Brush option where stroke direction = color

Proposal : An option to paint the direction of brush stroke directly on to mesh or texture. Can be used in vertex or texture paint.

You could use it for animal fur, river flowmaps, directional materials, etc. Adds more control for existing hair geometry nodes.

The direction would be determined by screen space and account for object rotation. For vertex paint, it could also align perpendicular to surface normal.

Direction would be normalized vector/RGB, remapped from (-1, 1) to (0,1) like normal map.