I am building my own graphic engine.My depth texture is significantly smaller than that of the screen.The low resolution depth map results in rigid shadow like this...I am sure this is a common issue.I would like to learn go to technique to resolve this issue.
In forward rendering what's the go to technique to smooth out rigid shadow due to low resolution shadowmap texture?
shadow;shadow mapping
Percentage Closer Filtering with some amount of blur (ie. a minimum filter size in texture space) is the most basic method I know of. For example, see GPU Gems. My experience is that it is also quite robust.