How Mossmeal works
In vanilla Minecraft, using bone meal on a moss block only works when there is air above it — the moss patch spreads across the floor and grows grass, moss carpets and azaleas. Mossmeal extends this exact mechanic to the two remaining directions.
When you use bone meal on a moss block attached to a wall, the mod finds the exposed wall surface and spreads moss across it in a circular patch with a radius of 2–3 blocks. Any block in that area that moss can naturally replace — stone, dirt, gravel, coarse dirt, rooted dirt, diorite, andesite, deepslate, tuff and similar — is converted into a moss block. The edge of the patch is randomly ragged so it looks organic, and the spread follows uneven surfaces up to two blocks deep, so it works on rough cave walls, not just flat ones.
When you use it on a ceiling (a moss block with air below), the same moss patch spreads across the ceiling — and instead of the floor vegetation, glow berry vines grow downward from the new moss. Each vine has a random length, mostly 1–4 blocks with an occasional longer strand up to 7, and roughly a third of the segments already carry glow berries. Vines are placed with at least a one-block gap between them so they never clump together, and at least one vine is always guaranteed at the spot you clicked. Vines stop early if something is in the way, and existing vines are never overwritten by the moss spread.
Floor behavior is completely untouched — if the moss block has air above it, the mod steps aside and vanilla takes over. The whole thing also works when the bone meal comes from a dispenser, and since the logic runs server-side, it behaves identically in singleplayer and on servers.
