Worldgen Devtools

The mod is a development aid for creators of world generation datapacks and mods. Reloading worldgen data from the reload command, with a gamerule to enable it per world, lets an author test changes without reopening the world. Entries removed from a datapack stay in registries while they are still loaded, and an outdated entry only stops affecting generation once it is marked as such, so the world-height noise shape and height cell size cannot be reloaded. Existing chunks keep using outdated entries until the world is reopened. Because reloads can corrupt worlds, the author recommends enabling the feature only in testing worlds.

The resetchunks command regenerates the chunks around the player within a chosen range, using the current worldgen data, and defaults to the current chunk alone. Reset of a structure start needs its chunk reset as well. Jigsaw blocks are colored by their Name and Target Name: a block whose name matches another block's target is tinted by that name's hash, and a block with both set to minecraft:empty is drawn grayed out with no connector arrows. Biome colors and dimension types on the client are changed by reloads only in multiplayer when the synchronization gamerule is active, which causes clients to redraw chunks. Fabric API is required.