// Sketch for generating sticky atoms
// (c) 2006 duane a. bailey

final static int SIZE = 300;
int points;
int closePoints;
BFont ArialBold;
int side, dist, oldx, oldy;
float angle, dx, dy, x, y;

void begin()
{
  side = int(random(4));
  dist = int(random(SIZE));
  angle = random(2*3.1415926);
  dx = cos(angle);
  dy = sin(angle);
  x = 0; y = 0;
  switch (side)
  {
    case 0:
      x = 0; y = dist; break;
    case 1:
      x = dist; y = 0; break;
    case 2:
      x = SIZE-1; y = dist; break;
    case 3:
      x = dist; y = SIZE-1; break;
  }
}
color b,r,w;
int xq[],yq[];
int QLEN=100;
int nq,qh,qt;
void setup()
{
   b = color (0,0,0);
   r = color (255,0,0);
   w = color(255,255,255);
  size(SIZE,SIZE);
  xq = new int[QLEN];
  yq = new int[QLEN];
  nq = 0;
  qh = 0;
  qt = 0;
  background(255);
  //fill(r); noStroke();
  //ellipseMode(CORNER);
  //ellipse(SIZE/2-10,SIZE/2-10,20,20);
  //set(SIZE/2,SIZE/2,r);
  set(SIZE/2,SIZE/2,r);
  begin();
}

void add(int x, int y)
{
  if (nq < QLEN) {
    nq++;
  } else {
    set(xq[qh],yq[qh],w);
    qh = (qh+1)%QLEN;
  }
  set(x,y,b);
  xq[qt] = x;
  yq[qt] = y;
  qt = (qt+1)%QLEN;
}

boolean near(int ix, int iy)
{
  if (ix > 0) {
    if (iy > 0 && r == get(ix-1,iy-1)) return true;
    if (r == get(ix-1,iy)) return true;
    if (iy < SIZE-1 && r == get(ix-1,iy+1)) return true;
  }
  if (iy > 0 && r == get(ix,iy-1)) return true;
  if (iy < SIZE-1 && r == get(ix,iy+1)) return true;
  if (ix < SIZE-1) {
    if (iy > 0 && r == get(ix+1,iy-1)) return true;
    if (r == get(ix+1,iy)) return true;
    if (iy < SIZE-1 && r == get(ix+1,iy+1)) return true;
  }
  return false;
}

void loop()
{
  for (int i = 0; i < 200; i++) {
  if (x >= 0 && x < SIZE && y >= 0 && y < SIZE) {
    x = x + dx;
    y = y + dy;
    int ix = int(x);
    int iy = int(y);
    if (near(ix,iy)) {
      set(ix,iy,r);
      begin();
    } else {
      add(ix,iy);
    }
  } else begin();
  }
}