Why random() repeats

Programming Questions

chuchuchu

in Programming Questions • 10 months ago

Hello!

Can anyone tell me why random() here seems to repeat? I would like the ellipse height and width to be between 0-200, it seems to keep making new values leading to odd animation.

void setup() {
    size(800, 800);
    ellipseMode(CENTER);
    smooth();
}

void draw() {
    background(255);
    ellipse( width/2, height/2, random(200), random(200));
}

I know this is prob really simple but can't find an answer.

Many Thanks!

Replies(4)

v.k.

Re: Why random() repeats

10 months ago

draw() is called 60 times per second, each time random is called it gets a new value.

You might just move it to setup() passing it to a variable and using it in draw, like:

EDITED to correct as pointed by GoToLoop

In Global scope (outside any function):

float s = random(200);

In draw:

ellipse(x, y, s, s);

Or,

For this simple example you could do all in setup.

ellipse( width/2, height/2, random(200), random(200));

Will be the same.

GoToLoop

I guess float s = random(200); has to be moved outside any function.
So it becomes a global variable.

A variable declared inside a scope, dies when that scope finishes!

For example -> a variable declared inside setup(), just exists inside that!
It can't be used inside draw() or any other function!

v.k.

Re: Why random() repeats

10 months ago

Yep, thanks for pointing GoToLoop. My bad. I'll edit that. :)

chuchuchu

Re: Why random() repeats

9 months ago

Hey forgot to say thanks for helping me out here! Processing is like a wormhole and i got sucked in ;-)

Thanks!

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