I want to use opengl in a gtkmm application. I found some widgets like gtkglextmm but that is for gtkmm 2.4 and I'm using gtkmm 3.0. cluttermm isn't in the ubuntu repositories and i'm not sure it's what I'm looking for.
You can use cluttermm (maybe cairomm too, I don't know if it has any direct OpenGL support) by installing it by hand. Shouldn't be a big problem, specially if you use Gnome: get a deb or tarball and install.
Another option is to use another distro which is more develop-oriented. For example, Fedora is RedHat's "sandbox" for RHEL, and RedHat is the biggest sponsor of Gnome and has employees working on Gnome, so on Fedora you find a variety of Gnome packages, including devtools. Including cluttermm :)