Real-Time Shadow Volume Algorithm for Subdivision Surface Based Models

This paper presents a purely hardware-accelerated shadow volume algorithm for subdivision surface based models. By introducing SP (subdivision patterns), all procedures, including subdivision evaluation, silhouette extraction, shadow volume generation, and shadow rendering are executed on GPU (Graphics Process Units) efficiently. This not only alleviates the burden of CPU, but also guarantees the consistency of data among different processing stages. This also makes it possible to integrate some special effects imposed by other shaders, e.g., displacement mapping or vertex texturing, with the shadow volume algorithm. Experiments show that the algorithm is efficient, robust, and can be easily extended to other subdivision schemes and parametric surfaces.