From Scriptionary.com

The OpenGL® API is a platform-independent Application Programming Interface (API) for creating both 2D and 3D Graphics widely used for Professional Graphics and video game development. OpenGL stands for the Open Graphics Library, not denoting an Open Source application but rather an Open Standard. Implementation of this standard is defined by the Independent Hardware Vendors (IHV) and the developers of the Operating System for the specific implementation.

The OpenGL® standard consists of a definition of functions, extensions and data types. No actual functionality is declared in the standard; it simply contains prototypes for functionality.

Origins

The OpenGL® API was created as a replacement for the Iris GL API by Silicon Graphics Inc (SGI) which was the proprietary Graphics API for SGI workstations. An OpenGL® specification was created by Kurt Akeley and Mark Segal for OpenGL® 1.0 to ensure that the API could be adapted for a wider range of platforms.

Because of the API's background in professional applications by SGI, the OpenGL® API was widely considered being the only viable option for professional graphics. The 1996 video game Quake by id Software is often considered the catalyst for usage of the OpenGL® API in professional video game development. The OpenGL® API has been extended by its governing forces, the ARB, ever since to support more features for video game development, competing with APIs such as Microsoft's Direct3D API.

Development

The OpenGL® standard is since 2006 being developed and reviewed by a sub-group of the Khronos Group Inc called the OpenGL® ARB Working Group which comprises of a collection of companies such as NVIDIA, ATi, Apple and id Software. Before 2006 this was done by the OpenGL® Architecture Review Board (ARB) which was part of Silicon Graphics Inc.

Common confusion places the ownership of the OpenGL® API with the Khronos Group Inc. While the Khronos Group Inc develops and maintains the OpenGL® specification since 2006, Silicon Graphics Inc still owns all the applicable rights to the OpenGL® API; The Khronos Group has simply been selected to continue the development of the OpenGL® API.