As was reported earlier this week, id Software has open-sourced Wolfenstein: Enemy Territory and Return To Castle Wolfenstein. Opening up these older games under the GNU GPL was done as part of id's long-standing tradition of putting out the code into the public domain once it makes sense for them a few years after their succeeding engine updates have fully replaced them in the marketplace. The developers behind ioquake3, the project that's based around the Quake 3 engine that was previously opened up by id Software, is already working on iowolfet and iortcw forks to incorporate this new code, but other free software developers are already utilizing this code too.
Besides ioquake3 already working to utilize the fresh Enemy Territory and Return To Castle Wolfenstein code, the main developer behind XreaL is also utilizing this code in his open-source project and is in fact switching away from the vanilla Quake 3 engine to using the Wolfenstein: Enemy Territory engine. The engine used by Enemy Territory is based upon the Return To Castle Wolfenstein code, which in turn was derived from the original Quake 3 engine source-code. While still based upon the id Tech 3 technology, the Enemy Territory engine offers up new skeletal animation, foliage, and decal rendering code along with numerous improvements to game-play functions.
In regards to the XreaL project, we exclusively reported on the work back in April 2009 as perhaps the most advanced open-source engine. Back then the XreaL engine sported a pure GLSL renderer written against the OpenGL ES 2.0 specification, a true 64-bit HDR rendering pipeline, OpenGL 3.x support, VBO-based rendering, and other advanced visual features. XreaL also possessed the ability to load game content from Unreal Tournament 2004, Doom 3, and Unreal Tournament 3.
Over the past year, XreaL has since fallen off the radar again and has received some little work; there still is no official release. In fact, XreaL from the game perspective is dead. Rather than producing an entire game, the developer is now focusing upon just making XreaL be an advanced open-source game engine and leave it up to other game projects to create all of the artwork and content while leveraging the XreaL engine instead of, for example, the ioquake3 engine.
An ET-XreaL branch is now being made and it's going to offer the new Enemy Territory source-code, but the renderer will be replaced by the XreaL renderer. According to this announcement, XreaL with the ET engine will be targeted at Enemy Territory mod developers and those wishing to create their own standalone games based off of this id Software title.
Another new feature to XreaL is the renderer now supports parallel-split shadow maps, which is demonstrated below.