Dragora Framework is our own proprietary game engine (means, we don't give commercial or free licenses, for now), for our game "The OpenHeaven Project" exclusive for Linux, born because we are tired of the so-restrictive free version Unity3D, and don't want pay thouslands of dollars (our college payments is more important!), and UDK!, their UI of the editor is so complicated and get lost in 10 seconds.
The Dragora Framework is based in the OGRE3D (1.8.1-1.9) 3d rendering engine with own modifcations and features, also with Bullet Physics, cAudio 3D Audio System, eyecandy effects for enviroments and scenes, new animation system called "SmartBody" (i think it's the first game engine to integrate him), deployment and build tools, etc. But i think is the first game engine is completely developed in Linux.
We heavily work in the game editor, DragonArchitect, fully written in C++/Gtkmm, instead of Qt that many companies and developers use for this purpose, we chosen GTK+ due their lightweight. an disadvantage is many deprecation of components and hard to port widgets (many widgets was using for the DragonArchitect is coded in Gtk+ 2.0),DragonArchitect was designed to be easy to learn without documentation or tips, inspired in the CD Projekt RED, REDKit editor. We currently desiging the visual scripting enviroment i was called the "VisualSka",for map logic, AI, material and compositor effects, avoiding touching lines of code (thing that our artists hate).
The engine currently support the following platofrms: Windows (Too lazy, to test it yet), Linux (Completely tested), Mac OS X (Theorically), Android (Also theorically), Windows Phone 8 (Theorically, also), and IOS (Also, again).
And call ours crazy, but we are researching how-to port the engine for the Haiku operating system.
We can do this?.
Yes, but the school is a priority.