Kreldin

Hi, I've been learning C++ for some time now and I would like to make a basic game. But I have some questions about game programming in general - I really don't know the difference between (or the uses of) things like DirectX, OpenGL, etc.

From what I understand, DirectX and OpenGL are APIs... what exactly is an API, why/when would you use them for a game? What is something like XNA, then?

Further on, from what I understand, things like SDL and SFML are libraries - how are they separate from things like DirectX and OpenGL, are they used together/in conjunction? When would you use one over the other?

Finally, there's Unity, which from what I understand is an engine. So can you just use something like Unity to make a game and ignore the rest?

Thanks

I've been learning C++ in college, only 3 classes in, but I have a nice understanding of the language and I've been doing great. However, I am interested in expanding and learning game development. Just don't know where to begin, really. I hear C++ is too hard for a beginner to get into game programming, and that I should look into C#. (And for my first project, I want to make a 2D RPG, in the style of a Final Fantasy game).

If so, what library would I use to begin? I hear XNA is a great choice, but wanted a second opinion. I just never dabbled in C# before. Should I just stick with C++, as that's what I'm learning at school, and try to use the SFML library?