OpenGL (Open Graphics Library) is the computer industry's standard API (application program interface) for defining 2D and 3D graphic images. Before OpenGL, anyone developing a graphical program had to rewrite the graphics part of it for each operating system. They also had to know and understand the graphics hardware. With OpenGL, a program can create the same effects in any operating system using any OpenGL-adhering graphics adapter.
OpenGL designates a set of commands. Each command controls a drawing action or causes special effects. OpenGL works outside the windowing characteristics of each operating system, but it provides special glue procedures that enable it to work in that system's windowing environment.
OpenGL has a large number of built-in abilities requestable through the API. These include:
hidden surface removal
alpha blending (transparency)
antialiasing
texture mapping
pixel operations
viewing and modeling transformations
atmospheric effects (fog, smoke, and haze)
Silicon Graphics began the development of OpenGL.