C++ OpenGL Debug Utility
Just a couple points (also well done properly qualifying namespaces, a rare thing to see).


#pragma once is non-standard. Meaning it will probably work but is not guaranteed to. Bjarne himself recommends against using it.
Not following your multiple private and public approach. Usually you have a section for each without repeating the keywords.
It makes more sense to order your interface from public to private as people using it don't want to look at the internals of your class, they want to know what methods they can use.
You don't do anything in either your constructor or your destructor. In this case it makes sense to let the compiler take care of them.
Avoid declaring more than one variable per line