Extensions to OpenGL

Extensions to OpenGL

The OpenGL standard is designed to be as portable as possible and also to be expandable with extensions. Extensions may provide new functionality, such as several video extensions, or extend existing functionality, such as blending extensions.

An extension's functions and tokens use a suffix that indicates the availability of that extension:

EXT is used for extensions reviewed and approved by more than one OpenGL vendor.
SGI is used for extensions found across the Silicon Graphics product line, although the support for all products may not appear in the same release.
SGIS is used for extensions found only on a subset of Silicon Graphics platforms.
SGIX is used for experimental extensions: In future releases, the API for these extensions may change, or they may not be supported at all.

The glintro reference page provides a useful introduction to extensions; many extensions are also discussed in detail in the following chapters in this guide:

Note that both the X Window System and OpenGL support extensions. GLX is an X extension to support OpenGL. Keep in mind that OpenGL (and GLX) extensions are different from X extensions.