Spherical Harmonics

Note: This post was written nearly 2 years ago and never published. I’m posting it now as-is, with some sections incomplete but the core content intact. This post is a quick crash course on what Spherical Harmonics are and how they can be used to efficiently encode and decode incoming radiance (i.e., a spherical view of the scene) at a point. Motivation Radiance and irradiance In the context of…