Design And Study Of Embedded 3d Terrain Visualization

In recent years,with the integration of Geographic Information Science and Computer Graphics, a new field called Three-Dimentional Terrain Visualization is emerging. It uses various geographic data which collected by modern measurement methods and three-dimentinal image technology to visulize the terrain, then vividly simulates real-world geography environment by texture mapping. This techology is of great importance upon national defence, transportion, agriculture, forestry and entertainment.This thesis mianly discusses three-dimentional terrain under embedded operating systems. The research upon embedded three-dimentional terrain visualization has just started in our country. It's insufficient compared with foreign products. Accordingly, it's necesssry to research and design three- dimentional terrain visualization.This thesis introduces the generating methods of three-dimentional terrain. First discuss the generating method of regular triangular mesh model. Next, illustrates Delauay's triangulation theory, analyses Delaunay triangulation algorithm. Then combines the theory and the algorithm to generate the terrain model, optimizes the insert algorithm, and finally realizes the constrainted Delaunay triangulation algorithm and the data processing and organization in three-dimentional cicumstance. It can divide the DEM data and texture data according to some requirement, manage each terrain sub-block and texture sub-block to make them have different levels of detail.Builds an index system, and stores the DEM data, texture data into the embedded database, organizes the data of three-dimentional scene data with scene quadtree strucure to facilitate the implementation of scheduling of scene data, improve the effiency of the scene display.This thesis designs data scheduling solution of the embedded three-dimentional scene during its display process. Improves the speed of scene scheduling by simplifying scene visibility's judgement. Synchronizes the scene scheduling with multithreading technology. Analyzes the motion mode of viewpoint. In order to predict the scheme of the next data operation. Preload these datas to memory to ensure the smoth show of the scene.