Brushstroke-based filters?

Hey everyone, I am working in Substance Painter and my goal is to paint a base colour layer with the individual brushstrokes being simultaneously saved on a greyscale texture (I am using the height channel for this). My idea for achieving this was to have a filter affecting the height channel which applies a horizontal gradient to each brushstroke (since that way the individual brushstrokes could be discerned).

I cannot seem to figure out how to get the gradient filter (or any filter, at that rate) to apply on a per-brushstroke basis - it only ever applies either to the whole mesh or to the whole painted layer.

Does anyone know how to get this brushstroke-based gradient effect? Any help would be appreciated.