Study On Some Technical Problems In Real-time Rendering Of Large-scale Scenes

The aim of real-time rendering of large-scale scenes is to ensure that the user can have real-time operation on the object model of large-scale scenes at interactive frame rate, at the same time, calculate player's position and orientation in real time, render the player of scenes dynamically, with point of view's change, screen's refresh rate should make the human eyes not detect the flicker, usually 20-30 frames per second, frame-skipping and system halted phenomenon does not happen, memory is not exhausted. With the development of digital photogrammetry and remote sensing technology, massive data can be got possibly, these massive data constitute large-scale virtual reality scenes, of which there are tens of thousands of polygons or even millions of polygons, together with high-resolution satellite image as a texture to spend a lot of storage space, meanwhile, may need to have environmental illumination, animation, sound effects and other effects to enhance a sense's reality, if property characteristics and location characteristics of the geographical data reproduce in real time, even if the advanced hardware configuration also appeared to be inadequate. Research on real-time rendering of large-scale virtual reality scenes has become a hot topic, which has a wide prospect of application at the digital city building, 3D games, virtual battlefield, three-dimensional geographical information systems development, and many other fields.Based on studying the theory of virtual scenes rendering and software-based acceleration technology, this paper uses Multigen-Creator for modeling tools and Vega for the scene-driven platform, in the absence of expensive SGI graphics workstations and other hardware support, the employment of Polymesh algorithm, Irregular Mesh algorithm to improve Polymesh algorithm, Delaunay algorithm and its improved algorithm CAT, to generate terrain levels of detail for the experimental region, through the LOD generation, statistics the polygon numbers of LOD models, analyse the LOD error, calculate the generation speed and summarize the application scope of the four algorithms to draw the advantages and disadvantages; The employment of large area database management technology to manage and attemper the models of large-scale scenes beyond the ability of graphics hardware in real time, which not only reduces the polygon numbers of scenes, improve rendering efficiency and make sure the frames uniformity of real-time rendering. Design and empolder the virtual simulation system based on the different point of view (surface and air), the virtual simulation system can run smoothly and meet the requirements of real-time in PC though testing, which makes a useful attempt to real-time rendering of large-scale of scenes.