Add a distance limit to the entity detector (#32)

The distance limit can be configured with the `moremesecons_entity_detector.max_radius` setting.

An additional change prevents a crash if an object returned by `get_objects_inside_radius` is neither a valid player nor a luaentity. We don't know why this happens but it sometimes does.

moremesecons_entity_detector/init.lua

@@ -26,7 +26,8 @@ local function object_detector_on_receive_fields(pos, _, fields, player)
 	meta:set_string("digiline_channel", fields.digiline_channel)
 	local r = tonumber(fields.radius)
 	if r then
-		meta:set_int("radius", r)
+		local max_radius = moremesecons.setting("entity_detector", "max_radius", 16, 0)
+		meta:set_int("radius", math.min(r, max_radius))
 	end
 end
 
@@ -36,23 +37,19 @@ local object_detector_scan = function (pos)
 	local scanname = meta:get_string("scanname")
 	local scan_all = scanname == ""
 	local scan_names = scanname:split(',')
-	local radius = meta:get_int("radius")
-	if radius == 0 then
-		radius = 6
-	end
+	local max_radius = moremesecons.setting("entity_detector", "max_radius", 16, 0)
+	local radius = math.min(tonumber(meta:get("radius")) or 6, max_radius)
 	for _,obj in pairs(minetest.get_objects_inside_radius(pos, radius)) do
-		if not obj:is_player() then
-			local luaentity = obj:get_luaentity()
+		local luaentity = obj:get_luaentity()
+		if luaentity then
+			if scan_all then
+				return true
+			end
 			local isname = luaentity.name
-			if isname then
-				if scan_all then
+			for _, name in ipairs(scan_names) do
+				if isname == name or (isname == "__builtin:item" and luaentity.itemstring == name) then
 					return true
 				end
-				for _, name in ipairs(scan_names) do
-					if isname == name or (isname == "__builtin:item" and luaentity.itemstring == name) then
-						return true
-					end
-				end
 			end
 		end
 	end

settingtypes.txt

@@ -13,6 +13,10 @@ moremesecons_commandblock.authorized_commands (Authorized commands) string tell
 # Any value less than or equal to 0 will be changed to 1 and a NaN value will be changed to the default value
 moremesecons_commandblock.nearest_max_distance (Nearest player maximum distance) float 8
 
+[Entity Detector]
+
+moremesecons_entity_detector.max_radius (Maximum entity detector radius) float 16 0
+
 [Signal Jammer]
 
 # Jammer action range