tl;dr: This was a neat little article, where the author covers how they’re building shaders into their (C++?) software renderer. They even have a demo video or two where they show their small shading engine coloring a spinning cube, OpenGL style!
My main nit is a stylistic one: The author has a vendetta against Capitals at the start of sentences, and it made reading their work much more difficult for me, because my eyes would skip past the end of one sentence, smack into the next one, and then I’d have to go back and re-read. After doing that for 2-3 paragraphs it was no longer a cute quirk, it was just annoying.