diff --git a/init.lua b/init.lua
index ffaf59d..adf6b0e 100644
--- a/init.lua
+++ b/init.lua
@@ -1,10 +1,10 @@
-local update_interval = 1.31415
-local compass_precision = 10 -- set to 1 to show whole number or 10 for 1 decimal
-local default_waypoint_color = 0xFFFFFF
-local target_above = false -- place waypoint inside the block or above it
-local point_to_objects = false -- unimplemented
-local point_to_liquids = true
-local compass_range = 180
+local UPDATE_INTERVAL = 1.31415
+local COMPASS_PRECISION = 10 -- set to 1 to show whole number or 10 for 1 decimal
+local DEFAULT_WAYPOINT_COLOR = 0xFFFFFF
+local TARGET_ABOVE = false -- place waypoint inside the block or above it
+local POINT_TO_OBJECTS = false -- unimplemented
+local POINT_TO_LIQUIDS = true
+local COMPASS_RANGE = 180
 
 
 -- internal mod state
@@ -51,7 +51,7 @@ local function get_compass_meta_color(meta)
     if color > 0 then
         return color
     else
-        return default_waypoint_color
+        return DEFAULT_WAYPOINT_COLOR
     end
 end
 
@@ -78,7 +78,7 @@ end
 
 local function set_waypoint_at_pointed_place(itemstack, pointed_thing)
     if pointed_thing and pointed_thing.type == "node" then
-        local pointed_pos = target_above and pointed_thing.above or pointed_thing.under
+        local pointed_pos = TARGET_ABOVE and pointed_thing.above or pointed_thing.under
         local meta = itemstack:get_meta()
         meta:set_string("description", string.format("Waypoint compass %s", minetest.pos_to_string(pointed_pos)))
         set_compass_meta_pos(meta, pointed_pos)
@@ -96,7 +96,7 @@ local function raycast_crosshair(player, range)
     local p_eye_height = player:get_properties().eye_height
     local p_eye_pos = { x = p_pos.x, y = p_pos.y + p_eye_height, z = p_pos.z }
     local to = vector.add(p_eye_pos, vector.multiply(player:get_look_dir(), range))
-    local ray = minetest.raycast(p_eye_pos, to, point_to_objects, point_to_liquids)
+    local ray = minetest.raycast(p_eye_pos, to, POINT_TO_OBJECTS, POINT_TO_LIQUIDS)
     local pointed_thing = ray:next()
     return pointed_thing
     -- while pointed_thing do
@@ -128,7 +128,7 @@ local function show_hud_waypoint(player, compass_item_meta)
             hud_elem_type = "waypoint",
             name = waypoint_name,
             text = "m",
-            precision= compass_precision,
+            precision= COMPASS_PRECISION,
             number = waypoint_color,
             world_pos = waypoint_pos,
     })
@@ -177,7 +177,7 @@ end
 local timer = 0
 minetest.register_globalstep(function(dtime)
         timer = timer + dtime
-        if timer > update_interval then
+        if timer > UPDATE_INTERVAL then
             for _,player in pairs(minetest.get_connected_players()) do
                 local itemstack = player:get_wielded_item()
                 update_hud_waypoint(player, itemstack)
@@ -260,7 +260,7 @@ local function compass_use_callback(itemstack, user, pointed_thing)
     if user:get_player_control()["sneak"] then
         if pointed_thing.type == "nothing" then
             if user and user:is_player() then
-                pointed_thing = raycast_crosshair(user, compass_range)
+                pointed_thing = raycast_crosshair(user, COMPASS_RANGE)
             end
         end
         set_waypoint_at_pointed_place(itemstack, pointed_thing)