I’ve barely had time to look at XNA, but one of the first hurdles I’ve seen so far is loading a mesh in the traditional .x format.
In the past the DirectX SDK’s Managed DirectX libraries contained support for using the .x format. However XNA does not…well, not yet at least. XNA was supposed to include something called the “Content Pipeline”, which would have supported the .x format. However, at the last minute Microsoft held back on including the Content Pipeline. I guess it wasn’t ready for public consumption.
It does support some other format .swm, which appears to be propriatory. Until the Content Pipeline is released (hopefully soon), the work around seems to be to convert your .x format meshes into this .swm format.
I see over at XNA Spot that there is now a converter. It’s on their samples page. I haven’t tried it yet, but fingers crossed I’ll have the ol’ Spitty rendering real soon.
Oh yeah, and I have to learn HLSL too. That’s “High Level Shader Language”.
eeek!!! 
September 7th, 2006 at 7:33 am
Is a HLSL similar to the rendering languages created by NVidia and ATI for their specific cards?
– JD
September 7th, 2006 at 8:04 am
As far as I know, HLSL is a directX standard, that compliant hardware has to handle.
Hardware branded as “DirectX 8″ does Shader model v1.1. Hardware branded as “DirectX 9″ does Shader model v2.0. I think there is also a Shader model v3.0, but I’m not sure what/if any hardware does that yet. Probably a Vista/DirectX 10 thing.
Anyway, to answer your question. I believe nVidia & ATI have some optimized “features” that can be exploited, but the language itself is probably the same.