[Phylum]

SDL is also good, but is written in C so things don't always make 100% sense in a C++ context. But hey when do they?

I'm going to stick my neck out and say to use D over C++, but that's probably just me being controversial. I have minimal C++ experience by choice, because I just found it incredibly unpleasant to work with. At the moment I'm not afraid to say that I prefer wrestling with C, although I'm still doing a few smaller D projects on the side to get more fluent with it.

e: Actually, most (all?) of the time you have to deal with structs in SDL it gets abstracted by methods, so they look like objects. It would fit pretty well with the style of C++ code. I don't really know if that's a good or a bad thing at the end of the day.