ippa/jaws — pull request #39 by Johnicholas (2012-02-07 17:32:30+00:00)
Title: tilemap bug and fix?

I think this demonstrates a bug (with a unit test) and then fixes it.

The tilemap was hitting undefined cells and aborting,
which made my map vanish when the player was near the bottom of the world.

I don't think these checks have any significant performance hit
(and pulling the parseInt out of the loop might even be faster?).