How to create an HSL color Keyer

Hi everyone, how are you guys doing?

Does anyone know how to create an HSL keyer using GLSL?

I am trying to create a keyer similar to the one in Davinci Resolve for those who are familiar with the program.

I already found some great code on GitHub to convert RGB color space to HSL and then back.

But I can’t find any information on how to use this to create a nice keyer.

Does anyone know how HSL keyers work and how to make one in GLSL?

I would really appreciate any information I can get.

Thanks in advanced!!

Shem Namo