Separating-Plane Perspective Shadow Mapping

This paper proposes a real-time hybrid solution between standard shadow mapping and any of the current perspective shadow mapping based methods. Existing methods are known to have undersampling problems. At little extra cost we combine two methods to minimize undersampling errors. This is done by computing a plane equation which separates the two resulting shadow maps to get the best possible area-based sampling density. An additional property of this separation plane is that objects entirely on one side of the plane only need to be rendered into one map.