From 42e9a5e27c914c58dc9c734829f906fb7bb4f371 Mon Sep 17 00:00:00 2001
From: Laszlo Agocs <laszlo.agocs@qt.io>
Date: Tue, 4 Apr 2017 11:36:19 +0200
Subject: Make QQuickWidget cleanup work with engines that alter the context

To make Scene3D in a QQuickWidget work.

Task-number: QTBUG-52132
Change-Id: I686ff36d82a1c7bdfdcd7080a314bb9afdb7be88
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>
Reviewed-by: Andy Nichols <andy.nichols@qt.io>
---
 src/quickwidgets/qquickwidget.cpp | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/quickwidgets/qquickwidget.cpp b/src/quickwidgets/qquickwidget.cpp
index 5d7fb04b9f..be5837723a 100644
--- a/src/quickwidgets/qquickwidget.cpp
+++ b/src/quickwidgets/qquickwidget.cpp
@@ -157,6 +157,16 @@ void QQuickWidgetPrivate::invalidateRenderControl()
 #endif
 
     renderControl->invalidate();
+
+    // Many things can happen inside the above invalidate() call, including a
+    // change of current context. Restore if needed since some code will rely
+    // on the fact that this function makes and leaves the context current.
+#if QT_CONFIG(opengl)
+    if (!useSoftwareRenderer && context) {
+        if (QOpenGLContext::currentContext() != context)
+            context->makeCurrent(offscreenSurface);
+    }
+#endif
 }
 
 void QQuickWidgetPrivate::handleWindowChange()
-- 
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