[kenferry]

If you play the game, it's actually quite trivial to program deterministically. :-) Flapping is not implemented as an impulse. It's more like jumping in Mario - it instantaneously fires a canned "flap" movement that is always the same.

Set flap_height = bottom of next pipe + constant.

If bird height < flap_height, flap.

Done!

[userbinator]

It also looks like you'd want to avoid flapping into the top of the pipe.

[kenferry]

Perhaps I should have said "threshold_height".

    threshold_height = bottom_of_pipe_height + 10 pixels; // or something

    if (current_height < threshold_height)
      flap
    else
      don't flap

If you never flap when above the threshold, you will not hit the top.