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Visibility based prefetching with simulated annealing

Çevikbaş, Şafak Burak
Complex urban scene rendering is not feasible without culling invisible geometry before the rendering actually takes place. Visibility culling can be performed on predefined regions of scene where for each region a potential visible set of scene geometry is computed. Rendering cost is reduced since instead of a bigger set only a single PVS which is associated with the region of the viewer is rendered. However, when the viewer leaves a region and enters one of its neighbors, disposing currently loaded PVS and loading the new PVS causes stalls. Prefetching policies are utilized to overcome stalls by loading PVS of a region before the viewer enters it. This study presents a prefetching method for interactive urban walkthroughs. Regions and transitions among them are represented as a graph where the regions are the nodes and transitions are the edges. Groups of nodes are formed according to statistical data of transitions and used as the prefetching policy. Some heuristics for constructing groups of nodes are developed and Simulated Annealing is utilized for constructing optimized groups based on developed heuristics. The proposed method and underlying application of Simulated Annealing are customized for minimizing average transition cost.