Fix music player's sound management

If an operating music player was disconnected from the electrical network
or destroyed, it used to leave the music playing forever.  There was
also a glitch upon starting playing, as the music was started by the
form handler but then stopped when the run function realised it wasn't
receiving any power, because it hadn't demanded any yet.

diff --git a/technic/machines/LV/music_player.lua b/technic/machines/LV/music_player.lua
index f51d29d0e8fe33901ad3a3c6a125610acc252819..ba5daab4094680a5ffd95293ff326157658474cd 100644 (file)
--- a/technic/machines/LV/music_player.lua
+++ b/technic/machines/LV/music_player.lua
@@ -76,6 +76,15 @@ local run = function(pos, node)
        meta:set_int("LV_EU_demand", demand)
 end
 
+local function stop_player(pos, node)
+       local pos_hash = minetest.hash_node_position(pos)
+       local music_handle = music_handles[pos_hash]
+       if music_handle then
+               minetest.sound_stop(music_handle)
+               music_handles[pos_hash] = nil
+       end
+end
+
 minetest.register_node("technic:music_player", {
        description = S("%s Music Player"):format("LV"),
        tiles = {"technic_music_player_top.png", "technic_machine_bottom.png", "technic_music_player_side.png",
@@ -91,8 +100,6 @@ minetest.register_node("technic:music_player", {
        end,
        on_receive_fields = function(pos, formanme, fields, sender)
                local meta          = minetest.get_meta(pos)
-               local pos_hash      = minetest.hash_node_position(pos)
-               local music_handle  = music_handles[pos_hash]
                local current_track = meta:get_int("current_track")
                if fields.track1 then current_track = 1 end
                if fields.track2 then current_track = 2 end
@@ -120,22 +127,14 @@ minetest.register_node("technic:music_player", {
                                "button[6,4;1,2;stop;Stop]"..
                                "label[4,0;"..S("Current track %s")
                                        :format(current_track).."]")
-               if fields.play then
-                       if music_handle then
-                               minetest.sound_stop(music_handle)
-                       end
-                       music_handle = play_track(pos, current_track)
-                       meta:set_int("active", 1)
-               end
-               if fields.stop then
-                       meta:set_int("active", 0)
-                       if music_handle then
-                               minetest.sound_stop(music_handle)
-                       end
+               if fields.play or fields.stop then
+                       stop_player(pos)
+                       meta:set_int("active", fields.play and 1 or 0)
                end
-               music_handles[pos_hash] = music_handle
        end,
+       on_destruct = stop_player,
        technic_run = run,
+       technic_on_disable = stop_player,
 })
 
 technic.register_machine("LV", "technic:music_player", technic.receiver)