Simplex3D is an Open souce Scala game engine. It comes with mature
math and data-binding libraries.
The usable engine components are Input System, Scene Graph, and
Technique Manager. You can now create simple scenes and experiment
with writing shaders.
Take a peek at the complete feature list and the project roadmap:
http://www.simplex3d.org/project/roadmap/
Run some examples using Web Start Console:
http://www.simplex3d.org/console/