High-Quality Shadows for Streaming Terrain Rendering
Matthäus G. Chajdas, Florian Reichl, Christian Dick, Rüdiger Westermann
Technische Universität München
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.