WHAT IS OpenGL?

It is a graphics API (others: PHIGS, GKS).
-- The API specifies the interface (library function calls)
-- a graphics API shields the user from the graphics hardware (e.g., implementations of the API can take advantange of hardware when available, but do not require any particular hardware)
-- we issues function calls to the API library.

Industry Standard
-- originates from Silicon Graphics (SGI)

What is supported:
-- relatively small base (e.g. only 10 geometric primitives)
-- geometry-based pipeline architecture
-- 3D graphics
-- basic shading
-- texturing
-- etc

What is not supported:
-- windowing system
-- It is a good thing to be independent of any windowing system.
-- but there are standard library extensions to window systems

Standard and NonStandard Library Extensions
-- glu
-- glX
-- glut
-- OpenGL Auxiliary Library (glAux) was developed in the [Guide], and can be obtained from the internet.
-- Open Inventor is an object-oriented toolkit from SGI.
-- See Appendices C, D, E of [Guide] for glu/glX/glAux.