Research On Technique Of Real-time 3D Terrain Roaming In The Air

Realistic 3D terrain is one of the important components of virtual reality system and real time emulation. With the quickly development of virtual reality and emulation, the generation and modeling of high realistic terrain becomes more and more important. This thesis focuses on real-time display of large scale terrain and the representation of realistic terrain and landform .The principal contents are as follows:Several classic methods for getting the information of the elevation of the DEM were researched here with the emphasis of extracting the elevation from contour maps and the fractal algorithm. The DEM data used in the thises was generated in a new way that from the the traditional random midpoint displacement method with a control of contour maps. Compareing with traditional methods, it is easy getting and keeping the basic information of the real terrain with sufficient details.Typical terrain simplification and constructions of multi-resolution model algorithms were researched and described with the emphasis of the tree structure based on RGS. A self-adapting binary tree was constructed based on RSG was built. And how to determine the view-dependent judgment function was discussed. Besides the two traditional factors the speed variation was considered here to make the system scene better quality and efficiency.A real time flying terrain system was built on the OpenGL lib and the VC++ .The terrain, airplane and sky were rendered.