In this tutorial I showcase a couple of different ways to quickly add lighting to a 3D model when all you have is the normal vector. I also get opinionated about the ambient component of the Phong model.

Links:
Quick Lighting Tech https://www.shadertoy.com/view/ttGfz1
Explanation of the "erot" function https://suricrasia.online/demoscene/f...
"Computer Color is Broken" i.e. why we take the square root at the end    • Computer Color is Broken