I've had somewhat similar problems arise before and I found it was due to having another program making use of opengl acceleration at the same time as the game, in my case photoshop. The symptoms didn't look exactly like this but somewhat close; the bug I encountered made the floors disappear and eventually had textures floating all over the screen until I couldn't see anything but a SK jackson pollock. Also, in my case it was fixed by restarting the game after closing photoshop.

Don't know how helpful this is but in the slim chance you might have installed something that runs in the background using your video card acceleration, you might want to try turning it off to see if it helps.