qmlgloverlay: reset gl state after drawing

commit 00777d80

qt/gloverlay: reset OpenGL state after Qt drawing

Reset to the original OpenGL state as required by the OpenGL API
contract.  Fixes output with a glimagesink element downstream.

commit d59fa1e8

qt/gloverlay: reset current OpenGL context after Qt

Qt may replace the drawable with its own which breaks output if Qt is
not displaying the resulting video as used with e.g. glimagesink.

ext/qt/qtglrenderer.cc

@@ -636,6 +636,12 @@ void GstQuickRenderer::initializeGstGL ()
         m_sharedRenderData->m_animationDriver->install();
     }
     g_mutex_unlock (&m_sharedRenderData->lock);
+    /* XXX: reset the OpenGL context drawable as Qt may have clobbered it.
+     * Fixes glimagesink output where Qt replaces the Surface to use in its
+     * own MakeCurrent call.  Qt does this on it's OpenGL initialisation
+     * the the rendering engine. */
+    gst_gl_context_activate (gl_context, FALSE);
+    gst_gl_context_activate (gl_context, TRUE);
 }
 
 void GstQuickRenderer::initializeQml()