At the QuakeCon 2007, John Carmack, the lead graphics engine developer at id, said to LinuxGames: “I mean, I won’t commit to a date, but the Doom 3 stuff will be open source”. And like its predecessors, John Carmack has said that id Tech 4 will be released as open source. On November 22, 2011, Carmack released the Doom 3 source code on Github. On October 19, 2012 Carmack announced on Twitter “Got approval for GPL release of Doom 3 BFG code (minus third party bits)!”.
It seems most of the work is already done. Hope we see it in 2012.
The BFG Edition features enhanced graphics, better sound with more horror effects, a checkpoint save system, and support for 3D displays and HMDs. The game also includes the previous expansion Resurrection of Evil and a new single player expansion pack called The Lost Mission. Additionally, it includes copies of the original Doom (“The Ultimate Doom” edition with add-on fourth episode, Thy Flesh Consumed), and Doom 2 with the new episode “No Rest For The Living”, previously available for Xbox 360. The BFG Edition also features the ability to use the flashlight while holding a weapon, in the form of the so-called armor-mounted flashlight.