renew/marram_grass.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/>.

local nodenames = {
	"default:marram_grass_1",
	"default:marram_grass_2",
	"default:marram_grass_3"
}

minetest.register_abm({
	label = "Marram Grass Propagation",
	nodenames = nodenames,
	neighbors = {"default:sand"},
	interval = 1800,
	chance = 900,
	catch_up = true,
	action = function(pos)
		local candidates = minetest.find_nodes_in_area_under_air({
			x = pos.x - 1,
			y = pos.y - 1,
			z = pos.z - 1,
		}, {
			x = pos.x + 1,
			y = pos.y + 1,
			z = pos.z + 1,
		}, "default:sand")
		if #candidates > 0 then
			minetest.set_node(math.random(#candidates), {name = nodenames[math.random(3)]})
		end
	end,
})