Optimized HLOD refinement driven by hardware occlusion queries

Abstract

We present a new method for integrating hierarchical levels of detail (HLOD) with occlusion culling. The algorithm refines the HLOD hierarchy using geometric criteria as well as the occlusion information. For the refinement we use a simple model which takes into account the possible distribution of the visible pixels. The traversal of the HLOD hierarchy is optimized by a new algorithm which uses spatial and temporal coherence of visibility. We predict the HLOD refinement condition for the current frame based on the results from the last frame. This allows an efficient update of the front of termination nodes as well as an efficient scheduling of hardware occlusion queries. Compared to previous approaches, the new method improves on speed as well as image quality. The results indicate that the method is very close to the optimal scheduling of occlussion queries for driving the HLOD refinement. © Springer-Verlag Berlin Heidelberg 2007.