Time for another node test: I played around the idea about doing proper dithering completely inside blender just by using compositing nodes and here’s the result:
Rendered at 160x200 (honoring c64 double wide pixel aspect):
The dithering uses ordered 4x4 matrix implemented via math nodes, it’s probably the least effective way of doing this but hey, it can be done!
It would be really cool to actually fit the end result to a fixed palette but doing with plain math nodes would be a total performance killer and i’m open to alternative ways to handle it inside compositor nodes.
The compositor nodes have a switch to show external images if you want to just test the output:
And here’s a comparison image between the rendering and output:
And finally here’s the blend file: http://xard.mbnet.fi/blenderartists/b28_4x4_positional_dither.blend