Add the "entity detector" node

moremesecons_entity_detector/depends.txt

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+mesecons

moremesecons_entity_detector/init.lua

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+-- Entity detector
+-- Detects entitys in a certain radius
+-- The radius can be changes by right-click (by default 6)
+
+local function make_formspec(meta)
+	meta:set_string("formspec", "size[9,5]" ..
+		"field[0.3,  0;9,2;scanname;Name (itemstring) of entity to scan for (empty for any):;${scanname}]"..
+		"field[0.3,1.5;4,2;digiline_channel;Digiline Channel (optional):;${digiline_channel}]"..
+		"field[0.3,3;2,2;radius;Detection radius:;${radius}]"..
+		"button_exit[3.5,3.5;2,3;;Save]")
+end
+
+local function object_detector_make_formspec(pos)
+	make_formspec(minetest.get_meta(pos))
+end
+
+local function object_detector_on_receive_fields(pos, formname, fields)
+	if not fields.scanname
+	or not fields.digiline_channel then
+		return
+	end
+
+	local meta = minetest.get_meta(pos)
+	meta:set_string("scanname", fields.scanname)
+	meta:set_string("digiline_channel", fields.digiline_channel)
+	local r = tonumber(fields.radius)
+	if r then
+		meta:set_int("radius", r)
+	end
+end
+
+-- returns true if entity was found, false if not
+local object_detector_scan = function (pos)
+	local meta = minetest.get_meta(pos)
+	local scanname = meta:get_string("scanname")
+	local scan_all = scanname == ""
+	local radius = meta:get_int("radius")
+	if radius == 0 then
+		radius = 6
+	end
+	for _,obj in pairs(minetest.get_objects_inside_radius(pos, radius)) do
+		if not obj:is_player() then
+			local isname = (obj:get_luaentity()).name
+			if isname
+			and (scan_all or isname == scanname) then -- entity with scanname found or not scanname specified
+				return true
+			end
+		end
+	end
+	return false
+end
+
+-- set entity name when receiving a digiline signal on a specific channel
+local object_detector_digiline = {
+	effector = {
+		action = function (pos, node, channel, msg)
+			local meta = minetest.get_meta(pos)
+			local active_channel = meta:get_string("digiline_channel")
+			if channel ~= active_channel then
+				return
+			end
+			meta:set_string("scanname", msg)
+			if meta:get_string("formspec") ~= "" then
+				make_formspec(meta)
+			end
+		end,
+	}
+}
+
+minetest.register_node("moremesecons_entity_detector:entity_detector_off", {
+	tiles = {"default_steel_block.png", "default_steel_block.png", "moremesecons_entity_detector_off.png"},
+	paramtype = "light",
+	walkable = true,
+	groups = {cracky=3},
+	description="Entity Detector",
+	mesecons = {receptor = {
+		state = mesecon.state.off,
+		rules = mesecon.rules.pplate
+	}},
+	on_construct = object_detector_make_formspec,
+	on_receive_fields = object_detector_on_receive_fields,
+	sounds = default.node_sound_stone_defaults(),
+	digiline = object_detector_digiline
+})
+
+minetest.register_node("moremesecons_entity_detector:entity_detector_on", {
+	tiles = {"default_steel_block.png", "default_steel_block.png", "moremesecons_entity_detector_on.png"},
+	paramtype = "light",
+	walkable = true,
+	groups = {cracky=3,not_in_creative_inventory=1},
+	drop = 'mesecons_detector:object_detector_off',
+	mesecons = {receptor = {
+		state = mesecon.state.on,
+		rules = mesecon.rules.pplate
+	}},
+	on_construct = object_detector_make_formspec,
+	on_receive_fields = object_detector_on_receive_fields,
+	sounds = default.node_sound_stone_defaults(),
+	digiline = object_detector_digiline
+})
+
+minetest.register_craft({
+	output = 'moremesecons_entity_detector:entity_detector_off',
+	recipe = {
+		{"mesecons_detector:object_detector_off"},
+		{"default:mese_crystal_fragment"}
+	}
+})
+
+minetest.register_abm({
+	nodenames = {"moremesecons_entity_detector:entity_detector_off"},
+	interval = 1.0,
+	chance = 1,
+	action = function(pos)
+		if object_detector_scan(pos) then
+			minetest.swap_node(pos, {name = "moremesecons_entity_detector:entity_detector_on"})
+			mesecon.receptor_on(pos, mesecon.rules.pplate)
+		end
+	end,
+})
+
+minetest.register_abm({
+	nodenames = {"moremesecons_entity_detector:entity_detector_on"},
+	interval = 1.0,
+	chance = 1,
+	action = function(pos)
+		if not object_detector_scan(pos) then
+			minetest.swap_node(pos, {name = "moremesecons_entity_detector:entity_detector_off"})
+			mesecon.receptor_off(pos, mesecon.rules.pplate)
+		end
+	end,
+})