var pipe_pair = function(x)
{
  var gap = 100;
  var y = Math.random_range(0,200) - gap;
  world.spawn(ur.pipe).pos = [x,y];
  var pipe2 = world.spawn(ur.pipe);
  pipe2.scale = [1,-1];
  pipe2.pos = [x,y+gap];
  var wall = world.spawn(ur.scorewall);
  wall.pos = [x+30,y+gap/2];
  wall.edge2d.sensor = true;
}

var gndx = -1000;
var lastpipe = Game.camera.right() - 100;

this.start = function()
{
  pipe_pair(lastpipe);
}

this.update = function()
{
  while (gndx < Game.camera.right()) {
    var g = world.spawn(ur.ground);
    g.pos = [gndx,-200];
    gndx += g.width()-3;
  }

  if (Game.camera.pos.x > lastpipe-200) {
    lastpipe += 200;
    pipe_pair(lastpipe);
  }
}