skybox subsetter

Assets/Scripts/EditorGame/Base/ProjectFiles/SongInformation.cs

@@ -13,6 +13,7 @@ namespace Ichni.RhythmGame
         public float bpm; //每分钟节拍数
         public float delay; //设定音乐和谱面延迟Delay秒后开始，在延迟中，SongPosition为负数。
 
+        public float songLength;
         public float songTime;
         public float songBeat => songTime / 60 * bpm;
 
@@ -25,7 +26,18 @@ namespace Ichni.RhythmGame
             this.delay = delay;
             songLocation = EditorManager.instance.projectInformation.projectPath + "/" + songName;
             Debug.Log("Loading song from " + songLocation + " " + ES3.FileExists(songLocation));
-            song = ES3.LoadAudio(songLocation, AudioType.WAV);
+            
+            string extension = System.IO.Path.GetExtension(songLocation).ToLower();
+
+            song = extension switch
+            {
+                ".mp3" => ES3.LoadAudio(songLocation, AudioType.MPEG),
+                ".ogg" => ES3.LoadAudio(songLocation, AudioType.OGGVORBIS),
+                ".wav" => ES3.LoadAudio(songLocation, AudioType.WAV),
+                _ => throw new System.Exception("Unsupported audio format: " + extension)
+            };
+            
+            songLength = song.length;
         }
 
         public void SaveBM()