Nysjö,F.
Abstract:
Active grid cells in scalar volume data are typically identified by many isosurface rendering methods when extracting another representation of the data for rendering. However, the use of grid cells themselves as rendering primitives is not extensively explored in the literature. In this paper, we propose a cluster-based data structure for storing the data of active grid cells for fast cell rasterisation via billboard splatting. Compared to previous cell rasterisation approaches, eight corner scalar values are stored with each active grid cell, so that the full volume data is not required during rendering. The grid cells can be quickly extracted and use about 37 percent memory compared to a typical efficient mesh-based representation, while supporting large grid sizes. We present further improvements such as a visibility buffer for cluster culling and EWA-based interpolation of attributes such as normals. We also show that our data structure can be used for hybrid ray tracing or path tracing to compute global illumination.