Development Of Multi-resolution Scene Roaming System Based On Performer

The virtual reality technology plays more and more important role in many fields, such as military training, system simulation, architecture design, 3D game, simulation of drive training, virtual assemblage and virtual design. Moreover, Roaming of virtual scene is an important development and study direction of virtual reality. This dissertation builds up and realizes a roaming system of virtual environment based on the PC architecture. How to construct virtual scene is one of the key technologies of realizing roaming system. This dissertation constructs the virtual scene with satellitic image and aerial photography. But unlike other roaming system, the system bases on the satellitic image and aerial photography of different geographical areas and different resolution. And also, the system makes multi-resolution textures for every geographical area. In order to guarantee the real-time quality and the quality of visual scene of the roaming system, this dissertation presents and realizes a real-time and view-dependent LOD algorithm, which computes real-time 3D scene in the roaming process. The emphasis of this dissertation is on integrating and processing the data of different source and resolution, designing feasible schedule rule and realizing rapid and efficient roaming of image layers and model layer. The system's data source includes the satellitic image of China, the midstream and downstream of the Changjiang River, Hubei and Qingjiang Valley, aerial photography of Geheyan power station. We realize the roaming system on PC with C++ language, OpenGL and Performer, which is a high-performance software package of real-time 3D scene development. This system roams on different geographical areas and different layers. It offers more and more accurate earth's surface texture information and 3D topographical information.