Progressive cache replacement for massive peer-to-peer WebVR worlds

As the popularity of WebVR applications rises in recent years, a great disparity exists between the huge 3D content on servers and the limited cache capacity on clients. In order to alleviate server loading, peer-to-peer (P2P)-based 3D content distribution has been proposed recently. However, given the limited cache sizes at clients, how to maintain and replace the cache content effectively becomes an important issue. We present a progressive scene replacement mechanism (PSRM) in this paper to support interactive walkthrough in P2P-based large-scale WebVR worlds. First, we define a new metric called preservation degree, based on both the visual attention paid by the user and the content's potential relevance for sharing. Second, cached objects are replaced progressively with ascending order in terms of their preservation degrees. Experimental results have shown that PSRM enables users with limited cache to walkthrough a large-scale WebVR world with high visual quality; while download requests handled by the servers are reduced significantly.