Improve sound experience

- Zip sounds are more pronounced
- Scatter zip sounds along path for
  3rd party observers
- Add subtle hum to waiting ziprunes.

init.lua

@@ -3,8 +3,8 @@ local math, minetest, nodecore, pairs, rawset, string, table, tonumber,
       vector
     = math, minetest, nodecore, pairs, rawset, string, table, tonumber,
       vector
-local math_abs, string_format, table_remove, table_sort
-    = math.abs, string.format, table.remove, table.sort
+local math_abs, math_random, string_format, table_remove, table_sort
+    = math.abs, math.random, string.format, table.remove, table.sort
 -- LUALOCALS > ---------------------------------------------------------
 
 local modname = minetest.get_current_modname()
@@ -133,15 +133,16 @@ local function dsqr(a, b)
 	return vector.dot(v, v)
 end
 
-local function playercheck(player)
-	local vel = player:get_player_velocity()
-	if vector.dot(vel, vel) > 0.1 then return end
-
+local function playercheck(player, stepdata)
 	local ctl = player:get_player_control()
 	if ctl.sneak or ctl.jump or ctl.up or ctl.down or ctl.left or ctl.right then return end
 
 	local data = zipdata_get(player)
 	if not data.pos then return end
+	stepdata.properties.makes_footstep_sound = false
+
+	local vel = player:get_player_velocity()
+	if vector.dot(vel, vel) > 0.1 then return end
 
 	local pos = vector.round(player:get_pos())
 	if not inrange(pos, data.pos) then
@@ -176,11 +177,18 @@ local function playercheck(player)
 			nodecore.log("action", string_format("%s: %s zips from %s to %s",
 					modname, player:get_player_name(), minetest.pos_to_string(pos),
 					minetest.pos_to_string(hit)))
+			local backdir = vector.direction(hit, pos)
+			for i = 0, vector.distance(pos, hit), 4 do
+				local spos = vector.add(hit, vector.multiply(backdir, i))
+				spos.x = spos.x + math_random() - 0.5
+				spos.y = spos.y + math_random() - 0.5
+				spos.z = spos.z + math_random() - 0.5
+				nodecore.sound_play(modname .. "_zip", {pos = spos})
+			end
 			data.oldpos = appendpos(data.oldpos or {}, data.pos)
 			data.pos = hit
 			zipdata_set(player, data)
 			player:set_pos({x = hit.x, y = hit.y - 0.49, z = hit.z})
-			nodecore.sound_play(modname .. "_zip", {pos = hit})
 			return sparkly(p, hit)
 		end
 	end
@@ -188,11 +196,11 @@ local function playercheck(player)
 	energized(pos)
 end
 
-minetest.register_globalstep(function()
-		for _, player in pairs(minetest.get_connected_players()) do
-			playercheck(player)
-		end
-	end)
+nodecore.register_playerstep({
+		label = "ziprune check",
+		priority = -100,
+		action = playercheck
+	})
 
 local powernodes = {}
 for i = minpower, 8 do powernodes["nc_lux:cobble" .. i] = true end
@@ -230,6 +238,7 @@ nodecore.register_dnt({
 			if not isziprune(pos, node) then return end
 
 			nodecore.dnt_set(pos, modname)
+			nodecore.sound_play(modname .. "_hum", {pos = pos, gain = 0.25})
 			minetest.add_particlespawner({
 					amount = 20,
 					time = 1,