I'm working on a tile-based 2D pseudo top-down/side-on game very much in the graphical style of Prison Archiect. More specifically, I'm referencing their style of drawing wall tiles where you can see the south, east and west sides of the wall at once. Here's an example from my engine:
I'm also working on a pixel-based (i.e. not tile-based) lighting and shadows implementation. I'm currently struggling with trying to decide how/where to project from a light source on intersections with these wall tiles.
I can't decide where on these tiles should occlude light cast out by light sources. If the red highlighted areas are the "top" of the wall, and the blue highlighted areas are the "side" of the wall, I believe I have two options:
A) Only occlude light from the "top" of the wall
It's worth mentioning that I also plan to use UV-mapping so that only the walls facing the light source will be illuminated, rather than the pre-shaded tiles I'm using as an example. However, that would mean that the tiles adjacent to a wall in shadow may be lit and I don't think this would look quite right. Alternatively...
B) Occlude light from the entirety of the wall tile
This seems more realistic for the ground tiles but does not let me easily illuminate the wall "sides".
I'm not really happy with either solution so my question is: is there another alternative which will give more realistic shadow-casting in a 2.5D view? I'd also rather keep the sides of the walls visible rather than use a top-down only perspective as I feel this would force the rest of the art into a top-down perspective, rather than pseudo side-on.