fix: keep active sounds from restarting during movement

README.md

@@ -64,10 +64,11 @@ playback:
   leave-grace-ticks: 100
   blend-overlapping-zones: false
   follow-player: true
+  fade-volume-updates: false
   loop-restart-ticks: 2680
 ```
 
-When a selected zone remains selected, Ambient Audio Zone normally sends no new sound packet. In follow-player mode it re-emits only when the calculated fade changes materially, and it uses an entity-attached packet so the sound follows the player. Leaving starts a configurable grace timer; returning before it expires preserves the existing client playback instead of restarting it. `loop-restart-ticks` is a fallback for sounds whose resource-pack definition does not loop; set it to the exact sound length, while resource-pack `loop: true` remains the seamless option. Reloading or editing a zone intentionally replaces its active sound.
+When a selected zone remains selected, Ambient Audio Zone normally sends no new sound packet, so walking cannot restart or stack the audio. `fade-volume-updates` is disabled by default because Bukkit has no mutable-volume packet; enabling it approximates the fade by stopping and re-emitting the sound, which necessarily restarts it. For smooth native distance attenuation, disable `follow-player` and use a central `origin`. Leaving starts a configurable grace timer; returning before it expires preserves the existing client playback instead of restarting it. `loop-restart-ticks` is a fallback for sounds whose resource-pack definition does not loop; set it to the exact sound length, while resource-pack `loop: true` remains the seamless option. Reloading or editing a zone intentionally replaces its active sound.
 
 ## Resource-pack looping note
 

src/main/java/com/lexian/ambientaudio/service/PlaybackService.java

@@ -12,13 +12,13 @@ import java.util.stream.Collectors;
 public final class PlaybackService {
     private final JavaPlugin plugin; private final ZoneIndex index = new ZoneIndex();
     private final Map<UUID, Map<String, ActiveSound>> active = new HashMap<>();
-    private boolean blending; private boolean followPlayer; private long leaveGraceTicks, loopRestartTicks; private int taskId = -1;
+    private boolean blending; private boolean followPlayer, fadeVolumeUpdates; private long leaveGraceTicks, loopRestartTicks; private int taskId = -1;
 
     public PlaybackService(JavaPlugin plugin) { this.plugin = plugin; }
     public void configure(Collection<AudioZone> zones, int intervalTicks, long leaveGraceTicks, boolean blending,
-                           boolean followPlayer, long loopRestartTicks) {
+                           boolean followPlayer, boolean fadeVolumeUpdates, long loopRestartTicks) {
         stopAll(); index.rebuild(zones); this.blending = blending; this.leaveGraceTicks = leaveGraceTicks;
-        this.followPlayer = followPlayer; this.loopRestartTicks = loopRestartTicks;
+        this.followPlayer = followPlayer; this.fadeVolumeUpdates = fadeVolumeUpdates; this.loopRestartTicks = loopRestartTicks;
         if (taskId != -1) Bukkit.getScheduler().cancelTask(taskId);
         taskId = Bukkit.getScheduler().scheduleSyncRepeatingTask(plugin, this::tick, intervalTicks, intervalTicks);
     }
@@ -35,21 +35,21 @@ public final class PlaybackService {
             float volume = volumeFor(zone, player);
             if (sound == null) {
                 play(player, zone, volume);
-                current.put(zone.normalizedName(), new ActiveSound(zone, Long.MAX_VALUE, now, volume));
+                current.put(zone.normalizedName(), new ActiveSound(zone, Long.MAX_VALUE, now, now, volume));
             } else if (zone.loop() && loopRestartTicks > 0 && now - sound.startedAtTick() >= loopRestartTicks) {
                 play(player, zone, volume);
-                current.put(zone.normalizedName(), new ActiveSound(zone, Long.MAX_VALUE, now, volume));
-            } else if (followPlayer && Math.abs(sound.volume() - volume) >= 0.05f) {
-                // A sound packet has no mutable volume. Re-emit only when the fade changed materially;
-                // inside the zone the packet remains attached to the player and is not restarted.
+                current.put(zone.normalizedName(), new ActiveSound(zone, Long.MAX_VALUE, now, now, volume));
+            } else if (followPlayer && fadeVolumeUpdates && now - sound.lastPacketTick() >= 40 && Math.abs(sound.volume() - volume) >= 0.10f) {
+                // Bukkit has no volume-update packet. Rate-limit fade packets and stop the previous
+                // packet first; otherwise repeated entity sound packets overlap on the client.
                 play(player, zone, volume);
-                current.put(zone.normalizedName(), new ActiveSound(zone, Long.MAX_VALUE, sound.startedAtTick(), volume));
+                current.put(zone.normalizedName(), new ActiveSound(zone, Long.MAX_VALUE, sound.startedAtTick(), now, volume));
             }
         }
         for (Iterator<Map.Entry<String, ActiveSound>> it = current.entrySet().iterator(); it.hasNext();) {
             Map.Entry<String, ActiveSound> entry = it.next(); ActiveSound sound = entry.getValue();
-            if (desired.contains(entry.getKey())) { entry.setValue(new ActiveSound(sound.zone(), Long.MAX_VALUE, sound.startedAtTick(), sound.volume())); continue; }
-            if (sound.stopAtTick() == Long.MAX_VALUE) { entry.setValue(new ActiveSound(sound.zone(), now + leaveGraceTicks, sound.startedAtTick(), sound.volume())); continue; }
+            if (desired.contains(entry.getKey())) { entry.setValue(new ActiveSound(sound.zone(), Long.MAX_VALUE, sound.startedAtTick(), sound.lastPacketTick(), sound.volume())); continue; }
+            if (sound.stopAtTick() == Long.MAX_VALUE) { entry.setValue(new ActiveSound(sound.zone(), now + leaveGraceTicks, sound.startedAtTick(), sound.lastPacketTick(), sound.volume())); continue; }
             if (now >= sound.stopAtTick()) { player.stopSound(sound.zone().sound(), sound.zone().category()); it.remove(); }
         }
         if (current.isEmpty()) active.remove(player.getUniqueId());
@@ -63,15 +63,18 @@ public final class PlaybackService {
         } active.clear();
     }
     private void play(Player player, AudioZone zone, float volume) {
+        // A sound event is not a handle. Stop the matching event before re-emitting it so
+        // fade updates and loop restarts cannot layer copies of the same sound.
+        player.stopSound(zone.sound(), zone.category());
         if (followPlayer) player.playSound(player, zone.sound(), zone.category(), volume, zone.pitch());
         else player.playSound(zone.originLocation(player.getWorld()), zone.sound(), zone.category(), zone.volume(), zone.pitch());
     }
     private float volumeFor(AudioZone zone, Player player) {
-        if (!followPlayer) return zone.volume();
+        if (!followPlayer || !fadeVolumeUpdates) return zone.volume();
         double fade = zone.fadeDistance();
         double distance = Math.sqrt(zone.distanceToAudibleAreaSquared(player.getLocation()));
         double multiplier = fade == 0 ? (distance == 0 ? 1 : 0) : Math.max(0, 1 - distance / fade);
         return (float) Math.max(0.001, zone.volume() * multiplier);
     }
-    private record ActiveSound(AudioZone zone, long stopAtTick, long startedAtTick, float volume) { }
+    private record ActiveSound(AudioZone zone, long stopAtTick, long startedAtTick, long lastPacketTick, float volume) { }
 }

src/main/java/com/lexian/ambientaudio/service/ZoneService.java

@@ -18,5 +18,5 @@ public final class ZoneService {
     public AudioZone get(String name) { return zones.get(name.toLowerCase(Locale.ROOT)); }
     public void put(AudioZone zone) throws IOException { zones.put(zone.normalizedName(), zone); store.save(zones.values()); refreshPlayback(); }
     public AudioZone remove(String name) throws IOException { AudioZone removed = zones.remove(name.toLowerCase(Locale.ROOT)); if (removed != null) { store.save(zones.values()); refreshPlayback(); } return removed; }
-    private void refreshPlayback() { FileConfiguration c = plugin.getConfig(); playback.configure(zones.values(), Math.max(1, c.getInt("playback.check-interval-ticks", 10)), Math.max(0, c.getLong("playback.leave-grace-ticks", 100)), c.getBoolean("playback.blend-overlapping-zones", false), c.getBoolean("playback.follow-player", true), Math.max(0, c.getLong("playback.loop-restart-ticks", 2680))); }
+    private void refreshPlayback() { FileConfiguration c = plugin.getConfig(); playback.configure(zones.values(), Math.max(1, c.getInt("playback.check-interval-ticks", 10)), Math.max(0, c.getLong("playback.leave-grace-ticks", 100)), c.getBoolean("playback.blend-overlapping-zones", false), c.getBoolean("playback.follow-player", true), c.getBoolean("playback.fade-volume-updates", false), Math.max(0, c.getLong("playback.loop-restart-ticks", 2680))); }
 }

src/main/resources/config.yml

@@ -6,6 +6,9 @@ playback:
   blend-overlapping-zones: false
   # Entity-attached sounds follow each player instead of remaining at origin.
   follow-player: true
+  # Disabled by default: Bukkit has no mutable-volume packet, so enabling this
+  # necessarily restarts the sound when the calculated volume changes.
+  fade-volume-updates: false
   # Fallback replay interval for loop: true sounds. 2680 ticks is 134 seconds.
   # Set to the actual length of custom sounds; resource-pack loop=true is preferred.
   loop-restart-ticks: 2680