Game Engine Architecture

[kilgariff]

I'm quite interested in game engine design, and find myself constantly re-writing segments of my engine whenever I hear of or realize a better way of doing things. I'd like to discuss some different parts of the typical engine, and maybe try and get an idea as to what most people do when they are faced with a problem.

Right now, for example, I'm trying to come up with a reasonably good design for a scene graph. I am stuck between a number of options, including making "in-game objects" or "entities" inherit from a base Node class that can point to numerous Node children, and then traversing the tree of nodes while concatenating transformations and preparing the ones that _are_ objects for rendering via pure virtuals. The opposing thought is to have only the leaves of the tree as actual in-game objects, and the nodes just connect and group them.

How do other people implement things like scene graphs?
(does anyone else do 3D, for that matter? Because that would kinda help..

Note that by in-game object, I mean everything from static meshes and particle emitters to event triggers and even cameras.


Also, if you want to ask any questions about some other piece of engine design entirely, fire away.