Large-Scale 3D Terrain Generation Rendering And Application Based On Real Geographic Information

With the rapid development of virtual reality technology,virtual reality has been widely applied to simulation interaction,military medical,game entertainment,aerospace and other fields.Large-scale terrain simulation has also become an important part of the virtual environment and has received attention.At present,with the increasing scale of the terrain,the higher precision,and the lack of rendering conditions of single-machine hardware,the real-time rendering of large-scale terrain has become a difficult problem in research.Mainly in terrain generation,model simplification and rendering optimization.In order to realize real-time display and realistic rendering of large-scale terrain data,this paper focuses on the key technologies in large-scale terrain generation.main tasks as follows:Firstly,propose a digital elevation model(DEM)to generate a regular grid processing flow in the scene coordinate system,Through the Geospatial Data Abstraction Library(GDAL),it includes DEM data reading,coordinate system transformation and affine transformation.The complete flow to the scene coordinates.The converted latitude and longitude error is obtained by comparing the original latitude and longitude with the new latitude and longitude coordinates obtained by the inverse transformation.The results show that the mean value of latitude and longitude error is small,and the algorithm has high conversion precision.Second,study the organization and scheduling loading methods of terrain data.The data organization is layered by terrain partitioning and quadtree,and the block simplification method of the triangle index table is introduced.Data scheduling uses a multi-threaded and object pooling mechanism.Multi-threading participates in the recursive cutting process of quadtree,and improves the method of intersecting detection and clipping strategy of bounding box in cropping.Use object pools to centrally manage block objects,including load,unload,and destroy processes.Under the different terrain data size,the optimization algorithm can increase the frame rate by at least 1.73 times and up to 20.74 times.Finally,combined with the terrain simplification algorithm and texture mapping technology of this paper,the 3D visualization rendering system of large-scale terrain is completed,and the performance of the system is evaluated.From the evaluation results,in the system performance test,the consistency of picture rendering can be maintained while rotating and moving,and the average frame rate is above 500 fps,which reflects the good system performance and meets the real-time requirements of the simulation system.In addition,the terrain visualization system is applied to the submarine pipeline simulation maintenance system,which restores a real pipeline operation environment and implements a complete interactive operation training process.