randomNoise = { const PERLIN_YWRAPB = 4; const PERLIN_YWRAP = 1 << PERLIN_YWRAPB; const PERLIN_ZWRAPB = 8; const PERLIN_ZWRAP = 1 << PERLIN_ZWRAPB; const PERLIN_SIZE = 4095; function scaledCosine(i) { return 0.5 * (1.0 - Math.cos(i * Math.PI)); } function randomLcg(seed) { const m = 4294967296; const a = 1664525; const c = 1013904223; let z = (seed == null ? Math.random() * m : seed) >>> 0; return () => { z = (a * z + c) % m; return z / m; }; } function noiseSeed(seed) { const random = randomLcg(seed); const perlin = new Array(PERLIN_SIZE + 1); for (let i = 0; i < PERLIN_SIZE + 1; i++) { perlin[i] = random(); } return perlin; } // Adapting from P5.js // @see https://github.com/processing/p5.js/blob/1e6b0caa1e8a8dff3280917d2fd9a84d2e7126ba/src/math/noise.js#L200 return function randomNoise( lo = 0, hi = 1, { octaves = 4, seed = d3.randomUniform(100000)(), falloff = 0.5 } = {} ) { const map = d3.scaleLinear([0, 1], [lo, hi]); const perlin = noiseSeed(seed); const noise = (x, y = 0, z = 0) => { if (x < 0) x = -x; if (y < 0) y = -y; if (z < 0) z = -z; let xi = Math.floor(x), yi = Math.floor(y), zi = Math.floor(z); let xf = x - xi; let yf = y - yi; let zf = z - zi; let rxf, ryf; let r = 0; let ampl = 0.5; let n1, n2, n3; for (let o = 0; o < octaves; o++) { let of = xi + (yi << PERLIN_YWRAPB) + (zi << PERLIN_ZWRAPB); rxf = scaledCosine(xf); ryf = scaledCosine(yf); n1 = perlin[of & PERLIN_SIZE]; n1 += rxf * (perlin[(of + 1) & PERLIN_SIZE] - n1); n2 = perlin[(of + PERLIN_YWRAP) & PERLIN_SIZE]; n2 += rxf * (perlin[(of + PERLIN_YWRAP + 1) & PERLIN_SIZE] - n2); n1 += ryf * (n2 - n1); of += PERLIN_ZWRAP; n2 = perlin[of & PERLIN_SIZE]; n2 += rxf * (perlin[(of + 1) & PERLIN_SIZE] - n2); n3 = perlin[(of + PERLIN_YWRAP) & PERLIN_SIZE]; n3 += rxf * (perlin[(of + PERLIN_YWRAP + 1) & PERLIN_SIZE] - n3); n2 += ryf * (n3 - n2); n1 += scaledCosine(zf) * (n2 - n1); r += n1 * ampl; ampl *= falloff; xi <<= 1; xf *= 2; yi <<= 1; yf *= 2; zi <<= 1; zf *= 2; if (xf >= 1.0) { xi++; xf--; } if (yf >= 1.0) { yi++; yf--; } if (zf >= 1.0) { zi++; zf--; } } return r; }; return (x0 = 0, y0 = 0, z0 = 0) => { const t = map(noise(x0, y0, z0)); return t; }; }; }