use an entity to show the protected area (#1)

(copied from Zeg9's mod)

init.lua

@@ -6,6 +6,15 @@ local function red(str)
 	return minetest.colorize("#FF5555",str)
 end
 
+local radius = minetest.setting_get("areasprotector_radius") or 8
+
+local function remove_display(pos)
+	local objs = minetest.get_objects_inside_radius(pos, 0.5)
+	for _,o in pairs(objs) do
+		o:remove()
+	end
+end
+
 minetest.register_node("areasprotector:protector",{
 	description = "Protector Block",
 	groups = {cracky=1},
@@ -14,8 +23,13 @@ minetest.register_node("areasprotector:protector",{
 		"default_steel_block.png",
 		"default_steel_block.png^areasprotector_protector.png"
 	},
+	paramtype = "light",
+	drawtype = "nodebox",
+	node_box = {
+		type = "fixed",
+		fixed = { -0.5, -0.5, -0.5, 0.5, 0.5, 0.5 },
+	},
 	on_place = function(itemstack,player,pointed)
-		local radius = minetest.setting_get("areasprotector_radius") or 8
 		local pos = pointed.above
 		local pos1 = vector.add(pos,vector.new(radius,radius,radius))
 		local pos2 = vector.add(pos,vector.new(-1*radius,-1*radius,-1*radius))
@@ -49,6 +63,66 @@ minetest.register_node("areasprotector:protector",{
 			areas:save()
 		end
 	end,
+	on_punch = function(pos, node, puncher)
+		local objs = minetest.get_objects_inside_radius(pos,.5) -- a radius of .5 since the entity serialization seems to be not that precise
+		local removed = false
+		for _, o in pairs(objs) do
+			if (not o:is_player()) and o:get_luaentity().name == "areasprotector:display" then
+				o:remove()
+				removed = true
+			end
+		end
+		if not removed then -- nothing was removed: there wasn't the entity
+			minetest.add_entity(pos, "areasprotector:display")
+			minetest.after(4, remove_display, pos)
+		end
+	end
+})
+
+-- entities code below (and above) mostly copied-pasted from Zeg9's protector mod
+
+minetest.register_entity("areasprotector:display", {
+	physical = false,
+	collisionbox = {0,0,0,0,0,0},
+	visual = "wielditem",
+	visual_size = {x=1.0/1.5,y=1.0/1.5}, -- wielditem seems to be scaled to 1.5 times original node size
+	textures = {"areasprotector:display_node"},
+	on_step = function(self, dtime)
+		if minetest.get_node(self.object:getpos()).name ~= "areasprotector:protector" then
+			self.object:remove()
+			return
+		end
+	end,
+})
+
+local nb_radius = radius + 0.55
+
+minetest.register_node("areasprotector:display_node", {
+	tiles = {"areasprotector_display.png"},
+	walkable = false,
+	drawtype = "nodebox",
+	node_box = {
+		type = "fixed",
+		fixed = {
+			-- sides
+			{ -nb_radius, -nb_radius, -nb_radius, -nb_radius,  nb_radius,  nb_radius },
+			{ -nb_radius, -nb_radius,  nb_radius,  nb_radius,  nb_radius,  nb_radius },
+			{  nb_radius, -nb_radius, -nb_radius,  nb_radius,  nb_radius,  nb_radius },
+			{ -nb_radius, -nb_radius, -nb_radius,  nb_radius,  nb_radius, -nb_radius },
+			-- top
+			{ -nb_radius,  nb_radius, -nb_radius,  nb_radius,  nb_radius,  nb_radius },
+			-- bottom
+			{ -nb_radius, -nb_radius, -nb_radius,  nb_radius, -nb_radius,  nb_radius },
+			-- middle (surround protector)
+			{-.55,-.55,-.55, .55,.55,.55},
+		},
+	},
+	selection_box = {
+		type = "regular",
+	},
+	paramtype = "light",
+	groups = {dig_immediate=3,not_in_creative_inventory=1},
+	drop = "",
 })
 
 minetest.register_craft({