Retro Random

A random number generator for an old school video game feel

For old, 8-bit video games, random numbers were a bit more difficult for computers, and the randomness was somewhat predictable.

If your looking to build a video game, and want that old retro feel, this random number generator can help.

This module attempts to generate predictable results, while still being unique.

This random number generator also allows seeds. By default, the random seed is the current time in milliseconds. The seed can be used to generate consistant results for a game level, but the output will still be slightely different. Using the same seed adds a higher chance of getting the same output the first time twice.

There should be about an 82% chance of getting the same number on the first call of the same seed, and only a 42% chance of getting the same number on the next call.

Installation

node.js

npm install retro-random

cdn

<script src="https://cdn.jsdelivr.net/gh/AspieSoft/retro-random-number@1.2.1/script.min.js"></script>

Usage

// require only if using node.js
const RetroRandom = require('retro-random');


// create a new instance with a random time based seed
let r = RetroRandom();

// create a new instance with a specific seed
let r = RetroRandom(1234567890);

// create a new instance with consistant results when recreated from the same seed
let r = RetroRandom(1234567890, true);

// new instance that uses the time the function was called in place of Math.random()
let r = RetroRandom(1234567890, 1);

// divide time by 1000 (base on time in seconds instead of milliseconds)
let r = RetroRandom(1234567890, 1000);

// use a preset start time in place of the time the function was called
let r = RetroRandom(1234567890, 5, 1658107066981 /* Date.now() */);
// this last example can also return consistant results when recreated with the same data


r(0, 1000); // pick a random number between 0 and 1000

r(-20, 50); // pick a random number between -20 and 50

r(0, 1, 3); // pick a random number between 0 and 1 with a 0 to 3 digit decimal

r(0, 1, 3, 2); // pick a random number between 0 and 1 with a 2 to 3 digit decimal

r(0, 1, 3, 3); // pick a random number between 0 and 1 with exactly a 3 digit decimal


r.origSeed() // return the original seed (output: 1234567890)

r.seed() // return a new seed that starts where you left off (output may very)

r.startTime() // return the time passed in the 3rd param on init or the time the function was initialized

r.callTime() // return the time thr function was initialized