The glVertex library emulates the legacy OpenGL API, which has been deprecated in OpenGL core profiles. It is also a convenience wrapper around GLSL shaders, VBOs and FBOs.
Crystal Space is an Open Source 3D SDK for Unix, Windows, and MacOS/X. It renders with OpenGL and features GLSL shaders, CG shaders, deferred rendering, dynamic shadows, bullet based physics library, terrain engine, skeleton based animation meshes, exporter for Blender, portals, etc...
Networix is a Open Source Framework programmed in c# to allow users to script in lua, c# and GLSL in a OpenGL Environment using an object based interface.