Setting up Material Domain
First, we create a basic material and set ‘Material Domain’ to ‘Post Process’.

Scaling / Multiplying Viewport UV
For manipulating the Viewport UV, we are gonna use the Screen Position node.
With this, we can multiply ViewportUV with a scalar parameter (use floor node to round down to your value the next integer/example: 0.1 would be 0 and 4,8 would be 4).

Rounding down values from the ViewportUV
With this, we are rounding down the values from our ViewportUV multiplied by our Pixel Count scalar parameter.

Dividing by our “Pixel Count” parameter
In the end, we need to divide our rounded value by the same amount that we used in the beginning as Pixel Count.

Shader Overview
In the end, we need to divide our rounded value by the same amount that we used in the beginning as Pixel Count.
