@woosh/meep-engine/src/core/math/hash/squirrel3.js

Pure JavaScript game engine. Fully featured and production ready.

const BIT_NOISE1 = 0xB5297A4D;
const BIT_NOISE2 = 0x68E31DA4;
const BIT_NOISE3 = 0x1B56C4E9;

/**
 * Based on Squirrel3 hash function by Squirrel Eiserloh
 * Alex: Personally I found it to have low entropy, so I don't see it as very useful
 * @see GDC 2017 presentation on "Math for Game Programmers: Noise-Based RNG"
 * @param {number} value expected to be an integer, if not - it will be truncated to such
 * @returns {number} signed 32-bit integer
 */
export function squirrel3(value) {
    let hash = value * BIT_NOISE1;

    hash ^= (hash >> 8);
    hash += BIT_NOISE2;
    hash ^= (hash << 8);
    hash *= BIT_NOISE3;
    hash ^= (hash >> 8);

    return hash;
}