Install libgtkglextmm-x11-1.2-doc by entering the following commands in the terminal:
sudo apt update sudo apt install libgtkglextmm-x11-1.2-doc
Description:
C++ bindings for GtkGLExt (Documentation)
GtkGLExtmm is a C++ wrapper for GtkGLExt. C++ programmers can use it to write GTK+-based OpenGL applications using Gtkmm 2. . This package contains documentation and examples.
Homepage: http://www.k-3d.org/gtkglext/
Version: 1.2.0-8
Section: universe/doc