[Kalki]

Anyone interested in learning about the old engine could start by reading this thread from 1999:

https://groups.google.com/group/comp...3c9f5f8/?pli=1

Been there, done that. I coded what was going to be the Prey engine for the game Prey from 3D Realms; there was an exodus of people from the team, including myself, and the engine has since been scrapped. I'm really not a big fan of portal engines anymore, especially where all rooms are relative (which is what I had) in the manner you propose. There are many ugly problems in maintaining such an engine: two rooms linked by more than one portal (which results in rendering a room twice, basically, and even though they won't overlap, all the culling and transforms are duplicated), graph maintenance with spatial discontinuities, collision detection through portals, handling sound where one sound can seem to be coming from many different locations, rendering characters moving across portals that the z-buffer won't handle correctly, etc. It wasn't fun. The effects were really awesome, though.

In hindsight, portal tricks such as these should be used as tricks, not as an engine paradigm.

William Scarboro