That function editor ... Yet difficult to understan at the beggining, it is damn fun! I've tried this: Many of the materials that comes predefined are made using the function editor. Wth some clicks you'll learn you can make almost any material without having a tiled map of it.

It is very funt trying to do your own materilals. Just try! You can get some ideas by looking at the nodes of the predefined materials. Also, i think I saw some tutorial for the function editor at the tutorials section.

good luck!

you're saying CG sunlight is actually based on a real thing????