Supporting scalable peer to peer virtual environments using frontier sets

We present a scalable implementation of a network partitioning scheme that we have called frontier sets. Frontier sets build on the notion of a potentially visible set (PVS) [1][22]. In a PVS, a world is sub-divided into cells and for each cell all the other cells that can be seen are computed. In contrast, a frontier set considers pairs of cells, A and B. For each pair, it lists two sets of cells, F-AB and F-BA. By definition, from no cell in F-AB is any cell in F-BA visible and vice-versa. Our initial use of frontier sets has been to enable scalability in distributed networking. In this paper we build on previous work by showing how to avoid pre-computing frontier sets. Our previous algorithm, required O(N-3) space in the number of cells, to store pre-computed frontier sets. Our new algorithm pre-computes an enhanced potentially visible set that requires only O(N-2) space and then computes frontiers only as needed. Network simulations using code based on the Quake II engine show that frontiers have significant promise and may allow a new class of scalable peer-to-peer game infrastructures to emerge.