Simple real time hair cutting

Hello, I was curious how real time hair cutting is being done (probably it’s not really hard and resource consuming since mobile games have it)
Example: https://www.youtube.com/watch?v=db3x1Fic_bo

My thoughts: few “hair cards” meshes with different lengths
On collision with the clipper it’s being replace with a shorter version
For gilette shaving → very short hair cards + uv map?

Maybe it could be possible in Groom? Cutting hair by root uv?

Or maybe I’m completely wrong?

Thanks in advance