Seeded Noise

The goal is to have a way of generating reproducable psuedorandom numbers and noise values with an easy-to-use API.

Really this is an API wrapper for two other libraries:

• seedrandom which will simply generate a random number based on a given seed
• simplex-noise which uses an instance of seedrandom to generate numbers using simplex noise (similar to Perlin noise)

Usage

import { SeededNoise } from 'seeded-noise'

const seed = 123;
const rng = new SeededNoise(seed);

// get a random number between 0 and 1
let rando = rng.random();

// get a random float between 0 and 5
// using the 3d simplex noise algorithm
let noise = rng.noise([1, 2, 3], 0, 5)

// this should yield the same result as
// above because we used the same seed
const rng2 = new SeededNoise(seed);
let rando2 = rng2.random();

API

new SeededRandom([seed], [scale])

The constructor takes 2 arguments:

• seed (optional) will set the seed value for all random numbers. Default is the result of Math.random().
• scale (optional) sets a default value for the noise scale. Default is 1.

random([min], [max])

The API for random is similar to the p5.js random() function.

• min (optional):
  • if 2 arguments are provided it will set the minimum value of the output range
  • if 1 argument is provided it will set the maximum value of an output range starting with 0
• max (optional) will set the maximum value of the output range

If no argumants are provided then this method will return a number between 0 and 1.

Examples

// return a random number between 0 and 1
rng.random();

// return a random number between 0 and 5
rng.random(5);

// return a random number between 5 and 10
rng.random(5, 10);

noise(input, [min], [max], [scale])

The noise method works similar to the random method, but also requires an array of 2-4 numbers as its first argument.

• input (required) is an array containing 2, 3, or 4 numbers that will be used as the basis for the noise result
• min (optional) same as above
• max (optional) same as above
• scale (optional) will set the scale of the noise results

Examples

// return value between 0 and 1 using 2d simplex noise
rng.noise([1, 2]);

// 3d noise
rng.noise([3, 4, 5]);

// 4d noise
rng.noise([6, 7, 8, 9]);

// 3d noise value between 0 and 5
rng.noise([3, 4, 5], 5);

// 3d noise value between 5 and 10
rng.noise([3, 4, 5], 5, 10);

// 3d noise value between 0 and 1, scaled up to 10
rng.noise([3, 4, 5], 0, 1, 10);