My attempt at mapping shader code to radiometric units:

Coutput
= Clight                        I           Radiant Intensity       I   W/sr
/ pow(distance, 2)              I * sr      Radiant Power           F   W
* dot(N, L)                     F / area    Irradiance              E   W/m²
* Calbedo                       E * BRDF    Radiance                L   W/m²/sr

Radiance Coutput is PI times greater than it should be

we can ignore this for video games ...