You have to choose. Either you want something exactly like that and you port the downloadable source code on the linked page to working Processing code. Or you want something simple and you try easier methods to create the same effect - rather than the exact same result - in Processing. For example using noise().

Code Example

1. PImage pg;
2. float xf, yf, fc, factor = 0.0025;
3.  
4. void setup() {
5.   size(1280, 720);
6.   pg = createImage(width/4, height/4, RGB);
7.   colorMode(HSB, 1);
8. }
9.  
10. void draw() {
11.   fc = frameCount*0.003;
12.   pg.loadPixels();
13.   for (int y=0; y<pg.height; y++) {
14.     for (int x=0; x<pg.width; x++) {
15.       xf = x*factor;
16.       yf = y*factor;
17.       pg.pixels[x+y*pg.width] = color(noise(xf+fc, yf+fc, fc), noise(yf, xf), 1);
18.     }
19.   }
20.   pg.updatePixels();
21.   image(pg, 0, 0, width, height);
22. }