A Real-Time Anti-Aliasing Shadow Algorithm Based on Shadow Maps

Shadow mapping is an efficient algorithm for real-time shadow rendering. This algorithm is image based. When a shadow map with limited resolution maps in to a large virtual scene, it will suffer from the aliasing errors due to it\´s insufficient sample. In this paper we present a real-time shadow mapping algorithm. We render some sub shadow maps respectively instead of render only one shadow map and then map them into virtual scene respectively. This algorithm can handle aliasing errors by virtually increasing the resolution of the shadow map beyond the GPU hardware limit. Further more, a method called "deferred shadowing" is used to speed up the shadowing algorithm we have presented to meet the real-time rendering requirement in large virtual environment.