Fullscreen mask transition

Does anyone know the best way to make a fullscreen mask transition effect in AS3 ? Im just curious as to how this is done. I can make regular transitions…but create them in fullscreen not so sure about. Example of a particular one is Here If you hover over the “works” menu link then choose a project, you can see the transition effect!

like a screenshot.and break into pieces.then you can do transition whatever you like.not so hard