This uses the RBDoom3-BFG engine, so get that.
http://www.moddb.com/mods/doom-3-bfg-ultimate/downloads
Extract the "@UltimateHD" folder and place it next to your "base" folder.
Use: "rbdoom3bfg +set fs_resourceLoadPriority 0 +set fs_game @UltimateHD +set r_lightscale 1 +set r_overbright 1" to launch the game. This should lower the brightness which can also be adjusted in game settings menu. Set the fov in game settings menu, at 1920x1080 an fov of 100 works well. Soft shadows and AA can also be set.