Part of my Google Summer of Code project involves porting several arrow heads from Glumpy to Vispy. I also want to make a slight change to them: the arrow heads in Glumpy include an arrow body, I want to remove that to make sure you can put an arrow head on every type of line you want.
Making a change like that requires that you understand how those shapes are drawn. And for someone without a background in computer graphics this took some thorough investigation of the code and the techniques used. This article is aimed at people like me: good enough programming skills and linear algebra knowledge, but almost no former experience with OpenGL or computer graphics in general.