Yeah its just a shader. Since its written in GLSL, it doesn't work on DirectX and my engine doesn't even have a DirectX render. Not sure will I ever implement a DX renderer, the architecture of the rendering in the engine would allow that to be done pretty easily I think, so if I ever decide to properly learn DX, then I might just implement a renderer for DX too . But for now, just OpenGL .

As for other engine features: simple physics are already in (BOX, SPHERE, TRIMESH collision shapes, adding force and torque, setting velocity), joints and more collision shapes will probably come later on. Also collisions register to the objects and rays for the user to read (collision position, normal, depth, colliding object).

Light and scene management is pretty simple at the moment. Some simple occlusion and light culling is in already, will work on that more when I get to it (as said, the current priority is to finish stuff for Alpha 3, for example the fbx converter)

User interface elements are completely skinnable (actually there are no default skin elements for them so you HAVE to skin them). The following user interface elements are implemented: Labels, Button, Pictures, Text Fields, Screens, Sliders (more like gauges, works similarly to a slider), Text Lists, Check Boxes