Parallel Visibility Test and Occlusion Culling in Avango Virtual Environment Framework

Abstract

Real-time visibility test is an attractive feature for Virtual Environment (VE) applications where large datasets should be interactively explored. In such scenes most of the objects are usually occluded by other ones, and their omission from rendering can significantly accelerate the graphical performance. In this paper we present our novel approach for occlusion culling and its implementation in VE system Avango1. Visibility test module performs real-time update of the list of visible objects by means of color labeling and either hardware or software histogramming of corresponding color buffer. Exploiting the distribution capabilities of Avango, the main draw and visibility test processes are parallelized to different computers running Irix or Linux. Being applied to an architectural model containing 260,000 textured triangles, our method accelerates the graphical performance from 8 to 32 stereoimages/sec.