Apparently, S.T.A.L.K.E.R.:Shadow of Chernobyl, which was released earlier this week, may contain game assets from both Half-Life 2 or Doom 3. When examining the folders from the game, one will find filenames that are remarkably — THE SAME — as those found in id’s and Valve’s software. These similarities have been found in lighting, as well as water textures.
It will be interesting to see how this situation plays out, as id’s Todd Hollenshead has already been quoted as calling the issue "concerning." GamerNode will have more on this story as it develops.