The following extra Gtk GL level functions are provided by Guile Gtk.
Make the given area current, throwing an error if this fails.
Evaluate the body forms with area made current. An error is thrown if area cannot be set.
with-gl-areajust sets the area,
with-render-to-gl-areain addition calls
gtk-gl-area-swap-buffersafter body, to display whatever body may have drawn to the back buffer.