Autotiler Lite - 16-tile auto-tiling for Tilemap

Give a tile sixteen sprites and paint with it, and edges, corridors and outside corners resolve themselves from the four cells around each one. Four neighbours is the easy half of auto-tiling, and it is easy for a reason worth knowing: there are sixteen possible neighbourhoods and sixteen sprites, so the mask is the index. Nothing has to be folded and no rule has to be applied. A cell resolves in one array read. This package is complete. No trial, no watermark, no time limit, source included. The import settings are not cosmetic: three defaults quietly ruin a tileset, and all three produce a map that looks almost right, which is the hardest kind of bug to find. Compression puts colour artefacts along the one-pixel seam where two tiles meet. Mip maps soften every tile the moment the camera is not at 1:1. A Tight mesh trims transparent border pixels, and two tiles trimmed by different amounts stop lining up. The window sets Point filtering, no compression, no mip maps, Full Rect and extrude zero. Put terrain B in terrain A's also counts as mine list and terrain A in terrain B's. Neither draws an edge against the other, so the two read as one continuous piece of ground that changes material. Four neighbours cannot express an inside corner. A cell whose four sides are all terrain is mask 15 whether its diagonals are terrain or not, so the same sprite is drawn in both cases, and one of those two cases wants a small notch where the terrain curls around a corner. Getting that right needs all eight neighbours: 256 neighbourhoods, 47 distinct appearances, because a diagonal only counts when both orthogonals beside it are present. If sixteen tiles is all your art has, this package is not a cut-down anything. It is the whole job.