Fix crash when trying to use ref audio for two songs

Author: OctoFlareDev

objects/obj_song/Create_0.gml

@@ -9,6 +9,8 @@ song_backupid = string(floor(random(800000)))
 song_backupname = "Unsaved song " + string(song_backupid) + ".nbs"
 song_download_display_name = ""
 
+reference_audio_buffer = -1
+
 // Playback
 tempo = 10
 real_tempo = 10

scripts/load_reference_audio/load_reference_audio.gml

@@ -1,8 +1,9 @@
 function load_reference_audio(){
 	audio_destroy_stream(songs[song].reference_audio)
 	audio_free_buffer_sound(songs[song].reference_audio)
-	buffer_delete(global.__temp_audio_buffer__)
+	buffer_delete(songs[song].reference_audio_buffer)
 	global.__temp_audio_buffer__ = -1
+	songs[song].reference_audio_buffer = -1
 	songs[song].reference_audio_file = ""
 	songs[song].reference_audio = -1
 	songs[song].reference_option = 2
@@ -16,6 +17,7 @@ function load_reference_audio(){
 	} else if (string_lower(filename_ext(songs[song].reference_audio_file)) == ".wav") {
 		songs[song].reference_audio = wav_load_buffer(songs[song].reference_audio_file)
 	}
+	songs[song].reference_audio_buffer = global.__temp_audio_buffer__
 	if (songs[song].reference_audio < 0) {
 		if (language != 1) message("Couldn't load the file", "Error")
 		else message("文件加载失败", "错误")