1, open Graphic Library
2, Is a standard specification defining a cross-language cross-platform API for writing applications that produce 2D and 3D computer graphics
3, OpenGL was developed by Silicon Graphics Inc. (SGI) in 1992. now is managed by the non-profit technology consortium, the Khronos Group, Inc
4, It is also used in video games, where it competes with Direct3D on Microsoft Windows platforms
5, Before openGL, many hardware vendors had different graphics libraries. This situation made it expensive for software developers to support versions of their applications on multiple hardware platforms, and it made porting of applications from one hardware platform to another very time-consuming and difficult.
6, Example http://www.sgi.com/products/software/opengl/examples/index.html
7, openGL is the graphic engine for android