fast-simplex-noise
Version:
A TypeScript implementation of faster simplex noise
133 lines (132 loc) • 4.56 kB
JavaScript
"use strict";
/*
* Based on example code by Stefan Gustavson (stegu@itn.liu.se).
* Optimisations by Peter Eastman (peastman@drizzle.stanford.edu).
* Better rank ordering method by Stefan Gustavson in 2012.
*
* This code was placed in the public domain by its original author,
* Stefan Gustavson. You may use it as you see fit, but
* attribution is appreciated.
*/
Object.defineProperty(exports, "__esModule", { value: true });
exports.makeNoise3D = void 0;
var G3 = 1.0 / 6.0;
var Grad = [
[1, 1, 0],
[-1, 1, 0],
[1, -1, 0],
[-1, -1, 0],
[1, 0, 1],
[-1, 0, 1],
[1, 0, -1],
[-1, 0, -1],
[0, 1, 1],
[0, -1, -1],
[0, 1, -1],
[0, -1, -1],
];
function makeNoise3D(random) {
if (random === void 0) { random = Math.random; }
var p = new Uint8Array(256);
for (var i = 0; i < 256; i++)
p[i] = i;
var n;
var q;
for (var i = 255; i > 0; i--) {
n = Math.floor((i + 1) * random());
q = p[i];
p[i] = p[n];
p[n] = q;
}
var perm = new Uint8Array(512);
var permMod12 = new Uint8Array(512);
for (var i = 0; i < 512; i++) {
perm[i] = p[i & 255];
permMod12[i] = perm[i] % 12;
}
return function (x, y, z) {
// Skew the input space to determine which simplex cell we're in
var s = (x + y + z) / 3.0; // Very nice and simple skew factor for 3D
var i = Math.floor(x + s);
var j = Math.floor(y + s);
var k = Math.floor(z + s);
var t = (i + j + k) * G3;
var X0 = i - t; // Unskew the cell origin back to (x,y,z) space
var Y0 = j - t;
var Z0 = k - t;
var x0 = x - X0; // The x,y,z distances from the cell origin
var y0 = y - Y0;
var z0 = z - Z0;
// Deterine which simplex we are in
var i1, j1, k1 // Offsets for second corner of simplex in (i,j,k) coords
;
var i2, j2, k2 // Offsets for third corner of simplex in (i,j,k) coords
;
if (x0 >= y0) {
if (y0 >= z0) {
i1 = i2 = j2 = 1;
j1 = k1 = k2 = 0;
}
else if (x0 >= z0) {
i1 = i2 = k2 = 1;
j1 = k1 = j2 = 0;
}
else {
k1 = i2 = k2 = 1;
i1 = j1 = j2 = 0;
}
}
else {
if (y0 < z0) {
k1 = j2 = k2 = 1;
i1 = j1 = i2 = 0;
}
else if (x0 < z0) {
j1 = j2 = k2 = 1;
i1 = k1 = i2 = 0;
}
else {
j1 = i2 = j2 = 1;
i1 = k1 = k2 = 0;
}
}
var x1 = x0 - i1 + G3; // Offsets for second corner in (x,y,z) coords
var y1 = y0 - j1 + G3;
var z1 = z0 - k1 + G3;
var x2 = x0 - i2 + 2.0 * G3; // Offsets for third corner in (x,y,z) coords
var y2 = y0 - j2 + 2.0 * G3;
var z2 = z0 - k2 + 2.0 * G3;
var x3 = x0 - 1.0 + 3.0 * G3; // Offsets for last corner in (x,y,z) coords
var y3 = y0 - 1.0 + 3.0 * G3;
var z3 = z0 - 1.0 + 3.0 * G3;
// Work out the hashed gradient indices of the four simplex corners
var ii = i & 255;
var jj = j & 255;
var kk = k & 255;
var g0 = Grad[permMod12[ii + perm[jj + perm[kk]]]];
var g1 = Grad[permMod12[ii + i1 + perm[jj + j1 + perm[kk + k1]]]];
var g2 = Grad[permMod12[ii + i2 + perm[jj + j2 + perm[kk + k2]]]];
var g3 = Grad[permMod12[ii + 1 + perm[jj + 1 + perm[kk + 1]]]];
// Calculate the contribution from the four corners
var t0 = 0.5 - x0 * x0 - y0 * y0 - z0 * z0;
var n0 = t0 < 0
? 0.0
: Math.pow(t0, 4) * (g0[0] * x0 + g0[1] * y0 + g0[2] * z0);
var t1 = 0.5 - x1 * x1 - y1 * y1 - z1 * z1;
var n1 = t1 < 0
? 0.0
: Math.pow(t1, 4) * (g1[0] * x1 + g1[1] * y1 + g1[2] * z1);
var t2 = 0.5 - x2 * x2 - y2 * y2 - z2 * z2;
var n2 = t2 < 0
? 0.0
: Math.pow(t2, 4) * (g2[0] * x2 + g2[1] * y2 + g2[2] * z2);
var t3 = 0.5 - x3 * x3 - y3 * y3 - z3 * z3;
var n3 = t3 < 0
? 0.0
: Math.pow(t3, 4) * (g3[0] * x3 + g3[1] * y3 + g3[2] * z3);
// Add contributions from each corner to get the final noise value.
// The result is scaled to stay just inside [-1,1]
return 94.68493150681972 * (n0 + n1 + n2 + n3);
};
}
exports.makeNoise3D = makeNoise3D;