[BUGFIX] Chart Editor/Gameplay: Fixes countdown and audio artifacts with offsets

source/funkin/Conductor.hx

@@ -397,9 +397,12 @@ class Conductor
    */
   public function update(?songPos:Float, applyOffsets:Bool = true, forceDispatch:Bool = false)
   {
+    var currentTime:Float = (FlxG.sound.music != null) ? FlxG.sound.music.time : 0.0;
+    var currentLength:Float = (FlxG.sound.music != null) ? FlxG.sound.music.length : 0.0;
+
     if (songPos == null)
     {
-      songPos = (FlxG.sound.music != null) ? FlxG.sound.music.time : 0.0;
+      songPos = currentTime;
     }
 
     // Take into account instrumental and file format song offsets.
@@ -409,8 +412,17 @@ class Conductor
     var oldBeat:Float = this.currentBeat;
     var oldStep:Float = this.currentStep;
 
+    // If the song is playing, limit the song position to the length of the song or beginning of the song.
+    if (FlxG.sound.music != null && FlxG.sound.music.playing)
+    {
+      this.songPosition = Math.min(currentLength, Math.max(0, songPos));
+    }
+    else
+    {
+      this.songPosition = songPos;
+    }
+
     // Set the song position we are at (for purposes of calculating note positions, etc).
-    this.songPosition = songPos;
 
     currentTimeChange = timeChanges[0];
     if (this.songPosition > 0.0)
@@ -430,7 +442,8 @@ class Conductor
     else if (currentTimeChange != null && this.songPosition > 0.0)
     {
       // roundDecimal prevents representing 8 as 7.9999999
-      this.currentStepTime = FlxMath.roundDecimal((currentTimeChange.beatTime * Constants.STEPS_PER_BEAT) + (this.songPosition - currentTimeChange.timeStamp) / stepLengthMs, 6);
+      this.currentStepTime = FlxMath.roundDecimal((currentTimeChange.beatTime * Constants.STEPS_PER_BEAT)
+        + (this.songPosition - currentTimeChange.timeStamp) / stepLengthMs, 6);
       this.currentBeatTime = currentStepTime / Constants.STEPS_PER_BEAT;
       this.currentMeasureTime = currentStepTime / stepsPerMeasure;
       this.currentStep = Math.floor(currentStepTime);

source/funkin/play/PlayState.hx

@@ -687,7 +687,11 @@ class PlayState extends MusicBeatSubState
     }
 
     Conductor.instance.mapTimeChanges(currentChart.timeChanges);
-    Conductor.instance.update((Conductor.instance.beatLengthMs * -5) + startTimestamp);
+    var pre:Float = (Conductor.instance.beatLengthMs * -5) + startTimestamp;
+
+    trace('Attempting to start at ' + pre);
+
+    Conductor.instance.update(pre);
 
     // The song is now loaded. We can continue to initialize the play state.
     initCameras();
@@ -915,7 +919,11 @@ class PlayState extends MusicBeatSubState
       {
         // Do NOT apply offsets at this point, because they already got applied the previous frame!
         Conductor.instance.update(Conductor.instance.songPosition + elapsed * 1000, false);
-        if (Conductor.instance.songPosition >= (startTimestamp)) startSong();
+        if (Conductor.instance.songPosition >= (startTimestamp + Conductor.instance.instrumentalOffset))
+        {
+          trace("started song at " + Conductor.instance.songPosition);
+          startSong();
+        }
       }
     }
     else
@@ -1391,15 +1399,18 @@ class PlayState extends MusicBeatSubState
       // activeNotes.sort(SortUtil.byStrumtime, FlxSort.DESCENDING);
     }
 
-    if (!startingSong
-      && FlxG.sound.music != null
-      && (Math.abs(FlxG.sound.music.time - (Conductor.instance.songPosition + Conductor.instance.instrumentalOffset)) > 100
-        || Math.abs(vocals.checkSyncError(Conductor.instance.songPosition + Conductor.instance.instrumentalOffset)) > 100))
+    if (FlxG.sound.music != null)
     {
-      trace("VOCALS NEED RESYNC");
-      if (vocals != null) trace(vocals.checkSyncError(Conductor.instance.songPosition + Conductor.instance.instrumentalOffset));
-      trace(FlxG.sound.music.time - (Conductor.instance.songPosition + Conductor.instance.instrumentalOffset));
-      resyncVocals();
+      var correctSync:Float = Math.min(FlxG.sound.music.length, Math.max(0, Conductor.instance.songPosition - Conductor.instance.instrumentalOffset));
+
+      if (!startingSong && (Math.abs(FlxG.sound.music.time - correctSync) > 5 || Math.abs(vocals.checkSyncError(correctSync)) > 5))
+      {
+        trace("VOCALS NEED RESYNC");
+        if (vocals != null) trace(vocals.checkSyncError(correctSync));
+        trace(FlxG.sound.music.time);
+        trace(correctSync);
+        resyncVocals();
+      }
     }
 
     // Only bop camera if zoom level is below 135%
@@ -1968,6 +1979,7 @@ class PlayState extends MusicBeatSubState
     vocals.play();
     vocals.volume = 1.0;
     vocals.pitch = playbackRate;
+    vocals.time = startTimestamp;
     resyncVocals();
 
     #if FEATURE_DISCORD_RPC
@@ -1993,7 +2005,9 @@ class PlayState extends MusicBeatSubState
 
     // Skip this if the music is paused (GameOver, Pause menu, start-of-song offset, etc.)
     if (!(FlxG.sound.music?.playing ?? false)) return;
-    var timeToPlayAt:Float = Conductor.instance.songPosition - Conductor.instance.instrumentalOffset;
+
+    var timeToPlayAt:Float = Math.min(FlxG.sound.music.length, Math.max(0, Conductor.instance.songPosition - Conductor.instance.instrumentalOffset));
+    trace('Resyncing vocals to ${timeToPlayAt}');
     FlxG.sound.music.pause();
     vocals.pause();