particlefountain/init.lua

local update_formspec = function(meta)
	local pos = meta:get_string("pos")

	meta:set_string("infotext", "Add item block: pos=" .. pos)

	meta:set_string("formspec", "size[8,7;]" ..
		"field[0.2,0.5;2,1;amount;Amount;${amount}]" ..
		"field[2.2,0.5;2,1;glow;Glow;${glow}]" ..
		"field[4.2,0.5;2,1;height;Height;${height}]" ..
		"field[6.2,0.5;2,1;spread;Spread;${spread}]" ..

		"button_exit[6.1,1.5;2,1;save;Save]" ..
		"list[context;main;0.1,1.5;1,1;]" ..

		"list[current_player;main;0,3;8,4;]" ..
		"listring[]" ..
		"")
end

minetest.register_node("particlefountain:particlefountain", {
	description = "Particlefountain",
	tiles = {
		"default_gold_block.png^default_mese_crystal.png"
	},
	groups = {cracky=3,oddly_breakable_by_hand=3},

	on_construct = function(pos)
    local meta = minetest.get_meta(pos)
		meta:set_int("amount", 4)
		meta:set_int("glow", 9)
		meta:set_int("height", 2)
		meta:set_int("spread", 1)

		local inv = meta:get_inventory()
		inv:set_size("main", 1)

    update_formspec(meta, pos)
		minetest.get_node_timer(pos):start(2)
  end,

  on_receive_fields = function(pos, _, fields, sender)
		if not sender or minetest.is_protected(pos, sender:get_player_name()) then
			-- not allowed
			return
		end

		local meta = minetest.get_meta(pos);

		if fields.save then
			meta:set_int("amount", tonumber(fields.amount) or 4)
			meta:set_int("glow", tonumber(fields.glow) or 9)
			meta:set_int("height", tonumber(fields.height) or 2)
			meta:set_int("spread", tonumber(fields.spread) or 1)
		end

		update_formspec(meta)
  end,

	allow_metadata_inventory_put = function(pos, _, _, stack, player)
		if minetest.is_protected(pos, player:get_player_name()) then
			return 0
		end

		return stack:get_count()
	end,

	allow_metadata_inventory_take = function(pos, _, _, stack, player)
		if minetest.is_protected(pos, player:get_player_name()) then
			return 0
		end

		return stack:get_count()
	end,

	on_timer = function(pos)
		local meta = minetest.get_meta(pos)
		local inv = meta:get_inventory()
		local stack = inv:get_stack("main", 1)
		local node_name = stack:get_name()
		if node_name == "ignore" or node_name == "" then
			return true
		end

		local def = minetest.registered_items[node_name]
		if not def then
			return true
		end

		local texture = "default_mese_crystal.png"

		if def.inventory_image then
			texture = def.inventory_image

		elseif def.tiles then
			if type(def.tiles) == "string" then
				texture = def.tiles

			elseif type(def.tiles) == "table" and #def.tiles >= 1 and def.tiles[1] then
				texture = def.tiles[1]

			end
		end

		local spread = meta:get_int("spread")

		minetest.add_particlespawner({
			amount = meta:get_int("amount"),
			time = 2,
			minpos = vector.add(pos, {x=-spread, y=0, z=-spread}),
			maxpos = vector.add(pos, {x=spread, y=0, z=spread}),
			minvel = {x=0, y=1, z=0},
			maxvel = {x=0, y=2, z=0},
			minacc = {x=0, y=0, z=0},
			maxacc = {x=0, y=0, z=0},
			minexptime = 1,
			maxexptime = meta:get_int("height"),
			minsize = 1,
			maxsize = 1.7,
			collisiondetection = false,
			collision_removal = false,
			object_collision = false,
			vertical = false,
			texture = texture,
      glow = meta:get_int("glow")
		})

		return true
	end
})