Fabian Sanglard's exploration[1] of Doom3 is much more in depth than this article, though the author does quote Sanglard's analysis albeit with a small source link
The vanilla code review goes into the app structure first, and (what little I've read of) the BFG review compares that codebase against the vanilla one.
http://fabiensanglard.net/doom3/index.php
The vanilla code review goes into the app structure first, and (what little I've read of) the BFG review compares that codebase against the vanilla one.