Merge pull request #6587 from jherico/rigel

Fix crashes on exit due to poor cleanup

interface/src/Application.cpp

@@ -1077,6 +1077,11 @@ void Application::initializeUi() {
 }
 
 void Application::paintGL() {
+    // paintGL uses a queued connection, so we can get messages from the queue even after we've quit 
+    // and the plugins have shutdown
+    if (_aboutToQuit) {
+        return;
+    }
     _frameCount++;
 
     // update fps moving average

libraries/display-plugins/src/display-plugins/OpenGLDisplayPlugin.cpp

@@ -30,6 +30,12 @@ class PresentThread : public QThread, public Dependency {
     using Lock = std::unique_lock<Mutex>;
 public:
 
+    PresentThread() {
+        connect(qApp, &QCoreApplication::aboutToQuit, [this]{
+            _shutdown = true;
+        });
+    }
+
     ~PresentThread() {
         _shutdown = true;
         wait(); 
@@ -99,6 +105,10 @@ public:
             _context->doneCurrent();
         }
 
+        _context->makeCurrent();
+        if (_activePlugin) {
+            _activePlugin->uncustomizeContext();
+        }
         _context->doneCurrent();
         _context->moveToThread(qApp->thread());
     }

libraries/gl/src/gl/OffscreenQmlSurface.cpp

@@ -337,6 +337,9 @@ void OffscreenQmlSurface::create(QOpenGLContext* shareContext) {
     // a timer with a small interval is used to get better performance.
     _updateTimer.setInterval(MIN_TIMER_MS);
     connect(&_updateTimer, &QTimer::timeout, this, &OffscreenQmlSurface::updateQuick);
+    QObject::connect(qApp, &QCoreApplication::aboutToQuit, [this]{
+        disconnect(&_updateTimer, &QTimer::timeout, this, &OffscreenQmlSurface::updateQuick);
+    });
     _updateTimer.start();
 
     _qmlComponent = new QQmlComponent(_qmlEngine);