/*
Robot Etching Acid number 6
Paver or River
*/
paving [] p;
int w,h,count;
BImage swap,map;
int drawit = 1;
void setup(){
  count = 0;
  swap = loadImage("b.gif");
  map = swap.copy();
  for(int i = 0; i < map.pixels.length; i++){
    map.pixels[i] = #000000;
  }
  w = swap.width;
  h = swap.height;
  size(600,442);//applet
  //size(w*2,h);//non applet with bot collision map
  //size(w,h);//print mode
  println("Canvas size: width:"+w+" height:"+h);
  p = new paving[2000];
  for (int i = 0; i < p.length/2; i++){
    int rw = int(random(w));
    int rh = int(random(h));
    p[i] = new paving(rw,rh,true);
  }
  for (int i = p.length/2; i < p.length; i++){
    int rw = int(random(w));
    int rh = int(random(h));
    p[i] = new paving(rw,rh,false);
  }
}
void loop(){
  image(swap,0,0);
  //image(map,w,0);//bot collision map
  for (int i = 0; i < p.length; i++){
    p[i].pave();
    p[i].check();
    p[i].move();
    if(drawit == 0){
      p[i].draw();//reminder this line to not draw paver sprites
    }
  }
}

void mousePressed(){
  save("pavers.tif");
  println("save count "+count++);
}
void keyPressed(){
  drawit++;
  drawit %= 2;
}
class paving{
  int x,y,d,thresh,step;
  boolean male;
  paving(int x, int y, boolean male){
    this.x = x;
    this.y = y;
    this.thresh = grey(swap.pixels[x + y * w]);
    this.male = male;
    d = 0;
    step = 10;
    if (male){
      step = -10;
    }
    map.pixels[x + y * w] = #00FF00;
  }
  void draw(){
    color c = swap.pixels[x + y * w];
    noStroke();
    fill(c);
    ellipse(x-2,y-2,5,5);
  }
  void move(){
    map.pixels[x + y * w] = #000000;
    switch(d){
      case 0:
      x = (x+1)%w; break;
      case 1:
      y = (y+1)%h; break;
      case 2:
      x = wr(x-1,w-1); break;
      case 3:
      y = wr(y-1,h-1); break;
    }
    map.pixels[x + y * w] = #00FF00;
  }
  void check(){
    d = 5;
    if (male){
      if (grey(swap.pixels[((x+1)%w) + y * w]) <= thresh && map.pixels[((x+1)%w) + y * w] == #000000){
        d = 0;
      } else if (grey(swap.pixels[x + ((y+1)%h) * w]) <= thresh && map.pixels[x + ((y+1)%h) * w] == #000000){
        d = 1;
      } else if (grey(swap.pixels[wr(x-1,w-1) + y * w]) <= thresh && map.pixels[wr(x-1,w-1) + y * w] == #000000){
        d = 2;
      } else if (grey(swap.pixels[x + wr(y-1,h-1) * w]) <= thresh && map.pixels[x + wr(y-1,h-1) * w] == #000000){
        d = 3;
      }
    } else {
      if (grey(swap.pixels[((x+1)%w) + y * w]) >= thresh && map.pixels[((x+1)%w) + y * w] == #000000){
        d = 0;
      } else if (grey(swap.pixels[x + ((y+1)%h) * w]) >= thresh && map.pixels[x + ((y+1)%h) * w] == #000000){
        d = 1;
      } else if (grey(swap.pixels[wr(x-1,w-1) + y * w]) >= thresh && map.pixels[wr(x-1,w-1) + y * w] == #000000){
        d = 2;
      } else if (grey(swap.pixels[x + wr(y-1,h-1) * w]) >= thresh && map.pixels[x + wr(y-1,h-1) * w] == #000000){
        d = 3;
      }
    }
  }
  void pave(){
    int [] opt = new int[4];
    d = 5;
    //calculate threshold deltas
    if(male){
      opt[0] = grey(swap.pixels[((x+1)%w) + y * w]) - thresh;
      opt[1] = grey(swap.pixels[x + ((y+1)%h) * w]) - thresh;
      opt[2] = grey(swap.pixels[wr(x-1,w-1) + y * w]) - thresh;
      opt[3] = grey(swap.pixels[x + wr(y-1,h-1) * w]) - thresh;
    }else{
      opt[0] = thresh - grey(swap.pixels[((x+1)%w) + y * w]);
      opt[1] = thresh - grey(swap.pixels[x + ((y+1)%h) * w]);
      opt[2] = thresh - grey(swap.pixels[wr(x-1,w-1) + y * w]);
      opt[3] = thresh - grey(swap.pixels[x + wr(y-1,h-1) * w]);
    }
    int val = 255;
    for (int i = 0; i < opt.length; i++){
      if (opt[i] < val && opt[i] > 0){
        d = i; val = opt[i];
      }
    }
    switch(d){
      case 0:
      swap.pixels[((x+1)%w) + y * w] = tone(swap.pixels[((x+1)%w) + y * w],step); break;
      case 1:
      swap.pixels[x + ((y+1)%h) * w] = tone(swap.pixels[x + ((y+1)%h) * w],step); break;
      case 2:
      swap.pixels[wr(x-1,w-1) + y * w] = tone(swap.pixels[wr(x-1,w-1) + y * w],step); break;
      case 3:
      swap.pixels[x + wr(y-1,h-1) * w] = tone(swap.pixels[x + wr(y-1,h-1) * w],step); break;
    }
  }
}
//screen wrap around function
int wr(int v, int lim){
  if (v < 0){
    v = lim;
  }
  return v;
}
color tone (color c, int val){
  int r=c>>16&0xff;
  int g=c>>8&0xff;
  int b=c&0xff;
  r += val;
  g += val;
  b += val;
  return color(r,g,b);
}
int grey(color p){
  int  r=p>>16&0xff;
  int  g=p>>8&0xff;
  int  b=p&0xff;
  return (r+g+b)/3;
}