do not show unset position

init.lua

@@ -14,6 +14,7 @@ local compass_range = 180
 
 
 local function set_compass_meta_label(meta, label)
+    meta:set_string("description", string.format("Waypoint compass to \"%s\"", label))
     meta:set_string("waypoint_compass:label", label)
 end
 
@@ -31,7 +32,13 @@ end
 
 
 local function get_compass_meta_pos(meta)
-    return minetest.deserialize(meta:get_string("waypoint_compass:position"))
+    local pos_str = meta:get_string("waypoint_compass:position")
+    if pos_str == "" then
+        -- FIXME This is probably bad.
+        return nil
+    else
+        return minetest.deserialize(meta:get_string("waypoint_compass:position"))
+    end
 end
 
 
@@ -110,6 +117,11 @@ end
 
 local function show_hud_waypoint(player, compass_item_meta)
     local player_name = player:get_player_name()
+    local waypoint_pos = get_compass_meta_pos(compass_item_meta)
+    if waypoint_pos == nil then
+        -- do not show unset compass position
+        return
+    end
     -- Show this waypoint
     local waypoint_name = get_compass_meta_label(compass_item_meta)
     local waypoint_color = get_compass_meta_color(compass_item_meta)
@@ -119,14 +131,14 @@ local function show_hud_waypoint(player, compass_item_meta)
             text = "m",
             precision= compass_precision,
             number = waypoint_color,
-            world_pos = get_compass_meta_pos(compass_item_meta),
+            world_pos = waypoint_pos,
     })
     -- store HUD elemnt id to remove it later
     if not player_waypoints[player_name] then
         player_waypoints[player_name] = {}
     end
     --print("hud_id add", hud_id)
-    player_waypoints[player_name].pos = get_compass_meta_pos(compass_item_meta)
+    player_waypoints[player_name].pos = waypoint_pos
     player_waypoints[player_name].hud_id = hud_id
 end
 
@@ -143,8 +155,8 @@ local function update_hud_waypoint(player, itemstack, force)
         local meta = itemstack:get_meta()
         local waypoint_pos = get_compass_meta_pos(meta)
         -- remove different waypoint if it exists
-        if player_waypoints[player_name] or force and
+        if player_waypoints[player_name] and waypoint_pos and
-            (player_waypoints[player_name].pos ~= waypoint_pos) then
+            ((player_waypoints[player_name].pos ~= waypoint_pos) or force) then
             hide_hud_waypoint(player)
         end
         -- show new waypoint
@@ -194,6 +206,7 @@ local function coords_from_string(str)
     return {x = tmp[1], y = tmp[2], z = tmp[3]}
 end
 
+
 local compass_dialog_context = {}
 
 local function show_basic_dialog(itemstack, player)
@@ -224,15 +237,14 @@ local function compass_use_callback(itemstack, user, pointed_thing)
     end
     local meta = itemstack:get_meta()
     local owner = get_compass_meta_owner(meta)
-    print("owner", owner)
+    local player_name = user:get_player_name()
     if owner == "" then
         -- set first user as owner
-        print("set owner", user:get_player_name())
+        set_compass_meta_owner(meta, player_name)
-        set_compass_meta_owner(meta, user:get_player_name())
+    elseif owner ~= player_name then
-    elseif owner ~= user:get_player_name() then
         -- already has owner
         -- TODO show message "You are not the owner" (or maybe limit editing to color change?)
-        print("You are not the owner. Owner is " .. owner)
+        minetest.chat_send_player(player_name, "You are not the owner of this compass. Owner is " .. owner .. ".")
         return itemstack
     end
     if user:get_player_control()["sneak"] then
@@ -260,13 +272,16 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
         local compass_item = compass_dialog_context[player:get_player_name()]
         if not compass_item then
             -- should not happen normally
-            minetest.log("error","[MOD] waypoint_compass: " .. player:get_player_name() .. " Closed compass dialog without opening it?")
+            minetest.log("error","[MOD] waypoint_compass: " ..
+                         player:get_player_name() ..
+                         " Closed compass dialog without opening it?")
             return
         end
         local meta = compass_item:get_meta()
         
         local color = tonumber("0x"..fields.color, 16)
         if color then
+            color = math.max(math.min(color, 0xFFFFFF), 0x0) -- for some reason seems to work fine without this
             set_compass_meta_color(meta, color)
         end
         
@@ -281,7 +296,9 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
         local success = player:set_wielded_item(compass_item)
         if not success then
             -- no idea why this can happen
-            minetest.log("error","[MOD] waypoint_compass: " .. player:get_player_name() .. " Failed to swap compass after editing it")
+            minetest.log("error","[MOD] waypoint_compass: " ..
+                         player:get_player_name() ..
+                         " Failed to swap compass after editing it")
         end
         -- assume dialog is closed and reset context
         compass_dialog_context[player:get_player_name()] = nil
@@ -293,7 +310,7 @@ end)
 minetest.register_tool(
     "waypoint_compass:compass", {
         description = "Waypoint compass\n(sneak+place to set point)",
-        short_description = "Waypoint compass",
+        --short_description = "Waypoint compass",
         inventory_image = "Waypoint_compass_inventory_image.png",
         wield_scale = {x = 0.5, y = 0.5, z = 0.5},
         range = 2.0, -- TODO what's the good range?