To make the opensource project even better! :P

The compiler has optimized the rendering engine too much to be decompiled into any useable code. Somebody is working on Linux and 64bit support which will need to have this completely rewritten. https://github.com/dkfans/keeperfx/blob/master/src/bflib_render_gpoly.c

The maintainer of KeeperFX told me that EA does not have the original code anymore though.