implement stepwise execution

[after12am]

I wonder that using yeild make it possible to implement stepwise execution like this.

[after12am]

could not use 'yield' because chrome have not implemented it. canary and firefox does support. but umm...

So I correspond by adding one object at a time.

var n = 0;
function animate() {
  requestAnimationFrame( animate );

  // if rendering one object at a time
  renderer.build(prod.objects[n]);
  n++;

  renderer.render();
}