Method for automatically smoothing object level of detail transitions for regular objects in a computer graphics display system

Abstract

A database and execution hierarchy for computer graphics display systems that breaks LOD transitions into two functional steps. The first is the geometry transition, and the second is the detail transition, provided by texture maps. The geometric transition applies conformal fixed vertex decimation methods to create multiple levels of detail with a shared vertex coordinate database. Transitions between LOD's are made seamless by creating the multiple LOD levels with macrogrids of fixed, non-decimated vertices. These are generated using a hierarchical approach that reduces the number of fixed points in the macrogrid at each successive level. Visual anomalies associated with color and texture transitions are reduced by using texture maps to ensure consistent detail transitions for pixels between LOD's. The textures capture the detail information of the highest LOD using orthographic rendering on a grid matching the geometric macrogrid. Database storage size and transmission rate are optimized. Vertex storage is minimized by reuse for cospatial LOD's. Surface normal descriptions can also be eliminated, saving substantial additional space, and reducing the setup calculations for a large portion of the scene since lighting is precalculated and can be disabled for higher LOD's. Texture indices can also be reused for grouped LOD's.