The GPU-based Technology Of Real-time Global Terrain Rendering

The Real-time Visualization Technology of Large Terrain has a wide use in the field of battle command, flight simulation, amusement and the others. It is a key and hot topic research field of Visual Reality, Battlefield Environment Simulation and 3D GIS. By using the Global Digital Elevation Model and high resolution satellite image as data resources, this paper focuses on the Large Terrain region Visualization Technology based on the new Graphic Processing Unit (GPU), and improves the rendering speed of massive terrain data. The main contents and contributions in this thesis can be summarized as follows:1. On the basis of large data pyramid hierarchy model, this paper designs the methods of the delamination, tiling, data storing and indexing policy, and realizes a data engine which supports the file system and the database system.2. By the studying of the new version Graphic Rendeing Engine, it uses the programmable features of modern GPU, and modifies the Geometry Clipmap algorithm and uses the texture matrix to simplify the generation of texture coordinate, which can render effectively through a new high performance frustum culling method and crack filling technique. Combined the pyramid hierarchy model, this algorithm can carry out the real-time visualization of massive terrain data.3. This thesis designs and realizes a terrain rendering engine which supports Multi-thread rendering and progressive data transfer. It effectively advances the rendering speed of massive terrain data. By using of vertex shader this engine realizes the rendering of "mosaic" local high-resolution terrain data.4. It intergrates the terrain data engine and rendering engine, develops "the Global Terrain Real-time Rendering Antetype System", which can realize the 3D real-time rendering via multiresolution terrain data of the global area. The system is used widely in the field of digital earth, 3D GIS and the visualization of space environment.5. Focusing on the international trend of GPU and CPU development, this thesis proposes the basic rendering method which uses the GPU and multi-core CPU to realize the real-time visualization of massive terrain data.