A bimodal empty space skipping of ray casting for terrain data

Due to the increasing resolution of terrain data for realistic scenes in pervasive games, ray casting is facing the problem of slow rendering speed which is not appropriate for real-time visualization. We present a novel empty space skipping method that uses two different approaches simultaneously. This method accelerates the traditional ray casting by adding a pass called shell propagation. It propagates the bounding boxes that tightly enclose the terrain surfaces to skip wider empty region in rasterization stage. Because the rasterization process is performed on fixed pipeline of graphics hardware, it is much faster than the case of applying conventional space leaping to entire terrain data. We can efficiently reduce computing time since empty space skipping is applied on individual bounding boxes rather than the entire terrain.