Resolved 80s style grid shader noise

This is a tricky problem. The issue you're seeing is aliasing - which is a classic issue in computer graphics that engineers have been trying to solve for decades. When you sample a texture, for example, the graphics hardware has built-in hardware for filtering to solve this problem.

You're generating the pattern procedurally, so you have to build the solution into your graph itself rather than relying on the hardware to do it for you. If you sampled a small grid texture instead of using a procedural solution, that would probably be the easiest way to solve it.

Another solution would be to generate the grid using a Signed Distance Field - where up close and when looking straight at it, the SDF produced sharp results, but at glancing angles and further away, it produced slightly blurry results. If I get some free time this week, I'll see if I can implement something like that and post it. In the mean time, see if you can implement the solution that Inigo Quilez developed that's quoted in the Stackoverflow link that NXRT_MA posted above.

 

Great work, congrats!