Nothing too fancy :] Three colors that you see on screen mean that given geometry will be using different shadow maps. Pretty basic techniques in current games.
If you think that this look weird then you are right. This is just visualization of first part of work, there is still a lot of issues and artifacts. The rest well wait till I finish small changes in render system. I plan them for some time and thanks to this work I had finally occasion to do them :]
So see you soon with another bunch of development news.