Please bear with me on this, I know it's a long question and I apologise :\
I've been using the BSP entities plug-in, provided by www.realgametools.com. This works fine, I've modified the example code to do the following with basic Half-life maps:
1. Load a BSP world and position the camera at info_player_start
2. Allow player movement using W,S,A and D keys, and the mouse
3. Position a 3D sound within the level.
4. Create point lights for all the BSP lights.
5. Spin a 3d cube object in the main room.
You can download all the source and media files in my demo from here:
Check it out, it's quite spooky.
there are problems.
1. When I initialise a cross-hair sprite, it messes up the textures of the BSP world (see the code).
2. Any 3d objects, such as furniture or people, are not lit using the BSP world lights. Ok, so I could interpret the light entities and create lights for them, but BSP walls could not block light or sound created in Dark Basic. Furthermore, how can I cast shadows onto a BSP world?!
If you run my demo, you can see that the spinning cube object is indeed lit, but not by just the light source above it... There are 3 lights in the whole level, and all of them seem to affect the cube.
So what can I do to light 3d objects in a BSP world?
Any other advice from people who have played around with BSPs would be much appreciated too!
p.s. Sorry I haven't included the original .map file, but it's fairly simple. Let me know if you want this too.