Alternative hotbar approach

We still change the background, but only depend
on the state of the slot, not on wield index.  Go
back to a traditional slot selection ring for the
selection index.

Slot backgrounds are a little bolder normally, and
when broken, especially bold around the broken
areas.

The selection ring itself is broken so that the
gaps in broken slots are still "open" to the outside
when the selection ring is in place.

mods/nc_player_hud/hotbar.lua

@@ -18,13 +18,14 @@ nodecore.register_playerstep({
 			for i = 1, hotbar_slots do
 				local stack = inv:get_stack("main", i)
 				local def = stack and (not stack:is_empty()) and stack:get_definition()
-				local suff = (i == player:get_wield_index()) and "_sel" or "_slot"
+				local suff = "_sel"
 				if def and def.hotbar_type then
 					suff = suff .. "_" .. def.hotbar_type
 				end
 				bar = bar .. ":" .. (i * bar_scale - bar_scale + bar_margin)
 				.. "," .. bar_margin .. "=" .. modname .. suff
 				.. ".png\\^[resize\\:" .. bar_scale .. "x" .. bar_scale
+				.. "\\^[opacity\\:192"
 			end
 
 			if data.slots ~= hotbar_slots then