DOOM 3 BFG includes:
RBDOOM-3 adds Linux and Mac support as well as soft shadows.
Requires the Steam Release of Doom 3 BFG Edition
This tool comes with a build of RBDOOM3BFG for Windows and also a tool which extracts all the content of Doom 3 BFG so it is in a moddable structured directory, doing this will allow you to use basic Doom 3 (2004) mods consisting of replaced sounds and textures (mods with modified dll files will not work).
Unzip into your Doom 3 Bfg install directory, run RBDoom3bfg.exe and enjoy.
higher poly models, tga textures, and effects including soft shadows (RBDoom3bfg)
+set g_fov X