Adaptive Global Visibility Sampling

Jiří Bittner Oliver Mattausch Peter Wonka Vlastimil Havran Michael Wimmer
ACM Transactions on Graphics (Proceedings of SIGGRAPH 2009) 28(3):94, 2009
In this paper we propose a global visibility algorithm which computes from-region visibility for all view cells simultaneously in a progressive manner. We cast rays to sample visibility interactions and use the information carried by a ray for all view cells it intersects. The main contribution of the paper is a set of adaptive sampling strategies based on ray mutations that exploit the spatial coherence of visibility. Our method achieves more than an order of magnitude speedup compared to per-view cell sampling. This provides a practical solution to visibility preprocessing and also enables a new type of interactive visibility analysis application, where it is possible to quickly inspect and modify a coarse global visibility solution that is constantly refined.