Some time ago I wondered if this could be done with a small CCD (Like the one in your mouse, see the mouse-scanner project: http://spritesmods.com/?art=mouseeye

Some time ago I wondered if this could be done with a small CCD (Like the one in your mouse, see the mouse-scanner project: http://spritesmods.com/?art=mouseeye http://spritesmods.com/?art=mouseeye). I tried it once, but it's very hard to do this in real-time.