OpenGL inherits that legacy of experience in applications development. These functions are provided on every conforming OpenGL implementation to make applications written with OpenGL easily portable between platforms. All licensed OpenGL implementations are required to pass the Conformance Tests, and come from a single specification and language binding document. The OpenGL state machine is a good model for representing graphics problems. The figure above provides a high-level block diagram of how OpenGL processes data.
Commands enter from the left and proceed through what can be thought of as a processing pipeline.
Some commands specify geometric objects to be drawn, and others control how the objects are handled. All elements of OpenGL state, even the contents of the texture memory and the frame buffer, can be obtained by an OpenGL application. Easy to Learn For an experienced graphics programmer, the OpenGL interface is easily understood. However, for someone new to graphics, help is readily and inexpensively available. For more intensive assistance, hands-on classes in OpenGL are available from the Silicon Graphics Technical Education Department.