Real-time Rendering of Large-scale Terrain in the Flight Simulator

Large terrain is an important component of the virtual visual environment in the flight simulator. This paper presents a view-dependent dynamic LOD algorithm which is inspired by the geometry clipmap, and has some supplement or improvement in data structure, refinement criterion, rendering way, etc. The algorithm treats the terrain data as vertex texture; carries out uniform management on the terrain geometry data sets, terrain color texture and normal vectors using a hierarchy like the clipmap; and applies the identical spatial partition, transition scheme and update method to these data. The experiment shows that the algorithm can have much smaller memory requirements, make full use of the advantage of GPU and produce realistic and continuous images with the interactive speed. Especially, virtual clipmap support can make sure the algorithm fit the applications which have gigantic terrain range or need higher precision, so it has great extensibility and broad application prospects.