Possible Duplicate:
OpenGL or DirectX?
I've been looking on the internet for some time now, I've even read this post: OpenGL or DirectX?
but it either doesn't really tell me exactly what the difference is or people just post "what they think they know" about it.
I really want to know exactly what is the difference between them so that I can at least try and make my own judgement on which API to use when create my games.