Donjon Regen — an offline renderer + editor for donjon.bin.sh's dungeon JSON exports

donjon.bin.sh's 5e dungeon generator is great, but once you generate and export the JSON you're locked to the map and have no way of editing it or re-viewing it. So I had AI reverse-engineered the export format and built a tool that re-renders everything locally and offline, and then lets you edit the result.

What it does:

• Reads donjon's exported JSON and re-renders the GM map, player map, a clickable HTML doc, and TSV/CSV — all offline.
• Maps are drawn procedurally with Pillow: rooms, corridors, polygon/circle rooms, stairs, and the full door set (arch / door / locked / trapped / secret / portcullis). Door and stair glyphs are generated as pure integer pixel art at the target cell size; no resampling, so lines stay crisp at any scale.
• A desktop GUI turns it into an editor: paint corridors (with auto-door placement), create / delete / reshape / resize rooms, resize the canvas, mirror rooms, and edit room contents/monsters/treasure/doors.

The procedural-gen-relevant bits were the fun part: donjon packs everything into a 2D array of integer bitmasks (block / room / corridor / wall / aperture / room-ID / door-type / stair / label-char bits), with a symmetric padding offset between the cells array and the map coordinate space. I documented the whole encoding in the repo since I couldn't find it written down anywhere.

Repo: https://github.com/DawnGuardian/Donjon-Regen Release: https://github.com/DawnGuardian/Donjon-Regen/releases/tag/v1.0.0

Happy to answer anything about the bitmask format or the rendering pipeline. (Full disclosure: the code was written with AI assistance but the tool's output is fully deterministic, no AI-generated content.)