HaxePunk/HaxePunk — pull request #129 by fserb (2013-07-19 14:41:59+00:00)
Title: include proper number of tiles do draw on Tilemap

So, the Math.floor(-x) is better than -Math.floor(x) or -Math.ceil(x), since it always do the right thing, i.e., include the previous tile.

This means that we should always be drawing width/tw + 1 tile, which before was included in the bug.