// Cellular Automata 2 
// by Mike Davis <http://www.lightcycle.org> 

 
World w; 
int numcells = 0; 
int maxcells = 4700; 
Cell[] cells = new Cell[maxcells]; 
color spore_color; 
// set lower for smoother animation, higher for faster simulation 
int runs_per_loop = 10000; 
color black = color(0, 0, 0); 
  
void setup() 
{ 
  size(200, 200); 
  framerate(24); 
  clearscr();  
  w = new World(); 
  spore_color = color(172, 255, 128); 
  seed(); 
} 
 
void seed() 
{ 
  // Add cells at random places 
  for (int i = 0; i < maxcells; i++) 
  { 
    int cX = (int)random(width); 
    int cY = (int)random(height); 
    if (w.getpix(cX, cY) == black) 
    { 
      w.setpix(cX, cY, spore_color); 
      cells[numcells] = new Cell(cX, cY); 
      numcells++; 
    } 
  } 
} 
 
void draw() 
{ 
  // Run cells in random order 
  for (int i = 0; i < runs_per_loop; i++) { 
    int selected = min((int)random(numcells), numcells - 1); 
    cells[selected].run(); 
  } 
} 
 
void clearscr() 
{ 
  for (int y = 0; y < height; y++) { 
    for (int x = 0; x < width; x++) { 
      set(x, y, color(0)); 
    } 
  } 
} 
 
class Cell 
{ 
  int x, y; 
  Cell(int xin, int yin) 
  { 
    x = xin; 
    y = yin; 
  } 
 
    // Perform action based on surroundings 
  void run() 
  { 
    // Fix cell coordinates 
    while(x < 0) { 
      x+=width; 
    } 
    while(x > width - 1) { 
      x-=width; 
    } 
    while(y < 0) { 
      y+=height; 
    } 
    while(y > height - 1) { 
      y-=height; 
    } 
    
    // Cell instructions 
    if (w.getpix(x + 1, y) == black) { 
      move(0, 1); 
    } else if (w.getpix(x, y - 1) != black && w.getpix(x, y + 1) != black) { 
      move((int)random(9) - 4, (int)random(9) - 4); 
    } 
  } 
  
  // Will move the cell (dx, dy) units if that space is empty 
  void move(int dx, int dy) { 
    if (w.getpix(x + dx, y + dy) == black) { 
      w.setpix(x + dx, y + dy, w.getpix(x, y)); 
      w.setpix(x, y, color(0)); 
      x += dx; 
      y += dy; 
    } 
  } 
} 
 
//  The World class simply provides two functions, get and set, which access the 
//  display in the same way as getPixel and setPixel.  The only difference is that 
//  the World class's get and set do screen wraparound ("toroidal coordinates"). 
class World 
{ 
  void setpix(int x, int y, int c) { 
    while(x < 0) x+=width; 
    while(x > width - 1) x-=width; 
    while(y < 0) y+=height; 
    while(y > height - 1) y-=height; 
    set(x, y, c); 
  } 
  
  color getpix(int x, int y) { 
    while(x < 0) x+=width; 
    while(x > width - 1) x-=width; 
    while(y < 0) y+=height; 
    while(y > height - 1) y-=height; 
    return get(x, y); 
  } 
} 
 
void mousePressed() 
{ 
  setup(); 
}