PImage sourceimg, lastimg, refimg, dummy, dummyblobs;
int imgcounter = 0;

String url = "http://images.earthcam.com/ec_metros/newyork/newyork/fridays.jpg";

int avg_source, avg_ref, frame;

void setup()
{
  size(640, 240);
  frameRate(2);
  
  sourceimg = loadImage(url);
  
  lastimg = sourceimg;
  refimg = sourceimg;
  dummyblobs = new PImage(sourceimg.width/4, sourceimg.height/4, RGB);

  dummy = new PImage(sourceimg.width, sourceimg.height, ARGB);
  refimg = new PImage(sourceimg.width, sourceimg.height, RGB);
}

void draw()
{
  background(255);
  sourceimg = loadImage(url);
  image(sourceimg, 0, 0, width/2, height);
  image(refimg, width/2, 0, width/2, height);
  
  drawDiff();
  //image(dummy, 0, 0, width, height);
  
  sourceimg.loadPixels();
  lastimg.loadPixels();
  
  arraycopy(sourceimg.pixels, lastimg.pixels);
  
  lastimg.updatePixels();
  
  frame ++;
}

void keyPressed()
{
  //sourceimg.save("/home/zoellner/killswitch_source_"+frame+".jpg");
  //refimg.save("/home/zoellner/killswitch_ref_"+frame+".jpg");
  saveFrame("superplonk_####");
}

void drawDiff()
{
  int avg = 0;
  for (int i=0; i<sourceimg.pixels.length; i++)
  {
    avg += brightness(sourceimg.pixels[i]);
  }
  
  avg_source = avg / sourceimg.pixels.length;
  println("avg "+avg_source);
  
  int correction = (avg_ref < avg_source) ? avg_source - avg_ref : avg_ref - avg_source;
  
  dummy.loadPixels();
  refimg.loadPixels();
  for (int i=0; i<sourceimg.pixels.length; i++)
  {
    int treshold = 10;
    
    float lastpixel = brightness(lastimg.pixels[i]);
    float thispixel = brightness(sourceimg.pixels[i]);
    
    float thisresult = (lastpixel > thispixel) ? lastpixel - thispixel : thispixel - lastpixel;
    
    // intensity normalization
     thisresult -= (thisresult < correction) ? thisresult : correction;
    
     if (thisresult < treshold)
     {
       refimg.pixels[i] = color( (brightness(refimg.pixels[i]) + brightness(sourceimg.pixels[i])) / 2);
     }
     
     float refpixel = brightness(refimg.pixels[i]);
     float refresult = (refpixel > thispixel) ? refpixel - thispixel : thispixel - refpixel;
     
     if (refresult > treshold)
     {
        dummy.pixels[i] = color(0,255,0,150);
     }
     else
     {
       dummy.pixels[i] = color(0,0,0,0);
     }
       
     dummy.updatePixels();
     refimg.updatePixels();
     
     avg_ref = avg_source;
  }
}