Add setting for update frequency of handheld maps

mods/ITEMS/mcl_maps/init.lua

@@ -1,4 +1,6 @@
-mcl_maps = {}
+mcl_maps = {
+	map_update_fps = tonumber(minetest.settings:get("mcl_maps_map_update_fps")) or 15
+}
 
 local modname = minetest.get_current_modname()
 local modpath = minetest.get_modpath(modname)
@@ -473,7 +475,14 @@ function mcl_maps.make_banner_overlay(banners, minp, maxp, border)
 	return texture
 end
 
+local time_since_last_frame = 0
+
 minetest.register_globalstep(function(dtime)
+	time_since_last_frame = time_since_last_frame + dtime
+	if time_since_last_frame < ( 1 / mcl_maps.map_update_fps ) then
+		return
+	end
+	time_since_last_frame = 0
 	for _, player in pairs(get_connected_players()) do
 		local wield = player:get_wielded_item()
 		local texture = mcl_maps.load_map_item(wield)

settingtypes.txt

@@ -102,6 +102,9 @@ animated_chests (Animated chests) bool true
 # Whether to preview the player in inventory in 3D (requires Minetest 5.4)
 3d_player_preview (3D Player preview) bool true
 
+# How often the handheld map is updated per second
+mcl_maps_map_update_fps (Map Update FPS) int 15 0 60
+
 [Experimental]
 # Whether ice is translucent. If disabled, ice is fully opaque.
 #