It just overlays a color on a vertex. This results in…
Like does it create a color gradient between vertecies?
bingo.
They used clever coloring to create the shadow/light effects which where way too advanced for the N64 if you did it the “conventional” way.
Thanks for the answer. My searches on the internet just brought up mathematical graph theory.
It’s so cool to see what simple yet clever tricks they used to use. The tricks used today are probably still very clever but definitely no longer simple.
I got the info from this german youtube channel. https://www.youtube.com/watch?v=EydD_IuSVL0
That guy makes quite interesting stuff. Unfortunately, only in German.