GRIM/EMI: Draw movie subtitles while holding frame lock

This prevents a crash that occurs if the movie player deletes the
active subtitle while the main loop is still in the process of drawing
it.

engines/grim/grim.cpp

@@ -619,9 +619,9 @@ void GrimEngine::updateDisplayScene() {
 		}
 		// Draw Primitives
 		_iris->draw();
-		if (_movieSubtitle) {
-			_movieSubtitle->draw();
-		}
+
+		g_movie->drawMovieSubtitle();
+
 	} else if (_mode == NormalMode || _mode == OverworldMode) {
 		updateNormalMode();
 	} else if (_mode == DrawMode) {
@@ -1356,6 +1356,11 @@ void GrimEngine::setMovieSubtitle(TextObject *to) {
 	}
 }
 
+void GrimEngine::drawMovieSubtitle() {
+	if (_movieSubtitle)
+		_movieSubtitle->draw();
+}
+
 void GrimEngine::setMovieSetup() {
 	_movieSetup = _currSet->getCurrSetup()->_name;
 }

engines/grim/grim.h

@@ -161,6 +161,7 @@ public:
 	bool areActorsTalking() const;
 	void immediatelyRemoveActor(Actor *actor);
 
+	void drawMovieSubtitle();
 	void setMovieSubtitle(TextObject *to);
 	void setMovieSetup();
 

engines/grim/movie/movie.cpp

@@ -123,6 +123,11 @@ Graphics::Surface *MoviePlayer::getDstSurface() {
 	return _externalSurface;
 }
 
+void MoviePlayer::drawMovieSubtitle() {
+	Common::StackLock lock(_frameMutex);
+	g_grim->drawMovieSubtitle();
+}
+
 void MoviePlayer::init() {
 	if (!_timerStarted) {
 		g_system->getTimerManager()->installTimerProc(&timerCallback, 10000, this, "movieLoop");

engines/grim/movie/movie.h

@@ -79,6 +79,9 @@ public:
 	virtual void clearUpdateNeeded() { _updateNeeded = false; }
 	virtual int32 getMovieTime() { return (int32)_movieTime; }
 
+	/* Draw the subtitles, guarded by _drawMutex */
+	void drawMovieSubtitle();
+
 	/**
 	 * Saves the state of the video to a savegame
 	 * @param state         The state to save to