Minetest-WorldEditAdditions/worldeditadditions/lib/bonemeal.lua

--- Bonemeal command.
-- Applies bonemeal to all notes 
-- @module worldeditadditions.overlay

-- strength		The strength to apply - see bonemeal:on_use
-- chance		Positive integer that represents the chance bonemealing will occur
function worldeditadditions.bonemeal(pos1, pos2, strength, chance)
	pos1, pos2 = worldedit.sort_pos(pos1, pos2)
	-- pos2 will always have the highest co-ordinates now
	
	-- This command requires the bonemeal mod to be installed
	-- We check here too because other mods might call this function directly and bypass the chat command system
	if not minetest.get_modpath("bonemeal") then
		return false, "Bonemeal mod not loaded"
	end
	
	-- Fetch the nodes in the specified area
	local manip, area = worldedit.manip_helpers.init(pos1, pos2)
	local data = manip:get_data()
	
	local node_id_air = minetest.get_content_id("air")
	
	-- z y x is the preferred loop order (because CPU cache I'd guess), but that isn't really possible here
	local nodes_bonemealed = 0
	local candidates = 0
	for z = pos2.z, pos1.z, -1 do
		for x = pos2.x, pos1.x, -1 do
			local found_air = false
			
			for y = pos2.y, pos1.y, -1 do
				if data[area:index(x, y, z)] ~= node_id_air then
					if found_air then
						-- We've found an air block previously,  so this node definitely has air above it
						
						if math.random(0, chance - 1) == 0 then
							bonemeal:on_use(
								{ x = x, y = y, z = z },
								strength,
								nil
							)
							nodes_bonemealed = nodes_bonemealed + 1
						end
						
						candidates = candidates + 1
						found_air = false
					end
				else
					found_air = true
				end
			end
		end
	end
	
	
	-- Save the modified nodes back to disk & return
	-- Note that we do NOT save it back to disk here, because we haven't actually changed anything
	-- We just grabbed the data via manip to allow for rapid node name lookups
	-- worldedit.manip_helpers.finish(manip, data)
	
	return true, nodes_bonemealed, candidates
end