Random to initialize variables

[davidhurwich]

I have a question. I’ve noticed that when I initialize variables with a value before setup(); or draw(); that it works for a string, boolean, number.

However, if I try to set that value to a random number using random() it will not work outside of setup(); or draw(). Why is it that functions do not work outside of setup() or draw()?

Any information would be appreciated.

[Sven]

Welcome to the forum, @davidhurwich!

Technically, p5.js is not ready when that variable is initialized. So random() is not available to be called. If you take a look at the JavaScript console in your browser’s developer tools, you’ll probably see an error like ReferenceError: Can't find variable: random.

You could get a random number by using vanilla JavaScript instead: Math.random(). Or use this workaround:

new p5();

var boop = random(100);

function setup() {
    createCanvas(100, 100);
}

function draw() {
    background(255, 0, boop);
}

Source: Why can’t I assign variables using p5 functions and variables before setup()?

[GoToLoop]

@davidhurwich

Why is it that functions do not work outside of setup() or draw()?

When can you use cos and sin outside of setup or draw

I’ve changed your post to the p5.js forum category then. p5js is a diff. flavor beast. Indeed, none of its API is available until either it finds out that setup() or draw() is in the global context (window) or we manually instantiate class p5: new p5; new p5; // prematurely instantiate class p5. ;-) const SQRT_3 = sqrt(3); // we can access p5's sqrt() method outside functions! function setup() { print(SQRT_3); } For cos() & sin() and similar, we …