# Re: Smooth random?

Hello. It seems that 1-dimensional Perlin Noise is suitable for Smooth Random needed.
Here is implementation of it using “js”.
It's based on http://asserttrue.blogspot.com/2011/12/perlin-noise-in-javascript_31.html

———————
//—————————————————-
// Perlin Noise implementation for Max/MSP javascript.
// by Denis Perevalov
//—————————————————-
// Based on Kas Thomas code:
// http://asserttrue.blogspot.com/2011/12/perlin-noise-in-javascript_31.html
// This is a port of Ken Perlin's Java code. The
// original Java code is at http://cs.nyu.edu/%7Eperlin/noise/.
// Note that in this version, a number from 0 to 1 is returned.
//—————————————————-

//Usage:
//send to first inlet input – x.
//then ferst outlet returns perlin(x).

// inlets and outlets
inlets = 1; //x, for 1-dim perlin noise
outlets = 1; //output = perlin(x)

// global variables

var p = new Array(512);
var 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
];
var _inited = false;

//——————————————-
// float — run the equation once
function msg_float(x)
{
var out = perlin( x, Math.sin(x), Math.cos(x) );
//post(out);
outlet(0, out);
}

//——————————————-
function init()
{
post(“Perlin inited”);
for (var i=0; i < 256 ; i++) {
p[256+i] = p[i] = permutation[i];
}

}

//——————————————-
function perlin( x, y, z ) {
if ( !_inited ) {
_inited = true;
init();
}

var X = Math.floor(x) & 255, // FIND UNIT CUBE THAT
Y = Math.floor(y) & 255, // CONTAINS POINT.
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);
v = fade(y), // FOR EACH OF X,Y,Z.
var A = p[X ]+Y, AA = p[A]+Z, AB = p[A+1]+Z, // HASH COORDINATES OF
B = p[X+1]+Y, BA = p[B]+Z, BB = p[B+1]+Z; // THE 8 CUBE CORNERS,

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

//——————————————-
function fade(t) { return t * t * t * (t * (t * 6 – 15) + 10); }
function lerp( t, a, b) { return a + t * (b – a); }
function grad(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.
v = h<4 ? y : h==12||h==14 ? x : z;
return ((h&1) == 0 ? u : -u) + ((h&2) == 0 ? v : -v);
}
function scale(n) { return (1 + n)/2; }

//——————————————-

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###### Attachments:
Sep 15, 2012 at 1:04pm #82341