http://bugs.winehq.org/show_bug.cgi?id=11819
--- Comment #38 from Octavian Voicu octavian.voicu@gmail.com 2011-11-10 13:25:57 CST --- (In reply to comment #37)
It decides what rectangles need to be cleared in the z-buffer by transforming the bounding box of characters using IDirect3DDevice2::TransformVertices()
There's a typo here, I meant IDirect3DViewport2::TransformVertices().