Handle context loss in the basic render loop

In the event of a graphics context loss, we need to reset the scenegraph
and the GL context.

As all windows share a graphics context a loss detected in one window
needs to reset the scenegraph on all windows.

Change-Id: I3ff1a93d5a08fa21366a6a56e94bd2185aebb2d5
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

1 files changed, 18 insertions, 0 deletions

diff --git a/src/quick/scenegraph/qsgrenderloop.cpp b/src/quick/scenegraph/qsgrenderloop.cpp
index ba231f8159..f609055677 100644
--- a/src/quick/scenegraph/qsgrenderloop.cpp
+++ b/src/quick/scenegraph/qsgrenderloop.cpp
@@ -619,6 +619,24 @@ void QSGGuiThreadRenderLoop::renderWindow(QQuickWindow *window)
         i++;
     }
 
+    // Check for context loss.
+    if (!current && !rhi && !gl->isValid()) {
+        for (auto it = m_windows.constBegin() ; it != m_windows.constEnd(); it++) {
+            QQuickWindowPrivate *windowPrivate = QQuickWindowPrivate::get(it.key());
+            windowPrivate->cleanupNodesOnShutdown();
+        }
+        rc->invalidate();
+        current = gl->create() && gl->makeCurrent(window);
+        if (current) {
+            QSGDefaultRenderContext::InitParams rcParams;
+            rcParams.sampleCount = qMax(1, gl->format().samples());
+            rcParams.openGLContext = gl;
+            rcParams.initialSurfacePixelSize = window->size() * window->effectiveDevicePixelRatio();
+            rcParams.maybeSurface = window;
+            rc->initialize(&rcParams);
+        }
+    }
+
     if (!current)
         return;