Final:
Overview and Node setup:
You can use node setup with dots. The requirement is to have proper UV map. As far as I can see in your picture you have triangulated mesh so it will be a little bit harder to UV Unwrap it. I have used Follow Active Quad method (check it in my answer) but I have created quad based mesh.
As for the node setup it's from someone else (can't remember where I've found it).
You can manipulate dots size, position and gaps between them by three Value nodes. Also near the end of this setup there are two Mix RGB nodes, one is for Bump node (black and white colors) and second one for wall and holes colors. You can also make second one as a mask for some advanced texturing. Note that I'm using Principled BSDF from Blender 2.79 RC2 but you can use any shader you want.
