Can I add code in the supplementary material of my thesis which builds up on an existing library?

I’ve written a thesis in the context of global illumination. The explorations are purely theoretical, but I’ve implemented the basic building blocks of the described approach and would like to add this implementation to the supplementary material of my thesis.

Since my work focuses on a particular aspect of the complex rendering pipeline, my code builds up on and extends an existing library (http://www.pbr-book.org/).

The code fragments I want to put in the supplementary material don’t include anything of the code from that library, but it clearly references classes, functions, etc. from it.

My question is: Is there something I need to be aware of? Do I need some kind of permission from the library authors or add a particular disclaimer (apart from providing a reference to the original library, of course) to my thesis?