That's where I learned about the transference phase function (slide 24), which includes two spikes on the return angle that correspond to the relatively unknown Glory rainbow: https://en.wikipedia.org/wiki/Glory_(optical_phenomenon)
I don't know if this method is what is used in video games today.
You can see screenshots of that work in his thesis defense slides https://theses.hal.science/tel-00319974/file/defense.pdf
That's where I learned about the transference phase function (slide 24), which includes two spikes on the return angle that correspond to the relatively unknown Glory rainbow: https://en.wikipedia.org/wiki/Glory_(optical_phenomenon)
I don't know if this method is what is used in video games today.
Incidentally, you may recognize his advisor Fabrice Neyret as someone very active in the Shadertoy community https://www.shadertoy.com/user/FabriceNeyret2