Link[] chain;

void setup() {
  size(400, 400, P2D);
  frameRate(100);
  //smooth();
  
  chain = new Link[40];
  Link prev_link = null;
  for(int i = 0; i < chain.length; i++) {
    chain[i] = new Link(prev_link, 0, i*Link.LINK_SEPARATION);
    prev_link = chain[i];
  }
  chain[0].mass = 9999999;
}

void draw() {
  chain[0].x = chain[0].px = mouseX;
  chain[0].y = chain[0].py = mouseY;
  for(int i = 0; i < chain.length; i++)
    chain[i].update(1.0/40);
  for(int i = 0; i < chain.length; i++)
    chain[i].relax();
  
  //background(255);
  noStroke();
  fill(0, 5);
  rect(0, 0, width, height);
  
  for(int i = 2; i < chain.length; i++)
    chain[i].draw();
}