https://bugs.winehq.org/show_bug.cgi?id=43896
--- Comment #10 from mx2 mxm2@hotmail.de --- Those "white walls" are caused by some broken exterior shader, most likely water. If I load a saved game inside some building there are no "white walls" until I go outside.
It also noticeable that the "white wall" issue slows the game down and gets worse over time until the screen gets completely messed up (see attachment "Screenshot, messed up").