Repeated texture on a tilemap

This is a demo of a very simple shader that overlays a texture across a tilemap using Godot 4.3

See equivalent version for Unity here: https://github.com/jess-hammer/repeated-texture-on-tilemap-demo-unity

The texture:

The result:

Example tile set:

It will only overlay the provided texture across the parts of the tiles that are fully red, so that the edges can be preserved in the final result.