Efficient Visibility for Distributed Virtual Urban Environments: Based on Occlusion Culling Method

This book focuses on the utilization of occlusion culling for the real-time visualization of distributed virtual urban environments. Today's graphics hardware renders all the primitives in any order and uses z-buffer to determine which primitives are visible on a per-pixel basis. However, visibility is computed in the last stage of rendering pipeline and every rendered primitive is not visible in the final image. Early culling of the invisible primitives in a complex scene is valuable for efficiency in the conventional rendering pipeline. This may reduce the number of primitives that will be processed in the rest of the pipeline. In this work, we propose an efficient visibility estimation method for distributed virtual urban environments. The proposed method is based on occlusion culling to identify and cull the occluded parts of the scene. This not only computes conservative potential visible set (PVS) for each client but also assures the computed PVS to be available at the client on-time and reduces the network traffic by grouping the clients which may see each others dynamically.