Resolved lag issues caused by creating too many notes in the pool.

source/funkin/ui/debug/charting/ChartEditorEventSprite.hx

@@ -146,7 +146,7 @@ class ChartEditorEventSprite extends FlxSprite
   /**
    * Return whether this event is currently visible.
    */
-  public function isNoteVisible(viewAreaBottom:Float, viewAreaTop:Float):Bool
+  public function isEventVisible(viewAreaBottom:Float, viewAreaTop:Float):Bool
   {
     // True if the note is above the view area.
     var aboveViewArea = (this.y + this.height < viewAreaTop);
@@ -160,7 +160,7 @@ class ChartEditorEventSprite extends FlxSprite
   /**
    * Return whether an event, if placed in the scene, would be visible.
    */
-  public static function wouldNoteBeVisible(viewAreaBottom:Float, viewAreaTop:Float, eventData:SongEventData, ?origin:FlxObject):Bool
+  public static function wouldEventBeVisible(viewAreaBottom:Float, viewAreaTop:Float, eventData:SongEventData, ?origin:FlxObject):Bool
   {
     var noteHeight:Float = ChartEditorState.GRID_SIZE;
     var notePosY:Float = eventData.stepTime * ChartEditorState.GRID_SIZE;

source/funkin/ui/debug/charting/ChartEditorHoldNoteSprite.hx

@@ -52,6 +52,7 @@ class ChartEditorHoldNoteSprite extends SustainTrail
     strumTime = 999999999;
     missedNote = false;
     hitNote = false;
+    active = true;
     visible = true;
     alpha = 1.0;
     width = graphic.width / 8 * zoom; // amount of notes * 2
@@ -64,6 +65,19 @@ class ChartEditorHoldNoteSprite extends SustainTrail
     setup();
   }
 
+  public override function kill():Void
+  {
+    super.kill();
+
+    active = false;
+    visible = false;
+    noteData = null;
+    strumTime = 999999999;
+    noteDirection = 0;
+    sustainLength = 0;
+    fullSustainLength = 0;
+  }
+
   /**
    * Return whether this note is currently visible.
    */

source/funkin/ui/debug/charting/ChartEditorState.hx

@@ -2329,8 +2329,11 @@ class ChartEditorState extends HaxeUIState
         if (!ChartEditorHoldNoteSprite.wouldHoldNoteBeVisible(viewAreaBottomPixels, viewAreaTopPixels, noteData, renderedHoldNotes)) continue;
 
         // Hold note should be rendered.
-        var holdNoteSprite:ChartEditorHoldNoteSprite = renderedHoldNotes.recycle(() -> new ChartEditorHoldNoteSprite(this));
+        var holdNoteFactory = function() {
-        trace('Creating new HoldNote... (${renderedHoldNotes.members.length})');
+          // TODO: Print some kind of warning if `renderedHoldNotes.members` is too high?
+          return new ChartEditorHoldNoteSprite(this);
+        }
+        var holdNoteSprite:ChartEditorHoldNoteSprite = renderedHoldNotes.recycle(holdNoteFactory);
 
         var noteLengthPixels:Float = noteData.stepLength * GRID_SIZE;
 
@@ -2388,6 +2391,12 @@ class ChartEditorState extends HaxeUIState
       // Sort the events DESCENDING. This keeps the sustain behind the associated note.
       renderedEvents.sort(FlxSort.byY, FlxSort.DESCENDING);
     }
+
+    // Add a debug value which displays the current size of the note pool.
+    // The pool will grow as more notes need to be rendered at once.
+    // If this gets too big, something needs to be optimized somewhere! -Eric
+    FlxG.watch.addQuick("tapNotesRendered", renderedNotes.members.length);
+    FlxG.watch.addQuick("holdNotesRendered", renderedHoldNotes.members.length);
   }
 
   function buildSelectionSquare():FlxSprite
@@ -3095,6 +3104,17 @@ class ChartEditorState extends HaxeUIState
     #end
   }
 
+  /**
+   * Clear the voices group.
+   */
+  public function clearVocals():Void
+  {
+    audioVocalTrackGroup.clear();
+  }
+
+  /**
+   * Load a vocal track for a given song and character and add it to the voices group.
+   */
   public function loadVocalsFromAsset(path:String, charKey:String = null):Bool
   {
     var vocalTrack:FlxSound = FlxG.sound.load(path, 1.0, false);
@@ -3156,6 +3176,8 @@ class ChartEditorState extends HaxeUIState
 
     sortChartData();
 
+    clearVocals();
+
     loadInstrumentalFromAsset(Paths.inst(songId));
 
     var voiceList:Array<String> = song.getDifficulty(selectedDifficulty).buildVoiceList();