buffer objects aren't available from the OpenGL module

But they are (as an "extension)! I did some research before starting with OpenGL and found the wikipedia article Perl_OpenGL. I got the POGL Sample Test App linked from there working. Understanding that code, on the other hand, took some time, and I would have surrendered, but then I found the ancient guide.

The example does not work with OpenGL::Modern which no longer provides glGenBuffersARB_p.