noise.js

// Perlin Noise JS
// From Daniel Shiffman

// Ported from: http://mrl.nyu.edu/~perlin/noise/
// http://mrl.nyu.edu/~perlin/paper445.pdf

module.exports = Perlin;

function Perlin() {
  this.p = [];
  for (var i=0; i < 256 ; i++) {
    this.p[256+i] = this.p[i] = this.permutation[i];
  }
};

Perlin.prototype.p;
Perlin.prototype.permutation = [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
   ];

Perlin.prototype.noise = function(x, y, z) {

  // This is probably not how you are supposed to do this
  y = y || 0;
  z = z || 0;

  var X = Math.floor(x) & 255;                       // FIND UNIT CUBE THAT
  var Y = Math.floor(y) & 255;                       // CONTAINS POINT.
  var Z = Math.floor(z) & 255;
  x -= Math.floor(x);                                // FIND RELATIVE X,Y,Z
  y -= Math.floor(y);                                // OF POINT IN CUBE.
  z -= Math.floor(z);

  var u = this.fade(x);                                   // COMPUTE FADE CURVES
  var v = this.fade(y);                                   // FOR EACH OF X,Y,Z.
  var w = this.fade(z);
  var A = this.p[X  ]+Y, AA = this.p[A]+Z, AB = this.p[A+1]+Z;      // HASH COORDINATES OF
  var B = this.p[X+1]+Y, BA = this.p[B]+Z, BB = this.p[B+1]+Z;      // THE 8 CUBE CORNERS,

  return this.lerp(w, this.lerp(v, this.lerp(u, this.grad(this.p[AA  ], x  , y  , z   ),  // AND ADD
                                                this.grad(this.p[BA  ], x-1, y  , z   )), // BLENDED
                                   this.lerp(u, this.grad(this.p[AB  ], x  , y-1, z   ),  // RESULTS
                                                this.grad(this.p[BB  ], x-1, y-1, z   ))),// FROM  8
                      this.lerp(v, this.lerp(u, this.grad(this.p[AA+1], x  , y  , z-1 ),  // CORNERS
                                                this.grad(this.p[BA+1], x-1, y  , z-1 )), // OF CUBE
                                  this.lerp(u,  this.grad(this.p[AB+1], x  , y-1, z-1 ),
                                                this.grad(this.p[BB+1], x-1, y-1, z-1 ))))*0.5+0.5;
};

Perlin.prototype.fade = function(t)        { return t * t * t * (t * (t * 6 - 15) + 10); }
Perlin.prototype.lerp = function(t, a, b) { return a + t * (b - a); }
Perlin.prototype.grad = function(hash, x, y, z) {
  var h = hash & 15;                      // CONVERT LO 4 BITS OF HASH CODE
  var u = h<8 ? x : y;                    // INTO 12 GRADIENT DIRECTIONS.
  var v = h<4 ? y : h==12||h==14 ? x : z;
  return ((h&1) == 0 ? u : -u) + ((h&2) == 0 ? v : -v);
}


// Seeding needs to be implemented
// This is from: https://gist.github.com/leegrey/3253283
// Based on: http://techcraft.codeplex.com/discussions/264014

Perlin.prototype.setSeed = function( seed ) {
  seed = seed || 1337;
  this.permutation = []; //make permutation unique between instances
  if( SeededRandomNumberGenerator == undefined ) {
    console.log( 'Perlin.setSeed() - warning,'
      +' SeededRandomNumberGenerator is undefined' );
    return;
  }
  var seedRND = new SeededRandomNumberGenerator();
  seedRND.seed = seed;
  var i;
  for ( i = 0; i < 256; i++)  {
    this.permutation[i] = i;
  }
  for (  i = 0; i < 256; i++) {
    var k = seedRND.randomIntRange( 0, 256 - i ) + i; //(256 - i) + i;
    var l = this.permutation[i];
    this.permutation[i] = this.permutation[k];
    this.permutation[k] = l;
    this.permutation[i + 256] = this.permutation[i];
  }
  for (var i = 0; i < 256 ; i++) {
    this.p[256+i] = this.p[i] = this.permutation[i];
  }
};

var SeededRandomNumberGenerator = function (seed, m, n) {
  if (!(this instanceof SeededRandomNumberGenerator)) {
    return new SeededRandomNumberGenerator(seed, m, n);
  }
  this.m = m || 82947121839;
  this.n = n || 328347242343;
  this.seed = seed || 1337;
};

SeededRandomNumberGenerator.prototype.randomIntRange = function (start, end) {
  this.seed = (this.seed * this.n) % this.m;
  return this.seed % (start - end) + start;
};