How to create a lot of procedural textures?

I have a fairly simple yet another question about procedural things.
I know from here and here how to UPDATE some texture.

It’s useable if you have a single point of interaction - e.g. one whiteboard in a room.
But imagine a thousands of white boards. There’s different drawings on each of them. So my question is simple: how to create NEW texture in C++, or maybe it’s possible to instantiate lots of different versions of the same texture (sounds weird)?