Handle BGM Fade through Game_System and always force a BGM Play after…

… a fadeout otherwise this playing the same BGM again won't work.

Fix #1354

src/game_interpreter.cpp

@@ -1478,7 +1478,7 @@ bool Game_Interpreter::CommandPlayBGM(RPG::EventCommand const& com) { // code 11
 
 bool Game_Interpreter::CommandFadeOutBGM(RPG::EventCommand const& com) { // code 11520
 	int fadeout = com.parameters[0];
-	Audio().BGM_Fade(fadeout);
+	Game_System::BgmFade(fadeout);
 	return true;
 }
 

src/game_interpreter_map.cpp

@@ -492,7 +492,7 @@ bool Game_Interpreter_Map::ContinuationShowInnStart(RPG::EventCommand const& /*
 			actor->RemoveAllStates();
 		}
 		Graphics::Transition(Graphics::TransitionFadeOut, 36, true);
-		Audio().BGM_Fade(800);
+		Game_System::BgmFade(800);
 		SetContinuation(static_cast<ContinuationFunction>(&Game_Interpreter_Map::ContinuationShowInnContinue));
 		return false;
 	}

src/game_system.cpp

@@ -34,6 +34,8 @@
 namespace {
 	FileRequestBinding music_request_id;
 	std::map<std::string, FileRequestBinding> se_request_ids;
+	/** When true (BgmFade called) always forces a BGM_Play even when the same music is used */
+	bool force_bgm_play = false;
 
 	/**
 	 * Determines if the requested file is supposed to Stop BGM/SE play.
@@ -101,7 +103,7 @@ void Game_System::BgmPlay(RPG::Music const& bgm) {
 	// (OFF) means play nothing
 	if (!bgm.name.empty() && bgm.name != "(OFF)") {
 		// Same music: Only adjust volume and speed
-		if (previous_music.name == bgm.name) {
+		if (!force_bgm_play && previous_music.name == bgm.name) {
 			if (previous_music.volume != data.current_music.volume) {
 				if (!bgm_pending) { // Delay if not ready
 					Audio().BGM_Volume(data.current_music.volume);
@@ -122,6 +124,8 @@ void Game_System::BgmPlay(RPG::Music const& bgm) {
 	} else {
 		BgmStop();
 	}
+
+	force_bgm_play = false;
 }
 
 void Game_System::BgmStop() {
@@ -130,6 +134,11 @@ void Game_System::BgmStop() {
 	Audio().BGM_Stop();
 }
 
+void Game_System::BgmFade(int duration) {
+	Audio().BGM_Fade(duration);
+	force_bgm_play = true;
+}
+
 void Game_System::SePlay(RPG::Sound const& se) {
 	static bool ineluki_warning_shown = false;
 

src/game_system.h

@@ -106,6 +106,13 @@ namespace Game_System {
 	 */
 	void BgmStop();
 
+	/**
+	 * Fades out the current BGM
+	 *
+	 * @param duration Duration in ms
+	 */
+	void BgmFade(int duration);
+
 	/**
 	 * Plays a Sound.
 	 *

src/player.cpp

@@ -297,7 +297,7 @@ void Player::Update(bool update_scene) {
 		if (Scene::Find(Scene::Title) && Scene::instance->type != Scene::Title) {
 			Scene::PopUntil(Scene::Title);
 			// Fade out music and stop sound effects before returning
-			Audio().BGM_Fade(800);
+			Game_System::BgmFade(800);
 			Audio().SE_Stop();
 			// Do not update this scene until it's properly set up in the next main loop
 			update_scene = false;

src/scene_end.cpp

@@ -47,7 +47,7 @@ void Scene_End::Update() {
 		Game_System::SePlay(Game_System::GetSystemSE(Game_System::SFX_Decision));
 		switch (command_window->GetIndex()) {
 		case 0: // Yes
-			Audio().BGM_Fade(800);
+			Game_System::BgmFade(800);
 			Scene::PopUntil(Scene::Title);
 			break;
 		case 1: // No

src/scene_gamebrowser.cpp

@@ -50,7 +50,6 @@ void Scene_GameBrowser::Continue() {
 #ifdef _WIN32
 	SetCurrentDirectory(L"..");
 #endif
-	Audio().BGM_Fade(800);
 
 	Main_Data::SetProjectPath(browser_dir);