The problem is that DX10 is fundamentally different from all previous versions of DirectX.
DX10 is not natively compatable with any earlier versions, there is however a software emulation that allows games made with previous versions to run on DX10 machines.
This is the first version of DirectX that has dropped backwards compatibility as a feature. This has more to do with how Vista is designed at a fundamental level than anything else, in short MS does not want to support two fundamentally different architectures for the forseeable future.
For DBPro this means that they are either going to get stuck supporting two versions or like MS just create a new product and say: "This one is DX10 and this one is DX9, (btw support for dx9 will be dropped on such and such day".
Ive got no idea how they will do it, they could just merge all the DX10 stuff into DBPro and say "Have at it" but I suspect they will be flooded with bug reports from DX9 folks trying to do DX10 stuff on DX9 machines. Confusion.
So, any DX10 game will only work on DX10 hardware and Vista, anything that takes advantage of DX10 features will only be able to run on DX10 hardware/software. DX9 and lower software does run on DX10 hardware/software but does so via a software emulation layer.
-Gooney
Uboats in space...hmmmm. Aces of the Vaccuum?
