minor example added

Signed-off-by: Marcin Kolny <marcin.kolny@flytronic.pl>
A first try.

Signed-off-by: Marcin Kolny <marcin.kolny@flytronic.pl>
A second try.

Signed-off-by: Marcin Kolny <marcin.kolny@flytronic.pl>
OpenGL works.

Signed-off-by: Marcin Kolny <marcin.kolny@flytronic.pl>