I've updated GtkGLExt's support for OpenGL extension APIs along with
some bugfixes and this work is in a local git repo for now. GtkGLExt
seems largely unmaintained now, and it's something we want to use
in Herb. There is more work I want to do such as
make the convenience library more GLee like, and also move the
git.gnome.org. So I'm going to ask the
current maintainers if they can pass the baton.
Here is an example of GLSL in use (C source code for this is available in the repo). This was adapted from a Ruby example on the net (credited in the code).