@codeanticode
I would just like to point out that in addition to a normal() function for every vertex, a function such as diffuse() would be lovely so that the greatest angle that the light bounces off to can be changed. As it is, Processing is very frustrating when trying to create uneven ground. The vertex as the top of hills have to have their normal face straight up and so the light often doesn't reach the "eye" of the camera resulting in some very odd and distracting shading bits that flash and disappear when you get close:

This function would also be really useful for other objects, allowing the user to decide how much shadow is present based off of the object not the light. It would create more contrast and definition.
Thanks for your time!
(this was originally in another section but has now been moved to here)