How to write a shader that will drop vertices?

Question

Shaders

There is a video:
https://yandex.ru/efir?stream_id=49ae679600727c009...
at 34:54 a shader is written that makes rounding. What needs to be added so that albedo and normal map can be added to this material? (if something is not clear - write in the comments. I'll try to explain. I'm just a beginner in this business))