Robert describes his XreaL renderer as being almost like that in Doom 3 and has already implemented numerous advance features like a light interaction system and shadow mapping. The traditional id Tech 3 (and ioquake3) engine is rather CPU bottlenecked on today's hardware, but Robert has addressed that too. He has worked to remove all CPU bottlenecks and pushed all of the rendering to being VBO-based on the GPU. This work has led to tremendous performance improvements. There are also many similarities between the design of this engine and what can be found in Doom 3 and Call of Duty 4, while being more powerful than the open-source DarkPlaces-based Nexuiz and Sauerbraten game engines.
Beyond offering wonderful graphics capabilities, the XreaL engine is also able to load game content from Quake 3, Doom 3, Unreal Tournament 2004, and even Unreal Tournament 3! There is not even an Unreal Tournament 3 client for Linux yet, but this open-source engine can read the game’s content.
While XreaL can utilize content from other games and offer so many advanced features, its own game content is not the best. The key XreaL developers are all programmers and not artists, and unfortunately, they just lost one of their main artists so they are in need of help to make XreaL appealing as an actual game too. XreaL is developed 100% using open-source software while tools like Maya and 3D Studio Max are avoided. To handle some of the needs, Robert is working on writing new tools for Blender3D tools to import and export Unreal-based characters and in fact an entire game SDK such as its own map compiler and level editor.
More information on XreaL is available from its project web-site. Those interested in trying out XreaL will need to checkout the code from their SourceForge SVN repository and build it from source. Fortunately, they will be approaching a new release shortly or at least providing an easy to obtain development snapshot. At that time we will also incorporate the XreaL engine into the Phoronix Test Suite. Robert Beckebans also shared that other ioquake3-based games may end up switching to the XreaL engine for its advantages. The game content is not the best in XreaL right now, but this engine appears to be quite powerful and is continuing to grow. You can be sure that we will cover more of XreaL on Phoronix in the near future as it develops.