B37: Contact Hardening Soft Shadows using Erosion

Klein,A., Nischwitz,A., Obermeier,P.

In this paper, we present an image based method for computing contact hardening soft shadows by utilizing an erosion operator. Our method is based on shadow mapping and operates in screen space. By using object
silhouettes in hard shadows, we estimate the penumbra size and scale an erosion operator to generate the
penumbra areas. Furthermore, we present two solutions to generate the shadow factor for the penumbra areas.
Our method works best for small penumbras and can be easily integrated into existing shadow mapping based