add a location logger

this is handy in my more complicated mapgens to find examples of things generated "in the wild".

init.lua

@@ -15,7 +15,7 @@ dofile(MP.."/lines.lua")
 dofile(MP.."/place_schematic.lua")
 dofile(MP.."/noise_manager.lua")
 dofile(MP.."/metrics.lua")
-
+dofile(MP.."/log_location.lua")
 
 local map_data = {}
 local map_param2_data = {}

log_location.lua

@@ -0,0 +1,108 @@
+if not minetest.settings:get_bool("mapgen_helper_log_locations", false) then
+	mapgen_helper.log_first_location = function()
+		return
+	end
+	return
+end
+
+mapgen_helper.log_location_enabled = true
+
+local worldpath = minetest.get_worldpath()
+local locations = {}
+
+local save_data = function()
+	local file = io.open(worldpath.."/mapgen_helper_test_locations.json", "w")
+	if file then
+		local data = {}
+		data.locations = locations
+		file:write(minetest.serialize(data))
+		file:close()
+	end
+end
+
+local read_data = function()
+	local file = io.open(worldpath.."/mapgen_helper_test_locations.json", "r")
+	if file then
+		local data = minetest.deserialize(file:read("*all"))
+		locations = data.locations or {}
+		file:close()
+	else
+		locations = {}
+	end
+end
+read_data()
+
+mapgen_helper.log_first_location = function(name, pos, desc, notes)
+	if not locations[name] then
+		locations[name] = {pos=pos, desc=desc, notes=notes}
+		minetest.log("info", "[mapgen_helper] recorded location " .. name .. " at " .. minetest.pos_to_string(pos) .. " with desc '" .. (desc or "") .. "'")
+		save_data()
+	end
+end
+
+minetest.register_chatcommand("mapgen_helper_loc", {
+	params = "[location name]",
+	description = "sends the player to the named test location, or lists recorded locations if no parameter is given",
+	privs = {server=true},
+	func = function(name, param)
+		if not param or param == "" then
+			minetest.chat_send_all("test locations available:")
+			local names = {}
+			for name, loc in pairs(locations) do
+				table.insert(names, name)
+			end
+			table.sort(names)			
+			for number, name in ipairs(names) do
+				minetest.chat_send_all("\t"..name .. " - " .. (locations[name].desc or ""))
+			end
+			return
+		end
+		local loc = locations[param]
+		if not loc then
+			minetest.chat_send_all("test location " .. param .. " not found")
+			return
+		end
+		local player = minetest.get_player_by_name(name)
+		player:set_pos(loc.pos)
+		if loc.notes then
+			minetest.chat_send_player(name, loc.notes)
+		end
+	end,
+})
+
+local tour_index = 0
+minetest.register_chatcommand("mapgen_helper_tour", {
+	params = "<next|prev>",
+	description = "cycles through the various recorded mapgen test locations, forward or backward",
+	privs = {server=true},
+	func = function(name, param)
+		local names = {}
+		for name, loc in pairs(locations) do
+			table.insert(names, name)
+		end
+		table.sort(names)			
+		if param == "prev" then
+			tour_index = tour_index - 1
+			if tour_index < 1 then
+				tour_index = #names
+			end
+		else
+			tour_index = tour_index + 1
+			if tour_index > #names then
+				tour_index = 1
+			end
+		end
+		
+		local loc = locations[names[tour_index]]
+		local player = minetest.get_player_by_name(name)
+		player:set_pos(loc.pos)
+		minetest.chat_send_player(name, "Teleport to test location " .. names[tour_index])
+		if loc.notes then
+			minetest.chat_send_player(name, loc.notes)
+		end
+	end
+})
+
+minetest.register_on_shutdown(function()
+	save_data()
+end)

metrics.lua

@@ -1,5 +1,3 @@
-local worldpath = minetest.get_worldpath()
-
 if not minetest.settings:get_bool("mapgen_helper_record_time", false) then
 	mapgen_helper.record_time = function()
 		return
@@ -7,6 +5,8 @@ if not minetest.settings:get_bool("mapgen_helper_record_time", false) then
 	return
 end
 
+local worldpath = minetest.get_worldpath()
+
 local persist = minetest.settings:get_bool("mapgen_helper_persist_recorded_time", false)
 local filename = "mapgen_helper_metrics.lua"
 local filename_old = "mapgen_helper_metrics_old.lua"

settingtypes.txt

@@ -1,3 +1,4 @@
 mapgen_helper_record_time (Enable time-taken logging) bool false
 mapgen_helper_persist_recorded_time (Persist time-taken logging between server sessions) bool false
-mapgen_helper_record_time_resolution (Resolution of time-taken histogram) float 0.1
+mapgen_helper_record_time_resolution (Resolution of time-taken histogram) float 0.1
+mapgen_helper_log_locations (Enable location logging) bool false