css-doodle
Version:
A web component for drawing patterns with CSS
61 lines (55 loc) • 2.57 kB
JavaScript
/**
* Improved noise by Ken Perlin
* Translated from: https://mrl.nyu.edu/~perlin/noise/
*/
const map = [
151,160,137,91,90,15,
131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
190,6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
88,237,149,56,87,174,20,125,136,171,168,68,175,74,165,71,134,139,48,27,166,
77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
102,143,54,65,25,63,161,1,216,80,73,209,76,132,187,208,89,18,169,200,196,
135,130,116,188,159,86,164,100,109,198,173,186,3,64,52,217,226,250,124,123,
5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
223,183,170,213,119,248,152,2,44,154,163,70,221,153,101,155,167,43,172,9,
129,22,39,253,19,98,108,110,79,113,224,232,178,185,112,104,218,246,97,228,
251,34,242,193,238,210,144,12,191,179,162,241,81,51,145,235,249,14,239,107,
49,192,214,31,181,199,106,157,184,84,204,176,115,121,50,45,127,4,150,254,
138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180
];
function lerp(t, a, b) {
return a + t * (b - a);
};
// Convert LO 4 bits of hash code into 12 gradient directions.
function grad(hash, x, y, z) {
let h = hash & 15,
u = h < 8 ? x : y,
v = h < 4 ? y : h == 12 || h == 14 ? x : z;
return ((h&1) == 0 ? u : -u) + ((h&2) == 0 ? v : -v);
}
export default class Perlin {
constructor() {
this.p = [].concat(map, map);
}
noise(x, y, z) {
let { p } = this;
// Find unit cube that contains point.
let [X, Y, Z] = [x, y, z].map(n => Math.floor(n) & 255);
// Find relative x, y, z of point in cube.
[x, y, z] = [x, y, z].map(n => n - Math.floor(n));
// Compute fade curves for each of x, y, z.
let [u, v, w] = [x, y, z].map(n => n * n * n * (n * (n * 6 - 15) + 10));
// hash coordinates of the 8 cube corners.
let A = p[X ]+Y, AA = p[A]+Z, AB = p[A+1]+Z,
B = p[X+1]+Y, BA = p[B]+Z, BB = p[B+1]+Z;
// And add blended results from 8 corners of cube.
return lerp(w, lerp(v, lerp(u, grad(p[AA ], x , y , z ),
grad(p[BA ], x-1, y , z )),
lerp(u, grad(p[AB ], x , y-1, z ),
grad(p[BB ], x-1, y-1, z ))),
lerp(v, lerp(u, grad(p[AA+1], x , y , z-1 ),
grad(p[BA+1], x-1, y , z-1 )),
lerp(u, grad(p[AB+1], x , y-1, z-1 ),
grad(p[BB+1], x-1, y-1, z-1 ))));
}
}