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two Perlin noise generators in javascript. The simplex version is about 10% faster (in Chrome at least, haven't tried other browsers)

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perlin-noise-classical.js
JavaScript
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// Ported from Stefan Gustavson's java implementation
// http://staffwww.itn.liu.se/~stegu/simplexnoise/simplexnoise.pdf
// Read Stefan's excellent paper for details on how this code works.
//
// Sean McCullough banksean@gmail.com
 
/**
* You can pass in a random number generator object if you like.
* It is assumed to have a random() method.
*/
var ClassicalNoise = function(r) { // Classic Perlin noise in 3D, for comparison
if (r == undefined) r = Math;
this.grad3 = [[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]];
this.p = [];
for (var i=0; i<256; i++) {
this.p[i] = Math.floor(r.random()*256);
}
// To remove the need for index wrapping, double the permutation table length
this.perm = [];
for(var i=0; i<512; i++) {
this.perm[i]=this.p[i & 255];
}
};
 
ClassicalNoise.prototype.dot = function(g, x, y, z) {
return g[0]*x + g[1]*y + g[2]*z;
};
 
ClassicalNoise.prototype.mix = function(a, b, t) {
return (1.0-t)*a + t*b;
};
 
ClassicalNoise.prototype.fade = function(t) {
return t*t*t*(t*(t*6.0-15.0)+10.0);
};
 
// Classic Perlin noise, 3D version
ClassicalNoise.prototype.noise = function(x, y, z) {
// Find unit grid cell containing point
var X = Math.floor(x);
var Y = Math.floor(y);
var Z = Math.floor(z);
// Get relative xyz coordinates of point within that cell
x = x - X;
y = y - Y;
z = z - Z;
// Wrap the integer cells at 255 (smaller integer period can be introduced here)
X = X & 255;
Y = Y & 255;
Z = Z & 255;
// Calculate a set of eight hashed gradient indices
var gi000 = this.perm[X+this.perm[Y+this.perm[Z]]] % 12;
var gi001 = this.perm[X+this.perm[Y+this.perm[Z+1]]] % 12;
var gi010 = this.perm[X+this.perm[Y+1+this.perm[Z]]] % 12;
var gi011 = this.perm[X+this.perm[Y+1+this.perm[Z+1]]] % 12;
var gi100 = this.perm[X+1+this.perm[Y+this.perm[Z]]] % 12;
var gi101 = this.perm[X+1+this.perm[Y+this.perm[Z+1]]] % 12;
var gi110 = this.perm[X+1+this.perm[Y+1+this.perm[Z]]] % 12;
var gi111 = this.perm[X+1+this.perm[Y+1+this.perm[Z+1]]] % 12;
// The gradients of each corner are now:
// g000 = grad3[gi000];
// g001 = grad3[gi001];
// g010 = grad3[gi010];
// g011 = grad3[gi011];
// g100 = grad3[gi100];
// g101 = grad3[gi101];
// g110 = grad3[gi110];
// g111 = grad3[gi111];
// Calculate noise contributions from each of the eight corners
var n000= this.dot(this.grad3[gi000], x, y, z);
var n100= this.dot(this.grad3[gi100], x-1, y, z);
var n010= this.dot(this.grad3[gi010], x, y-1, z);
var n110= this.dot(this.grad3[gi110], x-1, y-1, z);
var n001= this.dot(this.grad3[gi001], x, y, z-1);
var n101= this.dot(this.grad3[gi101], x-1, y, z-1);
var n011= this.dot(this.grad3[gi011], x, y-1, z-1);
var n111= this.dot(this.grad3[gi111], x-1, y-1, z-1);
// Compute the fade curve value for each of x, y, z
var u = this.fade(x);
var v = this.fade(y);
var w = this.fade(z);
// Interpolate along x the contributions from each of the corners
var nx00 = this.mix(n000, n100, u);
var nx01 = this.mix(n001, n101, u);
var nx10 = this.mix(n010, n110, u);
var nx11 = this.mix(n011, n111, u);
// Interpolate the four results along y
var nxy0 = this.mix(nx00, nx10, v);
var nxy1 = this.mix(nx01, nx11, v);
// Interpolate the two last results along z
var nxyz = this.mix(nxy0, nxy1, w);
 
return nxyz;
};
perlin-noise-simplex.js
JavaScript
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// Ported from Stefan Gustavson's java implementation
// http://staffwww.itn.liu.se/~stegu/simplexnoise/simplexnoise.pdf
// Read Stefan's excellent paper for details on how this code works.
//
// Sean McCullough banksean@gmail.com
 
/**
* You can pass in a random number generator object if you like.
* It is assumed to have a random() method.
*/
var SimplexNoise = function(r) {
if (r == undefined) r = Math;
this.grad3 = [[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]];
this.p = [];
for (var i=0; i<256; i++) {
this.p[i] = Math.floor(r.random()*256);
}
// To remove the need for index wrapping, double the permutation table length
this.perm = [];
for(var i=0; i<512; i++) {
this.perm[i]=this.p[i & 255];
}
 
// A lookup table to traverse the simplex around a given point in 4D.
// Details can be found where this table is used, in the 4D noise method.
this.simplex = [
[0,1,2,3],[0,1,3,2],[0,0,0,0],[0,2,3,1],[0,0,0,0],[0,0,0,0],[0,0,0,0],[1,2,3,0],
[0,2,1,3],[0,0,0,0],[0,3,1,2],[0,3,2,1],[0,0,0,0],[0,0,0,0],[0,0,0,0],[1,3,2,0],
[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],
[1,2,0,3],[0,0,0,0],[1,3,0,2],[0,0,0,0],[0,0,0,0],[0,0,0,0],[2,3,0,1],[2,3,1,0],
[1,0,2,3],[1,0,3,2],[0,0,0,0],[0,0,0,0],[0,0,0,0],[2,0,3,1],[0,0,0,0],[2,1,3,0],
[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],
[2,0,1,3],[0,0,0,0],[0,0,0,0],[0,0,0,0],[3,0,1,2],[3,0,2,1],[0,0,0,0],[3,1,2,0],
[2,1,0,3],[0,0,0,0],[0,0,0,0],[0,0,0,0],[3,1,0,2],[0,0,0,0],[3,2,0,1],[3,2,1,0]];
};
 
SimplexNoise.prototype.dot = function(g, x, y) {
return g[0]*x + g[1]*y;
};
 
SimplexNoise.prototype.noise = function(xin, yin) {
var n0, n1, n2; // Noise contributions from the three corners
// Skew the input space to determine which simplex cell we're in
var F2 = 0.5*(Math.sqrt(3.0)-1.0);
var s = (xin+yin)*F2; // Hairy factor for 2D
var i = Math.floor(xin+s);
var j = Math.floor(yin+s);
var G2 = (3.0-Math.sqrt(3.0))/6.0;
var t = (i+j)*G2;
var X0 = i-t; // Unskew the cell origin back to (x,y) space
var Y0 = j-t;
var x0 = xin-X0; // The x,y distances from the cell origin
var y0 = yin-Y0;
// For the 2D case, the simplex shape is an equilateral triangle.
// Determine which simplex we are in.
var i1, j1; // Offsets for second (middle) corner of simplex in (i,j) coords
if(x0>y0) {i1=1; j1=0;} // lower triangle, XY order: (0,0)->(1,0)->(1,1)
else {i1=0; j1=1;} // upper triangle, YX order: (0,0)->(0,1)->(1,1)
// A step of (1,0) in (i,j) means a step of (1-c,-c) in (x,y), and
// a step of (0,1) in (i,j) means a step of (-c,1-c) in (x,y), where
// c = (3-sqrt(3))/6
var x1 = x0 - i1 + G2; // Offsets for middle corner in (x,y) unskewed coords
var y1 = y0 - j1 + G2;
var x2 = x0 - 1.0 + 2.0 * G2; // Offsets for last corner in (x,y) unskewed coords
var y2 = y0 - 1.0 + 2.0 * G2;
// Work out the hashed gradient indices of the three simplex corners
var ii = i & 255;
var jj = j & 255;
var gi0 = this.perm[ii+this.perm[jj]] % 12;
var gi1 = this.perm[ii+i1+this.perm[jj+j1]] % 12;
var gi2 = this.perm[ii+1+this.perm[jj+1]] % 12;
// Calculate the contribution from the three corners
var t0 = 0.5 - x0*x0-y0*y0;
if(t0<0) n0 = 0.0;
else {
t0 *= t0;
n0 = t0 * t0 * this.dot(this.grad3[gi0], x0, y0); // (x,y) of grad3 used for 2D gradient
}
var t1 = 0.5 - x1*x1-y1*y1;
if(t1<0) n1 = 0.0;
else {
t1 *= t1;
n1 = t1 * t1 * this.dot(this.grad3[gi1], x1, y1);
}
var t2 = 0.5 - x2*x2-y2*y2;
if(t2<0) n2 = 0.0;
else {
t2 *= t2;
n2 = t2 * t2 * this.dot(this.grad3[gi2], x2, y2);
}
// Add contributions from each corner to get the final noise value.
// The result is scaled to return values in the interval [-1,1].
return 70.0 * (n0 + n1 + n2);
};
 
// 3D simplex noise
SimplexNoise.prototype.noise3d = function(xin, yin, zin) {
var n0, n1, n2, n3; // Noise contributions from the four corners
// Skew the input space to determine which simplex cell we're in
var F3 = 1.0/3.0;
var s = (xin+yin+zin)*F3; // Very nice and simple skew factor for 3D
var i = Math.floor(xin+s);
var j = Math.floor(yin+s);
var k = Math.floor(zin+s);
var G3 = 1.0/6.0; // Very nice and simple unskew factor, too
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 = xin-X0; // The x,y,z distances from the cell origin
var y0 = yin-Y0;
var z0 = zin-Z0;
// For the 3D case, the simplex shape is a slightly irregular tetrahedron.
// Determine 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=1; j1=0; k1=0; i2=1; j2=1; k2=0; } // X Y Z order
else if(x0>=z0) { i1=1; j1=0; k1=0; i2=1; j2=0; k2=1; } // X Z Y order
else { i1=0; j1=0; k1=1; i2=1; j2=0; k2=1; } // Z X Y order
}
else { // x0<y0
if(y0<z0) { i1=0; j1=0; k1=1; i2=0; j2=1; k2=1; } // Z Y X order
else if(x0<z0) { i1=0; j1=1; k1=0; i2=0; j2=1; k2=1; } // Y Z X order
else { i1=0; j1=1; k1=0; i2=1; j2=1; k2=0; } // Y X Z order
}
// A step of (1,0,0) in (i,j,k) means a step of (1-c,-c,-c) in (x,y,z),
// a step of (0,1,0) in (i,j,k) means a step of (-c,1-c,-c) in (x,y,z), and
// a step of (0,0,1) in (i,j,k) means a step of (-c,-c,1-c) in (x,y,z), where
// c = 1/6.
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 gi0 = this.perm[ii+this.perm[jj+this.perm[kk]]] % 12;
var gi1 = this.perm[ii+i1+this.perm[jj+j1+this.perm[kk+k1]]] % 12;
var gi2 = this.perm[ii+i2+this.perm[jj+j2+this.perm[kk+k2]]] % 12;
var gi3 = this.perm[ii+1+this.perm[jj+1+this.perm[kk+1]]] % 12;
// Calculate the contribution from the four corners
var t0 = 0.6 - x0*x0 - y0*y0 - z0*z0;
if(t0<0) n0 = 0.0;
else {
t0 *= t0;
n0 = t0 * t0 * this.dot(this.grad3[gi0], x0, y0, z0);
}
var t1 = 0.6 - x1*x1 - y1*y1 - z1*z1;
if(t1<0) n1 = 0.0;
else {
t1 *= t1;
n1 = t1 * t1 * this.dot(this.grad3[gi1], x1, y1, z1);
}
var t2 = 0.6 - x2*x2 - y2*y2 - z2*z2;
if(t2<0) n2 = 0.0;
else {
t2 *= t2;
n2 = t2 * t2 * this.dot(this.grad3[gi2], x2, y2, z2);
}
var t3 = 0.6 - x3*x3 - y3*y3 - z3*z3;
if(t3<0) n3 = 0.0;
else {
t3 *= t3;
n3 = t3 * t3 * this.dot(this.grad3[gi3], x3, y3, z3);
}
// Add contributions from each corner to get the final noise value.
// The result is scaled to stay just inside [-1,1]
return 32.0*(n0 + n1 + n2 + n3);
};

Thanks for sharing! I found the Classical function to be noticeably faster than the Simplex3D while polling large numbers of points. (Chrome 28.0.1500.95)

yes, thanks for this. I'm using it to generate random numbers to drive a drunk walk function I wrote in javascript for max for live (max/msp in ableton live): https://github.com/blakelymcconnell/m4l_js2liveAPI

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