Coroutine does no play all the way through

Question

Unfortunately my co routine does not play all the way through. It is supposed to fade an object so it's alpha is 0. However it fades to .039.

{
    StartCoroutine(colorlerpin7());
    yield return null;
}

public IEnumerator colorlerpin7()

{
    float ElapsedTime = 0.0f;
    float TotalTime = 1f;
    while (ElapsedTime < TotalTime)

    {
        //  fades out atipical
        ElapsedTime += Time.deltaTime;
        fluidpef.GetComponent<Renderer>().material.color = Color.Lerp(new 
        Color(1f, 1f, 1f, 1f), new Color(1f, 1f, 1f, 0f), (ElapsedTime / 
        TotalTime));
        yield return null;

    }
}

score 1 · Accepted Answer · answered Apr 23 '19 at 12:32

1

this looks like the "correct" behaviour since your ElapsedTime will be bigger then TotalTime before you will get to an alpha of 0 (or a lerp value of 1) e.g.

->frame x ElapsedTime is 0.97 your lerp value is 0.97.

->frame x+1 ElapsedTime might be already 1.1, so you will jump out of the loop.

Just add this code after the loop:

fluidpef.GetComponent<Renderer>().material.color = Color.Lerp(new 
    Color(1f, 1f, 1f, 1f), new Color(1f, 1f, 1f, 0f), 1);

answered Apr 23 '19 at 12:32

Jack10689

181
4

1

In this case you won't even need the Lerp function though, you could just force the value to `new Color(1f, 1f, 1f, 0f)` – Saeleas Apr 23 '19 at 12:34
Yes, absolutely. – Jack10689 Apr 23 '19 at 13:10

Saeleas · Answer 2 · 2019-04-23T12:57:52.670

1

The while condition is why the alpha value does not decrease to 0. ElapsedTime < TotalTime means that in your loop ElapsedTime / TotalTime will never be equal to 1, meaning that the value of alpha will not be 0.

To solve it I would change the condition to check the alpha value of the material:

public IEnumerator colorlerpin7()

{
    float ElapsedTime = 0.0f;
    float TotalTime = 1f;
    Renderer matRenderer =  fluidpef.GetComponent<Renderer>();
    while (matRenderer.material.color.a > 0.0f)

    {
        ElapsedTime += Time.deltaTime;
        matRenderer.material.color = Color.Lerp(new 
        Color(1f, 1f, 1f, 1f), new Color(1f, 1f, 1f, 0f), (ElapsedTime / 
        TotalTime);
        yield return null;

    }
}

edited Apr 23 '19 at 12:57

answered Apr 23 '19 at 12:41

Saeleas

538
2
8

`Color.Lerp` will do clamp for you. – shingo Apr 23 '19 at 12:50
`Color.Lerp` clamps the third paramenter, not the color value, so your code will get the same result as the OP's. I think his problem is not about the clamp. – shingo Apr 23 '19 at 12:57
I updated my answer, sorry for the trouble. The problem, as already noted, is in the `while` that ends a frame too early. In this answer I change the condition to check on the alpha value instead of the `ElapsedTime` – Saeleas Apr 23 '19 at 13:01

Coroutine does no play all the way through

2 Answers2