Simple triangle interpolation

I’m trying to create a system whereby I can, in theory, define a physical level by any number of triangles, which I can walk on, jump onto / off of, run up, run down, and maybe even slide off . And this isn’t exactly an OpenGL-specific question but this is the best msg board I know .
My problem: I don’t really know how to do this.
I’ve made up my mind that I’m going to be using an Octree system, because apparently it performs better on outdoor scenes (my levels will be like Mario64).
My first idea was for the player to have a bounding box - but then I remembered I know nothing about those (I have the Quake I source but can’t understand the SV_Phys.c physics file). Then I thought as I have a line-triangle intersection routine (although it only returns TRUE or FALSE), I could trace down from the player, then up, left, etc. until I’ve done about 16 different rays, then I could find out if i’ve hit anything…but this is obviously rediculous, the game would run too slow.
Could you help me with this please?


p.s. oops, forgot to ask - how can I find out (for example) the height of a point in a triangle if I’m at offset x,y from point A?
p.p.s. but don’t just read my p.s. and answer that, there’s more…hehe

[This message has been edited by Fugit (edited 08-29-2000).]