From ca345e6c4fad9cc7fd3e6d0de41e68a6cb0298b9 Mon Sep 17 00:00:00 2001
From: EliteMasterEric <ericmyllyoja@gmail.com>
Date: Thu, 6 Jun 2024 21:38:00 -0400
Subject: [PATCH] Play song IDs based on the chart file's "instrumental" field,
 not the variation ID.

---
 source/funkin/play/PlayState.hx            |  9 ++++++++-
 source/funkin/play/song/Song.hx            |  4 ++--
 source/funkin/ui/freeplay/FreeplayState.hx | 18 ++++++++++++++----
 3 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/source/funkin/play/PlayState.hx b/source/funkin/play/PlayState.hx
index b02cc69f7..6bc4b2d89 100644
--- a/source/funkin/play/PlayState.hx
+++ b/source/funkin/play/PlayState.hx
@@ -175,6 +175,12 @@ class PlayState extends MusicBeatSubState
    */
   public var currentVariation:String = Constants.DEFAULT_VARIATION;
 
+  /**
+   * The currently selected instrumental ID.
+   * @default `''`
+   */
+  public var currentInstrumental:String = '';
+
   /**
    * The currently active Stage. This is the object containing all the props.
    */
@@ -603,6 +609,7 @@ class PlayState extends MusicBeatSubState
     currentSong = params.targetSong;
     if (params.targetDifficulty != null) currentDifficulty = params.targetDifficulty;
     if (params.targetVariation != null) currentVariation = params.targetVariation;
+    if (params.targetInstrumental != null) currentInstrumental = params.targetInstrumental;
     isPracticeMode = params.practiceMode ?? false;
     isBotPlayMode = params.botPlayMode ?? false;
     isMinimalMode = params.minimalMode ?? false;
@@ -1968,7 +1975,7 @@ class PlayState extends MusicBeatSubState
 
     if (!overrideMusic && !isGamePaused && currentChart != null)
     {
-      currentChart.playInst(1.0, false);
+      currentChart.playInst(1.0, currentInstrumental, false);
     }
 
     if (FlxG.sound.music == null)
diff --git a/source/funkin/play/song/Song.hx b/source/funkin/play/song/Song.hx
index df3e343e2..dde5ee7b8 100644
--- a/source/funkin/play/song/Song.hx
+++ b/source/funkin/play/song/Song.hx
@@ -682,9 +682,9 @@ class SongDifficulty
     FlxG.sound.cache(getInstPath(instrumental));
   }
 
-  public function playInst(volume:Float = 1.0, looped:Bool = false):Void
+  public function playInst(volume:Float = 1.0, instId:String = '', looped:Bool = false):Void
   {
-    var suffix:String = (variation != null && variation != '' && variation != 'default') ? '-$variation' : '';
+    var suffix:String = (instId != '') ? '-$instId' : '';
 
     FlxG.sound.music = FunkinSound.load(Paths.inst(this.song.id, suffix), volume, looped, false, true);
 
diff --git a/source/funkin/ui/freeplay/FreeplayState.hx b/source/funkin/ui/freeplay/FreeplayState.hx
index 607b7a353..c47933fd7 100644
--- a/source/funkin/ui/freeplay/FreeplayState.hx
+++ b/source/funkin/ui/freeplay/FreeplayState.hx
@@ -1726,11 +1726,20 @@ class FreeplayState extends MusicBeatSubState
       FlxG.log.warn('WARN: could not find song with id (${cap.songData.songId})');
       return;
     }
-    var targetDifficulty:String = currentDifficulty;
-    var targetVariation:String = targetSong.getFirstValidVariation(targetDifficulty);
-
+    var targetDifficultyId:String = currentDifficulty;
+    var targetVariation:String = targetSong.getFirstValidVariation(targetDifficultyId);
     PlayStatePlaylist.campaignId = cap.songData.levelId;
 
+    var targetDifficulty:SongDifficulty = targetSong.getDifficulty(targetDifficultyId, targetVariation);
+    if (targetDifficulty == null)
+    {
+      FlxG.log.warn('WARN: could not find difficulty with id (${targetDifficultyId})');
+      return;
+    }
+
+    // TODO: Change this with alternate instrumentals
+    var targetInstId:String = targetDifficulty.characters.instrumental;
+
     // Visual and audio effects.
     FunkinSound.playOnce(Paths.sound('confirmMenu'));
     dj.confirm();
@@ -1779,8 +1788,9 @@ class FreeplayState extends MusicBeatSubState
       LoadingState.loadPlayState(
         {
           targetSong: targetSong,
-          targetDifficulty: targetDifficulty,
+          targetDifficulty: targetDifficultyId,
           targetVariation: targetVariation,
+          targetInstrumental: targetInstId,
           practiceMode: false,
           minimalMode: false,