NPSNET: Hierarchical Data Structures for Real-Time Three-Dimensional Visual Simulation.

摘要

NPSNET is a low-cost visual simulation system designed and constructed at the Naval Postgraduate School. NPSNET uses digital terrain data and renders scenes involving vehicles, aircraft, cultural features, and natural features in real-time. The implementation of a terrain paging algorithm in NPSNET is discussed. Terrain paging expands the terrain area available for simulation and overcomes the limits of main memory size. Hierarchical data structures commonly used in visual simulation systems are surveyed. The generation of a multi-resolution terrain dataset and the implementation of a hierarchical data structure are explained. The multi-resolution dataset is created by generating lower resolution descriptions of polygons from the original data. The hierarchical data structure used in NPSNET, based on quadtrees, provides a means to attenuate the resolution of terrain over distance and cull those portions of terrain outside of the user's field of view.