parallel-split shadow maps for large-scale virtual environments
Shadowing effects dramatically enhance the realism of virtual environments by providing useful visual cues. Shadow mapping is an efficient algorithm for real-time shadow rendering, which is extensively adopted in real-time applications by its generality and efficiency. However, shadow mapping usually suffers from the inherent aliasing errors due to the image-based nature. In this paper, we present the Parallel-Split Shadow Maps (PSSMs) scheme, which splits the view frustum into different parts by using the planes parallel to the view plane and then generates multiple smaller shadow maps for the split parts. A fast and robust split strategy based on the analysis of shadow map aliasing has been proposed, which produces a moderate aliasing distribution over the whole depth range. By applying the geometry approximation procedure to each of the split parts instead of the whole scene, the tighter bounding shapes of visible objects enhance the utilization of the shadow map resolution. Hardware-acceleration is used to remove the extra rendering passes when synthesizing the scene-shadows. Our approach is intuitive to implement without using complex data structures, with real-time performance for dynamic and large-scale virtual environments.
parallel shadow shadow mapping maps maps large-scale large-scale virtual environments virtual environment effect visualization efficiency algorithm real-time rendering applications general aliasing errors paper scheme robust strategies analysis distributed geometry approximation shape object complexity data structures performance dynamic hardware acceleration image-based rendering map image