How would I use OpenBSP?
OpenBSP is a file format that is used to hold a 3D scene. The format includes light mapping (for shadows) and bumpmapping (for shadows on rough surface eg a cobblestone path). Quake has its own BSP format for storing Quake maps. OpenBSP is similar except that it is open source and has extra features that the IDSoft Quake format doesn't have such as bumpmapping. OpenBSP loads directly into the GLScene GLFreeform making it easy to incorporate into your GLScene application.
The typical way to use OpenBSP is to create a Quake map with Quark, compile it with OpenBSP then incorporate it into a Delphi application using GLScene.
Why use OpenBSP compared to normal BSP?
If you use the IDSoft BSP format commercially you must pay a license fee of $US50000. Currently there is no license with OpenBSP but Osman (the guy who wrote OpenBSP) hopefully will make it better than than the IDSoft license. Also its been designed specifically to be used with GLScene therefore has features GLScene users want such as leaking maps (eg you can create a town without enclosing it in a box) and in the future things like lists of entities (eg positions of lights sources).
Where can I get it?
The latest OpenBSP source is at www.osmanturan.com.
If you're after an install that includes Quark with OpenBSP as the default compiler check out:
It includes a GLScene demo with source that uses OpenBSP as its game application so you can edit your map, compile it then run it with the GLScene app.
Heres a few screenshots