renew/kelp.lua

-- Renew mod for Minetest
-- Copyright © 2020 Alex Yst <https://y.st./>

-- This program is free software; you can redistribute it and/or
-- modify it under the terms of the GNU Lesser General Public
-- License as published by the Free Software Foundation; either
-- version 2.1 of the License, or (at your option) any later version.

-- This software is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
-- Lesser General Public License for more details.

-- You should have received a copy of the GNU Lesser General Public
-- License along with this program. If not, see
-- <https://www.gnu.org./licenses/>.

minetest.register_abm({
	label = "Kelp Spread",
	nodenames = {"default:sand_with_kelp"},
	interval = 30,
	chance = 50,
	action = function(pos)
		local seeds = {}
		local potential_seeds = minetest.find_nodes_in_area({
			x = pos.x - 5,
			y = pos.y - 5,
			z = pos.z - 5,
		}, {
			x = pos.x + 5,
			y = pos.y + 5,
			z = pos.z + 5,
		}, "default:sand")
		for _, seed_pos in next, potential_seeds do
			local water = minetest.find_nodes_in_area({
				x = seed_pos.x,
				y = seed_pos.y + 1,
				z = seed_pos.z,
			}, {
				x = seed_pos.x,
				y = seed_pos.y + 6,
				z = seed_pos.z,
			}, "default:water_source")
			if #water == 6 then
				seeds[#seeds+1] = seed_pos
			end
		end
		if #seeds > 0 then
			minetest.set_node(seeds[math.random(#seeds)], {
				name = "default:sand_with_kelp",
				param2 = math.random(4, 6) * 16,
			})
		end
	end,
})