"Diesel Engine: An OpenGL Quake3 Arena Map Viewer, written in c++. It supports a variety of features including volumetric fog, portals/mirrors, items, basic entities, skyboxes/cloudlayers, videotextures and multitexturing for up to 6 texture units. Open source, GPL" <-- this might be misleading but I'm not sure...
Sounds good so far if GRIN is using OpenGL... can someone elaborate?
I found another article... ie GRIN & Diesel Engine... Case Study Gallery - GRIN
"Thatââ¬s why GRIN has developed their own 3D-engine, called Diesel Engine, a robust multi-purpose platform. The 3D-engine is the heart of the game and determines how things behave in the gaming environment. It handles movements, bump mapping, specular lighting, bones, chrome positional sound and music, as well as dynamic surfaces and more. All this comes together to insure that there are no limits when developing a GRIN game."