Fixed number of actions executed randomly in a time window

Unity Engine
,
1

Hello everyone,
as the title suggests, I would like to execute an action 10 times during a time window (1 second). During this period I would like the actions to happen randomly (even some simultaneously would not be a problem) but at the end of each second, an average of 10 actions should be executed.

I did a simple time check using Time.deltaTime and after every second I call the function 10 times, resulting in the actions executing all at the same time, which I do not want.

What I am trying to do is a rainfall “simulation”, where 10 raindrops fall down per second.

    void Update()
    {
        t += Time.deltaTime;
        if (t >= 1.0f) {
            t = t - 1.0f;
            Rain(); //contains a for loop for 10 actions
        }
    }

I do not need a precise solution, so any suggestion is welcomed.
Thank you.

2

In your code above, why not change 1.0f to instead be 0.1f, then make “Rain()” only do one drop?

3

So the idea in that code is to have uniformly spaced drops over time? Basically every 10th of a second 1 should drop? In that case, I think t+=Time.deltaTime*10; would be correct. It will add up to 10 over 1 second, and everytime it hits 1 a drop will fall.

For a random approach, try this logic: suppose you’re at 60FPS. That means we want 60oddsOneDropEachFrame to equal 10, or oddsOneDropEachFrame=10/60. That 1/60 is time.deltaTime, so we get: if(Random.value<=10*Time.deltaTime). A quick test, at 100FPS that gives 100.01 = 0.1.which is a 10% chance each frame. Over 100 frames that should give 10. Another sanity test, what it time.deltaTime*10>1? That means t.dt is 0.1 or more, which means we’re at 10FPS or less. We want a 100% chance for a drop each frame!

1 Like
4

I am sorry I was not clear enough. I wanted the drops falling in the span of 1 second randomly in uniform distribution.

The second approach is what I needed. It did not occur to me to deal with the FPS too.
Thank you very much for all your responses.