piece of code:

IEnumerator drawingAnimation()
    {
        float timePerSegment = 1f/availablePath.Count;
        int lineIndex = 0;
        for(int i = availablePath.Count-1; i >=0 ;i--)
        {
            pencil.positionCount++;
            pencil.SetPosition(lineIndex, mazeCells[availablePath[i]].transform.position + Vector3.up * (wallHeight +2));
            lineIndex++;
            yield return new WaitForSecondsRealtime(timePerSegment);
        }
        drawingRoutin = null;
        Debug.Log("Finished Drawing Line");
    }

The process runs fine, but it takes longer than one second to be completed.In fact I decided to have another Coroutine taking the time for this process to be completed, Here is a screen capture:

Here is some more data regarding this results:
The total number of points in the list is 170.
timePerSegment = 0.005882353

Now my questions are:
Why do you think the process takes more than what I expect it to take?
Am I not taking something into consideration? (regarding the WaitForSecondsRealTime())

[Kurt-Dekker]

You will never get 170 updates completed in one second. It will never exceed the rate at which Update() is being called.

See the Unity lifecycle graph for a feeling on when coroutines are updated relative to Update. Specifically only “one step” of the coroutine is called.

Unity - Manual: Order of execution for event functions

It is up to you to do the bookkeeping to “make this so,” but it’s not too hard. You can just do a “yield return null;” (which says “always run me the next frame”) and then query Time.deltaTime to see how much time actually passed, then do the required number of your 1 / 170th second steps to meet up.

[YoungBreath]

@Kurt-Dekker

You will never get 170 updates completed in one second. It will never exceed the rate at which Update() is being called.

See the Unity lifecycle graph for a feeling on when coroutines are updated relative to Update. Specifically only “one step” of the coroutine is called.

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

It is up to you to do the bookkeeping to “make this so,” but it’s not too hard. You can just do a “yield return null;” (which says “always run me the next frame”) and then query Time.deltaTime to see how much time actually passed, then do the required number of your 1 / 170th second steps to meet up.

Interesting, I’ll have a complete read on the execution order and I will give a go on the book keeping. As you said it really does not seem like something out of the world.