/* built with Studio Sketchpad: 
 *   https://sketchpad.cc
 * 
 * observe the evolution of this sketch: 
 *   https://studio.sketchpad.cc/sp/pad/view/ro.oDgArMDdyoD/rev.480
 * 
 * authors: 
 *   frederic.vernier

 * license (unless otherwise specified): 
 *   creative commons attribution-share alike 3.0 license.
 *   https://creativecommons.org/licenses/by-sa/3.0/ 
 */ 



PImage bg;
int t =0;
void setup() {  // this is run once.   
    
    // canvas size (Variable aren't evaluated. Integers only, please.)
    size(512, 512); 
    
    // limit the number of frames per second
    frameRate(2);
    
    bg = createImage(width, height, RGB);
} 
 
void draw() {
  // set the background color
  background(128);  t++;  
  
  int[] freqs = new int[1024];  

  for (int i=0; i<256; i++)
    freqs[i]=10;
  
  for(int j=0; j< bg.height/2; j++) {
      for(int i=0; i< bg.width/2; i++) {
        int c = int(random(0, 255));
        freqs[c]++;
        bg.pixels[i+j*width] = color(c, c, c); 
        
        c = int(256*noise(i/64, j/64, t));
        freqs[c+256]++;
        bg.pixels[i+256+j*width] = color(c, c, c); 
        
        c = 255-int(sqrt(sqrt(random(0, 256*256*256*256-1))));
        freqs[c+256+256]++;
        bg.pixels[i+(j+256)*width] = color(c, c, c); 
      
        c = int(sqrt(sqrt(random(0, 255)*random(0, 255)*random(0, 255)*random(0,255))));
        freqs[c+256+256+256]++;
        bg.pixels[i+256+(j+256)*width] = color(c, c, c); 
      }
    }
    image(bg, 0 ,0);
    stroke(0, 255, 0);
    for (int i=0; i<256; i++) {
      line(i, height/2-freqs[i]/10, i, height/2);
      line(i+256, height/2-freqs[i+256]/10, i+256, height/2);
      line(i, height-freqs[i+256+256]/10, i, height);
      line(i+256, height-freqs[i+256+256+256]/10, i+256, height);
    }
}