Hey, i am a bit confused about this whole rotation thing of game programming. How do i rotate a system around an arbitrary axis. I am trying to control my system like a standard fps camera is controled. I think the only way to do this is to rotate around the "up" vector of your camera when turning side to side, and around the "side" vector when i want to look up and down. My question is how do i go about rotating a xyz component vector around another xyz component vector. I have heard quaternions might be my answer but i dont understand these very well. I will go research anything i just need to be shown the right direction.

This engine i am writing is software only and only uses the most basic of sdl routines. the only API i wanna use for this program is blitting and opening a window.