So is DirectX 8 stuff available to us....like does Microsoft have whatever tools needed for you guys to try and make that upgrade? Is that beyond your abilities?
Yep, you can download the DX8 SDK completely free. The full download is a little large (almost 200 megs) but well worth it. The documentation is excellent.
As far as an API agnostic renderer. That's exactly how FS2 is setup. The high level game code doesn't know whether its in DirectX mode, or OpenGL or whatever. It is indeed handy if you want to be "flexible". However, what I've basically found out over the years is that the agnostic renderer is going to cost you in performance. Not really because of the middle layer, but because every API is slightly different (admittedly, these days they're pretty much all converging to the same feature set) and you're going to be making assumptions to get something working in one API that don't necessarily hold true for another.
For example, if you were to use DX8 you could go full out and create all your vertex buffer and DX8/hardware specific stuff in video memory and work from there. However, there's no analog for that in OpenGL at all (OpenGL likes to "hide" the details from you). So, like in FS2 you write for the common denominator, and do all your transforms on the CPU and use the API as a pure rasterizer.
This brings up a good point. The poster before who talked about OpenGL not being good at "2d" and therefore being slow with FS2 - that's completely untrue. FS2 uses its hardware API (Glide, DX, etc) purely for rasterizing. There should be practically 0 difference between them. I would suggest that the reason your OpenGL implementation is slow is because _you're_ making the wrong assumptions about what the code needs to do and how OpenGL works. That's not meant as a slight - but it illustrates the point very clearly - if you insist on multiple API's you're going to run into ugly roadblocks.
It all comes down to what you want to do with the code. Do you want to take it, possibly make it faster and add a bunch of cool gameplay stuff? If so, stick with Windows, go straight with DirectX 8 and save yourself a _lot_ of time. The whole "we need to use Linux" ideal has always been goofy to me. You're simply not going to beat MsDev for a sleek development environment, you've got a game that works, and DirectX has tremendously useful documentation.
On the other hand, if you just like the idea of porting it to Linux for the sake of porting it to Linux, that's fine. Go with OpenGL and be happy.
But for those who want to actually accomplish something with the game - don't bother. It'll be ages before you see a "useful" OpenGL Linux version and it'll be fraught with incompatibilities and hassles that will hinder your desire to do something with the _game_. You can start right now, this second, doing stuff with the straight up Windows/DX game code. The idea that somehow a Linux/OpenGL port is going to help you is a very silly myth. Cross platform, cross API development is more of a hassle than you need. Let the OpenGL/Linux guys do their thing, it'll be a fun project. But its going to seriously hold you back if you're a simple game developer. If you're really ambitious, someone can be updating the underlying Windows graphics code to DX8 silently underneath you, and I _guarantee_ that if its well written it will be every iota as fast as the mythic OpenGL/Linux beast (in either case, as I said before, simply swapping API's is going to get you knowhere - you're going to need a big effort to overhaul the model rendering code)
(wow, this ended up as a rant).
