High-Quality Shadows for Streaming Terrain Rendering
Rendering of large, detailed 3D terrains on commodity hardware has become possible through the use of ray-casting, data caching and prefetching. Adding dynamic shadows as they appear during a day-night cycle remais a challenge however, because shadow rendering requires access to the entire terrain, invalidating data streaming strategies.
In this work we present a novel, practicable shadow rendering approach which distinguishes between near- and precomputed far-shadows to significantly reduce data access and runtime costs. While near-shadows are ray-traced using the current cache content, far-shadows are precomputed and stored in a very compact format requiring approximately 3 bit per height-map sample for an entire day-night cycle.
The authors wish to thank the Landesvermessungsamt Feldkirch, Austria and the State of Utah for providing high resolution geo data.
Accompanying video of the paper [55 MB AVI]