Heroes of Might and Magic V for those with older computers and weak graphics cards.

A shader is a special program that uses specific programmable registers of the video card to create various graphical effects (such as shadows)...

As for the patch, there are some problems... I don't need it anymore. I simply upgraded my hardware a long time ago :D ... and I don't remember where I downloaded it, but I think you can find it yourself if you want. ;)