Created a repository - https://github.com/Lumak/Urho3D-1.4-SphericalHarmonicLighting/ if anyone is also interested in this topic.
Made a couple changes in the repository.
Thanks for sharing. Do you know a tool to generate SH coefficients from HDR image?
At the time I wrote it, I saw several code that generated SH coefficients but didn’t seen any tool for it. I’m not a graphics guy but wrote this as a learning exercise to learn a bit about SHL was how they work. There might be a tool now but I haven’t kept up with what’s new.