ask about game background

Previously sorry with my english is not good.

any one please help me,
how i can make game like this :


I mean, not the windows mode. but the game does not have windows background.
please help me all

 

can i use unity to create a 3d game, but the back ground is the actual desktop?
for example as : Virtual dance girl, otaku maskot, sparticles, etc

 

A common way (at least at one time) to do this is to have your game simply take a screenshot of the desktop then use that image as the background in your game. So in reality it is not the desktop but looks like it is. These days with windows being able to be custom shapes you may be able to truly make the game right on the desktop. But using Unity the screenshot approach is probably your best bet.

 

I have never tried it, but check out this thread: http://forum.unity3d.com/threads/windows-api-calls.127719/

 

thank you very much to GarBenjamin and Mike 670 for respone, it all has helped me