> A graphics library is usually divided into 3D like *GL variants and 2D like SDL
OpenGL (what I assume you are referring to by *GL) is both 2D and 3D; it also, as one might expect of purely a graphics library, doesn't provide control events or audio and considers that something else's problem.
SDL ("Simple DirectMedia Layer") does do things like control events and audio, but does not describe itself as a graphics library, but as "a cross-platform library designed to make it easy to write multi-media software, such as games and emulators."
OpenGL (what I assume you are referring to by *GL) is both 2D and 3D; it also, as one might expect of purely a graphics library, doesn't provide control events or audio and considers that something else's problem.
SDL ("Simple DirectMedia Layer") does do things like control events and audio, but does not describe itself as a graphics library, but as "a cross-platform library designed to make it easy to write multi-media software, such as games and emulators."