Decoupling Polygon Rendering from Geometry using Rasterization Hardware

The dramatically increasing size of polygonal models resulting from 3D scanning devices and advanced modeling techniques requires new approaches to reduce the load of geometry transfer and processing. In order to supplement methods like polygon reduction or geometry compression we suggest to exploit the processing power and functionality of the rasterization and texture subsystem of advanced graphics hardware. We demonstrate that 3D-texture maps can be used to render voxelized polygon models of arbitrary complexity at interactive rates by extracting isosurfaces from distance volumes. Therefore, we propose two fundamental algorithms to limit the rasterization load: First, the model is partitioned into a hierarchy of axis-aligned bounding boxes that are voxelized in an error controlled multi-resolution representation. Second, rasterization is restricted to the thin boundary regions around the isosurface representing the voxelized geometry. Furthermore, we suggest and simulate an OpenGL extension enabling advanced per-pixel lighting and shading. Although the presented approach exhibits certain limitations we consider it as a starting point for hybrid solutions balancing load between the geometry and the rasterization stage and we expect some influence on future hardware design.