If you've looked at the box that your video card came in, it will say often state that it is OpenGL 2.0 and DirectX-10 compatible or something like that. Using these graphics libraries is about as low-level as you want to get as the hardware was designed to be compatible with these.
So check out a tutorial or two on one of these libraries and think about how you can wrap it to make your library in a way that will be easy for you to interface with it.