thanks, I put it in my code.
in this project I use only depth and a light bleeding calculation, no depth^2, based on GPU Gems 3 (now free to read), but will try out other methods too.

basically I need a fast shadowmapping solution over large distances and for lot of entities, so I have to try everything the shade-c based one is better now (I had a lot of work with its corrections), but I think this solution also can be okay soon... I know I have to learn a lot of about shadowmapping...