Fix BadDrawable errors when re-parenting a QGLWidget on X11/EGL

It's actually not really reparenting, but calling setWindowFlags which
triggered the errors. But setWindowFlags causes a re-parent.

The context isn't really the right please to free the surface, but
fixing that is a much more intrusive change.

Reviewed-By: TrustMe

1 files changed, 13 insertions, 2 deletions

diff --git a/src/opengl/qgl_egl.cpp b/src/opengl/qgl_egl.cpp
index 6c93beaf3e..fa876c7972 100644
--- a/src/opengl/qgl_egl.cpp
+++ b/src/opengl/qgl_egl.cpp
@@ -142,8 +142,19 @@ void QGLContext::reset()
     d->cleanup();
     doneCurrent();
     if (d->eglContext) {
-        if (d->eglSurface != EGL_NO_SURFACE)
-            eglDestroySurface(d->eglContext->display(), d->eglSurface);
+        if (d->eglSurface != EGL_NO_SURFACE) {
+#ifdef Q_WS_X11
+            // Make sure we don't call eglDestroySurface on a surface which
+            // was created for a different winId:
+            if (d->paintDevice->devType() == QInternal::Widget) {
+                QGLWidget* w = static_cast<QGLWidget*>(d->paintDevice);
+
+                if (w->d_func()->eglSurfaceWindowId == w->winId())
+                    eglDestroySurface(d->eglContext->display(), d->eglSurface);
+            } else
+#endif
+                eglDestroySurface(d->eglContext->display(), d->eglSurface);
+        }
         delete d->eglContext;
     }
     d->eglContext = 0;