I've implemented the "screen space soft shadows" technique (in OGL):
[Gumbau] Jesus Gumbau, Miguel Chover, and Mateu Sbert, “Screen-Space Soft Shadows”, GPU Pro, pp. 477 – 490
The shadow looks nice and soft, however making the shadow soft didn't remove the blockiness. I found out that this can be reduced by increasing the shadow map size from 1024 to 2048 ( and so on ), but this kills performance, and memory bandwith. Is there some kind of filtering technique that can reduce this basic blocky property of shadow mapping? So that soft shadows can really look soft. Not blocky soft
I've attached a picture with soft shadows turned up, and of the simple shadow map.