SE Screen-Space Shadows provides screen-space raytraced shadows for directional lights for sharp, detailed contact shadows. It can capture details in shadows that would otherwise be missed using traditional shadow maps alone.
This effect works by tracing in screen-space using the depth buffer information, similar to SSAO or screen-space reflections. Like these other effects, anything that is not directly visible in the main view will not contribute to screen-space shadows. However, because this effect is meant to be used in combination with traditional shadow maps to improve close-proximity contact shadows, this limitation is generally not apparent.
