Rework Conductor to use instanced signals

source/funkin/Conductor.hx

@@ -36,23 +36,43 @@ class Conductor
    * You can also do stuff like store a reference to the Conductor and pass it around or temporarily replace it,
    * or have a second Conductor running at the same time, or other weird stuff like that if you need to.
    */
-  public static var instance:Conductor = new Conductor();
+  public static var instance(get, set):Conductor;
+
+  static var _instance:Null<Conductor> = null;
 
   /**
-   * Signal fired when the current Conductor instance advances to a new measure.
+   * Signal fired when the current static Conductor instance advances to a new measure.
    */
   public static var measureHit(default, null):FlxSignal = new FlxSignal();
 
+  /**
+   * Signal fired when THIS Conductor instance advances to a new measure.
+   * TODO: This naming sucks but we can't make a static and instance field with the same name!
+   */
+  public var onMeasureHit(default, null):FlxSignal = new FlxSignal();
+
   /**
    * Signal fired when the current Conductor instance advances to a new beat.
    */
   public static var beatHit(default, null):FlxSignal = new FlxSignal();
 
+  /**
+   * Signal fired when THIS Conductor instance advances to a new beat.
+   * TODO: This naming sucks but we can't make a static and instance field with the same name!
+   */
+  public var onBeatHit(default, null):FlxSignal = new FlxSignal();
+
   /**
    * Signal fired when the current Conductor instance advances to a new step.
    */
   public static var stepHit(default, null):FlxSignal = new FlxSignal();
 
+  /**
+   * Signal fired when THIS Conductor instance advances to a new step.
+   * TODO: This naming sucks but we can't make a static and instance field with the same name!
+   */
+  public var onStepHit(default, null):FlxSignal = new FlxSignal();
+
   /**
    * The list of time changes in the song.
    * There should be at least one time change (at the beginning of the song) to define the BPM.
@@ -234,6 +254,81 @@ class Conductor
     return Std.int(timeSignatureNumerator / timeSignatureDenominator * Constants.STEPS_PER_BEAT * Constants.STEPS_PER_BEAT);
   }
 
+  /**
+   * Reset the Conductor, replacing the current instance with a fresh one.
+   */
+  public static function reset():Void
+  {
+    set_instance(new Conductor());
+  }
+
+  /**
+   * Add values of the current main Conductor instance to the `FlxG.watch`.
+   */
+  public static function watchQuick():Void
+  {
+    FlxG.watch.addQuick("songPosition", Conductor.instance.songPosition);
+    FlxG.watch.addQuick("bpm", Conductor.instance.bpm);
+    FlxG.watch.addQuick("currentMeasureTime", Conductor.instance.currentMeasureTime);
+    FlxG.watch.addQuick("currentBeatTime", Conductor.instance.currentBeatTime);
+    FlxG.watch.addQuick("currentStepTime", Conductor.instance.currentStepTime);
+  }
+
+  static function dispatchMeasureHit():Void
+  {
+    Conductor.measureHit.dispatch();
+  }
+
+  static function dispatchBeatHit():Void
+  {
+    Conductor.beatHit.dispatch();
+  }
+
+  static function dispatchStepHit():Void
+  {
+    Conductor.stepHit.dispatch();
+  }
+
+  static function setupSingleton(input:Conductor):Void
+  {
+    input.onMeasureHit.add(dispatchMeasureHit);
+
+    input.onBeatHit.add(dispatchBeatHit);
+
+    input.onStepHit.add(dispatchStepHit);
+  }
+
+  static function clearSingleton(input:Conductor):Void
+  {
+    input.onMeasureHit.remove(dispatchMeasureHit);
+
+    input.onBeatHit.remove(dispatchBeatHit);
+
+    input.onStepHit.remove(dispatchStepHit);
+  }
+
+  static function get_instance():Conductor
+  {
+    if (Conductor._instance == null) set_instance(new Conductor());
+    if (Conductor._instance == null) throw "Could not initialize singleton Conductor!";
+    return Conductor._instance;
+  }
+
+  static function set_instance(instance:Conductor):Conductor
+  {
+    // Use _instance in here to avoid recursion
+    if (Conductor._instance != null) clearSingleton(Conductor._instance);
+
+    Conductor._instance = instance;
+
+    if (Conductor._instance != null) setupSingleton(Conductor._instance);
+
+    return Conductor._instance;
+  }
+
+  /**
+   * The constructor.
+   */
   public function new() {}
 
   /**
@@ -244,6 +339,7 @@ class Conductor
    *
    * WARNING: Avoid this for things like setting the BPM of the title screen music,
    * you should have a metadata file for it instead.
+   * We should probably deprecate this in the future.
    */
   public function forceBPM(?bpm:Float = null)
   {
@@ -264,7 +360,7 @@ class Conductor
    * BPM, current step, etc. will be re-calculated based on the song position.
    *
    * @param	songPosition The current position in the song in milliseconds.
-   *        Leave blank to use the FlxG.sound.music position.
+   *        Leave blank to use the `FlxG.sound.music` position.
    */
   public function update(?songPos:Float)
   {
@@ -317,27 +413,27 @@ class Conductor
       this.currentMeasure = Math.floor(currentMeasureTime);
     }
 
-    // Only fire the signal if we are THE Conductor.
-    if (this == Conductor.instance)
+    // FlxSignals are really cool.
+    if (currentStep != oldStep)
     {
-      // FlxSignals are really cool.
-      if (currentStep != oldStep)
-      {
-        Conductor.stepHit.dispatch();
-      }
+      this.onStepHit.dispatch();
+    }
 
-      if (currentBeat != oldBeat)
-      {
-        Conductor.beatHit.dispatch();
-      }
+    if (currentBeat != oldBeat)
+    {
+      this.onBeatHit.dispatch();
+    }
 
-      if (currentMeasure != oldMeasure)
-      {
-        Conductor.measureHit.dispatch();
-      }
+    if (currentMeasure != oldMeasure)
+    {
+      this.onMeasureHit.dispatch();
     }
   }
 
+  /**
+   * Apply the time changes from a SongMetadata file.
+   * @param songTimeChanges The time changes to apply.
+   */
   public function mapTimeChanges(songTimeChanges:Array<SongTimeChange>)
   {
     timeChanges = [];
@@ -383,7 +479,8 @@ class Conductor
   }
 
   /**
-   * Given a time in milliseconds, return a time in steps.
+   * @param ms A timestamp in milliseconds.
+   * @return The corresponding time in steps.
    */
   public function getTimeInSteps(ms:Float):Float
   {
@@ -420,7 +517,8 @@ class Conductor
   }
 
   /**
-   * Given a time in steps and fractional steps, return a time in milliseconds.
+   * @param stepTime A timestamp in steps.
+   * @return The corresponding time in milliseconds.
    */
   public function getStepTimeInMs(stepTime:Float):Float
   {
@@ -456,7 +554,8 @@ class Conductor
   }
 
   /**
-   * Given a time in beats and fractional beats, return a time in milliseconds.
+   * @param beatTime A timestamp in fractional beats.
+   * @return The corresponding time in milliseconds.
    */
   public function getBeatTimeInMs(beatTime:Float):Float
   {
@@ -490,21 +589,4 @@ class Conductor
       return resultMs;
     }
   }
-
-  public static function watchQuick():Void
-  {
-    FlxG.watch.addQuick("songPosition", Conductor.instance.songPosition);
-    FlxG.watch.addQuick("bpm", Conductor.instance.bpm);
-    FlxG.watch.addQuick("currentMeasureTime", Conductor.instance.currentMeasureTime);
-    FlxG.watch.addQuick("currentBeatTime", Conductor.instance.currentBeatTime);
-    FlxG.watch.addQuick("currentStepTime", Conductor.instance.currentStepTime);
-  }
-
-  /**
-   * Reset the Conductor, replacing the current instance with a fresh one.
-   */
-  public static function reset():Void
-  {
-    Conductor.instance = new Conductor();
-  }
 }

source/funkin/play/song/Song.hx

@@ -374,12 +374,16 @@ class Song implements IPlayStateScriptedClass implements IRegistryEntry<SongMeta
 
   public function getFirstValidVariation(?diffId:String, ?possibleVariations:Array<String>):Null<String>
   {
-    if (variations == null) possibleVariations = variations;
+    if (possibleVariations == null)
+    {
+      possibleVariations = variations;
+      possibleVariations.sort(SortUtil.defaultsThenAlphabetically.bind(Constants.DEFAULT_VARIATION_LIST));
+    }
     if (diffId == null) diffId = listDifficulties(null, possibleVariations)[0];
 
-    for (variation in variations)
+    for (variationId in possibleVariations)
     {
-      if (difficulties.exists('$diffId-$variation')) return variation;
+      if (difficulties.exists('$diffId-$variationId')) return variationId;
     }
 
     return null;

source/funkin/util/Constants.hx

@@ -157,6 +157,11 @@ class Constants
    */
   public static final DEFAULT_VARIATION:String = 'default';
 
+  /**
+   * Standardized variations for charts
+   */
+  public static final DEFAULT_VARIATION_LIST:Array<String> = ['default', 'erect', 'pico'];
+
   /**
    * The default intensity for camera zooms.
    */