Is Glide an OpenGL implementation?
No, Glide is a proprietary 3Dfx API which several features specific to the Voodoo Graphics ™ and Voodoo Rush ™. A 3Dfx OpenGL is in preparation (see below). Several Glide features would require EXTensions to OpenGL, some of which already found in other implementations (e.g. paletted textures). The closest thing to a hardware accelerated Linux OpenGL you could currently get is Brian Paul’s Mesa along with David Bucciarelli’s Mesa Voodoo driver (see below).