Introduction
It has been a long time since my blog post (because of Covid, work, Elden Ring...). So I decided to study the "Spectral Primary Decomposition for rendering with sRGB Reflectance" , which used in previous posts, to recall my memory. It is an efficient technique to up-sample sRGB texture to spectral reflectance by multiplying the sRGB values with 3 precomputed basis functions:
Porting to Octave