/*!   \page opengl-overlay-example.html

  \ingroup opengl-examples
  \title OpenGL Overlay Example

This example demonstrates how to use OpenGL overlays with the Qt OpenGL
Extension. It features a QGLWidget with a relatively expensive redrawing
operation, and rubber-band drawing in the overlay plane. Using the
overlay has the advantage that the rubber-band may be drawn and erased
without damaging the image in the main plane, so costly redraws are
avoided.

See \c{$QTDIR/examples/opengl/overlay} for the source code.

*/