Fix more race conditions in AOLayer loading

- Uninitialized exit_loop variable
- Previous load task should stop completely before starting new load task

include/aolayer.h

@@ -148,7 +148,7 @@ private:
 
   // used in populate_vectors
   void load_next_frame();
-  std::atomic_bool exit_loop; //awful solution but i'm not fucking using QThread
+  std::atomic_bool exit_loop = false; //awful solution but i'm not fucking using QThread
   QFuture<void> frame_loader;
   QMutex mutex;
   QWaitCondition frameAdded;

src/aolayer.cpp

@@ -284,9 +284,11 @@ void AOLayer::start_playback(QString p_image)
     this->kill();
     return;
   }
-  QMutexLocker locker(&mutex);
+
   if (frame_loader.isRunning())
     exit_loop = true; // tell the loader to stop, we have a new image to load
+
+  QMutexLocker locker(&mutex);
   this->show();
 
   if (!ao_app->is_continuous_enabled()) {
@@ -561,12 +563,19 @@ void AOLayer::movie_ticker()
 }
 
 void AOLayer::populate_vectors() {
+#ifdef DEBUG_MOVIE
+  qDebug() << "[AOLayer::populate_vectors] Started thread";
+#endif
   while (!exit_loop && movie_frames.size() < max_frames) {
     load_next_frame();
 #ifdef DEBUG_MOVIE
     qDebug() << "[AOLayer::populate_vectors] Loaded frame" << movie_frames.size();
 #endif
   }
+#ifdef DEBUG_MOVIE
+  if (exit_loop)
+    qDebug() << "[AOLayer::populate_vectors] Exit requested";
+#endif
   exit_loop = false;
 }