What information is available about OpenGL extensions?
Examples of extensions include vertex arrays (calling several vertexes or related data, such as normals or colors, with a single function call), blending of constant colors, polygon offset (multiple coplanar polygons can be rendered without interaction), Procedure names and tokens for OpenGL extensions are either suffixed with EXT or a vendor-specific acronym: such as SGI for Silicon Graphics machines, or INGR for Intergraph. Also note that Silicon Graphics extensions to OpenGL are suffixed to indicate whether they will be available on all machines (SGI), on just a subset of machines (SGIS), or are very experimental and may become unavailable or completely changed (SGIX). Vendors are encouraged to add extension information to their documentation. For Silicon Graphics, extension information is summarized on the glIntro man page.
