impression of boiling lava. It's a very neat effect if I may say so. I've got some more ideas along that scale but those will require new tiles (or rather tweaked existing ones) that'll make old saves look wonky, something I'm trying to avoid until we've got a halfway playable official tiles version out there. Has the side effect of visualizing how often the tiles buffer gets updated, apparently not remotely as often as I thought, but rather with every viewwindow which seems reasonable.

git-svn-id: https://crawl-ref.svn.sourceforge.net/svnroot/crawl-ref/trunk@10032 c06c8d41-db1a-0410-9941-cceddc491573