Can it be done without writing a function for every DirectX function, or can you use some COM trick to make it easier?

Yep, wrap every function.

You can't "derive" anything from COM, regardless of language, because COM has no support for virtual functions. To get true C++ style objects, make a new class, wrap all the DirectX calls into similarly named functions, then derive / make virtual whatever you want.

Or, be lazy and just expose the interface directly in your base class.

Mason McCuskey
Spin Studios
www.spin-studios.com