Tiled has some mode where you can paint the tile corners or/and edges to automatically insert tiles. When using only the corners to paint (and only a single terrain type) that would be equivalent to shifting the visual grid by a half tile trick, if I understand correctly?
Adding multiple types of terrain and also making it possible to paint the edges of course will add an explosion of possible tile types that are required. Looks like there is support in Tiled for optional automatic mirroring or rotations to add missing tile variations.
Tiling sprites is a wonderful example of something that starts off relatively simple and then explodes into all kinds of interesting headaches.
In the beginning, you're looking up a set of UVs in a table indexed by some mask value.
In the end, you're debugging errors where one off by one error cascades into strange realms of indexing the wrong (unloaded) chunk with coordinates rolling over to positions that make no sense, looking up neighbours that look one way yet you end up drawing something completely different.
The suggest solution is an elegant and relatively common approach to what would otherwise be a naive series of nested 40+ if statements consisting of much swearing and sprite editing.
There's a lot of explanation here but ultimately this is basically just the standard 16-tile set except assuming you can use rotations to deduplicate and don't need to allocate a tile for empty space. The latter makes sense for platformers (since your tiles likely represent objects that are supposed to be floating over some other background drawn another way) but not so much for, say, RPGs. (And the rotated tiles are often not great in RPGs, either.)
The low tile count simply comes from applying the dual grid approach popularized (if not invented) by Oskar Stålberg to a specific 2d perspective where tiles can be generated through rotations and/or flips.
Oskar does both rotations and flips to his 3D tiles, albeit only in 2 dimensions. He uses basically the same set of 5 tile shapes for any tiles that don't need to take into account verticality (i.e. look at the beach tiles in Bad North)
https://web.archive.org/web/20260213135614/https://www.kyled...
Seems to be getting the hug of death.
Very cool! Sprite Fusion maker here :)